Hydraulic variable piston pump and electro-hydraulic servo system

Abstract

The present invention belongs to the technical field of servo mechanisms, and specifically discloses a hydraulic variable piston pump and an electro-hydraulic servo system. The hydraulic variable piston pump includes a housing, a distribution plate, a rotating cylinder assembly and a variable assembly. The distribution plate is provided with an oil suction channel and an oil discharge channel; the rotating cylinder assembly includes a transmission shaft, a cylinder body and a plunger, the transmission shaft is rotatably arranged in the installation cavity, the cylinder body and the transmission shaft rotate synchronously to make the plunger cavity selectively connected with the oil suction channel and the oil discharge channel, and the plunger is arranged in the plunger cavity; the variable assembly includes a feedback plunger, an elastic variable mechanism and a swash plate, the feedback plunger and the elastic variable mechanism are located on the same side of the swash plate, the swash plate can swing back and forth along the axial direction of the transmission shaft to apply a force along the axial direction of the transmission shaft to the plunger to achieve variable. The present invention can solve the problem that the hydraulic variable piston pump in the electro-hydraulic servo system occupies a large installation space and is heavy.

Description

Technical Field

[0001] The invention belongs to the technical field of servo mechanisms, and in particular relates to a hydraulic variable plunger pump and an electro-hydraulic servo system. Background Art

[0002] The hydraulic variable piston pump is the power element in the electro-hydraulic servo system, especially the high-speed and high-pressure variable piston pump, which is the "heart" of the integrated electro-hydraulic servo system.

[0003] At present, the hydraulic variable piston pump is installed on the outside of the system structure and is connected to the servo system by a flange. It occupies a large installation space, has a complex structure and is heavy, making it difficult to meet the development needs of miniaturization, lightweight, integration and high specific power of the integrated hydraulic system. Summary of the invention

[0004] The object of the present invention is to provide a hydraulic variable piston pump and an electro-hydraulic servo system to solve the problem that the hydraulic variable piston pump in the electro-hydraulic servo system in the prior art occupies a large installation space and is heavy.

[0005] In order to achieve the above object, according to one aspect of the present application, a hydraulic variable piston pump is provided, comprising:

[0006] A housing, wherein the housing is arranged to form a mounting cavity;

[0007] A distribution plate, wherein a fixed cover of the distribution plate is arranged at the first end of the housing, and an oil suction channel and an oil discharge channel are arranged on the distribution plate;

[0008] A rotating cylinder assembly, the rotating cylinder assembly comprising a transmission shaft, a cylinder body and a plunger, the transmission shaft being rotatably disposed in the mounting cavity and extending out of the housing, the cylinder body being provided with a plunger cavity, the cylinder body being sleeved on the transmission shaft and synchronously rotating with the transmission shaft so that the plunger cavity is selectively connected with the oil suction channel and the oil discharge channel, the plunger being disposed in the plunger cavity and being reciprocating along the axial direction of the transmission shaft; and

[0009] A variable component, the variable component includes a feedback plunger, an elastic variable mechanism and a swash plate, the feedback plunger and the elastic variable mechanism are located on the same side of the swash plate, the swash plate is arranged in the mounting cavity and reciprocates along the axial direction of the transmission shaft under the action of the feedback plunger and the elastic variable mechanism to apply a force to the plunger along the axial direction of the transmission shaft.

[0010] Furthermore, the rotating cylinder assembly also includes a return plate, which is arranged in the mounting cavity and located at the end of the cylinder away from the distribution plate, and the end of the plunger close to the return plate is movably connected to the return plate, and the inclined plate is installed on the outer casing through an ear shaft and reciprocates along the axial direction of the transmission shaft.

[0011] Furthermore, the rotating cylinder assembly also includes a ball head sleeve, a mounting sleeve is provided on the cylinder body, the mounting sleeve is coaxially arranged with the transmission shaft, the ball head sleeve is fixedly sleeved on the mounting sleeve, and the return plate is rotatably connected to the cylinder body through the ball head sleeve.

