CN115929582A - Swash plate type axial plunger pump - Google Patents

Abstract

The invention relates to a swash plate type axial plunger pump, wherein an oil suction groove and an oil suction window are formed on a swash plate of the axial plunger pump, the oil suction window is communicated to the oil suction groove, the oil suction window can suck oil from a shell, an oil suction hole is formed on a thrust plate, and when oil is sucked, a plunger cavity sucks oil from the shell through a slipper center hole, the oil suction window and the oil suction groove; the central hole of the plunger or the sliding shoe is provided with a one-way valve, when the one-way valve is in an open state, the head part of the one-way valve core is separated from the matching surface, and oil enters the plunger cavity through an oil absorption window, an oil absorption groove, an oil absorption hole, the central hole of the sliding shoe, and a gap between the head part of the one-way valve core and the matching surface in sequence; when the check valve is in a closed state, the head of the check valve core is tightly abutted against a matching surface, and a path of oil entering a central hole of the plunger from the central hole of the sliding shoe is blocked. According to the invention, the self-priming upper limit of the rotation speed of the plunger pump is improved according to the actual working condition, and the cavitation erosion prevention effect can be achieved without connecting oil supplementing pumps in series or in parallel, so that the structure is compact; the energy-saving and high-efficiency operation is realized under the low-speed working condition.

Description

Swash plate type axial plunger pump

Technical Field

The invention relates to the technical field of hydraulic elements, in particular to a high-rotating-speed cavitation-resistant swash plate type axial plunger pump.

Background

In the fields of machine tools, metallurgy, mines, engineering machinery and the like, a swash plate type axial plunger pump (hereinafter referred to as a plunger pump) is widely applied to hydraulic transmission systems of various machines, has the characteristics of wide and high working pressure range, high efficiency, compact structure, small volume, light weight, high power density and the like, and is particularly suitable for high-power hydraulic transmission systems. The plunger pump is divided into a quantitative plunger pump and a variable plunger pump, the displacement of the variable plunger pump is adjustable, the output flow range is large, and the application is wider.

When the plunger pump works under the working condition of high rotating speed, the suction flow is insufficient due to the limitation of the flow area of the oil suction flow passage such as the oil suction port, the waist-shaped hole of the cylinder body and the like, the pressure of the oil suction flow passage is lower than the saturated vapor pressure of hydraulic oil to generate cavitation, the service life of the plunger pump, the actual flow of the oil and the outlet pressure are greatly shortened, and the efficiency is greatly reduced.

In order to meet the working requirements of the system in the current market, the plunger pump is mainly used for preventing air suction by adding an oil supplementing pump at an oil inlet. According to the working principle of an oil supplementing pump, a centrifugal oil supplementing pump and a positive displacement oil supplementing pump are adopted, and the structure is divided as follows: there are closed vane pump, single-end vane pump, radial vane pump, gear pump, vane pump, plunger pump and screw pump. According to the using system, the centrifugal oil supplementing pump is selected for the open system main pump, and the positive displacement oil supplementing pump is selected for the closed system main pump. The other proposal is that the oil supplementing pump and the end cover are integrated into a component, and the power source is the main shaft of the main pump. However, the oil replenishing pumps in various forms are driven in a manner that splines are arranged on rotors, the splines are fixedly connected with a main pump main shaft or the splines on a coupling sleeve, and the rotors of the oil replenishing pumps are dragged to rotate by the main shaft to realize pressure boosting and oil replenishing. The oil supplementing pump is connected in series with the oil inlet, so that the pressure of an oil suction cavity of the main pump is improved, the risk of air suction of the pump during high-speed work is reduced, the cavitation phenomenon is effectively avoided, and the service life of the main pump is prolonged. The scheme of oil compensation by using the oil leakage pressure in the shell is also provided, and the flow is compensated by connecting the oil suction port and the shell by using a one-way valve. Avoid cavitation erosion phenomenon and prolong service life.

