Patent Publication Number: US-2021190048-A1

Title: Handheld high-pressure cleaning machine

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 15/518,205, filed on Jul. 23, 2018, which is a national stage of International Application No. PCT/CN2016/106663, filed on Nov. 21, 2016. The International Application claims priority to Chinese Patent Application No. 201510810513.3, filed on Nov. 20, 2015. All of the afore-mentioned patent applications are hereby incorporated by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     The present application relates to a handheld high-pressure cleaning machine, and in particular, to a handheld high-pressure cleaning machine using the pump unit. 
     BACKGROUND 
     In family life and outdoor activities, there are always extensive demands for cleaning. 
     In courtyard-centered family life, people usually need to clean balconies, aisles, outdoor tables and chairs, barbecues, automobiles, bicycles, garages, pets, garden tools, windows, swimming pools, outdoor stairs, and the like. Those objects are used outdoors. Therefore, it is inevitable for those objects to get stains such as oil, leaves, and dust. It is very inconvenient to clean by using a duster cloth, and those objects need to be cleaned by using water or even high-pressure water. To satisfy the foregoing demands, a solution on the market is to provide domestic high-pressure cleaning machines. As disclosed in the Chinese patent CN1840246A, the high-pressure cleaning machines generally have a main body and a spray gun. The main body is provided with a water tank, a motor, and a water pump. The spray gun is provided with a trigger switch for spraying water. The high-pressure cleaning machines have a large volume and a heavy weight. When a working scenario is changed, transportation of the high-pressure cleaning machines is inconvenient. For example, on a family cleaning day, if windows, lanes, stairs, and automobiles need to be cleaned one by one, a high-pressure cleaning machine needs to be moved among different locations. In addition, water needs to be added to a water tank before the high-pressure cleaning machine is used. Operations are not simple enough. 
     In outdoor activities, such as mountain climbing, off-road driving, cycling, camping, horse riding, and boat sailing, tools and animals involved in the fierce activities that are carried out in an environment closer to nature get dirty more easily and need to be cleaned in time. For example, automobiles, motorcycles, and bicycles inevitably get mud after being used in the wild. Ships, boats, and rafts are covered with mud and water plants, and also need to be cleaned after sailing. Horses and users sweat and get dirty, and should be washed or take a shower in time in case of uncomfortableness. The foregoing high-pressure cleaning machine is not suitable to be carried around in the foregoing outdoor activities due to a large volume and a heavy weight. The foregoing high-pressure cleaning machine is powered by using an alternating-current power source. A matching power source is difficult to find in the outdoor activities. Users have no choice but to tolerate stains in the activities, and clean after they return to a fixed location after the activities end; or the users simply wipe with a duster cloth when passing by a water source during the activities. Cleaning efficiency is low, an effect is poor, and it is very dirty in a cleaning process. 
     In conclusion, users have a cleaning demand in various scenarios and locations. However, related products on the market have poor portability, and can only be used in limited scenarios and locations. The users cannot clean anytime anywhere. If a product that can be conveniently and effortlessly moved to clean a balcony, a lane, an automobile, and the like in various family cleaning activities and can be carried around in activities such as off-road driving and cycling to satisfy a cleaning demand in outdoor activities while satisfying a domestic cleaning demand of the users can be provided, cleaning work of the users will be greatly simplified, and a location range of the cleaning work will be expanded, thereby improving life quality of the users. 
     A main reason affecting a portable function of a high-pressure cleaning machine is mainly that a pump in the high-pressure cleaning machine has a relatively large volume and a relatively heavy weight. A common structure of the pump is shown in the Chinese patent CN1212899C. The pump is driven to work by using a piston and an oscillating wheel-disk. The oscillating wheel-disk and the piston need a relatively large quantity of working cavities. Therefore, this type of pump has a relatively complex structure, a relatively heavy weight, and a relatively large volume. 
     A main reason affecting an outdoor use function of a high-pressure cleaning machine is that the high-pressure cleaning machine uses an alternating-current power source. The high-pressure cleaning machine that is powered by using an alternating current is limited by a power supply, and a use scenario needs to be provided with a corresponding alternating-current power source, thereby reducing convenience of application in an outdoor scenario. The high-pressure cleaning machine that is powered by using an alternating current is limited by a length of a power line, and a cleaning range thereof is only within a range of the length of the power line, thereby restricting the cleaning range and mobility of the high-pressure cleaning machine. 
     SUMMARY 
     In one aspect, a handheld high-pressure cleaning machine is provided. The handheld high-pressure cleaning machine is powered by direct current, and connectable to an external water source using a water pipe; wherein the handheld high-pressure cleaning machine comprises a spray gun comprising: a housing, wherein a motor and a pump driven by the motor are provided in the housing; a handle having a front end and a rear end with the front end of the handle formed on or connected to the housing; a detachable rechargeable battery pack coupled externally to the handle; and a nozzle connected to a water outlet of the pump whereby water from the external water source may be sprayed out through the nozzle; wherein the pump comprises a central chamber, a water inlet, a water outlet and a single plunger, a water inlet chamber connected to the water inlet, and a water outlet chamber connected to the water outlet, and wherein the plunger is disposed in the central chamber and is driven by the motor to perform reciprocating motion in the central chamber, and wherein the water inlet chamber and the water outlet chamber are located at one side of the plunger closer to the nozzle, and the external water source enters the water inlet chamber through the water inlet, is discharged from the water outlet chamber after being pressurized by the central chamber, and is sprayed outward through the nozzle. 
