Axial piston pump

Abstract

An axial piston pump, comprising a pump casing assembly (3), a base plate and a water inlet / outlet flange (7), wherein the pump casing assembly (3), the base plate and the water inlet / outlet flange (7) enclose an inner cavity for accommodating the other structures of the piston pump; a piston cylinder assembly (2), a piston and piston forced-return assembly (4) and a swash plate assembly (5) are arranged in the inner cavity; a transmission shaft (8) passes through the water inlet / outlet flange (7) and is connected to the piston cylinder assembly (2); the piston and piston forced-return assembly (4) comprises a piston assembly and a forced return mechanism, the piston assembly comprising a ceramic piston (4.1) and a ceramic slipper (4.6), the forced return mechanism comprising a return plate (4.2), a spherical hinge (4.3), a return guide pillar (4.4) and properly pre-compressed springs (4.5), the ceramic slipper (4.6) being connected to the return plate (4.2) and being supported on the swash plate assembly (5), a planar surface of the spherical hinge (4.3) and the return plate (4.2) forming a planar friction pair, a spherical surface of the spherical hinge (4.3) being hinged to a spherical socket (4.4.1) of the return guide pillar (4.4), and the return guide pillar (4.4) being mounted in a return guide sleeve (2.3) of the piston cylinder assembly (2); a plurality of spring holes for mouting the properly pre-compressed springs (4.5) are provided in the surface of the return guide pillar (4.4) opposite the spherical socket (4.4.1); and ends of the properly pre-compressed springs (4.5) extend from the spring holes and abut against the piston cylinder assembly (2). The axial piston pump has a wide application range and long service life.

Description

Axial piston pump TECHNICAL FIELD

[0001] The present application belongs to the technical field of piston pump, and particularly relates to an axial piston pump. BACKGROUND

[0002] The piston pump is an important device of the hydraulic system. It relies on the reciprocating movement of the piston in the cylinder to change the volume of the sealed working cavity to realize water suction and water compression. The piston pump has the advantages of high rated pressure, compact structure, high efficiency and convenient flow regulation.

[0003] The axial piston pump (English name: piston pump) is a piston or plunger reciprocating direction parallel to the center axis of the cylinder. The axial piston pump works by the volume change caused by the reciprocating movement of the plunger parallel to the transmission shaft in the plunger hole. Since the plunger and the plunger hole are both circular parts, they can achieve high precision matching, so the volumetric efficiency is high.

[0004] At present, the axial piston pump has the following disadvantages:

[0005] (1) The bearing support structure is a dynamic pressure support, the bearing life is low, and it cannot bear the axial force. In the case of axial force, the pump will be damaged. The plunger cylinder operates by dynamic pressure support, and the speed cannot be too low. If it is too low, the dynamic pressure support of the plunger cylinder will fail and tilt, which will cause the piston to return to failure, causing irreversible damage to the pump. This bearing structure has many limitations on the operating conditions of the pump. If the installation and operation are not in place, it will cause serious irreversible damage to the pump. It often causes users to hesitate.

[0006] (2) The friction pair in the piston pump is a combination of stainless steel and PEEK (poly-ether-ether-ketone, polyether ether ketone) plastic. In many environments, the tolerance to particles is very poor, and the application environment of the pump is quite demanding. The medium water requirement requires a filter core with an absolute accuracy of 5um for filtration. However, the tolerance to many material liquid particles is poor. At present, it is only applied to seawater desalination and ultrapure water cleaning. The application environment of other material liquids is not ideal, and the service life is only about 30% of the rated life.

[0007] (3) The forced return structure of the plunger uses a center spring return. If the spring fails, the device cannot operate normally. If there is an axial force, the product will also fail.

[0008] Therefore, it is necessary to propose an axial piston pump structure to overcome the above-mentioned defects. SUMMARY

[0009] The purpose of the present application is to provide an axial piston pump structure, which prolongs the service life of the piston pump by optimizing the structure of each component and the optimization of material selection.

[0010] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is: an axial plunger pump, comprising a pump shell assembly, a bottom plate and an inlet and outlet flange, the bottom plate is located at the bottom of the pump shell assembly, the inlet and outlet flange is located at the top of the pump shell assembly, the pump shell assembly, the bottom plate and the inlet and outlet flange form an inner cavity for arranging other structures of the plunger pump, the inner cavity is arranged with a plunger cylinder assembly, a plunger and a plunger forced return assembly and a swash plate assembly, a transmission shaft passes through the inlet and outlet flange and is connected with the plunger cylinder assembly, the plunger and the plunger forced return assembly comprise a plunger assembly and a forced return mechanism, the plunger assembly comprises a ceramic plunger and a ceramic sliding shoe combined together, the forced return mechanism comprises a return disc, a ball hinge, a return guide column and a pre-tension spring; the ceramic sliding shoe is connected to the return disc and supported on the inclined surface of the swash plate assembly; the plane of the ball hinge forms a plane friction pair with the return disc, and the spherical surface of the ball hinge is hingedly connected with the ball socket of the return guide column; the return guide column is installed in the return guide sleeve of the plunger cylinder assembly, a plurality of spring holes for installing the pre-tension spring are arranged on one side of the return guide column relative to the ball socket, and the end of the pre-tension spring protrudes out of the spring hole and abuts against the plunger cylinder assembly.

[0011] The ball socket of the return guide column is provided with a central through hole, and an Archimedes spiral damping groove is arranged around the central through hole; the bottom surface of the ball hinge is provided with a convection damping hole penetrating the spherical surface, the convection damping hole is in communication with the central through hole, and a labyrinth static pressure support water pad is arranged around the convection damping hole.

[0012] The plunger assembly comprises a ceramic plunger and a ceramic sliding shoe, a central hole and a ball head damping groove around the central hole are arranged on the plunger ball head of the ceramic plunger, and the ball head damping groove is an Archimedes spiral groove; a sliding shoe damping hole capable of communicating with the central hole is arranged at the center of the end surface of the ceramic sliding shoe, and a static pressure water pad with a sealing band is arranged around the sliding shoe damping hole.

[0013] The swash plate assembly comprises a metal swash plate and a friction disc fixed on the inclined surface of the swash plate, and the friction disc comprises a ceramic inner ring and a metal outer ring connected by interference.

