A three-stage braking system for a new energy tractor and a tractor

Abstract

The present invention relates to a three-stage braking system for a new energy tractor and a tractor. Among them, a three-stage braking system for a new energy tractor includes: a fuel tank; a right motor; a plunger pump, which is drivingly connected to the output end of the right motor and communicates with the fuel tank, an oil pipeline, and a load-sensing oil circuit; and a brake valve block assembly, which includes a brake master cylinder, a five-way four-position valve, a spring, and a brake. The five-way four-position valve is provided with an upper oil port a, a left oil port b, a middle oil port c, and a right oil port d, and has five working positions, and can be moved to any working position to connect the upper oil port a and the left oil port b, the oil ports are not connected to each other, the upper oil port a and the middle oil port c are connected, the right oil port d is simultaneously connected to the upper oil port a and the middle oil port c, or the right oil port d is connected to the upper oil port a. By adopting the technical solution of the present invention, the technical problem that the braking of the existing new energy tractor becomes heavier and heavier, affecting the user experience, can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of tractors, and particularly to a three-stage braking system for a new energy tractor and a tractor. Background Art

[0002] With the continuous increase in the horsepower of new energy tractors, the requirements for their braking systems are becoming increasingly strict. On the one hand, when operating, large-horsepower new energy tractors have higher speeds and greater inertia. In case of an emergency, the braking system is required to quickly and effectively decelerate or stop the vehicle to ensure the safety of operators and equipment. On the other hand, with the increase in horsepower, the burden on the braking system also increases correspondingly, resulting in a greater force required for braking and making the operation heavier and heavier, which greatly affects the user experience. Summary of the Invention

[0003] In view of the technical problem that the braking of existing new energy tractors is getting heavier and affecting the user experience, the present invention provides a three-stage braking system for a new energy tractor and a tractor.

[0004] The technical solution of the present invention to solve the above technical problems is as follows:

[0005] On the one hand, the present invention provides a three-stage braking system for a new energy tractor, comprising:

[0006] A fuel tank;

[0007] A right motor;

[0008] A plunger pump, which is drivingly connected to the output end of the right motor and has a suction port S, a delivery port P, and a load sensing port LS. The suction port S is communicated with the fuel tank, the delivery port P is communicated with an oil delivery pipeline, and the load sensing port LS is communicated with a load sensing oil circuit;

[0009] And a brake valve block assembly, the brake valve block assembly includes a brake master cylinder, a five-way four-port valve, a spring and a brake. One end of the piston rod of the brake master cylinder is connected with a pedal, and the other end is connected to one end of the corresponding five-way four-port valve and communicates with the corresponding brake. The five-way four-port valve is provided with an upper oil port a, a left oil port b, a middle oil port c and a right oil port d, and has five working positions. The upper oil port a communicates with the corresponding brake, the left oil port b communicates with the fuel tank, the middle oil port c communicates with the load-sensitive oil circuit, and the right oil port d communicates with the oil pipeline. The five-way four-port valve can be moved to any working position to make the upper oil port a communicate with the left oil port b, each oil port does not communicate with each other, the upper oil port a communicates with the middle oil port c, the right oil port d communicates with the upper oil port a and the middle oil port c at the same time, or the right oil port d communicates with the upper oil port a. One end of the spring is fixedly connected to the other end of the corresponding five-way four-port valve away from the corresponding brake master cylinder, and the other end is fixedly installed.

[0010] The beneficial effects of the present invention are as follows: During use, when the user steps on the pedal to different depths, the five-way four-port valve moves to the corresponding working position, so that the five-way four-port valve communicates with the brake, the oil pipeline, the load-sensitive oil circuit and the fuel tank in different working positions, thereby realizing different multi-stage braking effects, and improving the technical problem that the braking of the existing new energy tractor becomes heavier and heavier as the horsepower demand increases, affecting the user experience.

[0011] On the basis of the above technical solutions, the present invention can be further improved as follows.

[0012] Further, pistons are fixedly connected to the middle ends of the piston rods of the two brake master cylinders, and left and right piston chambers are respectively formed at both ends of the piston. The left piston chamber and the right piston chamber are communicated through an oil return pipeline, and the left piston chamber also communicates with the corresponding brake.

[0013] Further, the oil return pipeline is communicated with a brake oil pot, and the brake oil pot is also communicated with the right piston chamber.

