Hydraulic brake systems and construction machinery

Abstract

The present invention relates to the field of braking systems and provides a hydraulic braking system and engineering machinery, comprising an oil supply device, n service brake assemblies, and a foot valve. At least one service brake assembly comprises a relay valve and a wet brake, and the relay valve is arranged between the oil supply device and the wet brake. The foot valve is arranged between the oil supply device and the control end of the relay valve and is used to control the connection or disconnection between the oil supply device and the control end of the relay valve. When the foot valve connects the oil supply device and the control end of the relay valve, the relay valve connects the oil supply device and the wet brake. At this time, the oil supply device can deliver hydraulic oil to the wet brake through the relay valve, so that the wet brake is in a braking state. The hydraulic braking system provided by the present invention controls the relay valve to connect or disconnect the oil supply device and the wet brake through the foot valve. When the relay valve connects the oil supply device and the wet brake, the oil supply device can provide sufficient hydraulic oil to the wet brake through the relay valve.

Description

Technical Field

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

[0002] As a key component of the entire construction machinery system, the performance of the braking system directly affects the efficiency of the entire machine operation, and is also related to the safety of life and property during the operation and movement of the entire machine.

[0003] Currently, dry brakes are commonly used in hydraulic braking systems for construction machinery. However, dry brakes have poor heat dissipation performance. As the friction pad temperature rises, thermal stability deteriorates, significantly impacting the driving and operational safety of the construction machinery. In contrast, wet brakes, with the friction pads housed in a coolant, dissipate heat through the coolant. Therefore, wet brakes offer high-temperature resistance, excellent heat dissipation, reduced wear, and superior thermal and braking stability.

[0004] However, in current hydraulic brake systems used for dry brakes, a foot valve is directly connected to the dry brake, controlling the flow of hydraulic oil to the dry brake to apply the brake. Since wet brakes require a higher flow rate of hydraulic oil, the foot valve cannot provide sufficient hydraulic oil if the dry brake is directly replaced with a wet brake. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0006] To this end, an embodiment of the present invention provides a hydraulic brake system, comprising:

[0007] Oil supply device;

[0008] n service brake assemblies, at least one of the service brake assemblies comprising a relay valve and a wet brake, wherein the relay valve is arranged between the oil supply device and the wet brake;

[0009] A foot valve, the foot valve being arranged between the oil supply device and the control ends of the n relay valves;

[0010] When the foot valve connects the oil supply device and the control end of the relay valve, the relay valve connects the oil supply device and the wet brake, and the wet brake is in a braking state;

[0011] Where n≥2.

[0012] Preferably, according to the hydraulic brake system provided by the present invention, the oil supply device includes:

[0013] Oil supply components;

[0014] A brake valve group, comprising a first oil inlet P1 and n first working oil ports A1;

[0015] The oil supply assembly is connected to the first oil inlet P1, the n relay valves are arranged one-to-one between the n first working oil ports A1 and the n wet brakes, and the foot valve is arranged between the n first working oil ports A1 and the control ends of the n relay valves.

[0016] Preferably, according to the hydraulic brake system provided by the present invention, the brake valve group includes a first electromagnetic reversing valve, and the brake valve group is provided with a first pilot oil port PP1, and the first electromagnetic reversing valve is arranged between the first oil inlet port P1 and the first pilot oil port PP1;

[0017] The foot valve is provided with a second pilot oil port PP2, which is connected to the first pilot oil port PP1;

[0018] When the first solenoid reversing valve connects the first oil inlet P1 and the first pilot oil port PP1 , oil pressure is established in the second pilot oil port PP2 , and the foot valve connects the first working oil port A1 and the corresponding control end of the relay valve.

[0019] Preferably, according to the hydraulic brake system provided by the present invention, the foot valve further includes a manual control end, and the manual control end is used to control the foot valve to connect or disconnect the first working oil port A1 and the corresponding control end of the relay valve.

[0020] Preferably, according to the hydraulic brake system provided by the present invention, the brake valve group further includes m second solenoid reversing valves, and the brake valve group is further provided with m third pilot oil ports PP3, the m third pilot oil ports PP3 are connected to the control ends of the m relay valves in a one-to-one correspondence, and the m second solenoid reversing valves are provided in a one-to-one correspondence between the first oil inlet P1 and the m third pilot oil ports PP3, and the second solenoid reversing valves are used to control the opening and closing of the corresponding third pilot oil ports PP3 and the first oil inlet P1;

[0021] When the second solenoid reversing valve connects the corresponding third pilot oil port PP3 to the first oil inlet P1, the corresponding relay valve connects the corresponding first working oil port A1 to the corresponding wet brake;

[0022] Where m≥1 and m≤n.

[0023] Preferably, according to the hydraulic brake system provided by the present invention, the brake valve group also includes m shuttle valves, and the brake valve group is also provided with m second oil inlets P2, the ninth oil inlet of the shuttle valve is connected to the corresponding second solenoid reversing valve, the tenth oil inlet of the shuttle valve is connected to the corresponding second oil inlet P2, the output oil port of the shuttle valve is connected to the corresponding third pilot oil port PP3, and the m first working oil ports A1 are connected one-to-one with the m second oil inlets P2 through the foot valve.

[0024] Preferably, the hydraulic braking system provided according to the present invention further includes a parking brake assembly, the brake valve group further includes a third solenoid reversing valve, and the brake valve group is also provided with a second working oil port A2 and a first oil return port T1. The third solenoid reversing valve is arranged between the first oil inlet P1, the second working oil port A2 and the first oil return port T1, and the second working oil port A2 is connected to the parking brake assembly. The third solenoid reversing valve is used to selectively connect the second working oil port A2 with the first oil inlet P1 or the first oil return port T1.

[0025] Preferably, according to the hydraulic brake system provided by the present invention, a quick-connect interface for connecting to an external oil source is further provided between the second working oil port A2 and the parking brake assembly.

