JP2003314593A - Clutch control device for automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a clutch control device for an automatic transmission having no difference of creep force due to a secular distortion and variation, and offering an excellent creep feeling. <P>SOLUTION: The device is provided with a control means for switching the speed change state of the synchromesh automatic transmission on the basis of detection signals of an engine speed sensor, a brake switch, a range switch, an acceleration position sensor and a vehicle speed sensor. In the control means, creep travel of a vehicle is executed when the shift position is in the traveling range and no detection by the brake switch and acceleration position is made, whereby the characteristics of the relationship between the clutch transmission torque and the clutch exciting current is corrected so as to make the value of the clutch transmission torque when the actual vehicle speed by the vehicle speed sensor reaches the target speed, conform to that when the actual vehicle speed at the time of the previous creep travel reaches the target speed. <P>COPYRIGHT: (C)2004,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clutch control device for an automatic transmission, and more particularly to a technology for absorbing aging and variations in clutch transmission torque and improving running feeling. Things. 2. Description of the Related Art Conventionally, as a clutch control method for a vehicle engine, for example, there is a method disclosed in Japanese Patent Application Laid-Open No. 6-206481. The apparatus described in the above publication employs a method of controlling the wet type single-plate clutch by hydraulic pressure, and includes a hydraulic pressure sensor. When starting, the clutch control hydraulic pressure is closed-loop controlled by the input of the pressure sensor. The target clutch pressure at the time of starting is corrected based on the difference between the engine torque predicted from the oil pressure sensor input value at the time of starting and the engine torque calculated from the engine torque map. [0003] In the conventional clutch control device for an automatic transmission, since only the target clutch pressure at the time of starting is corrected as described above, for example, the clutch pressure at the time of creep running is corrected. Will not be. For this reason, if the creep force is too weak or too strong due to aging or variation, there is a problem that a good running feeling cannot be obtained. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a clutch control device for an automatic transmission which can obtain a good creep feeling without a difference in creep force due to aging and variations. It is intended to be realized. A clutch control device for an automatic transmission according to the present invention provides a clutch transmission torque calculated based on a deviation signal obtained by a closed loop control based on a deviation between a target vehicle speed and an actual vehicle speed. A clutch control device of an automatic transmission that converts a clutch transmission torque to a clutch excitation current based on a relation characteristic of a clutch excitation current and supplies the clutch excitation current to an electromagnetic powder clutch to cause the vehicle to creep. An engine rotation sensor that detects an engine rotation speed, a brake switch that detects a state in which a brake pedal is depressed, a range switch that detects a shift position of a travel range, a neutral range, and a reverse range, and an accelerator pedal An accelerator that detects the amount of depression as the accelerator opening Position sensor, a vehicle speed sensor that detects an output rotation speed of the synchronous meshing transmission as a vehicle speed, and a detection signal from the engine rotation sensor, the brake switch, the range switch, the accelerator position sensor, and the vehicle speed sensor. Control means for switching the gearshift state of the synchronous meshing transmission, wherein the control means creeps the vehicle when the shift position is in the travel range and there is no detection by the brake switch and the accelerator position. The vehicle is driven so that the value of the clutch transmission torque when the actual vehicle speed by the vehicle speed sensor reaches the target speed becomes the value of the clutch transmission torque when the actual vehicle speed during the previous creep traveling reaches the target speed. For correcting the relationship characteristic of the clutch transmission torque-clutch excitation current. A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment Hereinafter, Embodiment 1 of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram schematically showing a first embodiment of the present invention. In FIG. 1, a crankshaft 2 of an engine 1 is shown.
1 is connected via an electromagnetic powder clutch 2 to a synchronous meshing stepped transmission 3 (hereinafter simply referred to as a "stepped transmission 3") constituting a synchronous meshing automatic transmission. The control unit 4 includes a microcomputer having various arithmetic functions, and controls the engine 1 based on various sensor information indicating the operating state of the engine 1.
