CN107288836B

CN107288836B - Axial plunger pump

Info

Publication number: CN107288836B
Application number: CN201710240375.9A
Authority: CN
Inventors: 朱焱炜
Original assignee: Wuhan Juweitian Digital Machinery Manufacturing Co Ltd
Current assignee: Wuhan Juweitian Digital Machinery Manufacturing Co Ltd
Priority date: 2016-04-13
Filing date: 2017-04-13
Publication date: 2020-03-17
Anticipated expiration: 2037-04-13
Also published as: CN107288836A; WO2017177936A1; CN207093295U; HK1244861A1; CN105756877A

Abstract

An axial plunger pump is provided, including a housing, an input main shaft rotatably installed in the housing and including a middle inclined bent section, a swash plate rotatably installed on the middle inclined bent section, a plurality of connecting rods having one ends hinged to the swash plate through ball heads and the other ends provided with plungers, and a cylinder block having cylinder holes into which the plungers are reciprocatably inserted, wherein the cylinder block is fixed with respect to the housing, the swash plate performs spatial spherical oscillation with the rotation of the input main shaft, wherein a center of a circle constituted by an intersection point of a main axis of the input main shaft and an axis of the middle inclined bent section, a spherical oscillation center of the swash plate, and centers of ball heads of the plurality of connecting rods coincides at an coincidence point (A). Through the multi-center coincidence, the unbalanced moment of the swash plate can be further counteracted, and the vibration and the noise of the whole axial plunger pump are further reduced.

Description

Axial plunger pump

Technical Field

The present invention relates to the field of axial piston pumps and in particular to an axial piston pump suitable for pumping low viscosity liquids such as fresh water or sea water.

Background

Plunger pumps are important devices for pumping fluids. The plunger reciprocates in the cylinder hole of the cylinder body, so that the volume of the sealed working cavity is changed to realize suction and ejection. The plunger pump has the advantages of high rated pressure, compact structure, high efficiency, convenient flow regulation and the like, and is widely applied to occasions with high pressure, large flow and flow needing regulation, such as hydraulic machines, engineering machinery and ships.

The plunger pump includes two representative forms of an axial plunger pump and a radial plunger pump, and the axial plunger pump is widely used due to advantages such as a small size.

A conventional axial piston pump includes a cylinder block, a piston reciprocating in the cylinder block, and a swash plate. One end of the plunger reciprocates within the cylinder block to suck or eject fluid, and the other end abuts against the swash plate, for example, via a shoe and slides on the swash plate in the circumferential direction thereof as the cylinder block rotates. Also, a variable displacement and pressure pump may be achieved by adjusting the angle of inclination of the swash plate.

This structure is effective for use with a fluid having a high viscosity, but when the fluid to be pressurized is a fluid such as water, the lubricating performance between the shoes and the swash plate is poor due to low viscosity of water, poor lubricity, etc., thereby limiting the inclination angle of the swash plate and, in turn, limiting the increase in the displacement and pressure of the pump.

To overcome this problem, in chinese patent application CN100362232C assigned to the present applicant, an axial piston pump suitable for pumping low viscosity fluids is proposed, in which the cylinder block is kept fixed with respect to the housing, the piston is mounted by means of a ball head on a swash plate, which is rotatably mounted on the bell crank of the rotating main shaft, whereby the swash plate drives the spherical surface of the piston to oscillate, thereby avoiding the problem of friction between the swash plate and the shoe of the piston. However, this solution has problems in that the rotating main shaft is supported by a cantilever, resulting in a large unbalanced moment, so that the swash plate has poor swing stability during operation, and the whole pump has large vibration, resulting in noise, friction, and the like.

