Small-displacement hydraulic driver

Abstract

The utility model provides a small-displacement hydraulic driver which is applied to the technical field of mechanical transmission and comprises a shell, a main power shaft is mounted on the shell, and an oil distributor is fixedly mounted in an inner cavity of the shell; the main power shaft is connected to an oil distributor through a plunger pump, and an output shaft directly outputting to the outside of the shell is installed on the oil distributor. The output shaft is connected to the oil distributor through the plunger motor, and the plunger pump and the plunger motor are communicated through an oil way channel to achieve power transmission. The main power shaft is perpendicular to the output shaft, the plunger pump is perpendicular to the plunger motor, and vertical reversing of power is achieved through the oil distributor. An oil inlet cover is further arranged on the oil distributing disc, an oil inlet is formed in the oil inlet cover, a filter element is axially installed at the oil inlet in a floating mode, and a positioning spring is installed between the filter element and the inner wall of the shell. The utility model is suitable for the driver with small displacement, the whole structure is miniaturized, the follow-up installation is convenient, and the space layout is reasonable.

Description

Technical Field

[0001] The present application relates to the field of mechanical transmission technology, and in particular to a small-displacement hydraulic drive. Background Art

[0002] A hydraulic drive axle, or hydraulic actuator, is a structure that achieves power output through hydraulic drive, converting engine input power into output power. The trend in the industry is towards smaller displacement or miniaturization of hydraulic drive axles.

[0003] In 2022, the applicant applied for a Chinese invention patent with application number "202210162653.4", which discloses a zero-steering hydraulic drive axle, including a housing, in which a first drive assembly is arranged. One end of the first drive assembly is connected to an external power input device for power input, and the other end of the first drive assembly is connected to an external rotation output device for power output; the first drive assembly includes: a plunger pump and a plunger motor, one end of the plunger pump cooperates with the power input device to realize active rotation of the plunger pump, and the other end of the plunger pump is connected to an external oil pipe for oil intake or oil replenishment. The plunger motor cooperates with the rotation output device, and the plunger pump and the plunger motor are connected by an oil circuit to realize power transmission from the plunger pump to the plunger motor. The hydraulic drive axle adopts a dual-drive assembly design with the same structure, with a gear transmission group and a bidirectional output drive shaft integrated inside.

[0004] Therefore, a small-displacement hydraulic drive can be designed to meet the development needs of small displacement and miniaturization. Summary of the Invention

[0005] (1) Technical issues to be resolved

[0006] In view of this, the present application provides a small-displacement hydraulic driver suitable for small batches of drivers, whose overall structure is miniaturized to facilitate subsequent installation and layout.

[0007] (2) Technical solution

[0008] The embodiments of this specification provide the following technical solutions:

[0009] An embodiment of the present specification provides a small-displacement hydraulic drive, comprising a housing, the housing being equipped with a main power shaft connected to an external power source, and an oil separator being fixedly installed in the inner cavity of the housing; the main power shaft is connected to the oil separator via a plunger pump, and an output shaft directly output to the outside of the housing is installed on the oil separator; the output shaft is connected to the oil separator via a plunger motor, and the plunger pump and the plunger motor are connected via an oil passage to achieve power transmission; the main power shaft and the output shaft are arranged perpendicularly, and the plunger pump and the plunger motor are arranged perpendicularly, and vertical reversing of power is achieved through the oil separator; an oil inlet cover is also provided on the oil separator, and the oil inlet cover is provided with an oil inlet, and a filter element is axially floatingly installed at the oil inlet, and a positioning spring is installed between the filter element and the inner wall of the housing.