[0012] Furthermore, the rotating cylinder assembly also includes a plurality of adjusting washers with different thicknesses, and the plurality of adjusting washers can be selectively sleeved on the mounting sleeve and located at an end of the ball head sleeve away from the swash plate.

[0013] Further, a positioning groove is provided on the inner wall of the installation cavity, the depth direction of the positioning groove is parallel to the axial direction of the transmission shaft, the elastic variable mechanism comprises a sleeve and an elastic member, the sleeve is buckled in the positioning groove, and one end of the sleeve abuts against the swash plate, and the two ends of the elastic member abut against the bottom of the positioning groove and the bottom of the sleeve respectively;

[0014] The housing is provided with a channel, and the channel is communicated with the feedback plunger;

[0015] The hydraulic variable displacement piston pump further includes a variable displacement control valve which is remotely connected to the housing through the passage.

[0016] Furthermore, the transmission shaft extends along the length direction of the housing, and two ends of the transmission shaft are rotatably connected to the distribution plate and the housing respectively.

[0017] Further, the second end of the housing is provided with a through hole communicating with the installation cavity, and the transmission shaft extends from the through hole to the outside of the housing;

[0018] The hydraulic variable piston pump also includes a sealing assembly, which is arranged on the housing to seal the through hole. The sealing assembly includes a sealing cover, a sealing column and a fastener. The sealing column is integrated with the sealing cover, and the fastener is used to fix the sealing cover to the housing.

[0019] Furthermore, a side of the cylinder body close to the distribution plate is provided with an escape space, a limiting step is provided on the transmission shaft, the transmission shaft passes through the escape space, and the limiting step stops inside the escape space;

[0020] The rotating cylinder assembly also includes a first limit member, a second limit member and an elastic element. The first limit member is sleeved on the transmission shaft and is located on the side of the limit step close to the distribution plate. The second limit member is fixedly arranged on the cylinder body and is located on the inner wall of the avoidance space. The elastic element is arranged between the first limit member and the second limit member.

[0021] Furthermore, at least one connecting hole is provided on the shell, and the connecting hole is communicated with the installation cavity.

[0022] On the other hand, the present invention further provides an electro-hydraulic servo system, which includes the above-mentioned hydraulic variable piston pump.

[0023] By applying the technical solution of the present invention, since the core components of the variable assembly, namely the elastic variable mechanism and the feedback plunger, are arranged on the same side of the swash plate, the structure is more compact, the structural space of the hydraulic variable plunger pump can be reasonably utilized, the volume and weight of the hydraulic variable plunger pump can be reduced, and it is easier to realize the miniaturization and lightweight design of the hydraulic variable plunger pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0025] Figure 1 is an exploded view of a hydraulic variable piston pump disclosed in an embodiment of the present application;

[0026] Figure 2 is a cross-sectional view in a first direction of the hydraulic variable piston pump disclosed in an embodiment of the present application;

[0027] Figure 3 is a cross-sectional view of the hydraulic variable piston pump disclosed in the embodiment of the present application in the second direction;

[0028] Figure 4 It is a three-dimensional structural diagram of the distribution plate disclosed in the embodiment of the present application;

[0029] Figure 5 It is a side view of the distribution plate disclosed in the embodiment of the present application when assembled on the housing.

[0030] Description of reference numerals:

[0031] 10. Shell; 11. Installation cavity; 12. Through hole; 13. Channel; 14. Positioning groove; 15. Connection hole; 20. Distribution plate; 21. Oil suction channel; 22. Oil discharge channel; 23. Oil suction groove; 24. Oil discharge groove; 30. Rotating cylinder assembly; 31. Transmission shaft; 311. Limiting step; 32. Cylinder; 321. Plunger cavity; 322. Avoidance space; 323. Installation sleeve; 33. Return plate; 34. Plunger; 3 5. Ball head sleeve; 36. Adjustment gasket; 37. First limit piece; 38. Second limit piece; 39. Elastic element; 310. Slipper; 40. Variable assembly; 41. Feedback plunger; 42. Elastic variable mechanism; 421. Sleeve; 422. Elastic piece; 43. Swash plate; 50. Sealing assembly; 51. Sealing cover; 52. Sealing column; 53. Fastener; 60. Ear shaft; 70. Screw; 80. Spring washer; 90. Bearing. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the drawings are all in very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0033] It should be noted that, in order to clearly explain the content of the present invention, the present invention specifically cites multiple embodiments to further illustrate different implementations of the present invention, wherein the multiple embodiments are enumerated rather than exhaustive. In addition, for the sake of brevity of explanation, the contents mentioned in the previous embodiments are often omitted in the subsequent embodiments. Therefore, the contents not mentioned in the subsequent embodiments can refer to the previous embodiments accordingly.

