Hydraulic control reversing valve and brake circulation system for loader

Abstract

The utility model discloses a hydraulic control reversing valve and a brake circulation system for a loader, and belongs to the technical field of engineering machinery. The defects that in the prior art, a traditional brake system is poor in brake effect and even fails due to the fact that brake fluid in a pipeline is lacked are overcome. A main body structure of the hydraulic control system comprises an air storage tank, an air brake valve, a booster pump, a brake caliper, a hydraulic control reversing valve and an oil tank, the air brake valve is respectively connected with air inlets of the air storage tank and the booster pump, a port P of the hydraulic control reversing valve is connected with a high-pressure oil port of the booster pump, a port A is connected with an oil inlet of the brake caliper, a port B is connected with an oil outlet of the brake caliper, and a port T is connected with the oil tank. The utility model is mainly applied to engineering machinery such as loaders and the like.

Description

Technical Field

[0001] The utility model belongs to the technical field of engineering machinery, and in particular relates to a hydraulically controlled reversing valve and a brake circulation system for a loader thereof. Background Art

[0002] Among the existing loader braking systems, air-over-oil dry-axle brakes have the lowest cost and are the most widely used, but their reliability is currently unstable. This is because when braking, a large amount of heat is generated when the brake caliper and the brake disc rub against each other, causing the brake oil to boil or even vaporize. When the pedal is released, the brake fluid spurts out from the vent of the booster pump oil cup, and the brake fluid in the pipeline is lacking, resulting in poor braking effect or even failure, which is extremely dangerous.

[0003] Therefore, in the prior art, a forward check valve is added behind the booster pump, and a pneumatic or electrically controlled reversing valve is installed behind the brake caliper. When the pedal is pressed on the pedal valve, the reversing valve is closed to brake; when the pedal is released, the reversing valve discharges high-pressure and high-temperature oil once to complete a cycle. Therefore, the use of pneumatically controlled reversing valves has problems such as inaccurate air pressure control and poor brake follow-up when the brake is released. When an electrically controlled reversing valve is used, the control is complex and requires the pressure of the air pressure sensor to be converted into current and then reversely controlled to control the on-off of the proportional valve. Especially for coal safety conditions, the solenoid valve and sensor must also meet coal safety certification requirements, which is more expensive and has a higher failure rate. Utility Model Content

[0004] The technical problem to be solved by the utility model is to overcome the deficiencies of the prior art and provide a hydraulically controlled reversing valve and a brake circulation system for a loader thereof.

[0005] In order to achieve the above purpose, the utility model is implemented by adopting the following technical solutions:

[0006] A hydraulically controlled reversing valve comprises a reversing valve body, on which joint 1, a one-way valve joint body, joint 2 and joint 3 are installed, a valve core and spring 2 installed on the valve core are arranged in the reversing valve body, and spring 1 and a one-way valve core are arranged in the one-way valve joint body.

[0007] Preferably, the connector 2 is provided with a P port, and the one-way valve connector body is provided with an A port. When the pressure at the P port is greater than x bar, the P port is connected to the A port.

[0008] Preferably, the connector 1 is provided with a T port, and the connector 3 is provided with a B port. When the spring force of the spring 2 plus the pressure of the B port is greater than the pressure of the P port, the B port is connected with the T port.

[0009] Preferably, a gap seal is formed between the reversing valve body and the valve core.

[0010] Preferably, the reversing valve body and the valve core are sealed by an O-ring.

[0011] A brake circulation system for a loader comprises an air storage tank, an air brake valve, a booster pump, a brake caliper and an oil tank, wherein the air brake valve is connected to the air storage tank and the booster pump respectively, and the brake circulation system for the loader further comprises the hydraulically controlled reversing valve as described above, wherein the P port of the hydraulically controlled reversing valve is connected to the high-pressure oil port of the booster pump, the A port is connected to the oil inlet of the brake caliper, the B port is connected to the oil outlet of the brake caliper, and the T port is connected to the oil tank.

[0012] Preferably, a filter is provided between the T-port of the hydraulically controlled reversing valve and the oil tank.

[0013] Preferably, a filter element is provided between the P port of the hydraulically controlled reversing valve and the high-pressure oil port of the booster pump.

