Brake valve group, hydraulic brake system and construction machinery

Abstract

The present invention relates to the field of hydraulic systems and provides a brake valve assembly, a hydraulic brake system, and engineering machinery, comprising a valve body, an accumulator, and a logic valve. The valve body is provided with a first oil inlet P1, a first oil return port T1, and a first working oil port. The accumulator is connected to the first working oil port, the first oil inlet P1, and the first oil return port T1. A logic valve is disposed between the accumulator and the first oil return port T1 and is provided with a first pilot oil port PP2, which is connected to the first oil inlet P1. When the brake valve assembly is applied to a hydraulic brake system and the hydraulic brake system is in operation, hydraulic oil flows through the first oil inlet P1 to the first pilot oil port PP2, and the logic valve cuts off the connection between the accumulator and the first oil return port T1. When the hydraulic brake system is in an inoperative state, oil supply to the first oil inlet P1 is stopped, the logic valve connects the accumulator to the first oil return port T1, and the accumulator discharges oil to the first oil return port T1 through the logic valve, thereby relieving the accumulator pressure.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic systems, and in particular to a brake valve group, a hydraulic brake system and engineering machinery. Background Art

[0002] Currently, pneumatic brake systems are commonly used on small-tonnage construction machinery. However, pneumatic brakes have low braking torque and are not suitable for use on large-tonnage construction machinery. Hydraulic brake systems, on the other hand, offer high braking torque, a compact structure, and high reliability, making them widely used on large-tonnage construction machinery.

[0003] At present, hydraulic brake systems mostly use accumulators as auxiliary power sources and emergency power sources. When the hydraulic brake system needs to be repaired, the accumulator needs to be depressurized to protect the safety of the maintenance personnel. Or when the construction machinery is parked for a long time, the accumulator also needs to be depressurized to extend the service life of the accumulator.

[0004] In the related art, manual pressure relief is often used to relieve the pressure of the accumulator, which has certain safety hazards.

[0005] Therefore, how to solve the problem in the related art that the accumulator needs to be manually depressurized has become a technical problem that technicians in this field urgently need to solve. Summary of the Invention

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0007] To this end, the present invention provides a brake valve group for being arranged in a hydraulic brake system, comprising:

[0008] A valve body is provided with a first oil inlet P1, a first oil return port T1, a pilot oil outlet PP1 and n first working oil ports;

[0009] n accumulators, each of the n accumulators being connected to the n first working oil ports in a one-to-one correspondence, each of the n accumulators being connected to the first oil inlet P1 and the first oil return port T1, and one of the accumulators being connected to the pilot oil outlet PP1;

[0010] m logic valves, each of which is disposed between at least one of the accumulators and the first oil return port T1, and each of which is provided with a first pilot oil port PP2, which is in communication with the first oil inlet port P1;

[0011] When there is oil pressure at the first oil inlet P1, the logic valve switches to the first working position, and the logic valve cuts off the communication between the corresponding accumulator and the first oil return port T1. When there is no oil pressure at the first oil inlet P2, the logic valve switches to the second working position, and the logic valve connects the corresponding accumulator and the first oil return port T1.

[0012] Here, n is an integer greater than or equal to 1 and less than or equal to 3, and m is an integer greater than or equal to and less than or equal to n.

[0013] Preferably, the brake valve group provided according to the present invention further includes a first solenoid reversing valve, the first solenoid reversing valve including a second oil inlet P2, a second working oil port A4, and a second oil return port T2, the second oil inlet P2 being connected to the first oil inlet P1 and one of the accumulators, the second working oil port A4 being connected to the pilot oil outlet PP1, and the second oil return port T2 being connected to the first oil return port T1;

[0014] When the first electromagnetic reversing valve is located at the third working position, the second working oil port A4 is connected to the second oil inlet port P2. When the first electromagnetic reversing valve is located at the fourth working position, the second working oil port A4 is connected to the second oil return port T2.

[0015] Preferably, the brake valve group provided according to the present invention further includes a second solenoid reversing valve, the second solenoid reversing valve including a third oil inlet P3, a third working oil port A5, and a third oil return port T3, the third oil inlet P3 being connected to the first oil inlet P1 and one of the accumulators, the third working oil port A5 being connected to the first working oil port corresponding to the accumulator connected to the third oil inlet P3, and the third oil return port T3 being connected to the first oil return port T1;

[0016] When the second electromagnetic reversing valve is located at the fifth working position, the third working oil port A5 is connected to the third oil inlet port P3. When the second electromagnetic reversing valve is located at the sixth working position, the third working oil port A5 is connected to the third oil return port T3.

[0017] The present invention also provides a hydraulic brake system, comprising an oil supply assembly, a foot valve, a front axle brake assembly, a rear axle brake assembly, a parking brake assembly, a control unit, and the brake valve group as described above;

[0018] The front axle brake assembly and the rear axle brake assembly are both connected to the oil supply assembly through the foot valve and the brake valve group, the parking brake assembly is connected to the oil supply assembly through the brake valve group, and the front axle brake assembly, the rear axle brake assembly, the first solenoid reversing valve of the brake valve group, and the second solenoid reversing valve of the brake valve group are all electrically connected to the control unit.

[0019] Preferably, according to the hydraulic brake system provided by the present invention, the foot valve includes a second pilot oil port PP3, a manual control end, a fourth oil inlet, a fourth working oil port and a fourth oil return port T4, the second pilot oil port PP3 is connected to the pilot oil outlet PP1 of the brake valve group, the fourth oil inlet is connected to the first working oil port of the brake valve group, the fourth working oil port is connected to the front axle brake assembly and the rear axle brake assembly, and the fourth oil return port T4 is connected to the first oil return port T1 of the brake valve group;

[0020] The second pilot oil port PP3 and the manual control end are used to control the switching of the foot valve between the seventh working position and the eighth working position. When the foot valve is in the seventh working position, the fourth working oil port is connected to the fourth oil inlet port. When the foot valve is in the eighth working position, the fourth working oil port is connected to the fourth oil return port T4.

