JPS6235547B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a belt-type continuously variable transmission equipped with a clutch function, and more particularly to a technique for preventing noise when power transmission is interrupted and for smoothly starting power transmission.

Prior Art A drive shaft and a driven shaft are provided parallel to each other, and a pair of movable rotary body and fixed rotary body facing each other and forming a V groove are provided on the drive shaft and the driven shaft, respectively, and the movable A belt comprising a variable pulley whose effective diameter changes as the relative distance between a rotating body and a fixed rotating body changes, and a transmission belt that is wound between the variable pulleys and transmits rotation of the drive shaft to a driven shaft. In a continuously variable transmission, a protruding boss part is provided on the movable rotary body of the variable pulley on the drive side, and the V-groove width of the variable pulley is widened to support the inner circumferential surface of the transmission belt on the boss part, thereby increasing power. A belt-type continuously variable transmission is known which is provided with a clutch function that interrupts transmission. For example, belt-type continuously variable transmissions described in Japanese Patent Application Laid-Open No. 58-28037 and Japanese Patent Publication No. 58-28460 are examples of such belt-type continuously variable transmissions.

Problems to be Solved by the Invention However, in such a conventional belt type continuously variable transmission, when the inner circumferential surface of the transmission belt is supported on the outer circumferential surface of the boss portion of the movable rotary body in order to interrupt power transmission, There was an inconvenience that a relatively loud noise was generated due to friction. Furthermore, when power transmission is started by reducing the V-groove width of the variable pulley provided on the drive shaft, the transmission torque rises steeply and a sufficiently smooth connection cannot be obtained. , the minimum controllable rotational speed was high.

Means for Solving the Problems The present invention has been made against the background of the above-mentioned circumstances, and its gist is to provide a belt-type continuously variable transmission as described above. The movable rotating body of the variable pulley is rotatable relative to the drive shaft, and a boss portion extending toward the fixed rotating body is provided on the inner peripheral portion of the movable rotating body, and the boss portion is provided with a boss portion of the transmission belt. The second V-groove is formed, which has a groove bottom width smaller than the width of the inner circumferential surface and a larger opening angle than the V-groove.

Operation and Effects of the Invention With this structure, when the transmission belt is supported by the boss portion of the movable rotary body in order to interrupt power transmission, the inner corner of the transmission belt is connected to the second
Because it is supported in line contact with the inner wall surface of the V-groove,
Noise caused by friction is almost completely prevented.

Moreover, when the transmission belt is supported on the inner wall surface of the second V-groove, there is a gap between the side surface of the transmission belt and the inner wall surface of the V-groove formed between the pair of movable rotary bodies and the rotating rotary body. When power transmission is started by reducing the V-groove width of the variable pulley provided on the drive shaft, the fixed rotating body and one side surface of the transmission belt are always brought into surface contact, The contact surface pressure is gradually increased until the other side surface of the transmission belt and the remaining movable rotating body come into surface contact. Therefore, a smooth rise in the transmission torque is obtained, and the minimum controllable rotational speed is lowered.

Furthermore, since the boss portion is provided integrally with the movable rotary body, there is no need to provide a rotary body that can independently idle, and the belt type continuously variable transmission has a simple structure and is inexpensive.

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

In FIG. 1, a driving shaft 10 and a driven shaft 12 of a belt-type continuously variable transmission are rotatably provided in parallel with each other, and a variable pulley 14 with a variable effective diameter is attached to the driving shaft 10 and driven shaft 12. and 1
6 are provided respectively. The variable pulleys 14 and 16 are connected to the drive shaft 10 and the driven shaft 12.
fixed rotating bodies 18 and 20 each having a conical surface and having a conical surface opposite to the conical surface, and at least a driving shaft 10 and a driven shaft 12.
and movable rotary bodies 22 and 24 which are provided movably in the axial direction, respectively, and the width of the V groove formed between the fixed rotary bodies 18 and 20 and the movable rotary bodies 22 and 24 is variable. By doing so, the effective diameter, that is, the hanging diameter of the transmission belt 26 can be changed.