     In another aspect, a handheld high-pressure cleaning machine is provided. The handheld high-pressure cleaning machine is powered by direct current, and connectable to an external water source using a water pipe; wherein the handheld high-pressure cleaning machine comprises a spray gun comprising: a housing, wherein a motor, a transmission mechanism connected to the motor, and a pump driven by the transmission mechanism are provided in the housing; a handle having a front end and a rear end with the front end of the handle formed on or connected to the housing; a detachable rechargeable battery pack coupled externally to the handle; and a nozzle connected to a water outlet of the pump whereby water from the external water source may be sprayed out through the nozzle; wherein the pump comprises a central chamber, a water inlet, a water outlet and a single plunger, a water inlet chamber connected to the water inlet, and a water outlet chamber connected to the water outlet, and wherein the plunger is disposed in the central chamber and is driven by the motor to perform reciprocating motion in the central chamber. 
     In yet another aspect, a handheld high-pressure cleaning machine without a water tank is provided. The handheld high-pressure cleaning machine is powered by direct current, and connectable to an external water source using a water pipe; wherein the handheld high-pressure cleaning machine comprises a spray gun comprising: a housing, wherein a motor, a transmission mechanism connected to the motor, and a pump driven by the transmission mechanism are provided in the housing; a handle having a front end and a rear end with the front end of the handle formed on or connected to the housing; a detachable rechargeable battery pack coupled externally to the handle; and a nozzle connected to a water outlet of the pump whereby water from the external water source may be sprayed out through the nozzle; wherein the pump comprises a central chamber, a water inlet, a water outlet and a single plunger, a water inlet chamber connected to the water inlet, and a water outlet chamber connected to the water outlet, and wherein the plunger is disposed in the central chamber and is driven by the motor to perform reciprocating motion in the central chamber, and wherein the water inlet chamber and the water outlet chamber are located at one side of the plunger, and the external water source enters the water inlet chamber through the water inlet, is discharged from the water outlet chamber after being pressurized by the central chamber, and is sprayed outward through the nozzle. 
     Compared with the prior art, a beneficial effect of the present application may be as follows: The plunger in the pump applied to the high-pressure cleaning machine is driven by the eccentric mechanism or the crank-link mechanism to perform reciprocating motion in a chamber so as to perform high-pressure water pumping. Therefore, a structure of the pump is relatively simple, and there is only one plunger, so that power consumption is reduced compared with a multi-plunger structure. In addition, a volume of the high-pressure cleaning machine using this type of pump is relatively small. 
     Compared with the prior art, a beneficial effect of the present application may be as follows: Locations of the pump, the transmission mechanism, the motor, and the battery pack are properly arranged, thereby effectively improving handholding comfort of the high-pressure cleaning machine. 
     Compared with the prior art, a beneficial effect of the present application may be as follows: The output speed of the motor is transferred to the pump after being reduced by the transmission mechanism, thereby effectively balancing a speed range required by the pump and a weight of the motor, and further reducing the total weight of the high-pressure cleaning machine. Preferably, the transmission mechanism uses the planetary gear reduction structure. The planetary gear reduction structure can not only effectively reduce the output speed of the motor and improve the output torque of the motor, but also have characteristics of a small volume and a light weight, thereby further improving handholding comfort of the high-pressure cleaning machine. 
     Compared with the prior art, a beneficial effect of the present application may be as follows: The high-pressure cleaning machine uses a direct-current battery pack for power supplying, and can be connected to the external water source by using the water pipe, thereby effectively improving portability of the high-pressure cleaning machine, and expanding use scenarios of the high-pressure cleaning machine. A user can use the high-pressure cleaning machine for cleaning work in any scenario with a water source. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The objectives, the technical solutions, and the beneficial effects of the present application that are described above can be clearly obtained with reference to descriptions of the accompanying drawings and by using detailed descriptions of the following specific embodiments that can implement the present application. 
       Same numerals and symbols in the accompanying drawings and the specification are used to represent same or equivalent elements. 
         FIG. 1  is a schematic diagram of a high-pressure cleaning machine according to an embodiment of the present application; 
         FIG. 2  is a specific structural diagram of the high-pressure cleaning machine shown in  FIG. 1 ; 
         FIG. 3  is a schematic diagram of a high-pressure cleaning machine according to another embodiment of the present application; 
         FIG. 4  is an overall schematic diagram of a pump, a transmission mechanism, and a motor according to an embodiment of the present application; 
         FIG. 5  is an exploded schematic diagram of the pump, the transmission mechanism, and the motor in  FIG. 4 ; 
         FIG. 6  a cross-sectional view of the pump in  FIG. 4  along a section line AA, where a plunger is in a first critical state; 
         FIG. 7  a cross-sectional view of the pump in  FIG. 4  along a section line 
       AA, where a plunger is in a second critical state; 
         FIG. 8  is a cross-sectional view of the pump in  FIG. 4  along a section line BB; 
         FIG. 9  is a cross-sectional view of the pump in  FIG. 4  along a section line CC; 
         FIG. 10  is a schematic diagram of an embodiment of a transmission mechanism of a high-pressure cleaning machine; 
         FIG. 11  is a schematic diagram of another embodiment of a transmission mechanism of a high-pressure cleaning machine; 
         FIG. 12  is a schematic diagram of another embodiment of a transmission mechanism of a high-pressure cleaning machine; 
         FIG. 13  is a schematic diagram showing that a pump is connected to a plunger by using a crank-link mechanism according to an embodiment of the present application, where the plunger is in a first critical state; 
         FIG. 14  is a schematic diagram showing that a pump is connected to a plunger by using a crank-link mechanism according to an embodiment of the present application, where the plunger is in a second critical state; 
         FIG. 15  is a schematic diagram of a pump structure according to a second embodiment of the present application; and 
         FIG. 16  is a schematic diagram of the pump structure in  FIG. 15  from another angle of view. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Preferred embodiments of the present application are described below in detail with reference to the accompanying drawings to make a person skilled in the art easily understand advantages and features of the present application. Therefore, the protection scope of the present application is more clearly defined. 
