A new energy tractor front axle brake control system and tractor

Abstract

The present application relates to tractor technology field, especially a new energy tractor front axle brake control system and tractor, left rear axle brake assembly and front axle brake control valve group RL port communication, right rear axle brake assembly and front axle brake control valve group RR port communication, front axle brake and front axle brake control valve group B port communication, variable plunger pump output and front axle brake control valve group P port communication, variable plunger pump variable control end and front axle brake control valve group LS port communication;Front axle brake control valve group is configured to when RL port and RR port have hydraulic oil input, P port and B port are communicated to make variable plunger pump oil supply to front axle brake.The present application is through setting up and rear axle brake linkage front axle brake control structure, realize when left and right rear axle brake, can realize front axle brake simultaneously, improve the braking force of tractor;When rear axle unilateral brake, will not pneumatic front axle brake, ensure the safety of front axle brake.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of tractor technology, and particularly relates to a new energy tractor front axle brake control system and a tractor. BACKGROUND

[0002] With the increasing speed of new energy tractors, the maximum speed design has reached 50KM / h, and the braking requirements of new energy tractors are becoming more and more stringent. The braking force of the rear wheel alone cannot meet the braking demand, and the front axle also needs to be braked.

[0003] The existing front axle brake system usually adopts a plunger pump to directly input hydraulic oil to the front axle brake for braking, which belongs to another set of brake system independent of the rear axle brake system, and needs to be controlled by the driver alone to inject hydraulic pressure. This setting may have the following problems: when the rear axle is braked unilaterally, if the front axle brake is also turned on, it may cause the tractor to deviate from the driving direction, and even cause the tractor to roll over, causing safety accidents. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a new energy tractor front axle brake control system and a tractor to solve the deficiencies in the prior art.

[0005] The technical scheme for solving the above technical problem is as follows: a new energy tractor front axle brake control system, comprising a left rear axle brake assembly, a right rear axle brake assembly, a front axle brake, a variable plunger pump and a front axle brake control valve group, the left rear axle brake assembly is in communication with the RL port of the front axle brake control valve group, the right rear axle brake assembly is in communication with the RR port of the front axle brake control valve group, the front axle brake is in communication with the B port of the front axle brake control valve group, the output end of the variable plunger pump is in communication with the P port of the front axle brake control valve group, and the variable control end of the variable plunger pump is in communication with the LS port of the front axle brake control valve group; the front axle brake control valve group is configured to communicate the P port with the B port when hydraulic oil is input to the RL port and the RR port, so that the variable plunger pump supplies oil to the front axle brake.

[0006] The beneficial effects of the present application are: by setting the front axle brake control structure linked with the rear axle brake, the front axle brake can be realized when the left and right rear axles are braked at the same time, the braking force of the tractor is improved; at the same time, when the rear axle is braked unilaterally, the front axle brake will not be braked pneumatically, and the safety of the front axle brake is ensured.

[0007] On the basis of the above technical scheme, the present application can also be improved as follows.

[0008] Further, the front axle brake control valve group comprises a counter shuttle valve and a hydraulic control pressure reducing valve, two input ports of the counter shuttle valve are communicated with the RL port and the RR port respectively, an output port of the counter shuttle valve is communicated with a spool control port of the hydraulic control pressure reducing valve, the hydraulic control pressure reducing valve is provided with a first connecting port and a second connecting port, the first connecting port is communicated with the B port, the second connecting port is communicated with the A port and the P port, a one-way valve is arranged on a connecting channel of the P port and the second connecting port, the hydraulic control pressure reducing valve is configured to be in communication between the first connecting port and the second connecting port when the spool control port receives the hydraulic oil output by the output port of the counter shuttle valve, and be in disconnection between the first connecting port and the second connecting port when the spool control port does not receive the hydraulic oil output by the output port of the counter shuttle valve.

