Control method of gearbox combining power gear shifting and electric control hydraulic mechanical gear shifting

Abstract

The control method of the gearbox combining power gear shifting and electric control hydraulic mechanical gear shifting comprises the following steps that S1, a clutch proportional valve is controlled to apply a pre-combination pressure value to a target clutch, wherein the target clutch refers to a clutch to be combined with a clutch driven gear; s2, pressurizing the target clutch, controlling the rotating speed of the target clutch to approach to the rotating speed of the engine, or adjusting the rotating speed of the engine to approach to the rotating speed of the target clutch; and the proportional valve is controlled to directly pressurize the target clutch to the working pressure value to be combined with the clutch driven gear. According to the control method of closed-loop joint control, different boosting rates under various working condition loads can be self-adapted, the slip wear loss of the clutch is reduced, the efficiency and the reliability are improved, and smooth and rapid starting and gear shifting are achieved.

Description

Technical Field

[0001] This invention relates to the field of gearbox control, and in particular to a control method for a gearbox that combines power shifting and electro-hydraulic-mechanical shifting. Background Technology

[0002] In the field of automatic transmissions for agricultural machinery and heavy vehicles, power shift technology is the cornerstone of efficient operation. A key challenge is minimizing clutch slippage during engagement while ensuring smooth and rapid gear shifts. Clutch slippage not only directly leads to decreased transmission efficiency and poor fuel economy, but it is also the root cause of overheating, burning, and premature wear in the clutch assembly, severely impacting the reliability and lifespan of the transmission system.

[0003] To achieve smooth shifting, existing technologies generally employ multi-stage clutch pressure control strategies based on fixed parameters. Referring to Chinese patent document CN117989311A, this document provides a power shift tractor transmission control module and implementation method, enabling high and low power gears and power reversal functions. Shifting control is achieved through a gearbox controller, employing multiple control methods for various operating conditions, but all methods control the gear position control valve according to a set curve. This fixed-parameter control mode has a systemic flaw in reducing slippage loss when dealing with complex and variable workloads: if smoothness is pursued by prolonging the slippage process, wear will inevitably increase; if engagement time is shortened to reduce wear, shifting shock will occur. A fixed set of control parameters cannot simultaneously optimize this contradiction under varying operating conditions. Therefore, the shifting process in existing technologies often sacrifices clutch durability and transmission efficiency for basic smoothness. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a control method for a transmission that combines power shifting and electro-hydraulic mechanical shifting. Through a closed-loop dynamic adaptive control method, the slippage loss of the clutch is reduced, achieving both smooth and rapid starting and shifting.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A control method for a gearbox that combines power shift and electro-hydraulic mechanical shift, wherein the gearbox includes: an input shaft assembly, an intermediate shaft assembly, a secondary transmission shaft assembly, an idler gear shaft assembly, and an output shaft assembly;

[0007] The input shaft assembly includes an input shaft A, several clutches mounted on the input shaft A, and a power shift gear that serves as the driven gear of the clutches. Power is transmitted from the input shaft A to the intermediate shaft assembly through the clutches and the power shift gear. The clutches are controlled by a clutch switching valve and a clutch proportional valve. The engine outputs power to the input shaft A. The driving wheel of the clutch is fixedly connected to the input shaft A and rotates synchronously.

[0008] The intermediate shaft assembly includes an intermediate shaft B and several gears mounted on the intermediate shaft B, which are used to transmit power to the idler shaft assembly or the secondary transmission shaft assembly at different speeds. A speed sensor n1 is mounted on the intermediate shaft assembly.

[0009] The idler shaft assembly includes an idler shaft F and an idler wheel mounted on the idler shaft F, used to change the transmission direction of the gears on the secondary transmission shaft assembly;

[0010] The auxiliary transmission shaft assembly includes an auxiliary transmission shaft C and a synchronizer group and transmission gears disposed on the auxiliary transmission shaft C. The synchronizer group includes several synchronizers and gears corresponding to the synchronizers, used to switch different gears and transmit power to the output shaft assembly. The synchronizers are controlled by synchronizer switching valves.

[0011] The output shaft assembly includes an output shaft G, which is used to output torque and speed to the wheels to drive the vehicle;

[0012] It is also equipped with a temperature sensor to monitor the oil temperature inside the transmission. During vehicle operation, if the temperature exceeds the preset limit, a warning will be given. If the temperature exceeds the safe limit, power will be interrupted and the corresponding hydraulic valve of the clutch will be closed to disengage the clutch.

[0013] The control method includes the following steps:

[0014] S1. Control the clutch proportional valve to apply a pre-engagement pressure value to the target clutch, where the target clutch refers to the clutch to be engaged with the clutch driven gear;

[0015] S2. Apply pressure to the target clutch to control the speed of the target clutch to approach the speed of the engine, or adjust the speed of the engine to approach the speed of the target clutch.

[0016] S3. Based on the detection value of the speed sensor n1, the speed value of the driven gear of the target clutch is obtained, and based on the engine speed value, the speed value of the driving wheel of the target clutch is obtained. When the difference between the speed value of the driven gear of the target clutch and the speed value of the driving wheel of the target clutch is less than a predetermined threshold, the proportional valve is controlled to directly pressurize the target clutch to the working pressure value, so that it is fully engaged, thereby realizing the synchronous rotation of the driving wheel of the clutch and the driven gear of the clutch.

[0017] In some embodiments, during start-up or upshift control, step S2 includes: first pressurizing the target clutch at a pressurization rate, and then pressurizing the target clutch at a higher pressurization rate after the detection value of the speed sensor n1 reaches a predetermined value.

[0018] In some embodiments, the predetermined value in step S2 is 10-20 rpm, and the predetermined threshold in step S3 is 20-30 rpm.

[0019] In some embodiments, the start-up control method specifically includes the following steps:

[0020] A1. Open the synchronizer switch valve corresponding to the target gear;

[0021] A2. Open the clutch switch valve of the target clutch;

[0022] A3. Open the clutch proportional valve of the target clutch and apply a pre-engagement pressure value within a predetermined time to drive the clutch driven wheel to move slightly, in order to promote the engagement of the rear synchronizer.

[0023] A4. Control the clutch proportional valve of the target clutch to apply a calibrated effective starting pressure to the target clutch and gradually increase the pressure at the first predetermined pressure rate;

[0024] A5. When the detection value of speed sensor n1 reaches the predetermined value, pressurize the target clutch at a higher second predetermined pressure rate;

[0025] A6. The speed value on the driven gear of the target clutch is obtained based on the detection value of the speed sensor n1, and the speed value of the driving wheel of the target clutch is obtained based on the engine speed value. When the difference between the speed value on the driven gear of the target clutch and the speed value of the driving wheel of the target clutch is less than the first threshold, the proportional valve is controlled to directly pressurize the target clutch to the working pressure value so that it is fully engaged, thereby realizing the synchronous rotation of the driving wheel and the driven gear of the clutch.

[0026] In some embodiments, the clutch power gear upshift control method specifically includes the following steps:

[0027] B1. Control the clutch proportional valve to give the target clutch a pre-engagement pressure value and open the clutch switching valve of the target clutch.

[0028] B2. Control the clutch proportional valve of the current clutch to reduce the pressure to the pre-engagement pressure value within a predetermined time to complete the gear shift. The current clutch refers to the clutch corresponding to the current gear.

[0029] B3. Close the clutch switch valve and clutch proportional valve of the current clutch, and control the clutch proportional valve to apply pressure to the target clutch smoothly at the third predetermined pressure rate.

[0030] B4. When the speed sensor n1 is detected to have reached a predetermined value, the target clutch in the clutch assembly is pressurized at a higher fourth predetermined pressure rate.

[0031] B5. Based on the detection value of speed sensor n1, the speed value on the driven gear of the target clutch is obtained, and based on the engine speed value, the speed value of the driving wheel of the target clutch is obtained. When the difference between the speed value on the driven gear of the target clutch and the speed value of the driving wheel of the target clutch is less than the second threshold, the control proportional valve directly pressurizes the target clutch to the working pressure value, so that it is fully engaged, thereby realizing the synchronous rotation of the driving wheel and the driven gear of the clutch.

[0032] In some embodiments, the clutch power gear downshift control method specifically includes the following steps:

[0033] C1. Open the clutch switch valve of the target clutch, control the clutch proportional valve to give the target clutch a pre-engagement pressure value, and at the same time control the clutch proportional valve to reduce the pressure of the current clutch within a predetermined time, where the current clutch refers to the clutch corresponding to the current gear.

[0034] C2. After the current clutch drops to the pre-engagement pressure value, quickly close the switching valve and proportional valve of the current clutch, and control the proportional valve of the target clutch to pressurize the target clutch at the fifth predetermined pressure rate.

[0035] C3. Based on the detection value of the speed sensor n1, obtain the speed value of the driven gear of the target clutch; based on the engine speed value, obtain the speed value of the driving wheel of the target clutch; and control the engine speed to approach the speed of the driven gear of the target clutch.

[0036] C4. When the difference between the speed value on the driven gear of the target clutch and the speed of the driving wheel of the target clutch is less than the third threshold, the control proportional valve directly pressurizes the target clutch to the working pressure value, so that it is fully engaged, thereby realizing the synchronous rotation of the driving wheel and the driven gear of the clutch.

[0037] C5. Restore engine throttle speed after the target clutch is fully engaged.

[0038] In some embodiments, when shifting gears under operating conditions, the pressure value for switching between the current clutch and the target clutch is 6.5-8 bar, and when shifting gears under road conditions, the shifting pressure value is 1.5-2.5 bar. In these embodiments, the load rate of the engine load data exceeds a preset ratio, and this state is stably maintained for a predetermined time without interruption. That is, as an operating condition, the current clutch refers to the clutch corresponding to the current gear.

[0039] In some embodiments, the shifting and upshifting control method for synchronizer mechanical gears specifically includes the following steps:

[0040] D1. Control the proportional valve of the current clutch to reduce the pressure of the current clutch to a first predetermined pressure value, where the current clutch refers to the clutch corresponding to the current gear.

[0041] D2. Close the synchronizer switch valve corresponding to the current gear, and open the synchronizer switch valve corresponding to the target gear to shift gears;

[0042] D3. After the mechanical gear synchronizer completes the shift, the proportional valve of the current clutch is pressurized to the second predetermined pressure value within a predetermined time, and then pressurized at the sixth predetermined pressure rate. When the speed sensor n1 is detected to have reached the predetermined value, the pressure is increased at a higher seventh predetermined pressure rate.

[0043] D4. Based on the detection value of speed sensor n1, the speed value on the driven gear of the target clutch is obtained. Based on the engine speed value, the speed value of the driving wheel of the target clutch is obtained. When the difference between the speed value on the driven gear of the front clutch and the speed value of the driving wheel of the target clutch is less than the fourth threshold, the proportional valve is controlled to directly pressurize the current clutch to the working pressure value so that it is fully engaged, thereby realizing the synchronous rotation of the driving wheel and the driven gear of the clutch. The current clutch is the target clutch.