[0026] Preferably, according to the hydraulic brake system provided by the present invention, an accumulator is connected to the channel between each of the first working oil ports A1 and the first oil inlet port P1;

[0027] Each accumulator is connected to the first oil return port T1 via a logic valve. The control end of the logic valve is connected to the first oil inlet P1. When there is oil pressure at the control end of the logic valve, the logic valve cuts off the connection between the corresponding accumulator and the first oil return port T1. When there is no oil pressure at the control end of the logic valve, the logic valve connects the corresponding accumulator and the first oil return port T1.

[0028] An embodiment of the present invention further provides an engineering machine, comprising the hydraulic brake system as described above.

[0029] One of the above technical solutions has the following advantages or beneficial effects.

[0030] A hydraulic brake system provided by an embodiment of the present invention includes an oil supply device, n service brake assemblies, and a foot valve. At least one service brake assembly includes a relay valve and a wet brake. The relay valve is disposed between the oil supply device and the wet brake and is used to control the connection or disconnection between the oil supply device and the wet brake. The foot valve is disposed between the oil supply device and the control end of the relay valve and is used to control the connection or disconnection between the oil supply device and the control end of the relay valve. When the foot valve connects the oil supply device to the control end of the relay valve, the relay valve connects the oil supply device to the wet brake. At this time, the oil supply device can deliver hydraulic oil to the wet brake through the relay valve, putting the wet brake into a braking state. Conversely, when the foot valve disconnects the oil supply device from the control end of the relay valve, the relay valve disconnects the oil supply device from the wet brake, resulting in a loss of oil pressure in the wet brake and a release of the brake. The hydraulic braking system provided by the present invention controls the relay valve through a foot valve to open or cut off the connection between the oil supply device and the wet brake. When the relay valve connects the oil supply device and the wet brake, the oil supply device can provide sufficient hydraulic oil to the wet brake through the relay valve, thereby solving the problem of insufficient hydraulic oil flow caused by providing hydraulic oil through a foot valve in related technologies.

[0031] Furthermore, in an engineering machine provided by an embodiment of the present invention, since the hydraulic brake system as described above is provided, the same advantages as described above are obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] 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.

[0033] Figure 1 is a schematic diagram of a hydraulic brake system provided by one embodiment of the present invention;

[0034] Figure 2 is a schematic diagram of a brake valve assembly provided by one embodiment of the present invention;

[0035] Figure 3 is a schematic diagram of a foot valve provided by one embodiment of the present invention;

[0036] Figure 4 is a schematic diagram of a relay valve provided by one embodiment of the present invention;

[0037] Reference numerals:

[0038] 100: Hydraulic oil tank; 200: Hydraulic oil pump; 300: Brake valve group; 311: Front axle accumulator; 312: Rear axle accumulator; 313: Parking accumulator; 321: First solenoid reversing valve; 322: Second solenoid reversing valve; 323: Third solenoid reversing valve; 330: Shuttle valve; 340: Logic valve; 400: Foot valve; 410: Front axle control valve body; 420: Rear axle control valve body; 510: Front axle relay valve; 520: Front axle brake; 610: Rear axle relay valve; 620: Rear axle brake; 700: Parking brake assembly; 800: Quick-plug interface; 900: Controller. DETAILED DESCRIPTION

[0039] 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.

[0040] The following combination Figures 1 to 4 A hydraulic brake system provided by an embodiment of the present invention is described.

[0041] An embodiment of the present invention provides a hydraulic brake system, including an oil supply device, n service brake assemblies, and a foot valve 400 .

[0042] Wherein, n is an integer greater than or equal to 2, that is, in the embodiment provided by the present invention, the number of service brake assemblies is greater than or equal to two groups, and the number of service brake assemblies is not specifically limited.

[0043] At least one service brake assembly includes a relay valve and a set of wet brakes, with the relay valve being disposed between the oil supply device and the wet brakes. This embodiment of the present invention uses an example in which n service brake assemblies each include a relay valve and a wet brake. Of course, other embodiments may also include multiple service brake assemblies equipped with dry brakes.

[0044] The relay valve is used to control the connection between the oil supply device and the wet brake. When the relay valve connects the oil supply device and the wet brake, the oil supply device supplies hydraulic oil to the wet brake through the relay valve, switching the wet brake to the braking state. When the relay valve disconnects the oil supply device and the wet brake, the wet brake loses oil pressure and switches to the released state.

[0045] The foot valve 400 is provided between the oil supply device and the control end of the relay valve. The foot valve 400 is used to control the on-off between the oil supply device and the control end of the relay valve, thereby controlling the relay valve to connect or disconnect the connection between the oil supply device and the wet brake.

[0046] When the foot valve 400 connects the oil supply device and the control end of the relay valve, the oil supply device supplies hydraulic oil to the control end of the relay valve, the control end of the relay valve establishes oil pressure, and controls the relay valve to connect the oil supply device and the wet brake, so that the wet brake enters the braking state.

[0047] When the foot valve 400 cuts off the connection between the oil supply device and the control end of the relay valve, the hydraulic oil of the oil supply device cannot be supplied to the control end of the relay valve, and the oil pressure at the control end of the relay valve cannot be maintained, causing the relay valve to cut off the connection between the oil supply device and the wet brake, causing the wet brake to enter a brake-released state.

[0048] Among them, the foot valve 400 can simultaneously control the connection between the control ends of n relay valves and the oil supply device. When the foot valve 400 is switched to the first working position, the foot valve 400 simultaneously connects the connection between the oil supply device and the control ends of n relay valves. When the foot valve 400 is switched to the second working position, the foot valve 400 simultaneously cuts off the connection between the oil supply device and the control ends of n relay valves.

[0049] Furthermore, when the foot valve 400 is in the first working position, the n relay valves are all in the third working position, at which point the n relay valves connect the oil supply device to the n wet brakes. When the foot valve 400 is in the second working position, the relay valves are in the fourth working position, at which point the n relay valves disconnect the oil supply device from the n wet brakes.

