JPH05149402A - Speed change pulley - Google Patents

Abstract

PURPOSE:To gain a speed change pulley whose mechanical efficiency of power transmission is high, and in which the thrust given to a movable pulley piece is always approximate to the optimum value and the durability of a belt or a pulley is superior, by applying a spring mechanism to give the thrust to the movable pulley piece for constituting a speed change pulley, which has advantages of being structurally simple, hard to be broken, and possible to be manufactured at a low price. CONSTITUTION:A compression spring 7 is positioned between a movable pulley piece 5 and a sliding type spring stopper 6 set on the backside of the movable pulley piece 5 as slidable along a shaft 2. Then, a tension spring 10 is positioned between the sliding type spring stopper 6 and an extended part 9a projected from a rigid piece 9 fixed axially along the shaft 2 and extended to the space between the sliding type spring stopper 6 and the movable pulley piece 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed change pulley in which the effective diameter can be changed by changing the width of the pulley, and a speed change gear having a thrust means of a movable pulley piece for constantly generating an appropriate thrust according to the time. Regarding pulleys.

[0002]

2. Description of the Related Art Conventionally, one of the simplest speed change pulleys used for belt type continuously variable speed change is shown in FIG.
As shown in Fig. 4, there is a shift pulley with a stopper fixed to the shaft on the back side of the movable pulley piece, and a spring provided between the stopper and the movable pulley piece. It has the advantage that it can be manufactured at a low cost. The thrust means of the movable pulley piece in this speed change pulley is the thrust force of the spring. In this case, the spring is greatly compressed as the movable pulley piece is pushed by the belt and the width of the pulley is widened, and the elastic repulsion of the spring is caused. The power grows.

[0003]

However, the required thrust of the speed change pulley changes depending on the torque value, so that the thrust applied to the movable pulley piece must increase as the width of the speed change pulley increases. Absent. Generally, when considering driving a car with a power transmission device that uses a belt, when you want to accelerate the car, a large torque is applied and a large load is applied to the belt. The pulley needs to clamp the belt with a large force, and a large thrust must be applied to the movable pulley piece. Also, when the speed of the car is increasing to some extent and the vehicle is traveling at that speed, the torque is small and the load on the belt is small, so the pulley may hold the belt in a small force, and the thrust force to push the movable pulley piece may be small. .

In the speed change pulley using the spring as described above, when the pulley width is narrow regardless of such a change in torque or a change in the load applied to the belt, the spring is in a relatively extended state and thus the thrust force is increased. Is smaller and the pulley width is wider, the spring is compressed and the elastic repulsive force of the spring increases, and the thrust force that pushes the movable pulley piece increases. But,
A large load is applied to the driven pulley when the pulley width is narrow, and a small load is applied to the pulley when the pulley width is wide. Therefore, the magnitude of the thrust that is actually required changes oppositely. FIG. 3 is a diagram showing the relationship between the engine speed and the thrust applied to the movable pulley piece at a predetermined speed. In the conventional speed change pulley as shown in FIG. 2, the spring strength is shown. With the one set for medium / low speed 32 and the one set for high speed 33, the appropriate thrust change 31 required by the movable pulley piece of the speed change pulley in the high speed region or the medium / low speed region 31
It is far off from.

If the thrust of the movable pulley piece is less than the required magnitude, the belt and the pulley will slip and the transmission efficiency will be poor. On the other hand, if the thrust of the movable pulley piece is larger than necessary, the belt and pulley will be worn. There is a problem that the durability is reduced and the transmission efficiency is also deteriorated.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and provide a speed change pulley which gives a movable pulley piece a thrust having a magnitude corresponding to the magnitude of torque or the magnitude of load applied to a belt.

