JPH08226507A - Controlling method for speed change of continuously variable transmission - Google Patents

Abstract

PURPOSE: To enable slip of a belt to be well restrained when the rapid reacceleration is performed from the steady traveling. CONSTITUTION: In a controlling method for speed change of a continuously variable transmission, wherein the target ratio of a V-belt type continuously variable transmission is determined, and the speed change ratio of a pulley of the transmission is controlled by driving a motor 6 for driving the transmission on the basis of the target ratio so as to become the target ratio, the motor 6 is temporarily stopped by judging the belt slip when the difference between the rotational ratio of the rotation of a driving pulley 2 of the transmission to the rotation of a driven pulley 3 and the speed change ratio is larger than the prescribed position in the driving process of the motor 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control method for a V-belt type continuously variable transmission of a vehicle.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG.
The relationship between throttle opening, vehicle speed and target ratio was shown 3
It is possible to control the continuously variable transmission by determining the target ratio of the V-belt type continuously variable transmission by looking up the dimension map, and driving the motor for driving the transmission based on the target ratio. Has been done. This motor slides the movable pulley of the drive pulley of the continuously variable transmission.
The rotation ratio changes according to the sliding position of the movable pulley. That is, the continuously variable transmission is composed of a drive pulley and a driven pulley to which the rotation from the drive pulley is transmitted via a belt. The controlled driving force is output. A pulley position sensor is provided to detect the sliding position of the movable pulley of the drive pulley, and the pulley position sensor outputs the output signal of the pulley. The gear ratio is detected. Further, in order to recognize the rotation ratio of the drive pulley and the driven pulley, a sensor for detecting the rotation speed of each pulley shaft is provided.

In the above construction, as shown in FIG. 4, when the vehicle is in a steady running state, the target ratio shown in FIG. 1 is determined from the throttle opening and the vehicle speed, and the motor is driven so as to attain this target ratio a. Then, the movable pulley of the drive pulley is slid to control the gear change ratio b of the transmission pulley to the target ratio a, and the drive pulley and the driven pulley are controlled.
The rotation ratio c of the Lee follows this curve and draws a curve that is almost the same as the pulley gear ratio b, but from this steady running, the driver of the vehicle suddenly stepped on the accelerator to achieve rapid reacceleration. Sometimes, the target ratio a is P1 in FIG.
Up to P2, the movable pulley of the drive pulley rapidly slides away from the fixed pulley via the motor so as to follow the raised target ratio a. Although it moves dynamically, the contact force between the belt and the movable pulley weakens due to the sudden sliding movement, and the belt slips, so that smooth reacceleration cannot be obtained.
It should be noted that when the belt slips, the driven
The rotation of the drive pulley is increased as compared with the rotation of the reel, and the rotation ratio is rapidly increased. It should be noted that such a belt slip phenomenon may occur when the vehicle is 20 to 20 degrees after the accelerator is released.
This also occurs when the accelerator is suddenly depressed from the state of traveling at a speed of about 30 km / h to re-accelerate, and there is a problem that good re-acceleration cannot be obtained due to slip.

[0004]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned problems of the prior art, and is a shift control method for a continuously variable transmission capable of suppressing belt slip and obtaining good re-acceleration. The purpose of this is to determine the target ratio of the V-belt type continuously variable transmission, and drive the motor for driving the transmission based on the target ratio to determine the transmission ratio of the transmission. In a gear shift control method for controlling the gear shift ratio of the reel to reach the target ratio, in the driving process of the motor, the rotation of the drive pulley and the rotation of the driven pulley of the transmission are rotated. When the difference between the ratio and the gear ratio is larger than a predetermined position, it is determined that the belt slips, and the motor
Is to stop temporarily.

[0005]

When the belt slips when the accelerator pedal is suddenly depressed from the steady running to perform rapid re-acceleration, the rotation of the drive pulley increases due to the slip and the rotation ratio becomes extremely large. Therefore, the difference between the rotation ratio and the pull-gear ratio at this time is determined, and if the difference is equal to or more than a predetermined value, it is determined that the belt has slipped,
The drive of the motor is temporarily stopped and the belt is pulled
The belt is kept in good contact with the belt and slippage of the belt is suppressed.

