Control method for improving gear shifting success rate of tractor gearbox

Abstract

The invention discloses a control method for improving the gear shifting success rate of a tractor gearbox. The control method mainly solves the technical problems that an existing gear shifting method is too long in gear shifting time, prone to gear shifting failure and the like. According to the invention, gear switching in a starting process, switching of adjacent gears after starting, gear switching in a parking state or a forward driving state, gear switching in a reverse driving state, switching of a climbing gear and a direct gear, and gear switching when the climbing gear is in a gear state are respectively controlled; corresponding speed regulation strategies are adopted according to different driving states and dragging force conditions of the tractor, the gear shifting success rate is effectively increased, and the working efficiency and reliability of the tractor are effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a gearbox shift control method, in particular to a control method for improving the success rate of tractor gearbox shifting. BACKGROUND

[0002] In the transmission system of agricultural machinery such as tractors, the performance of the gearbox has an important influence on the working efficiency and reliability of the whole machine. At present, the power shift gearbox of the tractor is usually designed with multiple gears, and different transmission ratios are achieved through the cooperation of the main gearbox and the auxiliary gearbox, so as to adapt to various complex working conditions.

[0003] For example, the invention patent with publication number CN120701747A discloses a tractor electric control synchronizer speed synchronization control method, system, device and medium. The main speed clutch and the auxiliary speed synchronizer are operated by a clear preset strategy to ensure the orderly execution of the shifting action. At the same time, the target synchronizer speed difference is calculated based on the target gear position and the current gear position, and whether the preset condition is met is judged based on this, and the corresponding control strategy is adopted. However, due to the drag force generated by the oil in the gearbox, the rotational speed of each gear shaft in the actual control process is uncertain, which leads to too long shifting time during shifting operation, and even shifting failure, thereby reducing the working efficiency and reliability of the tractor. SUMMARY

[0004] The purpose of the present application is to provide a control method for improving the success rate of tractor gearbox shifting, which solves the technical problems of the existing shifting method, such as long shifting time and easy shifting failure.

[0005] To achieve the above purpose, the technical solution provided by the present application is as follows:

[0006] A control method for improving the success rate of tractor gearbox shifting, the tractor gearbox comprising a main gearbox and an auxiliary gearbox; the main gearbox has 9 gears, and the auxiliary gearbox has 5 gears; a direct gear and a climbing gear are arranged between the main gearbox and the auxiliary gearbox; the special feature is that the following control logic is included:

[0007] Control logic 1: gear switching control during starting process

[0008] When the current engine speed is less than the idle speed, the direct gear is engaged first, and then the auxiliary gearbox 2 is engaged; when the current engine speed is within the speed regulation range, control logic 2 is executed; the speed regulation range refers to the idle speed of the engine to the maximum speed of the engine;

[0009] Control logic 2: switching control of adjacent gears after starting

[0010] The auxiliary gearbox can only be shifted when the current vehicle speed is less than the preset vehicle speed threshold V1 and the steering lever is in the neutral position and the main gearbox is in neutral.

[0011] If the current vehicle speed is greater than or equal to the preset vehicle speed threshold V1 and the main gearbox is not in neutral, if the current engine speed is within its speed adjustment range and can match the gearbox's desired gear, then the main gearbox will start to return to neutral, and then the auxiliary gearbox will shift gears; otherwise, the auxiliary gearbox will not shift gears.

[0012] Control Logic 3: Gear Shift Control in Parked or Moving Mode

[0013] If the current speed of the hollow shaft is within the preset speed threshold |N1|, the speed adjustment process is skipped. When the desired gear and the actual gear are the same, the gear shift is complete. If the current speed of the hollow shaft exceeds the preset speed threshold |N1|, the speed adjustment process is entered and the corresponding gear is switched.

[0014] Control Logic 4: Gear Shifting Control in Reverse Driving Mode

[0015] When the vehicle is in reverse, the driver puts the master gear into neutral. If the desired gear and the actual gear are the same, the gear shift is complete. If the gear shift fails during this process, the corresponding gear switch is executed according to control logic 3.