[0014] The plunger cylinder assembly comprises a plunger cylinder and a static pressure inner ring arranged outside the plunger cylinder, the ceramic plunger of the plunger assembly is movably arranged in the plunger sleeve of the plunger cylinder, one end of the plunger cylinder is in driving connection with the transmission shaft, and the other end is provided with a return guide sleeve, and the return guide sleeve and the return guide column of the forced return mechanism form a matched guide.

[0015] The pump housing assembly comprises an outer pump housing and an inner static pressure outer ring, both of which are made of ceramic material and constitute a static pressure main bearing; the static pressure outer ring is supported on a supporting surface at the end of the static pressure inner ring, a static pressure pad is arranged on the outer circular surface of the static pressure inner ring, and a high-pressure water annular groove is arranged on the outer circular surface of the static pressure outer ring, which is communicated with the static pressure pad through a pressure supply hole of the static pressure main bearing; one end of the static pressure outer ring is provided with a dynamic pressure supporting friction surface, which is in frictional contact with the supporting surface, and a plurality of Archimedes spiral convective grooves are arranged on the dynamic pressure supporting friction surface along the circumferential direction thereof.

[0016] The static pressure pad of the static pressure inner ring is in a wedge-shaped stepped structure, comprising a first static pressure water pad and a second static pressure water pad, one second static pressure water pad is arranged at each axial end of the first static pressure water pad, the first static pressure water pad is lower than the two second static pressure water pads, forming a stepped structure; the two second static pressure water pads are both in a wedge-shaped structure, and the small-diameter end is connected with the first static pressure water pad.

[0017] Both ends of the static pressure main bearing are respectively provided with a flow distribution and flow sealing axial thrust bearing and an end axial bearing, wherein the flow distribution and flow sealing axial thrust bearing is adjacent to the water inlet and outlet flange, and the end axial bearing is located at the pump bottom and surrounds the swash plate assembly;

[0018] The flow distribution and flow sealing axial thrust bearing comprises a thrust disc guiding assembly, a thrust disc assembly and a flow distribution disc assembly which are coaxially arranged in sequence, the thrust disc guiding assembly, the thrust disc assembly and the flow distribution disc assembly are all in a circular ring disc structure, a thrust mechanism is coaxially arranged outside the central hole of the thrust disc guiding assembly, the thrust mechanism is connected with the plunger cylinder end surface of the plunger cylinder assembly, the guide on the thrust disc guiding assembly is sealingly connected with the plunger sleeve of the plunger cylinder, and the flow distribution and flow sealing axial thrust bearing is provided with a medium channel which is communicated with the plunger sleeve.

[0019] The end axial bearing is in a cylindrical shape, comprising a PEEK sleeve ring and an alloy inner core embedded in the PEEK sleeve ring, an end surface of the PEEK sleeve ring facing the static pressure main bearing is provided with a combined surface, the combined surface is in contact with the inner ring friction surface of the static pressure inner ring, and the combined surface comprises a wedge surface, a bearing supporting surface and a second Archimedes spiral convective groove which are connected in sequence, the angle of the wedge surface is 1-2°, and a plurality of combined surfaces are sequentially arranged along the circumferential direction on the end surface of the axial thrust bearing.

[0020] The thrust mechanism comprises a thrust stop ring and a plurality of springs installed on the same side of the thrust stop ring, the plurality of springs are arranged at intervals along the circumferential direction of the thrust stop ring, the thrust stop ring is installed in the annular groove of the plunger cylinder assembly end surface, and the annular groove is provided with spring guide holes for accommodating the thrust springs;

[0021] The thrust disc assembly comprises a thrust disc support ring and a thrust disc wear-resistant ceramic ring coaxially connected, the outer circular surface of the thrust disc wear-resistant ceramic ring is assembled on the inner circular surface of the thrust disc support ring, and the thrust disc support ring is a metal ring; and a plurality of valve holes are arranged on the thrust disc wear-resistant ceramic ring in a circumferential direction at intervals;

[0022] The distribution disc assembly comprises a distribution disc support ring and a distribution disc ceramic wear-resistant ring coaxially connected, the distribution disc support ring is a metal ring, the outer circular surface of the distribution disc ceramic wear-resistant ring is assembled on the inner circular surface of the distribution disc support ring, and a plurality of distribution holes are arranged on the distribution disc ceramic wear-resistant ring in a circumferential direction at intervals;

[0023] The through hole on the thrust disc guide assembly, the distribution hole on the distribution disc assembly and the valve hole on the thrust disc assembly are communicated to form the medium channel.

[0024] The flange of the water inlet and outlet is made of ceramic material, and a static pressure bearing high-pressure water supply port, a convection groove, a water inlet and a water outlet are arranged on the flange; the static pressure bearing high-pressure water supply port is used for providing high-pressure water for a static pressure main bearing; the water inlet and the water outlet are arranged around the flange hole at the center of the flange, and are used for water inlet and outlet of the plunger pump.

[0025] The beneficial effects of the present application are: 1. The stress bearing assembly, the plunger forced return assembly, the plunger cylinder structure optimization and the swash plate structure optimization of the present application make the plunger pump can bear a larger axial force, under the action of the axial force, the pump will not fail, and can normally operate; at the same time, it is more resistant to vibration, swing and impact, and can normally operate in a large swing and large impact adverse environment.

[0026] 2. The friction pair in the present application adopts a ceramic friction pair, and an alloy is used to strengthen the ceramic structure, the lubrication design of the friction pair is optimized, more static pressure support lubrication is adopted, the resistance to medium particles is improved, therefore, the water inlet medium does not need a 5μm filter for treatment, but a conventional 20μm filter, so that the application range of the axial plunger pump can be expanded.

[0027] 3. Through the heat dissipation flow channel, the convection flow channel, the dynamic pressure lubrication design and the static pressure lubrication design, the cavitation structure is reduced, the noise is reduced, and the service life of the product is improved.