[0034] See also Figures 1 to 3 As shown, according to an embodiment of the present application, a hydraulic variable piston pump is provided, which includes a housing 10 , a valve plate 20 , a rotating cylinder assembly 30 , and a variable assembly 40 .

[0035] The housing 10 is surrounded by a mounting cavity 11, through which the rotating cylinder assembly 30 and the variable assembly 40 can be installed. The fixed cover of the distribution plate 20 is arranged at the first end of the housing 10, and the distribution plate 20 is provided with an oil suction channel 21 and an oil discharge channel 22, which are convenient for conveying hydraulic oil; the rotating cylinder assembly 30 includes a transmission shaft 31, a cylinder body 32 and a plunger 34. When installed, the transmission shaft 31 can be rotatably arranged in the mounting cavity 11 and extend out of the housing 10. The cylinder body 32 is sleeved on the transmission shaft 31 and rotates synchronously with the transmission shaft 31 so that the plunger cavity 321 is selectively connected with the oil suction channel 21 and the oil discharge channel 22. The cylinder body 32 is provided with a plunger cavity 321, and the plunger 34 is arranged in the plunger cavity 321 and can reciprocate along the axial direction of the transmission shaft 31. Movement; the variable component 40 includes a feedback plunger 41, an elastic variable mechanism 42 and a swash plate 43. When installed, the feedback plunger 41 and the elastic variable mechanism 42 are located on the same side of the swash plate 43 (specifically, they are arranged on the side of the swash plate 43 away from the distribution plate 20). The swash plate 43 is arranged in the installation cavity 11 and is driven by the feedback plunger 41 and the elastic variable mechanism 42 to reciprocate along the axial direction of the transmission shaft 31 (that is, the swash plate 43 swings left and right along the axial direction of the transmission shaft 31). When the swash plate 43 swings back and forth, it can actually exert a force on the plunger 34 along the axial direction of the transmission shaft 31, thereby driving the plunger 34 to move axially.

