Special vehicle AMT gearbox power takeoff device and control method

Abstract

The invention discloses a special vehicle AMT gearbox power takeoff device and a control method, the special vehicle AMT gearbox power takeoff device comprises a transmission assembly and a power takeoff assembly, the power takeoff assembly is installed on one side of a main box of the transmission assembly, and an auxiliary shaft high-gear gear in the transmission assembly is meshed with a power takeoff gear in the power takeoff assembly to achieve power transmission; a shifting fork shaft in the power takeoff assembly is in clearance fit with an air cylinder in the power takeoff assembly, the air cylinder is connected with a whole vehicle air source through an air pipe, the power takeoff device is characterized in that a spring is arranged on the shifting fork shaft in a sleeved mode, the spring is located between the shifting fork shaft in the power takeoff assembly and a limiting sleeve, and an electromagnetic valve is installed on the air pipe. The power takeoff control module is additionally arranged in an ECU control program of the AMT gearbox, automatic control over gear engaging and gear disengaging of the power takeoff in the parking and driving states is achieved, the requirements of various special vehicles for power takeoff control are met, misoperation is prevented, and the labor intensity of a driver is reduced.

Description

Technical Field

[0001] This invention belongs to the field of AMT transmission technology, and specifically relates to a power take-off device and control method for a special vehicle AMT transmission. Background Technology

[0002] In the field of special-purpose vehicles, the power take-off (PTO) is a key component that obtains power from the gearbox to achieve special functions. The traditional PTO's engagement and disengagement process is cumbersome. The driver needs to complete multiple steps in sequence, such as depressing the clutch, manually selecting the appropriate gear, and turning on the PTO switch. Each step requires precise operation, which not only increases the driver's workload but also easily leads to equipment failure due to operational errors, thus reducing work efficiency.

[0003] With the application and development of AMT / AT transmission technology, it has gradually matured and been applied and promoted in road transport, tractor vehicles and other models, and has been widely recognized. However, the power take-off unit on the existing AMT / AT transmission cannot effectively solve the problem of inappropriate gear shifting time caused by excessive input speed when shifting gears. This can easily lead to problems such as gear grinding and gear shifting failure, which not only affects the normal operation of the equipment, but also shortens the service life of the transmission and power take-off unit. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a power take-off device and control method for a special vehicle AMT transmission. By adding a power take-off control module to the AMT transmission ECU control program, the automatic control of power take-off engagement and disengagement in parking and driving states can be realized, meeting the power take-off control needs of various special vehicles, preventing misoperation, and reducing the labor intensity of drivers.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A power take-off (PTO) device for a special-purpose vehicle AMT transmission includes a transmission assembly and a PTO assembly. The PTO assembly is installed on one side of the main housing of the transmission assembly. The high-gear of the countershaft in the transmission assembly meshes with the PTO gear in the PTO assembly to transmit power. The shift fork shaft in the PTO assembly is clearance-fitted with a cylinder in the PTO assembly. The cylinder is connected to the vehicle's air source via an air pipe. A spring is sleeved on the shift fork shaft, located between the shift fork shaft and a limiting sleeve in the PTO assembly. A solenoid valve is installed on the air pipe and connected to the wiring harness in the transmission assembly. The transmission ECU controls the operation of the solenoid valve to control the air circuit opening and closing. A normally open signal switch is installed on the PTO assembly and connected to the vehicle's electrical wiring harness. The signal switch is installed at the end of the PTO shift fork shaft.

[0006] Preferably, the cylinder is made of die-cast aluminum.

[0007] A control method for a power take-off device in a special-purpose vehicle AMT transmission includes engaging and disengaging gears, wherein engaging gears includes the following steps: Step 1: When the PTO gear engagement button is pressed and a PTO gear engagement request is issued, the actual speed n of the gearbox input shaft is obtained and compared with the target speed n1. If the actual speed n of the input shaft is not greater than the target speed n1, the normal PTO gear engagement strategy is executed; if the actual speed n of the input shaft is greater than the target speed n1, the PTO driving gear engagement strategy is executed. Step 2: After entering the normal gear take-off (PTO) engagement strategy, the transmission ECU controls the clutch to open, triggering the PTO control air circuit solenoid valve to activate, the PTO engages gear and returns the PTO switch engagement signal, the clutch engages, and the vehicle achieves PTO gear engagement. Step 3: After entering the power take-off (PTO) driving gear shifting strategy, the current gear position of the transmission is obtained and compared with the target gear. If the current gear position of the transmission is the target gear, the PTO gear shifting operation is entered; if the transmission is currently in another non-target gear, the transmission ECU controls the transmission to switch to the target gear before the PTO gear shifting operation is entered. Step 4: The transmission ECU controls the transmission to maintain the target gear and the input shaft speed drops to the target speed n1. It then opens the clutch, triggers the PTO control air circuit solenoid valve to operate, the PTO engages the gear, and returns the PTO switch engagement signal. Step 5: The transmission ECU controls the clutch to engage, the transmission maintains the target gear, and the power take-off unit enables the vehicle to shift gears.