[0010] In this solution, the main power shaft transmits power to the plunger motor through the plunger pump and the oil separator, and only one set of plunger pump and plunger motor is provided; the main power shaft and the output shaft are arranged vertically, and the layout is reasonable; the output shaft is directly output to the outside of the shell through the drive of the plunger motor, and the output shaft is then connected to the external travel mechanism (such as travel wheels or tracks) through external gears or sprockets and other transmission mechanisms. The overall structure of the hydraulic drive is lightweight and suitable for small-displacement and lightweight use; in addition, the hydraulic oil entering the oil separator can be filtered through the filter element, and the oil circuit inside the oil separator can be replenished through the oil inlet; the filter element is easy to position and install, and a gap is left between the outer side of the filter element and the inner wall of the shell, and then it is positioned and installed in the shell by a positioning spring. There is no need to consider the length and size processing error of the filter element, avoiding problems such as the filter element being too long and causing the dry shell to be unable to be assembled.

[0011] In some embodiments, a bypass valve and a control valve stem for controlling the opening or closing of the valve port of the bypass valve are also provided on the oil separation plate. The bypass valve is used to control the connection or closure of the oil passage in the oil separation plate and the inner cavity of the shell; the control valve stem is rotatably installed in the shell, and the control valve stem is eccentrically provided with a downward pressure protrusion.

[0012] In this solution, the downward pressure projection controls the opening and closing of the bypass valve. The output shaft is connected to an external travel mechanism. When the main power shaft is not rotating or the plunger pump is not working, if the output shaft rotates, the hydraulic oil in the plunger motor will flow back into the oil distribution plate. In this case, the bypass valve port must remain open. When the main power shaft is rotating, the bypass valve port is closed.

[0013] In some embodiments, a drive plate connected to the control valve stem is installed on the housing, and the drive plate is used to connect to an external control console; and / or, the valve seat of the bypass valve is installed on the oil distribution plate, and a valve ball and a valve ball spring are installed at the valve port; when the control valve stem is rotated, the downward pressing protrusion contacts and presses down the valve ball to open the valve port.

[0014] In this solution, the control valve stem is fixedly connected to the drive plate; the drive plate is connected to the external control console, and the drive plate drives the downward pressure protrusion of the control valve stem to rotate, thereby pressing down the valve ball at the valve port to open the valve port. At this time, the oil circuit in the oil distribution plate is connected to the inner cavity of the shell, and the bypass valve is in an open state; the valve ball spring always pushes the valve ball to seal it against the valve port.

[0015] In some embodiments, the housing is rotatably mounted with an adjusting swash plate and a control gear lever connected to the adjusting swash plate; the plunger pump includes a first plunger cylinder connected to the oil distribution plate and a first plunger axially movably mounted in the first plunger cylinder, and the first plunger cylinder is coaxially rotatably connected to the main power shaft; the first thrust bearing at the plunger pump is mounted in the adjusting swash plate, and the inclination angle of the first thrust bearing is adjusted by rotating the adjusting swash plate.

[0016] In this solution, the first plunger cylinder is coaxially connected to the main power shaft; the adjusting swash plate is fixedly connected to the control gear lever, and the control gear lever is connected to the external control console; the adjusting swash plate can be adjusted and rotated forward and backward, thereby driving the first thrust bearing to adjust the tilt angle, so the power output of the plunger pump can be adjusted by adjusting the swash plate or even the reverse output of power (achieved by tilting the first thrust bearing forward or backward). When the side end face of the first thrust bearing is in a vertical setting, the first plunger does not produce axial displacement and does not do work; by setting the adjusting swash plate and the control gear lever, the power output and reversing of the entire hydraulic drive can be realized, realizing "stepless speed change".

[0017] In some embodiments, the plunger motor includes a second plunger cylinder connected to the oil distribution plate, a second plunger and a second thrust bearing, the second plunger cylinder is coaxially rotatably connected to the output shaft; the second thrust bearing is placed in the inner cavity of the housing.

[0018] In this solution, the second thrust bearing of the plunger motor is installed in the housing, and its inclination angle cannot be adjusted; the hydraulic power oil of the plunger pump will enter the second plunger cylinder of the plunger motor through the oil distribution plate, pushing its second plunger to axially displace and perform work, which will cause the second plunger cylinder of the plunger motor to rotate, thereby driving the rotation of the output shaft.

