Hydraulic gear shift control system with limp-home function and working method thereof

Abstract

The present application belongs to the field of vehicle power transmission, and particularly relates to a hydraulic gear shifting control system with a limp-home function and a working method thereof. The present application comprises an oil supply circuit, which is connected with a cooling and lubricating module, a gear shifting module, a steering module, a parking module and a manual limp-home valve. The manual limp-home valve is in communication with the gear shifting module and the parking module respectively. The gear shifting module comprises a clutch module and a brake module. The gear shifting module, the steering module and the parking module can realize high-low gear shifting, and the switching of a highway transportation mode, a straight-ahead operation mode and a steering operation mode. The manual limp-home valve, in cooperation with the gear shifting module and the parking module, can realize a limp-home function, thereby avoiding serious safety accidents such as collision or rollover caused by emergency parking of a faulty vehicle.

Description

Technical Field

[0001] This invention belongs to the field of vehicle power transmission, specifically relating to a hydraulic shift control system with limp-off function and its working method. Background Technology

[0002] Currently, the government is increasing its support for agricultural modernization and integration. Intensive land use, cooperation, and the formation of large-scale industrial groups are the current direction of agricultural development, with large-scale, automated agricultural machinery and company cooperation forming concrete models. Mechanizing cotton harvesting technology to improve harvesting efficiency, free up labor, and reduce production costs is an inevitable trend for future development. Meanwhile, since the cotton harvesting season is only three months or even shorter, ensuring the stability and reliability of cotton harvesters within this timeframe is crucial for farmers. Currently, there is an urgent market demand for domestically produced high-performance, high-reliability cotton harvesters. Therefore, inventing a hydraulic shifting system with a limp-shift function suitable for cotton harvesters and other harvesting and storage machinery is of great significance. Summary of the Invention

[0003] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a hydraulic shift control system with limp function and its working method. The system has multiple operating modes. When the system malfunctions, the limp function can be used to realize the limp operation of the system, so as to avoid serious safety accidents such as collisions or rollovers caused by emergency stopping of the malfunctioning vehicle.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A hydraulic shift control system with limp function includes an oil supply line, which is connected to a cooling and lubrication module, a shift module, a steering module, a parking module, and a manual limp valve. The manual limp valve is connected to the shift module and the parking module respectively. The shift module includes a clutch module and a brake module.

[0006] The parking module includes a parking pressure control valve and a parking brake. An f interface is provided between the parking pressure control valve and the parking brake. The parking pressure control valve is a manual solenoid check valve.

[0007] The manual limp valve is a two-position five-way manual directional valve, including five ports: a, b, c, d, and e. Port a connects to the clutch module, port b connects to the brake module, ports c and d connect to the return port of the oil supply circuit, and port e connects to the outlet port of the oil supply circuit. A directional valve is installed between ports a and b, and the directional valve is connected to port f.

[0008] When the hydraulic shift control system is running normally, interface a is connected to interface d, interface b is connected to interface c, and interface e is closed; in limp mode, interface a is connected to interface d, interface b is connected to interface e, and interface e is open.

[0009] The oil supply circuit includes an oil supply tank, which is connected to a pump oil pressure limiting module. The pump oil pressure limiting module is connected to an oil filter module, which is connected to an accumulator, a sensor module, a cooling and lubrication module, a clutch module, a brake module, a steering module, and a parking pressure control valve.

[0010] The clutch module includes a clutch solenoid control valve and a clutch. The oil supply line is connected to the clutch solenoid control valve, and the clutch solenoid control valve is connected to the clutch and the manual limp valve via interface A.

[0011] The clutch solenoid control valve includes a clutch solenoid valve core and a clutch solenoid control valve slide valve. The clutch solenoid valve core is connected to the a port of the manual limp valve, and the clutch solenoid control valve slide valve is connected to the clutch and the oil supply tank.

[0012] The brake module includes a brake solenoid control valve and a brake. The oil supply line is connected to the brake solenoid control valve, and the brake solenoid control valve is connected to the b interface of the brake and the manual limp valve.

[0013] The brake solenoid control valve includes a brake solenoid valve core and a brake solenoid control valve slide valve. The brake solenoid valve core is connected to the b port of the manual limp valve, and the brake solenoid control valve slide valve is connected to the brake and the oil supply tank.

[0014] The oil filter module is connected to the parking pressure control valve via the parking switch valve.

[0015] The steering module includes a differential solenoid control valve and a differential, and the oil filter module is connected to the differential via the differential solenoid control valve.

[0016] The differential solenoid control valve includes a differential solenoid valve core and a differential solenoid control valve slide valve. The differential solenoid valve core is connected to the oil supply tank, and the differential solenoid control valve slide valve is connected to both the oil supply tank and the differential.

[0017] A method for operating a hydraulic shift control system with limp-off function includes the following steps:

[0018] During normal operation, the hydraulic shift control system operates in the following modes:

[0019] When the parking module and clutch module are powered on, and the steering module and brake module are de-powered, it is in the high-gear highway transport mode.

