CN115750321A - Integrated oil-supplementing one-way overflow valve for closed hydraulic plunger variable pump - Google Patents

Abstract

The invention discloses an integrated oil-supplementing one-way overflow valve for a closed hydraulic plunger variable pump, which comprises a valve sleeve, wherein a large valve core is arranged in the valve sleeve, a small valve core is arranged in the large valve core, a first spring is arranged on the large valve core, and a second spring is arranged on the small valve core; one end of the valve sleeve is provided with a first inlet and a first outlet, and the side wall of the valve sleeve is provided with a second inlet and a second outlet; a first through fracture is formed between the large valve core and the valve sleeve; a second break-through port is formed between the large valve core and the small valve core, one side of the second break-through port is communicated with the first inlet and the second outlet, and the other side of the second break-through port is communicated with the second inlet and the second outlet; the oil-gas separator also comprises a control oil passage with at least three ports. The invention has two functions of integrating the one-way oil supplementing valve and the high-pressure overflow valve, is suitable for two oil ways of a pilot type and a direct-acting type, improves the compatibility of the end cover, and reduces the manufacturing cost of the end cover of the closed hydraulic plunger variable pump.

Description

Integrated charge one-way relief valve for closed hydraulic plunger variable pump

technical field

The invention belongs to the field of closed hydraulic plunger variable pumps, in particular to an integrated oil-supplement one-way overflow valve for closed hydraulic plunger variable pumps.

Background technique

Closed hydraulic plunger variable pumps are widely used in construction machinery such as truck cranes, crawler cranes, road rollers, and aerial work platforms. Compared with the open hydraulic system, the pipeline connection of the system becomes simpler, which not only greatly saves the installation space, but also reduces the leakage and pipeline vibration caused by the pipeline connection, and improves the reliability of the system. The closed hydraulic system can reduce the chance of air entering the oil, which can make the whole hydraulic system run more smoothly. At the same time, the closed hydraulic piston variable pump can directly control the flow direction of the output oil, and the transition is smooth, avoiding various problems in the hydraulic system. The hydraulic shock generated by the valve. Therefore, the closed hydraulic piston variable pump is favored by more and more hosts.

The closed hydraulic system has continuous oil loss during work (oil loss caused by the volumetric efficiency of the closed hydraulic piston variable pump, leakage of the actuator, leakage of the pipeline, leakage of the valve in the closed hydraulic system, etc.), In order to make up for the oil loss of the closed hydraulic system and ensure the normal operation of the entire closed hydraulic system, a small displacement quantitative pump is usually integrated on the closed hydraulic piston variable pump, which is called a charge pump. The displacement of the charge oil pump is small and the pressure is low, and the outlet pressure of the charge oil pump is limited by the built-in charge oil relief valve. The closed hydraulic plunger variable pump has two independent outlets, A/B, which can be used as high-pressure oil ports or low-pressure oil ports. A/B ports are isolated by two check valves, and A/B ports are separated by two high-pressure relief ports The flow valve is connected, and the charge pump replenishes the oil lost in the closed hydraulic system to the low-pressure side of the A/B port through the check valve, and the charge pump always communicates with the low-pressure side of the A/B port. Two high-pressure relief valves at port A/B limit the maximum pressure of their respective oil ports to prevent overloading of the closed hydraulic system. When the pressure of the closed hydraulic system is lower than the opening pressure set by the two high-pressure relief valves, A/B When the pressure of the closed hydraulic system is higher than the opening pressure set by the two high-pressure relief valves, the high-pressure relief valve on the high-pressure side of the A/B port opens to communicate with the A/B port.

High-pressure relief valves are divided into pilot-operated relief valves and direct-acting relief valves. The basic principle of the high-pressure relief valve is to adjust the pressure through the negative feedback effect formed by the balance and movement of the spool.

