Patent Publication Number: US-2023144059-A1

Title: Work machine

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims priority to and the benefit of Japanese Patent Application No. 2021-181407 filed on Nov. 5, 2021, the entire disclosure of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a work machine. 
     Description of the Related Art 
     Japanese Patent Laid-Open No. 2016-208950 discloses a guard mechanism  20  that protects a rotary blade  30  from foreign matter such as pebbles and protects an operator and nearby people from the rotating rotary blade  30 . The guard mechanism  20  includes one or a plurality of guard portions  21  that cover the rotary blades  30 , and the guard portions  21  are arranged in a direction parallel to the machine body longitudinal direction. 
     However, in the technology described in Japanese Patent Laid-Open No. 2016-208950, since the guard portion is the same in the machine body longitudinal direction, plants on the extension line of the guard portion are stepped on by the guard portion, and there is a problem that uncut parts are likely to occur. 
     The present invention has been made in response to the recognition of the above problems, and provides a technology for efficiently cutting plants while maintaining work safety. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the invention, there is provided a work machine comprising: a blade; a blade housing; and a guard pole portion provided below the blade, wherein the guard pole portion is supported by the blade housing, and the guard pole portion includes an inclined portion extending in an oblique direction with respect to a machine body longitudinal direction of the work machine. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings illustrating embodiments in the present invention constitute a part of the specification, and are used together with the description to describe the present invention. 
         FIG.  1    is a diagram illustrating an example of a structure of a lawn mower according to an embodiment; 
         FIG.  2    is a diagram illustrating an example of a guard pole according to the embodiment; 
         FIG.  3    is an explanatory view of a blade, a shearable region, and a blade housing according to the embodiment; 
         FIG.  4    is a diagram illustrating a structure of a lawn mower according to a modification example; 
         FIG.  5    is a diagram illustrating a structure of a lawn mower according to the modification example; and 
         FIG.  6    is a diagram illustrating an example of the structure of the lawn mower according to the embodiment. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments are not intended to limit the scope of the claimed invention, and limitation is not made an invention that requires all combinations of features described in the embodiments. Two or more of the multiple features described in the embodiments may be combined as appropriate. Furthermore, the same reference numerals are given to the same or similar configurations, and redundant description thereof is omitted. 
     In the following description, expressions such as front/rear, up/down, and lateral sides (left/right) will be used, in some cases, as expressions indicating relative directions indicated with respect to a vehicle body of a lawn mower as a reference. For example, the term “front” indicates the front side of the vehicle body in the front-and-rear direction, and the term “upper” indicates a height direction of the vehicle body. 
       FIG.  1    is a diagram illustrating an example of a structure of a lawn mower according to the present embodiment. The lawn mower according to the present embodiment is, for example, a self-propelled lawn mower that performs lawn mowing work while traveling independently.  FIG.  1    is a view of a lawn mower  10  observed from below. An upper side of the drawing is an advancing direction of the lawn mower  10 , that is, a front side of the lawn mower  10 , and a lower side of the drawing is a rear side of the lawn mower  10 . In addition, the right side of the drawing is the left side of the lawn mower  10 , and the left side of the drawing is the right side of the lawn mower  10 . The lawn mower  10  illustrated in  FIG.  1    includes a base portion  100 , wheels  110  to  140 , a guard pole portion  200 , a blade  300 , and a blade housing  400 .  FIG.  6    is a schematic diagram of an internal configuration of the lawn mower according to the present embodiment, which is observed from a horizontal direction. A driving source  600  including a battery and a motor, and an electronic control unit (ECU)  601  that controls the driving source  600  are arranged inside the lawn mower  10 . Under the control of the ECU  601 , the blade  300  rotates about a rotary shaft  310  by the drive of the driving source  600 , whereby plants can be cut. The lawn mower  10  also includes a driving source for traveling for driving wheels (for example, rear wheels), a camera for capturing images of an external environment, and the like, but these are not illustrated. The lawn mower  10  can cut plants while autonomously traveling by the ECU  601  analyzing a video of a camera (not illustrated) and controlling the driving source  600  and the driving source for traveling based on the analysis result. 
     The wheel  110  is a left front wheel, the wheel  120  is a left rear wheel, the wheel  130  is a right front wheel, and the wheel  140  is a right rear wheel. In the illustrated example, the vehicle travels on wheels, but other configurations such as a caterpillar may be used. 
