CN216714619U

CN216714619U - Fixed clearance return type high-pressure plunger water pump

Info

Publication number: CN216714619U
Application number: CN202123079622.2U
Authority: CN
Inventors: 贺小峰; 余威; 李银
Original assignee: Huazhong University of Science and Technology
Current assignee: Huazhong University of Science and Technology
Priority date: 2021-12-09
Filing date: 2021-12-09
Publication date: 2022-06-10
Anticipated expiration: 2031-12-09

Abstract

The utility model belongs to the field of displacement pumps, and particularly discloses a fixed-gap return type high-pressure plunger water pump which comprises a pump main body, a main shaft, a pre-tightening component, a swash plate, a return component and a plunger piston shoe component, wherein the pump main body comprises a rear end cover, a cylinder body, a shell base, a shell and a bearing seat which are sequentially connected; two ends of the main shaft are respectively movably connected with the shell base and the bearing seat, an inclined bending section and an inclined shaft disc are processed in the middle section of the main shaft, and a thrust self-aligning roller bearing is arranged between the back surface of the inclined shaft disc and the bearing seat; the pre-tightening component is arranged at the non-input end of the main shaft; the swash plate is arranged on the inclined bending section through an angular contact ball bearing and is arranged on the inclined surface of the swash plate through a thrust self-aligning roller bearing; the plunger piston shoe component comprises a plunger piston part and a piston shoe part, the plunger piston part is arranged in a plunger piston cavity formed in the cylinder body, and the piston shoe part is contacted with the swash plate through the return assembly. The utility model can improve the friction wear and the thermal wear in the existing oil-water separation type valve flow distribution plunger pump, and improve the working performance and the reliability of the existing oil-water separation type valve flow distribution plunger pump.

Description

Fixed clearance return type high-pressure plunger water pump

Technical Field

The utility model belongs to the field of displacement pumps, and particularly relates to a fixed-gap return type high-pressure plunger water pump.

Background

The axial plunger pump is one of the common volumetric pump structures, and forces the plunger to reciprocate in the plunger cavity of the cylinder body through the relative rotation between the swash plate and the cylinder body, so that the volume of the working cavity changes periodically, and the suction and the discharge of a working medium are completed under the coordination of the flow distribution device.

In the application field of water hydraulic pumps, the difficulty of sealing and lubricating is improved due to the physical and chemical properties of water, so that the existing water hydraulic pump mainly adopts a plunger pump form with relatively good friction conditions of a friction pair. Even so, the friction pairs in plunger hydraulic pumps still face serious wear problems. In the oil-water separation structure, although the slipper/swash plate friction pair can be lubricated by mineral oil, high-pressure water cannot be introduced into the bottom end of the slipper to realize static pressure support, which makes the PV value applied to the friction pair in the drainage stage large.

In order to overcome this problem, patent CN 200610019925.6 discloses an axial piston pump in which a cylinder body is fixed relative to a pump body and a main shaft is provided with a main shaft disc structure, wherein a swash plate is rotatably mounted on the main shaft disc through a bearing. The plunger pump indirectly drives the plunger to move by utilizing the swash plate, and the swash plate does not rotate relative to the cylinder body, so that the abrasion problem of a slipper/swash plate friction pair is effectively improved.

However, when the plunger pump runs at a high speed, the central spring return device adopted by the plunger pump may not enable the bottom surface of the sliding shoe to be always attached to the swash plate under the influence of inertia force, so that the sliding shoe inclines, the outer edge of the sliding shoe is eccentric and even is separated from the swash plate; meanwhile, the spring force of the return device acts on each slipper, so that the pressure of the slipper on the swash plate is increased, and the abrasion is not reduced. In addition, the ball wrapping structure adopted between the plunger ball head and the sliding shoe in the plunger pump can cause shoe removal or shoe loosening due to large friction force between the plunger and the sealing element and between the plunger and the cylinder sleeve; the integral structure of the plunger and the ball head thereof also restricts the matching of friction pair materials such as the plunger and a cylinder sleeve, the ball head and a sliding shoe and the like; because the volume of an oil cavity in the oil-water separation type water pump is limited, the temperature rise of lubricating oil is large under the action of viscous friction and mechanical friction, and a friction pair and a dynamic seal can generate thermal abrasion. These factors will affect the performance and operational reliability of the water pump to some extent.