[0019] In some embodiments, the oil distribution plate is provided with a first end face corresponding to the plunger pump and a second end face corresponding to the plunger motor, and the first end face is perpendicular to the second end face; a first oil circuit and a second oil circuit are provided on the first end face, and a third oil circuit connected to the first oil circuit and a fourth oil circuit connected to the second oil circuit are provided on the second end face.

[0020] In this solution, the first end face must be installed in a fit with the plunger pump, and the second end must be installed in a fit with the plunger motor; the first end face and the second end face are arranged perpendicularly, so that the main power shaft and the output shaft are arranged perpendicularly to realize vertical reversal of power; through the set oil circuit, the power of the plunger pump can be transmitted to the plunger motor, and then the output shaft can be driven to rotate to realize power output.

[0021] In some embodiments, the inner cavity of the shell is sealed and filled with hydraulic oil, and the oil inlet cover is separately installed on the oil distribution plate; the oil inlet is connected to the oil passage in the oil distribution plate through a one-way valve; the hydraulic oil in the shell replenishes the internal oil circuit of the oil distribution plate through the oil inlet.

[0022] In this solution, the entire inner cavity of the shell is sealed and filled with hydraulic oil. The hydraulic oil in the inner cavity of the shell is filtered by the filter element and then enters the oil distribution plate through the oil inlet for replenishment to maintain the balance of internal and external oil pressure.

[0023] In some embodiments, the main power shaft is mounted with a drive wheel and cooling fan blades; and both the main power shaft and the output shaft are mounted with sealing oil seals. In this solution, the drive wheel transmits power from the external engine to the main power shaft, driving the main power shaft to rotate, thereby driving the plunger pump to operate.

[0024] In some embodiments, the output shaft is connected to an external travel mechanism through an external gear transmission or sprocket transmission structure; the shell is connected to an oil return pot through an oil pipe, and the oil return pot is connected to the inner cavity of the shell, and the height of the oil return pot is higher than the shell.

[0025] In this solution, the oil return pot is connected to the inner cavity of the shell, and its height is higher than the height of the shell. The purpose is that when the hydraulic drive is working, the hydraulic oil in the inner cavity of the shell will expand due to heat. Therefore, the oil return pot is set to avoid excessive oil pressure in the inner cavity affecting the service life of the drive.

[0026] In some embodiments, the inner side of the filter element is installed in the mounting cavity of the oil inlet cover through a positioning gasket, and a gap is left between the outer side of the filter element and the inner wall of the housing. The filter element is axially floated and limited by the positioning spring to position the filter element between the oil inlet cover and the inner wall of the housing.

[0027] In this solution, the filter element is limited by the positioning spring, the filter element is easy to install, and the filter element will not interfere with the installation of other components.

[0028] (3) Beneficial effects

[0029] Compared with the prior art, the beneficial effects that can be achieved by at least one of the above-mentioned technical solutions adopted in the embodiments of this specification include at least the following: the utility model is suitable for use in small-displacement drivers, the overall structure is miniaturized, the subsequent installation of the driver is convenient, and the spatial layout is reasonable; the main power shaft transmits power to the plunger motor through the plunger pump and the oil distribution plate, thereby driving the output shaft to rotate; the opening or closing of the bypass valve is controlled by the downward pressure protrusion of the control valve stem eccentricity. When the output shaft connected to the travel mechanism actively rotates and the plunger pump does not output power, the hydraulic oil in the oil distribution plate can be discharged from the bypass valve to the inner cavity of the shell through the opening of the bypass valve; by setting an adjusting inclined plate to control the inclination angle of the first thrust bearing of the plunger pump, and then adjusting the oil pressure output power of the plunger pump, the "stepless speed change" of the driver can be realized; its filter element can filter the hydraulic oil at the oil inlet, and its filter element is installed in the shell by a positioning spring, which is easy to install and will not interfere with the installation of other components. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0031] Figure 1 is a stereogram in this application;

[0032] Figure 2 is a cross-sectional view in this application;