[0008] The removal of the gear includes the following steps: Step 1: When the PTO disengagement button is pressed and a PTO disengagement request is issued, the current gear position of the transmission is obtained and compared with the target gear. If the current gear position of the transmission is neutral, the normal PTO disengagement strategy is executed; if the current gear position of the transmission is the target gear, the PTO driving disengagement strategy is executed. Step 2: After entering the normal PTO disengagement strategy, the transmission ECU controls the clutch to open, triggering the PTO control air circuit solenoid valve to act, the PTO disengages and returns the PTO switch disengagement signal, the clutch engages, and the vehicle achieves PTO disengagement. Step 3: After entering the PTO driving disengagement strategy, the actual speed n of the transmission input shaft is compared with the target speed n2. If the actual speed n of the input shaft is not greater than the target speed n2, the PTO disengagement operation is initiated; if the actual speed n of the input shaft is greater than the target speed n2, the transmission ECU controls the transmission to maintain the target gear and the input shaft speed is reduced to the target speed n2, thus initiating the PTO disengagement operation. Step 4: The transmission ECU controls the transmission to maintain the target gear, disengages the clutch, and triggers the PTO control air circuit solenoid valve to operate; the PTO disengages and returns the PTO switch disengagement signal; Step 5: The transmission ECU controls the clutch to engage, the transmission maintains the target gear, and the power take-off achieves disengagement for driving.

[0009] Preferably, in the gear shifting step 1, the target speed n1 is the speed at which the power take-off can smoothly shift gears without any gear collision or grinding. This speed is determined through calibration tests.

[0010] Preferably, in the gear shifting step 3, the target gear is the gear that the vehicle needs to engage when the power take-off is working, and this gear is determined according to the vehicle's operating conditions.

[0011] Preferably, in step 1 of disengaging the gear, the target speed n2 is the speed at which the power take-off (PTO) can smoothly disengage without any disengagement jamming. This speed is determined through calibration tests.

[0012] Preferably, the transmission ECU has a power take-off (PTO) control module installed in its control program to achieve automatic control of the PTO operation, which satisfies the modular design of the control unit and allows the transmission ECU control module hardware and calibration software to be universal.

[0013] Preferably, in the gear shifting step 1, the target speed n1 can be adjusted according to different parameters of the matched power take-off, and can be applied to gear shifting control of power take-offs with different parameters. This speed value is determined through calibration tests.

[0014] Preferably, in the disengagement step 1, the target speed n2 can be adjusted according to the different loads at the output end of the power take-off, and can be applied to the disengagement control of the power take-off for different vehicle models. This speed value is determined through calibration tests.

[0015] The beneficial effects of this invention are: 1) Add a power take-off (PTO) control module to the AMT transmission ECU control program to realize automatic control of PTO engagement and disengagement in parking and driving states, meet the PTO control needs of various special vehicles, prevent misoperation, and reduce the labor intensity of drivers.

[0016] 2) By comparing rotational speeds, the timing of PTO gear engagement is precisely controlled to ensure smooth and unobstructed PTO gear engagement.

[0017] 3) By acquiring the PTO switch signal, determine whether the PTO is engaged or disengaged, and then open or close the clutch to effectively avoid the situation of incomplete engagement or disengagement, and ensure the success rate of PTO engagement and disengagement operations.

[0018] 4) Determine the optimal engagement and disengagement speeds based on the actual vehicle calibration to ensure that the PTO does not experience gear knocking or grinding during engagement and disengagement, while also improving the stability of the transmission system.

[0019] 5) The control module reads the gearbox input shaft speed and quickly controls the gearbox input shaft speed to reach the target speed, performing power take-off (PTO) gear engagement and disengagement operations to achieve rapid response and make PTO gear engagement and disengagement operations more timely and smooth. Attached Figure Description

[0020] Appendix Figure 1 This is a schematic diagram of the power take-off structure of a special vehicle AMT transmission according to the present invention.

[0021] Appendix Figure 2 This is a flowchart of the disengagement process of the power take-off unit of a special vehicle AMT transmission according to the present invention.

