JPH06300101A - Speed change control method for v-belt continuously variable transmission - Google Patents

Abstract

PURPOSE:To increase the service life of a belt by preventing an excessive thrust from being applied to the belt when a gear is shifted up. CONSTITUTION:A control circuit 15 of a V-belt continuously variable trausmission in which a pulley-to-pulley distance is made variable through a motor 6 controls a current supplied to the motor 6 below a motor current value, which is set according to the pulley-to-pulley distance stored beforehand, when the motor 6 is driven in the direction for reducing the pulley-to-pulley distance.

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.

[0002]

2. Description of the Related Art Conventionally, in a continuously variable transmission for a vehicle shown in FIG. 5, a belt 4 is hung between a drive pulley 2 and a driven pulley 3 of the continuously variable transmission 1 to drive the pulley 2. Input shaft 2A of the driven pulley 3 is connected to an output mechanism of the engine (not shown).
Is connected to the drive system. Since the 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, the continuously variable transmission 1 has a sliding position of the movable pulley 5. The shift control is performed by the control of.

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 shaft 9A, the gear 9 is rotationally driven. As a result, the slider 11 having a gear that meshes with the gear 9 is rotationally driven. The shaft of the slider 11 has a screw,
The screw moves the slider 11 in the axial direction of the drive pulley. As a result, the slider 11 and the bearing 11
The movable pulley 5 connected via A is slid along the input shaft 2A.

A position sensor 12 that detects the sliding position of the movable pulley 5 is connected to a slider 11 that meshes with the gear 9. The position sensor 12 is configured so that the internal resistance changes as the slider 11 moves. As a result, a voltage signal corresponding to the sliding position of the connected movable pulley 5 is output via the slider 11 and the bearing 11A.

A rotation sensor 13 is arranged on the outer peripheral portion of the input shaft 2A, 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 and 14 are connected to a control circuit 15, and a microcomputer incorporated in the control circuit 15 inputs a signal from the position sensor 12 to cause the movable pulley 5 to move. The sliding position can be recognized, and the actual gear ratio can be calculated by inputting the signals from the rotation sensors 13 and 14. The control circuit 15 is connected to a motor drive circuit 16 that supplies a drive current to the motor 6, and sends a control signal for sliding the movable pulley 5 to a target position to the motor drive circuit 16. Output. When the motor drive circuit 16 receives the control signal, the motor drive circuit 16 drives the motor 6 to slide the movable pulley 5 to the target position.

In the memory of the microcomputer incorporated in the control circuit 15, a three-dimensional map showing the relationship between the throttle opening, the vehicle speed and the target ratio (target gear ratio) is shown stepwise as shown in FIG. It is stored. Therefore, the control circuit 15 includes a position sensor 12 and a rotation sensor 1.
In addition to the signals from 3 and 14, the throttle opening signal from the throttle opening sensor and the vehicle speed signal from the vehicle speed sensor are input.

In the V-belt type continuously variable transmission having such a structure, the control circuit 15 looks up the target ratio from the vehicle speed and the throttle opening on a three-dimensional map as described above, and the motor 6 is correspondingly looked up. Although it is controlled, when shifting up, the movable pulley 5 is moved to the right side in FIG. 5, and the movable pulley 5 presses the belt 4 to move the belt 4 to the upper side in the figure. If the pressing force of the belt against the belt 4 is too strong,
There is a problem that the life of the V-belt 4 is reduced.

[0009]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned problems of the prior art, and it is possible to maintain a proper pressing force against the belt at the time of shift-up and to improve the belt life. The purpose of the present invention is not to provide a control method, and the gist thereof is to provide a drive pulley attached to an input shaft driven by an engine, a driven pulley attached to an output shaft, and a winding between the drive pulley and the driven pulley. A V-belt continuously variable transmission, wherein the pulley spacing of at least one of the drive pulley and the driven pulley is variably configured via a motor by a control circuit. When driving the motor in the direction of narrowing the pulley interval, the current supplied to the motor is adjusted according to the pulley interval stored in advance. It is to control the following set motor current value Te.