[0044] In some embodiments, the shifting and downshifting control method of the synchronizer mechanical gear specifically includes the following steps:

[0045] E1. Control the proportional valve of the current clutch to reduce the pressure of the current clutch to the third predetermined pressure value, where the current clutch refers to the clutch corresponding to the current gear.

[0046] E2. Close the synchronizer switch valve corresponding to the current gear, and open the synchronizer switch valve corresponding to the target gear to shift gears.

[0047] E3. After the mechanical gear synchronizer completes the shift, the proportional valve of the current clutch is pressurized to the fourth predetermined pressure value within a predetermined time. The engine speed value is obtained. Based on the detection value of the speed sensor n1, the speed value on the driven gear of the target clutch is obtained, and the engine speed is controlled to increase to the same speed.

[0048] E4. When the difference between the speed value on the driven gear of the target clutch and the engine speed value is less than the fifth threshold, the control proportional valve directly pressurizes the target clutch to the working pressure value, so that it is fully engaged, thereby realizing the synchronous rotation of the clutch driving wheel and the clutch driven gear.

[0049] E5. Once the target clutch is fully engaged, control the engine speed to return to the throttle speed.

[0050] In some embodiments, the power gears on the input shaft assembly include: a fourth-speed gear, a third-speed gear, a second-speed gear, and a first-speed gear; the clutches include: a fourth-speed clutch, a third-speed clutch, a second-speed clutch, and a first-speed clutch; the engine is connected to the left side of the input shaft A; the fourth-speed gear, the third-speed gear, the second-speed gear, and the first-speed gear are loosely fitted onto the input shaft A; the fourth-speed gear can be connected to the input shaft A and rotate synchronously via the fourth-speed clutch; the third-speed gear can be connected to the input shaft A and rotate synchronously via the third-speed clutch; the second-speed gear can be connected to the input shaft A and rotate synchronously via the second-speed clutch; and the first-speed gear can be connected to the input shaft A and rotate synchronously via the first-speed clutch. By engaging and disengaging the fourth-speed clutch, the third-speed clutch, the second-speed clutch, and the first-speed clutch, control of four gears can be achieved.

[0051] The intermediate shaft component includes several gears mounted on intermediate shaft B, including: a reverse gear, a first gear, a second gear, a third gear, a fourth gear, a fifth gear, and a sixth gear mounted on intermediate shaft B. The first gear meshes with the fourth gear, the third gear meshes with the third gear, the fifth gear meshes with the second gear, and the sixth gear meshes with the first gear.

[0052] The idler shaft assembly specifically includes: an idler shaft F and an idler wheel loosely fitted on the idler shaft F, the idler wheel meshing with the reverse gear for transmission;

[0053] The synchronizer assembly mounted on the secondary transmission shaft C includes: a reverse gear, a mechanical first gear, a mechanical second gear, a first synchronizer, and a second synchronizer. The transmission gears include: an eighth transmission gear and a seventh transmission gear. The reverse gear, mechanical first gear, and mechanical second gear are loosely fitted onto the secondary transmission shaft C. The eighth and seventh transmission gears are fixedly fitted onto the secondary transmission shaft C. Both the first and second synchronizers are mounted on the secondary transmission shaft C. The reverse gear meshes with the idler gear, the mechanical first gear meshes with the second transmission gear, and the mechanical second gear meshes with the fourth transmission gear. The reverse gear can be connected to and rotate synchronously on the secondary transmission shaft C via the first synchronizer. The mechanical first and second gears can be connected to and rotate synchronously on the secondary transmission shaft C via the second synchronizer. The left and right shifting of gears via the second synchronizer allows for gear control; shifting gears via the first synchronizer allows for reverse gear.

[0054] The output components specifically include: output shaft G, high-gear output gear, low-gear output gear, and third synchronizer; both the high-gear and low-gear output gears are loosely fitted on the output shaft G, the high-gear output gear meshes with the eighth transmission gear, and the low-gear output gear meshes with the seventh transmission gear; by shifting gears left and right using the third synchronizer, two gear positions can be controlled.

[0055] The present invention has the following beneficial effects:

[0056] This invention, by applying a pre-engagement pressure value to the target clutch, enables the clutch to engage from a relatively low pressure value, ensuring smooth vehicle operation. When the difference between the speed value on the driven gear of the target clutch and the speed value on the driving wheel of the target clutch is less than a predetermined threshold, the control proportional valve directly pressurizes the target clutch to the working pressure value, making it fully engaged. This achieves synchronous rotation of the driving wheel and driven gear of the clutch. The clutch engagement pressure can be adjusted based on real-time feedback from the speed sensor, minimizing the high-wear and slippage stage of the clutch and accelerating the clutch engagement speed while reducing clutch wear. This closed-loop dynamic adaptive control method ensures smooth and efficient shifting and starting under different operating conditions.

[0057] In step S2, the target clutch is first pressurized at a certain pressurization rate. If the detection value of the speed sensor n1 reaches the predetermined value, the target clutch is pressurized at a higher pressurization rate. The pressurization is adjusted according to the actual vehicle response, ensuring that the shifting is both smooth and efficient under different operating conditions. By increasing the pressure rate, the overall shifting time can be shortened and the overall clutch slippage time can be reduced. Attached Figure Description

[0058] Figure 1 This is a schematic diagram of the transmission principle of the gearbox body;

[0059] Figure 2 This is a schematic diagram of the hydraulic system of the gearbox;

[0060] Figure 3 This is a schematic diagram illustrating the control relationships between the gearbox body, hydraulic system, and control module.

[0061] Explanation of reference numerals in the attached figures:

[0062] A. Input shaft; 2. Power 4th gear; 3. Power 3rd gear; 4. Power 2nd gear; 5. Power 1st gear; B. Intermediate shaft; 6. Reverse gear; 7. First gear; 8. Second gear; 9. Third gear; 10. Fourth gear; 11. Fifth gear; 12. Sixth gear; F. Idler shaft; 14. Idler; C. Secondary transmission shaft; 15. Reverse gear; 16. Mechanical 1st gear; 17. Mechanical 2nd gear; 18. Eighth gear; 19. Seventh gear; 20. High gear output gear; 21. Low gear output gear; D. Front output unit; 22. Fourth synchronizer; E. Rear output unit; 23. Fourth gear clutch; 24. Third gear clutch; 25. Second gear clutch; 26. First gear clutch; 27. First synchronizer; 28. Second synchronizer; 29. ​​Third synchronizer; 30. Front drive / four-wheel drive switching gear; G. Output shaft; 31. Working oil pump; 34. Reverse gear cylinder; 35. First gear cylinder; 36. Second gear cylinder; 37. High / low gear cylinder; 38. Four-wheel drive cylinder; 41. Speed ​​measuring gear; S1. Main transmission gear position valve block; S2. Auxiliary transmission gear position valve block; S3. High / low gear position valve block; S4. Four-wheel drive valve block. Detailed Implementation

[0063] The embodiments of the present invention will be described in detail below. It should be emphasized that the following description is merely exemplary and not intended to limit the scope and application of the present invention.

[0064] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as "connected to" another component, it can be directly connected to or indirectly connected to that other component. Furthermore, a connection can be used for fixing, coupling, or communication.

[0065] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0066] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0067] The control method of the gearbox combining power shift and electro-hydraulic mechanical shift in this embodiment of the invention is referenced. Figure 1 The gearbox includes: an input shaft assembly, an intermediate shaft assembly, a secondary transmission shaft assembly C, an idler shaft assembly F, and an output shaft assembly G;

[0068] The input shaft assembly includes an input shaft A, several clutches mounted on the input shaft A, and a power shift gear that serves as the driven gear of the clutches. Power is transmitted from the input shaft A to the intermediate shaft assembly through the clutches and the power shift gear. The clutches are controlled by a clutch switching valve and a clutch proportional valve.

[0069] The intermediate shaft assembly includes an intermediate shaft B and several gears mounted on the intermediate shaft B, which are used to transmit power to the idler shaft assembly or the secondary transmission shaft assembly at different speeds. A speed sensor n1 is mounted on the intermediate shaft assembly.

[0070] The idler shaft assembly includes an idler shaft F and an idler wheel mounted on the idler shaft F, used to change the transmission direction of the gears on the secondary transmission shaft assembly;

[0071] The auxiliary transmission shaft assembly includes an auxiliary transmission shaft C and a synchronizer group and transmission gears disposed on the auxiliary transmission shaft C. The synchronizer group includes several synchronizers and gears corresponding to the synchronizers, used to switch different gears and transmit power to the output shaft assembly. The synchronizers are controlled by synchronizer switching valves.

[0072] The output shaft assembly is used to output torque and speed to the wheels to drive the vehicle;

[0073] It is also equipped with a temperature sensor to monitor the oil temperature inside the transmission. During vehicle operation, if the temperature exceeds the preset limit, a warning will be given. If the temperature exceeds the safe limit, power will be interrupted and the corresponding hydraulic valve of the clutch will be closed to disengage the clutch.

[0074] The control method includes the following steps:

[0075] S1. Control the clutch proportional valve to apply a pre-engagement pressure value to the target clutch, where the target clutch refers to the clutch to be engaged with the clutch driven gear;

[0076] S2. Apply pressure to the target clutch to control the speed of the target clutch to approach the speed of the engine, or adjust the speed of the engine to approach the speed of the target clutch.

[0077] S3. Based on the detection value of speed sensor n1, the speed value on the driven gear of the target clutch is obtained. Based on the engine speed value, the speed value of the driving wheel of the target clutch is obtained. When the difference between the speed value on the driven gear of the target clutch and the speed value of the driving wheel of the target clutch is less than a predetermined threshold, the proportional valve is controlled to directly pressurize the target clutch to the working pressure value, so that it is fully engaged, thereby realizing the synchronous rotation of the driving wheel and the driven gear of the clutch. The control method of this embodiment enables the gearbox to adapt to different pressure increase rates under various working conditions and loads, reduces clutch slippage, and improves efficiency and reliability.

[0078] refer to Figures 2-3 The transmission control method of the transmission combining power shifting and electro-hydraulic mechanical shifting in this embodiment of the invention utilizes a transmission structure including: a transmission body, a hydraulic system, and a control module. The control module collects speed and pressure signals from the transmission and controls the proportional valve and switching valve in the hydraulic unit to operate. Based on the control signals issued by the control module, the hydraulic unit outputs corresponding pressure to push the hydraulic cylinder through the actions of the proportional valve and switching valve, thereby achieving gear engagement. In this embodiment, a speed measuring gear 41 is fixedly installed on the output shaft G. A first speed sensor n1 for detecting the speed of the reverse gear 6 is installed inside the transmission. In this embodiment, a speed sensor n2 is installed on the output shaft component to detect the speed of the speed measuring gear 41, used for vehicle speed and mechanical gear monitoring. Both the first speed sensor n1 and the speed sensor n2 are connected to the control module. In this embodiment, the controller of the control module can collect the pressure signal from the pressure sensor P and the signals from the speed sensors n1 and n2, and output the control signals, status information, and diagnostic information of the proportional valve and the switching valve. The power shift is controlled by closed-loop adaptive control based on the output speed and acceleration to achieve smooth and quick start and shift. When the gear is engaged, the speed sensor and the calculated speed ratio value are used to monitor in real time to prevent overload slippage and interrupt power to protect the clutch.

