An axial piston pump

Abstract

The present application relates to a kind of axial plunger pumps.The technical problems of high machining precision requirement, high machining cost, short service life and high maintenance cost of existing axial plunger pump are solved.The axial plunger pump of the present application comprises a pump cover shell, a pump cavity shell, a flow distribution disc, a rotor, an oil suction nozzle and an oil discharge nozzle;the flow distribution disc is provided with an oil suction flow channel and an oil discharge flow channel;the pump cover shell is provided with an oil suction hole and an oil discharge hole;the oil suction flow channel comprises a cylindrical oil suction hole, a first transition hole and a first rotor connecting hole;the small end of the first transition hole is communicated with the cylindrical oil suction hole, and the large end is communicated with the first rotor connecting hole;the oil discharge flow channel comprises a cylindrical oil discharge hole, a second transition hole and a second rotor connecting hole;the cylindrical oil discharge hole, the second transition hole and the second rotor connecting hole are respectively the same structure as the cylindrical oil suction hole, the first transition hole and the first rotor connecting hole;the cylindrical oil suction hole is sealingly connected with the oil suction hole through the oil suction nozzle;the cylindrical oil discharge hole is sealingly connected with the oil discharge hole through the oil discharge nozzle.

Description

TECHNICAL FIELD

[0001] The present application relates to an axial piston pump. BACKGROUND

[0002] The axial piston pump has the advantages of compact structure, small radial size and rotary inertia, and high volumetric efficiency, and can work at high speed and high pressure, so it is widely used in hydraulic systems of mechanical equipment with high pressure, large flow and flow adjustment, and as the most common power element of the hydraulic system, its performance is very important for the working performance of the hydraulic system.

[0003] The valve plate is one of the core components of the axial piston pump, and the performance parameters of the valve plate have a great influence on the flow characteristics and service life of the axial piston pump. During the working process of the axial piston pump, on the one hand, the valve plate and the rotor form a valve friction pair, and the relative sliding speed between them is high and the contact pressure is large; on the other hand, the valve plate and the pump cover form a face-to-face seal to reduce the leakage during the operation of the piston pump.

[0004] The existing axial piston pump requires that the working surfaces of the valve plate in contact with the rotor and the pump cover and the matching surfaces have very high machining precision (the flatness of the high-pressure piston pump even reaches 5 thousandths, and the roughness is not higher than Ra0.4) in order to ensure the working performance and efficiency of the axial piston pump, because the smoothness and fit of the contact surfaces of the valve plate, the rotor and the pump cover will directly affect the volumetric efficiency of the axial piston pump and the service life of the piston pump. However, the superfinishing of the working surfaces of the valve plate and the matching surfaces requires high machining cost, and if the machining precision does not meet the requirements, the service life of the valve plate will be greatly shortened, and high maintenance cost will also be generated. With the development of hydraulic technology, the requirements for the service life and cost of hydraulic elements are getting higher and higher, and the existing structure of the axial piston pump cannot meet the requirements. SUMMARY

[0005] The present application aims to solve the technical problems of high machining precision requirement, high machining cost, short service life and high maintenance cost of the valve plate structure of the existing axial piston pump, and to provide an axial piston pump.

[0006] The technical solution of the present application is:

[0007] An axial piston pump, comprising a pump cover shell, a pump cavity shell connected with the pump cover shell, a valve plate arranged between the pump cover shell and the pump cavity shell, and a rotor arranged in the pump cavity shell and in contact with the valve plate; one end of the rotor is provided with a rotor hole, and the other end is provided with a piston assembly communicated with the rotor hole; one side of the valve plate in contact with the pump cover shell is a B side, and the other side in contact with the rotor is an A side; the valve plate is provided with an oil suction flow channel and an oil discharge flow channel; the pump cover shell is provided with an oil suction hole and an oil discharge hole;

[0008] The speciality is:

[0009] Further comprising oil suction nozzle and oil discharge nozzle arranged on the distribution disc;

[0010] The oil suction flow channel comprises a cylindrical oil suction hole opening on the B face, a first transition hole and a first rotor connecting hole opening on the A face; the first rotor connecting hole is an arc long circular hole; the first transition hole is an arc long circular hole with a tapered structure, with a small end communicating with the cylindrical oil suction hole and a large end communicating with the first rotor connecting hole;

