JPH0633809B2 - Torque cam device - Google Patents

Description

The present invention relates to a torque cam device for generating a thrust force according to a transmission torque, particularly a cam roller. The present invention relates to a cam roller floating type torque cam device which is not supported by any of the output members.

Conventional technology and its problems Conventionally, there are roughly two types of torque cam devices,
One is a cam roller supporting type torque cam device in which a cam roller is supported by one of an input member and an output member as described in JP-A-58-142060, and the other is, for example, JP-A-59-175666. A cam roller floating type torque cam device in which a cam roller is arranged in a floating state between the input and output members facing each other as described in Japanese Patent Laid-Open Publication No. 2003-242242. In particular, the cam roller floating type torque cam device is suitable for a large torque that receives a large surface pressure because the cam roller is sandwiched between the opposed cam surfaces.

In the above cam roller floating type torque cam device, the transmission torque applied to the input member is transmitted to the cam roller as a thrust in the axial direction via the cam surface, and the thrust is further transmitted from the cam roller to the output member via the cam surface. When a positive direction drive torque is applied, the cam roller rolls while maintaining constant contact with the cam surface, but when a sudden reverse drive torque is applied, such as during engine braking, the cam roller momentarily separates from the cam surface. Next, when the positive drive torque is applied again, the contact position between the input side cam surface and the cam roller and the contact position between the output side cam surface and the cam roller may be inconsistent. A normal thrust cannot be generated because slippage occurs between the cam surface and one of the cam surfaces. This means that, for example, if the torque cam device is V
When it is used in a belt type continuously variable transmission, slippage between the belt and the pulley is caused.

OBJECT OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to keep the cam roller of the input side cam surface and the output side cam surface even if the cam roller separates from the cam surface when the reverse drive tokule is applied. It is an object of the present invention to provide a torque cam device which can be held at an intermediate position and can prevent slippage between a cam roller and a cam surface.

To achieve the above object, the present invention provides an input / output member arranged on the same axis so as to be rotatable relative to each other in the axial direction and the rotational direction, and a cam provided on the facing surface of the input / output member. In a torque cam device that includes a cam surface and a cam roller that is rotatably arranged between the cam surfaces, and applies a thrust force corresponding to a transmission torque from the input member to the output member, a retainer that rotatably supports the cam roller between the input and output members. And one end of the retainer is supported by the output member, and the retainer is supported by two compression springs and elastically supported at the center position of the cam surface on the output side.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawings show an example in which the torque cam device according to the present invention is applied to a drive side pulley of a V-belt type continuously variable transmission, and a rubber or resin V is provided on an input shaft 1 connected to an engine.
A fixed sheave 3 and a movable sheave 4 that sandwich the belt 2 are supported. The fixed sheave 3 is spline-coupled to the input shaft 1, and the movable sheave 4 that is an output member of the torque cam device is supported so as to be movable in the axial direction and the rotational direction with respect to the input shaft 1. An oil seal 5 is arranged between the inner diameter of the movable sheave 4 and the input shaft 1 to prevent the lubricating oil from leaking to the belt transfer surface.

A torque cam flange 6 which is an input member of the torque cam device is spline-engaged with the shaft end portion of the input shaft 1,
It is tightened and fixed by the nut 7. A cylinder 6a protruding toward the movable sheave 4 is integrally formed on the torque cam flange 6, and an annular first cam member 8 is formed by an outer peripheral projection 8a in a vertical groove 6b formed on the inner circumference of the cylinder 6a. Are engaged in the direction. On the other hand, the movable sheave 4 is provided with a cylinder 4a projecting on the outside of the cylinder 6a of the torque cam flange 6 via an oil seal 9, and the vertical groove 4b formed on the inner periphery of the inner part of the cylinder 4a has a vertical groove 4b. A second cam member 10 having the same shape as the first cam member 8 is axially engaged by the outer peripheral projection 10a.

The first cam member 8 and the second cam member 10 face each other with a third
Three cam surfaces 8b and 10b having the shape shown in the figure are formed, and a cam roller 11 is rotatably arranged between the cam surfaces 8b and 10b. The shaft portion 11a provided on the inner peripheral side of the cam roller 11 is rotatably supported by a cylindrical retainer 12 arranged between the movable sheave 4 and the torque cam flange 6, whereby each cam roller 11 is rotated by 120 °. Held at intervals. On the outer peripheral side of the cam roller 11, a spherical surface 11b having the same curvature as the inner peripheral surface of the cylinder 6a is formed.
b is contacted and supported by the inner peripheral surface of the cylinder 6a. Collars 12a and 12b are intermittently formed on both outer peripheral edges of the cage 12, and stepped portions 8c and 10c are formed on the inner surfaces of the tops of the cam members 8 and 10 corresponding thereto. . Step 8c, 1 above
When the cam roller 11 reaches the vicinity of the tops of the cam surfaces 8b and 10b, 0c stops the inside of the flange portions 12a and 12b to prevent the cam roller 11 from passing over the cam surfaces 8b and 10b.

