CN116658414A - Swash plate plunger type hydraulic pump - Google Patents

Abstract

The invention relates to the field of hydraulic pumps, in particular to a swash plate plunger type hydraulic pump. The swash plate plunger type hydraulic pump comprises a shell and a plunger, wherein a liquid outlet channel communicated with a plunger cavity is formed in the shell, a liquid outlet one-way valve is further arranged in the liquid outlet channel, a liquid inlet channel communicated with the plunger cavity is further formed in the shell, the plunger comprises a solid section, the solid section is matched with the plunger cavity to separate the plunger cavity from the oil cavity, two ends of the liquid inlet channel are respectively communicated with the oil cavity and the plunger cavity, and a liquid inlet one-way valve is arranged in the liquid inlet channel. Through set up the feed liquor passageway that communicates the plunger chamber on the casing and make the position of advance oil become the casing by the plunger, separate fluid chamber and plunger chamber through solid section, and then set up the through-hole oil feed on the plunger among the prior art, and there is the clearance for sliding fit between plunger and the main shaft and then lead to taking place in the inclined disc face easily to leak and cause fluid loss even unable pump oil's problem.

Description

Swash plate plunger type hydraulic pump

Technical Field

The invention relates to the field of hydraulic pumps, in particular to a swash plate plunger type hydraulic pump.

Background

The hydraulic transmission technology has the advantages of high power density, convenient control, high response speed, accurate displacement/force control and the like, and is widely applied to various fields of national economy construction such as transportation, engineering construction, resource exploitation and the like. Along with the development demands of greening, lightening and electrodynamic high-end equipment such as aviation aircrafts, foot robots, mobile machinery, deep sea diving equipment and the like, hydraulic pumps are driven to develop towards miniaturization and high-pressure.

The Chinese patent application with the application publication number of CN109798231A discloses a tilting tray type miniature plunger pump, wherein the tilting tray type miniature plunger pump comprises a main shaft tilting tray (namely a main shaft), a sliding shoe, a return tray, a return rod, a plunger and a plunger cylinder body, wherein the main shaft tilting tray is in sliding fit with the sliding shoe, one end of the plunger is in spherical fit with a spherical cavity on the sliding shoe, and the other end of the plunger is matched with the plunger cylinder body. In order to facilitate the transmission of hydraulic oil, a waist-shaped hole is formed in the main shaft sloping cam plate, a through hole is formed in the axis position of the plunger, and the through hole is communicated with a plunger cavity in the plunger cylinder body. When the sliding shoe is staggered with the kidney-shaped hole, the plunger also compresses the volume of the plunger cavity, so that the oil in the plunger cavity flows to the outlet along the flow passage, and further continuous operation of the plunger pump is realized.

According to the technical scheme, the plunger pump oil is sucked by punching holes in the plunger, oil is fed through the cooperation of the sliding shoe and the main shaft swash plate, however, the main shaft inclined surface and the sliding shoe are in sliding fit, so that gaps can be formed between the sliding shoe and the main shaft inclined surface, when the plunger pumps oil outwards, part of the oil in the plunger cavity can escape outwards along the gaps between the sliding shoe and the main shaft inclined surface, internal leakage is caused, and the oil quantity pumped by the plunger back and forth once is smaller than that of actual oil even can not be pumped.

Disclosure of Invention

The invention aims to provide a swash plate plunger type hydraulic pump, which is used for solving the problems that in the prior art, through holes are formed in plungers for oil feeding, gaps exist between the plungers and a main shaft in a sliding fit mode, so that internal leakage easily occurs on a swash plate surface, oil is lost, and even oil cannot be pumped.

In order to achieve the above purpose, the swash plate plunger type hydraulic pump of the present invention adopts the following technical scheme:

the utility model provides a sloping cam plate plunger type hydraulic pump, including casing and plunger, be provided with the fluid import on the casing, be provided with fluid chamber and plunger chamber in the casing, the one end of plunger inserts the plunger intracavity and is used for changing the volume in plunger chamber, be provided with the drain passageway with plunger chamber intercommunication on the casing, be provided with out the liquid check valve in the drain passageway, the plunger is including the solid section that is used for making plunger chamber and fluid chamber non-intercommunication, be provided with the feed liquor passageway on the casing, the inlet and the fluid chamber intercommunication of feed liquor passageway, the liquid outlet and the plunger chamber intercommunication of feed liquor passageway are provided with the feed liquor check valve in the feed liquor passageway.