     As shown in  FIG. 1 ,  FIG. 1  is a schematic diagram of a high-pressure cleaning machine  1  according to an embodiment of the present application. The high-pressure cleaning machine  1  is handheld and has a handle used for holding. The high-pressure cleaning machine  1  has a housing  10 . A motor  2 , a transmission mechanism  3  connected to the motor  2 , and a pump  4  driven by the transmission mechanism  3  are provided in the housing  10 . The high-pressure cleaning machine  1  may be powered by using alternating current or direct current. To satisfy a requirement of handholding and portability, the high-pressure cleaning machine  1  does not have a water tank configured to store water, but instead, is connected to an external water source by using a water pipe. The external water source may be a pond, a water tap, or the like. The high-pressure cleaning machine  1  further has a nozzle  11 . The water in the external water source is sprayed out through the nozzle  11  after being pressurized by the pump. This type of handheld high-pressure cleaning machine has a small volume and a light weight, and is easy to operate. 
     As shown in  FIG. 2 ,  FIG. 2  is a specific structural diagram of the high-pressure cleaning machine  1  shown in  FIG. 1 . In this embodiment, the left side of  FIG. 2  is defined as the front direction, and the right side of  FIG. 2  is defined as the rear. 
     The high-pressure cleaning machine is a handheld high-pressure cleaning machine powered by using direct current. The high-pressure cleaning machine  1  is an integrated spray gun, including a handle  106  used for holding, a battery pack  9 , the motor  2 , the transmission mechanism  3  connected to the motor  2 , the pump  4  driven by the transmission mechanism  3 , the nozzle  11  connected to a water outlet of the pump  4 , and a water inlet port  104  connected to a water inlet of the pump  4 . The high-pressure cleaning machine  1  further includes the housing  10  accommodating the motor  2 , the pump  4 , and the transmission mechanism  3 . The handle  106  is formed on or is connected to the housing  10 . A trigger component  105  is disposed near the handle  106 , is specifically a trigger, and is configured to trigger a spraying action. The pump, the transmission mechanism, and the motor form a functional component of the high-pressure cleaning machine. 
     Referring to  FIG. 2 , as described above, the high-pressure cleaning machine  1  does not include a water tank, but instead, is connected to a water pipe  14  at the water inlet port  104 , and then is connected to an external water source  16  by using the water pipe  14 . In this way, after the water inlet port  104  is connected to the water pipe  14 , in a family activity, a user can hold the high-pressure cleaning machine and freely move in a length range of the water pipe to do spraying and cleaning work only by connecting a tail end of the water pipe to a water tap or putting the tail end into an external water source such as a swimming pool, a pond, or a bucket. In an outdoor activity, a user can do spraying and cleaning work only by stopping at a place with water, and putting the tail end of the water pipe into an external water source at any time. The pump can suck water in the external water source into the high-pressure cleaning machine, and then directly spray the water out of the high-pressure cleaning machine. 
     To be carried around and used to clean various articles, the high-pressure cleaning machine  1  needs to have a light weight and a high cleaning capability. However, the two are contradictory. To implement a light weight of the high-pressure cleaning machine, weights of the battery pack  9  and the functional component need to be reduced as much as possible. However, a light weight of the battery pack  9  shortens a working time of the high-pressure cleaning machine, and a light weight of the functional component lowers cleaning efficiency of the high-pressure cleaning machine. As a result, a cleaning capability is reduced. Moreover, the working time and the cleaning efficiency are mutually restricted. For a same battery pack, a longer working time indicates a weaker cleaning capability. On the contrary, a stronger cleaning capability indicates a shorter working time. Therefore, in this embodiment, the weight, the working time, and the cleaning efficiency of the high-pressure cleaning machine need to be balanced. 
     In this embodiment, the high-pressure cleaning machine  1  has a total weight less than or equal to 3 kilograms. In an optional implementation solution, the total weight is less than 2.8 kilograms, 2.5 kilograms, 2 kilograms, 1.8 kilograms, 1.7 kilograms, or 1.5 kilograms. In an embodiment, the functional component has a weight less than or equal to 1000 grams, and the battery pack  9  has a weight less than or equal to 800 grams. In another optional embodiment, the functional component has a weight less than or equal to 600 grams, and the battery pack  9  has a weight less than or equal to 400 grams. In an embodiment, another component except the functional component and the battery pack  9  has a weight less than or equal to 500 grams. Preferably, the another component has a weight less than 400 grams or 300 grams. A lighter weight enables that the high-pressure cleaning machine 1 to be handheld to do cleaning work for a long time. In this embodiment, the battery pack  9  is a lithium battery pack of a rated voltage of 18 V to 42 V and of 1.5 Ah to 3 Ah, to provide enough working energy and be light. In another optional embodiment, the rated voltage of the battery pack may also be from 28 V to 60 V. In an embodiment, the battery pack  9  is a detachable rechargeable battery pack. The battery pack may be at least adaptively connected to two different types of direct-current tools, so that different direct-current tools can share the battery pack, so as to reduce types and a quantity of battery packs required by a user 
     The motor  2 , the transmission mechanism  3 , and the pump  4  are described in detail below. A specific structure thereof has both a light weight and a cleaning capability. 
     In addition to the weight, a location of the center of gravity also affects actual weight experience of a user. In this embodiment, the pump  4 , the transmission mechanism  3 , and the motor  2  in the functional component are sequentially arranged from front-to-rear direction, and are located at one end of the handle  106 . The battery pack  9  is located at the other end of the handle  106 , so that the center of gravity of the functional component is located in the front of a front endpoint of the handle, and the center of gravity of the battery pack is located behind the front endpoint of the handle. In an optional implementation solution, at least one part of the functional component and the battery pack  9  that are respectively located at the two ends of the handle  106  extends into the handle  106 . In an optional implementation solution, all or some of the pump  4 , the transmission mechanism  3 , and the motor  2  in the functional component are disposed in parallel to the handle  106 . For example, the pump  4  is located at one end the handle  106 , and the transmission mechanism  3  and the motor  2  are disposed in parallel to the handle  106 . 
