阅读说明：本技术 一种功率控制阀块、液压泵组件及工程机械 (Power control valve block, hydraulic pump assembly and engineering machinery ) 是由 李鹏冲 李海军 陈岩 秦慧卿 于 2020-06-29 设计创作，主要内容包括：本发明涉及工程机械技术领域,尤其涉及一种功率控制阀块、液压泵组件及工程机械,功率控制阀块包括溢流阀、凸轮机构、第一梭阀和第二梭阀,凸轮机构包括第一缸体、凸轮以及从动杆,凸轮设置于第一缸体内,凸轮上设置有曲线槽,从动杆的下端位于曲线槽内,从动杆的上端作用于溢流阀的第一压缩弹簧；第一梭阀的两个进油口分别与双向变量泵的两控制油路连通,第一梭阀的出油口与溢流阀的进油口连通；第二梭阀的两个进油口分别与双向变量泵的两工作主油路连通,第二梭阀的出油口与第一缸体的进油口相连通。本发明提供的功率控制阀块可以与不具有功率控制功能的液压泵结合以形成具有功率控制功能的液压泵组件,从而可降低液压系统的成本。(The invention relates to the technical field of engineering machinery, in particular to a power control valve block, a hydraulic pump assembly and engineering machinery, wherein the power control valve block comprises an overflow valve, a cam mechanism, a first shuttle valve and a second shuttle valve, the cam mechanism comprises a first cylinder body, a cam and a driven rod, the cam is arranged in the first cylinder body, a curve groove is formed in the cam, the lower end of the driven rod is positioned in the curve groove, and the upper end of the driven rod acts on a first compression spring of the overflow valve; two oil inlets of the first shuttle valve are respectively communicated with two control oil paths of the bidirectional variable pump, and an oil outlet of the first shuttle valve is communicated with an oil inlet of the overflow valve; two oil inlets of the second shuttle valve are respectively communicated with two working main oil paths of the bidirectional variable pump, and an oil outlet of the second shuttle valve is communicated with an oil inlet of the first cylinder body. The power control valve block provided by the invention can be combined with a hydraulic pump without a power control function to form a hydraulic pump assembly with the power control function, so that the cost of a hydraulic system can be reduced.)

1. A power control valve block, comprising:

an overflow valve (11);

the cam mechanism comprises a first cylinder body (121), a cam (122) and a driven rod (123), wherein the cam (122) is arranged in the first cylinder body (121), a curve groove is formed in the cam (122), the lower end of the driven rod (123) is located in the curve groove, and the upper end of the driven rod (123) acts on a first compression spring of the overflow valve (11);

two oil inlets of the first shuttle valve (13) are respectively communicated with two control oil paths of the bidirectional variable pump, and an oil outlet of the first shuttle valve (13) is communicated with an oil inlet of the overflow valve (11);

two oil inlets of the second shuttle valve (14) are respectively communicated with two working main oil paths of the bidirectional variable pump, and an oil outlet of the second shuttle valve (14) is communicated with an oil inlet of the cam mechanism;

the cam (122) can overcome the set resistance of the cam (122) to move in the first cylinder body (121) under the action of hydraulic oil, and when the cam (122) moves along the oil inlet direction of the first cylinder body (121), the compression amount of the first compression spring is reduced.

2. A power control valve block according to claim 1, wherein the cam mechanism further comprises a second cylinder (124) and a piston (125) and a second compression spring (126) disposed within the second cylinder (124), the piston (125) dividing the second cylinder (124) into a first chamber proximal to the first cylinder (121) and a second chamber distal to the first cylinder (121), the second compression spring (126) disposed in the second chamber, the cam (122) and the piston (125) mechanically coupled by a connecting rod (127), the set resistance of the cam (122) determined by the amount of compression of the second compression spring (126).

