CN220353990U

CN220353990U - Power control valve and hydraulic pump

Info

Publication number: CN220353990U
Application number: CN202321793829.2U
Authority: CN
Inventors: 陈秀梅; 崔凯; 孙配芳; 巴一庆
Original assignee: Weichai Hydraulic Transmission Co ltd; Weichai Power Co Ltd
Current assignee: Weichai Hydraulic Transmission Co ltd; Weichai Power Co Ltd
Priority date: 2023-07-10
Filing date: 2023-07-10
Publication date: 2024-01-16
Anticipated expiration: 2033-07-10

Abstract

The utility model relates to the technical field of swash plate axial piston pumps, and in particular to a power control valve and a hydraulic pump. The power control valve is installed on the swash plate type axial piston pump, the piston pump is provided with a ball head, the piston pump housing forms a piston chamber, the power control valve includes a valve seat and a valve stem; The valve seat is installed at the end of the piston chamber of the plunger pump. The valve rod is slidingly connected to the valve seat. A piston is provided at the end of the valve rod. The piston is installed in the piston chamber and can move along the piston chamber. When moving in the axial direction, the end surface of the piston is a spherical surface, and the spherical surface is in contact with the ball head. The utility model improves the assembly efficiency and avoids the stuck problem when the piston is not coaxial with the center of the cavity and is tilted when moving in the cavity.

Description

Power control valve and hydraulic pump

Technical Field

The utility model relates to the technical field of swash plate type axial plunger pumps, in particular to a power control valve and a hydraulic pump.

Background

The swash plate type axial plunger pump is a fluid conveying mechanical device formed by axially and transversely moving a plunger in a fixed cylinder body, and is structurally characterized in that one side of a pump body is an inlet, the other side of the pump body is an outlet, a pump chamber is formed in an annular groove by combining a driving device, and conveying kinetic energy can be formed when low pressure and high pressure change is generated in the pump chamber, so that the purpose of conveying fluid is achieved.

The traditional swash plate type axial plunger pump has single function, the main pump can only work under a single working condition of constant power and constant pressure, and the main pump does not work under a working condition all the time when the main engine works, so that the large power loss and the energy waste are caused. For this purpose, the maximum displacement of the pump is generally defined by a power control valve, which effects the power regulation of the pump.

However, the front end structure of the existing power control valve is complex, the assembly efficiency is low, and faults are easy to occur. In addition, the front end face of the power control valve is of a plane structure and directly abuts against the ball head plane of the swash plate, so that the problem of inclined clamping stagnation is caused when the piston moves in the cavity and is not coaxial with the center of the cavity hole.

Disclosure of Invention

Aiming at the defects existing in the prior art, the embodiment of the utility model aims to provide a power control valve so as to solve the problems of complex structure and clamping stagnation of the existing power control valve.

In order to achieve the above object, the embodiment of the present utility model provides the following technical solutions:

a power control valve for mounting on a swash plate type axial plunger pump having a ball disposed therein, the plunger pump housing defining a piston chamber, the power control valve comprising: a valve seat and a valve stem; the valve seat is arranged at the end part of a piston cavity of the plunger pump, the valve rod is in sliding connection with the valve seat, a piston is arranged at the end part of the valve rod, the piston is arranged in the piston cavity and can axially move along the piston cavity, the end surface of the piston is a spherical surface, and the spherical surface is abutted to the ball head.

Preferably, the piston end has a conical surface, which is in transitional connection with the spherical surface.

Preferably, the outer wall of the piston is in sealing connection with the inner wall of the piston cavity through a first steel ring, and the part of the valve seat inserted into the piston cavity is in sealing connection with the sealing cavity through a second steel ring.

Preferably, the first steel ring is a rectangular ring or a plunger ring, and the second steel ring is a rectangular ring or a plunger ring.

Preferably, the first end of the valve seat is connected with the plunger pump in a threaded insertion mode, and the second end of the valve seat is detachably connected with a shell.

Preferably, a valve sleeve is arranged in the valve seat, the valve sleeve is in sliding connection with the valve seat, the valve rod further comprises a valve core, the valve core is connected with the piston, and the valve core is inserted in the valve sleeve.