[0014] Further, the five working positions are arranged in sequence from far to near the brake master cylinder, and each working position is provided with an upper oil port a, a left oil port b, a middle oil port c and a right oil port d. In the first working position, the five-way four-port valve can be switched to make the upper oil port a communicate with the left oil port b. In the second working position, the upper oil port a, the left oil port b, the middle oil port c and the right oil port d do not communicate with each other. In the third working position, the five-way four-port valve can be switched to make the upper oil port a communicate with the middle oil port c. In the fourth working position, the five-way four-port valve can be switched to make the right oil port d communicate with the upper oil port a and the middle oil port c at the same time. In the fifth working position, the five-way four-port valve can be switched to make the right oil port d communicate with the upper oil port a.

[0015] Furthermore, the oil return pipeline includes a right pipeline, one end of the right pipeline is connected to the left piston chamber, and when the five-position four-way valve moves to the third, fourth and fifth working positions, one end of the right pipeline is blocked by the corresponding piston, and the other end of the right pipeline is simultaneously connected to the brake oil tank and the right piston chamber.

[0016] Furthermore, the return oil pipeline also includes a left pipeline, which is located on the side of the right pipeline away from the right piston chamber, and one end of the left pipeline is connected to the bottom of the left piston chamber, and the left pipeline is equipped with a right direction control valve, and the other end of the left pipeline is simultaneously connected to the brake oil tank and the right piston chamber.

[0017] Furthermore, a pipeline connecting the left piston chamber and the corresponding brake is provided with a left direction control valve, and an outlet of the left direction control valve and the pipeline connecting the corresponding brake are connected to the five-position four-way valve.

[0018] Furthermore, it also includes a left motor and a gear pump transmission-connected to the output end of the left motor, the oil inlet of the gear pump is connected to the oil tank, and the oil outlet is connected to the oil pipeline.

[0019] Furthermore, a filter is provided in the pipeline between the oil outlet of the gear pump and the oil delivery pipeline.

[0020] Furthermore, a pipeline between the oil outlet of the gear pump and the filter is connected to a relief valve, and the oil outlet of the relief valve is connected to the oil tank.

[0021] Furthermore, a pipeline between the filter and the oil delivery pipeline is provided with a left one-way valve, and an oil inlet of the left one-way valve is connected to an oil outlet of the filter.

[0022] Furthermore, the oil pipeline is connected to a pressure sensor.

[0023] Furthermore, the oil delivery pipeline is provided with a right one-way valve, and the oil inlet of the right one-way valve is connected to the oil delivery port P.

[0024] The present invention also provides a tractor, comprising the three-stage braking system of the new energy tractor. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic diagram of the present invention;

[0026] Figure 2 for Figure 1 The local structure diagram of

[0027] Figure 3 It is a schematic diagram of the five-position four-way valve of the present invention being located in the first working position, showing the state where the pedal is not stepped on and the right motor is started;

[0028] Figure 4 Schematic diagram of the five - way four - port valve of the present invention in the second working position, showing that the pedal starts to act and is in a state of short - term braking;

[0029] Figure 5 Schematic diagram of the five - way four - port valve of the present invention in the third working position, showing a state of relatively small braking pressure;

[0030] Figure 6 Schematic diagram of the five - way four - port valve of the present invention in the fourth working position, showing a state of relatively large braking pressure;

[0031] Figure 7 is Figure 6 partial structure diagram of

[0032] Figure 8 Schematic diagram of the five - way four - port valve of the present invention in the fourth working position, showing a state where the plunger pump fails and the gear pump starts;

[0033] Figure 9 Schematic diagram of the five - way four - port valve of the present invention in the fifth working position, showing a state where both the plunger pump and the gear pump fail.

[0034] In the attached drawings, the list of components represented by each reference numeral is as follows:

[0035] 1. Brake oil pot; 2. Right - hand direction control valve; 3. Left - hand direction control valve; 4. Pedal; 5. Right piston chamber; 6. Five - way four - port valve; 7. Left piston chamber; 8. Piston; 9. Spring; 10. Brake; 11. Brake valve block assembly; 12. Left motor; 13. Fuel tank; 14. Relief valve; 15. Filter; 16. Left check valve; 17. Right check valve; 18. Right motor; 19. Plunger pump; 20. Gear pump; 21. Pressure sensor. Detailed implementation mode

[0036] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0037] Example 1

[0038] As Figures 1-9 , the present invention provides a three - stage braking system for a new - energy tractor, including:

[0039] Fuel tank 13;

[0040] Right motor 18;

[0041] The plunger pump 19 is transmission-connected to the output end of the right motor 18 and has an oil suction port S, an oil delivery port P and a load sensing port LS. The oil suction port S is connected to the oil tank 13, the oil delivery port P is connected to the oil delivery pipeline, and the load sensing port LS is connected to the load sensing oil circuit.