3. The power control valve block as recited in claim 2, wherein an adjusting oil port is provided on each of the first and second chambers, and hydraulic oil can adjust a compression amount of the second compression spring (126) through the adjusting oil port.

4. The power control valve block according to claim 1, wherein the cam mechanism further comprises a second compression spring (126), the second compression spring (126) is disposed in the first cylinder (121), one end of the second compression spring (126) abuts against an end surface of the cam (122) away from the oil inlet of the first cylinder (121), the other end of the second compression spring (126) abuts against an inner wall of the first cylinder (121), and the set resistance of the cam (122) is determined by a compression amount of the second compression spring (126).

5. A power control valve block according to claim 1, characterized in that the cam (122) is tapered, the diameter of the cam (122) gradually increases in the direction of the oil intake of the first cylinder (121), and the curved groove opens on the upper surface of the cam (122) along the contour of the cam (122).

6. A hydraulic pump assembly comprising a power control valve block as claimed in any one of claims 1 to 5; further comprising:

the main pump is a bidirectional variable pump (2), and the bidirectional variable pump (2) is connected with a variable control assembly for controlling the swing angle of the bidirectional variable pump, a first control oil path (400) and a second control oil path (500); a first pump working oil port (S) of the main pump is connected with a first working main oil way (100), and a second pump working oil port (P) of the main pump is connected with a second working main oil way (200);

the first control oil path (400) and the second control oil path (500) are respectively connected with two oil inlets of the first shuttle valve (13), and the first work main oil path (100) and the second work main oil path (200) are respectively connected with two oil inlets of the second shuttle valve (14).

7. The hydraulic pump assembly of claim 6, wherein the variable control assembly comprises:

the servo valve (4) is a three-position four-way reversing valve, and the servo valve (4) comprises a first valve working oil port, a second valve working oil port, an oil inlet connected with a pressure oil path (300) of the oil replenishing pump (7) and an oil return port connected with an oil tank;

the chambers on two sides of the piston of the first variable cylinder (3) are respectively connected with the first control oil way (400) and the second control oil way (500), and the piston of the first variable cylinder (3) can move to drive the valve core of the servo valve (4) to move;

and the chambers on two sides of the piston of the second variable cylinder (5) are respectively communicated with the first valve working oil port and the second valve working oil port, and the piston of the second variable cylinder (5) can move to drive the swash plate swing angle of the bidirectional variable pump (2) to change and the valve body of the servo valve (4) to move.

8. The hydraulic pump assembly according to claim 7, characterized in that the oil circuit (300) of the oil replenishment pump (7) is further provided with a filter (10).

9. The hydraulic pump assembly according to claim 6, characterized in that a first overflow valve (110) is connected to the first pump working port (S), and a second overflow valve (120) is connected to the second pump working port (P).

10. A working machine, characterized by comprising a hydraulic pump assembly according to any one of claims 6-9.

Technical Field

The invention relates to the technical field of engineering machinery, in particular to a power control valve block, a hydraulic pump assembly and engineering machinery.

Background

Present closed pump, all do not take power control, can only realize single control, for example: in the modes of manual control, hydraulic pilot control, electric control and the like, when working conditions of large displacement and high pressure are met (for example, when a motor is stuck), the hydraulic pump can instantly reach the angular power value of the hydraulic pump at the instant of the sticking, so that when the power of the selected prime mover is lower than the angular power, the prime mover can be switched off, and in order to prevent the power of the prime mover from being switched off, the prime mover with higher power and capable of covering the angular power point needs to be selected, thereby increasing the cost and wasting the energy consumption.

Disclosure of Invention

The invention aims to provide a power control valve block, a hydraulic pump assembly and engineering machinery, and aims to solve the technical problem that a closed pump in the prior art does not have a power control function.