[0050] The hydraulic braking system provided by this invention utilizes a wet brake. Both dry and wet brakes utilize friction to dissipate mechanical kinetic energy into heat. However, wet brakes utilize a closed structure, with the friction pads operating in an oil-immersed, enclosed environment. While some of the heat generated during braking is absorbed by the brake's structural components, the majority is carried away by the coolant, facilitating heat dissipation. Because wet brakes are resistant to high temperatures, exhibit excellent heat dissipation, and exhibit minimal wear, they offer enhanced thermal and braking stability, significantly enhancing the safety of construction machinery during operation and operation.

[0051] Moreover, the hydraulic braking system provided by the embodiment of the present invention controls the switching of the relay valve through the foot valve 400, so that the relay valve can open or cut off the connection between the oil supply device and the wet brake. When the relay valve connects the oil supply device and the wet brake, sufficient hydraulic oil can be provided to the actuator through the relay valve, thereby solving the problem of insufficient hydraulic oil flow caused by direct oil supply through the foot valve 400 in the related art.

[0052] In some embodiments of the present invention, the oil supply device may include an oil supply assembly and a brake valve assembly 300. The oil supply assembly includes a hydraulic oil pump 200 and a hydraulic oil tank 100. The brake valve assembly 300 is used to control the oil supply from the oil supply assembly to the n service brake assemblies.

[0053] The foot valve 400 may include a front axle control valve body 410 and a rear axle control valve body 420, and the front axle control valve body 410 and the rear axle control valve body 420 are controlled by a control end, which can control the front axle control valve body 410 and the rear axle control valve body 420 to switch working states at the same time.

[0054] The front axle control valve body 410 and the rear axle control valve body 420 each include a fourth oil inlet port P4 , a fourth working oil port A4 , and a third oil return port T3 .

[0055] The brake valve assembly 300 includes a first oil inlet P1 and n first operating oil ports A1. The suction port of the hydraulic oil pump 200 is connected to the hydraulic oil tank 100, and the discharge port of the hydraulic oil pump 200 is connected to the first oil inlet P1 of the brake valve assembly 300, supplying hydraulic oil to the brake valve assembly 300. The brake valve assembly 300 then distributes the hydraulic oil. The n first operating oil ports A1 are respectively connected to the n fourth oil inlets P4 of the foot valve 400 and the third oil inlets P3 of the n relay valves.

[0056] The n first working oil ports A1 of the brake valve group 300 are connected to the first oil inlet P1 in real time, the first working oil port A1 is connected to the corresponding fourth oil inlet P4 on the foot valve 400 in real time, the first working oil port A1 is connected to the third oil inlet P3 of the relay valve in real time, and the fourth working oil port A4 of the foot valve 400 is connected to the corresponding fourth pilot oil port PP4 of the relay valve in real time.

[0057] When the foot valve 400 is in the first working position, the fourth oil inlet P4 of the foot valve 400 is connected to the corresponding fourth working oil port A4, and the oil supply device delivers the hydraulic oil to the fourth pilot oil port PP4 of the relay valve through the brake valve group 300 and the foot valve 400. The relay valve switches to the third working position, and the third oil inlet P3 of the relay valve is connected to the third working oil port A3. When the foot valve 400 is in the second working position, the foot valve 400 cuts off the connection between the fourth oil inlet P4 and the fourth working oil port A4, and cuts off the connection between the first working oil port A1 of the brake valve group 300 and the fourth pilot oil port PP4 of the relay valve. At this time, the fourth working oil port A4 of the foot valve 400 is connected to the third return oil port T3 of the foot valve 400, and the hydraulic oil in the fourth pilot oil port PP4 of the relay valve flows to the third return oil port T3 through the fourth working oil port A4 of the foot valve 400, and finally flows back to the hydraulic oil tank 100. The fourth pilot oil port PP4 of the relay valve is depressurized, and the relay valve is switched to the fourth working position. The third oil inlet P3 and the third working oil port A3 of the relay valve are disconnected, and the third working oil port A3 of the relay valve is connected to the second return oil port T2 of the relay valve.

[0058] When the relay valve works in the third working position, the third oil inlet P3 and the third working oil port A3 of the relay valve are connected, and the oil supply device transports the hydraulic oil to the corresponding wet brake through the first working oil port A1 of the brake valve group 300, the third oil inlet P3 and the third working oil port A3 of the relay valve, so that the wet brake switches to the braking state.

[0059] When the relay valve works in the fourth working position, the third oil inlet P3 of the relay valve is disconnected from the third working oil port A3, and the third working oil port A3 of the relay valve is connected to the second oil return port T2. The hydraulic oil in the wet brake flows back to the hydraulic oil tank 100 through the third working oil port A3 and the second oil return port T2 of the relay valve, and the wet brake is depressurized to release the brake.

[0060] In some embodiments of the present invention, the brake valve group 300 also includes a first solenoid reversing valve 321, and a first pilot oil port PP1 is also provided on the brake valve group 300. The first solenoid reversing valve 321 includes a fifth oil inlet P5, a fifth working oil port A5 and a fifth oil return port T5, and a second pilot oil port PP2 is provided on the foot valve 400.

[0061] The fifth oil inlet P5 of the first solenoid reversing valve 321 is connected to the first oil inlet P1 of the brake valve group 300, the fifth working oil port A5 of the first solenoid reversing valve 321 is connected to the first pilot oil port PP1 of the brake valve group 300, the fifth oil return port T5 of the first solenoid reversing valve 321 is connected to the first oil return port T1 of the brake valve group 300, and the first pilot oil port PP1 of the brake valve group 300 is connected to the second pilot oil port PP2 of the foot valve 400.

[0062] During operation, when the first solenoid reversing valve 321 switches to the fifth operating position, the fifth oil inlet P5 of the first solenoid reversing valve 321 connects to the fifth operating oil port A5. Hydraulic oil from the oil supply device flows through the first oil inlet P1, the fifth oil inlet P5, the fifth operating oil port A5, and the first pilot oil port PP1 to the second pilot oil port PP2 of the foot valve 400. Oil pressure is established at the second pilot oil port PP2 of the foot valve 400, and the foot valve 400 switches to the first operating position.