[0042] And a brake valve block assembly 11, the brake valve block assembly 11 includes a brake master cylinder, a five-position four-way valve 6, a spring 9 and a brake 10, one end of the piston rod of the brake master cylinder is connected to a pedal 4, and the other end is connected to one end of the corresponding five-position four-way valve 6, and is connected to the corresponding brake 10, the five-position four-way valve 6 is provided with an upper oil port a, a left oil port b, a middle oil port c and a right oil port d, and has five working positions, the upper oil port a is connected to the corresponding brake 10, the left oil port b and The oil tank 13 is connected, the middle oil port c is connected to the load-sensitive oil circuit, the right oil port d is connected to the oil pipeline, the five-position four-way valve 6 can be moved to any working position to make the upper oil port a and the left oil port b connected, the oil ports are not connected to each other, the upper oil port a and the middle oil port c are connected, the right oil port d is connected to the upper oil port a and the middle oil port c at the same time, or the right oil port d is connected to the upper oil port a, one end of the spring 9 is fixedly connected to the other end of the corresponding five-position four-way valve 6 away from the corresponding brake master cylinder, and the other end is fixedly installed.

[0043] Specifically, the brake valve block assembly 11 is provided with two groups, and the two brakes 10 of the two groups of brake valve block assemblies 11 are respectively used to brake the running parts (such as tires or tracks) of the tractor. The plunger pump 19 is a conventional technical means in the art, and the present invention does not elaborate on its structure in detail.

[0044] Among them, both pedals 4 are provided with angle sensors, which monitor the angle of the driver's brake pedal in real time through the angle sensors, so as to judge the driver's braking intention, and convert the pedal angle information into electrical signals through the angle sensors, and transmit them to the vehicle's electronic control unit (ECU). The ECU accurately controls the braking pressure and optimizes the braking effect based on these signals in combination with other parameters such as vehicle speed and braking force.

[0045] In this embodiment, the left end of the piston rod of the brake master cylinder can be mechanically connected to one end of the corresponding five-position four-way valve 6 through a spring, so that when the user starts to apply force to the pedal 4, the elastic force of the spring needs to be overcome before the five-position four-way valve 6 can move and switch the working position, so as to provide initial resistance, prevent misoperation, and make the output of braking force smoother and more gradual, so that the driver can control the deceleration process of the tractor more accurately and avoid vehicle loss of control due to a sudden increase in braking force.

[0046] The beneficial effects of this embodiment are as follows: When in use, the user steps on the pedal 4 with different depths, causing the five-way four-position valve 6 to move to the corresponding working position, enabling the five-way four-position valve 6 to communicate with the brake 10, the oil pipeline, the load-sensitive oil circuit, and the fuel tank 13 at different working positions, thereby achieving different multi-stage braking effects and improving the technical problem that the braking of existing new energy tractors becomes heavier as the horsepower demand increases, affecting the user experience.

[0047] Specifically, after the engine starts, such as Figure 3 , the right motor 18 works. At this time, when the foot pedal 4 is not stepped on and the five-way four-position valve 6 is in the first working position, the angle sensor signal of the pedal 4 is 0. In this state, the brake 10 is connected to the fuel tank 13 through the upper oil port a and the left oil port b, and there is no braking.

[0048] When starting to step on the pedal 4, such as Figure 4 , overcoming the elastic force of the spring 9, the five-way four-position valve 6 displaces to the second working position. At this time, the upper oil port a, the left oil port b, the middle oil port c, and the right oil port d at the second working position of the five-way four-position valve 6 are in a state of being cut off from each other, and the oil of the brake 10 does not flow to the fuel tank 13. At this time, because the displacement is very small, it is still not in a braking state for a short time.

