JPS6114386B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a variable speed pulley device having a V-groove, and more particularly to a variable speed pulley device with a stable speed ratio, high reliability, and long life.

BACKGROUND OF THE INVENTION A speed change pulley device is provided for changing the rotation of a rotating shaft in a power transmission mechanism using a transmission belt. Such a variable speed pulley device generally includes a fixed rotating body fixed to a rotating shaft,
A movable rotary body that forms a V-groove facing the fixed rotary body and is attached to a rotary shaft so as to be able to approach and separate from the fixed rotary body, and a spring that urges the movable rotary body toward the fixed rotary body. For example, according to means such as adjusting the V-groove width of one of a pair of speed change pulleys or adjusting the distance between the rotating shafts, The transmission ratio is changed by changing the width of the V-groove and changing the radius of curvature of the transmission belt so that the tension of the belt and the biasing force of the spring device are balanced. For example, the special public official
This is the case with the pulley devices described in Japanese Patent No. 20294 and US Pat. No. 2,658,401.

Problems to be Solved by the Invention However, according to such a conventional speed change pulley device, when the tension of the transmission belt changes as the transmission torque changes in a constant speed ratio setting state, the transmission belt will move into the V groove. The disadvantage was that changing the width of the gear ratio made the gear ratio unstable. For example, when the transmitted torque fluctuates highly, the movable rotating body is moved against the biasing force of the spring device, and the radius of curvature of the transmission belt wrapped around the V-groove becomes smaller, changing the gear ratio. It's put away.

In addition, the movable rotating body is attached to the rotating shaft so that it can move in the axial direction using means such as splines or keys in order to be able to approach and leave the fixed rotating body. There was an inconvenience in that splines and keys were unavoidably worn due to relative micro-vibration and shock between the rotating shaft and the movable rotating body. Such wear causes backlash and movement obstruction of the movable rotating body, shortening the life of the speed change pulley device and reducing reliability.

The present invention has been made against the background of the above circumstances, and its purpose is to provide a speed change pulley device with a stable speed ratio, long life, and high reliability.

Means for Solving the Problems In order to achieve the above object, the present invention provides a rotary shaft and a rotary shaft which are provided oppositely on the rotary shaft to form a V-groove therebetween and which rotate together with the rotary shaft. The transmission belt includes a first rotating body and a second rotating body, and by changing the relative distance between the first rotating body and the second rotating body, the radius of curvature of the conductive belt at the portion wrapped around the V groove can be adjusted. In the variable speed pulley device, the first rotating body is provided with a central hole, and the rotating shaft is fitted into the central hole to enable the first rotating body to move in the axial direction and rotate around the axis. A first groove is formed in the inner circumferential surface of the central hole along a direction parallel to the axial direction or an inclined direction, and the first groove is formed in the outer circumferential surface of the rotating shaft opposite to the first groove.
A second groove that forms a column-shaped space together with the groove, and an end of the first groove on the second rotating body side and an end of the second groove on the first rotating body side. A compression coil spring is inserted between the circles and biases the first rotating body in a direction to narrow the V-groove and transmits rotational force between the first rotating body and the rotating shaft. The compression coil spring is disposed in a columnar space, and the compression coil spring is disposed in at least one of the first groove and the second groove due to a wedge effect due to relative rotation between the first rotating body and the rotating shaft. A wedge action surface is provided that elastically deforms the compression coil spring in the diametrical direction to increase the biasing force of the compression coil spring.

Operation and Effects of the Invention With this arrangement, when the first rotating body and the rotating shaft are relatively shifted around the axis as the transmitted torque fluctuates, the relative rotational force between them is transferred to the compression coil spring. , the compression coil spring is elastically deformed in the radial direction. Moreover, at least one of the first groove and the second groove that forms the columnar space in which the compression coil spring is disposed is provided with a wedge action surface, and the compression coil spring has a wedge effect. Since a force greater than the rotational force is applied to the compression coil spring, the diameter of the compression coil spring can be easily reduced.

