A hydraulic system for releasing a parking brake of a scraper in a underground goaf

Abstract

This utility model relates to a hydraulic system for releasing the parking brake of a loader in a mining goaf area, comprising: a front axle hydraulic device, a front axle two-position normally open valve, a front axle parking brake, a front axle two-position normally closed valve, a rear axle hydraulic device, a rear axle two-position normally open valve, a rear axle parking brake, a rear axle two-position normally closed valve, a first accumulator, a two-position three-position normally closed tow hook valve, a two-position three-position normally open valve, a pressure reducing valve, a hydraulically controlled check valve, a first two-position two-position normally closed valve, a second accumulator, an oil tank, and a return oil check valve; when the tractor and the loader are connected for towing, no additional power source needs to be temporarily installed, enabling efficient and rapid towing, and has pressure protection, allowing the loader to release the brake smoothly and safely.

Description

Technical Field

[0001] This utility model relates to the field of loader, specifically to a hydraulic system for releasing the parking brake of a loader used in mining goaf areas. Background Technology

[0002] Mining voids, often simply referred to as "mining voids," refer to the underground spaces left behind after mineral resources have been mined and not effectively filled.

[0003] A scraper is a high-efficiency, multi-functional self-propelled stone excavator that uses a bucket as its working device to scrape, load, transport, and unload materials or loose materials. When a scraper breaks down in a mining area, it needs to be towed by a tractor.

[0004] The existing hydraulic system for releasing the parking brake of a loader requires the temporary installation of an additional power source when the tractor and the loader are connected for towing, which makes it impossible to tow efficiently and quickly. Furthermore, it lacks pressure protection and cannot allow the loader to release the brake smoothly and safely.

[0005] The purpose of this invention is to design a hydraulic system for releasing the parking brake of a loader in a mining goaf area, addressing the problems existing in the prior art. Utility Model Content

[0006] In view of the problems existing in the prior art, the present invention provides a hydraulic system for releasing the parking brake of a loader in a mining goaf, which can effectively solve at least one of the problems existing in the prior art.

[0007] The technical solution of this utility model is: A hydraulic system for releasing the parking brake of a loader in a mining goaf area includes: Front axle hydraulic system, front axle two-position normally open valve, front axle parking brake, front axle two-position normally closed valve, rear axle hydraulic system, rear axle two-position normally open valve, rear axle parking brake, rear axle two-position normally closed valve, first accumulator, two-position three-position normally closed tow hook valve, two-position three-position normally open valve, pressure reducing valve, hydraulic check valve, first two-position two-position normally closed valve, second accumulator, oil tank, return oil check valve; The oil inlet and outlet of the two-position three-normally closed tow hook valve are respectively connected to the working oil port of the first accumulator and the oil inlet of the two-position three-normally open valve. The oil inlet of the pressure reducing valve and the oil inlet of the first two-position two-normally closed valve are both connected to the oil outlet of the two-position three-normally open valve. The control oil inlet of the first two normally closed valve and the oil inlet of the hydraulic check valve are both connected to the working oil inlet of the second accumulator. The return oil inlet and the first control oil inlet of the two normally open valve are both connected to the oil outlet of the hydraulic check valve. The front axle two-position normally closed valve is connected to the oil outlet of the pressure reducing valve and the front axle parking brake, and the rear axle two-position normally closed valve is connected to the oil outlet of the pressure reducing valve and the rear axle parking brake. The two normally open valves of the front axle are connected to the front axle hydraulic system and the front axle parking brake. The control port of the two normally open valves of the front axle and the control inlet of the two normally closed valves of the front axle are both connected to the outlet of the pressure reducing valve. The rear axle two-position normally open valve is connected to the rear axle hydraulic device and the rear axle parking brake. The control port of the rear axle two-position normally open valve and the control inlet of the rear axle two-position normally closed valve are both connected to the outlet of the pressure reducing valve. The oil inlet of the return oil check valve is connected to the oil outlet of the pressure reducing valve, and the oil outlet of the return oil check valve is connected to the oil outlet of the two-position three-position normally closed tow hook valve. The oil return port of the two-position three-position normally closed tow hook valve, the control oil return port of the two-position two-position normally closed valve of the front axle, the control oil return port of the two-position two-position normally closed valve of the rear axle, the oil discharge port of the pressure reducing valve, the control oil return port of the first two-position two-position normally closed valve, and the oil outlet of the first two-position two-position normally closed valve are all connected to the oil tank.