The working principle of the pilot-operated relief valve is: when the pressure oil flows in from the inlet, the pressure acts on the lower end surface of the main valve core. The inside of the valve body is designed with a damping hole, and the pressure oil enters the right chamber of the pilot valve after passing through the damping hole. And finally act on the spool of the pilot relief valve. The spool of the pilot relief valve is normally closed due to the force of the spring, and the preset pressure of the spring can be adjusted through the external adjustment handle. When the hydraulic pressure is lower than the pre-adjusted pressure of the spring, the pilot spool is always in a closed state, and the main spool has no corresponding action at this time. When the system pressure rises, the internal hydraulic pressure of the pilot valve is greater than the pre-adjusted pressure of the spring, and the pilot valve is opened. Under the depressurization effect of the damping hole, a pressure difference is generated between the upper and lower sides of the main valve core, so the main valve core is lifted up, and the original sealing The oil inlet and outlet are connected, and the pressure oil is directly from the oil inlet to the oil outlet to realize unloading.

The working principle of the direct-acting relief valve is: when the direct-acting relief valve is connected to the system, the hydraulic oil acts on the valve core to generate force, and the direction of the force is opposite to the direction of the pre-adjusted pressure of the spring. When the port pressure is lower than the set pressure of the relief valve, the spool does not open, and the pressure at the oil inlet mainly depends on the external load. When the force of the oil is greater than the spring preset pressure, the valve core opens, and the oil flows back to the oil tank from the overflow port. The spring force increases with the increase of the opening of the relief valve until it is balanced with the hydraulic force. When the relief valve begins to overflow, the pressure at the oil inlet is basically stable at the set value, which acts as a relief valve. The role of flow stabilization. The pressure adjusting screw adjusts the pre-compression of the spring to adjust the overflow pressure value of the overflow valve.

The one-way valve achieves the purpose of automatic opening and closing through the flow of oil itself, so as to prevent the situation of oil backflow. Under normal circumstances, the installation method of the check valve is to enter from the top and to exit from the bottom. Installing a check valve at the outlet of the closed pump can avoid damage to the closed pump and the system due to oil loss in the closed system, thus playing a role in system protection.

According to the working principle of the closed plunger variable displacement pump, the closed plunger variable displacement pump usually does not have the function of the charge relief valve, so it is necessary to integrate the charge check valve and the high pressure relief valve. Because the direct-acting relief valve and the pilot-operated relief valve have different oil inlet methods, it is usually necessary to design different cross oil passages on the end cover (A/B ports are on the end cover) of the closed plunger variable displacement pump. For relief valves with different oil inlet methods, it is also necessary to design an oil circuit on the end cover to cooperate with the oil supply check valve, resulting in various states of the end cover and increasing the manufacturing cost.

Therefore, there is an urgent need for a new control valve, which not only has the functions of oil-charging check valve and high-pressure relief valve, but also can be applied to a variety of oil circuits, and can be matched with different oil inlet methods to reduce the oil crossing of the back cover. road, improve the versatility of the back cover, and also reduce the manufacturing cost of the end cover of the closed plunger variable pump.

Contents of the invention

The object of the present invention is to provide an integrated oil-charging one-way overflow valve for a closed hydraulic plunger variable pump. The invention has two functions of integrated one-way oil supply valve and high-pressure relief valve, is suitable for two kinds of oil circuits of pilot type and direct-acting type, improves the compatibility of the end cover, and reduces the manufacturing of the end cover of the closed hydraulic plunger variable pump. cost advantage.

The technical scheme of the present invention: the integrated oil-replenishing one-way overflow valve for the closed hydraulic plunger variable pump includes a valve sleeve, a large valve core is arranged in the valve sleeve, a small valve core is arranged in the large valve core, and a large valve core is arranged in the valve sleeve. There is a first spring connected to the valve sleeve on the top, and a second spring connected to the large valve core on the small valve core;

One end of the valve sleeve is provided with a first inlet and outlet, and the side wall of the valve sleeve is provided with a second inlet and outlet; a first opening is formed between the large valve core and the valve sleeve, and the first opening is located between the first inlet and outlet and the second opening. Between the inlet and outlet; a second opening is formed between the large spool and the small spool, one side of the second opening is connected to the first inlet and outlet, and the other side of the second opening is connected to the second inlet and outlet;

It also includes a control oil passage with at least three ports, one end of the control oil passage is connected to the first inlet and outlet, the other end of the control oil passage is connected to the inner end surface of the large spool, and the remaining end of the control oil passage is connected to the outer end surface of the small spool .

