Inverted quantitative plunger pump

Abstract

The utility model provides an inverted quantitative plunger pump, and belongs to the technical field of liquid pumps. The oil inlet and the oil outlet are directly formed in the barrel bottom of the shell, the swash plate abuts against the rear cover, the oil distribution disc abuts against the barrel bottom of the shell and is communicated with the oil inlet and the oil outlet, and a cylinder body, a plunger and other structures of the pump core assembly are arranged between the oil distribution disc and the swash plate. Inverted installation of the swash plate and the pump core in the shell is achieved, so that the oil inlet and the oil outlet can be formed by directly utilizing the thick barrel bottom of the shell, the oil inlet and the oil outlet do not need to be formed by additionally increasing the thickness of the rear cover, the thickness of the rear cover is reduced, and therefore space occupation in the length direction is avoided, and the oil pump is convenient to use. In addition, the contact face of the oil distribution disc and the cylinder body is arranged to be the spherical face, spherical face flow distribution is achieved, and the stability of the plunger pump under the high-pressure working condition is effectively improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to liquid pump technical field, concretely relates to a kind of inverted quantitative plunger pump. BACKGROUND

[0002] As a kind of liquid pump, plunger pump relies on the reciprocating motion of plunger in cylinder, changes the volume of sealed working cavity in cylinder, realizes oil suction and oil pressure by volume change. In addition, plunger pump is divided into quantitative and variable two kinds, the main difference between quantitative and variable plunger pump is whether the angle of swash plate is adjustable, the plunger pump with adjustable angle of swash plate is variable plunger pump, which realizes the adjustment of plunger stroke in cylinder by changing the angle of swash plate, so that the total volume of working cavity changes, while the plunger pump with unadjustable angle of swash plate is quantitative plunger pump, the stroke of plunger in cylinder is fixed, so that the total volume of working cavity remains unchanged. Although the flow of variable plunger pump is adjustable, its internal structure is complex and more prone to damage, so for some hydraulic systems that require stability, quantitative plunger pump is usually used as power source.

[0003] At present, the existing quantitative plunger pump on the market is usually a plunger pump disclosed in patent CN116221055A, the pump body includes a shell, a transmission shaft, an oil port screw cover, a cylinder, a quantitative swash plate, a return disc, a plunger shoe pair, a needle bearing, a return ball, a spring and a spring positioning ring. At this time, the shell is provided with the cylinder inside, the transmission shaft is provided inside the cylinder, the oil port screw cover is provided at the left end of the shell, the quantitative swash plate is provided at the right end of the transmission shaft, the return disc is provided at the center of the transmission shaft, the plunger shoe pair is provided at the left side of the return disc, and the return ball connected with the quantitative swash plate is provided at the right side of the plunger shoe pair. As can be seen, the shell and the flow distribution pump cover are of split structure, at this time, the oil is introduced and discharged through the flow distribution pump cover. In addition, there is also a structure on the market that the flow distribution pump cover is split, that is, the flow distribution pump cover includes a rear cover and a flow distribution disc, that is, the rear cover needs to be provided with a structure for abutting against the flow distribution disc, and the flow distribution disc is abutted against the cylinder, which can also meet the use requirement. However, this structure needs to set flow channel on the rear cover to cooperate with the flow distribution disc or the cylinder, which results in that the thickness of the rear cover is relatively thick, thereby increasing the overall volume of the plunger pump and increasing the space occupation in the length direction of the plunger pump, which leads to low power density ratio of the plunger pump. SUMMARY

[0004] In view of the above problems existing in the prior art, the present application aims to provide an inverted quantitative plunger pump, which is characterized in that an oil inlet and an oil outlet are formed on the original end face of the shell, the swash plate and the pump core are installed in the shell in an inverted manner, the oil distribution disc is matched with the cylinder in a spherical surface, the stability under high pressure is ensured, the overall thickness of the rear cover is reduced, the space occupation in the length direction is reduced, and the power density ratio of the plunger pump is increased.