[0014] Compared with the prior art, the beneficial effects of the utility model are:

[0015] 1. It is applied to the brake circulation system through the hydraulically controlled reversing valve. When the pedal is stepped on, the oil of the brake caliper is disconnected from the return oil circuit. When the pedal is released, the brake caliper oil proportionally reduces the pressure to release the brake pressure. Through the hydraulically controlled reversing valve, the system is simple, the control is reliable, and the cost is low;

[0016] 2. The hydraulically controlled reversing valve in the utility model can be used for both the air brake system and the circulation of the full hydraulic brake system;

[0017] 3. The brake system adopts a hydraulically controlled reversing valve, which has good brake release followability and circulates and cools the brake fluid, effectively reducing the brake fluid temperature and improving the safety performance of braking. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a structural schematic diagram of the hydraulically controlled reversing valve in the utility model;

[0019] Figure 2 It is a hydraulic principle diagram of the brake circulation system for the loader in the utility model;

[0020] Figure 3 This is a schematic diagram of the structure of Example 3 of the present utility model;

[0021] Figure 4 It is a schematic diagram of the followability of the pressures at the P and B ports when the pedal is released in the utility model.

[0022] In the figure: 1. Air storage tank; 2. Air brake valve; 3. Booster pump; 4. Hydraulic control reversing valve; 5. Brake caliper; 6. Oil tank; 7. Filter; 8. Connector 1; 9. Reversing valve body; 10. One-way valve connector body; 11. Spring 1; 12. One-way valve core; 13. Connector 2; 14. Valve core; 15. Spring 2; 16. O-ring; 17. Connector 3. DETAILED DESCRIPTION

[0023] The present invention will be further described below through specific embodiments in conjunction with the accompanying drawings.

[0024] Embodiment 1:

[0025] like Figure 1 As shown, a hydraulically controlled reversing valve comprises a reversing valve body 9, on which a connector 1 8, a one-way valve connector body 10, a connector 2 13 and a connector 3 17 are installed, a valve core 14 and a spring 2 15 installed on the valve core 14 are arranged in the reversing valve body 9, and a spring 1 11 and a one-way valve core 12 are arranged in the one-way valve connector body 10.

[0026] The connector 2 13 is provided with a P port, and the one-way valve connector body 10 is provided with an A port. When the pressure at the P port is greater than x bar, the P port is connected to the A port.

[0027] In this embodiment, the hydraulically controlled reversing valve 4 can realize that when the pedal is released, when the pressure of the P port decreases, the pressure of the B port also decreases proportionally, and at the same time, the oil in the A port and the B port will not return to the P port, so the brake followability of the hydraulically controlled reversing valve is good. Figure 4 shown.

[0028] The opening pressure of the one-way valve composed of the spring 11 and the one-way valve core 12 in the hydraulic control reversing valve 4 is 6 bar, which can be any suitable pressure. The oil at the P port overcomes the spring force of the spring 2 15, pushes the valve core 14 to the left end of the left reversing valve body 9 to form a cone seal, closes the B port and the T port, and the system begins to build pressure. When the pedal of the air brake valve 2 is released, the pressure at the P port begins to decrease. At the same time, under the action of the spring 2 15 and the pressure of the B chamber, the B port to the T port is gradually opened, and the pressure of the B chamber begins to decrease until the spring 2 15 reaches a new balance.

[0029] The connector 1 8 is provided with a T port, and the connector 3 17 is provided with a B port. When the spring force of the spring 2 15 plus the pressure of the B port is greater than the pressure of the P port, the B port is connected to the T port.

[0030] Embodiment 2:

[0031] A hydraulically controlled reversing valve is different from the embodiment 1 in that a gap seal is formed between the reversing valve body 9 and the valve core 14 .

[0032] Embodiment 3:

[0033] like Figure 3 As shown, a hydraulically controlled reversing valve is different from the embodiment 1 in that the reversing valve body 9 and the valve core 14 are sealed by an O-ring 16 .

[0034] Embodiment 4:

[0035] like Figure 2 As shown, a brake circulation system for a loader includes an air storage tank 1, an air brake valve 2, a booster pump 3, a brake caliper 5 and an oil tank 6, the air brake valve 2 is respectively connected to the air inlet of the booster pump 3 and the air storage tank 1, the brake circulation system for the loader also includes the hydraulically controlled reversing valve 4 as described in Example 1, the P port of the hydraulically controlled reversing valve 4 is connected to the high-pressure oil port of the booster pump 3, the A port is connected to the oil inlet of the brake caliper 5, the B port is connected to the oil outlet of the brake caliper 5, and the T port is connected to the oil tank 6.

[0036] A filter 7 is provided between the T port of the hydraulically controlled reversing valve 4 and the oil tank 6 , and the filter 7 can prevent the system from being blocked.

[0037] Embodiment 5:

[0038] A brake circulation system for a loader, which is different from Example 4 in that a filter element is provided between the P port of the hydraulically controlled reversing valve 4 and the high-pressure oil port of the booster pump 3, and the filter element can prevent the system from being blocked.