[0007]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a fixed pulley piece that rotates integrally with a shaft,
A variable speed pulley comprising a movable pulley piece movable in at least an axial direction with respect to a shaft, wherein a movable spring piece and a slide type spring stopper provided on the back side of the movable pulley piece and slidable with respect to the shaft. A compression spring is interposed between the sliding spring stopper and a fixed piece that is axially fixed to the shaft, and the extended portion that extends between the slide spring stopper and the movable pulley piece and the slide spring stopper. It is characterized by interposing a tension spring between them.

[0008]

According to the present invention, the compression spring is contracted between the slide spring stopper movably arranged with respect to the shaft on the rear side of the movable pulley piece and the movable pulley piece, and the fixed piece is fixed to the shaft. It consists of an extension that extends between the slide spring stopper and the movable pulley piece, and a tension spring provided between the slide spring stopper.When the pulley width is narrow, the slide spring stopper is the most movable pulley due to the tension spring. It is located on one side and prevents the elastic repulsion force from weakening due to the compression spring expanding.When the width of the pulley becomes wider, the slide spring stopper is pushed by the compression spring and extends the tension spring to the maximum extent. Since it is located far from the movable pulley piece, the elastic spring force of the compression spring becomes too strong without being compressed extremely. It is sealed.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a partial cross-sectional view of a speed change pulley of the present invention. The speed change pulley 1 includes a fixed pulley piece 4 fixed to a shaft 2 by a fixing means 3 such as a bolt, a key or a spline, and a shaft facing the fixed pulley piece 4. 2 is provided with a movable pulley piece 5 which is movable at least in the longitudinal direction, and the movable pulley piece 5 is provided with thrust means for moving the movable pulley piece 5 on the back side thereof. Then, a V groove is formed by the fixed pulley piece 4 and the movable pulley piece 5, and the V groove is formed.
Belt B is wound around the groove.

As a thrust means for moving the movable pulley piece 5, first, a compression spring is provided between the movable pulley piece 5 and a slide type spring stopper 6 movably provided on a boss portion 5a of the movable pulley piece 5. 7 is contracted so that the movable pulley piece 5 can apply a thrust to the fixed pulley piece 4 side with respect to the slide type spring stopper 6.

A fixing piece 9 fixed to the shaft 2 by a fixing means 8 such as a bolt, a key or a spline is provided on the rear side of the sliding spring stopper 6, and the movable piece is moved from the fixing piece 9. Between the pulley piece 5 and the slide spring stopper 6, an extension portion 9a extending to a position beyond the movable pulley piece 5 is provided, and a tension spring 10 is provided between the extension portion 9a and the slide spring stopper 6.
Are arranged. Further, the slide type stopper 6 is in a semi-fixed state with respect to the fixed piece 9 by a slide mechanism using a guide bar 11 with a stopper.

Next, how the above-described speed change pulley 1 behaves while the belt is running will be described. As the drive-side pulley, a conventionally known speed change pulley is used in which the width of the pulley is wide when the rotation speed of the engine is low, and the width of the pulley becomes narrower as the rotation speed increases,
When the speed change pulley 1 of the present invention is used as a driven pulley, when the engine speed is low, the driving pulley has a wide width and the driven pulley has a narrow width.
In the driven pulley using the speed change pulley of the present invention, the movable pulley piece 5 is given the thrust by the compression spring 7 and is closest to the fixed pulley piece 4 side, and the slide type stopper 6 is pulled by the tension spring 10 and pulled out most. The movable pulley is close to one side.

In the case of the conventional speed change pulley 21 as shown in FIG. 2, the compression spring 27 is in the most extended state, and when the setting of the compression spring 27 is adjusted for medium and low speeds, the thrust force for pushing the movable pulley piece 25 is The thrust is almost the same as the required thrust, and in the speed change pulley 1 of the present invention, the tension spring 10 is stronger than the compression spring 7, and the slide spring stopper 6 shifts toward the movable pulley piece 5 side. Therefore, the speed change pulley 21 of the type shown in FIG.
The thrust force by the compression spring is almost the same as the required thrust force.