When the diameter of the compression coil spring is reduced in this way, the compression coil spring tends to expand further in the longitudinal direction, so that the V-groove provided from the compression coil spring to the first rotating body is narrowed. The biasing force increases and the lateral pressure of the transmission belt is automatically increased. Therefore, even if the transmission torque fluctuates in the direction of increasing and the tension of the transmission belt increases, the lateral pressure of the transmission belt will automatically increase as the transmission torque fluctuates, and such transmission torque will increase. Regardless of the increase, the radius of curvature of the transmission belt sandwiched between the first rotating body and the second rotating body is maintained constant, and the speed ratio is stabilized.

Moreover, between the first rotating body and the rotating shaft,
Since the rotational force is transmitted through the compression coil spring that functions as a spline or key, relative slight vibrations and shocks between the first rotating body and the rotating shaft are absorbed by the elastic deformation of the compression coil spring. Ru. Therefore, compared to conventional speed change pulley devices that use splines or keys, operational problems such as backlash and twisting caused by wear of splines or keys are eliminated, resulting in a longer life and higher reliability. This results in a device that can be used in a variety of ways.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail based on the drawings.

In FIG. 1, a fixed rotating body 12 as a second rotating body and a movable rotating body 14 as a first rotating body are arranged facing each other on a rotating shaft 10. There is a V groove 1 between the rotating body 14 and
6 is formed. The fixed rotating body 12 includes a disk-shaped outer circumferential part 18 having a conical surface on one side and a bottomed cylindrical boss part 20, and the end face of the rotating shaft 10 inserted into the boss part 20 and the bottom part of the boss part 20. and are fastened with three bolts 22.

The movable rotating body 14 includes a disk-shaped outer circumferential portion 24 having a conical surface opposite to the conical surface of the outer circumferential portion 18 and a cylindrical boss portion 26. 10 is fitted, and the movable rotating body 14 is supported by the rotating shaft 10 such that it can freely move in the axial direction and rotate around the axis. Note that the boss portion 26 is fitted into the boss portion 20,
The outer circumferential surface of the boss portion 26 and the inner circumferential surface of the boss portion 20 are brought into sliding contact. Therefore, the fixed rotating body 12
is also supported by the boss portion 26, and the boss portion 2
6 is covered with the boss portion 20, and the rotating shaft 1
The sliding contact portion between 0 and the boss portion 26 is protected from dust and the like.

As shown in FIG. 2, the inner circumferential surface of the central hole 28 has three first
Concave grooves 30 are formed at equal angular intervals, and a cylindrical space is formed together with the first concave grooves 30 on the outer circumferential surface of the rotating shaft 10 in a portion facing the first concave grooves 30.
A second book groove 32 is formed. Note that the first groove 30 and the second groove 32 are formed with semicircular cross sections, but the radius of curvature of the semicircle of the second groove 32 is larger than the radius of curvature of the first groove 30. It has also been made smaller. In the cylindrical space formed by the first groove 30 and the second groove 32, the end of the first groove 30 on the fixed rotating body 12 side and the second groove 32 are arranged.
A compression coil spring 34 is interposed between the movable rotary body 14 side end portion of the movable rotary body 14 and biases the movable rotary body 14 toward the fixed rotary body 12 . The compression coil spring 34 has a radius that is approximately the same as the radius of curvature of the second groove 32, and approximately half of the inner circumferential side thereof is held within the second groove 32. The portion protruding from the first groove 32 is inscribed in a part of the inner circumferential surface of the first groove 30, which has a larger radius of curvature than the second groove 32 formed opposite to the second groove 32. Here, the compression coil spring 34 not only biases the movable rotary body 14, but also transmits rotational force between the movable rotary body 14 and the rotating shaft 10, as will be described later. It has the function of a key to guide the moving direction of the rotary shaft 10 and the movable rotary body 14, and also automatically adjusts the biasing force applied to the movable rotary body 14 in accordance with the transmitted torque, and suppresses slight vibrations and shocks between the rotary shaft 10 and the movable rotary body 14. It has an important function of absorption.