[0039] The working principle of the utility model is:

[0040] After the vehicle is started, the gas storage tank 1 is filled with gas. When braking, the air brake valve 2 is switched, and the gas enters the booster pump 3 and begins to build pressure. The pressure is output to the hydraulic control reversing valve 4. When the pressure at the P port is about p1-p2 bar (such as 3-6 bar), the one-way valve composed of the spring 11 and the one-way valve core 12 is closed. The valve core 14 in the hydraulic control reversing valve 4 does not move. At this time, the P port to the A port is not connected, and the B port to the T port is open. When the pressure continues to rise and exceeds p2 bar, due to the large right side area of ​​the valve core 14, the valve core 14 overcomes the spring force of the spring 2 15 and moves to the left until the valve core 14 combines with the end face of the reversing valve body 9 to form a cone seal, and the B port to the T port is cut off. Since the pressure at the P port is greater than p2 bar, the P port to the A port is connected, and the A port is connected to the inlet of the brake caliper 5. The oil enters the brake caliper 5. Since the B port to the T port is cut off, the brake system begins to build pressure and brakes.

[0041] When the brake pedal is released and a certain release angle is maintained, the pressure at the P port of the hydraulically controlled reversing valve 4 begins to drop to a certain value, such as the P port pressure drops from 120 bar to 100 bar. Figure 1As shown, the pressure at the right side P port of the valve core 14 in the hydraulically controlled reversing valve 4 decreases, while the pressure at the left side B chamber remains unchanged. Under the action of the spring force of the spring 2 15 and the pressure of the B chamber, it is reset. When the spring force and the force of the B chamber are greater than the right chamber pressure at P, the B port to the T port begins to be connected, and the pressure at the B port begins to decrease, such as the pressure at the B port decreases from 120 bar to about 110 bar. When the force at the P port is greater than the spring force of the spring 2 15 and the force at the B chamber, the hydraulically controlled reversing valve 4 is reversed again, and the B port to the T port is cut off to achieve a certain brake pressure release. Since there is a one-way valve from the P port to the A port, the oil will not flow from the A port to the P port. At the same time, the A port and the B port are connected, and circulate through the B port to the T port.

[0042] When the brake pedal is completely released, the pressure at the P port of the hydraulically controlled reversing valve 4 is 0 bar, the pressure at the P port on the right side of the valve core 14 in the hydraulically controlled reversing valve 4 is 0 bar, and the pressure at the B port on the left side is reduced to 0 bar. Under the action of the spring force of the spring 2 15, the valve core 14 moves from the left side to the right side, and the B port to the T port begins to be connected, the pressure at the A chamber and the B chamber is reduced to 0 bar, and the brake is released. At the same time, the A port and the B port are connected, and the oil returns from the B port to the T port, and the oil circulates.

Claims

1. A hydraulically controlled reversing valve, comprising a reversing valve body (9), characterized in that: The reversing valve body (9) is provided with a connector 1 (8), a one-way valve connector body (10), a connector 2 (13) and a connector 3 (17); a valve core (14) and a spring 2 (15) installed on the valve core (14) are provided in the reversing valve body (9); a spring 1 (11) and a one-way valve core (12) are provided in the one-way valve connector body (10).

2. The hydraulically controlled reversing valve according to claim 1, characterized in that: The second connector (13) is provided with a P port, and the one-way valve connector body (10) is provided with an A port. When the pressure at the P port is greater than x bar, the P port is connected to the A port.

3. The hydraulically controlled reversing valve according to claim 2, characterized in that: The connector one (8) is provided with a T port, and the connector three (17) is provided with a B port. When the spring force of the spring two (15) plus the pressure of the B port is greater than the pressure of the P port, the B port is connected to the T port.

4. The hydraulically controlled reversing valve according to any one of claims 1 to 3, characterized in that: A gap seal is formed between the reversing valve body (9) and the valve core (14).

5. The hydraulically controlled reversing valve according to any one of claims 1 to 3, characterized in that: The reversing valve body (9) and the valve core (14) are sealed via an O-ring (16).

6. A brake circulation system for a loader, comprising an air storage tank (1), an air brake valve (2), a booster pump (3), a brake caliper (5) and an oil tank (6), wherein the air brake valve (2) is connected to the air storage tank (1) and the booster pump (3), respectively, and characterized in that: The brake circulation system for the loader also includes the hydraulically controlled reversing valve (4) as described in claim 3, the P port of the hydraulically controlled reversing valve (4) is connected to the high-pressure oil port of the booster pump (3), the A port is connected to the oil inlet of the brake caliper (5), the B port is connected to the oil outlet of the brake caliper (5), and the T port is connected to the oil tank (6).

7. The brake circulation system for a loader according to claim 6, characterized in that: A filter (7) is provided between the T port of the hydraulically controlled reversing valve (4) and the oil tank (6).

8. The brake circulation system for a loader according to claim 6 or 7, characterized in that: A filter element is provided between the P port of the hydraulically controlled reversing valve (4) and the high-pressure oil port of the booster pump (3).

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