[0011] The oil discharge flow channel comprises a cylindrical oil discharge hole opening on the B face, a second transition hole and a second rotor connecting hole opening on the A face; the cylindrical oil discharge hole, the second transition hole and the second rotor connecting hole are respectively identical in structure with the cylindrical oil suction hole, the first transition hole and the first rotor connecting hole, and are symmetrically arranged;

[0012] The cylindrical oil suction hole is in sealed connection with the oil suction hole on the pump cover shell through the oil suction nozzle;

[0013] The cylindrical oil discharge hole is in sealed connection with the oil discharge hole on the pump cover shell through the oil discharge nozzle;

[0014] The width and radial position of the first rotor connecting hole are adapted to the size and radial position of the rotor hole of the rotor;

[0015] The central angle of the arc long circular hole of the first rotor connecting hole is 140°≤γ≤160°;

[0016] The included angle between the tapered section of the first transition hole and the sidewall of the first rotor connecting hole is 90°<α<170°;

[0017] The perpendicularity of the oil suction nozzle and the oil discharge nozzle to the A face is 0.003-0.006.

[0018] Further, the γ is 150°; the α is 135°; and the perpendicularity of the oil suction nozzle and the oil discharge nozzle to the A face is 0.005.

[0019] Further, two sealing protection rings are further arranged between the oil suction nozzle and the pump cover shell and between the oil discharge nozzle and the pump cover shell respectively; a sealing groove is arranged on the outer sidewall of the oil suction nozzle and the oil discharge nozzle along the circumference respectively; and the two sealing protection rings are respectively sleeved in the sealing grooves of the oil suction nozzle and the oil discharge nozzle.

[0020] Further, a non-metallic sealing material is further arranged in the sealing groove.

[0021] Further, the oil suction nozzle and the oil discharge nozzle are in an integral structure with the distribution disc.

[0022] Further, two pin holes are further included; the two pin holes are symmetrically arranged on the B face of the distribution disc, and are used for inserting pins to connect the distribution disc and the pump cover shell.

[0023] Advantages of the present application:

[0024] 1. The axial piston pump changes the traditional face-face sealing structure, connects the distribution disc with the oil suction hole and the oil discharge hole of the pump cover shell through the oil suction nozzle and the oil discharge nozzle, improves the sealing performance of the distribution disc and the pump cover shell, and reduces the machining precision of the distribution disc and the maintenance cost.

[0025] 2. The axial piston pump designs the central angle of the first rotor connecting hole and the second rotor connecting hole as 140 DEG <= gamma <= 160 DEG, prevents the pressure in the rotor hole from being blocked when the piston assembly moves from the oil suction area to the oil discharge area, and prevents cavitation from occurring in the rotor hole; meanwhile, the gamma angle cannot be too large, and the large gamma angle increases the volume loss when the piston assembly moves from the oil suction area to the oil discharge area, and reduces the performance of the piston pump.

[0026] 3. The axial piston pump designs the included angle between the tapered section of the first transition hole and the sidewall of the first rotor connecting hole as 90 DEG < alpha < 170 DEG, the alpha angle is less than 90 DEG, the flow area in the distribution disc changes greatly, and the flow loss in the distribution disc is increased; when the alpha angle is greater than 170 DEG, the local strength of the distribution disc cannot meet the requirements or the axial size of the distribution disc is large.

[0027] 4. The axial piston pump is provided with a sealing protection ring and extruded non-metallic sealing material outside the oil suction nozzle and the oil discharge nozzle to form a double-layer sealing structure, the oil suction hole and the oil discharge hole on the pump cover shell are extruded by the non-metallic sealing material outside the oil suction nozzle and the oil discharge nozzle, the sealing effect is achieved, and the leakage between the distribution disc and the pump cover shell during the operation of the piston pump is prevented.

[0028] 5. The axial piston pump changes the contact mode between the distribution disc and the pump cover shell by designing the structure, reduces the machining precision and the machining cost of the distribution disc, and makes the later maintenance simpler and more convenient, meets the actual use requirement, improves the overall performance of the axial piston pump, and prolongs the service life. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a structure schematic view of the embodiment of the axial piston pump.

