CN117028134A - Cycloid hydraulic motor with small displacement - Google Patents

Abstract

The invention discloses a cycloid hydraulic motor with small displacement, which comprises: the flow distribution valve comprises a first end face, a side face and a second end face, wherein N oil cavities are formed in the first end face, m first oil holes and N third oil holes are formed in the second end face, m second oil holes and N fourth oil holes are formed in the side face, regulating pieces are arranged in the m first oil holes or the second oil holes, the number of the regulating pieces is N/2, and m+n=3N/4. According to the invention, through improving the structure of the flow distribution valve and matching with the regulating piece, the number of high and low cavities of the oil cavity can be changed without reducing the thickness of the rotor-stator pair, so that the purpose of reducing the motor displacement is achieved.

Description

Cycloid hydraulic motor with small displacement

Technical Field

The invention relates to the technical field of hydraulic motors, in particular to a cycloid hydraulic motor with small displacement.

Background

A hydraulic motor is an actuator of a hydraulic system that converts hydraulic pressure energy provided by a hydraulic pump into mechanical energy (torque and rotational speed) of its output shaft. Liquid is the medium that transmits forces and movements. A gerotor hydraulic motor is a type of hydraulic motor, which is a small, low-speed, high-torque hydraulic motor of an internal-meshing gerotor type.

The displacement of the cycloid hydraulic motor is related to the rotating speed, and the smaller the displacement is, the higher the rotating speed is; the greater the displacement, the lower the rotational speed. In some applications, it is desirable for gerotor hydraulic motors to have high rotational speeds, which requires a reduction in the displacement of the motor. Currently, the main way to reduce the displacement of the motor is to reduce the thickness of the rotor-stator pair, for example, when the displacement of the motor is reduced from 80cc to below 60cc, the thickness of the rotor-stator pair causes interference between transmission parts, and after the thickness of the rotor-stator pair is reduced, the overall size of the motor is reduced, which results in a reduction of rated pressure that the motor can withstand.

Disclosure of Invention

The invention aims to solve the technical problems that: how to reduce motor displacement without degrading motor performance. Therefore, the invention provides a cycloid hydraulic motor with small displacement, and the displacement of the motor can be reduced by improving the flow distribution mode of the motor.

The technical scheme adopted for solving the technical problems is as follows: a small displacement gerotor hydraulic motor comprising: the flow distribution valve comprises a first end face, a side face and a second end face, N oil cavities are formed in the first end face, m first oil holes and N third oil holes are formed in the second end face, m second oil holes and N fourth oil holes are formed in the side face, adjusting pieces are mounted in the first oil holes or the second oil holes, the number of the adjusting pieces is N/2, and m+n=3N/4.

Further, the plurality of adjusting members and one of the fourth oil holes form a distributing unit, and the plurality of distributing units are uniformly distributed along the circumferential direction of the distributing valve.

Further, the plurality of adjusting members and one of the third oil holes form a flow distribution unit, and the plurality of flow distribution units are uniformly distributed on the second end face.

Further, the adjusting member includes: the adjusting body is embedded in the second oil hole, an adjusting cavity is formed between the adjusting body and the second oil hole, and the ball is located in the adjusting cavity.

Further, the oil inlet through hole has been seted up to the one end of adjusting the main part, first chamber that holds has been seted up to the other end of adjusting the main part, the second oilhole has the second chamber that holds, the oil inlet through hole with first chamber that holds is linked together, first chamber that holds is linked together and forms jointly with the second chamber that holds the chamber.

Further, the first accommodating cavity comprises a first circulating part and a first blocking part, the diameter of the first circulating part is d1, the diameter of the first blocking part gradually decreases along the direction away from the first circulating part, the diameter of one end of the first blocking part, which is close to the first circulating part, is d1, and the diameter of one end of the first blocking part, which is far away from the first circulating part, is d2, and d2 is smaller than d1.

Further, the second accommodating cavity comprises a second circulating part and a second blocking part, the diameter of the second circulating part is d1, the diameter of the second blocking part gradually decreases along the direction away from the second circulating part, the diameter of one end, close to the second circulating part, of the second blocking part is d1, the diameter of one end, away from the second circulating part, of the second blocking part is d2, and d2 is smaller than d1.

