JPH084864A - Controller of continuously variable transmission - Google Patents

Abstract

PURPOSE:To enhance safety of traveling by controlling the drive pulley diameter into the specific maximum diameter when the vehicle speed is the specific value or more, and into the minimum specific diameter when the vehicle speed is the specific value or less, in failures of a controlling solenoid valve for controlling the driven pulley diameter. CONSTITUTION:In a control circuit 20 of a continuously variable transmission, whether a solenoid SOL2 for controlling a drive pulley 4 is wrong or not is judged. When the result is NO, the normal transmission processing is applied, and the drive pulley pressure P1 is controlled as a function of the vehicle speed (v) and the throttle opening gamma, and the driven pulley pressure P2 is controlled as a function of the gear ratio and torque T. While, when the solenoid is wrong, whether the vehicle speed is the specific value or less or not is judged. When the result is YES, the drive pulley pressure P1 is made into the minimum pressure, and the driven pulley diameter is made into the specific minimum diameter, so as to restore the vehicle speed. When the result is NO, whether the gear ratio is in the low side or not is judged. When the result is NO, the drive pulley pressure P1 is made into the maximum pressure, and the drive pulley diameter is made into the specific maximum value, so as to restore the gear ratio.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a continuously variable transmission, and more particularly to a control device for ensuring vehicle traveling safety even if a drive pulley fails.

[0002]

2. Description of the Related Art A drive transmission system of a vehicle equipped with a continuously variable transmission is connected to a drive shaft directly connected to an engine, a drive shaft to which a drive force from the drive shaft is transmitted via a damper mechanism, and a driven shaft. However, a clutch mechanism for turning on / off the driving force transmission and changing the driving direction depending on the shift position, a continuously variable transmission connected to the clutch mechanism for shifting according to the vehicle speed, the throttle opening, etc. A differential gear that is connected to the transmission to further reduce the rotational speed converted by the continuously variable transmission to amplify the driving force, and an axle that is connected to the differential gear to rotate the wheels.

This continuously variable transmission is provided with a drive pulley connected to the clutch side and a driven pulley connected to the differential gear side. Both pulleys are connected by a V-belt to transmit a driving force.

The continuously variable transmission method is performed by changing the groove width between the pulleys to change the engaging position of the V belt with respect to the diameter of each pulley.

As means for varying the groove width between the pulleys, a cylinder and a piston are provided in each pulley, the hydraulic pressure supplied to the cylinder is controlled, and the piston is slid to vary the groove width (pulley diameter). There is. The control of the hydraulic pressure supplied to the cylinder is performed by a control solenoid valve.

In such a continuously variable transmission, in order to obtain a large torque at the time of starting, a normally open solenoid valve is used as a control solenoid valve on the drive pulley side. (Pulley groove width)
On the other hand, using a normally closed solenoid valve for control on the driven side, the maximum driven pulley diameter (minimum driven pulley groove width) is taken when the vehicle is stopped,
The gear ratio of the continuously variable transmission is kept low when the vehicle is stopped.

Conventionally, for example, in Japanese Patent Laid-Open No. 4-203670,
A main solenoid valve and a sub solenoid valve for controlling the drive pulley or driven pulley are provided, and when the main solenoid valve fails, the hydraulic control can be switched to the sub solenoid valve to continuously perform continuously variable transmission. A hydraulic control circuit for a continuously variable transmission is described.

[0008]

However, in the conventional control device proposed in the above publication, when the solenoid valve for controlling the driven pulley fails, the valve is normally closed. The diameter of the driven pulley that is engaged with the V-belt becomes larger by moving in the direction of decreasing the diameter, and the gear ratio shifts to the low side. For this reason, there is a fear that the vehicle speed may suddenly decrease and the driving safety may be hindered.

Further, in particular, in the hydraulic control circuit for a continuously variable transmission proposed in Japanese Patent Laid-Open No. 4-203670, a double solenoid valve is provided in order to prevent a decrease in vehicle speed due to a failure of the solenoid valve. Although the valve is switched when a failure occurs, there are problems that the vehicle speed decreases due to the time lag when switching the valve, and that the device becomes complicated and downsizing is difficult.

Therefore, the present invention is provided with a fail-safe mechanism which solves the above problems and enhances the safety of running when the solenoid valve controlling the drive pulley fails.
An object of the present invention is to provide a control device for a continuously variable transmission that is simple and downsized.