In order to overcome such unbalanced moment, in chinese utility model patent CN201739111U assigned to the present applicant, the above-mentioned axial plunger pump is improved such that the rotary main shaft is supported at both ends, two sets of bearings are employed near the input end of the main shaft to enhance the support of the main shaft, and a guide slider is provided at the radial outside of the swash plate, which is fitted with guide grooves formed on the corresponding portion of the housing to guide the swing of the swash plate. However, the problems of large vibration, poor rotational stability, large noise and friction and the like of the plunger pump cannot be thoroughly solved by the scheme, and the friction between the guide sliding block and the guide sliding groove is increased, so that the service life of the whole pump is shortened. In addition, since the main shaft is supported at its input end by two sets of bearings and at the opposite end of the main shaft by an additional set of bearings, the main shaft suffers from over-constraint, thereby resulting in excessive stresses in the main shaft and reducing the life of the main shaft and thus the overall pump.

Both of the above patents are incorporated herein by reference in their entirety.

Therefore, there is still a need for further improvements of such axial piston pumps.

Disclosure of Invention

The present invention has been made to solve the above problems. It is an object of the present invention to provide an axial piston pump which is particularly suitable for pumping low viscosity fluids, such as seawater or fresh water, and which may have well balanced characteristics, reducing pump vibration and noise, and increasing pump life.

According to an aspect of the present invention, there is provided an axial plunger pump including a housing, an input main shaft rotatably installed in the housing and including an intermediate obliquely bent section, a swash plate rotatably installed on the intermediate obliquely bent section, a plurality of connecting rods having one end hinged to the swash plate through a ball head and the other end provided with a plunger, and a cylinder block having a cylinder hole into which the plunger is reciprocatably inserted, wherein the cylinder block is fixed with respect to the housing, the swash plate performs a spatial spherical swing in accordance with rotation of the input main shaft, and wherein the input main shaft further includes a first straight line section rotatably supported on the housing through a bearing, and a balance ring is further provided on the first straight line section, the balance ring being an eccentric structure and rotating together with the input main shaft.

Through the balance ring with the eccentric structure, the unbalanced moment of the swash plate can be further counteracted, and the vibration and noise of the whole axial plunger pump are further reduced.

Advantageously, the center of a circle formed by the intersection of the axis of the first straight line segment of the input spindle and the axis of the intermediate oblique curved segment, the spherical swing center of the swash plate, and the centers of the spherical heads of the plurality of links coincides with a coincidence point (a).

By making the intersection point, the swing center and the circle center coincide, the unbalanced moment when the swash plate does the space spherical swing can be offset, and the vibration and the noise of the whole axial plunger pump are reduced.

Advantageously, the swash plate rotation limiting device further comprises a swash plate rotation limiting ring, wherein the swash plate rotation limiting ring is connected with the swash plate in a relatively rotatable mode through a connecting shaft, and the swash plate rotation limiting ring is connected with the shell through a pin shaft which is arranged in a radially opposite mode, so that the swash plate rotation limiting ring can swing around the pin shaft relative to the shell.

And the intersection point of the axis of the connecting shaft of the swash plate rotation limiting ring and the axis of the pin shaft is superposed with the superposed point.

The intersection point of the swash plate rotation limiting ring is coincided with the coincidence point, so that the unbalanced moment of the swash plate can be further counteracted, and the vibration and the noise of the whole axial plunger pump are further reduced.

Advantageously, the valve further comprises a distributing valve comprising a valve seat and a suction valve spool and a discharge valve spool mounted in the valve seat, the suction valve spool and the discharge valve spool being biased towards the valve seat respectively, wherein the spools are made of a corrosion resistant high strength lightweight material, such as titanium alloy.

By using a high-strength lightweight material that is corrosion resistant, the valve cartridge can resist corrosion such as seawater, and can be reduced in weight, thereby reducing the moment of inertia of the valve cartridge.

Advantageously, an annular gap, for example not less than 0.5 mm, is formed between the outer peripheral surface of each of the spools and the corresponding mating surface of the valve seat. In addition, a second gap, for example between 0.3 and 0.4 mm, is formed between the valve seat and the mating element.