[0079] In this embodiment and some other embodiments, step S2 includes: first pressurizing the target clutch at a pressurization rate, and if the detection value of the speed sensor n1 reaches a predetermined value, then pressurizing the target clutch at a higher pressurization rate.

[0080] In this embodiment and some other embodiments, the predetermined value in step S2 is 10-20 rpm, and the predetermined threshold in step S3 is 20-30 rpm.

[0081] In this embodiment and some other embodiments, the start-up control method specifically includes the following steps:

[0082] A1. Open the synchronizer switch valve corresponding to the target gear;

[0083] A2. Open the clutch switch valve of the target clutch;

[0084] A3. Open the clutch proportional valve of the target clutch and apply a pre-engagement pressure value within a predetermined time to drive the clutch driven wheel to move slightly, in order to promote the engagement of the rear synchronizer.

[0085] A4. Control the clutch proportional valve of the target clutch to apply a calibrated effective starting pressure to the target clutch and gradually increase the pressure at the first predetermined pressure rate;

[0086] A5. When the detection value of speed sensor n1 reaches the predetermined value, pressurize the target clutch at a higher second predetermined pressure rate;

[0087] A6. Based on the detection value of speed sensor n1, the speed value of the driven gear of the target clutch is obtained. Based on the engine speed value, the speed value of the driving wheel of the target clutch is obtained. When the difference between the speed value of the driven gear of the target clutch and the speed value of the driving wheel of the target clutch is less than a first threshold (predetermined threshold), the proportional valve is controlled to directly pressurize the target clutch to the working pressure value, so that it is fully engaged, thereby realizing the synchronous rotation of the driving wheel and the driven gear of the clutch. This closed-loop adaptive control method enables the vehicle to achieve smooth and quick start under different operating loads, reducing clutch wear. It allows the transmission to adapt to different boost rates under various operating loads, reducing clutch slippage and improving efficiency and reliability.

[0088] Specifically, the starting method in this embodiment includes: according to the mechanical 1st or 2nd gear, high or low gear selected by the operating unit, energizing the synchronizer solenoid valve (synchronizer switching valve) corresponding to the target gear for gear engagement; then opening the clutch switching valve signal of the target clutch corresponding to the selected power gear; and then, by controlling the clutch proportional valve of the corresponding target clutch, applying a pre-engagement pressure value of 1.5-2.5 bar within 0.3-0.8 seconds to drive the driven wheel of the clutch to move slightly. This prevents the driving and driven teeth from jamming and failing to engage if the spline of the driving tooth is not aligned with the spline groove of the driven tooth, which is beneficial for the synchronization of the rear end. The system combines the components and applies a calibrated starting pressure, gradually increasing the pressure at a rate of 3-4 bar / s (first predetermined pressure rate) to allow the vehicle to start moving smoothly. Once the speed sensor n1 detects that the speed has reached a predetermined value (10-20 rpm), the pressure is increased rapidly at a rate of 6-7 bar / s (second predetermined pressure rate) to reduce clutch slippage time. During this process, based on the transmission ratio, if the speed difference between the primary and driven wheels of the clutch is less than a predetermined first threshold (20-30 rpm), the pressure is quickly increased to the working pressure, minimizing the high-wear slippage stage of the clutch. The above preferred embodiment achieves a smoother and faster start, reducing clutch wear.

[0089] Taking first gear as an example, the starting control logic works as follows: After the engine speed is controlled to the predetermined speed (1000 rpm), the solenoid valves corresponding to the second synchronizer 28 and the third synchronizer 29 operate. After the second-stage mechanical gear is engaged, the electro-hydraulic proportional directional valve K2 is controlled to apply an initial pressure of 1.5 bar (specific value depends on the calibration value) to the first gear clutch 26 within 0.3 seconds, generating a creep, which is beneficial for the synchronizer to engage. While monitoring the intermediate shaft speed sensor n1 in real time, the control logic controls the electro-hydraulic proportional directional valve K2 to smoothly pressurize the first gear clutch 26 at a speed of 3 bar / s. During this period, when the speed value of the speed sensor n1 is detected to rise from 0 to 10 rpm, the original pressurization is interrupted. The logic is to apply pressure at 6 bar / s (the specific value depends on the calibration) based on the pressure at the time of interruption. During this period, the speed value on the first gear 5 is calculated based on the speed and speed ratio output by the speed sensor n1: (n1)X(Z12 / Z5). This value is compared with the speed of the clutch driven part and the speed of the engine part (engine speed - speed of the first gear 5). Once the speed difference is less than 20 rpm, the original pressure application logic is immediately interrupted and the working pressure is applied directly. This closed-loop adaptive control method enables the vehicle to achieve smooth and quick start under different working conditions and loads, reduces clutch wear, and improves the ability to withstand heavy loads.

[0090] In this embodiment and some other embodiments, the clutch power gear upshift control method specifically includes the following steps:

[0091] B1. Control the clutch proportional valve to give the target clutch a pre-engagement pressure value and open the clutch switching valve of the target clutch.

[0092] B2. Control the clutch proportional valve of the current clutch to reduce the pressure to the pre-engagement pressure value within a predetermined time to complete the gear shift. The current clutch refers to the clutch corresponding to the current gear.

[0093] B3. Close the clutch switch valve and clutch proportional valve of the current clutch, and control the clutch proportional valve to apply pressure to the target clutch smoothly at the third predetermined pressure rate.

[0094] B4. When the speed sensor n1 is detected to have reached a predetermined value, the target clutch in the clutch assembly is pressurized at a higher fourth predetermined pressure rate.

[0095] B5. Based on the detection value of speed sensor n1, the speed value on the driven gear of the target clutch is obtained; based on the engine speed value, the speed value of the driving wheel of the target clutch is obtained. When the difference between the speed value on the driven gear of the target clutch and the speed value of the driving wheel of the target clutch is less than a second threshold (predetermined threshold), the proportional valve is controlled to directly pressurize the target clutch to the working pressure value, so that it is fully engaged, thereby realizing the synchronous rotation of the driving wheel and the driven gear of the clutch. Specifically, the power gear upshift (clutch switching upshift) control method in this embodiment includes:

[0096] First, the clutch proportional valve corresponding to the target gear applies an initial pressure of 1.5-2.5 bar (pre-engagement pressure value) to the target clutch, and the clutch switching valve of the target clutch is opened. Then, the current of the clutch proportional valve of the current gear is controlled to gradually reduce the pressure to 1.5-2.5 bar (first predetermined pressure value) within 0.5-1 seconds. This setting avoids the power interruption and jerking caused by the sudden disengagement of the current clutch during gear shifting, and also avoids the shock that may occur when the target clutch suddenly engages. After the two gears switch at this pressure position, the proportional valve and switching valve of the current gear close, and the proportional valve of the target gear is controlled to apply pressure to the corresponding clutch at a rate of 3-4 bar / s (third predetermined pressure rate), so that the vehicle's power system can accelerate smoothly and avoid vehicle jerking caused by excessive engagement. When the speed sensor n1 detects that it has started to accelerate to a predetermined value (reaching a speed of 10-20 rpm), the original pressure-boosting subroutine is interrupted. Starting from the pressure at the time of interruption, pressure is increased at a rate of 6-7 bar / s (the fourth predetermined pressure rate, the specific value depending on calibration). Pressure is increased based on the actual vehicle response (the detection value of speed sensor n1), ensuring smooth and efficient gear shifting under different operating conditions. By increasing the pressure rate, the overall gear shifting time can be shortened, reducing the overall clutch slippage time. During this process, the speed value calculated from the speed sensor n1's rotational speed and speed ratio onto the corresponding clutch driven gear is compared with the engine speed as the clutch's active speed. Once the speed difference is less than 20-30 rpm (the second threshold), the original pressure-boosting logic is immediately interrupted, and working pressure is applied directly, minimizing the high-wear slippage stage of the clutch. The above preferred embodiment achieves smoother and faster upshifts, reducing clutch wear.

[0097] Taking the shift from 2nd to 3rd gear as an example, the power shift control logic first energizes the solenoid valve K4, controlling the electro-hydraulic proportional valve K2 to build an initial pressure of 1.5 bar for the third-gear clutch 24. Simultaneously, the electro-hydraulic proportional valve K1 controls the second-gear clutch 25 to depressurize. When the pressure drops to 1.5 bar within approximately 0.5 seconds, both electro-hydraulic proportional valves K1 and K2 quickly close. The electro-hydraulic proportional directional valve K2 then pressurizes the third-gear clutch 24 at a rate of 3 bar / s. When the speed sensor n1 detects that the speed has started to increase to 10-20 rpm, the original pressure increase is interrupted. The subroutine applies pressure at 6 bar / s (the specific value depends on the calibration) based on the pressure at the time of interruption. During this process, the speed value on the third gear 3 is calculated based on the speed sensor n1 and the speed ratio: (n1)X(Z9 / Z3). This value is compared with the speed of the clutch driven part and the speed of the engine part (engine speed - speed of the third gear 3). Once the speed difference is less than 20 rpm, the original pressure application logic is immediately interrupted and the working pressure is applied directly. This closed-loop dynamic adaptive control method reduces slip friction loss and ensures smooth and fast gear shifting.

[0098] In this embodiment and some other embodiments, the clutch power gear downshift control method specifically includes the following steps:

[0099] C1. Open the clutch switch valve of the target clutch, control the clutch proportional valve to give the target clutch a pre-engagement pressure value, and at the same time control the clutch proportional valve to reduce the pressure of the current clutch within a predetermined time, where the current clutch refers to the clutch corresponding to the current gear.

[0100] C2. After the current clutch drops to the pre-engagement pressure value, quickly close the switching valve and proportional valve of the current clutch, and control the proportional valve of the target clutch to pressurize the target clutch at the fifth predetermined pressure rate.

[0101] C3. Based on the detection value of the speed sensor n1, obtain the speed value of the driven gear of the target clutch; based on the engine speed value, obtain the speed value of the driving wheel of the target clutch; and control the engine speed to approach the speed of the driven gear of the target clutch.

[0102] C4. When the difference between the speed value on the driven gear of the target clutch and the speed of the driving gear of the target clutch is less than the third threshold (predetermined threshold), the control proportional valve directly pressurizes the target clutch to the working pressure value, so that the target clutch is fully engaged.