[0011]

In order to achieve the above object, a hydraulic control device for a continuously variable transmission according to the present invention is a continuously variable transmission for controlling continuously variable pulley diameters of a drive pulley and a driven pulley. And a second control solenoid valve for controlling the diameter of the driven pulley, and a failure of the first control solenoid valve. If the vehicle speed exceeds a predetermined value,
When the drive pulley diameter is larger than the diameter at the time of failure or a predetermined maximum diameter and the vehicle side is below a predetermined value,
A control device for a continuously variable transmission, wherein the drive pulley diameter is set to a predetermined minimum diameter.

Further, in the present invention, preferably, when the vehicle speed at the time of detecting the failure of the second control solenoid valve exceeds a predetermined value and the gear ratio is lower than the predetermined value, the drive pulley diameter is set to a predetermined maximum value. A control device for a continuously variable transmission having a diameter.

[0013]

In the controller for a continuously variable transmission according to the present invention having the above-mentioned structure, even if the driven pulley controlling solenoid valve for controlling the driven pulley diameter is broken due to disconnection, short circuit, or the like, the drive pulley diameter can be reduced. First to control
The control solenoid valve reduces the driven pulley diameter or reduces it to a specified minimum value to prevent a sudden shift of the gear ratio to the low side, which is necessary when the vehicle speed falls below the specified value after a failure occurs and is required for the next start. In order to secure the torque, the drive pulley diameter is reduced or a predetermined minimum value is set to shift the gear ratio to the low side.

As a result, when the driven pulley controlling solenoid valve fails during driving, the stability of the driving is increased without sudden deceleration, and the driver is notified of a failure by an alarm issued by the control device. Recognizing, when the vehicle speed decreases due to accelerator off and falls below a predetermined value,
The gear ratio can be set to the low side to secure the next starting torque.

[0015]

An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In the figure, reference numeral 1 on the left side of the drawing represents a skeleton diagram of a transmission device of a continuously variable transmission for transmitting engine power to drive wheels (not shown), and a control block on the right side of the drawing is a hydraulic control circuit of the continuously variable transmission. It represents.

The transmission 1 is provided with an input shaft 2 connected to an output shaft of an engine via a flywheel damper or the like, a starting clutch 3 composed of a multi-plate clutch 3a and a multi-plate brake 3b, and a clutch 3. A drive pulley (driving pulley) 4 to which the torque of the input shaft 2 is transmitted, and a differential gear 6 that reduces the torque of a driven pulley (driven pulley) 5 and transmits the decelerated torque to the axle.

Further, the input shaft 2 is provided with a rotation sensor 11 for detecting the number of revolutions of the engine, and the drive pulley 4 and the driven pulley 5 are provided with rotation sensors 12, 13 for detecting their respective revolutions. A detector 14 for detecting the on / off state of the accelerator, a sensor 15 for detecting the throttle opening, and a shift position detector 16 for identifying the shift position are provided, and the outputs of these sensors are input to the control circuit 20. . The rotation speed of the output shaft of the clutch 3 is detected by the rotation sensor 12 of the drive pulley 4, and the vehicle speed is the rotation speed of the driven pulley 5 detected by the rotation sensor 13 and the known differential ratio and wheel diameter. It is calculated from Although the vehicle speed is calculated from the driven pulley rotation speed in this embodiment,
The vehicle speed can also be calculated by a vehicle speed sensor that detects the rotational speed of a general wheel.

Next, the hydraulic control circuit will be described with reference to FIG. 1. The pressure oil discharged from the oil pump 21 is passed through the reduction valve 23 to the clutch control valve 2
5 is input to the input port of the clutch control valve 25, the spool position of the clutch control valve 25 is moved by the control pressure from the solenoid valve SOL3, and the clutch hydraulic pressure is output from the oil passage L3 to the starting clutch 3 via the shift valve 26. Do. The solenoid valve SOL3 is a normally open linear solenoid valve, and is controlled by a signal from the control circuit 20.

The shift valve 26 has a shift position (L,
2, D, N, R, P), the spool position is changed to connect the oil passage corresponding to the shift position, and the pressure oil from the oil passage L3 from the clutch control valve 25 is transferred to the multi-plate clutch 3a or It acts on the hydraulic servo of the multi-plate brake 3b.