[0010]

[Operation] The motor current value for obtaining the thrust of the pulley to the extent that the belt does not slip is pre-stored in the control circuit, and the actual current of the motor at the time of gear shift control in the upshift direction is stored in the control circuit. It detects the value and compares the actual current value of this motor with the correct stored current value of the motor to control the actual motor current value in the lower direction so that the pulley does not press the belt too hard. Control.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. In this example, the continuously variable transmission of FIG. 5 is configured such that the actual current value of the motor 6 is detected and the detected current value is fed back to the control circuit 15. Has a map of limiter values as shown in FIG. 3 stored in advance. This is because when the motor 6 is driven to move the movable pulley 5 to the right side in FIG. 5 to shift up, when the current value of the motor 6 is high, the movable pulley 5 strongly presses the belt 4 to extend the belt life. In order to reduce the pressure, the movable pulley 5 is controlled so as to reduce the pressing force against the belt 4, and the thrust of the movable pulley 5 to the right side in the drawing (the pressing force against the belt 4) is as shown in FIG. If the current supplied to the motor 6 is large, the thrust also increases with the motor current value. Therefore, the actual current value of the motor 6 is detected, and if this motor current value is high,
The control is intended to keep the current value low.

As shown in FIG. 2, the speed change speed is proportional to the thrust of the movable pulley 5. In FIG. 3, the minimum speed of the movable pulley 5 is such that the belt 4 does not slip for each speed ratio. The thrust force (required thrust force) is mapped on the basis of experimental values, and a limiter value slightly higher than the required thrust force to the extent that the belt 4 does not slip is shown in the map, and the control circuit 15 of FIG. The limiter value of the map is picked up, the motor current value of FIG. 4 corresponding to this limiter value is obtained, and the motor current value is controlled so as not to exceed the limiter value. That is, the motor current value (limiter value) set according to the pulley interval is controlled to be equal to or less than the required thrust force to prevent the V belt 4 from slipping so that the V belt 4 is not excessively thrust at the time of upshifting. The motor current is controlled so that the movable pulley 5 presses the belt 4 with a slightly higher thrust.

The contents of the control will be explained based on the flow chart of FIG. 1 which embodies the control by the control circuit 15. In step S1, whether or not the vehicle is running is detected from a vehicle speed sensor and the vehicle is stopped. For example, in step S2,
The supply of electric current to the motor 6 is stopped to stop the motor. If the car is running, in step S3,
It is determined whether the shift is up. This is detected by the signal from the position sensor 12.

If it is not in the upshift state, the downshift control or the motor stop control is performed in step S4. If it is in the upshift state, the actual motor current is detected in step S5. Further, in the control circuit 15, in step S6, as shown in FIG.
Pick up and read the limiter value of the map shown in. Next, in step S7, the detected motor current value is compared with the motor current value of FIG. 4 corresponding to the limiter value read in step S6. If the actual current value of the motor 6 is larger, the motor current supplied from the drive circuit 16 to the motor 6 is controlled in step S8 to be decreased, and the actual current value of the motor and the reading value are read. If the current value corresponding to the limiter value is the same or the actual motor current value is smaller, the shift-up control by normal motor control is performed in step S9.

As described above, in this embodiment, during the shift-up control, the pushing force against the belt 4 is limited to a pulley thrust slightly higher than the lowest pulley thrust that does not cause slippage, and the shortening of the belt life is effectively prevented. be able to.

[0016]

According to the present invention, when the control circuit drives the motor in the direction of narrowing the pulley interval, the current supplied to the motor is set to the motor current value set according to the pulley interval stored in advance. Since it is decided to control below, the pulley is pressed against the belt with a thrust that is slightly larger than the thrust that does not cause the belt to slip, and the belt life is improved by preventing excessive thrust on the belt. It has the effect that

[Brief description of drawings]

FIG. 1 is a flowchart of a shift control of this example.

FIG. 2 is a diagram showing a relationship between a pulley thrust and a shift speed.

FIG. 3 is a map showing the relationship between the required thrust of the pulley and the ratio to the extent that the belt does not slip.

FIG. 4 is a diagram showing a relationship between pulley thrust and motor current.

FIG. 5 is an overall configuration diagram of a continuously variable transmission of a vehicle.

FIG. 6 is a three-dimensional map diagram showing the relationship among the throttle opening, the vehicle speed, and the target ratio in stages.

[Explanation of symbols]

 1 continuously variable transmission 2 drive pulley 3 driven pulley 4 belt 5 movable pulley 6 motor 11 slider 12 position sensor 15 control circuit 16 motor drive circuit

Claims (1)

[Claims] 1. A drive pulley attached to an input shaft driven by an engine, a driven pulley attached to an output shaft, and a V-belt wound between the drive pulley and the driven pulley. At least one of the drive pulley and the driven pulley has a pulley interval which is variable by a control circuit via a motor.
In the belt type continuously variable transmission, when the control circuit drives the motor in a direction of narrowing the pulley interval, a current supplied to the motor is set according to the pulley interval stored in advance. A shift control method in a V-belt type continuously variable transmission characterized by controlling to a current value or less.