[0021] Preferably, according to the hydraulic brake system provided by the present invention, the front axle brake assembly includes:

[0022] Front axle brake cylinder;

[0023] a third solenoid reversing valve, the third solenoid reversing valve including a fifth oil inlet P6, a fifth working oil port A8, and a fifth oil return port T5; the fifth oil inlet P6 is connected to the fourth working oil port of the foot valve; the fifth working oil port A8 is connected to the rodless chamber of the front axle brake cylinder; the fifth oil return port T5 is connected to the hydraulic oil tank; and the electronic control end of the third solenoid reversing valve is electrically connected to the control unit;

[0024] When the third electromagnetic reversing valve is located at the ninth working position, the fifth working oil port A8 is connected to the fifth oil inlet port P6. When the third electromagnetic reversing valve is located at the tenth working position, the fifth working oil port A8 is connected to the fifth oil return port T5.

[0025] Preferably, according to the hydraulic brake system provided by the present invention, the rear axle brake assembly includes a rear service brake cylinder, and the rodless chamber of the rear service brake cylinder is connected to the fourth working oil port of the foot valve.

[0026] Preferably, according to the hydraulic brake system provided by the present invention, the parking brake assembly includes:

[0027] a rear parking brake cylinder, wherein a rodless chamber of the rear parking brake cylinder is provided with an elastic member for driving the piston rod to move toward the rod chamber, and the rod chamber of the rear parking brake cylinder is connected to the first working oil port of the brake valve assembly;

[0028] A quick-connect connector is connected to the rod chamber of the rear parking brake cylinder.

[0029] Preferably, according to the hydraulic brake system provided by the present invention, the oil supply component includes a constant pressure variable pump, and the oil inlet end of the oil supply component is connected to the hydraulic oil tank, and the oil outlet end of the oil supply component is connected to the first oil inlet P1 of the brake valve group.

[0030] The present invention further provides an engineering machine, comprising the brake valve group or the hydraulic brake system as described above.

[0031] One of the above technical solutions has the following advantages or beneficial effects.

[0032] The brake valve assembly provided by the present invention is for use in a hydraulic brake system and includes a valve body, n accumulators, and m logic valves, where n is an integer greater than or equal to 1 and less than or equal to 3, and m is an integer greater than or equal to and less than n. The valve body is provided with a first oil inlet P1, a first oil return port T1, a pilot oil outlet PP1, and n first working oil ports. The n accumulators are connected to the n first working oil ports in a one-to-one correspondence. Each of the n accumulators is connected to the first oil inlet P1 and the first oil return port T1, and one of the accumulators is connected to the pilot oil outlet PP1. Each logic valve is provided between at least one accumulator and the first oil return port T1 to control accumulator pressure relief. The logic valve is provided with a first pilot oil port PP2, which is connected to the first oil inlet P1. During use, the n accumulators are filled through the first oil inlet P1, and hydraulic oil from the n accumulators and the first working oil ports is discharged through the first working oil ports. When the brake valve assembly is applied to a hydraulic brake system and the hydraulic brake system is in operation, hydraulic oil reaches the first pilot oil port PP2 of the logic valve through the first oil inlet P1. The logic valve switches to the first operating position, disconnecting the corresponding accumulator from the first oil return port T1, and the accumulator operates normally. When the hydraulic brake system is in an inoperative state, oil supply to the first oil inlet P1 is stopped, the first pilot oil port PP2 of the logic valve loses oil pressure, and the system switches to the second operating position. The logic valve connects the corresponding accumulator to the first oil return port T1, and the accumulator unloads oil to the first oil return port T1 through the logic valve, thereby relieving accumulator pressure. The brake valve assembly provided by the present invention can realize the function of automatically relieving accumulator pressure after the hydraulic brake system stops operating.

[0033] Furthermore, in the hydraulic brake system and engineering machinery provided by the present invention, since both are provided with the brake valve group as described above, they have the same advantages as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0035] Figure 1 is a schematic diagram of a hydraulic brake system according to an embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram of a brake valve assembly according to an embodiment of the present invention;

[0037] Figure 3 This is a schematic diagram of a foot valve according to an embodiment of the present invention;

[0038] Figure 4 1 is a schematic diagram of a third electromagnetic reversing valve according to an embodiment of the present invention;

[0039] Reference numerals:

[0040] 1. Hydraulic oil tank; 2. Suction filter; 3. Stop valve; 4. Constant pressure variable pump; 5. High-pressure filter; 7. Rear service brake cylinder; 8. First pressure sensor; 9. Rear parking brake cylinder; 10. Quick connector; 11. Foot valve; 12. Third solenoid reversing valve; 13. Second pressure sensor; 14. Front axle brake cylinder; 15. Control unit; 17. First filter; 18. First logic valve; 19. Second check valve; 20. Rear brake accumulator; 21. Third pressure sensor; 22. Front brake accumulator; 23. Fourth pressure sensor; 24. Third one-way valve; 25. Second logic valve; 26. First pressure reducing valve; 27. First solenoid reversing valve; 28. Second filter; 29. ​​Second throttle plug; 30. Fifth pressure sensor; 31. Fourth one-way valve; 32. Second pressure reducing valve; 33. Second solenoid reversing valve; 34. First throttle plug; 35. Third pressure reducing valve; 36. Parking brake accumulator; 37. First one-way valve. DETAILED DESCRIPTION

[0041] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0042] The following combination Figures 1 to 4A brake valve group, a hydraulic brake system, and a construction machine according to some embodiments of the present invention are described.

