Patent Publication Number: US-11641795-B2

Title: Lawn mower

Description:
RELATED APPLICATION INFORMATION 
     This application claims the benefit under 35 U.S.C. § 119a of Chinese Patent Application No. CN 201921000842.1, filed on Jun. 28, 2019, Chinese Patent Application No. CN 201910576318.7, filed on Jun. 28, 2019, and Chinese Patent Application No. CN 201921000773.4, filed on Jun. 28, 2019, each of which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present application relates to an electric machine, for example, to a lawn mower. 
     BACKGROUND 
     As a basic operation of lawn trimming, mowing requires the use of simple and efficient mowing machinery to complete the mowing task with guaranteed the quality and quantity. Lawn mowers have been widely used in the trimming of various kinds of lawns. As the functional element of the lawn mower, the structural design of the blade greatly affects the cutting performance of the lawn mower. 
     Lawn mowers can be divided into engine-driven and motor-driven by energy source. Among them, the motor-driven lawn mower generally uses battery packs as energy source, which has the advantages of less noise and pollution. However, considering the load problem, the motor-driven lawn mower in the related art has an unreasonable blade structure, which results in a large load on the motor and a low cutting efficiency. 
     SUMMARY 
     In one example, a lawn mower includes: a blade assembly configured to perform a cutting function; a deck formed with an accommodation space for accommodating at least a portion of the blade assembly; a motor configured to drive the blade assembly to rotate about a rotation axis; and a battery pack configured to provide power source to the motor; wherein the blade assembly includes: a first blade formed with a first cutting portion for cutting grass; and a second blade formed with a second cutting portion for cutting grass; wherein the volume of the smallest cylinder surrounding the first blade and the second blade is defined as a swept volume of the blade assembly, the first cutting portion and the second cutting portion are located in a space surrounded by the smallest cylinder when the blade assembly rotates around the rotation axis, and the swept volume of the blade assembly is greater than or equal to 400 cm 3  and less than or equal to 8000 cm 3 ; and wherein a positioning portion is formed on one of the first blade and the second blade, an engaging portion that engages with the positioning portion is formed on the other, the second blade is fixed relative to the first blade in a circumferential direction around the rotation axis or rotatable within a predetermined angle range when the positioning portion and the engaging portion engage with each other. 
     In one example, the swept volume of the blade assembly is greater than or equal to 600 cm 3  and less than or equal to 6800 cm 3 . 
     In one example, the swept volume of the blade assembly is greater than or equal to 1000 cm 3  and less than or equal to 5000 cm 3 . 
     In one example, the first blade and the second blade are formed integrally or separately. 
     In one example, the first blade and the second blade are formed separately, and a ratio of the mass of the first blade to the mass of the second blade is greater than or equal to 0.5 and less than or equal to 1. 
     In one example, a phase angle formed by the first cutting portion and the second cutting portion is greater than or equal to 0 degrees and less than 90 degrees. 
     In one example, a maximum length of a line connecting any two points of the projection of the blade assembly in a plane perpendicular to the rotation axis and the projection of the rotation axis in the plane is a rotation diameter D of the blade assembly, and the rotation diameter D is greater than or equal to 200 mm and less than or equal to 700 mm. 
     In one example, the mass of the blade assembly is greater than or equal to 0.35 kg and less than or equal to 1.8 kg. 
     In one example, a length of a projection of the first cutting portion in a plane perpendicular to the rotation axis is greater than or equal to 10 mm and less than or equal to 600 mm, and a length of a projection of the second cutting portion in the plane perpendicular to the rotation axis is greater than or equal to 10 mm and less than or equal to 600 mm. 
     In one example, a sum of the number of the first cutting portions and the number of the second cutting portions is the number of cutting portions of the blade assembly, and ratio of the swept volume of the blade assembly to the number of the cutting portions of the blade assembly is greater than or equal to 50 cm 3  and less than or equal to 4000 cm 3 . 
     In one example, the positioning portion is a positioning hole or a positioning groove, and the engaging portion is a protrusion portion that engages with the positioning hole or the positioning groove. 
     In one example, the positioning portion has a geometric center, a distance from the geometric center to the rotation axis is a positioning radius, and the positioning radius is greater than 0 mm and less than or equal to 50 mm. 
     In one example, a lawn mower includes: a blade assembly configured to perform a cutting function; a deck formed with an accommodation space for accommodating at least a portion of the blade assembly; a motor configured to drive the blade assembly to rotate about a rotation axis; and a battery pack configured to provide power source for the motor; wherein the blade assembly includes: a first blade formed with a first cutting portion for cutting grass; and a second blade formed with a second cutting portion for cutting grass; wherein the volume of the smallest cylinder surrounding the first blade and the second blade is defined as a swept volume of the blade assembly, the first cutting portion and the second cutting portion are located in a space surrounded by the smallest cylinder when the blade assembly rotates around the rotation axis, and the swept volume of the blade assembly is greater than or equal to 400 cm 3  and less than or equal to 8000 cm 3 ; and wherein the lawn mower further comprises a connecting assembly for connecting the blade assembly so that the second blade is fixed relative to the first blade in a circumferential direction around the rotation axis or rotatable within a predetermined angle range. 
     In one example, a lawn mower includes: a blade assembly configured to perform a cutting function; a deck formed with an accommodation space for accommodating at least a portion of the blade assembly; a motor configured to drive the blade assembly to rotate about a rotation axis; and a battery pack configured to provide power source for the motor; wherein the blade assembly includes: a first blade formed with a first cutting portion for cutting grass; and a second blade formed with a second cutting portion for cutting grass; and wherein the volume of the smallest cylinder surrounding the first blade and the second blade is defined as a swept volume of the blade assembly, the first cutting portion and the second cutting portion are located in a space surrounded by the smallest cylinder when the blade assembly rotates around the rotation axis, and the swept volume of the blade assembly is greater than or equal to 400 cm 3  and less than or equal to 8000 cm 3 . 
     In one example, the swept volume of the blade assembly is greater than or equal to 600 cm 3  and less than or equal to 6800 cm 3 . 
     In one example, the swept volume of the blade assembly is greater than or equal to 1000 cm 3  and less than or equal to 5000 cm 3 . 
     In one example, the first blade and the second blade are formed separately, and a ratio of the mass of the first blade to the mass of the second blade is greater than or equal to 0.5 and less than or equal to 1. 
     In one example, a phase angle formed by the first cutting portion and the second cutting portion is greater than or equal to 0 degrees and less than 90 degrees. 
     In one example, a maximum length of a line connecting any two points of the projection of the blade assembly in a plane perpendicular to the rotation axis and the projection of the rotation axis in the plane is the rotation diameter D of the blade assembly, and the rotation diameter D is greater than or equal to 200 mm and less than or equal to 700 mm. 
     In one example, the mass of the blade assembly is greater than or equal to 0.35 kg and less than or equal to 1.8 kg. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a schematic diagram of a lawn mower provided in a first example; 
         FIG.  2    is a plan view of a partial structure of the lawn mower of  FIG.  1   ; 
         FIG.  3    is a perspective view of a partial structure of the lawn mower of  FIG.  1   ; 
         FIG.  4    is a plan view of a partial structure of a blade assembly of the lawn mower of  FIG.  1   ; 
         FIG.  5    is a cross-sectional view of a partial structure of the lawn mower of  FIG.  1   , wherein a mounting assembly is in a first mounting state; 
         FIG.  6    is an exploded view of a partial structure of the lawn mower of  FIG.  1   ; 
         FIG.  7    is a schematic view of a partial structure of the lawn mower provided in the first example, wherein the mounting assembly is in a second mounting state; 
         FIG.  8    is a schematic diagram of a partial structure of the lawn mower provided in the first example, wherein the mounting assembly is in the second mounting state; 
         FIG.  9    is an exploded view of a blade assembly of the lawn mower of  FIG.  1   ; 
         FIG.  10    is a schematic diagram of a first blade and a second blade of the lawn mower of  FIG.  1   ; 
         FIG.  11    is a schematic diagram of a partial structure of a lawn mower provided in a second example; 
         FIG.  12    is a schematic diagram of a blade assembly and a connecting assembly of a lawn mower provided in a third example; 
         FIG.  13    is a schematic diagram of a blade assembly of a lawn mower provided in a forth example; 
         FIG.  14    is a plan view of the blade assembly in  FIG.  13   ; 
         FIG.  15    is a plan view of a second blade of the blade assembly in  FIG.  13   ; 
         FIG.  16    is a plan view from another angle of the second blade of the blade assembly in  FIG.  13   ; 
         FIG.  17    is a schematic diagram of a partial structure of a lawn mower provided in a fifth example; 
         FIG.  18    is a cross-sectional view of the structure in  FIG.  17   ; 
         FIG.  19    is an exploded view of the partial structure of the lawn mower of  FIG.  17   ; 
         FIG.  20    is a schematic diagram of a partial structure of a lawn mower provided in a sixth example; 
         FIG.  21    is a plan view of a blade assembly and a mounting assembly of the lawn mower provided in the sixth example; 
         FIG.  22    is an exploded view of the partial structure of the lawn mower of  FIG.  20   ; 
         FIG.  23    is a schematic diagram of a partial structure of a lawn mower provided in a seventh example; 
         FIG.  24    is a cross-sectional view of the structure in  FIG.  23   ; 
         FIG.  25    is an exploded view of the structure in  FIG.  23   ; 
         FIG.  26    is a schematic diagram of a partial structure of a lawn mower provided in an eighth example; 
         FIG.  27    is a schematic diagram of a lawn mower connected with a grass pressing assembly provided in a ninth example; 
         FIG.  28    is a perspective view of the grass pressing assembly in  FIG.  27   ; 
         FIG.  29    is a plan view of the grass pressing assembly in  FIG.  27   ; 
         FIG.  30    is a cross-sectional view of the grass pressing assembly in  FIG.  27   ; 
         FIG.  31    is a schematic diagram of a grass pressing assembly connected to a lawn mower provided in a tenth example; 
         FIG.  32    is a perspective view of a lawn mower provided in an eleventh example; 
         FIG.  33    is a bottom view of the lawn mower of  FIG.  32   ; 
         FIG.  34    is a circuit diagram of the lawn mower of  FIG.  32   ; 
         FIG.  35    is a schematic diagram of the connection of a first signal line of the lawn mower of  FIG.  32    to a first output circuit board and a second output circuit board; 
         FIG.  36    is a circuit diagram of a lawn mower provided in a twelfth example; 
         FIG.  37    is a schematic diagram of a partial structure of the lawn mower of  FIG.  32   ; 
         FIG.  38    is a perspective view of a deck in the lawn mower of  FIG.  32   ; 
         FIG.  39    is a plan view of the deck in  FIG.  38   ; 
         FIG.  40    is a cross-sectional view of the deck in  FIG.  39    along line V-V; 
         FIG.  41    is a perspective view of the deck of  FIG.  38    when connected to a plug; 
         FIG.  42    is a schematic diagram of a lawn mower provided in a thirteenth example; 
         FIG.  43    is a perspective view of the lawn mower of  FIG.  42   ; 
         FIG.  44    is a plan view of a blade assembly of the lawn mower of  FIG.  42   ; 
         FIG.  45    is an exploded view of the blade assembly in  FIG.  44   ; 
         FIG.  46    is a plan view of a partial structure of the blade assembly in  FIG.  45   ; 
         FIG.  47    is a schematic diagram of a lawn mower provided in a fourteenth example; 
         FIG.  48    is a perspective view of a blade assembly of the lawn mower of  FIG.  47   ; 
         FIG.  49    is a plan view of a blade of the blade assembly of  FIG.  48   ; 
         FIG.  50    is a cross-sectional view of the blade in  FIG.  49   ; 
         FIG.  51    is a schematic diagram of a blade assembly of a lawn mower provided in a fifteenth example; 
         FIG.  52    is a plan view of a blade of the blade assembly of  FIG.  51   . 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    is a schematic diagram of a lawn mower  100  provided in a first example of the present application. Depending on the operation mode of the user, the lawn mower  100  in the present application may be either a hand-push lawn mower or a riding lawn mower. This example uses a hand-push lawn mower driven by a motor as an example for description. All “assembly” in this application refer to a combination including at least one component or part, which realizes a specific function through interaction or coordination. For the convenience of explaining the technical solution of the present application, the up-down direction is defined as shown in  FIG.  1   . 
     As shown in  FIGS.  1 - 3   , the lawn mower  100  includes a blade assembly  11 , a deck  12 , a motor  13 , and a battery pack. The blade assembly  11  is configured to perform the cutting function of the lawn mower  100 ; the deck  12  is formed with an accommodation space for accommodating at least part of the blade assembly  11 ; in this example, the blade assembly  11  is located inside the accommodation space; the motor  13  drives the blade assembly  11  to rotate about the rotation axis  100 ′, and the motor  13  is located above the deck  12  and forms a coaxial rotation with the blade assembly  11  about the rotation axis  100 ′. In an example, the motor  13  includes a motor shaft, and the lawn mower  100  further includes a drive shaft  14  that drives the blade assembly  11  to rotate. The drive shaft  14  may be a motor shaft, and a transmission mechanism may be provided between the motor  13  and the blade assembly  11  so that the motor  13  and the drive shaft  14  form a non-coaxial rotation. The battery pack provides a power source for the motor  13 . The lawn mower  100  also includes a fan  15  connected to the drive shaft  14 ; the fan  15  rotates about an axis that is parallel or coincident with the rotation axis  100 ′. 
     When the motor  13  is started to drive the blade assembly  11  to rotate about the rotation axis  100 ′ and the tip linear velocity of the blade assembly  11  is greater than or equal to 40 m/s and less than or equal to 100 m/s, the working time of the lawn mower  100  with 100 WH energy consumption of the battery pack is defined as the hectowatt-hour battery life of the lawn mower  100 , and the hectowatt-hour battery life of the lawn mower  100  is greater than or equal 4 min and less than or equal to 30 min; in one example, the hectowatt-hour battery life of the lawn mower  100  is greater than or equal to 5 min and less than or equal to 20 min; in other examples, the hectowatt-hour battery life of the lawn mower  100  is greater than or equal to 6 min and less than or equal to 15 min. In this example, the hectowatt-hour battery life of the lawn mower  100  is about 12 min. Since the lawn mower  100  of the present example has the blade assembly  11  with better structure design, smaller load and higher cutting efficiency, during operation the lawn mower  100  has a hectowatt-hour battery life in the above range, such that the lawn mower  100  has a good cutting performance. The battery pack here only refers to the battery pack that supplies power to the motor  13  to drive the blade assembly  11  to rotate. 
     In addition, when the motor  13  drives the blade assembly  11  to rotate about the rotation axis  100 ′ at no load, the working time of the lawn mower  100  with 100 WH energy consumption of the battery pack is defined as the no-load battery life of the lawn mower  100 , and the no-load battery life of the lawn mower  100  is greater than or equal to 9 min and less than or equal to 35 min; in one example, the no-load battery life of the lawn mower  100  is greater than or equal to 12 min and less than or equal to 33 is min; in other examples, the no-load battery life of the lawn mower  100  is greater than or equal to 18 min and less than or equal to 30 min. In this example, the no-load battery life of the lawn mower  100  is about 22 min. Since the lawn mower  100  of the present example has the blade assembly  11  with better structure design, smaller load and higher cutting efficiency, as well as reasonable no-load condition settings, during operation the lawn mower  100  has a no-load battery life in the above range, such that the lawn mower  100  has a good cutting performance. 