[0033] Figure 3 This application Figure 2 AA cross-sectional view;

[0034] Figure 4 This application Figure 2 BB cross-sectional view;

[0035] Figure 5 This is a three-dimensional diagram after removing the shell in this application;

[0036] Figure 6 It is a three-dimensional diagram of the relevant part of the oil inlet cap in this application;

[0037] Figure 7 It is a three-dimensional diagram of the oil distribution tray and the oil inlet cover in this application;

[0038] Figure 8 It is an exploded view of the filter screen and positioning spring in this application;

[0039] Figure 9 is an exploded view of the bypass valve and control valve stem in this application;

[0040] Figure 10 It is a three-dimensional diagram of the adjustment swash plate and the control gear lever in this application;

[0041] Figure 11 It is a three-dimensional diagram of the plunger pump and the main power shaft in this application;

[0042] Figure 12 is a perspective view of the plunger motor and output shaft in this application;

[0043] Among them: 1 is the housing, 2 is the main power shaft, 3 is the oil distribution plate, 4 is the plunger pump, 5 is the output shaft, 6 is the plunger motor, 7 is the oil inlet cover, 8 is the filter element, 9 is the positioning spring, 10 is the bypass valve, 11 is the control valve stem, 12 is the drive plate, 13 is the adjustment swash plate, 14 is the control gear lever, 15 is the oil return pot, 201 is the drive wheel, 202 is the heat dissipation fan blade, 301 is the first end face, 302 is the second end face, 303 is the first oil circuit, 304 is the second oil circuit, 305 is the third oil circuit, 306 is the fourth oil circuit, 401 is the first plunger cylinder, 402 is the first plunger, 403 is the first thrust bearing, 601 is the second plunger cylinder, 602 is the second plunger, 603 is the second thrust bearing, 701 is the oil inlet, 702 is the mounting cavity, 1001 is the valve port, 1002 is the valve seat, 1003 is the valve ball, 1004 is the valve ball spring, and 1101 is the downward pressure protrusion. DETAILED DESCRIPTION

[0044] The specific embodiments of the present invention are described in further detail below in conjunction with the accompanying drawings and examples. The following examples are intended to illustrate the present invention but are not intended to limit the scope of the present invention. In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the present invention can be practiced without these specific details.

[0045] Combine Figures 1-12 As shown, the present application provides a small-displacement hydraulic drive, including a shell 1, on which is installed a main power shaft 2 connected to an external power source, and an oil distribution plate 3 is fixedly installed in the inner cavity of the shell 1; the main power shaft 2 is connected to the oil distribution plate 3 through a plunger pump 4, and the oil distribution plate 3 is installed with an output shaft 5 that is directly output to the outside of the shell 1; the output shaft 5 is connected to the oil distribution plate 3 through a plunger motor 6, and the plunger pump 4 and the plunger motor 6 are connected through an oil channel to realize power transmission; wherein the main power shaft 2 and the output shaft 5 are arranged vertically, the plunger pump 4 and the plunger motor 6 are arranged vertically, and the power reversal is realized through the oil distribution plate 3.

[0046] like Figure 6As shown, the oil distributor 3 is also provided with an oil inlet cap 7 having an oil inlet port 701. A filter element 8 is axially mounted in a floating manner at the oil inlet port 701, with a positioning spring 9 installed between the filter element 8 and the inner wall of the housing 1. The filter element 8 filters the hydraulic oil entering the oil distributor 3, and the oil inlet port 701 allows oil to be replenished to the oil circuit within the oil distributor 3 to maintain oil pressure balance.

[0047] The main power shaft 2 of this embodiment transmits power to the plunger motor 6 through the plunger pump 4 and the oil distribution plate 3, thereby driving the output shaft 5 to rotate. The overall layout is reasonable and the structure is lightweight, suitable for small-displacement and lightweight use.