[0008] Furthermore, it also includes a first pressure switch, a second pressure switch, a compensating check valve, and a hydraulic power unit with a time delay relay; The first pressure switch is connected to the oil outlet of the two-position three-position normally closed tow hook valve. The oil inlet and oil outlet of the compensating check valve are connected to the oil outlet of the hydraulic power unit and the working oil port of the first accumulator, respectively. The second pressure switch is connected to the oil outlet of the compensating check valve. The oil inlet of the hydraulic power unit is connected to the oil tank.

[0009] Furthermore, it also includes normally closed solenoid control valves and rechargeable check valves; The oil inlet of the normally closed solenoid control valve is connected to the oil outlet of the compensation check valve, and the oil inlet and outlet of the energy replenishment check valve are respectively connected to the oil outlet of the normally closed solenoid control valve and the working oil port of the first accumulator.

[0010] Furthermore, it also includes an overflow valve; the oil inlet and oil outlet of the overflow valve are respectively connected to the oil outlet of the hydraulic power unit and the oil tank.

[0011] Furthermore, it also includes an adjustable flow valve; the oil inlet and oil outlet of the adjustable flow valve are respectively connected to the working oil port and oil tank of the first accumulator.

[0012] Furthermore, it also includes a first damping element; the first damping element is connected between the oil outlet of the return oil check valve and the oil outlet of the two-position three-way normally closed tow hook valve.

[0013] Furthermore, it also includes a second damping element; the second damping element is connected to the oil inlet of the first pressure switch and the two-position three-way normally open valve.

[0014] Furthermore, it also includes a third damping element; the third damping element is connected to the oil outlet of the adjustable flow valve and the oil tank.

[0015] Furthermore, it also includes a first pressure measuring point, a second pressure measuring point, a third pressure measuring point, a fourth pressure measuring point, a fifth pressure measuring point, and a pressure relief point; The first pressure measuring point is connected to the oil outlet of the pressure reducing valve, the second pressure measuring point is connected to the oil outlet of the two-position three-normally open valve, the third pressure measuring point is connected to the oil outlet of the two-position three-normally closed tow hook valve, the control oil port of the front axle two-position two-normally open valve and the control oil inlet of the front axle two-position two-normally closed valve are both connected to the fourth pressure measuring point, the fifth pressure measuring point is connected to the working oil port of the first accumulator, and the pressure relief point is connected to the working oil port of the second accumulator.

[0016] Furthermore, it also includes a pedal valve; the control port of the hydraulic check valve and the second control port of the two-position three-way normally open valve are both connected to the pedal valve.

[0017] Therefore, this utility model provides the following effects and / or advantages: 1) When the tractor unit is connected to the loader for trailer towing, no additional power source needs to be installed temporarily. It can trailer efficiently and quickly, and has pressure protection, which allows the loader to release the brake smoothly and safely.

[0018] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objectives and other advantages of this invention are realized and obtained through the structures particularly pointed out in the description and the accompanying drawings.

[0019] It should be understood that the above summary and the following detailed description of the present invention are exemplary and explanatory, and are intended to provide further explanation of the present invention as claimed. Attached Figure Description

[0020] Figure 1 This is a schematic diagram illustrating the principle of this utility model.

[0021] Explanation of reference numerals in the attached figures: Front axle hydraulic system 1, front axle two-position normally open valve 2, front axle parking brake 3, front axle two-position normally closed valve 4, rear axle hydraulic system 5, rear axle two-position normally open valve 6, rear axle parking brake 7, rear axle two-position normally closed valve 8, first accumulator 9, two-position three-position normally closed tow hook valve 10, two-position three-position normally open valve 11, pressure reducing valve 12, hydraulically controlled check valve 13, first two-position normally closed valve 14, second accumulator 15, oil tank 16, return oil slip 17. Pressure valve, 18. First pressure switch, 19. Second pressure switch, 20. Compensating check valve, 21. Hydraulic power unit, 22. Normally closed solenoid control valve, 23. Replenishing check valve, 24. Relief valve, 25. Adjustable flow valve, 26. First damping element, 27. Second damping element, 28. Third damping element, 29. First pressure measuring point, 30. Second pressure measuring point, 31. Third pressure measuring point, 32. Fourth pressure measuring point, 33. Fifth pressure measuring point, 34. Pressure relief point, 35. Foot pedal valve. Detailed Implementation