     As shown in  FIGS.  2 - 5   , the blade assembly  11  includes a first blade  111  and a second blade  112 , and the first blade  111  and the second blade  112  are respectively formed with a first cutting portion  111   a  and a second cutting portion  112   a  that are configured to cut grass. When the entirety constructed by the first blade  111  and second blade  112  rotate about the rotation axis  100 ′, the first cutting portion  111   a  and the second cutting portion  112   a  performs mowing. In this example, the cutting portions refer to a structure having a cutting function to cut vegetation; the cutting portion may be a common cutting portion or a cutting structure different from the cutting portion. A cutting portion refers to an integrally formed or continuous structure. 
     In a direction parallel to the rotation axis  100 ′, the second cutting portion  112   a  is located below, but not limited to directly under, the first cutting portion  111   a ; or the second cutting portion  112   a  and the first cutting portion  111   a  are at least partially within the same plane. In this example, the first blade  111  and the second blade  112  are two blades formed separately. The first blade  111  is located above the second blade  112  relative to the ground in a direction parallel to the rotation axis  100 ′. The first blade  111  and the second blade  112  rotate synchronously. As shown by the arrows in  FIG.  2   , the first blade  111  and the second blade  112  rotate coaxially and synchronously along the rotation direction A about the rotation axis  100 ′. 
     The lawn mower  100  also includes a control system configured to control the operation of the motor  13 . When the lawn mower  100  has no load, the sum of the input power of the motor  13 , the input power of the control system, and the input power of the blade assembly  11  is the no-load input power of the lawn mower  100 ; the no-load input power is greater than or equal to 100 W and less than or equal to 380 W, in this example, the no-load input power is greater than or equal to 200 W and less than or equal to 300 W. 
     In one example, no-load means that the blade assembly  11  of the lawn mower  100  rotates at a predetermined speed under atmospheric pressure, and the blade assembly  11  has no external load. 
     The volume of the smallest cylinder  11 ′ surrounding the first blade  111  and the second blade  112  is defined as the swept volume of the blade assembly  11 . When the blade assembly  11  rotate about the rotation axis  100 ′, the first cutting portion  111   a  and the second cutting portion  112   a  are both located in the space surrounded by the smallest cylinder  11 ′. As shown in  FIG.  2   , the rectangle indicated by the dotted line is a plan view of the cylinder  11 ′ that surrounds the first blade  111  and the second blade  112  in this example. The swept volume of the blade assembly  11  is the volume of the cylinder  11 ′, and the volume of the cylinder  11 ′ is about the volume of the cylinder  11 ′ with the rotation diameter D of the blade assembly  11  as the diameter referring to  FIG.  4   , and the maximum height of the blade assembly  11  in the direction parallel or coincident with the rotation axis  100 ′ as the height. The rotation diameter D of the blade assembly  11  is the maximum length of the line connecting any two points of the projection of the blade assembly  11  in a plane perpendicular to the rotation axis  100 ′ and the projection of the rotation axis  100 ′ in the plane. In this example, since the first blade  111  and the second blade  112  are both perpendicular to the rotation axis  100 ′, and the first blade  111  and the second blade  112  are coaxially mounted to the drive shaft  14 ; the first blade  111  is located directly above the second blade  112 . The swept volume of the blade assembly  11  is about the volume of the cylinder  11 ′ with the maximum distance from any point on the blade assembly  11  to the rotation axis  100 ′ as the radius, and the maximum sum of the heights of the first blade  111  and the second blade  112  parallel to the rotation axis  100 ′ as the height. In one example, the heights of the first blade  111  and the second blade  112  are respectively the maximum dimensions of the first blade  111  and the second blade  112  in the direction parallel to the rotation axis  100 ′ when the blade assembly  11  is mounted to the drive shaft  14 . 
     In this example, the swept volume of the blade assembly  11  is greater than or equal to 400 cm 3  and less than or equal to 8000 cm 3 . When the swept volume of the blade assembly  11  is kept within this range, the lawn mower  100  has a relatively small load, in other words, when the swept volume of the blade assembly  11  is kept within this range, the lawn mower  100  has a relatively small load while the double blades guarantee the cutting performance of the lawn mower  100 , thereby enabling the lawn mower  100  to have a high cutting efficiency. In this example, the swept volume of the blade assembly  11  is greater than or equal to 600 cm 3  and less than or equal to 6800 cm 3 . In one example, the swept volume of the blade assembly  11  is greater than or equal to 1000 cm 3  and less than or equal to 5000 cm 3 . 
     The structure of the blade assembly is not limited to the structure in this example. In an example, the blade assembly may include only one blade; both the first cutting portion and the second cutting portion are provided on the blade. In the direction of the rotation axis, the second cutting portion is located below, but not limited to directly below, the first cutting portion; the first cutting portion and the second cutting portion may be integrally formed or connected with other structures to form a complete blade. For example, the blade assembly may include a blade body, and the first cutting portion and the second cutting portion are respectively disposed on a plurality of fins extending from the blade body, and the plurality of fins and the blade body may be fixedly connected or integrally formed or detachably connected. 
     As shown in  FIG.  4   , the phase angle α formed by the first cutting portion  111   a  and the second cutting portion  112   a  is greater than or equal to 0 and less than 90 degrees. The phase angle α is the angle between the straight lines on which the projections of the blade edge  111   b  of the first cutting portion  111   a  and the blade edge  112   b  of the second cutting portion  112   a  in a plane perpendicular to the rotation axis  100 ′ are located. The edge  111   b  of the first cutting portion  111   a  is the front most side of the first cutting portion  111   a , that is, the side that first contacts the vegetation when the first blade  111  rotates in the rotation direction A about the rotation axis  100 ′; Likewise, the edge of the second cutting portion  112   a  is the front most side of the second cutting portion  112   a , that is, the side that first contacts the vegetation when the second blade  112  rotates in the rotation direction A about the rotation axis  100 ′. When the phase angle of the first cutting portion  111   a  and the second cutting portion  112   a  is within the above range, the first cutting portion  111   a  and the second cutting portion  112   a  as a whole have higher cutting efficiency. In an example, the phase angle α formed by the first cutting portion  111   a  and the second cutting portion  112   a  is greater than or equal to 10 degrees and less than or equal to 60 degrees. In this example, the phase angle α between the first cutting portion  111   a  and the second cutting portion  112   a  is about 20 degrees. 
     The first blade  111  includes at least one first cutting portion  111   a , and the first cutting portion  111   a  may be regarded as a continuous cutting portion formed on the first blade  111 . In an example, the first blade  111  and the second blade  112  respectively include at least two first cutting portions  111   a  and at least two second cutting portions  112   a . In this example, the first blade  111  is formed with two first cutting portion  111   a , the two first cutting portions  111   a  are respectively provided on two ends of the first blade  111 , and are both disposed on the front side of the rotation direction A, that is, the side that first contacts the vegetation when the first blade  111  rotates in the rotation direction A about the rotation axis  100 ′; the two first cutting portions  111   a  are center symmetrical about the rotation axis  100 ′. Similarly, the second blade  112  also includes at least one second cutting portion  112   a , in the present example the second blade  112  is formed with two second cutting portions  112   a , the two second cutting portions  112   a  are respectively provided on two ends of the second blade  112 , and are both located on the front side of the rotation direction A, that is, the side that first contacts the vegetation when the second blade  112  rotates in the rotation direction A about the rotation axis  100 ′; the two second cutting portions  112   a  are center symmetrical about the rotation axis  100 ′. 
     The sum of the number of the first cutting portions  111   a  formed by the first blade  111  and the number unit: piece of the second cutting portions  112   a  formed by the second blade  112  is defined as the number of cutting portions of the blade assembly  11 . In the blade assembly  11  of the present example, the ratio of the swept volume to the number of cutting portions of the blade assembly  11  is greater than or equal to 50 cm 3  and less than or equal to 4000 cm 3 . In one example, the ratio of the swept volume to the number of cutting portions of the blade assembly  11  is greater than or equal to 75 cm 3 /piece and less than or equal to 3400 cm 3 /piece. In one example, structurally discontinuous first cutting portions  111   a  are regarded as a plurality of different first cutting portions  111   a , and the number of first cutting portions  111   a  is the number of discontinuous first cutting portions  111   a  provided on the first blade  111 ; similarly, structurally discontinuous second cutting portions  112   a  are regarded as a plurality of different second cutting portions  112   a , and the number of second cutting portions  112   a  is the number of discontinuous second cutting portions  112   a  provided on the second blade  112 . In this example, the ratio of the swept volume to the number of cutting portions of the blade assembly  11  is about 1700 cm 3 /piece. The greater the number of cutting portions, the better the cutting performance of the lawn mower  100 , but the greater the number of cutting portions, the greater the swept volume requirement of the blade assembly  11 , as well as the load of the lawn mower  100 . In this example, by optimizing the structure of the blade assembly  11 , the ratio of the swept volume to the number of cutting portions of the blade assembly  11  is kept within the above-mentioned optimal range, thereby ensuring that the lawnmower  100  maintains an optimal cutting performance under a small load. 
     As shown in  FIG.  5   , the lawn mower  100  further includes a mounting assembly  16 , the mounting assembly  16  has a first mounting state in which the blade assembly  11  is mounted to the drive shaft  14  so that the blade assembly  11  rotates with the drive shaft  14  and a second mounting state in which one of the first blade  111  and the second blade  112  is removed and only the other one of the first cutting portion  111   a  and the second cutting portion  112   a  is mounted to perform the cutting function. 
     In this example, as shown in  FIGS.  5 - 8   , since the first cutting portion  111   a  and the second cutting portion  112   a  are respectively provided on the separately formed first blade  111  and second blade  112 , therefore, the mounting assembly  16  has a first mounting state in which the blade assembly  11  is mounted to the drive shaft  14  so that the blade assembly  11  rotates with the drive shaft  14  and a second mounting state in which one of the first blade  111  and the second blade  112  is removed and only the other one of the first blade  111  and the second blade  112  is mounted to perform the cutting function. That is to say, the mounting assembly  16  can mount the blade assembly  11  including the first blade  111  and the second blade  112  to the drive shaft  14  in the first mounting state, and can also mount the blade assembly  11  including only one of the first blade  111  and the second blade  112  to the drive shaft  14  in the second mounting state. Considering the diversity of usage conditions, the mounting assembly  16  in this example has multiple mounting states to provide better adaptability, allowing the user to reduce or increase the number of blades based on their specific needs without having to replace the entire mounting assembly  16  and blade assembly  11 , thereby enhancing mowing practicability. 
     In an example, the mounting assembly  16  has a first mounting state in which a first type of blade assembly including the first cutting portion and the second cutting portion is mounted to the drive shaft, and the mounting assembly also has a second mounting state in which the first type of blade assembly is removed and a second type of blade assembly including only one cutting portion is mounted to the drive shaft. Based on the structure that the first cutting portion and the second cutting portion are respectively provided on the first blade and the second blade, that is to say, the mounting assembly has a first mounting state in which a first type of blade assembly including the first blade and the second blade is mounted to the drive shaft. The mounting assembly also has a second mounting state in which the first type of blade assembly is removed and a second type of blade assembly including only one blade is mounted to the drive shaft. In other words, the mounting assembly  16  can not only independently install one or both of the first blade and the second blade, but also independently install other blades that do not belong to the first blade and the second blade. 
     In an example, the lawn mower includes a first type of blade assembly that performs the cutting function. The first type of blade assembly includes a first blade, and the first blade is formed with a first cutting portion that is configured to cut grass. The mounting assembly has a first mounting state in which the first type of blade assembly is mounted to the drive shaft so that the blade assembly rotates with the drive shaft; the mounting assembly also has a second type in which the first type of blade assembly is removed and a second type of blade assembly including two cutting portions is mounted to the drive shaft to perform the cutting function; wherein, the two cutting portions of the second type of blade assembly are respectively located on the upper and lower sides in the direction of the rotation axis. That is to say, the mounting assembly causes the lawn mower to switch from the first type of blade assembly with one cutting portion to the second type of blade assembly with two cutting portions; the two cutting portions are respectively located on the upper and lower sides in the direction of the rotation axis. In an example, the second type of blade assembly may include the first cutting portion of the first type of blade assembly, or may not include the first cutting portion of the first type of blade assembly but is otherwise formed second type of blade assembly totally different from the first type of blade assembly. If the second type of blade assembly includes the first cutting portion of the first type of blade assembly, the position of the first cutting portion relative to the drive shaft may be the same or may be changed. For example, the first type of blade assembly includes the first blade provided with the first cutting portion, the second type of blade assembly adds a second blade provided with a second cutting portion in addition to the first type of blade assembly, and the second blade is mounted to the lower side or the upper side of the first blade in the direction of the rotation axis through the mounting assembly. 
     In an example, the lawn mower includes a blade assembly and a lawn mower body. The lawn mower body includes a deck, a motor, and a battery pack. The motor is mounted to the deck, and the battery pack supplies power to the motor. The blade assembly includes a first type of blade assembly and a second type of blade assembly, and the motor drives the first type of blade assembly or the second type of blade assembly to rotate about a rotation axis; the first type of blade assembly includes a first blade, and the first blade is formed with a first cutting portion for cutting grass; the second type of blade assembly includes a first blade and a second blade, the first blade is formed with a first cutting portion for cutting grass; the second blade is formed with a second cutting portion for cutting grass; wherein, in the direction of the rotation axis, the second cutting portion is located below the first cutting portion; the body of the lawn mower can be adapted to the first type of blade assembly or the second type of blade assembly. The body of the lawn mower can be adapted to mount the second type of blade assembly after the first type of blade assembly is removed, or can be adapted to mount the first type of blade assembly when the second type of blade assembly is removed. 
     The blade assembly  11  in the present example is driven by friction. The mounting assembly  16  includes a drive member  161 ; the drive member  161  is configured to drive the blade assembly  11  to rotate about the rotation axis  100 ′; the drive member  161  is connected to the drive shaft  14  and is driven by the shaft  14  is, and the drive member  161  and the blade assembly  11  realize transmission through static friction. In one example, as shown in  FIGS.  5 - 6   , the drive member  161  is a flange, and the flange and the drive shaft  14  form a fixed connection in the radial direction, and the blade assembly  11  is in surface contact with the flange in a plane perpendicular to the rotation axis  100 ′. The mounting assembly  16  further includes a clamping assembly  162 ; the clamping assembly  162  is configured to push the blade assembly  11  along the direction of the rotation axis  100 ′ to the surface of the drive member  161 ; the clamping assembly  162  is mounted to the drive shaft  14  and forms a fixed and detachable connection with the drive shaft  14  in the direction along the rotation axis  100 ′. In an example, the drive shaft  14  and the flange form a flat fit, and the clamping assembly  162  includes a bolt  162   a  and a first washer  162   b . The flange, the blade assembly  11 , the first washer  162   b , and the bolt  162   a  form a close fit from top to bottom along the rotation axis  100 ′, wherein the flange, the blade assembly  11 , and the first washer  162   b  embrace around the drive shaft  14 , while the bolt  162   a  is inserted into the drive shaft  14  and forms a screw connection with the drive shaft  14 . 
     As shown in  FIG.  5   , when the mounting assembly  16  is in the first mounting state, the bottom surface of the drive member  161  is in close contact with the upper surface of the blade assembly  11 . The first washer  162   b  and the drive shaft  14  also form a flat fit. 
