Valve flow distribution axial plunger pump

Abstract

The invention relates to a plunger pump, in particular to a valve flow distribution axial plunger pump which comprises a pump shell, a cylinder body, plungers, a swash plate, sliding shoes, a pressing mechanism and an input shaft connected with the swash plate. The pump shell is provided with an oil inlet communicated with a cavity where the swash plate is located, and the plunger oil pressing cavities are connected with a pump oil discharge outlet through oil discharge one-way valves respectively. The pressing mechanism comprises a return plate connected with the sliding shoes in a sleeving mode, an elastic pressing plate fixedly connected with the return plate and a pressing ball head arranged in the center of the end face of the cylinder body. Oil suction channels communicated with the plunger oil pressing cavities are formed in the sliding shoes and the plungers; an oil inlet groove communicated with the oil suction channel on the sliding shoe is formed in the oil suction area of the swash plate; the middle of the elastic pressing plate is provided with a pressing ball seat which abuts against the pressing ball head in a matched mode. The number of parts of the pressing mechanism is small, the structure is simple, the pressing ball head applies acting force to the return plate through the elastic pressing plate, large return force is obtained in a limited space, and eccentric wear of the sliding shoe caused by insufficient return force is avoided.

Description

Technical Field

[0001] The present invention relates to a plunger pump, and more particularly to a valve-distributed axial plunger pump. Background Art

[0002] The plunger pump is a commonly used reciprocating positive displacement pump, which is mainly composed of a pump housing, a cylinder, a plunger, a swash plate, a shoe and various valves. The plunger reciprocates in the cylinder, and combined with the function of the one-way valve, the liquid is sucked in and discharged. The plunger pump has a compact structure, less medium leakage, higher volumetric efficiency, and can achieve high speed and high pressure. Therefore, compared with the many defects of the gear pump, the plunger pump has higher reliability under high-pressure conditions.

[0003] Chinese patent document CN 112032009A discloses a valve-distributed axial piston pump, which includes an input shaft, a swash plate, a pressure plate, a middle end housing, a cylinder body, a plunger, a slipper, and a rear end housing. When the input shaft drives the swash plate to rotate, the slipper and the plunger are pushed to reciprocate in the cylinder body, so that the plunger cavity absorbs and presses oil. A sealing element is arranged between the plunger and the plunger cavity to prevent the oil from flowing out of the gap between the plunger and the cylinder body. The clamping mechanism can clamp the slipper and the plunger assembly so that it is not too far away from the swash plate. The front one-way valve is only opened when the slipper and the plunger are in the oil suction area, and the rear one-way valve is only opened when the oil is pressed. In this technical solution, the clamping mechanism includes a front end of a spring sleeve, a center spring and a rear end of a spring sleeve, the front end of the spring sleeve is rotatably connected to the center ball, the center spring is arranged in a cavity surrounded by the front end of the spring sleeve and the rear end of the spring sleeve, the rear end of the spring sleeve is slidably connected to the front end of the spring sleeve, the rear end of the spring sleeve is slidably arranged in the cylinder, and sealing elements are arranged between the front end of the spring sleeve and the rear end of the spring sleeve, and between the rear end of the spring sleeve and the cylinder. This clamping mechanism has many parts and a complex structure. Summary of the invention

[0004] The technical problem to be solved by the present invention is the complicated clamping structure of the existing plunger pump, and a valve distribution axial plunger pump is provided to simplify the clamping structure and improve the reliability and practical life.

[0005] The technical solution for achieving the purpose of the present invention is: a valve-distributed axial piston pump, comprising a pump housing, a cylinder body fixedly mounted in the inner cavity of the pump housing, plungers arranged in each axial plunger cavity of the cylinder body, a swash plate arranged in the inner cavity of the pump housing and located on the axial end side of the cylinder body, a sliding shoe ball-hinged to each plunger end and cooperating with the swash plate, a clamping mechanism for abutting each sliding shoe against the swash plate, and an input shaft rotatably passing through the pump housing along the axial direction of the cylinder body and connected to the swash plate; an oil inlet connected to the chamber where the swash plate is located is provided on the pump housing, and each plunger oil pressure cavity is connected to the pump oil discharge port via an oil discharge check valve.