Further, the diameter of the sphere is D, and D2 is less than D and less than D1.

Further, a first flow passage and a second flow passage are further arranged in the distributing valve, the first flow passage is used for communicating the first oil hole and the adjusting cavity, and the second flow passage is used for communicating the adjusting cavity and the oil cavity.

Further, the method further comprises the following steps: front shell, change stator pair, back lid, main shaft, universal driving shaft and connecting plate, change stator pair to be located the front shell with between the back lid, be equipped with the valve that divides flow in the back lid, the valve that divides flow pass through the transmission shaft with change stator pair and be connected, the connecting plate is located between front shell and the change stator pair, the one end of main shaft is located in the front shell, the one end of universal driving shaft is installed in the main shaft, the other end of universal driving shaft runs through the connecting plate is connected with change stator pair.

Further, the rear cover is provided with a first oil port and a second oil port, the rear cover is internally provided with a distributing pressure plate, a first cavity is formed between the distributing pressure plate and the rear cover, the first cavity is communicated with the first oil port, and the first cavity is communicated with the first oil hole.

Further, a second cavity is formed between the distributing valve and the rear cover, the second cavity is communicated with the second oil port, and the second cavity is communicated with the second oil hole.

Further, the method further comprises the following steps: the first bearing and the second bearing are sleeved on the main shaft, the first bearing is positioned in the front shell, one part of the second bearing is positioned in the front shell, and the other part of the second bearing is positioned in the connecting plate.

Further, a spacer bush is arranged between the first bearing and the second bearing, a lock nut is arranged at one end, far away from the spacer bush, of the second bearing, and the lock nut is connected with the main shaft.

Further, a retainer ring is arranged on the inner wall of the rotor-stator pair.

The invention has the beneficial effects that the number of the high and low cavities of the oil cavity can be changed without reducing the thickness of the rotor-stator pair by improving the structure of the flow distribution valve and matching with the regulating piece, thereby achieving the purpose of reducing the displacement of the motor and not reducing the bearing capacity of the radial load of the motor; the torque is not reduced while the displacement is reduced, and the total transmission power is improved.

Drawings

The invention will be further described with reference to the drawings and examples.

Fig. 1 is a cross-sectional view of a gerotor hydraulic motor of the present invention.

Fig. 2 is a side view of the dispensing valve of the present invention.

Fig. 3 is a rear view of the dispensing valve of the present invention.

Fig. 4 is a front view of the dispensing valve of the present invention.

Fig. 5 is a cross-section of a side of a dispensing valve of the present invention.

Fig. 6 is an overall schematic of the gerotor hydraulic motor of the present invention.

Fig. 7 is a sectional view of the distributing valve of the present invention (the second oil hole is filled with oil).

Fig. 8 is a sectional view of the distributing valve (the first oil hole is filled with oil) of the present invention.

Fig. 9 is a schematic structural view of the regulating member of the present invention.

Fig. 10 is a schematic view of the structure of the port plate of the present invention.

Fig. 11 is a cross-sectional view of a rotor-stator pair of the present invention.

In the figure: 1. a front shell; 2. a rotor-stator pair; 3. a rear cover; 4. a flow distribution valve; 5. a transmission shaft; 6. an adjusting member; 7. a flow distribution platen; 8. a main shaft; 9. a linkage shaft; 10. a connecting plate; 11. a first bearing; 12. a second bearing; 13. a spacer bush; 14. a lock nut; 15. a retainer ring; 16. a port plate; 21. a volume chamber; 31. a first oil port; 32. a second oil port; 33. a first cavity; 34. a second cavity; 41. a first end face; 42. a side surface; 43. a second end face; 44. a flow distribution unit; 45. a first flow passage; 46. a second flow passage; 411. an oil chamber; 421. a second oil hole; 431. a first oil hole; 4211. a second accommodation chamber; 42111. a second circulation portion; 42112. a second blocking portion; 61. an adjustment body; 62. a sphere; 63. a regulating chamber; 611. an oil inlet through hole; 612. a first accommodation chamber; 6121. a first flow-through portion; 6122. a first blocking portion; 71. a channel; 161. and a distributing port.