     As shown in  FIGS.  7 - 8   , the mounting assembly  16  is in the second mounting state. In  FIG.  7   , only the first blade  111  is mounted to the drive shaft  14  through the mounting assembly  16 . In this example, a second washer  162   c  is added to fix the position of the first blade  111  relative to the drive shaft  14  along the direction of the rotation axis  100 ′. As shown in  FIG.  8   , the mounting assembly  16  also includes a fan  15 ; the fan  15  is fixedly connected to the drive member  161  and embraces around the outside of the drive member  16 , forming a coaxial connection with the drive member  161 . The fan  15  is driven by the drive member  161 , and the drive member  161  is formed with a drive portion  161   a  as shown in  FIG.  5    for driving the fan  15 , the drive portion  161   a  protrudes from the drive member  161  in the radial direction, and the fan  15  has a groove to tightly engage with the drive portion  161   a . In the direction of the rotation axis  100 ′, the lower surface of the fan  15  is located below the lower surface of the drive member  161 . When only the first blade  111  or the second blade  112  is mounted to the drive shaft  14 , the fan  15  makes surface contact with the blade assembly  11 , the lower surface of the fan  15  pushes against the upper surface of the blade assembly  11 , and the fan  15  and the blade assembly  11  form a friction drive. In an example, the connection between the mounting assembly  16  and the blade assembly  11  can adopt both connection methods in the above two examples at the same time, that is, the mounting assembly  16  presses the first blade  111  or the second blade  112  through the clamping assembly  162 , and the clamping assembly  162  includes the fan  15  and the second washer  162   c.    
     In an example, the structure of the mounting assembly  16  and the connection method between the mounting assembly  16  and blade assembly  11  are not limited to the above examples, e.g., when the mounting assembly  16  is in the second mounting state, replace the first washer  162   b  with a second washer  162   c  that is thicker than the first washer  162   b . Simple adjustments or replacements made on the basis of the mounting assembly  16  of the present application for switching the mounting state should be considered within the scope of protection of the present application. The mounting assembly  16  may include a plurality of part or components; the mounting assembly  16  may include different sets of parts or components when the mounting assembly  16  is in the first mounting state and the second mounting state, respectively. 
     The drive member  161  and the blade assembly  11  make surface contact in a plane perpendicular to the rotation axis  100 ′; the contact area of the drive member  161  and the blade assembly  11  is greater than or equal to 100 mm 2  and less than or equal to 1000 mm 2 . In an example, the contact area of the drive member  161  and the blade assembly  11  is greater than or equal to 300 mm 2  and less than or equal to 500 mm 2 . In this example, the contact area between the flange and the blade assembly  11  is approximately 432 mm 2 , and the contact area between the lower surface of the flange and the upper surface of the blade assembly  11  is approximately 432 mm 2 . Correspondingly, when the mounting assembly  16  is in the second mounting state and the fan  15  and the blade assembly  11  form a friction drive, the fan  15  and the blade assembly  11  make surface contact in a plane perpendicular to the rotation axis  100 ′; the contact area between the fan  15  and the blade assembly  11  is greater than or equal to 100 mm 2  and less than or equal to 1000 mm 2 . 
     As shown in  FIGS.  4 - 6    and  FIG.  9   , the blade assembly  11  is formed with at least one mounting hole  113  that engages with the drive shaft  14 . In this example, when the blade assembly  11  forms an integral unit that moves together, the blade assembly  11  only has a mounting hole  113  that engages with the drive shaft  14  to facilitate user installation. The mounting hole  113  is located approximately at the center of the blade assembly  11 , and the blade assembly  11  is center symmetrical about the center of the mounting hole  113 , making the blade assembly  11  more stable when rotating about the rotation axis  100 ′, and avoiding the generation of eccentric torques. In an example, the first blade  111  and the second blade  112  are respectively formed with a first mounting hole  113   a  and a second mounting hole  113   b . When the blade assembly  11  is mounted to the drive shaft  14 , the first mounting hole  113   a  and the second mounting holes  113   b  overlap in the up-down direction along the rotation axis  100 ′. In an example, the blade assembly  11  may be formed with a plurality of mounting holes  113 , and the mounting assembly  16  includes a plurality of connecting shafts that engage with the mounting holes  113  accordingly, and the connecting shafts are connected to the drive shaft  14 . 
     As shown in  FIG.  5   , the mounting assembly  16  is in contact with the blade assembly  11  to form at least one mounting surface  16   a  that is substantially perpendicular to the rotation axis  100 ′; the blade assembly  11  is formed with at least one cutting surface  11   a  that is perpendicular to the rotation axis  100 ′; at least one mounting surface  16   a  is located above the cutting surface  11   a  in the direction of the rotation axis  100 ′. In this example, the flange of the mounting assembly  16  or the fan  15  and the first washer  162   b  make surface contact with the blade assembly  11  and form two mounting surfaces  16   a  perpendicular to the rotation axis  100 ′. When the blade assembly  11  includes the first blade  111  or the second blade  112 , the first blade  111  or the second blade  112  rotates about the rotation axis  100 ′ to form a cutting surface  11   a , the plane where the cutting surface  11   a  is located is the plane where the edge  111   b  of the first cutting portion  111   a  or the edge  112   b  of the second cutting portion  112   a  is located. When the blade assembly  11  includes the first blade  111  and the second blade  112 , the first blade  111  and the second blade  112  rotate about the rotation axis  100 ′ to form two parallel upper and lower cutting surfaces  11   a , and the plane where the two upper and lower cutting surfaces  11   a  are located are the planes where the edge  111   b  of the first cutting portion  111   a  and the edge  112   b  of the second cutting portion  112   a  are respectively located. In this example, one mounting surface  16   a  is located above the two cutting surfaces  11   a  along the direction of the rotation axis  100 ′ to avoid installing the mounting assembly  16  below the cutting surface  11   a . In this example, the drive member  161  that drives the blade assembly  11  to rotate is located above the cutting surface  11   a.    
     As shown in  FIG.  9   , the blade assembly  11  further includes a connecting assembly  114 . The connecting assembly  114  connects the second blade  112  to the first blade  111  so that the blade assembly  11  forms a unit that can move together when not mounted to the drive shaft  14 . After the connecting assembly  114  connects the second blade  112  to the first blade  111 , the second cutting portion  112   a  and the first cutting portion  111   a  are located at different axial positions along the rotation axis  100 ′. That is to say, when the first blade  111  and the second blade  112  are not integrally formed, the first blade  111  and the second blade  112  are connected as a whole through the connecting assembly  114 , and when not mounted to the drive shaft  14 , the first blade  111  and the second blade  112  may be fixedly connected or movably connected, that is, the first blade  111  may move relative to the second blade  112 . When the blade assembly  11  is mounted to the drive shaft  14  and performs cutting as a whole, the first blade  111  is fixed relative to the second blade  112 . At the same time, the connecting assembly  114  determines the relative position of the first cutting portion  111   a  and the second cutting portion  112   a  in the direction of the rotation axis  100 ′. In an example, the first cutting portion  111   a  is located above the second cutting portion  112   a . In this example, the first blade  111  is located above the second blade  112 . The connecting assembly  114  enables the user to disassemble and assemble the blade assembly  11  for ease of operation, while at the same time, fixes the relative axial positions of the first cutting portion  111   a  and the second cutting portion  112   a  to prevent the user from repositioning the two cutting portions axially during assembly and installing the first blade  111  and the second blade  112  reversely or incorrectly, which plays a foolproof role. 
     When the connecting assembly  114  connects the second blade  112  to the first blade  111 , the second blade  112  is fixed within a predetermined angle range relative to the first blade  111 . In an example, the predetermined angle range is greater than or equal to 0 degrees and less than or equal to 20 degrees. In this example, the predetermined angle range is greater than or equal to 5 degrees and less than or equal to 10 degrees. That is to say, the connecting assembly  114  connects the first blade  111  and the second blade  112  so that the first blade  111  and the second blade  112  form a fixed connection or a movable connection in the rotation axial direction, and when the first blade  111  and the second blade  112  form a movable connection in the axial direction, the first blade  111  can rotate relative to the second blade  112  with a rotation angle greater than or equal to 0 degrees and less than or equal to 10 degrees. The first blade  111  and the second blade  112  form a detachable connection through the connecting assembly  114  for ease of maintenance or replacement of the blade assembly  11  later. 
     In this example, the connecting assembly  114  is a common fastener, such as a bolt and a nut or a screw and a nut. The blade assembly  11  is formed with at least one positioning portion  115  connected to the connecting assembly  114 ; the positioning portion  115  can define the range of the phase angle of the first blade  111  relative to the second blade  112 , and the connecting assembly  114  is mounted to the positioning portion  115 . In this example, the positioning portion  115  is a positioning hole, and positioning holes are formed on both the first blade  111  and the second blade  112 . The number of positioning portions  115  is not limited. In this example, the number of positioning portions  115  is greater than or equal to two. In an example, the first blade  111  is formed with two diamond holes symmetrical about the rotation axis  100 ′, and the second blade  112  is formed with two round holes symmetrical about the rotation axis  100 ′, the diamond holes engage with the diamond-shaped protrusions on the head of the bolts, the round holes engage with the studs of the bolts, and the bolts are locked with the nuts, so that the first blade  111  and the second blade  112  are fixedly connected with a fixed phase angle in the circumferential direction and a fixed relative position in the axial direction. In an example, the positioning hole may also be square or waist or other shaped; the engagement manner between the positioning hole on the first blade  111  and the positioning hole on the second blade  112  and the connecting assembly  114  is not limited herein. 
     The connecting assembly  114  includes an engaging portion  114   a  that engages with the positioning portion  115 . In this example, the positioning portion  115  is a positioning hole, the engaging portion  114   a  is a bolt, and is a screw of the bolt, which engage with the positioning hole to form a shaft hole fit. The connecting assembly  114  further includes an axial fixing portion that fixes the position of the first blade  111  relative to the second blade  112  in a direction parallel to the rotation axis  100 ′, and the axial fixing portion is a bolt and nut. In an example, the axial fixing portion may be a magnetic element mounted to the first blade  111  and the second blade  112 , and the axial position of the first blade  111  relative to the second blade  112  is fixed by magnetic attraction. The specific structures of the engaging portion  114   a  and the axial fixing portion are not limited to the above. 
     In an example, the engaging portion of the connecting assembly is provided on a mounting member such as a fan or a flange, and forms a fixed connection or is integrally formed with the mounting member such as a fan and a flange. For example, a drive portion is formed at the lower end of the fan, and the drive portion is configured to mount and position the blade assembly. In one example, the connecting assembly further includes a clamping member that axially clamps the blade assembly, and the clamping member is connected to the blade assembly and makes surface contact with the blade assembly. In this case, the blade assembly can form either a friction transmission or a mechanical position transmission such as a flat position transmission with the drive shaft. 
     As shown in  FIGS.  4 ,  5 , and  10   , the positioning portion  115  generally has a geometric center. The distance from the geometric center to the rotation axis  100 ′ is the positioning radius r, and the positioning radius r is greater than or equal to 0 mm and less than or equal to 50 mm. In one example, the positioning radius r of the positioning portion  115  is greater than or equal to the radius of the drive shaft  14  and less than or equal to 50 mm; in this example, the positioning radius r of the positioning portion  115  is about 30 mm. When the positioning radius r of the positioning portion  115  is 0 mm, that is, the geometric center of the positioning portion  115  coincides with the rotation axis  100 ′. In one example, a radial groove is formed on the drive shaft  14 , and the groove can accommodate the positioning portion  115 . The positioning portion  115  is provided outside the drive shaft  14 , that is, the positioning radius r of the positioning portion  115  is greater than or equal to the radius of the drive shaft  14 . For a regularly shaped positioning portion  115 , the geometric center is uniquely determined; for an irregularly shaped positioning portion  115 , a point at the center of the positioning portion  115  may be roughly determined to be the geometric center. In one example, the ratio of the rotation diameter D of the blade assembly  11  to the positioning radius r of the positioning portion  115  is greater than or equal to 5 and less than or equal to 25. When the position of the positioning unit  115  is in the above range, the positioning effect of the positioning unit  115  is better. The rotation diameter D is greater than or equal to 200 mm and less than or equal to 700 mm. 
     In an example, the positioning hole may be other positioning holes with incomplete positioning effects, such as oval holes. These positioning holes can restrict to a predetermined degree but cannot completely restrict the rotation of the first blade  111  relative to the second blade  112 , such that the blade assembly  11  has a predetermined adjustment space when encountering obstacles, thereby enhancing the service life of the blade assembly  11 . 
     The maximum length of the line connecting any two points of the projection of the first blade  111  in a plane perpendicular to the rotation axis  100 ′ in the direction perpendicular to the rotation diameter D 1  of the first blade  111  is the width W 1  of the first blade  111 . The ratio of the rotation diameter D 1  of the first blade  111  to the width W 1  of the first blade  111  is equal to or greater than 5 and less than or equal to 13. The maximum length of the line connecting any two points of the projection of the second blade  112  in a plane perpendicular to the rotation axis  100 ′ in the direction perpendicular to the rotation diameter D 2  of the second blade  112  is the width W 2  of the second blade  112 . The ratio of the rotation diameter D 2  of the second blade  112  to the width W 2  of the second blade  112  is equal to or greater than 5 and less than or equal to 13. In this example, the rotation diameter D 1  of the first blade  111  is approximately 511 mm, the width W 1  of the first blade  111  is approximately 51 mm, and the rotation diameter D 2  of the second blade  112  is approximately equal to the rotation diameter D 1  of the first blade  111 . The width W 2  of the second blade  112  is approximately equal to the width W 1  of the first blade  111 . 
     As shown in  FIGS.  9  and  10   , at least one reinforcement rib  116  is respectively formed on the surfaces of the first blade  111  and the second blade  112 . In this example, the first blade  111  and the second blade  112  are respectively formed with two reinforcement ribs  116 . The two reinforcement ribs  116  on the surface of the first blade  111  protrude upward and extend along the length of the first cutting portion  111   a , and are symmetrical about the rotation axis  100 ′; the two reinforcement ribs  116  on the surface of the second blade  112  protrude downward and extend along the length of the second cutting portion  112   a , and are symmetrical about the rotation axis  100 ′. The shape of the reinforcement rib  116  is a long stripe. The ratio of the rotation diameter D 1  of the first blade  111  to the length al of a single reinforcement rib  116  is greater than or equal to 2.5 and less than or equal to 10; the ratio of the rotation diameter D 1  of the first blade  111  to the total length of the plurality of the reinforcement ribs  116  is greater than or equal to 1.3 and less than or equal to 5; the ratio of the width W 1  of the first blade  111  to the width b 1  of a single reinforcement rib  116  is greater than or equal to 2 and less than or equal to 5. Similarly, the ratio of the rotation diameter D 2  of the second blade  112  to the length al of a single reinforcement rib  116  is greater than or equal to 2.5 and less than or equal to 10; the ratio of the rotation diameter D 2  of the second blade  112  to the total length of the plurality of the reinforcement ribs  116  is greater than or equal to 1.3 and less than or equal to 5; the ratio of the width W 2  of the second blade  112  to the width b 1  of a single reinforcement rib  116  is greater than or equal to 2 and less than or equal to 5. In one example, the length al of the reinforcement rib  116  refers to the maximum dimension of the projection of the reinforcement rib  116  in a plane perpendicular to the rotation axis  100 ′ in the extending direction of the reinforcement rib  116 ; the width b 1  of the reinforcement rib  116  refers to the maximum dimension of the projection of the reinforcement rib  116  in a plane perpendicular to the rotation axis  100 ′ in the direction perpendicular to the extending direction of the reinforcement rib  116 . In the extending direction of the first blade  111  or the second blade  112  and in the direction perpendicular to the extending direction of the first blade  111  or the second blade  112 , the reinforcement ribs  116  are distributed in the middle of the first blade  111  and the second blade  112  to improve the strength of the first blade  111  or the second blade  112 . In other examples, the number, position, and specific shape of the reinforcement rib  116  are not limited thereto. 