[0005] The specific technical solution is as follows:

[0006] An inverted fixed displacement plunger pump includes a housing, a rear cover, a pump core, a swashplate, and a distribution plate. The housing is arranged in a barrel shape, and the rear cover is installed at the opening of the housing. The pump core and the distribution plate are both installed inside the barrel cavity of the housing. The pump core includes a drive shaft, a cylinder block, plungers, and slippers. A through-hole is formed in the bottom of the housing. One end of the drive shaft is rotatably mounted in the through-hole, and the other end extends into the barrel cavity of the housing. A pump core with several plungers is sleeved on the drive shaft. The cylinder body of the piston chamber has a piston slidably installed in each piston chamber. The swash plate is installed on the rear cover and abuts against each piston through a slipper. The bottom of the casing has an oil inlet and an oil outlet that communicate with the inner cavity of the casing. The oil distribution plate is located at the end of the inner cavity of the casing near the bottom of the casing. The oil distribution plate has an oil inlet window and an oil outlet window that communicate with the oil inlet and the oil outlet respectively. The side of the cylinder body away from the swash plate abuts against the oil distribution plate, and the surface of the oil distribution plate abutting against the cylinder body is spherically arranged.

[0007] In the aforementioned inverted fixed displacement plunger pump, the oil inlet and oil outlet are symmetrically arranged on both sides of the bottom of the casing.

[0008] In the aforementioned inverted quantitative piston pump, the inner and outer sides of the bottom of the casing, located at the central hole, are respectively provided with a support hole and a sealing hole, both coaxially arranged with the central hole. An oil seal is provided in the sealing hole, and a support bearing is provided in the support hole. Both the oil seal and the support bearing are sleeved on the outside of the drive shaft.

[0009] In the aforementioned inverted quantitative plunger pump, a groove is provided at the center of the rear cover on the side closest to the housing. One end of the drive shaft extending into the inner cavity of the housing is inserted into the groove. At the same time, an auxiliary bearing is provided in the groove and sleeved on the end of the drive shaft that extends into the groove.

[0010] In the aforementioned inverted quantitative plunger pump, a plurality of limiting holes are provided on the rear cover and on the side near the housing. The side of the swashplate away from the slipper abuts against the side surface of the rear cover with the limiting holes. Furthermore, a plurality of mating holes corresponding one-to-one with the limiting holes are provided on the side of the swashplate opposite to the rear cover, and a limiting pin is provided between the mating hole and the corresponding limiting hole.

[0011] In the aforementioned inverted metering plunger pump, a sealing gasket is provided between the rear cover and the opening of the housing.

[0012] In the aforementioned inverted fixed displacement piston pump, the center of the distribution plate is provided with a clearance hole for the drive shaft to pass through, and the clearance hole is a stepped hole. The large cross-section hole of the stepped hole is located on the side of the distribution plate away from the cylinder block, and the stepped surface of the stepped hole presses against the outer ring of the support bearing.

[0013] In the aforementioned inverted quantitative piston pump, a limiting edge is provided on the outer wall of the drive shaft at one end extending into the inner cavity of the housing. One side of the limiting edge abuts against the inner ring of the support bearing, and an adjusting shim is provided between the limiting edge and the support bearing.

[0014] In the aforementioned inverted quantitative piston pump, the inner side of the bottom of the casing has several positioning grooves arranged in a ring array around the axis of the central hole. The side of the oil distribution plate facing away from the cylinder body has several positioning protrusions that correspond one-to-one with the positioning grooves. Furthermore, each positioning groove has a guide slope at its opening, and the edge of the positioning protrusion has a guide ramp that cooperates with the guide slope.

[0015] In the aforementioned inverted fixed displacement piston pump, a plurality of oil guide grooves are provided on the surface of the oil distribution plate that contacts the cylinder body, and each piston cavity of the cylinder body is connected to each oil guide groove when the cylinder body rotates.

[0016] The positive effects of the above technical solution are:

[0017] The aforementioned inverted fixed displacement plunger pump, by directly opening the oil inlet and outlet in the bottom of the casing, and placing the rear cover at the opening of the casing with the swashplate abutting against the rear cover, and the distribution plate being located on one side of the bottom of the casing and communicating with the oil inlet and outlet, achieves inverted installation of the swashplate and pump core within the casing by placing the swashplate and the pump core inverted within the casing by placing the swashplate and the pump core inverted within the casing by placing the swashplate inverted against the pump core ... Attached Figure Description

[0018] Figure 1 This is a structural diagram of an embodiment of the inverted quantitative plunger pump of the present invention;

[0019] Figure 2 for Figure 1 Enlarged view of section A.