[0028] 4. More static pressure, dynamic pressure, damping and other design elements are adopted, so that the service life and reliability of the product are further improved. BRIEF DESCRIPTION OF DRAWINGS

[0029] Fig. 1 is an axial sectional view of the axial plunger pump of the present application;

[0030] Fig. 2 is an axial sectional view of the stress bearing assembly of the axial plunger pump of the present application;

[0031] Fig. 3 is a structural schematic diagram of the flow distribution and flow distribution sealing axial thrust bearing;

[0032] Fig. 4 is a structural schematic diagram of the thrust disc guide assembly in Fig. 3;

[0033] Fig. 5 is a structural schematic diagram of the pre-sealing thrust mechanism in Fig. 3;

[0034] Fig. 6 is an axial sectional view of the thrust disc assembly in Fig. 3;

[0035] Fig. 7 is an axial sectional view of the flow distribution disc in Fig. 3;

[0036] Fig. 8 is a structural schematic diagram of the static pressure inner ring of the static pressure main bearing in the load bearing assembly;

[0037] Fig. 9 is a sectional view of the static pressure inner ring of the static pressure main bearing in the load bearing assembly;

[0038] Fig. 10 is a structural schematic diagram of the static pressure outer ring of the static pressure main bearing in the load bearing assembly;

[0039] Fig. 11 is a structural schematic diagram of the end axial bearing in the load bearing assembly;

[0040] Fig. 12 is a structural schematic diagram of the transmission shaft and the plunger cylinder in the axial plunger pump of the present application;

[0041] Fig. 13 is a schematic diagram of the cooperation between the pump shell and the static pressure outer ring in the axial plunger pump of the present application;

[0042] Fig. 14 is a structural schematic diagram of the inlet and outlet port flange in the axial plunger pump of the present application;

[0043] Fig. 15 is a structural schematic diagram of the plunger and the plunger forced return mechanism in the axial plunger pump of the present application;

[0044] Fig. 16 is a structural schematic diagram of the return guide sleeve in Fig. 15;

[0045] Fig. 17 is a structural schematic diagram of the return guide column in Fig. 15;

[0046] Fig. 18 is a structural schematic diagram of the ball hinge in Fig. 15;

[0047] Fig. 19 is a structural schematic diagram of the plunger and the combined sliding shoe in the axial plunger pump of the present application;

[0048] Fig. 20 is a structural schematic diagram of the plunger and the clamping sliding shoe in the axial plunger pump of the present application;

[0049] Fig. 21 is a structural schematic diagram of the plunger in the axial plunger pump of the present application;

[0050] Fig. 22 is a structural schematic diagram of the swash plate assembly in the axial plunger pump of the present application;

[0051] Fig. 23 is a schematic diagram of the structure of the friction disc in Fig. 22;

[0052] Fig. 24 is a schematic diagram of the principle of the axial plunger pump of the present application requiring the outside of the pump to pass through the convection pipe;

[0053] Fig. 25 is a schematic diagram of the setting of the convection hole on the outside of the axial plunger pump of the present application;

[0054] Marked in the figure: 1, flow distribution and flow distribution sealing axial thrust bearing, 1.1, thrust disc guide assembly, 1.1.1, bolt, 1.1.2, through-hole sealing element, 1.1.3, guide element, 1.1.4, guide sealing element; 1.2, pre-sealing thrust mechanism, 1.2.1, thrust check ring, 1.2.2, thrust spring; 1.3, thrust disc assembly, 1.3.1, thrust disc support ring, 1.3.2, thrust disc ceramic wear-resistant ring, 1.3.3, valve hole, 1.3.4, threaded hole; 1.4, flow distribution disc assembly; 1.4.1, flow distribution disc support ring, 1.4.2, flow distribution disc ceramic wear-resistant ring, 1.4.3, flow distribution hole;

[0055] 2, plunger cylinder assembly, 2.1, static pressure inner ring, 2.1.1, inner ring friction surface, 2.1.2, static pressure pad, 2.1.2.1, first static pressure water pad, 2.1.2.2, second static pressure water pad, 2.1.3, static pressure inner ring support surface, 2.1.4, damping ring belt; 2.2, plunger cylinder, 2.3, return guide sleeve, 2.3.1, spiral lubrication flow channel, 2.4, plunger sleeve, 2.5, inlaid alloy sleeve, 2.5.1, thrust spring guide hole, 2.5.2, convection hole;

[0056] 3, pump shell assembly, 3.1, static pressure outer ring, 3.1.1, high-pressure water annular groove, 3.1.2, static pressure main bearing pressure supply hole, 3.1.3, dynamic pressure support friction surface; 3.2, pump shell, 3.2.1, static pressure support high-pressure water plug hole, 3.2.2, pump shell convection pipe interface, 3.3, pump bottom convection pipe interface;

[0057] 4, plunger and plunger forced return assembly, 4.1, ceramic plunger, 4.1.1, plunger ball head, 4.1.2, ball head damping groove, 4.2, return disc, 4.3, ball hinge, 4.3.1, labyrinth static pressure support water pad, 4.3.2, convection damping hole, 4.4, return guide column, 4.4.1, ball socket, 4.4.2, center through hole, 4.4.3, Archimedes spiral damping groove, 4.5, pre-degree spring, 4.6, ceramic sliding shoe, 4.6.1, sliding shoe damping hole, 4.6.2, static pressure water pad with sealing belt, 4.7, ceramic pressure sleeve, 4.8, ceramic ring, 4.9, metal retaining ring;

[0058] 5, swash plate assembly, 5.1, swash plate, 5.2, friction disc, 5.2.1, ceramic inner ring, 5.2.2, metal outer ring;

[0059] 6. damper;

[0060] 7. water inlet and outlet flange, 7.1. high pressure water supply for static pressure bearing, 7.2. convection groove, 7.3. reinforcing rib, 7.4. water inlet, 7.5. water outlet, 7.6. flange convection pipe interface;

[0061] 8. drive shaft;

[0062] 9. end axial bearing, 9.1. PEEK sleeve ring, 9.1.1. wedge surface, 9.1.2. bearing support surface, 9.1.3. second Archimedes spiral convection groove, 9.2. alloy core. DETAILED DESCRIPTION

[0063] The application will be further described in detail below in conjunction with the drawings and examples, but not as any limitation on the application.