A ring-shaped cover 36 is fixed to the opening of the boss portion 26 on the opposite side of the fixed rotating body 12 with bolts 37 in order to protect the space between the central hole 28 and the rotating shaft 10 from dust and the like. Cover 36 and rotating shaft 1
The O-ring 38 that seals between the cover 36 and
It is provided on the inner peripheral surface of. In addition, the fixed rotating body 1
An O-ring 40 for sealing between the rotating shaft 10 and the boss portion 26 is also provided on the inner peripheral surface of the center hole 28 on the second side.

A V-belt 42 serving as a transmission belt is wound around the speed change pulley device configured as described above and other pulley devices provided on other rotating shafts (not shown) to transmit rotational force, and also to transmit rotational force to the other pulley devices (not shown). The V-groove width of the device may be changed, the distance between the rotating shaft 10 and another rotating shaft, or the V-belt 42 may be changed.
The speed is changed by changing the position of the tension roller.

The operation of this embodiment will be explained below.

When the V-groove width of another pulley device (not shown) is expanded, the distance between the rotating shaft 10 and another rotating shaft (not shown) is reduced, or the tension roller of the V-belt 42 is loosened, the V-belt 42
, the movable rotary body 14 moves toward the fixed rotary body 12 according to the biasing force of the compression coil spring 34, and the V-groove 16 is narrowed, and the V-belt in the portion hung on the V-groove 16 is narrowed. The radius of curvature of 42 is increased. That is, the movable rotating body 14 is moved to a position where the tension of the V-belt 42 and the biasing force of the compression coil spring 34 are balanced. FIG. 1 shows this situation. Therefore, when the rotating shaft 10 is a driven shaft, the rotational speed of the rotating shaft 10 is reduced, and when it is a driving shaft, the speed of another rotating shaft (not shown) is increased.

On the other hand, when the tension of the V-belt 42 is increased by performing the operation opposite to that described above, the movable rotary body 14 is moved against the biasing force of the compression coil spring 34, and the portion of the movable rotating body 14 that is hung in the V-groove 16 is moved. The radius of curvature of the V-belt 42 is reduced, and the speed is changed in the opposite direction. FIG. 3 shows this state.

In the above-described operation, the movable rotating body 14 is configured to rotate together with the rotating shaft 10 while being movable in the axial direction by the compression coil spring 34. Since rotational force is transmitted between the rotary shaft 10 and the movable rotary body 14, slight vibrations and shocks between the rotary shaft 10 and the movable rotary body 14 are absorbed by the elasticity of the compression coil spring 34, and the key , the movable rotating body 14 due to spline wear
This prevents any axial movement failure due to play in the rotational direction between the rotary shaft 10 and the rotating shaft 10, or twisting due to the play. For example, in a conventional speed change pulley device, if the same speed ratio is used for a certain period of time, the key or spline at a specific position will wear out, and when the speed ratio is subsequently changed, the movable rotating body is moved with rotational force applied. The movement of the movable rotor in the axial direction was unstable due to the wear, but according to this embodiment, this does not occur and the movable rotor can move extremely smoothly and reliably. It will be done.

In the speed change pulley device that performs the speed change operation as described above, when the transmission torque fluctuates while the rotational force is set to be transmitted at a constant speed ratio, the side pressure of the V-belt 42 changes depending on the fluctuation of the transmission torque. is automatically adjusted to stabilize the gear ratio. That is, for example, the rotating shaft 10
When the load suddenly increases, the torque transmitted between the movable rotary body 14 and the rotary shaft 10 increases, and the relative angle deviation between the movable rotary body 14 and the rotary shaft 10 increases. The diameter of the compression coil spring 34 is reduced based on the relative rotational force at the time. The two-dot chain line in FIG. 4 indicates this state.