[0030] Figure 2 It is a structure schematic view of the embodiment of the axial piston pump. Figure 1 It is an enlarged view of F in the figure.

[0031] Figure 3 It is an enlarged view of D in the figure. Figure 2 ​

[0032] Figure 4 For Figure 2 Enlarged view at

[0033] Figure 5 For the structure schematic diagram of the valve plate of an embodiment of the axial piston pump of the present application;

[0034] Figure 6 For the structure schematic diagram of the A surface of the valve plate of an embodiment of the axial piston pump of the present application;

[0035] Figure 7 For the structure schematic diagram of the B surface of the valve plate of an embodiment of the axial piston pump of the present application;

[0036] Figure 8 For the sectional view along Figure 6 A-A line;

[0037] Figure 9 For the sectional view along Figure 6 B-B line;

[0038] Figure 10 For Figure 8 the local enlarged view at H.

[0039] The reference signs in the drawings are:

[0040] 1 - valve plate, 3 - transmission shaft, 4 - pump cover shell, 8 - pump cavity shell, 9 - swash plate, 10 - piston assembly, 11 - rotor;

[0041] 111 - first rotor connecting hole, 114 - pin hole, 115 - second rotor connecting hole; 120 - oil suction nozzle, 121 - cylindrical oil suction hole, 122 - non-metallic sealing material, 123 - sealing protection ring; 130 - oil discharge nozzle, 131 - cylindrical oil discharge hole; 41 - oil suction hole, 42 - oil discharge hole; 1101 - rotor hole, 1102 - rotor working surface. DETAILED DESCRIPTION

[0042] The present application will be described in detail below with the aid of the drawings and examples.

[0043] As Figures 1-4As shown, the axial plunger pump of the present application comprises a pump cover shell 4, a pump cavity shell 8 connected with the pump cover shell 4, a distribution disc 1 arranged between the pump cover shell 4 and the pump cavity shell 8, and a rotor 11 arranged in the pump cavity shell 8 and in contact with the distribution disc 1; one end of the rotor 11 is provided with a rotor hole 1101, and the other end is provided with a plunger assembly 10 in communication with the rotor hole 1101; the side of the distribution disc 1 in contact with the pump cover shell 4 is a B side, and the side in contact with the rotor 11 is an A side; the distribution disc 1 is provided with an oil suction flow channel and an oil discharge flow channel; the pump cover shell 4 is provided with an oil suction hole 41 and an oil discharge hole 42; further comprising an oil suction nozzle 120, an oil discharge nozzle 130, two sealing protection rings 123 and a non-metallic sealing material 122. The working principle of the axial plunger pump is as follows: when the motor drives the transmission shaft 3 to rotate, the rotor 11 rotates together with the plunger assembly 10, and the plunger head always keeps away from the swash plate 9, because the swash plate 9 is at a certain angle with the rotor 11, so that when the rotor 11 rotates, the plunger assembly 10 makes reciprocating motion in the rotor 11. Among them, the side of the distribution disc 1 in contact with the pump cover shell 4 is a B side, and the side in contact with the rotor 11 is an A side, the A side of the distribution disc 1 forms a face-to-face cooperation with a rotor working surface 1102, and the rotor working surface 1102 is provided with a rotor hole 1101. The distribution disc 1 is provided with an oil suction flow channel and an oil discharge flow channel, when the axial plunger pump works, when the plunger assembly 10 rotates from the lowest point to the highest point, i.e. to the uppermost position of the plunger, the volume of the rotor hole 1101 gradually increases, and the liquid enters the rotor hole 1101 from the oil suction hole 41 of the pump cover shell 4 through the oil suction nozzle 120 and the oil suction flow channel of the distribution disc 1; when the plunger assembly 10 rotates from the highest point to the lowest point, the volume of the rotor hole 1101 gradually decreases, and the liquid in the rotor hole 1101 enters the oil discharge hole 42 of the pump cover shell 4 through the oil discharge flow channel and the oil discharge nozzle 130.