The beneficial effects of the technical scheme are that: the invention improves the prior swash plate plunger type hydraulic pump, and the position of oil inlet is changed from a plunger to a shell by arranging the liquid inlet channel communicated with the plunger cavity on the shell, so that the plunger does not need to open a hole at the axis, and further the plunger can comprise a solid section, and the oil cavity and the plunger cavity are separated from communication by the solid section, so that the oil in the oil cavity is directly sucked without passing through a through hole on the plunger when the plunger reciprocates; through setting up the check valve, can selectively make plunger chamber and feed liquor passageway or drain passage intercommunication for fluid one-way flow in feed liquor passageway and drain passage, and then set up the through-hole oil feed on the plunger among the prior art, and for sliding fit existence clearance between plunger and the main shaft and then lead to taking place in the inclined disc face easily to leak and cause the problem that fluid loss can't pump oil even.

Further, a one-way valve mounting hole and an oil suction hole communicated with the oil cavity are formed in the shell, the oil suction hole forms an inlet of the liquid inlet channel, the one-way valve mounting hole is arranged towards the outer side of the shell, and a plugging piece is mounted in the one-way valve mounting hole.

The beneficial effects of the technical scheme are that: the installation is convenient, and the blocking piece can be used for blocking the check valve mounting hole after installation, so that oil leakage is avoided.

Further, an operation hole extending to the inner side of the plugging piece is formed in the plugging piece.

The beneficial effects of the technical scheme are that: the installation of the plugging piece is convenient, and the weight reduction of the device is also convenient.

Further, a pipe body structure protruding relative to the surface of the shell is arranged on the shell, and the check valve mounting hole is arranged in the pipe body structure.

The beneficial effects of the technical scheme are that: the installation of the check valve mounting hole is facilitated, and the overlarge outer diameter of the shell is avoided.

Further, at least four pipe structures are uniformly arranged on the shell, the number of the pipe structures is the same as that of the plunger cavities, the pipe structures correspond to that of the plunger cavities one by one, and the axes of the pipe structures are tangent lines of the same circle.

The beneficial effects of the technical scheme are that: compact structure, pump oil is efficient, and the equipartition sets up the in-process that makes sloping cam plate plunger type hydraulic pump in the motion, and pump oil is more even.

Further, the swash plate plunger type hydraulic pump includes a shoe including a shoe return body and a shoe support body engaged by threads, with a ball socket formed therebetween for receiving an end of the plunger.

The beneficial effects of the technical scheme are that: the size of the ball socket is variable through the sliding shoe return body and the sliding shoe supporting body which are matched through the threads, when the plunger and the ball socket are worn, and a gap is formed between the plunger and the ball socket, the gap between the ball socket and the end part of the plunger can be reduced through adjusting the threads, and further impact and vibration caused by the fact that the gap exists during reciprocating motion of the plunger are avoided.

Further, the sliding shoe return body and the sliding shoe supporting body are provided with anti-loosening structures for preventing the sliding shoe return body and the sliding shoe supporting body from loosening.

The beneficial effects of the technical scheme are that: avoiding looseness between the slipper return body and the slipper support body during movement.

Further, a circumferential array of rotation stopping grooves are formed in the sliding shoe return body, pin holes are formed in the sliding shoe support body, and pins are arranged in the pin holes and are matched with the rotation stopping grooves to stop rotation.

The beneficial effects of the technical scheme are that: the structure is simple, the main shaft can be utilized to limit the pin, and the pin is prevented from falling off.

Further, the swash plate plunger type hydraulic pump further comprises a main shaft, a sliding shoe and a return disc, a threaded hole is formed in the end face of the main shaft, the return disc and the sliding shoe are limited through a fixing bolt assembled in the threaded hole, the fixing bolt penetrates through the return disc to be in threaded fit with the threaded hole, and the bolt head of the fixing bolt is used for being in stop fit with the return disc.

The beneficial effects of the technical scheme are that: the gap between the inclined surface end of the main shaft and the sliding shoe can be adjusted, the friction force between the inclined surface end of the main shaft and the sliding shoe can be conveniently adjusted, and meanwhile, the main shaft is firmly connected, and is convenient to bear larger moment.

Further, the swash plate plunger type hydraulic pump also comprises a main shaft and a sliding shoe, wherein the main shaft comprises a main shaft body and a wear-resistant disc arranged on the end face of the main shaft body, and the wear-resistant disc is in sliding contact fit with the sliding shoe.