However, the prior art has the following disadvantages: the existing main scheme is a series oil supplementing pump, the volume and the weight of the plunger pump are increased in the form, and the structure is complex; when the plunger pump works under the working condition of low rotating speed in actual work, the self oil absorption capacity meets the requirement (cavitation and cavitation erosion cannot be generated) and pressure boosting and oil supplementing are not needed, and at the moment, the main shaft drags the oil supplementing pump rotor to rotate, so that the power of a main machine is consumed, and energy is wasted. Meanwhile, the mechanical structure of the rotor of the oil supplementing pump is large, and the overall mechanical efficiency is influenced; the scheme that the one-way valve is arranged on the rear shell to communicate oil with the oil suction port with certain pressure in the shell for oil supplement can reduce cavitation to a certain extent, but the oil suction area of the plunger cavity is not changed essentially, so that the suction phenomenon cannot be improved to a great extent, and leaked oil in the shell is connected with the oil suction port, so that the pressure of the oil suction port cannot be effectively improved. The cavitation erosion prevention effect is limited.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a swash plate type axial plunger pump which can improve the self-absorption upper limit of the rotation speed of the plunger pump according to the actual working condition, change the traditional oil absorption mode, achieve the cavitation-resistant effect without a series or parallel oil supplementing pump and has compact structure; the energy-saving and high-efficiency operation is realized under the low-speed working condition.

The swash plate type axial plunger pump comprises a rotor assembly, a plurality of plunger piston shoe assemblies and a swash plate assembly which are rotationally configured, wherein the plunger piston shoe assemblies are assembled between the rotor assembly and the swash plate assembly and work under the guiding action of the swash plate assembly, the swash plate assembly comprises a swash plate and a thrust plate which are assembled with each other, an oil suction groove and an oil suction window are formed in the swash plate, the oil suction window penetrates through the oil suction groove, an oil suction hole is formed in the thrust plate, and oil is sucked through the oil suction window, the oil suction groove and the oil suction hole in the process that the corresponding piston shoes slide along the oil suction hole; the plunger piston shoe assembly comprises a plunger, a piston shoe and a one-way valve, wherein central holes are formed in the plunger and the piston shoe, the one-way valve comprises a one-way valve element and a one-way valve plug, an axial damping hole is formed in the one-way valve element, an axial central hole is formed in the one-way valve plug, the one-way valve plug is fixedly assembled in the central hole of the plunger, an axial oil channel is arranged on the one-way valve plug or between the one-way valve plug and the wall of the central hole of the plunger, the one-way valve element comprises a head part and a guide post which are connected, the wall surface of the central hole of the plunger comprises a matching surface which can be tightly abutted against the outer peripheral surface of the head part of the one-way valve element, the guide post can be movably inserted into the central hole of the one-way valve plug, and the head part of the one-way valve element faces the matching surface; the one-way valve at least has an opening state and a closing state, when in the opening state, the head part of the one-way valve core is separated from the matching surface, and oil enters through the oil absorption window, the oil absorption groove, the oil absorption hole, the center hole of the sliding shoe, the space between the head part of the one-way valve core and the matching surface and the oil passage in sequence; when the valve is in a closed state, the head of the one-way valve core is abutted against the matching surface, and a path of oil entering the central hole of the plunger from the central hole of the sliding shoe is blocked.

Optionally, after the thrust plate is assembled with the swash plate, a projection of the oil suction hole on the swash plate coincides with the oil suction groove.

Optionally, when the swash plate swing angle is maximum, the sliding shoe forms a first sliding path when sliding on the thrust plate; when the swing angle of the swash plate is minimum, the sliding shoe forms a second sliding path when sliding on the thrust plate; a part of the first sliding path and a part of the second sliding path both fall in the oil suction hole.

Optionally, the oil suction hole extends along a circular arc line.

Optionally, the oil suction hole extends along an elliptical arc.

Optionally, the one-way valve plug is threadedly fitted in the central bore of the plunger.

Optionally, the check valve plug is formed by cutting two parallel surfaces parallel to the axis of the cylinder, and the two parallel surfaces are centrosymmetric along the axis of the central hole of the check valve plug.

Optionally, the head of the one-way valve core is conical, and the matching surface is a matching conical surface.

Optionally, the head of the check valve core is spherical, and the matching surface is a matched spherical surface.

Optionally, the check valve plug is fixedly assembled in a central hole of the sliding shoe, and a wall surface of the central hole of the sliding shoe includes a matching surface capable of abutting against an outer peripheral surface of the head of the check valve element.