[0036] In actual use, the end of the transmission shaft 31 extending out of the housing 10 is connected to a driving device such as a motor. At this time, the transmission shaft 31 is driven to rotate by the motor, so that the cylinder 32 and the plunger 34 can be driven to rotate. During the rotation process, the plunger cavity 321 on the cylinder 32 can selectively communicate with the oil suction channel 21 and the oil discharge channel 22 on the valve plate 20. At the same time, the hydraulic variable plunger pump is variable-adjusted. Figure 1As shown, the housing 10 is provided with a channel 13, which is connected to the feedback plunger 41. The hydraulic variable plunger pump is also provided with a variable control valve, which is remotely connected to the housing 10 through the channel 13. When working, the pressure and flow of the hydraulic oil flowing out of the oil outlet of the hydraulic variable plunger pump will be fed back to the variable control valve, such as a constant pressure control valve, a constant power control valve, etc., and then the variable control valve is used to output the control oil as needed, and the oil enters the inner cavity of the feedback plunger 41. If the control oil entering the inner cavity of the feedback plunger 41 is high-pressure oil, the feedback plunger 41 is pushed to move to one side of the swash plate 43, and then the swash plate 43 is pushed to swing in the direction of reducing the inclination angle until the swash plate 43 is balanced by force, and the oil of the hydraulic variable plunger pump is reduced at this time. During operation, the feedback plunger 41 can cooperate with the elastic variable mechanism 42 to exert force on the swash plate 43 in the installation cavity 11, thereby driving the swash plate 43 to swing back and forth along the axial direction of the transmission shaft 31. During the swinging of the swash plate 43, the plunger 34 can be driven to reciprocate along the axial direction of the transmission shaft 31 to suck the hydraulic oil from the suction channel 21 into the plunger cavity 321 or discharge the hydraulic oil from the discharge channel 22. If the control oil entering the inner cavity of the feedback plunger 41 is low-pressure oil, the swash plate 43 will swing in the direction of increasing the inclination angle under the action of the elastic variable mechanism 42 until the swash plate 43 is balanced by force, and the hydraulic variable plunger pump is at this time. In other words, the swing angle of the swash plate 43 determines the axial stroke of the plunger 34, that is, by controlling the swing angle of the swash plate 43, the stroke of the plunger 34 can be controlled, and the displacement of the variable pump can be controlled to achieve variable control. Specifically, when the plunger 34 moves toward the side of the swash plate 43, it is just located on the side of the distribution plate 20 where the oil suction channel 21 is opened, and the plunger 34 enters the oil suction stroke. The plunger cavity 321 on the cylinder body 32 is connected to the oil suction channel 21 on the distribution plate 20, and the hydraulic oil enters the plunger cavity 321 through this oil suction channel 21. When the plunger 34 moves toward the side of the distribution plate 20, the plunger 34 enters the oil discharge stroke. The plunger cavity 321 on the cylinder body 32 is connected to the oil discharge channel 22 on the distribution plate 20, and the hydraulic oil is pressed out from the plunger cavity 321 through the oil discharge channel 22 on the distribution plate 20. As the transmission shaft 31 continues to rotate, the plunger 34 performs reciprocating linear motion in the plunger cavity 321 of the cylinder body 32, and the hydraulic variable plunger pump continuously discharges high-pressure oil.

[0037] In this embodiment, since the core components of the variable assembly 40, namely the elastic variable mechanism 42 and the feedback piston 41, are arranged on the same side of the swash plate 43, the structure is more compact, the structural space of the hydraulic variable piston pump can be reasonably utilized, the volume and weight of the hydraulic variable piston pump can be reduced, and it is easier to realize the miniaturization and lightweight design of the hydraulic variable piston pump.

[0038] Furthermore, in this embodiment, the cylinder body 32 is provided with a plurality of plunger cavities 321 in the circumferential direction, and there are a plurality of plungers 34, which are arranged in correspondence with each other in the plurality of plunger cavities 321; and the rotary cylinder assembly 30 further includes a return plate 33, which is arranged in the mounting cavity 11 and located at the end of the cylinder body 32 away from the valve plate 20, and the end of the plunger 34 close to the return plate 33 is movably connected to the return plate 33, and the swash plate 43 is installed on the housing 10 through the ear shaft 60, and reciprocates along the axial direction of the transmission shaft 31. In actual operation, the swing of the swash plate 43 can drive the return plate 33 to move, that is, drive the plurality of plungers 34 to move, and the structure is simple and reliable, and easier to control.

[0039] In some embodiments of the present application, the housing 10 may be a circular housing, a prismatic housing, or other special-shaped housings. Figures 1 to 3 The case where the housing 10 is set as a circular housing is shown in the figure. In this embodiment, at least one connecting hole 15 is set on the housing 10, and the connecting hole 15 is connected to the installation cavity 11. When the hydraulic variable piston pump in the present application is used in other systems, such as an electro-hydraulic servo system, the connecting hole 15 is set on the housing 10 to facilitate the integration of the hydraulic variable piston pump and the electro-hydraulic servo system. At this time, the variable pump can be "inserted" into other structures on the electro-hydraulic servo system. The oil suction channel 21 and the oil discharge channel 22 on the distribution plate 20 and the connecting hole 15 can be used as a guide hole, which can save the connection structure such as the oil suction, oil discharge and oil return pipe between the hydraulic variable piston pump and the electro-hydraulic servo system, reduce the number of external seals of the hydraulic variable piston pump, reduce external leakage, and facilitate the miniaturization and lightweight design of the hydraulic variable piston pump. Compared with the "external" flange installation method in the prior art, in the present application, by setting a connecting hole 15 on the outer shell 10, the embedded installation of the hydraulic variable piston pump and other structures on the electro-hydraulic servo system can be realized, which is convenient for connecting with external constant pressure, constant power and other variable control valves to realize variables, and is more convenient for realizing the miniaturization design of the electro-hydraulic servo system.

