Piston motion components for hydraulic piston pumps

Abstract

A piston motion assembly for a hydraulic piston pump includes a piston rod and a piston. The piston rod is provided with a pressure relief guide groove and multiple pressure building guide grooves. Tapered portions are respectively provided at both ends of the pressure building guide grooves and the pressure relief guide grooves. This invention, by providing tapered portions at both ends of the pressure building guide grooves and the pressure relief guide grooves on the piston rod, and by adding a buffer joint in the direction of piston rod movement, ensures the smoothness of the piston and other moving parts during movement, thereby improving the service life of the components and the entire pump. The extended piston design reduces the pressure difference across the outer metal seal, extending the service life of the seal.

Description

Technical Field

[0001] This utility model relates to a piston motion component for a hydraulic piston pump, belonging to the technical field of rodless oil and gas extraction equipment manufacturing. Background Technology

[0002] Hydraulic piston pumps are an important branch of rodless well drainage equipment and a highly efficient mechanical drainage method. In certain situations, hydraulic piston pumps have proven irreplaceable. With the increasing exploitation of oil and gas reservoirs such as shale gas and coalbed methane, the depth of oil and gas reservoirs is constantly increasing, and the amount of water accumulated in wells is gradually increasing. Conventional drainage equipment, such as foam lift and velocity tubing, are becoming increasingly inadequate. Hydraulic piston pumps, due to their high efficiency, applicability to deep and deviated well operations, and mechanical drainage methods, are widely used in oil and gas field drainage operations.

[0003] However, hydraulic piston pumps operate by reversing direction downhole, and the reversing impact can affect the normal use of the pump. Traditional piston moving components are prone to impact when moving to the end of the stroke, resulting in poor stability and reducing the service life of the entire pump. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a piston motion assembly for a hydraulic piston pump, which addresses the shortcomings of the prior art. By setting tapered portions at both ends of the pressure building and pressure relief guide grooves of the piston rod, and adding a buffer joint in the direction of piston rod movement, the stability of moving parts such as the piston and reversing valve core during movement is ensured, and the service life of the components and the entire pump is improved. The design of the extended piston reduces the pressure difference on both sides of its outer metal seal, extending the service life of the seal.

[0005] This utility model provides a piston motion assembly for a hydraulic piston pump. The piston motion assembly includes a piston rod and a piston. The piston rod is provided with a pressure relief guide groove and a plurality of pressure building guide grooves. The two ends of the pressure building guide groove and the pressure relief guide groove are respectively provided with a tapered portion.

[0006] To introduce different pressures into the pressure control chamber of the reversing valve, the pressure relief guide groove is an annular groove formed on the outside of the piston rod and coaxially arranged with the piston rod. The length of the pressure relief guide groove is less than the length of the reversing valve core of the hydraulic piston pump. The pressure building guide groove is a strip-shaped groove formed on the outside of the piston rod. The length direction of the pressure building guide groove is parallel to the axial direction of the piston rod. Multiple pressure building guide grooves are evenly spaced along the circumference of the piston rod. The length of the pressure building guide groove is greater than the length of the reversing valve core of the hydraulic piston pump.

[0007] To further reduce impact and achieve speed regulation, the piston motion assembly also includes a buffer joint coaxially arranged with the piston rod. The buffer joint is located on the extension line of the piston rod axis. The buffer joint is provided with a rod head receiving cavity and a throttling cavity in sequence along the direction away from the piston rod. The inner diameter of the throttling cavity is smaller than the inner diameter of the rod head receiving cavity.

[0008] In order to better fix the piston and achieve a seal between the piston and the piston rod, the piston rod is provided with a rod head, a first mounting part and a second mounting part in sequence from the outside to the inside along the axial direction. The diameter of the second mounting part is smaller than the diameter of the piston rod, and the end of the second mounting part away from the first mounting part is provided with a piston sealing cone surface.

[0009] Preferably, the piston is mounted on both ends of the piston rod by locking members, the locking members are mounted on the first mounting part, and the piston is mounted on the second mounting part.

[0010] To achieve a better sealing effect, the piston has multiple first sealing element mounting grooves on its outer side and multiple second sealing element mounting grooves on its inner side. Both the first and second sealing element mounting grooves are annular and arranged at intervals along the axial direction of the piston. A first sealing element is disposed in each of the first and second sealing element mounting grooves, and a second sealing element is disposed in each of the second sealing element mounting grooves. The first sealing element is a metal sealing element, and the second sealing element is a non-metallic sealing element.