[0016] Control Logic 5: Switching between creeper and direct drive gears

[0017] When the current engine speed is greater than its idle speed, the vehicle speed is less than the preset vehicle speed threshold V1, and the steering lever is in the neutral position, the foot brake pedal is pressed, the gear shift request is responded to, and the gear shift between creep and direct drive is executed according to control logic 3; otherwise, the gear shift request is not responded to.

[0018] Control Logic 6: Gear Shifting Control When Climbing Gears

[0019] When the gear is in the climbing gear, the threshold speed of the hollow shaft is limited to the preset speed range, and the corresponding gear is switched according to control logic 3.

[0020] Furthermore, in control logic 1, when the current engine speed is less than its idle speed, the current engine speed is 500~600 rpm and the idle speed is 750~800 rpm.

[0021] Furthermore, in control logic 2, the preset vehicle speed threshold V1 is 0.2~1km / h;

[0022] The current engine speed is calculated based on the current vehicle speed.

[0023] Furthermore, in control logic 3, the current rotational speed of the hollow shaft is detected by a speed sensor installed on the hollow shaft of the main housing;

[0024] The preset speed threshold |N1| is set to 50~100 rpm.

[0025] Furthermore, in control logic 3, the specific process of switching the corresponding gear in the speed regulation loop is as follows:

[0026] The tractor's transmission control system requests a pressure P to the reverse clutch of the main gearbox to put it in a slipping state, and the request time is T0. After time T0, the pressure becomes 0. During this period, the reverse clutch will drive the hollow shaft to change from forward rotation to reverse rotation. When the speed of the hollow shaft is less than |N1|, the auxiliary gearbox starts to shift gears. If the desired gear and the actual gear are the same, it means that the shift is complete.

[0027] If the desired gear is not equal to the actual gear after time T1 (T1 > T0), the auxiliary gearbox stops shifting, and the tractor gearbox control system requests a pressure P to the reverse clutch of the main gearbox again, and repeats the above operation. If the desired gear and the actual gear are the same after multiple repetitions, it means that the shifting is complete; if the desired gear and the actual gear are still different after multiple repetitions, it requests that the desired gear be replaced by the actual gear of the previous state, and stops shifting.

[0028] Furthermore, in control logic 3, the pressure P is set to 4~5 bar, corresponding to a temperature of 20~60℃.

[0029] Furthermore, in control logic 3, the number of repetitions is 3 to 5 times.

[0030] Furthermore, in control logic 6, the preset speed range is between (-N1+N2) and (+N1-N2), where N2 is 20~30 rpm.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] 1. The control method for improving the shifting success rate of tractor gearboxes provided by the present invention controls the shifting of gears during the starting process, the shifting of adjacent gears after starting, the shifting of gears in the parking state or forward driving state, the shifting of gears in the reverse driving state, the shifting of upshift and direct drive, and the shifting of gears when upshift is in gear. It adopts corresponding speed adjustment strategies for different driving states and towing force conditions of the tractor, effectively improving the shifting success rate, as well as the working efficiency and reliability of the tractor.

[0033] 2. This invention indirectly determines the oil drag force by utilizing the rotational speed of the hollow shaft, and optimizes the shift control logic of the auxiliary gearbox, creep gear, and direct drive by adjusting the speed through the reverse clutch, thereby further improving the shift success rate. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the tractor gearbox in an embodiment of the present invention.

[0035] The attached figures are labeled as follows:

[0036] 1-Speed ​​sensor, 2-Direct drive, 3-Climbing gear, 4-Auxiliary gearbox 4th gear, 5-Auxiliary gearbox 3rd gear, 6-Auxiliary gearbox 5th gear, 7-Auxiliary gearbox 2nd gear, 8-Auxiliary gearbox 1st gear. Detailed Implementation

[0037] To make the objectives, advantages, and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0038] This embodiment provides a control method for improving the shifting success rate of tractor gearboxes. It is mainly used to solve the problem that the oil drag force affects the shifting effect during the shifting process of existing tractor gearboxes, thereby improving the shifting success rate.

