Transmission assembly and reciprocating pump including the transmission assembly

Abstract

The present application relates to a transmission assembly, which includes: a reciprocating member; a rotating member, which is equipped to rotate relative to the reciprocating member to drive the reciprocating member to perform reciprocating motion; the rotating member is equipped at the bottom of the reciprocating member in the axial direction, wherein one of the reciprocating member and the rotating member has symmetrically distributed protrusions, and the other of the reciprocating member and the rotating member has a track portion, the protrusions are received in the track portion in a manner that can slide within the track portion, and wherein the surface height of the track portion in the axial direction varies periodically along the circumferential direction of the track portion. With the help of this transmission assembly, the conversion between rotational motion and linear reciprocating motion can be achieved in a compact space. The present application also relates to a reciprocating pump including the transmission assembly.

Description

Technical Field

[0001] The present application relates to a transmission assembly, and in particular to a transmission assembly capable of achieving conversion between rotational motion and linear motion in a compact space. The present application also relates to a reciprocating pump comprising the transmission assembly. Background Art

[0002] Transmission assemblies, used to convert rotational motion into linear motion, are a common transmission mechanism and are widely used in various piston-type components. For example, a gear and rack, or a cam and camshaft, can be used to convert the rotational motion of a motor output shaft into linear motion. Traditional designs often require a reduction mechanism to reduce the speed of the rotational motion and thereby increase the output torque.

[0003] Planetary reducers, as a widely applicable reduction mechanism, feature small size, light weight, high load capacity, long service life, smooth operation, and safe performance. However, in traditional designs, components in the transmission assembly must be installed perpendicular to the rotational axis of the planetary reducer and motor output shaft. In other words, while the planetary reducer can be installed along the same axial direction as the motor output shaft, in traditional designs, the transmission assembly cannot be installed along the same axial direction as the planetary reducer and motor output shaft. This increases the overall size of piston-type components, making traditional designs difficult to achieve sufficiently compact assembly requirements in applications requiring high space utilization.

[0004] It should be noted that this background technology section is intended to illustrate the technical background of this application and is not intended to limit the scope of this application. It should also be noted that the technical content provided in this section is intended to help those skilled in the art understand the present invention and does not necessarily constitute prior art. Summary of the Invention

[0005] This section provides a general summary of the invention, and is not a comprehensive disclosure of its full scope or all of its features.

[0006] The present disclosure aims to provide a transmission assembly that can be assembled along the same axial direction, thereby enabling conversion between rotary motion and linear reciprocating motion in a compact space. Another object of the present disclosure is to provide a reciprocating pump comprising the transmission mechanism.

[0007] According to one aspect of the present disclosure, a transmission assembly is provided, which includes: a reciprocating member; a rotating member, which is equipped to be able to rotate relative to the reciprocating member to drive the reciprocating member to perform reciprocating motion; wherein, the rotating member is equipped at the bottom of the reciprocating member along the axial direction, one of the reciprocating member and the rotating member has symmetrically distributed protrusions, and the other of the reciprocating member and the rotating member has a track portion, the protrusion is received in the track portion in a manner that can slide within the track portion, and wherein the surface height of the track portion in the axial direction varies periodically along the circumferential direction of the track portion.

[0008] In the above-mentioned transmission assembly, the protrusion is formed integrally with the one of the reciprocating member and the rotating member.

[0009] In the above transmission assembly, the surface height of the track portion varies non-uniformly in the circumferential direction of the track portion.

[0010] In the above transmission assembly, the rotating component has a plurality of steering columns, and the plurality of steering columns are fixed or integrally formed at the bottom of the rotating component.

[0011] In the above transmission assembly, the surface where the protrusion and the track portion are in sliding contact is a continuous and smooth curved surface.

[0012] In the above transmission assembly, the surface where the protrusion and the rail portion are in sliding contact is an inclined surface.

[0013] According to another aspect of the present disclosure, a reciprocating pump is provided, which includes: a piston assembly, which includes: a piston housing, which has a piston cavity; a piston, which is accommodated in the piston cavity and can reciprocate in an axial direction in the piston cavity, the piston extending in the axial direction and the bottom of the piston is configured to protrude in a radial direction; a motor assembly, which includes a motor housing and a rotating shaft extending from the motor housing, the rotating shaft having output teeth at the tip end; it is characterized in that the reciprocating pump also includes a transmission assembly as described above, which is assembled between the piston assembly and the motor assembly in the same axial direction as the piston and the rotating shaft, wherein the reciprocating member is assembled to be fixed in the rotational direction and the top of the reciprocating member abuts the bottom of the piston, and the rotating member is driven by the output teeth to rotate.