The beneficial effects of the technical scheme are that: the material and the forming means of the wear-resistant disc can be independently improved, the wear resistance of the wear-resistant disc is improved, and the damage of the main shaft is avoided.

Drawings

FIG. 1 is a schematic structural view of an embodiment 1 of a swash plate plunger type hydraulic pump according to the present invention;

FIG. 2 is a view from A-A in FIG. 1;

FIG. 3 is a schematic diagram showing the fit of shoes and plungers of example 1 of a swash plate plunger hydraulic pump according to the present invention;

FIG. 4 is a schematic view showing the structure of a plunger of embodiment 1 of a swash plate plunger type hydraulic pump according to the present invention;

FIG. 5 is a rear view of a shoe in embodiment 1 of a swash plate plunger type hydraulic pump of the present invention;

FIG. 6 is a schematic view showing the construction of a shoe return body in embodiment 1 of a swash plate plunger type hydraulic pump according to the present invention;

FIG. 7 is a side view of the slipper return body of example 1 of the swash plate plunger hydraulic pump of the present invention;

FIG. 8 is a schematic view showing the structure of a cylinder block in embodiment 1 of a swash plate plunger type hydraulic pump according to the present invention;

FIG. 9 is a side view of a cylinder block in embodiment 1 of a swash plate plunger type hydraulic pump of the present invention;

fig. 10 is a schematic structural view of a housing body in embodiment 1 of a swash plate plunger type hydraulic pump according to the present invention.

In the figure: 11. a main shaft body; 12. abrasion-resistant disc; 13. a fixing screw; 21. a slipper support body; 22. a slipper return body; 221. a rotation stopping groove; 23. a pin; 24. a lubrication oil passage; 31. a housing body; 311. an oil inlet; 32. a cylinder; 321. a plunger cavity; 322. a liquid inlet; 324. a check valve mounting hole; 33. a valve seat; 34. a screw plug; 35. a liquid inlet one-way valve; 36. a liquid outlet one-way valve; 4. a return tray; 5. a plunger; 51. a spherical end; 52. a cylindrical end; 6. an end cap; 71. a seal ring; 72. a bearing; 73. and (5) clamping springs.

Detailed Description

The features and capabilities of the present invention are described in further detail below in connection with the examples.

In example 1 of the swash plate plunger hydraulic pump in the present invention:

in this embodiment, the hydraulic channel is arranged on the shell, the plunger is arranged to be a closed piece, and the plunger cavity connected with the hydraulic channel is arranged, so that oil flows from the hydraulic channel after being compressed by the plunger, meanwhile, the hydraulic channel comprises a liquid inlet channel and a liquid outlet channel, and one-way valves are arranged in the liquid inlet channel and the liquid outlet channel, so that the plunger can be selectively communicated with the liquid inlet channel or the liquid outlet channel when moving, and further the oil in the liquid inlet channel can be continuously conveyed to the liquid outlet channel.

As shown in fig. 1, a swash plate plunger type hydraulic pump (hereinafter referred to as a plunger pump) in the present embodiment includes a housing, a main shaft rotatably provided in the housing through a bearing 72 and sealed by a seal ring 71, a shoe, a plunger 5, and an end cap 6. The shell comprises a shell body 31 and a cylinder body 32, wherein the cylinder body 32 is fixedly connected with the shell body 31 through a thread section and an oil cavity is formed between the cylinder body and the shell body. As shown in fig. 1, 9 and 10, an oil inlet 311 is further provided on the housing body 31, a plunger cavity 321 and a hydraulic channel are provided on the cylinder 32, the plunger cavity 321 and the hydraulic channel are mutually communicated, and along with the reciprocating motion of the plunger 5 in the plunger cavity 321, the plunger cavity 321 can be extruded to drive oil to flow in the plunger cavity 321. The end cover 6 is fixedly connected to the cylinder 32, and an oil outlet communicated with a liquid outlet of a hydraulic channel on the cylinder 32 is arranged on the end cover 6. That is, the oil flows in from the oil inlet 311 of the housing body 31, passes through the plunger cavity 321 and the hydraulic passage, and flows out from the oil outlet of the end cover 6, thereby completing the directional movement of the oil.