The electromagnetic powder clutch 2 and the stepped transmission 3 are controlled. [0009] The shift / select actuator 5 drives the stepped transmission 3 under the control of the control unit 4. The shift / select position sensor 6 detects the actual shift / select positions VY and VX of the stepped transmission 3 and inputs the detected positions to the control unit 4. A fourth speed gear 23 functioning as a primary gear is directly connected to the input shaft 22 of the stepped transmission 3. Behind the fourth gear 23, the third gear 24,
A second speed gear 25, a first speed gear 26, a fifth speed gear 27, and a reverse gear 28 are sequentially arranged. Between the gears 23 to 28, three sleeve gears 29 are arranged. Each sleeve gear 29
It is directly connected to the output shaft 30 of the stepped transmission 3 and is movable in the axial direction. Each of the gears 23 to 28 forms a set with a gear directly connected to a counter shaft 31 provided side by side with the output shaft 30, and is always meshed with a gear on the counter shaft 31. With the above configuration, the output shaft 3
0 is directly connected to the input shaft 22 by being directly connected to any of the gears 23 to 28 via the sleeve gear 29. In this case, the stepped transmission 3 is a countershaft type five-speed gear transmission, which includes five forward gear sets having different gear ratios, one reverse gear set, and a gear meshing state switching. And three sleeve gears. The fourth gear 23 on the input shaft 22
Is provided with an input rotation speed sensor 7 for detecting an input rotation speed Ni of the stepped transmission 3. The output shaft 30 is provided with an output rotation speed sensor 8 for detecting the output rotation speed of the stepped transmission 3 as the vehicle speed Vr. A throttle valve 1 driven by a throttle actuator 11 is provided in an intake pipe 9 of the engine 1.
0 is provided. Throttle position sensor 12
Detects the opening degree θ of the throttle valve 10. The accelerator position sensor 13 outputs a signal proportional to the amount of depression of an accelerator pedal (not shown) by the driver as an accelerator opening α.
To enter. The control unit 4 processes the output signal of the accelerator position sensor 13, calculates a target throttle opening θo corresponding to the accelerator opening α, and controls the throttle opening θ in a feedback (F / B) manner. , Θ
The throttle valve 10 is driven via the throttle actuator 11 so that = θo. The shift lever 14 is operated by a driver in a shift position (eg, a parking range P, a reverse range R, a neutral range N, and a driving range D).
Is input to the control unit 4. The engine speed sensor 15 detects the speed Ne of the engine 1 and inputs it to the control unit 4. The reverse gear 28 in the stepped transmission 3 is provided with a reverse gear switch 16 for detecting the operating state of the reverse gear. The brake switch 17 inputs to the control unit 4 a signal indicating a brake operation state while the driver is depressing a brake pedal (not shown). The control unit 4 determines a shift based on various sensor signals, and controls the shift / select actuator 5 in accordance with the shift determination, and determines a shift pattern (shift diagram) based on the accelerator opening α and the vehicle speed Vr. The gear speed is set to the required shift speed, and the plurality of gear speeds of the stepped transmission 3 are automatically switched. Next, a basic operation according to the first embodiment of the present invention shown in FIG. 1 will be described. The electromagnetic clutch 2 is driven by a clutch exciting current proportional to the clutch transmission torque under the control of the control unit 4,
The power transmission (or interruption) from the crankshaft 21 of the engine 1 to the input shaft 22 of the stepped transmission 3 is controlled. In the step-variable transmission 3, the input rotation is performed first by the forefront primary gear (input shaft 2).
2) is transmitted to the counter shaft 31. The output shaft 30 is extended to the front of the third-speed gear set, and the transmission path and speed ratio (gear ratio of the primary gear × gear ratio of each speed gear) change depending on which of the above gears is connected. I do. In the fourth speed, the input shaft 22
And the output shaft 30 is directly connected. In the stepped transmission 3, a shift operation is performed by controlling the shift of the sleeve gear 29 by the shift / select actuator 5 for gear switching. That is, the step-variable transmission 3 releases the mechanical engagement of the gears of the current gear and the gear of the next gear by the shift control of the sleeve gear 29. It is switched to the connection operation. The control unit 4 includes an operating position of the shift lever 14, an accelerator opening α, a depressed state of a brake pedal (not shown), a rotational speed Ne and a vehicle speed V.
The shift / select position sensor 6 detects the shift / select position and sets the optimum gear position based on the shift pattern based on the shift / select position.