[0103] C5. When the target clutch is fully engaged, the engine throttle speed is restored, which can both reduce speed smoothly and significantly reduce clutch wear.

[0104] This closed-loop control method for engine control significantly reduces slippage and achieves smooth and rapid gear shifting. After the gear shift is completed, the engine is controlled to return to the throttle control speed.

[0105] Specifically, the power gear downshift (clutch switching downshift) control method in this embodiment includes the following steps:

[0106] The power downshift control first energizes the clutch switch valve of the target clutch, controlling the corresponding proportional valve to apply an initial pressure of 1.5-2.5 bar to the clutch. Simultaneously, the proportional valve of the current gear reduces the pressure of the current clutch to 1.5-2.5 bar (the second predetermined pressure value) within approximately 0.5-1 second. Then, the switch valve and proportional valve of the current gear are quickly closed, and the proportional valve of the target clutch is controlled to pressurize the clutch at a rate of 2-3 bar / s (the fifth predetermined pressure rate). Based on the detected speed of speed sensor n1 and the corresponding power gear ratio, the speed of the clutch driven gear is calculated. Using this speed as a reference, the engine speed is controlled to reach the speed of the clutch driving wheel. Once the speed difference between the clutch driving and driven wheels is less than the third threshold (20-30 rpm), the original pressurization logic is immediately interrupted, and the working pressure is directly applied. Once the target clutch is fully engaged, the engine throttle speed is restored. This minimizes the high-wear slippage stage of the clutch. The above preferred embodiment achieves smoother and faster downshifting, significantly reducing clutch wear.

[0107] Taking the downshift from 3rd to 2nd gear as an example, the power downshift control logic first controls the electro-hydraulic proportional valve K1 to establish an initial pressure of 1.5 bar for the second-gear clutch 25. At the same time, it controls the electro-hydraulic proportional directional valve K2 of the third gear to reduce the pressure of the third-gear clutch 24. When the pressure drops to 1.5 bar within about 0.5 seconds, the electro-hydraulic proportional valve K2 and the solenoid switch valve K4 close rapidly. The electro-hydraulic proportional directional valve K1 pressurizes the second-gear clutch 25 at a speed of 2 bar / s. Based on the detected speed of the speed sensor n1 and the corresponding power second gear ratio, the speed of the driven gear of the second-gear clutch 25, i.e., the power second gear 4, is calculated as (n1) x (Z11 / Z4). Using this speed as a reference, the engine speed is controlled to the speed of the driving wheel of the second-gear clutch 25. Once the speed difference between the driving and driven wheels of the clutch is less than 20 rpm, the original pressurization logic is immediately interrupted, and the working pressure is directly applied. When the target clutch is fully engaged, the engine throttle control speed is restored. This closed-loop control method of engine linkage significantly reduces slip friction loss and achieves smooth and fast downshifting.

[0108] In this embodiment and some other embodiments, during gear shifting in operating conditions, the pressure value for switching between the current clutch and the target clutch is 6.5-8 bar, while the shifting pressure value during road conditions is 1.5-2.5 bar. The engine load data shows a load rate exceeding a preset ratio, and this state is stably maintained for a predetermined time without interruption; this is considered the operating condition. In this embodiment, because the load on the tractor differs significantly between road driving and operating driving, the shifting pressure during power gear shifting is noticeably different. First, engine load data is sampled; if the load rate exceeds 50%, and this state is stably maintained for more than 20 seconds, this is considered the operating condition. During gear shifting, the pressure value for switching between the current gear clutch and the target gear clutch is 6.5-8 bar, while the shifting pressure value during road conditions is 1.5-2.5 bar, to ensure uninterrupted power during power gear shifting and maintain smoothness.

[0109] In this embodiment and some other embodiments, the shifting and upshifting control method of the synchronizer mechanical gear specifically includes the following steps:

[0110] D1. Control the proportional valve of the current clutch to reduce the pressure of the current clutch to a first predetermined pressure value, where the current clutch refers to the clutch corresponding to the current gear.

[0111] D2. Close the synchronizer switch valve corresponding to the current gear, and open the synchronizer switch valve corresponding to the target gear to shift gears;

[0112] D3. After the mechanical gear synchronizer completes the shift, the proportional valve of the current clutch is pressurized to the second predetermined pressure value within a predetermined time, and then pressurized at the sixth predetermined pressure rate. When the speed sensor n1 is detected to have reached the predetermined value, the pressure is increased at a higher seventh predetermined pressure rate.

[0113] D4. Based on the detection value of speed sensor n1, the speed value on the driven gear of the target clutch is obtained. Based on the engine speed value, the speed value of the driving wheel of the target clutch is obtained. When the difference between the speed value on the driven gear of the front clutch and the speed value of the driving wheel of the target clutch is less than the fourth threshold (predetermined threshold), the proportional valve is controlled to directly pressurize the current clutch to the working pressure value so that it is fully engaged, thereby realizing the synchronous rotation of the driving wheel and the driven gear of the clutch. The current clutch is the target clutch.

[0114] In this embodiment, the shifting and upshifting control method for a mechanical gearbox specifically includes the following steps:

[0115] For mechanical gear shifting and upshifting control during driving, first control the proportional valve of the clutch corresponding to the current power gear to reduce the clutch pressure to 1-2 bar (first predetermined pressure value). Then, control the closing of the solenoid valve (synchronizer switching valve) of the synchronizer corresponding to the current mechanical gear and open the switching valve of the synchronizer corresponding to the target gear to perform synchronizer shifting. Then, control the proportional valve of the current power gear to pressurize to 2-3 bar (second predetermined pressure value) within 0.3-0.8 seconds. Low-pressure micro-motion facilitates reliable synchronizer engagement. Then, pressurize at a rate of 4-5 bar / s (sixth predetermined pressure rate). During this process, if the speed sensor... When n1 reaches a predetermined value as the pressurization rate increases (reaching a speed of 10-20 rpm), the original pressurization logic is interrupted. Based on the pressure at the time of interruption, pressurization is increased at a rate of 6 bar / s (the seventh predetermined pressure rate, the specific value depends on the calibration). During this period, the speed value on the current power gear is calculated based on the rotational speed and speed ratio of the speed sensor n1. This speed is compared with the speed of the clutch driven part and the engine speed as the speed of the clutch driving part. Once the speed difference is less than the fourth threshold (15-25 rpm), the original pressurization logic is immediately interrupted, and the working pressure is directly applied. This can minimize the high wear and slippage stage of the clutch.

[0116] Shifting between mechanical and high / low gears, taking shifting from mechanical 1st to 2nd gear in 2nd power gear as an example, first control the electro-hydraulic proportional directional valve K1 of the current power gear to reduce the clutch pressure to 1-2 bar. Then, control the closing of the mechanical 1st gear solenoid valve K6 and the opening of the 2nd gear solenoid valve K5 to perform synchronizer shifting. Finally, control the current power gear electro-hydraulic proportional valve K1 to pressurize to 2-3 bar within 0.3-0.8 seconds. The low-pressure micro-motion facilitates reliable gear engagement of the second synchronizer 28, and then increases the pressure at a rate of 4-5 bar / s. During this period, if the speed sensor n1 reaches a speed of 10-20 rpm as the pressure increases, the original pressure increase logic is interrupted, and the pressure is increased from the pressure at the time of interruption at a rate of 6-7 bar / s (the specific value depends on the calibration). During this period, the speed value (n1)X(Z11 / Z4) on the second gear 4 is calculated based on the speed and speed ratio of the speed sensor n1 and compared with the speed of the clutch driven part and the speed of the engine part. Once the speed difference is less than 20 rpm, the original pressure increase logic is immediately interrupted, and the working pressure is directly applied. This closed-loop dynamic adaptive control method can realize mechanical gear shifting without stopping and smoothly and quickly complete the gear shift.

[0117] In this embodiment and some other embodiments, the method for controlling downshifting during travel of the synchronizer mechanical gear specifically includes the following steps:

[0118] E1. Control the proportional valve of the current clutch to reduce the pressure of the current clutch to the third predetermined pressure value, where the current clutch refers to the clutch corresponding to the current gear.

[0119] E2. Close the synchronizer switch valve corresponding to the current gear, and open the synchronizer switch valve corresponding to the target gear to shift gears.

[0120] E3. After the mechanical gear synchronizer completes the shift, the proportional valve of the current clutch is pressurized to the fourth predetermined pressure value within a predetermined time. The engine speed value is obtained. Based on the detection value of the speed sensor n1, the speed value on the driven gear of the target clutch is obtained, and the engine speed is controlled to increase to the same speed.

[0121] E4. When the difference between the speed value on the driven gear of the target clutch and the engine speed value is less than the fifth threshold, the control proportional valve directly pressurizes the target clutch to the working pressure value, so that it is fully engaged, thereby realizing the synchronous rotation of the clutch driving wheel and the clutch driven gear.

[0122] E5. Once the target clutch is fully engaged, control the engine speed to return to the throttle speed.

[0123] In this embodiment, the method for controlling downshifting while driving using a mechanical gearbox specifically includes the following steps:

[0124] First, control the proportional valve of the current power gear to reduce the clutch pressure to 1-2 bar (the third predetermined pressure value). Then, control the solenoid valve (synchronizer switch valve) of the current mechanical gear to close and open the control valve of the synchronizer corresponding to the target gear to perform synchronizer shifting. Then, control the proportional valve of the current power gear to pressurize to 2-3 bar (the fourth predetermined pressure value) within 0.3-0.8 seconds. Low-pressure micro-motion facilitates reliable synchronizer shifting. Then, according to the transmission structure of the mechanical target gear, the speed of speed sensor n1 is converted to the speed on the driven gear of the clutch, and the engine speed is controlled to increase to the same speed. Once the speed difference between the clutch master and driven wheels is less than the fifth threshold (20-30 rpm) and close to synchronization, the pressure is quickly increased to the working pressure to make the clutch engage quickly and smoothly. After the shift is completed, the engine speed is controlled to return to the throttle speed. This closed-loop control method of the engine effectively reduces clutch wear.

[0125] For shifting between mechanical and high / low gears, taking the shift from mechanical 2nd gear to 1st gear in power 2nd gear as an example, first, control the electro-hydraulic proportional valve K1 of the current power gear to reduce the clutch pressure to 1 bar. Then, control the closing of the mechanical 2nd gear solenoid switch valve K5 and the opening of the 1st gear solenoid switch valve K6 to perform synchronizer shifting. Then, control the current power gear proportional valve to pressurize to 2 bar within 0.3 seconds. Low-pressure micro-motion facilitates reliable synchronizer engagement. Then, according to the transmission structure of mechanical 1st gear, the speed of speed sensor n1 is converted to the speed of the driven gear of 1st gear clutch 26, i.e., the power 1st gear gear 5. Control the engine speed to increase to the same speed. Once the speed difference between the main and driven wheels of 1st gear clutch 26 is less than 20 rpm, after approaching synchronization, quickly pressurize to the working pressure to make 1st gear clutch 26 engage quickly and smoothly. After the shift is completed, control the engine speed to return to the throttle speed. This closed-loop control method of the engine effectively reduces clutch wear.