[0006] The clamping mechanism includes a return plate sleeved with each sliding shoe, an elastic pressure plate fixedly connected to the return plate, and a clamping ball head arranged at the center of the end surface of the cylinder body; each sliding shoe and the plunger are provided with an oil suction channel connected to the plunger oil pressure chamber; the inclined plate is provided with an oil inlet groove connected to the oil suction channel on the sliding shoe in its oil suction area; a clamping ball seat is provided in the middle of the elastic pressure plate and abuts against the clamping ball head.

[0007] In the present invention, the pressing ball head on the cylinder body applies force to the return disk through the elastic pressure plate, so that a larger return force is obtained in a limited space, avoiding eccentric wear of the sliding shoe due to insufficient return force. The elastic pressure plate and the pressing ball head on the cylinder body constitute a return disk pressing mechanism, which has a small number of parts and a simple structure.

[0008] In the valve-distributed axial piston pump of the present invention, the radial outer edges of the return disc and the elastic pressure plate are both circular and fixedly connected at the radial outer edges, and there is a gap between the return disc and the elastic pressure plate in the area surrounded by the radial outer edges for the elastic pressure plate to deform elastically. Furthermore, the radial outer edge of the return disc is provided with a plurality of notches arranged at intervals along the circumferential direction, and the elastic pressure plate is provided with claws on its radial edge corresponding to the notches on the radial edge of the return disc.

[0009] In the valve-distributed axial piston pump of the present invention, the clamping ball seat is annular and recessed in the direction of the return disc; the middle of the return disc is provided with an avoidance hole for avoiding the clamping ball seat on the elastic pressure plate, or the middle of the return disc is provided with an avoidance hole for avoiding the clamping ball seat on the elastic pressure plate and the inclined disc is provided with an avoidance recess for avoiding the clamping ball seat on the elastic pressure plate. In order to ensure that the elastic pressure plate and the clamping ball head have sufficient contact area, the clamping ball seat needs to have a certain size in the axial direction, and the avoidance hole can accommodate the clamping ball seat, reducing its space requirements.

[0010] In the valve distribution axial piston pump of the present invention, the oil inlet groove is in an arc shape.

[0011] In the valve-distributed axial piston pump of the present invention, the input shaft is installed in the pump housing through a bearing and is fixedly connected to the swash plate or connected as an integral structure. The input shaft is installed through a bearing and is fixedly connected to the swash plate or is an integral structure, which can ensure the stability of the swash plate during rotation and the coaxiality with the cylinder body, and reduce eccentric wear during operation.

[0012] In the valve-distributed axial piston pump of the present invention, the pump housing includes a housing and an end cover fixedly connected to the end of the housing, the cylinder body is arranged in the housing and the end face abuts against the end cover; each of the oil discharge one-way valves is arranged in the end cover.

[0013] In the valve-distributed axial piston pump of the present invention, the circumferential side surface of the cylinder body is provided with a spline that matches with the inner wall surface of the shell, or the shell is connected to the end cover through a plurality of positioning pins at its end surface.

[0014] In the valve distribution axial piston pump of the present invention, a central through hole axially penetrating the cylinder body is provided at the center of the cylinder body. The central through hole can reduce the weight of the cylinder body. At the same time, the high-pressure oil discharge passage of the plunger cavity intersects with the fitting surface between the end cover and the cylinder body. The discharge oil passage of the plunger cavity will have oil leaking into the gap between the cylinder body and the end cover. If the oil accumulates there, it will cause the cylinder body to move toward the swash plate. The central through hole can guide the oil in the gap between the cylinder body and the end cover to the inner cavity of the housing. The inner cavity of the housing is the oil inlet cavity, which is a low-pressure oil cavity.

[0015] In the valve distribution axial piston pump of the present invention, the piston cavity is formed by a round through hole axially penetrating the cylinder body. The cylinder body piston cavity adopts a cylindrical through structure, that is, the diameter of the hole opening and the hole bottom are the same, and the size and shape tolerance are easy to ensure.

[0016] Compared with the prior art, in the present invention, the pressing ball head on the cylinder body applies force to the return disc through the elastic pressure plate, so that a larger return force is obtained in a limited space, avoiding eccentric wear of the sliding shoe due to insufficient return force. The return disc, the elastic pressure plate and the pressing ball head on the cylinder body constitute a return disc pressing mechanism, which has a small number of parts and a simple structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the valve distribution axial piston pump of the present invention.