[0020] When the parking module and brake module are powered on, and the steering module and clutch module are de-powered, it is in the straight-line operation mode in low gear.

[0021] When the parking module, steering module, and brake module are powered on, and the clutch module is de-powered, it is in low gear steering operation mode.

[0022] When the steering module, parking module, clutch module, and brake module are all de-energized, it is in parking brake mode.

[0023] When the control module or power system fails, the steering module, parking module, clutch module, and brake module are all de-energized. The manual limp valve and parking pressure control valve are manually adjusted. All five ports of the manual limp valve (a, b, c, d, and e) are opened, and ports e and b are connected. The return port of the parking pressure control valve is closed, and the oil supply circuit is connected to the brake module and parking brake to achieve limp operation.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] This invention includes an oil supply circuit connected to a cooling and lubrication module, a shifting module, a steering module, a parking module, and a manual limp-action valve. The manual limp-action valve is connected to both the shifting module and the parking module. The shifting module includes a clutch module and a brake module. The shifting module, steering module, and parking module can switch between high and low gears, enabling switching between highway transport mode, straight-line operation mode, and steering operation mode. The manual limp-action valve, in conjunction with the shifting module and the parking module, provides a limp-action function to prevent serious safety accidents such as collisions or rollovers caused by emergency stops of disabled vehicles. The parking module includes a parking pressure control valve and a parking brake. An f-interface is provided between the parking pressure control valve and the parking brake. The parking pressure control valve is a manual solenoid check valve, used to manually activate the parking pressure control valve in case of system failure, thereby connecting the manual limp-action valve and the parking brake, enabling the manual limp-action valve to control the parking brake. The manual limp-action valve is a two-position five-way manual directional valve, including five ports: A, B, C, D, and E. Port A connects to the clutch module, port B connects to the brake module, ports C and D connect to the return port of the oil supply circuit, and port E connects to the outlet port of the oil supply circuit. A directional valve is installed between ports A and B, connecting to port F. The directional valve prevents oil from the shift module outlet from entering the parking brake, thus avoiding interference with normal system operation. During normal operation of the hydraulic shift control system, port A connects to port D, port B connects to port C, and port E is closed. In limp-action mode, port A connects to port D, port B connects to port E, and port E is open. In this mode, the oil supply circuit is connected to both the brake module and the parking brake via the manual limp-action valve, enabling the system's limp-action function.

[0026] Furthermore, the oil supply circuit includes an oil supply tank, which is connected to a pump oil pressure limiting module. The pump oil pressure limiting module is connected to an oil filter module, which in turn is connected to an accumulator, a sensor module, a cooling and lubrication module, a clutch module, a brake module, a steering module, and a parking pressure control valve. The pump oil pressure limiting module provides a constant pressure oil to the hydraulic system, which is beneficial for stable system operation. The oil filter module is used to filter impurities in the oil, keeping it clean. The oil filter module is equipped with a differential pressure switch, which monitors the pressure difference between the oil filter inlet and outlet to determine if the oil filter is clogged, facilitating timely cleaning and replacement of the filter element. The accumulator absorbs pressure shocks and fluctuations, stabilizing the system pressure and also serves as an auxiliary hydraulic power source, further ensuring system stability.

[0027] The method of this invention, through the combined operation of four modules—steering module, parking module, clutch module, and brake module—can achieve high and low gear switching, and switch between highway transportation mode, straight-line operation mode, and steering operation mode. When the control module or power system fails, the manual limp-action valve, in conjunction with the shifting module and parking module, can achieve limp-action function. Specifically, when the steering module, parking module, clutch module, and brake module are all de-energized, the manual limp-action valve and parking pressure control valve are manually adjusted. All five ports of the manual limp-action valve—a, b, c, d, and e—are opened, with port e and b connected. The return port of the parking pressure control valve is closed, and the oil supply circuit is connected to the brake module and parking brake, achieving limp-action operation and avoiding serious safety accidents such as collisions or rollovers caused by emergency stops of disabled vehicles. Attached Figure Description

[0028] Figure 1 This is a hydraulic schematic diagram of the present invention;

[0029] Figure 2 This is a schematic diagram of the high-speed gear hydraulic principle of the present invention;

[0030] Figure 3 This is a schematic diagram of the low-speed straight-line hydraulic principle of the present invention;

[0031] Figure 4 This is a schematic diagram of the low-speed gear steering hydraulic principle of the present invention;

[0032] Figure 5 This is a hydraulic schematic diagram of the limp gear of the present invention.

