JPH0452511Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention relates to a friction ring in a continuously variable transmission, and more specifically, to a continuously variable transmission in which a friction ring attached to the outer periphery of a friction disk is improved. This relates to friction wheels in

[Prior art]

Conventionally, a continuously variable transmission that has been used to change the running speed of the rubber track and rubber wheels of a small snowplow uses a driving source to control the drive shaft 1, as shown in FIGS. 2 and 3, for example. It consists of a drive rotary plate 2 rotated through the drive rotary plate 2, and a friction disk 4 which is pressed perpendicularly to the surface of the drive rotary plate 2 and has a rubber friction ring 3 attached to its outer periphery. By changing the radial contact position of the friction disk 4 with respect to the drive rotary plate 2, the rotational speed and rotation direction of the friction disk 4 can be changed, while the friction disk 4 can be separated from the drive rotary plate 2, or the drive rotary plate 2 can be moved away from the drive rotary plate 2. The rotation of the friction disk 4 can be stopped by holding the friction disk 4 at the center of rotation.

Therefore, in this type of continuously variable transmission, during power transmission, the rubber friction ring 3 attached to the outer periphery of the friction disk 4 is subjected to (a) compressive stress due to pressure contact with the driving rotary plate 2; (b) Tensile stress due to the transmission of rotational torque from the drive rotary plate 2; (c) Shear stress due to the difference between the inner and outer circumferences of the contact area with the drive rotary plate 2. These stresses act on the drive rotary plate 2 and Heat is generated at the contact area.

This phenomenon becomes more pronounced as the pressing force of the friction disk 4 against the drive rotary plate 2 is increased in order to obtain a large torque transmission force, and the life of the friction ring 3 is significantly shortened due to early cracks, etc. do. That is,
By increasing the pressure contact force, the deformation of the rubber increases and the heat generation of the rubber also increases. As heat is generated, the elastic modulus of the rubber also decreases, which further increases the deformation of the rubber, and as a result, cracks occur early.

Furthermore, repeated heat generation can lead to high-temperature oxidation due to the effect of oxygen in the air, accelerating deterioration of the rubber surface and similarly causing early cracking.

In particular, SBR, which is conventionally used for friction wheel 3,
(Styrene-butadiene rubber) JIS, A
Rubber, which has a hardness of about 70, decreases in elongation at break as it ages due to heat, so it has the disadvantage that it cannot withstand local deformation and often cracks.

As a means to solve the above problems, for example, as shown in FIG. 4, short fibers 5 are mixed inside the rubber material constituting the friction ring 3, and the short fibers 5
It has also been proposed to give orientation to (Japanese Unexamined Patent Publication No. 59-208264).

The friction ring 3 made by mixing these short fibers 5 is
Compared to the former, it exhibits superior abrasion characteristics without cracking under high loads, but due to the capillary action of the short fibers mixed in the rubber, the moisture absorption into the rubber is rate-limited, and the bonding interface X There was a problem in that the influence of moisture caused the adhesive force to decrease and the friction disc to rust, causing the friction ring to peel off.

[Purpose of invention]

This invention was devised by focusing on such conventional problems, and its purpose is to create a friction ring in a continuously variable transmission that is made by mixing short fibers inside the rubber material that constitutes the friction ring. By preventing the influence of moisture from acting on the adhesive interface between the friction disc and the friction ring, it effectively prevents a decrease in adhesive strength, rust generation, and peeling of the rubber material, and improves conductivity and durability. The present invention provides a friction wheel for a continuously variable transmission with improved performance.

[Structure of the idea]

In order to achieve the above object, this invention consists of a friction disk, an inner layer of rubber made of chloroprene rubber, and an outer layer of rubber made of the same material mixed with short fibers, which is mixed into the rubber. The gist of this is that the short fibers absorb moisture into the rubber through capillary action, thereby eliminating the influence of moisture on the adhesion interface.

[Example of idea]

An embodiment of this invention will be described below based on FIG. 1 of the accompanying drawings.

In the following description, the same components as those in the conventional example described above will be described with the same reference numerals.

FIG. 1 shows a continuously variable transmission mechanism in which this invention is implemented, in which reference numeral 4 indicates a metal friction disk, 3 indicates a friction ring made of soft rubber attached to the outer circumferential surface of the friction disk 4, and the friction ring 3 has a two-layer structure in which an outer rubber layer 7 made of the same material and mixed with short fibers 5 is laminated on the outer peripheral surface of a friction disk 4, with an inner rubber layer 9 made of chloroprene rubber coated thereon.

The inner rubber layer 6 and the outer rubber layer 7 are made of the same rubber material and are integrated when vulcanized and bonded. The thickness of the inner rubber layer 6 is 0.5 mm in order to prevent the influence of moisture on the adhesive interface X.
The above is preferable, and in order to maintain the performance of the friction ring 3, it is preferable that the elastic modulus of the inner layer rubber 6 and the outer layer rubber 7 be the same, so that the thickness of the inner layer rubber 6 is equal to the total rubber thickness. It is preferable to make it 30% or less of H.

Note that the molding direction is a method in which the outer peripheral surface of the friction disk 4 is coated with the inner layer rubber 6 in advance, and then an outer layer rubber 7 of the same material mixed with short fibers 5 is laminated to form a two-layer structure, or 6 and an outer rubber layer 7 made of the same material mixed with short fibers 5 may be integrally molded in advance, and this may be vulcanized and bonded to the outer peripheral surface of the friction disk 4.

In this invention, as described above, the outer layer rubber 7 is not attached directly to the outer peripheral surface of the friction disk 4, but is attached via the inner layer rubber 6 made of the same material, so that the short fibers 5 enter the rubber due to capillary action. There is no influence of moisture on the adhesive interface X caused by moisture absorption, and as a result, rusting of the friction disk 4 and peeling of the friction ring can be effectively prevented.

[Effect of idea]

This device is constructed by laminating a friction disk with an outer rubber layer made of the same material mixed with short fibers through an inner layer rubber made of chloroprene rubber, as described above, so that the adhesive boundary between the friction disk and the friction ring is This prevents the influence of moisture from acting on the surface, resulting in a decrease in the adhesion between the friction ring and the friction disc, rust on the friction disc, and separation between the friction disc and the friction ring. It has the effect of being able to effectively prevent this and significantly improve transmission performance and durability.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway cross-sectional view of a friction wheel implementing this invention, Figs. 2 to 4 show a conventional continuously variable transmission, and Fig. 2 is a schematic configuration diagram of the continuously variable transmission. 3 is an enlarged front view with a portion of the friction ring shown in FIG. 2 cut away, and FIG. 4 is a sectional view of the friction ring of another conventional example with a portion cut away. 3...Friction ring, 4...Friction disk, 5...Short fiber, 6...Inner layer rubber, 7...Outer layer rubber.

Claims (1)

[Scope of utility model registration request] In a friction ring in a continuously variable transmission consisting of a drive rotary plate rotated by a drive source and a friction disk that is pressed orthogonally to the surface of the drive rotary plate and has a friction ring attached to its outer periphery, A friction ring for a continuously variable transmission, characterized in that it is constructed by laminating an inner rubber layer made of chloroprene rubber and an outer rubber layer made of the same material mixed with short fibers.