By providing the annular gap and the second gap, the impact inertia of the valve element during reciprocating motion can be reduced. Therefore, the working reliability, the corrosion resistance and the medium adaptability of the distributing valve are improved, and the vibration and the noise of the distributing valve and the axial plunger pump during working are reduced.

Drawings

The above and other features, advantages and technical advantages of the present invention will be understood by reference to the following detailed description of a preferred embodiment of the invention with reference to the accompanying drawings, in which:

fig. 1 is a main sectional view showing an axial plunger pump according to an embodiment of the present invention;

FIG. 2 is a partial cross-sectional view showing a swash plate portion of the axial piston pump shown in FIG. 1;

FIG. 3 is a cross-sectional view showing a swash plate rotation restricting ring;

fig. 4 is a sectional view showing a configuration of a valve block;

FIG. 5 is a perspective view showing the input spindle and a gimbal mounted thereon;

fig. 6 is a cross-sectional view of fig. 5.

Detailed Description

Preferred embodiments according to the present invention are described in detail below with reference to the accompanying drawings. It is noted that the description is intended for purposes of illustration only and not for limitation, and that those skilled in the art will recognize that the invention can be embodied in many forms and should not be construed as limited to the preferred embodiments set forth herein.

In the following description, it is noted that descriptions about directions, such as an outer side, an inner side, an upper side or a lower side, are made with reference to directions shown in the drawings for convenience of explanation and explanation, but the present invention is not limited thereto, and may be changed according to a specific application or installation position of the described component or device.

Fig. 1 shows a main sectional view of an axial piston pump according to an embodiment of the invention. As shown in fig. 1, an axial plunger pump (hereinafter simply referred to as a pump) includes a housing 1, and an input main shaft 2 is rotatably supported on the housing 1 by

bearings

31 and 32. Specifically, as shown in fig. 2 and 3, the input spindle 2 includes a first straight line segment 21, an intermediate oblique-bent segment 22, and a second straight line segment 23, the first straight line segment 21 and the second straight line segment 23 being in a straight line, and the intermediate oblique-bent segment 22 being integrally provided between the first straight line segment 21 and the second straight line segment 23. As shown in fig. 3, the axis of the intermediate angled section 22 is at an angle of 15 to 40 degrees to the axis of the first and second

straight sections

21 and 22, which can vary depending on the desired flow rate and pressure of the pump.

The first linear section 21 of the input spindle 2 is supported on the housing 1, for example on the end cap 11 of the housing 1, by means of bearings 31, for example ball bearings. The invention is not limited thereto and other types of bearings may be used. At the same time, the second straight section 23 of the input spindle 2 is also supported on the housing 1 by means of a further bearing 32 (also for example a ball bearing).

The intermediate oblique-bent section 22 may for example comprise two different diameter portions, and the swash plate 5 is rotatably mounted on the intermediate oblique-bent section 22, for example by means of two tapered roller bearings 33 of different specifications.

As shown in fig. 5 and 6, a gimbal 25 is mounted on the first linear segment 21 of the input spindle 2, for example, by a key 24, so that the input spindle 2 and the gimbal 25 can rotate together. The balance ring 25 comprises an axial portion 251 and a radial portion 252, the axial portion 251 being fitted over the first straight section 21 of the input spindle 2, and the inner ring of the first bearing 3 being able to be fitted over the outer circumference of this axial portion 251. The radial portion 252 of the balance ring 25 is eccentrically shaped to counteract the imbalance caused by the intermediate skew 22 on the input spindle 2 and the swashplate mounted on the intermediate skew 22 during rotation of the input spindle 2.