     The functional component and the battery pack  9  are two main weight bodies of the high-pressure cleaning machine  1 . The functional component and the battery pack  9  are respectively arranged at the two ends of the handle  106 , so that the center of gravity of the high-pressure cleaning machine  1  is located near the handle  106 . Therefore, when a user holds the high-pressure cleaning machine, the weight basically falls onto a hand of the user. It is relatively labor-saving. Specifically, the center of gravity of the high-pressure cleaning machine  1  falls in a front-to-rear direction of the high-pressure cleaning machine and is within a range from 8 centimeters behind a rear endpoint of the handle  106  to 8 centimeters in front of a front endpoint of the handle  106 . In an optional embodiment, the center of gravity falls in the front-to-rear direction of the high-pressure cleaning machine  1  and is within a range from the rear endpoint of the handle  106  to 5 centimeters, 3 centimeters, 2 centimeters, or 1 centimeter in front of the front endpoint of the handle  106 . In another optional embodiment, the center of gravity falls in the front-to-rear direction of the high-pressure cleaning machine  1  and is within a range from 5 centimeters, 3 centimeters, 2 centimeters, or 1 centimeter behind the rear endpoint of the handle  106  to the front endpoint of the handle  106 . In another optional embodiment, the center of gravity falls in the front-to-rear direction of the high-pressure cleaning machine  1  and is within a range from the rear endpoint of the handle  106  to the front endpoint of the handle. 
     In this embodiment, the handle  106  is obliquely arranged. In another optional embodiment, the handle  106  is basically vertically arranged. In this embodiment, the handle  106  is located at the tail of an entire machine. In another optional embodiment, the handle  106  may be located in the middle of the entire machine. 
     In this embodiment, the water inlet port  104  is located near the center of gravity, and specifically, is located within a range of 5 centimeters or 3 centimeters in front of or behind the center of gravity. In this way, a weight of the water pipe  14  connected to the water inlet port also falls near the center of gravity. The water inlet port  104  may also be located near the handle  106 , and specifically, is within a range from 3 centimeters or 5 centimeters in front of the front endpoint of the handle  106  to 3 centimeters or 5 centimeters behind the rear endpoint. In this way, a probability that the water pipe  14  intertwines with another object when a user moves is reduced. 
     To improve portability, in this embodiment, the high-pressure cleaning machine  1  has a total length less than 500 millimeters. Preferably, the total length is 400 millimeters or 350 millimeters. When nozzles of different lengths are used, the total length of the high-pressure cleaning machine is changed. For example, when a long nozzle is used, the total length of the high-pressure cleaning machine may reach 1000 millimeters. Preferably, when no nozzle is added to the high-pressure cleaning machine  1 , the length of the high-pressure cleaning machine  1  is less than 300 millimeters or 250 millimeters. The high-pressure cleaning machine  1  has a total height less than 250 millimeters or 200 millimeters, and a total width (not including the battery pack) less than 150 millimeters or 100 millimeters. 
       FIG. 3  shows a high-pressure cleaning machine  1  according to another embodiment of the present application. The high-pressure cleaning machine  1  has a main body  12  and a spray gun  13  that are separately disposed. The spray gun  13  is used for a handholding operation. The spray gun  13  is provided with a nozzle  11 . The spray gun  13  is connected to the main body  12  by using a water pipe  14 . A motor  2 , a transmission mechanism  3 , and a pump  4  are disposed in the main body  12 . In a preferred embodiment, the main body  12  further includes a water tank  15 . The water tank  15  can store some water. In this way, the high-pressure cleaning machine  1  can work in a place far away from a water source. Water in the water tank  15  is delivered to the spray gun  13  through the water pipe  14  after being pressurized by the pump  4 . A user controls the spray gun  13  to point to a to-be-cleaned object to clean. 
     The high-pressure cleaning machines  1  in the foregoing different embodiments all have the pump  4 , the motor  2 , and the transmission mechanism  3  connected the motor  2  and the pump  4 , as shown in  FIG. 4 , and  FIG. 5 . The motor  2  is a common AC motor or DC motor. The motor  2  has a motor shaft  21  rotating around an axis of the motor. The motor shaft  21  outputs rotational power to the exterior. To ensure air-tightness, the transmission mechanism  3  generally has a transmission housing  30  externally wrapping the transmission mechanism  3 . The transmission housing  30  has two openings. One opening enables the transmission mechanism  3  to connect to the motor  2 . The other opening enables the transmission mechanism  3  to connect to the pump  4 . The pump  4  is driven by the motor  2  by using the transmission mechanism  3  to increase water pressure of water entering the pump  4 , thereby improving a cleaning effect of water. 
     As shown in  FIG. 4 , the pump  4  has a housing  46  wrapping a periphery of the pump. The housing  46  has a sealed casing, and a water inlet  431 , a water outlet  441 , and a connection port connected to the transmission mechanism  3  are on a surface of the housing  46 . The water inlet  431  is configured to connect to an external water source, a water pipe, or a water gun. Water enters the pump  4  from the water inlet  431 . Preferably, there is one water inlet  431 . After being pressurized in the pump  4 , water is discharged from the water outlet  441 . The water outlet  441  is generally connected to the nozzle  11  of the high-pressure cleaning machine  1 . In this way, the nozzle  11  may spray pressurized water out. To avoid mutual interference of water inlet and outlet, generally, the water inlet  431  and the water outlet  441  are separately disposed. Preferably, there is one water outlet  441 . For convenience of assembly, the housing  46  includes a pump body  461  and an upper pump cover  462  and a lower pump cover  463  that are detachably installed on the pump body  461 . The upper pump cover  462  and the lower pump cover  463  are symmetrically installed at two sides of the pump body  461 . The upper pump cover and the lower pump cover are fixedly connected to the pump body  461  in a common fixing manner, for example, by using bolts. The water inlet  431  and the water outlet  441  are both installed on the pump body  461 , and opening directions of the water outlet  431  and the water inlet  441  are mutually perpendicular. Certainly, in another implementation manner, the housing  46  may be integrally formed or may be formed by assembling multiple parts familiar to a person skilled in the art. 