[0043] Some embodiments of the present invention provide a brake valve group including a valve body, n accumulators, and m logic valves.

[0044] The valve body is provided with a first oil inlet P1, a first oil return port T1, a pilot oil outlet PP1 and n first working oil ports, where n is an integer greater than or equal to 1 and less than or equal to 3.

[0045] For example, when the brake valve group is set in a hydraulic brake system, the first oil inlet P1 can be connected to the oil supply component of the hydraulic brake system, the first oil return port T1 can be connected to the hydraulic oil tank 1 of the hydraulic brake system, the pilot oil outlet PP1 can be connected to the pilot oil port of the reversing valve in the hydraulic brake system, and there can be three first working oil ports, one of which can be used to communicate with the front axle brake assembly, one first working oil port can be used to communicate with the rear axle brake assembly, and one first working oil port can be used to communicate with the parking brake assembly.

[0046] The n accumulators are connected to the n first working oil ports in a one-to-one correspondence. Each accumulator is connected to the first oil inlet P1 and the first oil return port T1, and one of the accumulators is connected to the pilot oil outlet PP1.

[0047] For example, three accumulators can be provided, each connected to a corresponding first working oil port. These ports can be used to connect to the front axle brake assembly, the rear axle brake assembly, or the parking brake assembly. The accumulator is connected to the first oil inlet port P1, allowing the hydraulic brake system to charge the accumulator through the first oil inlet port P1. The accumulator is also connected to the first oil return port T1, allowing the accumulator to discharge oil through the first oil return port T1, completing the accumulator pressure relief operation.

[0048] Each of the m logic valves is positioned between at least one accumulator and the first oil return port T1, controlling the connection between the at least one accumulator and the first oil return port T1. The logic valve is provided with a first pilot oil port PP2, which is connected to the first oil inlet P1. When hydraulic oil reaches the first pilot oil port PP2 through the first oil inlet P1, the logic valve switches to the first operating position, disconnecting the corresponding accumulator from the first oil return port T1. When the first oil inlet P1 loses oil pressure, the first pilot oil port PP2 also loses oil pressure, switching the logic valve to the second operating position, connecting the corresponding accumulator to the first oil return port T1, and thus relieving pressure.

[0049] Here, m is an integer greater than or equal to 1 and less than or equal to n. For example, one logic valve may be provided, positioned between the three accumulators and the first oil return port T1. Alternatively, two logic valves may be provided, both connected to the first oil return port T1. The two accumulators may be connected to the two logic valves in a one-to-one correspondence, and the third accumulator may be connected to one of the logic valves, or to both logic valves. Alternatively, three logic valves may be provided, each connected to the three accumulators in a one-to-one correspondence, and all three logic valves may be connected to the first oil return port T1.

[0050] When the brake valve group is set in the hydraulic brake system and the hydraulic brake system is in working condition, the oil supply component of the hydraulic brake system supplies oil to the first oil inlet P1 of the valve body, and the hydraulic oil can reach the first pilot oil port PP2 through the first oil inlet P1, so that the logic valve works in the first working position. At this time, the logic valve cuts off the connection between the corresponding accumulator and the first oil return port T1. At this time, the oil supply component can charge the accumulator through the first oil inlet P1. The accumulator and the hydraulic oil passing through the first oil inlet P1 can output hydraulic oil to the corresponding first working oil port separately or simultaneously.

[0051] When the hydraulic brake system is in a non-working state, the first oil inlet P1 of the valve body of the brake valve group loses oil pressure. At the same time, the first pilot oil port PP2 of the logic valve also loses oil pressure. The logic valve switches to the second working position, connecting the corresponding accumulator and the first oil return port T1, achieving the effect of automatic pressure relief of the accumulator when the hydraulic brake system stops working.

[0052] The brake valve group provided by the present invention can realize the effect of automatic pressure relief of the accumulator when the hydraulic brake system is shut down, solving the problem in the related art that manual pressure relief is required when the hydraulic brake system is shut down or repaired.

[0053] In some embodiments of the present invention, the brake valve assembly further includes a first solenoid reversing valve 27, which includes a second oil inlet P2, a second operating oil port A4, and a second oil return port T2. The second oil inlet P2 of the first solenoid reversing valve 27 communicates with the first oil inlet P1 of the valve body and one of the accumulators. The second operating oil port A4 of the first solenoid reversing valve 27 communicates with the pilot oil outlet PP1 of the valve body. The second oil return port T2 of the first solenoid reversing valve 27 communicates with the first oil return port T1 of the valve body.

[0054] The first solenoid reversing valve 27 includes two working positions, namely the third working position and the fourth working position. When the first solenoid reversing valve 27 is in the third working position, the second working oil port A4 of the first solenoid reversing valve 27 is connected to the second oil inlet P2, and the connection between the second working oil port A4 of the first solenoid reversing valve 27 and the second oil return port T2 is cut off. At this time, the hydraulic oil in the first oil inlet P1 of the valve body and the accumulator connected to the first solenoid reversing valve 27 can reach the pilot oil outlet PP1 of the valve body through the first solenoid reversing valve 27.

[0055] When the first solenoid reversing valve 27 is in the fourth working position, that is, the position shown in the figure, the second working oil port A4 of the first solenoid reversing valve 27 is connected to the second oil return port T2, and the connection between the second working oil port A4 of the first solenoid reversing valve 27 and the second oil inlet P2 is cut off. At this time, the hydraulic oil in the pilot oil outlet PP1 can flow back to the hydraulic oil tank 1 through the first solenoid reversing valve 27 and the first oil return port T1 of the valve body.