SUMMERY OF THE UTILITY MODEL

Aiming at the defects or improvement requirements of the prior art, the utility model provides a fixed-gap return type high-pressure plunger pump, aiming at improving the friction wear and the thermal wear in the existing oil-water separation type valve flow distribution plunger pump and improving the working performance, the working stability and the reliability of the water pump.

In order to achieve the purpose, the utility model provides a fixed clearance return type high-pressure plunger water pump, which comprises a pump main body, a main shaft, a pre-tightening component, a swash plate, a return component and a plunger piston shoe component, wherein:

the pump main body comprises a rear end cover, a cylinder body, a shell base, a shell and a bearing seat which are connected in sequence;

two ends of the main shaft are respectively movably connected with the shell base and the bearing seat; an oblique bending section and an oblique shaft disc are machined in the middle section of the main shaft, and a self-aligning thrust roller bearing is installed between the back surface of the oblique shaft disc and the bearing seat;

the pre-tightening assembly is arranged at the non-input end of the main shaft and used for providing pre-tightening force for the self-aligning thrust roller bearing on the back of the inclined shaft disc;

the swash plate is mounted on the inclined bending section through an angular contact ball bearing and mounted on the inclined surface of the swash plate through a thrust self-aligning roller bearing, and the working surface of the swash plate is parallel to the inclined surface of the swash plate;

the return assembly comprises a return disc and a clearance adjusting ring, the return disc is fixedly connected to the swash plate, and the clearance adjusting ring is installed between the return disc and the swash plate;

the plunger piston shoe assembly comprises a plunger part and a piston shoe part, the plunger part is movably arranged in a plunger cavity formed in the cylinder body, and the piston shoe part is nested and arranged between the return stroke disc and the swash plate.

Preferably, the slipper component comprises an outer slipper, an inner slipper and a plunger ball head, wherein the inner side wall surface of the outer slipper close to the direction of the plunger component and the top of the inner slipper are both spherical surfaces, the plunger ball head and the inner slipper are both arranged in the outer slipper, and the inner slipper is matched with the plunger ball head to form the slipper with a ball hinge; the sliding shoes are arranged in round holes which are uniformly distributed on the circumference of the return disc and are kept in contact with the swash plate; the center of the inner sliding shoe is provided with a through hole so as to facilitate the entry of oil.

More preferably, the outer shoe has a flange provided on the outer side thereof, the flange being fitted in a gap between the swash plate and the return plate formed by the gap adjustment ring, and the height of the gap being 0.02mm to 0.05mm greater than the thickness of the flange of the outer shoe.

Preferably, the plunger component comprises a plunger body and a ceramic plunger, one end of the plunger body is connected with the plunger ball head through an internal thread, and the ceramic plunger is sleeved on the outer side of the plunger body and is axially fixed.

Preferably, the cylinder body is circumferentially and uniformly distributed with a plurality of plunger cavities, and the wall surface of each plunger cavity is sequentially provided with a front guide bearing, a plunger sealing assembly and a rear guide bearing; the plunger component is arranged in the plunger cavity through the front guide bearing and the rear guide bearing and can slide along the axial direction; the outer surface of the ceramic plunger contacts with a sealing ring in the plunger sealing assembly to divide the inner space of the pump main body into a working medium cavity and a lubricating oil cavity.

As further preferred, the pump further comprises a suction valve assembly and a pressing valve assembly, and the rear end cover is provided with a pump inlet and a pump outlet; the suction valve assembly is arranged in a flow passage between the pump inlet and the plunger cavity, and the extrusion valve assembly is arranged in a flow passage between the plunger cavity and the pump outlet, so that the working medium cavity is sequentially divided into a low-pressure cavity, a working accommodating cavity and a high-pressure cavity.

Preferably, the suction valve assembly comprises a suction valve seat, a suction valve sleeve and a suction valve core, wherein a stepped hole is formed in the inner wall of the suction valve sleeve, the suction valve core is installed in a large-diameter hole cavity in the stepped hole, and one end of the suction valve core is pressed on the suction valve seat by a suction valve spring; and a window is formed in the middle of the suction valve sleeve and is communicated with the plunger cavity, and meanwhile, a stepped hole of the suction valve sleeve is communicated with the pump inlet.