     A specific structure of the pump in this embodiment is described in detail below. 
     As shown in  FIG. 5  and  FIG. 6 , in the housing  46 , the pump  4  has a plunger  5 . The plunger  5  is configured to pressurize water. The plunger  5  is a cylinder extending along a length direction. As can be seen with reference to  FIG. 5  and  FIG. 6 , an extension direction of a length of the plunger  5  is separately perpendicular to an opening direction of the water inlet  431  and an opening direction of the water outlet  441 . The plunger  5  may be driven to perform reciprocating motion along the length direction of the plunger  5 . In this embodiment of the present application, the plunger  5  is installed and connected to an eccentric mechanism  7 . One the one hand, the eccentric mechanism  7  is connected to the plunger  5 , and on the other hand, the eccentric mechanism  7  is fixedly connected to the transmission mechanism  3 . Therefore, the plunger  5  is driven by the motor  2  and the transmission mechanism  3  by using the eccentric mechanism  7 , and actually performs eccentric reciprocating motion. The center of the eccentric reciprocating motion is a rotation center of the transmission mechanism  3 , and a direction of the rotation center is perpendicular to the extension direction of the length of the plunger  5 . Therefore, from the angle of the extension direction of the length of the plunger  5 , that is, a direction of an arrow OO′ shown in  FIG. 6 , the plunger  5  is driven by the motor  2  and the transmission mechanism  3  to perform linear reciprocating motion. 
     As shown in  FIG. 6 , there is a central chamber  41  in the pump  4 . The central chamber  41  is hollow. The plunger  5  is preferably accommodated in the central chamber  41 . The central chamber  41  extends along the length direction of the plunger  5 . A size of the central chamber  41  along the length direction of the plunger  5  is greater than the length of the plunger  5 , so that when the plunger  5  performs reciprocating motion in the direction, the central chamber  41  always has a cavity  42 . As shown in  FIG. 6 , when the plunger  5  moves to a lower end of the central chamber  41 , the cavity  42  is located at an upper end of the central chamber  41 . As shown in  FIG. 7 , when the plunger  5  moves to the upper end of the central chamber  41 , the cavity  42  is located at the lower end of the central chamber  41 . 
     As shown in  FIG. 8  and  FIG. 9 , the pump  4  further has a water inlet chamber  43  and a water outlet chamber  44  that are separated from the central chamber  41 . The water inlet chamber  43  is connected to the water inlet  431 . The water inlet  431  is configured to connect to an external water source, a water pipe, or a water tap. External water enters the water inlet chamber  43  through the water inlet  431 . The water outlet chamber  44  is connected to the water outlet  441 . High-pressure water obtained after pressurization is discharged from the water outlet  441 , and enters the nozzle  11 . The water inlet chamber  43  and the water outlet chamber  44  are disposed in parallel. In this embodiment, the water inlet chamber  43 , the water outlet chamber  44 , and the central chamber  41  are connected to each other, and a through connection channel is formed. External water enters the water inlet chamber  43 , and is eventually discharged from the central chamber  41  through the water outlet chamber  44 . In the central chamber  41 , water is pressurized by the plunger  5  to form high-pressure cleaning water whose pressure is greater than the atmospheric pressure. The water inlet chamber  43  includes a first water inlet chamber  432  and a second water inlet chamber  433  that are symmetrically disposed. Water entering from the water inlet  431  may selectively enter the first water inlet chamber  432  or the second water inlet chamber  433 . The central chamber  41  is separately connected to the first water inlet chamber  432  and the second water inlet chamber  433 . In this embodiment, the first water inlet chamber  432  is connected to one end of the central chamber  41 , and the second water inlet chamber  433  is connected to the opposite other end of the central chamber  41 . The pump  4  further includes connection channels  45  that enable the central chamber  41  to separately connect to the two water inlet chambers, as shown in  FIG. 9 . In this embodiment, a connection channel  45  configured to connect to the first water inlet chamber  432  is disposed at one end of the central chamber  41 , and a connection channel  45  configured to connect to the second water inlet chamber  433  is disposed at the other end of the central chamber  41 . An extension direction of the connection channel  45  is perpendicular to an extension direction of the central chamber  41 . 
     The water outlet chamber  44  has the water outlet  441 , and the water outlet chamber  44  also includes a first water outlet chamber  442  and a second water outlet chamber  443  that are symmetrically disposed. The first water outlet chamber  442  and the second water outlet chamber  443  are also separately connected to the central chamber  41 , and are both connected to the water outlet  441 . In this embodiment, the opening direction of the water inlet  431  is perpendicular to the opening direction of the water outlet  441 . The first water outlet chamber  442  and the second water outlet chamber  443  are respectively connected to opposite ends of the central chamber  41 . Further, the first water outlet chamber  442  and the second water outlet chamber  443  are also connected to the central chamber  41  by using connection channels  45 . That is, a connection channel  45  at one end of the central chamber  41  connects the first water inlet chamber  432  and the first water outlet chamber  442  to the central chamber  41 . A connection channel  45  located at the other end of the central chamber  41  connects the second water inlet chamber  433  and the second water outlet chamber  443  to the central chamber  41 . The water inlet chamber  43 , the water outlet chamber  44 , and the central chamber  41  are disposed in parallel. Connecting channels  45  respectively connected to the water inlet chamber  43  and the water outlet chamber  44  are disposed at an end portion  47  of the central chamber  41 . 