[0044] The oil suction flow channel in the present application comprises a cylindrical oil suction hole 121 opening on the B side, a first transition hole and a first rotor connecting hole 111 opening on the A side. Figures 5-9As shown, the first rotor connecting hole 111 is an arc-shaped long circular hole; the first transition hole is an arc-shaped long circular hole with a conical structure, the small end of which is in communication with the cylindrical oil suction hole 121, and the large end of which is in communication with the first rotor connecting hole 111; the oil discharge flow channel includes the cylindrical oil discharge hole 131, the second transition hole and the second rotor connecting hole 115 which are opened on the B surface; the cylindrical oil discharge hole 131, the second transition hole and the second rotor connecting hole 115 are respectively the same in structure as the cylindrical oil suction hole 121, the first transition hole and the first rotor connecting hole 111, and are symmetrically arranged. The first rotor connecting hole 111 and the second rotor connecting hole 115 are located between the two sealing bands 113, and the A surface is further provided with a lubricating oil groove 112 which surrounds the outer periphery of the outer sealing band 113. The first rotor connecting hole 111 and the second rotor connecting hole 115 are adapted to the inner and outer diameters of the rotor hole 1101, and work in cooperation, for ensuring the smooth flow of the liquid medium from the rotor hole to the cylindrical oil suction and discharge hole during the operation of the plunger pump, reducing the leakage and energy loss. As shown in FIG. 1, the first rotor connecting hole 111 and the second rotor connecting hole 115 are respectively connected to the first rotor connecting hole 111 and the second rotor connecting hole 115 through the first transition hole and the second transition hole, and the first transition hole and the second transition hole are respectively connected to the cylindrical oil suction hole 121 and the cylindrical oil discharge hole 131 through the cylindrical oil suction hole 121 and the cylindrical oil discharge hole 131. Figure 5As shown, the cylindrical oil suction hole 121 is in sealed connection with the oil suction hole 41 on the pump cover shell 4 through the oil suction nozzle 120, so that the liquid flows from the oil suction hole 41 on the pump cover shell 4 to the oil suction flow channel of the distribution plate 1; the cylindrical oil discharge hole 131 is in sealed connection with the oil discharge hole 42 on the pump cover shell 4 through the oil discharge nozzle 130, so that the liquid flows from the rotor hole to the oil discharge flow channel of the distribution plate 1. The width and radial position of the first rotor connecting hole 111 are matched with the size and radial position of the rotor hole 1101 of the rotor 11, and the two are matched to allow the liquid to flow through. During the operation of the plunger pump, the liquid medium passes through the funnel large end opening of the oil suction flow channel on the distribution plate 1 and the rotor hole on the rotor working surface, so that when the oil is sucked, the liquid medium sucked by the oil suction hole 41 of the pump cover shell 4 reaches the rotor hole, and when the oil is discharged, the high-pressure liquid medium in the rotor hole reaches the oil discharge hole 42 through the oil discharge flow channel. The central angle of the arc-shaped long circular hole of the first rotor connecting hole 111 is 140°≤γ≤160°, and the angle size of γ is also a very key influencing factor. If the angle of γ is too small, the pressure in the rotor hole 1101 will be built up during the movement of the plunger assembly 10 from the oil suction area to the oil discharge area, and cavitation will occur in the rotor hole when the plunger assembly 10 moves to the oil discharge area. If the angle of γ is too large, the volume loss will increase when the plunger assembly 10 moves from the oil suction area to the oil discharge area, and the performance of the plunger pump will be reduced. In the embodiment, γ is preferably 150°. In order to reduce the sudden change of the liquid flow state and reduce the flow loss of the liquid medium in the distribution plate 1, the flow channel in the distribution plate 1 needs to be smoothly transitioned. The included angle between the tapered section of the first transition hole and the sidewall of the first rotor connecting hole 111 is 90°<α<170°. If the angle of α is less than 90°, the cross-sectional area of the flow in the distribution plate 1 will suddenly change, resulting in increased flow loss in the distribution plate. If the angle of α is greater than 170°, the local strength of the distribution plate 1 will not meet the requirements. If the strength meets the requirements, the axial size of the distribution plate will be larger. In the embodiment, α is preferably 135°. At the same time, in order to ensure the normal operation of the axial plunger pump, the A surface of the oil suction nozzle 120 and the oil discharge nozzle 130 should meet the perpendicularity requirement of 0.003-0.006. If the perpendicularity value is too small, the processing difficulty will be doubled, and if the perpendicularity is too large, the leakage will be large, which will affect the performance of the plunger pump. In addition, if the perpendicularity does not meet the requirements, the non-metallic sealing material 122 may be compressed unevenly in the circumferential direction, causing sealing failure, and the rotor 11 and the distribution plate 1 may also be unevenly contacted, causing the gap leakage at the position to increase. In the embodiment, the perpendicularity value is preferably 0.005.