[0040] Combination Figures 2 to 5 As shown, the distribution plate 20 in this embodiment is provided with an oil suction groove 23 and an oil discharge groove 24 on one side close to the installation cavity 11. In actual operation, the oil suction channel 21 is connected with the plunger cavity 321 through the oil suction groove 23, and the oil discharge channel 22 is connected with the plunger cavity 321 through the oil discharge groove 24. When the cylinder body 32 rotates, the oil suction groove 23 can be connected with multiple plunger cavities 321 at the same time, and similarly, the oil discharge groove 24 can also be connected with multiple plunger cavities 321 at the same time, which can simplify the structure of the hydraulic variable plunger pump to a certain extent.

[0041] During actual installation, the valve plate 20 and the housing 10 are sealed in surface contact and fixedly connected by screws 70 and spring washers 80. The mating surface of the valve plate 20 and the housing 10 (the contact plane between the valve plate 20 and the housing 10) has the function of isolating low pressure and high pressure. During processing, the flatness and roughness must be ensured, and the tightening torque of the screws 70 must be ensured, so that an effective sealing effect can be achieved to prevent high and low pressures from being connected.

[0042] Furthermore, the rotary cylinder assembly 30 in this embodiment further includes a ball sleeve 35, and a mounting sleeve 323 is provided on the cylinder 32, the mounting sleeve 323 is coaxially arranged with the transmission shaft 31, the ball sleeve 35 is fixedly sleeved on the mounting sleeve 323, and the return plate 33 is rotatably connected to the cylinder 32 through the ball sleeve 35. In actual operation, the return plate 33 rotates and swings along the axis direction of the transmission shaft 31 under the drive of the cylinder 32 and the swash plate 43, and then can drive the plunger 34 to reciprocate along the axis direction of the transmission shaft 31 to suck the hydraulic oil into the plunger cavity 321 or discharge the hydraulic oil from the plunger cavity 321, and the structure is simple, stable and reliable.

[0043] During actual connection, the end of the plunger 34 close to the return plate 33 is a ball head, which is rotatably connected to the return plate 33 through the slipper 310. In order to adjust the gap between the slipper 310 and the swash plate 43, the rotating cylinder assembly 30 in this embodiment also includes a plurality of adjusting gaskets 36 of different thicknesses, which can be selectively sleeved on the mounting sleeve 323. The adjusting gasket 36 is arranged at the end of the ball head sleeve 35 away from the swash plate 43. By selecting adjusting gaskets 36 of different thicknesses to be installed between the mounting sleeves 323, the gap between the slipper 310 and the swash plate 43 can be adjusted, so that the gap between the slipper 310 and the swash plate 43 is within an appropriate range, thereby ensuring the lubricating oil film thickness of the slipper pair, reducing wear and increasing service life.

