Tractor power reversing hydraulic system
By designing a tractor power reversing hydraulic system including a cut-off valve, an overflow valve and a check valve, the safety hazards and insufficient control accuracy in the power reversing process in traditional systems are solved, and safer, more efficient and accurate power reversing control is achieved.
Patent Information
- Application Number
- CN202411984590.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-04-01
AI Technical Summary
Traditional tractor hydraulic systems have safety hazards and insufficient control accuracy during power reversing, especially because the vehicle cannot stop normally due to the failure of the proportional pressure reducing valve.
A tractor power reversing hydraulic system is designed including at least two sets of proportional pressure reducing valves, cut-off valves, relief valves and check valves. Through the electromagnetic control of the cut-off valve, the hydraulic oil source is cut off in time to prevent parking safety hazards caused by the stagnation of the proportional pressure reducing valve. At the same time, the relief valve and the check valve work together to ensure the stability of the system pressure.
A safer, more efficient and precisely controlled power reversing process is achieved, avoiding parking safety hazards caused by the stagnation of proportional valve sets, and improving the pressure stability of the hydraulic system and the control of the oil return direction.
Smart Images
Figure CN119737356A_ABST
Abstract
Description
Technical Field
[0002] The invention relates to the field of tractor hydraulic systems, and in particular to a tractor power reversing hydraulic system. Background Art
[0003] During the operation of a tractor, the reliability and safety of power reversing are extremely important. Traditional hydraulic systems may have safety hazards such as the vehicle being unable to park normally due to a proportional pressure reducing valve failure, and are insufficient in the accuracy and flexibility of power distribution and control. The present invention aims to overcome these defects and provide a safer, more efficient and precisely controlled tractor power reversing hydraulic system. Summary of the invention
[0004] The tractor power reversing hydraulic system of the present invention comprises at least two groups of proportional pressure reducing valves and cut-off valves, wherein the cut-off valve input end is connected to a hydraulic oil source, the output end is connected to a proportional valve pressure reducing valve group, and the oil return end is connected to an oil tank; the input ends of the two groups of proportional pressure reducing valve groups are connected in parallel and connected to the cut-off valves, the output ends are respectively connected to hydraulic wet clutches, and the oil return end is connected to an oil tank.
[0005] Furthermore, the tractor power reversing hydraulic system also includes a relief valve, whose input end is connected to the hydraulic oil source and whose output end is connected to the oil return line, for controlling the system pressure to prevent excessive pressure and ensuring that the hydraulic actuator has sufficient pressure.
[0006] In one embodiment, the hydraulic system further comprises a one-way valve, the input end of which is connected to the output end of the overflow valve, and the output end of which is connected to the oil return line. When the radiator of the main oil return line is blocked, oil will flow into the oil tank from the outlet of the one-way valve.
[0007] Furthermore, the cut-off valve is a two-position three-way solenoid valve, which is normally in an open state and is connected to an intermediate relay. When the proportional pressure reducing valve is stuck and cannot be closed, the oil output is promptly cut off through the cut-off valve.
[0008] Furthermore, a group of proportional pressure reducing valves may be included, which is connected in parallel with the two groups of proportional pressure reducing valves, and the output end of which is connected to the PTO power output shaft for controlling the power of the PTO.
[0009] Furthermore, the proportional pressure reducing valve is a two-position three-way proportional pressure reducing valve.
[0010] The two sets of proportional pressure reducing valves in the tractor power reversing system are connected to the two ends of the two-way wet clutch respectively. The clutch and the power source are connected and separated by changing the working position of the proportional pressure reducing valve, thereby realizing the forward or reverse drive of the vehicle. The opening of the valve core is controlled by adjusting the current of the proportional pressure reducing valve, and the flow rate is accurately adjusted to make the vehicle shifting and reversing process smoother.
[0011] When one of the proportional pressure reducing valves is blocked or stuck, the trigger relay is energized and closed, closing the cut-off valve, promptly cutting off the hydraulic oil source to the proportional pressure reducing valve group, separating the hydraulic actuator clutch from the engine, and preventing the vehicle from being unable to stop due to the stuck proportional valve group, eliminating safety hazards. The relief valve and the one-way valve work together throughout the process to ensure that the system pressure is stable within the appropriate range and that the oil flows back in the predetermined direction. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 , is the schematic diagram of the power reversing hydraulic system.
[0013] 1.1-first proportional pressure reducing valve, 1.2-second proportional pressure reducing valve, 1.3-third proportional pressure reducing valve, 4-cut-off valve, 2-relief valve, 3-check valve. DETAILED DESCRIPTION
[0014] 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.
[0015] The terms "connected", "connected" and the like in the present invention should be understood in a broad sense.
[0016] Combination Figure 1 The cut-off valve 4 is normally open, the input end is connected to the hydraulic oil source P end, the output end is connected to the oil inlet P end of the first proportional pressure reducing valve and the second proportional pressure reducing valve, and the return oil end is connected to the oil return port T5 and returns to the oil tank. The output ends of the first proportional pressure reducing valve 1.1 and the second proportional pressure reducing valve 1.2 are respectively connected to the two ends of the two-way wet clutch to control the forward and backward movement of the tractor respectively, and the return oil end T is connected to the oil return port T3 and returns to the oil tank.
[0017] The two sets of proportional pressure reducing valves are two-position three-way electromagnetic reversing valves, which are respectively connected to the two ends of the two-way wet clutch. The first proportional pressure reducing valve 1.1 and the second proportional pressure reducing valve 1.2 cannot work at the same time. By changing the working position of one set of proportional pressure reducing valves, the clutch and the power source are combined and separated, so that the vehicle can move forward, stop or move backward. By adjusting the current of the proportional pressure reducing valve to control the opening of the valve core, the flow rate is accurately adjusted to make the vehicle shifting and reversing process smoother. It is used for PTO power control.