[0009] The beneficial effect of the above further scheme is that the two input ports of the counter shuttle valve are communicated with the RL port and the RR port respectively, so that when the RL port and the RR port both have hydraulic input, i.e. the left rear axle brake assembly and the right rear axle brake assembly work at the same time, the output port of the counter shuttle valve has hydraulic output, thereby enabling the control of the spool of the hydraulic control pressure reducing valve, enabling the A port and the B port to be in communication, and thereby enabling the variable plunger pump to deliver hydraulic oil to the front axle brake, so as to brake the front axle; when the RL port and the RR port both have no hydraulic oil input or only one has hydraulic oil input, the output port of the counter shuttle valve has no hydraulic output, the A port and the B port are in disconnection, the front axle brake has no working oil input, and the front axle brake cannot realize braking, thereby ensuring the safety during braking.

[0010] Further, the A port of the front axle brake control valve group is communicated with an accumulator, and the front axle brake control valve group is configured to be in communication between the A port and the P port when the RL port and the RR port both have hydraulic oil input, so as to enable the accumulator or the variable plunger pump to supply oil to the front axle brake, and be in communication between the A port and the P port when the oil port of the accumulator has a pressure less than a minimum set value, so as to enable the variable plunger pump to supplement oil to the accumulator until the oil port of the accumulator has a pressure restored to a maximum set value.

[0011] The beneficial effect of the above further scheme is that the accumulator can provide hydraulic oil for the front axle brake when the variable plunger pump fails, thereby solving the problem that the new energy tractor can still brake when the braking energy fails, and ensuring the safety of the whole vehicle; and the variable plunger pump can supplement oil to the accumulator in time according to the pressure of the oil port of the accumulator, thereby ensuring the pressure of the oil in the accumulator.

[0012] Further, the front axle brake control valve group is provided with an LS port, and further comprises a shuttle valve and an electromagnetic reversing valve, the electromagnetic reversing valve is provided with a third connecting port and a fourth connecting port, the third connecting port is communicated with the P port, the fourth connecting port is communicated with one input port of the shuttle valve, another input port of the shuttle valve is communicated with the B port, the output port of the shuttle valve is communicated with the LS port, the LS port is communicated with the variable control port of the variable piston pump, and the electromagnetic reversing valve can be switched to be in communication or disconnected between the third connecting port and the fourth connecting port.

[0013] The beneficial effect of the above further scheme is that the electromagnetic reversing valve can control the start and stop of the variable piston pump, and the shuttle valve can detect whether the B port has input, and when the B port has oil input, the output port of the shuttle valve delivers oil to the variable control port of the variable piston pump, and the variable piston pump adjusts the output oil pressure according to the pressure of the B port.

[0014] Further, the oil tank is further provided, the front axle brake control valve group is provided with a T1 port and a T2 port, the T1 port and the T2 port are both communicated with the oil tank, the input end of the variable piston pump is communicated with the oil tank, the hydraulic control pressure reducing valve is provided with a fifth connecting port, the fifth connecting port is communicated with the T1 port, the first connecting port and the fifth connecting port are communicated when the valve core control port of the hydraulic control pressure reducing valve does not receive the output of the output port of the shuttle valve, the electromagnetic reversing valve is provided with a sixth connecting port, the sixth connecting port is communicated with the T2 port, and the electromagnetic reversing valve can be switched to be in communication or disconnected between the third connecting port and the fourth connecting port or between the fourth connecting port and the sixth connecting port.

[0015] The beneficial effect of the above further scheme is that the oil tank can recycle the oil in the hydraulic control pressure reducing valve and the electromagnetic reversing valve.

[0016] Further, the front axle brake control valve group is provided with an M port, the M port is communicated with the output port of the shuttle valve, and the M port is communicated with a first pressure sensor for checking the pressure of the output port of the shuttle valve.

[0017] The beneficial effect of the above further scheme is that the first pressure sensor can detect the oil pressure of the output port of the shuttle valve, and thus the input pressure of the hydraulic control pressure reducing valve can be conveniently pilot controlled.

[0018] Further, the oil port of the accumulator is provided with a second pressure sensor for detecting the oil port pressure of the accumulator.

[0019] The beneficial effect of the above further scheme is that the second pressure sensor can detect the pressure of the oil port of the accumulator in real time, and thus the accumulator can be conveniently and timely replenished with oil.