[0048] In some embodiments, as Figure 1 、 Figure 2 and Figure 11 As shown, the main power shaft 2 is mounted with a drive wheel 201 and cooling fan blades 202. Oil seals are also mounted on both the main power shaft 2 and the output shaft 5. In this embodiment, the drive wheel 201 transmits power from the external engine to the main power shaft 2, driving the main power shaft 2 to rotate, which in turn drives the plunger pump 4.

[0049] In some embodiments, as Figure 4 、 Figure 6 and Figure 9 As shown, the oil distribution plate 3 is also provided with a bypass valve 10 and a control valve stem 11 for controlling the opening or closing of the valve port 1001 of the bypass valve 10. The bypass valve 10 is used to control the connection or closure of the oil passage in the oil distribution plate 3 and the inner cavity of the shell 1; the control valve stem 11 is rotatably installed in the shell 1, and the control valve stem 11 is eccentrically provided with a downward pressure protrusion 1101, which is used to control the opening or closing of the valve port 1001 of the bypass valve 10.

[0050] It should be noted that the number and installation position of the bypass valve are not limited. When the main power shaft 2 rotates, the valve port 1001 of the bypass valve 10 is closed.

[0051] Among them, such as Figure 6 and Figure 9 As shown, a driving piece 12 connected to the control valve stem 11 is installed on the housing 1. The driving piece 12 is used to connect to an external control console. The driving piece 12 drives the downward pressing protrusion 1101 of the control valve stem 11 to rotate, thereby pressing down the valve ball 1003 at the valve port 1001, so that the valve port 1001 is opened. At this time, the oil circuit in the oil distribution plate 3 is connected to the inner cavity of the housing 1, and the bypass valve 10 is in the open state; Figure 4 and Figure 9As shown, the valve seat 1002 of the bypass valve 10 is installed on the oil distribution plate 3, and the valve ball 1003 and the valve ball spring 1004 are installed at the valve port 1001. The valve ball spring 1004 always pushes the valve ball 1003 to seal it against the valve port 1001; the control valve stem 11 is rotated, and the downward pressing protrusion 1101 contacts and presses down the valve ball 1003 to open the valve port 1001.

[0052] When the output shaft 5 actively rotates, and the main power shaft 2 does not rotate or the plunger pump 4 does not work, if the output shaft 5 rotates, the hydraulic oil in the plunger motor 6 will react to the oil distribution plate 3. At this time, the valve port 1001 of the bypass valve 10 needs to be always in an open state so that the hydraulic oil in the oil distribution plate 3 can be discharged from the valve port 1001.

[0053] In some embodiments, as Figure 2 、 Figure 5 and Figure 10 As shown, the housing 1 is rotatably mounted with an adjusting swash plate 13 and a control gear lever 14 connected to the adjusting swash plate 13; Figure 11 As shown, the plunger pump 4 includes a first plunger cylinder body 401 connected to the oil distribution plate 3 and a first plunger 402 axially movably installed in the first plunger cylinder body 401, and the first plunger cylinder body 401 is coaxially connected to the main power shaft 2; the first thrust bearing 403 at the plunger pump 4 is installed in the adjusting swash plate 13, and the inclination angle of the first thrust bearing 403 is adjusted by rotating the adjusting swash plate 13. The adjusting swash plate 13 can be adjusted and rotated forward and backward, thereby driving the first thrust bearing 403 to adjust the inclination angle. Therefore, the power output of the plunger pump 4 or even the reverse output of power (achieved by tilting the first thrust bearing 403 forward or backward) can be adjusted by adjusting the swash plate 13.

[0054] It should be pointed out that when the side end face of the first thrust bearing 403 is in a vertical setting, the first piston 402 does not produce axial displacement and does not perform work; by setting the adjusting swash plate 13 and the operating gear lever 14, the power output and reversing of the entire hydraulic drive can be realized, realizing "stepless speed change".

[0055] In some embodiments, as Figure 3 and Figure 12 As shown, the plunger motor 6 includes a second plunger cylinder 601, a second plunger 602 and a second thrust bearing 603. The second plunger cylinder 601 is coaxially connected to the output shaft 5 for rotation; the second thrust bearing 603 is placed in the inner cavity of the housing 1, and its inclination angle cannot be adjusted.