[0063] When the first solenoid reversing valve 321 switches to the sixth working position, the fifth oil inlet P5 of the first solenoid reversing valve 321 is disconnected from the fifth working oil port A5. The fifth working oil port A5 of the first solenoid reversing valve 321 is connected to the fifth oil return port T5. The hydraulic oil supplied by the oil supply device to the first pilot oil port PP1 is blocked by the first solenoid reversing valve 321. The hydraulic oil at the second pilot oil port PP2 of the foot valve 400 flows back through the fifth working oil port A5 and the fifth oil return port T5 of the first solenoid reversing valve 321 to the first oil return port T1 of the brake valve assembly 300, and finally back to the hydraulic oil tank 100. The oil pressure at the second pilot oil port PP2 of the foot valve 400 is lost, and the foot valve 400 switches to the second working position.

[0064] In other embodiments of the present invention, a manual control end can also be provided on the foot valve 400, and a valve stem is provided inside the foot valve 400. The manual control end can be a foot pedal. When the foot pedal is stepped on, the foot valve 400 can be switched to the first working position through the valve stem. When the foot pedal is released, the foot pedal automatically returns to its position and drives the foot valve 400 to switch to the second working position through the valve stem.

[0065] In some embodiments of the present invention, the brake valve assembly 300 further includes m second solenoid reversing valves 322, and the brake valve assembly 300 is provided with m third pilot oil ports PP3. Each second solenoid reversing valve 322 includes a sixth oil inlet P6, a sixth operating oil port A6, and a sixth oil return port T6. The sixth oil inlet P6 of the m second solenoid reversing valves 322 is connected to the first oil inlet P1 of the brake valve assembly 300. The sixth operating oil ports A6 of the m second solenoid reversing valves 322 are connected in a one-to-one correspondence with the m third pilot oil ports PP3 of the brake valve assembly 300. The sixth oil return ports T6 of the m second solenoid reversing valves 322 are connected to the first oil return port T1 of the brake valve assembly 300. The m third pilot oil ports PP3 of the brake valve assembly 300 are connected to the fourth pilot oil ports PP4 of the m relay valves. Here, m ≥ 1 and m ≤ n.

[0066] During operation, when one of the second solenoid reversing valves 322 is switched to the seventh working position, the sixth oil inlet P6 of the second solenoid reversing valve 322 is connected to the sixth working oil port A6, and the oil supply device supplies oil to the fourth pilot oil port PP4 of the corresponding relay valve through the first oil inlet P1 of the brake valve group 300, the sixth oil inlet P6 of the second solenoid reversing valve 322, the sixth working oil port A6 of the second solenoid reversing valve 322 and the third pilot oil port PP3 of the brake valve group 300, and the relay valve is switched to the third working position.

[0067] When one of the second solenoid reversing valves 322 is switched to the eighth working position, the connection between the sixth oil inlet port P6 of the second solenoid reversing valve 322 and the sixth working oil port A6 is cut off, and the sixth working oil port A6 of the second solenoid reversing valve 322 is connected to the sixth oil return port T6 of the second solenoid reversing valve 322. The hydraulic oil supplied by the oil supply device to the fourth pilot oil port PP4 of the relay valve is blocked, and the hydraulic oil in the fourth pilot oil port PP4 of the relay valve enters the sixth oil return port T6 of the second solenoid reversing valve 322 through the sixth working oil port A6 of the second solenoid reversing valve 322, and finally flows to the hydraulic oil tank 100 through the first oil return port T1 of the brake valve body. The fourth pilot oil port PP4 of the relay valve is depressurized, and the relay valve is switched to the fourth working position.

[0068] Without the control of the second solenoid reversing valve 322, the foot valve 400 would control n relay valves to switch simultaneously to the third or fourth working position. However, in this embodiment, each second solenoid reversing valve 322 can independently control the operating state of a relay valve. In actual operation, one or more second solenoid reversing valves 322 can be selectively controlled to switch to the seventh or eighth working position. By bypassing the foot valve 400 and directly controlling the relay valves, one, two, or more relay valves can be individually controlled to switch between the third and fourth working positions, allowing one, two, or more service brake assemblies to apply or release the brakes.

[0069] In some embodiments of the present invention, the brake valve group 300 further includes m shuttle valves 330 , and the brake valve group 300 is further provided with m second oil inlets P2 .

[0070] Each shuttle valve 330 includes a ninth oil inlet, a tenth oil inlet, and an output oil port. The ninth oil inlets of the m shuttle valves 330 are connected to the sixth operating oil ports A6 of the m second solenoid reversing valves 322, the tenth oil inlets of the m shuttle valves 330 are connected to the m second oil inlets P2 in a one-to-one correspondence, the output oil ports of the m shuttle valves 330 are connected to the m third pilot oil ports PP3, and the m second oil inlets P2 of the brake valve assembly 300 are connected to the fourth operating oil port A4 of the foot valve 400 in a one-to-one correspondence.

[0071] When the oil pressure of the ninth oil inlet is greater than the oil pressure of the tenth oil inlet, the output oil port outputs the hydraulic oil introduced into the ninth oil inlet; otherwise, the output oil port outputs the hydraulic oil introduced into the tenth oil inlet.

[0072] During operation, the foot valve 400 can be selectively switched to the first working position, causing the second solenoid reversing valve 322 to switch to the eighth working position. The sixth oil inlet P6 and the sixth operating oil port A6 of the second solenoid reversing valve 322 are shut off. At this point, the oil supply device delivers hydraulic oil to the second oil inlet P2 of the brake valve assembly 300 via the foot valve 400, establishing oil pressure at the corresponding tenth oil inlet of the shuttle valve 330. The hydraulic oil supplied by the oil supply device to the corresponding ninth oil inlet of the shuttle valve 330 is blocked by the second solenoid reversing valve 322, resulting in no oil pressure at the ninth oil inlet. The output port of the shuttle valve 330 then delivers hydraulic oil from the tenth oil inlet, and the operation of the corresponding service brake assembly is controlled by the foot valve 400.

