Brake control hydraulic system and working machine

Abstract

The invention belongs to the technical field of hydraulic braking, and discloses a braking control hydraulic system and an operation machine.The braking control hydraulic system comprises a controllable braking loop and a pedal braking loop, and the controllable braking loop comprises a first braking unit and a first oil supply path; a reversing control valve is arranged between the first oil supply way and a working oil way of the first brake unit, an on-off control element is further arranged on the working oil way of the first oil supply way, the pedal brake circuit comprises a second brake unit and a second oil supply way, and a working oil way of the second brake unit is connected to the first reversing end of the reversing control valve. And the first reversing end is used for controlling the reversing control valve to be switched to a conducting valve position. When the system is switched from a two-wheel braking mode to a four-wheel braking mode, the relation between braking force and the stroke of the pedal is kept constant.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydraulic braking, and in particular relates to a brake control hydraulic system and an operating machine. Background Art

[0002] Modern work machinery is equipped with different braking modes based on different driving scenarios. For example, to adapt to irregular terrain and slope operations, the braking system of a tractor is usually equipped with two modes: independent rear-wheel braking and four-wheel synchronous braking. The former only activates the rear wheel brakes, while the latter requires the simultaneous application of all four sets of front and rear wheel brakes.

[0003] To ensure synchronized front and rear wheel braking response in four-wheel synchronous braking mode, current mainstream hydraulic brake systems typically use a single brake pump to supply oil to all brakes. This system typically adds a distribution valve group between the brake pump and the front and rear wheel brakes to control the flow of hydraulic oil to achieve different braking modes.

[0004] The brake pump's output flow rate is positively correlated with pedal travel. When independent rear-wheel braking mode is engaged, the brake pump only supplies oil to the two rear brakes, resulting in lower system flow requirements. Consequently, a shorter pedal stroke is required to generate sufficient braking force. However, in four-wheel synchronous braking, the required flow rate for all four brakes doubles, forcing the operator to apply greater pedal force to achieve a deeper pedal stroke. This not only prolongs braking time and degrades braking performance, but also creates harsh pedal feedback, significantly impacting driving comfort. Summary of the Invention

[0005] In view of the above-mentioned defects or shortcomings, the present invention provides a brake control hydraulic system and an operating machine, aiming to solve the technical problem that the hydraulic brake system of the existing operating machine has relatively poor braking performance and driving comfort during four-wheel braking.

[0006] To achieve the above-mentioned objectives, the present invention provides a brake control hydraulic system, which includes a controllable braking circuit and a pedal braking circuit. The controllable braking circuit includes a first brake unit and a first oil supply circuit for supplying oil to the working oil circuit of the first brake unit. A reversing control valve for switching the on-off state is provided between the first oil supply circuit and the working oil circuit of the first brake unit. An on-off control element is also provided on the working oil circuit of the first oil supply circuit. The pedal braking circuit includes a second brake unit and a second oil supply circuit for supplying oil to the working oil circuit of the second brake unit. The working oil circuit of the second brake unit is connected to the first reversing end of the reversing control valve, and the first reversing end is used to control the reversing control valve to switch to the on valve position.

[0007] In an embodiment of the present invention, the second brake unit includes a first brake and a second brake respectively used to control the wheels on both sides of the first axle, and the working oil circuit of the second brake unit includes a first working oil circuit for guiding the hydraulic oil to the first brake and a second working oil circuit for guiding the hydraulic oil to the second brake. The first working oil circuit and the second working oil circuit are connected to the first reversing end of the reversing control valve through a shuttle valve.

[0008] In an embodiment of the present invention, the pedal brake circuit further includes a pedal assembly and a first pressure source, the first pressure source is connected to the second oil supply line, and the pedal assembly is used to control the flow of the first pressure source to the second oil supply line.

[0009] In an embodiment of the present invention, the pedal assembly includes a first pedal and a second pedal, the first pedal is used to control the oil flow rate of the first pressure source to the first working oil circuit, and the second pedal is used to control the oil flow rate of the first pressure source to the second working oil circuit.

[0010] In an embodiment of the present invention, a releasable linkage assembly is provided between the first pedal and the second pedal, and the linkage assembly is used to control the first pedal and the second pedal to move together.

[0011] In an embodiment of the present invention, the reversing control valve is provided with a conducting valve position and a shut-off valve position. The two ends of the reversing control valve are respectively a first reversing end for controlling the reversing control valve to switch to the conducting valve position and a spring return end for controlling the reversing control valve to switch to the shut-off valve position. A return spring is provided on the spring return end.