[0049] Continuing to step on the pedal 4, such as Figure 5 , overcoming the elastic force of the spring 9, the five-way four-position valve 6 displaces to the third working position. At this time, because the five-way four-position valve 6 switches to connect the upper oil port a and the middle oil port c, the brake master cylinder transmits the oil to the brake 10, and is connected to the load-sensitive oil circuit through the upper oil port a and the middle oil port c of the five-way four-position valve 6. The oil is transported to the plunger pump 19 through the load-sensitive oil circuit and the load-sensitive port LS. At this time, a small braking pressure is achieved using the oil in the brake master cylinder.

[0050] Continuing to step on the pedal 4, such as Figure 6 and Figure 7 , overcoming the elastic force of the spring 9, the five-way four-position valve 6 displaces to the fourth working position. The five-way four-position valve 6 switches so that the right oil port d is connected to both the upper oil port a and the middle oil port c at the same time. The oil output port P of the plunger pump 19 outputs oil, and forms a loop through the oil pipeline - right oil port d - middle oil port c - load-sensitive oil circuit connected to the load-sensitive port LS of the plunger pump 19. At the same time, part of the oil is transported to the brake 10 through the right oil port d - upper oil port a. At this time, a large pressure can be output for braking to brake the whole vehicle. Under normal circumstances, because the plunger pump 19 has a feedback force, the braking foot feeling is very strong.

[0051] After continuing to step on the pedal 4, the elastic force of the spring 9 is overcome. Since the five-way four-port valve 6 is displaced to the fifth working position, at this time, the five-way four-port valve 6 is switched so that the right oil port d is communicated with the upper oil port a, but the right oil port d and the middle oil port c are in a disconnected state, and a large pressure cannot be established. The feedback force of the plunger pump 19 will cause the five-way four-port valve 6 to return to the fourth working position to achieve balance.

[0052] Through the above control method, the user steps on the pedal 4 with different magnitudes of force, causing the five-way four-port valve 6 to be in the second working position, the third working position, and the fourth working position, realizing the sequential change of the braking force magnitude, and further realizing the effect of three-stage braking, improving the technical problem that the braking of the existing new energy tractor becomes heavier and heavier as the horsepower demand increases, affecting the user experience.

[0053] In this solution, during the braking process, when the plunger pump 19 fails, such as Figure 9 , stepping on the pedal 4 with great force, the five-way four-port valve 6 is displaced to the fifth working position, and the pressure of the brake master cylinder acts on the brake 10 to achieve emergency braking.

[0054] Embodiment 2

[0055] As Figure 1 and Figure 2 , on the basis of Embodiment 1, a piston 8 is fixedly connected to the middle end of the piston rod of the two brake master cylinders, and left and right piston chambers 7 and 5 are respectively formed at both ends of the piston 8. The left piston chamber 7 and the right piston chamber 5 are communicated through an oil return pipeline, and the left piston chamber 7 is also communicated with the corresponding brake 10.

[0056] The beneficial effect of adopting the preferred solution in the above embodiment is that when the user steps on the pedal 4, the piston 8 is driven by the piston rod to move, compressing the left piston chamber 7, and the right piston chamber 5 expands accordingly, so that part of the oil in the left piston chamber 7 can return to the right piston chamber 5 through the oil return pipeline, and part of the oil can enter the corresponding brake 10 through the pipeline to achieve braking.

[0057] Embodiment 3

[0058] As Figure 1 and Figure 2 , on the basis of Embodiments 1 and 2, the oil return pipeline is communicated with a brake oil pot 1, and the brake oil pot 1 is also communicated with the right piston chamber 5 at the same time.

[0059] The beneficial effect of adopting the preferred solution in the above embodiment is that when the left piston chamber 7 is compressed, part of the redundant oil in the left piston chamber 7 flows to the brake oil pot 1. At the same time, the brake oil pot 1 can also be used to supplement the oil in the left piston chamber 7 and the right piston chamber 5.

[0060] Embodiment 4

[0061] AsFigures 3-7 , on the basis of Embodiments 1-3, five working positions are arranged in sequence along the direction from far away to close to the master brake cylinder, and each working position is provided with an upper oil port a, a left oil port b, a middle oil port c and a right oil port d. When in the first working position, the five-way four-way valve 6 can be switched to connect the upper oil port a and the left oil port b. When in the second working position, the upper oil port a, the left oil port b, the middle oil port c and the right oil port d are not connected to each other. When in the third working position, the five-way four-way valve 6 can be switched to connect the upper oil port a and the middle oil port c. When in the fourth working position, the five-way four-way valve 6 can be switched so that the right oil port d is simultaneously connected to the upper oil port a and the middle oil port c. When in the fifth working position, the five-way four-way valve 6 can be switched to connect the right oil port d and the upper oil port a.

