JP2012241812A - Continuously variable transmission and actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive continuously variable transmission and actuator.SOLUTION: The continuously variable transmission including a fixed sheave that is fixed to a pulley shaft and is integrally rotated, a movable sheave that is movably supported in the axial direction along the pulley shaft, a belt disposed between the fixed sheave and the movable sheave, and an actuator that varies a pulley groove width by moving the movable sheave in the axial direction, wherein the actuator is composed of an electrically operated motor, a speed reducer that transmits a turning force generated by the electrically operated motor, a nut that inputs the motive power of the electrically operated motor through the speed reducer, a screw shaft that is displaced in the axial direction in response to the rotation of the nut, and a swing member one end of which is connected to the screw shaft, the other end of which is connected to the movable sheave, and which is swingable. The actuator has no sensor.

Description

  The present invention relates to a continuously variable transmission, in particular, a V-belt continuously variable transmission for a vehicle and an actuator suitable for use in the same.

  Conventionally, as shown in Patent Document 1, a pulley having an electric motor, a fixed sheave fixed to the pulley shaft, and a movable sheave supported on the pulley shaft so as to be movable in the axial direction, and movable by the rotational force of the electric motor There has been proposed a continuously variable transmission including an actuator that changes the pulley groove width by displacing the sheave in the axial direction and a gear mechanism that transmits the rotational force of the electric motor to the actuator.

JP 2009-79759 A

  Patent Document 1 describes that an actuator is provided with a sensor, the amount of axial displacement is measured, and the behavior is controlled. However, there is room for improvement in such a configuration in terms of the cost of the sensor itself and its peripheral parts, and further the assembly cost thereof.

  In view of the above, an object of the present invention is to provide an inexpensive continuously variable transmission and an actuator used for the continuously variable transmission.

The above object of the present invention can be achieved by the following constitution.
(1) An input shaft for inputting rotation to the pulley shaft, a fixed sheave fixed to the pulley shaft and integrally rotated, a movable sheave supported so as to be movable in the axial direction along the pulley shaft, and the movable sheave A driving pulley comprising the fixed sheave, a belt disposed between the fixed sheave and the movable sheave, a driven pulley connected to the driving pulley via the belt, and the driven side In a continuously variable transmission having an output shaft that outputs rotation shifted through a belt to a pulley, and an actuator that moves the movable sheave in an axial direction to vary a pulley groove width,
A sensor for detecting the rotational speed of the input shaft and the output shaft;
A continuously variable transmission, wherein the actuator is controlled based on the rotational speeds of the input shaft and output shaft detected by the sensors.
(2) The actuator includes an electric motor, a speed reduction mechanism that transmits a rotational force generated by the electric motor, a nut that inputs power of the electric motor via the speed reduction mechanism, and a rotation amount of the nut A screw shaft that is displaced in the axial direction, and a swing member that has one end connected to the screw shaft and the other end connected to the movable sheave and is swingable.
The continuously variable transmission according to (1), wherein the actuator is not provided with a sensor.
(3) An electric motor, a speed reduction mechanism that transmits the rotational force generated by the electric motor, a nut that inputs power of the electric motor via the speed reduction mechanism, and an axial direction according to the amount of rotation of the nut An actuator having a screw shaft that is displaced and provided with no sensor.

  According to the present invention, since the sensor is not provided in the actuator, the cost of the sensor itself and its peripheral parts, and further the assembly cost thereof can be suppressed, and a low-cost actuator and continuously variable transmission can be realized.

It is a block diagram which shows embodiment of this invention. It is a flowchart which shows the control method of the actuator which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a belt type continuously variable transmission according to the present invention. FIG. 2 is a flowchart showing a method for controlling the actuator of FIG.

  A belt type continuously variable transmission 1 shown in FIG. 1 is coaxially connected to a drive side pulley 4 that is coaxially connected to a crankshaft 3 (input shaft) extending from an engine 2 and an output shaft 6 that transmits power to wheels 5. The driven pulley 7, the endless V belt 8 that transmits power from the driving pulley 4 to the driven pulley 7, and the actuator 9 that changes the winding radius of the V belt 8 around the driving pulley 4. .

  The drive pulley 4 includes a fixed sheave 41 that is fixed to the crankshaft 3 and a movable sheave 42 that can approach and separate from the fixed sheave 41. The movable sheave 42 is driven in the axial direction by the actuator 9 in order to change the width of the belt groove formed between the fixed sheave 41 and the movable sheave 42, that is, the winding radius, so that the V-belt 8 is wound.

  The actuator 9 inputs the power of the electric motor via the electric motor, a speed reduction mechanism that transmits the rotational force generated by the electric motor, and the speed reducer as disclosed in, for example, Japanese Patent Application Laid-Open No. 2009-79759. A nut, a screw shaft that is displaced in the axial direction according to the amount of rotation of the nut, and a swinging member that has one end connected to the screw shaft and the other end connected to the movable sheave 42 and is swingable. Have. That is, the movable sheave 42 moves in the axial direction by the rotational force of the motor of the actuator 9, and the winding radius changes.

