Brake control valve, hydraulic brake system, and work machine

Abstract

The invention belongs to the technical field of operation machinery and provides a brake control valve, a hydraulic brake system and an operation machine.The brake control valve is provided with an oil inlet, an oil return port and a brake working oil port and further provided with a first valve position, a second valve position, a brake control end and a reset end, and the brake control end and the reset end are opposite to the two ends; the first valve position is used for communicating the oil inlet with the brake working oil port, and the second valve position is used for communicating the oil return port with the brake working oil port and the oil inlet; the brake control end is used for controlling the brake control valve to be switched to the first valve position, and the reset end is used for driving the brake control valve to reset to the second valve position. The brake control valve not only is simple in structure, but also can realize synchronization of oil way reversing and pressure proportion self-adaptive adjustment.

Description

Technical Field

[0001] The present invention belongs to the technical field of construction machinery, and particularly relates to a brake control valve, a hydraulic braking system and a construction machinery. Background Art

[0002] In the field of construction machinery, agricultural equipment and other construction machinery, as a core mechanism, the hydraulic braking system directly affects the safety of equipment operation and the operation efficiency with its braking performance. In order to achieve flexible braking (that is, the pressure gradient is adjustable and the impact load is controllable during the braking process) in traditional hydraulic braking systems, a realization scheme of cooperative control of a proportional valve and a reversing valve is generally adopted.

[0003] Specifically, in the prior art, the pressure of the hydraulic circuit is usually linearly adjusted by a proportional valve to achieve a gradual output of the braking force, and at the same time, the reversing valve is relied on to complete the on-off switching and flow direction control of the braking oil circuit. The two valves need to achieve timing matching through a complex linkage control logic. For example, during the braking start stage, it is necessary to accurately control the synchronization of the opening of the proportional valve and the switching action of the reversing valve to avoid mechanical impact caused by pressure mutation. Although this design mode can meet the basic flexible braking requirements, it has obvious defects: First, the dual-valve parallel structure greatly increases the complexity of the hydraulic circuit, resulting in a large space occupied by the system and difficult pipeline layout, especially in compact equipment with limited space, its applicability is poor; Second, the cooperative control of the proportional valve and the reversing valve relies on high-precision sensors and special control algorithms, and has strict requirements for parameters such as signal sampling frequency and valve body response time, significantly increasing the development cost of the control system; Third, during the cooperation of the two valves, it is easy to cause inaccurate action timing due to mechanical wear or oil pollution, resulting in problems such as braking hysteresis or pressure oscillation, seriously affecting the reliability of the system. Summary of the Invention

[0004] In view of the above defects or deficiencies, the present invention provides a brake control valve, a hydraulic braking system and a construction machinery, aiming to solve the technical problems of the existing brake control scheme with complex structure and difficult control.

[0005] To achieve the above object, the present invention provides a brake control valve, which is provided with an oil inlet, an oil return port and a brake working oil port. The brake control valve is further provided with a first valve position, a second valve position, braking control ends at opposite ends and a reset end; the first valve position is used to conduct the oil inlet and the brake working oil port, and the second valve position is used to conduct the oil return port with the brake working oil port and the oil inlet respectively; the braking control end is used to control the brake control valve to switch to the first valve position, and the reset end is used to drive the brake control valve to reset to the second valve position.

[0006] In an embodiment of the present invention, the brake control valve includes a valve body and a control spool. An oil inlet, an oil return port, and a brake working oil port are arranged on the valve body. The control spool is movably arranged in the valve cavity channel of the valve body. The two ends of the valve cavity channel are respectively the brake control end and the reset end of the valve body. A driving structure for driving the control spool to move towards the reset end is arranged on the brake control end. The reset end is provided with a spring and a reset driving oil port that are jointly used to drive the control spool to move towards the brake control end. The reset driving oil port is communicated with the brake working oil port.

[0007] In an embodiment of the present invention, the reset driving oil port and the brake working oil port are communicated through a bypass oil passage on the valve body, and a throttling damping device is arranged in the bypass oil passage.

[0008] In an embodiment of the present invention, an axial end of the control spool close to the reset end is a first driving end. A reset working groove is arranged on the first driving end, and the reset working groove is in alignment and communication with the reset driving oil port on the valve body.