[0056] In some embodiments of the present invention, the brake valve assembly further includes a second solenoid reversing valve 33, which includes a third oil inlet P3, a third operating oil port A5, and a third oil return port T3. The third oil inlet P3 of the second solenoid reversing valve 33 communicates with the first oil inlet P1 of the valve body and one of the accumulators. The third operating oil port A5 of the second solenoid reversing valve 33 communicates with the first operating oil port corresponding to the accumulator connected to the third oil inlet P3. The third oil return port T3 of the second solenoid reversing valve 33 communicates with the first oil return port T1 of the valve body.

[0057] The second solenoid reversing valve 33 includes two working positions, namely the fifth working position and the sixth working position. When the second solenoid reversing valve 33 is in the fifth working position, the third working oil port A5 of the second solenoid reversing valve 33 is connected to the third oil inlet port P3, and the connection between the third working oil port A5 of the second solenoid reversing valve 33 and the third oil return port T3 is cut off. At this time, the hydraulic oil in the first oil inlet port P1 of the valve body and the accumulator connected to the second solenoid reversing valve 33 can reach the first working oil port on the valve body corresponding to the accumulator through the second solenoid reversing valve 33.

[0058] When the second solenoid reversing valve 33 is in the fifth working position, that is, the position shown in the figure, the third working oil port A5 of the second solenoid reversing valve 33 is connected to the third oil return port T3, and the connection between the third working oil port A5 of the second solenoid reversing valve 33 and the third oil inlet port P3 is cut off. At this time, the hydraulic oil in the first working oil port connected to the second solenoid reversing valve 33 can flow back to the hydraulic oil tank 1 through the second solenoid reversing valve 33 and the first oil return port T1 of the valve body.

[0059] Some embodiments of the present invention further provide a hydraulic brake system, including an oil supply assembly, a foot valve 11, a front axle brake assembly, a rear axle brake assembly, a parking brake assembly, a control unit 15 and the above-mentioned brake valve group.

[0060] The front and rear axle brake assemblies can be connected to the brake valve assembly via a foot valve 11. The brake valve assembly is connected to the oil supply assembly. The brake valve assembly and foot valve 11 control the oil supply assembly to supply oil to the front and rear axle brake assemblies, thereby controlling the application or release of the brakes. The parking brake assembly is directly connected to the brake valve assembly, which controls the oil supply assembly to supply oil to the parking brake assembly, thereby controlling the application or release of the parking brake assembly.

[0061] The front and rear axle brake assemblies, as well as the first and second electromagnetic reversing valves 27 and 33 of the brake valve group, are all electrically connected to the control unit 15. Under the control of the control unit 15, the hydraulic brake system can adapt to braking under various operating conditions, enabling the construction machinery to perform various actions, including accumulator charging, parking brake release, parking brake, loading brake, emergency brake, service brake, automatic accumulator decompression, pressure detection, and warning.

[0062] Since the hydraulic brake system provided by the embodiment of the present invention is provided with the brake valve group as described above, the hydraulic brake system can perform the various actions described above to cope with various working conditions.

[0063] In some embodiments of the present invention, the foot valve 11 may include a second pilot oil port PP3, a manual control port, a fourth oil inlet, a fourth working oil port, and a fourth oil return port T4. The second pilot oil port PP3 communicates with the pilot oil outlet PP1 of the brake valve assembly, the fourth oil inlet communicates with the first working oil port of the brake valve assembly, the fourth working oil port communicates with the front axle brake assembly and the rear axle brake assembly, and the fourth oil return port T4 communicates with the first oil return port T1 of the brake valve assembly.

[0064] Specifically, the first working oil port on the valve body of the brake valve group may include a first front axle brake oil port A1 , a first rear axle brake oil port A2 , and a parking brake oil port A3 .

[0065] The fourth oil inlet on the foot valve 11 may include the rear axle oil inlet P5 and the front axle oil inlet P4, and the fourth working oil port on the foot valve 11 may include the second front axle brake oil port A6 and the second rear axle brake oil port A7.

[0066] The second pilot oil port PP3 of the foot valve 11 communicates with the pilot oil outlet PP1 of the valve body. Hydraulic oil flowing through the pilot oil outlet PP1 controls the switching of the foot valve 11 between the seventh and eighth working positions. The manual control terminal of the foot valve 11 is connected to the brake pedal, allowing the driver to control the switching of the foot valve 11 between the seventh and eighth working positions by depressing the brake pedal.

[0067] The rear axle oil inlet P5 of the foot valve 11 is connected to the first rear axle brake oil port A2 of the valve body, the front axle oil inlet P4 of the foot valve 11 is connected to the first front axle brake oil port A1 of the valve body, the second front axle brake oil port A6 of the foot valve 11 is connected to the front axle brake assembly, and the second rear axle brake oil port A7 of the foot valve 11 is connected to the rear axle brake assembly.

[0068] When there is oil pressure at the second pilot oil port PP3 of the foot valve 11 or the brake pedal is stepped on, the foot valve 11 switches to the seventh working position, that is, the left position of the foot valve 11 shown in the figure. At this time, the second front axle brake oil port A6 of the foot valve 11 is connected to the front axle oil inlet P4, and the second rear axle brake oil port A7 of the foot valve 11 is connected to the rear axle oil inlet P5.

[0069] The hydraulic oil supplied by the oil supply assembly and the hydraulic oil of the accumulator corresponding to the first front axle brake oil port A1 are supplied to the front axle oil inlet P4 of the foot valve 11 through the first front axle brake oil port A1. After the hydraulic oil flows through the foot valve 11, it is supplied to the front axle brake assembly through the second front axle brake oil port A6 of the foot valve 11.