[0012] In an embodiment of the present invention, a feedback oil circuit is provided between the spring return end and the working oil circuit of the first brake unit, and a throttling damping element is provided on the feedback oil circuit.

[0013] In an embodiment of the present invention, the controllable braking circuit further includes a second pressure source for supplying oil to the first oil supply circuit, and the first oil supply circuit is further provided with a safety pressure relief oil circuit.

[0014] In an embodiment of the present invention, the on-off control element is a manual stop valve that is manually controlled to open and close, or the on-off control element is a solenoid valve or a hydraulic control valve that is remotely controlled to open and close.

[0015] To achieve the above-mentioned objectives, the present invention also provides an operating machine, wherein the operating machine includes a front axle, a rear axle and a brake control hydraulic system according to the above-mentioned method, the first brake unit is installed on one of the front axle and the rear axle, and the second brake unit is installed on the other of the front axle and the rear axle.

[0016] Through the above technical solution, the brake control hydraulic system provided by the embodiment of the present invention has the following beneficial effects: By turning the on / off control element on or off, the braking function of the controllable braking circuit can be correspondingly enabled or disabled, thereby switching the system between two-wheel braking mode and four-wheel braking mode. Because the controllable braking circuit and the pedal braking circuit are supplied with oil via two independent pressure sources, the relationship between pedal travel and the braking force of the second brake unit remains constant regardless of whether the controllable braking circuit is enabled or disabled. This avoids the need to press the pedal deeper for the same braking force, resulting in heavier pedal feedback, significantly enhancing driving comfort.

[0017] Furthermore, in four-wheel braking mode, when the operator depresses the brake pedal, the second oil supply circuit supplies oil to the working oil circuit of the second brake unit. The pressurized oil in the working oil circuit of the second brake unit not only drives the second brake unit but also flows to the first reversing end of the reversing control valve, connecting the first oil supply circuit to the working oil circuit of the first brake unit and causing the first brake unit to operate synchronously. In other words, by providing a reversing control valve within the controllable braking circuit and pilot-connecting the first reversing end of the reversing control valve to the working oil circuit of the second brake unit, this system achieves synchronous operation of the first and second brake units, provided that the first and second brake units are supplied with oil through two independent oil supply circuits.

[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 detailed description, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 is a hydraulic principle diagram of a brake control hydraulic system according to an embodiment of the present invention; Figure 2 is a front structural diagram of a brake according to an embodiment of the present invention; Figure 3 The brake according to the embodiment of the present invention is Figure 2 Cross-sectional view after cutting along AA from the viewing angle; Figure 4 FIG. 4 is a specific layout diagram of a brake control hydraulic system on a tractor according to an embodiment of the present invention.

[0020] Description of Reference Numerals 11. First brake unit; 12. First oil supply line; 111. Third brake; 13. Reversing control valve; 14. On-off control element; 15. Second pressure source; 16. Pressure relief valve; 21. Second brake unit; 211. First brake; 212. Second brake; 213. First working oil line; 214. Second working oil line; 22. Second oil supply line; 23. First pressure source; 24. Pedal assembly; 241. First pedal; 242. Second pedal; 31. Shuttle valve; 32. Throttling damping element; 41. Brake cylinder; 42. Friction plate group; 43. Brake spring; 44. Drain plug; 45. Bleed bolt; 51. Brake oil pot; 52. Fuel tank; 53. Filter; 54. Front axle; P, oil inlet; T, oil return port; A, working oil port. DETAILED DESCRIPTION

[0021] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0022] The brake control hydraulic system of the present invention will be described below with reference to the accompanying drawings.

[0023] The present invention discloses a novel brake control hydraulic system, such as Figure 1 As shown, the brake control hydraulic system includes a controllable brake circuit and a pedal brake circuit.

[0024] The controllable braking circuit includes a first brake unit 11 and a first oil supply circuit 12 for supplying oil to the working oil circuit of the first brake unit 11. A reversing control valve 13 for switching the on-off state is provided between the first oil supply circuit 12 and the working oil circuit of the first brake unit 11. The reversing control valve 13 has at least an on-valve position for connecting the first oil supply circuit 12 and the working oil circuit of the first brake unit 11 and a off-valve position for cutting off the first oil supply circuit 12 and the working oil circuit of the first brake unit 11. An on-off control element 14 is also provided on the working oil circuit of the first oil supply circuit 12, that is, when the on-off control element 14 is in the on-state, the controllable braking circuit is in the started state and participates in the braking of the entire vehicle. When the on-off control element 14 is in the off-state, the controllable braking circuit is removed, and only the pedal braking circuit participates in braking.