  The driven pulley 7 includes a movable sheave 71 and a fixed sheave 72 and is disposed on an axis parallel to the driving pulley 4. In the case of deceleration, the movable sheave 42 of the driving pulley 4 is driven in a direction approaching the fixed sheave 41, and the movable sheave 71 of the driven pulley 7 connected by the V belt 8 is driven so as to be separated from the fixed sheave 72. The As a result, the winding radius of the V-belt 8 of the driving pulley 4 increases, the winding radius of the driven pulley 7 decreases, and the rotational speed of the output shaft 6 decreases relative to the rotational speed of the crankshaft 3. Deceleration can be realized. The reverse is true for increased speed.

  The rotation of the engine input from the crankshaft 3 is shifted by the driving pulley 4 and the driven pulley 7 and output to the output shaft 6. The output shaft 6 is connected to the axle via a reduction gear (not shown) or the like, and the wheel 5 is rotationally driven by the rotation output to the output shaft 6.

  The actuator 9 that drives the driving pulley 4 is not provided with a sensor. An input side sensor 31 and an output side sensor 61 are provided at positions where the rotational speeds of the crankshaft 3 and the output shaft 6 can be detected. The crankshaft 3 and the output shaft 6 detected by the input side sensor 31 and the output side sensor 61. , The amount of rotation of the motor of the actuator 9 is controlled as shown in FIG.

Hereinafter, this control method will be described.
First, the rotational speeds of the crankshaft 3 and the output shaft 6 detected by the input side sensor 31 and the output side sensor 61 are sent to the control unit 10 (FIG. 1), and the gear ratios at the driving side pulley 4 and the driven side pulley 7 are sent from these. Is calculated (step S1). Next, the difference between the calculated gear ratio and the required gear ratio is calculated (step S2), and the rotation amount of the motor of the actuator 9 is controlled (step S3).

  As a result, since the gear ratios of the driving pulley 4 and the driven pulley 7 are directly detected and controlled, the gear ratio can be controlled more accurately than when sensing and controlling is performed by the actuator 9 alone. Moreover, since it is not necessary to provide a sensor in the actuator 9, the cost of the sensor itself and its peripheral parts, and further the assembly cost thereof can be suppressed, and a low-cost actuator and continuously variable transmission can be realized.

  In the above description, the input sensor 31 detects the rotational speed of the crankshaft 3, but it may also detect the rotational speed of the crankshaft 3 and a portion having a constant gear ratio. The same applies to the output side sensor 61. The input side sensor 31 can also be used as a so-called engine speed measurement sensor, and the output side sensor 61 can also be used as a vehicle speed measurement sensor.

  The actuator 9 is preferably arranged in parallel on an axis parallel to the driving pulley 1. Thereby, since the axial displacement of the screw shaft is converted into the axial displacement of the movable sheave 42 by the swing member, the inertia of the nut can be suppressed, and the pulley width of the driving pulley 4 can be controlled at high speed. Can be easily performed. Further, by interposing the swing member, even if the movable sheave 42 is tilted by the biasing force of the V-belt 8, the tilt of the screw shaft is not caused and the fatigue life of the screw shaft and the nut is reduced. Can be controlled.

DESCRIPTION OF SYMBOLS 1 Belt type continuously variable transmission 2 Engine 3 Crankshaft 4 Drive side pulley 5 Wheel 6 Output shaft 7 Driven side pulley 8 V belt 9 Actuator 10 Control part

Claims (3)

An input shaft for inputting rotation to the pulley shaft, a fixed sheave fixed to the pulley shaft and integrally rotated, a movable sheave supported so as to be movable in the axial direction along the pulley shaft, and the movable sheave and the fixed A driving pulley comprising a sheave, a belt disposed between the fixed sheave and the movable sheave, a driven pulley connected to the driving pulley via the belt, and the driven pulley to the driven pulley In a continuously variable transmission having an output shaft that outputs rotation shifted through a belt and an actuator that moves the movable sheave in the axial direction to vary the pulley groove width,
A sensor for detecting the rotational speed of the input shaft and the output shaft;
A continuously variable transmission, wherein the actuator is controlled based on the rotational speeds of the input shaft and output shaft detected by the sensors. The actuator includes an electric motor, a speed reduction mechanism that transmits a rotational force generated by the electric motor, a nut that inputs power of the electric motor via the speed reduction mechanism, and an axial direction according to a rotation amount of the nut A screw shaft that displaces to the screw shaft, and a swinging member that has one end connected to the screw shaft and the other end connected to the movable sheave and is swingable.
The continuously variable transmission according to claim 1, wherein the actuator is not provided with a sensor. An electric motor; a speed reduction mechanism that transmits a rotational force generated by the electric motor; a nut that inputs power of the electric motor via the speed reduction mechanism; and a screw that is displaced in an axial direction in accordance with an amount of rotation of the nut A shaft,
An actuator characterized in that no sensor is provided.

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