A plunger return device and a plunger pump

Abstract

A plunger return device and a plunger pump are disclosed. The plunger return device includes an eccentric shaft, a rotating assembly, a first plunger, a second plunger, and a connecting member. The rotating assembly includes a rotating member, a moving member, and a rolling member. The rolling member is located between the rotating member and the moving member. The rotating member is connected to the eccentric shaft. The moving member includes an outer peripheral surface. The outer peripheral surface of the moving member includes a first outer peripheral portion and a second outer peripheral portion. The first plunger is fitted to the first outer peripheral portion. The second plunger is fitted to the second outer peripheral portion. The connecting member connects the first plunger and the second plunger. The distance between the first outer peripheral portion and a center axis of the eccentric shaft in a radial direction is different from the distance between the second outer peripheral portion and the center axis of the eccentric shaft in the radial direction. In this way, the wear of the first plunger and the second plunger is reduced.

Description

Technical Field

[0001] This application relates to the field of plunger pump technology, and in particular to a plunger return device and a plunger pump. Background Technology

[0002] Hydraulic pumps, as the power components of hydraulic systems, play a vital role. Piston pumps achieve oil suction and discharge by changing the volume of the piston chamber through the reciprocating linear motion of the piston within the chamber. However, some radial piston pumps exhibit abnormal wear between the piston end face and the eccentric shaft, and the return mechanism uses springs for piston return, resulting in low spring life and reliability. Similarly, some axial piston pumps show abnormal wear between the swashplate rocker arm and the piston end face, all of which severely impact the reliability and lifespan of the piston pump.

[0003] Therefore, in view of the above situation, there is a need to provide a plunger return device and a plunger pump to at least partially solve the existing problems. Summary of the Invention

[0004] The summary of this application introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. This summary is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0005] According to a first aspect of this application, a plunger return device is provided, the plunger return device comprising:

[0006] Eccentric shaft;

[0007] A rotating assembly includes a rotating member, a moving member, and a rolling member, wherein the rolling member is located between the rotating member and the moving member, the rotating member is connected to the eccentric shaft, and the moving member includes an outer peripheral surface, the outer peripheral surface of the moving member including a first outer peripheral portion and a second outer peripheral portion;

[0008] A first plunger and a second plunger are arranged opposite each other along the radial direction of the eccentric shaft. The first plunger is in contact with the first outer peripheral portion, and the second plunger is in contact with the second outer peripheral portion.

[0009] A connecting member, which connects the first plunger and the second plunger,

[0010] The distance between the first outer peripheral portion and the central axis of the eccentric shaft along the radial direction is different from the distance between the second outer peripheral portion and the central axis of the eccentric shaft along the radial direction.

[0011] According to the plunger return device of this application, the plunger return device includes an eccentric shaft, a rotating assembly, a first plunger, a second plunger, and a connecting member. The rotating assembly includes a rotating member, a moving member, and a rolling member. The rolling member is located between the rotating member and the moving member. The rotating member is connected to the eccentric shaft. The moving member includes an outer peripheral surface, which includes a first outer peripheral portion and a second outer peripheral portion. The first plunger and the second plunger are arranged opposite to each other along the radial direction of the eccentric shaft. The first plunger is in contact with the first outer peripheral portion, and the second plunger is in contact with the second outer peripheral portion. The connecting member connects the first plunger and the second plunger. The distance between the first outer peripheral portion and the central axis of the eccentric shaft along the radial direction is different from the distance between the second outer peripheral portion and the central axis of the eccentric shaft along the radial direction. This design features a simple structure and low manufacturing cost. It transforms sliding friction into rolling friction, reducing wear on the first and second plungers and avoiding abnormal wear and low reliability and lifespan issues. The connecting component rigidly connects the first and second plungers together, achieving synchronous movement and preventing jamming or failure that could cause the first and / or second plungers to fail to return to their original positions. This greatly improves the reliability and lifespan of the plunger return device.

[0012] Optionally, the rotation of the eccentric shaft drives the rotating assembly to move linearly between a first position and a second position, so that both the first plunger and the second plunger can move linearly along the radial direction.

[0013] The centerline of the rotating assembly located at the first position is spaced apart from the central axis of the eccentric shaft along the radial direction.

[0014] The centerline of the rotating assembly located in the second position is spaced apart from the central axis of the eccentric shaft along the radial direction.

[0015] Optionally, there is also a balance position between the first position and the second position.

[0016] The centerline of the rotating assembly, located in the equilibrium position, is on the same horizontal plane as the central axis of the eccentric shaft.

[0017] Optionally, both the first plunger and the second plunger are provided with annular grooves, and the connecting member includes a first free end, a second free end and an arc-shaped segment. The first free end and the second free end are connected through the arc-shaped segment. The first free end engages with the first plunger, and the second free end engages with the second plunger.

[0018] Optionally, the first free end includes a first slot, the second free end includes a second slot, one of the first slot and the second slot includes a first slot wall, and the two first slot walls are parallel to each other.

[0019] Optionally, the other of the first and second card slots includes a second slot wall having an inwardly protruding protrusion.

[0020] Optionally, the other of the first slot and the second slot includes a second slot wall and a second slot bottom. The second slot wall includes a first inclined segment and a second inclined segment. The first inclined segment extends inward from the second slot bottom, and the second inclined segment extends outward from the first inclined segment.

[0021] Optionally, the plunger return device further includes a first plunger cylinder and a second plunger cylinder, wherein the first plunger reciprocates linearly in the first plunger cylinder along the radial direction, and the second plunger reciprocates linearly in the second plunger cylinder along the radial direction.

[0022] This application also provides a plunger pump, which includes the plunger return device described above, and further includes a first chamber and a second chamber, wherein the first plunger is located in the first chamber and the second plunger is located in the second chamber.

[0023] According to the plunger pump of this application, the plunger pump includes the plunger return device described above. The plunger pump also includes a first chamber and a second chamber. The first plunger is located in the first chamber, and the second plunger is located in the second chamber. The plunger return device includes an eccentric shaft, a rotating assembly, a first plunger, a second plunger, and a connecting member. The rotating assembly includes a rotating member, a moving member, and a rolling member. The rolling member is located between the rotating member and the moving member. The rotating member is connected to the eccentric shaft. The moving member includes an outer peripheral surface, which includes a first outer peripheral portion and a second outer peripheral portion. The first plunger and the second plunger are arranged opposite each other along the radial direction of the eccentric shaft. The first plunger is in contact with the first outer peripheral portion, and the second plunger is in contact with the second outer peripheral portion. The connecting member connects the first plunger and the second plunger. The distance between the first outer peripheral portion and the central axis of the eccentric shaft along the radial direction is different from the distance between the second outer peripheral portion and the central axis of the eccentric shaft along the radial direction. This design features a simple structure and low manufacturing cost. It transforms sliding friction into rolling friction, reducing wear on the first and second plungers and avoiding abnormal wear and low reliability and lifespan issues. The connecting component rigidly connects the first and second plungers together, achieving synchronous movement and preventing jamming or failure that could cause the first and / or second plungers to fail to return to their original positions. This greatly improves the reliability and lifespan of the plunger return device.

[0024] Optionally, the plunger pump further includes a first port and a second port, the first port communicating with the first chamber and the second port communicating with the second chamber.

[0025] The first plunger moves toward the second plunger to draw liquid from the first port into the first chamber.

[0026] The second plunger moves away from the first plunger to discharge the liquid in the second chamber through the second port.

[0027] Optionally, the second plunger moves toward the first plunger to draw liquid from the second port into the second chamber.

