Power switching 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 end is connected to the hydraulic oil source, and the output end 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 ends are connected in parallel, and the output ends are 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. The proportional valve accurately adjusts the flow and pressure to achieve precise control of the clutch. The cut-off valve forms a redundant structure in the hydraulic system. When the system fails, the cut-off valve is triggered to be powered on and the hydraulic oil source is cut off to supply oil to the reversing valve, so as to avoid the vehicle being unable to stop in the event of a system failure, causing a safety accident.

Description

Technical Field

[0001] The present invention relates to the field of power reversing system safety, and in particular to a power reversing system with redundant protection, which aims to solve the problem that a vehicle cannot stop due to a solenoid valve being stuck. Background Art

[0002] In conventional tractor power reversing control systems, the reversing handle outputs a CAN signal, and the controller obtains the forward, reverse, and neutral shift signals based on this signal to control the solenoid valve. The solenoid valve then controls the oil circuit to achieve the engagement and disengagement of the clutch and the engine flywheel. However, in the event of emergency braking or when the vehicle needs to stop immediately, when the solenoid valve fails due to a malfunction such as a jam and cannot be closed, or when the controller cannot respond to the input command to change the solenoid valve working position, the clutch is still in the engaged state, and the engine power is still output to the gearbox. At this time, when the emergency brake is applied, the brake disc will confront the engine power, causing the vehicle to shake, stall, and stall, and placing a large load on the gearbox, drive shaft and other components, damaging the transmission components. At the same time, the vehicle may lose control due to a solenoid valve failure and be unable to stop, posing a serious safety hazard. Summary of the invention

[0003] The object of the present invention is to provide a power reversing system with redundant protection, which can cut off the oil circuit in time to disengage the clutch and ensure safe parking of the vehicle when a reversing valve in the power reversing system fails and gets stuck or the controller does not respond to the output command.

[0004] Specifically, the power reversing system with redundant protection includes a switch valve, an intermediate relay, and an electronic clutch pedal. The switch valve is connected to the oil circuit between the oil pump and the reversing valve of the power reversing system and is normally in an open state. The switch valve is electrically connected to an intermediate relay; and the intermediate relay is electrically connected to an electronic clutch pedal.

[0005] Preferably, the working voltage of the intermediate relay is 4.5-5 V DC. When the clutch pedal is rotated to the maximum angle, a 4.5-5 V voltage signal is output.

[0006] The working process of the power reversing system with redundant protection is: when the power reversing main control system fails, the driver steps on the electronic clutch pedal to the maximum angle range, outputs the maximum current / voltage signal, triggers the normally open intermediate relay to close, and the switch valve is energized to close the oil inlet of the main control system, cutting off the oil pump from supplying oil to the outside. At the same time, the oil in the hydraulic circuit returns to the fuel tank through the oil return port of the switch valve.

[0007] In normal operation, the reversing solenoid valve controls the oil circuit according to the controller signal, and the switch valve is in a normally open state, which does not affect the normal operation of the system. When the reversing solenoid valve is stuck and / or the controller fails to output instructions, the 4.5~5V signal output by the clutch pedal causes the DC intermediate relay to be energized and closed, and the switch valve is energized and closed, cutting off the oil circuit output, thereby disengaging the clutch.

[0008] The present invention has at least the following beneficial effects: Enhanced reliability: When the solenoid valve or controller in the power reversing system fails, the redundant protection device can respond quickly, cut off the oil circuit in time to disengage the clutch, stop the vehicle normally, ensure the smooth and safe operation of the vehicle, and reduce the mechanical wear of the transmission system.

[0009] Simple and reliable structure: Through the coordinated work of the electronic clutch pedal, intermediate relay and switch valve, a reliable redundant protection mechanism is formed, which enables the tractor to integrate safety protection on the basis of the original standard power reversing system, thereby improving the reliability of the entire power reversing system.

[0010] 3. No impact on normal operation: Under normal working conditions, the switch valve is in a normally open state, which will not cause any interference or impact on the normal operation of the power reversing system, ensuring the normal driving and operation of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] 1- oil pump, 2- reversing valve, 3- clutch, 4- controller, 5- electronic clutch pedal, 6- reversing handle, 8- intermediate relay, 9- switch valve; Figure 1 , is the principle block diagram of the existing power switching system; Figure 2 , which is the principle block diagram of the power switching system with redundant protection. DETAILED DESCRIPTION

[0012] 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. In this application, only one group of reversing valves is given for example. In practical applications, several groups of reversing valves can be arranged in parallel according to needs. 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.

[0013] The terms "connected", "connected" and the like in the present invention should be understood in a broad sense.