The swash plate 5 of the axial piston pump is described below with reference to fig. 2 and 3. As described above, the swash plate 5 is supported on the intermediate slant-bent section 22 of the input spindle 2 by the two tapered roller bearings 33 such that the swash plate 5 is inclined at an angle of 15 to 40 degrees with respect to the axis of the input spindle 2. The swash plate 5 includes a swash plate body 51 and a swash plate cover 52, and the swash plate body 51 and the swash plate cover 52 are connected together by, for example, screws. The swash plate body 51 and the swash plate gland 52 are respectively formed with a plurality of cavities at equal intervals in the circumferential direction, so that when the swash plate body 51 and the swash plate gland 52 are assembled together, the corresponding cavities are spliced into a ball head cavity, and the ball head 71 of the connecting rod is accommodated in each ball head cavity.

For each ball head chamber, as shown in fig. 2, for example, the cavity formed in the swash plate body 51 is a concave cavity, and the cavity formed in the swash plate cover 52 is a through cavity formed with a flare 512 on an end toward the cylinder block. The concave cavity and the through cavity are spliced to form a ball head cavity. Additionally, the recessed cavity and the through cavity are lined with

blocks

513 and 523, respectively, made of copper or the like, the

blocks

513 and 523 cooperating to form a spherical cavity that closely surrounds the ball head 71 of the connecting rod, forming a ball-and-socket joint with the ball head 71 to allow spherical rotational movement of the ball head 71 therein.

Through set up solitary cushion in the bulb intracavity come to form the ball pivot cooperation with bulb 71, directly form the ball pivot cooperation with the sloping cam plate material with bulb 71 and compare, can reduce bulb 71's friction to can change easily when the cushion is worn and torn, reduced the maintenance cost.

Furthermore, in order to compensate for the unbalanced moment of the swash plate 5 during operation, a swash plate rotation limiting ring 8 is provided on the outer circumferential side of the swash plate 5, which swash plate rotation limiting ring 8 is connected to the swash plate 5, for example, by a connecting shaft 81, so that the swash plate rotation limiting ring 8 and the swash plate 5 can rotate relative to each other about the axis of the connecting shaft 81, and on the other hand, as shown in fig. 3, the swash plate rotation limiting ring 8 is rotatably connected to the housing 1 of the plunger pump by two opposing pins 82. The pin shaft 82 is different from the connecting shaft 81 by approximately 90 degrees in the circumferential direction. The specific structure of the swash plate rotation-limiting ring 8 is described in chinese utility model patent CN201739163U, which is hereby incorporated by reference in its entirety.

In addition, in order to further eliminate the unbalanced moment caused by the rotation of the swash plate 5, the input main shaft 2, the swash plate 5 and the swash plate rotation limiting ring 8 are further configured such that the intersection point of the axis of the input main shaft 2 passing through the first straight line section 21 and the second straight line section 23 and the axis of the middle inclined bent section 22, the center of spherical swing of the swash plate, the center of a circle formed by the center of each plunger ball 71, and the intersection point of the pin shaft 82 of the swash plate rotation limiting ring 8 and the connecting shaft 81 connecting the swash plate rotation limiting ring and the swash plate coincide at one point, which is marked by a in the figure and is called as a coincidence point, and is hereinafter referred to as four-center coincidence.

With continued reference to fig. 1, the axial piston pump according to the invention comprises a plurality of connecting rods 7, each connecting rod 7 being in ball-joint engagement with the swash plate 5 via a ball head 71 at one end and being connected to the piston 4 at its other end. The plunger 4 is inserted into a corresponding cylinder hole 101 in the cylinder 10 to reciprocate in the cylinder hole 101 by the rod 7. The cylinder 10 is fixed relative to the housing.

Referring to fig. 4, a port valve 9 is further provided in the housing 1, the port valve 9 selectively communicating a port plate passage leading to a cylinder hole 101 of the cylinder block with a suction passage and a discharge passage of the plunger pump. The distributing valve includes a valve seat 91, a suction valve spool 92, a suction valve spring 93, a discharge valve spool 94, and a discharge valve spring 95. A suction valve spring 93 biases the suction valve spool 92 against the valve seat 91 to close the suction passage 96 of the pump, and a discharge valve spring 95 biases the discharge valve spool 94 against the valve seat 91 to close the discharge passage 97 of the pump.