[0062] The beneficial effect of adopting the preferred scheme in the above embodiment is that when in use, the user steps on the pedal 4 to different depths, so that the five-way four-way valve 6 moves to the corresponding working position, and the five-way four-way valve 6 is connected to the brake 10, the oil pipeline, the load-sensitive oil circuit and the fuel tank 13 at different working positions, thereby realizing different multi-stage braking effects and improving the technical problem that the braking of the existing new energy tractor becomes heavier and heavier as the horsepower demand increases, which affects the user experience.

[0063] Embodiment 5

[0064] As Figures 3-7 , on the basis of Embodiments 1-4, the oil return pipeline includes a right pipeline, one end of the right pipeline is connected to the left piston chamber 7, and when the five-way four-way valve 6 moves to the third, fourth and fifth working positions, one end of the right pipeline is blocked by the corresponding piston 8, and the other end of the right pipeline is simultaneously connected to the brake oil pot 1 and the right piston chamber 5.

[0065] The beneficial effect of adopting the preferred scheme in the above embodiment is that when the five-way four-way valve 6 moves to the third, fourth or fifth working position, one end of the right pipeline is blocked by the corresponding piston 8, the left piston chamber 7 is compressed, and the excess oil in the left piston chamber 7 flows to the brake oil pot 1 and the right piston chamber 5.

[0066] Embodiment 6

[0067] As Figure 1 and Figure 2 , on the basis of Embodiments 1-5, the oil return pipeline further includes a left pipeline, the left pipeline is located on the left side of the right pipeline away from the right piston chamber 5, and one end of the left pipeline is connected to the bottom of the left piston chamber 7, and the left pipeline is provided with a right direction control valve 2, and the other end of the left pipeline is simultaneously connected to the brake oil pot 1 and the right piston chamber 5.

[0068] The beneficial effect of adopting the preferred scheme in the above embodiment is that when one end of the right pipeline is blocked by the corresponding piston 8, the excess oil in the left piston chamber 7 can flow to the right piston chamber 5 under the control of the right direction control valve 2.

[0069] Example 7

[0070] like Figures 1-9 On the basis of Examples 1-6, the pipeline connecting the left piston chamber 7 and the corresponding brake 10 is provided with a left direction control valve 3, and the outlet of the left direction control valve 3 and the pipeline connecting the corresponding brake 10 are connected to a five-position four-way valve 6.

[0071] The beneficial effect of adopting the preferred solution in the above embodiment is that, if the pedal 4 is continuously stepped on, Figure 5 , overcoming the elastic force of the spring 9, the five-position four-way valve 6 moves to the third working position. At this time, because the five-position four-way valve 6 is switched to the upper oil port a and the middle oil port c are connected, the oil in the left piston chamber 7 of the brake master cylinder is transferred to the brake 10 through the left direction control valve 3, and is connected to the load-sensitive oil circuit through the upper oil port a and the middle oil port c of the five-position four-way valve 6. The oil is delivered to the plunger pump 19 through the load-sensitive oil circuit and the load-sensitive port LS. At this time, the oil in the brake master cylinder is used to achieve a smaller braking pressure. The oil in the plunger pump 19 is discharged to the oil pipeline through the oil delivery port P.

[0072] Example 8

[0073] like Figure 8 On the basis of Examples 1-7, the three-stage braking system of a new energy tractor also includes a left motor 12 and a gear pump 20 connected to the output end of the left motor 12, the oil inlet of the gear pump 20 is connected to the oil tank 13, and the oil outlet is connected to the oil pipeline.

[0074] The beneficial effect of adopting the preferred solution in the above embodiment is that during the braking process, if Figure 8 If the plunger pump 19 suddenly fails, the left motor 12 starts to work and pumps oil into the brake system through the gear pump 20 for emergency braking to solve the problem of normal braking when the plunger pump 19 fails.

[0075] Based on the above embodiment, in this solution, during the braking process, when both the plunger pump 19 and the gear pump 20 fail, Figure 9 , step on the pedal 4 vigorously, the five-position four-way valve 6 moves to the fifth working position, the oil in the left piston chamber 7 of the brake master cylinder is output and acts on the brake 10, realizing emergency braking.

