JPS63140152A - V belt type continuously variable transmission - Google Patents

Abstract

PURPOSE:To enable a speed change gear ratio to be set large by putting a bush into the shaft-hole of a movable sheave and making one end of the bush protrude toward the fixed sheave side. CONSTITUTION:A drive pulley 1 is made up of a fixed sheave 2 and movable sheave 3. The fixed sheave 2 is screw-joined on a boss portion 2a put on a drive shaft 4. The movable sheave 3 is slidably shaft-supported on the boss portion 2a through a bush 3b which is made of copper alloy and is a little longer than the depth of a shaft-hole 3a, and makes the effective diameter of a V belt 5 change through approaching to or receding from the fixed sheave 2. Hereupon, when the drive shaft 4 is at a lower speed than planned, the movable sheave 3 is at the left-end position of the drawing, and the Ve belt 5 is released from the restraint of both sheaves 2, 3 and is support-succeeded by the bush 3b. The movable sheave 3 is moved to the right part by speed rise, and the effective diameter of the pulley 1 is gradually increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to an improvement of a variable diameter pulley for a V-belt type automatic transmission.

[Conventional technology and its problems]

Conventionally, V-belt type automatic transmissions have V-belt type automatic transmissions, as shown in Figure 4.
The pulley of the belt is composed of a fixed sheave and a movable sheave that advances and retreats in the axial direction with respect to the fixed sheave, and the two sheaves move closer or farther apart depending on the tension of the V-belt, making the effective diameter larger or smaller. When the speed of one drive shaft falls below a predetermined value, the V-belt is expanded to a width greater than the width of the V-belt to cut off transmission of power, and the V-belt is also used as a clutch. Additionally, when the clutch is disengaged, slippage may occur between the V-belt and the drive shaft, causing wear and tear. To prevent this, ball bearings are interposed between both sheaves. (For example, Utsukai Showa 50-3
5966).

In such a device, since the minimum diameter of the pulley is limited by the size K of the ball bearing, there is a problem that the speed ratio cannot be changed significantly.

[Object of the invention and summary of means for solving the problem] The purpose of this invention is to eliminate the above-mentioned problems, prevent damage to the V-belt, and provide a V-belt automatic transmission that can greatly change the gear ratio. The drive pulley is configured with a variable diameter, consisting of a fixed sheave fixed to the boss and a movable sheave that is pivotally supported by the boss and moves forward and backward with respect to the fixed sheave. The feature is that a bush longer than the depth of the hole is fitted, and one end of the bush protrudes toward the fixed sheave side.

[Effect]

When the clutch is disengaged by widening the space between the fixed sheave and the movable sheave, the belt is supported by a small diameter bush that protrudes from the movable sheave toward the fixed sheave, so a ball bearing is installed in this part. Compared to the conventional one used, the diameter of both sheaves can be made smaller, so
A large gear ratio can be obtained without increasing the maximum diameter of the sheave.

[Embodiment] The present invention will be explained below with reference to the illustrated embodiment. In the figure, 1 is a drive pulley of a V-belt type automatic transmission. The drive pulley 1 is made by casting an aluminum alloy and has a dish shape. A fixed sheave 2 and a movable sheave 3 facing each other in the plane of
It is made up of.

That is, the fixed sheave 2 is screwed onto a boss portion 2a that is fitted onto the drive shaft 4, and is prevented from loosening by a lock nut 2b. Further, the movable sheave 3 is slidably supported on the boss portion 2a via a bushing 3b made of adjustable alloy, which is slightly longer than the depth of the shaft hole 3a and is fitted with the shaft hole 3a with a relatively small gap. The effective diameter of the V-belt 5 wound close to and away from the fixed sheave 2 and wound between them is changed in size.

Three guide bars 3c are protruded from the back of the movable sheave 3, and an auxiliary frame 6 made of aluminum alloy is connected to the other end of the guide bar 3C by a pole 6m, which is pivotally supported on the small diameter portion of the boss portion 2a. It is integrated.