[0039] like Figure 1 As shown, taking a certain model of tractor as an example, the tractor's gearbox includes a main gearbox and an auxiliary gearbox. The main gearbox has 9 gears, divided into 6 forward gears and 3 reverse gears. Each of the 9 gears is composed of 6 wet clutches combined in pairs. The 6 wet clutches are named CF1, CF2, CL, CM, CH, and CR. The auxiliary gearbox has 5 gears: auxiliary gearbox 1 (gear 8), auxiliary gearbox 2 (gear 7), auxiliary gearbox 3 (gear 5), auxiliary gearbox 4 (gear 4), and auxiliary gearbox 5 (gear 6), all shifted using synchronizers. Additionally, a creeper gear 3 and a direct drive gear 2 are located between the main and auxiliary gearboxes, also shifted using synchronizers. The speed ratio of direct drive gear 2 is 1, and the speed ratio of creeper gear 3 is i (i > 1). Furthermore, a hollow shaft speed sensor 1 is installed in the main gearbox to detect the speed of the hollow shaft in real time, thereby determining the magnitude of the hydraulic drag force.

[0040] This embodiment of a control method for improving the shifting success rate of a tractor gearbox includes the following control logic:

[0041] Control Logic 1: Gear Shift Control During Startup

[0042] When the current engine speed is lower than its idle speed, the system hydraulic pressure gradually builds up. At this time, the default is to first engage direct drive 2 and then engage auxiliary gear 2 7. When the current engine speed is within its speed regulation range, control logic 2 is executed. The speed regulation range mentioned here refers to the engine's idle speed to its maximum speed.

[0043] In this embodiment, when the current engine speed is less than its idle speed, the current engine speed is 500~600 rpm, and the idle speed is generally 750~800 rpm.

[0044] Control Logic 2: Switching control between adjacent gears after startup

[0045] The auxiliary gearbox can only be shifted if the current vehicle speed is less than the preset vehicle speed threshold V1 (0.2~1km / h) and the steering lever is in the neutral position and the main gearbox is in neutral.

[0046] If the current vehicle speed is greater than or equal to the preset vehicle speed threshold V1 and the main gearbox is not in neutral, if the current engine speed (calculated from the current vehicle speed) is within its speed regulation range and can match the gear desired by the main gearbox, then the main gearbox will start to return to neutral, and then the auxiliary gearbox will shift gears; otherwise, the shift request will not be responded to and the auxiliary gearbox will not shift gears.

[0047] Control Logic 3: Gear Shift Control in Parked or Moving Mode

[0048] The control principle is as follows: when the main gearbox is in neutral, i.e., the power is interrupted, if the output shaft of the main gearbox has a rotational speed, the speed is adjusted according to the rotational speed of the hollow shaft.

[0049] If the current speed of the hollow shaft is within the preset speed threshold |N1| (i.e., between -N1 and +N1), such as 50 rpm, it indicates that the current oil drag force is relatively small. In this case, a drag-no-speed-adjustment flag is issued directly, skipping the speed adjustment process. The shift is complete when the desired gear and the actual gear are the same. The preset speed threshold |N1| is set to 50~100 rpm, and in this embodiment, it is set to 50 rpm.

[0050] If the current speed of the hollow shaft exceeds the preset speed threshold |N1|, such as 120 rpm, it indicates that the oil drag force is large. In this case, an activation drag speed regulation flag is issued, entering the speed regulation phase and switching to the corresponding gear. The gear switching process is as follows:

[0051] The tractor's transmission control system requests a small pressure P (e.g., 4 bar) to be applied to the reverse (CR) clutch of the main gearbox, causing the reverse clutch to slip. The request time is T0 (e.g., 1 second). After time T0, the pressure becomes 0. During this period, the reverse clutch will drive the hollow shaft to change from forward rotation to reverse rotation. When the speed of the hollow shaft is less than |N1|, the auxiliary gearbox begins to shift gears. If the desired gear and the actual gear are the same, it means that the shift is complete.