In order to achieve the purpose, the invention adopts the following technical scheme:

a power control valve block comprising:

an overflow valve;

the cam mechanism comprises a first cylinder body, a cam and a driven rod, the cam is arranged in the first cylinder body, a curve groove is formed in the cam, the lower end of the driven rod is located in the curve groove, and the upper end of the driven rod acts on a first compression spring of the overflow valve;

two oil inlets of the first shuttle valve are respectively communicated with two control oil paths of the bidirectional variable pump, and an oil outlet of the first shuttle valve is communicated with an oil inlet of the overflow valve;

two oil inlets of the second shuttle valve are respectively communicated with two working main oil paths of the bidirectional variable pump, and an oil outlet of the second shuttle valve is communicated with an oil inlet of the cam mechanism;

the cam can overcome the set resistance of cam under the effect of hydraulic oil and move in first cylinder body, and when the cam moves along the oil feed direction of first cylinder body, the decrement of first compression spring diminishes.

As a preferable technical solution of the power control valve block, the cam mechanism further includes a second cylinder, and a piston and a second compression spring that are disposed in the second cylinder, the piston divides the second cylinder into a first chamber close to the first cylinder and a second chamber far from the first cylinder, the second compression spring is disposed in the second chamber, the cam and the piston are mechanically connected by a connecting rod, and the set resistance of the cam is determined by a compression amount of the second compression spring.

As a preferred technical scheme of the power control valve block, the first cavity and the second cavity are both provided with adjusting oil ports, and hydraulic oil can adjust the compression amount of the second compression spring through the adjusting oil ports.

As a preferable technical solution of the power control valve block, the cam mechanism further includes a second compression spring, the second compression spring is disposed in the first cylinder, one end of the second compression spring abuts against an end surface of the cam, which is far away from the oil inlet of the first cylinder, the other end of the second compression spring abuts against an inner wall of the first cylinder, and the set resistance of the cam is determined by a compression amount of the second compression spring.

As a preferred technical scheme of the power control valve block, the cam is conical, the diameter of the cam is gradually increased along the oil inlet direction of the first cylinder body, and the curve groove is formed in the upper surface of the cam along the contour of the cam.

A hydraulic pump assembly comprising a power control valve block as claimed in any one of the preceding claims; further comprising:

the system comprises a main pump, a first oil path and a second oil path, wherein the main pump is a bidirectional variable pump which is connected with a variable control assembly for controlling the swing angle of the bidirectional variable pump, and the first oil path and the second oil path are connected with the bidirectional variable pump; a first pump working oil port of the main pump is connected with a first working main oil way, and a second pump working oil port of the main pump is connected with a second working main oil way;

the first control oil path and the second control oil path are respectively connected with two oil inlets of the first shuttle valve, and the first working main oil path and the second working main oil path are respectively connected with two oil inlets of the second shuttle valve.

As a preferred embodiment of the hydraulic pump assembly, the variable control assembly comprises:

the servo valve is a three-position four-way reversing valve and comprises a first valve working oil port, a second valve working oil port, an oil inlet connected with a pressure oil path of the oil replenishing pump and an oil return port connected with the oil tank;

the chambers on two sides of the piston of the first variable cylinder are respectively connected with the first control oil way and the second control oil way, and the movement of the piston of the first variable cylinder can drive the movement of the valve core of the servo valve;

and chambers on two sides of a piston of the second variable cylinder are respectively communicated with the first valve working oil port and the second valve working oil port, and the movement of the piston of the second variable cylinder can drive the swash plate of the bidirectional variable pump to change the swing angle and the movement of the valve body of the servo valve.

As a preferable technical scheme of the hydraulic pump assembly, the oil pressure path of the oil replenishing pump is also provided with a filter.

As a preferred technical scheme of the hydraulic pump assembly, the first pump working oil port is connected with a first overflow valve, and the second pump working oil port is connected with a second overflow valve.

A working machine comprising a hydraulic pump assembly as claimed in any one of the preceding claims.