[0076] Example 9

[0077] like Figure 1 and Figure 2 On the basis of Embodiment 1-8, a filter 15 is provided in the pipeline between the oil outlet of the gear pump 20 and the oil delivery pipeline.

[0078] The beneficial effects of adopting the preferred solution in the above embodiments are that impurities and contaminants in the oil can be removed through the filter 15, preventing these impurities from entering the key equipment components of the hydraulic system, thereby reducing wear and damage and extending the service life of the equipment.

[0079] Embodiment 10

[0080] As Figure 1 and Figure 2 , on the basis of Embodiments 1 - 9, a pipeline between the oil outlet of the gear pump 20 and the filter 15 is connected to a relief valve 14, and the oil outlet of the relief valve 14 is connected to the oil tank 13.

[0081] The beneficial effects of adopting the preferred solution in the above embodiments are that when the system pressure exceeds the set value, the relief valve 14 is opened to guide the excess hydraulic oil back to the oil tank 13, thereby preventing the system pressure from being too high and ensuring the stability of the system pressure.

[0082] Embodiment 11

[0083] As Figure 1 and Figure 2 , on the basis of Embodiments 1 - 10, a left check valve 16 is arranged in the pipeline between the filter 15 and the oil pipeline, and the oil inlet of the left check valve 16 is connected to the oil outlet of the filter 15.

[0084] The beneficial effects of adopting the preferred solution in the above embodiments are that the oil flows unidirectionally from the filter 15 to the oil pipeline through the left check valve 16, preventing the reverse flow of the oil from damaging the filter 15 and the gear pump 20, preventing pressure fluctuations or system failures caused by the oil backflow, and maintaining the pressure in the system.

[0085] Embodiment 12

[0086] As Figure 1 and Figure 2 , on the basis of Embodiments 1 - 11, a pressure sensor 21 is connected to the oil pipeline.

[0087] The beneficial effects of adopting the preferred solution in the above embodiments are that the system pressure of the oil pipeline can be monitored in real time through the pressure sensor 21, so that when an abnormal situation is detected, the control unit can issue an alarm in time to remind the operator to take measures to avoid system failures or damages.

[0088] Embodiment 13

[0089] As Figure 1 and Figure 2 , on the basis of Embodiments 1 - 12, a right check valve 17 is arranged in the oil pipeline, and the oil inlet of the right check valve 17 is connected to the oil outlet P.

[0090] The beneficial effects of adopting the preferred solution in the above embodiments are as follows: the right one-way valve 17 enables the oil to flow unidirectionally from the plunger pump 19 to the oil pipeline, preventing the reverse flow of oil from damaging the plunger pump 19, preventing pressure fluctuations or system failures caused by oil backflow, and maintaining the pressure in the system.

[0091] Embodiment 14

[0092] The present invention also provides a tractor, including the new energy tractor three-stage braking system as described in Embodiments 1-13.

[0093] The beneficial effects of adopting the preferred solution in the above embodiments are as follows: by adopting this new energy tractor three-stage braking system, three-stage braking can be achieved, reducing the pedal force during the braking process of large horsepower, and improving the problem that normal braking cannot be achieved when the equipment fails.

[0094] Specifically, after the engine is started, as Figure 3 , the right motor 18 works. At this time, without stepping on the foot pedal 4, the angle sensor signal of the pedal 4 is 0, and the pressure value of the pressure sensor 21 is the standby pressure value of the plunger pump 19 (about 26 bar). At this time, the left motor 12 does not work, and the five-way four-position valve 6 is in the first working position. In this state, the brake 10 is connected to the fuel tank 13 through the upper oil port a and the left oil port b, and no braking is performed.

[0095] When starting to step on the pedal 4, as Figure 4 , overcoming the elastic force of the spring 9, the five-way four-position valve 6 displaces to the second working position. At this time, the upper oil port a, the left oil port b, the middle oil port c, and the right oil port d of the second working position of the five-way four-position valve 6 are in a state of being cut off from each other. The volume of the left piston chamber 7 becomes smaller, and the excess brake fluid flows to the brake oil pot 1. The volume of the right piston chamber 5 becomes larger, and the oil of the brake 10 does not lead to the fuel tank 13. At this time, because the movement amount is very small, it is still not in the braking state for a short time.