[0020] In the attached diagram: 1. Housing; 11. Center hole; 12. Oil inlet; 13. Oil outlet; 14. Support hole; 15. Sealing hole; 16. Oil seal; 17. Support bearing; 2. Rear cover; 21. Groove; 22. Limiting hole; 23. Auxiliary bearing; 3. Swashplate; 31. Mating hole; 32. Limiting pin; 4. Oil distribution plate; 41. Clearance hole; 5. Drive shaft; 51. Limiting edge; 52. Adjusting shim; 6. Cylinder block; 7. Plunger; 8. Slipper; 9. Sealing gasket. Detailed Implementation

[0021] To make the technical means, creative features, objectives, and effects of this utility model easier to understand, the following embodiments are provided in conjunction with the appendix. Figure 1 and attached Figure 2 The technical solution provided by this utility model is described in detail, but the following content is not intended to limit this utility model.

[0022] Figure 1 This is a structural diagram of an embodiment of the inverted quantitative plunger pump of the present invention; Figure 2 for Figure 1 An enlarged view of section A. (See image below.) Figure 1 As shown, the inverted quantitative plunger pump provided in this embodiment includes: a housing 1, a rear cover 2, a pump core, a swashplate 3, and a distribution plate 4. The pump core also includes a drive shaft 5, a cylinder 6, a plunger 7, and a slipper 8. The housing 1 is arranged in a barrel shape, and the rear cover 2 is installed at the opening of the housing 1. Preferably, the rear cover 2 is connected to the housing 1 by screws, which allows the rear cover 2 to be disassembled and assembled on the housing 1, making it convenient to install the pump core, swashplate 3, and distribution plate 4 into the inner cavity of the housing 1.

[0023] Specifically, the bottom of the housing 1 has a through-hole 11. During assembly, one end of the drive shaft 5 is rotatably installed in the through-hole 11, and the other end of the drive shaft 5 extends into the inner cavity of the housing 1, providing conditions for subsequently driving the cylinder 6 and other structural components to rotate. At this time, a cylinder 6 with several plunger cavities is sleeved on the drive shaft 5, and a plunger 7 is slidably installed in each plunger cavity. The volume of the plunger cavity is changed by the sliding of the plunger 7 in the corresponding plunger cavity, thereby realizing oil suction and oil discharge. In addition, a swashplate 3 is installed on the rear cover 2 and abuts against each plunger 7 through a slipper 8. The swashplate 3 pushes the plunger 7 to slide in the corresponding plunger cavity. In addition, an oil inlet 12 and an oil outlet 13 communicating with the inner cavity of the barrel are provided in the bottom of the housing 1, and an oil distribution plate 4 is set at the end of the inner cavity of the housing 1 near the bottom of the barrel. The oil distribution plate 4 has an oil inlet window and an oil outlet window communicating with the oil inlet 12 and the oil outlet 13 respectively. At the same time, the side of the cylinder block 6 away from the swashplate 3 abuts against the oil distribution plate 4. Compared with the existing plunger pump structure, the swashplate 3, the oil distribution plate 4 and the pump core are installed in reverse in the housing 1. Furthermore, since the bottom of the housing 1 itself serves as the support structure for the drive shaft 5, Furthermore, the installation of structures such as oil seal 16 and bearings results in a relatively thick bottom of the housing 1, similar to traditional plunger pumps. This embodiment fully utilizes the thickness of the bottom of the housing 1 to arrange the oil inlet 12 and oil outlet 13, effectively avoiding the problem of existing plunger pumps requiring increased thickness of the rear cover 2 to arrange the oil inlet 12 and oil outlet 13, thus reducing the space occupied in the length direction and improving the power density ratio of the plunger pump. In addition, the spherical arrangement of the surface where the distribution plate 4 abuts against the cylinder block 6 achieves spherical flow distribution between the distribution plate 4 and the cylinder block 6, improving the stability of the plunger pump under high-pressure conditions and resulting in better performance.

[0024] More specifically, the oil inlet 12 and the oil outlet 13 are symmetrically arranged on both sides of the bottom of the shell 1, which realizes the separation and uniform arrangement of the oil inlet 12 and the oil outlet 13 on the bottom of the shell 1, maintains the structural stability, and also provides a large enough margin for the arrangement, processing and subsequent pipeline connection of the oil inlet 12 and the oil outlet 13.