[0033] The components include: 1. Oil supply tank; 2. Pump oil pressure limiting module; 3. Oil filter module; 4. Accumulator; 5. Sensor module; 6. Cooling and lubrication module; 7. Clutch solenoid control valve; 7-1. Clutch solenoid valve core; 7-2. Clutch solenoid control valve slide valve; 8. Brake solenoid control valve; 8-1. Brake solenoid valve core; 8-2. Brake solenoid control valve slide valve; 9. Differential solenoid control valve; 9-1. Differential solenoid valve core; 9-2. Differential solenoid control valve. 10. Spool valve; 11. Parking switch valve; 12. Parking pressure control valve; 13. Manual limp valve; 14. Directional valve; 15. Cooling and lubrication unit; 16. Clutch; 17. Brake; 18. Differential; 19. Parking brake; 10. Cooling and lubricating oil pressure test point; 11. Clutch pressure test point; 12. Brake pressure test point; 13. Differential pressure test point; 14. Parking brake pressure test point; 15. Parking switch valve outlet pressure test point. Detailed Implementation

[0034] The invention will now be further described with reference to the accompanying drawings.

[0035] like Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, a hydraulic shift control system with limp function includes an oil supply line, which is connected to a cooling and lubrication module 6, a shift module, a steering module, a parking module, and a manual limp valve 12. The shift module includes a clutch module and a brake module.

[0036] The parking module includes a parking pressure control valve 11 and a parking brake 17. An f interface is provided between the parking pressure control valve 11 and the parking brake 17. The parking pressure control valve 11 is a manual solenoid check valve.

[0037] The manual limp valve 12 is a two-position five-way manual directional valve, including five ports: a, b, c, d and e. Port a is connected to the clutch module, port b is connected to the brake module, ports c and d are connected to the return port of the oil supply circuit, and port e is connected to the outlet port of the oil supply circuit. A directional valve 12-1 is installed between ports a and b, and the directional valve 12-1 is connected to port f.

[0038] When the hydraulic shift control system is running normally, interface a is connected to interface d, interface b is connected to interface c, and interface e is closed; in limp mode, interface a is connected to interface d, interface b is connected to interface e, and interface e is open.

[0039] Preferably, the present invention includes an oil supply circuit connected to a cooling and lubrication module 6, a gear shifting module, a steering module, a parking module, and a manual limp-action valve 12. The manual limp-action valve 12 is connected to both the gear shifting module and the parking module. The gear shifting module includes a clutch module and a brake module. The gear shifting module, steering module, and parking module can switch between high and low gears, enabling switching between road transport mode, straight-line operation mode, and steering operation mode. Specifically: when the parking module and clutch module are energized, and the steering module and brake module are de-energized, it is in the high-gear road transport mode. When the parking module and brake module are energized, and the steering module and clutch module are de-energized, it is in the low-gear straight-line operation mode. When the parking module, steering module, and brake module are energized, and the clutch module is de-energized, it is in the low-gear steering operation mode. When the steering module, parking module, clutch module, and brake module are all de-energized, it is in the parking brake mode. The manual limp-walk valve 12, in conjunction with the shift module and parking module, enables limp-walk functionality, preventing serious safety accidents such as collisions or rollovers caused by emergency stops of disabled vehicles. The parking module includes a parking pressure control valve 11 and a parking brake 17. An f-port is provided between the parking pressure control valve 11 and the parking brake 17. The parking pressure control valve 11 is a manual solenoid check valve, used to manually activate the parking pressure control valve 11 in case of system failure, thereby connecting the manual limp-walk valve 12 and the parking brake 17, enabling the manual limp-walk valve 12 to control the parking brake 17. The manual limp-walk valve 12 is a two-position five-way manual directional valve, including five ports: a, b, c, d, and e. Port a connects to the clutch module, port b connects to the brake module, ports c and d connect to the return port of the oil supply circuit, and port e connects to the outlet port of the oil supply circuit. A directional valve 12-1 is provided between ports a and b, and the directional valve 12-1 connects to port f. Directional valve 12-1 is used to prevent oil from the shift module outlet from entering the parking brake 17, thus interfering with the normal operation of the system. During normal operation, interface a is connected to interface d, interface b is connected to interface c, and interface e is closed. At this time, manual limp-action valve 12 connects the shift module to the return port of the oil supply circuit. In limp-action mode, interface a is connected to interface d, and the clutch module is connected to the oil supply circuit inlet through interfaces a and d of manual limp-action valve 12. Interface e is open, and interface b is connected to interface e. Directional valve 12-1 opens due to the oil pressure at interface b of manual limp-action valve 12, activating the brake module. Simultaneously, interface b of manual limp-action valve 12 connects to interface f, unlocking the parking brake 17, thereby achieving the limp-action function of the system, and the vehicle maintains low-gear driving.

[0040] Preferably, the actuation device of the manual limp valve 12 and the actuation device of the parking pressure control valve 11 are integrated into one structure, that is, after a power system failure, if the lever is moved, both the manual limp valve 12 and the parking pressure control valve 11 will switch to the working position.

[0041] Preferred, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the cooling and lubrication module 6 includes a pressure regulating valve, a check valve, and an oil cooler. The cooling and lubrication module 6 is connected to the cooling and lubrication unit 13, which has a cooling and lubrication oil pressure testing point 18-1. The cooling and lubrication module 6 is used to supply cooling and lubrication oil to the gearbox. The check valve is connected in parallel with the oil cooler to ensure that the cooling and lubrication oil path is unobstructed.