Preferably, the end part of the piston is provided with a one-way valve, the one-way valve comprises a plug, a spring and a steel ball, the plug is arranged at the end part of the piston, one end of the piston is propped against the plug, the other end of the piston is propped against the steel ball, a through hole is formed in the valve core, and the steel ball is blocked at the through hole.

Preferably, a thread bush is arranged in the shell, the thread bush is connected with the valve core, a first nut is arranged outside the thread bush, a first spring seat is arranged at the end part of the valve sleeve, a second spring seat is arranged on the thread bush, a first spring is arranged between the outer wall of the first spring seat and the first nut, and a second spring is arranged between the inner wall of the first spring seat and the second spring seat.

Preferably, an adjusting rod is further inserted into the tail end of the threaded sleeve matched with the valve core, and the adjusting rod is adjusted through a second nut positioned on the adjusting rod.

The embodiment of the utility model also provides a hydraulic pump, which comprises the power control valve.

One or more technical solutions provided in the embodiments of the present utility model at least have the following technical effects or advantages:

the utility model improves on the basis of the existing control valve, changes the complex structure of the front end into a piston head design, has simpler structure, is convenient to install and improves the assembly efficiency. And the piston head is a spherical surface or a conical surface plus a spherical surface, so that the problem of clamping stagnation when the piston is inclined when the piston moves in the cavity and is not coaxial with the center of the cavity hole is avoided.

Additional aspects of the utility model will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the utility model.

In order to make the above objects, features and advantages of the present utility model more comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

The accompanying drawings, which are included to provide a further understanding of the utility model and are incorporated in and constitute a part of this specification, illustrate embodiments of the utility model and together with the description serve to explain the utility model.

FIG. 1 is a schematic illustration of a power control valve according to an embodiment of the present utility model mounted on a plunger pump;

FIG. 2 is a hydraulic schematic diagram provided by an embodiment of the present utility model;

in the figure: 1. a swash plate; 2. ball head; 3. a one-way valve; 4. a piston; 5. a first steel ring; 6. a second steel ring; 7. a valve sleeve; 8. a valve seat; 9. a first spring seat; 10. a first spring; 11. a second spring seat; 12. a second spring; 13. a thread sleeve; 14. a first nut; 15. a second nut; 16. an adjusting rod; 17. a housing; 20. a power control valve; 21. a pressure cut-off valve;

the mutual spacing or dimensions are exaggerated for the purpose of showing the positions of the various parts, and the schematic illustrations are used for illustration only.

Detailed Description

It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the utility model. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present utility model. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the utility model clearly indicates otherwise, and it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.

As shown in fig. 1, in one embodiment of the present utility model, a power control valve 20 is provided for being mounted on a swash plate type axial plunger pump, in which a swash plate 1 is disposed, a ball head 2 is disposed on the swash plate 1, and a piston chamber is formed on a pump housing of the plunger pump, and the piston chamber is disposed toward the ball head 2. The power control valve 20 comprises a valve seat 8 and a valve stem; the valve seat 8 is arranged at the end part of a piston cavity of the plunger pump, the valve rod is in sliding connection with the valve seat 8, the end part of the valve rod is provided with a piston 4, the piston 4 is arranged in the piston cavity and can axially move along the piston cavity, the end surface of the piston 4 is a spherical surface, and the spherical surface is abutted to the ball head 2. Further, the end part of the piston 4 is provided with a conical surface, and the conical surface is in transitional connection with the spherical surface.

The utility model improves on the basis of the existing control valve, changes the complex structure of the front end into the design of the head of the piston 4, has simpler structure, is convenient to install and improves the assembly efficiency. And the head of the piston 4 is a spherical surface or a conical surface plus a spherical surface, so that the problem of clamping stagnation when the piston 4 is inclined when the piston moves in the cavity and is not coaxial with the center of the cavity hole is avoided.

The outer wall of the piston 4 is in sealing connection with the inner wall of the piston cavity through a first steel ring 5, and the part of the valve seat 8 inserted into the piston cavity is in sealing connection with the sealing cavity through a second steel ring 6. The first steel ring 5 and the second steel ring 6 are rectangular rings or plunger rings; preferably, a plunger ring is used. The first steel ring 5 and the second steel ring 6 play a role in sealing, and the plunger ring plays a better role in sealing.