[0070] Similarly, the hydraulic oil supplied by the oil supply assembly and the hydraulic oil of the accumulator corresponding to the first rear axle brake oil port A2 are supplied to the rear axle oil inlet P5 of the foot valve 11 through the first rear axle brake oil port A2. After the hydraulic oil flows through the foot valve 11, it is supplied to the rear axle brake assembly through the second rear axle brake oil port A7 of the foot valve 11.

[0071] When the second pilot oil port PP3 of the foot valve 11 loses oil pressure or the brake pedal returns to its original position, the foot valve 11 switches to the eighth working position, that is, the position shown in the figure. At this time, the second front axle brake oil port A6 of the foot valve 11 and the front axle oil inlet P4 are cut off, and the second rear axle brake oil port A7 of the foot valve 11 and the rear axle oil inlet P5 are cut off.

[0072] In some embodiments of the present invention, the front axle brake assembly includes a front axle brake cylinder 14 and a third solenoid reversing valve 12. The third solenoid reversing valve 12 includes a fifth oil inlet P6, a fifth operating oil port A8, and a fifth oil return port T5. The fifth oil inlet P6 of the third solenoid reversing valve 12 communicates with the second front axle brake oil port A6 of the foot valve 11. The fifth operating oil port A8 of the third solenoid reversing valve 12 communicates with the rodless chamber of the front axle brake cylinder 14. The fifth oil return port T5 communicates with the hydraulic oil tank 1. The third solenoid reversing valve 12 communicates with the control unit 15.

[0073] During operation, the control unit 15 controls the third solenoid reversing valve 12 to switch between the ninth and tenth operating positions based on the working conditions of the construction machinery. When the third solenoid reversing valve 12 is switched to the ninth operating position (as shown), the fifth operating oil port A8 communicates with the fifth oil inlet port P6. Hydraulic oil from the second front axle brake oil port A6 can pass through the third solenoid reversing valve 12 and enter the rodless chamber of the front axle brake cylinder 14, causing the front axle brake cylinder 14 to extend, applying brakes to the front axle.

[0074] When the third solenoid reversing valve 12 switches to the tenth working position, that is, the lower position of the third solenoid reversing valve 12 as shown in the figure, the fifth working oil port A8 is connected to the fifth return oil port T5, and the hydraulic oil in the rodless chamber of the front axle brake cylinder 14 can flow back to the hydraulic oil tank 1 through the third solenoid reversing valve 12, and the front axle brake is released.

[0075] In some embodiments of the present invention, the rear axle brake assembly includes a rear service brake cylinder 7, the rodless chamber of which is connected to the second rear axle brake port A7 of the foot valve 11. When the foot valve 11 is in the left position, hydraulic oil can enter the rodless chamber of the rear service brake cylinder 7 through the second rear axle brake port A7 of the foot valve 11, causing the rear service brake cylinder 7 to extend and apply brakes to the rear axle. When the foot valve 11 is in the right position, the hydraulic oil in the rodless chamber of the rear service brake cylinder 7 flows back into the hydraulic oil tank 1 through the foot valve 11, releasing the rear axle brakes.

[0076] In some embodiments of the present invention, the parking brake assembly includes a rear parking brake cylinder 9 and a quick connector 10. The rod chamber of the rear parking brake cylinder 9 is connected to the parking brake oil port A3 of the valve body, and a spring is disposed in the rodless chamber of the rear parking brake cylinder 9.

[0077] When the brake valve assembly's parking brake port A3 is not outputting hydraulic pressure, the spring in the rodless chamber of the rear parking brake cylinder 9 drives it to extend, braking the rear axle. When the brake valve assembly's parking brake port A3 is outputting hydraulic pressure, hydraulic oil enters the rod chamber of the rear parking brake cylinder 9. The hydraulic oil pressure overcomes the spring force, driving the rear parking brake cylinder 9 to retract, releasing the parking brake.

[0078] However, when the hydraulic brake system malfunctions and the parking brake oil port A3 of the brake valve assembly is unable to output hydraulic oil, the parking brake cannot be released, resulting in the construction machinery being unable to move. To address this technical problem, the hydraulic brake system is provided with a quick-connect connector 10, which is connected to the rod chamber of the rear parking brake cylinder 9. When the hydraulic system is unable to supply oil pressure to the rod chamber of the rear parking brake cylinder 9, the quick-connect connector 10 can be connected to an external hydraulic oil source to output oil pressure to the rod chamber of the rear parking brake cylinder 9, thereby releasing the parking brake.

[0079] In some embodiments of the present invention, the oil supply assembly's oil inlet is connected to the hydraulic oil tank 1, and its oil outlet is connected to the first oil inlet P1 of the brake valve assembly. The oil supply assembly utilizes a constant-pressure variable pump 4. Once the accumulator is fully charged, the constant-pressure variable pump 4 stops supplying oil, reducing heat generation in the hydraulic brake system.

[0080] A specific embodiment will be disclosed below to illustrate various working modes of the hydraulic brake system.

[0081] In this embodiment, the brake valve assembly includes a first oil inlet P1, a first oil return port T1, a first working oil port, a pilot oil outlet PP1, an accumulator, a logic valve, and a solenoid reversing valve. The first working oil port includes a first front axle brake oil port A1, a first rear axle brake oil port A2, and a parking brake oil port A3. The accumulator includes a front brake accumulator 22, a rear brake accumulator 20, and a parking brake accumulator 36. The logic valve includes a first logic valve 18 and a second logic valve 25. The solenoid reversing valve includes a first solenoid reversing valve 27 and a second solenoid reversing valve 33. The first solenoid reversing valve 27 includes a second oil inlet P2, a second oil return port T2, and a second working oil port A4. The second solenoid reversing valve 33 includes a third oil inlet P3, a third oil return port T3, and a third working oil port A5.