[0056] It should be noted that springs are provided in both the first plunger 402 and the second plunger 602 .

[0057] In some embodiments, as Figure 7As shown, the oil distribution plate 3 is provided with a first end face 301 corresponding to the plunger pump 4 and a second end face 302 corresponding to the plunger motor 6, and the first end face 301 is perpendicular to the second end face 302; a first oil circuit 303 and a second oil circuit 304 are provided on the first end face 301, and a third oil circuit 305 connected to the first oil circuit 303 and a fourth oil circuit 306 connected to the second oil circuit 304 are provided on the second end face 302. Through the above-mentioned oil circuits, the power of the plunger pump 4 can be vertically reversed and transmitted to the plunger motor 6, thereby driving the output shaft 5 to rotate, thereby realizing power output.

[0058] In some embodiments, the inner cavity of the housing 1 is sealed and filled with hydraulic oil, and the oil inlet cover 7 is separately installed on the oil distribution plate 3; Figure 4 As shown, the oil inlet 701 is connected to the oil channel in the oil distribution plate 3 through a one-way valve; the hydraulic oil in the housing 1 replenishes the internal oil circuit of the oil distribution plate 3 through the oil inlet 701.

[0059] In some embodiments, the output shaft 5 is connected to an external traveling mechanism (such as a traveling wheel or a crawler) through an external gear transmission or sprocket transmission structure. Figure 1 As shown, the housing 1 is connected to an oil return pot 15 through an oil pipe. The oil return pot 15 is connected to the inner cavity of the housing 1, and the height of the oil return pot 15 is higher than the housing 1. When the hydraulic drive is working, the hydraulic oil in the inner cavity of the housing 1 expands due to heat and can be discharged to the oil return pot 15.

[0060] In some embodiments, as Figure 2 and Figure 6 As shown, the inner side of the filter element 8 is mounted in the mounting cavity 702 of the oil inlet cap 7 via a positioning washer. A gap is left between the outer side of the filter element 8 and the inner wall of the housing 1. The filter element 8 is axially floatingly limited by a positioning spring 9, positioning the filter element 8 between the oil inlet cap 7 and the inner wall of the housing 1. The installation and positioning of the filter element 8 are convenient. The use of the positioning spring 9 to position the filter element 8 does not interfere with the assembly of other parts. A gap is left between the outer side of the filter element 8 and the inner cavity of the housing 1. Therefore, the length dimensional error of the filter element 8 does not affect the assembly of other parts. For example, if the filter element 8 is too long, it will prevent the housing 1 from sealing together, causing interference.

[0061] In this specification, the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the embodiments described later, the description is relatively simple, and the relevant parts can be referred to the partial description of the previous embodiments.

[0062] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A small-displacement hydraulic driver, comprising a housing (1), wherein the housing (1) is provided with a main power shaft (2) connected to an external power source, and an oil distribution plate (3) is fixedly installed in the inner cavity of the housing (1); characterized in that: The main power shaft (2) is connected to the oil distribution plate (3) via a plunger pump (4), and an output shaft (5) is mounted on the oil distribution plate (3) for directly outputting to the outside of the housing (1); the output shaft (5) is connected to the oil distribution plate (3) via a plunger motor (6), and the plunger pump (4) and the plunger motor (6) are connected via an oil channel to achieve power transmission; The main power shaft (2) and the output shaft (5) are arranged vertically, and the plunger pump (4) and the plunger motor (6) are arranged vertically, and vertical reversal of power is achieved through the oil separation plate (3); an oil inlet cover (7) is also provided on the oil separation plate (3), and the oil inlet cover (7) is provided with an oil inlet port (701), and a filter element (8) is axially floatingly installed at the oil inlet port (701), and a positioning spring (9) is installed between the filter element (8) and the inner wall of the housing (1).