Detailed Description

The invention will now be described in further detail with reference to the accompanying drawings. The drawings are simplified schematic representations which merely illustrate the basic structure of the invention and therefore show only the structures which are relevant to the invention.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention. Furthermore, features defining "first", "second" may include one or more such features, either explicitly or implicitly. In the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more.

In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.

As shown in fig. 1 to 11, the small-displacement gerotor hydraulic motor of the present invention includes: the distributing valve 4, the distributing valve 4 includes a first end face 41, a side face 42 and a second end face 43, the first end face 41 is provided with N oil cavities 411, the second end face 43 is provided with m first oil holes 431 and N third oil holes 432, the side face 42 is provided with m second oil holes 421 and N fourth oil holes 422, adjusting pieces 6 are installed in the m first oil holes 431 or the second oil holes 421, and the number of the adjusting pieces 6 is N/2, wherein m+n=3n/4. The invention can change the number of the high and low cavities of the oil cavity 411 by improving the structure of the distributing valve 4 and matching with the regulating piece 6, thereby achieving the purpose of reducing the motor displacement.

When the adjusting member 6 is installed in the first oil hole 431, the second oil hole 421 has no adjusting member 6 therein. When the regulating member 6 is installed in the second oil hole 421, there is no regulating member 6 in the first oil hole 431. That is, in practice, the adjusting member 6 may alternatively be mounted in the side face 42 or in the second end face 43 of the distributing valve 4.

For example, the third oil hole 432 is directly in communication with the oil chamber 411, and the fourth oil hole 422 is also directly in communication with the oil chamber 411.

It should be noted that the mounting positions of the N/2=m adjusting members 6 are uniformly distributed according to a certain rule. For example, when the regulating member 6 is mounted on the side surface 42, the plurality of regulating members 6 and one fourth oil hole 422 form one distributing unit 44, and the plurality of distributing units 44 are uniformly distributed in the circumferential direction of the distributing valve 4. For example, when the regulating members 6 are mounted on the second end surface 43, the plurality of regulating members 6 and one third oil hole 432 form one distributing unit 44, and the plurality of distributing units 44 are uniformly distributed on the second end surface 43.

For example, the number n=12 of the oil chambers 411, the number m=6 of the first oil holes 431 and the second oil holes 421, the number N/2=6 of the regulating members 6, and 3N/4=9, i.e., n=9-6=3. Taking the example that the adjusting members 6 are installed in the second oil holes 421, two adjusting members 6 and one fourth oil hole 422 form one flow distribution unit 44, and three flow distribution units 44 are formed in total, and the overall distribution rule of the side faces 42 of the flow distribution valve 4 is "the adjusting members 6, the fourth oil holes 422, the adjusting members 6, the fourth oil holes 422". The purpose of this arrangement is to enable the 12 oil chambers 411 to be uniformly distributed in "three high and one low".

In practical use, the adjusting member 6 may be mounted on the side surface 42 or the second end surface 43, but the mounting on the second end surface 43 occupies an axial space inside the motor to some extent, so that the adjusting member 6 is preferably mounted on the side surface 42. The following will specifically describe an example in which the adjusting member 6 is mounted on the side surface 42.

It should be noted that, the conventional structure of the distributing valve in the prior art is: the first end face is provided with 12 oil cavities, the side face is provided with 6 oil holes E, the second end face is provided with 6 oil holes F, the 6 oil holes E are directly communicated with 6 oil cavities, the 6 oil holes F are directly communicated with the other 6 oil cavities, and the oil holes E, the oil holes F and the oil cavities are communicated at intervals (namely, the 12 oil cavities are distributed in a high-low mode). With the conventional structure, 6 high-pressure chambers and 6 low-pressure chambers are formed in the 12 oil chambers. By improving the structure of the distributing valve 4, 9 high-pressure cavities and 3 low-pressure cavities are formed in 12 oil cavities, and the three high-pressure cavities and the one low-pressure cavities are distributed, so that the reduction of the motor displacement can be realized.