[0025] The pedal braking circuit refers to a braking circuit that is linked to the pedal in the cab. The pedal braking circuit includes a second brake unit 21 and a second oil supply circuit 22 for supplying oil to the working oil circuit of the second brake unit 21. The pedal in the cab is mainly used to control the flow of the second oil supply circuit 22 to the second brake unit 21. The working oil circuit of the second brake unit 21 is connected to the first reversing end of the reversing control valve 13, and the first reversing end is used to control the reversing control valve 13 to switch to the on valve position.

[0026] Among them, the first oil supply circuit 12 and the second oil supply circuit 22 are two independent oil supply circuits and are supplied with oil through independent pressure sources respectively. The pressure source of the first oil supply circuit 12 and the second oil supply circuit 22 can be a separate pump group, or one of several pressure oil circuits branched off from the main pump of the whole machine, or an accumulator, etc.

[0027] By turning on or off control element 14, the braking function of the controllable braking circuit can be correspondingly activated or deactivated, thereby switching the system between two-wheel braking mode and four-wheel braking mode. Because the controllable braking circuit and the pedal braking circuit are supplied with oil via two independent pressure sources, the relationship between pedal travel and the braking force of the second brake unit 21 remains constant regardless of whether the controllable braking circuit is activated or deactivated. This avoids the problem of requiring deeper pedal depression and heavier pedal feedback for the same braking force, significantly enhancing driving comfort.

[0028] Furthermore, in four-wheel braking mode, when the operator depresses the brake pedal, the second oil supply line 22 supplies oil to the working oil circuit of the second brake unit 21. The pressurized oil in the working oil circuit of the second brake unit 21 not only drives the second brake unit 21 but also flows to the first reversing end of the reversing control valve 13, thereby connecting the first oil supply line 12 to the working oil circuit of the first brake unit 11 and causing synchronous operation of the first brake unit 11. In other words, by providing the reversing control valve 13 within the controllable braking circuit and pilot-connecting the first reversing end of the reversing control valve 13 to the working oil circuit of the second brake unit 21, this system achieves synchronous braking of the first and second brake units 11, provided that the first and second brake units 11, 21, are supplied with oil through two independent oil supply lines.

[0029] like Figure 1 and Figure 4 As shown, in an embodiment of the present invention, the second brake unit 21 includes a first brake 211 and a second brake 212 respectively used to control the wheels on both sides of the first axle, and the working oil circuit of the second brake unit 21 includes a first working oil circuit 213 for guiding the hydraulic oil to the first brake 211 and a second working oil circuit 214 for guiding the hydraulic oil to the second brake 212. The first working oil circuit 213 and the second working oil circuit 214 are connected to the first reversing end of the reversing control valve 13 through a shuttle valve 31.

[0030] The first axle can be the front axle 54 or the rear axle in a two-axle working machine. That is, the two-wheel braking mode in this system can be the front two-wheel independent braking or the rear two-wheel independent braking.

[0031] In the four-wheel braking mode, when the operator steps on the pedal, the second oil supply circuit 22 will simultaneously supply oil to the first working oil circuit 213 and the second working oil circuit 214, causing the brakes on both sides of the first axle to operate simultaneously. If one of the first working oil circuit 213 and the second working oil circuit 214 leaks oil, and the first reversing end is only connected to the leaking working oil circuit, the oil leakage will cause the braking performance of the first brake unit 11 to drop significantly, or the first brake unit 11 will be unable to participate in the work, which is likely to cause a traffic accident. In this embodiment, the shuttle valve 31 selects the one with the higher pressure in the first working oil circuit 213 and the second working oil circuit 214, and directs the pressure oil of the one with the higher pressure to the first reversing end. When one of the first working oil circuit 213 and the second working oil circuit 214 leaks oil or cannot build pressure, the normal operation of the first brake unit 11 can still be guaranteed, thereby improving the safety of driving braking.

[0032] The pedal brake circuit includes, in addition to the second brake unit 21 and the second oil supply line 22, a pedal assembly 24 and a first pressure source 23. The first pressure source 23 is connected to the second oil supply line 22. The pedal assembly 24 controls the flow rate from the first pressure source 23 to the second oil supply line 22 based on the pedaling stroke. When the pedal assembly 24 has been pedaled to zero stroke, the input flow rate to the second oil supply line 22 is zero, and the second brake unit 21 is inoperative. As the operator depresses the pedal assembly 24, the input flow rate to the second oil supply line 22 gradually increases, correspondingly increasing the braking force generated by the second brake unit 21.