[0018] In one embodiment, the hydraulic system further comprises a third proportional pressure reducing valve 1.3, which is connected in parallel with the two sets of proportional pressure reducing valves, and the output end of which can be connected to the PTO power output shaft for connecting and disconnecting the PTO power.
[0019] In actual production and installation, the hydraulic system also includes a relief valve 2, whose input end is connected to the hydraulic oil source P and whose output end is connected to the main oil return port T1, which is used to control the system pressure to prevent the pressure from being too high and to ensure that the hydraulic actuator has sufficient pressure. A radiator is also connected to the main oil return port to prevent the oil temperature from being too high, which will cause the viscosity of the hydraulic oil to decrease, oxidize and deteriorate, and cause system pressure loss, thereby improving work efficiency.
[0020] The hydraulic system also includes a one-way valve 3, whose input end A is connected to the output end of the relief valve 2, and whose output end B is connected to the oil return circuit T2. When the radiator of the main oil return circuit is blocked, the oil pressure flowing through the A end of the one-way valve reaches the opening pressure, the valve core is pushed open, and the oil flows out from the B port to the return oil port T2 and returns to the oil tank from the oil outlet of the one-way valve.
[0021] In the present hydraulic system, the shut-off valve 4 can be connected to the intermediate relay. The shut-off valve is in an open state under normal circumstances. When one group of proportional pressure reducing valves is blocked or stuck, and the valve core cannot return to the initial position, the relay is triggered to be energized and closed, so that the shut-off valve is energized to connect ports 2 and 1, and port 3 is closed, and the hydraulic oil source is promptly cut off from the output to the proportional pressure reducing valve group. The system loses pressure maintenance, and the hydraulic oil returns from ports 2 and 1 of the shut-off valve to port T5 to the oil return tank. The clutch is separated from the engine power to avoid the vehicle being unable to stop due to the sticking of the proportional valve group, which brings serious safety hazards.
[0022] When the system is operating normally, one group of proportional pressure reducing valves, such as the forward proportional pressure reducing valve 1.1, is energized and works in the right position, the P and A ports are connected, and the T port is blocked. The oil at the P end of the hydraulic oil source flows to the P and A ends of the forward proportional pressure reducing valve 1.1 through the cut-off valve 4, and the hydraulic wet clutch is combined with the power source. The forward gear in the gearbox drives the vehicle forward to achieve power transmission. The controller controls the displacement of the valve core by outputting the current flowing through the proportional valve group according to the received command, and accurately adjusts the flow to make the vehicle start or shift process smoother. When parking is required, the forward proportional hydraulic valve 1.1 loses power, the valve core returns to the initial position, works in the left position, the A and T ports are connected, and the P port is blocked. The hydraulic oil returns from the T port to the T3 port to the oil tank.
[0023] Similarly, when the reverse proportional pressure reducing valve 1.2 is energized, it works in the right position, and the hydraulic oil flows through the cut-off valve to the P and A ports of the reverse proportional pressure reducing valve. The other end of the hydraulic wet clutch is combined with the power source, and the reverse gear in the gearbox drives the vehicle to move backward. When parking, the reverse proportional hydraulic valve 1.2 loses power and works in the left position, the A and T ports are open, and the P port is blocked, and the hydraulic oil returns from the T port to the T3 port to the oil tank.
[0024] In the present invention, two groups of proportional pressure reducing valves are respectively connected to the two ends of the two-way wet clutch, and the engagement of the clutch drives the vehicle forward or backward respectively. The cut-off valve is arranged at the main oil passage of the hydraulic system, and is in an open state under normal conditions. If one group of proportional pressure reducing valves is blocked or stuck, the valve core cannot return to the initial position, and the hydraulic system is always supplying oil to the outside, the cut-off valve is powered and closed at this time, and the hydraulic oil source is promptly cut off from the output to the proportional pressure reducing valve group, the system loses pressure and returns oil, and the clutch is separated from the engine power source, so as to avoid the vehicle being unable to stop due to the stuck proportional valve group, which brings serious safety hazards.
Claims
1. A tractor power reversing hydraulic system, characterized in that: It includes at least two groups of proportional pressure reducing valves and cut-off valves, wherein the cut-off valve input end is connected to the hydraulic oil source, the output end is connected to the proportional valve pressure reducing valve group, and the oil return end is connected to the oil tank; The input ends of the two proportional pressure reducing valve groups are connected in parallel and connected to the cut-off valve, the output ends are respectively connected to the hydraulic wet clutches, and the oil return ends are connected to the oil tank.
2. The tractor power reversing hydraulic system according to claim 1, characterized in that: It also includes a relief valve, the input end of which is connected to the hydraulic oil source, and the output end of which is connected to the main oil return line.
3. The tractor power reversing hydraulic system according to claim 2, characterized in that: It also includes a one-way valve, the input end of which is connected to the output end of the overflow valve, and the output end is connected to the oil return line.
4. The tractor power reversing hydraulic system according to claim 1, characterized in that: The cut-off valve is a two-position three-way solenoid valve, which is normally in an open state.
5. The tractor power reversing hydraulic system according to claim 1, characterized in that: The cut-off valve is connected to an intermediate relay.
6. The tractor power reversing hydraulic system according to claim 1, characterized in that: It also includes a set of proportional pressure reducing valves, which are connected in parallel with the two sets of proportional pressure reducing valves, and the output end is connected to the PTO.
7. The tractor power reversing hydraulic system according to claim 1 or 6, characterized in that: The proportional pressure reducing valve is a two-position three-way proportional pressure reducing valve.