Compared with the prior art, the technical scheme of the invention at least has the following beneficial effects:

1. the self-priming rotation speed upper limit of the plunger pump can be improved according to the actual working condition, the traditional oil suction mode is changed, and when the plunger pump works under the working condition of high rotation speed, the cavitation erosion prevention effect can be achieved without connecting oil replenishing pumps in series or in parallel, so that the pump structure is tighter; the energy is saved under the low-speed working condition, and the efficiency of the pump is improved;

2. the piston shoe pull-off force is reduced during oil absorption, the risk of pull-off of the piston shoe of the plunger at high rotating speed is reduced, and the service life of the pump is prolonged;

3. the contact area between the oil suction side sliding shoe and the thrust plate is reduced, and meanwhile, the bottom surface of the sliding shoe is filled with shell oil, so that the mechanical efficiency is improved compared with a structure that the oil suction side sliding shoe is tightly attached to the thrust plate.

Drawings

FIG. 1 is a schematic structural view of a rotor assembly, a plunger shoe assembly and a swash plate assembly in a swash plate type axial piston pump of the present invention;

FIG. 2 is a schematic structural view of a plunger shoe assembly in the swash plate axial plunger pump of the present invention;

FIG. 3 is a schematic diagram of a swash plate axial plunger pump oil path line of the present invention;

FIG. 4 is a schematic view of the construction of a swash plate in the swash plate type axial piston pump of the present invention;

FIG. 5 is a schematic view of the thrust plate in the swash plate axial plunger pump of the present invention;

FIG. 6 is a schematic view of the check valve in the swash plate type axial plunger pump of the present invention;

fig. 7 is a schematic view of a check valve in a swash plate type axial plunger pump of the present invention in a closed state.

In the drawings: the hydraulic cylinder comprises a cylinder body 1, a plunger 2, a one-way valve core 3, a one-way valve plug 4, a sliding shoe 5, a swash plate 6, a spherical hinge 7, a thrust plate 8, a return plate 9 and a compression spring 10.

Detailed Description

Exemplary embodiments of the present invention are described below with reference to the accompanying drawings, in which various details of embodiments of the invention are included to assist understanding, and which are to be considered as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. Also, descriptions of well-known functions and constructions are omitted in the following description for clarity and conciseness.

As shown in fig. 1 to 7, the swash plate type axial plunger pump of the present embodiment includes a rotor assembly, a plurality of plunger shoe assemblies, and a swash plate assembly, which are rotatably disposed, wherein the plunger shoe assemblies are assembled between the rotor assembly and the swash plate assembly and operate under the guiding action of the swash plate assembly, the swash plate assembly includes a swash plate 6 and a thrust plate 8, which are assembled with each other, an oil suction groove and an oil suction window are formed on the swash plate 6, the oil suction window penetrates through the oil suction groove, an oil suction hole is formed on the thrust plate 8, and oil is sucked through the oil suction window, the oil suction groove, and the oil suction hole in the process that the corresponding shoe 5 slides along the oil suction hole; the plunger piston shoe component comprises a plunger 2, a piston shoe 5 and a one-way valve, wherein the plunger 2 and the piston shoe 5 are respectively provided with a central hole, the one-way valve comprises a one-way valve core 3 and a one-way valve plug 4, the one-way valve core 3 is provided with an axial damping hole, the one-way valve plug 4 is provided with an axial central hole, the one-way valve plug 4 is fixedly assembled in the central hole of the plunger 2, an axial oil channel is configured on the one-way valve plug 4 or between the one-way valve plug 4 and the central hole wall of the plunger 2, the one-way valve core 3 comprises a head and a guide post which are connected, the central hole wall of the plunger 2 comprises a matching surface which can be tightly abutted against the outer peripheral surface of the head of the one-way valve core 3, the guide post can be movably inserted into the central hole of the one-way valve plug 4, and the head of the one-way valve core 3 faces the matching surface; the one-way valve at least has an opening state and a closing state, when in the opening state, the head part of the one-way valve core 3 is separated from the matching surface, and oil enters through the oil absorption window, the oil absorption groove, the oil absorption hole, the central hole of the sliding shoe 5, the space between the head part of the one-way valve core 3 and the matching surface and the oil passage in sequence; when the valve is closed, the head of the one-way valve core 3 is pressed against the matching surface, and the path of oil entering the central hole of the plunger 2 from the central hole of the sliding shoe 5 is blocked.