[0042] Preferred, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the oil supply circuit includes an oil supply tank 1, which is connected to a pump oil pressure limiting module 2. The pump oil pressure limiting module 2 is connected to an oil filter module 3, which is connected to an accumulator 4, a sensor module 5, a cooling and lubrication module 6, a clutch module, a brake module, a steering module, and a parking pressure control valve 11. The pump oil pressure limiting module 2 provides a constant pressure oil to the hydraulic system, which is beneficial for the stable operation of the system. The oil filter module 3 is used to filter impurities in the oil, keeping the oil clean. The oil filter module 3 is equipped with a differential pressure switch, which can monitor the pressure difference between the oil filter inlet and outlet to determine whether the oil filter is clogged, facilitating timely cleaning and replacement of the filter element. The accumulator 4 absorbs pressure shocks and fluctuations, stabilizing the system pressure, and can also serve as an auxiliary hydraulic source, further ensuring system stability. The sensor module 5 includes a temperature sensor and a pressure sensor, used to monitor the system oil temperature and pressure in real time.

[0043] Preferred, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the clutch module includes a clutch solenoid control valve 7 and a clutch 14. An oil supply line connects to the clutch solenoid control valve 7, which in turn connects to the clutch 14 and the manual limp-out valve 12 via port a. The clutch 14 is the high-speed gear actuator.

[0044] Preferred, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5As shown, the clutch solenoid control valve 7 includes a clutch solenoid valve core 7-1 and a clutch solenoid control valve slide valve 7-2. The clutch solenoid valve core 7-1 is connected to the a port of the manual limp valve 12 and the oil outlet of the oil supply circuit. The clutch solenoid control valve slide valve 7-2 is connected to the clutch 14 and the oil supply circuit. The clutch solenoid control valve slide valve 7-2 switches its working position to realize the connection and disconnection with the clutch 14 and the oil supply circuit.

[0045] Furthermore, a clutch pressure testing point 18-2 is provided between the clutch solenoid control valve slide valve 7-2 and the clutch 14.

[0046] Preferred, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the brake module includes a brake solenoid control valve 8 and a brake 15. An oil supply line is connected to the brake solenoid control valve 8, which is connected to the b-port of the brake 15 and the manual limp-out valve 12. The brake 15 is a low-speed gear actuator.

[0047] like Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the brake solenoid control valve 8 includes a brake solenoid valve core 8-1 and a brake solenoid control valve slide valve 8-2. The brake solenoid valve core 8-1 is connected to the b port of the manual limp valve 12 and the oil outlet of the oil supply line. The brake solenoid control valve slide valve 8-2 is connected to the brake 15 and the oil supply line. The brake solenoid control valve slide valve 8-2 switches its working position to realize the connection and disconnection with the brake 15 and the oil supply line.

[0048] Furthermore, a brake pressure testing point 18-3 is provided between the brake solenoid control valve slide valve 8-2 and the brake 15.

[0049] like Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the oil filter module 3 is connected to the parking pressure control valve 11 via the parking switch valve 10. That is, during normal system operation, the parking brake 17 is jointly controlled by the parking switch valve 10 and the parking pressure control valve 11. The oil outlet of the parking switch valve 10 is connected to the oil inlet of the parking pressure control valve 11. The oil outlet of the parking pressure control valve 11 is connected to the parking brake 17.

[0050] Furthermore, a parking brake pressure test point 18-5 is provided between the f interface and the parking brake 17, and a parking switch valve outlet pressure test point 18-6 is provided between the parking switch valve 10 and the parking pressure control valve 11.

[0051] like Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the steering module includes a differential solenoid control valve 9 and a differential 16, and the oil filter module 3 is connected to the differential 16 through the differential solenoid control valve 9.

[0052] like Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the differential solenoid control valve 9 includes a differential solenoid valve core 9-1 and a differential solenoid control valve slide valve 9-2. The differential solenoid valve core 9-1 is connected to the oil supply circuit, and the differential solenoid control valve slide valve 9-2 is connected to both the oil supply circuit and the differential 16. The differential solenoid control valve slide valve 9-2 switches its working position to achieve the connection and disconnection between the differential 16 and the oil supply circuit.

[0053] Furthermore, a differential pressure test point 18-4 is provided between the differential solenoid control valve slide valve 9-2 and the differential 16.

[0054] Preferably, the clutch solenoid control valve 7, brake solenoid control valve 8, and differential solenoid control valve 9 have the same structure, all being three-position, three-way solenoid directional valves. The high-speed clutch solenoid control valve 7 and the low-speed brake solenoid control valve 8 are both normally closed solenoid valves. The parking switch valve 10 is a normally closed two-position, three-way solenoid valve. When the normally closed solenoid valve is de-energized, the hydraulic oil circuit from the inlet to the outlet is closed.