Control. The synchronous state of the sleeve gear 29 is detected from the relationship between the input and output rotational speeds detected by the sensors 7 and 8. At the time of shifting, the throttle actuator 1
The throttle opening .theta. Is narrowed to a predetermined opening position by 1 and the exciting current of the electromagnetic clutch 2 is set to 0 so that the stepped transmission 3 is in a power-off state to switch gears. Next, a specific correction method according to the first embodiment of the present invention will be described with reference to the characteristic diagram of the relationship between the clutch exciting current and the clutch transmission torque shown in FIG. In FIG. 2, the solid line indicates the relationship between the clutch excitation current and the clutch transmission torque when the product is new, and the broken line indicates the relationship between the clutch excitation current and the clutch transmission torque by the clutch control device of the automatic transmission according to the first embodiment. The graph shows the clutch excitation current-clutch transmission torque relation characteristic after aging obtained by repeatedly changing the characteristic. Point A on the solid line in the figure is a point when the vehicle speed reaches the creep target vehicle speed during the previous creep running, and point B is a point when the vehicle speed reaches the creep target vehicle speed during the current creep running. It is. Assuming that the clutch transmission torques at the time when the target vehicle speed is reached are equal, the intersection of a straight line passing through the point B with a constant clutch exciting current and a straight line passing through the point A with a constant clutch transmission torque is the point after the change. That is, the relationship between the clutch excitation current and the clutch transmission torque is corrected to the characteristic indicated by the dotted line passing through the changed point. In the above description, the point A on the solid line
Although the points B and B are taken as examples, the relationship characteristic of the clutch exciting current-clutch transmission torque after aging, which is a broken line, can be newly corrected by the same method. FIG. 3 is a timing chart showing a state in which the vehicle is stopped and a state in which it is creeped. In FIG. 3, the solid line shows the running state of the clutch when new, and the broken line shows the running state of the clutch after aging. Since the clutch after the aging has a smaller value of the clutch transmission torque for the same clutch exciting current as compared with the clutch when it is new, the rate of increase (acceleration) of the vehicle speed is small (solid line and broken line of the vehicle speed in FIG. 3). See). According to the clutch control device for an automatic transmission according to the first embodiment, the integral characteristic ΔA is added to the clutch excitation current in the feedback control by changing the relationship characteristic between the clutch transmission torque and the clutch excitation current, and the creep is increased. The creep exciting current supplied to the electromagnetic powder clutch when the target vehicle speed is reached is increased. The clutch control device for an automatic transmission according to the present invention allows a vehicle to creep when a shift position is within the travel range and there is no detection by a brake switch and an accelerator position. The clutch transmission torque-so that the value of the clutch transmission torque when the actual vehicle speed reaches the target speed is the value of the clutch transmission torque when the actual vehicle speed during the previous creep traveling reaches the target speed. By correcting the relationship characteristic of the clutch excitation current, a good creep feeling can be obtained without a difference in creep force due to aging of the clutch or variation in characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of Embodiment 1 of the present invention. FIG. 2 is a characteristic diagram showing a relationship between a clutch exciting current and a clutch transmission torque according to the first embodiment of the present invention; FIG. 3 is a timing chart of the first embodiment of the present invention. [Description of Signs] 1 engine, 2 electromagnetic powder clutch, 3 stepped transmission (synchronous mesh transmission), 4 control unit (control means), 8 output rotational speed sensor (vehicle speed sensor), 13 accelerator position sensor, 14 Shift lever (range switch), 15 engine rotation sensor, 17 brake switch.

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Claims (1)

Claims 1. A clutch transmission torque calculated according to a deviation signal obtained by a closed loop control based on a deviation between a target vehicle speed and an actual vehicle speed, based on a clutch transmission torque-clutch excitation current relationship characteristic. A clutch control device for an automatic transmission that converts a clutch excitation current and supplies the clutch excitation current to an electromagnetic powder clutch to cause the vehicle to creep. The engine includes an engine rotation sensor that detects an engine rotation speed, and a brake pedal. A brake switch for detecting a depressed state; a range switch for detecting a shift position of any of a travel range, a neutral range, and a reverse range; and an accelerator position sensor for detecting an accelerator pedal depression amount as an accelerator opening. Output rotation speed of synchronous mesh transmission A vehicle speed sensor that detects the vehicle speed as a vehicle speed; and a control unit that switches a shift state of the synchronous meshing transmission based on detection signals of the engine rotation sensor, the brake switch, the range switch, the accelerator position sensor, and the vehicle speed sensor. The control means causes the vehicle to creep when the shift position is in the travel range and there is no detection by the brake switch and the accelerator position, and the actual vehicle speed by the vehicle speed sensor reaches a target speed. The relationship between the clutch transmission torque and the clutch excitation current is corrected so that the value of the clutch transmission torque at the time of the above-described operation becomes the value of the clutch transmission torque when the actual vehicle speed during the previous creep running reaches the target speed. A clutch control device for an automatic transmission.