[0011] Preferably, the piston is an extended piston, with a plurality of first sealing element mounting grooves on the outer side and a plurality of second sealing element mounting grooves on the inner side. The plurality of first sealing element mounting grooves and the plurality of second sealing element mounting grooves are annular and arranged at intervals along the axial direction of the extended piston. A first sealing element is provided in the first sealing element mounting groove, and a second sealing element is provided in the second sealing element mounting groove.

[0012] To extend the service life of the seal, the extended piston includes a piston portion and a throttling connector arranged coaxially. The piston portion is divided into a sealing portion, a piston rod connecting portion, a throttling connector connecting portion, a flow channel groove portion, and a fluid inflow portion in sequence along the axial direction. The sealing portion, the piston rod connecting portion, the throttling connector connecting portion, and the flow channel groove portion are all provided with a first seal mounting groove on their outer sides, and a second seal mounting groove is provided in the sealing portion. The piston rod connecting portion and the throttling connector connecting portion are both provided with internal threads. The diameter of the fluid inflow portion is smaller than the diameter of the flow channel groove portion. The fluid inflow portion is provided with a plurality of first radial holes, which are evenly distributed circumferentially. The flow channel groove portion is provided with a plurality of annular flow channel grooves spaced axially along its outer side. Each flow channel groove is provided with a plurality of second radial holes evenly distributed circumferentially. The first mounting portion is provided with external threads on its outer side. The throttling connector is divided into a connector part, abutment part, spiral groove part and piston part connecting part in sequence along the axial direction; the piston part connecting part is provided with external thread, the spiral groove part is provided with a spiral groove on the outside, the diameter of the abutment part is larger than the diameter of the spiral groove part, and the shape of the connector part is the same as the shape of the rod head.

[0013] In summary, this utility model ensures the stability of moving parts such as the piston and reversing valve core during movement by setting tapered portions at both ends of the pressure building and pressure relief guide grooves of the piston rod, and by adding a buffer joint in the direction of piston rod movement, thereby improving the service life of the components and the entire pump. The design of the extended piston reduces the pressure difference on both sides of its outer metal seal, thus extending the service life of the seal.

[0014] The technical solution of this utility model will be described in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0015] Figure 1 This is a cross-sectional view of the piston motion assembly;

[0016] Figure 2 for Figure 1 A magnified view of a portion of the image;

[0017] Figure 3 This is a schematic diagram of the piston rod structure;

[0018] Figure 4 This is a schematic diagram of the structure of the buffer joint and piston rod;

[0019] Figure 5 This is a schematic diagram of the extended piston structure;

[0020] Figure 6 A cross-sectional view of the extended piston;

[0021] Figure 7This is a schematic diagram of the throttling connector.

[0022] [Explanation of Labels in the Attached Image]

[0023] 2000 Piston Motion Components

[0024] 2100 piston rod

[0025] 2110 club head

[0026] 2120 First Installation Department

[0027] 2130 Second Installation Department

[0028] 2131 Piston Sealing Cone

[0029] 2140 pressure relief guide channel

[0030] 2150 pressure-building guide channel

[0031] 2200 piston

[0032] 2210 First Seal Mounting Groove

[0033] 2220 Second Seal Mounting Groove

[0034] 2211 First Seal

[0035] 2221 Second Seal

[0036] 2300 locking parts

[0037] 2400 buffer connector

[0038] 2410 clubhead housing

[0039] 2420 Throttling Cavity

[0040] 2500 Extended Piston

[0041] 2510 Piston Section

[0042] 2501 Sealing Section

[0043] 2502 Piston Rod Connection

[0044] 2503 Throttling Connector Connection Part

[0045] 2504 flow channel groove section

[0046] 2505 Fluid Inlet Section

[0047] 2511 internal thread

[0048] 2512 First radial hole

[0049] 2513 Second Radial Hole

[0050] 2514 flow channel

[0051] 2520 Throttling Connector

[0052] 2591 Connector

[0053] 2592 reached the top

[0054] 2593 Spiral Groove Section

[0055] 2594 Piston Connection Section

[0056] 2521 external thread

[0057] 2522 Spiral Groove

[0058] 2523 mounting holes Detailed Implementation

[0059] Figure 1 This is a cross-sectional view of the piston motion assembly; Figure 2 for Figure 1 A magnified view of a portion of the image; Figure 3 This is a schematic diagram of the piston rod structure; Figure 4 This is a schematic diagram of the buffer joint and piston rod. Figures 1 to 4 As shown, this utility model provides a piston motion assembly 2000 for a hydraulic piston pump, the piston motion assembly 2000 including a piston rod 2100 and a piston 2200. The piston rod 2100 partially passes through the reversing valve core of the hydraulic piston pump.