After the thrust plate 8 and the swash plate 6 are assembled, the projection of the oil suction hole on the swash plate 6 is superposed with the oil suction groove; when the swing angle of the swash plate 6 is maximum, the sliding shoe 5 forms a first sliding path when sliding on the thrust plate 8; when the swing angle of the swash plate 6 is minimum, the sliding shoe 5 forms a second sliding path when sliding on the thrust plate 8; part of the first sliding path and part of the second sliding path are both arranged in the oil suction hole, the check valve plug 4 is formed by cutting two parallel surfaces parallel to the axial lead of a cylinder, the two parallel surfaces are symmetrical along the axial lead of a central hole of the check valve plug 4, namely, an oil passage is formed between a cut-off gap of the two parallel surfaces and the wall of the central hole of the plunger 2, and when the check valve is in an open state, oil passes through the oil passages on the two sides.

In the embodiment, the oil suction hole is designed to extend along an arc line, the head of the one-way valve core 3 is conical, the matching surface is a matched conical surface, and the one-way valve plug 4 is assembled in the central hole of the plunger 2 by threads.

In some embodiments, the oil suction hole can be designed to extend along an elliptical arc.

In some embodiments, the head of the check valve core 3 may be designed to be spherical, and the matching surface is a matching spherical surface.

In other embodiments, it may be designed that the check valve is disposed in the central air of the sliding shoe 5, that is, the check valve plug 4 is fixedly fitted in the central hole of the sliding shoe 5, the wall surface of the central hole of the sliding shoe 5 includes a mating surface capable of abutting against the outer peripheral surface of the head portion of the check valve element 3, and other structures and operation principles are the same as those of the above-mentioned form in which the check valve is disposed in the plunger 2.

The cylinder body 1 is connected with a main shaft of a pump (not shown in the figure) through a spline, the plunger 2 is connected with the cylinder body 1 through a plunger hole of the cylinder body 1, and the plunger 2 can reciprocate in the plunger hole of the cylinder body 1; the sliding shoe 5 is hinged with the plunger 2 through a ball head, and the sliding shoe 5 can rotate around the ball head of the plunger 2; meanwhile, the sliding shoe 5 is pressed on the thrust plate 8 by the return disc 9, the sliding shoe 5 can slide on the thrust plate 8, when the sliding shoe 5 slides, the return disc 9 rotates around the spherical surface of the spherical hinge 7, the spherical hinge 7 and the return disc 9 are pressed by the cylinder body 1 through the pressing spring 10, and the cylinder body 1 is pressed by the shell and a port plate (not shown in the figure); the one-way valve plug 4 is connected with the thread of the inner cavity of the plunger 2 through the thread, as shown in figure 2, the one-way valve core 3 is inserted into the central hole of the one-way valve plug 44 through the tail cylinder dd1 and is combined with the tapered hole of the inner cavity A1 of the plunger 2 to form a one-way valve; the diameters of central holes of the plunger 2 and the sliding shoe 5 are dz2, so that the damping effect is not achieved, and a certain amount of oil can be sucked from the shell by the plunger cavity when needed.

When the plunger pump works, the cylinder body 1 rotates towards the direction shown in the attached drawing 1, the plunger 2 is pressed on the thrust plate 8 by the return disc 9 and is pulled out of a plunger cavity of the cylinder body 1, the pressure of the plunger cavity is reduced, and oil is sucked. When the rotating speed of the cylinder body 1 is high, the speed of sucking the oil in the plunger cavity through the kidney-shaped hole of the cylinder body 1 is increased, the pressure in the plunger cavity is reduced according to the Bernoulli equation because the pressure of the oil suction port is constant, and when the pressure of the oil in the plunger cavity is close to the saturated steam pressure of the hydraulic oil, the one-way valve is opened, and the hydraulic oil flows into the plunger cavity as shown in the attached figure 3. The hydraulic oil sucked through the check valve is sucked into the plunger chamber through the kidney grooves A2 and A3, A4 of the swash plate 6 and the thrust plate 8 (as shown in fig. 4, the kidney grooves A3 and A4 of the swash plate 6 and the thrust plate 8 coincide). At this time, the plunger cavity of the cylinder body 11 is communicated with leakage oil with certain pressure in the shell, and the leakage oil flows into the plunger cavity through the central hole of the plunger 2. At this time, the plunger cavity can suck hydraulic oil with certain pressure from the shell, and meanwhile, the flow of the kidney-shaped hole of the cylinder body 11 is not occupied, and according to a formula:

Q=v1*A1+v2*A2

wherein: q is total flow of plunger chamber intake; v 1-plunger kidney-shaped hole flow rate; a1, plunger waist-shaped hole flow area;

v 2-flow rate of central hole of plunger; a2, the flow area of a central hole of the plunger;

the larger the flow area of the central hole dz2 of the plunger 2 is, the slower the flow velocity v1 of the hydraulic oil at the waist-shaped hole of the cylinder 1 is. According to the Bernoulli equation, the slower the hydraulic oil flow rate, the less the pressure in the plunger cavity is reduced, thereby achieving the function of preventing cavitation.

When the plunger piston shoe assembly rotates to a high-pressure area, the plunger piston shoe assembly is pushed back to the plunger cavity by the swash plate 6, the pressure in the plunger cavity rises, the one-way valve is closed because the pressure of the plunger cavity is higher than the pressure of the shell, and high-pressure oil formed in the plunger cavity flows to the bottom surface of the piston shoe 5 through the damping hole in the center of the one-way valve core 3 to form support.

As shown in fig. 4 and 5, an oil suction window A2 is arranged on the oil suction side of the swash plate 6, the oil suction window A2 is communicated with the kidney-shaped groove A3, the thrust plate 8 is provided with a kidney-shaped groove A4 which is the same as the swash plate 6, the kidney-shaped grooves A3 and A4 are ensured to be overlapped by a limiting device during installation, and the kidney-shaped groove can cover the track of the slipper 5 when the inclination angle of the swash plate 6 is maximum and minimum so as to ensure that the plunger cavity is communicated with the shell by leakage oil when necessary.

As shown in figure 6, the one-way valve core 3 consists of a cone A6 at the top and a cylinder A7 at the tail, the one-way valve core 4 is a plug with a central hole, when the thread of the one-way valve core 4 is connected with the plunger 2, a gap B1 shown in figure 2 is formed to ensure the circulation of hydraulic oil, the central hole is matched with the cylinder A7 at the tail of the one-way valve core 3 to ensure that the direction of the one-way valve core 3 is unchanged, the cone angle of the cone at the top of the one-way valve core 3 is the same as that of the cone in the plunger hole, when the plunger cavity is in high pressure, the hydraulic oil is ensured not to circulate, and the damping hole at the center of the one-way valve core 3 ensures that the high-pressure oil in the plunger cavity flows to the bottom surface of the sliding shoe 5 to form a support through the damping hole. When the plunger piston shoe 5 sideslips from the high pressure side to the low pressure side, the check valve is in a closed state, as shown in figure 7, the axial area of a cone A6 at the top of the check valve core 3 and an effective contact surface B4 of leakage oil is smaller than the sum of the areas of effective contact surfaces B2 and C3 of hydraulic oil in the plunger cavity, so that the pressure difference between the plunger cavity pressure and the saturated steam pressure is larger when the displacement is small, the pressure difference with the leakage oil is relatively smaller, the check valve core 3 is not opened, and the phenomenon that when the oil in the shell is not leaked enough, the oil absorption state is kept to cause insufficient leakage, and the pump generates heat is avoided.

According to the invention, the flow distribution windows are arranged on the swash plate 6 and the thrust plate 8, and the one-way valve with the damping hole is arranged on the plunger 2, so that leakage oil with a certain pressure can be led back to the plunger cavity on the oil suction side when the pressure of the plunger cavity is close to the saturated vapor pressure, the pressure of the plunger cavity is increased, and cavitation is avoided. And meanwhile, the static pressure support of the oil pressing side is not influenced.