Pressure oil is supplied to the solenoid valve SOL1 from the reduction valve 23, and the shift control valve 24 composed of a spool valve is connected to the solenoid valve SOL1.
The hydraulic pressure output to the drive pulley 4 is adjusted by the control pressure from. The solenoid valve SOL1 is a normally open linear solenoid valve, and is controlled by a signal from the control circuit 20. More specifically, the control circuit 20 supplies a control signal to the solenoid valve SOL1 with the vehicle speed and the throttle opening as parameters, adjusts the hydraulic pressure output to the drive pulley 4, and changes the pulley width to change the gear ratio. Control to achieve desired fuel economy and acceleration performance.

Pressure oil is supplied from the reduction valve 23 to the solenoid valve SOL2, and the regulator valve 22 for inputting the line pressure adjusts the hydraulic pressure output to the driven pulley 5 by the control pressure from the solenoid valve SOL2. The solenoid valve SOL2 is a normally closed linear solenoid valve, and has a control circuit 20.
Controlled by the signal from. More specifically, the control circuit 20 obtains the pressing force of the pulley required to prevent belt slip from the map corresponding to the torque and the gear ratio, supplies a control signal to the solenoid valve SOL2, and drives the driven pulley 5 Control the hydraulic pressure output to.

The starting clutch 3 includes a clutch control valve 25.
When the multi-plate clutch 3a is engaged by the clutch pressure from the sun gear Sa and the carrier C that rotate integrally with the input shaft 2.
a is directly connected, whereby the torque of the input shaft 2 is transmitted to the drive pulley 4 directly connected to the carrier Ca at a speed reduction ratio of 1, and acts as a forward drive clutch.

When the multi-plate brake 3b is engaged by the clutch pressure from the clutch control valve 25, the ring gear Li
Is fixed to the brake housing, whereby the torque of the input shaft 2 is transmitted from the sun gear Sa to the planetary pinion, and the carrier Ca is reversed at a predetermined reduction ratio, which acts as a reverse drive clutch.

In the N (neutral) range and the P (parking) range, both the clutch 3a and the brake 3b are in the released state, and the engine torque is the drive pulley 4
Not transmitted to.

FIG. 2 is a sectional view showing the mechanism of the transmission device 1 of FIG. The hydraulic pressure of the forward clutch 3a is determined by the through hole 10
By introducing a and 10b into the cylinders 8a and 8b as oil passages, the hydraulic pressure is increased at the time of engagement to cause the pistons 9a and 9b to slide, thereby engaging a plurality of alternately arranged friction members and plates. The torque from the engine is transmitted to the drive pulley 4 via the starting clutch 3 (multi-plate clutch 3a or multi-plate brake 3b). The transmission torque of the starting clutch 3 is determined by the pressing force of the pistons 9a and 9b. Further, in FIG. 2, the piston 4b,
5b slides in the cylinders 4a and 5a in the axial direction to press the movable parts of the drive pulley 4 and the driven pulley 5,
The pulley widths 4c and 5c that determine the diameter of each belt are variably controlled. The hydraulic pressure P1 of the drive pulley 4 is introduced into the cylinder 4a of the two chambers through the oil passage L3, and the piston 4b slides to be set to a predetermined value. Driven pulley 5
Oil pressure P2 is introduced into the cylinder 5a through the oil passage L4, and the piston 5b slides to be set to a predetermined value. The V-belts (4d, 5d) are engaged between the drive pulleys 4 and between the driven pulleys 5 to transmit the driving force therebetween, and the V-shaped belts are responsive to the variable pulley groove widths. The engagement position with respect to the pulley groove on the side portion changes, and the drive is transmitted at a gear ratio corresponding to the drive pulley diameter and the driven pulley diameter.

In order to minimize the drive pulley diameter (the pulley groove width 4C is maximum), the control current supplied to the solenoid valve SOL1 which is a normally open linear solenoid valve is minimized (that is, turned off) to the cylinder 4a. The output drive pulley pressure P1 is minimized, and the movable portion of the drive pulley 4 and the piston 4b are moved rightward in the drawing to minimize the pulley diameter.