[0009] In an embodiment of the present invention, an axial end of the control spool close to the reset end is a first driving end. A limiting step is further arranged on the first driving end. The spring is sleeved on the first driving end and abuts against the limiting step. The spring is used to push the control spool in the direction of the brake control end.

[0010] In an embodiment of the present invention, a plug is arranged on the reset end of the valve body, and the spring elastically abuts between the plug and the limiting step.

[0011] In an embodiment of the present invention, the driving structure includes a brake control oil port arranged on the brake control end of the valve body. The brake control oil port is used to be externally connected to the brake control oil circuit of the hydraulic system. An axial end of the control spool close to the brake control end is a second driving end. A brake working groove is arranged on the second driving end, and the brake working groove is in alignment and communication with the brake control oil port.

[0012] In an embodiment of the present invention, an axial end of the control spool close to the reset end is a first driving end, and an end close to the brake control end is a second driving end. The diameter of the second driving end is larger than that of the first driving end.

[0013] To achieve the above object, the present invention further provides a hydraulic braking system, wherein the hydraulic braking system includes the brake control valve described above.

[0014] To achieve the above object, the present invention further provides a working machine, wherein the working machine includes the hydraulic braking system described above.

[0015] Through the above technical solutions, the brake control valve provided by the embodiment of the present invention has the following beneficial effects:

[0016] When the driver steps on the brake pedal on the machine or performs other types of braking operations, the brake control end of the brake control valve will have an electrical signal or hydraulic pressure input, thereby driving the brake control valve to switch to the first valve position. After the brake control valve switches to the first valve position, the pressure oil at the oil inlet will flow to the brake working oil port to drive the brake actuator (such as the brake cylinder) to operate. At the same time, the reset force of the reset end will balance the driving force of the brake control end. Through balance, the opening of the brake control valve in the first valve position can be adaptively adjusted, so that the brake control valve has the function of proportionally controlling the pressure output according to the strength of the brake control end input, thereby realizing flexible braking of the machine.

[0017] In summary, the brake control valve in the embodiment of the present invention adopts an integrated design to replace the original parallel layout of the proportional valve and the reversing valve, and integrates the pressure proportional output adjustment, oil circuit on-off switching, and oil circuit flow direction control functions on one valve, completely eliminating the complex pipelines and control modules required for the dual-valve linkage, simplifying the control, and effectively avoiding the pressure step mutation problem caused by the oil circuit switching delay of the traditional split valve group. And when there is no electrical signal or hydraulic pressure input at the brake control end (that is, when the brake operation is not performed), the hydraulic oil at the oil inlet will be depressurized through the oil return port to avoid continuous pressure buildup at the oil inlet. Therefore, when the brake operation is not performed, due to the continuous pressure relief at the oil inlet, when the oil inlet and the brake working oil port are just connected, the sudden pressure change at the brake working oil port can be avoided, thereby ensuring the smooth control of the brake force by the brake control valve.

[0018] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are used to provide an understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention, but do not constitute a limitation of the present invention. In the accompanying drawings:

[0020] Figure 1 is a hydraulic principle diagram of a brake control valve according to an embodiment of the present invention;

[0021] Figure 2 is a specific structural diagram of a brake control valve according to an embodiment of the present invention;

[0022] Figure 3 Detailed structural diagram of the control valve core according to an embodiment of the present invention.

[0023] Description of Reference Numerals

[0024] P, oil inlet; T, oil return port; A, brake working oil port; 1a, first valve position; 1b, second valve position; 11, valve body; 111, brake control end; 111a, brake control oil port; 112, reset end; 112a, reset drive oil port; 113, bypass oil passage; 12, control spool; 121, reset working groove; 122, brake working groove; 123, limiting step; 13, throttle damping device; 14, plug; 15, spring; 16, sealing ring. Detailed implementation manners

[0025] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not used to limit the present invention.

[0026] The brake control valve of the present invention will be described below with reference to the accompanying drawings.

[0027] The present invention provides a brake control valve, as Figure 1 shown. In principle, the brake control valve in the embodiment of the present invention is provided with an oil inlet P, an oil return port T, and a brake working oil port A. The brake control valve is also provided with a first valve position 1a, a second valve position 1b, and brake control ends 111 and a reset end 112 at opposite ends.