Preferably, the diameter of the large-diameter bore in the stepped hole is larger than the outer diameter of the suction valve core, and the distance between the end face of the suction valve core on the side where the suction valve spring is installed and the stepped hole is larger than the maximum opening of the suction valve core under the rated working condition.

Preferably, the pre-tightening assembly comprises a central pre-tightening spring, a central spring seat and a steel ball, wherein the central pre-tightening spring and the central spring seat are arranged in a central blind hole of the cylinder body from inside to outside; the steel ball is arranged at the non-input end of the main shaft and is in contact with the central spring seat.

As a further preferred option, the cooling device further comprises a cooling assembly, wherein the cooling assembly comprises a damping screw plug, a water conveying pipeline, a heat dissipation copper coil pipe and a drainage pipeline which are connected in sequence, wherein the damping screw plug is installed at the outlet of the pump and is provided with a damping hole, so that the outlet flow channel of the pump is communicated with the water conveying pipeline; and the heat dissipation copper coil is immersed in oil in the lubricating oil cavity.

Generally, compared with the prior art, the above technical solution conceived by the present invention mainly has the following technical advantages:

1. the utility model adopts the fixed clearance return mechanism, solves the problem that the sliding shoe excessively inclines and even separates from the swash plate in the plunger return process, also avoids the additional pressure generated by the spring return structure on the sliding shoe/swash plate friction pair, lightens the abrasion of the sliding shoe/swash plate friction pair, prolongs the service life of the water pump, and reduces the vibration and noise during operation.

2. The main shaft pre-tightening assembly and the angular contact ball bearing for connecting the swash plate and the main shaft respectively provide pre-tightening force for the self-aligning thrust roller bearing on the back surface and the inclined surface of the swash plate, replace the corresponding function of a central spring return mechanism and enable the structure to be simpler and more compact. In addition, the production and processing cost, friction heating and abrasion caused by the spherical hinge friction pair of the central spring return device are avoided, the working condition of the water pump is improved, and the efficiency of the water pump is improved.

3. When the working pressure of the water pump is high, so that the main shaft is slightly bent, the thrust self-aligning roller bearing and the angular contact ball bearing have the aligning effect of keeping the working surface of the swash plate parallel to the inclined surface of the swash plate, and the reliability and the stability of the water pump are improved.

4. The combined type piston shoe structure enables the piston shoe to be made of materials with high strength and good wear resistance without adopting a ball wrapping process, avoids the problem that the plunger ball head and the piston shoe fall off due to overlarge return acting force, and improves the working reliability of the water pump.

5. The combined plunger structure not only gives consideration to the overall strength and rigidity of the plunger, improves the manufacturability of processing and assembling, but also increases the flexibility of selecting and matching the plunger/cylinder body (sleeve), the plunger ball head and the sliding shoe friction pair material, improves the working performance of the water pump and is beneficial to production and maintenance. Meanwhile, the service life of the friction pair is prolonged by adopting the wear-resistant and corrosion-resistant ceramic plunger, the influence of small-particle pollutants on the friction pair is favorably resisted due to the high hardness characteristic of the ceramic plunger, and the working stability and the pollution resistance of the water pump are improved.

6. By limiting the lifting height of the valve cores of the suction valve assembly and the extrusion valve assembly, the problem that the valve cores are excessively opened due to the action of inertia force when the water pump works at a high speed, so that the closing delay of the flow distribution valve is aggravated is solved, and the volume efficiency of the water pump at a high rotating speed is improved; meanwhile, the diameter of the large-diameter hole cavity of the valve sleeve stepped hole is slightly larger than the outer diameter of the valve core, so that a guiding effect is provided for the valve core and the valve core is prevented from inclining.

7. The cooling assembly is arranged in the lubricating oil cavity, so that the problems of thermal abrasion of a friction pair and a sealing piece, failure of lubricating oil and the like caused by overhigh oil temperature are solved, and the stability and reliability of long-time continuous operation of the water pump are improved.

Drawings

FIG. 1 is a schematic diagram of a fixed-gap return high-pressure plunger pump according to an embodiment of the present invention;

FIG. 2 is a schematic view of a plunger shoe assembly according to an embodiment of the present invention;

FIG. 3 is a schematic view of a configuration of a pressure valve assembly according to an embodiment of the present invention;

fig. 4 is a schematic view of the structure of a suction valve assembly according to an embodiment of the present invention.

