A power reversing hydraulic system with redundant protection

Abstract

A power reversing hydraulic system with redundant protection includes a hydraulic oil source, a first reversing valve, a second reversing valve, a cut-off valve, a proportional valve, and a relief valve. The cut-off valve input is connected to the hydraulic oil source, and the output is respectively connected to the first reversing valve and the second reversing valve. The cut-off valve oil return port is connected to the oil tank; the first reversing valve and the second reversing valve input are connected in parallel, and the output is respectively connected to the clutch; the proportional valve oil inlet is connected to the hydraulic oil source, the oil outlet is connected to the relief valve, and the oil return port is connected to the oil tank. When one of the reversing valves fails, the cut-off valve is triggered to be powered on and closed, cutting off the hydraulic oil source from supplying oil to the reversing valve, so as to avoid the system being in a pressure-maintaining state in the event of a failure, causing a safety accident.

Description

Technical Field

[0001] The invention relates to the field of power reversing system safety, and in particular to a power reversing hydraulic system with redundant protection. Background Art

[0002] In the conventional tractor power reversing hydraulic oil circuit system, the hydraulic circuit is connected to the oil pump, oil tank, reversing valve, and clutch through the oil pipe. The power reversing handle outputs the CAN signal to the bus. The controller obtains the bus signal, controls the corresponding reversing valve solenoid to be energized, and the oil pump delivers hydraulic pressure to the hydraulic wet clutch. The engine power is transmitted to the forward gear or reverse gear in the gearbox, so that the vehicle can move forward or backward. When the reversing solenoid valve is stuck and fails, the neutral signal input through the handle and the electrical signal input by the electronic clutch pedal are both invalid. The reversing valve cannot respond to change the working position. The system is in a pressure-maintaining state, and the engine power is still output. At this time, when the brake disc is directly used to brake the wheel to stop, the brake will conflict with the engine power, damaging the transmission components. At the same time, the vehicle may lose control due to the solenoid valve failure and cannot stop, posing a serious safety hazard. Summary of the invention

[0003] The purpose of the present invention is to provide a power reversing hydraulic system with redundant protection, which can cut off the oil circuit in time to stop the vehicle and ensure the safety of vehicle driving when the reversing valve in the power reversing system fails and gets stuck.

[0004] Specifically, a power reversing hydraulic system with redundant protection includes a hydraulic oil source, a first reversing valve, a second reversing valve, a cut-off valve, a proportional valve, and a relief valve. The cut-off valve input end is connected to the hydraulic oil source, the output end is connected to the first reversing valve and the second reversing valve respectively, and the cut-off valve oil return port is connected to the oil tank; The input ends of the first reversing valve and the second reversing valve are connected in parallel, and the output ends are connected to the clutches respectively; The oil inlet of the proportional valve is connected to the hydraulic oil source, the oil outlet is connected to the overflow valve, and the oil return port is connected to the oil tank.

[0005] Furthermore, a hydraulic oil filter is provided on the main hydraulic oil circuit for transporting the hydraulic oil from the hydraulic oil source to the outside.

[0006] Furthermore, the first reversing valve and the second reversing valve are both two-position three-way solenoid valves.

[0007] Furthermore, the cut-off valve is a two-position three-way solenoid valve, which is normally in an open state, the solenoid is energized to shift the valve core, the oil inlet is closed, and the hydraulic oil source is cut off from supplying oil to the outside. An intermediate relay is provided at the outlet end of the cut-off valve.

[0008] Furthermore, a throttle valve is provided between the oil outlet of the cut-off valve and the main oil circuit between the first reversing valve and the second reversing valve.

[0009] Furthermore, a throttle valve is provided at the oil inlet and the oil return port of the proportional valve, and an overflow valve is provided between the proportional valve and the overflow valve.

[0010] The present invention has at least the following beneficial effects: Improve system safety and reliability: By setting up a cut-off valve to form a redundant structure in the hydraulic system, when one of the reversing valves fails, the cut-off valve is triggered to close, cutting off the hydraulic oil supply to the reversing valve. At the same time, the excess oil in the system is unloaded through the cut-off valve, avoiding the system being in a pressure-maintaining state in the event of a failure, preventing the vehicle from being unable to stop and causing a safety accident.