     As shown in  FIG. 4  and  FIG. 9 , most of the water inlet chamber  43 , the water outlet chamber  44 , and the central chamber  41  are located in the pump body  461 . The upper pump cover and the lower pump cover have respective depressions for forming the end portion  47  of the central chamber  41 . When the upper pump cover and the lower pump cover are installed on the pump body  461 , the complete central chamber  41  is formed. The upper pump cover  462  and the lower pump cover  463  are further provided with connection channels  45 . The connection channels  45  are configured to respectively connect the water inlet chamber  43  and the water outlet chamber  44  to the central chamber  41 . 
     In the present application, the pump  4  further includes a one-way valve unit  6  configured to control flowing of water in a channel. The one-way valve unit  6  includes a first one-way valve unit  61  and a second one-way valve unit  62  that are symmetrically disposed. The first one-way valve unit  61  is used as an example for description below. In this embodiment, the first one-way valve unit  61  includes a first one-way valve component  611  that is disposed between the first water inlet chamber  432  and the central chamber  41  and a second one-way valve component  612  that is disposed between the central chamber  41  and the first water outlet chamber  442 . The first one-way valve component  611  is configured to control flowing of water between the first water inlet chamber  432  and the central chamber  41 . The second one-way valve component  612  is configured to control flowing of water between the first water outlet chamber  442  and the central chamber  41 . When the first one-way valve component  611  is opened, water in the first water inlet chamber  432  may flow to the central chamber  41 . Moreover, water in the central chamber  41  does not flow to the first water inlet chamber  432  because of a unidirectional conduction function of the one-way valve component. That is, the first one-way valve component  611  controls water to flow only from the first water inlet chamber  432  to the central chamber  41 . When the first one-way valve component  611  is closed, water in the first water inlet chamber  432  cannot flow to the central chamber  41 . In this case, the first water inlet chamber  432  and the central chamber  41  are separated from each other. Similarly, when the second one-way valve component  612  is opened, water in the central chamber  41  may flow to the second water outlet chamber  443 . The second one-way valve component  612  has a unidirectional conduction function. When the second one-way valve component  612  is closed, water in the central chamber  41  cannot flow to the second water outlet chamber  443 , and the water gathers in the central chamber  41 . 
     In the present application, the plunger  5  in the central chamber  41  is configured to control opening and closing of the first one-way valve unit  61 . Particularly, the plunger  5  may control the first one-way valve component  611  to be opened, and simultaneously control the second one-way valve component  612  to be closed. The plunger  5  may further control the first one-way valve component  611  to be closed, and simultaneously control the second one-way valve component  612  to be opened. That is, the plunger  5  may simultaneously control the first one-way valve component  611  and the second one-way valve component  612  to be in different states of being opened or closed. As shown in the figure, it is defined that when moving to a lower-most end of the central chamber  41 , the plunger  5  is in a first critical state. In this state, the plunger  5  starts moving from the lower-most end to an upper end. In this case, the first one-way valve component  611  is opened, while the second one-way valve component  612  is closed. Therefore, water flows from the first water inlet chamber  432  to the central chamber  41 , and does not flow out of the central chamber  41 . The water gathers in the central chamber  41 . Then, the plunger  5  continues moving from the lower-most end of the central chamber  41  to the upper end, and moves to an upper-most end of the central chamber  41 . It is defined that the plunger  5  is in a second critical state in this case. In the second critical state, the plunger  5  starts moving from the upper-most end to the lower end. In this case, the first one-way valve component  611  is closed, while the second one-way valve component  612  is opened. Water cannot be supplemented from the water inlet chamber  43  and enter the central chamber  41 . Water originally in the central chamber  41  is squeezed by the plunger  5  to generate high pressure, flows to the first water outlet chamber  442 , and is sprayed out from the nozzle  11  through the water outlet  441 . 
     Similarly, the plunger  5  may also control opening and closing of the second one-way valve unit  62 . The second one-way valve unit  62  includes a third one-way valve component  621  and a fourth one-way valve component  622 . The third one-way valve component  621  is disposed between the second water inlet chamber  433  and the central chamber  41 , and the fourth one-way valve component  622  is disposed between the central chamber  41  and the second water outlet chamber  443 . When the plunger  5  is in the first critical state, the third one-way valve component  621  is closed while the fourth one-way valve component  622  is opened. Therefore, water in the central chamber  41  flows out of the second water outlet chamber  443 . When the plunger  5  is in the second critical state, the third one-way valve component  621  is opened while the fourth one-way valve component  622  is closed. Therefore, water flows from the second water inlet chamber  433  to the central chamber  41 . Therefore, the second one-way valve unit  62  and the first one-way valve unit  61  can be complementary, thereby improving efficiency of pumping water by the pump. In a process in which the plunger  5  is changed from the first critical state to the second critical state, water entering from the water inlet  431  enters the central chamber  41  through the first water inlet chamber  432 , and is discharged from the second water outlet chamber  443  from the water outlet  441  with squeezing of the plunger  5 . In a process in which the plunger  5  is changed from the second critical state to the first critical state, water entering from the water inlet  431  enters the central chamber  41  through the second water inlet chamber  433 , and is discharged from the first water outlet chamber  442  from the water outlet  441  with squeezing of the plunger  5 , and is sprayed out from the nozzle  11 . 