     In this example, the first blade  111  substantially extends along the direction of the first straight line; the second blade  112  substantially extends along the direction of the first curve. Since the first blade  111  is disposed above the second blade  112  in the direction of the rotation axis  100 ′, and at the same time the first curve is at least partially curved downward, a sufficient accommodation space is formed between the first blade  111  and the second blade  112 . In an example, the first blade  111  extends substantially in the direction of the second curve; the second blade  112  extends substantially in the direction of the third curve, that is, the first blade  111  and the second blade  112  extend along the curve respectively. The second curve and the third curve are two different curves differing in at least part of their curvatures, so that a sufficient accommodation space is formed between the first blade  111  and the second blade  112 . 
     The length of the projection of the first cutting portion  111   a  in a plane perpendicular to the rotation axis  100 ′ is greater than or equal to 10 mm and less than or equal to 600 mm; the length of the projection of the second cutting portion  112   a  in a plane perpendicular to the rotation axis  100 ′ is greater than or equal to 10 mm and less than or equal to 600 mm. In an example, the length of the projection of the first cutting portion  111   a  in a plane perpendicular to the rotation axis  100 ′ refers to the length of the projection of the edge  111   b  of the first cutting portion  111   a  in a plane perpendicular to the rotation axis  100 ′. When the first blade  111  includes a plurality of the first cutting portions  111   a , the length of the projection of the first cutting portion  111   a  in a plane perpendicular to the rotation axis  100 ′ is the sum of the length of the projection of the edges  111   b  of the plurality of the first cutting portions  111   a  in a plane perpendicular to the axis  100 ′. Similarly, the length of the projection of the second cutting portion  112   a  in a plane perpendicular to the rotation axis  100 ′ refers to the length of the projection of the edge  112   b  of the second cutting portion  112   a  in a plane perpendicular to the rotation axis  100 ′. When the second blade  112  includes a plurality of the second cutting portions  112   a , the length of the projection of the second cutting portion  112   a  in a plane perpendicular to the rotation axis  100 ′ is the sum of the length of the projection of the edges  112   b  of the plurality of the second cutting portions  1112   a  in a plane perpendicular to the rotation axis  100 ′. Both the length of the projection of the first cutting portion  111   a  in a plane perpendicular to the rotation axis  100 ′ and the length of the projection of the second cutting portion  112   a  in a plane perpendicular to the rotation axis  100 ′ are greater than or equal to 10 mm and less than or equal to 600 mm. In an example, the length of the projection of the first cutting portion  111   a  in a plane perpendicular to the rotation axis  100 ′ and the length of the projection of the second cutting portion  112   a  in a plane perpendicular to the rotation axis  100 ′ are greater than or equal to 20 mm and less than or equal to 400 mm. In this example, the length of the projection of the first cutting portion  111   a  in a plane perpendicular to the rotation axis  100 ′ is about 236 mm. In one example, the length of the projection of the first cutting portion  111   a  in a plane perpendicular to the rotation axis  100 ′ and the length of the projection of the second cutting portion  112   a  in a plane perpendicular to the rotation axis  100 ′ are substantially equal. 
     The mass of the blade assembly  11  is greater than or equal to 0.35 kg and less than or equal to 1.8 kg. When the mass of the blade assembly  11  is within this value range, the lawn mower  100  has a relatively small load and relatively high work efficiency. When the first blade  111  and the second blade  112  is separately formed and the mass of the first blade  111  is less than or equal to the mass of the second blade  112 , the ratio of the mass of the first blade  111  to the mass of the second blade  112  is greater than or equal to 0.5 and less than or equal to 1. In an example, when the first blade  111  and the second blade  112  are separately formed and the mass of the second blade  112  is less than or equal to the mass of the first blade  111 , the ratio of the mass of the second blade  112  to the mass of the first blade  111  is greater than or equal to 0.5 and less than or equal to 1. 
     The battery pack includes a battery pack housing and battery cells. The battery cells are disposed in the battery pack housing. The number of battery cells included in the battery pack is N and the unit is piece. The mass of the blade assembly  11  is M and the unit is kilogram. The maximum length of a line connecting any two points of the projection of the blade assembly  11  in a plane perpendicular to the rotation axis  100 ′ and the projection of the rotation axis  100 ′ in the plane is the rotation diameter D of the blade assembly  11 ; and the unit is millimetre. The product of the rotation diameter D mm of the blade assembly  11 , the number of battery cells N and mass M g of the blade assembly  11  is greater than or equal to 3.5×10 5  and less than or equal to 7.3×10′. In one example, the product of the rotation diameter D mm of the blade assembly  11 , the number of battery cells N and mass M g of the blade assembly  11  is greater than or equal to 7×10 5  mm·g and less than or equal to 3.6×10 7  mm·g. In one example, the product of the rotation diameter D mm of the blade assembly  11 , the number of battery cells N and mass M g of the blade assembly  11  is greater than or equal to 1.4×10 6  mm·g and less than or equal to 1.8×10 7  mm·g. When the product of the rotation diameter D mm of the blade assembly  11 , the number of battery cells N and mass M g of the blade assembly  11  is in the above numerical range, the lawn mower  100  has a relatively small load and relatively high work efficiency. In this example, the mass M of the blade assembly  11  refers to the total mass of the blade assembly  11  including the first blade  111  and the second blade  112 . When the lawn mower  100  includes multiple battery packs, the number N of battery cells here refers to the total number of battery cells included in all battery packs. In this example, the rotation diameter D of the blade assembly  11  is about 508 mm, and the number N of battery cells contained in the battery pack is equal to 10. In one example, the number N of battery cells refers to the number of battery cells included in the battery pack that powers the motor  13  that drives the blade assembly  11 . If the lawn mower  100  is a self-propelled lawn mower, generally it also includes a self-propelled motor that drives the wheels to rotate. In this case, the motor  13  should not include the self-propelled motor. That is to say, the battery packs here do not include the battery pack that powers the self-propelled motor. 
     In one example, the larger value of the rotation diameter D 1  of the first blade  111  and the rotation diameter D 2  of the second blade  112  is defined as the lateral dimension of the blade assembly  11 . The battery pack contains the number N of battery cells, and the mass of the blade assembly  11  is M g. The product of the lateral dimension mm of the blade assembly  11 , the number N of battery cells, and the mass M g of the blade assembly  11  is greater than or equal to 3.5×10 5  mm·g and less than or equal to 7.3×10 7  mm·g. In one example, the product of the lateral dimension mm of the blade assembly  11 , the number N of battery cells, and the mass M g of the blade assembly  11  is greater than or equal to 7×10 5  mm·g and less than or equal to 3.6×10 7  mm·g. In one example, the product of the lateral dimension mm of the blade assembly  11 , the number N of battery cells, and the mass M g of the blade assembly  11  is greater than or equal to 1.4×10 6  mm·g and less than or equal to 1.8×10 7  mm·g. 
     The output torque of the motor  13  is greater than or equal to 0 and less than or equal to 10 N·m; in one example, the output torque of the motor  13  is greater than or equal to 3 N·m and less than or equal to 8 N·m; in this example, the output torque of the motor  13  is about 4 N·m. When the output torque of the motor  13  is in the above numerical range, the lawn mower  100  has higher cutting efficiency or cutting capacity. 
     In this example, the rotational inertia of the blade assembly  11  is greater than or equal to 8000 kg·mm 2  and less than or equal to 23000 kg·mm 2 ; in one example, the rotational inertia of the blade assembly  11  is greater than or equal to 15000 kg·mm 2  and less than or equal to 20000 kg·mm 2 . 
     In addition, under certain working conditions, the lawn mower  100  not only needs to cut the vegetation, but also needs to chop up the vegetation clippings into finer pieces, or to collect the vegetation clippings into a collecting device. By adopting the structural design of the blade assembly  11  described above, the lawn mower  100  also has a better ability to chop up grass or discharge grass. The lawn mower  100  is also provided with a collecting device not shown for collecting the vegetation clippings. The collecting device is connected to the deck  12 . In an example, the deck  12  is formed with a discharge chute; the collecting device is connected to the discharge chute to let the vegetation clippings enter the collecting device from the deck  12 . When the blade assembly  11  rotates at a tip linear velocity greater than or equal to 40 m/s and less than or equal to 100 m/s, the average air velocity at the discharge chute is greater than or equal to 3 m/s and less than or equal to 25 m/s. In an example, when the blade assembly  11  rotates at a tip linear velocity greater than or equal to 40 m/s and less than or equal to 100 m/s, the average air velocity at the discharge chute is greater than or equal to 5 m/s and less than or equal to 15 m/s. When the average air velocity at the discharge chute is in the above numerical range, the grass chopping ability and the grass discharging ability of the lawn mower  100  can be improved. 
     In this example, the linear velocity of the tip of the blade assembly  11  refers to the linear velocity of the point on the blade assembly  11  with the largest distance to the axis of rotation  100 ′ when the blade assembly  11  rotates around the axis of rotation  100 ′. 
       FIG.  11    is a schematic diagram of the blade assembly  21  of the lawn mower provided in a second example of the present application mounted to the drive shaft  24 . The difference between this example and the first example is that the blade assembly  21  in this example does not include a connecting assembly, and the blade assembly  21  has a positioning portion  213  and an engaging portion  214  to define the phase angle range between the first blade  211  and the second blade  212 , whereas the remaining structure of the lawn mower of this example is the same as that of the first example. One of the first blade  211  and the second blade  212  is formed with a positioning portion  213 , and the other one is formed with the engaging portion  214  to engage with the positioning portion  213 ; when the positioning portion  213  and the engaging portion  214  engage with each other, the second blade  212  is fixed or can rotate within a predetermined angle range relative to the first blade  211  in the circumferential direction around the rotation axis  211 ′. That is to say, without the connecting assembly, the position of the second blade  212  relative to the first blade  211  in the circumferential direction around the rotation axis  211 ′ can be defined by the positioning portion  213  and the engaging portion  214  only. In this example, the first blade  211  and the second blade  212  are respectively provided with the engaging portion  214  and a positioning portion  213 . The positioning portion  213  is a projection provided on the second blade  212  and protruding above the upper surface of the second blade  212 ; the engaging portion  214  is a through hole provided on the first blade  211 . When the first blade  211  and the second blade  212  are mounted to the drive shaft  24 , the projection passes through the through hole and engages with the through hole, thereby achieving the positioning of the first blade  211  relative to the second blade  212  in the circumferential direction around the rotation axis  211 ′. The positioning portion  213  may be a regular three-dimensional structure such as a cylindrical shape or other irregular shapes. The engaging portion  214  may be a through hole with a circular cross section or other through holes that can engage with the positioning portion  213 . 
     In an example, the specific structures of the positioning portion  213  and the engaging portion  214  are not limited to the above projections and through holes. For example, the positioning portion  213  may be a projection protruding from the second blade  212 , and the engaging portion  214  may be an accommodating portion protruding upward on the surface of the first blade  211 ; the accommodating portion can accommodate at least part of the positioning portion  213  or engage with the positioning portion  213 , so as to realize the positioning of the first blade  211  relative to the second blade  212 . 
     The number of the positioning portion  213  and the engaging portion  214  is not limited. In an example, the number of the positioning portion  213  and the engaging portion  214  are even and the positioning portion  213  and the engaging portion  214  are respectively arranged symmetrically about the rotation axis  211 ′ to put uniform force on the first blade  211  and the second blade  212 , so that the position of the first blade  211  relative to the second blade  212  is more stable. 
     Similar to the first example, the positioning portion  213  according to the present example generally has a geometric center; the distance from this geometric center to the rotation axis  211 ′ is the positioning radius r′; the radius r′ of the positioning portion  213  is greater than or equal to 0 mm and less than or equal to 50 mm. In one example, the positioning radius r′ of the positioning portion  213  is greater than or equal to the radius of the drive shaft  24  and less than or equal to 50 mm; in this example, the positioning radius r′ of the positioning portion  213  is about 30 mm. When the positioning radius r′ is 0 mm, that is, the geometric center of the positioning portion  213  coincide with the rotation axis  211 ′. In one example, a radial groove is made on the drive shaft  24  to accommodate the positioning portion  213 . The positioning portion  213  is provided outside the drive shaft  24 , that is, the positioning radius r′ of the positioning portion  213  is greater than or equal to the radius of the drive shaft  24 . For a regularly shaped positioning portion  213 , the geometric center is uniquely determined; for an irregularly shaped positioning portion  213 , a point at the center of the positioning portion  213  may be roughly determined to be the geometric center. The maximum length of a line connecting any two points of the projection of the blade assembly  21  in a plane perpendicular to the rotation axis  211 ′ and the projection of the rotation axis  211 ′ in the plane is the rotation diameter of the blade assembly  21 . The rotation diameter is greater than or equal to 200 mm and less than or equal to 700 mm. In one example, the rotation diameter is greater than or equal to 250 mm and less than or equal to 560 mm. In an example, the ratio of the rotation diameter of the blade assembly  21  to the positioning radius r′ of the positioning portion  213  is greater than or equal to 5 and less than or equal to 25. When the position of the positioning portion  213  is within the above range, the positioning effect of the positioning portion  213  is better. Correspondingly, the engaging portion  214  also has a geometric center, and the distance from the geometric center to the rotation axis  211 ′ is the positioning radius of the engaging portion  214 ; the positioning radius of the engaging portion  214  is greater than or equal to 0 and less than or equal to 50 mm; in one example, the positioning radius of the engaging portion  214  is greater than or equal to the radius of the drive shaft  24  and less than or equal to 50 mm. 
       FIG.  12    is a schematic diagram of a blade assembly and a connection assembly of a lawn mower provided in a third example of the present application. The difference from the first example and the second example lies in the structure of the connecting assembly and the connection method between the connecting assembly and the blade assembly, whereas other similarities can be applied to this example. The lawn mower includes a connecting assembly  312 ; the connecting assembly  312  is formed with a first connection portion  312   a  that connects the first blade  311  and a second connection portion  312   b  that connects the second blade  313 ; the second blade  313 , relative to the first blade  311 , is fixed or can rotate within a predetermined angle range in the circumferential direction around the rotation axis  311 ′. That is to say, the first blade  311  and the second blade  313  are fixed or can rotate within a predetermined angle range in the circumferential direction around the rotation axis  311 ′ through the connecting assembly  312 , and the first blade  311  and the second blade  313  themselves do not constitute a connection. In this example, the connecting assembly  312  is a flange, but it is not limited to a flange. The connecting assembly  312  forms a fixed connection with the first blade  311  and the second blade  313  respectively in the up-down direction to make the first blade  311  and the second blade  313  construct a fixed phase angle. The connection of the connecting assembly  312  to the first blade  311  and the second blade  313  may also be movable, so that the second blade  313  can rotate within a predetermined angle range relative to the first blade  311  in the circumferential direction around the rotation axis  311 ′. 