In the aforementioned integrated oil-replenishing one-way relief valve for closed-type hydraulic plunger variable pumps, the inner side end of the large spool is in sliding connection with the valve sleeve, and the outer peripheral surface of the large spool is provided with a first stepped surface and a second Step surface, the first step surface is located at the first entrance and exit, the second step surface is located at the second entrance and exit, the second step surface is connected to the first step surface through the first taper surface, and the first opening is formed on the first taper surface between the valve sleeve.

In the aforementioned integrated oil-charging one-way relief valve for the closed hydraulic plunger variable pump, a third through hole is provided at the junction of the first conical surface or the first conical surface and the first stepped surface, and the third through hole is The hole is an integral part of the control oil passage.

In the aforementioned integrated oil-charging one-way relief valve for closed hydraulic piston variable pumps, the first spring is located between the valve sleeve and the large valve core, and one end of the first spring is connected to the large valve core through a retaining ring. The other end of a spring is connected with the first screw plug, and the first screw plug is connected with the end of the valve sleeve.

In the aforementioned integrated oil-replenishing one-way relief valve for closed-type hydraulic plunger variable pumps, the small valve core is provided with a cone, and the cone is provided with a second cone surface, and the second on-off opening is formed with the second Between the cone surface and the large spool.

In the aforementioned integrated oil-charging one-way relief valve for a closed-type hydraulic plunger variable pump, the large valve core is provided with a first through hole communicating with the second inlet and outlet.

In the aforementioned integrated oil-replenishing one-way relief valve for closed-type hydraulic plunger variable pumps, the inner end of the small valve core is provided with a first spring seat, and the small valve core is connected to the conical surface of the first spring seat. The spring seat is connected to the second spring seat through the second spring, and the second spring seat is connected to the large valve core through the limit pin.

In the aforementioned integrated oil-charging one-way relief valve for a closed-type hydraulic plunger variable pump, the end of the large valve core close to the first inlet and outlet is provided with a second screw plug.

In the aforementioned integrated oil-charging one-way relief valve for a closed hydraulic plunger variable pump, the end of the small valve core close to the second screw plug extends radially outward to form a piston body, and the piston body and the large valve core Clearance fit, an oil chamber is formed between the piston body and the second screw plug, an annular groove is provided on the outer peripheral surface of the small valve core, the annular groove is located between the cone and the piston body, and a second ring groove is provided on the bottom surface of the annular groove The through hole and the second through hole communicate with the end face of the small valve core close to the first spring seat; the oil chamber, the gap between the piston body and the large valve core, the annular groove and the second through hole are all components of the control oil passage.

In the aforementioned integrated oil-charging one-way relief valve for the closed hydraulic plunger variable pump, the first spring seat and the second spring seat are both provided with a fourth through hole in the axial direction, and the fourth through hole is a control valve. Components of the oil passage.

Compared with the prior art, the present invention has two functions of one-way oil replenishment and high-pressure relief, which is equivalent to integrating the existing oil-charge one-way valve and high-pressure relief valve together, connected to the closed hydraulic plunger variable It is used on the A/B port of the pump, and it is suitable for both the pilot relief valve and the direct-acting relief valve circuit, so it is not necessary to design a complicated oil circuit on the end cover of the closed plunger variable displacement pump, and the end cover can be simplified. cover manufacturing costs.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

Fig. 2 is the hydraulic principle diagram used on the closed hydraulic plunger variable pump of the present invention.