     The guard pole portion  200  is a structure for protecting the blade  300  from foreign matters such as stones and protecting an operator and nearby people from the rotating blade. The guard pole portion  200  may be arranged on a plane parallel to the ground. The guard pole portion  200  includes a plurality of guard poles  210  and a support pole portion  220 . The plurality of guard poles  210  include guard poles  211  to  214 . The support pole portion  220  includes support poles  221  to  224 . In the illustrated example, four guard poles and four support poles are included, but the numbers are not limited. Each of the guard poles and support poles is, for example, a columnar pole made of a metal. Each of the guard poles and support poles can be, for example, a columnar pole having a diameter of approximately 8 mm, but the diameter can be any value depending on the size of the lawn mower  10 . The interval between the guard poles may be approximately 5 cm. An interval (for example, the interval is approximately the same as the interval between the guard poles, which is, for example, 5 cm) indicated by an arrow  150  is secured between the foremost guard pole  211  and the blade housing  400 . As a result, sufficient space is secured for plants that fall from the blade housing  400  to rise, and the cutting efficiency can be improved. 
     Both end portions of each of the plurality of guard poles  210  are connected to the blade housing  400 . The shape of a guard pole  211  included in the plurality of guard poles  210  will be described with reference to  FIG.  2   . The other guard poles have the same shape. The guard pole  211  includes an inclined portion extending in an oblique direction with respect to the machine body longitudinal direction of the lawn mower  10 . The oblique direction is a direction of approximately 45 degrees in the illustrated example, but may be, for example, any direction in a range of 15 degrees to 75 degrees with respect to the machine body longitudinal direction. The inclined portions of each guard pole may be parallel to each other. The inclined portions include a left inclined portion  211   c  and a right inclined portion  211   a  extending in the oblique direction respectively to the left and right with respect to the machine body longitudinal direction of the lawn mower  10 . The left inclined portion  211   c  and the right inclined portion  211   a  are continuous in an arc shape at the center of the lawn mower  10 . That is, the guard pole  211  includes the right inclined portion  211   a , an arc portion  211   b , and the left inclined portion  211   c . The arc-shaped parts of each of the guard poles  211  to  214  are concentrically arranged. 
     In a case where a plurality of guard poles are arranged in parallel in the advancing direction, the plants are always pushed down by the guard poles, and thus it is difficult to cut the plants with the blade  300  on the extension line of the guard poles, and uncut parts are likely to occur. On the other hand, in a case where a plurality of guard poles are arranged perpendicular to the advancing direction, after the plants are pushed down by the guard poles, the plants rise when the guard poles pass. However, the plants are pushed down again by the next guard pole before rising, and thus uncut parts are likely to occur similarly. 
     Here, since the guard pole  211  includes the inclined portion, it is possible to avoid a state where the plants are always pushed down as in a case where a plurality of guard poles are arranged in parallel with the advancing direction. In addition, since an interval A wider than an interval B between the guard poles in  FIG.  2    can be secured, it is easy to secure a distance for the plants to rise after the guard pole  211  passes, and it is possible to reduce uncut parts. In this manner, by providing the inclined portion on the guard pole, it is possible to improve the cutting efficiency while maintaining the safety of the operator and nearby people. 
     Both end portions of each of the support poles  221  to  224  of the support pole portion  220  are connected to the guard pole  214  in the example of  FIG.  1   . Each of the support poles  221  to  224  of the support pole portion  220  has an arc shape. The support poles  221  to  224  are arranged at equal intervals. 
     The blade  300  is an edge for cutting plants (for example, weeds, grass, and the like), and can cut the plants by rotating about the rotary shaft  310 . The blade and the shearable region will now be described with reference to  FIG.  3   . The blade  300  has shearing portions near both end portions, and rotation of the shearing portions enables cutting of plants at the position of the shearable region  350 . In other words, the shearable region  350  is an annular region having a predetermined width and formed by rotation of the shearing portion of the blade  300  about the rotary shaft  310  of the blade  300 . The inclined portions of each guard pole are provided below at least a part of the shearable region  350  of the blade  300 . In particular, the guard pole is arranged such that the shearable region  350  (in particular, the position of the left and right parts in the annular region) is positioned above the left inclined portion and the right inclined portion of the guard pole. The right and left parts in the annular region have more chances to cut plants than the front and rear parts. For example, as illustrated in  FIG.  3   , the front part in the annular region is cut by a width indicated by the arrow  360  is cut, but the right part in the annular region (a part on the right side as viewed from the lawn mower  10 ) is cut by a width indicated by the arrow  370  is cut, and the plants can be cut particularly efficiently at the right and left parts. Therefore, by arranging the inclined portion of the guard pole at a position corresponding to the left and right parts, it is possible to improve cutting efficiency while securing work safety. 
     The blade housing  400  is a housing provided to cover at least a part of the blade  300  from above. The blade housing  400  includes a front part  401 , a right side part  402 , a left side part  403 , and a rear part  404 . The right side part  402  and the left side part  403  extend below the front part  401  and the rear part  404 . The front part  401  and the rear part  404  are positioned slightly above the right side part  402  and the left side part  403  such that the plants in the advancing direction can be guided below the lawn mower  10 . The plurality of guard poles  211  to  214  of the guard pole portion  200  are connected to the right side part  402  and the left side part  403  of the blade housing  400 . 