[0022] To facilitate understanding by those skilled in the art, the structure of this utility model will now be described in further detail with reference to the accompanying drawings: refer to Figure 1 A hydraulic system for releasing the parking brake of a loader in a mined-out area, comprising: 1. Front axle hydraulic system; 2. Front axle two-position normally open valve; 3. Front axle parking brake; 4. Front axle two-position normally closed valve; 5. Rear axle hydraulic system; 6. Rear axle two-position normally open valve; 7. Rear axle two-position normally closed valve; 8. First accumulator; 9. Two-position three-position normally closed tow hook valve; 10. Two-position three-position normally open valve; 11. Pressure reducing valve; 12. Hydraulic control check valve; 13. First two-position two-position normally closed valve; 14. Second accumulator; 15. Oil tank; 16. Return oil check valve; 17. The oil inlet and outlet of the two-position three-normally closed tow hook valve 10 are respectively connected to the working oil port of the first accumulator 9 and the oil inlet of the two-position three-normally open valve 11. The oil inlet of the pressure reducing valve 12 and the oil inlet of the first two-position two-normally closed valve 14 are both connected to the oil outlet of the two-position three-normally open valve 11. The control oil inlet of the first two normally closed valve 14 and the oil inlet of the hydraulic check valve 13 are both connected to the working oil port of the second accumulator 15. The return oil port and the first control oil port of the two normally open valve 11 are both connected to the oil outlet of the hydraulic check valve 13. The front axle two-position normally closed valve 4 is connected to the oil outlet of the pressure reducing valve 12 and the front axle parking brake 3, and the rear axle two-position normally closed valve 8 is connected to the oil outlet of the pressure reducing valve 12 and the rear axle parking brake 7. The front axle two-position normally open valve 2 is connected to the front axle hydraulic device 1 and the front axle parking brake 3. The control oil port of the front axle two-position normally open valve 2 and the control oil inlet of the front axle two-position normally closed valve 4 are both connected to the oil outlet of the pressure reducing valve 12. The rear axle two-position normally open valve 6 is connected to the rear axle hydraulic device 5 and the rear axle parking brake 7. The control oil port of the rear axle two-position normally open valve 6 and the control oil inlet of the rear axle two-position normally closed valve 8 are both connected to the oil outlet of the pressure reducing valve 12. The oil inlet of the return oil check valve 17 is connected to the oil outlet of the pressure reducing valve 12, and the oil outlet of the return oil check valve 17 is connected to the oil outlet of the two-position three-position normally closed tow hook valve 10. The oil return port of the two-position three-position normally closed tow hook valve 10, the control oil return port of the front axle two-position two-position normally closed valve 4, the control oil return port of the rear axle two-position two-position normally closed valve 8, the oil discharge port of the pressure reducing valve 12, the control oil return port of the first two-position two-position normally closed valve 14, and the oil outlet of the first two-position two-position normally closed valve 14 are all connected to the oil tank 16.

[0023] When the loader is in normal use, the front axle hydraulic device 1 outputs hydraulic oil, which flows through the front axle two-position normally open valve 2 to the front axle parking brake 3, and the front axle parking brake 3 is in the released state. The rear axle hydraulic device 5 outputs hydraulic oil, which flows through the rear axle two-position normally open valve 6 to the rear axle parking brake 7, and the rear axle parking brake 7 is in the released state.