[0073] Alternatively, the foot valve 400 can be selectively switched to the second operating position, causing the second solenoid reversing valve 322 to switch to the seventh operating position. At this point, the hydraulic oil supplied by the oil supply device to the second oil inlet P2 is blocked by the foot valve 400, and the corresponding tenth oil inlet of the shuttle valve 330 is deactivated. The oil supply device then delivers hydraulic oil to the corresponding ninth oil inlet of the shuttle valve 330 via the second solenoid reversing valve 322. Oil pressure builds up at the ninth oil inlet, and the output port of the shuttle valve 330 then outputs the hydraulic oil from the ninth oil inlet. At this point, the operation of the corresponding service brake assembly is controlled by the second solenoid reversing valve 322.

[0074] In some embodiments of the present invention, a parking brake assembly 700 is further included, the brake valve group 300 further includes a third electromagnetic reversing valve 323 , and the brake valve group 300 is further provided with a second working oil port A2 .

[0075] The third solenoid reversing valve 323 includes a seventh oil inlet P7, a seventh working oil port A7 and a seventh oil return port T7. The seventh oil inlet P7 is connected to the first oil inlet P1 of the brake valve group 300, the seventh working oil port A7 is connected to the second working oil port A2 of the brake valve group 300, the second working oil port A2 of the brake valve group 300 is connected to the parking brake assembly 700, and the seventh oil return port T7 is connected to the first oil return port T1 of the brake valve group 300.

[0076] During operation, the third solenoid reversing valve 323 can be controlled to switch to the ninth working position. At this time, the connection between the seventh oil inlet P7 of the third solenoid reversing valve 323 and the seventh working oil port A7 is cut off, and the seventh working oil port A7 of the third solenoid reversing valve 323 is connected to the seventh return oil port T7. The hydraulic oil in the parking brake assembly 700 flows back to the first return oil port T1 of the brake valve group 300 through the second working oil port A2 of the brake valve group 300, the seventh working oil port A7 of the third solenoid reversing valve 323 and the seventh return oil port T7 of the third solenoid reversing valve 323, and finally the hydraulic oil returns to the hydraulic oil tank 100. At this time, the parking brake assembly 700 loses oil pressure and switches to the parking brake state.

[0077] Alternatively, the third solenoid reversing valve 323 can be switched to the tenth operating position, where the seventh oil inlet P7 of the third solenoid reversing valve 323 is connected to the seventh operating oil port A7. Hydraulic oil from the oil supply device enters the parking brake assembly 700 through the first oil inlet P1 of the brake valve block 300, the seventh oil inlet P7 of the third solenoid reversing valve 323, the seventh operating oil port A7 of the third solenoid reversing valve 323, and the second operating oil port A2 of the brake valve block 300. The parking brake assembly 700 is released under the action of the hydraulic oil.

[0078] In some embodiments of the present invention, a quick-connect interface 800 may be provided between the second working oil port A2 of the brake valve assembly 300 and the parking brake assembly 700 , and the quick-connect interface 800 may be connected to an external hydraulic oil source.

[0079] In this way, when the oil supply device of the hydraulic brake system fails and cannot supply oil to the parking brake assembly 700, an external hydraulic oil source can be connected through the quick-connect interface 800 to supply oil to the parking brake assembly 700, so that the parking brake assembly 700 releases the brake.

[0080] In some embodiments of the present invention, an accumulator is connected to the channel between each first working oil port A1 and the first oil inlet P1. The accumulator is used to balance the system oil pressure. When the amount of hydraulic oil supplied by the oil supply component decreases, the accumulator is used to replenish the oil. When the amount of hydraulic oil supplied by the oil supply component is high, the accumulator is filled with oil.

[0081] Each accumulator is connected to the first oil return port T1 of the brake valve group 300 through a logic valve 340. The logic valve 340 includes an eighth oil inlet port P8, an eighth working oil port A8 and a fifth pilot oil port PP5.

[0082] The eighth oil inlet P8 of the logic valve 340 is connected to the corresponding accumulator, the eighth working oil port A8 of the logic valve 340 is connected to the first oil return port T1, and the fifth pilot oil port PP5 of the logic valve 340 is connected to the first oil inlet P1.

[0083] When the hydraulic brake system is operating, hydraulic oil from the first oil inlet P1 flows to the fifth pilot oil port PP5 of the logic valve 340. The logic valve 340 is in its eleventh operating position, disconnecting the corresponding accumulator from the first oil return port T1, allowing the accumulator to operate normally. When the hydraulic brake system is shut down, there is no oil pressure in the first oil inlet P1, and consequently, no oil pressure in the fifth pilot oil port PP5 of the logic valve 340. The logic valve 340 switches to its twelfth operating position, connecting the corresponding accumulator to the first oil return port T1, and automatically releasing pressure from the accumulator, achieving automatic pressure relief during shutdown.

[0084] In one embodiment of the present invention, the hydraulic braking system also includes a controller 900, which is electrically connected to the first solenoid reversing valve 321, the second solenoid reversing valve 322 and the third solenoid reversing valve 323, and is used to control the working status of the first solenoid reversing valve 321, the second solenoid reversing valve 322 and the third solenoid reversing valve 323.

[0085] The following will disclose some specific embodiments in conjunction with a specific scenario to illustrate the various working modes of the hydraulic brake system.

[0086] In this scenario, the hydraulic brake system provided by the embodiment of the present invention is applied to the chassis of a 4×2 (4×2 refers to four wheel sets, including two drive wheel sets) engineering machinery, which includes a set of front axles and a set of rear axles.

[0087] In this scenario, the hydraulic brake system includes a hydraulic oil tank 100 , a hydraulic oil pump 200 , a brake valve group 300 , a set of front axle brake assemblies, a set of rear axle brake assemblies, and a foot valve 400 .