That is, in the drive shaft 10, the fixed rotary body 18 is made unrotatable around the axis by the key 28 and immovable in the axial direction by the retaining ring 30, and the movable rotary body 22 and the drive shaft 10 are By providing bearing metals 32 and 34 between them, the movable rotating body 22 can move in the axial direction with respect to the drive shaft 10 and can rotate relative to the shaft. A bearing case 38 fitted with the movable rotary body 22 via a bearing 36 is attached to a fixed position bracket 40, and a rotary operation member 42 is attached to the movable rotary body 22 via a bearing 36.
An adjustment member 44 that is moved in the axial direction in accordance with the operation of the rotary operation member 4 is abutted against the adjustment member 44.
The V-groove width of the variable pulley 14 can be changed according to the amount of operation of the variable pulley 14.

On the other hand, in the driven shaft 12, the fixed rotary body 20 is prevented from rotating around the shaft by the key 46 and is made immovable in the axial direction by the retaining ring 48, and the movable rotary body 24 is prevented from moving in the axial direction by the spring key 50. Therefore, it is mounted so as to be movable in the axial direction without being able to rotate around the axis. A compression coil spring 56 is inserted between the movable rotating body 24 and a spring receiver 54 which is made immovable in the axial direction by a C-shaped pin 52 on the driven shaft 12.
The movable rotating body 24 is biased in the direction in which the V-groove width becomes smaller. Thereby, the effective diameter of the variable pulley 16 is changed in accordance with the change in the effective diameter of the variable pulley 14, and the tension of the transmission belt 26 is appropriately maintained.

As shown in detail in FIG. 2, the variable pulley 14 is provided with a clutch mechanism. That is, a cylindrical boss portion 58 that extends toward the fixed rotary body 18 is provided on the inner circumferential portion of the movable rotary body 22 , and a boss portion 58 is provided on the inner circumferential portion of the rotating rotary body 18 in a predetermined manner. A fitting hole 60 is provided into which the fitting is fitted with a play of . The outer peripheral surface of the boss portion 58 has an opening angle α2 larger than the opening angle α1 of the V groove formed between the fixed rotating body 18 and the movable rotating body 22.
A second V-groove 62 is formed. The opening angle α1 is, for example, about 30 degrees, and the opening angle α
2 is, for example, about 90 degrees. And the above V groove 6
2 is a pair of inclined inner wall surfaces 64 and 66 and a groove bottom surface 6
The groove bottom surface 68 is smaller than the width of the inner circumferential surface of the transmission belt 26, and the outer circumference of one inner wall surface 64 is surrounded by a conical surface of the movable rotating body 22. They are connected at a certain angle.

The operation of this embodiment will be explained below.

Adjustment member 44 is adjusted as rotation operation member 42 is operated.
When the V-groove of the variable pulley 14 is pushed out toward the variable pulley 14 side, the V-groove width of the variable pulley 14 is reduced and its hanging diameter is increased. Therefore, the transmission belt 26 resists the biasing force of the compression coil spring 56 and pulls the variable pulley 1.
Since the diameter of the variable pulley 16 is reduced by being pushed into the V-groove of No. 6, the rotational speed of the driven shaft 12 of the continuously variable transmission is increased. On the contrary, the rotation operation member 42
When the V-groove width of the variable pulley 14 is increased as the variable pulley 14 is operated, the tension of the transmission belt 26 is reduced. The hanging diameter of 16 is expanded. As a result, the rotational speed of the driven shaft 12 of the continuously variable transmission is reduced.