The marks in the accompanying drawings are: 1-valve sleeve, 2-big spool, 3-small spool, 4-first spring, 5-second spring, 6-first opening, 7-second opening, 9-first spring seat, 10-second spring seat, 11-limit pin, 12-oil chamber, 13-fourth through hole;

100-the first import and export, 101-the second import and export;

200-first step surface, 201-second step surface, 202-first cone surface, 203-third through hole, 204-retaining ring, 205-first screw plug, 206-second screw plug;

300-cone, 301-second cone, 303-first through hole, 304-piston body, 305-annular groove, 306-second through hole;

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments, but not as a basis for limiting the present invention.

Example. The integrated oil-supplement one-way relief valve for the closed hydraulic plunger variable pump, as shown in Figure 1, includes the valve sleeve 1, the valve sleeve 1 is equipped with a large valve core 2, and the large valve core 2 is equipped with a small valve core 3. The large spool 2 is provided with a first spring 4 connected with the valve sleeve 1, and the small spool 3 is provided with a second spring 5 connected with the large spool 2.

One end of the valve sleeve 1 is provided with a first inlet and outlet 100, and the side wall of the valve sleeve 1 is provided with a second inlet and outlet 101; a first opening 6 is formed between the large valve core 2 and the valve sleeve 1, and the first opening 6 Located between the first inlet and outlet 100 and the second inlet and outlet 101; the second opening 7 is formed between the large spool 2 and the small spool 3, and one side of the second opening 7 is connected to the first inlet and outlet 100, the second The other side of the on-off port 7 is connected to the second inlet and outlet 101; with the first on-off port 6 as the boundary line, the axial oil pressure area of the large valve core 2 near the first inlet and outlet 100 is greater than the oil pressure on the inner side of the large spool 2 area.

It also includes a control oil passage with three ports, one end of the control oil passage is connected to the first inlet and outlet 100, the other end of the control oil passage is connected to the inner end surface of the large spool 2, and the remaining end of the control oil passage is connected to the small spool 3. Outer end face.

The inner end of the large valve core 2 is slidingly connected with the valve sleeve 1, and the outer peripheral surface of the large valve core 2 is provided with a first stepped surface 200 and a second stepped surface 201, the first stepped surface 200 is located at the first inlet and outlet 100, The second stepped surface 201 is located at the second inlet and outlet 101 , the second stepped surface 201 is connected to the first stepped surface 200 through the first tapered surface 202 , and the first opening 6 is formed between the first tapered surface 202 and the valve sleeve 1 .

The first tapered surface 202 or the junction of the first tapered surface 202 and the first stepped surface 200 is provided with a third through hole 203, and the third through hole 203 is a component of the control oil passage.

The first spring 4 is located between the valve sleeve 1 and the large spool 2, one end of the first spring 4 is connected to the large spool 2 through a retaining ring 204, the other end of the first spring 4 is connected to the first screw plug 205, the first The screw plug 205 is connected to the end of the valve sleeve 1 .

The small valve core 3 is provided with a cone 300 , the cone 300 is provided with a second cone surface 301 , and the second opening 7 is formed between the second cone surface 301 and the large valve core 2 .

The large valve core 2 is provided with a first through hole 303 communicating with the second inlet and outlet 101 , and the first through hole 303 is located on one side of the cone 300 .

The inner end of described small spool 3 is provided with first spring seat 9, and small spool 3 is connected with first spring seat 9 conical surfaces, and first spring seat 9 connects second spring seat 10 by second spring 5, and second The spring seat 10 is connected to the large valve core 2 through a limit pin 11 .

A second screw plug 206 is provided at the end of the large valve core 2 near the first inlet and outlet 100 .

The end of the small spool 3 close to the second screw plug 206 extends radially outward to form a piston body 304, the piston body 304 is in clearance fit with the large spool 2, and oil is formed between the piston body 304 and the second screw plug 206. Cavity 12, the outer peripheral surface of the small valve core 3 is provided with an annular groove 305, the annular groove 305 is located between the cone 300 and the piston body 304 and communicates with the third through hole 203, the bottom surface of the annular groove 305 is provided with a second Through hole 306, the second through hole 306 communicates with the end face of the small valve core 3 near the first spring seat 9; the gap between the oil chamber 12, the piston body 304 and the large valve core 2, the annular groove 305 and the second through hole 306 are all It is an integral part of the control oil passage.