[0126] In this embodiment and some other embodiments, the power gears on the input shaft component include: a fourth-speed gear 2, a third-speed gear 3, a second-speed gear 4, and a first-speed gear 5. The clutches include: a fourth-speed clutch 23, a third-speed clutch 24, a second-speed clutch 25, and a first-speed clutch 26. The engine is connected to the left side of the input shaft A. The fourth-speed gear 2, the third-speed gear 3, the second-speed gear 4, and the first-speed gear 5 are loosely fitted onto the input shaft A. The fourth-speed gear 2 can be connected to the input shaft A and rotate synchronously through the fourth-speed clutch 23. The third-speed gear 3 can be connected to the input shaft A and rotate synchronously through the third-speed clutch 24. The second-speed gear 4 can be connected to the input shaft A and rotate synchronously through the second-speed clutch 25. The first-speed gear 5 can be connected to the input shaft A and rotate synchronously through the first-speed clutch 26. By engaging and disengaging the fourth-speed clutch 23, the third-speed clutch 24, the second-speed clutch 25, and the first-speed clutch 26, control of four gears can be achieved.

[0127] The intermediate shaft component includes several gears mounted on the intermediate shaft B, including: a reverse gear 6, a first transmission gear 7, a second transmission gear 8, a third transmission gear 9, a fourth transmission gear 10, a fifth transmission gear 11, and a sixth transmission gear 12 mounted on the intermediate shaft B. The first transmission gear 7 meshes with the fourth power gear 2, the third transmission gear 9 meshes with the third power gear 3, the fifth transmission gear 11 meshes with the second power gear 4, and the sixth transmission gear 12 meshes with the first power gear 5.

[0128] The idler shaft assembly specifically includes: an idler shaft F and an idler wheel 14 loosely fitted on the idler shaft F, the idler wheel 14 meshing with the reverse gear 6 for transmission;

[0129] The synchronizer assembly mounted on the secondary transmission shaft C includes: a reverse gear 15, a mechanical first gear 16, a mechanical second gear 17, a first synchronizer 27, and a second synchronizer 28. The transmission gears include: an eighth transmission gear 18 and a seventh transmission gear 19. The reverse gear 15, mechanical first gear 16, and mechanical second gear 17 are loosely fitted onto the secondary transmission shaft C. The eighth transmission gear 18 and the seventh transmission gear 19 are fixedly fitted onto the secondary transmission shaft C. The first synchronizer 27 and the second synchronizer 28 are both mounted on the secondary transmission shaft C. The reverse gear 15 meshes with the idler gear 14 for transmission. The mechanical first gear... Gear 16 meshes with the second transmission gear 8, and mechanical second gear 17 meshes with the fourth transmission gear 10. Reverse gear 15 can be connected to the auxiliary transmission shaft C through the first synchronizer 27 and rotate synchronously. Mechanical first gear 16 and mechanical second gear 17 can be connected to the auxiliary transmission shaft C through the second synchronizer 28 and rotate synchronously. By shifting gears left and right through the second synchronizer 28, two gears can be controlled. By shifting gears through the first synchronizer 27, reverse gear can be achieved.

[0130] The output components specifically include: an output shaft G, a high-gear output gear 20, a low-gear output gear 21, and a third synchronizer 29. Both the high-gear output gear 20 and the low-gear output gear 21 are loosely fitted onto the output shaft G. The high-gear output gear 20 meshes with the eighth transmission gear 18, and the low-gear output gear 21 meshes with the seventh transmission gear 19. Two gear positions can be controlled by shifting left and right using the third synchronizer 29. The upshifting method for high and low gears is the same as the upshifting method for mechanical gears, and the downshifting method for high and low gears is the same as the downshifting method for mechanical gears. In this embodiment, with 4 gears in the input shaft component, 2 gears in the auxiliary transmission shaft component, and 2 gears in the front output component D, 4×2×2=16 forward gears can be achieved; with 4 gears in the input shaft component, 1 reverse gear in the auxiliary transmission shaft component, and 2 gears in the front output component D, 4×1×2=8 reverse gears can be achieved, meeting the needs of various terrains and operations.

[0131] Specifically, in this embodiment, the gearbox body further includes: a first gear cylinder 35, a second gear cylinder 36, a reverse gear cylinder 34, and a high / low gear cylinder 37. The hydraulic system includes a working oil pump 31, a main gear shift valve block S1, a secondary gear shift valve block S2, and a high / low gear valve block S3. The main gear shift valve block S1 includes an electro-hydraulic proportional directional valve K1, an electro-hydraulic proportional directional valve K2, a solenoid directional valve K3, and a solenoid directional valve K4. The secondary gear shift valve block S2 includes a solenoid directional valve K5. The system includes solenoid directional valves K6 and K7, and a high / low gear valve block S3 comprising solenoid directional valve K9, electro-hydraulic proportional directional valves K1 and K2 connected in parallel. The oil inlet of solenoid directional valve K4 is connected to the working oil pump 31 via electro-hydraulic proportional directional valve K2. The oil inlet of solenoid directional valve K3 is connected to the working oil pump 31 via electro-hydraulic proportional directional valve K1. The oil inlets of solenoid directional valves K5, K6, and K7, connected in parallel, are all connected to the working oil pump 31. The inlet of the solenoid directional valve K9 is connected to the working oil pump 31. The first gear clutch 26 and the third gear clutch 24 are respectively connected to the two working ports of the solenoid directional valve K4. The second gear clutch 25 and the fourth gear clutch 23 are respectively connected to the two working ports of the solenoid directional valve K3. The working port of the solenoid directional valve K5 is connected to the second gear cylinder 36. The working port of the solenoid directional valve K6 is connected to the first gear cylinder 35. The working port of the solenoid directional valve K7 is connected to the reverse gear cylinder. The working port of the solenoid directional valve K9 is connected to the high / low gear cylinder 37. The second gear cylinder 36 is used to push the second synchronizer 28 to engage with the mechanical first gear 16. The first gear cylinder 35 is used to push the second synchronizer 28 to engage with the mechanical second gear 17. The reverse gear cylinder 34 is used to push the first synchronizer 27 to engage with the reverse gear 15. The high / low gear cylinder 37 is used to push the third synchronizer 29 to engage with the low gear or to engage with the high gear output gear 20. The hydraulic unit's electro-hydraulic proportional directional valve K1 and solenoid directional valve K3 combine to control the second and fourth gear clutches 23, enabling the engagement of power second and fourth gears; the hydraulic unit's electro-hydraulic proportional directional valve K2 and solenoid directional valve K4 combine to control the first and third gear clutches 24, enabling the engagement of power first and third gears; the hydraulic unit's solenoid directional valves K5, K6, K7, and K9 respectively control the engagement of mechanical second, first, reverse, high, and low gears; the electro-hydraulic proportional directional valve K1 and the electro-hydraulic... The proportional directional valve K1 is a two-position three-way electro-hydraulic proportional directional valve; the solenoid directional valves K3 and K4 are two-position four-way solenoid directional valves; the solenoid directional valves K5, K6, and K7 are two-position three-way solenoid directional valves; and the solenoid directional valves K8 and K9 are two-position four-way solenoid directional valves. The two chambers of the high and low gear cylinder 37 are respectively connected to the two working ports of the solenoid directional valve K9, and the two chambers of the four-wheel drive cylinder 38 are respectively connected to the two working ports of the solenoid directional valve K8.A pressure sensor P is installed on the oil circuit connecting the working oil pump 31 to the main transmission gear position valve block S1, the auxiliary transmission gear position valve block S2, and the high and low gear position valve block S3. The pressure sensor P is connected to the control module. In this embodiment, the hydraulic system adopts a drive structure combining proportional valves and on / off valves to reduce costs while ensuring performance. The synchronizer mechanical shifting actuator is driven by an electro-hydraulic valve to complete the shifting, thus reducing costs while ensuring performance. The hydraulic system has a simple structure and can reduce the failure rate.

[0132] In this embodiment, the gearbox body also includes a four-wheel drive cylinder 38. In the gearbox body, one end of the output shaft G is fixedly connected to the front output component D, and the other end is fixedly connected to the front-wheel drive / four-wheel drive switching gear 30. A fourth synchronizer 22 is coaxially fixed and rotates synchronously with the rear output component E. The fourth synchronizer 22 is rotatably coaxially arranged with the front-wheel drive / four-wheel drive switching gear 30, and can engage with and rotate synchronously with the front-wheel drive / four-wheel drive switching gear 30. The hydraulic system includes a working oil pump 31 and a four-wheel drive valve block S4. The four-wheel drive valve block S4 includes a solenoid directional valve K8. The oil inlet of the solenoid directional valve K8 is connected to the working oil pump 31, and the working oil port is connected to the four-wheel drive cylinder 38. The four-wheel drive cylinder 38 is used to push the fourth synchronizer 22 to engage with the front-wheel drive / four-wheel drive switching gear 30. By disengaging and engaging the fourth synchronizer 22 with the front-wheel drive / four-wheel drive switching gear 30, it is possible to control whether the rear output component E has power output, that is, to control the front-wheel drive or four-wheel drive mode. The shifting actions of the first synchronizer 27, the second synchronizer 28, the third synchronizer 29, and the fourth synchronizer 22 are completed by the AMT shifting mechanism.

[0133] In this embodiment and some other embodiments, a temperature sensor is installed at the bottom of the transmission case to monitor the transmission oil temperature. If the temperature exceeds a predetermined temperature during vehicle operation, a warning is issued; if the temperature exceeds a safe level, power is interrupted, and the corresponding hydraulic valve is forcibly closed to disengage the clutch and protect it. If a malfunction is detected due to the temperature sensor or speed sensor itself, pressing the emergency start button activates the emergency start function, limiting engine speed and transmission gears to provide limited power transmission and ensure vehicle movement in special circumstances.

[0134] After shifting gears, the speed ratio is calculated based on the engine speed, power gear output speed, and overall machine output speed. This is compared with the theoretical speed ratio of the gear to be selected to determine the state of the transmission mechanism. If the calculated speed ratio changes beyond the error value during operation, it indicates that the clutch is slipping abnormally due to overload or other reasons. The system will immediately control the clutch to disengage and interrupt power, effectively protecting the clutch.