[0020] Further, the left rear axle brake assembly comprises a left rear axle brake pedal oil cylinder and a left rear axle brake, an input port of the left rear axle brake pedal oil cylinder is communicated with the brake oil pot, and an output port of the left rear axle brake pedal oil cylinder is communicated with the left rear axle brake and the RL port.

[0021] The beneficial effect of the further scheme is that when the left rear axle brake pedal is stepped on, hydraulic oil in the left rear axle brake pedal oil cylinder is delivered to the left rear axle brake to realize left rear axle braking, and part of the oil can be delivered to the RL port.

[0022] Further, the right rear axle brake assembly comprises a right rear axle brake pedal oil cylinder and a right rear axle brake, an input port of the right rear axle brake pedal oil cylinder is communicated with the brake oil pot, and an output port of the right rear axle brake pedal oil cylinder is communicated with the right rear axle brake and the RR port.

[0023] The beneficial effect of the further scheme is that when the right rear axle brake pedal is stepped on, hydraulic oil in the right rear axle brake pedal oil cylinder is delivered to the right rear axle brake to realize right rear axle braking, and part of the oil can be delivered to the RR port.

[0024] The present application solves the above-mentioned problems and further provides a tractor comprising the new energy tractor front axle brake control system.

[0025] The beneficial effect of the above-mentioned scheme is that the present application sets the front axle brake control structure linked with the rear axle brake, so that when the left and right rear axles are braked at the same time, the front axle brake can be realized at the same time, and the braking force of the tractor is improved; at the same time, when the rear axle is braked on one side, the front axle brake will not be pneumatically braked, and the safety of the front axle brake is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 Fig. 1 is a structural schematic diagram of the new energy tractor front axle brake control system in the present application;

[0027] Figure 2 Fig. 3 is a schematic diagram of the state of the rear axle unilateral braking in the new energy tractor front axle brake control system in the present application, and the thick black lines and arrows in the figure represent the flow direction of the hydraulic oil.

[0028] Figure 3 Fig. 4 is a schematic diagram of the state of the front axle brake in the new energy tractor front axle brake control system in the present application, and the thick black lines and arrows in the figure represent the flow direction of the hydraulic oil.

[0029] Figure 4 Fig. 5 is a schematic diagram of the state of the rear axle unilateral braking in the new energy tractor front axle brake control system in the present application, and the thick black lines and arrows in the figure represent the flow direction of the hydraulic oil.

[0030] The attached diagram lists the components represented by each number as follows:

[0031] 1. Front axle brake;

[0032] 2. Accumulator;

[0033] 3. Variable displacement piston pump;

[0034] 4. Front axle brake control valve assembly;

[0035] 4.1 Reverse shuttle valve; 4.2 Hydraulic pressure reducing valve; 4.3 Check valve; 4.4 Shuttle valve; 4.5 Solenoid directional valve;

[0036] 5. Fuel tank;

[0037] 6. First pressure sensor;

[0038] 7. Second pressure sensor;

[0039] 8. Left rear axle brake pedal cylinder;

[0040] 9. Left rear axle brake;

[0041] 10. Brake fluid reservoir;

[0042] 11. Right rear axle brake pedal cylinder;

[0043] 12. Right rear axle brake. Detailed Implementation

[0044] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0045] Example 1

[0046] like Figure 1 As shown, this embodiment discloses a front axle braking control system for a new energy tractor, including a left rear axle braking assembly, a right rear axle braking assembly, a front axle brake 1, a variable displacement piston pump 3, and a front axle brake control valve group 4. The left rear axle braking assembly is connected to the RL port of the front axle brake control valve group 4, the right rear axle braking assembly is connected to the RR port of the front axle brake control valve group 4, the front axle brake 1 is connected to the B port of the front axle brake control valve group 4, the output end of the variable displacement piston pump 3 is connected to the P port of the front axle brake control valve group 4, and the variable control end of the variable displacement piston pump 3 is connected to the LS port of the front axle brake control valve group 4. The front axle brake control valve group 4 is configured such that when hydraulic oil is input to both the RL port and the RR port, the P port is connected to the B port so that the variable displacement piston pump 3 supplies oil to the front axle brake 1.