[0082] The foot valve 11 includes a second pilot oil port PP3, a manual control port, a fourth oil inlet, a fourth working oil port, and a fourth oil return port T4. The fourth oil inlet includes the front axle oil inlet P4 and the rear axle oil inlet P5, and the fourth oil outlet includes the second front axle brake oil port A6 and the second rear axle brake oil port A7.

[0083] The hydraulic brake system provided in this embodiment can achieve the following functions:

[0084] First, accumulator filling

[0085] The constant pressure variable pump 4 draws hydraulic oil from the hydraulic oil tank 1 through the oil suction filter 2 and the stop valve 3. The oil outlet of the constant pressure variable pump 4 enters the high-pressure filter 5 and is supplied to the first oil inlet P1 of the brake valve group. It passes through the first one-way valve 37, the third pressure reducing valve 35, the second one-way valve 19, and the third one-way valve 24, and at the same time fills the rear brake accumulator 20, the front brake accumulator 22 and the parking brake accumulator 36.

[0086] The constant pressure variable pump 4 has a pressure cut-off function. When the accumulator is fully charged, the pressure cut-off function of the constant pressure variable pump 4 is activated and no flow is output, thereby reducing the heat generated by the system.

[0087] Second, release the parking

[0088] A parking release command is input to the control unit 15, which outputs a control signal to the second solenoid reversing valve 33, causing the second solenoid reversing valve 33 to be electrically reversed, i.e., the second solenoid reversing valve 33 is in the lower position as shown in the figure. High-pressure oil passes through the second solenoid reversing valve 33 and the second pressure reducing valve 32, and is input to the rear parking brake cylinder 9 through the parking brake oil port A3 of the brake valve group and the quick-connect connector 10, thereby achieving parking release.

[0089] Third, parking brake

[0090] The parking brake command is input to the control unit 15, and the control unit 15 outputs a control signal to the second solenoid reversing valve 33, controlling the second solenoid reversing valve 33 to lose power and reverse (as shown in the figure). Under the action of the spring, the pressure oil in the rear parking brake cylinder 9 enters the brake valve group through the quick-connect connector 10 and the parking brake oil port A3 of the brake valve group, and returns to the hydraulic oil tank 1 through the second pressure reducing valve 32, the fourth one-way valve 31, the second solenoid reversing valve 33 and the first oil return port T1 of the brake valve group, thereby realizing the parking brake function.

[0091] Fourth, loading brake

[0092] When loading, the dump truck needs to implement loading braking, and inputs a loading braking instruction to the control unit 15. The control unit 15 outputs a control signal to the first solenoid reversing valve 27 and the third solenoid reversing valve 12, controlling the first solenoid reversing valve 27 to be energized and switched to the right position, and at the same time controlling the third solenoid reversing valve 12 to be energized and switched to the upper position.

[0093] The pressure oil output by the constant pressure variable pump 4 and the front brake accumulator 22 passes through the first pressure reducing valve 26 and the first solenoid reversing valve 27, and acts on the second pilot oil port PP3 of the foot valve 11, causing the valve core of the foot valve 11 to reverse, that is, switch to the left position shown in the figure.

[0094] The pressure oil from the constant pressure variable pump 4 and the rear brake accumulator 20 enters the rear axle oil inlet P5 of the foot valve 11 through the first rear axle brake oil port A2 of the brake valve group, and is output from the second rear axle brake oil port A7 of the foot valve 11, acting on the rodless chamber of the rear service brake cylinder 7, and the rear axle enters the braking state.

[0095] The pressure oil from the constant pressure variable pump 4 and the front brake accumulator 22 enters the front axle oil inlet P4 of the foot valve 11 through the first front axle brake oil port A1 of the brake valve group, and is output from the second front axle brake oil port A6 of the foot valve 11. At this time, since the third solenoid reversing valve 12 is energized and reversed, the pressure oil output from the second front axle brake oil port A6 of the foot valve 11 is cut off at the third solenoid reversing valve 12 and does not act on the front axle brake cylinder 14. The pressure oil in the front axle brake cylinder 14 is connected to the hydraulic oil tank 1 through the third solenoid reversing valve 12 and is in a pressure relief state, so the front axle is in a brake release state.

[0096] Fifth, emergency braking

[0097] Under hazardous working conditions, this hydraulic braking system has an emergency braking function, that is, the front axle service brake, rear axle service brake and parking brake are implemented simultaneously.

[0098] An emergency braking command is input to the control unit 15, and the control unit 15 outputs a control signal to the first solenoid reversing valve 27, the second solenoid reversing valve 33 and the third solenoid reversing valve 12, controlling the first solenoid reversing valve 27 to be energized and reversing, so that the first solenoid reversing valve 27 is in the right position shown in the figure, and at the same time controlling the second solenoid reversing valve 33 and the third solenoid reversing valve 12 to be in a de-energized state, so that the second solenoid reversing valve 33 is in the position shown in the figure, and the third solenoid reversing valve 12 is in the position shown in the figure.

[0099] The pressure oil output by the constant pressure variable pump 4 and the front brake accumulator 22 passes through the first pressure reducing valve 26 and the first solenoid reversing valve 27, and acts on the second pilot oil port PP3 of the foot valve 11, so that the valve core of the foot valve 11 is reversed and located in the left position of the foot valve 11 as shown in the figure.

[0100] The pressure oil from the constant pressure variable pump 4 and the rear brake accumulator 20 enters the rear axle oil inlet P5 of the foot valve 11 through the first rear axle brake oil port A2 of the brake valve group, and is output by the second rear axle brake oil port A7 of the foot valve 11, acting on the rodless chamber of the rear service brake cylinder 7, and the rear axle enters the braking state.