[0006]

Next, an embodiment of the present invention will be described. Figure 2
Shows a control configuration of the continuously variable transmission 1 of the vehicle. In FIG. 2, a belt 4 is hung between the drive pulley-2 and the driven pulley-3 of the continuously variable transmission 1. The input shaft 2A of the drive pulley-2 is connected to an output mechanism of an engine (not shown), and the output shaft 3A of the driven pulley-3 is connected to a traveling drive system. A movable pulley 5 is slidably mounted on the drive pulley-2, and the rotational diameter of the belt 4 is variable depending on the sliding position of the movable pulley-5. Gear shift control 1 is controlled by controlling the sliding position of the movable pulley 5.

The movable pulley-5 of the drive pulley-2 is slid by a motor-6. That is, the output gear 7 attached to the output shaft of the motor 6 rotates the intermediate gear 8,
Further, in order to rotate the gear 10 attached to the end of the gear shaft 9A, the gear 9 at the other end is rotationally driven. As a result, the slider 11 that meshes with the gear 9 also rotates.
The shaft portion of the slider 11 has a screw structure, and the rotation of the slider 11 moves the slider 11 in the pulley axial direction. The slider 11 is a bearing 11A.
Since it is connected to the movable pulley 5 through the movable pulley 5, the movable pulley 5 is slid along the input shaft 2A.

A slider 11 meshing with the gear 9 has a position sensor for detecting the sliding position of the movable pulley 5.
12 are connected. This position sensor-12
Is configured so that the internal resistance changes with the movement of the slider 11, and as a result, a voltage signal corresponding to the sliding position of the movable pulley 5 connected via the bearing 11A is transmitted. Output. Therefore, this position sensor
Based on the voltage signal output from 12, the pulley shift ratio is detected.

A rotation sensor is provided on the outer peripheral portion of the input shaft 2A.
13 is provided, and a signal corresponding to the rotation speed of the input shaft 2A is output. Further, a rotation sensor-14 is arranged on the outer peripheral portion of the output shaft 3A, and a signal corresponding to the rotation speed of the output shaft 3A is output.

The position sensor-12 and the rotation sensors-13, 14 are connected to the control circuit 15, and the microcomputer incorporated in the control circuit 15 inputs a signal from the position sensor-12. , The sliding position of the movable pulley 5 can be recognized to detect the pulley gear ratio, and the rotation sensors-13, 1
By inputting the signal from No. 4, it is possible to calculate the rotation ratio with the rotation speed of the output shaft 3A as the denominator and the rotation speed of the input shaft 2A as the numerator. The control circuit 15 uses the mode
A motor drive circuit 1 for supplying a drive current to the motor 6.
6 is connected to the motor drive circuit 16,
A control signal for sliding the movable pulley 5 to the target position is output. When the control signal is input, the motor drive circuit 16 drives the motor 6 and slides the movable pulley 5 to the target position.

The memory of the microcomputer contained in the control circuit 15 stores a three-dimensional map showing the relationship between the throttle opening, the vehicle speed and the target ratio as shown in FIG. Therefore, in addition to the signals from the position sensor-12 and the rotation sensors-13 and 14, the control circuit 15 receives the throttle opening signal from the throttle opening sensor and the vehicle speed signal from the vehicle speed sensor. .

FIG. 3 shows the motor for controlling the shift of the V-belt type continuously variable transmission 1 of the vehicle constructed as described above.
6 is a control flowchart, and the shift control of the control circuit 15 will be described based on this. In the steady running state of the vehicle, the opening signal from the throttle opening sensor and the vehicle speed signal from the vehicle speed sensor are shown. Based on the above, the target ratio is calculated from the three-dimensional map shown in FIG. 1, and the control circuit 15 issues a drive signal to the drive circuit 16 to drive the motor 6 so that the target ratio a shown in FIG. , Position sensor-12
The drive of the motor 6 is controlled so that the pulley gear ratio indicated by b becomes the target ratio a by the detection signal from. Since the belt 4 does not slip during steady running in this case, the rotation ratio c calculated from the signals from the rotation sensors 14 and 13 of the output shaft 3A and the input shaft 2A is the pre-gear ratio b. Although the curve is almost the same as the above, when the driver suddenly depresses the accelerator pedal from this steady running to perform re-acceleration, that is, when kickdown is performed, the accelerator is released at 20 to 30 km / h and the coasting is performed. When the accelerator pedal is suddenly depressed to re-accelerate while the vehicle is running in this state, the target ratio a is in a rapid start-up shift down control state extending from P1 to P2 in FIG. -Ta-
The movable pulley 5 suddenly starts to move to the left in FIG. 2 via 6 in order to follow the target ratio a.