[0014] In the above-mentioned reciprocating pump, the reciprocating pump also includes a reduction mechanism, which includes a plurality of planetary gears and a ring gear, the ring gear is fixed in the rotation direction, and the external teeth of the plurality of planetary gears are engaged with the output teeth and the internal teeth of the ring gear; the number of steering columns of the rotating component is the same as the number of planetary gears of the reduction mechanism, and the steering columns are correspondingly inserted into the corresponding planetary gears to rotate around the rotation axis with the planetary gears.

[0015] In the above reciprocating pump, the piston assembly further includes a spring chamber accommodated in the piston chamber, wherein a spring is accommodated in the spring chamber. The spring is in a compressed state in the spring chamber and one end of the spring abuts against the bottom of the piston.

[0016] In the above reciprocating pump, the piston assembly further includes a sealing ring, which is arranged to abut against the piston and the wall of the piston chamber in a radial direction.

[0017] According to one aspect of the present disclosure, the reciprocating components and the rotating components in the transmission assembly can be assembled along the same axial direction, thereby reducing the space volume occupied by the transmission assembly, so that the transmission assembly can realize the conversion between rotational motion and linear motion in a compact space.

[0018] Advantageously, the protrusion is integrally formed with the one of the reciprocating member and the rotating member to reduce the number of parts and simplify the assembly process.

[0019] Advantageously, the surface height of the track portion in the axial direction varies non-uniformly in the circumferential direction of the track portion, thereby providing different movement speeds for the reciprocating member during rotation of the rotating member relative to the reciprocating member.

[0020] Advantageously, the rotating member has multiple steering columns at its base. These columns can be separate components fixed to the base of the rotating member or integrally formed with the rotating member. With these columns, the rotating member can rotate synchronously with the planetary gears in the planetary reduction mechanism, thereby providing reduced rotational speed and increased torque while simultaneously reducing overall size through coaxial assembly.

[0021] Optionally, the surface of the protrusion in sliding contact with the track portion is a continuous smooth curved surface, such as a continuous smooth spherical curved surface. By means of this all-around contact sliding mode, the protrusion can be stably received in the track portion during the rotation of the rotating member relative to the reciprocating member.

[0022] Advantageously, the surface of the protrusion in sliding contact with the track portion is an inclined surface. With the help of this single-sided contact design, the contact area between the protrusion and the track portion can be reduced, thereby reducing the amount of wear-resistant material used, thereby further reducing production costs.

[0023] Advantageously, the piston assembly of the reciprocating pump further includes a spring chamber housed within the piston cavity, wherein a compressed spring is housed within the spring chamber. One end of the spring abuts against the bottom of the piston. This design ensures close contact between the bottom of the piston and the reciprocating member by virtue of the restoring force of the spring.

[0024] Advantageously, the piston assembly further comprises a sealing ring which abuts against the piston and the wall of the piston chamber in a radial direction, thereby providing a seal for the piston. Such sealing helps the piston to pressurize, for example, a hydraulic fluid. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The features and advantages of one or more embodiments of the present invention will become more readily understood through the following detailed description with reference to the accompanying drawings. It should be understood that the drawings are shown in schematic form only, and the embodiments of the present invention are not limited to the forms shown in the drawings. For clarity, the same or similar components in the drawings are indicated by the same reference numerals. In the drawings:

[0026] Figure 1 Schematically shows an exploded perspective view of a transmission assembly according to an embodiment of the present disclosure;

[0027] Figure 2 Schematically shows the assembled Figure 1 A partial cross-sectional view of a transmission assembly;

[0028] Figure 3 Schematically shows an exploded perspective view of a reciprocating pump according to an embodiment of the present disclosure, wherein some components of the reciprocating pump are omitted for clarity;

[0029] Figure 4 Schematically shows a partial cross-sectional view of a reciprocating pump according to an embodiment of the present disclosure;

[0030] Figure 5 Schematically illustrates the relationship between the axial stroke of the reciprocating member and the circumferential rotational stroke of the rotating member;

[0031] Figure 6 Schematically shows an exploded perspective view of a transmission assembly according to another embodiment of the present disclosure;