Inside the retainer 12, two cylindrical retainers 13 and 14 are arranged so as to be rotatable relative to each other with a thrust needle 15 in between, and these retainers 13 and 14 are retained by their outer diameter portions 13a and 14a. Holds both sides of 12 and regulates axial movement. Inner diameter part 13b of retainer 13 and torque cam flange 6
A compression spring 16 is arranged between the and, and a compression spring 17 having the same specifications as the compression spring 16 is also arranged between the inner diameter portion 14b of the retainer 14 and the movable sheave 4.
The retainers 13 and 14 are held at the center positions of the torque cam flange 6 and the movable sheave 4 by these compression springs 16 and 17. That is, the retainer 12 supporting the cam roller 11 is elastically held at the center position of the cam surface 8b, 10b regardless of the change of the gear ratio and the contact between the cam roller 11 and the cam surface 8b, 10b. The compression springs 16 and 17 have a function of holding the cage 12 at the center positions of the cam surfaces 8b and 10b,
It also has a function of giving an initial thrust to the movable sheave 4 so that the V-belt 2 does not loosen even when the pulley is stopped.

Description of Operation First, since no transmission torque acts on the torque cam flange 6 when the input shaft 1 is stopped, the cam roller is
11 is located on the bottom of the cam surface 8b, 10b, and the compression spring 16,1
Only the spring force of 7 is applied to the movable sheave 4 as the initial thrust.

Now, when a positive direction driving torque is applied to the input shaft 1, the movable sheave 4 lags behind the fixed sheave 3,
Due to this delay, the second cam member 10 that rotates integrally with the movable sheave 4 lags behind the first cam member 8 that rotates integrally with the fixed sheave 3 in the direction opposite to the arrow A direction in FIG. As a result, as shown in FIG. 3, the cam roller 11 rolls on the cam surfaces 8b and 10b to press the movable sheave 4 toward the fixed sheave 3 side, and this pressing force causes the belt tension corresponding to the transmission torque to the V-belt 2. Is given, the torque is transmitted to the V-belt 2 between the sheaves 3 and 4 without slipping.

As described above, when the engine brake is suddenly applied with the positive drive torque applied, the second cam member 10 on the output side precedes the first cam member 8 on the input side at that moment, as shown in FIG. Then, the cam roller 11 separates from the cam surfaces 8b and 10b.
However, since the retainer 12 supporting the cam roller 11 is always held at the center position of the cam surfaces 8b and 10b by the compression springs 16 and 17, when the positive drive torque is applied again,
As shown in the figure, the cam roller 11 always contacts the same corresponding positions of the cam surfaces 8b and 10b, and there is no discrepancy. Therefore, even if the torque fluctuates, slippage does not occur between the cam roller 11 and the cam surfaces 8b, 10b, and a thrust force corresponding to the transmission torque can always be generated,
Eventually, slippage between the sheaves 3, 4 and the V belt 2 can be prevented.

In the above embodiment, the retainer 12 is elastically supported by the compression springs 16 and 17 via the retainers 13 and 14 and the thrust needle 15, but the retainers 13 and 14 are the thrust needle 1
The retainer 12 may be directly elastically supported by the compression springs 16 and 17 by omitting the number 5.

Further, in the above embodiment, the cam surfaces 8b and 10b have a sawtooth wave shape having a slope on only one side, but they may have a mountain shape having slopes on both sides. Further, the cam surface is not limited to being formed on the cam members 8 and 10 separate from the input / output members 6 and 4, but the cam surface may be integrally formed on the input / output members.

EFFECTS OF THE INVENTION As is apparent from the above description, according to the present invention, the retainer supporting the cam roller is held at the center position of both cam surfaces by the compression spring. Even if they are separated from each other, the contact is made at the original position when the positive drive torque is applied next time, so that there is no possibility that the contact positions of the cam roller and the input side cam surface and the output side cam surface are different from each other. Therefore, there is no risk of the cam roller slipping on the cam surface due to torque fluctuation, and a stable thrust can always be generated.

[Brief description of drawings]

FIG. 1 is a sectional view of an example in which a torque cam device according to the present invention is applied to a V-belt type continuously variable transmission, and FIGS. 2 and 3 are sectional views taken along line II-II and line III-III in FIG. FIG. 4 and FIG. 4 are operation diagrams when a reverse driving torque is applied. 1 ... Input shaft, 4 ... Movable sheave (output member), 6 ...
Torque cam flange (input member), 8, 10 ... Cam member, 8b, 10b ... Cam surface, 11 ... Cam roller, 12 ... Cage, 13,14 ... Retainer, 16,17 ... Compression spring.

Claims (1)

[Claims] Claim: What is claimed is: 1. An input / output member arranged on the same axis line so as to be relatively rotatable in an axial direction and a rotational direction, a cam surface provided on an opposing surface of the input / output member, and freely rollable between the cam surfaces. In a torque cam device that includes a cam roller arranged in the input member and applies a thrust force corresponding to the transmission torque from the input member to the output member, a retainer for rotatably supporting the cam roller is disposed between the input and output members, and the retainer has one end A torque cam device, characterized in that two compression springs respectively supported by the input and output members are elastically supported at the center position of the input-side cam surface.