       FIGS.  13 - 16    are schematic views of a blade assembly  41  of a lawnmower provided in a forth example of the present application. Similarly, the blade assembly  41  rotates about the rotation axis  411 ′. The blade assembly  41  in this example differs from the lawn mower in the first example only in the structure of the second blade  412  of the blade assembly  41 . Similarities to the first example can be applied to this example. In the direction parallel to the rotation axis  411 ′, the second cutting portion  412   a  is located below the first cutting portion  411   a ; in the circumferential direction around the rotation axis  411 ′, the first cutting portion  411   a  is provided in front of the second cutting portion  412   a ; second cutting portion  412   a  is disposed on the front edge of the second blade  412 . In an example, the front side in the circumferential direction around the rotation axis  411 ′ refers to the side that first contacts the vegetation when the blade assembly  41  rotates along the rotation axis  411 ′ in the first direction A′. The first cutting portion  411   a  contacts the vegetation prior to the second cutting portion  412   a ; and the second cutting portion  412   a  is provided on the edge of the second blade  412  that first contacts the vegetation. In this example, two first cutting portions  411   a  are respectively disposed on the front sides of both ends of the first blade  411 , and the two first cutting portions  411   a  are center symmetrical about the rotation axis  411 ′; two second cutting portions  412   a  are respectively disposed on the front sides of both ends of the second blade  412 , and the two second cutting portions  412   a  are center symmetrical about the rotation axis  411 ′, and the blade assembly  41  as a whole is also center symmetrical about the rotation axis  411 ′. 
     The rear side of the second blade  412  is also formed with a first guide portion  412   b  and a second guide portion  412   c  that guide the upward movement of the airflow, that is, the second blade  412  is formed with a first guide portion  412   b  and a second guide portion  412   c  on the side opposite to the second cutting portion  412   a  in the circumferential direction of the rotation axis  411 ′. The first guide portion  412   b  and the second guide portion  412   c  are configured to guide the air flow upward. Here, the first guide portion  412   b  and the second guide portion  412   c  refer to two at least partially separated entities. In this example, the first guide portion  412   b  and the second guide portion  412   c  are integrally formed with the second blade  412 ; the first guide portion  412   b  and the second guide portion  412   c  extend substantially along the direction perpendicular to the longitudinal direction of the second blade  412  and are sequentially arranged along the longitudinal direction of the second blade  412 . In one example, the first guide portion  412   b  and the second guide portion  412   c  may be respectively formed separately from the second blade  412  and fixedly connected to the second blade  412 . 
     Each second cutting portion  412   a  corresponds to a first guide portion  412   b  and a second guide portion  412   c . The first guide portion  412   b  and the second guide portion  412   c  are disposed at the rear side of the same end of the second cutting portion  412   a . In this example, since the second blade  412  is provided with two second cutting portions  412   a , two first guide portions  412   b  and two second guide portions  412   c  are formed, the two first guide portions  412   b  and the two second guide portions  412   c  are center symmetrical about the rotation axis  411 ′. 
     The first guide portion  412   b  is curved upward along the first curved surface, and the second guide portion  412   c  is curved upward along the second curved surface different from the first curved surface. In an example, at least part of the first guide portion  412   b  and at least part of the second guide portion  412   c  have different curvatures. The first guide portion  412   b  and the second guide portion  412   c  may each have a fixed curvature, or the curvatures of the first guide portion  412   b  and the second guide portion  412   c  may change according to a predetermined rule or change irregularly, which is not limited herein. In this example, the first guide portion  412   b  and the second guide portion  412   c  each have varying curvatures. In one example, the curvature radius at any point of the first guide portion  412   b  and the second guide portion  412   c  is equal to or greater than 0 and less than or equal to 100 mm. In this example, the curvature radius at any point of the first guide portion  412   b  and the second guide portion  412   c  is equal to or greater than 0 mm and less than or equal to 60 mm. 
     The second blade  412  includes at least a first guide portion  412   b  and a second guide portion  412   c . In this example, the second blade  412  is further provided with a third guide portion. In an example, the second blade  412  may further be provided with a plurality of guide portions such as a fourth guide portion, and the plurality of guide portions are sequentially arranged along the extension direction of the second blade  412 . 
     The first guide portion  412   b  and the second guide portion  412   c  are both curved up from the end of the second blade  412 , the portion where the first guide portion  412   b  starts to turn up is the first root portion  412   d , and the portion where the second guide portion  412   c  starts to turn up is the second root portion  412   e . The first root portion  412   d  and the second root portion  412   e  are approximately on the same straight line, and this straight line intersects the extension line of the blade edge of the second cutting portion  412   a  obliquely, and the intersection angle β formed by the straight line and the extension line of the cutting edge of the cutting portion  412   a  is greater than or equal to 0 and less than or equal to 40 degrees. In an example, the intersection angle formed by the straight line and the extension line of the cutting edge of the second cutting portion  412   a  is greater than or equal to 0 and less than or equal to 15 degrees. In this example, the intersection angle formed by the straight line and the extension line of the second cutting portion  412   a  is about 6.9 degrees. 
     The outside of the first guide portion  412   b  and the outside of the second guide portion  412   c  extend substantially along the same straight line, and the straight line obliquely intersects the extension line of the second cutting portion  412   a . The outside of the first guide portion  412   b  refers to the edge opposed to the first root  412   d , and the outside of the second guide portion  412   c  refers to the edge opposed to the second root  412   e . In this example, the extending direction of the outside of the first guide portion  412   b  and the outside of the second guide portion  412   c  is substantially parallel to the straight line where the first root portion  412   d  and the second root portion  412   e  are located. 
     In this example, a cutting portion opening is further formed on the outside of the first guide portion  412   b  and the outside of the second guide portion  412   c . The cutting portion opening can further cut vegetation and improve the grass chopping ability of the lawn mower. In an example, the cutting portion opening on the first guide portion  412   b  and the second guide portion  412   c  is not necessarily a common cutting portion structure, as long as it has predefined cutting capabilities. 
       FIG.  17    is a schematic diagram of part of the structure of the lawn mower provided in a fifth example of the present application. This example differs from the first example in the structure of the blade assembly  51  and the mounting assembly  56 , whereas similarities to the first example can be applied to this example. 
     As shown in  FIGS.  17 - 19   , the motor drives the blade assembly  51  to rotate about the rotation axis  511 ′; the blade assembly  51  includes a first cutting portion  511   a  and a second cutting portion  512   a  configured to cut vegetation; wherein in the direction parallel to the rotation axis  511 ′, the second cutting portion  512   a  is located below the first cutting portion  511   a ; in this example, the blade assembly  51  includes a first blade  511  and a second blade  512 , and the first cutting portion  511   a  is disposed on the first blade  511 , the second cutting portion  512   a  is disposed on the second blade  512 , and the first blade  511  is mounted above the second blade  512  in the direction of the rotation axis  511 ′. The mounting assembly  56  includes a drive member  561 , the drive member  561  is configured to drive the blade assembly  51  to rotate about the rotation axis  511 ′; the blade assembly  51  is detachably connected to the drive member  561 . In an example, the drive member  561  is connected to the drive shaft  54  and rotates synchronously with the drive shaft  54 . The drive member  561  and the drive shaft  54  form a fixed connection along the circumferential direction of the rotation axis  511 ′, such as a flat connection or a threaded connection. 
     In this example, the mounting assembly  56  further includes a drive portion  561   a , the drive portion  561   a  is fixedly connected to the drive member  561  or integrally moulded with the drive member  561 ; the drive portion  561   a  is connected to the blade assembly  51  so that blade assembly  51  forms a fixed connection along the circumferential direction of the rotation axis  511 ′ relative to the drive member  561  or the blade assembly  51  rotates within a predetermined angle range relative to the drive member  561  along the circumferential direction of the rotation axis  511 ′. In an example, the drive portion  561   a  is respectively connected to the first blade  511  and the second blade  512 , and drive the first blade  511  and the second blade  512  are to rotate synchronously with the drive portion  561   a . There is no limitation on the position where the drive portion  561   a  is provided and the number of drive portions  561   a . In this example, the number of drive portions  561   a  is two, and the two drive portions  561   a  are respectively disposed on two sides of the rotation axis  511 ′, and the first blade  511  and the second blade  512  are stacked together in the direction of the rotation axis  511 ′ with at least partial contact. Both of the two drive portions  561   a  are connected to the first blade  511  and the second blade  512 ; the first blade  511  and the second blade  512  are formed with positioning holes engaging with the two drive portions  561   a ; one of the drive portion  561   a  is substantially cylindrical and forms a rotational connection with the first blade  511  and the second blade  512 ; the other drive portion  561   a  forms a flat connection with the first blade  511  and the second blade  512 . In other examples, only one drive portion  561   a  may be provided; the drive portion  561   a  and the blade assembly  51  form a flat connection. Alternatively, two cylindrical drive portions  561   a  may be provided to connect to the blade assembly  51 . 
     The mounting assembly  56  further includes a clamping assembly  562  and a fastening assembly  563 ; the clamping assembly  562  is configured to clamp the blade assembly  51  along the rotation axis  511 ′, and the blade assembly  51  is disposed between the drive member  561  and the clamping assembly  562  in a direction parallel to the rotation axis  511 ′; the fastening assembly  563  is set to fix the position of the blade assembly  51  relative to the drive member  561  in the direction parallel to the rotation axis  511 ; the fastening assembly  563  is removably connected to the drive shaft  54 . In this example, the clamping assembly  562  may be one or more metal shims and is at least partially in contact with the blade assembly  51 ; the fastening assembly  563  may be a nut, screw, or bolt, etc. The fastening assembly  563  is connected to the drive shaft  54  and pushes against the clamping assembly  562 . In this example, the drive shaft  54  passes through the blade assembly  51  and the clamping assembly  562 ; the fastening assembly  563  and the drive shaft  54  form a threaded connection. In an example, when the fastening assembly  563  includes a bolt or a screw, etc., there may be a fastening assembly  563  passing through at least one of the blade assembly  51  and the clamping assembly  562 . The fastening assembly  563  and the drive shaft  54  form a fixed and detachable connection. 
     The mounting assembly  56  further includes an insulating member  564 ; the insulating member  564  is configured to achieve the insulation between the blade assembly  51  and the drive shaft  54 ; the insulating member  564  is made of insulating materials; the insulating member  564  is provided between the clamping unit  562  and the blade assembly  51  in the direction of the rotation axis  511 ′; the first blade  511  and the second blade  512  are both disposed between the drive member  561  and the insulating member  564 . In this example, the insulating member  564  is in surface contact with the blade assembly  51  and the clamping assembly  562 . A groove  564   a  is formed at the bottom of the insulating member  564  in the direction of the rotation axis  511 ′, and the clamping assembly  562  is embedded in the groove  564   a . The drive shaft  54  or the fastening assembly  563  passes through the insulating member  564 . 
     In this example, the lawn mower does not include a connecting assembly that connects the first blade  511  and the second blade  512  as a whole before installation. That is to say, the first blade  511  and the second blade  512  are two independently formed and independently mounted blades, which are respectively mounted to the drive shaft  54  and constituted by the mounting assembly  56 . In this example, the blade assembly  51  is connected through the drive portion  561   a  so that the phase angle between the first blade  511  and the second blade  512  is substantially unchanged. 
       FIG.  20    is a schematic diagram of a part of the structure of the lawn mower provided in a sixth example of the present application. The difference between this example and the fifth example is the structure of the mounting assembly  66 , whereas the similarities to the fifth example can be applied to this example. 
     As shown in  FIGS.  20 - 22   , the mounting assembly  66  in this example differs from the mounting assembly  56  in the fifth example in the structure of the insulating member  664 . In this example, in the direction of the rotation axis  611 ′, two grooves, an upper groove  664   a  and a lower groove  664   b , are provided above and below the insulating member  664 ; and the first blade  611  and the second blade  612  are provided in the upper groove  664   a ; the clamping assembly  662  is disposed in the lower groove  664   b . The shape of the upper groove  664   a  fits the blade assembly  61  so that the first blade  611  and the second blade  612  form a predetermined phase angle along the rotation axis  611 ′. As in the fifth example, the drive member  661  is provided with a drive portion  661   a  referring to  FIG.  20   . In this example, the design of the insulating member  664  not only better realizes the insulation between the blade assembly  61  and the drive shaft, but also helps the blade assembly  61  maintain a fixed phase angle to prevent slippage; at the same time, it is beneficial for the drive member  661  to drive the blade assembly  61  more efficiently. 
       FIG.  23    is a schematic diagram showing a part of the structure of the lawn mower provided in a seventh example of the present application. The difference between this example and the sixth example lies in the structure of the mounting assembly  76 ; similarities to the sixth example can be applied to this example. 
     As shown in  FIGS.  23 - 25   , the mounting assembly  76  in this example differs from the mounting assembly  66  in the sixth example in the structure of the drive member  761  and the insulating member  764 . In this example, the drive member  761  drives the blade assembly  71  by friction. The drive member  761  and the blade assembly  71  form at least partial contact through the clamping assembly and the fastening assembly. In this example, the drive member  761  and the blade assembly  71  are in surface contact and are pressed against each other, and a positive pressure in the direction of the rotation axis  701  is formed between the drive member  761  and the blade assembly  71 . When the drive shaft drives the drive member  761  to rotate about the rotation axis  701 , the blade assembly  71  rotates about the rotation axis  701  under the frictional force along the circumferential direction of the rotation axis  701 . That is to say, there is no need to provide a drive portion for driving the blade assembly  71  on the drive member  761 , and there is no need to provide a positioning hole on the blade assembly  71  to engage with the drive portion. The drive member  761  drives the first blade  711  by friction, and the first blade  711  drives the second blade  712  by driving the insulating member  764 . The insulating member  764  is disposed between the first blade  711  and the second blade  712 ; the insulating member  764  is also formed with an upper groove  764   a  and a lower groove  764   b ; the first blade  711  is disposed in the upper groove  764   a , and the second blade  712  is disposed in the lower groove  764   b . That is to say, the first blade  711  is disposed between the drive member  761  and the insulating member  764 ; the second blade  712  is disposed between the insulating member  764  and the clamping assembly  762 . In an example, the upper groove  764   a  and the lower groove  764   b  are fitted to the edges of the first blade  711  and the second blade  712  respectively to make the first blade  711  and the second blade  712  to form a phase angle of the predetermined range. The clamping assembly  762  is pressed to the second blade  712 . In this example, the clamping assembly  762  is attached to the lower surface of the second blade  712 . 
       FIG.  26    is a schematic diagram of a part of the structure of the lawn mower provided in an eighth of the present application. This example differs from the fifth example in the structure of the blade assembly  81  and the mounting assembly  86 . Similarities to the fifth example can be applied to this example. The blade assembly  81  includes at least two separately formed first blades  811  and an integrally formed second blade  812 . In this example, the number of first blades  811  is two and each of the first blades  811  is provided a first cutting portion  811   a ; the second blade  812  is provided with a second cutting portion  812   a . In the direction of the rotation axis  801 , the first blades  811  are located above the second blade  812 . The two first blades  811  are respectively located on both sides of the rotation axis  801  and are fixedly connected to the second blade  812 . In an example, the first blade  811  is detachably connected to the second blade  812 . In other examples, the first blade  811  is an integrally formed blade, and the second blade  812  is a plurality of separately formed blades, each being fixedly connected to the first blade  811 . A first cutting portion  811   a  and a second cutting portion  812   a  are respectively provided on the first blade  811  and the second blade  812 . In an example, the first blade  811  and the second blade  812  are integrally formed, but the first cutting portion  811   a  and the second cutting portion  812   a  are respectively provided on the first blade  811  and the second blade  812 . That is to say, the blade assembly  81  is a one-piece blade, but is provided with a plurality of first cutting portions  811   a  and second cutting portions  812   a  distributed up and down along the direction of the rotation axis  801 . 
     In this example, the drive member  861  is provided with a drive portion, and the blade assembly  81  is provided with a positioning hole that engages with the drive portion. The drive portion  861  drives the blade assembly  81  to rotate through the drive portion. In an example, the drive portion is connected to the first blade  811 . The shape and number of drive portion is not limited. In one example, the drive member  861  is not provided with a drive portion; instead, the drive member  861  is pressed to the blade assembly  81  and drives the blade assembly  81  to rotate about the rotation axis  801  by friction. 