[0032] Figure 7 Schematically shows an exploded perspective view of a transmission assembly according to another embodiment of the present disclosure;

[0033] Figure 8 Schematically shows the assembled Figure 7 A partial cross-sectional view of a transmission assembly;

[0034] Figure 9 Schematically shows the method according to the present disclosure Figure 7 A partial cross-sectional view of the reciprocating pump in the transmission assembly;

[0035] Figure 10 Schematically shows an exploded perspective view of a transmission assembly according to another embodiment of the present disclosure;

[0036] Figure 11 and Figure 12 Other embodiments of the protrusion of the transmission assembly are schematically shown. DETAILED DESCRIPTION

[0037] The present invention will be described in detail below with reference to the accompanying drawings using exemplary embodiments. It should be understood that the following detailed description of the present invention is only intended for illustrative purposes and is not intended to limit the present invention and its application or use.

[0038] The directional terms such as "upper" and "lower" used in the specification are only intended to clarify the description in conjunction with the drawings and are not intended to limit the orientation of the relevant components. In actual operation, the positional orientation relationship between components may vary according to specific applications.

[0039] Figure 1 An exploded perspective view of a transmission assembly according to an embodiment of the present disclosure is shown. The transmission assembly 10 includes a reciprocating member 12 capable of linear motion in an axial direction XX and a rotating member 14 capable of rotating relative to the reciprocating member 12 to drive the reciprocating member 12. In this embodiment, the reciprocating member 12 includes a protrusion 16 extending from the bottom of the reciprocating member 12 in the axial direction, and the rotating member 14 includes a track portion 18 located at the top and a steering column 15 integrally formed or fixed to the bottom. The track portion 18 is used to receive the protrusion 16 of the reciprocating member 12, and the surface height of the track portion 18 in the axial direction varies periodically in the circumferential direction. Exemplarily, the reciprocating member 12 also includes a locking groove 13, which is arranged at the periphery of the reciprocating member 12 to fix the reciprocating member 12 in the rotational direction by means of cooperation with the locking pin 17 described below.

[0040] Figure 2The transmission assembly 10 is shown in an assembled state. As shown, the continuously smooth curved bottom of the protrusion 16 of the reciprocating member 12 is received in the track portion 18 of the rotating member 14. Because the surface height of the track portion 18 varies periodically in the circumferential direction, during the rotation of the rotating member 14 relative to the reciprocating member 12 along the rotation axis XX, the reciprocating member 12 undergoes linear reciprocating motion in the axial direction following the undulations in the track portion 18 of the protrusion 16. In particular, because the rotation axis XX of the rotating member 14 and the axial direction of the linear reciprocating motion of the reciprocating member 12 are the same, the reciprocating member 12 can achieve the conversion from rotary motion to linear reciprocating motion when assembled with the rotating member 14 along the same axial direction. Compared to traditional cam / camshaft assemblies or gear / rack assemblies, this coaxial assembly significantly reduces the assembly space and, therefore, the overall volume of the assembly, enabling the transmission assembly 10 to achieve the conversion between rotary motion and linear motion in a compact space.

[0041] Figure 3 The figure shows an exploded perspective view of a reciprocating pump 1 including the transmission assembly 10 in the above embodiment. For the sake of clarity, some components are omitted. As shown in the figure, the reciprocating pump 1 generally includes a piston assembly 20, a transmission assembly 10, a reduction mechanism 40, and a motor assembly 30. The motor assembly 30 further includes a motor housing 31 and a rotating shaft 32 extending from the motor housing 31, and the rotating shaft 32 has an output tooth 33 at its tip end. The specific structure and assembly relationship of other components and mechanisms will be referred to below. Figure 4 Detailed description. Figure 3 It can be seen that, with the aid of the transmission assembly 10 provided by the present disclosure, the piston assembly 20, the transmission assembly 10, the reduction mechanism 40 and the motor assembly 30 can be coaxially assembled along the same axial direction, making the overall structure of the reciprocating pump 1 more compact.

[0042] exist Figure 3 In the illustrated embodiment, the reciprocating member 12 in the transmission assembly 10 is coupled to the piston assembly in a rotationally fixed manner by means of the engagement of the locking groove 13 with the locking pin 17. Those skilled in the art will appreciate that this coupling arrangement is for illustrative purposes only and is not intended to limit the present invention.