[0135] The power shift mechanism reduces costs by employing a combination of clutch switching valves and a clutch switching valve drive structure while maintaining performance. The synchronizer mechanical shift actuator is driven by an electro-hydraulic valve (synchronizer switching valve) that pushes a cylinder, further reducing costs while ensuring performance. Based on the transmission's mechanical and hydraulic characteristics, the control module combines engine speed, main transmission power output speed, and overall transmission output speed. Through closed-loop dynamic adaptive calculation, it controls the proportional valve pressure changes and coordinates with the engine, adapting to complex operating conditions to achieve smooth and quick starting and shifting, improving starting and shifting efficiency and adaptability, reducing clutch wear, and improving reliability. After gear engagement, the system uses the speed signal from speed sensor n1 and the engine speed signal to calculate the current gear and gear ratio, monitoring in real time. If abnormal slippage occurs, power is immediately cut off to protect the transmission and improve reliability. The system features several key features: engine speed signals are transmitted via CAN bus communication and received by the TCU; temperature monitoring is tiered, triggering alarms when temperatures exceed warning levels and immediately cutting off power to protect the transmission and improve reliability when temperatures exceed safe levels; an emergency start function is added, activating a limited vehicle home mode in case of power interruption due to a faulty temperature or speed sensor, preventing the vehicle from losing power and becoming immobile in special circumstances; engine load data is used to determine road and operating conditions, selecting different shift pressure values ​​to adapt to various load conditions and ensure smooth shifting; this invention achieves 16 forward gears + 8 reverse gears through electro-hydraulic power, and has been applied to the PT400 high-horsepower tractor, and can be applied to the transmissions of tractors of various horsepower ranges within the same power range.

[0136] The front-wheel drive and four-wheel drive control method of the hydraulic system in this embodiment is as follows:

[0137] 1. Front-drive mode: When the solenoid reversing valve K8 is de-energized, the four-wheel drive cylinder 38 controls the fourth synchronizer 22 to disengage from the front-drive / four-wheel drive switching gear 30, and the rear output component EE has no power output;

[0138] II. Four-wheel drive mode: When the solenoid reversing valve K8 is energized, the four-wheel drive cylinder 38 controls the fourth synchronizer 22 to engage with the front-wheel drive / four-wheel drive switching gear 30, and the rear output component EE has power output.

[0139] The forward gear control method of the hydraulic system in this embodiment is as follows:

[0140] 1. Forward 1st gear: 1. Electro-hydraulic proportional directional valve K2 is energized, controlling the engagement of the 1st gear clutch 26; 2. Solenoid directional valve K6 is energized, controlling the 1st gear cylinder 35 to push the second synchronizer 28 to engage with the mechanical 2nd gear 17; 3. Solenoid directional valve K9 is energized, controlling the high / low gear cylinder 37 to push the third synchronizer 29 to engage with the low gear output gear 21.

[0141] That is: power input → power first gear 5 → sixth transmission gear 12 → fourth transmission gear 10 → mechanical second gear 17 → seventh transmission gear 19 → low gear output gear 21 → power output front drive or four drive.

[0142] II. Forward 2nd gear: 1. Electro-hydraulic proportional directional valve K1 is energized, controlling the second gear clutch 25 to engage; 2. Solenoid directional valve K6 is energized, controlling the first gear cylinder 35 to push the second synchronizer 28 to engage with the mechanical second gear 17; 3. Solenoid directional valve K9 is energized, controlling the high / low gear cylinder 37 to push the third synchronizer 29 to engage with the low gear output gear 21.

[0143] That is: power input → power second gear 4 → fifth transmission gear 11 → fourth transmission gear 10 → mechanical second gear 17 → seventh transmission gear 19 → low gear output gear 21 → power output front drive or four drive.

[0144] III. Forward 3rd Gear 1. Electro-hydraulic proportional directional valve K2 is energized, and solenoid directional valve K4 is energized; controlling the engagement of the 3rd gear clutch 24; 2. Solenoid directional valve K6 is energized, controlling the 1st gear cylinder 35 to push the second synchronizer 28 to engage with the mechanical 2nd gear 17; 3. Solenoid directional valve K9 is energized, controlling the high / low gear cylinder 37 to push the third synchronizer 29 to engage with the low gear output gear 21;

[0145] That is: power input → power third gear 3 → third transmission gear 9 → fourth transmission gear 10 → mechanical second gear 17 → seventh transmission gear 19 → low gear output gear 21 → power output front drive or four drive.

[0146] IV. Forward 4th Gear: 1. Electro-hydraulic proportional directional valve K1 is energized, solenoid directional valve K3 is energized, controlling the engagement of the fourth gear clutch 23; 2. Solenoid directional valve K6 is energized, controlling the first gear cylinder 35 to push the second synchronizer 28 to engage with the mechanical second gear 17; 3. Solenoid directional valve K9 is energized, controlling the high / low gear cylinder 37 to push the third synchronizer 29 to engage with the low gear output gear 21;

[0147] That is: power input → power fourth gear 2 → first transmission gear 7 → fourth transmission gear 10 → mechanical second gear 17 → seventh transmission gear 19 → low gear output gear 21 → power output front drive or four drive.

[0148] V. Forward 5 gears: 1. Electro-hydraulic proportional directional valve K2 is energized, controlling the engagement of the first gear clutch 26; 2. Solenoid directional valve K5 is energized, controlling the second gear cylinder to push the second synchronizer 28 to engage with the mechanical first gear 16; 3. Solenoid directional valve K9 is energized, controlling the high / low gear cylinder 37 to push the third synchronizer 29 to engage with the low gear output gear 21.

[0149] That is: power input → power first gear 5 → sixth transmission gear 12 → second transmission gear 8 → mechanical first gear 16 → seventh transmission gear 19 → low gear output gear 21 → power output front drive or four drive.

[0150] VI. Forward 6th gear: 1. Electro-hydraulic proportional directional valve K1 is energized, controlling the second gear clutch 25 to engage; 2. Solenoid directional valve K5 is energized, controlling the second gear cylinder to push the second synchronizer 28 to engage with the mechanical first gear 16; 3. Solenoid directional valve K9 is energized, controlling the high / low gear cylinder 37 to push the third synchronizer 29 to engage with the low gear output gear 21.

[0151] That is: power input → power second gear 4 → fifth transmission gear 11 → second transmission gear 8 → mechanical first gear 16 → seventh transmission gear 19 → low gear output gear 21 → power output front drive or four drive.

[0152] VII. Forward 7th gear: 1. Electro-hydraulic proportional directional valve K2 is energized, and solenoid directional valve K4 is energized; controlling the engagement of the third gear clutch 24; 2. Solenoid directional valve K5 is energized, controlling the second gear cylinder to push the second synchronizer 28 to engage with the mechanical first gear 16; 3. Solenoid directional valve K9 is energized, controlling the high / low gear cylinder 37 to push the third synchronizer 29 to engage with the low gear output gear 21;

[0153] Power input → Power third gear 3 → Third transmission gear 9 → Second transmission gear 8 → Mechanical first gear 16 → Seventh transmission gear 19 → Low gear output gear 21 → Power output front drive or four drive.

[0154] 8. Forward 8th gear: 1. Electro-hydraulic proportional directional valve K1 is energized, solenoid directional valve K3 is energized, controlling the engagement of the fourth gear clutch 23; 2. Solenoid directional valve K5 is energized, controlling the second gear cylinder to push the second synchronizer 28 to engage with the mechanical first gear 16; 3. Solenoid directional valve K9 is energized, controlling the high / low gear cylinder 37 to push the third synchronizer 29 to engage with the low gear output gear 21;

[0155] That is: power input → power fourth gear 2 → first transmission gear 7 → second transmission gear 8 → mechanical first gear 16 → seventh transmission gear 19 → low gear output gear 21 → power output front drive or four drive.

[0156] 9. Forward 9th gear: 1. When the electro-hydraulic proportional directional valve K2 is energized, it controls the engagement of the first gear clutch 26; 2. When the solenoid directional valve K6 is energized, it controls the first gear cylinder 35 to push the second synchronizer 28 to engage with the mechanical second gear 17; 3. When the solenoid directional valve K9 is de-energized, it controls the high / low gear cylinder 37 to push the third synchronizer 29 to engage with the high gear output gear 20.

[0157] Power input → Power first gear 5 → Sixth transmission gear 12 → Fourth transmission gear 10 → Mechanical second gear 17 → Eighth transmission gear 18 → High gear output gear 20 → Power output front drive or four drive.

[0158] 10. Moving forward 10 gears: 1. The electro-hydraulic proportional directional valve K1 is energized, controlling the second gear clutch 25 to engage; 2. The solenoid directional valve K6 is energized, controlling the first gear cylinder 35 to push the second synchronizer 28 to engage with the mechanical second gear 17; 3. The solenoid directional valve K9 is de-energized, controlling the high / low gear cylinder 37 to push the third synchronizer 29 to engage with the high gear output gear 20.

[0159] Power input → Power second gear 4 → Fifth transmission gear 11 → Fourth transmission gear 10 → Mechanical second gear 17 → Eighth transmission gear 18 → High gear output gear 20 → Power output front drive or four drive.

[0160] 11. Moving forward to 11th gear: 1. Electro-hydraulic proportional directional valve K2 is energized, and solenoid directional valve K4 is energized; this controls the engagement of the third-gear clutch 24; 2. Solenoid directional valve K6 is energized, controlling the first-gear cylinder 35 to push the second synchronizer 28 to engage with the mechanical second-gear gear 17; 3. Solenoid directional valve K9 is de-energized, controlling the high / low gear cylinder 37 to push the third synchronizer 29 to engage with the high-gear output gear 20;

[0161] That is: power input → power third gear 3 → third transmission gear 9 → fourth transmission gear 10 → mechanical second gear 17 → eighth transmission gear 18 → high gear output gear 20 → power output front drive or four drive.

[0162] 12. Moving forward to 12th gear: 1. Electro-hydraulic proportional directional valve K1 is energized, solenoid directional valve K3 is energized, controlling the engagement of the fourth gear clutch 23; 2. Solenoid directional valve K6 is energized, controlling the first gear cylinder 35 to push the second synchronizer 28 to engage with the mechanical second gear 17; 3. Solenoid directional valve K9 is de-energized, controlling the high / low gear cylinder 37 to push the third synchronizer 29 to engage with the high gear output gear 20;

[0163] That is: power input → power fourth gear 2 → first transmission gear 7 → fourth transmission gear 10 → mechanical second gear 17 → eighth transmission gear 18 → high gear output gear 20 → power output front drive or four drive.

[0164] 13. Forward 13th gear: 1. Electro-hydraulic proportional directional valve K2 is energized, controlling the first gear clutch 26 to engage; 2. Solenoid directional valve K5 is energized, controlling the second gear cylinder to push the second synchronizer 28 to engage with the mechanical first gear 16; 3. Solenoid directional valve K9 is de-energized, controlling the high and low gear cylinder 37 to push the third synchronizer 29 to engage with the high gear output gear 20.

[0165] That is: power input → power first gear 5 → sixth transmission gear 12 → second transmission gear 8 → mechanical first gear 16 → eighth transmission gear 18 → high gear output gear 20 → power output front drive or four drive.