[0033] In order to achieve a smaller turning radius, some operating machinery will further optimize the system's braking mode, so that the system will have an additional rear single-wheel braking mode on the basis of the rear two-wheel braking mode. The implementation of the rear single-wheel braking requires two working oil circuits and two pedals to control the brakes on both sides of the rear axle respectively.

[0034] Specifically, in the embodiment of the present invention, the first axle may be a rear axle, and the pedal assembly 24 may include a first pedal 241 and a second pedal 242. The first pedal 241 is used to control the oil flow rate supplied by the first pressure source 23 to the first working oil circuit 213, and the second pedal 242 is used to control the oil flow rate supplied by the first pressure source 23 to the second working oil circuit 214. The first pedal 241 and the second pedal 242 are respectively a left pedal for controlling the left rear wheel and a right pedal for controlling the right rear wheel.

[0035] On the premise that the on-off control element 14 is turned off, the operator can realize a small-radius left turn of the machine by stepping on the first pedal 24 (1 pedal), controlling the steering wheel to turn left, and controlling the other three wheels to drive normally. The operator can realize a small-radius right turn of the machine by stepping on the right pedal, controlling the steering wheel to turn right, and controlling the other three wheels to drive normally.

[0036] In an embodiment of the present invention, a disengageable linkage assembly may be provided between the first pedal 241 and the second pedal 242. The linkage assembly is used to control the joint movement of the first and second pedals 241, 242. In four-wheel braking mode, by locking the first and second pedals 241, 242 via the linkage assembly, the operator only needs to depress either pedal to achieve four-wheel braking, greatly simplifying operation. In single-wheel braking mode, the linkage assembly can be disengaged, allowing the first and second pedals 241, 242 to be operated independently.

[0037] In an embodiment of the present invention, the linkage assembly may include an interlocking plate and a connecting member for detachably connecting the interlocking plate to the two pedals respectively. The connecting member may be a bolt, a pin, etc.

[0038] In an embodiment of the present invention, the first brake unit 11 may include a third brake 111 for controlling braking of the second axle. The second axle and the first axle are two adjacent axles. For a two-axle working machine, the first axle is generally one of the front axle 54 and the rear axle, and the second axle is generally the other of the front axle 54 and the rear axle.

[0039] like Figure 2 and Figure 3 As shown, in this embodiment of the present invention, the first brake 211, the second brake 212, and the third brake 111 are each composed of a brake cylinder 41 and a friction plate assembly 42. When oil is introduced into the brake cylinder 41, the friction plate assembly 42 is pushed into contact with the wheel hub of the axle, thereby braking the corresponding axle. The friction plate assembly 42 is reset by a brake spring 43. The brake cylinder 41 is also equipped with an oil drain plug 44 and an air bleed bolt 45. The oil drain plug 44 and the air bleed bolt 45 are used to drain oil and air from the cylinder during subsequent system maintenance.

[0040] like Figure 1 As shown, in this embodiment of the present invention, the directional control valve 13 has an on-valve position and a shut-off position. The two ends of the directional control valve 13 are a first reversing end for controlling the directional control valve 13 to switch to the on-valve position and a spring return end for controlling the directional control valve 13 to switch to the shut-off position. A return spring is provided on the spring return end. The return spring maintains the directional control valve 13 in the shut-off position when the pressure at the first reversing end is low.

[0041] like Figure 1As shown, the directional control valve 13 can be a two-position, four-way valve and is provided with an oil inlet P, an oil return port T, and a working oil port A. The oil inlet P is connected to the first oil supply line 12, the oil return port T is connected to the oil return line, and the working oil port A is connected to the working oil line of the first brake unit 11. In the on-valve position, the directional control valve 13 can be configured so that the oil inlet P and the working oil port A are connected. In the off-valve position, the directional control valve 13 can be configured so that both the oil inlet P and the working oil port A are connected to the oil return port T. Of course, the directional control valve 13 can also be arranged in other forms, such as a two-position, two-way directional valve with only an on-off function, or a two-position, three-way directional valve.