[0052] If the desired gear is not equal to the actual gear after time T1 (e.g., 3s), the auxiliary gearbox stops shifting, and the tractor gearbox control system requests a small pressure P to be applied to the reverse clutch of the main gearbox again, and repeats the above operation. If the desired gear and the actual gear are the same after repeating multiple times (e.g., 3 times), it means that the shifting is complete; if the desired gear and the actual gear are still different after repeating multiple times, it requests that the desired gear be replaced by the actual gear of the previous state, and stops shifting.

[0053] Control Logic 4: Gear Shifting Control in Reverse Driving Mode

[0054] When the vehicle is in reverse, after the driver activates the shift command by pressing the auxiliary gearbox shift button, there is no need to match the main gearbox gear. The main gearbox is directly returned to neutral. At this time, the direction of the hollow shaft rotation changes from reverse to forward. When the hollow shaft speed is within the threshold |N1|, a drag-without-speed-adjustment flag is issued directly, skipping the speed adjustment step and shifting gears. If the desired gear and the actual gear are the same, it means that the shift is complete. During this process, if the first shift fails, the vehicle slowly coasts to a stop. Subsequent shifts determine whether speed adjustment is needed and the control logic is the same as control logic 3. The corresponding gear switching is executed according to control logic 3.

[0055] Control Logic 5: Switching control between Climbing Gear 3 and Direct Drive Gear 2

[0056] The shift between gear 3 and direct drive 2 is only allowed when the following conditions are met simultaneously: when the current engine speed is greater than its idle speed, the vehicle speed is less than the preset vehicle speed threshold V1, and the steering lever is in the neutral position, the foot brake pedal is pressed, and then the shift button is pressed to respond to the shift request and execute the shift between gear 3 and direct drive 2 according to control logic 3; otherwise, the shift request is not responded to.

[0057] It should be noted that when the auxiliary gearbox is in gear, it affects the shifting operation of the crawl gear 3 and direct gear 2; when the crawl gear 3 or direct gear 2 is in gear, it affects the shifting operation of the auxiliary gearbox.

[0058] Control Logic 6: Gear Shifting Control When Climbing Gear 3 is in Gear

[0059] When the crawler gear 3 is in gear, press the auxiliary gear shift button. If the drag force is large, the speed ratio of crawler gear 3 (i=9) will make the input speed of the auxiliary gear decrease but the moment of inertia increase, making it more difficult to shift gears in the auxiliary gear. At this time, the threshold of the hollow shaft speed is limited to the preset speed range, so that the judgment range is reduced. Then, the corresponding gear shift is executed according to control logic 3.

[0060] In this embodiment, the preset speed range is between (-N1+N2) and (+N1-N2), where N2 is 20~30 rpm.