[0166] XIV. Forward 14th gear: 1. Electro-hydraulic proportional directional valve K1 is energized, controlling the second gear clutch 25 to engage; 2. Solenoid directional valve K5 is energized, controlling the second gear cylinder to push the second synchronizer 28 to engage with the mechanical first gear 16; 3. Solenoid directional valve K9 is de-energized, controlling the high and low gear cylinder 37 to push the third synchronizer 29 to engage with the high gear output gear 20.

[0167] That is: power input → power second gear 4 → fifth transmission gear 11 → second transmission gear 8 → mechanical first gear 16 → eighth transmission gear 18 → high gear output gear 20 → power output front drive or four drive.

[0168] 15. Moving forward to 15 gears: 1. Electro-hydraulic proportional directional valve K2 is energized, and solenoid directional valve K4 is energized; this controls the engagement of the third-gear clutch 24; 2. Solenoid directional valve K5 is energized, controlling the second-gear cylinder to push the second synchronizer 28 to engage with the mechanical first-gear gear 16; 3. Solenoid directional valve K9 is de-energized, controlling the high / low gear cylinder 37 to push the third synchronizer 29 to engage with the high-gear output gear 20;

[0169] That is: power input → power third gear 3 → third transmission gear 9 → second transmission gear 8 → mechanical first gear 16 → eighth transmission gear 18 → high gear output gear 20 → power output front drive or four drive.

[0170] XVI. Moving forward to 16 gears: 1. Electro-hydraulic proportional directional valve K1 is energized, solenoid directional valve K3 is energized, controlling the engagement of the fourth gear clutch 23; 2. Solenoid directional valve K5 is energized, controlling the second gear cylinder to push the second synchronizer 28 to engage with the mechanical first gear 16; 3. Solenoid directional valve K9 is de-energized, controlling the high / low gear cylinder 37 to push the third synchronizer 29 to engage with the high gear output gear 20;

[0171] That is: power input → power fourth gear 2 → first transmission gear 7 → second transmission gear 8 → mechanical first gear 16 → eighth transmission gear 18 → high gear output gear 20 → power output front drive or four drive.

[0172] The reverse gear control method of the hydraulic system in this embodiment is as follows:

[0173] 1. Reverse 1st gear: 1. Electro-hydraulic proportional directional valve K2 is energized, controlling the first gear clutch 26 to engage; 2. Solenoid directional valve K7 is energized, controlling the reverse gear cylinder 34 to push the first synchronizer 27 to engage the reverse gear 15; 3. Solenoid directional valve K9 is energized, controlling the high / low gear cylinder 37 to push the third synchronizer 29 to engage the low gear output gear 21.

[0174] That is: power input → first gear 5 → sixth transmission gear 12 → reverse transmission gear 6 → idler gear 14 → reverse gear 15 → seventh transmission gear 19 → low gear output gear 21 → power output front drive or four drive.

[0175] II. Reverse 2 gears: 1. Electro-hydraulic proportional directional valve K1 is energized, controlling the second gear clutch 25 to engage; 2. Solenoid directional valve K7 is energized, controlling the reverse gear cylinder 34 to push the first synchronizer 27 to engage the reverse gear 15; 3. Solenoid directional valve K9 is energized, controlling the high / low gear cylinder 37 to push the third synchronizer 29 to engage the low gear output gear 21.

[0176] That is: power input → second gear 4 → fifth transmission gear 11 → reverse transmission gear 6 → idler gear 14 → reverse gear 15 → seventh transmission gear 19 → low gear output gear 21 → power output front drive or four drive.

[0177] III. Reverse 3rd gear: 1. Electro-hydraulic proportional directional valve K2 is energized, and solenoid directional valve K4 is energized; controlling the engagement of the third gear clutch 24; 2. Solenoid directional valve K7 is energized, controlling the reverse gear cylinder 34 to push the first synchronizer 27 to engage with the reverse gear 15; 3. Solenoid directional valve K9 is energized, controlling the high / low gear cylinder 37 to push the third synchronizer 29 to engage with the low gear output gear 21;

[0178] That is: power input → power third gear 3 → third transmission gear 9 → reverse transmission gear 6 → idler gear 14 → reverse gear 15 → seventh transmission gear 19 → low gear output gear 21 → power output front drive or four drive.

[0179] IV. Reverse 4th gear 1. Electro-hydraulic proportional directional valve K1 is energized, solenoid directional valve K3 is energized, controlling the engagement of the fourth gear clutch 23; 2. Solenoid directional valve K7 is energized, controlling the reverse gear cylinder 34 to push the first synchronizer 27 to engage with the reverse gear 15; 3. Solenoid directional valve K9 is energized, controlling the high / low gear cylinder 37 to push the third synchronizer 29 to engage with the low gear output gear 21;

[0180] That is: power input → power fourth gear 2 → first transmission gear 7 → reverse transmission gear 6 → idler gear 14 → reverse gear 15 → seventh transmission gear 19 → low gear output gear 21 → power output front drive or four drive.

[0181] V. Reverse 5 gears: 1. Electro-hydraulic proportional directional valve K2 is energized, controlling the first gear clutch 26 to engage; 2. Solenoid directional valve K7 is energized, controlling the reverse gear cylinder 34 to push the first synchronizer 27 to engage the reverse gear 15; 3. Solenoid directional valve K9 is de-energized, controlling the high / low gear cylinder 37 to push the third synchronizer 29 to engage the high gear output gear 20.

[0182] That is: power input → first gear 5 → sixth transmission gear 12 → reverse transmission gear 6 → idler gear 14 → reverse gear 15 → eighth transmission gear 18 → high gear output gear 20 → power output front drive or four drive.

[0183] VI. Reverse 6th gear 1. Electro-hydraulic proportional directional valve K1 is energized, controlling the second gear clutch 25 to engage; 2. Solenoid directional valve K7 is energized, controlling the reverse gear cylinder 34 to push the first synchronizer 27 to engage the reverse gear 15; 3. Solenoid directional valve K9 is de-energized, controlling the high and low gear cylinder 37 to push the third synchronizer 29 to engage the high gear output gear 20;

[0184] That is: power input → second gear 4 → fifth transmission gear 11 → reverse transmission gear 6 → idler gear 14 → reverse gear 15 → eighth transmission gear 18 → high gear output gear 20 → power output front drive or four drive.

[0185] VII. Reverse 7th gear 1. Electro-hydraulic proportional directional valve K2 is energized, solenoid directional valve K4 is energized; control the third gear clutch 24 to engage; 2. Solenoid directional valve K7 is energized, control the reverse gear cylinder 34 to push the first synchronizer 27 to engage with the reverse gear 15; 3. Solenoid directional valve K9 is de-energized, control the high and low gear cylinder 37 to push the third synchronizer 29 to engage with the high gear output gear 20;

[0186] That is: power input → power third gear 3 → third transmission gear 9 → reverse transmission gear 6 → idler gear 14 → reverse gear 15 → eighth transmission gear 18 → high gear output gear 20 → power output front drive or four drive.

[0187] 8. Reverse 8 gears: 1. Electro-hydraulic proportional directional valve K1 is energized, solenoid directional valve K3 is energized, controlling the engagement of the fourth gear clutch 23; 2. Solenoid directional valve K7 is energized, controlling the reverse gear cylinder 34 to push the first synchronizer 27 to engage the reverse gear 15; 3. Solenoid directional valve K9 is de-energized, controlling the high / low gear cylinder 37 to push the third synchronizer 29 to engage the high gear output gear 20;

[0188] That is: power input → power fourth gear 2 → first transmission gear 7 → reverse transmission gear 6 → idler gear 14 → reverse gear 15 → eighth transmission gear 18 → high gear output gear 20 → power output front drive or four drive.

[0189] This gearbox structure can achieve 4×2×2=16 forward gears through the arrangement and combination of 4 gears in the input shaft component A, 2 gears in the auxiliary transmission shaft component C, and 2 gears in the front output component D;

[0190] The gearbox structure can achieve 4×1×2=8 reverse gears through the arrangement of 4 gears in the input shaft component A, 1 reverse gear in the auxiliary transmission shaft component C, and 2 gears in the front output component D.

[0191] The above description provides a further detailed explanation of the present invention in conjunction with specific / preferred embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the concept of the present invention, and all such substitutions or modifications should be considered within the scope of protection of the present invention. In the description of this specification, the reference to terms such as "an embodiment," "some embodiments," "preferred embodiment," "example," "specific example," or "some examples," etc., indicates that the specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. A control method for a transmission combining power shift and electro-hydraulic mechanical shift, characterized in that, The gearbox includes: an input shaft assembly, an intermediate shaft assembly, a secondary transmission shaft assembly, an idler gear shaft assembly, and an output shaft assembly; The input shaft assembly includes an input shaft A, several clutches mounted on the input shaft A, and a power shift gear that serves as the driven gear of the clutches. Power is transmitted from the input shaft A to the intermediate shaft assembly through the clutches and the power shift gear. The clutches are controlled by a clutch switching valve and a clutch proportional valve. The engine outputs power to the input shaft A. The driving wheel of the clutch is fixedly connected to the input shaft A and rotates synchronously. The intermediate shaft assembly includes an intermediate shaft B and several gears mounted on the intermediate shaft B, which are used to transmit power to the idler shaft assembly or the secondary transmission shaft assembly at different speeds. A speed sensor n1 is mounted on the intermediate shaft assembly. The idler shaft assembly includes an idler shaft F and an idler wheel mounted on the idler shaft F, used to change the transmission direction of the gears on the secondary transmission shaft assembly; The auxiliary transmission shaft assembly includes an auxiliary transmission shaft C and a synchronizer group and transmission gears disposed on the auxiliary transmission shaft C. The synchronizer group includes several synchronizers and gears corresponding to the synchronizers, used to switch different gears and transmit power to the output shaft assembly. The synchronizers are controlled by synchronizer switching valves. The output shaft assembly includes an output shaft G, which is used to output torque and speed to the wheels to drive the vehicle; It is also equipped with a temperature sensor to monitor the oil temperature inside the transmission. During vehicle operation, if the temperature exceeds the preset limit, a warning will be given. If the temperature exceeds the safe limit, power will be interrupted and the corresponding hydraulic valve of the clutch will be closed to disengage the clutch. The control method includes the following steps: S1. Control the clutch proportional valve to apply a pre-engagement pressure value to the target clutch, where the target clutch refers to the clutch to be engaged with the clutch driven gear; S2. Apply pressure to the target clutch to control the speed of the target clutch to approach the speed of the engine, or adjust the speed of the engine to approach the speed of the target clutch. S3. Based on the detection value of the speed sensor n1, the speed value of the driven gear of the target clutch is obtained, and based on the engine speed value, the speed value of the driving wheel of the target clutch is obtained. When the difference between the speed value of the driven gear of the target clutch and the speed value of the driving wheel of the target clutch is less than a predetermined threshold, the proportional valve is controlled to directly pressurize the target clutch to the working pressure value, so that it is fully engaged, thereby realizing the synchronous rotation of the driving wheel of the clutch and the driven gear of the clutch.