Both the first spring seat 9 and the second spring seat 10 are provided with a fourth through hole 13 in the axial direction, and the fourth through hole 13 is an integral part of the control oil passage.

Use of the present invention: as shown in Figure 2, two supplementary one-way overflow valves are used on a closed hydraulic plunger variable pump, and one of the supplementary one-way overflow valves is recorded as valve M, and the other supplementary The oil one-way relief valve is denoted as valve N, valve M and valve N are respectively connected to the A/B port of the closed hydraulic plunger variable pump, so that A port is connected to the first inlet and outlet 100 of valve N, and B port is connected to valve M the first inlet and outlet 100 of the valve N, and then connect the second inlet and outlet 101 of the valve N to the second inlet and outlet 101 of the valve M. When side A is high pressure and side B is low pressure, valve M acts as a charge check valve, valve N acts as a high pressure relief valve, and valve N check valve is closed. When the pressure on side A reaches the preset value set by valve N When the pressure is high, the valve N opens to communicate with the A/B side oil circuit, and the inlet oil is directly passed to the outlet to realize the high pressure unloading function.

Specific working principle: when the first inlet and outlet 100 are under high pressure, the high-pressure oil enters the annular groove 305 through the third through hole 203, and a part of the high-pressure oil enters the oil chamber 12 through the gap between the piston body 304 and the large valve core 2, communicate with the upper end surface of the lower spool, and another part of the high-pressure oil enters the inner cavity of the valve sleeve 1 through the second through hole 306 and the fourth through hole 13, and communicates with the lower end surface of the large spool 2, because the upper end of the large spool 2 The oil pressure area is smaller than the oil pressure area at the lower end, the large spool 2 is always in the closed state, the first open port 6 remains in the disconnected state, and the large spool 2 will not be opened. When the high pressure oil pressure continues to rise, since the lower end of the small spool 3 has a conical surface, the oil pressure area of the upper end of the small spool 3 is larger than the oil pressure area of the lower end, and the small spool 3 overcomes the elastic force of the second spring 5 and moves downward , the second opening 7 is opened, and the high-pressure oil at port A enters port B through the third through hole 203, the annular groove 305, the first through hole 303, and the second inlet and outlet 101, and the port A communicates with port B to realize high-pressure overflow unloading.

When the first inlet and outlet 100 are at low pressure, the supplementary pressure oil enters the second inlet and outlet 101 from port B, and the supplementary pressure oil applies downward pressure to the large valve core 2 through the end face of the second stepped surface 201. When the supplementary oil When the pressure reaches the preset pressure, the large spool 2 overcomes the elastic force of the first spring 4 and moves downward, the first port 6 is opened, the first inlet and outlet 100 communicate with the second inlet and outlet 101, and the pressure oil from port B enters into the A port, to achieve oil replenishment. For the small spool 3, since the oil pressure area on the upper side of the cone 300 is smaller than the oil pressure area on the lower side, the oil supply pressure on the cone 300 is upward, so that the second opening 7 is always kept in an open state, and the small spool 3 will not open .

Claims (10)

1. The integrated oil-supplementing one-way overflow valve for the closed hydraulic plunger variable pump is characterized in that: the valve comprises a valve sleeve (1), wherein a large valve core (2) is arranged in the valve sleeve (1), a small valve core (3) is arranged in the large valve core (2), a first spring (4) connected with the valve sleeve (1) is arranged on the large valve core (2), and a second spring (5) connected with the large valve core (2) is arranged on the small valve core (3);

one end of the valve sleeve (1) is provided with a first inlet and outlet (100), and the side wall of the valve sleeve (1) is provided with a second inlet and outlet (101); a first through-cut opening (6) is formed between the large valve core (2) and the valve sleeve (1), and the first through-cut opening (6) is positioned between the first inlet and outlet (100) and the second inlet and outlet (101); a second communication port (7) is formed between the large valve core (2) and the small valve core (3), one side of the second communication port (7) is communicated with the first inlet and outlet (100), and the other side of the second communication port (7) is communicated with the second inlet and outlet (101);

the oil-gas separator further comprises a control oil duct with at least three ports, one end of the control oil duct is communicated with the first inlet and outlet (100), the other end of the control oil duct is communicated with the end face of the inner side of the large valve core (2), and the rest end of the control oil duct is communicated with the end face of the outer side of the small valve core (3).