The same reference numbers will be used throughout the drawings to refer to the same or like elements or structures, wherein: 1-plunger piston shoe component, 2-extrusion valve component, 3-suction valve component, 4-rear end cover, 5-cylinder body, 6-central pre-tightening spring, 7-central spring seat, 8-steel ball, 9-main shaft cushion block, 10-shell base, 11-cylindrical roller bearing, 12-shell, 13-self-aligning thrust roller bearing, 14-bearing seat, 15-cylindrical roller bearing, 16-main shaft, 17-self-aligning thrust roller bearing, 18-angular contact ball bearing, 19-stop washer, 20-round nut, 21-swash plate, 22-clearance adjusting ring, 23-return plate, 24-rear guide bearing, 25-plunger sealing component, 26-front guide bearing, 27-outlet flange, 28-damping screw plug, 29-hinged pipe joint, 30-water pipe, 31-ferrule type pipe joint, 32-heat-dissipation copper coil pipe, 33-coil pipe bracket, 34-hinged head assembly, 35-round nut, 36-stop washer, 37-plunger retainer ring, 38-plunger body, 39-ceramic plunger, 40-plunger ball head, 41-outer sliding shoe, 42-inner sliding shoe, 43-extrusion valve sleeve, 44-extrusion valve spring, 45-extrusion valve core, 46-extrusion valve seat, 47-suction valve seat, 48-suction valve core, 49-suction valve spring, 50-suction valve sleeve and 51-suction valve spring seat.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the utility model and are not intended to limit the utility model. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

The embodiment of the utility model provides a fixed clearance return type high-pressure plunger water pump, as shown in fig. 1, comprising a pump main body, a main shaft 16, a pre-tightening component, a swash plate 21, a return component, a plunger piston shoe component 1, a flow distribution component and a cooling component, wherein:

the pump main body comprises an outlet flange 27, a rear end cover 4, a cylinder body 5, a shell base 10, a shell 12 and a bearing seat 14 which are connected in sequence;

the main shaft 16 is rotatably installed in the pump main body, and is specifically connected with the shell base 10 and the bearing seat 14 through the cylindrical roller bearing 11 and the cylindrical roller bearing 15 respectively, the input end of the main shaft 16 extends out of the pump main body through a round hole in the center of the bearing seat 14, and a blind hole is machined in the center of the end face of the non-input end. An inclined bending section and an inclined shaft disc are processed in the middle section of the main shaft 16, and the inclined shaft disc can be subjected to larger axial force in the working process, so that a self-aligning thrust roller bearing 13 is arranged between the back surface of the inclined shaft disc and the bearing seat 14 to provide axial support, and the bearing also shares part of radial force for the cylindrical roller bearing 11 and the cylindrical roller bearing 15; that is, the radial force of the main shaft 16 is mainly borne by the cylindrical roller bearings respectively installed at the horizontal straight shaft sections at the two ends of the main shaft, and the axial force is borne by the self-aligning thrust roller bearing installed between the back surface of the main shaft inclined shaft disc and the bearing seat.

The pre-tightening assembly comprises a central pre-tightening spring 6, a central spring seat 7, a steel ball 8 and a main shaft cushion block 9, wherein the main shaft cushion block 9 and the steel ball 8 are sequentially arranged in a blind hole at the non-input end of the main shaft 16 from inside to outside; a stepped blind hole is machined in the center of the cylinder body 5, the central pre-tightening spring 6 and the central spring seat 7 are installed in the stepped blind hole from inside to outside, the central pre-tightening spring 6 which is compressed after installation sequentially passes through the central spring seat 7, the steel ball 8, the main shaft cushion block 9 and the main shaft 16 to apply axial pre-tightening force to the self-aligning thrust roller bearing 13, the axial pre-tightening force is only needed under the condition that the pump outlet is in no-load, and therefore the central pre-tightening spring force is small. Meanwhile, the steel ball 8, the main shaft cushion block 9 and the central spring seat 7 are in point contact, so that the friction resistance moment and the heat productivity generated in the working process are small.