[0088] The front axle brake assembly includes a front axle relay valve 510 and a front axle brake 520 , and the rear axle brake assembly includes a rear axle relay valve 610 and a rear axle brake 620 . Both the front axle brake 520 and the rear axle brake 620 are wet brakes.

[0089] The foot valve 400 may include a front axle control valve body 410 and a rear axle control valve body 420, and the front axle control valve body 410 and the rear axle control valve body 420 are controlled by a control end, which can control the front axle control valve body 410 and the rear axle control valve body 420 to switch working states at the same time.

[0090] The front axle control valve body 410 and the rear axle control valve body 420 each include a fourth oil inlet port P4 , a fourth working oil port A4 and a third oil return port T3 . The control end of the foot valve 400 is provided with a second pilot oil port PP2 .

[0091] The brake valve assembly 300 includes a first oil inlet port P1, two first operating oil ports A1, a second operating oil port A2, a first pilot oil port PP1, a third pilot oil port PP3, and a first oil return port T1. The brake valve assembly 300 also includes a first solenoid reversing valve 321, a second solenoid reversing valve 322, and a third solenoid reversing valve 323.

[0092] Among them, the first oil inlet P1 is used to connect with the oil outlet end of the hydraulic oil pump 200, one first working oil port A1 is connected with the third oil inlet P3 of the front axle relay valve 510 and the fourth oil inlet P4 of the front axle control valve body 410 of the foot valve 400, and another first working oil port A1 is connected with the third oil inlet P3 of the rear axle relay valve 610 and the fourth oil inlet P4 of the rear axle control valve body 420 of the foot valve 400.

[0093] The fourth hydraulic oil port A4 of the front axle control valve body 410 of the foot valve 400 is connected to the fourth pilot oil port PP4 of the front axle relay valve 510. The fourth hydraulic oil port A4 of the rear axle control valve body 420 of the foot valve 400 is connected to the fourth pilot oil port PP4 of the rear axle relay valve 610. The second oil return port T2 of the front axle control valve body 410 and the rear axle control valve body 420 of the foot valve 400 is connected to the hydraulic oil tank 100.

[0094] The fifth oil inlet P5 of the first solenoid reversing valve 321 is connected to the first oil inlet P1 of the brake valve group 300, the fifth working oil port A5 of the first solenoid reversing valve 321 is connected to the first pilot oil port PP1 of the brake valve group 300, the fifth oil return port T5 of the first solenoid reversing valve 321 is connected to the first oil return port T1 of the brake valve group 300, and the first pilot oil port PP1 of the brake valve group 300 is connected to the second pilot oil port PP2 of the foot valve 400.

[0095] The sixth oil inlet P6 of the second solenoid reversing valve 322 is connected to the first oil inlet P1 of the brake valve group 300, the sixth working oil port A6 of the second solenoid reversing valve 322 is connected to the ninth oil inlet of the shuttle valve 330, and the sixth oil return port T6 of the second solenoid reversing valve 322 is connected to the first oil return port T1 of the brake valve group 300.

[0096] Since only one second solenoid reversing valve 322 is provided, a corresponding shuttle valve 330 is also provided. The tenth oil inlet of the shuttle valve 330 is connected to the second oil inlet P2 of the brake valve assembly 300, which is in turn connected to the fourth working oil port A4 of the rear axle control valve body 420 of the foot valve 400. The output oil port of the shuttle valve 330 is connected to the third pilot oil port PP3 of the brake valve assembly 300, which is in turn connected to the fourth pilot oil port PP4 of the rear axle relay valve 610.

[0097] There are three accumulators: a front axle accumulator 311, a rear axle accumulator 312, and a parking accumulator 313. The front axle accumulator 311 is connected to the passage between the first hydraulic port A1 connected to the front axle relay valve 510 and the first oil inlet P1. The rear axle accumulator 312 is connected to the passage between the first hydraulic port A1 connected to the rear axle relay valve 610 and the first oil inlet P1. The parking accumulator 313 is connected to the passage between the second hydraulic port A2 and the first oil inlet P1.

[0098] First, release the parking

[0099] The controller 900 receives the parking release instruction and outputs a corresponding control signal to control the third solenoid reversing valve 323 to be electrically reversed, and the third solenoid reversing valve 323 is switched to the tenth working position. The hydraulic oil pump 200 delivers the hydraulic oil through the first oil inlet P1 of the brake valve group 300, the seventh oil inlet P7 of the third solenoid reversing valve 323, the seventh working oil port A7 of the third solenoid reversing valve 323, the second working oil port A2 of the brake valve group 300 and the quick-plug interface 800 to the parking brake assembly 700, so that the parking brake assembly 700 can release the parking.

[0100] Second, parking brake

[0101] The controller 900 receives the parking brake command and outputs a corresponding control signal to control the third solenoid reversing valve 323 to lose power and reverse (shown in the figure). The third solenoid reversing valve 323 switches to the ninth working position. The hydraulic oil in the parking brake assembly 700 flows back to the hydraulic oil tank 100 through the quick-connect connector, the second working oil port A2 of the brake valve group 300, the seventh working oil port A7 of the third solenoid reversing valve 323, the seventh return oil port T7 of the third solenoid reversing valve 323, and the first return oil port T1 of the brake valve group 300 under the action of the internal mechanical force of the parking brake assembly 700. The parking brake assembly 700 is depressurized, and parking braking is achieved under the action of the internal mechanical force of the parking brake assembly 700.

[0102] Third, loading brake

[0103] The controller 900 receives the load brake command and outputs a corresponding control signal, energizing and reversing the second solenoid reversing valve 322. This connects the sixth oil inlet P6 and the sixth working oil port A6 of the second solenoid reversing valve 322. Hydraulic oil output from the hydraulic oil pump 200, the rear axle accumulator 312, and the parking accumulator 313 passes through the second solenoid reversing valve 322 and enters the ninth oil inlet of the shuttle valve 330. Because there is no oil pressure at the tenth oil inlet of the shuttle valve 330, the shuttle valve 330 outputs hydraulic oil from the ninth oil inlet to the third pilot oil port PP3. Hydraulic oil then flows from the third pilot oil port PP3 of the brake valve assembly 300, acting on the fourth pilot oil port PP4 of the rear axle relay valve 610, placing the rear axle relay valve 610 in the left position.