[0060] Specifically, the piston rod 2100 has a rod head 2110, a first mounting portion 2120, and a second mounting portion 2130 sequentially arranged at both ends along the axial direction from the outside to the inside (from both ends of the piston rod 2100 towards the middle of the piston rod 2100). The piston 2200 is mounted at both ends of the piston rod 2100 via locking members 2300. Specifically, the locking members 2300 are mounted on the first mounting portion 2120 and are used to fix the piston 2200, which is mounted on the second mounting portion 2130. The piston rod 2100 can drive both pistons 2200 to move simultaneously.

[0061] The piston 2200 has multiple first seal mounting grooves 2210 on its outer side and multiple second seal mounting grooves 2220 on its inner side. Both the multiple first seal mounting grooves 2210 and the multiple second seal mounting grooves 2220 are annular and arranged at intervals along the axial direction of the piston 2200. A first seal 2211 is disposed in the first seal mounting groove 2210, and a second seal 2221 is disposed in the second seal mounting groove 2220.

[0062] To achieve a better sealing effect, the first sealing element 2211 is a metal sealing element and the second sealing element 2221 is a non-metallic sealing element, thereby achieving the sealing between the piston and the pump barrel of the hydraulic piston pump as well as the sealing of the piston inner bore.

[0063] To better secure the piston 2200 and achieve a seal between the piston 2200 and the piston rod 2100, the diameter of the second mounting portion 2130 is smaller than the diameter of the piston rod 2100. Furthermore, the end of the second mounting portion 2130 away from the first mounting portion 2120 is provided with a piston sealing cone surface 2131. That is, the diameter of the end of the second mounting portion 2130 away from the first mounting portion 2120 increases linearly in the direction away from the first mounting portion 2120 until it is the same as the diameter of the piston rod 2100. This combination of the second seal 2221 and the piston sealing cone surface 2131 enhances the sealing reliability.

[0064] Figure 5 This is a schematic diagram of the extended piston structure; Figure 6 A cross-sectional view of the extended piston; Figure 7 This is a schematic diagram of a throttling connector. Figures 5 to 7 As shown, in order to extend the service life of the seal and extend the operating time of the equipment, this utility model also provides an extended piston 2500, which can be used to replace the piston 2200 mentioned above.

[0065] Similar to piston 2200, the extended piston 2500 also has multiple first seal mounting grooves on its outer side and multiple second seal mounting grooves on its inner side. A first seal 2211 is installed in the first seal mounting groove, and a second seal 2221 is installed in the second seal mounting groove. However, the extended piston 2500 is longer than the piston 2200 and does not require locking member 2300 for fixation.

[0066] Specifically, the extended piston 2500 includes a piston portion 2510 and a throttle connector 2520 arranged coaxially. The length of the piston portion 2510 is greater than the total length of the rod head 2110, the first mounting portion 2120, and the second mounting portion 2130.

[0067] Since the length of the extended piston 2500 is longer than that of the piston 2200, more first seal mounting slots 2210 can be set on the outside. Users can flexibly select and use them according to actual conditions, increasing or decreasing the number of seals to ensure sealing effect.

[0068] The piston portion 2510 is divided into a sealing portion 2501, a piston rod connecting portion 2502, a throttling connector connecting portion 2503, a flow channel groove portion 2504, and a fluid inflow portion 2505 along the axial direction. The sealing portion 2501, the piston rod connecting portion 2502, the throttling connector connecting portion 2503, and the flow channel groove portion 2504 are all provided with a first sealing element mounting groove 2210 on their outer sides.

[0069] The second sealing element mounting groove is provided in the sealing part 2501; the piston rod connecting part 2502 and the throttling connector connecting part 2503 are both provided with internal threads 2511, which are used to connect the piston rod 2100 and the throttling connector 2520 respectively; the diameter of the fluid inflow part 2505 is smaller than the diameter of the flow channel groove part 2504.