[0018] Figure 2 It is an exploded view of the inclined plate, plunger, clamping mechanism and cylinder body in the valve distribution axial piston pump of the present invention.

[0019] Figure 3 It is a structural schematic diagram of a return disc and an elastic pressure plate in a valve distribution axial piston pump of the present invention.

[0020] Parts names and serial numbers in the figure:

[0021] Pump casing 10 , housing 11 , end cover 12 , oil inlet 13 , pump oil outlet 14 .

[0022] Input shaft 21 , swash plate 22 , bearing 23 , avoidance recess 24 , oil inlet groove 25 .

[0023] Cylinder body 30, plunger cavity 31, plunger 32, sliding shoe 33, oil suction channel 34, sliding shoe oil through hole 341, plunger oil through hole 342, center through hole 35, positioning pin 36, positioning pin hole 37, clamping ball head 38, plunger oil pressure cavity 39.

[0024] The return plate 40 , the first ball seat through hole 41 , the notch 42 , and the avoidance hole 43 .

[0025] Elastic pressing plate 50 , pressing ball seat 51 , second ball seat through hole 52 , and clamping claw 53 .

[0026] Oil discharge one-way valve 60 , valve core 61 , spring chamber 62 , return spring 63 , buffer oil hole 64 . DETAILED DESCRIPTION

[0027] The specific implementation scheme is described below with reference to the accompanying drawings.

[0028] like Figure 1 As shown, the valve distribution axial piston pump includes a pump housing 10, a cylinder body 30 fixedly mounted in the inner cavity of the pump housing 10, a plunger 32 arranged in each axial plunger cavity 31 in the cylinder body, a swash plate 22 arranged in the inner cavity of the pump housing 10 and located on the axial end side of the cylinder body 30, a sliding shoe 33 ball-hinged to the end of each plunger 32 and abutting against the swash plate 22, a clamping mechanism for abutting each sliding shoe 33 against the swash plate 22, and an input shaft 21 rotatably passing through the pump housing 10 along the axial direction of the cylinder body and connected to the swash plate 22; the pump housing 10 is provided with an oil inlet 13 connected to the chamber where the swash plate 22 is located, and each plunger oil pressure cavity 39 is connected to the pump oil discharge port 14 through an oil discharge check valve 60.

[0029] The clamping mechanism includes a return plate 40 sleeved with each sliding shoe 33, an elastic pressure plate 50 fixedly connected to the return plate 40, and a clamping ball head 38 arranged at the center of the end face of the cylinder body 30; each sliding shoe 33 and the plunger 32 is provided with an oil suction channel connected to the plunger oil pressure chamber 39; the swash plate 22 is provided with an oil inlet groove 25 connected to the oil suction channel on the sliding shoe 33 in its oil suction area; a clamping ball seat 51 is provided in the middle of the elastic pressure plate 50 to abut and cooperate with the clamping ball head 38.

[0030] Alternatively, if Figure 1 As shown, the pump housing 10 includes a housing 11 and an end cover 12 fixedly connected to the end of the housing 11, the cylinder body 30 is arranged in a cavity formed by the housing 11 and the end cover 12, and the end surface of the cylinder body 30 abuts against the end cover 12; each oil discharge one-way valve 60 connected to each plunger oil pressure chamber 39 in the cylinder body 30 is arranged in the end cover 12.

[0031] like Figure 2As shown, a plurality of positioning pin holes 37 are provided on the end surface of the cylinder body 30 abutting against the end cover 12, and correspondingly, pin holes corresponding to the positioning pin holes 37 on the cylinder body 30 are provided on the end cover 12, and positioning pins 36 are installed in the coaxially aligned positioning pin holes 37 and the pin holes on the end cover 12, so that the cylinder body 30 is circumferentially positioned relative to the pump housing 10 to prevent the cylinder body 30 from circumferentially rotating relative to the pump housing 10. The cylinder body 30 realizes its radial positioning by cooperating with the inner cavity wall of the housing 11 through its circumferential side surface, and a sealing ring is provided between the circumferential side surface of the cylinder body 30 and the inner cavity wall of the housing 11 to prevent oil leakage in the gap.