     The first one-way valve component  611  includes a one-way valve  613  and a biasing component  614  for biasing the one-way valve  613 . When the plunger  5  is in the second critical state, the biasing component  614  generates a biasing force so that the one-way valve  613  seals the first water inlet chamber  432 . As the plunger  5  is changed from the second critical state to the first critical state, a cavity volume near the one-way valve  613  gradually increases. Therefore, pressure generated to overcome the biasing component  614  becomes increasingly high. Eventually, the one-way valve  613  is opened, that is, the first one-way valve component  611  is changed from a closed state to an opened state. The second one-way valve component  612  also includes a one-way valve  615  and a biasing component  616  for biasing the one-way valve  615 . A direction of the one-way valve  615  of the second one-way valve component  612  and a biasing direction of the biasing component  616  are opposite to a direction of the one-way valve  613  of the first one-way valve component  611  and a biasing direction of the biasing component  614 . Therefore, as the plunger  5  is changed from the second critical state to the first critical state, pressure that can be generated to overcome the biasing component  616  becomes increasingly low. Eventually, the one-way valve  615  seals the first water outlet chamber  442  under the action of the biasing pressure. That is, the second one-way valve component  612  is changed from an opened state to a closed state. 
     Because the first one-way valve unit  61  and the second one-way valve unit  62  are symmetrically disposed, in a process in which the plunger  5  is changed from the second critical state to the first critical state, the third one-way valve component  621  of the second one-way valve unit  62  is correspondingly changed from an opened state to a closed state, and the fourth one-way valve component  622  is correspondingly changed from a closed state to an opened state. 
     As shown in  FIG. 6 , at a side perpendicular to the length direction of the plunger  5 , the plunger  5  has a mounting portion  50  configured to install the eccentric mechanism  7 . In this embodiment, the mounting portion  50  is a depressed cavity having an inward depression. Moreover, the mounting portion  50  is located in the center of the plunger  5 . The eccentric mechanism  7  is fixed in the mounting portion  50  by using a mounting bearing  71 . A fixed installation manner is not limited to using the mounting bearing  71 , but may also include common manners such as flat-square fitting and spline fitting. Certainly, a person skilled in the art may figure out that the eccentric mechanism  7  and the plunger  5  may also be integrally formed. The eccentric mechanism  7  includes an eccentric shaft  72  and a rotating shaft  33  connected to the eccentric shaft  72 . In this embodiment, the eccentric shaft  72  and the rotating shaft  33  are fixedly connected, and a connection manner may be integral formation. The center of the rotating shaft  33  and the center of the eccentric shaft  72  are relatively eccentrically disposed. The rotating shaft  33  is provided with a support bearing  34  having a function of supporting the rotating shaft  33 . As can be seen from  FIG. 6 , eccentricity between the center of the rotating shaft  33  and the center the eccentric shaft  72  is d. The transmission mechanism  3  drives the rotating shaft  33  to rotate around the center of the rotating shaft  33 . The eccentric shaft  72  drives, by using the mounting portion  50  and the mounting bearing  71 , the plunger  5  to rotate around the center of the eccentric shaft  72 . The eccentricity d exists between the rotating shaft  33  and the eccentric shaft  72 ; therefore, the plunger  5  performs eccentric rotating motion relative to the rotating shaft  33 . 
     The transmission mechanism  3  in this embodiment is shown in  FIG. 6 . The transmission mechanism  3  is gear drive. The transmission mechanism  3  includes a small gear  31  connected to a motor shaft  21  and a big gear  32  engaged with the small gear  31 . The big gear  32  is fixedly connected to the rotating shaft  33 . In this embodiment, the rotating shaft  33  and the motor shaft  21  are disposed in parallel. The motor shaft  21  drives, by means of a engaged driving function of the big gear  32  and the small gear  31 , the rotating shaft  33  to rotate around the center of the motor shaft  21 . The eccentric shaft  72  is fixedly connected to the rotating shaft  33 . Therefore, the eccentric shaft  72  also rotates around the center of the rotating shaft  33 . Therefore, the eccentric shaft  72  drives the plunger  5  to rotate around the center of the rotating shaft  33 . Therefore, the motor  2  can drive the plunger  5  to perform eccentric motion. In this embodiment, the motor  2  drives the plunger  5  to move by using a first-stage gear. 
     In another embodiment shown in  FIG. 10 , the transmission mechanism  3  includes a first bevel gear  351  connected to the motor shaft  21  and a second bevel gear  352  on the rotating shaft  33 . The first bevel gear  351  and the second bevel gear  352  drive in an engaged manner. The motor shaft  21  and the rotating shaft  33  are perpendicularly disposed. The plunger  5  and the mounting portion  50  are configured to fixedly connect to the eccentric shaft  72  that is eccentrically disposed relative to the rotating shaft  33 . With cooperation of the first bevel gear  351  and the second bevel gear  352 , the motor  2  drives the plunger  5  to perform eccentric motion. In this embodiment, the motor  2  drives the plunger  5  to move by using a first-stage bevel gear. 
     In another embodiment shown in  FIG. 11 , the motor  2  drives, by means of multi-stage gear drive, the plunger  5  to move. In this embodiment, the transmission mechanism  3  includes an intermediate shaft  36  and the rotating shaft  33  drive-connected to the intermediate shaft  36 . The intermediate shaft  36  and the motor shaft  21  are disposed in parallel. The intermediate shaft  36  is drive-connected to the motor shaft  21  by using a first-stage gear  361 . The rotating shaft  33  is not directly connected to the motor shaft  21 . The rotating shaft  33  is drive-connected to the intermediate shaft  21  by using a second-stage gear  362 . On the other hand, the rotating shaft  33  and the plunger  5  are eccentrically connected, which is similar to that in the foregoing embodiments. The rotating shaft  33  and the intermediate shaft  36  are disposed in parallel. An advantage of using this structure is that a drive ratio of the first-stage gear to the second-stage gear may be changed, thereby adjusting a drive output of the plunger  5 . 