[0064] Referring to FIG. 1, an axial plunger pump includes a pump shell assembly 3, a bottom plate at the bottom of the pump shell assembly 3, and a water inlet and outlet flange 7 at the top of the pump shell assembly 3, which form an inner cavity for other structures of the plunger pump. A damper 6 is arranged between the water inlet and outlet flange and the pump shell assembly. The damper 6 is a thin-walled orifice damper to improve damping effect and enhance stability. In the inner cavity, there are arranged a flow distribution and sealing axial thrust bearing 1, a plunger cylinder assembly 2, a plunger and plunger forced return assembly 4, a swash plate assembly 5, and an end axial bearing 9. A drive shaft 8 passes through the water inlet and outlet flange 7 and is connected with the plunger cylinder assembly 2 to drive the plunger cylinder to rotate.

[0065] As shown in FIG. 12, a static pressure inner ring 2.1 is mounted outside the plunger cylinder in the plunger cylinder assembly 2. As shown in FIG. 13, the pump shell assembly 3 includes a pump shell 3.2 and a static pressure outer ring 3.1 arranged inside the pump shell 3.2. The static pressure inner ring 2.1 and the static pressure outer ring 3.1 form a static pressure main bearing, which, together with the flow distribution and sealing axial thrust bearing 1 and the end axial bearing 9, forms a force bearing assembly in the plunger pump, as shown in FIG. 2. The flow distribution and sealing axial thrust bearing 1 and the end axial bearing 9 are respectively located at the two ends of the static pressure main bearing.

[0066] As shown in Fig. 3, the flow distribution and flow distribution sealing axial thrust bearing 1 comprises a thrust disc guide assembly 1.1, a pre-seal thrust mechanism 1.2, a thrust disc assembly 1.3 and a flow disc assembly 1.4. The flow distribution and flow distribution sealing axial thrust bearing 1 shown in Fig. 3 is an inverted structure diagram, the thrust disc guide assembly 1.1 is in the form of a whole circular disc structure, located at the bottom of the flow distribution and flow distribution sealing axial thrust bearing 1; the flow disc assembly 1.4 is in the form of a whole circular disc structure, located at the top of the flow distribution and flow distribution sealing axial thrust bearing 1; the thrust disc assembly is in the form of a whole circular disc structure, located between the flow disc assembly 1.4 and the thrust disc guide assembly 1.1; the pre-seal thrust mechanism 1.2 is in the form of a ring, arranged on the bottom surface of the thrust disc guide assembly 1.1. The thrust disc guide assembly 1.1, the pre-seal thrust mechanism 1.2, the thrust disc assembly 1.3 and the flow disc assembly 1.4 are coaxially arranged, and are connected by bolts.

[0067] As shown in Fig. 4, the thrust disc guide assembly 1.1 comprises a ring-shaped disc, through holes penetrating the upper and lower surfaces of the disc are arranged at intervals in the circumferential direction of the disc, and a guide piece 1.1.3 is installed at the through hole opening of the lower surface of the disc, the guide piece 1.1.3 is used to extend into the plunger sleeve 2.4 (see Fig. 12) of the plunger cylinder, and a guide sealing piece 1.1.4 such as a sealing ring is also installed on the outer cylindrical surface of the guide piece 1.1.3 to achieve sealing between the guide piece 1.1.3 and the plunger sleeve 2.4; the upper surface of the disc is also provided with a through hole sealing piece 1.1.2 around the through hole. Bolts 1.1.1 are installed on the disc to connect the thrust disc assembly 1.3 and the flow disc assembly 1.4. Alternatively, other fasteners can also be used instead of the bolts 1.1.1.

[0068] As shown in Fig. 5, the pre-seal thrust mechanism 1.2 comprises a thrust check ring 1.2.1 and thrust springs 1.2.2 installed on the lower surface of the thrust check ring 1.2.1, the thrust springs 1.2.2 are multiple and arranged at intervals in the circumferential direction of the thrust check ring 1.2.1. In the plunger pump, the thrust check ring 1.2.1 is installed in the annular groove on the end surface of the plunger cylinder, and a thrust spring guide hole 2.5.1 (see Fig. 12) is provided in the annular groove to accommodate the springs 1.2.2 and provide guidance for them.

[0069] As shown in Fig. 6, the thrust disc assembly 1.3 comprises coaxially connected inner and outer rings, the outer ring being a thrust disc support ring 1.3.1 made of stainless steel or other metal material, and the inner ring being a thrust disc wear-resistant ceramic ring 1.3.2, wherein a plurality of valve holes 1.3.3 are arranged on the thrust disc wear-resistant ceramic ring 1.3.2 in a circumferential direction, and the valve holes 1.3.3 are waist-shaped holes. The outer circumferential surface of the thrust disc wear-resistant ceramic ring 1.3.2 is in contact with the inner circumferential surface of the thrust disc support ring 1.3.1. The thrust disc support ring 1.3.1 can provide support for the thrust disc wear-resistant ceramic ring 1.3.2 to ensure the overall strength of the thrust disc.

[0070] As shown in Fig. 7, the flow distribution disc assembly 1.4 comprises coaxially connected inner and outer rings, the outer ring being a flow distribution disc support ring 1.4.1 made of stainless steel or other metal material, and the inner ring being a flow distribution disc ceramic wear-resistant ring 1.4.2, wherein a plurality of flow distribution holes 1.4.3 are arranged on the flow distribution disc ceramic wear-resistant ring 1.4.2 in a circumferential direction, and the flow distribution holes 1.4.3 are waist-shaped holes. The outer circumferential surface of the flow distribution disc ceramic wear-resistant ring 1.4.2 is in contact with the inner circumferential surface of the flow distribution disc support ring 1.4.1. The flow distribution disc support ring 1.4.1 can provide support for the flow distribution disc ceramic wear-resistant ring 1.4.2 to ensure the overall strength of the flow distribution disc.

[0071] After the thrust disc guide assembly 1.1, the thrust disc assembly 1.3 and the flow distribution disc assembly 1.4 are connected, the through hole on the thrust disc guide assembly 1.1, the flow distribution holes 1.4.3 on the flow distribution disc assembly 1.4 and the valve holes 1.3.3 on the thrust disc assembly 1.3 are communicated, as shown in Fig. 3.