2. The integrated oil-replenishing one-way overflow valve for the closed hydraulic plunger variable pump according to claim 1, characterized in that: the inner side end of the large valve core (2) is connected with the valve sleeve (1) in a sliding mode, a first step surface (200) and a second step surface (201) are arranged on the outer peripheral surface of the large valve core (2), the first step surface (200) is located at the first inlet and outlet (100), the second step surface (201) is located at the second inlet and outlet (101), the second step surface (201) is connected with the first step surface (200) through a first conical surface (202), and a first fracture (6) is formed between the first conical surface (202) and the valve sleeve (1).

3. The integrated oil-replenishing one-way overflow valve for the closed hydraulic plunger variable pump according to claim 2, characterized in that: and a third through hole (203) is formed at the joint of the first conical surface (202) or the first conical surface (202) and the first stepped surface (200), and the third through hole (203) is a component of the control oil passage.

4. The integrated oil-replenishing one-way overflow valve for the closed hydraulic plunger variable pump according to claim 2, characterized in that: the first spring (4) is located between the valve sleeve (1) and the large valve core (2), one end of the first spring (4) is connected with the large valve core (2) through a check ring (204), the other end of the first spring (4) is connected with a first plug (205), and the first plug (205) is connected to the end portion of the valve sleeve (1).

5. The integrated oil-replenishing one-way overflow valve for the closed hydraulic plunger variable pump according to claim 1, characterized in that: a cone (300) is arranged on the small valve core (3), a second conical surface (301) is arranged on the cone (300), and the second through-hole (7) is formed between the second conical surface (301) and the large valve core (2).

6. The integrated oil-replenishing one-way overflow valve for the closed hydraulic plunger variable pump according to claim 5, characterized in that: and a first through hole (303) communicated with the second inlet and outlet (101) is formed in the big valve core (2).

7. The integrated oil-replenishing one-way overflow valve for the closed hydraulic plunger variable pump according to claim 5, characterized in that: the inner side end of the small valve core (3) is provided with a first spring seat (9), the small valve core (3) is connected with the conical surface of the first spring seat (9), the first spring seat (9) is connected with a second spring seat (10) through a second spring (5), and the second spring seat (10) is connected with the large valve core (2) through a limiting pin (11).

8. The integrated oil-supplementing one-way overflow valve for the closed hydraulic plunger variable pump according to claim 7, characterized in that: and a second plug (206) is arranged at the end part of the big valve core (2) close to the first inlet and outlet (100).

9. The integrated oil-supplementing one-way overflow valve for the closed hydraulic plunger variable pump according to claim 8, characterized in that: the end part of the small valve core (3) close to the second plug (206) extends outwards in the radial direction to form a piston body (304), the piston body (304) is in clearance fit with the large valve core (2), an oil cavity (12) is formed between the piston body (304) and the second plug (206), an annular groove (305) is formed in the outer peripheral surface of the small valve core (3), the annular groove (305) is located between the cone (300) and the piston body (304), a second through hole (306) is formed in the bottom surface of the annular groove (305), and the second through hole (306) is communicated with the end face, close to the first spring seat (9), of the small valve core (3); the oil cavity (12), the clearance between the piston body (304) and the large valve core (2), the annular groove (305) and the second through hole (306) are all components of a control oil passage.

10. The integrated oil-supplementing one-way overflow valve for the closed hydraulic plunger variable pump according to claim 7, characterized in that: the first spring seat (9) and the second spring seat (10) are both provided with a fourth through hole (13) in the axial direction, and the fourth through hole (13) is a component of the control oil passage.

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