3d is a core portion constituting the guide bar 3c, the outer periphery of which is covered with a cylinder 3@ made of synthetic resin. A concave groove 3f is provided on the back surface of the movable sheave 3, located between each guide bar 3c, and a centrifugal weight 7 is supported by its support shaft 7a.

Reference numeral 8 denotes a pressure receiving member disposed between the movable sheave 3 and the auxiliary frame 3d.The pressure receiving member 8 is screwed to the small diameter portion of the boss portion 21, and the movable sheave 3 is constantly fixed by a return spring 9 on the back side. It is biased in the direction of pulling away from the sheave 2. 8a
A sliding member made of synthetic resin is attached to the pressure receiving member 8 with a pin 8b, and comes into contact with the centrifugal weight 7 and supports the pushing force thereof.

Next, to explain the operation of this embodiment, while the drive shaft 4 is operated at a lower speed than expected, the centrifugal weight T rotates outward and comes into contact with the sliding member 8a, but the centrifugal force Since the movable sheave 3 is not large, the movable sheave 3 is at the left end position as shown in Figure 1.
Further retreat is restricted by the pressure receiving member 8.

Therefore, the V-belt 5 is released from the restraints of both sheaves 2 and 3 and is supported by the bush 3b. Since the bush 3b is not fixed to the movable sheave 3 or the boss portion 2a, the V-belt 5
Even if the drive shaft 4 is rotating due to the friction between the drive shaft 4 and the V-belt 5, it remains in a stopped state, so that no unnecessary friction occurs between the drive shaft 4 and the V-belt 5, and there is no wear and tear.

When the speed of the drive shaft 4 is increased to start running the vehicle, the centrifugal weight 7 further swings outward, causing the sliding member 8a to
A strong pressure is applied to the pressure receiving member 8 through the pressure receiving member 8, and the movable sheave 3 is moved to the right in the figure by the reaction force.

Due to this action, the 5V belt 5 is pressed between the fixed sheave 2 and the movable sheave 3, and power is transmitted by the friction. Furthermore, as the speed of the drive shaft 4 further increases, as is obvious, the movable sheave 3 approaches the fixed sheave 2 side further, increasing the effective diameter of the drive pulley 1, and reducing the reduction ratio of the transmission to reduce the speed of the vehicle. Increase speed.

〔Effect of the invention〕

As described above, the present invention comprises a drive pulley having a variable diameter with a fixed sheave fixed to a boss portion and a movable sheave that is pivotally supported by the boss portion and moves back and forth with respect to the fixed sheave, and the shaft hole of the movable sheave. A bushing longer than the depth of this shaft hole is fitted into the shaft hole, and one end of the bushing protrudes toward the fixed sheave, so when the speed of the drive pulley is low and power transmission is cut off, the V-belt 5 is driven. It is supported by a bushing supported on the shaft, so there is no wear and tear between it and the drive shaft. Further, since the bush has a small diameter, it is possible to set a large gear ratio without increasing the maximum diameter of both sheaves.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a sectional view of a drive pulley, and FIG. 2 is a partially cutaway front view. 2e...Fixed sheave, 2a...Fist boss part, 3...
- Movable sheet, 3b--Bush, 5--V belt, 7-φ--Centrifugal weight.

Claims (3)

[Claims] (1) The drive pulley has a variable diameter configuration with a fixed sheave fixed to the boss and a movable sheave that is pivotally supported by the boss and moves forward and backward with respect to the fixed sheave. A V-belt type automatic transmission in which bushes that are longer than the depth are fitted and one end of the bush protrudes toward the fixed sheave side. (2) The V-belt automatic transmission according to claim 1, wherein the movable sheave is cast from an aluminum alloy, and the bushing is made from a copper alloy. (3) The V-belt type automatic transmission according to claim 1, wherein the movable sheave is configured to slide in accordance with the swinging of a centrifugal weight pivotally mounted on the back surface.