Due to such a sudden shift-down movement of the movable pulley 5 to the left in the figure, the belt 4 may be momentarily lifted up.
When the contact state with the reel 5 becomes loose, the belt 4 slips, and at the time of this slip, as shown in FIG. 4, the rotation of the input shaft 2A rapidly rises and the rotation ratio c sharply increases to P3.
Will be raised to the position. In the control circuit 15, when the rotation ratio c rapidly rises, the ratio difference between the rotation ratio c and the pre-gear ratio b is detected in step S1 in FIG. 3, and this ratio difference is detected in step S2.
When it is determined in step S3 that the belt 4 is slipping, the drive circuit 1 is determined based on the determination in step S3.
A signal is sent to 6 to temporarily stop the motor 6 in step S4.

Since the movement of the movable pulley 5 to the left in the drawing is temporarily stopped by stopping the motor 6, the belt 4
Becomes firmly in contact with the movable pulley 5 and the belt slip is stopped here. Since the control circuit 15 repeatedly performs the control from step S1 to step S4, the rotation ratio c and the pre-gear ratio b.
If the ratio difference between the two is larger than the predetermined value, the motor 6 is stopped to stop the slipping during that time, so that the downshift is performed without causing the belt 4 to slip, and the smooth re-acceleration of the vehicle. Can be obtained. In addition,
When the ratio difference in step S2 is equal to or less than the predetermined value, that is, when the belt 4 is not slipped, the normal gear ratio corresponding to the target ratio a is set so that the target ratio a and the pre-gear ratio b match. Control is performed in step S5.

As described above, in this embodiment, when the accelerator is suddenly depressed from the steady running to kick down to accelerate the vehicle again, the belt is prevented from slipping as in the conventional case, and no slip occurs. Thus, re-acceleration can be smoothly performed, and the operating state of the transmission during kickdown becomes extremely smooth.

[0016]

According to the present invention, the target ratio of the V-belt type continuously variable transmission is determined, and the motor for driving the transmission is driven based on the target ratio, so that the pulley of the transmission is controlled. In a speed change control method for controlling the speed change ratio to reach the target ratio, in the drive process of the motor, the drive speed of the transmission is increased.
When the difference between the rotation ratio of the rotation of the reel and the rotation of the driven pulley and the speed change ratio is larger than a predetermined position, it is judged as a belt slip and the motor is temporarily stopped. Therefore, during a sudden downshift operation in which the accelerator is suddenly depressed from the steady running to perform a rapid re-acceleration, belt slip is suppressed and the continuously variable transmission is operated smoothly without slipping and smoothly re-accelerated. Has the effect of being obtained.

[Brief description of drawings]

FIG. 1 is a three-dimensional map diagram showing a stepwise relationship between a throttle opening, a vehicle speed, and a target ratio.

FIG. 2 is an explanatory diagram of a control configuration of a V-belt type continuously variable transmission of a vehicle.

FIG. 3 is a motor control flow chart.

FIG. 4 is a relationship diagram of a target ratio, a pulley shift ratio, and a rotation ratio.

[Explanation of symbols]

 1 V-belt type continuously variable transmission 2 Drive pulley 3 Driven pulley 4 Belt 5 Movable pulley 6 Motor 9 Gear 11 Slider 12 Position sensor-13 Rotation sensor-14 Rotation sensor- 15 Control circuit 16 Motor drive circuit a Target ratio b Pre-gear ratio c Rotation ratio

Claims (1)

[Claims] 1. A target ratio of a V-belt type continuously variable transmission is determined, and a motor for driving a transmission is driven based on the target ratio so that the gear ratio of the pulley of the transmission is the above-mentioned. In a gear change control method for controlling to achieve a target ratio, in the drive process of the motor, the rotation ratio between the rotation of the drive pulley of the transmission and the rotation of the driven pulley and the gear ratio. A shift control method for a continuously variable transmission, wherein when the difference is larger than a predetermined position, it is determined that a belt slip has occurred and the motor is temporarily stopped.