The suction valve spool and the discharge valve spool may be made of a corrosion-resistant, high-strength, lightweight material, such as titanium alloy, to reduce the weight thereof, thereby reducing the motion inertia of the spools.

As shown in fig. 4, the suction valve spool 92 and the discharge valve spool 94 are respectively installed such that an annular gap G1 between the outer peripheral surface of the spool and the inner peripheral surface of the mating part is not less than 0.5 mm, for example, so that the frictional resistance of the spool at the time of rapid movement is reduced. Further, the valve seat 91 and the housing are sealed by a seal ring. After the valve is assembled into the housing, a gap G2 is formed between the valve seat and a mating member, which may include a housing or valve sleeve. The gap G2 is, for example, between 0.3 and 0.4 mm, and is used to reduce the impact inertia of the spool during reciprocation, thereby reducing noise.

The operation of the axial piston pump according to the invention is briefly described below.

In operation of the axial piston pump according to the invention, a power source, for example an electric motor (not shown), is activated so that an input rotation is imparted to the axial piston pump.

Under the drive of the motor, an input main shaft 2 of the axial plunger pump rotates relative to the shell 1, and under the combined action of the input main shaft, a supporting bearing, a swash plate supporting bearing and a swash plate rotating limiting ring, a swash plate 5 arranged on the middle inclined bending section 22 does not rotate but does spatial spherical swing around a coincidence point A. And the swing unbalance of the swash plate is effectively cancelled out due to the action of the balance ring and the swash plate rotation-limiting ring mounted on the first straight line segment 21 of the input spindle 2 and due to the above-described four-center coincidence.

The spherical swing of the swash plate 5 drives the connecting rod and the plunger 4 to reciprocate in the cylinder hole 101 of the cylinder block 10, and it is noted that the interference between the ball head cavity of the swash plate and the ball head and the connecting rod during the spherical swing of the swash plate 5 can be avoided due to the existence of the flared opening 512.

As further shown in fig. 4, when the plunger is stationary, a sealed space is formed between the cylinder bore and the front end of the plunger and the suction valve due to the biasing action of the suction valve spring and the discharge valve spring. When the plunger moves upward, a vacuum is formed in the sealed space, and when the pressure difference across the suction valve spool 92 is greater than the biasing force of the suction valve spring 93, the suction valve spool 92 is moved rightward against the force of the suction valve spring 93, thereby opening a suction passage and sucking a working medium, such as water. When the plunger moves downward, the pressure in the sealed space increases so that the suction valve spool 92 is quickly closed, at which time the increased pressure opens the discharge valve spool 93 against the biasing force of the discharge valve spring 94, thereby discharging the medium in the cylinder bore. The axial plunger pump sucks in the medium, pressurizes the medium and discharges the medium in a reciprocating mode.

In the invention, by arranging the balance ring on the first straight line segment of the input main shaft and configuring the swash plate and other components to be overlapped in four centers, unbalanced moment in the movement process of the swash plate can be counteracted, so that the axial plunger pump according to the invention can work more stably, the working noise is reduced, and the abrasion of equipment is reduced. Therefore, the requirement that two groups of bearings are arranged on the first straight line segment of the input main shaft in the prior art is eliminated, and the problem of over-constraint of the input main shaft is solved.

In the invention, the valve seat and the pump body are kept in a gap, so that the impact inertia of the valve core during reciprocating motion is reduced, the distribution valve is reliable in operation, strong in medium adaptability and small in noise and vibration during operation.

While the above is a detailed description of the preferred embodiments of the invention, various modifications and changes will be apparent to those skilled in the art in view of the above description. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the scope of the invention be limited only by the appended claims and equivalents thereof.