[0043] Figure 4 The figure further shows a partial cross-sectional view of the reciprocating pump 1 including the transmission assembly 10 in the above embodiment. Figure 4As shown in FIG, the piston assembly 20 further includes: a piston housing 21 having a piston cavity 22; a piston 23 housed within the piston cavity 22 and capable of reciprocating axially therein; the piston 23 extending axially and having a bottom portion protruding radially; a spring cavity 24 housed within the piston cavity 22, containing a spring 25 compressed within the spring cavity 24 and having one end abutting against the bottom portion of the piston 23; and a sealing ring 26 configured to radially abut the piston 23 and the wall of the piston cavity 22. The bottom portion of the piston 23 abuts the top portion of the reciprocating member 12 in the transmission assembly 10. Due to the abutment of the compressed spring 25 within the spring cavity 24 on the opposite side of the bottom portion of the piston 23, the bottom portion of the piston 23 is consistently in close contact with the reciprocating member 12. The reduction mechanism 40 further includes planetary gears 41 and a rotationally fixed ring gear 42. The outer teeth of the planetary gears 41 mesh with the inner teeth of the ring gear 42 and the output teeth 33 of the rotating shaft 32. The steering columns 15 of the rotating components 14 in the transmission assembly 10 are inserted into the corresponding planetary gears 41 in a one-to-one correspondence. The reciprocating component 12 in the transmission assembly 10 is connected to the piston housing 21, for example, by the cooperation of the locking groove 13 and the locking pin 17, so that the reciprocating component 12 is fixed in the rotational direction and reciprocates only in the axial direction. Specifically, the locking pin 17 is embedded or integrally formed in the piston housing 21 and is received in the locking groove 13 of the reciprocating component 12 during assembly, thereby enabling the locking groove 13 of the reciprocating component 12 to perform linear reciprocating motion in the axial direction along the locking pin 17. At the same time, due to the cooperation between the locking groove 13 and the locking pin 17, the movement of the reciprocating component 12 in the rotational direction is locked.

[0044] exist Figure 3 and Figure 4 In the embodiment shown, the reduction mechanism 40 includes three planetary gears 41 arranged at equal intervals along the circumferential direction, and the rotating member 14 includes three steering columns 15. However, the present invention is not limited thereto and may include any number of planetary gears and steering columns.

[0045] During operation of the reciprocating pump 1, the motor assembly 30's rotating shaft 32 drives the planetary gears 41 to rotate, driven by the meshing of the motor's output teeth 33 with the external teeth of the planetary gears 41. Simultaneously, because the ring gear 42 is fixed in its rotational direction, the planetary gears 41, meshing with the internal teeth of the ring gear 42, simultaneously rotate and orbit around the rotating shaft 32, causing the steering column 15 and rotating member 14, which are inserted into the planetary gears 41, to rotate synchronously with the orbital rotation of the planetary gears 41. Because the radius of the ring gear 42 is significantly larger than the radius of the output teeth 33, the rotational motion of the planetary gears 41 about the rotating shaft 32 is decelerated relative to the rotational speed of the rotating shaft 32. Furthermore, because the steering column 15 of the rotating member 14 is inserted into the planetary gears 41, the planetary gears 41 drive the rotating member 14 to rotate at a reduced speed.

[0046] Because the track portion 18 of the rotating member 14 has a surface height that periodically changes in the circumferential direction, when the rotating member 14 revolves with the planetary gear 41, the protrusion 16 received in the track portion 18 will perform linear reciprocating motion in the axial direction as the surface height of the track portion 18 changes, thereby causing the reciprocating member 12 and the piston 23 to perform linear reciprocating motion in the axial direction. As a result, it is possible to achieve conversion from rotational motion to linear reciprocating motion when the reciprocating member 12 and the rotating member 14 are mounted in the same axial direction.

[0047] It should be pointed out that Figure 4 The central protrusion 16 is shown as a separate component fastened to the reciprocating member 12, but the protrusion 16 may also be integrally formed with the reciprocating member 12. In addition, it should be understood that the reciprocating pump 1 may also not include the reduction gear mechanism 40 if it is not necessary to reduce the output speed of the rotating shaft 32. In this case, the rotating member 14 is driven directly by the rotating shaft 32 without passing through the reduction gear mechanism. For example, the bottom of the rotating member 14 may be configured to have internal teeth that mesh with the output teeth 33 of the rotating shaft 32, or the steering column 15 of the rotating member 14 may be configured to have a toothed portion (not shown) that meshes with the output teeth 33.