[0024] When the loader malfunctions, neither the front axle hydraulic device 1 nor the rear axle hydraulic device 5 can output hydraulic oil, and the front axle parking brake 3 and the rear axle parking brake 7 will apply the brakes. When the loader malfunctions and the tractor is connected to the loader, the two-position three-position normally closed hook valve 10 is pulled, and the first accumulator 9 outputs hydraulic oil. The hydraulic oil passes through the two-position three-position normally closed hook valve 10, the two-position three-position normally open valve 11, and the pressure reducing valve 12 in sequence. The hydraulic oil from the outlet of the pressure reducing valve 12 flows to the control port of the front axle two-position two-position normally open valve 2, the control inlet of the front axle two-position two-position normally closed valve 4, the control port of the rear axle two-position two-position normally open valve 6, and the control inlet of the rear axle two-position two-position normally closed valve 8, thereby closing the front axle two-position two-position two-position normally open valve 2, opening the front axle two-position two-position two-position normally closed valve 4, closing the rear axle two-position two-position two-position normally open valve 6, and opening the rear axle two-position two-position two-position normally closed valve 8. The hydraulic oil flows through the front axle two-position two-position two-position normally closed valve 4 and the rear axle two-position two-position two-position normally closed valve 8 to the front axle parking brake 3 and the rear axle parking brake 7, thereby releasing the front axle parking brake 3 and the rear axle parking brake 7. The pressure reducing valve 12 ensures that the pressure of the hydraulic oil output by the first accumulator 9 meets the requirements of the front axle parking brake 3 and the rear axle parking brake 7, and ensures that the front axle parking brake 3 and the rear axle parking brake 7 can be released smoothly and safely.

[0025] When the tractor unit is towing the loader and the two-position three-position normally closed hook valve 10 is released, the second accumulator 15 outputs hydraulic oil. The hydraulic oil enters the control inlet of the first two-position two-position normally closed valve 14 and the inlet of the hydraulic control check valve 13, thereby opening the first two-position two-position normally closed valve 14 and closing the two-position three-position normally open valve 11. The two-position three-position normally open valve 11 is connected to the oil tank 16 through the first two-position two-position normally closed valve 14. When the tractor unit is towing the loader and the two-position three-position normally closed hook valve 10 is released, the hydraulic oil of the front axle parking brake 3 and the rear axle parking brake 7 returns to the oil tank 16 through the return oil check valve 17 and the two-position three-position normally closed hook valve 10.

[0026] It also includes a first pressure switch 18, a second pressure switch 19, a compensating check valve 20, and a hydraulic power unit 21 with a time delay relay; The first pressure switch 18 is connected to the oil outlet of the two-position three-position normally closed tow hook valve 10. The oil inlet and oil outlet of the compensating check valve 20 are connected to the oil outlet of the hydraulic power unit 21 and the working oil port of the first accumulator 9, respectively. The second pressure switch 19 is connected to the oil outlet of the compensating check valve 20. The oil inlet of the hydraulic power unit 21 is connected to the oil tank 16.

[0027] When the first accumulator 9 outputs hydraulic oil and the first pressure switch 18 detects that the hydraulic oil pressure at the outlet of the two-position three-position normally closed tow hook valve 10 is less than a predetermined value, the hydraulic power unit 21 is controlled by the second pressure switch 19 to output the hydraulic oil in the oil tank 16. The hydraulic power unit 21 shuts off after the hydraulic oil is output for a predetermined time.

[0028] It also includes a normally closed solenoid control valve 22 and a rechargeable check valve 23; The oil inlet of the normally closed solenoid control valve 22 is connected to the oil outlet of the compensation check valve 20, and the oil inlet and outlet of the energy replenishment check valve 23 are connected to the oil outlet of the normally closed solenoid control valve 22 and the working oil port of the first accumulator 9, respectively.

[0029] When the first accumulator 9 needs to be replenished with hydraulic oil, the normally closed solenoid control valve 22 opens and the second pressure switch 19 controls the hydraulic power unit 21 to output the hydraulic oil in the oil tank 16.

[0030] It also includes an overflow valve 24; the oil inlet and oil outlet of the overflow valve 24 are respectively connected to the oil outlet of the hydraulic power unit 21 and the oil tank 16.

[0031] The relief valve 24 releases excessive pressure when the hydraulic oil pressure output by the hydraulic power unit 21 is too high, thus providing a protective function.

[0032] It also includes an adjustable flow valve 25; the oil inlet and oil outlet of the adjustable flow valve 25 are respectively connected to the working oil port of the first accumulator 9 and the oil tank 16.