[0045] The main difference between the present application and the traditional distribution plate is that the distribution plate 1 of the present application is in sealed communication with the pump cover shell 4 through the oil suction nozzle 120 and the oil discharge nozzle 130, so that the high-precision face sealing on the side of the distribution plate 1 contacting the pump cover shell 4 is changed to non-metallic material extrusion sealing, that is, the B surface is changed from the original planar contact to the contact through the oil suction nozzle 120 and the oil discharge nozzle 130, which reduces the machining precision of the B surface and improves the sealing between the distribution plate 1 and the pump cover shell 4.Figure 10 As shown, the outer side walls of the oil suction nozzle 120 and the oil discharge nozzle 130 are respectively provided with a sealing groove along the circumference, and two sealing protection rings 123 are respectively sleeved in the sealing grooves of the oil suction nozzle 120 and the oil discharge nozzle 130. In addition, in order to strengthen the sealing and prevent the oil leakage phenomenon, the sealing grooves are also filled with non-metallic sealing materials 122. The outer diameters of the sealing protection rings 123 and the non-metallic sealing materials 122 are greater than the outer diameters of the sealing grooves, that is, the sealing protection rings 123 and the non-metallic sealing materials 122 all protrude out of the sealing grooves, so that when the oil suction nozzle 120 and the oil discharge nozzle 130 are connected with the oil suction hole 41 and the oil discharge hole 42 respectively, the two sealing protection rings 123 and the non-metallic sealing materials 122 are respectively located between the oil suction nozzle 120 and the pump cover shell 4 and between the oil discharge nozzle 130 and the pump cover shell 4, and the sealing protection rings 123 and the non-metallic sealing materials 122 are extruded with the inner walls of the oil suction hole 41 or the oil discharge hole 42, so as to achieve the sealing effect. In order to reduce the surface precision requirement, the processing cost and improve the maintainability, in the embodiment, the oil suction nozzle 120 and the oil discharge nozzle 130 are integrated with the distribution plate 1.

[0046] In order to prevent the distribution plate 1 from rotating along the circumferential direction with the rotor 11 when the axial piston pump is running, causing the non-metallic sealing materials 122 on the oil suction nozzle 120 and the oil discharge nozzle 130 to be compressed in a single direction of the oil suction hole 41 and the oil discharge hole 42 on the pump cover shell 4, resulting in a smaller compression or even no compression in the other direction, and further causing the sealing failure at the place, causing the medium to leak, therefore, two pin holes 114 for positioning are opened on the contact side (that is, the B surface) of the distribution plate 1 and the pump cover shell 4, the two pin holes 114 are arranged symmetrically at 180°, and the pins are inserted to connect the distribution plate 1 and the pump cover shell 4, so as to realize the positioning of the distribution plate 1.

[0047] The axial piston pump provided by the application is a re-designed structure of the existing distribution plate, changes the sealing mode between the distribution plate and the pump cover shell, and changes the face sealing into the extrusion sealing of the non-metallic material. In actual use, the A surface of the distribution plate in the axial piston pump is in face-to-face cooperation with the working surface of the rotor, and the oil suction nozzle 120 and the oil discharge nozzle 130 on the B surface of the distribution plate respectively extend into the oil suction hole 41 and the oil discharge hole 42 on the pump cover shell 4, the inner walls of the oil suction hole 41 and the oil discharge hole 42 on the pump cover shell 4 are extruded with the non-metallic sealing materials on the periphery of the oil suction nozzle 120 and the oil discharge nozzle 130, so as to achieve the sealing effect and ensure that there is no leakage between the distribution plate and the pump cover shell 4 during the running of the axial piston pump.

[0048] The axial plunger pump reduces the high-precision machining requirement of the traditional distribution disc to the B surface and to the shell of the pump cover, and if the non-metallic sealing material 122 is damaged during the use of the axial plunger pump, the axial plunger pump can be replaced on the use site, without the need of special repair equipment and personnel, without the need of being transferred to a specific repair room, and the maintenance difficulty is greatly reduced and the service life of the axial plunger pump is prolonged.