[0028] The first plunger moves away from the second plunger to discharge the liquid in the first chamber through the first port.

[0029] Optionally, the plunger pump further includes a return oil chamber, in which the rotating assembly is disposed. The plunger pump also includes a low-pressure inlet, a first port, and a second port. The first port is connected to the first chamber, and the second port is connected to the second chamber. Both the first port and the second port are connected to the low-pressure inlet, and the return oil chamber is connected to the low-pressure inlet.

[0030] This application also provides a plunger return device, the plunger return device comprising:

[0031] rocker arm;

[0032] A rotating assembly, comprising a rotating member, a moving member, and a rolling member, wherein the rolling member is located between the rotating member and the moving member, and the rotating member is connected to the rocker arm;

[0033] A first plunger and a second plunger are disposed opposite to each other, and both the first plunger and the second plunger are in contact with the outer peripheral surface of the moving member;

[0034] The first plunger can move toward the second plunger to push both the moving member and the second plunger to move, so that the rotating member drives the rocker arm to swing.

[0035] According to the plunger return device of this application, the plunger return device includes a rocker arm, a rotating assembly, a first plunger, and a second plunger. The rotating assembly includes a rotating member, a moving member, and a rolling member. The rolling member is located between the rotating member and the moving member. The rotating member is connected to the rocker arm. The first plunger and the second plunger are arranged opposite to each other. Both the first plunger and the second plunger are in contact with the outer peripheral surface of the moving member. The first plunger can move in the direction of the second plunger to push both the moving member and the second plunger to move, so that the rotating member drives the rocker arm to swing. In this way, the structure is simple, the manufacturing cost is low, the wear on the first and second plungers is reduced, the problems of abnormal wear and low reliability and lifespan are avoided, and the reliability and lifespan of the plunger return device are greatly improved. Attached Figure Description

[0036] The following figures are included as part of this application for understanding the application. The figures illustrate embodiments of the application and their descriptions, serving to explain the apparatus and principles of the application. In the figures,

[0037] Figure 1 This is a cross-sectional schematic diagram of a plunger return device according to a preferred embodiment of this application;

[0038] Figure 2 for Figure 1 Another cross-sectional schematic diagram of the plunger return device shown;

[0039] Figure 3 For along Figure 1 A schematic diagram of the cross-section intercepted by line AA in the diagram;

[0040] Figure 4 for Figure 1 A schematic cross-sectional view of the connecting component shown;

[0041] Figure 5 For along Figure 4 A schematic diagram of one end face of the connecting member shown in the G1 direction;

[0042] Figure 6 For along Figure 4 A schematic diagram of the other end face of the connecting member shown in the G2 direction;

[0043] Figure 7 for Figure 5 A schematic diagram of another end face of the connecting member shown;

[0044] Figure 8 for Figure 6 A schematic diagram of another end face of the connecting member shown;

[0045] Figure 9 A plunger pump according to a preferred embodiment of this application;

[0046] Figure 10 for Figure 9 A schematic diagram of a cross-section of the plunger pump is shown below;

[0047] Figure 11 For along Figure 10 A schematic diagram of the rotation of the cross section intercepted by the centerline BB;

[0048] Figure 12 This is a cross-sectional schematic diagram of a plunger return device according to another preferred embodiment of this application.

[0049] Explanation of reference numerals in the attached figures:

[0050] 100: Plunger return device; 110: Eccentric shaft

[0051] 111: Outer peripheral surface of the moving component; 112: First outer peripheral portion

[0052] 113: Second outer periphery; 130: Rotating assembly

[0053] 131: Rotating component; 132: Moving component

[0054] 133: Rolling component; 141: First plunger

[0055] 142: Second plunger; 143: First plunger cylinder

[0056] 144: Second plunger cylinder; 150: Connecting component

[0057] 151: First free end; 152: Second free end

[0058] 153: Arc-shaped segment; 154: First slot

[0059] 155: Second slot 156: First slot wall

[0060] 157: Second groove wall; 158: Protrusion

[0061] 159: Bottom of the first trough 160: Bottom of the second trough

[0062] 161: First inclined section 162: Second inclined section

[0063] 163: First opening 164: Second opening

[0064] 170: Rocker arm; 171: End shaft

[0065] 172: Spring; 200: Piston Pump

[0066] 201: First chamber; 202: Second chamber

[0067] 203: First bite 204: Second bite

[0068] 205: Oil return chamber; 206: Pump base

[0069] 207: Adapter block; 208: Oil seal

[0070] 209: Retaining ring; 211: First check valve

[0071] 212: Second check valve; 213: Third check valve

[0072] 214: Fourth check valve; 221: First oil circuit

[0073] 222: Second oil circuit; 223: Return oil circuit Detailed Implementation

[0074] The following description provides numerous specific details to offer a more thorough understanding of this application. However, it will be apparent to those skilled in the art that this application can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described to avoid confusion with this application.

[0075] To fully understand this application, detailed descriptions will be provided below to illustrate it. Obviously, implementation of this application is not limited to the specific details familiar to those skilled in the art. Preferred embodiments of this application are described in detail below; however, other embodiments may exist besides these detailed descriptions and should not be construed as being limited to the embodiments set forth herein.

[0076] It should be understood that the terminology used herein is intended only to describe particular embodiments and is not intended to limit the scope of this application. The singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. When the terms “comprising” and / or “including” are used in this specification, they indicate the presence of the stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or combinations thereof. The terms “upper,” “lower,” “front,” “rear,” “left,” “right,” and similar expressions used in this application are for illustrative purposes only and are not intended to be limiting.

[0077] The ordinal numbers such as "first" and "second" used in this application are merely identifiers and have no other meaning, such as a specific order. In this application, unless otherwise expressly specified and limited, "above" or "below" a second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of a second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" of a second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0078] The specific embodiments of this application will be described in more detail below with reference to the accompanying drawings, which illustrate representative embodiments of this application and are not intended to limit this application.

[0079] Figure 1 and Figure 2 This application illustrates a preferred embodiment of a plunger return device 100. The plunger return device 100 includes an eccentric shaft 110, a rotating assembly 130, a first plunger 141, and a second plunger 142. The eccentric shaft 110 is rotatable and capable of outputting torque. The eccentric shaft 110 is configured as a rotating body. Rotation of the eccentric shaft 110 drives the first plunger 141 and the second plunger 142 to move. Specifically, the first plunger 141 and the second plunger 142 are capable of linear movement. Both the first plunger 141 and the second plunger 142 are cylindrical structures.

[0080] The rotating assembly 130 converts the rotational motion of the eccentric shaft 110 into linear motion. The rotating assembly 130 includes a rotating member 131, a moving member 132, and a rolling member 133, all of which are coaxially arranged. The rotating assembly 130 can be configured as a thrust bearing. Both the rotating member 131 and the moving member 132 can be configured as annular structures. The rolling member 133 is located between the rotating member 131 and the moving member 132. The rolling member 133 is configured as a spherical structure. The rotating assembly 130 includes multiple rolling members 133, which are located between the rotating member 131 and the moving member 132.

[0081] The rotating member 131 is connected to the eccentric shaft 110. The rotating member 131 can be sleeved on the outside of the eccentric shaft 110. The rotating member 131 and the eccentric shaft 110 can be engaged together. The rotation of the eccentric shaft 110 can drive the rotating member 131 to rotate. The rolling member 133 can roll along with the rotating member 131, so that the moving member 132 does not rotate.