[0022] Appendix Figure 3 This is a flowchart of the gear shifting process of a special vehicle AMT transmission power take-off unit according to the present invention.

[0023] In the diagram: 1. Countershaft high gear; 2. Power take-off gear; 3. Spring; 4. Shift fork shaft; 5. Cylinder; 6. Solenoid valve; 7. Wiring harness; 8. Air pipe; 9. Air source; 10. Transmission ECU; 11. Signal switch. Detailed Implementation

[0024] The following is in conjunction with the appendix Figure 1-3 The technical solutions in the embodiments of the present invention are clearly and completely described herein. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0026] A power take-off (PTO) device for a special-purpose vehicle AMT transmission includes a transmission assembly and a PTO assembly. The PTO assembly is installed on one side of the main housing of the transmission assembly. The high-gear 1 of the countershaft in the transmission assembly meshes with the PTO gear 2 in the PTO assembly to transmit power. A shift fork shaft 4 in the PTO assembly is clearance-fitted with a cylinder 5 in the PTO assembly. The cylinder 5 is connected to a vehicle air source 9 via an air pipe 8. A spring 3 is sleeved on the shift fork shaft 4, located between the shift fork shaft 4 and a limiting sleeve in the PTO assembly. A spring 3 is mounted on the air pipe 8. Equipped with a solenoid valve 6, the air circuit is controlled to open or close. When the air circuit is open, the vehicle air source 9 provides pressurized gas to the cylinder 5, which drives the shift fork shaft 4 to move, and the power take-off (PTO) engages gears. When the air circuit is closed, the internal spring 3 of the PTO pushes the shift fork shaft 4 to reset, and the PTO disengages gears. The solenoid valve 6 is connected to the wiring harness 7 in the transmission assembly, and the operation of the solenoid valve 6 is controlled by the transmission ECU 10 to control the air circuit. The cylinder 5 is made of die-cast aluminum material to achieve the design goals of high machining accuracy and light weight.

[0027] A normally open signal switch 11 is installed on the power take-off assembly. The signal switch 11 is connected to the vehicle's electrical wiring harness and is installed at the end of the power take-off shift fork shaft 4. When the power take-off assembly is engaged, the signal switch 11 closes, the circuit is connected, and the power take-off engagement indicator light on the vehicle's instrument panel illuminates. When the power take-off assembly is disengaged, the signal switch 11 resets, the circuit is interrupted, and the power take-off engagement indicator light on the vehicle's instrument panel goes out. By controlling whether the signal switch 11 is engaged or disengaged, the illumination of the instrument panel indicator light is controlled, thereby realizing the reminder function for the driver.

[0028] When the driver presses the solenoid valve control switch to activate solenoid valve 6, the air circuit is connected, and compressed gas in air pipe 8 enters cylinder 5 to push shift fork shaft 4 to move axially, thus engaging the power take-off (PTO). At the same time, the end contact of compression signal switch 11 connects the signal switch 11 circuit, and the instrument panel displays that the PTO is engaged. When the driver presses the solenoid valve control switch again to reset solenoid valve 6, the air circuit is interrupted, and compressed gas in air pipe 8 is discharged through the exhaust port of solenoid valve 6. Spring 3 pushes shift fork shaft to move axially in the opposite direction, thus disengaging the PTO. The end contact of signal switch 11 resets, disconnecting the signal switch 11 circuit, and the instrument panel displays that the PTO is disengaged.

[0029] A power take-off device and control method for a special-purpose vehicle AMT transmission includes engaging and disengaging gears, wherein engaging gears includes the following steps: Step 1: When the PTO gear engagement button is pressed and a PTO gear engagement request is issued, the actual speed n of the gearbox input shaft is obtained and compared with the target speed n1. If the actual speed n of the input shaft is not greater than the target speed n1, the normal PTO gear engagement strategy is executed; if the actual speed n of the input shaft is greater than the target speed n1, the PTO driving gear engagement strategy is executed. Step 2: After entering the normal gear take-off (PTO) engagement strategy, the transmission ECU controls the clutch to open, triggering the PTO control air circuit solenoid valve to activate, the PTO engages gear and returns the PTO switch engagement signal, the clutch engages, and the vehicle achieves PTO gear engagement. Step 3: After entering the power take-off (PTO) driving gear shifting strategy, the current gear position of the transmission is obtained and compared with the target gear. If the current gear position of the transmission is the target gear, the PTO gear shifting operation is entered; if the transmission is currently in another non-target gear, the transmission ECU controls the transmission to switch to the target gear before the PTO gear shifting operation is entered. Step 4: The transmission ECU controls the transmission to maintain the target gear and the input shaft speed drops to the target speed n1, disengages the clutch, triggers the PTO control air circuit solenoid valve to operate; the PTO engages the gear and returns the PTO switch engagement signal; Step 5: The transmission ECU controls the clutch to engage, the transmission maintains the target gear, and the power take-off unit enables the vehicle to shift gears.