[0044] Furthermore, in the present embodiment, a side of the cylinder body 32 close to the distribution plate 20 is provided with an escape space 322, and a limiting step 311 is provided on the transmission shaft 31, the transmission shaft 31 is penetrated through the escape space 322, and the limiting step 311 stops inside the escape space 322; and the rotating cylinder body assembly 30 also includes a first limiting member 37, a second limiting member 38 and an elastic element 39, wherein the first limiting member 37 is sleeved on the transmission shaft 31 and is located on the side of the limiting step 311 close to the distribution plate 20, the second limiting member 38 is fixedly arranged on the cylinder body 32 and is located on the inner wall of the escape space 322, and the elastic element 39 is abutted and arranged between the first limiting member 37 and the second limiting member 38, through the action of the first limiting member 37, the second limiting member 38 and the elastic element 39, after assembly, the cylinder body 32 and the distribution plate 20 are in tighter contact, which can play a pre-sealing role when the variable pump is started, thereby ensuring the normal start-up of the variable pump. In addition, the cylinder body 32 and the valve plate 20 are tightly connected together, which can play a certain sealing role and can prevent the hydraulic pressure from flowing out of the gap between the valve plate 20 and the cylinder body 32 to a certain extent. At the same time, in this embodiment, the gap between the sliding shoe 310 and the swash plate 43 is adjusted by setting the adjusting gasket 36. In the actual assembly process of the cylinder body 32, the elastic element 39 does not bear the return function, but only provides a pre-sealing force for the valve pair of the hydraulic variable piston pump when starting, which greatly reduces the stiffness of the elastic element 39 and reduces the difficulty of assembling the elastic element 39, which is convenient for meeting the high-speed and high-pressure working requirements of the hydraulic variable piston pump and improves the power-to-weight ratio of the hydraulic variable piston pump.

[0045] Optionally, the elastic element 39 in this embodiment may be, for example, a spring, and the first limiting member 37 and the second limiting member 38 may be, for example, structures such as limiting plates or limiting blocks.

[0046] Furthermore, the hydraulic variable piston pump in this embodiment further includes an ear shaft 60 , the axial direction of the ear shaft 60 is perpendicular to the axial direction of the transmission shaft 31 , and the swash plate 43 is connected to the housing 10 via the ear shaft 60 to swing along the axial direction of the transmission shaft 31 .

[0047] Combination Figures 1 to 5As shown, the hydraulic variable piston pump in this embodiment further includes a variable control valve (not shown in the figure), which is arranged outside the housing 10 and connected to the feedback piston 41 through a channel 13 arranged on the housing 10 to enable the feedback piston 41 to reciprocate in a direction parallel to the transmission shaft 31. When the hydraulic variable piston pump is working, the flow rate and pressure of the oil discharged by the hydraulic variable piston pump will be fed back to the external variable control valve, such as a constant pressure control valve, a constant power control valve, etc., and the variable control valve outputs the control oil as needed to enter the inner cavity of the feedback piston 41 through the variable control port of the hydraulic variable piston pump. If the control oil is high-pressure oil, the feedback plunger 41 is pushed to move toward the side of the swash plate 43, pushing the swash plate 43 to swing in the direction of reducing the inclination angle until the force on the swash plate 43 is balanced, and the hydraulic variable plunger pump discharges less oil; similarly, if the control oil pressure decreases, under the action of the elastic variable mechanism 42, the elastic variable mechanism 42 pushes the swash plate 43 toward the side of the swash plate to swing in the direction of increasing the inclination angle until the force on the swash plate 43 is balanced, and the hydraulic variable plunger pump discharges more oil.

[0048] In order to facilitate the installation of the elastic variable mechanism 42, a positioning groove 14 is provided on the inner wall of the installation cavity 11 in this embodiment, and the depth direction of the positioning groove 14 is parallel to the length direction of the transmission shaft 31, and the elastic variable mechanism 42 includes a sleeve 421 and an elastic member 422, wherein the sleeve 421 is buckled in the positioning groove 14, and the two ends of the elastic member 422 respectively abut against the bottom of the positioning groove 14 and the bottom of the sleeve 421, and abuts against the swash plate 43 through the sleeve 421, with a simple structure, stable and reliable. Optionally, the elastic member 422 in this embodiment can be a spring, or an elastic column or other structure, as long as it is other deformation methods under the conception of this application, they are all within the protection scope of this application.

[0049] Furthermore, the transmission shaft 31 in this embodiment extends along the length direction of the housing 10, and the two ends of the transmission shaft 31 are rotatably connected to the distribution plate 20 and the housing 10, respectively. The end of the transmission shaft 31 away from the distribution plate 20 may or may not extend out of the housing 10. Since the transmission shaft 31 extends along the length direction of the housing 10, and its two ends are respectively mounted on the distribution plate 20 and the housing 10, that is to say, the transmission shaft 31 in this embodiment is arranged through the length direction of the hydraulic variable piston pump, and the overall through-shaft form is adopted, the structure is simpler, and the axial dimension of the hydraulic variable piston pump can be reduced to a certain extent, which is convenient for realizing the miniaturization design of the hydraulic variable piston pump and can reduce the installation space of the hydraulic variable piston pump.