Since the total number of oil holes on the side surface 42 and the second end surface 43 of the distributing valve 4 is 3N/4, if the arrangement of the side oil holes, the end surface oil holes and the oil chambers 411 is still in a conventional structure, the side oil holes, the end surface oil holes and the oil chambers 411 cannot be communicated one by one (if the arrangement is in a one-to-one communication mode, 18 oil chambers are needed, which leads to the increase of the overall diameter of the distributing valve). In order to solve this problem, the present invention provides an adjusting member 6 in the oil hole of the distributing valve 4 and makes structural improvement to the flow passage inside the distributing valve 4 and the oil hole C.

Specifically, the regulating member 6 includes: the adjusting body 61 and the sphere 62, wherein the adjusting body 61 is embedded in the second oil hole 421 and forms an adjusting cavity 63 with the second oil hole 421, and the sphere 62 is located in the adjusting cavity 63. An oil inlet through hole 611 is formed in one end of the adjusting body 61, a first accommodating cavity 612 is formed in the other end of the adjusting body 61, a second accommodating cavity 4211 is formed in the second oil hole 421, the oil inlet through hole 611 is communicated with the first accommodating cavity 612, and the first accommodating cavity 612 and the second accommodating cavity 4211 are communicated and jointly form the adjusting cavity 63. The distributing valve 4 is also provided with a first flow passage 45 and a second flow passage 46, the first flow passage 45 is used for communicating the first oil hole 431 with the regulating cavity 63, and the second flow passage 46 is used for communicating the regulating cavity 63 with the oil cavity 411. That is, the first oil hole 431 and the second oil hole 421 correspond to the same oil chamber 411, and thus, it is possible to eliminate the need to increase the number of oil chambers 411. However, the first oil hole 431 and the second oil hole 421 correspond to the same oil chamber 411, and it is necessary to consider how to prevent leakage of high-pressure oil when oil is introduced.

The ball 62 (e.g., a steel ball) may move within the adjustment chamber 63. When high-pressure oil is introduced into the oil inlet through hole 611, the ball 62 is pushed to the second accommodation chamber 4211 by the high-pressure oil, and at this time, the high-pressure oil may flow to the oil chamber 411 through the second flow passage 46, and the oil chamber 411 becomes a high-pressure chamber. When the first oil hole 431 is fed with high pressure oil, the high pressure oil pushes the ball 62 toward the first receiving chamber 612, and at this time, the high pressure oil may flow to the oil chamber 411 through the first flow passage 45, the second receiving chamber 4211, and the second flow passage 46, which becomes a high pressure chamber. That is, the invention can realize the increase of the number of high-pressure cavities whether the oil is fed from the end surface or the side surface by improving the inner flow passage structure of the distributing valve 4 and matching with the regulating piece 6.

For example, the first accommodating chamber 612 includes a first flow-through portion 6121 and a first blocking portion 6122, the diameter of the first flow-through portion 6121 is set to d1, the diameter of the first blocking portion 6122 gradually decreases in a direction away from the first flow-through portion 6121, the diameter of an end of the first blocking portion 6122 near the first flow-through portion 6121 is set to d1, and the diameter of an end of the first blocking portion 6122 far from the first flow-through portion 6121 is set to d2, d2 < d1. The second receiving chamber 4211 includes a second flow portion 42111 and a second blocking portion 42112, a diameter of the second flow portion 42111 is d1, a diameter of the second blocking portion 42112 gradually decreases in a direction away from the second flow portion 42111, a diameter of an end of the second blocking portion 42112 near the second flow portion 42111 is d1, and a diameter of an end of the second blocking portion 42112 remote from the second flow portion 42111 is d2, d2 < d1. The sphere 62 has a diameter D, D2 < D < D1.

That is, the ball 62 is free to move when the ball 62 is within the first flow portion 6121 or the second flow portion 42111. When the ball 62 is pushed toward the first blocking portion 6122 by the high-pressure oil, the ball 62 eventually abuts against the inner wall of the first blocking portion 6122, sealing is achieved, and the high-pressure oil is prevented from flowing out of the second oil hole 421. When the ball 62 is pushed toward the second blocking portion 42112 by the high pressure oil, the ball 62 eventually abuts against the inner wall of the second blocking portion 42112, sealing is achieved, and the high pressure oil is prevented from flowing out of the first oil hole 431. According to the invention, through structural design of the adjusting main body 61 and structural improvement of the oil hole, high-pressure oil can be prevented from leaking from the other side no matter side oil is fed or end surface oil is fed, so that the working efficiency of the motor is ensured.