[0030] The removal of the gear includes the following steps: Step 1: When the PTO disengagement button is pressed and a PTO disengagement request is issued, the current gear position of the transmission is obtained and compared with the target gear. If the current gear position of the transmission is neutral, the normal PTO disengagement strategy is executed; if the current gear position of the transmission is the target gear, the PTO driving disengagement strategy is executed. Step 2: After entering the normal PTO disengagement strategy (usually the PTO is in a parking PTO condition), the transmission ECU controls the clutch to open, triggering the PTO control air circuit solenoid valve to act, the PTO is disengaged and returns the PTO switch disengagement signal, the clutch engages, and the vehicle achieves PTO disengagement. Step 3: After entering the PTO driving disengagement strategy, the actual speed n of the transmission input shaft is compared with the target speed n2. If the actual speed n of the input shaft is not greater than the target speed n2, the PTO disengagement operation is initiated; if the actual speed n of the input shaft is greater than the target speed n2, the transmission ECU controls the transmission to maintain the target gear and the input shaft speed is reduced to the target speed n2, thus initiating the PTO disengagement operation. Step 4: The transmission ECU controls the transmission to maintain the target gear, disengages the clutch, and triggers the PTO control air circuit solenoid valve to operate; the PTO disengages and returns the PTO switch disengagement signal; Step 5: The transmission ECU controls the clutch to engage, the transmission maintains the target gear, and the power take-off achieves disengagement for driving.

[0031] In the gear shifting step 1, the target speed n1 is the speed at which the power take-off can smoothly shift gears without gear collision or grinding. This speed is determined through calibration tests.

[0032] In step 3 of shifting gears, the target gear is the gear that the vehicle needs to be engaged when the power take-off is working (e.g., when a water truck is carrying out road watering operations, it generally uses 2nd or 3rd gear). This gear is determined based on the vehicle's operating conditions.

[0033] In step 1 of the gear disengagement process, the target speed n2 is the speed at which the power take-off (PTO) can smoothly disengage without any jamming. This speed is determined through calibration tests (the target speed n1 during PTO engagement control and the target speed n2 during PTO disengagement control are not necessarily the same).

[0034] The transmission ECU control program is enhanced with a power take-off (PTO) control module to enable automatic control of the PTO operation. This satisfies the modular design of the control unit, allowing for universal hardware and calibration software for the transmission ECU control module. The control module reads the transmission input shaft speed and quickly controls it to reach the target speed, enabling PTO engagement and disengagement operations with rapid response and smoother, more timely PTO engagement and disengagement.

[0035] In the gear shifting step 1, the target speed n1 can be adjusted according to the different parameters of the matched power take-off, and can be applied to the gear shifting control of power take-offs with different parameters. This speed value is determined through calibration tests.

[0036] In step 1 of the gear shifting process, the target speed n2 can be adjusted according to the different loads at the output end of the power take-off unit, and can be applied to the gear shifting control of power take-off units of different vehicle models. This speed value is determined through calibration tests.

[0037] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A power take-off (PTO) device for a special-purpose vehicle AMT transmission, comprising a transmission assembly and a PTO assembly, wherein the PTO assembly is mounted on one side of the main housing of the transmission assembly, the high-gear countershaft in the transmission assembly meshes with the PTO gear in the PTO assembly to transmit power, the shift fork shaft in the PTO assembly is clearance-fitted with a cylinder in the PTO assembly, and the cylinder is connected to the vehicle's air supply via an air pipe, characterized in that... A spring is sleeved on the shift fork shaft, and the spring is located between the shift fork shaft and the limiting sleeve in the power take-off assembly. A solenoid valve is installed on the air pipe, and the solenoid valve is connected to the wiring harness in the transmission assembly. A normally open signal switch is installed on the power take-off assembly, and the signal switch is connected to the vehicle electrical wiring harness. The signal switch is installed at the end of the power take-off shift fork shaft.

2. The power take-off device for a special-purpose vehicle AMT transmission according to claim 1, characterized in that, The cylinder is made of die-cast aluminum.