     As described above, the lawn mower  10  according to the present embodiment includes the guard pole portion having the inclined portion extending in the oblique direction with respect to the machine body longitudinal direction of the lawn mower  10 . As a result, since the interval between the guard poles in the machine body longitudinal direction of the lawn mower can be widened, the plants can easily rise, and the plants can be efficiently cut. Furthermore, in a case where the guard poles are arranged in a direction parallel to the machine body longitudinal direction of the lawn mower  10 , the plants are always pushed down, and uncut parts are likely to occur. However, by providing the inclined portion, the occurrence of such uncut parts can be reduced. Therefore, it is possible to efficiently cut plants while maintaining work safety. 
     Modification Example 
     The structure of the guard pole portion  200  is not limited to the above embodiment. Any structure may be employed as long as the structure includes the inclined portion extending in the oblique direction with respect to the machine body longitudinal direction of the lawn mower  10 . For example, as illustrated in  FIG.  4   , the guard pole portion  200  in  FIG.  1    may be rotated by 180 degrees. 
     Alternatively, as in the guard pole portion  200  in  FIGS.  1  and  4   , the left inclined portion and the right inclined portion of the guard pole may be configured to be continuous in a straight line instead of an arc shape at the center part of the lawn mower  10 . That is, the left inclined portion  211   c  and the right inclined portion  211   a  of the guard pole  211  may be configured to be continuous in a state of being bent at a substantially right angle at the center part of the lawn mower  10 . 
     In the above embodiment, the example in which each of the guard poles is connected to the right side part  402  and the left side part  403  of the blade housing  400  has been described, but the present invention is not limited to this example. For example, as illustrated in  FIG.  5   , a right support portion  501  and a left support portion  502  may be attached respectively to the right side and the left side of the blade housing  400 , and each of the guard poles may be connected to the right support portion  501  and the left support portion  502 . The right support portion  501  and the left support portion  502  can be members having a thickness of, for example, approximately several cm. In this case, the height of the blade housing  400  may be the same over the entire arc. 
     As a result, a stronger connection can be made at the connection part to which the guard pole portion is connected. In particular, by providing the support portion having a larger area in the horizontal direction than the blade housing  400 , the connection area in the direction parallel to the ground can be increased, and thus a stronger connection can be realized. In addition, since the support portion may be attached to the blade housing, it is not necessary to change the shape of the blade housing at the front, rear, left, and right sides, and thus the manufacturing cost of the blade housing can be reduced. 
     In addition, although the lawn mower has been described as an example in the above-described embodiment, the structure of the above-described embodiment can be widely applied regardless of whether the lawn mower is a riding type lawn mower or a self-propelled lawn mower. The structure of the above embodiment can also be applied to other work machines (such as grass mowers) other than the lawn mowers. 
     The invention is not limited to the foregoing embodiments, and various variations/changes are possible within the spirit of the invention. 
     SUMMARY OF EMBODIMENTS 
     1. A work machine (for example, 10) according to the above embodiment includes: 
     a blade (for example,  300 ); 
     a blade housing (for example,  400 ); and 
     a guard pole portion (for example,  200 ) provided below the blade, in which 
     the guard pole portion is supported by the blade housing, and 
     the guard pole portion includes an inclined portion (for example,  211   a ,  211   c ) extending in an oblique direction with respect to a machine body longitudinal direction of the work machine. 
     Accordingly, it is possible to efficiently cut plants while maintaining work safety. 
     2. In the work machine (for example,  10 ) according to the above embodiment, 
     the inclined portion is provided below at least a part of the shearable region (for example,  350 ) of the blade. 
     In this manner, by arranging the guard pole below the shearable region of the blade, it is possible to prevent an operator and nearby people from coming into contact with the blade, and thus, it is possible to secure the work safety. 
     3. In the work machine (for example,  10 ) according to the above embodiment, 
     the guard pole portion includes a plurality of guard poles (for example,  211  to  214 ), and 
     the inclined portions of each of the guard poles are parallel to each other. 
     As a result, the interval between the guard poles becomes uniform, and thus it is possible to reduce uneven cutting of plants. 
     4. In the work machine (for example,  10 ) according to the above embodiment, 
     the inclined portion includes a left inclined portion (for example,  211   c ) and a right inclined portion (for example,  211   a ) extending in the oblique direction respectively to the left and right with respect to the machine body longitudinal direction of the work machine, and 
     the left inclined portion and the right inclined portion are continuous in an arc shape at a center of the work machine (for example,  211   b ). 
     As a result, it is possible to efficiently cut plants while improving the strength of the guard pole. 