Claims

1. An axial piston pump comprising:

a housing;

an input spindle rotatably mounted in the housing and including a central skew section;

a swash plate rotatably mounted on the intermediate skew section;

the swash plate rotation limiting ring is connected with the swash plate in a relatively rotatable manner through a connecting shaft and is connected with the shell through a pin shaft which is arranged in a radially opposite manner, so that the swash plate rotation limiting ring can swing relative to the shell around the pin shaft;

a plurality of connecting rods, one end of which is hinged to the swash plate through a ball head, and the other end of which is provided with a plunger;

a cylinder block having a cylinder hole into which a plunger is reciprocatably inserted; and

a flow distribution valve including a valve seat and a suction valve spool and a discharge valve spool installed in the valve seat, the suction valve spool and the discharge valve spool being biased toward the valve seat, respectively,

wherein the cylinder block is fixed relative to the housing, the middle oblique bending section comprises two parts with different diameters, the swash plate is rotatably mounted on the middle oblique bending section through two tapered roller bearings with different specifications and does spatial spherical swing along with the rotation of the input main shaft, wherein the center of a circle formed by the intersection point of the main axis of the input main shaft and the axis of the middle oblique bending section, the spherical swing center of the swash plate, the intersection point of the axis of a pin shaft of the swash plate rotation limiting ring and the axis of a connecting shaft connecting the swash plate rotation limiting ring and the swash plate, and the centers of the ball heads of the plurality of connecting rods is coincided at a coincidence point (A),

wherein the input spindle further comprises a first linear section and a second linear section, the intermediate canted section being disposed between the first and second linear sections, the first linear section being supported on the housing by one bearing and the second linear section being supported on the housing by another bearing such that the input spindle is rotatably supported within the housing by two bearings;

wherein the first linear section comprises a balance ring, the balance ring being an eccentric structure and rotating together with the input spindle;

wherein annular gaps are formed between outer peripheral surfaces of the suction valve spool and the discharge valve spool and corresponding mating surfaces of the valve seat; and is

Wherein an axial second gap is formed between the valve seat and the mating element.

2. The axial piston pump as recited in claim 1 wherein said swash plate is formed with a ball cavity, the ball of each of said connecting rods being received in said ball cavity to form a ball-and-socket joint.

3. The axial plunger pump of claim 2, wherein the opening of the ball cavity is formed with a flare.

4. The axial piston pump as recited in claim 3, wherein the swash plate includes a swash plate body having a plurality of recessed cavities formed therein and a swash plate gland having a corresponding plurality of through cavities formed therein such that each of the recessed cavities forms the ball head cavity with a corresponding one of the through cavities when the swash plate body is mated with the swash plate gland.

5. The axial plunger pump of claim 4, wherein the flare is formed at an end of the through cavity facing the cylinder.

6. The axial plunger pump of claim 4, wherein a spacer is received in the ball head cavity, the spacer mating with the ball head to form a ball-and-socket joint.

7. The axial piston pump of claim 6, wherein the spacer is made of copper.

8. The axial piston pump as recited in claim 1, wherein the balancing ring includes an axial portion non-rotatably mounted on the first straight line segment such that the balancing ring rotates with the input shaft, and a radial portion that is eccentrically shaped.

9. The axial piston pump as recited in claim 8 wherein said balance ring and said first linear section of said input main shaft are rotatably supported on said housing by said one bearing.

10. The axial plunger pump of claim 1, wherein the axis of the intermediate beveled section is angled 15 to 40 degrees relative to the axis of the first and second linear sections.

11. The axial plunger pump of claim 1, wherein the suction valve spool and the discharge valve spool are made of a corrosion resistant, high strength, lightweight material.

12. The axial plunger pump of claim 11, wherein the high strength lightweight material is a titanium alloy.

13. The axial plunger pump of claim 1, wherein the annular gap is not less than 0.5 millimeters.

14. The axial plunger pump of claim 1, wherein the second gap is between 0.3 and 0.4 millimeters.