[0042] like Figure 1 As shown, during vehicle braking, the braking sequence and braking force distribution of the front and rear brakes are crucial issues. Different braking timings between the front and rear brakes can significantly impact vehicle stability and safety. In an embodiment of the present invention, a feedback oil circuit can be provided between the spring return end and the working oil circuit of the first brake unit 11. A throttling damping element 32 can be installed in this feedback oil circuit. By replacing the throttling damping element 32 with different specifications, the braking time and braking force of the first brake unit 11, from the start of the response to the completion of braking, can be adjusted. This can achieve the effect of the first brake unit 11 completing braking later than the second brake unit 21.

[0043] For example, for a two-axle work machine with a heavier rear end, the first brake unit 11 can be installed on the front axle 54, and the second brake unit 21 can be installed on the rear axle. When the work machine performs four-wheel braking, the front and rear axles can be braked simultaneously, but the rear axle brakes first, and the front axle 54 brakes later. This braking method can more easily achieve balanced braking force when the entire machine is braked. Of course, depending on the vehicle weight and product type of the work machine, the first brake unit 11 can be installed on the rear axle and the second brake unit 21 on the front axle 54 to achieve front wheel braking before rear wheel braking.

[0044] In the embodiment of the present invention, the throttling damping element 32 may be a damping screw plug.

[0045] like Figure 1 and Figure 4 As shown, in this embodiment of the present invention, the brake control hydraulic system further includes a second pressure source 15 for supplying oil to the first oil supply line 12. The second pressure source 15 and the first pressure source 23 are two independent pressure sources. The first oil supply line 12 is also provided with a safety pressure relief oil line, which is equipped with a pressure relief valve 16. The pressure relief valve 16 can guide excess hydraulic oil back to the oil tank 52 when the first brake unit 11 is fully actuated and the pressure in the first oil supply line 12 reaches a set value, thereby ensuring system safety.

[0046] In an embodiment of the present invention, the on-off control element 14 may be a manually controlled shutoff valve. An operator manually opens or closes the manual shutoff valve to activate or deactivate the controllable braking circuit. Alternatively, the on-off control element 14 may be a solenoid valve or a hydraulically controlled valve that is remotely activated or deactivated. An operator activates or deactivates the controllable braking circuit by manipulating a corresponding valve.

[0047] In the embodiment of the present invention, the on-off control element 14 , the reversing control valve 13 , the shuttle valve 31 , etc. may be provided separately or integrated into a valve group.

[0048] To achieve the above objectives, the present invention further provides a working machine, wherein the working machine includes a front axle 54, a rear axle, and the brake control hydraulic system described above, wherein a first brake unit 11 is installed on one of the front axle 54 and the rear axle, and a second brake unit 21 is installed on the other of the front axle 54 and the rear axle. The working machine can be a two-axle working machine such as a tractor, an agricultural harvester, or a loader skid steer.

[0049] If Figure 4 As an example, the illustrated brake control hydraulic system employs a specific layout on a tractor. The tractor primarily includes a front axle 54 and a rear axle (not shown). The front axle 54 is equipped with a first brake unit 11, while the rear axle is equipped with a second brake unit 21. The second brake unit 21 includes a first brake 211 and a second brake 212, respectively, for controlling the two rear wheels. The tractor also includes a first pedal 241, a second pedal 242, a brake oil reservoir 51, and a first pressure source 23. The first pressure source 23 can be a dual-chamber brake pump. The two working chambers of the dual-chamber brake pump draw hydraulic fluid from the brake oil reservoir 51 and, after piston pressurization, discharge the hydraulic fluid to the first brake 211 and the second brake 212, respectively. The tractor also includes a second pressure source 15. This can be an independent gear pump or a shared pressure source with the tractor's power steering cylinder, floor cooling pipes, and attachment lift cylinders. The tractor also includes a fuel tank 52 and a filter 53, which filters impurities from the fluid. A reversing control valve 13 and an on-off control element 14 are connected in series between the second pressure source 15 and the first brake unit 11 .

[0050] like Figure 1 and Figure 4As shown, when the tractor is in four-wheel braking mode, the on / off control element 14 can be opened, and the first and second pedals 241, 242 can be connected together via an interlocking plate. The operator simply presses on either the first or second pedal 241, 242. The adjustment screws on the first and second pedals 241, 242 push the pistons in the dual-chamber brake pumps. This causes the oil in the brake circuit to be pressurized by the pistons in the dual-chamber brake pumps and flow simultaneously to the first and second brakes 211, 212. This ultimately drives the friction pads within the brakes to press against the sidewalls of the wheels, braking the rear axle. Simultaneously, the pressurized oil in the working oil circuits of the first and second brakes 211, 212 flows through the shuttle valve 31 to the first reversing end of the directional control valve 13. This directional control valve 13 switches to the on position, and the hydraulic oil output from the second pressure source 15 enters the first brake unit 11 through the directional control valve 13, braking the second axle.