[0072] As shown in Fig. 8 and Fig. 9, the static pressure inner ring 2.1 is a cylindrical ceramic structure, one end of which is provided with a radial flange, the end face of the radial flange is the inner ring friction surface 2.1.1, which is used to form a friction pair with the end face of the end axial bearing 9, the surface of the radial flange opposite to the inner ring friction surface 2.1.1 is the support surface 2.1.3, which is used to be in friction contact with the end face of the static pressure outer ring 3.1; the other end of the static pressure inner ring 2.1 is provided with a damping ring 2.1.4 relative to the radial flange, which is convenient for forming the damping required by the static pressure support; the outer circular surface of the static pressure inner ring 2.1 is provided with a static pressure pad 2.1.2, in order to meet the requirement of not wearing the static pressure main bearing when the static pressure is not established, the static pressure pad 2.1.2 includes a first static pressure water pad 2.1.2.1 and a second static pressure water pad 2.1.2.2 in a wedge-shaped stepped structure, so as to obtain good dynamic pressure characteristics. As shown in Fig. 9, the static pressure pad 2.1.2.1 is provided with a second static pressure water pad 2.1.2.2 at each of the two axial ends, the first static pressure water pad 2.1.2.1 is lower than the two second static pressure water pads 2.1.2.2, forming a stepped structure; at the same time, the two second static pressure water pads 2.1.2.2 are both wedge-shaped structures, the small-diameter end of which is connected with the first static pressure water pad 2.1.2.1, so as to form the wedge-shaped stepped structure.

[0073] The static pressure outer ring 3.1 is a cylindrical ceramic structure, which is sleeved on the outer circular surface of the static pressure inner ring 2.1. As shown in Fig. 10, one end of the static pressure outer ring 3.1 is provided with a dynamic pressure support friction surface 3.1.3, which is used to be in friction contact with the support surface 2.1.3 of the static pressure inner ring 2.1, the dynamic pressure support friction surface 3.1.3 is provided with a first Archimedes spiral line counterflow groove arranged in a circumferential direction, which can enhance the convection, enhance the heat dissipation, improve the dynamic pressure support, reduce the friction and wear, and improve the product life. The outer circular surface of the static pressure outer ring 3.1 is provided with a high-pressure water annular groove 3.1.1, which provides high-quality support force for the ceramic static pressure main bearing, reduces the damage to the ceramic under the condition of periodic load, and the groove is located at the position where the bearing bears the maximum shear force. The high-pressure water annular groove 3.1.1 is provided with a static pressure main bearing pressure supply hole 3.1.2, which corresponds to the first static pressure water pad 2.1.2.1 in the static pressure pad 2.1.2 after the static pressure outer ring 3.1 is assembled on the static pressure inner ring 2.1.

[0074] The structure of the end axial bearing 9 is shown in Fig. 11, the end axial bearing 9 is a cylindrical structure with small height, which is arranged around the swash plate assembly in the plunger pump. The end axial bearing 9 includes a PEEK sleeve ring 9.1 shown in Fig. 2 and an alloy inner core 9.2 embedded in the PEEK sleeve ring 9.1, since the present application needs to bear a large axial impact, the PEEK material with good toughness and wear resistance is selected as the outer sleeve ring structure, and the alloy inner core 9.2 made of metal material is embedded in the PEEK sleeve ring, which can enhance the shear resistance of the PEEK sleeve ring.

[0075] The end surface of the end axial bearing 9 towards the static pressure main bearing is provided with a plurality of combined surfaces distributed in the circumferential direction, the combined surface is in contact with the inner ring friction surface 2.1.1 of the static pressure inner ring 2.1, and the combined surface includes a wedge surface 9.1.1, a bearing support surface 9.1.2 and a second Archimedes spiral line convection groove 9.1.3 connected in sequence, the angle of the wedge surface 9.1.1 is 1-2°, which is used to induce the formation of dynamic pressure support, improve dynamic pressure support, reduce friction and wear with the static pressure inner ring 2.1, and improve product life; the bearing support surface 9.1.2 is a plane, mainly serving as auxiliary support; the second Archimedes spiral line convection groove 9.1.3 can enhance convection, enhance heat dissipation, improve dynamic pressure support, reduce friction and wear, and improve product life.

[0076] The structure of the plunger cylinder assembly 2 is shown in Figure 12, which includes the static pressure inner ring 2.1 and the plunger cylinder 2.2, the plunger cylinder 2.2 is sleeved on the inner circular surface of the static pressure inner ring 2.1, the center of the plunger cylinder 2.2 is in transmission connection with the transmission shaft 8, the plunger cylinder 2.2 is driven to rotate by the transmission shaft 8, a plurality of plunger sleeve 2.4 embedded plunger holes are uniformly and intermittently distributed around the transmission shaft 8 on the plunger cylinder 2.2, the plunger sleeve 2.4 is made of ceramic material, the setting of the plunger sleeve 2.4 can avoid the wear of the plunger to the plunger hole, after using for a period of time and the plunger sleeve 2.4 is worn, only the plunger sleeve 2.4 needs to be replaced, avoiding the overall replacement of the plunger cylinder 2.2. The center of the plunger cylinder 2.2 is also embedded with a return guide sleeve 2.3, which is used to cooperate with the plunger forced return mechanism to guide the forced return of the plunger. The plunger cylinder 2.2 is also embedded with an inlaid alloy sleeve 2.5 around the transmission shaft 8, the end surface of the inlaid alloy sleeve 2.5 is provided with a sink groove for mounting the thrust check ring 1.2.1, the groove bottom is arranged with a plurality of annularly distributed thrust spring guide holes 2.5.1, which accommodate the thrust spring 1.2.2 and guide the compression of the thrust spring 1.2.2. The inlaid alloy sleeve 2.5 is also provided with a convection hole 2.5.2, which can be used for heat dissipation of the transmission shaft.

[0077] The structure of the pump shell assembly 3 is shown in Figure 13, which includes the outer pump shell 3.2 and the inner static pressure outer ring 3.1, the pump shell 3.2 is made of corrosion-resistant metal material, provided with a static pressure support high-pressure water plug hole 3.2.1 and a pump shell convection pipe interface 3.2.2, the static pressure support high-pressure water plug hole 3.2.1 is aligned with and can communicate with the static pressure main bearing pressure supply hole 3.1.2, the pump shell convection pipe interface 3.2.2 is a threaded interface, which is used to connect with the external convection pipe, and is used for exhaust, emptying or pollution discharge of the plunger pump.