[0082] like Figure 3 As shown, the eccentric shaft 110 includes a large portion and a small portion, with their central axes spaced apart. The large portion is located to the side of the small portion along the axial direction of the eccentric shaft 110. The central axis of the small portion coincides with the central axis O of the eccentric shaft 110. The radial dimension of the large portion along the eccentric shaft 110 is larger than that of the small portion. The dimensions of the portions of the large portion located on either side of the central axis O of the eccentric shaft 110 along the radial direction are different. The large portion is used to mount the rotating assembly 130.

[0083] The distances from different positions on the outer peripheral surface of the large-size portion of the eccentric shaft 110 to the central axis O of the eccentric shaft 110 are different. The distances from the outer peripheral surface of the large-size portion of the eccentric shaft 110 to the central axis O of the eccentric shaft 110 are unequal. The movement trajectory of the outer peripheral surface of the eccentric shaft 110 is an elliptical curve. The rotating assembly 130 is fitted onto the eccentric shaft 110. In particular, the rotating assembly 130 is fitted onto the large-size portion. The distances from different positions of the rotating member 131 along the radial direction of the eccentric shaft 110 to the central axis O of the eccentric shaft 110 are different. The distances from different positions of the moving member 132 along the radial direction of the eccentric shaft 110 to the central axis O of the eccentric shaft 110 are different.

[0084] The movable member 132 includes an outer peripheral surface 111, which includes a first outer peripheral portion 112 and a second outer peripheral portion 113. The first outer peripheral portion 112 and the second outer peripheral portion 113 are spaced apart. The first outer peripheral portion 112 and the second outer peripheral portion 113 are arranged opposite each other along the radial direction of the eccentric shaft 110. The distance from the first outer peripheral portion 112 to the central axis of the movable member 132 is different from the distance from the second outer peripheral portion 113 to the central axis of the movable member 132. The distance from the first outer peripheral portion 112 along the radial direction of the eccentric shaft 110 to the central axis O of the eccentric shaft 110 is greater than the distance from the second outer peripheral portion 113 along the radial direction of the eccentric shaft 110 to the central axis O of the eccentric shaft 110. The centerline M of the rotating assembly 130 is spaced apart from the central axis O of the eccentric shaft 110.

[0085] like Figure 2 As shown, the eccentricity between the centerline M of the rotating assembly 130 and the centerline O of the eccentric shaft 110 is e. Rmax is the large radius of rotation of the eccentric shaft 110, and Rmin is the small radius of rotation of the eccentric shaft 110. Rmax = Rmin + e.

[0086] The rotation of the eccentric shaft 110 can drive the rotating component 131 to rotate, and the eccentric shaft 110 can drive the rotating component 131 to rotate along an elliptical motion trajectory. The rolling component 133 can convert the rotational motion of the rotating component 131 into the linear motion of the moving component 132, so that the moving component 132 moves linearly along the radial direction of the eccentric shaft 110.

[0087] The first plunger 141 and the second plunger 142 are arranged opposite each other along the radial direction of the eccentric shaft 110. Rotation of the eccentric shaft 110 drives the first plunger 141 to reciprocate. The larger portion abuts against the first plunger 141. The first plunger 141 is in contact with the first outer peripheral portion 112. The end plane of the first plunger 141 is in contact with the eccentric shaft 110. The first plunger 141 moves linearly along the radial direction of the eccentric shaft 110 with the moving member 132.

[0088] The rotation of the eccentric shaft 110 can also drive the second plunger 142 to reciprocate. The larger portion also abuts against the second plunger 142. The second plunger 142 is in contact with the second outer peripheral portion 113. The end plane of the second plunger 142 is in contact with the eccentric shaft 110. The second plunger 142 moves linearly along the radial direction of the eccentric shaft 110 with the moving member 132.

[0089] To ensure synchronous movement of the first plunger 141 and the second plunger 142, the plunger return device 100 further includes a connecting member 150, which connects the first plunger 141 and the second plunger 142. The first plunger 141 and the second plunger 142 move in the same direction and at the same speed. This ensures the synchronicity of the movement of the first plunger 141 and the second plunger 142.

[0090] According to the plunger return device 100 of this application, the plunger return device 100 includes an eccentric shaft 110, a rotating assembly 130, a first plunger 141, a second plunger 142, and a connecting member 150. The rotating assembly 130 includes a rotating member 131, a moving member 132, and a rolling member 133. The rolling member 133 is located between the rotating member 131 and the moving member 132. The rotating member 131 is connected to the eccentric shaft 110. The moving member 132 includes an outer peripheral surface, and the outer peripheral surface 111 of the moving member 132 includes a first outer peripheral portion. 112 and 113, the first plunger 141 and the second plunger 142 are arranged opposite each other in the radial direction of the eccentric shaft 110. The first plunger 141 is in contact with the first outer peripheral portion 112, and the second plunger 142 is in contact with the second outer peripheral portion 113. The connecting member 150 connects the first plunger 141 and the second plunger 142. The distance between the first outer peripheral portion 112 and the central axis O of the eccentric shaft 110 in the radial direction is different from the distance between the second outer peripheral portion 113 and the central axis O of the eccentric shaft 110 in the radial direction. In this way, the structure is simple and the manufacturing cost is low. It transforms sliding friction into rolling friction, reducing the wear on the first plunger 141 and the second plunger 142, avoiding abnormal wear and low reliability and lifespan. The connecting member 150 rigidly connects the first plunger 141 and the second plunger 142 together to achieve synchronous movement, avoiding jamming or failure that would cause the first plunger 141 and / or the second plunger 142 to be unable to return to their original position or not to return to their original position. This greatly improves the reliability and lifespan of the plunger return device 100.

[0091] The rotation of the eccentric shaft 110 can drive the rotating assembly 130 to move linearly between the first position and the second position, so that the first plunger 141 and the second plunger 142 can both move linearly along the radial direction of the eccentric shaft 110.

[0092] For example, when the eccentric shaft 110 rotates from 0° to 180° around its central axis O, the rotating member 131 in the first position rotates around the central axis O of the eccentric shaft 110. The first plunger 141 moves away from the second plunger 142 along the radial direction of the eccentric shaft 110, and the second plunger 142 moves towards the first plunger 141 along the radial direction of the eccentric shaft 110.

[0093] When the eccentric shaft 110 rotates from 180° to 360° around its central axis O, the rotating member 131 in the second position rotates. The first plunger 141 moves toward the second plunger 142 along the radial direction of the eccentric shaft 110, and the second plunger 142 moves away from the first plunger 141 along the radial direction of the eccentric shaft 110.

[0094] The centerline M of the rotating assembly 130 in the first position is spaced apart from the central axis O of the eccentric shaft 110 along the radial direction of the eccentric shaft 110. The distance between the first outer peripheral portion 112 in the first position and the central axis O of the eccentric shaft 110 along the radial direction of the eccentric shaft 110 is different from the distance between the second outer peripheral portion 113 in the first position and the central axis O of the eccentric shaft 110 along the radial direction of the eccentric shaft 110. Therefore, the first outer peripheral portion 112 in the first position can move linearly to the second position along the radial direction of the eccentric shaft 110, and the second outer peripheral portion 113 in the first position can move linearly to the second position along the radial direction of the eccentric shaft 110.

[0095] The centerline M of the rotating assembly 130 in the second position is spaced apart from the central axis O of the eccentric shaft 110 along the radial direction of the eccentric shaft 110. The distance between the first outer peripheral portion 112 in the second position and the central axis O of the eccentric shaft 110 along the radial direction is different from the distance between the second outer peripheral portion 113 in the second position and the central axis O of the eccentric shaft 110 along the radial direction of the eccentric shaft 110. Therefore, the first outer peripheral portion 112 in the second position can move linearly to the first position along the radial direction of the eccentric shaft 110, and the second outer peripheral portion 113 in the second position can move linearly to the first position along the radial direction of the eccentric shaft 110.