       FIG.  27    is a schematic diagram of a lawn mower  100  connected with a grass pressing assembly  20  according to the ninth example, wherein the lawn mower  100  according to the present example is the same as the lawn mower of the first example, except that only the lawn mower  100  in this example is connected with a grass pressing assembly  20 . The lawn mower  100  includes a blade assembly  11  and a deck  12 . The blade assembly  11  is configured to perform the cutting function of the lawn mower  100 ; the deck  12  is formed with an accommodation space for accommodating at least part of the blade assembly  11 . In this example, the blade assembly  11  is totally located inside the accommodation space. The lawn mower  100  has a travelling direction  101 ′ when travelling along a straight line on the ground. In this example, the travelling direction  101 ′ is parallel to the front-rear direction. All “assembly” in this application refer to a combination including at least one component or part, which realizes a specific function through interaction or coordination. The lawn mower  100  in the present application may be either a hand-push lawn mower or a riding lawn mower. For the convenience of explaining the technical solution of the present application, the up-down direction and the front-rear direction are defined as shown in  FIG.  27   . 
     As shown in  FIGS.  27 - 30   , the grass pressing assembly  20  is connected to the lawn mower  100 . In one example, the grass pressing assembly  20  is detachably connected to the rear end of the lawn mower  100 . The grass pressing assembly  20  is configured to compact the lawn, and the grass pressing assembly  20  serves as an accessory for the user to selectively assemble according to specific needs. The lawn mower  100  includes a mounting shaft  17 ; the mounting shaft  17  is perpendicular to the travelling direction  101 ′; the grass pressing assembly  20  is rotatably connected to the mounting shaft  17  so that the grass pressing assembly  20  can rotate about the mounting shaft  17 . The mounting shaft  17  here may be a shaft body of the lawn mower  100 , or may be a wheel shaft of the wheels, or may be another shaft body. That is to say, the grass pressing assembly  20  can be detachably connected to the mounting shaft  17 , and there is no need to add another installation structure for mounting the grass pressing assembly  20  to the lawn mower  100 , bringing the advantage of convenient installation. For any type of lawn mower  100 , as long as it has an existing shaft body, the grass pressing assembly  20  in this example can be installed on the lawn mower  100 , which has the advantage of strong adaptability. 
     As shown in  FIG.  28   , the grass pressing assembly  20  includes a drum  201 , a connecting portion  202 , and a supporting portion  203 . Wherein, the drum  201  has a predetermined weight so that the drum  201  always applies pressure to the ground, and the pressure is large enough to compact the lawn. That is to say, the grass pressing assembly  20  in this example mainly applies pressure to the lawn by the weight of the drum  201 . The connecting portion  202  and the mounting shaft  17  form a rotatable connection, that is, the connecting portion  202  can rotate about the mounting shaft  17 . In this example, the connecting portion  202  is generally hook-shaped with openings in the circumferential direction. After the connecting portion  202  is hooked to the mounting shaft  17 , the connecting portion  202  is sealed in the circumferential direction by fasteners such as screws or bolts so that the mounting shaft  17  cannot be separated from the connecting portion  202  in the radial direction. 
     As shown in  FIG.  29   , the supporting portion  203  connects the drum  201  and the connecting portion  202 . The supporting portion  203  and the connecting portion  201  may be formed integrally or separately. The supporting portion  203  includes a first support arm  2031  and a second support arm  2032 . The drum  201  has a length direction. The first support arm  2031  and the second support arm  2032  extend at least partially along the direction perpendicular to the length direction of the drum  201 . The length direction of the drum  201  is parallel to the axis  171  of the mounting shaft  17 . 
     In this example, the first support arm  2031  connects the first end of the drum  201  and the connecting portion  202 , and the second support arm  2032  connects the second end of the drum  201  and the connecting portion  202 . The supporting portion  203  further includes a third support arm  2033 , and the third support arm  2033  is fixedly connected to the first support arm  2031  and second support arms  2032  to increase the overall strength and rigidity of the supporting portion  203 . The third support arm  2033  extends in a direction parallel to the mounting shaft  17 , and the two ends of the third support arm  2033  are respectively connected to the first support arm  2031  and the second support arm  2032 . 
     The drum  201  has a mid-division plane  21 ′ perpendicular to the length direction, and the drum  201  is symmetrical about the mid-division plane  21 ′; the supporting portion  203  has a symmetry plane  22 ′. The supporting portion  203  is symmetrical about the symmetry plane  22 ′. The symmetry plane  22 ′ is parallel or coincides with the mid-division plane  21 ′. When the connecting portion  202  is mounted to the middle position of the mounting shaft  17 , the symmetry plane  22 ′ coincides with the mid-division plane  21 ′. In other examples, the connecting portion  202  may be installed at any position in the axial direction of the mounting shaft  17 . 
     As shown in  FIG.  30   , the drum  201  includes a central shaft  2011  and a cylindrical portion  2012 . The central shaft  2011  extends along the length direction of the drum  201 ; the cylindrical portion  2012  rotates around the central shaft  2011 , and the cylindrical portion  2012  is basically a hollow cylindrical shape; both the central shaft  2011  and the cylindrical portion  2012  are made of metal. The central shaft  2011  and the supporting portion  203  are connected together by screws, and the central shaft  2011  and the screw form a threaded connection, that is, the central shaft  2011  and the supporting portion  203  constitute a fixed connection, and the cylindrical portion  2012  can rotate relative to the central shaft  2011 . In an example, the screw can be replaced with a bolt fixedly connected to the supporting portion  203  so that the central shaft  2011  can rotate about the bolt; in other words, the screw and the central shaft  2011  constitute a rotational connection, and the central shaft  2011  can rotate relative to the screw. 
     In this example, the lawn mower  100  includes an adjustment assembly not shown for adjusting the height of the deck  12  from the ground, and the grass pressing assembly  20  is connected to a shaft body on the adjustment assembly. The adjustment assembly in this example is mainly composed of a linkage mechanism. When the user adjusts the height of the deck  12  from the ground, the height of the adjustment assembly from the ground also changes. That is to say, the height of the mounting shaft  17  from the ground is variable. In this example, the mounting shaft  17  is parallel to the ground. The distance d from the axis  171  of the mounting shaft  17  to the axis  2011   a  of the central shaft  2011  of the drum  201  is long enough so that regardless of the height of the mounting shaft  17  from the ground, the drum  201  still contacts the ground and is supported by the ground. That is, the distance d between the axis  2011   a  of the central shaft  2011  and the axis  171  of the mounting shaft  17  is greater than the maximum distance between the axis  171  of the mounting shaft  17  and the ground. 
       FIG.  31    is a schematic diagram of the grass pressing assembly  20 ′ provided by a tenth example of the present application. Compared with the ninth example, the difference only lies in the structure of the supporting portion  203 ′, so only the supporting portion  203 ′ will be described below. The supporting portion  203 ′ includes a first support arm  2031 ′, a second support arm  2032 ′, and a third support arm  2033 ′. The two ends of the third support arm  2033 ′ are respectively connected to the two ends of the drum  201 ′; the two ends of the first support arm  2031 ′ are respectively connected to the third support arm  2033 ′ and the connecting portion  202 ′, and the two ends of the second support arm  2032 ′ are respectively connected to the third support arm  2033 ′ and the connecting portion  202 ′. Among them, the connection of the first support arm  2031 ′ and the second support arm  2032 ′ are fixed connections, including welded connection or threaded connection. The two ends of the third support arm  2033 ′ extend approximately in a direction perpendicular to the mounting axis  17 ′, the middle part of the third support arm  2033 ′ extends approximately in a direction parallel to the mounting axis  17 ′, the first support arm  2031 ′ and the second support arm  2032 ′ extend in a direction perpendicular to the mounting axis  17 ′. 
       FIG.  32    is a schematic diagram of a lawn mower  50  provided in an eleventh example of the present application. Compared with the first example, the difference mainly lies in the structure and position arrangement of the lighting assembly. The following mainly introduces the lighting assembly  508 . As shown in  FIGS.  32 - 34   , the lawn mower  50  includes a main body  501  and an operating device  502 . The main body  501  includes a main body housing  5011 , a prime mover, and a working assembly  5013 , wherein the working assembly  5013  includes working elements that perform the tool functions of garden tools. For the lawn mower  50 , the working element is a cutting element arranged for mowing, further, is a blade assembly  5013   a . The main body housing  5011  is configured to install a prime mover and a working element that outputs power. For the lawn mower  50 , the main body housing  5011  may include a deck  60 . The prime mover is configured to output power to the working element to drive the movement of the working element. In this example, the prime mover is a motor  5012  capable of driving the blade assembly  5013   a  to rotate. The operating device  502  is configured for user operation to control the main body  501 , and the operating device  502  includes an operating element for user operation, the operating element being a trigger  5021 . As a hand-push power tool, the lawn mower  50  also includes a connecting rod assembly, which is connected to the main body  501  and the operating device  502 . The lawn mower  50  further includes a pair of walking wheels  5014 . The walking wheels  5014  drive the lawn mower  50  to walk on the ground. The two walking wheels  5014  are symmetrically disposed on both sides of the first plane  501 ′. 
     The connecting rod assembly includes a pair of connecting rods  5031 , and the connecting rod  5031  connects the main body  501  and the operating device  502 . The two connecting rods  5031  are arranged symmetrically on both sides of the first plane  501 ′. In the present example, the area at the end of the connecting rod assembly  503  where the operating device  502  is provided is defined as the operating area  505 , the area at the end of the connecting rod assembly  503  where the main body  501  is provided is defined as the work area  503 , the operating device  502  is located in the operating area  505 , the main body  501  is located in the work area  503 . The connecting rod assembly further includes an armrest  5032 ; the armrest  5032  is configured for a user standing in an operation position to hold and push the lawn mower  50 . The armrest  5032  connects the two connecting rods  5031  and is located at the end of the connecting rods  5031  away from the main body  501 . 
     As shown in  FIGS.  32 - 35   , a signal acquisition system  5023  is also provided in the operating area  505 . The signal acquisition system  5023  is connected to the operating device  502  to receive input information of the operating device  502 . A signal output system  5015  is also provided in the working area  503 , and the signal output system  5015  is configured to control the output of the working assembly  5013 . The operating device  502  further includes a console  5022 ; the console  5022  connects the two connecting rods  5031 ; the console  5022  is located between the armrest  5032  and the main body  501 . The trigger  5021  and the console  5022  constitute a rotational connection. The user can rotate the trigger  5021  so that the trigger  5021  fits to the armrest  5032 . The user&#39;s hand simultaneously holds the trigger  5021  and the armrest  5032 . The signal acquisition system  5023  is arranged in a space surrounded by the console  5022 . The signal output system  5015  is arranged in a space surrounded by the main body housing  5011 . 
     The lawn mower  50  further includes a signal line assembly  504 ; the signal line assembly  504  is connected to the signal output system  5015  and the signal acquisition system  5023  so that the signal output system  5015  and the signal acquisition system  5023  constitute a communication connection. In this way, after the signal acquisition system  5023  collects the signals output by the operating device  502 , the signal line assembly  504  transmits the information to the signal output system  5015 . The signal output system  5015  controls the working assembly  5013  to perform the corresponding function in a corresponding state. 
     The signal acquisition system  5023  includes a signal circuit board  5023   a , and the signal output system  5015  includes a first output circuit board  5015   a . The first output circuit board  5015   a  is connected to the motor  5012 . The signal circuit board  5023   a  is configured to install or connect a signal switch, which is controlled by the operating element. The first output circuit board  5015   a  sends signals to the working elements, electronic switches, circuit boards, etc. in the working area  503 . The signal line assembly  504  comprises a first signal line  5041 ; the first signal line  5041  is connected to the first output circuit board  5015   a  and the signal circuit board  5023   a  in order to achieve the communication between the first output circuit board  5015   a  and the signal circuit board  5023   a.    
     Garden tools in related technologies connect multiple electronic components through power lines and electronic switches. The power loss is large, the cost of cables is high, and the wiring is complicated, resulting in chaos in the internal structure of the machine. In this example, the first signal line  5041  is used to connect the signal circuit board  5023   a  and the first output circuit board  5015   a , and a bus signal line can realize the connection between multiple electronic components. Therefore, regarding the lawn mower  50  of this example, the power loss is low, the cost of the cable is low, and the wiring is simple, so that the internal structure of the machine is simple. Moreover, because there are few cables inside the lawn mower  50 , the cable arrangement is simple, the stability of the lawnmower  50  is good, it is not easy to be damaged, and maintenance is relatively convenient. 
     In this example, the signal acquisition system  5023  is only provided with one signal circuit board  5023   a . In other examples, the signal acquisition system  5023  also includes multiple signal circuit boards  5023   a , and the multiple signal circuit boards  5023   a  are communicatively connected through signal lines. 
     The lawn mower  50  further comprises a power supply; the power supply is a battery pack  5016 ; the battery pack  5016  is configured to power the motor  5012 ; the battery pack  5016  and the motor  5012  are both mounted on the main body  501 . The signal output system  5015  further includes a second output circuit board  5015   b , and the second output circuit board  5015   b  is disposed in the main body housing  5011 . The second output circuit board  5015   b  and the battery pack  5016  constitute a communication connection. The first signal line  5041  is also connected to a splitter  5042 , which is connected to two output terminals  5042   a , which are respectively connected to the first output circuit board  5015   a  and the second output circuit board  5015   b  referring to  FIG.  34    and  FIG.  35   . Thus, the first output circuit board  5015   a  is communicatively connected to the first signal circuit board  5023   a  through the first signal line  5041 , and the second output circuit board  5015   b  is communicatively connected to the first signal circuit board  5023   a  through the first signal line  5041 . 
     In this example, the working assembly  5013  further includes other functional elements that implement additional functions of the lawn mower  50 , and the functional elements may be, for example, a lighting element  5081  or a self-propelled motor. In this example, the lighting element  5081  is an example of the functional elements. The lawn mower  50  also includes a third output circuit board  5015   c  that controls the lighting element  5081 , and the third output circuit board  5015   c  is connected to the first output circuit board  5015   a.    
     The first output circuit board  5015   a  is also installed or connected with a first access terminal  5015   d , and the first access terminal  5015   d  is configured to receive a signal output by the first signal line  5041 . The second output circuit board  5015   b  is also installed or connected with a second access terminal  5015   e , which is configured to receive the signal output by the first signal line  5041 . The first access terminal  5015   d  is connected to one of the two output terminals  5042   a  connected to the splitter  5042 , and the second access terminal  5015   e  is connected to the other one of the two output terminals  5042   a  connected to the splitter  5042 . The two output terminals  5042   a  are provided with USB female sockets, and the first access terminal  5015   d  and the second access terminal  5015   e  are provided with USB male sockets. In one example, the USB female socket is a TYPE-C female socket, and the USB male socket is a TYPE-C male socket. In this way, the signal line assembly  504  has good versatility, is convenient for maintenance, and can improve the stability of the lawn mower  50 . In other examples, the output terminal  5042   a  may be provided with a USB male socket, and the first access terminal  5015   d  and the second access terminal  5015   e  may be provided with a USB female socket. 
       FIG.  36    is a schematic diagram of a lawn mower  50  provided in a twelfth example. The signal output system  5051  of the lawn mower  505  includes a first output circuit board  5052  and a second output circuit board  5053 . The motor  5054  and the battery pack  5055  are both connected to the first output circuit board  5052 , and the signal circuit board  5056  and the first output circuit board  5052  are connected by a signal line. The second output circuit board  5053  is connected to the functional element  5057  which is configured to realize other functions of the lawn mower  505 . 