[0055] Preferably, the clutch 14 includes: a clutch return spring, a clutch piston, a clutch friction plate, a clutch mating plate, a clutch inner hub, a clutch outer hub, and a planetary carrier. A clutch cavity is provided between the clutch outer hub and the clutch inner hub. The clutch piston is located in the clutch cavity, and the clutch return spring is located between the clutch inner hub and the piston. The outer diameter ends of the clutch friction plate and the clutch mating plate are connected to the clutch outer hub, and their inner diameter ends are connected to the clutch inner hub. The clutch friction plate and the clutch mating plate are located between the clutch piston and the planetary carrier.

[0056] The brake 15 includes: a brake return spring, a brake piston, brake friction pads, brake mating pads, a brake housing, and a back plate. A brake cavity is provided between the brake housing and the brake outer hub. The brake piston is located inside the brake cavity, and the brake return spring is located between the brake outer hub and the brake piston; the brake friction pads and brake mating pads are located between the brake piston and the back plate.

[0057] Operating principle of high-speed actuator: In high-speed gear, the clutch solenoid control valve 7 is energized and the brake solenoid control valve 8 is de-energized. Then, the clutch chamber is filled with oil and pressurized. The clutch piston overcomes the mechanical force of the clutch return spring and presses the clutch friction plate, so that the power is transmitted from the inner hub of the clutch to the outer hub of the clutch through the clutch friction plate, thereby achieving high speed.

[0058] Operating principle of low-speed actuator: In low speed, the clutch solenoid control valve 7 is de-energized and the brake solenoid control valve 8 is energized. Then the brake chamber is filled with oil and pressurized, the clutch chamber is depressurized, and the brake piston overcomes the mechanical force of the brake return spring to press the brake friction plate, so that the braking force is transmitted from the brake housing to the brake outer hub, thereby achieving low speed.

[0059] The differential 16 includes: a differential housing, a differential piston, a differential return spring, differential friction plates, differential mating plates, a pressure plate, and a half-shaft gear. A differential cavity is provided between the differential housing and the pressure plate. The differential piston is located within the differential cavity, and the differential return spring is located between the half-shaft gear and the pressure plate. The outer diameter ends of the differential friction plates and differential mating plates are connected to the differential housing, and their inner diameter ends are connected to the half-shaft gear. The differential friction plates and differential mating plates are located between the differential piston and the differential housing.

[0060] When the agricultural machinery needs to turn during low-speed operation, the differential solenoid control valve 9 is energized to engage the differential 16, thus achieving the steering function. When the agricultural machinery needs to deactivate the steering function during high-speed transportation, the differential solenoid control valve 9 is de-energized to unlock the differential 16. The differential actuator operates as follows: After the differential solenoid control valve 9 is energized, the differential chamber is filled with oil and pressurized, pushing the differential piston to overcome the differential return spring and press against the differential friction plates. This allows power to be transmitted from the differential housing through the differential friction plates to the half-shaft gears, thereby achieving the steering function.

[0061] Preferably, the parking brake 17 includes: a parking return spring, a parking piston, a parking friction pad, a parking mating pad, a parking brake outer hub, a parking housing, and a parking back plate.

[0062] A parking chamber is provided between the parking brake housing and the parking brake hub; the parking piston is located within the parking chamber; a parking return spring is located between the parking brake housing and the parking piston; the parking backplate is connected to the parking brake hub by bolts. The outer diameter ends of the parking friction plate and the parking mating plate are connected to the parking brake hub, and the inner diameter ends of the parking mating plate are connected to a rotating shaft. The parking friction plate and the parking mating plate are located between the parking piston and the parking backplate. The axial movement of the parking friction plate and the parking mating plate can be restricted by the parking piston.

[0063] The working principle of the parking brake is as follows: When parking is required, the control system de-energizes the parking switch valve 10 and the parking pressure control valve 11, placing them in the left position. The pressurized oil in the parking chamber drains back to the oil supply tank 1. The parking piston returns to its original position under the force of the parking return spring. The parking friction plate and the parking mating plate are driven to move and press against each other by the parking piston. This locks the rotating shaft and the outer hub of the parking brake, achieving parking braking. When the parking brake needs to be released, the control system energizes the parking switch valve 10 and the parking pressure control valve 11, placing them in the right position. The hydraulic source builds pressure in the parking brake branch, and pressurized oil fills the parking chamber. The pressurized oil overcomes the force of the parking return spring, pushing the parking piston and releasing the braking force transmitted from the outer hub of the brake to the rotating shaft through the parking friction plate.

[0064] Furthermore, when the parking pressure control valve 11 is in the right position, it functions as a one-way valve to prevent the main oil pressure of the system from dropping during gear shifting, which could cause oil backflow in the parking brake chamber and create a driving hazard.

[0065] Preferably, all hydraulic valve assemblies of the present invention can be arranged on a single valve block, thereby facilitating installation on the transmission.