[0047] The number of the front axle brake 1 in the embodiment can be two, and the two front axle brakes 1 brake the left front axle and the right front axle of the tractor respectively.

[0048] In the embodiment, the front axle brake control valve group 4 comprises a counter shuttle valve 4.1 and a hydraulic control pressure reducing valve 4.2, two input ports of the counter shuttle valve 4.1 are communicated with the RL port and the RR port respectively, an output port of the counter shuttle valve 4.1 is communicated with a spool control port of the hydraulic control pressure reducing valve 4.2, the hydraulic control pressure reducing valve 4.2 is provided with a first connecting port and a second connecting port, the first connecting port is communicated with the B port, the second connecting port is communicated with the A port and the P port, a one-way valve 4.3 is arranged on a connecting channel of the P port and the second connecting port, the arrangement of the one-way valve 4.3 can avoid the hydraulic oil of the B port and the A port flowing back to the variable piston pump 3, the hydraulic control pressure reducing valve 4.2 is configured to be communicated with the first connecting port and the second connecting port when the spool control port receives the hydraulic oil output by the output port of the counter shuttle valve 4.1, and to be disconnected when the spool control port does not receive the hydraulic oil output by the output port of the counter shuttle valve 4.1. The two input ports of the counter shuttle valve 4.1 are communicated with the RL port and the RR port respectively, so that when the RL port and the RR port have hydraulic input, that is, the left rear axle brake assembly and the right rear axle brake assembly work at the same time, the output port of the counter shuttle valve 4.1 has hydraulic output, thereby enabling the spool of the hydraulic control pressure reducing valve 4.2 to be controlled, enabling the A port and the B port to be communicated, and thereby enabling the variable piston pump 3 to deliver hydraulic oil to the front axle brake 1 to brake the front axle; when the RL port and the RR port have no hydraulic oil input or only one has hydraulic oil input, the output port of the counter shuttle valve 4.1 has no hydraulic output, the A port and the B port are in a disconnected state, the front axle brake 1 has no working oil input, and the front axle brake 1 cannot brake, thereby ensuring the safety during braking.

[0049] Further, the A port of the front axle brake control valve group 4 is communicated with the accumulator 2, the front axle brake control valve group 4 is configured to be communicated with the B port through the A port and the P port when the RL port and the RR port have hydraulic oil input, so that the accumulator 2 or the variable piston pump 3 supplies oil to the front axle brake 1, and the A port is communicated with the P port when the pressure of the oil port of the accumulator 2 is less than the lowest set value, so that the variable piston pump 3 supplements oil to the accumulator 2 until the pressure of the oil port of the accumulator 2 recovers to the highest set value. The arrangement of the accumulator 2 can provide hydraulic oil for the front axle brake when the variable piston pump 3 fails, thereby solving the problem that the new energy tractor can still brake when the braking energy fails, and ensuring the safety of the whole vehicle; the variable piston pump 3 supplements oil to the accumulator 2 in time according to the pressure of the oil port of the accumulator 2, thereby ensuring the pressure of the oil in the accumulator 2.

[0050] The front axle brake control valve group 4 is provided with an LS port, and further comprises a shuttle valve 4.4 and an electromagnetic reversing valve 4.5, the electromagnetic reversing valve 4.5 is provided with a third connecting port and a fourth connecting port, the third connecting port is in communication with the P port, the fourth connecting port is in communication with one input port of the shuttle valve 4.4, the other input port of the shuttle valve 4.4 is in communication with the B port, the output port of the shuttle valve 4.4 is in communication with the LS port, the LS port is in communication with the variable control port of the variable piston pump 3, and the electromagnetic reversing valve 4.5 can be switched to be in communication or disconnected between the third connecting port and the fourth connecting port. The setting of the electromagnetic reversing valve 4.5 can control the start and stop of the variable piston pump 3; at the same time, whether the B port has input can be detected according to the shuttle valve 4.4, when the B port has oil input, the output port of the shuttle valve 4.4 delivers oil to the variable control port of the variable piston pump 3, and the variable piston pump 3 adjusts the output oil pressure according to the pressure condition of the B port.