[0078] The structure of the water inlet and outlet flange 7 is shown in Figure 14. The water inlet and outlet flange 7 is made of ceramic material, and is provided with a static pressure bearing high pressure water supply port 7.1, a convection groove 7.2, a water inlet 7.4 and a water outlet 7.5. The static pressure bearing high pressure water supply port 7.1 provides high pressure water for the static pressure support of the static pressure main bearing composed of the static pressure inner ring 2.1 and the static pressure outer ring 3.1 through flow matching and flow matching sealing between the gap between the axial thrust bearing 1 and the pump shell. The convection groove 7.2 is used for heat dissipation and cooling. The water inlet 7.4 and the water outlet 7.5 are arranged around the flange hole in the center of the flange, and are used for water inlet and water outlet of the plunger pump. The water outlet and the water inlet are opened on the side of the water inlet and outlet flange, and part of the high pressure water flowing out of the water outlet 7.5 can enter the high pressure water supply port 7.1. The flange hole is used for the transmission shaft 8 to pass through. The water outlet 7.5 needs to discharge high pressure water, in order to make up for the problem of ceramic brittleness, the edge of the water outlet 7.5 is also provided with a reinforcing rib 7.3.

[0079] The structure of the plunger and plunger forced return assembly 4 is shown in Figure 15, which includes a plurality of ceramic plungers 4.1, a return disc 4.2, a spherical hinge 4.3, a return guide column 4.4, a pre-degree spring 4.5 and a ceramic sliding shoe 4.6 (see Figures 19 and 20). The ceramic plunger 4.1 is connected with the ceramic sliding shoe 4.6 to form a plunger assembly, and is connected to the return disc 4.2 through the ceramic sliding shoe 4.6. One side of the spherical hinge 4.3 is a plane, and the other side is a spherical surface. The spherical hinge 4.3 is arranged in the center of the return disc 4.2, and the plane of the spherical hinge 4.3 forms a plane friction pair with the return disc 4.2, and the friction pair track is an ellipse. The return guide column 4.4 is made of ceramic material, and is installed in the return guide sleeve 2.3. The return guide sleeve 2.3 is embedded in the plunger cylinder 2.2, one end of the return guide column 4.4 forms a spherical pair with the spherical surface of the spherical hinge 4.3, and the other end is provided with a spring hole for installing the pre-degree spring 4.5. The pre-degree spring 4.5 is exposed from the spring hole and can be pressed against the cylinder body of the plunger cylinder 2.2. The pre-degree spring 4.5 refers to a spring with moderate pre-pressing, which has a movement space of 0.1-0.2mm, and provides reliable support for safe forced return. The pre-degree spring 4.5 does not act under normal operating conditions of the plunger pump, and the return work of the plunger assembly is performed by the return disc 4.2, the spherical hinge 4.3 and the return guide column 4.4. Only in the case of receiving a relatively large external force, the pre-degree spring 4.5 can be used for unloading return, so as to avoid irreversible damage to the product caused by return failure.

[0080] As shown in Figure 16, the return guide sleeve 2.3 is made of ceramic material, and a spiral lubrication flow channel 2.3.1 is formed on the inner circular surface of the return guide sleeve 2.3, which is used for heat dissipation and lubrication under high temperature and high pressure, prevents the material from being stuck due to thermal expansion, and reduces the friction area between the return guide column 4.4 and the return guide sleeve 2.3, thereby reducing wear.

[0081] As shown in Figure 17, the side of the return guide column 4.4 for forming a spherical pair with the spherical hinge 4.3 is provided with a spherical socket 4.4.1, the center of the spherical socket 4.4.1 is provided with a center through hole 4.4.2 for heat dissipation and lubrication of the spherical surface of the spherical hinge 4.3; and the spherical socket 4.4.1 is further provided with an Archimedes spiral damping groove 4.4.3 around the center through hole 4.4.2, the opening direction of the Archimedes spiral damping groove 4.4.3 is consistent with the rotation direction, and the groove depth and width gradually change with the rotation of the groove. The setting of the Archimedes spiral damping groove 4.4.3 can improve the supporting force, enhance the lubricity, reduce the friction, reduce the wear and tear, and improve the service life of the parts.

[0082] As shown in Figure 18, the center of the bottom of the spherical hinge 4.3 is provided with a convection damping hole 4.3.2 penetrating through the spherical surface, the convection damping hole 4.3.2 communicates with the center through hole 4.4.2 of the return guide column 4.4, facilitating the flow of water; and a labyrinth static pressure support water pad 4.3.1 is arranged around the convection damping hole 4.3.2, which functions to enhance the spherical hinge end face supporting force under relatively low static pressure pad water pressure, improve the lubricity of friction, reduce friction and wear, and improve the service life of the parts.

[0083] Figures 19-21 show the specific structure of the plunger assembly, especially the different combination structure forms of the ceramic plunger 4.1 and the ceramic sliding shoe 4.6.

[0084] As shown in Figure 19, in the specific structure of the ceramic plunger 4.1 and the combined sliding shoe, the combined sliding shoe includes the ceramic sliding shoe 4.6 and the ceramic pressure sleeve 4.7, the plunger ball head 4.1.1 of the ceramic plunger 4.1 cooperates with the spherical surface of the ceramic sliding shoe 4.6, and the ceramic pressure sleeve 4.7 is installed outside the ceramic sliding shoe 4.6 as the spherical surface closing of the ceramic sliding shoe 4.6, wrapping the ceramic sliding shoe 4.6 and the plunger ball head 4.1.1 to avoid the ceramic plunger 4.1 from falling off the ceramic sliding shoe 4.6.

[0085] As shown in Figure 20, in the specific structure of the ceramic plunger 4.1 and the buckling sliding shoe, the buckling sliding shoe includes the ceramic sliding shoe 4.6, the ceramic ring 4.8 and the metal buckle ring 4.9. The plunger ball head 4.1.1 of the ceramic plunger 4.1 cooperates with the spherical surface of the ceramic sliding shoe 4.6, the spherical surface edge of the ceramic sliding shoe 4.6 is provided with a radial flange, the ceramic ring 4.8 is sleeved on the plunger ball head 4.1.1 and tightly attached to the radial flange; and the inner circular surface of the metal buckle ring 4.9 is provided with a buckling groove, the radial flange and the ceramic ring 4.8 are buckled in the buckling groove by the metal buckle ring 4.9, as the spherical surface closing of the ceramic sliding shoe 4.6, wrapping the ceramic sliding shoe 4.6 and the plunger ball head 4.1.1 to avoid the ceramic plunger 4.1 from falling off the ceramic sliding shoe 4.6.