[0011] Optimize system control accuracy: The proportional valve can accurately adjust the flow and pressure according to the input signal. Combined with the throttle valve set between it and each reversing valve, it can more accurately control the flow direction and flow of the hydraulic oil, thereby achieving precise control of the hydraulic wet clutch and improving work quality and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 , is the schematic diagram of the power reversing hydraulic system with redundant protection; Figure numerals: 4 - first reversing valve, 5 - second reversing valve, 9 - cut-off valve, 8 - overflow valve, 7 - proportional valve, 6 - hydraulic oil source.

[0013] In order to make the technical solutions and advantages of the present invention clearer, the following will be combined with the accompanying drawings to clearly and completely describe the implementation methods of the present invention. Obviously, the described embodiments are only some embodiments of the present invention. Based on the described embodiments, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0014] The words "first", "second" and similar words used in the present application specification and claims do not indicate any order, quantity or importance, but are only used to distinguish the relationship between multiple identical elements. The terms "connected" and "connected" in the present invention should be understood in a broad sense.

[0015] Combined with the attached drawings, the power reversing hydraulic system with redundant protection includes a hydraulic oil source 6, a first reversing valve 4, a second reversing valve 5, a cut-off valve 9, a proportional valve 7, and a relief valve 8. The input end of the cut-off valve 9 is connected to the hydraulic oil source 6, the output end is connected to the input end of the first reversing valve 4 and the second reversing valve 5, and the oil return port is connected to the oil tank. The input ends of the first reversing valve and the second reversing valve are connected in parallel, and the output ends F and R are respectively connected to the two-way wet clutch. The combination of the clutch and the power source enables the vehicle to move forward or backward; the oil return port of the first reversing valve and the oil return port of the second reversing valve are connected to the T1 / T2 port. When the reversing valve is separated from the clutch, the hydraulic oil returns to the oil tank through T1 / T2. The oil inlet P of the proportional valve 7 is connected to the hydraulic oil source, the oil outlet A is connected to the lower cavity of the relief valve 8, and the oil return port T is connected to the oil tank. The input end A of the relief valve 8 is connected to the output end of the cut-off valve 9, and the output end B is connected to the oil return port T4. Preferably, the working pressure of the relief valve is 2.1 MPa. The oil in ports T3, T4, and T1 / T2 all return to the oil tank.

[0016] A hydraulic oil filter is also provided on the hydraulic main oil line where the hydraulic oil is transported outward from the hydraulic source to filter out impurities in the medium. The clean hydraulic oil flows into the hydraulic system, reducing wear on hydraulic components and preventing blockage of the hydraulic system.

[0017] A throttle valve is provided between the oil outlet of the cut-off valve 9 and the main oil circuit between the first reversing valve 4 and the second reversing valve 5. A throttle valve is provided at the oil inlet P and the oil return port T of the proportional valve 7, and an overflow valve is provided between the oil outlet A and the overflow valve.

[0018] The first reversing valve and the second reversing valve are both two-position three-way solenoid valves, which are connected to the two ends of a two-way wet clutch and are used to control the forward and reverse movement of the vehicle respectively. The first reversing valve and the second reversing valve are closed in normal conditions and cannot be energized at the same time. They work independently of each other. When one of the reversing valves is energized and works, it is connected to the corresponding clutch hydraulic circuit to control the forward or reverse movement of the vehicle.

[0019] The shut-off valve is a two-position three-way solenoid valve, which is normally in the open state. When the solenoid valves in the hydraulic system are not energized, the oil in the hydraulic oil source can flow from the input and output ports of the shut-off valve 9 to the port of the relief valve. When the system pressure rises to the working pressure of the relief valve, the valve core moves down and the hydraulic oil returns to the T4 port.

[0020] An intermediate relay is set at the outlet of the cut-off valve. When the directional valve fails and gets stuck, the reversing valve cannot respond to the controller's command to switch the working position, and the system is in a pressure-maintaining state. At this time, the redundant protection is activated, triggering the intermediate relay to be energized, and the solenoid of the cut-off valve is energized to move the valve core. The cut-off valve works in the left position, and the cut-off valve ports 1 and 2 are connected, and port 3 is blocked. The oil path of the hydraulic oil flowing through the cut-off valve is cut off. At the same time, the oil in the system is unloaded through ports 1 and 2 of the cut-off valve, and the hydraulic oil flows to ports T1 / T2 to return to the oil tank, avoiding the system from being in a pressure-maintaining state in the event of a fault, causing a safety accident. When the relay loses power, the redundant protection circuit is disconnected, and the switch valve returns to the normal open state, which will not cause irreversible effects on the power reversing system.