The invention has the beneficial effects that:

the power control valve block provided by the invention can be combined with a hydraulic pump without a power control function to form a hydraulic pump assembly with the power control function, so that the cost of a hydraulic system can be reduced, and meanwhile, when the hydraulic pump assembly maintains the constant power module, only the power control valve block is required to be maintained, the whole hydraulic pump does not need to be disassembled for maintenance, and the maintenance cost is reduced.

Drawings

FIG. 1 is a schematic diagram of a hydraulic pump assembly provided by an embodiment of the present invention;

FIG. 2 is a schematic diagram of a power control valve block provided by an embodiment of the present invention;

FIG. 3 is a graph of pressure versus displacement for a main pump provided by an embodiment of the present invention.

In the figure:

1-a power control valve block; 11-an overflow valve; 121-a first cylinder; 122-a cam; 123-driven rod; 124-a second cylinder; 125-a piston; 126-a second compression spring; 127-a connecting rod; 13-a first shuttle valve; 14-a second shuttle valve;

2-a bidirectional variable pump; 3-a first variable cylinder; 4-a servo valve; 5-a second variable cylinder; 6-a feedback rod; 7-oil supply pump; 8-a filter; 9-a first overflow valve; 10-a second overflow valve;

100-a first working main oil way; 200-a second working main oil way; 300-pressing oil way; 400-first control oil circuit; 500-a second control oil circuit;

s-a first pump working oil port; p-a second pump working oil port.

Detailed Description

The technical scheme of the invention is further explained by combining the attached drawings and the embodiment. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some but not all of the elements associated with the present invention are shown in the drawings.

In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, removably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description of the present embodiment, the terms "upper", "lower", "left", "right", and the like are used based on the orientations and positional relationships shown in the drawings only for convenience of description and simplification of operation, and do not indicate or imply that the referred device or element must have a specific orientation, be configured and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used only for descriptive purposes and are not intended to have a special meaning.

As shown in fig. 1, the present invention provides a hydraulic pump assembly for use in a construction machine, which includes a main pump, an oil supply pump 7, and a power control valve block 1, and can implement constant power control of the hydraulic pump assembly. It is to be noted that constant power control is understood that the working power of the hydraulic pump does not exceed a set power value, and is not always operated at a constant power.

Specifically, the main pump is a bidirectional variable displacement pump 2, which includes a first pump working oil port S and a second pump working oil port P, wherein the first pump working oil port S is connected to a first working main oil path 100 in the system, and the second pump working oil port P is connected to a second working main oil path 200. In addition, the bidirectional variable displacement pump 2 is also connected to a variable control unit that can control the swash plate tilt angle thereof, a first control oil passage 400, and a second control oil passage 500.

The variable control assembly comprises a first variable cylinder 3, a second variable cylinder 5 and a servo valve 4, the servo valve 4 can be a three-position four-way reversing valve, and the servo valve 4 comprises a first valve working oil port, a second valve working oil port, an oil inlet connected with a pressure oil path 300 of the oil supplementing pump 7 and an oil return port connected with an oil tank; the chambers on the two sides of the piston of the first variable cylinder 3 are respectively connected with the first control oil path 400 and the second control oil path 500, and the movement of the piston of the first variable cylinder 3 can drive the valve core of the servo valve 4 to move; the chambers on two sides of the piston of the second variable cylinder 5 are respectively communicated with the first valve working oil port and the second valve working oil port, and the piston movement of the second variable cylinder 5 can drive the two-way variable pump 2 to change the swash plate swing angle and the servo valve 4 to move. Specifically, the piston of the first variable cylinder 3 can be connected with the spool of the servo valve 4 through a first connecting rod, the piston of the second variable cylinder 5 can be connected with the swash plate of the bidirectional variable pump 2 through a second connecting rod, the second connecting rod is connected with a feedback rod 6, and the feedback rod 6 is connected with the valve sleeve of the servo valve 4.