[0051] In the embodiment, an oil tank 5 is further included, the front axle brake control valve group 4 is provided with a T1 port and a T2 port, the T1 port and the T2 port are both in communication with the oil tank 5, the input end of the variable piston pump 3 is in communication with the oil tank 5, the hydraulic control pressure reducing valve 4.2 is provided with a fifth connecting port, the fifth connecting port is in communication with the T1 port, when the valve core control port of the hydraulic control pressure reducing valve 4.2 does not receive the output of the output port of the reverse shuttle valve 4.1, the first connecting port and the fifth connecting port are in communication; the electromagnetic reversing valve 4.5 is provided with a sixth connecting port, the sixth connecting port is in communication with the T2 port, and the electromagnetic reversing valve 4.5 can be switched to be in communication between the third connecting port and the fourth connecting port or between the fourth connecting port and the sixth connecting port. The setting of the oil tank 5 can recycle the oil in the hydraulic control pressure reducing valve 4.2 and the electromagnetic reversing valve 4.5.

[0052] The front axle brake control valve group 4 is provided with an M port, the M port is in communication with the output port of the reverse shuttle valve 4.1, and the M port is in communication with a first pressure sensor 6 for checking the pressure of the output port of the reverse shuttle valve 4.1. The setting of the first pressure sensor 6 can detect the oil pressure of the output port of the reverse shuttle valve 4.1, and then facilitate the pilot control of the input pressure of the hydraulic control pressure reducing valve 4.2.

[0053] The oil port of the accumulator 2 is provided with a second pressure sensor 7 for detecting the oil port pressure of the accumulator 2. The setting of the second pressure sensor 7 can detect the pressure of the oil port of the accumulator 2 in real time, and facilitate timely oil supplement for the accumulator 2.

[0054] The left rear axle braking assembly includes a left rear axle brake pedal cylinder 8 and a left rear axle brake 9. The input port of the left rear axle brake pedal cylinder 8 is connected to the brake fluid reservoir 10, and the output port of the left rear axle brake pedal cylinder 8 is connected to the left rear axle brake 9 and the RL port. By depressing the left rear axle brake pedal, the hydraulic oil in the left rear axle brake pedal cylinder 8 is delivered to the left rear axle brake 9 to achieve left rear axle braking, while some oil is simultaneously delivered to the RL port.

[0055] The right rear axle braking assembly includes a right rear axle brake pedal cylinder 11 and a right rear axle brake 12. The input port of the right rear axle brake pedal cylinder 11 is connected to the brake fluid reservoir 10, and the output port of the right rear axle brake pedal cylinder 11 is connected to the right rear axle brake 12 and the RR port. By depressing the right rear axle brake pedal, hydraulic oil in the right rear axle brake pedal cylinder 11 is delivered to the right rear axle brake 12 to achieve right rear axle braking, while some oil is simultaneously delivered to the RR port.

[0056] In this embodiment, the left rear axle brake pedal cylinder 8 and the right rear axle brake pedal cylinder 11 are used to provide rear wheel braking force for service braking, and the brake fluid reservoir 10 is used to provide brake fluid. The left rear axle brake 9 and the right rear axle brake 12 are used to provide rear axle braking friction.

[0057] Working principle:

[0058] like Figure 2 As shown, the variable displacement piston pump 3 replenishes the accumulator 2 as follows: When the engine starts, the foot brake is not applied. The second pressure sensor 7 determines the pressure value of the accumulator 2. When the value of the second pressure sensor 7 is lower than the minimum set value (e.g., 80 bar), the controller controls the solenoid directional valve 4.5 to switch. At this time, the P port is connected to the LS port, and the variable displacement piston pump 3 operates to fill the accumulator 2 with fluid. This continues until the second pressure sensor 7 detects that the pressure value has reached the optimal set value (e.g., 160 bar). Then, the controller switches the solenoid directional valve 4.5 again, the variable displacement piston pump 3 loses the LS pressure signal, and stops working, completing the filling process. Because the accumulator 2 will retain a certain amount of power oil, even if the power source fails, during braking, the pressure in the accumulator 2 can still be used to release braking pressure to the front axle brake 1 through the hydraulic pressure reducing valve 4.2 for braking.