[0032] In some embodiments, an external spline may be provided on the circumferential side of the cylinder body 30 and an internal spline may be provided on the inner wall of the shell 11. The cylinder body 30 and the shell 11 are matched by the internal and external splines to achieve circumferential positioning of the cylinder body 30 relative to the shell 11.

[0033] like Figure 2 As shown, the cylinder body 30 is provided with a plurality of through holes around its center, each of which forms a plunger cavity 31, and a plunger 32 is arranged in each plunger cavity 31. The plunger cavity 31 of the cylinder body 30 adopts a cylindrical through structure, that is, the diameter of the hole opening is the same as that of the hole bottom, and the size and shape tolerance are easy to ensure. Figure 1 As shown, the plunger 32 cooperates with the plunger cavity 31 to form a plunger oil pressure cavity 39 at the end of the plunger 32 , and the plunger oil pressure cavity 39 is connected to the pump oil discharge port 14 through an oil discharge channel 65 provided in the end cover 12 .

[0034] like Figure 1 As shown, the input shaft 21 is installed in the pump housing 10 through the bearing 23 and is fixedly connected to the swash plate 22 in the inner cavity of the pump housing 10. A preferred embodiment is that the input shaft 21 and the swash plate 22 are connected as an integral structure and are a rigid body. In some other embodiments, the input shaft 21 can also be detachably fixedly connected to the swash plate 22.

[0035] Each sliding shoe 33 is abutted against the swash plate 22 through a clamping mechanism, and the swash plate 22 is provided with an oil inlet groove 25 in its oil suction area that is connected to the oil suction channel on the sliding shoe 33. Figure 2 As shown, the oil inlet groove 25 is in an arc shape, and the oil inlet groove 25 can be connected with the oil suction channel 34 on the sliding shoe 33 located in the oil suction area of ​​the swash plate 22. When the sliding shoe 33 slides to the oil pressure area of ​​the swash plate 22, the sliding shoe 33 and the swash plate 22 are in surface contact, and the surface contact can close the communication channel between the oil suction channel 34 on the sliding shoe 33 and the inner cavity of the pump housing 10.

[0036] The sliding shoe 33 is connected to the end of the plunger 32 by a ball joint, an axially penetrating plunger oil hole 342 is provided in the plunger 32, and a sliding shoe oil hole 341 is provided on the sliding shoe 33. One end of the plunger oil hole 342 is connected to the sliding shoe oil hole 341 to form an oil suction channel 34. The other end of the plunger oil hole 342 is connected to the plunger oil pressure chamber 39.

[0037] The ball seat on the slipper 33 that cooperates with the ball head at the end of the plunger 32 has a closing structure, so that when the swash plate 22 rotates, the slipper 33 located in the oil pressure area of ​​the swash plate 22 can axially push the plunger 32 to move and squeeze the hydraulic oil in the plunger oil pressure chamber 39, and the slipper 33 in the oil suction area can pull the plunger 32 to move to suck oil.

[0038] In the clamping mechanism, the return disc 40 is fixedly connected to the elastic pressure plate 50. Figure 3 As shown, the return plate 40 and the elastic pressure plate 50 are both disc-shaped, and the return plate 40 is provided with first ball seat through holes 41 corresponding to the number of plungers 32, and the elastic pressure plate 50 is provided with second ball seat through holes 52 corresponding to the number of plungers. The first ball seat through holes 41 and the second ball seat through holes 52 are arranged coaxially in a one-to-one correspondence, and the ball seats on the sliding shoes 33 pass through. The return plate 40 contacts and abuts against the shoe portion of the sliding shoe 33, and abuts the sliding shoe 33 against the swash plate 22.

[0039] A plurality of notches 42 are provided on the circumferential edge of the return disk 40, and the notches 42 are arranged at equal intervals on the circumferential edge of the return disk 40. A claw 53 is provided on the elastic pressure plate 50 corresponding to each notch 42 on the return disk 40, and the claw 53 is embedded in the notch 42 on the return disk 40, so that the elastic pressure plate 50 is fixedly connected to the return disk 40. There is a gap between the return disk 40 and the elastic pressure plate 50 in the area surrounded by the outer edge connection part, and the gap provides space for the elastic pressure plate 50 to deform elastically.