Specifically, the cycloidal hydraulic motor of the present invention further comprises: front housing 1, rotor pair 2, back lid 3, main shaft 8, universal driving shaft 9 and connecting plate 10, rotor pair 2 are located between front housing 1 and the back lid 3, and distributing valve 4 is located in the back lid 3, and distributing valve 4 is connected with rotor pair 2 through transmission shaft 5, and connecting plate 10 is located between front housing 1 and rotor pair 2, and main shaft 8's one end is located front housing 1, and the one end of universal driving shaft 9 is installed in main shaft 8, and the other end of universal driving shaft 9 runs through connecting plate 10 and is connected with rotor pair 2.

For example, the rear cover 3 is provided with a first oil port 31 and a second oil port 32, the rear cover 3 is internally provided with a distributing pressure plate 7, a first cavity 33 is formed between the distributing pressure plate 7 and the rear cover 3, the first cavity 33 is communicated with the first oil port 31, and the first cavity 33 is communicated with the first oil hole 431. A second cavity 34 is formed between the distributing valve 4 and the rear cover 3, the second cavity 34 is communicated with the second oil port 32, and the second cavity 34 is communicated with the second oil hole 421. When the first oil port 31 is filled with oil, the second oil port 32 is an oil return port, and when the second oil port 32 is filled with oil, the first oil port 31 is an oil return port. The distributing pressure plate 7 is located on the right side of the distributing valve 4, and a channel 71 is arranged in the distributing pressure plate 7, and the channel 71 can be communicated with the first oil hole 431 and the first cavity 33. The left side of the distributing valve 4 is also provided with a distributing plate 16, seven distributing ports 161 are arranged on the distributing plate 16, the distributing ports 161 are communicated with the oil cavity 411, and the right end face of the distributing plate 16 is tightly attached to the first end face 41 of the distributing valve 4.

In other words, the motor structure is that the front shell 1, the connecting plate 10, the rotor-stator pair 2, the valve plate 16 and the rear cover 3 are arranged in the order from left to right, the valve 4 and the valve plate 7 are all positioned in the rear cover 3, the right end of the transmission shaft 5 is connected with the valve 4, the left end of the transmission shaft 5 is connected with the rotor of the rotor-stator pair 2, and the transmission shaft 5 penetrates through the valve plate 16. The right end of the linkage shaft 9 is connected with the rotor, and the left end of the linkage shaft 9 is connected with the main shaft 8. When the flow distribution valve 4 rotates under the drive of high-pressure oil, the rotor can be driven to swing and rotate through the transmission shaft 5, and then the rotor drives the main shaft 8 to rotate through the linkage shaft 9. A plurality of volume cavities 21 are formed between the rotor and the stator in the rotor-stator pair 2, and after high-pressure oil enters the volume cavities 21, the volume of the volume cavities 21 changes under the action of pressure, so that the rotation of the rotor is realized.

Taking 12 oil chambers 411 as an example, 9 are high-pressure chambers and 3 are low-pressure chambers, and are uniformly distributed in three-high-low along the circumferential direction of the first end face 41. When the distributing valve 4 rotates one revolution, the 7 distributing ports 161 can complete 3 high-low pressure changes, namely, a total of 7*3 =21 high-low pressure changes, namely, 21 motor volume changes. The prior art distributing valve rotates once, 7 distributing ports complete 6 high-low pressure conversion, namely 7*6 =42 high-low pressure conversion is completed in total, namely 42 motor volume conversion. 21 ≡42=50%, thus achieving halving of motor displacement. With the present configuration of the invention, a displacement of 40cc can be achieved if the motor has an existing displacement of 80 cc.

It should be noted that the present invention does not change the original size of the distributing valve 4, and only structurally improves, so that the original size of the motor is not changed and the thickness of the rotor-stator pair is not required to be reduced while the displacement of the motor is reduced. Under the condition of the same specification (for example, 40 cc), compared with the motor in the prior art (the thickness of the rotor-stator pair is reduced), the motor can bear higher strength, provide larger torque and is suitable for being applied in a high-speed scene.