When cutting off power transmission, the rotation operation member 4
By the operation 2, the width of the V groove of the variable pulley 14 is widened to the maximum. At this time, as shown in FIG. 3, the transmission belt 26 is received within the second V-groove 62 formed in the boss portion 58 of the movable rotating body 22.
In this state, a space is formed between the side surface and inner circumferential surface of the power transmission belt 26 and the fixed rotary body 18 and the movable rotary body 22, and the power transmission belt 26 is in line contact with the inner wall surfaces 64 and 66. Supported by Therefore, even if the transmission belt 26 and the movable rotating body 22 slide when power transmission is interrupted or when power transmission is started, almost no noise is generated because the contact area is small.

On the other hand, when starting power transmission, variable pulley 1
When the V-groove width of 4 is made smaller, first the fixed rotating body 1
8 is in surface contact with the side surface of the transmission belt 26, and in this state, the other side surface of the transmission belt 26 is in contact with the movable rotating body 22.
This surface contact continues until the transmission belt 26 is sandwiched between the fixed rotating body 18 and the movable rotating body 22.
In this process, the surface pressure between the fixed rotating body 18 and the side surface of the transmission belt 26 is gradually increased, so that
Transmitted torque rises gradually. Therefore,
Compared to conventional belt-type continuously variable transmissions, in which power transmission is started by bringing both sides of the transmission belt 26 into surface contact almost simultaneously, a smooth rise characteristic of the transmitted torque can be obtained, and the controllable minimum The rotation speed is lowered. According to experiments conducted by the present inventor, the lowest controllable rotational speed of the conventional continuously variable transmission was 200 rpm, whereas the continuously variable transmission of the present embodiment achieved a controllable minimum rotation speed of 50 rpm.
Therefore, for example, if the rotation ratio of a continuously variable transmission is 0.5
to 2.0, and when the drive shaft 10 is rotationally driven by an electric motor at 1800 rpm, the rotation of the driven shaft 12 can be controlled within the range of 50 rpm to 3600 rpm. FIG. 4 shows the rise characteristics of the amount of movement of the adjusting member 44 and the rotational speed of the driven shaft 12 under a constant load.
Line B in the figure shows the conventional case. Note that the broken line indicates an uncontrollable region where the rotational speed of the driven shaft 12 is unstable.

In addition, in the above-mentioned embodiment, the rotary operation member 4
Although the rotation ratio of the continuously variable transmission is controlled by operating 2, the rotary operation member 42 or an equivalent member may be driven using an actuator such as a motor or a hydraulic cylinder. The adjustment member 44 may be directly driven.

Although one embodiment of the present invention has been described above,
Other changes may be made to the present invention without departing from its spirit.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the configuration of an embodiment of the present invention. FIG. 2 is a partial sectional view showing the main part of FIG. 1. FIG. 3 is a diagram illustrating the operation of the embodiment of FIG. 1. FIG. 4 is a diagram showing the rise characteristic of the rotational speed of the driven shaft of the embodiment shown in FIG. 1 in comparison with the conventional one. 10: Drive shaft, 12: Driven shaft, 14, 16: Variable pulley, 18: Fixed rotating body, 22: Movable rotating body, 26: Transmission belt, 58: Boss portion, 62: Second V groove, 64, 66 : Inner wall surface, 68: Groove bottom surface.

Claims (1)

[Scope of Claims] 1. A drive shaft and a driven shaft provided parallel to each other, and a pair of fixed rotary body and movable rotary body facing each other and forming a V-groove, respectively. a variable pulley whose effective diameter changes as the relative distance between the fixed rotary body and the movable rotary body changes; and a variable pulley that is wound between the variable pulley and transmits the rotation of the drive shaft to the driven shaft. a transmission belt, the movable rotating body of the variable pulley is rotatable relative to the drive shaft, and a boss portion for receiving an inner circumferential surface of the transmission belt is arranged on an inner circumferential portion of the movable rotating body. In a belt-type continuously variable transmission of the type in which a belt is protruded toward the fixed rotating body, the boss portion has a groove bottom width smaller than the width dimension of the inner circumferential surface of the transmission belt and is wider than the V-groove. A belt-type continuously variable transmission characterized in that a second V-groove with a large opening angle is formed.