Here, since the radius of curvature of the first groove 30 is much larger than the radius of the compression coil spring 34,
With the relative rotation between the movable rotary body 14 and the rotating shaft 10, the first groove 30 is inserted into the compression coil spring 3.
It has the same effect as a wedge with a tangential plane at the point of internal contact with 4. Therefore, a force much larger than the above relative rotational force is applied to the compression coil spring 34 due to the wedge effect due to the inner peripheral surface of the first groove 30, and the compression coil spring 34 is easily and sufficiently The diameter is reduced.

And like this, the compression coil spring 34
When the diameter of the compression coil spring 34 is reduced, the compression coil spring 34
increases the biasing force against the movable rotary body 14 as it tries to extend in the axial direction (longitudinal direction), so the movable rotary body 14 is pressed against the fixed rotary body 12 side according to the biasing force, and the side pressure of the contact portion of the V-belt 42 is reduced. is enhanced. As a result, even though the tension of the V-belt 42 increases due to fluctuations in the transmitted torque, the radius of curvature of the V-groove 16 is maintained, and the gear ratio is maintained stably. In addition, in this example,
The entire inner circumferential surface of the first groove 30 constitutes a wedge action surface that has a wedge action in both rotational directions, and since the compression coil spring 34 is disposed parallel to the axial direction, it can be used in either rotational direction. The above effect can also be obtained for.

In this way, according to this embodiment, as described above,
The side pressure of the V-belt 42 is automatically adjusted according to fluctuations in the transmitted torque, thereby stabilizing the speed ratio. Rotating body 1
This eliminates the problem of axial movement of No. 4 and improves reliability and durability, but it also has the following advantages.

In the conventional variable pulley device, it was necessary to provide an external push spring for urging the movable rotary body, whereas the compression coil spring 34 has the function of a key or spline and also presses the movable rotary body 14.
Since the pressure spring is biased, the conventional pressure spring and the space for providing it are not required, making the device compact and inexpensive. However, in addition to the compression coil spring 34, a compression spring similar to the conventional one may be appropriately provided externally. Further, in this embodiment, since the boss portion 26 of the movable rotary body 14 is configured to fit inside the fixed rotary body 12, there is an advantage that the dimension in the axial direction is reduced.

Further, the compression coil spring 34 is connected to the rotating shaft 10.
and the center hole 28 of the movable rotating body 14 at equal angular intervals, so that the rotating shaft 10 and the center hole 28
8 are automatically aligned by the radial elastic force of the compression coil spring 34 regardless of the fitting precision between them, making machining easier and eliminating radial play even during long-term use. It does not occur.

Furthermore, the elastic force of the compression coil spring 34 prevents play in the radial and rotational directions between the movable rotating body 14 and the rotating shaft 10, so wear caused by play and overheating during use are eliminated. . Therefore, extremely long life and high reliability can be achieved without the need for periodic oiling or disassembly and cleaning.

Next, another embodiment of the present invention will be described. In the following description, parts common to those in the above-mentioned embodiments are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 5, the first groove 30 and the second groove 32 are formed on the inner peripheral surface of the central hole 28 and the outer peripheral surface of the rotating shaft 10 along a direction inclined at a predetermined lead angle with respect to the axial direction. In the cylindrical space formed by the first groove 30 and the second groove 32, a compression coil spring 34 is disposed as in the previous embodiment.

Therefore, when the movable rotary body 14 receives a rotational force relative to the rotating shaft 10 in the direction of the arrow in the figure by the V-belt 42, the tilting action of the compression coil spring 34 having a key function causes As a result, the movable rotating body 14 receives a component force in the direction of approaching the fixed rotating body 12, and the side pressure of the V-belt 42 is further increased. That is, according to this embodiment, in addition to the effects of the above-described embodiments, the lateral pressure of the V-belt 42 applied in accordance with the transmitted torque is further increased due to the action of the lead angle (inclination angle) of the compression coil spring 34. Therefore, the gear ratio can be maintained more reliably.