Further, in order to maximize the drive pulley diameter (the pulley groove width 4C is the minimum), the control current of the solenoid valve SOL1 which is a normally open linear solenoid valve is maximized (that is, turned on) and output to the cylinder 4a. The drive pulley pressure P1 is maximized, and the movable portion of the drive pulley 4 and the piston 4b are moved leftward in the figure to maximize the pulley diameter.

On the other hand, in order to minimize the driven pulley diameter (the pulley groove width 4C is maximum), the control current of the solenoid valve SOL2, which is a normally closed linear solenoid valve, is maximized (that is, turned on) and output to the cylinder 5a. The drive pulley pressure P2 is minimized, and the movable portion of the driven pulley 5 and the piston 5b are moved leftward in the drawing to minimize the pulley diameter.

Further, in order to maximize the driven pulley diameter (the pulley groove width 4C is the minimum), the control current of the solenoid valve SOL2 which is a normally closed linear solenoid valve is minimized (that is, turned off) and output to the cylinder 5a. The driven pulley pressure P2 is maximized, and the movable portion of the driven pulley 5 and the piston 5b are moved rightward in the figure to maximize the pulley diameter.

Therefore, when the gear ratio is set to the lowest side, the drive pulley pressure P1 becomes the minimum pressure and the driven pulley pressure P2 becomes the maximum pressure. When the gear ratio is set to the highest side, the drive pulley pressure P1 becomes the maximum pressure,
The driven pulley pressure P2 becomes the minimum pressure. The solenoid valves SOL1 and SOL2 are off.

The minimum and maximum pressures of the drive pulley pressure P1 or the driven pulley pressure P2 are naturally different depending on the design of the continuously variable transmission, and the vehicle speed v, the throttle opening θ, the torque T, etc. are traveled. It is also controlled by the state.

Similarly, the minimum and maximum diameters of the drive pulley diameter and the driven pulley diameter differ depending on the design mechanism.

Next, the processing operation of the control device for the continuously variable transmission according to the present invention will be described with reference to the flowchart of FIG. In addition,
The processing shown in FIG. 3 corresponds to the control according to the subject of the present invention in the control of the continuously variable transmission by the ECU, and is represented as a subroutine.

When entering the continuously variable transmission control process,
First, it is determined whether or not the solenoid SOL2 that controls the drive pulley is out of order (step 101). If there is no failure, the normal transmission processing is performed and the drive pulley pressure P1
Is controlled as a function of the vehicle speed v and the throttle opening θ, and the driven pulley pressure P2 is controlled as a function of the gear ratio and the torque T according to the values obtained from the ROM table provided in the control circuit 20 (step 102) and returns to the main routine. The failure mode may be a solenoid disconnection, a short circuit, a valve failure, or the like, and is determined using a voltage sensor, a current sensor, a hydraulic sensor, or the like.

When a failure is detected, the vehicle speed is the predetermined value NO.
It is judged whether it is less than 1 (for example, 10 km / h) (step 10).
3).

When the vehicle speed is equal to or lower than the predetermined value NO.1, the drive pulley pressure P1 is set to the predetermined minimum pressure, and the driven pulley diameter is set to the predetermined minimum diameter, and the operation is restored (step 106). In this case, since the vehicle speed is sufficiently reduced, even if the drive pulley diameter is set to a predetermined maximum value and the gear ratio is shifted to the low side, fluctuations in speed, torque, etc. are small and running stability may be impaired. Therefore, it is possible to secure a gear ratio that can generate the necessary starting torque at the next start.

If the vehicle speed is not lower than the predetermined value N0.1, it is determined whether the gear ratio is on the low side (higher than the predetermined value) (step 104). Here, by determining the value of the gear ratio, if the gear ratio at the time of failure is on the low side (if the gear ratio (driven pulley diameter / drive pulley diameter) is higher than a predetermined value), the process immediately proceeds to step 106. This is preferable because the control can be shifted to (1) to minimize the drive pulley pressure P1 and the drive pulley diameter to minimize the speed ratio to the low side.

When the gear ratio is not lower than the predetermined value (when the gear ratio is lower than the predetermined value), the drive pulley pressure P1 is set to the predetermined maximum pressure and the drive pulley diameter is set to the predetermined maximum value, and the process is returned (step 105). Due to this operation, the gear ratio is maintained at the high side, and rapid fluctuation (deceleration) of the vehicle speed does not occur.