As shown in fig. 1, the lower left end of the valve seat 8 is connected with the plunger pump in a threaded insertion manner, the upper right end of the valve seat 8 is in threaded connection with a housing 17, and a containing cavity is formed between the housing 17 and the valve seat 8. The valve seat 8 is internally provided with a valve sleeve 7, the valve sleeve 7 is in sliding connection with the valve seat 8, the valve seat 8 is inserted into the pipe wall of one end of the piston cavity and is provided with an oil port, a P port, a PA port and a Pst port sequentially from left to right, the valve rod further comprises a valve core, the valve core is connected with the piston 4, and the valve core is inserted into the valve sleeve 7.

The end part of the piston 4 is provided with a one-way valve 3, the one-way valve 3 comprises a plug, a spring and a steel ball, the plug is arranged at the end part of the piston 4, one end of the piston 4 is propped against the plug, the other end of the piston is propped against the steel ball, a through hole is formed in the valve core, and the steel ball is blocked at the through hole.

The housing 17 is provided with a thread bush 13 in the accommodating cavity, the thread bush 13 is connected with the valve core, a first nut 14 is arranged outside the thread bush 13, a first spring seat 9 is arranged at the end part of the valve sleeve 7, a second spring seat 11 is arranged on the thread bush 13, a first spring 10 (namely an inner ring spring) is arranged between the outer wall of the first spring seat 9 and the first nut 14, and a second spring 12 (namely an outer ring spring) is arranged between the inner wall of the first spring seat 9 and the second spring seat 11. An adjusting rod 16 is further inserted into the end, matched with the valve core, of the threaded sleeve 13, and the adjusting rod 16 is adjusted through a second nut 15 located on the adjusting rod 16.

Control process of the power control valve 20:

(1) In the initial state, the piston 4 is attached to the valve seat 8 under the action of the spring force of the second spring 12, at the moment, the power control valve 20 works at the right position under the action of the spring force, the PA port is communicated with the T port, the piston cavity is pressureless, and the plunger pump has maximum displacement;

(2) When the power of the pump reaches a set value, the P port is communicated with the PA port, the pressure of a piston cavity is gradually increased, the inclination angle of the swash plate 1 is pushed to be reduced, the displacement of the pump is reduced, the piston 4 moves and simultaneously compresses the second spring 12 through the valve core and the thread sleeve 13, so that the valve sleeve 7 moves leftwards, the P port and the PA port are gradually closed, and the power of the pump is kept unchanged; when the pump outlet pressure P gradually decreases, the PA port and the T port are gradually conducted, the servo piston cavity is depressurized, the displacement of the pump is increased, and the power of the pump is kept unchanged;

(3) Electric proportional variable power regulation: when the pressure at the Pst port (the pilot pressure is 0-35 bar), the power of the pump is a set value, the current of the proportional reducing valve is increased, the pressure at the Pst port is increased along with the increase of the current, when the pressure at the Pst port is increased, the hydraulic pressure acting on the left side of the valve sleeve 7 is also increased, and the hydraulic acting force compensates part of the spring force at the right side of the valve sleeve 7, so that the power starting point pressure of the power control valve 20 is reduced, the set power of the pump is reduced, and the set power of the pump is reduced more when the pressure at the Pst port is higher, so that the proportional adjustment of the power of the pump in a certain range can be realized.

Therefore, through the spherical cooperation of the control piston 4 and the ball head 2, the rotation angle increase of the swash plate 1 can drive the control piston 4 to move upwards, when the control piston 4 moves upwards to the maximum rotation angle of the swash plate 1, high-pressure oil can be fed back according to the pressure difference, the high-pressure oil (the oil is the high-pressure outlet oil of the pump and is introduced through the oil passage of the shell and the oil passage on the valve seat 8) fills the control piston cavity, and the control piston 4 is pushed to move downwards until the swash plate 1 returns to the minimum displacement position so as to realize pump power control.