Compared with the prior art, the swash plate type axial plunger pump has the following advantages:

1. the self-priming rotation speed upper limit of the plunger pump can be improved according to the actual working condition, the traditional oil suction mode is changed, and when the plunger pump works under the working condition of high rotation speed, the cavitation erosion prevention effect can be achieved without connecting oil replenishing pumps in series or in parallel, so that the pump structure is tighter; the energy is saved under the low-speed working condition, and the efficiency of the pump is improved;

2. the piston shoe pull-off force is reduced during oil absorption, the risk of pull-off of the piston shoe of the plunger at high rotating speed is reduced, and the service life of the pump is prolonged;

3. the contact area between the oil suction side sliding shoe and the thrust plate is reduced, and meanwhile, the bottom surface of the sliding shoe is filled with shell oil, so that the mechanical efficiency is improved compared with a structure that the common oil suction side sliding shoe is tightly attached to the thrust plate.

The above detailed description should not be construed as limiting the scope of the invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions can occur, depending on design requirements and other factors. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A swash plate type axial piston pump including a rotor assembly, a plurality of piston shoes and a swash plate assembly which are rotatably disposed, the plurality of piston shoes being fitted between the rotor assembly and the swash plate assembly and operating under a guide action of the swash plate assembly,

the sliding shoe type oil suction device comprises a swash plate assembly and a thrust plate assembly, wherein the swash plate assembly comprises a swash plate and the thrust plate which are assembled with each other, an oil suction groove and an oil suction window are formed in the swash plate, the oil suction window is communicated to the oil suction groove, an oil suction hole is formed in the thrust plate, and oil is sucked through the oil suction window, the oil suction groove and the oil suction hole in the process that the corresponding sliding shoe slides along the oil suction hole;

the plunger piston shoe assembly comprises a plunger, a piston shoe and a one-way valve, wherein central holes are formed in the plunger and the piston shoe, the one-way valve comprises a one-way valve element and a one-way valve plug, an axial damping hole is formed in the one-way valve element, an axial central hole is formed in the one-way valve plug, the one-way valve plug is fixedly assembled in the central hole of the plunger, an axial oil channel is arranged on the one-way valve plug or between the one-way valve plug and the wall of the central hole of the plunger, the one-way valve element comprises a head part and a guide post which are connected, the wall surface of the central hole of the plunger comprises a matching surface which can be tightly abutted against the outer peripheral surface of the head part of the one-way valve element, the guide post can be movably inserted into the central hole of the one-way valve plug, and the head part of the one-way valve element faces the matching surface;

the one-way valve at least has an opening state and a closing state, when in the opening state, the head part of the one-way valve core is separated from the matching surface, and oil enters through the oil absorption window, the oil absorption groove, the oil absorption hole, the center hole of the sliding shoe, the space between the head part of the one-way valve core and the matching surface and the oil passage in sequence; when the valve is in a closed state, the head of the one-way valve core is tightly propped against the matching surface, and a path for oil to enter the central hole of the plunger from the central hole of the sliding shoe is blocked.

2. The swash plate type axial piston pump as claimed in claim 1, wherein the projection of the oil suction hole on the swash plate coincides with the oil suction groove after the thrust plate is assembled with the swash plate.

3. The swash plate type axial piston pump as claimed in claim 2, wherein the shoe forms a first sliding path when sliding on the thrust plate at a maximum swash angle; when the swing angle of the swash plate is minimum, the sliding shoe forms a second sliding path when sliding on the thrust plate; a part of the first sliding path and a part of the second sliding path both fall in the oil suction hole.

4. The swash plate type axial plunger pump according to claim 3, wherein the oil suction hole is extended along a circular arc line.

5. The swash plate type axial plunger pump according to claim 3, wherein the oil suction hole is extended along an elliptical arc.

6. The swash plate axial plunger pump of claim 1, wherein the check valve is threadably mounted in the central bore of the plunger.

7. The swash plate type axial plunger pump according to claim 1, wherein the check valve block is a cylinder cut by two parallel faces parallel to the axis, and the two parallel faces are symmetrical with respect to the center of the axis of the center hole of the check valve block.

8. The swash plate axial plunger pump of claim 1 wherein the head of the check valve spool is tapered and the mating surfaces are mating tapered surfaces.

9. The swash plate axial plunger pump of claim 1 wherein the head of the check valve spool is spherical and the mating surfaces are mating spherical surfaces.

10. The swash plate type axial plunger pump according to claim 1, wherein the check valve plug is fixedly fitted in a center hole of the shoe, and a wall surface of the center hole of the shoe includes a mating surface capable of abutting against an outer peripheral surface of the head portion of the check valve body.

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