[0066] A method for operating a hydraulic shift control system with limp-off function includes the following steps:

[0067] The corresponding working modes and shifting process of the hydraulic shift control system are as follows:

[0068] like Figure 2 As shown, when the parking module and clutch module are powered on, and the steering module and brake module are de-powered, it is in high gear road transport mode, as detailed below:

[0069] When the clutch solenoid control valve 7 is energized, the brake solenoid control valve 8 is de-energized. After the clutch solenoid control valve 7 is energized, the clutch solenoid valve core 7-1 is in the left position, and the oil circuit is cut off. This forces the oil to apply pressure to the left end of the clutch solenoid control valve slide valve 7-2. The oil pressure overcomes the spring force at the right end of the clutch solenoid control valve slide valve 7-2 and the feedback fluid pressure at the outlet end of the slide valve, causing the clutch solenoid control valve slide valve 7-2 to be in the left position. The oil inlet and outlet of the clutch solenoid control valve slide valve 7-2 are connected, thereby realizing the oil supply to the clutch chamber. The clutch 14 engages to realize high-speed gear operation. After the brake solenoid control valve 8 is de-energized, the brake solenoid valve core 8-1 is in the right position, and the oil inlet and outlet of the brake solenoid valve core 8-1 are connected. The oil outlet of the brake solenoid valve core 8-1 is connected to the oil supply tank 1, so the pressure oil flows back to the oil supply tank 1. Therefore, no hydraulic pressure is applied to the left end of the brake solenoid control valve slide valve 8-2. The brake solenoid control valve slide valve 8-2 is in the right position under the action of the spring force at the right end. At this time, the oil outlet of the brake solenoid control valve slide valve 8-2 is connected to the oil return port of the oil supply circuit, and the pressure oil in the brake cavity flows back to the oil supply tank 1. The brake 15 does not work.

[0070] like Figure 3 As shown, when the parking module and brake module are powered on, and the steering module and clutch module are de-powered, it operates in a low-gear straight-line mode, as detailed below:

[0071] When the clutch solenoid valve 7 is de-energized, the brake solenoid valve 8 is energized. After the brake solenoid valve 8 is energized, the brake solenoid valve core 8-1 is in the left position, and the oil circuit is cut off. This forces the oil to apply pressure to the left end of the brake solenoid valve slide valve 8-2. The oil pressure overcomes the spring force at the right end of the brake solenoid valve slide valve 8-2 and the feedback fluid pressure at the outlet end of the brake solenoid valve slide valve 8-2, causing the brake solenoid valve slide valve 8-2 to be in the left position. The oil inlet and outlet of the brake solenoid valve slide valve 8-2 are connected, thereby realizing the oil supply to the brake chamber. The brake 15 is engaged to realize the low-speed gear operation. After the clutch solenoid control valve 7 is de-energized, the clutch solenoid valve core 7-1 is in the right position, and the oil inlet and outlet of the clutch solenoid valve core 7-1 are connected. The oil outlet of the clutch solenoid valve core 7-1 is connected to the oil supply tank 1, so the pressure oil flows back to the oil supply tank 1. Therefore, no hydraulic pressure is applied to the left end of the clutch solenoid control valve slide valve 7-2. The clutch solenoid control valve slide valve 7-2 is in the right position under the action of the spring force at the right end. At this time, the oil outlet of the clutch solenoid control valve slide valve 7-2 is connected to the oil return port of the oil supply tank 1, and the pressure oil in the clutch chamber flows back to the oil supply tank 1. The clutch 14 does not work.

[0072] like Figure 4As shown, when the parking module, steering module, and brake module are powered on, and the clutch module is de-powered, it operates in a low-gear steering mode, as detailed below:

[0073] When agricultural machinery is operating in low gear or stuck in mud, the differential needs to be engaged. The driver presses the differential lock button to energize the differential solenoid valve 9. The differential solenoid valve core 9-1 is in the left position, cutting off the oil circuit of the differential solenoid valve core 9-1. This forces the oil to apply pressure to the left end of the differential solenoid valve slide valve 9-2. The oil pressure overcomes the spring force at the right end of the differential solenoid valve slide valve 9-2 and the feedback fluid pressure at the outlet end of the differential solenoid valve slide valve 9-2, keeping the differential solenoid valve slide valve 9-2 in the left position. The oil inlet and outlet of the differential solenoid valve slide valve 9-2 are connected, thus achieving oil supply to the differential chamber, and the differential 16 engages. When the agricultural machinery is in a straight-line working condition for road transport or operation, and the differential 16 does not need to engage, the driver can press the differential lock button to disconnect the power supply to the differential solenoid control valve 9. The differential solenoid valve core 9-1 will then be in the right position, and the oil inlet and outlet of the differential solenoid valve core 9-1 will be connected. The oil outlet of the differential solenoid valve core 9-1 will be connected to the oil supply tank 1, thus the pressurized oil will flow back to the oil supply tank 1. Therefore, no hydraulic pressure will act on the left end of the differential solenoid control valve slide valve 9-2. The differential solenoid control valve slide valve 9-2 will then be in the right position under the action of the spring force at the right end. At this time, the oil outlet and return port will be connected, and the pressurized oil in the differential chamber will flow back to the oil supply tank 1, thus unlocking the differential 16.