[0096] The first outer peripheral portion 112 can reciprocate linearly between a first position and a second position along the radial direction of the eccentric shaft 110. Thus, the first plunger 141 can reciprocate linearly along the radial direction of the eccentric shaft 110. The second outer peripheral portion 113 can reciprocate linearly between a first position and a second position along the radial direction of the eccentric shaft 110. Thus, the second plunger 142 can reciprocate linearly along the radial direction of the eccentric shaft 110.

[0097] There is also a balance position between the first position and the second position. The centerline M of the rotating assembly 130 in the balance position is on the same horizontal plane as the central axis O of the eccentric shaft 110. Thus, the distance between the first plunger 141 and the central axis O of the eccentric shaft 110 along the radial direction is equal to the distance between the second plunger 142 and the central axis O of the eccentric shaft 110 along the radial direction. The first plunger 141 and the second plunger 142 are held in the balance position relative to each other.

[0098] To ensure the linear movement of the first plunger 141, we now return to... Figure 1 The plunger return device 100 also includes a first plunger cylinder 143, within which a first plunger 141 is located. The first plunger 141 and the first plunger cylinder 143 are coaxially arranged. The axial directions of both the first plunger 141 and the first plunger cylinder 143 are parallel to the radial direction of the eccentric shaft 110. The first plunger cylinder 143 guides the first plunger 141. The first plunger 141 and the first plunger cylinder 143 are fitted with a cylindrical surface clearance, the specific clearance value varying depending on the diameter of the first plunger 141. The first plunger 141 reciprocates linearly within the first plunger cylinder 143 along the radial direction of the eccentric shaft 110. The first plunger cylinder 143 limits the movement of the first plunger 141 along its radial direction, preventing the first plunger 141 from deviating during movement.

[0099] To ensure the linear movement of the second plunger 142, the plunger return device 100 further includes a second plunger cylinder 144, within which the second plunger 142 is located. The second plunger 142 and the second plunger cylinder 144 are coaxially arranged. The axial directions of both the second plunger 142 and the second plunger cylinder 144 are parallel to the radial direction of the eccentric shaft 110. The second plunger cylinder 144 serves as a guide for the second plunger 142. The second plunger 142 and the second plunger cylinder 144 are fitted with a cylindrical surface clearance, the specific clearance value varying depending on the diameter of the second plunger 142. The second plunger 142 reciprocates linearly within the second plunger cylinder 144 along the radial direction of the eccentric shaft 110. The second plunger cylinder 144 limits the movement of the second plunger 142 along its radial direction, preventing deviation during movement.

[0100] Liquid is contained in the first plunger cylinder 143. Liquid is contained in the second plunger cylinder 144. The first plunger 141 moves radially away from the second plunger 142 along the eccentric shaft 110, compressing the liquid in the first plunger cylinder 143 and discharging it. Simultaneously, the second plunger 142 moves radially toward the first plunger 141 along the eccentric shaft 110, expanding the volume of the second plunger cylinder 144 and drawing liquid into it.

[0101] The first plunger 141 moves radially toward the second plunger 142 along the eccentric shaft 110, expanding the volume of the first plunger cylinder 143 and drawing liquid into it. Simultaneously, the second plunger 142 moves radially away from the first plunger 141 along the eccentric shaft 110, compressing the liquid in the second plunger cylinder 144 and discharging it.

[0102] When the center line M of the rotating assembly 130 is above the center axis O of the eccentric shaft 110, that is, when e is positive, both the first plunger 141 and the second plunger 142 move upward.

[0103] The first plunger 141 retracts into the first plunger cylinder 143, and the first plunger 141 is in the oil discharge stage.

[0104] The second plunger 142 extends out of the second plunger cylinder 144, and the second plunger 142 is in the oil suction stage.

[0105] When the center line M of the rotating assembly 130 is below the center axis O of the eccentric shaft 110, that is, when e is negative, both the first plunger 141 and the second plunger 142 move downward.

[0106] The first plunger 141 extends out of the first plunger cylinder 143, and the first plunger 141 is in the oil suction stage.

[0107] The second plunger 142 retracts into the second plunger cylinder 144, and the second plunger 142 is in the oil discharge stage.

[0108] When the center plane of the rotating assembly 130 is located in the plane containing the central axis O of the eccentric shaft 110, both the first plunger 141 and the second plunger 142 are in the centered position. Neither the first plunger 141 nor the second plunger 142 draws in or discharges oil. The eccentric shaft 110 rotates circumferentially, driving the first plunger 141 and the second plunger 142 to move periodically, thereby achieving pressurized oil supply.

[0109] To ensure the synchronization of the movement of the first plunger 141 and the second plunger 142, such as Figure 4As shown, the connecting member 150 is constructed as a retaining ring, and both the first plunger 141 and the second plunger 142 are provided with annular grooves. The annular groove of the first plunger 141 is recessed inward from the outer peripheral surface of the first plunger 141. The neck diameter of the annular groove of the first plunger 141 is smaller than the working surface diameter of the first plunger 141. In this embodiment, the "working surface diameter of the first plunger 141" refers to the diameter of the outer peripheral surface of the first plunger 141. The width of the annular groove of the first plunger 141 is slightly larger than the thickness δ of the connecting member 150. The annular groove of the second plunger 142 is recessed inward from the outer peripheral surface of the second plunger 142. The neck diameter of the annular groove of the second plunger 142 is smaller than the working surface diameter of the second plunger 142. In this embodiment, the "working surface diameter of the second plunger 142" refers to the diameter of the outer peripheral surface of the second plunger 142. The width of the annular groove of the second plunger 142 is slightly larger than the thickness δ of the connecting member 150.

[0110] The connecting member 150 is constructed as a semi-circular shape with uniform wall thickness. The connecting member 150 is made of spring steel. A retaining ring and an annular groove engage. In this way, the connecting member 150 connects the first plunger 141 and the second plunger 142 together, allowing the first plunger 141 and the second plunger 142 to move synchronously. The annular groove of the first plunger 141 is used to support and mount one end of the connecting member 150. The annular groove of the second plunger 142 is used to support and mount the other end of the connecting member 150.

[0111] The connecting member 150 is constructed as a semi-annular structure. The connecting member 150 includes a first free end 151, a second free end 152, and an arc-shaped segment 153, with the first free end 151 and the second free end 152 connected via the arc-shaped segment 153. The first free end 151 engages with the first plunger 141. The first free end 151 engages with the annular groove of the first plunger 141. Thus, the first free end 151 is detachably connected to the first plunger 141. The second free end 152 engages with the second plunger 142. The second free end 152 engages with the annular groove of the second plunger 142. Thus, the second free end 152 is detachably connected to the second plunger 142.

[0112] The first free end 151 includes a first slot 154, the opening of which faces the first plunger 141, so that the first slot 154 engages with the first plunger 141. The second free end 152 includes a second slot 155, the opening of which faces the second plunger 142, so that the second slot 155 engages with the second plunger 142.

[0113] One of the first slot 154 and the second slot 155 includes a first slot wall, and the two first slot walls are parallel. This facilitates assembly and disassembly. The other of the first slot 154 and the second slot 155 includes a second slot wall. Optionally, the other of the first slot 154 and the second slot 155 also includes a second slot bottom, which is connected to the second slot wall. The second slot wall has an inwardly protruding protrusion. This allows the two second slot walls to be more securely connected to the second plunger 142. When the first slot 154 is separated from the first plunger 141, the second slot 155 remains engaged with the second plunger 142.