[0025] More specifically, a support hole 14 is coaxially provided on the inner side of the bottom of the housing 1 and outside the central hole 11. Simultaneously, a sealing hole 15 is coaxially provided on the outer side of the bottom of the housing 1 and outside the central hole 11. Both the support hole 14 and the sealing hole 15 communicate with the central hole 11. During assembly, an oil seal 16 is installed in the sealing hole 15, and a support bearing 17 is installed in the support hole 14. Both the oil seal 16 and the support bearing 17 are fitted onto the outside of the drive shaft 5. Thus, the sealing hole 15 and the support hole 14 provide installation space for the oil seal 16 and the support bearing 17 between the housing 1 and the drive shaft 5, respectively. This prevents oil leakage and stably supports the drive shaft 5 on the bottom of the housing 1, ensuring stable rotation of the drive shaft 5.

[0026] More specifically, a groove 21 is provided at the center of the rear cover 2, located near the housing 1. This groove 21 is positioned using the thickness of the rear cover 2 itself, eliminating the need to increase its thickness and preventing an increase in the total length of the plunger pump. Furthermore, an auxiliary bearing 23 is provided within the groove 21. One end of the drive shaft 5 extending into the inner cavity of the housing 1 is inserted into the groove 21 and fitted with the auxiliary bearing 23. This allows the end of the drive shaft 5 to be supported by the auxiliary bearing 23, ensuring that the end of the drive shaft 5 located within the inner cavity is simultaneously supported by the support bearing 17 on the housing 1 and the auxiliary bearing 23 on the rear cover 2. This improves the stability and load-bearing capacity of the drive shaft 5.

[0027] More specifically, several limiting holes 22 are provided on the rear cover 2, located on the side near the housing 1. The limiting holes 22 are blind holes, and the original thickness of the rear cover 2 can also be used to set the limiting holes 22. At this time, the side of the swashplate 3 away from the slipper 8 is placed against the side of the rear cover 2 with the limiting holes 22. Furthermore, several mating holes 31 corresponding to the limiting holes 22 are provided on the side of the swashplate 3 opposite to the rear cover 2. During assembly, the two ends of a limiting pin 32 are inserted into the mating holes 31 and the corresponding limiting holes 22, respectively. That is, the swashplate 3 is stably installed on the rear cover 2 through the mutual cooperation of the limiting holes 22, the mating holes 31, and the limiting pin 32, and the circumferential of the swashplate 3 is limited to prevent the swashplate 3 from rotating, so that it can be more stable when working with the plunger 7, ensuring that the plunger pump can operate normally.

[0028] More specifically, a sealing gasket 9 is also provided between the rear cover 2 and the opening of the housing 1. The sealing gasket 9 achieves a seal at the connection between the rear cover 2 and the housing 1, preventing oil leakage and improving the safety of the plunger pump.

[0029] More specifically, a clearance hole 41 is provided at the center of the oil distribution plate 4 to accommodate the transmission shaft 5. That is, when the transmission shaft 5 passes through the central hole 11 and extends into the inner cavity of the housing 1, the transmission shaft 5 simultaneously passes through the clearance hole 41 of the oil distribution plate 4, ensuring that the transmission shaft 5 can rotate smoothly. In addition, the clearance hole 41 on the oil distribution plate 4 is a stepped hole, and the large cross-section hole of the stepped hole is located on the side of the oil distribution plate 4 away from the cylinder block 6. Furthermore, when the oil distribution plate 4 is installed on the bottom of the housing 1, the stepped surface of the clearance hole 41 on the oil distribution plate 4 presses against the outer ring of the support bearing 17. This not only restricts the support bearing 17 installed in the support hole 14 of the housing 1 through the stepped surface of the clearance hole 41, maintaining the stability of the support bearing 17 after installation, but also allows the support bearing 17 to be partially hidden in the oil distribution plate 4, making the support bearing 17 and the oil distribution plate 4 more compact, avoiding wasted space, further avoiding space occupation in the length direction, and further increasing the power density ratio of the plunger pump.