[0021] Combined with the attached figure, when the reversing handle inputs the F gear signal, the proportional valve 7 is energized, the first reversing valve 4 is energized and works in the left position, ports 2 and 3 are open, and port 1 is blocked, the cut-off valve 9 is in the normally open state, the hydraulic oil flows through the proportional valve P port, and flows from port A through the lower chamber of the relief valve 8, pushing the valve core upward, and the relief valve is disconnected. The hydraulic oil flows through ports 3 and 2 of the cut-off valve to ports 3 and 2 of the first reversing valve to F, and the F end is connected to the forward clutch, the clutch and the power source are gradually combined, and the vehicle obtains forward power. The reversing handle inputs the N gear signal, the first reversing valve loses power and works in the right position, and the hydraulic oil flows from ports 2 and 1 of the reversing valve to the T1 / T return tank.

[0022] Similarly, when the reversing handle inputs the R gear signal, the proportional valve 7 is energized, the second reversing valve 5 is energized and works in the left position, ports 2 and 3 are open and port 1 is blocked, the cut-off valve 9 is in the normally open state, and the hydraulic oil flows from the cut-off valve 9 and the second reversing valve 5 to the R end, and the R end is connected to the reverse clutch. The clutch and the power source are gradually combined, and the vehicle obtains reverse power.

[0023] Combined with the attached drawings, the first reversing valve stuck fault is used as an example for explanation. The first reversing valve cannot respond to the controller command to close the valve group, the hydraulic oil source is still supplying oil to the reversing valve, the system is in a pressure-maintaining state, and the vehicle cannot stop, which may cause a safety accident. At this time, the redundant protection is activated, the intermediate relay is triggered to be energized, the solenoid of the cut-off valve is energized, the valve core moves, the cut-off valve works in the left position, the cut-off valve ports 1 and 2 are connected, and port 3 is blocked. The oil path of the hydraulic oil flowing through the cut-off valve is cut off, and at the same time, the oil in the system is unloaded through ports 1 and 2 of the cut-off valve, and the hydraulic oil flows to ports T1 / T2 to return to the oil tank, so as to avoid the system being in a pressure-maintaining state in the event of a fault, and the vehicle cannot stop and cause a safety accident. When the relay loses power, the redundant protection circuit is disconnected, and the switch valve returns to the normal open state, which will not cause irreversible effects on the power reversing system.

[0024] The hydraulic system of the present invention forms a redundant protection structure by adding a cut-off valve, thereby realizing the integration of the tractor with safety protection on the basis of the original standard power reversing system, improving the reliability and safety of the entire power reversing system, and being able to effectively solve the problem of being unable to park due to the jamming of the solenoid valve in the power reversing system, thereby greatly ensuring the safety of the vehicle during operation, reducing the risk of accidents, and having broad application prospects and practical value.

Claims

1. A power reversing hydraulic system with redundant protection, characterized in that: It includes a hydraulic oil source, a first reversing valve, a second reversing valve, a cut-off valve, a proportional valve, and a relief valve. The cut-off valve input end is connected to the hydraulic oil source, the output end is connected to the first reversing valve and the second reversing valve respectively, and the cut-off valve oil return port is connected to the oil tank; The input ends of the first reversing valve and the second reversing valve are connected in parallel, and the output ends are connected to the clutches respectively; The oil inlet of the proportional valve is connected to the hydraulic oil source, the oil outlet is connected to the lower cavity of the overflow valve, and the oil return port is connected to the oil tank.

2. The power reversing hydraulic system with redundant protection according to claim 1, characterized in that: A hydraulic oil filter is also provided on the main hydraulic oil line for transporting the hydraulic oil from the hydraulic oil source to the outside.

3. The power reversing hydraulic system with redundant protection according to claim 1, characterized in that: The first reversing valve and the second reversing valve are both two-position three-way solenoid valves.

4. The power reversing hydraulic system with redundant protection according to claim 1, characterized in that: The shut-off valve is a two-position three-way solenoid valve, which is normally open.

5. The power reversing hydraulic system with redundant protection according to claim 1, characterized in that: An intermediate relay is arranged at the outlet end of the cut-off valve.

6. The power reversing hydraulic system with redundant protection according to claim 1, characterized in that: A throttle valve is arranged at the oil outlet end of the cut-off valve.

7. The power reversing hydraulic system with redundant protection according to claim 1, characterized in that: The oil inlet, oil outlet and oil return port of the proportional valve are provided with throttle valves.

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