     5. In the work machine (for example,  10 ) according to the above embodiment, 
     the left inclined portion and the right inclined portion extend obliquely backward respectively to the left and right, from a position on a center line passing through the center of the work machine and extending in the machine body longitudinal direction. 
     As a result, in a case where an obstacle such as a plant, a pebble, or a tree branch present in the advancing direction of the work machine collides with the guard pole, a force that deforms the guard pole acts. However, it is possible to improve the durability of the guard pole against the force applied in such a case. For example, even in a case where an obstacle collides with the arc portion  211   b , deformation of the guard pole  211  can be suppressed. 
     6. In the work machine (for example,  10 ) according to the above embodiment, 
     the guard pole portion includes a plurality of guard poles (for example,  211  to  214 ), and 
     the arc-shaped parts (for example,  211   b ) of each of the guard poles are concentrically arranged. 
     As a result, the interval between the guard poles becomes uniform, and thus it is possible to reduce uneven cutting of plants. 
     7. In the work machine (for example,  10 ) according to the above embodiment, 
     the guard pole portion includes a support pole portion (for example,  220 ) that supports the inclined portion. 
     As a result, rigidity of the guard pole portion can be improved, and thus deformation of the guard pole portion can be suppressed even in a case where a force is applied from the outside. 
     8. In the work machine (for example,  10 ) according to the above embodiment, 
     the support pole portion has an arc shape. 
     As a result, it is possible to efficiently cut plants left uncut on the front side of the work machine in the machine body longitudinal direction, on the rear side. 
     9. In the work machine (for example,  10 ) according to the above embodiment, 
     the support pole portion includes a plurality of support poles (for example,  221  to  224 ), and the plurality of support poles are arranged at equal intervals. 
     As a result, the interval between the support poles becomes uniform, and thus it is possible to reduce uneven cutting of plants. 
     10. In the work machine (for example,  10 ) according to the above embodiment, 
     the guard pole portion is arranged parallel to the ground. 
     Accordingly, unevenness in height of plants after cutting is reduced. 
     11. In the work machine (for example,  10 ) according to the above embodiment, 
     the oblique direction is any direction in a range of 15 degrees to 75 degrees with respect to the machine body longitudinal direction. 
     Accordingly, it is possible to more efficiently cut plants. 
     12. In the work machine (for example,  10 ) according to the above embodiment, 
     the shearable region is an annular region having a predetermined width and formed by rotation of a shearing portion of the blade about a rotary shaft (for example,  310 ) of the blade. 
     Accordingly, in the shearable region which is the annular region, the cutting efficiency can be improved. 
     13. In the work machine (for example,  10 ) according to the above embodiment, 
     the guard pole portion includes a plurality of guard poles (for example,  211  to  214 ) and a plurality of support poles (for example,  221  to  224 ), 
     the guard poles are parallel to one another, 
     each of the guard poles includes a left inclined portion (for example,  211   c ) and a right inclined portion (for example,  211   a ) extending obliquely backward respectively to the left and right with respect to the machine body longitudinal direction of the work machine, the left inclined portion and the right inclined portion are continuous in an arc shape at a center of the work machine (for example,  211   b ), the support poles have arc shapes parallel to one another, and one end of each of the support poles is connected to the left inclined portion of one guard pole (for example,  214 ) of the plurality of guard poles, and the other end is connected to the right inclined portion of the one guard pole. 
     As a result, the interval between the guard poles and the interval between the support poles become uniform, and thus it is possible to reduce uneven cutting of plants. In addition, it is possible to efficiently cut plants left uncut on the front side in the advancing direction of the work machine on the rear side where the arc-shaped support pole exists. In addition, by providing the support pole, rigidity of the guard pole portion can be improved, and thus deformation of the guard pole portion can be suppressed even in a case where a force is applied from the outside. 
     In addition, by providing the arc portion (arc-shaped part) and the left and right inclined portions extending in the left-and-right and front-and-rear directions therefrom, in a case where an obstacle such as a plant, a pebble, or a tree branch present in the advancing direction of the work machine collides with the guard pole, a force that deforms the guard pole acts. However, it is possible to improve the durability of the guard pole against the force applied in such a case. 
     14. In the work machine (for example,  10 ) according to the above embodiment, further includes: 
     a support portion (for example,  501 ,  502 ) connected to the blade housing, and 
     the guard pole portion is connected to the support portion and supported by the blade housing via the support portion. 
     As a result, a stronger connection can be made at the connection part to which the guard pole portion is connected. In addition, since the support portion may be attached to the blade housing, it is not necessary to change the shape of the blade housing at the front, rear, left, and right sides, and thus the manufacturing cost of the blade housing can be reduced. 
     According to the present invention, it is possible to efficiently cut plants while maintaining work safety.