[0061] The above control method can effectively solve the shifting problem caused by hydraulic drag in practical applications and significantly improve the shifting performance of tractor gearboxes.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A control method for improving the shifting success rate of a tractor gearbox, the tractor gearbox comprising a main gearbox and an auxiliary gearbox; the main gearbox having 9 gears and the auxiliary gearbox having 5 gears, with a creeper gear and a direct drive gear provided between the main gearbox and the auxiliary gearbox; characterized in that, Includes the following control logic: Control Logic 1: Gear Shift Control During Startup When the current engine speed is lower than its idle speed, the default is to first engage direct drive and then engage auxiliary gear 2; when the current engine speed is within its speed regulation range, control logic 2 is executed; the speed regulation range refers to the engine's idle speed to its maximum speed. Control Logic 2: Switching control between adjacent gears after startup The auxiliary gearbox can only be shifted when the current vehicle speed is less than the preset vehicle speed threshold V1 and the steering lever is in the neutral position and the main gearbox is in neutral. If the current vehicle speed is greater than or equal to the preset vehicle speed threshold V1 and the main gearbox is not in neutral, if the current engine speed is within its speed adjustment range and can match the gearbox's desired gear, then the main gearbox will start to return to neutral, and then the auxiliary gearbox will shift gears; otherwise, the auxiliary gearbox will not shift gears. Control Logic 3: Gear Shift Control in Parked or Moving Mode If the current speed of the hollow shaft is within the preset speed threshold |N1|, the speed adjustment process is skipped. When the desired gear and the actual gear are the same, the gear shift is complete. If the current speed of the hollow shaft exceeds the preset speed threshold |N1|, the speed adjustment process is entered and the corresponding gear is switched. Control Logic 4: Gear Shifting Control in Reverse Driving Mode When the vehicle is in reverse, the driver puts the master gear into neutral. If the desired gear and the actual gear are the same, the gear shift is complete. If the gear shift fails during this process, the corresponding gear switch is executed according to control logic 3. Control Logic 5: Switching between creeper and direct drive gears When the current engine speed is greater than its idle speed, the vehicle speed is less than the preset vehicle speed threshold V1, and the steering lever is in the neutral position, the foot brake pedal is pressed, the gear shift request is responded to, and the gear shift between creep and direct drive is executed according to control logic 3; otherwise, the gear shift request is not responded to. Control Logic 6: Gear Shifting Control When Climbing Gears When the gear is in the climbing gear, the threshold speed of the hollow shaft is limited to the preset speed range, and the corresponding gear is switched according to control logic 3.

2. The control method for improving the shifting success rate of a tractor gearbox according to claim 1, characterized in that: In control logic 1, when the current engine speed is less than its idle speed, the current engine speed is 500~600 rpm and the idle speed is 750~800 rpm.

3. The control method for improving the shifting success rate of a tractor gearbox according to claim 1, characterized in that: In control logic 2, the preset vehicle speed threshold V1 is 0.2~1km / h; The current engine speed is calculated based on the current vehicle speed.

4. The control method for improving the shifting success rate of a tractor gearbox according to claim 1, characterized in that: In control logic 3, the current rotational speed of the hollow shaft is detected by a speed sensor installed on the hollow shaft of the main housing; The preset speed threshold |N1| is set to 50~100 rpm.

5. The control method for improving the shifting success rate of a tractor gearbox according to claim 4, characterized in that: In control logic 3, the specific gear switching process in the speed regulation loop is as follows: The tractor's transmission control system requests a pressure P to the reverse clutch of the main gearbox to put it in a slipping state, and the request time is T0. After time T0, the pressure becomes 0. During this period, the reverse clutch will drive the hollow shaft to change from forward rotation to reverse rotation. When the speed of the hollow shaft is less than |N1|, the auxiliary gearbox starts to shift gears. If the desired gear and the actual gear are the same, it means that the shift is complete. If the desired gear is not equal to the actual gear after time T1 (T1 > T0), the auxiliary gearbox stops shifting, and the tractor gearbox control system requests a pressure P to the reverse clutch of the main gearbox again, and repeats the above operation. If the desired gear and the actual gear are the same after multiple repetitions, it means that the shifting is complete; if the desired gear and the actual gear are still different after multiple repetitions, it requests that the desired gear be replaced by the actual gear of the previous state, and stops shifting.

6. The control method for improving the shifting success rate of a tractor gearbox according to claim 5, characterized in that: In control logic 3, the pressure P is 4~5 bar, and the corresponding temperature is 20~60℃.

7. The control method for improving the shifting success rate of a tractor gearbox according to claim 6, characterized in that: In control logic 3, the number of repetitions is 3 to 5 times.

8. The control method for improving the shifting success rate of a tractor gearbox according to claim 1, characterized in that: In control logic 6, the preset speed range is between (-N1+N2) and (+N1-N2), where N2 is 20~30 rpm.

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