The swash plate 21 is rotatably arranged on the main shaft, is particularly arranged on the inclined bending section through an angular contact ball bearing 18 and is arranged on the inclined surface of the inclined shaft disc through a self-aligning thrust roller bearing 17, and the working surface of the swash plate 21 is kept parallel to the inclined surface of the inclined shaft disc; after the angular contact ball bearing 18 is mounted on the main shaft, it is axially fixed by a round nut 20 and a stop washer 19, and a certain pre-tightening force is applied to the self-aligning thrust roller bearing 17.

The return assembly comprises a return disc 23 and a clearance adjusting ring 22, the return disc 23 is relatively fixedly connected to the swash plate 21 through screws, and the clearance adjusting ring 22 is installed between the return disc 23 and the swash plate 21 to enable a certain space to be reserved between the return disc 23 and the swash plate 21.

Further, the return disc 23 and the swash plate 21 are made of high-grade nitrided steel subjected to thermal refining and surface nitriding.

The number of the plunger piston shoe assemblies 1 is odd to reduce flow pulsation, and the plunger piston shoe assemblies 1 correspond to the cylinder body 5 and plunger cavities uniformly distributed on the shell base 10 in the circumferential direction one by one; the plunger piston shoe assembly comprises a plunger part and a piston shoe part, wherein the plunger part and a sealing assembly in a plunger cavity divide the inner space of the pump main body into a working medium cavity and a lubricating oil cavity, and the piston shoe part is kept in contact with the swash plate through a return assembly.

Specifically, as shown in fig. 2, the slipper component includes an outer slipper 41, an inner slipper 42 and a plunger ball head 40, wherein an inner sidewall surface of the outer slipper 41 in the direction close to the plunger component and a top of the inner slipper 42 are both spherical surfaces, and the plunger ball head 40 is assembled from the bottom of the outer slipper 41 and then the inner slipper 42 is assembled, thereby forming the slipper with the ball hinge. The inner shoes 42 have a through hole in the center to facilitate oil entering the friction pair for lubrication. The combined sliding shoes are arranged in circular holes uniformly distributed on the return disc 23 in the circumferential direction, and the diameter of the circular holes can meet the space requirement that the sliding shoes slide in a small-range radial direction relative to the swash plate in the working process.

Further, a flange is provided on the outer side of the outer shoe 41, and the flange is fitted into a gap between the return disc 23 and the swash plate 21 formed by the gap adjustment ring 22, and the height of the gap is 0.02mm to 0.05mm greater than the thickness of the flange of the outer shoe 41, so that the shoe can slide flexibly in the circular hole of the return disc 23 without being inclined.

Specifically, the plunger component comprises a plunger body 38 and a ceramic plunger 39, wherein one end of the plunger body 38 is connected with the plunger ball 40 through an internal thread, the other end of the plunger body is provided with an external thread and a shaft shoulder, and the peripheral surface of the plunger body is also provided with an annular groove for mounting a sealing ring; the ceramic plunger 39 is a cylindrical part with a length smaller than that of the plunger body 38 and is made of high-hardness, wear-resistant and corrosion-resistant engineering ceramic materials, and the ceramic plunger 39 is sleeved outside the plunger body 38 and is axially fixed on the plunger body 38 by means of the round nut 35, the stop washer 36 and the plunger retainer ring 37.

More specifically, a front guide bearing 26, a plunger sealing assembly 25 and a rear guide bearing 24 are sequentially arranged on the wall surface of the plunger cavity; the plunger component is arranged in the plunger cavity through the front guide bearing 26 and the rear guide bearing 24 and can slide along the axial direction; the outer surface of the ceramic plunger 39 contacts with the seal ring in the plunger seal assembly 25 to separate the water in the working medium chamber of the water pump from the oil in the lubricating oil chamber, i.e., the internal space of the pump body is separated into the working medium chamber and the lubricating oil chamber. A small amount of liquid leaked from the plunger sealing assembly 25 enters a pore channel arranged on the cylinder body 5 from the middle part of the plunger sealing assembly 25 and flows into the low-pressure cavity, and can be discharged out of the water pump through a pore channel structure different from that in the embodiment, so that the use requirements of different occasions are met.