     As shown in  FIG.  32    and  FIG.  37   , the lawn mower  50  further includes a lighting assembly  508  and a status display assembly  509 . Lighting assembly  508  includes a lighting switch  5082  and a lighting element  5081  as shown in  FIG.  32   . The lighting element  5081  is disposed in the working area  503  to illuminate the region on the front side of the lawn mower  50  so as to facilitate the user working in poor lighting conditions. The lighting element  5081  is provided on the main body  501 , further, the lighting element  5081  is provided on the main body housing  5011 . The lighting switch  5082  is provided for user operation to control whether the lighting element  5081  is turned on. The status display assembly  509  includes a status indicator light  5091 . The status indicator light  5091  can display the working status of the lawn mower  50 . The status indicator light  5091  can also display whether the lawn mower  50  is activated. Among them, the lighting switch  5082  and the status indicator light  5091  are both located in the operating area  505 . In this way, when the user stands on the rear side of the operating device  502 , the user can conveniently operate the lighting switch  5082  to light up the lighting element  5081 . Especially during the operation of the lawn mower  50 , the user does not need to release the trigger  5021  and come to the side or the front of the lawn mower  50  to activate the lighting element  5081 . Therefore, the user can conveniently operate the lighting switch  5082  at any time during the operation of the lawn mower  50 , which improves the operational convenience. Moreover, the user can easily observe the display state of the status display assembly  509 , without leaving the operating area. 
     The lighting switch  5082  and the status indicator light  5091  are both provided on the console  5022 ; also, the lighting switch  5082  and the status indicator light  5091  are located between the trigger  5021  and the main body  501 , thereby facilitating user operations. 
     As shown in  FIGS.  33 ,  36 , and  37   , a safety switch  5024  is also provided in the middle of the console  5022 . The safety switch  5024  and the trigger  5021  constitute a switch group for starting the motor  5054 . When one of the safety switch  5024  and the trigger  5021  is not activated, the lawn mower  50  is not started. After the safety switch  5024  is activated, the user activates the trigger  5021 . If the safety switch  5024  is not activated, the motor  5054  does not start when the user activates the trigger  5021 . Among them, the lighting switch  5082  and the status indicator light  5091  are respectively located on both sides of the safety switch  5024 , therefore, the structure layout on the console  5022  is more reasonable, and it is more convenient for the user to operate the lawn mower  50 . 
     In this example, the lighting switch  5082  and the status indicator light  5091  are also disposed on both sides of the first plane  501 ′, which facilitates the user to operate the lighting switch  5082  and to observe the display status of the status indicator light  5091 . In other examples, the lighting switch  5082  may also be provided on the armrest  5032  or near the armrest  5032 , so long as the user can operate the lighting switch  5082  when standing on the rear side of the lawn mower  50  without leaving the operating area  505 . 
     The armrest  5032  includes a cross bar  5032   a ; the cross bar  5032   a  is for the user to grip and the cross bar  5032   a  extends in a direction perpendicular to the connecting rod  5031 . The minimum distance between the lighting switch  5082  and the cross bar  5032   a  is greater than or equal to 0 cm and less than or equal to 30 cm. In this way, the user can extend the arm to operate the light switch  5082  when holding the cross bar  5032   a.    
     In one example, the lighting switch  5082  is a membrane switch, which takes up little space and has a low manufacturing cost. The lighting switch  5082  is also provided with an LED lamp for the user to easily observe whether the lighting switch  5082  is triggered in a relatively bright environment. 
     In this example, the number of status indicator lights  5091  is five, and the five status indicator lights  5091  are respectively: working status indicator light, working shape indicator light, temperature status indicator light, load status indicator light and power status indicator light. The working status indicator light indicates whether the lawn mower  50  is started, so whether the lawn mower  50  has been damaged is determined by the display status of the working status display light. The working shape indicator light shows the folding state of the lawn mower  50  or the telescopic state of the connecting rod assembly  503  of the lawn mower  50 . The temperature status display light indicates whether the temperature of the battery pack  5055  or the motor  5054  exceeds a predetermined threshold. The load status indicator light indicates whether the lawn mower  50  is in an overload state. The power status indicator light displays the remaining power of the battery pack  5055 , or whether the remaining power of the battery pack  5055  is lower than a predetermined threshold. 
     As shown in  FIGS.  32 ,  33 , and  38   , the deck  60  is formed with an accommodation space  60   a  covering the blade assembly  5013   a . In the accommodation space  60   a , the blade assembly  5013   a  rotates about the rotation axis  504 ′ to perform the cutting function. 
     As shown in  FIG.  38    and  FIG.  41   , the lawn mower  50  has a discharge mode and a mulch mode. When the lawn mower  50  is in the discharge mode, the grass clippings can be discharged out of the deck  60 . When the lawn mower is in the mulch mode, the grass clippings will fall under the deck  60 . 
     As shown in  FIGS.  38 - 40   , the deck  60  includes a vortex portion  601  and a discharge portion  602 . The vortex portion  601  extends around the circumferential direction of the rotation axis  504 ′ to form a vortex in the accommodation space  60   a . The vortex portion  601  forms a vortex channel  6011 , and the vortex flows along a flow path  60   b  in the vortex channel  6011 . The flow path  60   b  also basically extends in the circumferential direction around the rotation axis  504 ′. The discharge portion  602  is provided on the flow path  60   b  of the vortex. The discharge portion  602  extends from the vortex portion  601  in the tangential direction of the vortex, and the discharge portion  602  guides the vortex flow out in the tangential direction of the flow path  60   b . Therefore, when the lawn mower  50  is in the discharge mode, the discharge portion  602  can guide the grass clippings to move along the flow path  60   b  of the vortex channel  6011  first, and then when the grass clippings move to the discharge portion  602 , the discharge portion  602  will guide a portion of grass clippings away from the deck  60  along the tangential direction of the flow path  60   b  to discharge this portion of grass clippings to the outside of the lawn mower  50 , or collect this portion of grass clippings into a grass basket. 
     As shown in  FIG.  41   , the lawn mower  50  further includes a plug  6017 . When the plug  6017  is installed in the discharge portion  602 , the discharge portion  602  is sealed, so that the lawn mower  50  is in the mulch mode. When the plug  6017  is not attached to the discharge portion  602 , the discharge portion  602  is opened, and the airflow can flow out from the discharge portion  602 , therefore the lawn mower  50  is in the discharge mode. 
     In the present example, as shown in  FIG.  38    and  FIG.  40   , the deck  60  further comprises a stop portion  603 ; the stop portion  603  is configured to prevent the vortex from keeping circulating in the vortex portion  601  while flowing through the discharge portion  602 , thereby increasing the flow rate of the vortex from the discharge portion  602 . At least a portion of the discharge portion  602  and at least a portion of the stop portion  603  is on the same side of the first plane  501 ′, and the first plane  501 ′ passes through the rotation axis  504 ′. The stop of the vortex by the stop portion  603  can increase the flow rate of the vortex from the discharge portion  602  when the lawn mower  500  is in the discharge mode, thereby improving the grass collection efficiency of the grass clippings, and on the other hand, when the lawn mower  500  is in the mulch mode, the grass clippings can be stopped so that some of the grass clippings fall into the cutting area of the blade assembly  5013   a  again to be cut by the blade assembly  5013   a  again, thereby improving the grass chopping ability. 
     In one example, the deck  60  further includes a mounting portion  604 ; the mounting portion  604  is configured to mount the motor  5054 . The mounting portion  604  is formed with a hole  6041  around the rotation axis  504 ′ that allows the motor shaft to pass. 
     As shown in  FIG.  39   , the vortex portion  601  includes an inner ring  6012 , an outer ring  6013 , and a bottom surface  6014 . The inner ring  6012  is formed around the rotation axis  504 ′, and the inner ring  6012  is connected to the mounting portion  604 . The outer ring  6013  is disposed around the inner ring  6012 . The bottom surface  6014  connects the inner ring  6012  and the outer ring  6013 . The vortex channel  6011  of the vortex portion  601  is formed between the inner ring  6012  and the outer ring  6013 . 
     The discharge portion  602  includes a first discharge surface  6021 , a second discharge surface  6022 , and a discharge bottom surface  6023 . The first discharge surface  6021  is connected to the inner ring  6012 , and the second discharge surface  6022  is connected to the outer ring  6013 . The first discharge surface  6021  extends from the inner ring  6012  substantially along a tangential direction of the inner ring  6012 , and the second discharge surface  6022  extends from the outer ring  6013  substantially along a tangential direction of the outer ring  6013 . The discharge bottom surface  6023  connects the first discharge surface  6021  and the second discharge surface  6022 . The discharge bottom surface  6023  is also connected to the bottom surface  6014  of the vortex section  601 . 
     The stop portion  603  includes a stop surface  6031  and a connecting surface  6032 . The stop surface  6031  is configured to stop the airflow flowing in the vortex portion  601  so that the airflow flows out of the discharge portion  602 . The discharge portion  602  is substantially located on the first side of the first plane  501 ′. In this example, if more than 90% of the discharge portion  602  is located on the first side of the first plane  501 ′, it is considered that the discharge part  602  is substantially located on the first side of the first plane  501 ′. The stop surface  6031  is also located on the first side of the first plane  501 ′, that is, the stop surface  6031  and the discharge portion  602  are located on the same side of the first plane  501 ′. Or, in other examples, the stop surface  6031  and a portion of the discharge portion  602  are located on the same side of the first plane  501 ′. Alternatively, in other examples, at least a portion of the stop surface  6031  and at least a portion of the discharge portion  602  are located on the same side of the first plane  501 ′. 
     The stop portion  603  is provided at the edge of the discharge portion  602 . In an example, the stop surface  6031  is disposed at the first discharge surface  6021 , and the stop surface  6031  extends from the inner ring  6012  to the outer ring  6013 . The stop surface  6031  also extends from the bottom surface  6014  to the direction away from the bottom surface  6014 , that is, one side of the stop surface  6031  is connected to the junction of the bottom surface  6014  and the first discharge surface  6021 . The connecting surface  6032  extends from a side of the stop surface  6031  away from the bottom surface  6014  along a plane obliquely intersecting the stop surface  6031 , and the connecting surface  6032  connects the stop surface  6031  and the bottom surface  6014 . 
     In this example, the stop portion  603  is integrally formed with the vortex portion  601 , and the recess of the vortex portion  601  towards the ground forms the stop portion  603 . The stop portion  603  is located inside the vortex portion  601 , the stop portion  603  is also located in the vortex channel  6011  formed by the vortex portion  601 , and the stop portion  603  is also located on the flow path  60   b  of the vortex. 
     The stop portion  603  and the discharge portion  602  are also disposed on the same side of a second plane  502 ′ that passes through the rotation axis  504 ′ and is perpendicular to the first plane  501 ′. That is to say, the stop portion  603  and the discharge portion  602  are provided at the rear of the deck  60 . 
     In a direction perpendicular to the first plane  501 ′, at least a portion of the stop portion  603  is also located between the discharge portion  602  and the hole  6041 . 
     The ratio of the length L 1  of the stop portion  603  in the direction of the rotation axis  504 ′ to the depth L 2  of the vortex portion  601  in the direction of the rotation axis  504 ′ is greater than or equal to 0.1 and less than or equal to 0.5. Therefore, on the one hand, the size of the stop portion  603  is not too large, which hinders effective vortex to be generated in the vortex portion  601 ; on the other hand, the size of the stop portion  603  is not too small, which affects the discharge efficiency of the discharge portion  602  and the grass chopping ability of the lawn mower  50 . 
       FIG.  42    is a lawn mower  10  provided in a thirteenth example of the present application. Compared with the first example, the structure of the blade assembly  101  is the main difference. As shown in  FIGS.  42 - 46   , the lawn mower  10  includes a blade assembly  101  for cutting vegetation and a deck  102  that houses the blade assembly  101 , and the blade assembly  101  is located inside the deck  102 . The lawn mower  10  further includes a motor  103  that drives the blade assembly  101  to rotate. The motor  103  is located above the deck  102 . The motor  103  and the blade assembly  101  form a coaxial rotation about the rotation axis  10 ′. The motor  103  includes a motor shaft, and the blade assembly  101  includes a drive shaft  1011  referring to  FIG.  44    that drives the blade assembly  101  to rotate. The drive shaft  1011  may be a motor shaft. In an example, a transmission mechanism for transmission may also be provided between the motor  103  and the blade assembly  101 , so that the shaft of the motor  103  and the drive shaft  1011  form a non-coaxial rotation. 
     As shown in  FIGS.  44 - 46   , the blade assembly  101  includes a first blade  1012  and a second blade  1013 . The first blade  1012  is located above the second blade  1013  relative to the ground, and the first blade  1012  and the second blade  1013  both rotate about a rotation axis  10 ′. The first blade  1012  and the second blade  1013  constitute a synchronous rotation. As shown in the direction of the arrow in  FIG.  44   , the first blade  1012  and the second blade  1013  rotate synchronously in the rotation direction  10   a ′ about the drive shaft  1011 . The blade assembly  101  further includes a connecting assembly  1014 . The first blade  1012  and the second blade  1013  form a fixed connection through the connecting assembly  1014 . In this example, the first blade  1012  and the second blade  1013  form a detachable connection through the connecting assembly  1014 . It is convenient to repair or replace the blade assembly  101  later. The connecting assembly  1014  includes a connecting piece, a nut, and the like. The connecting assembly  1014  may also connect the first blade  1012  and the second blade  1013  with other connection structures. The specific connection form between the first blade  1012  and the second blade  1013  is not limited herein. The blade assembly  101  may also include other accessories such as bearings and bearing covers. 
     Along the rotation direction  10   a ′, the first blade  1012  is located in front of the second blade  1013 , that is to say, although the first blade  1012  and the second blade  1013  rotate synchronously when the motor  103  is started, the first blade  1012  cuts the vegetation earlier than the second blade  1013 . In this example, the rotation direction  10   a ′ is a clockwise direction with the drive shaft  1011  as the axis. The first blade  1012  includes a first mounting portion  1012   a  and a first cutting portion  1012   b . The first mounting portion  1012   a  is located in the middle of the first blade  1012 . The first mounting portion  1012   a  is configured to connect the first blade  1012  and the second blade  1013  and the drive shaft  1011 . The first cutting portion  1012   b  is symmetrically disposed at both ends of the first blade  1012  about the drive shaft  1011 , and the first cutting portion  1012   b  is configured to cut vegetation. Similarly, the second blade  1013  includes a second mounting portion  1013   a  located in the middle and second cutting portions  1013   b  symmetrically disposed at both ends. The difference is that the middle part and the two ends of the first blade  1012  are substantially on the same plane, that is to say, the first mounting part  1012   a  and the first cutting portion  1012   b  are on the same plane, and the entire first blade  1012  substantially expands along a plane surface; whereas the middle part and the two ends of the second blade  1013  are located on different planes. The two ends of the second blade  1013  are located below the middle part of the second blade  1013  with respect to the ground, that is, the second cutting portion  1013   b  is located below the second mounting portion  1013   a  with respect to the ground, and the entire second blade  1013  expands along a curved surface. In this example, the first mounting portion  1012   a  and the second mounting portion  1013   a  vertically overlap and intersect obliquely, the first mounting portion  1012   a  and the second mounting portion  1013   a  constitute a fixed connection referring to  FIGS.  45  and  46    through the connecting member  1014   a . The connecting member  1014   a  is provided with pins of different shapes, and the first mounting portion  1012   a  and the second mounting portion  1013   a  are respectively provided with holes for engaging with the pins, so as to form fixed connections with the connecting member  1014   a . In this example, the first mounting portion  1012   a  and the second mounting portion  1013   a  are provided with round holes and irregular-shaped limit holes. 