[0040] The pressing ball head 38 in the pressing mechanism is arranged at the middle of the end surface of the cylinder body 30 and is an integral structure with the cylinder body 30. A pressing ball seat 51 is arranged in the middle of the elastic pressing plate 50 to cooperate with and abut against the pressing ball head 38. The pressing ball seat 51 is annular and concave toward the return disc 40.

[0041] like Figure 3 As shown, an avoidance hole 43 is provided in the middle of the return disc 40 for avoiding the clamping ball seat 51 on the elastic pressure plate 50. The avoidance hole 43 enables the clamping ball seat 51 to be located therein, and the distance between the elastic pressure plate 50 and the return disc 40 is reduced while ensuring that the clamping ball seat 51 and the clamping ball head 38 have sufficient contact area.

[0042] Furthermore, an avoidance recess 24 for avoiding the clamping ball seat 51 is provided on the swash plate 22. This structure enables the clamping ball seat 51 to pass through the avoidance hole 43 on the return plate 40 and extend into the avoidance recess 24 on the swash plate 22, thereby further increasing the area of ​​the clamping ball seat 51 within the limited circumferential space.

[0043] like Figure 2 Figure 3 As shown, a central through hole 35 axially penetrating the cylinder body is provided at the center of the cylinder body 60. One end of the central through hole 35 is located on the end surface of the cylinder body 30 abutting against the end cover 12, and the other end of the central through hole 35 is located on the pressing ball head 38 and communicates with the inner cavity of the pump housing 10. The inner cavity of the pump housing 10 is communicated with the oil inlet 13 on the housing 11, and the inner cavity of the pump housing 10 is filled with low-pressure oil, which can enter the oil suction channel 34 of the plunger pressure oil chamber 39 through the oil inlet groove 25 on the swash plate 22.

[0044] The central through hole 35 can reduce the weight of the cylinder body and can also guide the pressure oil in the gap between the end surface of the cylinder body 30 and the end cover 12. Figure 1 As shown, the plunger pressure oil chamber 39 is located in the cylinder body 30, the pump oil discharge port 14 is located on the end cover 12, and the oil discharge channel 65 from the pump oil discharge port 14 to the plunger pressure oil chamber 39 intersects with the side of the end cover 12. The high-pressure oil in the oil discharge channel 65 will leak into the gap between the cylinder body 30 and the end cover 12. If the oil accumulates there, it will cause the cylinder body 30 to move toward the swash plate 22. The central through hole 35 can guide the oil in the gap between the cylinder body 30 and the end cover 12 to the inner cavity of the pump housing. The inner cavity of the pump housing is the oil inlet cavity, which is a low-pressure oil cavity.

[0045] The oil discharge check valve 60 is disposed in the end cover 12. Figure 1 As shown, the oil discharge check valve 60 includes a valve core 61 and a return spring 63. The valve core 61 cooperates with the end cover 12 to form a spring chamber 62, and the return spring 63 is arranged in the spring chamber 62. The chamber on the end cover 12 that accommodates the valve core 61 intersects with the oil discharge passage 65. The valve core 61 moves and compresses the return spring 63 under the action of the pressure oil in the plunger pressure oil chamber 39. The movement of the valve core 61 makes the oil discharge passage 65 conductive, and the oil in the plunger pressure oil chamber 39 is discharged through the oil discharge passage 65. When the plunger 32 moves to absorb oil, the valve core 61 moves toward the plunger pressure oil chamber 39 under the elastic force of the return spring 63, cutting off the oil discharge passage 65, so that the pressure oil at the pump discharge port 14 cannot reversely enter the plunger pressure oil chamber 39.

[0046] A buffer oil hole 64 is provided on the valve core 91. The buffer oil hole 64 connects the spring chamber 62 and the oil discharge channel 65, and the connecting area changes with the position of the valve core 61. When the valve core 61 cuts off the oil discharge channel 65, the effective flow area of ​​the buffer oil hole 64 connecting the spring chamber 62 and the oil discharge channel 65 is the largest. When the valve core 61 compresses the reset spring 63 under the push of the pressure oil, due to the blocking of the buffer oil hole 64 by the wall of the valve core accommodating chamber, the effective flow area of ​​the buffer oil hole 64 connecting the spring chamber 62 and the oil discharge channel 65 gradually decreases and reaches the minimum at the end of the valve core stroke. When the valve core 61 moves to compress the reset spring 63, the oil in the spring chamber 62 needs to flow out through the buffer oil hole 64 and enter the oil discharge channel 65. As the effective flow area of ​​the buffer oil hole 64 decreases, the flow rate of the oil in the spring chamber 62 slows down, thereby playing a buffering role for the valve core 61 when the valve core 61 opens the oil discharge channel 65.