[0101] The pressure oil from the constant pressure variable pump 4 and the front brake accumulator 22 enters the front axle oil inlet P4 of the foot valve 11 through the first front axle brake oil port A1 of the brake valve group, and is output by the second front axle brake oil port A6 of the foot valve 11. At this time, since the third solenoid reversing valve 12 is in the lower position, the pressure oil output from the second front axle brake oil port A6 of the foot valve 11 passes through the third solenoid reversing valve 12 and acts on the rodless chamber of the front axle brake cylinder 14, and the front axle enters the braking state.

[0102] Since the second solenoid reversing valve 33 loses power and is in the upper position as shown in the figure, the pressure oil from the constant pressure variable pump 4 and the parking brake accumulator 36 is cut off at the second solenoid reversing valve 33 and does not act on the rear parking brake cylinder 9. Under the action of the internal mechanical force of the brake, the oil in the rod chamber of the rear parking brake cylinder 9 enters the brake valve group through the quick-connect connector 10 and the parking brake oil port A3 of the brake valve group, passes through the second pressure reducing valve 32, the fourth one-way valve 31, and the second solenoid reversing valve 33, and returns to the hydraulic oil tank 1 from the first oil return port T1 of the brake valve group, thereby realizing the parking brake function.

[0103] 6. Service Braking

[0104] During driving, the driver steps on the brake pedal, so that the manual control end of the foot valve 11 controls the valve core of the foot valve 11 to reverse, so that the foot valve 11 is located in the left position of the foot valve 11 shown in the figure, and the front axle brake assembly and the rear axle brake assembly simultaneously implement service braking.

[0105] The pressure oil from the constant pressure variable pump 4 and the rear brake accumulator 20 enters the rear axle oil inlet P5 of the foot valve 11 through the first rear axle brake oil port A2 of the brake valve group, and is output by the second rear axle brake oil port A7 of the foot valve 11, acting on the rodless chamber of the rear service brake cylinder 7, and the rear axle enters the service braking state.

[0106] The pressure oil from the constant pressure variable pump 4 and the front brake accumulator 22 enters the front axle oil inlet P4 of the foot valve 11 through the first front axle brake oil port A1 of the brake valve group, and is output from the second front axle brake oil port A6 of the foot valve 11. At this time, since the third solenoid reversing valve 12 is located in the lower position shown in the figure, the pressure oil output from the second front axle brake oil port A6 of the foot valve 11 passes through the third solenoid reversing valve 12 and acts on the rodless chamber of the front axle brake cylinder 14, thereby realizing service braking of the front axle.

[0107] Seventh, automatic pressure relief of shutdown accumulator

[0108] In the shutdown state, after the outlet pressure of the constant pressure variable pump 4 is released, the pressure at the first pilot oil port PP2 of the first logic valve 18 and the second logic valve 25 also disappears, and the valve cores of the first logic valve 18 and the second logic valve 25 are in the right connection position under the action of the spring force.

[0109] The pressure oil in the rear brake accumulator 20 passes through the first logic valve 18, the first filter 17, the first throttle plug 34, and returns to the hydraulic oil tank 1 via the first oil return port T1 of the brake valve group, completing the pressure relief.

[0110] The pressure oil in the front brake accumulator 22 passes through the second logic valve 25, the second filter 28, the second throttle plug 29, and returns to the hydraulic oil tank 1 via the first oil return port T1 of the brake valve group, completing the pressure relief.

[0111] The pressure oil in the parking brake accumulator 36 passes through the second one-way valve 19, the third one-way valve 24, the first logic valve 18, the second logic valve 25, the first filter 17, the second filter 28, the first throttle plug 34 and the second throttle plug 29, and returns to the hydraulic oil tank 1 through the first oil return port T1 of the brake valve group, completing the pressure relief.

[0112] 8. Pressure detection and warning

[0113] The hydraulic brake system is designed with a control unit 15, a screen display, function buttons and other devices for pressure collection, display, alarm and other functions.

[0114] The first pressure sensor 8 is used to detect the rear axle service brake pressure. The control unit 15 can identify whether the rear axle is braked, which is indicated by a corresponding on-screen indicator light.

[0115] The second pressure sensor 13 is used to detect the front axle service brake pressure. The control unit 15 can identify whether the system is in a loading brake state or an emergency brake state based on the collected pressure value, and display it on the corresponding screen indicator light.

[0116] The third pressure sensor 21 is used to detect the pressure of the rear brake accumulator 20, which is displayed by a corresponding on-screen indicator light.

[0117] The fourth pressure sensor 23 is used to detect the pressure of the front brake accumulator 22, which is displayed by a corresponding on-screen indicator light.

[0118] The fifth pressure sensor 30 is used to detect the pressure of the rod chamber of the rear parking brake cylinder 9, and is used to distinguish whether the parking brake is applied or released, which is displayed by the corresponding on-screen indicator light.

[0119] 9. Emergency parking release

[0120] The hydraulic brake system is designed with a quick-connect connector 10. When the hydraulic brake system loses power, it can be connected to an external power source (hand pump, rescue vehicle, etc.) through the quick-connect connector 10 to quickly complete the parking release and supply emergency towing.

[0121] Furthermore, an embodiment of the present invention also provides an engineering machinery, which may be a dump truck, an excavator, a crane, etc. Since they are all provided with the brake valve group or the hydraulic brake system as described above, they have the same advantages as described above.