Further, when the engine rotation is high and stable, the pulley on the drive side has a narrow pulley width,
The driven side has a wider pulley width. At this time, in the speed change pulley 1 of the present invention used on the driven side, the belt B is located toward the bottom of the V groove of the pulley, and the compression spring 7 is in a compressed state. In the conventional speed change pulley 21, the compression spring 2
7 is the most contracted, and the thrust for pushing the movable pulley piece 25 is the strongest. On the other hand, in the speed change pulley 1 of the present invention, the force of the compression spring 7 becomes stronger than the force of the tension spring 10 due to the compression spring 7, and the slide spring stopper 6 is in the state of being closest to the fixed piece 9 side. 7 is extended to weaken the thrust applied to the movable pulley piece 5. In order to obtain such an action, the compression spring 7 is set to be weaker than the tension spring 10 in the medium and low speed range, and is set to be stronger than the tension spring 10 in the high speed range.

The amount of thrust that must be applied to the movable pulley piece of the speed change pulley is determined by the state of speed change and the amount of torque applied to the belt at that time. Even so, it may cause the belt and pulley to be worn or reduce the power transmission efficiency.

When it is desired to raise the engine speed from a low speed to a high speed, the torque increases and the load applied to the belt increases accordingly. However, in the conventional speed change pulley, when the compression spring is set for high speed, the spring moves the movable pulley piece. The thrust force that presses against is small and the belt and pulley may slip due to the loss of torque, which reduces the transmission efficiency and leads to wear of the belt and pulley. Furthermore, when the rotation becomes higher and acceleration is stopped and less torque is applied, the driven pulley has a wide pulley width and the spring force is the largest in the conventional speed change pulley, so the compression spring is set for medium and low speeds. Then, since excessive thrust was applied to the movable pulley piece, it could not be said that the transmission efficiency was good, and it also led to wear of the belt and pulley. However, in the pulley of the present invention, it can be said that the sliding type spring stopper moves to the fixed piece side to weaken the pressing force of the spring and to alleviate the application of excessive thrust to the movable pulley piece. FIG. 4 shows the relationship between the engine rotation speed and the thrust applied to the movable pulley piece at a predetermined rotation speed, and an appropriate thrust change 31 required by the movable pulley piece 31 is shown.
On the other hand, it can be seen that the thrust change 34 given to the movable pulley piece of the shift pulley of the present invention has less deviation in the high speed range than the thrust change 32 of the conventional shift pulley using the spring set for medium and low speeds.

[0017]

As described above, according to the present invention, a unique tension spring and a sliding spring stopper are used when the engine speed is high or low, and when the transmitted torque is large or small. Compare the effect of preventing wear of belts and pulleys and reduction of transmission efficiency by adjusting the pressing force of the compression springs so that the thrust applied to the movable pulley piece is as close to the appropriate value as possible. The present invention has been realized in a speed change pulley that has a simple mechanical structure, has few failures, and can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a speed change pulley according to the present invention.

FIG. 2 is a partial cross-sectional view of a conventional transmission pulley.

FIG. 3 is a graph showing necessary thrust applied to a movable pulley piece with respect to engine speed.

FIG. 4 is a graph showing a necessary thrust force applied to a movable pulley piece with respect to an engine speed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Speed change pulley 2 Shaft 3 Fixing means 4 Fixed pulley piece 5 Movable pulley piece 6 Sliding spring stopper 7 Compression spring 8 Fixing means 9 Fixing piece 9a Extension part 10 Tensile spring 11 Guide bar with stopper

Claims (1)

[Claims] 1. A speed change pulley comprising a fixed pulley piece that rotates integrally with a shaft and a movable pulley piece that is movable at least in the axial direction with respect to the shaft. A compression spring is interposed between the slide spring stopper and the movable pulley piece that are slidable with respect to the slide spring stopper and the movable pulley piece. A speed change pulley characterized in that a tension spring is interposed between an extension part extending up to and between a slide spring stopper.