2. The control method for a transmission combining power shifting and electro-hydraulic mechanical shifting as described in claim 1, characterized in that, When starting or shifting up, step S2 includes: first pressurizing the target clutch at a pressurization rate, and if the detection value of speed sensor n1 reaches a predetermined value, pressurizing the target clutch at a higher pressurization rate.

3. The control method for a gearbox combining power shifting and electro-hydraulic mechanical shifting as described in claim 2, characterized in that, The predetermined value mentioned in step S2 is 10-20 rpm, and the predetermined threshold mentioned in step S3 is 20-30 rpm.

4. The control method for a transmission combining power shifting and electro-hydraulic mechanical shifting as described in claim 2, characterized in that, The start-up control method specifically includes the following steps: A1. Open the synchronizer switch valve corresponding to the target gear; A2. Open the clutch switch valve of the target clutch; A3. Open the clutch proportional valve of the target clutch and apply a pre-engagement pressure value within a predetermined time to drive the clutch driven wheel to move slightly, in order to promote the engagement of the rear synchronizer. A4. Control the clutch proportional valve of the target clutch to apply a calibrated effective starting pressure to the target clutch and gradually increase the pressure at the first predetermined pressure rate; A5. When the detection value of speed sensor n1 reaches the predetermined value, pressurize the target clutch at a higher second predetermined pressure rate; A6. The speed value on the driven gear of the target clutch is obtained based on the detection value of the speed sensor n1, and the speed value of the driving wheel of the target clutch is obtained based on the engine speed value. When the difference between the speed value on the driven gear of the target clutch and the speed value of the driving wheel of the target clutch is less than the first threshold, the proportional valve is controlled to directly pressurize the target clutch to the working pressure value so that it is fully engaged, thereby realizing the synchronous rotation of the driving wheel and the driven gear of the clutch.

5. The control method for a transmission combining power shifting and electro-hydraulic mechanical shifting as described in claim 2, characterized in that, The clutch power gear upshift control method specifically includes the following steps: B1. Control the clutch proportional valve to give the target clutch a pre-engagement pressure value and open the clutch switching valve of the target clutch. B2. Control the clutch proportional valve of the current clutch to reduce the pressure to the pre-engagement pressure value within a predetermined time to complete the gear shift. The current clutch refers to the clutch corresponding to the current gear. B3. Close the clutch switch valve and clutch proportional valve of the current clutch, and control the clutch proportional valve to apply pressure to the target clutch smoothly at the third predetermined pressure rate. B4. When the speed sensor n1 is detected to have reached a predetermined value, the target clutch in the clutch assembly is pressurized at a higher fourth predetermined pressure rate. B5. Based on the detection value of speed sensor n1, the speed value on the driven gear of the target clutch is obtained, and based on the engine speed value, the speed value of the driving wheel of the target clutch is obtained. When the difference between the speed value on the driven gear of the target clutch and the speed value of the driving wheel of the target clutch is less than the second threshold, the control proportional valve directly pressurizes the target clutch to the working pressure value, so that it is fully engaged, thereby realizing the synchronous rotation of the driving wheel and the driven gear of the clutch.

6. The control method for a transmission combining power shift and electro-hydraulic mechanical shift as described in claim 2, characterized in that, The clutch power gear downshift control method specifically includes the following steps: C1. Open the clutch switch valve of the target clutch, control the clutch proportional valve to give the target clutch a pre-engagement pressure value, and at the same time control the clutch proportional valve to reduce the pressure of the current clutch within a predetermined time, where the current clutch refers to the clutch corresponding to the current gear. C2. After the current clutch drops to the pre-engagement pressure value, quickly close the switching valve and proportional valve of the current clutch, and control the proportional valve of the target clutch to pressurize the target clutch at the fifth predetermined pressure rate. C3. Based on the detection value of the speed sensor n1, obtain the speed value of the driven gear of the target clutch; based on the engine speed value, obtain the speed value of the driving wheel of the target clutch; and control the engine speed to approach the speed of the driven gear of the target clutch. C4. When the difference between the speed value on the driven gear of the target clutch and the speed of the driving wheel of the target clutch is less than the third threshold, the control proportional valve directly pressurizes the target clutch to the working pressure value, so that it is fully engaged, thereby realizing the synchronous rotation of the driving wheel and the driven gear of the clutch. C5. Restore engine throttle speed after the target clutch is fully engaged.

7. The control method for a transmission combining power shifting and electro-hydraulic mechanical shifting as described in claim 5 or 6, characterized in that, When shifting gears under operating conditions, the pressure value for switching between the current clutch and the target clutch is 6.5-8 bar. When shifting gears under road conditions, the shifting pressure value is 1.5-2.5 bar. The load rate of the engine load data exceeds the preset ratio, and this state is stably maintained for a predetermined time without interruption. This is considered the operating condition. The current clutch refers to the clutch corresponding to the current gear.

8. The control method for a transmission combining power shift and electro-hydraulic mechanical shift as described in claim 2, characterized in that, The specific steps of the shifting and upshifting control method for synchronizer mechanical gears include: D1. Control the proportional valve of the current clutch to reduce the pressure of the current clutch to a first predetermined pressure value, where the current clutch refers to the clutch corresponding to the current gear. D2. Close the synchronizer switch valve corresponding to the current gear, and open the synchronizer switch valve corresponding to the target gear to shift gears; D3. After the mechanical gear synchronizer completes the shift, the proportional valve of the current clutch is pressurized to the second predetermined pressure value within a predetermined time, and then pressurized at the sixth predetermined pressure rate. When the speed sensor n1 is detected to have reached the predetermined value, the pressure is increased at a higher seventh predetermined pressure rate. D4. Based on the detection value of speed sensor n1, the speed value on the driven gear of the target clutch is obtained. Based on the engine speed value, the speed value of the driving wheel of the target clutch is obtained. When the difference between the speed value on the driven gear of the front clutch and the speed value of the driving wheel of the target clutch is less than the fourth threshold, the proportional valve is controlled to directly pressurize the current clutch to the working pressure value so that it is fully engaged, thereby realizing the synchronous rotation of the driving wheel and the driven gear of the clutch. The current clutch is the target clutch.

9. The control method for a transmission combining power shift and electro-hydraulic mechanical shift as described in claim 1, characterized in that, The specific steps of the shifting and downshifting control method for synchronizer mechanical gears include: E1. Control the proportional valve of the current clutch to reduce the pressure of the current clutch to the third predetermined pressure value, where the current clutch refers to the clutch corresponding to the current gear. E2. Close the synchronizer switch valve corresponding to the current gear, and open the synchronizer switch valve corresponding to the target gear to shift gears. E3. After the mechanical gear synchronizer completes the shift, the proportional valve of the current clutch is pressurized to the fourth predetermined pressure value within a predetermined time. The engine speed value is obtained. Based on the detection value of the speed sensor n1, the speed value on the driven gear of the target clutch is obtained, and the engine speed is controlled to increase to the same speed. E4. When the difference between the speed value on the driven gear of the target clutch and the engine speed value is less than the fifth threshold, the control proportional valve directly pressurizes the target clutch to the working pressure value, so that it is fully engaged, thereby realizing the synchronous rotation of the clutch driving wheel and the clutch driven gear. E5. Once the target clutch is fully engaged, control the engine speed to return to the throttle speed.

10. The control method for a transmission combining power shift and electro-hydraulic mechanical shift as described in claim 1, characterized in that, The power gears on the input shaft assembly include: power fourth gear (2), power third gear (3), power second gear (4), and power first gear (5). The clutches include: fourth gear clutch (23), third gear clutch (24), second gear clutch (25), and first gear clutch (26). The engine is connected to the left side of input shaft A. Power fourth gear (2), power third gear (3), power second gear (4), and power first gear (5) are loosely fitted on input shaft A. Power fourth gear (2) can pass through the fourth gear clutch (26). 3) Connected to and rotating synchronously with input shaft A, the third gear (3) can be connected to and rotate synchronously with input shaft A through the third gear clutch (24), the second gear (4) can be connected to and rotate synchronously with input shaft A through the second gear clutch (25), and the first gear (5) can be connected to and rotate synchronously with input shaft A through the first gear clutch (26). By engaging and disengaging the fourth gear clutch (23), the third gear clutch (24), the second gear clutch (25), and the first gear clutch (26), control of four gears can be achieved. The intermediate shaft component includes several gears mounted on the intermediate shaft B, including: a reverse gear (6), a first transmission gear (7), a second transmission gear (8), a third transmission gear (9), a fourth transmission gear (10), a fifth transmission gear (11), and a sixth transmission gear (12) mounted on the intermediate shaft B. The first transmission gear (7) meshes with the fourth power gear (2), the third transmission gear (9) meshes with the third power gear (3), the fifth transmission gear (11) meshes with the second power gear (4), and the sixth transmission gear (12) meshes with the first power gear (5). The idler shaft component specifically includes: an idler shaft F and an idler wheel (14) loosely fitted on the idler shaft F, the idler wheel (14) meshing with the reverse gear (6) for transmission; The synchronizer assembly mounted on the auxiliary transmission shaft C includes: a reverse gear (15), a mechanical first gear (16), a mechanical second gear (17), a first synchronizer (27), and a second synchronizer (28). The transmission gears include: an eighth transmission gear (18) and a seventh transmission gear (19). The reverse gear (15), mechanical first gear (16), and mechanical second gear (17) are all loosely fitted on the auxiliary transmission shaft C. The eighth transmission gear (18) and the seventh transmission gear (19) are both fixedly fitted on the auxiliary transmission shaft C. The first synchronizer (27) and the second synchronizer (28) are both mounted on the auxiliary transmission shaft C. The reverse gear (15) meshes with the idler gear (14) for transmission. Gear (16) meshes with the second transmission gear (8) for transmission, mechanical second gear (17) meshes with the fourth transmission gear (10) for transmission, reverse gear (15) can be connected to the auxiliary transmission shaft C through the first synchronizer (27) and rotate synchronously, mechanical first gear (16) and mechanical second gear (17) can be connected to the auxiliary transmission shaft C through the second synchronizer (28) and rotate synchronously; mechanical first gear (16) and mechanical second gear (17) can be connected to the auxiliary transmission shaft C through the second synchronizer (28) and rotate synchronously; by shifting gears left and right through the second synchronizer (28), two gears can be controlled; by shifting gears through the first synchronizer (27), reverse gear can be achieved; The output components specifically include: output shaft G, high-gear output gear (20), low-gear output gear (21), and third synchronizer (29); both the high-gear output gear (20) and the low-gear output gear (21) are loosely fitted on the output shaft G. The high-gear output gear (20) meshes with the eighth transmission gear (18) for transmission, and the low-gear output gear (21) meshes with the seventh transmission gear (19) for transmission; by shifting the gears left and right using the third synchronizer (29), two gear positions can be controlled.

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