[0114] In this embodiment, such as Figure 5 As shown, the first slot 154 includes a first slot wall 156, and the two first slot walls 156 of the first slot 154 are parallel. The first slot 154 also includes a first slot bottom 159, which is semi-circular in shape. Figure 7 As shown, the diameter of the first groove bottom 159 is 'a', and the first slot 154 extends through the first free end 151 of the connecting member 150 along its thickness direction. The first groove wall 156 and the first groove bottom 159 are tangent. The first slot 154 also includes a first opening 163, the dimension of which along the width direction of the connecting member 150 is larger than the dimension between the two first groove walls 156. The first opening 163 and the first groove wall 156 are rounded. The included angle of the first opening 163 along the width direction of the connecting member 150 is r1. Thus, the first groove bottom 159 and the annular groove of the first plunger 141 are in clearance fit.

[0115] like Figure 6 As shown, the second slot 155 includes second slot walls 157, each of which has a protrusion 158. The protrusions 158 of the two second slot walls 157 protrude toward each other. The second slot 155 also includes a second slot bottom 160, which is semi-circular. The diameter of the second slot bottom 160 is b, and the second slot 155 extends through the second free end 152 of the connecting member 150 along its thickness direction. The second slot 155 also includes a second opening 164, the dimension of which along the width direction of the connecting member 150 is larger than the dimension between the two second slot walls 157. The second opening 164 and the second slot walls 157 are rounded.

[0116] The second groove wall 157 includes a first inclined segment 161 and a second inclined segment 162, which are connected. The included angle between the first inclined segment 161 and the second inclined segment 162 is an obtuse angle. The first inclined segment 161 extends inward from the bottom of the second groove 160. In this embodiment, "the first inclined segment 161 extends inward" means that the first inclined segment 161 of one second groove wall 157 extends in an inclined direction toward the other second groove wall 157. The second inclined end extends outward from the first inclined segment 161. In this embodiment, "the second inclined segment 162 extends outward" means that the second inclined segment 162 of one second groove wall 157 extends in an inclined direction away from the other second groove wall 157. Thus, the distance between the connection points of the first inclined segments 161 and the second inclined segments 162 of the two second groove walls 157 is small, which helps the second slot 155 to engage with the second plunger 142.

[0117] like Figure 8 As shown, the included angle of the second opening 164 along the width direction of the connecting member 150 is r1. The second groove wall 157 and the second groove bottom 160 are inclinedly connected. A narrowing is formed between the two second groove walls 157. The included angle between the two first inclined sections 161 is r2. In this way, the second groove bottom 160 and the annular groove of the second plunger 142 are transitionally fitted, ensuring that the connecting member 150 will not fall off after it is locked into the second plunger 142.

[0118] In one optional embodiment, the angle of r1 is 30° to 40°, and the angle of r2 is 20° to 30°. The second groove bottom 160 is transitionally fitted with the second plunger 142 with a clearance of 0.002 to 0.015 mm to ensure that the second free end 152 will not fall off after being locked with the second plunger 142. The first groove bottom 159 is clearance-fitted with the first plunger 141 with a clearance of 0.03 to 0.06 mm to avoid poor coaxiality between the first free end 151 and the second free end 152 or between the first plunger 141 and the second plunger 142, which could lead to assembly failure. Furthermore, it enables self-adjustment when the first plunger 141 and the second plunger 142 are not coaxial. The first free end 151 and the second free end 152 are guaranteed to be coaxial, and the degree of freedom between the first free end 151 and the second free end 152 is 0.005 to 0.01.

[0119] Of course, in embodiments not shown, the first slot 154 includes a second slot wall 157, and the second slot wall 157 of the first slot 154 has an inwardly protruding protrusion 158. The second slot 155 includes a first slot wall 156, and the two first slot walls 156 of the second slot 155 are parallel.

[0120] Therefore, the first free end 151 and the first plunger 141 are fitted with a clearance to avoid poor coaxiality between the first free end 151 and the second free end 152 of the connecting member 150 or poor coaxiality between the first plunger 141 and the second plunger 142, which would prevent assembly failure. Furthermore, self-adjustment can be achieved when the first plunger 141 and the second plunger 142 are not coaxial. The first groove bottom 159 and the second groove bottom 160 ensure coaxiality.

[0121] According to the plunger return device 100 of this application, the existing high-speed rotating cylindrical surface and plunger end face undergo tangential sliding friction, avoiding abnormal wear and low reliability and lifespan. Instead, a thrust bearing is used to convert sliding friction into rolling friction. The end faces of the moving component 132 and the first plunger 141 are relatively stationary, and the end faces of the moving component 132 and the second plunger 142 are relatively stationary, improving complex stress conditions and avoiding abnormal friction and wear on the end faces of the first plunger 141 and the second plunger 142. According to the plunger return device 100 of this application, the existing spring 172 for plunger return is eliminated. Instead, a connecting component 150 is used to rigidly connect the first plunger 141 and the second plunger 142 together, achieving synchronous movement. This avoids jamming or failure that could cause the first plunger 141 and / or the second plunger 142 to fail to return to their original positions, greatly improving reliability and lifespan. According to the plunger return device 100 of this application, the linear motion trajectory of the first plunger 141 is perpendicular to the central axis O of the eccentric shaft 110, and the linear motion trajectory of the second plunger 142 is perpendicular to the central axis O of the eccentric shaft 110.

[0122] like Figure 9 As shown, this application also provides a plunger pump 200, which includes the aforementioned plunger return device 100. (In conjunction with...) Figure 1 As shown, the plunger pump 200 further includes a first chamber 201, in which a first plunger 141 is located. Preferably, the first plunger cylinder 143 includes the first chamber 201, and the first plunger 141 is located in the first chamber 201 of the first plunger cylinder 143. The first plunger 141 is capable of compressing or discharging liquid in the first chamber 201.

[0123] The plunger pump 200 further includes a second chamber 202, in which a second plunger 142 is located. Preferably, the second plunger cylinder 144 includes a second chamber 202, in which the second plunger 142 is located. The second plunger 142 is capable of compressing or discharging liquid in the second chamber 202.

[0124] According to the plunger pump 200 of this application, the plunger pump 200 includes the plunger return device 100 described above. The plunger pump 200 further includes a first chamber 201 and a second chamber 202. The first plunger 141 is located in the first chamber 201, and the second plunger 142 is located in the second chamber 202. The plunger return device 100 includes an eccentric shaft 110, a rotating assembly 130, a first plunger 141, a second plunger 142, and a connecting member 150. The rotating assembly 130 includes a rotating member 131, a moving member 132, and a rolling member 133. The rolling member 133 is located between the rotating member 131 and the moving member 132. The rotating member 131... Connected to the eccentric shaft 110, the moving member 132 includes an outer peripheral surface. The outer peripheral surface 111 of the moving member 132 includes a first outer peripheral portion 112 and a second outer peripheral portion 113. The first plunger 141 and the second plunger 142 are arranged opposite to each other along the radial direction of the eccentric shaft 110. The first plunger 141 is in contact with the first outer peripheral portion 112, and the second plunger 142 is in contact with the second outer peripheral portion 113. The connecting member 150 connects the first plunger 141 and the second plunger 142. The distance between the first outer peripheral portion 112 and the central axis O of the eccentric shaft 110 along the radial direction is different from the distance between the second outer peripheral portion 113 and the central axis O of the eccentric shaft 110 along the radial direction. In this way, the structure is simple and the manufacturing cost is low. It transforms sliding friction into rolling friction, reducing the wear on the first plunger 141 and the second plunger 142, avoiding abnormal wear and low reliability and lifespan. The connecting member 150 rigidly connects the first plunger 141 and the second plunger 142 together to achieve synchronous movement, avoiding jamming or failure that would cause the first plunger 141 and / or the second plunger 142 to be unable to return to their original position or not to return to their original position. This greatly improves the reliability and lifespan of the plunger return device 100.