[0014] Combined with Figure 1, a standard tractor power reversing system (only one set of reversing valves is given as an example), the hydraulic circuit includes an oil pump 1, an oil tank, a reversing valve 2, and a clutch 3, and is connected through a hydraulic oil pipe; the power reversing handle 6 outputs a CAN signal to the bus, the controller 4 obtains the bus signal, and controls the forward or reverse reversing valve solenoid to be energized, the oil pump oil delivers hydraulic pressure to the hydraulic wet clutch 3, the clutch is combined with the power source, and the forward gear or reverse gear is connected, so that the vehicle can move forward or backward. When the vehicle needs to stop, the handle inputs the N gear signal or the electronic clutch pedal is stepped on, and the clutch separation signal is input to the controller 4. The controller controls the reversing valve 2 to change the working position, cuts off the hydraulic oil output, and the clutch 3 is separated from the engine flywheel. When the controller 4 fails and / or the reversing solenoid valve 2 is stuck, the N gear signal input through the handle and the 0-5V voltage signal input by the electronic clutch pedal are both invalid, the controller 4 cannot respond to the input command, the reversing valve cannot switch the working position, and the system is in a pressure-maintaining state, causing the vehicle to be unable to stop, which brings serious safety hazards.

[0015] Combined with Figure 2 The power reversing system with redundant protection adds a redundant protection circuit based on the original standard power reversing system of the tractor, including a switch valve 9, an intermediate relay 8, and an electronic clutch pedal 5. The switch valve 9 is connected to the oil circuit between the oil pump 1 and the reversing valve 2 of the power reversing system. It is normally open and will not cause any interference or impact on the normal operation of the power reversing system. The forward or reverse reversing valve is connected to the clutch, which is a wet two-way clutch. The two directions can be connected to the forward reversing valve and the reverse reversing valve respectively. The switch valve is normally connected to the reversing valve, the switch valve is electrically connected to the intermediate relay, and the intermediate relay is electrically connected to the electronic clutch pedal. Preferably, the working voltage of the intermediate relay is DC5V.

[0016] When the controller 4 fails, the neutral signal input through the handle and the 0-5V voltage signal input through the electronic clutch pedal are both invalid, and the controller cannot respond to the corresponding reversing valve action. At this time, the driver immediately steps on the clutch pedal to the bottom, that is, at the maximum angle of the clutch pedal, and outputs a 5V voltage signal. The intermediate relay is energized, the redundant protection is started, the switch valve is closed, and the oil pump oil outlet circuit is cut off through the switch valve. The excess oil in the system returns to the tank through the switch, and the clutch is separated from the power source to stop the vehicle, so as to avoid the vehicle from losing control due to the controller or solenoid valve stuck in an emergency, which brings safety hazards. After the safety protection is started, release the pedal, the relay loses power, the redundant protection circuit is disconnected, and the switch valve returns to the normal open state. It returns to the initial state without manual maintenance, and will not cause irreversible effects on the power reversing system.

[0017] During normal operation of the reversing valve, the clutch can also be separated by inputting an electrical signal through the electronic clutch pedal 5. During normal braking, the 0-5V signal input by the pedal is sent to the controller 4, and the controller can normally control the gradual separation of the clutch. During emergency braking, the pedal is stepped on to the bottom, and the input 5V signal starts the redundant protection circuit, the intermediate relay is energized and closed, the switch valve is energized and closed from the normally open state, and the hydraulic oil pump is cut off from supplying oil to the outside. At the same time, the excess oil in the system returns to the oil tank through the switch valve, and the system loses the pressure-maintaining state, and the wheels are stopped in combination with the brake disc. Release the pedal, the intermediate relay loses power and disconnects, and the switch valve loses power and returns to the normally open state. The activation of the redundant protection circuit is reversible and does not affect the original system function.

[0018] The present invention forms a reliable redundant protection mechanism through the coordinated work of the electronic clutch pedal, the intermediate relay and the switch valve, realizes the integration of the tractor with the safety protection on the basis of the original standard power reversing system, improves the reliability of the entire power reversing system, can effectively solve the problem of being unable to park due to the jamming of the controller or the solenoid valve in the power reversing system, reduces vehicle wear and reduces the risk of accidents, and has broad application prospects and practical value.

Claims

1. A power switching system with redundant protection, characterized in that: Including switch valve, intermediate relay, electronic clutch pedal, The switch valve is connected to the oil circuit between the oil pump and the reversing valve of the power reversing system, and is normally in an open state; The switch valve is electrically connected to an intermediate relay; and the intermediate relay is electrically connected to an electronic clutch pedal.

2. When the electronic clutch pedal is stepped on to the maximum angle range, the maximum current / voltage signal is output, which triggers the normally open intermediate relay to close. The switch valve is energized, the oil inlet of the main control system is closed, and the oil pump is cut off from supplying oil to the outside.

3. The power switching system with redundant protection according to claim 1, characterized in that: The switch valve is a two-position three-way solenoid valve.

4. The power switching system with redundant protection according to claim 1, characterized in that: The working voltage of the intermediate relay is DC 4.5~5V.

5. The power switching system with redundant protection according to claim 1, characterized in that: When the clutch pedal is rotated to the maximum angle, a 4.5~5V voltage signal is output.

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