Further, the motor of the present invention further comprises: the first bearing 11 and the second bearing 12 are sleeved on the main shaft 8, the first bearing 11 is positioned in the front shell 1, one part of the second bearing 12 is positioned in the front shell 1, and the other part is positioned in the connecting plate 10. A spacer bush 13 is arranged between the first bearing 11 and the second bearing 12, a lock nut 14 is arranged at one end of the second bearing 12 away from the spacer bush 13, and the lock nut 14 is connected with the main shaft 8. A retainer ring 15 is arranged on the inner wall of the rotor-stator pair 2. For example, the first bearing 11 and the second bearing 12 are tapered roller bearings.

In the existing motor structure, the first bearing 11 and the second bearing 12 are all located completely in the front shell 1, which results in smaller spacing between the two bearings and lower radial load capacity of the motor.

In the present invention, by increasing the axial dimension of the connection plate 10, disposing a part of the second bearing 12 inside the connection plate 10, the spacing between the two bearings can be increased. According to the invention, the spacer bush 13 is arranged between the two bearings, the left end and the right end of the spacer bush 13 are respectively clung to the first bearing 11 and the second bearing 12, then the locking nut 14 is arranged at the right end of the second bearing 12 to lock the whole of the first bearing 11, the spacer bush 13 and the second bearing 12, and the locking nut 14 can provide axial pretightening force. The positioning of a portion of the second bearing 12 within the web 10 has the following effect: firstly, the distance between the two bearings can be increased, and after the distance is increased, the length of the linkage shaft 9 can be also increased, so that the radial load capacity of the motor is improved; second, the second bearing 12 is located outside the front shell 1, and the assembly and maintenance of the second bearing 12 are more convenient and better in interchangeability. In addition, after increasing the axial dimension of the connection plate 10, a sensor can be conveniently installed on the connection plate 10 to monitor the output of the shaft. The retainer ring 15 can effectively avoid the occurrence of the condition that the linkage shaft 9 is out, and is beneficial to improving the stability of motor operation.

In summary, the invention can realize the change of the number of the high and low pressure cavities of the motor by improving the structure of the distributing valve 4 and matching with the adjusting piece 6, thereby realizing the reduction of the motor displacement. The structural improvement of the invention does not reduce the axial length of the whole motor, and can still ensure that the motor has higher bearing load bearing capacity. In addition, the radial load capacity of the motor can be further enhanced by increasing the distance between the two bearings, and the overall performance of the motor is greatly improved.

With the above-described preferred embodiments according to the present invention as an illustration, the above-described descriptions can be used by persons skilled in the relevant art to make various changes and modifications without departing from the scope of the technical idea of the present invention. The technical scope of the present invention is not limited to the description, but must be determined as the scope of the claims.

Claims (15)

1. A small displacement gerotor hydraulic motor comprising:

the flow distribution valve (4), the flow distribution valve (4) comprises a first end face (41), a side face (42) and a second end face (43), N oil cavities (411) are formed in the first end face (41), m first oil holes (431) and N third oil holes (432) are formed in the second end face (43), m second oil holes (421) and N fourth oil holes (422) are formed in the side face (42), adjusting pieces (6) are arranged in the first oil holes (431) or the second oil holes (421), and the number of the adjusting pieces (6) is N/2, wherein m+n=3N/4.

2. The small-displacement gerotor hydraulic motor of claim 1, characterized in that a plurality of the regulating members (6) and one of the fourth oil holes (422) form one distribution unit (44), and the plurality of distribution units (44) are uniformly distributed in the circumferential direction of the distribution valve (4).

3. A small displacement gerotor hydraulic motor according to claim 1, characterized in that a plurality of said adjusting members (6) and one of said third oil holes (432) form a distribution unit (44), and that a plurality of said distribution units (44) are evenly distributed on said second end surface (43).

4. A small displacement gerotor hydraulic motor according to claim 2, characterized in that the adjusting member (6) comprises: the oil-saving device comprises an adjusting main body (61) and a ball body (62), wherein the adjusting main body (61) is embedded in the second oil hole (421) and forms an adjusting cavity (63) with the second oil hole (421), and the ball body (62) is located in the adjusting cavity (63).