[0125] The plunger pump 200 is a radial plunger pump. The number of the first plunger 141 and the second plunger 142 of the plunger return device 100 can be set as needed, that is, the number of the first plunger 141 and the second plunger 142 can be any number between 1 and 11.

[0126] The eccentric shaft 110 rotates, allowing the first plunger 141 to move toward or away from the second plunger 142. For example... Figure 9 As shown, the plunger pump 200 also includes a first port 203, which communicates with the first chamber 201. The first port 203 and the eccentric shaft 110 are located on opposite sides of the first chamber 201 along the radial direction of the eccentric shaft 110. The first plunger 141 moves toward the second plunger 142 to draw liquid from the first port 203 into the first chamber 201, thereby achieving oil suction by the first plunger 141. The volume of the first chamber 201 is expanded, and liquid from the first port 203 is drawn into the first chamber 201.

[0127] The second plunger 142 moves in the same direction as the first plunger 141. When the first plunger 141 moves toward the second plunger 142, the second plunger 142 moves away from the first plunger 141. The plunger pump 200 also includes a second port 204, which communicates with the second chamber 202. The second port 204 and the eccentric shaft 110 are located on opposite sides of the second chamber 202 along the radial direction of the eccentric shaft 110. The second plunger 142 moves away from the first plunger 141 to discharge liquid from the second chamber 202 through the second port 204, thereby achieving oil discharge from the second plunger 142. As the second plunger 142 moves away from the first plunger 141, the volume of the second chamber 202 is compressed, and the liquid in the second chamber 202 is discharged through the second port 204.

[0128] Similarly, the first plunger 141 moves away from the second plunger 142 to discharge liquid from the first chamber 201 through the first port 203, thereby achieving oil discharge from the first plunger 141. The volume of the first chamber 201 is compressed, and the liquid in the first chamber 201 is discharged through the first port 203. The second plunger 142 moves toward the first plunger 141 to draw liquid from the second port 204 into the second chamber 202, thereby achieving oil suction from the second plunger 142. The second plunger 142 moves toward the first plunger 141, the volume of the second chamber 202 is expanded, and liquid from the second port 204 is drawn into the second chamber 202. In this way, the periodic oil suction and discharge process of the first plunger 141 and the second plunger 142 can be realized.

[0129] Furthermore, the plunger pump 200 also includes a low-pressure inlet, with both the first port 203 and the second port 204 connected to it. When the first plunger 141 moves toward the second plunger 142, liquid from the low-pressure inlet can enter the first chamber 201 through the first port 203. When the second plunger 142 moves toward the first plunger 141, liquid from the low-pressure inlet can enter the second chamber 202 through the second port 204.

[0130] To prevent oil leakage from the plunger pump 200 and improve the lubrication conditions of the friction pairs, such as Figure 10 As shown, the plunger pump 200 also includes a return oil chamber 205, which is used to recover liquid leaked from various components of the plunger pump 200. A rotating assembly 130 is disposed in the return oil chamber 205. This allows liquid at the rotating assembly 130 to enter the return oil chamber 205.

[0131] The return oil chamber 205 is connected to the first chamber 201. This allows leaked liquid in the first chamber 201 to flow into the return oil chamber 205 for recovery. The return oil chamber 205 is also connected to the second chamber 202. This allows leaked liquid in the second chamber 202 to flow into the return oil chamber 205 for recovery. The return oil chamber 205 can also be connected to a low-pressure inlet. Liquid in the return oil chamber 205 can flow back to the low-pressure inlet, improving energy efficiency.

[0132] Now return Figure 9 The plunger pump 200 also includes a flow distribution control unit and a transmission sealing unit. The flow distribution control unit includes a first check valve 211, a second check valve 212, a third check valve 213, and a fourth check valve 214. The first check valve 211 and the third check valve 213 are connected in series. The second check valve 212 and the fourth check valve 214 are connected in series. The low-pressure inlet is connected to the inlets of the third check valve 213 and the fourth check valve 214 through a low-pressure oil circuit. The low-pressure oil circuit is the oil circuit for the plunger to draw in during operation. The high-pressure outlet is connected to the outlets of the first check valve 211 and the second check valve 212 through a high-pressure oil circuit. The high-pressure oil circuit is the high-pressure oil circuit for the plunger pump 200 to discharge during operation. The first plunger 141 is connected to the first check valve 211 and the third check valve 213 through a first oil circuit 221. The first oil circuit 221 is the oil circuit for the first plunger 141 to draw in or discharge during operation. The second plunger 142 is connected to the second check valve 212 and the fourth check valve 214 via a second oil passage 222. The second oil passage 222 is the passage for oil to be drawn in or discharged when the second plunger 142 is working. The return oil is connected to the low-pressure inlet via a return oil passage 223. The return oil passage 223 is the passage for internal leakage discharge when the first plunger 141 and the second plunger 142 are working.

[0133] like Figure 10 and Figure 11 As shown, the transmission sealing unit includes a pump base 206, an adapter block 207, an oil seal 208, and a retaining ring 209. The retaining ring 209 is located outside the oil seal 208 to prevent the adapter block 207 from moving. The pump base 206 is connected to the main unit via a plate-type connection and is fixed by screws. The first check valve 211, the second check valve 212, the third check valve 213, and the fourth check valve 214 are integrated into the pump base 206. The first oil passage 221, the second oil passage 222, and the return oil passage 223 are designed and laid out in the pump base 206. The pump base 206 is integrally printed and then machined for related installation interfaces. The inlet / outlet can be set on the same side as the flange and the eccentric shaft 110 (such as the power output shaft of the motor) or on different sides, depending on actual needs. The eccentric shaft 110 can rotate in both directions (left-hand or right-hand), while the inlet and outlet remain unchanged.

[0134] During assembly, the first plunger 141 is inserted into the first plunger cylinder 143, and the second plunger 142 is inserted into the second plunger cylinder 144. Then, the first plunger cylinder 143 is inserted downwards into one corresponding mounting hole of the pump base 206, and the second plunger cylinder 144 is inserted upwards into the other corresponding mounting hole of the pump base 206. Next, the connecting component 150 is installed to secure the first plunger 141 and the second plunger 142. The rotating assembly 130 is pressed into the eccentric shaft 110 from the left end, and then the bearings are pressed into the eccentric shaft 110 from both the left and right ends, and then inserted into the mounting holes of the pump base 206. The oil seal 208 is pressed into the adapter block 207 and then inserted into the corresponding mounting hole of the pump base 206, with the connection secured by screws. The other end of the adapter block 207 has a flange mounting hole and a connecting screw mounting hole for connecting and installing the main unit (or motor).

[0135] The return oil passage 223 connects the pump chamber to the low-pressure inlet. This allows the bearings, rotating components 130, and oil seal 208 to operate in an oil-lubricated environment, reducing operating noise, improving lubrication conditions, dissipating heat, and significantly improving the performance, lifespan, and reliability of the bearings and oil seal 208. Oil leakage between the first plunger 141 and the first plunger cylinder 143 can also be discharged into the low-pressure inlet via the return oil passage 223. Similarly, oil leakage between the second plunger 142 and the second plunger cylinder 144 can also be discharged into the low-pressure inlet via the return oil passage 223.