2. The small displacement hydraulic driver according to claim 1, characterized in that: The oil distribution plate (3) is also provided with a bypass valve (10) and a control valve stem (11) for controlling the opening or closing of a valve port (1001) of the bypass valve (10). The bypass valve (10) is used to control the connection or closing of the oil passage in the oil distribution plate (3) and the inner cavity of the housing (1). The control valve stem (11) is rotatably mounted in the housing (1), and the control valve stem (11) is eccentrically provided with a downward pressing protrusion (1101).

3. The small displacement hydraulic driver according to claim 2, characterized in that: A drive plate (12) connected to the control valve stem (11) is installed on the housing (1), and the drive plate (12) is used to be connected to an external control console; and / or, the valve seat (1002) of the bypass valve (10) is installed on the oil distribution plate (3), and a valve ball (1003) and a valve ball spring (1004) are installed at the valve port (1001); when the control valve stem (11) is rotated, the downward pressing protrusion (1101) contacts and presses down the valve ball (1003) to open the valve port (1001).

4. The small displacement hydraulic driver according to claim 1, characterized in that: The housing (1) is rotatably mounted with an adjusting swash plate (13) and a control gear lever (14) connected to the adjusting swash plate (13); the plunger pump (4) comprises a first plunger cylinder (401) connected to the oil distribution plate (3) and a first plunger (402) axially movably mounted in the first plunger cylinder (401), the first plunger cylinder (401) being coaxially rotatably connected to the main power shaft (2); a first thrust bearing (403) at the plunger pump (4) is mounted in the adjusting swash plate (13), and the inclination angle of the first thrust bearing (403) is adjusted by rotating the adjusting swash plate (13).

5. The small displacement hydraulic driver according to claim 1, characterized in that: The plunger motor (6) comprises a second plunger cylinder (601) connected to the oil distribution plate (3), a second plunger (602) and a second thrust bearing (603); the second plunger cylinder (601) is coaxially rotatably connected to the output shaft (5); and the second thrust bearing (603) is disposed in the inner cavity of the housing (1).

6. The small displacement hydraulic driver according to claim 1, characterized in that: The oil distribution plate (3) is provided with a first end surface (301) corresponding to the plunger pump (4) and a second end surface (302) corresponding to the plunger motor (6), wherein the first end surface (301) is perpendicular to the second end surface (302); a first oil circuit (303) and a second oil circuit (304) are provided on the first end surface (301), and a third oil circuit (305) communicating with the first oil circuit (303) and a fourth oil circuit (306) communicating with the second oil circuit (304) are provided on the second end surface (302).

7. The small displacement hydraulic driver according to claim 1, characterized in that: The inner cavity of the housing (1) is sealed and filled with hydraulic oil, and the oil inlet cover (7) is separately installed on the oil distribution plate (3); the oil inlet (701) is connected to the oil passage in the oil distribution plate (3) through a one-way valve, and the hydraulic oil in the housing (1) replenishes the internal oil circuit of the oil distribution plate (3) through the oil inlet (701).

8. The small displacement hydraulic driver according to claim 1, characterized in that: A driving wheel (201) and a heat dissipation fan blade (202) are installed on the main power shaft (2); and a sealing oil seal is installed on both the main power shaft (2) and the output shaft (5).

9. The small displacement hydraulic driver according to claim 1, characterized in that: The output shaft (5) is connected to an external travel mechanism; the housing (1) is connected to an oil return pot (15) via an oil pipe, the oil return pot (15) is connected to the inner cavity of the housing (1), and the height of the oil return pot (15) is higher than the housing (1).

10. The small displacement hydraulic driver according to claim 1, characterized in that: The inner side of the filter element (8) is installed in the installation cavity (702) of the oil inlet cover (7) through a positioning gasket, and a gap is left between the outer side of the filter element (8) and the inner wall of the housing (1). The filter element (8) is axially floated and limited by the positioning spring (9), so that the filter element (8) is positioned between the oil inlet cover (7) and the inner wall of the housing (1).

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