[0047] In the present invention, the pressing ball head on the cylinder body 30 applies a force to the return disc 40 through the elastic pressure plate 50, so that a larger return force is obtained in a limited space, thereby avoiding eccentric wear of the sliding shoe due to insufficient return force. The return disc, the elastic pressure plate and the pressing ball head on the cylinder body constitute a return disc pressing mechanism, which has a small number of parts and a simple structure.

Claims

1. A valve-distributed axial piston pump, comprising a pump housing, a cylinder body fixedly mounted in the inner cavity of the pump housing, a piston arranged in each axial piston cavity in the cylinder body, a swash plate arranged in the inner cavity of the pump housing and located at the axial end side of the cylinder body, a sliding shoe ball-hinged to each end of each piston and cooperating with the swash plate, a clamping mechanism for abutting each sliding shoe against the swash plate, and an input shaft rotatably passing through the pump housing along the axial direction of the cylinder body and connected to the swash plate; the pump housing is provided with an oil inlet connected to the chamber where the swash plate is located, and each plunger oil pressure cavity is connected to the pump oil discharge port via an oil discharge check valve; It is characterized in that The clamping mechanism includes a return plate sleeved with each sliding shoe, an elastic pressure plate fixedly connected to the return plate, and a clamping ball head arranged at the center of the end surface of the cylinder body; each sliding shoe and the plunger are provided with an oil suction channel connected to the plunger oil pressure chamber; the inclined plate is provided with an oil inlet groove connected to the oil suction channel on the sliding shoe in its oil suction area; a clamping ball seat is provided in the middle of the elastic pressure plate and abuts against the clamping ball head.

2. The valve-distributed axial piston pump according to claim 1, characterized in that: The radial outer edges of the return disc and the elastic pressure plate are both circular and fixedly connected at the radial outer edges. A gap exists between the return disc and the elastic pressure plate in the area surrounded by the radial outer edges for the elastic pressure plate to deform elastically.

3. The valve-distributed axial piston pump according to claim 2, characterized in that: The radial outer edge of the return disc is provided with a plurality of notches spaced apart in the circumferential direction, and the elastic pressure plate is provided with claws on its radial edge correspondingly embedded in the notches at the radial edge of the return disc.

4. The valve-distributed axial piston pump according to claim 2 or 3, characterized in that: The clamping ball seat is in a circular ring structure and is recessed in the direction of the return disk; an avoidance hole for avoiding the clamping ball seat on the elastic pressure plate is provided in the middle of the return disk, or an avoidance hole for avoiding the clamping ball seat on the elastic pressure plate is provided in the middle of the return disk and an avoidance recess for avoiding the clamping ball seat on the elastic pressure plate is provided on the inclined disk.

5. The valve-distributed axial piston pump according to claim 1, characterized in that: The oil inlet groove is in an arc shape.

6. The valve-controlled axial piston pump according to claim 1, characterized in that: The input shaft is installed in the pump housing through a bearing and is fixedly connected to the swash plate or connected in an integral structure.

7. The valve-controlled axial piston pump according to claim 1, characterized in that: The pump housing comprises a housing and an end cover fixedly connected to the end of the housing. The cylinder body is arranged in the housing and the end face abuts against the end cover. Each of the oil discharge one-way valves is arranged in the end cover.

8. The valve-controlled axial piston pump according to claim 7, characterized in that: The circumferential side surface of the cylinder body is provided with a spline that matches with the inner wall surface of the shell, or the shell is connected to the end cover through a plurality of positioning pins at its end surface.

9. The valve-controlled axial piston pump according to claim 7 or 8, characterized in that: The center of the cylinder body is provided with a central through hole which axially penetrates the cylinder body.

10. The valve-controlled axial piston pump according to claim 1, characterized in that: The plunger cavity is formed by a circular through hole that axially penetrates the cylinder body.

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