[0028] The first valve position 1a is used to conduct the oil inlet P and the brake working oil port A, and the second valve position 1b is used to conduct the oil return port T with the brake working oil port A and the oil inlet P respectively.

[0029] The brake control end 111 is used to control the brake control valve to switch to the first valve position 1a, and the reset end 112 is used to drive the brake control valve to reset to the second valve position 1b.

[0030] When the driver steps on the brake pedal on the machine or performs other types of braking operations, an electrical signal or hydraulic pressure is input to the brake control end 111 of the brake control valve, thereby driving the brake control valve to switch to the first valve position 1a. After the brake control valve switches to the first valve position 1a, the pressure oil at the oil inlet P will flow to the brake working oil port A to drive the brake actuator (such as a brake cylinder) to act. At the same time, the reset force of the reset end 112 will balance the driving force of the brake control end 111. Through this balance, the opening degree of the brake control valve in the first valve position 1a can be adaptively adjusted, so that the brake control valve has the function of proportionally controlling the pressure output according to the strength of the input at the brake control end 111, realizing the flexible braking of the machine.

[0031] In summary, the brake control valve in the embodiment of the present invention adopts an integrated design to replace the original parallel layout of the proportional valve and the reversing valve, and integrates the pressure proportional output adjustment, oil circuit on-off switching, and oil circuit flow direction control functions on one valve, completely eliminating the complex pipelines and control modules required for the dual-valve linkage, simplifying the control, and effectively avoiding the pressure step mutation problem caused by the oil circuit switching delay of the traditional split valve group. And when there is no electrical signal or hydraulic pressure input at the brake control end 111 (that is, when the brake operation is not performed), the hydraulic oil at the oil inlet P will be depressurized through the oil return port T to avoid continuous pressure buildup at the oil inlet P. Therefore, when the brake operation is not performed, due to the continuous depressurization of the oil inlet P, when the oil inlet P and the brake working oil port A are just connected, the brake working oil port A can avoid a sudden pressure change, thereby ensuring the smooth control of the brake force by the brake control valve.

[0032] like Figure 1 As shown, in the embodiment of the present invention, the reset end 112 can be reset only by the spring 15, or by the spring 15 and the hydraulic force, or only by the hydraulic force, or by the electromagnetic force. For example, in addition to the spring 15, the reset end 112 can also be provided with a reset drive oil port 112a connected to the brake working oil port A.

[0033] Since the reset end 112 is connected to the brake working oil port A, part of the pressure oil flowing from the oil inlet P to the brake working oil port A will be diverted to the reset end 112 to balance the driving force of the brake control end 111 together with the spring 15 of the reset end 112. Through the balance, it is further convenient to adaptively control the opening of the brake control valve in the first valve position 1a, thereby controlling the opening amount between the oil inlet P and the brake working oil port A.

[0034] Structurally, if Figure 2 and Figure 3 As shown, the brake control valve in the embodiment of the present invention is a sliding valve and includes a valve body 11 and a control valve core 12. The oil inlet P, the oil return port T, and the brake working oil port A are arranged on the valve body 11. The control valve core 12 is movably arranged in the valve cavity channel of the valve body 11. The two ends of the valve cavity channel are the brake control end 111 and the reset end 112 of the valve body 11 respectively. The brake control end 111 is provided with a driving structure for driving the control valve core 12 to move toward the reset end 112. The reset end 112 is provided with a spring 15 and a reset driving oil port 112a for driving the control valve core 12 to move toward the brake control end 111. The reset driving oil port 112a is connected with the brake working oil port A. Among them, the opening between the oil inlet P and the brake working oil port A increases with the increase of the distance that the control valve core 12 moves toward the reset end 112.

[0035] The braking control end 111 refers to one end in the valve body 11 that is used to receive an external signal or external pilot hydraulic fluid and trigger the movement of the control spool 12. By driving the control spool 12 to move, the fluid passage in the valve body 11 can be changed. Among them, the movement of the control spool 12 can be driven by hydraulic pressure or electromagnetic force, that is, the driving structure on the braking control end 111 can be a driving oil port opened on the valve body 11, or an electromagnet arranged on the valve body 11.

[0036] On the contrary, the other end of the valve body 11 is the reset end 112. Generally, a spring 15 is built in the reset end 112, and a reset driving oil port 112a is also provided at the reset end 112 of the braking control valve in the embodiment of the present invention. The reset of the control spool 12 is jointly driven by the spring 15 and the oil fluid in the reset driving oil port 112a.