The power control valve 20 of the present utility model limits the input torque and the use of the power control valve 20 effectively prevents damage to the prime mover from excessive loads. The power control valve 20 can limit the maximum displacement of the pump, avoid mechanical damage caused by overlarge rotation angle of the swash plate 1, and improve the durability and reliability of the whole pump.

The torque limiting module overcomes the thrust of the valve core generated by the system pressure by two springs, and can set proper input torque through adjusting nuts of the inner spring and the outer spring, so that the torque limiting module is convenient to adjust according to specific working conditions.

Based on the above power control valve 20, the present utility model also proposes a hydraulic pump, a load sensitive pressure cut-off hydraulic pump with overload protection function, as shown in fig. 2, which includes the power control valve 20 and the pressure cut-off valve 21 and LS valve (feedback valve), mainly related to the functions of load sensing and pressure cut-off.

The load sensitive regulator is a flow control selector that operates as a function of load pressure to adjust pump displacement based on actuator flow demand. The load sensing control compares the pressures before and after sensing the orifice and maintains the pressure drop across the orifice (differential pressure Δp, Δp=pp-PL), thereby maintaining the pump flow constant.

If the differential pressure Δp at the sensing orifice increases, the pump displacement decreases. And if the pressure differential Δp decreases, the pump displacement increases until the pressure drop across the sensing orifice within the valve recovers.

When the pressure setting is reached, the pressure is shut off corresponding to pressure control that adjusts the pump displacement back to the minimum Vmin.

The DR control is based on the L1 control, and the spring side adjusting screw of the load sensitive valve is mechanically screwed down to make the load sensitive valve not function.

While the foregoing description of the embodiments of the present utility model has been presented in conjunction with the drawings, it should be understood that it is not intended to limit the scope of the utility model, but rather, it is intended to cover all modifications or variations within the scope of the utility model as defined by the claims of the present utility model.

Claims

1. The utility model provides a power control valve installs on sloping cam type axial plunger pump, be provided with the bulb in the plunger pump, the plunger pump shell forms a piston chamber, its characterized in that, power control valve includes: a valve seat and a valve stem;

the valve seat is arranged at the end part of a piston cavity of the plunger pump, the valve rod is in sliding connection with the valve seat, a piston is arranged at the end part of the valve rod, the piston is arranged in the piston cavity and can axially move along the piston cavity, the end surface of the piston is a spherical surface, and the spherical surface is abutted to the ball head.

2. The power control valve of claim 1, wherein said piston end has a conical surface that transitions with said spherical surface.

3. The power control valve of claim 1, wherein the piston outer wall is sealingly connected to the piston chamber inner wall by a first steel ring, and the portion of the valve seat inserted into the piston chamber inner wall is sealingly connected to the piston chamber by a second steel ring.

4. A power control valve according to claim 3, wherein the first steel ring is a rectangular ring or a plunger ring and the second steel ring is a rectangular ring or a plunger ring.

5. The power control valve of claim 1, wherein said valve seat first end is threadably connected to said plunger pump and said valve seat second end is removably connected to a housing.

6. The power control valve of claim 5, wherein a valve sleeve is disposed within the valve seat, the valve sleeve being slidably coupled to the valve seat, the valve stem further comprising a valve cartridge coupled to the piston, the valve cartridge being inserted within the valve sleeve.

7. The power control valve of claim 6, wherein the piston end is provided with a one-way valve comprising a plug, a spring and a steel ball, the plug being provided at the piston end, one end of the piston being abutted against the plug and the other end being abutted against the steel ball, a through hole being provided in the valve core, the steel ball being blocked at the through hole.

8. The power control valve of claim 6, wherein a threaded sleeve is disposed within the housing, the threaded sleeve is coupled to the valve spool and a first nut is disposed outside the threaded sleeve, a first spring seat is disposed at the end of the valve sleeve, a second spring seat is disposed on the threaded sleeve, a first spring is disposed between an outer wall of the first spring seat and the first nut, and a second spring is disposed between an inner wall of the first spring seat and the second spring seat.

9. The power control valve of claim 8, wherein the threaded sleeve further has an adjustment rod inserted into the end thereof that mates with the valve spool, the adjustment rod being adjusted by a second nut positioned on the adjustment rod.

10. A hydraulic pump comprising a power control valve according to any one of claims 1-9.