     In another embodiment shown in  FIG. 12 , the transmission mechanism  3  further includes a reduction box  37 . The reduction box  37  is provided with sun and planetary gear group. The motor shaft  21  and the rotating shaft  33  are separately drive-connected to the reduction box  37 . An advantage of disposing the reduction box  37  is that a drive output of the plunger  5  can be further adjusted. 
     In the foregoing embodiments, the plunger  5  is connected to the eccentric mechanism  7 . The plunger  5  is driven by eccentric rotating motion of the eccentric mechanism  7  to perform linear reciprocating motion along the length direction of the plunger  5 . Certainly, the present application is not limited to that the plunger  5  is connected to the eccentric mechanism  7 . The plunger  5  may also be connected to another mechanism to implement linear reciprocating motion along the length direction of the plunger  5 . In embodiments shown in  FIG. 13  and  FIG. 14 , the plunger  5  is connected to a crank-link mechanism  8 . The crank-link mechanism  8  includes a connecting rod  81  and a crank  82  that are connected to each other. One end of the connecting rod  81  is connected to the crank  82 , and the other end of the connecting rod  81  is connected to the plunger  5 . One end of the crank  82  is connected to the connecting rod  81 , and the other end of the crank  82  is connected to the transmission mechanism  3 . A connection part between the connecting rod  81  and the crank  82  forms a pivot point  83 , so that the connecting rod  81  and the crank  82  can relatively move around the pivot point  83 . As shown in  FIG. 13  and  FIG. 14 , the crank-link mechanism  8  can convert rotating motion of the transmission mechanism  3  to reciprocating motion in the length direction of the plunger  5 .  FIG. 13  shows that under the action of the crank-link mechanism  8 , the plunger  5  is in the first critical state.  FIG. 14  shows that the plunger  5  is in the second critical state. 
     In embodiments shown in  FIG. 15  and  FIG. 16 , the pump  4  has a driving gear  51  connected to the transmission mechanism  3  and a driven gear  52  engaged with the driving gear  51 . The pump  4  further includes a first chamber  53  and a second chamber  54  that are respectively disposed at corresponding two sides of the driving gear  51 . The first chamber  53  and the second chamber  54  are separated by the driving gear  51  and the driven gear  52 . The first chamber  53  is connected to the water inlet  431 . The second chamber  54  is connected to the water outlet  441 . Gaps between gears of the driving gear  51  or the driven gear  52  form a delivery chamber  55  for accommodating water. As shown in  FIG. 15 , a rotation direction of the driving gear  51  is clockwise, and a rotation direction of the driven gear  52  is correspondingly counterclockwise. As the driving gear  51  rotates, the delivery chamber  55  is connected to the first chamber  53 . Water in the first chamber  53  enters the delivery chamber  55 , and flows to the second chamber  54 . In a rotation process of the driving gear  51 , a casing inner wall  48  of the pump  4  has a sealing function for the delivery chamber  55 . Therefore, water in the delivery chamber  55  does not flow out. When the driving gear  51  rotates to a connecting location between the delivery chamber  55  and the second chamber  54 , water in the delivery chamber  55  enters the second chamber  54 , and is eventually discharged from the water outlet  441 . To improve delivery efficiency, water in the first chamber  53  may further enter the delivery chamber  55  of the driven gear  52 , and is delivered to the second chamber  54  by using the driven gear  52 . An advantage of using this type of pump is that an entire structure is more compact. 
     As shown in a schematic cross-sectional view in  FIG. 16 , the transmission mechanism  3  includes a transmission shaft  38  drive-connected to the motor shaft  21 . The transmission shaft  38  is drive-connected to the motor shaft  21  by means of gear engagement. The transmission shaft  38  and the motor shaft  21  are disposed in parallel. The transmission shaft  38  is provided with the support bearing  34 . The transmission shaft  38  is connected to the driving gear  51  along an extension direction of an axis of the transmission shaft  38 . The motor  2  rotates and drives the transmission shaft  38  to rotate. The transmission shaft  38  drives the driving gear  51  and the driven gear  52  to rotate. In a rotation process of the driving gear  51  and the driven gear  52 , water may flow from the first chamber  53  to the second chamber  54 . By means of this mechanism, the transmission mechanism  3  and the pump  4  may be integrally disposed, thereby further reducing an entire volume and size. 
     As described above, in one or more implementation solutions of the transmission mechanism  3 , a speed reduction structure such as a planetary gear mechanism is included. When an input rotation speed range of the pump and a matching rotating-reciprocating conversion structure is constant, compared with using a low-speed motor whose output speed is within the input rotation speed range, entire weights and volumes of the motor and the transmission mechanism can be remarkably reduced by properly using the speed reduction structure and a high-speed motor. In this embodiment, a no-load speed of the motor  2  is greater than or equal to 10000 rpm, 12000 rpm, 15000 rpm, or 20000 rpm. A no-load output speed of the speed reduction structure of the transmission mechanism  3  is less than or equal to 3000 rpm, 2500 rpm, 2200 rpm, or 2000 rpm. A reduction ratio of the speed reduction structure of the transmission mechanism  3  is from 12:1 to 3:1, for example, approximately 10:1, 8:1, 7:1, 6:1, 5:1, or 4:1. Compared with directly using a low-speed motor, the volume and the weight of the motor  2  in this embodiment can be reduced to less than half, thereby improving portability of the high-pressure cleaning machine  1 . 
     The embodiments described above are merely some implementation manners of the present application. The descriptions thereof are relatively specific and detailed. However, it should not be understood as a limitation to the patent scope of the present application. It should be noted that, a person of ordinary skill in the art may further make some variations and improvements without departing from the concept of the present application, and the variations and improvements shall fall within the protection scope of the present application.