[0037] When a braking operation is performed, an electrical signal or hydraulic pressure is input to the braking control end 111, the control spool 12 moves toward the reset end 112, and the braking control valve switches to the first valve position 1a where the oil inlet port P is in communication with the braking working oil port A, and the braking actuator starts to work. At the same time, a part of the pressure oil at the braking working oil port A is diverted to the reset driving oil port 112a at the reset end 112 to jointly balance the driving force of the braking control end 111 with the spring 15, so that the control spool 12 stays at the first balance position. At this time, the oil inlet port P and the braking working oil port A are in a first partial conduction state, and the braking control valve outputs according to the first ratio. When the electrical signal or hydraulic pressure input to the braking control end 111 increases, the control spool 12 continues to move toward the reset end 112, the opening degrees of the oil inlet port P and the braking working oil port A increase, and the pressure input from the braking working oil port A to the reset driving oil port 112a also increases. At this time, the control spool 12 stays at the second balance position, and the oil inlet port P and the braking working oil port A are in a second partial conduction state, and the braking control valve is adaptively adjusted to the second ratio output.

[0038] Since the braking control valve in the embodiment of the present invention integrates functions of pressure ratio output regulation, oil circuit on-off switching, and flow direction control in the same valve cavity, through an integrated spool design, it not only realizes the synchronization of oil circuit commutation and pressure ratio adaptive regulation, but also greatly reduces the control difficulty of braking.

[0039] The cartridge valve generally refers to a two-way logic valve formed by standardizing the design of the valve block and then inserting the spool into the pre-machined installation hole of the valve block. The existing proportional valves and directional valves are all cartridge valves. When the cartridge valves are integrally designed, generally multiple spools are installed in the same valve block, and each cartridge valve needs to separately occupy the installation hole of the valve block, resulting in a large valve block and being difficult to install and maintain in some narrow spaces.

[0040] The brake control valve in the embodiment of the present invention also breaks through the limitations of the stacking layout of cartridge valves during integration. It adopts an embedded flow channel design and an axially integrated composite valve core structure, which can be directly adapted to the narrow valve group space of compact equipment. Through integration, deployment can be completed only by single-point positioning installation, which greatly reduces the workload of disassembly and assembly of the valve body 11 during maintenance, and there are fewer fault points that need to be checked when a fault occurs, reducing the workload of maintenance personnel.

[0041] like Figure 2 As shown, in an embodiment of the present invention, the reset drive oil port 112 a is connected to the brake working oil port A via a bypass oil passage 113 on the valve body 11 , and a throttling damping device 13 may be provided in the bypass oil passage 113 .

[0042] That is, the reset drive oil port 112a and the brake working oil port A can be throttled and connected. Through the throttling damping device 13, when the oil inlet P and the brake working oil port A are just connected, the elastic reset force generated by the reset drive oil port 112a at the reset end 112 can be reduced to a certain extent, ensuring that the control valve core 12 can quickly switch to the first valve position 1a, increasing the response speed of the brake control valve. At the same time, it is also convenient to fine-tune the reset force of the reset end 112, improve the control accuracy of the proportional output, and when the oil pressure of the oil inlet P fluctuates greatly, the throttling damping device 13 can also perform filtering to avoid external disturbances from interfering with the position of the control valve core 12.

[0043] That is, the brake control valve in the embodiment of the present invention is provided with two layers of structural protection to achieve smooth control of the braking force. One is to relieve the pressure on the oil inlet P at all times when no braking operation is performed. The other is to filter the interference of the oil pressure fluctuation of the brake working oil port A on the moving position of the control valve core 12 through the throttling damping device 13 when the braking operation is just performed.

[0044] In the embodiment of the present invention, the throttling damping device 13 is preferably a throttling plug detachably arranged in the bypass oil passage, and a throttling damping hole is arranged on the throttling plug. The throttling plug can be detachably installed in the bypass oil passage 113 by means of threads, and the size of the throttling damping hole can be adjusted by disassembling and replacing different throttling devices.