The main shaft comprises a main shaft body 11 and a wear-resistant disc 12, the main shaft body 11 is of a generally cylindrical structure, a step section protruding out of the radial direction of the main shaft body 11 is arranged on the end face of the main shaft body 11, and a clamp spring 73 is further arranged on one end, extending out of the shell, of the main shaft body 11 to limit the position of the main shaft, so that the relative movement of the main shaft and the position of the shell is avoided. The stepped section of the main shaft body 11 constitutes a bevel end, a threaded hole is formed in the bevel end, and a fixing bolt is assembled in the threaded hole. An opening is provided in the middle of the wear plate 12 for the passage of a set screw 13. The end face of one end, far away from the main shaft body 11, of the wear-resistant disc 12 is also in abutting contact with a plurality of sliding shoes, 4 sliding shoes are arranged in the embodiment, and the relative positions of the 4 sliding shoes are kept unchanged through the return disc 4. Specifically, the return disc 4 is provided with perforations on the axis for the fixing bolts to pass through and is in press fit with the bolt heads of the fixing bolts, and 4 sliding shoe perforations for the sliding shoes to pass through and to be fixed are uniformly distributed on the disc surface of the return disc 4. That is, the fixing bolts define the return tray 4 at the corresponding positions, and the return tray 4 fixes the shoe at the corresponding positions through the shoe penetration holes.

As shown in fig. 4, the plunger 5 is entirely a solid section including a spherical end 51 at the end of the plunger 5 and a cylindrical end 52 at the other end, the spherical diameter of the spherical end 51 being larger than the diameter of the cross section of the cylindrical end 52. Spherical end 51 is in hinged engagement with the shoe and cylindrical end 52 extends into cylinder 32. The construction of each shoe is identical, one of which is described as an example. As shown in fig. 3, the shoe includes a shoe return body 22 and a shoe support body 21 which are engaged by screw threads, the shoe return body 22 and the shoe support body 21 being provided with spherical recesses, respectively, and the shoe return body 22 and the shoe support body 21 being engaged with each other to form a ball socket therebetween for receiving the spherical end 51 of the plunger 5. The plunger pump further includes a locking structure on the shoe return body 22 and the shoe support body 21 to prevent the shoe return body 22 and the shoe support body 21 from being released from each other. Specifically, as shown in fig. 6 and 7, in this embodiment, a circumferential array of rotation stopping grooves 221 are provided on the sliding shoe return body 22, as shown in fig. 3 and 5, pin holes through which pins 23 pass are provided on the sliding shoe support body 21, and pins 23 are inserted, and when the sliding shoe return body 22 and the sliding shoe support body 21 move in place, the pins 23 cooperate with the rotation stopping grooves 221 to perform rotation stopping. In addition, the end face of the sliding shoe support body 21, which is in contact with the wear-resistant disc 12, is provided with a cross-shaped lubricating oil duct 24, and oil can enter between the sliding shoe support body 21 and the wear-resistant disc 12 through the lubricating oil duct 24, so that friction force between the sliding shoe support body 21 and the wear-resistant disc 12 is reduced, and heat generated by friction can be taken away.

The cylinder 32 is provided with a plunger cavity 321 into which the cylindrical end 52 of the plunger 5 is inserted, the hydraulic channel comprises a liquid inlet channel located at the upstream of the plunger cavity 321 and a liquid outlet channel located at the downstream of the plunger cavity 321, a liquid inlet 322 of the hydraulic channel is arranged at one end of the cylinder 32 facing the oil cavity and is communicated with the oil cavity, namely, the liquid inlet 322 is arranged in the liquid inlet channel, and the liquid inlet 322 on the cylinder 32 is parallel to the axis of the plunger cavity 321, and in the embodiment, the liquid inlet 322 is an oil suction hole. The liquid outlet is arranged on the liquid outlet channel and is used for pumping out the oil liquid, the valves used for enabling the oil liquid to flow unidirectionally from the liquid inlet 322 to the liquid outlet are respectively arranged in the liquid inlet channel and the liquid outlet channel of the hydraulic channel, the valves are arranged to be ball valves pushed by springs in the embodiment, and the structure of the ball valves is in the prior art and is not repeated here.