[0104] At this time, the third oil inlet P3 and the third working oil port A3 of the rear axle relay valve 610 are connected, so that the high-flow hydraulic oil output by the hydraulic oil pump 200, the rear axle accumulator 312 and the parking accumulator 313 acts on the rear axle brake 620 to achieve loading braking.

[0105] Fourth, emergency braking

[0106] Under hazardous working conditions, this braking system has an emergency braking function, that is, the front axle brake components and the rear axle brake components brake at the same time.

[0107] The controller 900 receives the emergency braking command and outputs corresponding control signals, causing the first solenoid reversing valve 321 to switch direction when energized and the second solenoid reversing valve 322 to switch direction when de-energized (as shown). At this point, the fifth oil inlet P5 of the first solenoid reversing valve 321 is connected to the fifth working oil port A5, while the sixth oil inlet P6 of the second solenoid reversing valve 322 is disconnected from the sixth working oil port A6. Hydraulic oil output from the hydraulic oil pump 200, the front axle accumulator 311, and the parking accumulator 313 passes through the first solenoid reversing valve 321 and reaches the first pilot oil port PP1 of the brake valve assembly 300. The hydraulic oil then acts on the second pilot oil port PP2 of the foot valve 400 through the first pilot oil port PP1, causing the valve spool of the foot valve 400 to switch direction. At this time, the fourth oil inlet P4 and the fourth working oil port A4 of the front axle control valve body 410 of the foot valve 400 are connected, and the fourth oil inlet P4 and the fourth working oil port A4 of the rear axle control valve body 420 of the foot valve 400 are connected.

[0108] Hydraulic oil from the hydraulic oil pump 200, the front axle accumulator 311, and the parking accumulator 313 flows through the brake valve block 300 and the front axle control valve body 410 of the foot valve 400 to the fourth pilot oil port PP4 of the front axle relay valve 510. The front axle relay valve 510 switches to its third operating position, connecting its third oil inlet port P3 and third operating oil port A3. Hydraulic oil from the hydraulic oil pump 200, the front axle accumulator 311, and the parking accumulator 313 flows through the brake valve block 300 and the front axle relay valve 510 to the front axle brake 520, putting the front axle brake 520 into a braking state.

[0109] Hydraulic oil from the hydraulic oil pump 200, the rear axle accumulator 312, and the parking accumulator 313 flows through the brake valve group 300 and the rear axle control valve body 420 of the foot valve 400 into the second oil inlet P2 of the brake valve group 300, and then into the tenth oil inlet of the shuttle valve 330. Since the second solenoid reversing valve 322 connected to the shuttle valve 330 is de-energized, there is no oil pressure at the ninth oil inlet of the shuttle valve 330. The output port of the shuttle valve 330 then outputs hydraulic oil from the tenth oil inlet. This hydraulic oil then flows through the third pilot oil port PP3 of the brake valve group 300 and acts on the fourth pilot oil port PP4 of the rear axle relay valve 610. The rear axle relay valve 610 switches to its third operating position, connecting its third oil inlet P3 and third operating oil port A3. The hydraulic oil from the hydraulic oil pump 200 , the rear axle accumulator 312 and the parking accumulator 313 enters the rear axle brake 620 through the brake valve group 300 and the rear axle relay valve 610 , and the rear axle brake 620 enters a braking state.

[0110] Fifth, service brake

[0111] During driving, the first solenoid reversing valve 321 and the second solenoid reversing valve 322 are both in a power-off state. At this time, the driver steps on the pedal of the foot valve 400, and the valve core of the foot valve 400 is reversed. At this time, the fourth oil inlet P4 and the fourth working oil port A4 of the front axle control valve body 410 of the foot valve 400 are connected, and the fourth oil inlet P4 and the fourth working oil port A4 of the rear axle control valve body 420 of the foot valve 400 are connected.

[0112] Hydraulic oil from the hydraulic oil pump 200, the front axle accumulator 311, and the parking accumulator 313 flows through the brake valve block 300 and the front axle control valve body 410 of the foot valve 400 to the fourth pilot oil port PP4 of the front axle relay valve 510. The front axle relay valve 510 switches to its third operating position, connecting its third oil inlet port P3 and third operating oil port A3. Hydraulic oil from the hydraulic oil pump 200, the front axle accumulator 311, and the parking accumulator 313 flows through the brake valve block 300 and the front axle relay valve 510 to the front axle brake 520, putting the front axle brake 520 into a braking state.

[0113] Hydraulic oil from the hydraulic oil pump 200, the rear axle accumulator 312, and the parking accumulator 313 flows through the brake valve group 300 and the rear axle control valve body 420 of the foot valve 400 into the second oil inlet P2 of the brake valve group 300, and then into the tenth oil inlet of the shuttle valve 330. Since the second solenoid reversing valve 322 connected to the shuttle valve 330 is de-energized, there is no oil pressure at the ninth oil inlet of the shuttle valve 330. The output port of the shuttle valve 330 then outputs hydraulic oil from the tenth oil inlet. This hydraulic oil then flows through the third pilot oil port PP3 of the brake valve group 300 and acts on the fourth pilot oil port PP4 of the rear axle relay valve 610. The rear axle relay valve 610 switches to its third operating position, connecting its third oil inlet P3 and third operating oil port A3. The hydraulic oil from the hydraulic oil pump 200 , the rear axle accumulator 312 and the parking accumulator 313 enters the rear axle brake 620 through the brake valve group 300 and the rear axle relay valve 610 , and the rear axle brake 620 enters a braking state.