[0070] A plurality of first radial holes 2512 are provided at the fluid inlet 2505, and the plurality of first radial holes 2512 are evenly distributed circumferentially. A plurality of (three shown in the figure) annular flow channel grooves 2514 are provided at axial intervals on the outer side of the flow channel groove 2504, and a plurality of second (one group) radial holes 2513 are provided at each flow channel groove 2514, and the plurality of second radial holes 2513 are evenly distributed circumferentially.

[0071] To engage with the internal thread in the piston rod connection portion of the extended piston 2500, the outer side of the first mounting portion 2120 is provided with an external thread (not shown in the figure). The extended piston 2500 can be fixed to the piston rod 2100 through the threaded connection between the internal thread in the piston rod connection portion and the external thread on the outer side of the first mounting portion 2120. Similarly, the throttle connector 2520 is also provided with an external thread 2521 on its outer side. The throttle connector 2520 can be fixed to the extended piston 2500 through the threaded connection between the internal thread in the piston rod connection portion and the external thread 2521 on the outer side of the throttle connector 2520.

[0072] The throttle connector 2520 is divided into a connector part 2591, abutment part 2592, spiral groove part 2593 and piston part connecting part 2594 along the axial direction.

[0073] The aforementioned external thread 2521 is provided at the piston connection portion 2594. A spiral groove 2522 with a cross-section of, for example, triangular is provided on the outer side of the spiral groove portion 2593. The diameter of the top portion 2592 is larger than the diameter of the spiral groove portion 2593, thereby facilitating positioning when the throttle connector 2520 is installed on the piston portion 2510. The shape of the connector portion 2591 is the same as the shape of the rod head 2110 of the piston rod 2100, so that even after the piston 2200 is replaced with an extended piston 2500, it can still be used in conjunction with other components (such as the buffer connector 2400 described later).

[0074] This invention achieves throttling and pressure equalization through the first radial hole 2512 and the second radial hole 2513. Specifically, during actual operation, because the diameter of the fluid inlet 2505 is small, the multiple first radial holes 2512 at the fluid inlet 2505 are connected to the cavity (such as the motor cavity). The high-pressure fluid in the motor cavity flows into the space between the throttling connector 2520 and the piston 2510 through the first radial holes 2512. Because the spiral groove 2522 is provided on the outer side of the spiral groove 2593, the gap between the throttling connector 2520 and the piston 2510 is very small. The high-pressure fluid enters the multiple second radial holes 2513 at different positions (groups) along the spiral groove 2522, and then enters different flow channel grooves 2514. The fluid entering the second radial hole 2513 of different groups flows through the spiral groove 2522 for different lengths. Since the cross-sectional size of the spiral groove 2522 is very small, the fluid will be throttled and generate flow resistance when passing through the slender hole. Through this process, the pressure of different flow channels is reduced step by step, thereby reducing the pressure difference on both sides of the first seal 2211 (metal seal) at different positions. In addition, the sealing pressure difference of the metal seal located outside the sealing part 2501, piston rod connection part 2502 and throttling connector connection part 2503 is also reduced. The reduction of pressure difference reduces the deformation and contact force of the first seal 2211 under pressure during operation, slows down the wear rate and thus prolongs the service life.

[0075] To facilitate the installation of the throttle connector 2520 on the piston portion 2510, a mounting hole 2523 (e.g., a hexagonal hole) is provided in the middle of the connector portion 2591 of the throttle connector 2520, so that the user can use a tool (e.g., an Allen wrench) to install it on the piston portion 2510.

[0076] The piston rod 2100 is also provided with a pressure relief guide groove 2140 and multiple pressure build-up guide grooves 2150.

[0077] The pressure relief guide groove 2140 is an annular groove formed on the outside of the piston rod 2100 and coaxially arranged with the piston rod 2100. The length of the pressure relief guide groove 2140 is less than the length of the reversing valve core of the hydraulic piston pump.

[0078] The pressure-building guide groove 2150 is a strip-shaped groove formed on the outside of the piston rod 2100. The length direction of the pressure-building guide groove 2150 is parallel to the axial direction of the piston rod 2100, and multiple pressure-building guide grooves 2150 are evenly distributed around the circumference of the piston rod 2100. The length of the pressure-building guide groove 2150 is greater than the length of the reversing valve core of the hydraulic piston pump. The multiple pressure-building guide grooves 2150 not only serve the function of fluid conduction but also provide guidance for the reversing valve core of the hydraulic piston pump. That is, in this utility model, the design of the pressure-building guide groove 2150 has two functions: guiding support and fluid conduction.