As shown in fig. 2, 8 and 9, the cylinder 32 is further provided with 4 pipe structures protruding relative to the surface of the housing, that is, the number of the pipe structures is the same as that of the plunger cavities 321 and corresponds to the positions one by one, and the axes of the pipe structures are tangent lines of the same circle. Be provided with the check valve mounting hole 324 of intercommunication hydraulic pressure passageway in the body structure, check valve mounting hole 324 and the ball valve intercommunication of plunger chamber 321 upper reaches, make things convenient for the check valve in the feed liquor passageway, and conveniently use the shutoff piece to carry out the shutoff to the installing port here after the ball valve is accomplished in the installation. The sealing member in this embodiment includes a valve seat 33 and a screw plug 34, and the valve seat 33 and the screw plug 34 are respectively provided with an operation hole through which not only the installation is facilitated, but also the weight of the sealing member can be reduced. The blocking is performed by the blocking member so that the hydraulic passage communicates with the outside of the cylinder 32 only through the liquid inlet 322 and the liquid outlet of the hydraulic passage.

When the plunger pump moves, the main shaft rotates, the wear-resistant disc 12 swings around the center in the process of rotating the main shaft, so that the sliding shoes at the contact positions with the wear-resistant disc 12 slide relatively, and the sliding shoes reciprocate in the axial direction of the sliding shoes, so that the plunger 5 is driven to reciprocate. When the plunger 5 moves outwards, negative pressure is formed in the plunger cavity 321, so that the liquid inlet one-way valve 35 in the liquid inlet channel is opened, oil enters the liquid inlet channel from the oil cavity to finish oil absorption, when the plunger 5 moves inwards, the space in the plunger cavity 321 is extruded, and the liquid outlet one-way valve 36 in the liquid outlet channel is opened, so that liquid is extruded from the liquid outlet channel to finish oil pumping.

In embodiment 2 of the swash plate plunger type hydraulic pump of the present invention: in view of the arrangement of the spindle, this embodiment proposes a new arrangement, unlike embodiment 1, in which the spindle includes a spindle body without providing a wear-resistant disc, and the end face of the spindle body is in direct contact with the shoe.

In embodiment 3 of the swash plate plunger type hydraulic pump of the present invention: in contrast to embodiment 1, the present embodiment proposes a new arrangement for the setting of the return disc, in which the spindle and the return disc are no longer connected by a fixing bolt, but are pressed against the spindle by an elastic element located on the cylinder.

In embodiment 4 of the swash plate plunger type hydraulic pump of the present invention: in view of the arrangement of the locking structure, this embodiment proposes a new arrangement form, unlike embodiment 1, in which the locking structure is an adhesive tape that bonds the shoe return body and the shoe support body together. Of course, in other embodiments, the anti-loosening structure may not be provided.

In embodiment 5 of the swash plate plunger type hydraulic pump of the present invention: in respect of the arrangement of the sliding shoes, this embodiment proposes a new arrangement form, unlike embodiment 1, in which the sliding shoes are not a separate structure but an integrally formed structure with spherical cavities.

In example 6 of the swash plate plunger type hydraulic pump of the present invention: with respect to the arrangement of the tube structures, this embodiment proposes a new arrangement form, unlike embodiment 1, in this embodiment, four tube structures that are uniformly distributed are not arranged any more, but the number of tube structures is 5, and of course, in other embodiments, the number of tube structures may be less than 4, for example, 3.

In embodiment 7 of the swash plate plunger type hydraulic pump of the present invention: with respect to the arrangement of the tube structures, this embodiment proposes a new arrangement form, unlike embodiment 1, in this embodiment, the number and positions of the tube structures and the plunger cavities are not in one-to-one correspondence, where two tube structures correspond to 1 plunger cavity.

In embodiment 8 of the swash plate plunger type hydraulic pump of the present invention: in view of the arrangement of the check valve mounting hole, this embodiment proposes a new arrangement form, unlike embodiment 1, in which the check valve mounting hole is no longer provided in the pipe body structure but provided on the cylinder body.

In embodiment 9 of the swash plate plunger type hydraulic pump of the present invention: in view of the arrangement of the plugging member, this embodiment proposes a new arrangement form, unlike embodiment 1, in this embodiment, the plugging member is no longer provided with an operation hole, but is provided with a force application hexagonal prism protruding from the plugging member.

In embodiment 10 of the swash plate plunger type hydraulic pump of the present invention: in view of the arrangement of the housing, this embodiment proposes a new arrangement form, unlike embodiment 1, in this embodiment, the check valve mounting hole is not provided any more, but the check valve is provided at the junction of the cylinder body and the housing body.