The flow distribution assembly comprises a suction valve assembly 3 and a pressing valve assembly 2, and a pump inlet, a pump outlet, a cavity used for mounting the pressing valve assembly 2, a ring groove-shaped flow passage communicating the pump inlet with the suction valve inlet, and an inclined hole flow passage communicating the pump outlet with the pressing valve outlet are formed in the rear end cover 4. Correspondingly, the cylinder body 5 is provided with a hole cavity for mounting the suction valve component 3, a hole channel for communicating the plunger cavity with the inlet of the corresponding extrusion valve component 2, and a hole channel for communicating the plunger cavity with the outlet of the corresponding suction valve component 3. Namely, the suction valve component 3 is arranged in a flow passage between the pump inlet and the plunger cavity, and the extrusion valve component 2 is arranged in a flow passage between the plunger cavity and the pump outlet, so that the working medium cavity is sequentially divided into a low-pressure cavity, a working accommodating cavity and a high-pressure cavity.

Specifically, as shown in fig. 3 and 4, the suction valve assembly 3 includes a suction valve seat 47, a suction valve spool 48, a suction valve spring 49, a suction valve sleeve 50, and a suction valve spring seat 51, wherein the suction valve spring 49 presses the suction valve spool 48 against the suction valve seat 47 to close the suction passage; the inner wall of the suction valve sleeve 50 is processed into a stepped hole, and the middle part of the suction valve sleeve is symmetrically provided with an even number of rectangular windows, so that the processing is convenient, the outflow is symmetrical, and the lateral unbalanced force on the valve core is avoided; the rectangular window is communicated with the plunger cavity, the stepped hole of the suction valve sleeve 50 is communicated with the pump inlet, fluid sucked by the suction valve flows out to the plunger cavity through the rectangular window, and the suction valve spool 48 is installed in the large-diameter hole cavity of the stepped hole. The structure forms of the extrusion valve component 2 and the suction valve component 3 are basically the same, the extrusion valve component 2 comprises an extrusion valve seat 46, an extrusion valve core 45, an extrusion valve spring 44, an extrusion valve sleeve 43 and an extrusion valve spring seat, the extrusion valve spring seat is processed on the rear end cover 4, an extrusion valve window is communicated with an outlet of a pump, and an extrusion valve stepped hole is communicated with a plunger cavity.

Further, the diameter of the large diameter bore in the stepped bore is slightly larger than the outer diameter of the suction valve spool 48, thereby providing a guide function thereto and preventing inclination thereof; the distance between the end face of the suction valve spool 48 on the side where the suction valve spring 49 is installed and the stepped hole is slightly larger than the maximum opening of the suction valve spool 48 under the rated working condition, so that the suction valve spool 48 is prevented from being excessively lifted due to the action of inertia force when being quickly opened, the closing delay of the suction valve is further aggravated, and the volumetric efficiency of the water pump is reduced.

The cooling assembly comprises a damping screw plug 28, a water conveying pipeline, a heat dissipation copper coil pipe 32 and a drainage pipeline which are connected in sequence, wherein the damping screw plug 28 is arranged on the outlet flange 27, and a damping hole is formed in the damping screw plug 28, so that a pump outlet flow passage is communicated with the water conveying pipeline; the water conveying pipeline comprises a hinged pipe joint 29, a water conveying pipe 30, a ferrule type pipe joint 31 and a hinged joint assembly 34 which are sequentially connected, wherein the hinged joint assembly 34 penetrates through the bearing seat 14 to be connected and installed in the lubricating oil cavity, and the heat dissipation copper coil pipe 32 is supported and fixed by a coil pipe bracket 33; the heat-dissipating copper coil 32 is immersed in oil in the lubricating oil chamber; the structure and composition of the drainage pipeline are similar to those of the water conveying pipeline, so that the drainage pipeline is not described in detail, and the drainage pipeline can be connected to a water pumping end or directly discharges cooling water according to the use requirement.