[0048] Figure 5The relationship between the axial stroke h of the reciprocating member 12 and the circumferential rotation stroke S of the rotating member 14 is schematically shown. Since the surface height of the track portion 18 can be designed to vary non-uniformly along the circumferential direction, for the same axial displacement h0 of the reciprocating member 12, the circumferential displacement of the rotating member 14 can correspond to different circumferential strokes S1 and S2. This non-uniform variation will cause the reciprocating motion of the reciprocating member 12 to have different motion speeds at different times depending on the needs of the specific application. For example, when the piston is compressed, the circumferential stroke S1 of the rotating member is larger, and when the piston returns, the circumferential stroke S2 ​​of the rotating member is smaller. The specific variation relationship between the axial stroke h of the reciprocating member 12 and the circumferential rotation stroke S of the rotating member 14 can be changed according to the actual application. In addition, it should be understood that when the reciprocating member 12 is required to move at a uniform speed, the surface height of the track portion 18 can also be designed to vary uniformly along the circumferential direction.

[0049] Figure 6 A variation of the transmission assembly 10 described above is shown. Figure 6 In the embodiment of FIG. 1 , the reciprocating member 12 has a track portion 18 and the rotating member 14 has a protrusion 16 . Similarly, because the surface height of the track portion 18, which receives the protrusion 16, varies periodically along the circumferential direction, the reciprocating member 12 will perform linear reciprocating motion in the axial direction as the rotating member 14 rotates relative to the reciprocating member 12. Similarly, this variation also allows for coaxial assembly of the reciprocating member 12 and the rotating member 14.

[0050] Figure 7 and Figure 8 Another embodiment of the transmission assembly 10 is shown. In the embodiment shown, the track portion 18 is an annular inclined surface with different heights along the circumferential direction, and correspondingly, the protrusion 16 is constructed to have an inclined surface that cooperates with the track portion 18, so that it can be received in the track portion 18. Compared with the track portion 18 and the protrusion 16 in the aforementioned embodiment, which are curved, this single-sided contact design of the inclined protrusion 16 and the track portion 18 can reduce the contact area between the two. Since the contact portion between the track portion 18 and the protrusion 16 is usually preferably made of wear-resistant material, this design can reduce the amount of wear-resistant material used, thereby reducing production costs. It should be understood that the protrusion 16 is constructed to be elongated, so the protrusion 16 contacts the track portion 18 only at the two end sides of the elongation, and does not contact the track portion 18 on the elongated side of the protrusion, so wear-resistant material can be used only at the inclined surfaces on both sides of the protrusion 16.

[0051] Figure 9 FIG. 1 shows a partial cross-sectional view of a reciprocating pump 1 including the transmission assembly 10 described above. Figure 4, the rotating shaft 32 in the motor assembly 30 drives the planetary gears 41 to rotate. Because the ring gear 42 is rotationally locked, the planetary gears 41 rotate while also orbiting around the rotating shaft 32, causing the steering column 15 and the rotating member 14, which are inserted into the planetary gears 41, to rotate with the orbital revolution of the planetary gears 41. Because the track portion 18 of the rotating member 14 is an inclined surface with different axial heights in the circumferential direction, as the rotating member 14 rotates relative to the reciprocating member 12, the protrusion 16 in contact with the track portion 18 will undergo linear reciprocating motion in the axial direction as the height of the inclined surface of the track portion 18 changes, thereby causing the reciprocating member 12 and the piston 23 to undergo linear reciprocating motion in the axial direction.

[0052] Figure 10 A variation of the transmission assembly 10 described above is shown. Figure 10 In the embodiment of the present invention, the reciprocating member 12 has a track portion 18 and the rotating member 14 has a protrusion 16. Similarly, because the height of the inclined surface of the track portion 18 in contact with the protrusion 16 varies periodically along the circumferential direction, as the rotating member 14 rotates relative to the reciprocating member 12, the reciprocating member 12 will perform linear reciprocating motion in the axial direction.

[0053] Figure 11 and Figure 12 Different embodiments of the protrusion 16 in the transmission assembly 10 are shown. As previously mentioned, Figure 11 and Figure 12 The protrusion 16 in the embodiment can be formed on either the reciprocating member 12 or the rotating member 14. Since the protrusion 16 is in sliding contact with the track portion 18 only on both sides, Figure 11 and Figure 12 As shown in , the central portion of the protrusion 16 can be designed to have a reduced volume, thereby reducing the material used in the protrusion 16 to further reduce the overall weight and production cost.