In embodiment 11 of the swash plate plunger type hydraulic pump of the present invention: in view of the arrangement of the plunger, this embodiment proposes a new arrangement form, unlike embodiment 1, in which the plunger is no longer entirely solid but further includes hollow sections, and the solid sections are staggered with the hollow sections.

In embodiment 12 of the swash plate plunger type hydraulic pump of the present invention: in view of the arrangement of the spindle, this embodiment proposes a new arrangement, unlike embodiment 1, in which the housing is not subdivided into a housing body and a cylinder body connected by a thread segment, but into a housing body and an end cap arranged on the housing body.

The above description is only a preferred embodiment of the present invention, and the patent protection scope of the present invention is defined by the claims, and all equivalent structural changes made by the specification and the drawings of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. The utility model provides a sloping cam plate plunger type hydraulic pump, includes casing and plunger (5), is provided with fluid import (311) on the casing, is provided with fluid chamber and plunger chamber (321) in the casing, and the one end in plunger (5) inserts plunger chamber (321) and is used for changing the volume in plunger chamber (321), is provided with the drain channel with plunger chamber (321) intercommunication on the casing, is provided with out liquid check valve (36) in the drain channel, its characterized in that: the plunger (5) comprises a solid section for enabling the plunger cavity (321) and the oil cavity not to be communicated, a liquid inlet channel is arranged on the shell, a liquid inlet of the liquid inlet channel is communicated with the oil cavity, a liquid outlet of the liquid inlet channel is communicated with the plunger cavity (321), and a liquid inlet one-way valve (35) is arranged in the liquid inlet channel.

2. The swash plate plunger type hydraulic pump according to claim 1, wherein: the shell is provided with a one-way valve mounting hole (324) and an oil suction hole communicated with the oil cavity, the oil suction hole forms an inlet of the liquid inlet channel, the one-way valve mounting hole (324) is arranged towards the outer side of the shell, and a plugging piece is arranged in the one-way valve mounting hole (324).

3. The swash plate plunger type hydraulic pump according to claim 2, wherein: the plugging piece is provided with an operation hole extending to the inner side of the plugging piece.

4. A swash plate plunger type hydraulic pump according to claim 2 or 3, wherein: the shell is provided with a pipe body structure protruding relative to the surface of the shell, and the check valve mounting hole (324) is arranged in the pipe body structure.

5. The swash plate plunger type hydraulic pump according to claim 4, wherein: at least four pipe structures are uniformly arranged on the shell, the number of the pipe structures is the same as that of the plunger cavities (321), the pipe structures correspond to that of the plunger cavities one by one, and the axes of the pipe structures are tangent lines of the same circle.

6. A swash plate plunger type hydraulic pump according to any one of claims 1 to 3, wherein: the swash plate plunger type hydraulic pump includes a shoe including a shoe return body (22) and a shoe support body (21) which are engaged by screw, and a ball socket for receiving an end portion of the plunger (5) is formed between the shoe return body (22) and the shoe support body (21).

7. The swash plate plunger type hydraulic pump according to claim 6, wherein: and anti-loosening structures for preventing the sliding shoe return body (22) and the sliding shoe support body (21) from loosening are arranged on the sliding shoe return body (22) and the sliding shoe support body (21).

8. The swash plate plunger type hydraulic pump according to claim 7, wherein: the sliding shoe return body (22) is provided with a circumferential array rotation stopping groove (221), the sliding shoe support body (21) is provided with a pin hole, a pin is arranged in the pin hole, and the pin is matched with the rotation stopping groove (221) to stop rotation.

9. A swash plate plunger type hydraulic pump according to any one of claims 1 to 3, wherein: the swash plate plunger type hydraulic pump further comprises a main shaft, a sliding shoe and a return disc (4), wherein a threaded hole is formed in the end face of the main shaft, the return disc (4) and the sliding shoe are limited through a fixing bolt assembled in the threaded hole, the fixing bolt penetrates through the return disc (4) to be in threaded fit with the threaded hole, and the bolt head of the fixing bolt is used for being in stop fit with the return disc (4).

10. A swash plate plunger type hydraulic pump according to any one of claims 1 to 3, wherein: the swash plate plunger type hydraulic pump further comprises a main shaft and a sliding shoe, wherein the main shaft comprises a main shaft body (11) and a wear-resistant disc (12) arranged on the end face of the main shaft body (11), and the wear-resistant disc (12) is in sliding contact fit with the sliding shoe.