[0033] The adjustable flow valve 25 is used to open during maintenance of the loader to depressurize the first accumulator 9.

[0034] It also includes a first damping element 26; the first damping element 26 is connected between the oil outlet of the return oil check valve 17 and the oil outlet of the two-position three-way normally closed tow hook valve 10.

[0035] The first damping element 26 is used to ensure that the parking brake is applied smoothly when the tractor is towing the shovel and the two-position three-position normally closed hook valve 10 is released.

[0036] It also includes a second damping element 27; the second damping element 27 is connected to the oil inlet of the first pressure switch 18 and the two-position three-way normally open valve 11.

[0037] The second damping element 27 is used to achieve the effect of hydraulic damping.

[0038] It also includes a third damping element 28; the third damping element 28 is connected to the oil outlet of the adjustable flow valve 25 and the oil tank 16.

[0039] The third damping element 28 is used to achieve the effect of hydraulic damping.

[0040] It also includes the first pressure measuring point 29, the second pressure measuring point 30, the third pressure measuring point 31, the fourth pressure measuring point 32, the fifth pressure measuring point 33, and the pressure relief point 34; The first pressure measuring point 29 is connected to the oil outlet of the pressure reducing valve 12, the second pressure measuring point 30 is connected to the oil outlet of the two-position three-normally open valve 11, the third pressure measuring point 31 is connected to the oil outlet of the two-position three-normally closed tow hook valve 10, the control oil port of the front axle two-position two-normally open valve 2 and the control oil inlet of the front axle two-position two-normally closed valve 4 are both connected to the fourth pressure measuring point 32, the fifth pressure measuring point 33 is connected to the working oil port of the first accumulator 9, and the pressure relief point 34 is connected to the working oil port of the second accumulator 15.

[0041] The pressure relief point 34 is used to relieve pressure on the second accumulator 15.

[0042] It also includes a pedal valve 35; the control port of the hydraulic check valve 13 and the second control port of the two-position three-way normally open valve 11 are both connected to the pedal valve 35.

[0043] The first damping element 26, the second damping element 27, and the third damping element 28 are all throttle valves, speed control valves, or damping valves.

[0044] The hydraulic power unit 21 includes a hydraulic pump and a motor. The hydraulic pump is connected to the oil tank 16 and the motor is connected to the hydraulic pump. The motor drives the hydraulic pump to output the hydraulic oil in the oil tank 16.

[0045] It should be noted that any reference signs placed between parentheses in the claims should not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claims. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. This invention can be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names.

[0046] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0047] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0048] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms should not be construed as necessarily referring to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

Claims

1. A hydraulic system for releasing the parking brake of a loader used in a mined-out area, characterized in that: include: Front axle hydraulic system, front axle two-position normally open valve, front axle parking brake, front axle two-position normally closed valve, rear axle hydraulic system, rear axle two-position normally open valve, rear axle parking brake, rear axle two-position normally closed valve, first accumulator, two-position three-position normally closed tow hook valve, two-position three-position normally open valve, pressure reducing valve, hydraulic check valve, first two-position two-position normally closed valve, second accumulator, oil tank, return oil check valve; The oil inlet and outlet of the two-position three-normally closed tow hook valve are respectively connected to the working oil port of the first accumulator and the oil inlet of the two-position three-normally open valve. The oil inlet of the pressure reducing valve and the oil inlet of the first two-position two-normally closed valve are both connected to the oil outlet of the two-position three-normally open valve. The control oil inlet of the first two normally closed valve and the oil inlet of the hydraulic check valve are both connected to the working oil inlet of the second accumulator. The return oil inlet and the first control oil inlet of the two normally open valve are both connected to the oil outlet of the hydraulic check valve. The front axle two-position normally closed valve is connected to the oil outlet of the pressure reducing valve and the front axle parking brake, and the rear axle two-position normally closed valve is connected to the oil outlet of the pressure reducing valve and the rear axle parking brake. The two normally open valves of the front axle are connected to the front axle hydraulic system and the front axle parking brake. The control port of the two normally open valves of the front axle and the control inlet of the two normally closed valves of the front axle are both connected to the outlet of the pressure reducing valve. The rear axle two-position normally open valve is connected to the rear axle hydraulic device and the rear axle parking brake. The control port of the rear axle two-position normally open valve and the control inlet of the rear axle two-position normally closed valve are both connected to the outlet of the pressure reducing valve. The oil inlet of the return oil check valve is connected to the oil outlet of the pressure reducing valve, and the oil outlet of the return oil check valve is connected to the oil outlet of the two-position three-position normally closed tow hook valve. The oil return port of the two-position three-position normally closed tow hook valve, the control oil return port of the two-position two-position normally closed valve of the front axle, the control oil return port of the two-position two-position normally closed valve of the rear axle, the oil discharge port of the pressure reducing valve, the control oil return port of the first two-position two-position normally closed valve, and the oil outlet of the first two-position two-position normally closed valve are all connected to the oil tank.