[0074] When the steering module, parking module, clutch module, and brake module are all de-energized, it is in parking brake mode.

[0075] The following table shows the shifting logic diagram during normal operation:

[0076]

[0077] like Figure 5 As shown, when the control module or power system malfunctions, the steering module, parking module, clutch module, and brake module are all de-energized. The manual limp-action valve 12 and parking pressure control valve 11 are manually adjusted. All five ports of the manual limp-action valve 12 (a, b, c, d, and e) are opened, with port e and b connected. The return port of the parking pressure control valve 11 is closed, and the oil supply circuit connects the brake module and parking brake 17, achieving limp-action operation, as detailed below:

[0078] The manual limp-action valve 12 has its port a connected to the return port of the clutch solenoid valve core 7-1, port b connected to the return port of the brake solenoid valve core 8-1, port c connected to the oil supply tank 1, port d connected to the oil supply tank 1, port e connected to the main oil circuit, and port f located between the outlet of the parking pressure control valve 11 and the parking brake 17. Through the action of the directional valve 12-1, the outlet pressure oil of the parking pressure control valve 11 cannot flow into the manual limp-action valve 12. Simultaneously, the drain oil from the clutch solenoid valve core 7-1 and the brake solenoid valve core 8-1 cannot flow into the parking brake 17 because the directional valve 12-1 cannot be opened. When the system is working normally, the manual limp-action valve 12 is in the right position, port e is closed, and therefore the pressure oil from the oil supply circuit cannot enter the manual limp-action valve 12. When the high-speed and low-speed gears are operating normally, the oil return port of the solenoid valve core 7-1 of the clutch solenoid control valve is connected to interface a, and interface a is connected to interface d. Therefore, the oil return port of the clutch solenoid valve core 7-1 is normally connected to the oil supply tank 1. The oil return port of the brake solenoid valve core 8-1 is connected to interface b, and interface b is connected to interface c. Therefore, the oil return port of the brake solenoid valve core 8-1 is normally connected to the oil supply tank 1.

[0079] When the transmission control module or electrical system malfunctions, all solenoid valves in the hydraulic control system are de-energized, and the clutch solenoid valve core 7-1 and the brake solenoid valve core 8-1 are in the right position. At this time, manually controlling the manual limp-out valve 12 to operate in the left position connects the return port of the clutch solenoid valve core 7-1 to port a, and port a is connected to port d. Therefore, the return port of the clutch solenoid valve core 7-1 is normally connected to the oil supply tank 1. At this time, the inlet and outlet ports of the clutch solenoid control valve spool 7-2 are not connected, therefore the clutch does not operate. The return port of the brake solenoid valve core 8-1 is connected to port b, which is connected to port e. Port e is connected to the oil supply circuit. Therefore, the left end of the brake solenoid control valve slide valve 8-2 can be subjected to hydraulic pressure. This hydraulic pressure overcomes the spring force at the right end of the brake solenoid control valve slide valve 8-2 and the feedback hydraulic pressure, so that the brake solenoid control valve slide valve 8-2 is in the left position. At this time, the oil inlet and outlet of the brake solenoid control valve slide valve 8-2 are connected, the brake chamber is filled with oil and pressure is built up, the brake 15 is working, and low-speed driving is realized.

[0080] When the transmission control module or the electrical system malfunctions, all solenoid valves in the hydraulic control system are de-energized. The parking switch valve 10 and the parking pressure control valve 11 are both in the left position. The pressurized oil from the oil supply circuit flows from the eb port connected to the manual limp valve 12 to the directional valve 12-1. The directional valve 12-1 cuts off the flow of pressurized oil between the b port and the clutch solenoid valve core 7-1. The directional valve 12-1 is connected to the f port, so the pressurized oil flows to the f port. The parking pressure control valve 11 is switched to the right position by the operation of the manual device, so the pressurized oil can only flow in one direction to fill and pressurize the parking brake chamber, thereby unlocking the parking brake and allowing the vehicle to drive safely in a low gear.

[0081] Preferably, the method of the present invention, through the combined operation of four modules—steering module, parking module, clutch module, and brake module—can achieve high and low gear switching, and switch between highway transportation mode, straight-line operation mode, and steering operation mode. When the control module or power system fails, the manual limp valve 12, in conjunction with the shifting module and parking module, can achieve limp operation. Specifically, when the steering module, parking module, clutch module, and brake module are all de-energized, the manual limp valve 12 and parking pressure control valve 11 are manually adjusted. All five ports of the manual limp valve 12—a, b, c, d, and e—are opened, with port e and b connected. The return port of the parking pressure control valve 11 is closed, and the oil supply circuit is connected to the brake module and parking brake 17, achieving limp operation. This avoids serious safety accidents such as collisions or rollovers caused by emergency stopping of a disabled vehicle, allowing the vehicle to be driven in low gear to a repair location for vehicle maintenance.