[0086] No matter the combination shoe or the buckle shoe, the ceramic shoe 4.6 is provided with a shoe damping hole 4.6.1 with a thin-walled small hole in the center of the end face to enhance the temperature resistance. A static pressure water pad 4.6.2 with a sealing band is arranged around the shoe damping hole 4.6.1.

[0087] As shown in FIG. 21, the plunger ball head 4.1.1 of the ceramic plunger 4.1 is provided with a center hole in the center, which can communicate with the shoe damping hole 4.6.1 and the inner cavity of the ceramic plunger 4.1. A ball head damping groove 4.1.2 is also arranged on the spherical surface of the plunger ball head 4.1.1, which is an Archimedes spiral groove, which can improve the supporting force, enhance the lubricity, reduce the friction, reduce the wear and tear, and prolong the service life of the parts.

[0088] The structure of the swash plate assembly 5 is shown in FIG. 22, which includes a swash plate 5.1 and a friction plate 5.2. The swash plate 5.1 is made of corrosion-resistant alloy material to reduce the use of ceramics and reduce costs. The swash plate 5.1 has an annular inclined surface. The friction plate 5.2 is bonded to the inclined surface of the swash plate 5.1 by an adhesive. The structure of the friction plate 5.2 can be referred to FIG. 23, which includes a ceramic inner ring 5.2.1 and a metal outer ring 5.2.2. The ceramic inner ring 5.2.1 and the metal outer ring 5.2.2 are connected by interference, and the metal outer ring 5.2.2 compensates for the brittleness of the ceramic structure 5.2.1.

[0089] As shown in FIG. 24, in the plunger pump of the present application, with the CC line passing through the plunger active area as the boundary, due to the arrangement of the static pressure main bearing and the forced return mechanism, the low pressure chamber A1 on one side of the CC line between the transmission shaft and the water inlet and outlet flange and the low pressure chamber A2 on the other side of the CC line between the return disc and the plunger cylinder assembly cannot flow. Therefore, corresponding convection interfaces need to be arranged on the side or bottom of the pump, and the convection is carried out through the pipeline outside the pump. The arrangement of the convection interface is shown in FIG. 25, which includes a pump shell convection pipeline interface 3.2.2 arranged on the pump shell, a pump bottom convection pipeline interface 3.3 arranged on the pump bottom, and a flange convection pipeline interface 7.6 arranged on the side of the water inlet and outlet flange 7, which is screwed with the external convection pipeline through the arranged convection interface, to realize the pump exhaust, emptying and sewage operation.

[0090] The working principle of the plunger pump is as follows: the transmission shaft 8 rotates under the driving of an external motor or an internal combustion engine, and drives the plunger cylinder 2.2 to rotate, the plunger cylinder 2.2 drives the ceramic plunger 4.1 and the ceramic sliding shoe 4.6 to rotate along the inclined friction disc 5.2 of the swash plate assembly 5, and in the rotating movement, the ceramic plunger 4.1 reciprocates in the plunger sleeve 2.4, so that the volume of the plunger sleeve 2.4 changes, the low-pressure water is sucked in and the high-pressure water is pumped out. The low-pressure water enters through the water inlet 7.4 on the inlet and outlet flange 7, enters the plunger sleeve 2.4 of the plunger cylinder 2.2 through the flow distribution hole 1.4.3 of the flow distribution disc assembly 1.4 and the valve hole 1.3.3 of the thrust disc assembly 1.3, and is pressurized into high-pressure water by the ceramic plunger 4.1, and then the high-pressure water is discharged from the water outlet 7.5 of the inlet and outlet flange 7 through the valve hole 1.3.3 of the thrust disc assembly 1.3 and the flow distribution hole 1.4.3 of the flow distribution disc assembly 1.4.

[0091] The flow distribution disc assembly 1.4 is used to distribute the flow to the plunger sleeve 2.4 with changing volume during the rotation of the plunger cylinder 2.2. The thrust disc assembly 1.3 is mainly used to seal the thrust disc and the flow distribution disc assembly 1.4, because the thrust disc is floating, and can compensate the wear of the flow distribution disc assembly 1.4 caused by the external unbalanced force.

[0092] The above examples are only used to illustrate the technical solutions of the present application, but not to limit it, and those skilled in the art should understand that the specific embodiments of the present application can be modified or replaced by the same, and any modification or replacement which does not deviate from the spirit and scope of the present application is within the protection scope of the claims.

Claims

1. An axial piston pump, comprising a pump housing assembly, a base plate, and inlet / outlet flanges, wherein the base plate is located at the bottom of the pump housing assembly, and the inlet / outlet flanges are located at the top of the pump housing assembly; the pump housing assembly, the base plate, and the inlet / outlet flanges form an inner cavity for other structures of the piston pump; a piston cylinder assembly, a piston, a piston forced return assembly, and a swashplate assembly are disposed within the inner cavity; a drive shaft passes through the inlet / outlet flanges and is connected to the piston cylinder assembly; characterized in that: The plunger and plunger forced return assembly comprises a plunger assembly and a forced return mechanism, the plunger assembly comprises a ceramic plunger and a ceramic shoe combined together, and the forced return mechanism comprises a return disc, a ball hinge, a return guide column and a pre-tension spring; the ceramic shoe is connected to the return disc and supported on the inclined surface of the swash plate assembly; the plane of the ball hinge forms a plane friction pair with the return disc, and the spherical surface of the ball hinge is hingedly connected to the ball socket of the return guide column; the return guide column is installed in the return guide sleeve of the plunger cylinder assembly, a plurality of spring holes for installing the pre-tension spring are arranged on one side of the return guide column relative to the ball socket, and the end of the pre-tension spring is exposed from the spring hole and abuts against the plunger cylinder assembly.