[0059] like Figure 3As shown, the working state of the front axle brake 1 braking is as follows: after the engine is started, at this time, when the left rear axle brake pedal oil cylinder 8 and the right rear axle brake pedal oil cylinder 11 are stepped down at the same time, the rear axle brake pressure reaches the left rear axle brake 9 and the right rear axle brake 12 respectively, and at the same time, the pressure is introduced into the valve core control port of the hydraulic control pressure reducing valve 4.2 through the reverse shuttle valve 4.1, the valve core is pushed to reverse, at this time, the A port is connected to the B port, and the B port feeds back the pressure to the LS port through the shuttle valve 4.4, so that the variable plunger pump 3 works. At the same time, the B port pressure is output to the front axle brake 1, realizing the front axle braking of the whole vehicle. The braking pressure of the front axle is controlled by the pressure ratio of the stepped RL and RR ports. The first pressure sensor 6 monitors the hydraulic pilot control pressure on the left side of the hydraulic control pressure reducing valve 4.2.

[0060] As shown in the figure, Figure 4 The working state of the rear axle unilateral braking is as follows: when only the left rear axle brake pedal oil cylinder 8 or the right rear axle brake pedal oil cylinder 11 is stepped down, as shown in the figure, Figure 4 Only the left rear axle brake pedal oil cylinder 8 is stepped down at this time, the reverse shuttle valve 4.1 blocks the pressure of the RL port to be delivered to the valve core control port of the hydraulic control pressure reducing valve 4.2, and the B port is connected to the T port, and the front axle has no braking pressure.

[0061] The embodiment realizes the front axle braking at the same time when the left and right rear axles are braked at the same time, improves the braking force of the tractor, and at the same time, when the rear axle is braked unilaterally, the front axle is not pneumatically braked, ensuring the safety of the front axle braking.

[0062] Embodiment two

[0063] The embodiment discloses a tractor, and specifically comprises the new energy tractor front axle brake control system.

[0064] The embodiment realizes the front axle braking at the same time when the left and right rear axles are braked at the same time, improves the braking force of the tractor, and at the same time, when the rear axle is braked unilaterally, the front axle is not pneumatically braked, ensuring the safety of the front axle braking.

[0065] In the description of the present application, it should be understood that the terms "center", "length", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "inner", "outer", "peripheral side", "circumferential" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the systems or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0066] In the description of the application, the meaning of "a plurality" is at least two, for example, two, three, etc., unless otherwise explicitly specified and limited.

[0067] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and other terms should be understood in a broad sense, for example, can be fixedly connected, can also be detachably connected, or integrated; can be mechanically connected, can also be electrically connected; can be directly connected, can also be indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship of two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0068] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" 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 application. In the present application, the illustrative description of the above terms is not necessarily for the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine the different embodiments or examples described in the present application and the features of the different embodiments or examples without contradiction.