[0079] It should be added that the position of the pressure building guide channel 2150 should be such that the pressure building guide channel 2150 can enter the reversing valve core of the hydraulic piston pump when the piston rod 2100 moves, while the position of the pressure relief guide channel 2140 should be such that the pressure relief guide channel 2140 will not enter the reversing valve core of the hydraulic piston pump when the piston rod 2100 moves.

[0080] When the piston rod 2100 is in different positions, the pressure relief guide channel 2140 and the pressure building guide channel 2150 can respectively connect the pressure control chamber of the hydraulic piston pump's reversing valve to the power fluid chamber or the waste fluid chamber of the hydraulic piston pump, thereby introducing different pressures into the pressure control chamber of the reversing valve. This causes the force state of the reversing valve core to change alternately, realizing the movement of the reversing valve core. Furthermore, it ensures that during the movement of the reversing valve core, different conductive connection forms are created on the radial holes of the remaining reversing valve sleeves to achieve the reversing process. Specifically, the pressure building guide channel 2150 can connect the pressure control chamber of the hydraulic piston pump's reversing valve to the power fluid chamber of the hydraulic piston pump, and the pressure relief guide channel 2140 can connect the pressure control chamber of the hydraulic piston pump's reversing valve to the waste fluid chamber of the hydraulic piston pump.

[0081] To reduce the impact that occurs when the piston moving assembly 2000 reaches the end of its stroke, tapered portions 2160 are provided at both ends of the pressure-building guide channel 2150 and the pressure-relief guide channel 2140. Specifically, the diameter of the two ends (tapered portions 2160) of the pressure-building guide channel 2150 increases linearly away from the pressure-building guide channel 2150, and the diameter of the two ends (tapered portions 2160) of the pressure-relief guide channel 2140 increases linearly away from the pressure-relief guide channel 2140. The inclined surface of the tapered portion 2160 allows the fluid flow area to gradually decrease, thereby buffering the movement of the reversing valve.

[0082] To further reduce impact and achieve speed regulation, the piston motion assembly 2000 also includes a buffer joint 2400 coaxially arranged with the piston rod 2100. The buffer joint 2400 is located on the extension line of the axis of the piston rod 2100. This utility model does not limit the specific setting position of the buffer joint 2400, as long as its setting position allows the rod head 2110 of the piston rod 2100 to periodically enter the buffer joint 2400 when the piston rod 2100 of the piston motion assembly 2000 moves. Its setting position can be determined according to the equipment structure, for example, it can be installed on other components of the hydraulic piston pump (such as the multi-functional joint 4000).

[0083] The buffer joint 2400 is provided with a rod head receiving cavity 2410 and a throttling cavity 2420 in sequence along the direction away from the piston rod 2100. The inner diameter of the throttling cavity 2420 is smaller than the inner diameter of the rod head receiving cavity 2410. The shape of the rod head receiving cavity 2410 corresponds to the shape of the rod head 2110.

[0084] Figure 4 The arrows in the diagram indicate the direction of liquid flow. When the rod head 2110 of the piston rod 2100 enters the buffer joint 2400, the liquid outflow area of ​​the buffer joint 2400 decreases because the inner diameter of the throttling chamber 2420 is smaller than the inner diameter of the rod head receiving chamber 2410. This throttles the liquid, increasing the pressure resistance and thus raising the pressure in the chamber. This pressure buildup creates a reverse pressure, increasing the resistance experienced by the piston rod 2100 during its movement. This is used to decelerate the piston 2200 and piston rod 2100 as a whole, thereby reducing or avoiding the impact generated during the piston's movement to the end, and achieving throttling speed regulation of the piston movement assembly 2000.

[0085] When the piston 2200 is replaced with the extended piston 2500, since the shape of the connector 2591 of the throttling connector 2520 of the extended piston 2500 is the same as the shape of the rod head 2110 of the piston rod 2100, the connector 2591 can still achieve throttling speed regulation of the piston movement assembly 2000 after entering the buffer connector 2400.

[0086] In summary, this utility model ensures the stability of moving parts such as the piston and reversing valve core during movement by setting tapered portions at both ends of the pressure building and pressure relief guide grooves of the piston rod, and by adding a buffer joint in the direction of piston rod movement, thereby improving the service life of the components and the entire pump. The design of the extended piston reduces the pressure difference on both sides of its outer metal seal, thus extending the service life of the seal.