[0136] The bearing and rotating assembly 130 are tightly fitted with the eccentric shaft 110, and the oil seal 208 is tightly fitted with the adapter block 207. The oil seal 208 and the eccentric shaft 110 form a dynamic seal to ensure that the return hydraulic pressure does not leak. The retaining ring 209 is used to prevent the oil seal 208 from loosening. The return oil passage 223 connects the return oil to the low-pressure inlet. A "D"-shaped hole can be provided inside one end of the eccentric shaft 110 according to actual needs for connecting and transmitting torque and speed input. Of course, other forms of connection structures can also be provided at one end of the eccentric shaft 110, and this embodiment does not limit this.

[0137] During operation, when the motor's set speed is input, the eccentric shaft 110 rotates synchronously with the motor input shaft at the same speed. Because there is an eccentricity e between the centerline M of the rotating assembly 130 and the centerline O of the eccentric shaft 110, when the centerline M of the rotating assembly 130 is above the centerline O of the eccentric shaft 110, the first plunger 141 moves upward under the thrust of the rotating assembly 130, discharging oil. Simultaneously, the first plunger 141 applies an upward pulling force to the second plunger 142 through the connecting member 150, and the second plunger 142 moves upward synchronously with the first plunger 141, drawing in oil.

[0138] When the centerline M of the rotating assembly 130 is below the centerline O of the eccentric shaft 110, the second plunger 142 moves downward under the thrust of the rotating assembly 130 to discharge oil. At the same time, the second plunger 142 applies a downward pulling force to the first plunger 141 through the connecting member 150, and the first plunger 141 and the second plunger 142 move downward synchronously, with the first plunger 141 drawing in oil.

[0139] Each time the eccentric shaft 110 rotates, the first plunger 141 and the second plunger 142 each complete one oil suction and discharge cycle, which can continuously complete the oil suction and discharge actions. When the center line M of the rotating assembly 130 is on the horizontal plane of the center axis O of the eccentric shaft 110, the first plunger 141 and the second plunger 142 are in the center position and do not suction or discharge oil.

[0140] like Figure 12 As shown, this application also provides a plunger return device 100, which includes a rocker arm 170, a rotating assembly 130, a first plunger 141, and a second plunger 142. The rocker arm 170 is connected to the rotating assembly 130, and movement of the rotating assembly 130 can drive movement of the rocker arm 170. The rotating assembly 130 is located between the first plunger 141 and the second plunger 142.

[0141] The rotating assembly 130 includes a rotating member 131, a moving member 132, and a rolling member 133, all of which are coaxially arranged. The rotating assembly 130 can be configured as a thrust bearing. Both the rotating member 131 and the moving member 132 can be configured as annular structures. The rolling member 133 is configured as a spherical structure. The rolling member 133 is located between the rotating member 131 and the moving member 132. The rotating assembly 130 includes multiple rolling members 133, which are located between the rotating member 131 and the moving member 132.

[0142] Rotating member 131 is connected to rocker arm 170. Rocker arm 170 is part of a swashplate. Rocker arm 170 includes a large portion and a small portion, which are connected. The dimension of the large portion in the radial direction along the connecting shaft is larger than the dimension of the small portion. The connecting shaft is connected to the large portion. Rocker arm 170 is capable of rotating about the central axis of the connecting shaft. The small portion is located to the side of the large portion in the radial direction along the connecting shaft.

[0143] The rotating assembly 130 is connected to the smaller portion. The rocker arm 170 also includes an end shaft 171, which is connected to the smaller portion. The end shaft 171 protrudes from the smaller portion along the axial direction of the connecting shaft. The rotating member 131 can be sleeved on the outside of the end shaft 171. The rotating member 131 and the end shaft 171 can be engaged together. Rotation of the rotating member 131 can drive the end shaft 171 to rotate, thereby driving the smaller portion to rotate, and further driving the larger portion to rotate about the central axis of the connecting shaft.

[0144] The movable member 132 includes an outer peripheral surface, and the outer peripheral surface 111 of the movable member 132 includes a first outer peripheral portion 112 and a second outer peripheral portion 113. The first outer peripheral portion 112 and the second outer peripheral portion 113 are spaced apart. The first outer peripheral portion 112 and the second outer peripheral portion 113 are arranged opposite to each other along the radial direction of the end shaft 171.

[0145] The end shaft 171 is an eccentric shaft. The first plunger 141 and the second plunger 142 are arranged opposite each other along the radial direction of the end shaft 171. The first plunger 141 is in contact with the first outer peripheral portion 112. The first plunger 141 abuts against the first outer peripheral portion 112 of the moving member 132. The first plunger 141 is capable of linear movement along the radial direction of the end shaft 171. The second plunger 142 is in contact with the second outer peripheral portion 113. The second plunger 142 abuts against the second outer peripheral portion 113 of the moving member 132. The second plunger 142 is capable of linear movement along the radial direction of the end shaft 171. The first plunger 141 and the second plunger 142 move in the same direction. The first plunger 141 moves along the radial direction of the end shaft 171 to push the moving member 132 to move, thereby pushing the second plunger 142 to move. The rolling member 133 can convert the linear motion of the moving member 132 into the rotational motion of the rotating member 131.

[0146] To ensure the linear movement of the first plunger 141, the plunger return device 100 further includes a first plunger cylinder 143, within which the first plunger 141 is located. The first plunger 141 and the first plunger cylinder 143 are coaxially arranged. The axial directions of both the first plunger 141 and the first plunger cylinder 143 are parallel to the radial direction of the end shaft 171. The first plunger cylinder 143 serves as a guide for the first plunger 141. The first plunger 141 reciprocates linearly within the first plunger cylinder 143 along the radial direction of the end shaft 171. The first plunger cylinder 143 limits the movement of the first plunger 141 along the radial direction of the first plunger cylinder 143, preventing the first plunger 141 from deviating during movement.

[0147] To ensure the linear movement of the second plunger 142, the plunger return device 100 further includes a second plunger cylinder 144, within which the second plunger 142 is located. The second plunger 142 and the second plunger cylinder 144 are coaxially arranged. The axial directions of both the second plunger 142 and the second plunger cylinder 144 are parallel to the radial direction of the end shaft 171. The second plunger cylinder 144 serves as a guide for the second plunger 142. The second plunger 142 reciprocates linearly within the second plunger cylinder 144 along the radial direction of the end shaft 171. The second plunger cylinder 144 also limits the movement of the second plunger 142 along its radial direction, preventing it from deviating during movement.

[0148] Liquid is contained in the first plunger cylinder 143. A spring 172 is contained in the second plunger 142. Pressure P in the first plunger cylinder 143 is applied to the first plunger 141, causing the first plunger 141 to move radially toward the second plunger 142 along the end shaft 171. The moving member 131 moves toward the second plunger 142, thereby pushing the second plunger 142 to move, thus compressing the spring 172. The movement of the moving member 131 causes the rotating member 133 to rotate, which in turn causes the end shaft 171 to rotate. The rotation of the end shaft 171 causes the smaller portion to rotate, which in turn causes the larger portion to rotate, thereby causing the rocker arm 170 to swing.