[0030] More specifically, a limiting edge 51 is provided on the outer wall of the end of the drive shaft 5 that extends into the inner cavity of the housing 1. Preferably, the limiting edge 51 and the drive shaft 5 are integrally formed, resulting in better integrity and higher structural strength. Furthermore, one side of the limiting edge 51 abuts against the inner ring of the support bearing 17. Through the cooperation between the limiting edge 51 and the support bearing 17, the drive shaft 5 is axially limited, preventing it from reversing and dislodging from the central hole 11. Additionally, the limiting edge 51 presses against the support bearing 17, further improving the stability of the limiting bearing after installation. Moreover, an adjusting shim 52 is provided between the limiting edge 51 and the support bearing 17. The distance between the limiting edge 51 and the support bearing 17 can be adjusted using the shim 52 to meet the needs of applications where the limiting edge 51 cannot fully abut against the support bearing 17 due to factors such as machining accuracy errors. This results in a more flexible structure and a more rational design.

[0031] More specifically, several positioning grooves are provided on the inner side of the bottom of the housing 1. These positioning grooves are arranged in a circular array around the axis of the central hole 11, achieving a uniform distribution of the positioning grooves on the inner side of the housing 1. Preferably, three positioning grooves are provided, and the three positioning grooves are arranged in an equilateral triangle. At the same time, several positioning protrusions corresponding to the positioning grooves are provided on the side of the oil distribution plate 4 away from the cylinder body 6. When the oil distribution plate 4 is assembled into the inner cavity of the housing 1, the side of the oil distribution plate 4 with the positioning protrusions abuts against the bottom of the housing 1. The mutual interlocking of the positioning protrusions and positioning grooves ensures the accuracy of the position of the oil distribution plate 4 on the bottom of the housing 1. This ensures that the oil inlet 12 and oil outlet 13 on the housing 1 can accurately correspond to and communicate with the oil inlet window and oil outlet window on the oil distribution plate 4, preventing misalignment. At the same time, it also provides conditions for ensuring the positional stability of the oil distribution plate 4 during subsequent use. Furthermore, each positioning slot has a guide ramp at its opening, and a guide slope that cooperates with the guide ramp is provided at the edge of the positioning protrusion. That is, when the oil distribution plate 4 is installed in the inner cavity of the housing 1, automatic alignment can be achieved through the cooperation of the guide ramp and the guide ramp, which improves the ease of assembly.

[0032] More specifically, several radially arranged oil guide grooves are provided on the surface of the oil distribution plate 4 that contacts the cylinder body 6. Each oil guide groove covers the spherical surface of the oil distribution plate 4 and is connected to the central hole 11. Furthermore, when the cylinder body 6 rotates, each plunger cavity of the cylinder body 6 is connected to each oil guide groove. That is, when the plunger pump is working, as oil enters and exits from the suction port and outlet port 13, the oil passes between the oil distribution plate 4 and the cylinder body 6, and through the corresponding oil guide groove in the cylinder body 6. The oil stored in the cylinder body 6 flows through the oil guide groove, thus covering the entire spherical surface. This not only achieves continuous lubrication between the cylinder body 6 and the oil distribution plate 4, reducing wear between them and extending service life, eliminating the need for subsequent lubrication and achieving maintenance-free operation, but also guides a small amount of oil to the central hole 11 through the oil guide grooves to provide lubrication for the support bearing 17, similarly extending service life and reducing the need for later maintenance. Preferably, the depth of the oil guide groove is less than 0.2mm, which makes the oil guide groove shallower and avoids the problem of obvious undulation of the spherical contact surface of the oil distribution plate 4 due to the arrangement of the oil guide groove. At the same time, it also reduces the amount of oil used for lubrication and reduces the risk of leakage.

[0033] The inverted quantitative plunger pump provided in this embodiment includes a housing 1, a rear cover 2, a pump core, a swashplate 3, and a distribution plate 4. By directly arranging the inlet 12 and outlet 13 on the bottom of the housing 1, and by abutting the swashplate 3 against the rear cover 2, and by placing the distribution plate 4 against the bottom of the housing 1 and communicating with the inlet 12 and outlet 13, and by placing the cylinder 6, plunger 7, and other structures of the pump core assembly between the distribution plate 4 and the swashplate 3, the swashplate 3 and the pump core are integrated within the housing 1. The inverted installation allows the oil inlet 12 and oil outlet 13 to be directly installed using the thick bottom of the housing 1 itself, eliminating the need to thicken the rear cover 2 to install the oil inlet 12 and oil outlet 13. This reduces the thickness of the rear cover 2, thereby avoiding space occupation in the length direction and increasing the power density ratio of the plunger pump. In addition, the surface where the oil distribution plate 4 and the cylinder block 6 contact is set as a spherical surface, realizing spherical flow distribution and effectively improving the stability of the plunger pump under high pressure conditions.