During specific work, the pressure acting on two sides of the piston of the first variable cylinder 3 through the first control oil path 400 and the second control oil path 500 pushes the piston to move, so that the valve core of the servo valve 4 is driven to move, and the second variable cylinder 5, the swash plate swing angle of the bidirectional variable pump 2 and the valve sleeve of the servo valve 4 are enabled to move correspondingly.

Supposing that the piston of the first variable cylinder 3 drives the valve core of the servo valve 4 to move leftwards under the action of the pressure difference between the first control oil path 400 and the second control oil path 500, oil from the oil pressing path 300 of the oil replenishing pump 7 enters the right cavity of the second variable cylinder 5 through the servo valve 4, the oil entering the second variable cylinder 5 pushes the piston of the second variable cylinder 5 to move leftwards, and the position of the swash plate of the bidirectional variable pump 2 is changed so as to change the displacement of the bidirectional variable pump 2. And the piston of the second variable cylinder 5 acts and simultaneously drives the valve sleeve of the servo valve 4 connected with the feedback rod 6 to move leftwards, and the servo valve 4 is closed, so that the discharge capacity of the bidirectional variable pump 2 is stable. In this embodiment, the servo valve 4 selects a direction change valve whose neutral position function is H-type, so that the servo valve 4 is in a closed state when the direction change valve is in the neutral position.

Specifically, referring to fig. 1 and 2, the power control valve block 1 includes an overflow valve 11, a cam mechanism, a first shuttle valve 13, and a second shuttle valve 14, wherein: the cam mechanism comprises a first cylinder body 121, a cam 122 and a driven rod 123, the cam 122 is arranged in the first cylinder body 121, a curved groove is formed in the cam 122, the lower end of the driven rod 123 is located in the curved groove, and the upper end of the driven rod 123 acts on a first compression spring of the overflow valve 11; two oil inlets of the first shuttle valve 13 are respectively communicated with two control oil paths of the bidirectional variable pump 2, namely two oil inlets of the first shuttle valve 1311 are respectively communicated with the first control oil path 400 and the second control oil path 500, an oil outlet of the first shuttle valve 13 is communicated with an oil inlet of the overflow valve 11, and an oil outlet of the overflow valve 11 is communicated with an oil tank; two oil inlets of the second shuttle valve 14 are respectively communicated with two working main oil passages of the bidirectional variable displacement pump 2, that is, two oil inlets of the second shuttle valve 14 are respectively communicated with the first working main oil passage 100 and the second working main oil passage 200, an oil outlet of the second shuttle valve 14 is communicated with an oil inlet of the first cylinder 121, the cam 122 can overcome the set resistance of the cam 122 to move in the first cylinder 121 under the action of hydraulic oil, and when the cam 122 moves along the oil inlet direction of the first cylinder 121, the compression amount of the first compression spring becomes small. It can be understood that the opening pressure of the relief valve 11 is determined by the compression amount of the compression spring, and the larger the compression amount of the compression spring is, the larger the opening pressure of the relief valve 11 is, whereas the smaller the compression amount of the compression spring is, the smaller the opening pressure of the relief valve 11 is.

When the main pump in the hydraulic pump assembly is in a normal working state, the pressure of the first working main oil path 100 connected with the first pump working oil port S or the pressure of the second working oil path connected with the second pump working oil port P is increased and exceeds a set power value, so that the power of the main pump is in an increasing trend. Since the power of the main pump is equal to the product of the working pressure and the flow of the main pump, the flow depends on the discharge capacity of the main pump and the rotating speed of the engine driving the main pump, and the rotating speed of the engine is usually set to be basically constant, the discharge capacity of the main pump needs to be reduced so that the power of the main pump does not exceed the set maximum power. In this embodiment, when the pressure of the first work master oil path 100 or the pressure of the second work master oil path 200 increases, the pressure oil is introduced into the first cylinder 121 of the cam mechanism to push the cam 122 to move along the oil inlet direction of the first cylinder 121, the cam 122 acts on the first compression spring of the relief valve 11 through the driven rod 123, and the compression amount of the first compression spring decreases, so that the opening pressure of the relief valve 11 decreases, and further the pressure value of the first control oil path 400 or the second control oil path 500 can be reduced, that is, the control oil pressure of the master pump is reduced, so that the displacement of the master pump is reduced, and the power of the master pump does not exceed the set value.