2. The hydraulic system for releasing the parking brake of a loader in a mined-out area according to claim 1, characterized in that: It also includes a first pressure switch, a second pressure switch, a compensating check valve, and a hydraulic power unit with a time delay relay; The first pressure switch is connected to the oil outlet of the two-position three-position normally closed tow hook valve. The oil inlet and oil outlet of the compensating check valve are connected to the oil outlet of the hydraulic power unit and the working oil port of the first accumulator, respectively. The second pressure switch is connected to the oil outlet of the compensating check valve. The oil inlet of the hydraulic power unit is connected to the oil tank.

3. The hydraulic system for releasing the parking brake of a loader in a mined-out area according to claim 2, characterized in that: It also includes normally closed solenoid control valves and rechargeable check valves; The oil inlet of the normally closed solenoid control valve is connected to the oil outlet of the compensation check valve, and the oil inlet and outlet of the energy replenishment check valve are respectively connected to the oil outlet of the normally closed solenoid control valve and the working oil port of the first accumulator.

4. The hydraulic system for releasing the parking brake of a loader in a mined-out area according to claim 2, characterized in that: It also includes an overflow valve; the oil inlet and oil outlet of the overflow valve are respectively connected to the oil outlet of the hydraulic power unit and the oil tank.

5. The hydraulic system for releasing the parking brake of a loader in a mined-out area according to claim 1, characterized in that: It also includes an adjustable flow valve; the oil inlet and oil outlet of the adjustable flow valve are respectively connected to the working oil port and oil tank of the first accumulator.

6. The hydraulic system for releasing the parking brake of a loader in a mined-out area according to claim 1, characterized in that: It also includes a first damping element; the first damping element is connected between the oil outlet of the return oil check valve and the oil outlet of the two-position three-way normally closed tow hook valve.

7. A hydraulic system for releasing the parking brake of a loader in a mined-out area according to claim 2, characterized in that: It also includes a second damping element; the second damping element is connected to the oil inlet of the first pressure switch and the two-position three-way normally open valve.

8. A hydraulic system for releasing the parking brake of a loader in a mined-out area according to claim 5, characterized in that: It also includes a third damping element; the third damping element is connected to the oil outlet of the adjustable flow valve and the oil tank.

9. A hydraulic system for releasing the parking brake of a loader in a mined-out area according to claim 1, characterized in that: It also includes the first pressure measuring point, the second pressure measuring point, the third pressure measuring point, the fourth pressure measuring point, the fifth pressure measuring point, and the pressure relief point; The first pressure measuring point is connected to the oil outlet of the pressure reducing valve, the second pressure measuring point is connected to the oil outlet of the two-position three-normally open valve, the third pressure measuring point is connected to the oil outlet of the two-position three-normally closed tow hook valve, the control oil port of the front axle two-position two-normally open valve and the control oil inlet of the front axle two-position two-normally closed valve are both connected to the fourth pressure measuring point, the fifth pressure measuring point is connected to the working oil port of the first accumulator, and the pressure relief point is connected to the working oil port of the second accumulator.

10. A hydraulic system for releasing the parking brake of a loader in a mined-out area according to any one of claims 1-9, characterized in that: It also includes a pedal valve; the control port of the hydraulic check valve and the second control port of the two-position three-way normally open valve are both connected to the pedal valve.

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