[0049] In summary, the embodiment is sufficient to illustrate that by changing the sealing structure of the traditional axial plunger pump distribution disc and the shell, the machining cost can be reduced without affecting the performance of the axial plunger pump, the later maintenance is simple, the actual use needs are met, the operability is high, and the use value is high.

Claims

1. An axial plunger pump, comprising a pump cover shell (4), a pump cavity shell (8) connected with the pump cover shell (4), a distribution disc (1) arranged between the pump cover shell (4) and the pump cavity shell (8), and a rotor (11) arranged in the pump cavity shell (8) and in contact with the distribution disc (1); one end of the rotor (11) is provided with a rotor hole (1101), and the other end is provided with a plunger assembly (10) in communication with the rotor hole (1101); one side of the distribution disc (1) in contact with the pump cover shell (4) is a B side, and the other side in contact with the rotor (11) is an A side; the distribution disc is provided with an oil suction flow channel and an oil discharge flow channel; the pump cover shell (4) is provided with an oil suction hole (41) and an oil discharge hole (42); Characterized in that: it further comprises an oil suction nozzle (120) and an oil discharge nozzle (130) arranged on the distribution disc (1); the oil suction flow channel comprises a cylindrical oil suction hole (121) opening on the B side, a first transition hole, and a first rotor connecting hole (111) opening on the A side; the first rotor connecting hole (111) is an arc-shaped long circular hole; the first transition hole is an arc-shaped long circular hole with a tapered structure, the small end of which is in communication with the cylindrical oil suction hole (121), and the large end of which is in communication with the first rotor connecting hole (111); the oil discharge flow channel comprises a cylindrical oil discharge hole (131) opening on the B side, a second transition hole, and a second rotor connecting hole (115) opening on the A side; the cylindrical oil discharge hole (131), the second transition hole, and the second rotor connecting hole (115) are respectively the same in structure as the cylindrical oil suction hole (121), the first transition hole, and the first rotor connecting hole (111), and are symmetrically arranged; the cylindrical oil suction hole (121) is in sealed connection with the oil suction hole (41) on the pump cover shell (4) through the oil suction nozzle (120); the cylindrical oil discharge hole (131) is in sealed connection with the oil discharge hole (42) on the pump cover shell (4) through the oil discharge nozzle (130); the width and radial position of the first rotor connecting hole (111) are adapted to the size and radial position of the rotor hole (1101) of the rotor (11); the central angle of the arc-shaped long circular hole of the first rotor connecting hole (111) is 140°≤γ≤160°; the included angle between the tapered section of the first transition hole and the sidewall of the first rotor connecting hole (111) is 90°<α<170°; the perpendicularity of the oil suction nozzle (120) and the oil discharge nozzle (130) to the A side is 0.003-0.

006.

2. The axial plunger pump according to claim 1, characterized in that: γ is 150°; α is 135°; the perpendicularity of the oil suction nozzle (120) and the oil discharge nozzle (130) to the A side is 0.

005.

3. The axial plunger pump according to claim 1 or 2, characterized in that: it further comprises two sealing protection rings (123) arranged between the oil suction nozzle (120) and the pump cover shell (4) and between the oil discharge nozzle (130) and the pump cover shell (4) respectively; the outer sidewalls of the oil suction nozzle (120) and the oil discharge nozzle (130) are respectively provided with sealing grooves along the circumference. The two sealing protection rings (123) are respectively sleeved in the sealing grooves of the oil suction nozzle (120) and the oil discharge nozzle (130).

4. The axial piston pump of claim 3, wherein: Further comprising a non-metallic sealing material (122); The non-metallic sealing material (122) is arranged in the sealing groove.

5. The axial piston pump of claim 4, wherein: The oil suction nozzle (120) and the oil discharge nozzle (130) are in an integrated structure with the distribution plate (1).

6. The axial piston pump of claim 5, wherein: Further comprising two pin holes (114); The two pin holes (114) are symmetrically arranged on the B face of the distribution plate (1) and are used for inserting pins to connect the distribution plate (1) and the pump cover shell (4).

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