[0050] Optionally, the second end of the housing 10 in this embodiment, which is away from the first end (i.e., the distribution plate 20 is provided), is provided with a through hole 12 connected to the installation cavity 11. During actual installation, the transmission shaft 31 extends from the through hole 12 to the outside of the housing 10. The hydraulic variable piston pump in this embodiment also includes a sealing assembly 50, which is provided in the housing 10 to seal the through hole 12. Specifically, the sealing assembly 50 includes a sealing cover 51, a sealing column 52 and a fastener 53, wherein the sealing column 52 is integrated with the sealing cover 51, and the fastener 53 is used to fix the sealing cover 51 to the housing 10. In the present application, the sealing cover 51 and the sealing column 52 are integrated into one body, which can reduce the volume of the shaft tail sealing structure to a certain extent, and is more convenient for realizing the miniaturized design of the hydraulic variable piston pump. Optionally, the fastener 53 in this embodiment can be, for example, a structure such as a fastening screw.

[0051] On the other hand, the present application also discloses an electro-hydraulic servo system, which includes the hydraulic variable piston pump described above. Therefore, the electro-hydraulic servo system includes all the technical effects of the hydraulic variable piston pump described above. Since the technical effects of the hydraulic variable piston pump have been described in detail above, they will not be repeated here.

[0052] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0053] (1) This application is based on the design concept of structural and functional integration. While working under high-speed and high-pressure conditions, the hydraulic variable piston pump has a compact structure, a small number of parts, and a simple connection method. It not only greatly improves the installation and adjustment efficiency of the hydraulic variable piston pump, but also can greatly improve the integration of the hydraulic variable piston pump. Preliminary estimates show that compared with traditional hydraulic variable piston pumps, under the same power, the volume can be reduced by about 40%, the weight can be reduced by about 30%, and the transmission power density can be increased by up to 50%. The hydraulic variable piston pump has a positive significance for promoting the miniaturization, lightweight, integration and high specific power of integrated oil sources.

[0054] (2) The present application separates the variable control valve, which is more conducive to structural layout and function expansion. By combining different variable control structures, various working conditions such as constant pressure, constant flow, and constant power can be achieved.

[0055] (3) The structure of the present application is simple to implement, the parts processing and manufacturing cost is low, the assembly and adjustment process is good, it has good economy, and is more conducive to promotion and application.

[0056] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0057] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0058] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A hydraulic variable piston pump, characterized in that: include: A housing (10), wherein the housing (10) surrounds and forms a mounting cavity (11); A distribution plate (20), wherein the distribution plate (20) is fixedly covered at the first end of the housing (10), and the distribution plate (20) is provided with an oil suction channel (21) and an oil discharge channel (22); A rotating cylinder assembly (30), the rotating cylinder assembly (30) comprising a transmission shaft (31), a cylinder body (32) and a plunger (34); the transmission shaft (31) is rotatably arranged in the mounting cavity (11) and extends out of the housing (10); a plunger cavity (321) is arranged on the cylinder body (32); the cylinder body (32) is sleeved on the transmission shaft (31) and rotates synchronously with the transmission shaft (31) so that the plunger cavity (321) is selectively connected with the oil suction channel (21) and the oil discharge channel (22); the plunger (34) is arranged in the plunger cavity (321) and reciprocates along the axial direction of the transmission shaft (31); as well as A variable displacement assembly (40), the variable displacement assembly (40) comprising a feedback plunger (41), an elastic variable displacement mechanism (42) and a swash plate (43), the feedback plunger (41) and the elastic variable displacement mechanism (42) being located on the same side of the swash plate (43), the swash plate (43) being arranged in the mounting cavity (11) and reciprocatingly swinging along the axial direction of the transmission shaft (31) under the action of the feedback plunger (41) and the elastic variable displacement mechanism (42), so as to apply a force along the axial direction of the transmission shaft (31) to the plunger (34); The rotary cylinder assembly (30) further comprises a return plate (33), the return plate (33) being arranged in the mounting cavity (11) and being located at an end of the cylinder body (32) away from the distributor plate (20), the end of the plunger (34) close to the return plate (33) being movably connected to the return plate (33), the swash plate (43) being mounted on the housing (10) via an ear shaft (60) and being reciprocatingly swivelled along the axial direction of the transmission shaft (31); The rotating cylinder assembly (30) further comprises a ball head sleeve (35), a mounting sleeve (323) is arranged on the cylinder body (32), the mounting sleeve (323) is arranged coaxially with the transmission shaft (31), the ball head sleeve (35) is fixedly sleeved on the mounting sleeve (323), and the return plate (33) is rotatably connected to the cylinder body (32) via the ball head sleeve (35).