[0096] Continue to step on the pedal 4, as Figure 5 , overcoming the elastic force of the spring 9, the five-way four-position valve 6 displaces to the third working position. At this time, because the five-way four-position valve 6 switches to connect the upper oil port a and the middle oil port c, the right pipeline connected to the left piston chamber 7 of the brake master cylinder is blocked by the piston 8 and remains closed. The oil in the left piston chamber 7 is transmitted to the brake 10 through the left direction control valve 3, and is connected to the load-sensitive oil circuit through the upper oil port a and the middle oil port c of the five-way four-position valve 6. The oil is transported to the plunger pump 19 through the load-sensitive oil circuit and the load-sensitive port LS. At this time, a small braking pressure is achieved by using the oil in the brake master cylinder.

[0097] Continue to step on the pedal 4, as Figure 6 and Figure 7, overcome the elastic force of spring 9, the five-position four-way valve 6 moves to the fourth working position, the five-position four-way valve 6 switches to the right oil port d and is connected to the upper oil port a and the middle oil port c at the same time, the oil delivery port P of the plunger pump 19 outputs oil, through the oil delivery pipeline-right oil port d-middle oil port c-load sensitive oil circuit connected to the load sensitive port LS of the plunger pump 19, forming a loop, at the same time, part of the oil is delivered to the brake 10 through the right oil port d-upper oil port a, at this time, the brake can output a large pressure to brake the whole vehicle. Under normal circumstances, because the plunger pump 19 has feedback force, the brake foot feel is very strong.

[0098] After continuing to step on the pedal 4, the elastic force of the spring 9 is overcome, because the five-position four-way valve 6 moves to the fifth working position. At this time, the five-position four-way valve 6 is switched to the right oil port d and connected with the upper oil port a, but the right oil port d and the middle oil port c are disconnected, and a large pressure cannot be established. The feedback force of the plunger pump 19 will cause the five-position four-way valve 6 to return to the fourth working position to achieve balance.

[0099] During braking, if Figure 8 If the plunger pump 19 fails suddenly, the pedal 4 has a displacement signal, but the pressure sensor 21 has no pressure signal. The left motor 12 starts to work and pumps oil into the brake system through the gear pump 20 for emergency braking to solve the problem of normal braking when the plunger pump 19 fails.

[0100] During the braking process, when both the plunger pump 19 and the gear pump 20 fail, Figure 9 , step on the pedal 4 vigorously, the five-position four-way valve 6 moves to the fifth working position, the oil in the left piston chamber 7 of the brake master cylinder is output and acts on the brake 10, realizing emergency braking.

[0101] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0102] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0103] In the present invention, unless otherwise clearly specified or limited, the terms "mounted", "connected", "coupled", "fixed", etc. shall be construed broadly. For example, it may be a fixed connection, a detachable connection, or an integral one; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements, 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.

[0104] In the present invention, unless otherwise clearly specified or limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may mean that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0105] In the description of this specification, the description with reference to the terms "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 any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0106] Although the embodiments of the present invention have been shown and 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 three-stage braking system for a new energy tractor, characterized in that, Comprising: Fuel tank (13); Right motor (18); Plunger pump (19), drivingly connected to the output end of the right motor (18), and having a suction port S, a delivery port P, and a load sensing port LS, the suction port S communicating with the fuel tank (13), the delivery port P communicating with an oil delivery pipeline, and the load sensing port LS communicating with a load sensing oil circuit; And a brake valve block assembly (11), the brake valve block assembly (11) including a brake master cylinder, a five-way four-port valve (6), a spring (9), and a brake (10), one end of the piston rod of the brake master cylinder being connected to a pedal (4), and the other end being connected to one end of the corresponding five-way four-port valve (6) and communicating with the corresponding brake (10), the five-way four-port valve (6) being provided with an upper oil port a, a left oil port b, a middle oil port c, and a right oil port d, and having five working positions, the upper oil port a communicating with the corresponding brake (10), the left oil port b communicating with the fuel tank (13), the middle oil port c communicating with the load sensing oil circuit, the right oil port d communicating with the oil delivery pipeline, the five-way four-port valve (6) being movable to any working position to make the upper oil port a and the left oil port b communicate, all oil ports not communicating with each other, the upper oil port a and the middle oil port c communicate, the right oil port d communicate with both the upper oil port a and the middle oil port c simultaneously, or the right oil port d communicate with the upper oil port a, and one end of the spring (9) being fixedly connected to the other end of the corresponding five-way four-port valve (6) away from the corresponding brake master cylinder, and the other end being fixedly installed.