[0149] When the liquid does not apply pressure P to the first plunger 141, the spring 172 applies an elastic force to the second plunger 142. The second plunger 142 moves radially toward the first plunger 141 along the end shaft 171, while the rotating member 131 moves in the opposite direction toward the first plunger 141, thereby pushing the first plunger 141 to move. This causes the first plunger 141 to compress the liquid, resulting in the liquid being discharged. The reverse rotation of the end shaft 171 causes the smaller part to rotate in the opposite direction, which in turn causes the larger part to rotate in the opposite direction, thereby causing the rocker arm 170 to swing in the opposite direction.

[0150] According to the plunger return device 100 of this application, the plunger return device 100 includes a rocker arm 170, a rotating assembly 130, a first plunger 141 and a second plunger 142. The rotating assembly 130 includes a rotating member 131, a moving member 132 and a rolling member 133. The rolling member 133 is located between the rotating member 131 and the moving member 132. The rotating member 131 is connected to the rocker arm 170. The first plunger 141 and the second plunger 142 are arranged opposite to each other. Both the first plunger 141 and the second plunger 142 are in contact with the outer peripheral surface 111 of the moving member 132. The first plunger 141 can move towards the second plunger 142 to push both the moving member 132 and the second plunger 142 to move, so that the rotating member 131 drives the rocker arm 170 to swing. In this way, the structure is simple, the manufacturing cost is low, the wear on the first plunger 141 and the second plunger 142 is reduced, the problems of abnormal wear and low reliability and lifespan are avoided, and the reliability and lifespan of the plunger return device 100 are greatly improved.

[0151] Thus, the plunger return device 100 can also be used in applications where the rocker arm 170 moves (non-rotational motion). Under pressure P, the first plunger 141 generates a leftward force acting on the rotating assembly 130. When pressure P exceeds the elastic force of the spring 172, the moving member 132 pushes the second plunger 142 to the left. Since the connecting shaft and the smaller portion are rigidly connected or integrally manufactured, the rotating member 131 transmits pressure P to the rocker arm 170 via the connecting shaft, causing the larger portion to swing left around the center N, changing the swashplate angle (reducing it).

[0152] Conversely, when the first plunger 141 is without pressure P, under the action of the elastic force of the spring 172, the second plunger 142, the moving member 132 and the first plunger 141 are simultaneously subjected to the elastic force and move to the right. The large part of the rocker arm 170 swings to the right around the center N, changing the swashplate angle (increasing it).

[0153] During the above process, the moving component 132 does not have sliding friction with the first plunger 141 and the second plunger 142, which avoids friction and wear, greatly improves the stress conditions, avoids friction and wear caused by sliding friction, and significantly improves the reliability and life of the plunger pump 200.

[0154] The plunger return device 100 and plunger pump 200 according to this application can be applied in the aerospace and civil engineering fields. The plunger return device 100 of this application eliminates the tangential sliding friction between the high-speed rotating cylindrical surface and the plunger end face in existing structures, avoiding abnormal wear and low reliability and lifespan. It uses a thrust bearing to convert sliding friction into rolling friction. The plunger return device 100 of this application eliminates the use of a spring 172 for plunger return in existing structures. Instead, it uses a connecting member 150 to rigidly connect the first plunger 141 and the second plunger 142, achieving synchronous movement. This avoids the problem of the first plunger 141 and the second plunger 142 failing to return to their original positions due to spring 172 jamming or failure, greatly improving the reliability and lifespan of the plunger pump 200. Compared to the plunger pump 200, the plunger return device 100 of this application has a simpler structure, lower manufacturing cost, and avoids special processes such as plunger tapering and bimetallic machining.

[0155] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for descriptive purposes only and is not intended to limit the scope of this application. Terms such as “part” or “component” appearing herein can refer to a single part or a combination of multiple parts. Terms such as “installation” or “installation” appearing herein can refer to one component being directly attached to another component or one component being attached to another component via an intermediary. A feature described in one embodiment herein may be applied, alone or in combination with other features, to another embodiment, unless that feature is not applicable in that other embodiment or is otherwise stated.

[0156] This application has been described through the above embodiments; however, it should be understood that the above embodiments are for illustrative purposes only and are not intended to limit this application to the described embodiments. Furthermore, those skilled in the art will understand that this application is not limited to the above embodiments, and many more variations and modifications can be made based on the teachings of this application, all of which fall within the scope of protection claimed in this application. The scope of protection of this application is defined by the appended claims and their equivalents.

Claims

1. A plunger return device, characterized in that, The plunger return device includes: Eccentric shaft; A rotating assembly includes a rotating member, a moving member, and a rolling member, wherein the rolling member is located between the rotating member and the moving member, the rotating member is connected to the eccentric shaft, and the moving member includes an outer peripheral surface, the outer peripheral surface of the moving member including a first outer peripheral portion and a second outer peripheral portion; A first plunger and a second plunger are arranged opposite each other along the radial direction of the eccentric shaft. The first plunger is in contact with the first outer peripheral portion, and the second plunger is in contact with the second outer peripheral portion. Both the first plunger and the second plunger are provided with annular grooves. The annular groove of the first plunger is recessed inward from the outer peripheral surface of the first plunger. The neck diameter of the annular groove of the first plunger is smaller than the working surface diameter of the first plunger. A connecting member, constructed as a retaining ring, rigidly connects the first plunger and the second plunger. The connecting member includes a first free end, a second free end, and an arc-shaped segment. The first free end includes a first retaining groove, and the second free end includes a second retaining groove. The first free end and the second free end are connected via the arc-shaped segment. The first free end engages with the first plunger, and the second free end engages with the second plunger. The first retaining groove includes a first groove wall and a first groove bottom, which are tangent and parallel. The first groove bottom has a clearance fit with the annular groove of the first plunger, with a clearance value of 0.03–0.06 mm. The distance between the first outer peripheral portion and the central axis of the eccentric shaft along the radial direction is different from the distance between the second outer peripheral portion and the central axis of the eccentric shaft along the radial direction. The second groove includes a second groove wall and a second groove bottom. The second groove bottom is in transition fit with the second plunger with a gap of 0.002 to 0.015 mm. The second groove wall includes a first inclined section and a second inclined section. The first inclined section extends inward from the second groove bottom, and the second inclined section extends outward from the first inclined section.

2. The plunger return device according to claim 1, characterized in that, The plunger return device further includes a first plunger cylinder and a second plunger cylinder, wherein the first plunger reciprocates linearly in the first plunger cylinder along the radial direction, and the second plunger reciprocates linearly in the second plunger cylinder along the radial direction.

3. A plunger pump, characterized in that, The plunger pump includes a plunger return device according to any one of claims 1-2, and the plunger pump further includes a first chamber and a second chamber, wherein the first plunger is located in the first chamber and the second plunger is located in the second chamber.

4. The plunger pump according to claim 3, characterized in that, The plunger pump further includes a first port and a second port, the first port communicating with the first chamber and the second port communicating with the second chamber. The first plunger moves toward the second plunger to draw liquid from the first port into the first chamber. The second plunger moves away from the first plunger to discharge the liquid in the second chamber through the second port.

5. The plunger pump according to claim 4, characterized in that, The second plunger moves toward the first plunger to draw liquid from the second port into the second chamber. The first plunger moves away from the second plunger to discharge the liquid in the first chamber through the first port.

6. The plunger pump according to claim 3, characterized in that, The plunger pump also includes a return oil chamber, in which the rotating assembly is disposed. The plunger pump also includes a low-pressure inlet, a first port, and a second port. The first port is connected to the first chamber, and the second port is connected to the second chamber. Both the first port and the second port are connected to the low-pressure inlet, and the return oil chamber is connected to the low-pressure inlet.

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