Claims

1. A piston motion assembly for a hydraulic piston pump, characterized in that, The piston motion assembly includes a piston rod and a piston. The piston rod is provided with a pressure relief guide groove and a plurality of pressure building guide grooves. The two ends of the pressure building guide groove and the pressure relief guide groove are respectively provided with a tapered portion.

2. The piston motion assembly for a hydraulic piston pump as described in claim 1, characterized in that, The pressure relief guide groove is an annular groove formed on the outside of the piston rod and coaxially arranged with the piston rod. The length of the pressure relief guide groove is less than the length of the reversing valve core of the hydraulic piston pump. The pressure building guide groove is a strip-shaped groove formed on the outside of the piston rod. The length direction of the pressure building guide groove is parallel to the axial direction of the piston rod. Multiple pressure building guide grooves are evenly spaced along the circumference of the piston rod. The length of the pressure building guide groove is greater than the length of the reversing valve core of the hydraulic piston pump.

3. The piston motion assembly for a hydraulic piston pump as described in claim 1, characterized in that, The piston motion assembly also includes a buffer joint coaxially arranged with the piston rod. The buffer joint is located on the extension line of the piston rod axis. The buffer joint is provided with a rod head receiving cavity and a throttling cavity in sequence along the direction away from the piston rod. The inner diameter of the throttling cavity is smaller than the inner diameter of the rod head receiving cavity.

4. The piston motion assembly for a hydraulic piston pump as described in claim 1, characterized in that, The piston rod has a rod head, a first mounting part, and a second mounting part arranged sequentially from the outside to the inside along the axial direction at both ends. The diameter of the second mounting part is smaller than the diameter of the piston rod, and a piston sealing cone surface is provided at the end of the second mounting part away from the first mounting part.

5. The piston motion assembly for a hydraulic piston pump as described in claim 4, characterized in that, The piston is mounted on both ends of the piston rod by locking members, the locking members are mounted on the first mounting part, and the piston is mounted on the second mounting part.

6. The piston motion assembly for a hydraulic piston pump as described in claim 5, characterized in that, The piston has multiple first seal mounting grooves on its outer side and multiple second seal mounting grooves on its inner side. The multiple first seal mounting grooves and multiple second seal mounting grooves are annular and arranged at intervals along the axial direction of the piston. A first seal is provided in the first seal mounting groove and a second seal is provided in the second seal mounting groove.

7. The piston motion assembly for a hydraulic piston pump as described in claim 6, characterized in that, The first seal is a metal seal, and the second seal is a non-metal seal.

8. The piston motion assembly for a hydraulic piston pump as described in claim 4, characterized in that, The piston is an extended piston. The extended piston has multiple first sealing element mounting grooves on its outer side and multiple second sealing element mounting grooves on its inner side. The multiple first sealing element mounting grooves and the multiple second sealing element mounting grooves are all annular and arranged at intervals along the axial direction of the extended piston. A first sealing element is provided in the first sealing element mounting groove and a second sealing element is provided in the second sealing element mounting groove.

9. The piston motion assembly for a hydraulic piston pump as described in claim 8, characterized in that, The extended piston includes a piston portion and a throttling connector arranged coaxially. The piston portion is divided into a sealing portion, a piston rod connecting portion, a throttling connector connecting portion, a flow channel groove portion, and a fluid inflow portion in sequence along the axial direction. The sealing portion, the piston rod connecting portion, the throttling connector connecting portion, and the flow channel groove portion are all provided with a first sealing element mounting groove on their outer sides, and a second sealing element mounting groove is provided in the sealing portion. The piston rod connecting portion and the throttling connector connecting portion are both provided with internal threads. The diameter of the fluid inflow portion is smaller than the diameter of the flow channel groove portion. The fluid inflow portion is provided with a plurality of first radial holes, which are evenly distributed circumferentially. The flow channel groove portion is provided with a plurality of annular flow channel grooves spaced axially along its outer side. Each flow channel groove is provided with a plurality of second radial holes evenly distributed circumferentially. The first mounting portion is provided with external threads on its outer side.

10. The piston motion assembly for a hydraulic piston pump as described in claim 9, characterized in that, The throttling connector is divided into a connector part, abutment part, spiral groove part and piston part connecting part in sequence along the axial direction; the piston part connecting part is provided with external thread, the spiral groove part is provided with a spiral groove on the outside, the diameter of the abutment part is larger than the diameter of the spiral groove part, and the shape of the connector part is the same as the shape of the rod head.

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