Although the embodiment of the present invention has been described above based on the drawings, the present invention can also be applied to other aspects.

For example, the movable rotating body 14 and the fixed rotating body 1
2 constitutes the first rotating body and the second rotating body, but conversely, the second rotating body may be the movable rotating body 14 and the first rotating body may be the fixed rotating body 12.
Both the rotating body and the second rotating body are movable rotating bodies 14
It may also be configured to be movable, such as. In short, it is sufficient that at least one of the rotating bodies forming the V-groove 16 is configured as the movable rotating body 14.

The conduction belt may have not only the V-belt 42 but also other shapes such as a hexagonal cross section, and
A variable speed pulley device in which a plurality of transmission belts are connected in parallel may also be used.

Further, the cross-sectional shapes of the first groove 30 and the second groove 32 are approximately semicircular, and the radius of curvature thereof is larger than the radius of the compression coil spring 34 in the first groove 30; The second groove 32 may be larger, and the radius of curvature of both the first groove 30 and the second groove 32 may be larger than the radius of the compression coil spring 34. In this case, the inner circumferential surfaces of the first groove 30 and the second groove 32 together constitute a wedge action surface, and the wedge effect causes transmission between the rotating shaft 10 and the movable rotating body 14. The radial deformation of the compression coil spring 34 increases in response to the applied rotational force,
The side pressure automatically applied to the V-belt 42 becomes even larger in response to fluctuations in the transmitted torque. Furthermore, in the portions of the cross-sectional shapes of the first groove 30 and the second groove 32 that contact the compression coil spring 34,
A curved surface portion with a large radius of curvature or an inclined plane portion may be locally provided. The portion where the radius of curvature is increased and the inclined plane constitute a wedge action surface, which facilitates elastic deformation of the compression coil spring 34 in the diameter reduction direction.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing the configuration of an embodiment of the present invention. Figure 2 is - of Figure 1.
FIG. 3 and 4 are diagrams for explaining the operation of FIG. 1. FIG. 5 is a partially cutaway front view showing another embodiment of the present invention. 10: Rotating shaft, 12: Fixed rotating body (second rotating body), 14: Movable rotating body (first rotating body), 28: Central hole, 30: First groove (wedge action surface), 32: Second
Concave groove, 34: Compression coil spring, 42: V belt (conduction belt).

Claims (1)

[Claims] 1. A rotary shaft, and a first rotary body and a second rotary body that are provided oppositely on the rotary shaft to form a V groove therebetween and rotate together with the rotary shaft, The first
In a speed change pulley device that changes the radius of curvature of a portion of the transmission belt wrapped around the V-groove by changing the relative distance between a rotating body and a second rotating body, the first rotating body is provided with a central hole. At the same time, the rotating shaft is fitted into the central hole to enable the first rotary body to move in the axial direction and rotate around the axis, and the inner circumferential surface of the central hole is parallel to or inclined to the axial direction. A second groove is formed along the direction, and a cylindrical space is formed together with the first groove on the outer circumferential surface of the rotating shaft opposite to the first groove.
A groove is formed, and the V-groove is inserted between an end of the first groove on the second rotating body side and an end of the second groove on the first rotating body side. A compression coil spring is disposed in the cylindrical space to urge the first rotating body in a narrowing direction and to transmit rotational force between the first rotating body and the rotating shaft. The compression coil spring is elastically deformed in the diametrical direction by a wedge effect in accordance with the relative rotation between the first rotary body and the rotation shaft, and the compression coil is formed in at least one of the first concave groove and the second concave groove. A speed change pulley device characterized by being provided with a wedge action surface that increases the biasing force of a spring.