[0051] When the tractor needs to switch to the two-rear wheel braking mode, the on-off control element 14 can be closed, and the first pedal 241 and the second pedal 242 can be connected together through the interlocking plate. In this case, only the second brake unit 21 is in operation, and the first brake unit 11 is affected by the on-off control element 14 being cut off, and no hydraulic oil enters.

[0052] When the tractor needs to switch to the rear wheel individual braking mode, the on-off control element 14 can be turned off and the interlocking plate between the first pedal 241 and the second pedal 242 can be removed. At this time, the operator steps on the first pedal 241 or the second pedal 242 to brake the rear wheel on the corresponding side.

[0053] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0054] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0055] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction 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 can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0056] Although the embodiments of the present invention have been described above, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A brake control hydraulic system, characterized in that: The brake control hydraulic system includes: A controllable braking circuit comprises a first braking unit (11) and a first oil supply circuit (12) for supplying oil to the first braking unit (11); a reversing control valve (13) for switching an on-off state is provided between the first oil supply circuit (12) and a working oil circuit of the first braking unit (11); and an on-off control element (14) is further provided on the working oil circuit of the first oil supply circuit (12); The pedal brake circuit comprises a second brake unit (21) and a second oil supply circuit (22) for supplying oil to a working oil circuit of the second brake unit (21), wherein the working oil circuit of the second brake unit (21) is connected to a first reversing end of the reversing control valve (13), and the first reversing end is used to control the reversing control valve (13) to switch to a conduction valve position.

2. The brake control hydraulic system according to claim 1, characterized in that: The second brake unit (21) includes a first brake (211) and a second brake (212) for controlling wheels on both sides of the first axle respectively. The working oil circuit of the second brake unit (21) includes a first working oil circuit (213) for guiding hydraulic oil to the first brake (211) and a second working oil circuit (214) for guiding hydraulic oil to the second brake (212). The first working oil circuit (213) and the second working oil circuit (214) are connected to the first reversing end of the reversing control valve (13) through a shuttle valve (31).

3. The brake control hydraulic system according to claim 2, characterized in that: The pedal brake circuit further comprises a first pressure source (23) and a pedal assembly (24), wherein the first pressure source (23) is connected to the second oil supply circuit (22), and the pedal assembly (24) is used to control the flow rate of the first pressure source (23) to the second oil supply circuit (22).

4. The brake control hydraulic system according to claim 3, characterized in that: The pedal assembly (24) comprises a first pedal (241) and a second pedal (242), wherein the first pedal (241) is used to control the oil flow rate supplied by the first pressure source (23) to the first working oil circuit (213), and the second pedal (242) is used to control the oil flow rate supplied by the first pressure source (23) to the second working oil circuit (214).

5. The brake control hydraulic system according to claim 4, characterized in that: A releasable linkage component is provided between the first pedal (241) and the second pedal (242), and the linkage component is used to control the first pedal (241) and the second pedal (242) to move together.

6. The brake control hydraulic system according to claim 1, characterized in that: The reversing control valve (13) is provided with an on-valve position and a shut-off valve position. The two ends of the reversing control valve (13) are respectively the first reversing end for controlling the reversing control valve (13) to switch to the on-valve position and a spring return end for controlling the reversing control valve (13) to switch to the shut-off valve position. A return spring is provided on the spring return end.

7. The brake control hydraulic system according to claim 6, characterized in that: A feedback oil circuit is provided between the spring return end and the working oil circuit of the first brake unit (11), and a throttling damping element (32) is provided on the feedback oil circuit.

8. The brake control hydraulic system according to any one of claims 1 to 7, characterized in that: The controllable braking circuit further comprises a second pressure source (15) for supplying oil to the first oil supply circuit (12), and a safety pressure relief oil circuit is also provided on the first oil supply circuit (12).

9. The brake control hydraulic system according to any one of claims 1 to 7, characterized in that: The on-off control element (14) is a manual stop valve that is manually controlled to open and close, or the on-off control element (14) is a solenoid valve or a hydraulic control valve that is remotely controlled to open and close.

10. A working machine, characterized in that: include: The brake control hydraulic system according to any one of claims 1 to 9; A front axle (54) and a rear axle, the first brake unit (11) is mounted on one of the front axle (54) and the rear axle, and the second brake unit (21) is mounted on the other of the front axle (54) and the rear axle.

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