5. The small-displacement gerotor hydraulic motor of claim 4, characterized in that an oil inlet through hole (611) is provided at one end of the adjusting body (61), a first accommodating chamber (612) is provided at the other end of the adjusting body (61), the second oil hole (421) has a second accommodating chamber (4211), the oil inlet through hole (611) is communicated with the first accommodating chamber (612), and the first accommodating chamber (612) is communicated with the second accommodating chamber (4211) and jointly forms the adjusting chamber (63).

6. The small-displacement gerotor hydraulic motor of claim 5, characterized in that the first receiving chamber (612) includes a first flow-through portion (6121) and a first blocking portion (6122), a diameter of the first flow-through portion (6121) being set to d1, a diameter of the first blocking portion (6122) gradually decreasing in a direction away from the first flow-through portion (6121), a diameter of an end of the first blocking portion (6122) near the first flow-through portion (6121) being set to d1, a diameter of an end of the first blocking portion (6122) far from the first flow-through portion (6121) being set to d2, d2 < d1.

7. The small displacement gerotor hydraulic motor of claim 6, characterized in that the second receiving chamber (4211) includes a second flow portion (42111) and a second blocking portion (42112), the second flow portion (42111) having a diameter d1, the second blocking portion (42112) having a diameter that decreases gradually in a direction away from the second flow portion (42111), the second blocking portion (42112) having a diameter d1 at an end thereof adjacent to the second flow portion (42111), the second blocking portion (42112) having a diameter d2 at an end thereof distal from the second flow portion (42111), d2 < d1.

8. The small displacement gerotor hydraulic motor of claim 7, characterized in that the spheres (62) have a diameter D, D2 < D1.

9. The small-displacement cycloidal hydraulic motor according to claim 4, wherein a first flow passage (45) and a second flow passage (46) are further provided in the distributing valve (4), the first flow passage (45) is used for communicating the first oil hole (431) with the adjusting cavity (63), and the second flow passage (46) is used for communicating the adjusting cavity (63) with the oil cavity (411).

10. The small displacement gerotor hydraulic motor of claim 1, further comprising: front housing (1), change stator pair (2), back lid (3), main shaft (8), universal driving shaft (9) and connecting plate (10), change stator pair (2) be located front housing (1) with between back lid (3), be equipped with in back lid (3) and join in marriage flow valve (4), join in marriage flow valve (4) through transmission shaft (5) with change stator pair (2) and be connected, connecting plate (10) are located between front housing (1) and change stator pair (2), one end of main shaft (8) is located in front housing (1), one end of universal driving shaft (9) is installed in main shaft (8), the other end of universal driving shaft (9) runs through connecting plate (10) is connected with change stator pair (2).

11. The small-displacement cycloidal hydraulic motor according to claim 10, wherein the rear cover (3) is provided with a first oil port (31) and a second oil port (32), the rear cover (3) is internally provided with a distributing pressure disc (7), a first cavity (33) is formed between the distributing pressure disc (7) and the rear cover (3), the first cavity (33) is communicated with the first oil port (31), and the first cavity (33) is communicated with the first oil hole (431).

12. The small-displacement gerotor hydraulic motor of claim 11, characterized in that a second cavity (34) is formed between the distributing valve (4) and the rear cover (3), the second cavity (34) being in communication with the second oil port (32), the second cavity (34) being in communication with the second oil hole (421).

13. The small displacement gerotor hydraulic motor of claim 10, further comprising: the first bearing (11) and the second bearing (12) are sleeved on the main shaft (8), the first bearing (11) is located in the front shell (1), one part of the second bearing (12) is located in the front shell (1), and the other part of the second bearing (12) is located in the connecting plate (10).

14. A small displacement gerotor hydraulic motor according to claim 13, characterized in that a spacer (13) is arranged between the first bearing (11) and the second bearing (12), that one end of the second bearing (12) remote from the spacer (13) is provided with a lock nut (14), and that the lock nut (14) is connected with the main shaft (8).

15. A small displacement gerotor hydraulic motor according to claim 12, characterized in that the inner wall of the rotor-stator pair (2) is provided with a retainer ring (15).