[0054] As described above, this application discloses some embodiments and mentions some possible alternatives, all of which are within the scope of protection of this application. In addition, some obvious modifications that a person of ordinary skill in the art would recognize would also fall within the scope of protection of this application.

[0055] Although the present invention has been described with reference to exemplary embodiments, it should be understood that the invention is not limited to the specific embodiments / examples described and shown in detail herein, and that various changes may be made to the exemplary embodiments by those skilled in the art without departing from the scope defined by the appended claims.

Claims

1. A transmission assembly (10), characterized in that: The transmission assembly (10) comprises: a reciprocating member (12); a rotating member (14) configured to be rotatable relative to the reciprocating member (12) to drive the reciprocating member (12) to perform reciprocating motion; wherein the rotating member (14) is fitted at the bottom of the reciprocating member (12) in the axial direction, one of the reciprocating member (12) and the rotating member (14) has symmetrically distributed protrusions (16), the other of the reciprocating member (12) and the rotating member (14) has a track portion (18), the protrusions (16) are received in the track portion (18) in a manner capable of sliding within the track portion (18), and wherein the surface height of the track portion (18) in the axial direction changes periodically along the circumferential direction of the track portion (18); and The protrusion (16) is formed integrally with the one of the reciprocating member (12) and the rotating member (14), or the protrusion is a separate component fastened to the one of the reciprocating member (12) and the rotating member (14).

2. The transmission assembly (10) according to claim 1, characterized in that The surface height of the track portion (18) varies non-uniformly in the circumferential direction of the track portion (18).

3. The transmission assembly (10) according to claim 2, characterized in that The rotating component (14) has a plurality of steering columns (15), and the plurality of steering columns (15) are fixed or integrally formed at the bottom of the rotating component (14).

4. The transmission assembly (10) according to any one of claims 1 to 3, characterized in that The surface where the protrusion (16) and the track portion (18) are in sliding contact is a continuous and smooth curved surface.

5. The transmission assembly (10) according to any one of claims 1 to 3, characterized in that The surface of the protrusion (16) in sliding contact with the track portion (18) is an inclined surface.

6. A reciprocating pump (1), comprising: A piston assembly (20) comprising: a piston housing (21), the piston housing (21) having a piston cavity (22); a piston (23), the piston (23) being accommodated in the piston cavity (22) and capable of reciprocating in the piston cavity (22) along an axial direction, the piston (23) extending in the axial direction and the bottom of the piston (23) being configured to protrude in a radial direction; A motor assembly (30), comprising a motor housing (31) and a rotating shaft (32) extending from the motor housing (31), wherein the rotating shaft (32) has output teeth (33) at a distal end thereof; It is characterized in that the reciprocating pump (1) further includes a transmission assembly (10) according to any one of claims 1 to 5, the transmission assembly (10) being assembled between the piston assembly and the motor assembly along the same axial direction as the piston (23) and the rotating shaft (32), wherein the reciprocating member (12) is assembled to be fixed in the rotational direction and the top of the reciprocating member (12) abuts the bottom of the piston (23), and the rotating member (14) is driven by the output teeth (33) to rotate.

7. The reciprocating pump (1) according to claim 6, characterized in that The reciprocating pump (1) further includes a reduction mechanism (40), the reduction mechanism (40) including a plurality of planetary gears (41) and a ring gear (42), the ring gear (42) being fixed in the rotation direction, the outer teeth of the plurality of planetary gears (41) meshing with the output teeth (33) and the inner teeth of the ring gear (42), and the number of steering columns (15) of the rotating member (14) is the same as the number of the planetary gears (41) of the reduction mechanism (40), and the steering columns (15) are correspondingly inserted into the corresponding planetary gears (41) to rotate with the planetary gears (41) around the rotation axis (32).

8. The reciprocating pump (1) according to claim 6 or 7, characterized in that The piston assembly (20) further includes a spring chamber (24) accommodated in the piston chamber (22), wherein a spring (25) is accommodated in the spring chamber (24), wherein the spring (25) is in a compressed state in the spring chamber (24) and one end of the spring (25) abuts against the bottom of the piston (23).

9. The reciprocating pump (1) according to claim 8, characterized in that The piston assembly (20) further comprises a sealing ring (26), which is arranged to abut against the piston (23) and the wall of the piston chamber (22) in a radial direction.

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