[0122] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A brake valve assembly, used to be arranged in a hydraulic brake system, characterized in that: include: A valve body is provided with a first oil inlet P1, a first oil return port T1, a pilot oil outlet PP1 and n first working oil ports; n accumulators, each of the n accumulators being connected to the n first working oil ports in a one-to-one correspondence, each of the n accumulators being connected to the first oil inlet P1 and the first oil return port T1, and one of the accumulators being connected to the pilot oil outlet PP1; m logic valves, each of which is disposed between at least one of the accumulators and the first oil return port T1, and each of which is provided with a first pilot oil port PP2, which is in communication with the first oil inlet port P1; a first electromagnetic reversing valve (27), the first electromagnetic reversing valve (27) comprising a second oil inlet P2, a second working oil port A4, and a second oil return port T2, the second oil inlet P2 being connected to the first oil inlet P1 and one of the accumulators, the second working oil port A4 being connected to the pilot oil outlet PP1, and the second oil return port T2 being connected to the first oil return port T1; When the first electromagnetic reversing valve (27) is located in the third working position, the second working oil port A4 is connected to the second oil inlet port P2; when the first electromagnetic reversing valve (27) is located in the fourth working position, the second working oil port A4 is connected to the second oil return port T2; When there is oil pressure at the first oil inlet P1, the logic valve switches to the first working position, and the logic valve cuts off the communication between the corresponding accumulator and the first oil return port T1. When there is no oil pressure at the first oil inlet P1, the logic valve switches to the second working position, and the logic valve connects the corresponding accumulator and the first oil return port T1. Here, n is an integer greater than or equal to 1 and less than or equal to 3, and m is an integer greater than or equal to 1 and less than or equal to n.

2. The brake valve assembly according to claim 1, characterized in that: The invention also includes a second electromagnetic reversing valve (33), the second electromagnetic reversing valve (33) including a third oil inlet P3, a third working oil port A5 and a third oil return port T3, the third oil inlet P3 being connected to the first oil inlet P1 and one of the accumulators, the third working oil port A5 being connected to the first working oil port corresponding to the accumulator connected to the third oil inlet P3, and the third oil return port T3 being connected to the first oil return port T1; When the second electromagnetic reversing valve (33) is located at the fifth working position, the third working oil port A5 is connected to the third oil inlet port P3; when the second electromagnetic reversing valve (33) is located at the sixth working position, the third working oil port A5 is connected to the third oil return port T3.

3. A hydraulic brake system, characterized in that: It comprises an oil supply assembly, a foot valve (11), a front axle brake assembly, a rear axle brake assembly, a parking brake assembly, a control unit (15) and the brake valve group as claimed in claim 2; The front axle brake assembly and the rear axle brake assembly are both connected to the oil supply assembly via the foot valve (11) and the brake valve group; the parking brake assembly is connected to the oil supply assembly via the brake valve group; the front axle brake assembly, the rear axle brake assembly, the first electromagnetic reversing valve (27) of the brake valve group, and the second electromagnetic reversing valve (33) of the brake valve group are all electrically connected to the control unit (15).

4. The hydraulic brake system according to claim 3, characterized in that: The foot valve (11) comprises a second pilot oil port PP3, a manual control end, a fourth oil inlet, a fourth working oil port and a fourth oil return port T4, wherein the second pilot oil port PP3 is communicated with the pilot oil outlet PP1 of the brake valve group, the fourth oil inlet is communicated with the first working oil port of the brake valve group, the fourth working oil port is communicated with the front axle brake assembly and the rear axle brake assembly, and the fourth oil return port T4 is communicated with the first oil return port T1 of the brake valve group; The second pilot oil port PP3 and the manual control end are used to control the switching of the foot valve (11) between the seventh working position and the eighth working position. When the foot valve (11) is located in the seventh working position, the fourth working oil port is communicated with the fourth oil inlet port. When the foot valve (11) is located in the eighth working position, the fourth working oil port is communicated with the fourth oil return port T4.

5. The hydraulic brake system according to claim 4, characterized in that: The front axle brake assembly includes: Front axle brake cylinder (14); a third electromagnetic reversing valve (12), the third electromagnetic reversing valve (12) comprising a fifth oil inlet P6, a fifth working oil port A8 and a fifth oil return port T5, the fifth oil inlet P6 being in communication with the fourth working oil port of the foot valve (11), the fifth working oil port A8 being in communication with the rodless chamber of the front axle brake cylinder (14), the fifth oil return port T5 being in communication with the hydraulic oil tank (1), and the electric control end of the third electromagnetic reversing valve (12) being electrically connected to the control unit (15); When the third electromagnetic reversing valve (12) is located at the ninth working position, the fifth working oil port A8 is communicated with the fifth oil inlet port P6; when the third electromagnetic reversing valve (12) is located at the tenth working position, the fifth working oil port A8 is communicated with the fifth oil return port T5.

6. The hydraulic brake system according to claim 4, characterized in that: The rear axle brake assembly comprises a rear service brake oil cylinder (7), and the rodless chamber of the rear service brake oil cylinder (7) is communicated with the fourth working oil port of the foot valve (11).

7. The hydraulic brake system according to claim 3, characterized in that: The parking brake assembly comprises: A rear parking brake oil cylinder (9), wherein a rodless chamber of the rear parking brake oil cylinder (9) is provided with an elastic member for driving a piston rod to move toward a rod chamber, and the rod chamber of the rear parking brake oil cylinder (9) is connected to a first working oil port of the brake valve group; A quick-connect connector (10) is connected to the rod chamber of the rear parking brake oil cylinder (9).

8. The hydraulic brake system according to claim 3, characterized in that: The oil supply assembly comprises a constant pressure variable plunger pump (4), and the oil inlet end of the oil supply assembly is in communication with the hydraulic oil tank (1), and the oil outlet end of the oil supply assembly is in communication with the first oil inlet port P1 of the brake valve group.

9. An engineering machine, characterized in that: It comprises the brake valve group according to any one of claims 1 to 2 or the hydraulic brake system according to any one of claims 3 to 8.

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