The working process of the fixed clearance return type high-pressure plunger water pump is as follows: when the main shaft 16 rotates, the inclined bent section and the inclined shaft disc thereof force the swash plate 21 to swing, and the return disc 23 and the clearance adjusting ring 22 fixedly mounted on the swash plate 21 keep the slipper assembly in contact with the swash plate 21 all the time, so that the swinging of the swash plate 21 drives the plunger assembly to do axial reciprocating motion in the plunger cavity. When the spindle 16 is rotated to the position shown in fig. 1, the plunger shoe assembly 1 is in the extreme depressed position. As the spindle 16 continues to rotate, the return disc 23 pulls the plunger shoe assembly 1 to the right via the flange of the outer shoe 41, increasing the volume of the working volume at the top of the plunger assembly and decreasing the pressure. When the pressure drops sufficiently to overcome the force of the suction valve spring 49, the suction valve opens and water enters the cavity at the top of the plunger assembly from the pump inlet via the suction valve assembly 3, thereby effecting a suction event. When the main shaft 16 rotates 180 ° from the position of fig. 1, the water suction process of the plunger shoe assembly 1 is finished and extends to the limit position. Along with the continuous rotation of the main shaft, the swash plate pushes the plunger piston shoe assembly 1 to move leftwards, the volume of the working cavity is reduced, and the pressure rises. When the pressure is high enough to overcome the force of the pinch valve spring 44, the pinch valve opens and water from the working volume is drawn into the pump outlet via the orifice in the pinch valve assembly 2 and rear end cap 4, thereby effecting a drain. When the spindle 16 is rotated again by 180 °, the drainage of the plunger shoe assembly 1 is terminated and the pressing-in limit position is returned. The water suction and discharge operations are repeated independently and continuously by each plunger as the main shaft rotates, thereby outputting high-pressure water.

Simultaneously with the above working process, part of the fluid in the high-pressure cavity is depressurized through the damping hole on the damping screw plug 28 and then enters the heat-dissipating copper coil 32 through the water pipeline. The fluid absorbs part of the heat of the lubricating oil while flowing in the heat-dissipating copper coil 32, then flows out of the heat-dissipating copper coil 32, and then is converged into the low-pressure chamber or discharged out of the pump through the water discharge pipeline.

The fixed clearance return type high-pressure plunger pump designed by the utility model can improve the frictional wear and thermal wear of the existing oil-water separation type valve flow distribution plunger pump caused by the problems of higher PV value of a friction pair in the pump, poor connection strength of a plunger ball head and a sliding shoe, unreliable return device, poor heat dissipation capability of a lubricating oil cavity and the like, improves the working performance, working stability and reliability of the water pump, and is particularly suitable for medium-high pressure water hydraulic systems.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the utility model, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. The utility model provides a fixed clearance returns form high pressure plunger water pump which characterized in that, includes pump main part, main shaft (16), pretension subassembly, sloping cam plate (21), return stroke subassembly and plunger piston shoes subassembly, wherein:

the pump main body comprises a rear end cover (4), a cylinder body (5), a shell base (10), a shell (12) and a bearing seat (14) which are connected in sequence;

two ends of the main shaft (16) are respectively movably connected with the shell base (10) and the bearing seat (14); an inclined bending section and an inclined shaft disc are machined in the middle section of the main shaft (16), and a self-aligning thrust roller bearing is installed between the back face of the inclined shaft disc and the bearing seat (14);

the pre-tightening component is arranged at the non-input end of the main shaft (16) and is used for providing pre-tightening force for the self-aligning thrust roller bearing on the back of the inclined shaft disc;

the swash plate (21) is mounted on the inclined bent section through an angular contact ball bearing (18) and is mounted on the inclined surface of the swash plate through a thrust self-aligning roller bearing, and the working surface of the swash plate (21) is parallel to the inclined surface of the swash plate;

the return assembly comprises a return disc (23) and a clearance adjusting ring (22), the return disc (23) is fixedly connected to the swash plate (21), and the clearance adjusting ring (22) is installed between the return disc (23) and the swash plate (21);

the plunger piston shoe assembly comprises a plunger part and a piston shoe part, the plunger part is movably arranged in a plunger cavity formed in the cylinder body (5), and the piston shoe part is nested and arranged between the return disc (23) and the swash plate (21).