2. The three-stage braking system of a new energy tractor according to claim 1, wherein, A piston (8) is fixedly connected to the middle end of the piston rods of the two brake master cylinders, and left and right piston chambers (7, 5) are respectively formed at both ends of the piston (8), the left piston chamber (7) communicating with the right piston chamber (5) through an oil return pipeline, and the left piston chamber (7) also communicating with the corresponding brake (10).

3. The three-stage braking system of a new energy tractor according to claim 2, characterized in that, The oil return pipeline communicates with a brake oil pot (1), and the brake oil pot (1) also communicates with the right piston chamber (5) simultaneously.

4. The three-stage braking system of a new energy tractor according to claim 3, wherein, The five working positions are arranged in sequence in a direction away from and then close to the brake master cylinder, and each working position is provided with an upper oil port a, a left oil port b, a middle oil port c, and a right oil port d. In the first working position, the five-way four-port valve (6) can be switched to make the upper oil port a and the left oil port b communicate. In the second working position, the upper oil port a, the left oil port b, the middle oil port c, and the right oil port d do not communicate with each other. In the third working position, the five-way four-port valve (6) can be switched to make the upper oil port a and the middle oil port c communicate. In the fourth working position, the five-way four-port valve (6) can be switched to make the right oil port d communicate with both the upper oil port a and the middle oil port c simultaneously. In the fifth working position, the five-way four-port valve (6) can be switched to make the right oil port d communicate with the upper oil port a.

5. The three-stage braking system of a new energy tractor according to claim 4, wherein, The oil return pipeline includes a right pipeline, one end of the right pipeline communicating with the left piston chamber (7), and when the five-way four-port valve (6) moves to the third, fourth, and fifth working positions, one end of the right pipeline is blocked by the corresponding piston (8), and the other end of the right pipeline communicates with the brake oil pot (1) and the right piston chamber (5) simultaneously.

6. The three-stage braking system of a new energy tractor according to claim 5, characterized in that, The oil return pipeline also includes a left pipeline, which is located on the side of the right pipeline away from the right piston chamber (5), and one end of which is connected to the bottom of the left piston chamber (7). The left pipeline is provided with a right directional control valve (2), and the other end of the left pipeline is connected to both the brake oil tank (1) and the right piston chamber (5).

7. The three-stage braking system of a new energy tractor according to claim 2, wherein The pipeline connecting the left piston chamber (7) and the corresponding brake (10) is provided with a left directional control valve (3), and the outlet of the left directional control valve (3) and the pipeline connecting the corresponding brake (10) are connected to the five-position four-way valve (6).

8. The three-stage braking system of a new energy tractor according to any one of claims 1-7, characterized in that, It also comprises a left motor (12) and a gear pump (20) drivingly connected to the output end of the left motor (12), wherein the oil inlet of the gear pump (20) is connected to the oil tank (13), and the oil outlet is connected to the oil pipeline.

9. The three-stage braking system of a new energy tractor according to claim 8, characterized in that, A filter (15) is provided in the pipeline between the oil outlet of the gear pump (20) and the oil delivery pipeline.

10. The three-stage braking system of a new energy tractor according to claim 9, wherein, The pipeline between the oil outlet of the gear pump (20) and the filter (15) is connected to a relief valve (14), and the oil outlet of the relief valve (14) is connected to the oil tank (13).

11. The three-stage braking system of a new energy tractor according to claim 9, characterized in that, The pipeline between the filter (15) and the oil delivery pipeline is provided with a left one-way valve (16), and the oil inlet of the left one-way valve (16) is connected to the oil outlet of the filter (15).

12. The three-stage braking system of a new energy tractor according to claim 8, characterized in that, The oil delivery pipeline is connected to a pressure sensor (21).

13. The three-stage braking system of a new energy tractor according to claim 12, wherein, The oil delivery pipeline is provided with a right one-way valve (17), and the oil inlet of the right one-way valve (17) is connected to the oil delivery port P.

14. A tractor, characterized in that, It comprises a three-stage braking system for a new energy tractor as described in any one of claims 1-13.

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