[0082] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A hydraulic shift control system with limp-shift function, characterized in that, It includes an oil supply circuit, which includes an oil supply tank (1). The oil supply circuit is connected to a cooling and lubrication module (6), a shift module, a steering module, a parking module, and a manual limp valve (12). The manual limp valve (12) is connected to the shift module and the parking module respectively. The shift module includes a clutch module and a brake module. The parking module includes a parking pressure control valve (11) and a parking brake (17). An f interface is provided between the parking pressure control valve (11) and the parking brake (17). The parking pressure control valve (11) is a manual solenoid check valve. The manual limp valve (12) is a two-position five-way manual directional valve, including five ports: a, b, c, d and e. Port a is connected to the clutch module, port b is connected to the brake module, ports c and d are connected to the return port of the oil supply circuit, port e is connected to the outlet port of the oil supply circuit, ports a and b are connected to the inlet port of the directional valve (12-1), and the outlet port of the directional valve (12-1) is connected to port f. When the hydraulic shift control system is running normally, interface a is connected to interface d, interface b is connected to interface c, and interface e is closed; in limp mode, interface a is connected to interface d, interface b is connected to interface e, and interface e is open. The clutch module includes a clutch solenoid control valve (7) and a clutch (14). The oil supply line is connected to the clutch solenoid control valve (7). The clutch solenoid control valve (7) is connected to the clutch (14) and the manual limp valve (12) at interface a. The clutch solenoid control valve (7) includes a clutch solenoid valve core (7-1) and a clutch solenoid control valve slide valve (7-2). The clutch solenoid valve core (7-1) is connected to the a port of the manual limp valve (12) and the oil outlet of the oil supply circuit. The clutch solenoid control valve slide valve (7-2) is connected to the clutch (14) and the oil supply circuit. The brake module includes a brake solenoid control valve (8) and a brake (15). The oil supply line is connected to the brake solenoid control valve (8). The brake solenoid control valve (8) is connected to the b interface of the brake (15) and the manual limp valve (12). The brake solenoid control valve (8) includes a brake solenoid valve core (8-1) and a brake solenoid control valve slide valve (8-2). The brake solenoid valve core (8-1) is connected to the b port of the manual limp valve (12) and the oil outlet of the oil supply circuit. The brake solenoid control valve slide valve (8-2) is connected to the brake (15) and the oil supply circuit. When the transmission control module or the power system malfunctions, the return port of the clutch solenoid valve core (7-1) is connected to the oil supply tank (1) normally through the manual limp valve (12). The inlet and outlet ports of the clutch solenoid control valve slide valve (7-2) are in a non-conductive state. The return port of the brake solenoid valve core (8-1) is connected to the oil supply circuit through the manual limp valve (12). Therefore, the left end of the brake solenoid control valve slide valve (8-2) is subjected to hydraulic pressure. This hydraulic pressure makes the inlet and outlet ports of the brake solenoid control valve slide valve (8-2) connect, thereby realizing low-speed driving.

2. A hydraulic shift control system with limp-shift function as described in claim 1, characterized in that, The oil supply tank (1) is connected to the oil pump pressure limiting module (2), the oil pump pressure limiting module (2) is connected to the oil filter module (3), and the oil filter module (3) is connected to the accumulator (4), the sensor module (5), the cooling and lubrication module (6), the clutch module, the brake module, the steering module and the parking pressure control valve (11) respectively.

3. A hydraulic shift control system with limp-shift function as described in claim 2, characterized in that, The oil filter module (3) is connected to the parking pressure control valve (11) via the parking switch valve (10).

4. A hydraulic shift control system with limp-shift function as described in claim 2, characterized in that, The steering module includes a differential solenoid control valve (9) and a differential (16), and the oil filter module (3) is connected to the differential (16) through the differential solenoid control valve (9).

5. A hydraulic shift control system with limp-shift function as described in claim 4, characterized in that, The differential solenoid control valve (9) includes a differential solenoid valve core (9-1) and a differential solenoid control valve slide valve (9-2). The differential solenoid valve core (9-1) is connected to the oil supply circuit, and the differential solenoid control valve slide valve (9-2) is connected to the oil supply circuit and the differential (16) respectively.

6. A method for operating a hydraulic shift control system with limp-shift function as described in claim 1, characterized in that, Includes the following steps: During normal operation, the hydraulic shift control system operates in the following modes: When the parking module and clutch module are powered on, and the steering module and brake module are de-powered, it is in the high-gear highway transport mode. When the parking module and brake module are powered on, and the steering module and clutch module are de-powered, it is in the straight-line operation mode in low gear. When the parking module, steering module, and brake module are powered on, and the clutch module is de-powered, it is in low gear steering operation mode. When the steering module, parking module, clutch module and brake module are all de-energized, it is in parking brake mode; When the transmission control module or the power system fails, the steering module, parking module, clutch module and brake module are all de-energized. The manual limp valve (12) and the parking pressure control valve (11) are manually adjusted. All five ports of the manual limp valve (12)—a, b, c, d and e—are opened. The e port and b port are connected. The return port of the parking pressure control valve (11) is closed. The oil supply circuit is connected to the brake module and the parking brake (17) to achieve limp operation.

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