3. The control method for a power take-off device of a special vehicle AMT transmission according to claim 1, characterized in that, This includes engaging and disengaging gears, wherein engaging gears includes the following steps: Step 1: When the PTO gear engagement button is pressed and a PTO gear engagement request is issued, the actual speed n of the gearbox input shaft is obtained and compared with the target speed n1. If the actual speed n of the input shaft is not greater than the target speed n1, the normal PTO gear engagement strategy is executed; if the actual speed n of the input shaft is greater than the target speed n1, the PTO driving gear engagement strategy is executed. Step 2: After entering the normal gear take-off (PTO) engagement strategy, the transmission ECU controls the clutch to open, triggering the PTO control air circuit solenoid valve to activate, the PTO engages gear and returns the PTO switch engagement signal, the clutch engages, and the vehicle achieves PTO gear engagement. Step 3: After entering the power take-off (PTO) driving gear shifting strategy, the current gear position information of the transmission is obtained and compared with the target gear. If the current gear position of the transmission is the target gear, the PTO gear shifting operation is entered. If the transmission is currently in another non-target gear, the transmission ECU controls the transmission to switch to the target gear and then enters the PTO gear shifting operation. Step 4: The transmission ECU controls the transmission to maintain the target gear and the input shaft speed drops to the target speed n1. It then opens the clutch, triggers the PTO control air circuit solenoid valve to operate, the PTO engages the gear, and returns the PTO switch engagement signal. Step 5: The transmission ECU controls the clutch to engage, the transmission maintains the target gear, and the power take-off unit enables the vehicle to shift gears.

4. The control method for a power take-off device of a special vehicle AMT transmission according to claim 3, characterized in that, The removal of the gear includes the following steps: Step 1: When the PTO disengagement button is pressed and a PTO disengagement request is issued, the current gear position of the transmission is obtained and compared with the target gear. If the current gear position of the transmission is neutral, the normal PTO disengagement strategy is executed; if the current gear position of the transmission is the target gear, the PTO driving disengagement strategy is executed. Step 2: After entering the normal PTO disengagement strategy, the transmission ECU controls the clutch to open, triggering the PTO control air circuit solenoid valve to act, the PTO disengages and returns the PTO switch disengagement signal, the clutch engages, and the vehicle achieves PTO disengagement. Step 3: After entering the PTO driving disengagement strategy, the actual speed n of the transmission input shaft is compared with the target speed n2. If the actual speed n of the input shaft is not greater than the target speed n2, the PTO disengagement operation is initiated; if the actual speed n of the input shaft is greater than the target speed n2, the transmission ECU controls the transmission to maintain the target gear and the input shaft speed is reduced to the target speed n2, thus initiating the PTO disengagement operation. Step 4: The transmission ECU controls the transmission to maintain the target gear, disengages the clutch, and triggers the PTO control air circuit solenoid valve to operate; the PTO disengages and returns the PTO switch disengagement signal; Step 5: The transmission ECU controls the clutch to engage, the transmission maintains the target gear, and the power take-off achieves disengagement for driving.

5. The control method for a power take-off device of a special vehicle AMT transmission according to claim 3, characterized in that, In the gear shifting step 1, the target speed n1 is the speed at which the power take-off can smoothly shift gears without gear collision or grinding. This speed is determined through calibration tests.

6. The control method for a power take-off device of a special vehicle AMT transmission according to claim 3, characterized in that, In the gear shifting step 3, the target gear is the gear that the vehicle needs to engage when the power take-off is working, and this gear is determined according to the vehicle's operating conditions.

7. The control method for a power take-off device of a special vehicle AMT transmission according to claim 4, characterized in that, In step 1 of the disengagement process, the target speed n2 is the speed at which the power take-off (PTO) can smoothly disengage without any jamming during disengagement. This speed is determined through calibration tests.

8. A control method for a power take-off device of a special-purpose vehicle AMT transmission according to claim 3 or 4, characterized in that, The transmission ECU has a power take-off (PTO) control module installed in its control program, which enables automatic control of the PTO operation. This satisfies the modular design of the control unit, and the hardware and calibration software of the transmission ECU control module can be universally used.

9. The control method for a power take-off device of a special vehicle AMT transmission according to claim 3, characterized in that, In the gear shifting step 1, the target speed n1 can be adjusted according to the different parameters of the matched power take-off, and is applicable to the gear shifting control of power take-offs with different parameters. This speed value is determined through calibration tests.

10. The control method for a power take-off device of a special-purpose vehicle AMT transmission according to claim 4, characterized in that, In the disengagement step 1, the target speed n2 can be adjusted according to the different loads at the output end of the power take-off, which is applicable to the disengagement control of the power take-off for different vehicle models. This speed value is determined through calibration tests.

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