2. The axial piston pump of claim 1, characterized in that: The ball socket of the return guide column is provided with a central through hole, and an Archimedes spiral damping groove is arranged around the central through hole; the bottom surface of the ball hinge is provided with a convection damping hole penetrating through the spherical surface, the convection damping hole is in communication with the central through hole, and a labyrinth static pressure support water pad is arranged around the convection damping hole.

3. The axial piston pump of claim 1, wherein: The plunger assembly comprises a ceramic plunger and a ceramic shoe, a central hole and a spherical head damping groove around the central hole are arranged on the plunger spherical head of the ceramic plunger, and the spherical head damping groove is an Archimedes spiral groove; a shoe damping hole capable of being in communication with the central hole is arranged at the center of the end surface of the ceramic shoe, and a static pressure water pad with a sealing band is arranged around the shoe damping hole.

4. The axial piston pump of claim 1, wherein: The swash plate assembly comprises a swash plate made of metal and a friction disc fixed on the inclined surface of the swash plate, and the friction disc comprises a ceramic inner ring and a metal outer ring connected by interference.

5. The axial piston pump of claim 1, wherein: The plunger cylinder assembly comprises a plunger cylinder and a static pressure inner ring arranged outside the plunger cylinder, the ceramic plunger of the plunger assembly is movably arranged in the plunger sleeve of the plunger cylinder, one end of the plunger cylinder is in driving connection with the transmission shaft, and the other end is provided with a return guide sleeve, and the return guide sleeve is in cooperation with the return guide column of the forced return mechanism.

6. The axial piston pump of claim 5, characterized in that: The pump housing assembly comprises an outer pump housing and an inner static pressure outer ring, the static pressure outer ring and the static pressure inner ring are both made of ceramic and constitute a static pressure main bearing; the static pressure outer ring is supported on the supporting surface at the end of the static pressure inner ring, a static pressure pad is arranged on the outer circular surface of the static pressure inner ring, a high-pressure water annular groove is arranged on the outer circular surface of the static pressure outer ring, the high-pressure water annular groove is in communication with the static pressure pad through a pressure supply hole of the static pressure main bearing; one end of the static pressure outer ring is provided with a dynamic pressure support friction surface, which is in frictional contact with the supporting surface, and a plurality of Archimedes spiral convection grooves are arranged on the dynamic pressure support friction surface along the circumferential direction thereof.

7. The axial piston pump of claim 6, characterized in that: The static pressure pad of the static pressure inner ring is a wedge-shaped stepped structure, comprising a first static pressure water pad and a second static pressure water pad, one second static pressure water pad is arranged at each of the two axial ends of the first static pressure water pad, the first static pressure water pad is lower than the two second static pressure water pads, and a stepped structure is formed; the two second static pressure water pads are both wedge-shaped structures, and the small-diameter end is connected to the first static pressure water pad.

8. The axial piston pump of claim 6, wherein: The static pressure main bearing is respectively provided with a flow distribution and flow sealing axial thrust bearing and an end axial bearing at both ends, the flow distribution and flow sealing axial thrust bearing is adjacent to the water inlet and outlet flange, and the end axial bearing is located at the pump bottom and arranged around the swash plate assembly. The flow distribution and sealing axial thrust bearing comprises a thrust disc guiding assembly, a thrust disc assembly and a flow distribution disc assembly arranged coaxially in sequence, the thrust disc guiding assembly, the thrust disc assembly and the flow distribution disc assembly are all annular disc structures, a thrust mechanism is arranged coaxially outside a central hole of the thrust disc guiding assembly, the thrust mechanism is connected with a plunger cylinder end surface of a plunger cylinder assembly, a guiding element on the thrust disc guiding assembly is sealingly connected with a plunger sleeve of the plunger cylinder, and the flow distribution and sealing axial thrust bearing is provided with a medium channel communicated with the plunger sleeve. The end axial bearing is in a cylindrical shape and comprises a PEEK sleeve ring and an alloy inner core embedded in the PEEK sleeve ring, a combined surface is arranged on an end surface of the PEEK sleeve ring facing the static pressure main bearing, the combined surface is in contact with an inner ring friction surface of the static pressure inner ring, and the combined surface comprises a wedge surface, a bearing support surface and a second Archimedes spiral counterflow groove connected in sequence, the angle of the wedge surface is 1-2°, and a plurality of combined surfaces are sequentially arranged on the end surface of the axial thrust bearing in a circumferential direction.

9. The axial piston pump of claim 8, characterized in that: The thrust mechanism comprises a thrust blocking ring and a plurality of springs mounted on the same side of the thrust blocking ring, the plurality of springs are arranged in a circumferential direction of the thrust blocking ring, the thrust blocking ring is mounted in an annular groove of the end surface of the plunger cylinder assembly, and the annular groove is provided with spring guide holes for accommodating the thrust springs. The thrust disc assembly comprises a thrust disc support ring and a thrust disc wear-resistant ceramic ring connected coaxially, an outer circular surface of the thrust disc wear-resistant ceramic ring is assembled on an inner circular surface of the thrust disc support ring, and the thrust disc support ring is a metal ring; a plurality of valve holes are arranged on the thrust disc wear-resistant ceramic ring in a circumferential direction. The flow distribution disc assembly comprises a flow distribution disc support ring and a flow distribution disc ceramic wear-resistant ring connected coaxially, the flow distribution disc support ring is a metal ring, an outer circular surface of the flow distribution disc ceramic wear-resistant ring is assembled on an inner circular surface of the flow distribution disc support ring, and a plurality of flow distribution holes are arranged on the flow distribution disc ceramic wear-resistant ring in a circumferential direction. The through hole on the thrust disc guiding assembly, the flow distribution hole on the flow distribution disc assembly and the valve hole on the thrust disc assembly are communicated to form the medium channel.

10. The axial piston pump of claim 7, wherein: The water inlet and outlet flange is made of ceramic material, and is provided with a static pressure bearing high-pressure water supply port, a counterflow groove, a water inlet and a water outlet; the static pressure bearing high-pressure water supply port is used for providing high-pressure water for the static pressure main bearing; the water inlet and the water outlet are arranged around a flange hole at the center of the flange and are used for water inlet and outlet of the plunger pump.

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