During this processing operation, the drive pulley pressure P1 is set to a predetermined maximum pressure in step 105. However, it is also possible to gradually increase P1 from the immediately preceding pressure to gradually shift the gear ratio to the high side. It is preferable that the fluctuation of
In this case, by adding a certain value from the immediately preceding pressure P1 in step 105, P1 is gradually increased from the immediately preceding value every time the processing routine of the continuously variable transmission is entered, and reaches the maximum pressure. .

During this processing operation, the drive pulley pressure P1 is set to a predetermined minimum pressure in step 106.
It is preferable that P2 is gradually decreased from the pressure immediately before and the transmission ratio is gradually shifted to the low side because the fluctuation of the vehicle speed becomes small. In this case, in step 106, the pressure P1 immediately before is changed.
By subtracting a certain value from, P2 is gradually reduced from the previous value each time it enters the processing routine of the continuously variable transmission, and reaches the minimum pressure.

Further, during this processing operation, the solenoid SO
When L2 is determined to be out of order (step 101), it is also preferable to give an alarm to the driver by voice, video or the like, and turn off the accelerator to stop the operation.

[0043]

As described above, according to the control device of the present invention, when the abnormality of the control system of the driven pulley is detected, that is, when the second control solenoid valve fails, the drive pulley diameter is controlled to change the gear ratio. The drive pulley diameter is reduced and the gear ratio is maintained at a predetermined high side when the driven pulley control system is abnormal, thereby preventing rapid changes in vehicle speed due to the gear ratio shifting to the low side. And to provide a fail-safe mechanism that secures a gear ratio that can generate the next starting torque by increasing the drive pulley diameter or setting a predetermined maximum value when the vehicle speed decreases below a predetermined value to set the gear ratio to the low side. This will enhance the safety of driving.

Further, when the vehicle speed at the time of detecting the failure of the second control solenoid valve exceeds the first predetermined value and the gear ratio is lower than the second predetermined value, the drive pulley pressure P1 is immediately increased. By setting the minimum pressure and the drive pulley diameter to a predetermined maximum diameter, the gear ratio can be set to the lowest side.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of a system according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a transmission device for a continuously variable transmission according to an embodiment of the present invention.

FIG. 3 is a flowchart showing a control process of the control device of the present invention.

[Explanation of symbols]

 1 transmission device 2 input shaft 3 clutch 3a forward clutch (multi-plate clutch) 3b reverse clutch (multi-plate brake) 4 drive pulley 4a cylinder 4b piston 4c drive pulley diameter 4d V belt (drive pulley side) 5 driven pulley 5a cylinder 5b Piston 5c Drive pulley diameter 5d V belt (Driven pulley side) 6 Reduction gear 7 Damper 8a, 8b Cylinder 9a, 9b Piston 10, 10a, 10b Through hole 11 Engine rotation sensor 12 Drive pulley rotation sensor 13 Driven pulley rotation sensor 14 Accelerator -ON / OFF detector 15 Throttle opening sensor 16 Shift position detector 17 Throttle 18 Engine 20 Control circuit 21 Oil pump 22 Regulator valve 23 Reduction valve 24 Change Control valve 25 the clutch control valve 26 shift valve SOL1, SOL2, SOL3 solenoid valve L1, L2, L3, L4 oil passage Sa sun Ca carrier Li ring gear P1 drive pulley pressure P2 driven pulley pressure vehicle speed v throttle opening θ torque T

Claims (2)

[Claims] 1. A control device for a continuously variable transmission for controlling continuously variable speeds by controlling respective pulley diameters of a drive pulley and a driven pulley, and a first control solenoid valve for controlling the drive pulley diameter, and a driven pulley. A second control solenoid valve for controlling the diameter, and when a failure of the second control solenoid valve is detected and the vehicle speed exceeds a predetermined value, the drive pulley diameter is set to the diameter when the failure occurs. A control device for a continuously variable transmission, wherein the drive pulley diameter is set to a predetermined minimum diameter when the vehicle speed is expanded or set to a predetermined maximum diameter and the vehicle speed is equal to or lower than a predetermined value. 2. The vehicle speed at the time of failure detection exceeds a predetermined value, and further,
The control device for a continuously variable transmission according to claim 1, wherein the drive pulley diameter is set to a predetermined minimum diameter when the gear ratio is lower than a predetermined value.