Through setting up power control valve block 1, make it can combine in order to form the hydraulic pump subassembly that has power control function with the hydraulic pump that does not have power control function to can reduce hydraulic system's cost, when hydraulic pump subassembly was maintained the constant power module simultaneously, only need maintain power control valve block 1, need not to unpack whole hydraulic pump apart to overhaul the maintenance, reduced the maintenance cost.

Further, the cam mechanism further includes a second cylinder 124, and a piston 125 and a second compression spring 126 which are disposed in the second cylinder 124, the piston 125 divides the second cylinder 124 into a first cavity close to the first cylinder 121 and a second cavity far from the first cylinder 121, the second compression spring 126 is disposed in the second cavity, the cam 122 and the piston 125 are mechanically connected by a connecting rod 127, and the set resistance of the cam 122 is determined by the compression amount of the second compression spring 126. Alternatively, in another embodiment, the second cylinder 124 and the piston 125 may not be provided, but the second compression spring 126 may be provided in the first cylinder 121, one end of the second compression spring 126 abuts against an end surface of the cam 122 away from the oil inlet of the first cylinder 121, the other end of the second compression spring 126 abuts against an inner wall of the first cylinder 121, and the set resistance of the cam 122 is determined by the compression amount of the second compression spring 126.

The system pressure depends on the pressure of the first pump working oil port S or the second pump working oil port P, and the compression amount of the second compression spring is a fixed value, so that when the system pressure is increased, the control oil pressure of the main pump is reduced, and the displacement of the main pump is reduced; when the system pressure decreases, the control oil pressure of the main pump increases, and the displacement of the main pump increases. From this, a relationship P × V ═ kx is obtained, P is the high-pressure of the pump working port P/S, V is the main pump displacement, k is the stiffness coefficient of the second compression spring 126, and x is the compression amount of the second compression spring 126. Since the second compression spring 126 is rigid and has a small compression amount, kx is approximately assumed to be constant, so that the pressure-displacement relationship curve of the main pump is a hyperbolic curve (e.g., curve a in fig. 3). Because T is pV/20 pi, wherein T is torque, P is high-pressure of a pump working oil port P/S, and V is main pump displacement, the product of P and V is a constant value, and constant torque control can be realized. And because P is 2 pi Tn/60000, wherein P is the power of the pump, T is the torque of the pump, and n is the rotation speed of the pump, when the rotation speed of the pump is not changed, the constant power control can be realized.

Further, all be provided with on first chamber and the second chamber and adjust the hydraulic fluid port, hydraulic oil can be through adjusting the compressive capacity of oil port regulation second compression spring 126 to realize that the relation curve of main pump's pressure and discharge capacity upwards or squints downwards (like curve B and curve C in fig. 3), thereby change pump power size.

Furthermore, because the curved groove on the surface of the cam 122 can be processed with different slopes, different slopes of the hyperbola can be realized, and the curve of the engine can be better met.

In addition, the hydraulic pump assembly is mostly used in a closed circuit, and a filter 8 may be disposed on the pressure oil path 300 of the oil replenishing pump 7 in order to ensure the cleanliness of oil in the closed circuit.

In addition, it can be understood that the first pump working port S is also connected with a first relief valve 9, and the second pump working port P is connected with a second relief valve 10 to limit the pressure of the bidirectional variable displacement pump 2 during operation.

The embodiment also provides the engineering machinery, and the traveling system of the engineering machinery can be provided with the hydraulic pump assembly so as to realize constant power control.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.