[0045] like Figure 2 and Figure 3 As shown, in the embodiment of the present invention, the axial end of the control valve core 12 close to the reset end 112 is the first driving end, and the first driving end is provided with a reset working groove 121, and the reset working groove 121 is aligned and communicated with the reset driving oil port 112a on the valve body 11. When hydraulic oil flows into the reset driving oil port 112a, it acts on the groove shoulder of the reset working groove 121 to apply an axial thrust to the control valve core 12, and the direction of the axial thrust points to the brake control end 111.

[0046] As Figure 2 and Figure 3 shown, in the embodiment of the present invention, a limiting step 123 is further provided on the first driving end. The spring 15 is sleeved on the first driving end and is in pressing abutting cooperation with the limiting step 123. The spring 15 is used to push the control valve core 12 towards the braking control end 111. By providing the limiting step 123, it is convenient for the spring 15 to apply a thrust to the control valve core 12 in the direction of the braking control end 111.

[0047] As Figure 2 and Figure 3 shown, in the embodiment of the present invention, a plug 14 is provided on the reset end 112 of the valve body 11. The spring 15 is elastically abutted between the plug 14 and the limiting step 123. By providing the plug 14, it is convenient for the spring 15 to be in pressing abutting cooperation with the limiting step 123.

[0048] As Figure 2 and Figure 3 shown, in the embodiment of the present invention, the braking control valve may be a hydraulically controlled directional valve. The driving structure includes a braking control oil port 111a provided on the braking control end 111 of the valve body 11. The braking control oil port 111a is used to be externally connected to the braking control oil circuit of the hydraulic system. The axial end of the control valve core 12 close to the braking control end 111 is the second driving end. A braking working groove 122 is provided on the second driving end. The braking working groove 122 is in alignment and communication with the braking control oil port 111a. When performing a braking operation, the oil fluid of the external braking control oil circuit will enter the braking control oil port 111a and act on the shoulder of the braking working groove 122 to apply an axial thrust to the control valve core 12 in the direction of the reset end 112. By providing the braking working groove 122, the driving of the control valve core 12 to switch from the second valve position 1b to the first valve position 1a is realized.

[0049] Among them, when the braking control valve is in the first valve position, the axial thrust generated by the braking working groove 122 will be balanced with the axial thrust of the reset working groove 121 and the axial thrust of the spring to achieve the proportional output of the braking control valve.

[0050] In the embodiment of the present invention, the braking control valve may also be an electrically controlled directional valve. The commutation of the braking control end 111 can be realized by an electromagnet, and the driving control signal of the braking control end 111 is an electrical signal.

[0051] In the embodiment of the present invention, the diameter of the shoulder cross-section of the braking working groove 122 is preferably larger than the diameter of the shoulder cross-section of the reset working groove 121 to ensure that the control valve core 12 can smoothly switch from the second valve position 1b to the first valve position 1a. Of course, the smooth commutation of the control valve core 12 can also be realized by the method of driving the two grooves with different oil pressures.

[0052] Further, as Figure 2 andFigure 3 As shown, the axial two ends of the control spool 12 are respectively a first driving end and a second driving end, and the diameter of the second driving end is preferably larger than that of the first driving end. Since the braking working groove 122 is arranged on the second control end of the control spool 12 and the reset working groove 121 is arranged on the first control end of the control spool 12, setting the diameter of the second driving end to be larger than that of the first driving end not only makes it easier to achieve that the shoulder cross-sectional area of the braking working groove 122 is larger than that of the reset working groove 121, but also the second driving end with a larger diameter is convenient for sealing the valve cavity channel to avoid oil leakage between different oil ports.

[0053] In an embodiment of the present invention, a spring installation cavity is provided at the reset end 112 of the valve body 11. The spring installation cavity is communicated with the valve cavity channel. The first driving end of the control spool 12 extends into the spring installation cavity, and the first driving end also seals and abuts against the inner wall of the cavity of the valve cavity channel through a sealing ring 16. The sealing ring 16 is used to separate the valve cavity channel from the spring installation cavity.

[0054] To achieve the above object, the present invention also provides a hydraulic braking system. The hydraulic braking system at least includes a braking execution element (such as a brake cylinder or a brake caliper), a hydraulic power unit (a hydraulic pump), a braking operation unit (such as a brake pedal), and the braking control valve described above. The braking operation unit can be connected to the braking control end of the valve through a braking control oil circuit.