[0114] Sixth, automatic pressure relief of shutdown accumulator

[0115] In the shutdown state, the hydraulic oil pump 200 does not output hydraulic oil, the fifth pilot oil port PP5 of the logic valve 340 has no oil pressure, and the valve core of the logic valve 340 is in the right connection position under the action of the spring force.

[0116] The hydraulic oil in the front axle accumulator 311 , the rear axle accumulator 312 and the parking accumulator 313 returns to the hydraulic oil tank 100 through the corresponding logic valve 340 and the first oil return port T1 of the brake valve group 300 , completing the pressure relief.

[0117] 7. Emergency release of parking brake

[0118] When the oil supply device of the hydraulic brake system fails and cannot provide hydraulic oil, the quick-connect interface 800 can be used to connect to an external power source such as a hand pump or a rescue vehicle to quickly release the parking brake and supply it for use in emergency towing.

[0119] Of course, on other types of construction machinery chassis, the number of service brake assemblies is not limited to two. For example, the chassis may include one front axle brake assembly and two rear axle brake assemblies, in which case n = 3; or the chassis may include two front axle brake assemblies and two rear axle brake assemblies, in which case n = 4. The operating principle is the same as that of the 4×2 chassis described above, differing only in the number of service brake assemblies.

[0120] An embodiment of the present invention further provides an engineering machine, which may be a mining dump truck, an excavator, a crane, etc. Since they are all provided with the hydraulic braking system as described above, they have the same advantages as described above and are not described in detail here.

[0121] 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 hydraulic brake system, characterized in that: include: Oil supply device; n service brake assemblies, at least one of the service brake assemblies comprising a relay valve and a wet brake, wherein the relay valve is disposed between the oil supply device and the wet brake; A foot valve (400), the foot valve (400) being arranged between the oil supply device and the control end of the relay valve; When the foot valve (400) connects the oil supply device and the control end of the relay valve, the relay valve connects the oil supply device and the wet brake, and the wet brake is in a braking state; Where n≥2; The oil supply device comprises: Oil supply components; A brake valve assembly (300), the brake valve assembly (300) comprising a first oil inlet P1 and n first working oil ports A1; The oil supply assembly is connected to the first oil inlet P1, the n relay valves are arranged one-to-one between the n first working oil ports A1 and the n wet brakes, and the foot valve (400) is arranged between the n first working oil ports A1 and the control ends of the n relay valves; The brake valve assembly (300) includes a first electromagnetic reversing valve (321), and a first pilot oil port PP1 is provided on the brake valve assembly (300), and the first electromagnetic reversing valve (321) is provided between the first oil inlet port P1 and the first pilot oil port PP1; The foot valve (400) is provided with a second pilot oil port PP2, and the second pilot oil port PP2 is communicated with the first pilot oil port PP1; When the first electromagnetic reversing valve (321) connects the first oil inlet P1 and the first pilot oil port PP1, the second pilot oil port PP2 establishes oil pressure, and the foot valve (400) connects the first working oil port A1 and the corresponding control end of the relay valve; The brake valve group (300) further includes m second electromagnetic reversing valves (322), and the brake valve group (300) is further provided with m third pilot oil ports PP3, the m third pilot oil ports PP3 being connected to the control ends of the m relay valves in a one-to-one correspondence, the m second electromagnetic reversing valves (322) being provided between the first oil inlet P1 and the m third pilot oil ports PP3 in a one-to-one correspondence, and the second electromagnetic reversing valves (322) being used to control the opening and closing of the corresponding third pilot oil ports PP3 and the first oil inlet P1; When the second electromagnetic reversing valve (322) connects the corresponding third pilot oil port PP3 to the first oil inlet port P1, the corresponding relay valve connects the corresponding first working oil port A1 to the corresponding wet brake; Where m≥1 and m≤n.

2. The hydraulic brake system according to claim 1, characterized in that: The foot valve (400) further comprises a manual control end, and the manual control end is used to control the foot valve (400) to connect or disconnect the first working oil port A1 from the corresponding control end of the relay valve.

3. The hydraulic brake system according to claim 1, characterized in that: The brake valve group (300) further includes m shuttle valves (330), and the brake valve group (300) is further provided with m second oil inlets P2. The ninth oil inlet of the shuttle valve (330) is communicated with the corresponding second solenoid reversing valve (322), the tenth oil inlet of the shuttle valve (330) is communicated with the corresponding second oil inlet P2, the output oil port of the shuttle valve (330) is communicated with the corresponding third pilot oil port PP3, and the m first working oil ports A1 are connected to the m second oil inlets P2 in a one-to-one correspondence through the foot valve (400).

4. The hydraulic brake system according to claim 1, characterized in that: The invention also includes a parking brake assembly (700), the brake valve group (300) further includes a third electromagnetic reversing valve (323), the brake valve group (300) is further provided with a second working oil port A2 and a first oil return port T1, the third electromagnetic reversing valve (323) is arranged between the first oil inlet P1, the second working oil port A2 and the first oil return port T1, the second working oil port A2 is connected to the parking brake assembly (700), and the third electromagnetic reversing valve (323) is used to selectively connect the second working oil port A2 with the first oil inlet P1 or the first oil return port T1.

5. The hydraulic brake system according to claim 4, characterized in that: A quick-connect interface (800) for connecting to an external oil source is also provided between the second working oil port A2 and the parking brake assembly (700).

6. The hydraulic brake system according to claim 4, characterized in that: An accumulator is connected to the channel between each of the first working oil ports A1 and the first oil inlet port P1; Each accumulator is connected to the first oil return port T1 via a logic valve (340). The control end of the logic valve (340) is connected to the first oil inlet P1. When there is oil pressure at the control end of the logic valve (340), the logic valve (340) cuts off the connection between the corresponding accumulator and the first oil return port T1. When there is no oil pressure at the control end of the logic valve (340), the logic valve (340) connects the corresponding accumulator to the first oil return port T1.

7. An engineering machine, characterized in that: The invention comprises a hydraulic brake system as claimed in any one of claims 1 to 6.

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