[0069] The above is only the preferred embodiment of the present application, and is not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A new energy tractor front axle brake control system, characterized in that, The front axle brake control valve group (4) is configured to, when hydraulic oil is inputted into the RL port and the RR port, the P port is communicated with the B port to make the variable plunger pump (3) supply oil to the front axle brake (1); The front axle brake control valve group (4) comprises a counter shuttle valve (4.1) and a hydraulic control pressure reducing valve (4.2), two input ports of the counter shuttle valve (4.1) are communicated with the RL port and the RR port respectively, an output port of the counter shuttle valve (4.1) is communicated with a spool control port of the hydraulic control pressure reducing valve (4.2), the hydraulic control pressure reducing valve (4.2) is provided with a first connecting port and a second connecting port, the first connecting port is communicated with the B port, the second connecting port is communicated with the P port, a one-way valve (4.3) is arranged on a connecting channel between the P port and the second connecting port, the hydraulic control pressure reducing valve (4.2) is configured to, when the spool control port receives hydraulic oil outputted by the output port of the counter shuttle valve (4.1), the first connecting port and the second connecting port are communicated, and when the spool control port does not receive hydraulic oil outputted by the output port of the counter shuttle valve (4.1), the first connecting port and the second connecting port are disconnected; The A port of the front axle brake control valve group (4) is communicated with an accumulator (2), the front axle brake control valve group (4) is configured to, when hydraulic oil is inputted into the RL port and the RR port, the A port and the P port are both communicated with the B port to make the accumulator (2) or the variable plunger pump (3) supply oil to the front axle brake (1), when the pressure of the oil port of the accumulator (2) is less than a minimum set value, the A port is communicated with the P port to make the variable plunger pump (3) supply oil to the accumulator (2) until the pressure of the oil port of the accumulator (2) recovers to a maximum set value, when there is no hydraulic oil inputted into the RL port and the RR port or only one of them has hydraulic oil inputted, the output port of the counter shuttle valve (4.1) has no hydraulic output, the A port is in a disconnected state with the B port, and the front axle brake (1) has no working oil inputted; The front axle brake control valve group (4) further comprises a shuttle valve (4.4) and an electromagnetic reversing valve (4.5), the electromagnetic reversing valve (4.5) is provided with a third connecting port and a fourth connecting port, the third connecting port communicates with the P port, the fourth connecting port communicates with one input port of the shuttle valve (4.4), the other input port of the shuttle valve (4.4) communicates with the B port, the output port of the shuttle valve (4.4) communicates with the LS port, the LS port communicates with the variable control port of the variable piston pump (3), and the electromagnetic reversing valve (4.5) can be switched to communicate or disconnect the third connecting port and the fourth connecting port.

2. The new energy tractor front axle brake control system according to claim 1, characterized in that, Further comprising an oil tank (5), the front axle brake control valve group (4) is provided with a T1 port and a T2 port, both the T1 port and the T2 port communicate with the oil tank (5), the input end of the variable piston pump (3) communicates with the oil tank (5), the fifth connecting port of the hydraulic control pressure reducing valve (4.2) communicates with the T1 port, and the first connecting port and the fifth connecting port communicate when the valve core control port of the hydraulic control pressure reducing valve (4.2) does not receive the hydraulic oil output by the output port of the reverse shuttle valve (4.1); the electromagnetic reversing valve (4.5) is provided with a sixth connecting port, the sixth connecting port communicates with the T2 port, and the electromagnetic reversing valve (4.5) can be switched to communicate the third connecting port and the fourth connecting port or communicate the fourth connecting port and the sixth connecting port.

3. The new energy tractor front axle brake control system according to claim 1, characterized in that, The front axle brake control valve group (4) is provided with an M port, the M port communicates with the output port of the reverse shuttle valve (4.1), and the M port communicates with a first pressure sensor (6) for checking the pressure of the output port of the reverse shuttle valve (4.1).

4. The new energy tractor front axle brake control system according to claim 1, characterized in that, A second pressure sensor (7) is arranged at the oil port of the accumulator (2) to detect the oil port pressure of the accumulator (2).

5. The new energy tractor front axle brake control system according to any one of claims 1 to 4, characterized in that, The left rear axle brake assembly comprises a left rear axle brake pedal oil cylinder (8) and a left rear axle brake (9), the input port of the left rear axle brake pedal oil cylinder (8) communicates with a brake oil tank (10), and the output port of the left rear axle brake pedal oil cylinder (8) communicates with the left rear axle brake (9) and the RL port.

6. The new energy tractor front axle brake control system according to any one of claims 1 to 4, characterized in that, The right rear axle brake assembly comprises a right rear axle brake pedal oil cylinder (11) and a right rear axle brake (12), the input port of the right rear axle brake pedal oil cylinder (11) communicates with the brake oil tank (10), and the output port of the right rear axle brake pedal oil cylinder (11) communicates with the right rear axle brake (12) and the RR port.

7. A tractor characterised in that The new energy tractor front axle brake control system comprises the new energy tractor front axle brake control system according to any one of claims 1 to 6.

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