     The first cutting portion  1012   b  of the first blade  1012  is provided with a first cutting edge  1012   c  for cutting vegetation. The first cutting edge  1012   c  is disposed at the leading edge of the first cutting portion  1012   b . The leading edge refers to the edge of the first cutting portion  1012   b  that cut vegetation earliest when the first blade  1012  rotates along the rotation direction  10   a ′. The leading edges of the first cutting portions  1012   b  at both ends of the first blade  1012  are symmetrically provided with the first cutting edge  1012   c  about the drive shaft  1011 . Similarly, the leading edges of the second cutting portions  1013   b  at both ends of the second blade  1013  are also symmetrically provided with a second cutting edge  1013   c.    
     The first cutting edge  1012   c  and the second cutting edge  1013   c  respectively include a hardened portion for cutting vegetation. The hardened portion has a higher hardness than other parts due to a hardening process. In an example, the entire first cutting edge  1012   c  and second cutting edge  1013   c  are hardened, and the hardness is higher than other parts of the first blade  1012  and the second blade  1013 . 
     The first blade  1012  further includes a weight reduction portion  1012   d ; the weight reduction portion  1012   d  is disposed at the end of the first blade  1012 , and behind the first cutting edge  1012   c  and in front of the second cutting edge  1013   c  in the rotation direction  10   a ′, that is, the weight reduction portion  1012   d  is the portion of the end of the first blade  1012  opposite the first cutting edge  1012   c . The weight reduction portion  1012   d  is disposed symmetrically on both ends of the first blade  1012 , and the weight reduction portion  1012   d  has a recess relative to the first blade  1012 . The weight reduction portion  1012   d  reduces the weight of the first blade  1012  and expands the space between the first blade  1012  and the second cutting edge  1013   c  to facilitate secondary cutting of the vegetation cut by the first cutting edge  1012   c . The first blade  1012  further includes a shrinking edge  1012   e  inclined or curved with respect to the trailing edge of the first blade  1012 , and the shrinking edge  1012   e  is disposed at the trailing edge of the end of the first blade  102 . In this example, the shrinking edge  1012   e  is part of the edge of the weight reduction portion  1012   d , and the shrinking edge  1012   e  is inclined towards the inside of the first blade  1012  with respect to the trailing edge of the first blade  1012 . Along the rotation direction  10   a ′, the shrinking edge  1012   e  is located in front of the second cutting edge  1013   c ; the projection of the shrinking edge  1012   e  on the ground and the projection of the second cutting edge  1013   c  on the ground do not intersect. That is to say, since the shrinking edge  1012   e  is inclined or curved forward with respect to the trailing edge of the first blade  1012 , the projection of the shrinking edge  1012   e  and the second cutting edge  1013   c  has no overlapping portion in a plane parallel to the ground. 
     As shown in  FIG.  46   , the shrinking edge  1012   e  and the trailing edge of the first blade  1012  form a continuous curve with at least one bending point B. The projection of the bending point B on the ground is located in front of the projection of the second cutting edge  1013   c  on the ground in the rotation direction  10   a ′. That is to say, the bending point B formed by the shrinking edge  1012   e  and the trailing edge of the first blade  1012  is located outside the second cutting edge  1013   c  in a plane parallel to the second blade  1013 , while the lateral distance of the projection of the bending point B in the plane of the second blade  1013  to the second cutting edge  1013   c  is greater than 0. In an example, the shrinking edge  1012   e  and the trailing edge of the first blade  1012  may form multiple bending points. In this case, the multiple bending points should also meet the above conditions, that is, the projection of the bending point on the ground is located in front of the projection of the second cutting edge  1013   c  on the ground along the rotation direction  10   a ′, and the lateral distance from the bending point to the second cutting edge  1013   c  is greater than 0. 
     On the other hand, the length L 3  of the shrinking edge  1012   e  is greater than or equal to 40 mm and less than or equal to 150 mm. In one example, the length L 3  of the shrinking edge  1012   e  is greater than or equal to 70 mm and less than or equal to 100 mm. In this example, the length L 3  of the shrinking edge  1012   e  is about 95 mm. 
     The projection of the shrinking edge  1012   e  on the ground and the projection of the second cutting edge  1013   c  on the ground do not intersect, which makes full use of the length of the second cutting edge  1013   c  for secondary cutting, while enlarging the space formed by the shrinking edge  1012   e  and the second cutting edge  1013   c . Therefore, the vegetation cut by the first cutting edge  1012   c  rebounds and falls into the space to be cut by the second cutting edge  1013   c , thereby improving the cutting efficiency of the lawn mower  10 . 
     As the first blade  1012  and the second blade  1013  are arranged to overlap each other, the extension line of the shrinking edge  1012   e  and the extension line of the second cutting edge  1013   c  form an angle within a predetermined angle range. In an example, the angle between the extension line of the shrinking edge  1012   e  and the extension line of the second cutting edge  1013   c  is greater than or equal to 15 degrees and less than or equal to 45 degrees. In one example, the angle between the extension line of the shrinking edge  1012   e  and the extension line of the second cutting edge  1013   c  is greater than or equal to 25 degrees and less than or equal to 35 degrees. In this example, the angle is approximately 30 degrees. 
     The second blade  1013  further includes a tilted portion  1013   d  provided at both ends of the second blade  1013 , and the tilted portion  1013   d  lifts upward and distributes symmetrically on both ends of the second blade  1013  with respect to the drive shaft  1011 . After the air flow generated during the rotation of the second blade  1013  is lifted by the tilted portion  1013   d , the grass clippings cut by the second blade  1013  can be brought up and thrown up, therefore, the second blade  1013  has good performance in throwing the grass clippings. 
     A noise reduction portion capable of reducing noise is also provided near the tilted portion  1013   d , and the noise reduction portion is a noise reduction groove recessed inward. 
       FIG.  47    and  FIG.  48    are schematic diagrams of the lawn mower  30  provided in a fourteenth example of the present application. In this example, the lawn mower  30  may be a hand-push lawn mower or a riding lawn mower. The lawn mower  30  includes a blade assembly  301 , a transmission mechanism, a motor, a housing  302 , a handle  303 , and wheels  304 . 
     The motor drives the blade assembly  301  to rotate about the rotation axis  301 ′ in the cutting direction  30   a ′, wherein the cutting direction  30   a ′ is the clockwise or counter clockwise direction around the rotation axis  301 ′. The transmission mechanism connects the blade assembly  301  and the motor, and transmits the power of the motor to the blade assembly  301 . The housing  302  immobilizes or accommodates the motor. As the main frame structure of the lawn mower, the housing  302  assembles multiple parts into a whole. The lawn mower  30  also includes a battery pack that supplies power to the motor. The housing  302  includes a motor housing and a main body housing. The motor housing is configured to immobilize or accommodate the motor. The motor housing is connected to the main body housing. A circuit board to control the motor is provided in the housing  302 . 
     The handle  303  is formed with a grip portion for the user to grip. The handle  303  may be formed by the housing  302  or may be attached to the housing  302  as a separate part. The lawn mower  30  further includes a connecting rod connecting the handle  303  and the housing  302 , and the connecting rod is telescopic and rotatable relative to the housing  302 . The lawn mower  30  further includes a self-propelled motor that drives the wheels  304  to rotate. The self-propelled motor and the wheels  304  transfer motion with a transmission structure. In an example, the self-propelled motor and the wheels  304  transfer motion with a transmission gear. 
     As shown in  FIGS.  48 - 50   , the blade assembly  301  includes a blade  3011  and a rotating shaft  3012 . The rotating shaft  3012  has a rotation axis  301 ′ as a central axis, and the blade  3011  is symmetrical about the rotation axis  301 ′; the blade  3011  extends substantially along a straight line perpendicular to the rotation axis  301 ′; the blade  3011  extends substantially along a plane perpendicular to the rotation axis  301 ′. The blade  3011  includes a bottom surface  3011   a  and a top surface  3011   b . The top surface  3011   b  is further away from the ground relative to the bottom surface  3011   a . In this example, the bottom surface  3011   a  and the top surface  3011   b  are parallel to each other and are both perpendicular to the rotation axis  301 ′. In one example, the bottom surface  3011   a  is a curved surface, and at least a portion of the bottom surface  3011   a  is inclined with respect to the top surface  3011   b ; in one example, the top surface  3011   b  is a curved surface, and at least a portion of the top surface  3011   b  is inclined with respect to the bottom surface  3011   a.    
     The blade  3011  further includes a cutting surface  3011   c . The cutting surface  3011   c  is a plane between the bottom surface  3011   a  and the top surface  3011   b . The plane on which the cutting surface  3011   c  is located intersects the plane on which the bottom surface  3011   a  is located and the plane on which the top surface  3011   b  is located obliquely. That is to say, the cutting surface  3011   c  connects the bottom surface  3011   a  and the top surface  3011   b  and forms a continuous curved surface. The inclination angle between the cutting surface  3011   c  and the bottom surface  3011   a  is greater than or equal to 20 degrees and less than or equal to 35 degrees. In this example, the inclination angle between the cutting surface  3011   c  and the bottom surface  3011   a  is about 28 degrees, and the inclination angle between the cutting surface  3011   c  and the top surface  3011   b  is about between 30 degrees to 52 degrees. The blade  3011  also includes a cutting portion  3011   d ; the cutting portion  3011   d  is located at one end of the blade  3011  and at the leading edge of the blade  3011  along the cutting direction  30   a ′. The leading edge refers to the edge that contacts the vegetation first when the blade  3011  rotates along the cutting direction  30   a ′, and the edge that contacts the vegetation after the leading edge is the trailing edge, as shown in  FIG.  49   . In one example, the blade  3011  includes two cutting portions  3011   d , and the two cutting portions  3011   d  are respectively located at both ends of the blade  3011  and at the leading edge of the blade  3011  along the cutting direction  30   a′.    
     The cutting portion  3011   d  is defined by the bottom surface  3011   a  and the cutting surface  3011   c ; in this example, since the bottom surface  3011   a  and the cutting surface  3011   c  intersect obliquely, the cutting portion  3011   d  is formed by the bottom surface  3011   a  and the cutting surface  3011   c , and the bottom surface  3011   a  and the cutting surface  3011   c  intersect to form the cutting edge; in one example, the plane where the cutting surface  3011   c  is located obliquely intersects with the bottom surface  3011   a , but the cutting surface  3011   c  does not directly intersect with the bottom surface  3011   a ; in comparison, the cutting portion  3011   d  with the cutting edge is sharper and the cutting efficiency is also higher. 
     The cutting portion  3011   d  is composed of a body portion  3011   e  and a hardened portion  3011   f , wherein the hardened portion  3011   f  extends inward along the end of the blade  3011  and extends from the bottom surface  3011   a  to the top surface  3011   b  of the blade  3011 . The hardened portion  3011   f  is a hardened layer from laser quenching a part of the cutting portion  3011   d , whereas the body portion  3011   e  is not laser quenched, therefore, the surface hardness of the hardened portion  3011   f  is greater than the surface hardness of the body portion  3011   e . In one example, the ratio of the surface hardness of the hardened portion  3011   f  of the blade  3011  to the surface hardness of the body portion  3011   e  is greater than 1.1 and less than or equal to 2.4. In one example, the ratio of the surface hardness of the hardened portion  3011   f  to the surface hardness of the body portion  3011   e  is greater than 1.2 and less than or equal to 2. The surface hardness distribution of the hardened portion  3011   f  and the body portion  3011   e  makes the structure of the blade  3011  more reasonable. The hardened portion  3011   f  is a cutting portion  3011   d  near the bottom and end of the blade  3011 , which is a high-frequency region for cutting vegetation. Accordingly, the hardened portion  3011   f  with a higher surface hardness can improve the wear resistance and cutting efficiency of the blade  3011 , and also improve the reliability and service life of the blade  3011  of the lawn mower  30 . 
     The method of manufacturing the blade  3011  includes: laser cutting and forming, laser cutting the metal sheet to obtain the blade  3011  in an unsharpened state; laser quenching, laser hardening the area where the hardened portion  3011   f  is located to improve the surface hardness of the area; processing the cutting portion  3011   d , processing the blade  3011  in the unsharpened state to create the cutting portion  3011   d ; and polishing the blade  3011 , polishing the blade  3011  to remove burrs generated during the processing of the blade  3011 . 
     The area where the hardened portion  3011   f  is located is shown in  FIGS.  49  and  50   . In an example, the hardened portion  3011   f  has a trapezoidal cross section and a rectangular vertical section. The length L of the hardened portion  3011   f  is greater than or equal to 50 mm and less than or equal to 120 mm; the lateral width W of the hardened portion  3011   f  is greater than or equal to 2 mm and less than or equal to 8 mm; the depth H of the hardened portion  3011   f  is greater than 0.2 mm and less than or equal to 1 mm. In an example, the depth H of the hardened portion  3011   f  is greater than 0.3 mm and less than or equal to 0.6 mm. In this example, the length L of the hardened portion  3011   f  is approximately 100 mm; the lateral width W of the hardened portion  3011   f  is approximately 5 mm, which is approximately equal to the lateral width of the cutting portion  3011   d ; the depth H of the hardened portion  3011   f  is approximately 0.5 mm. The depth H of the hardened portion  3011   f  refers to the depth of the hardened layer obtained by laser quenching the blade  3011 . The above-mentioned size setting of the hardened portion  3011   f  of the blade  3011  can save the manufacturing cost while ensuring the cutting strength. In addition, considering the different degrees of wear of the hardened portion  3011   f  and the body portion  3011   e , the above size design makes the cutting portion  3011   d  maintain a sharp state for a long time after wear. 
     Further, the ratio of the surface hardness of the hardened portion  3011   f  to the depth of the hardened portion  3011   f  is greater than or equal to 1000 HV1/mm and less than or equal to 2000 HV1/mm. In one example, the ratio of the surface hardness of the hardened portion  3011   f  to the depth of the hardened portion  3011   f  is greater than or equal to 1100 HV1/mm and less than or equal to 1500 HV1/mm. In an example, the surface hardness of the body portion  3011   e  is greater than or equal to 350 HV1 and less than or equal to 500 HV1, and the surface hardness of the hardened portion  3011   f  is greater than or equal to 550 HV1 and less than or equal to 750 HV1; in one example, the surface hardness of the body portion  3011   e  is greater than or equal to 380 HV1 and less than or equal to 440 HV1, and the surface hardness of the hardened portion  3011   f  is greater than or equal to 600 HV1 and less than or equal to 700 HV. 
     The blade assembly  301  further includes a bearing, and a connector or a fastener, etc. configured to fix and connect the blade  3011 . 
       FIG.  51    and  FIG.  52    respectively show a schematic diagram of a blade assembly  401  and a blade of a lawn mower provided in a fifteenth example of the present application. The present example differs from the fourteenth example in that: the blade assembly  401  comprises a shaft  4011 , a first blade  4012  and a second blade  4013 ; the first blade  4012  and the second blade  4013  are stacked up and down together to synchronously rotate about the rotation axis  401 ′; in an example, the first blade  4012  and the second blade  4013  are stacked up and down together to asynchronously rotate about the rotation axis  401 ′; in one example, the first blade  4012  and the second blade  4013  rotate about the first axis and the second axis respectively, and the first axis and the second axis are in parallel but do not coincide. 
     The first blade  4012  includes a first cutting portion  4012   d , and the second blade  4013  includes a second cutting portion  4013   d . Structural features such as the hardened portion and the body portion in the fourteenth example are applicable to the first blade  4012  and the second blade  4013  in this example.