2. The hydraulic variable piston pump according to claim 1, characterized in that: The rotating cylinder assembly (30) further comprises a plurality of adjusting washers (36) of different thicknesses. The plurality of adjusting washers (36) are sleeved on the mounting sleeve (323) and are located at an end of the ball head sleeve (35) away from the swash plate (43).

3. The hydraulic variable piston pump according to claim 1, characterized in that: A positioning groove (14) is provided on the inner wall of the installation cavity (11), the depth direction of the positioning groove (14) is parallel to the axial direction of the transmission shaft (31), the elastic variable mechanism (42) comprises a sleeve (421) and an elastic member (422), the sleeve (421) is buckled in the positioning groove (14), and one end of the sleeve (421) abuts against the swash plate (43), and the two ends of the elastic member (422) respectively abut against the bottom of the positioning groove (14) and the bottom of the sleeve (421); The housing (10) is provided with a channel (13), and the channel (13) is in communication with the feedback plunger (41); The hydraulic variable displacement piston pump further comprises a variable control valve, which is remotely connected to the housing (10) via the passage (13).

4. The hydraulic variable piston pump according to claim 1, characterized in that: The transmission shaft (31) extends along the length direction of the housing (10), and two ends of the transmission shaft (31) are rotatably connected to the distribution plate (20) and the housing (10), respectively.

5. The hydraulic variable piston pump according to claim 4, characterized in that: The second end of the housing (10) is provided with a through hole (12) communicating with the mounting cavity (11), and the transmission shaft (31) extends from the through hole (12) to the outside of the housing (10); The hydraulic variable piston pump further comprises a sealing assembly (50), wherein the sealing assembly (50) is arranged on the housing (10) to seal the through hole (12), wherein the sealing assembly (50) comprises a sealing cover (51), a sealing column (52) and a fastener (53), wherein the sealing column (52) and the sealing cover (51) are integrated into one body, and the fastener (53) is used to fix the sealing cover (51) to the housing (10).

6. The hydraulic variable piston pump according to any one of claims 1 to 5, characterized in that: A side of the cylinder body (32) close to the distribution plate (20) is provided with an escape space (322); a limiting step (311) is provided on the transmission shaft (31); the transmission shaft (31) passes through the escape space (322); and the limiting step (311) is stopped inside the escape space (322); The rotating cylinder assembly (30) further comprises a first limiting member (37), a second limiting member (38) and an elastic element (39); the first limiting member (37) is sleeved on the transmission shaft (31) and is located on a side of the limiting step (311) close to the distribution plate (20); the second limiting member (38) is fixedly arranged on the cylinder body (32) and is located on the inner wall of the avoidance space (322); and the elastic element (39) is arranged between the first limiting member (37) and the second limiting member (38) to abut against the first limiting member (37) and the second limiting member (38).

7. The hydraulic variable piston pump according to any one of claims 1 to 5, characterized in that: At least one connecting hole (15) is provided on the housing (10), and the connecting hole (15) is communicated with the installation cavity (11).

8. An electro-hydraulic servo system, characterized in that: The electro-hydraulic servo system comprises a hydraulic variable piston pump as claimed in any one of claims 1 to 7.

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