[0034] The above are merely preferred embodiments of the present utility model and are not intended to limit the implementation methods and protection scope of the present utility model. Those skilled in the art should realize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An inverted fixed displacement plunger pump, comprising a housing, a back cover, a pump core, a swash plate and an oil distribution plate, the housing is arranged in a barrel shape, the back cover is installed at the barrel opening of the housing, the pump core and the oil distribution plate are both installed in the barrel inner cavity of the housing, characterized in that, The pump core comprises a transmission shaft, a cylinder body, a plunger and a sliding shoe, a through central hole is formed in the bottom of the shell barrel, one end of the transmission shaft is rotatably installed in the central hole and extends into the barrel inner cavity of the shell, the cylinder body with a plurality of plunger cavities is sleeved on the transmission shaft, one plunger is slidably arranged in each plunger cavity, the swash plate is installed on the rear cover and abuts against each plunger through the sliding shoe, an oil inlet and an oil outlet are formed in the bottom of the barrel inner cavity of the shell and communicate with the barrel inner cavity, the oil distribution disc is arranged at one end of the barrel inner cavity of the shell close to the bottom, the oil distribution disc is provided with an oil inlet window and an oil outlet window which respectively communicate with the oil inlet and the oil outlet, the side of the cylinder body away from the swash plate abuts against the oil distribution disc, and the surface of the oil distribution disc abutting against the cylinder body is arranged as a spherical surface.

2. The inverted positive displacement piston pump of claim 1 wherein, The oil inlet and the oil outlet are symmetrically arranged on both sides of the bottom of the barrel of the shell.

3. The inverted positive displacement piston pump of claim 1 wherein, The inner side and the outer side of the bottom of the barrel of the shell and located at the central hole are respectively provided with a support hole and a sealing hole coaxially arranged with the central hole, an oil seal is arranged in the sealing hole, a support bearing is arranged in the support hole, and the oil seal and the support bearing are both sleeved on the transmission shaft.

4. The inverted positive displacement piston pump of claim 1 wherein, A recess is formed in the center of the rear cover close to the side of the shell, one end of the transmission shaft extending into the barrel inner cavity of the shell extends into the recess, at the same time, an auxiliary bearing is arranged in the recess and sleeved on one end of the transmission shaft extending into the recess.

5. The inverted positive displacement piston pump of claim 1 wherein, A plurality of limiting holes are formed in the rear cover close to the side of the shell, the side of the swash plate away from the sliding shoe abuts against the side surface of the rear cover with the limiting holes, and a plurality of matching holes corresponding to the limiting holes are formed in the side of the swash plate opposite to the rear cover, and a limiting pin is arranged between the matching hole and the corresponding limiting hole.

6. The inverted positive displacement piston pump of claim 1 wherein, A sealing gasket is arranged between the rear cover and the barrel opening of the shell.

7. The inverted positive displacement piston pump of claim 3 wherein, A recess hole is formed in the center of the oil distribution disc to accommodate the transmission shaft, and the recess hole is a stepped hole, the large cross-section hole of the stepped hole is located on the side of the oil distribution disc away from the cylinder body, at the same time, the stepped surface of the stepped hole abuts against the outer ring of the support bearing.

8. The inverted positive displacement piston pump of claim 3 wherein, A limiting ridge is arranged on the outer wall of one end of the transmission shaft extending into the barrel inner cavity of the shell, one side of the limiting ridge abuts against the inner ring of the support bearing, and an adjusting gasket is arranged between the limiting ridge and the support bearing.

9. The inverted positive displacement piston pump of claim 1 wherein, The inner side of the bottom of the barrel of the shell is annularly arranged with a plurality of positioning grooves with the axis of the central hole as the center, a plurality of positioning protrusions corresponding to the positioning grooves are arranged on the side of the oil distribution disc away from the cylinder body, and a guide slope is arranged on the edge of each positioning protrusion and matched with the guide slope of the positioning groove.

10. The inverted positive displacement piston pump of claim 1 wherein, A plurality of oil guide grooves are arranged on the surface of the oil distribution disc contacting the cylinder body along the radial direction, and each plunger cavity of the cylinder body communicates with each oil guide groove when the cylinder body rotates.

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