[0055] The braking control valve in the embodiment of the present invention is used as the control core of the hydraulic braking system and adopts an integrated design, integrating the functions of an independent reversing valve and a proportional pressure reducing valve in the traditional scheme, realizing the integrated control of the reversing switching and pressure ratio adjustment of the braking oil circuit. It not only has a small volume and a compact structure, but also can synchronously realize the oil circuit reversing and the pressure ratio adaptive adjustment, realizing the flexible braking of the braking execution element, and greatly improving the braking effect of the system.

[0056] To achieve the above object, the present invention also provides a working machine. The working machine includes the hydraulic braking system described above. The working machine can be an agricultural tractor, a load skid steer loader, etc. Since the working machine adopts all the technical solutions of the above embodiment, it at least has the beneficial effects brought by the above embodiment, which will not be repeated here.

[0057] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0058] In the present invention, unless otherwise clearly specified or limited, terms such as "installed", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, or capable of communicating with each other; it may be directly connected, or indirectly connected through an intermediate medium, and may be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0059] In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, without conflict, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0060] Although the embodiments of the present invention have been described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A brake control valve, characterized in that, The brake control valve is provided with an oil inlet (P), an oil return port (T), and a brake working oil port (A). The brake control valve is further provided with a first valve position (1a), a second valve position (1b), and brake control ends (111) and a reset end (112) at opposite ends; The first valve position (1a) is used to conduct the oil inlet (P) and the brake working oil port (A). The second valve position (1b) is used to conduct the oil return port (T) with the brake working oil port (A) and the oil inlet (P) respectively; The brake control end (111) is used to control the brake control valve to switch to the first valve position (1a), and the reset end (112) is used to drive the brake control valve to reset to the second valve position (1b).

2. The brake control valve according to claim 1, characterized in that, The brake control valve includes a valve body (11) and a control spool (12). The oil inlet (P), the oil return port (T), and the brake working oil port (A) are arranged on the valve body (11). The control spool (12) is movably arranged in the valve cavity channel of the valve body (11). The two ends of the valve cavity channel are respectively the brake control end (111) and the reset end (112) of the valve body (11); A driving structure for driving the control spool (12) to move towards the reset end (112) is arranged on the brake control end (111). The reset end (112) is provided with a spring (15) and a reset driving oil port (112a) that are jointly used to drive the control spool (12) to move towards the brake control end (111). The reset driving oil port (112a) is communicated with the brake working oil port (A).

3. The brake control valve according to claim 2, characterized in that, The reset driving oil port (112a) is communicated with the brake working oil port (A) through a bypass oil passage (113) on the valve body (11). A throttling damping device (13) is arranged in the bypass oil passage (113).

4. The brake control valve according to claim 2, characterized in that, One axial end of the control spool (12) close to the reset end (112) is a first driving end. A reset working groove (121) is arranged on the first driving end. The reset working groove (121) is in alignment communication with the reset driving oil port (112a) on the valve body (11).

5. The brake control valve according to any one of claims 2-4, characterized in that, One axial end of the control spool (12) close to the reset end (112) is a first driving end. A limiting step (123) is further arranged on the first driving end. The spring (15) is sleeved on the first driving end and abuts against the limiting step (123). The spring (15) is used to push the control spool (12) in the direction of the brake control end (111).

6. The brake control valve according to claim 5, characterized in that, A plug (14) is arranged on the reset end (112) of the valve body (11). The spring (15) elastically abuts between the plug (14) and the limiting step (123).

7. The brake control valve according to claim 2, wherein, The driving structure includes a brake control oil port (111a) provided on the brake control end (111) of the valve body (11). The brake control oil port (111a) is used to be externally connected to the brake control oil circuit of the hydraulic system. The axial end of the control spool (12) close to the brake control end (111) is the second driving end, and a brake working groove (122) is provided on the second driving end. The brake working groove (122) is in alignment and communication with the brake control oil port (111a).

8. The brake control valve according to claim 2, wherein, The axial end of the control spool (12) close to the reset end (112) is the first driving end, and the end close to the brake control end (111) is the second driving end. The diameter of the second driving end is larger than that of the first driving end.

9. A hydraulic braking system, characterized in that, It includes the brake control valve according to any one of claims 1 to 8.

10. An earthmoving machine, characterized in that, It includes the hydraulic brake system according to claim 9.

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