2. The fixed-gap return type high-pressure plunger water pump as claimed in claim 1, wherein the slipper component comprises an outer slipper (41), an inner slipper (42) and a plunger ball head (40), wherein the inner sidewall surface of the outer slipper (41) close to the direction of the plunger component and the top of the inner slipper (42) are both spherical surfaces, the plunger ball head (40) and the inner slipper (42) are both installed in the outer slipper (41), and the inner slipper (42) is matched with the plunger ball head (40) to form a slipper with a spherical hinge; the slipper shoes are arranged in circular holes which are uniformly distributed on the return disc (23) in the circumferential direction and are kept in contact with the swash plate (21); the center of the inner sliding shoe (42) is provided with a through hole so as to facilitate the entry of oil.

3. The fixed-clearance return-type high-pressure plunger water pump as claimed in claim 2, wherein a flange is provided on an outer side of the outer shoe (41) and is embedded in a gap between the return disc (23) and the swash plate (21) formed by the clearance adjusting ring (22), and a height of the gap is 0.02mm to 0.05mm greater than a thickness of the flange of the outer shoe (41).

4. The fixed-gap return high-pressure plunger water pump as claimed in claim 2, wherein the plunger component comprises a plunger body (38) and a ceramic plunger (39), one end of the plunger body (38) is connected with the plunger ball (40) through an internal thread, and the ceramic plunger (39) is sleeved outside the plunger body (38) and is axially fixed.

5. The fixed-gap return type high-pressure plunger water pump as claimed in claim 4, wherein a plurality of plunger cavities are uniformly distributed on the cylinder body (5) in the circumferential direction, and a front guide bearing (26), a plunger seal assembly (25) and a rear guide bearing (24) are sequentially mounted on the wall surface of each plunger cavity; the plunger component is arranged in the plunger cavity through the front guide bearing (26) and the rear guide bearing (24) and can slide along the axial direction; the outer surface of the ceramic plunger (39) is in contact with a sealing ring in the plunger sealing assembly (25) to divide the inner space of the pump main body into a working medium cavity and a lubricating oil cavity.

6. The fixed clearance return type high-pressure plunger water pump as claimed in claim 5, further comprising a suction valve assembly (3) and a pressing valve assembly (2), wherein the rear end cover (4) is provided with a pump inlet and a pump outlet; the suction valve assembly (3) is installed in a flow channel between the pump inlet and the plunger cavity, and the extrusion valve assembly (2) is installed in a flow channel between the plunger cavity and the pump outlet, so that the working medium cavity is sequentially divided into a low-pressure cavity, a working accommodating cavity and a high-pressure cavity.

7. The fixed-gap return type high-pressure plunger water pump as claimed in claim 6, wherein the suction valve assembly (3) comprises a suction valve seat (47), a suction valve housing (50) and a suction valve spool (48), wherein a stepped hole is formed in an inner wall of the suction valve housing (50), the suction valve spool (48) is installed in a large-diameter hole cavity in the stepped hole, and one end of the suction valve spool (48) is pressed against the suction valve seat (47) by a suction valve spring (49); and a window is formed in the middle of the suction valve sleeve (50), the window is communicated with the plunger cavity, and meanwhile, a stepped hole of the suction valve sleeve (50) is communicated with the pump inlet.

8. The fixed-clearance return type high-pressure plunger water pump as claimed in claim 7, wherein a diameter of the large-diameter bore in the stepped hole is larger than an outer diameter of the suction valve spool (48), and a distance between an end surface of the suction valve spool (48) on a side where the suction valve spring (49) is mounted and the stepped hole is larger than a maximum opening degree of the suction valve spool (48) in a rated operation.

9. The fixed-gap return type high-pressure plunger water pump as claimed in claim 1, wherein the pre-tightening assembly comprises a central pre-tightening spring (6), a central spring seat (7) and a steel ball (8), wherein the central pre-tightening spring (6) and the central spring seat (7) are installed in a central blind hole of the cylinder body (5) from inside to outside; the steel ball (8) is arranged at the non-input end of the main shaft (16) and is in contact with the central spring seat (7).

10. The fixed gap return type high-pressure plunger pump according to any one of claims 6 to 9, further comprising a cooling assembly, wherein the cooling assembly comprises a damping screw plug (28), a water delivery pipeline, a heat dissipation copper coil (32) and a water discharge pipeline which are connected in sequence, wherein the damping screw plug (28) is installed at the pump outlet, and is provided with a damping hole, so that a pump outlet flow channel is communicated with the water delivery pipeline; and the heat-radiating copper coil (32) is immersed in oil liquid in the lubricating oil cavity.