JPH0219645Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a torsional damper for absorbing torsional vibration of a shaft, and more specifically, a torsional damper structure that extends the life of a torsional vibration absorbing means made of a rubber-like elastic material. This is what we present.

Torsional dampers are widely used, which are attached to the tip of the engine crankshaft to damp torsional vibrations generated in the crankshaft. Figure 1 shows an example of this type of torsional damper described in Japanese Utility Model Publication No. 42-15478, which includes a hub 1 fixed to the tip of the crankshaft and an annular body concentric with the hub 1. The hub 1 and the vibration ring 2 are made of a rubber-like elastic material.
The hub 1 and the vibration ring 2 are connected to each other by an elastic ring 3 attached to the hub 1, and the torsional vibration generated in the crankshaft is damped by the inertia of the vibration ring 2 and the elasticity of the elastic ring 3. Because the positions where the radially inward extensions of the mutually opposing surfaces intersect the central axis are offset from each other,
When the hub 1 and the vibration ring 2 rotate relative to each other, the amount of twist that occurs in the vibration ring 3 is
Since this varies depending on the radial position, a rubber portion with a large degree of torsion will break earlier than a rubber portion with a small degree of torsion, resulting in a problem that the service life will be shortened.

In view of the problems with the torsional damper according to the prior art described above, the present invention has been developed by configuring the hub and the vibration ring so that the extensions of the opposing surfaces of the hub and the vibration ring and the intersection points with the central axis coincide with each other. The purpose is to keep the amount of twist of the elastic ring uniform over all positions in the radial direction due to relative rotation, thereby preventing early breakage of the elastic ring.

Embodiments of the present invention will be described below based on the drawings. In the embodiment of FIG. 2, the elastic ring 3
The mutually opposing surfaces of the hub 1 and the vibrating ring 2 to which they are bonded are formed by surfaces 4 and 5 that extend approximately in the radial direction and surfaces 6 and 7 that exhibit an approximately truncated conical shape. The intersecting positions of the extension to and the central axis line are arranged to coincide with each other at positions indicated by symbols a and b in the figure. In order to inject the rubber-like elastic material forming the elastic ring 3 between the hub 1 and the vibration ring 2 and bond it to both members 1 and 2, injection holes 9 are arranged on the circumference and are arranged in the radial direction of the hub 1. It is pierced in the part.

In the torsional damper of the present invention, the radially opposing surfaces of the hub and the vibration ring ( Crimson angles (numbers 4 and 5 on Figure 2) and truncated cone-shaped opposing surfaces (numbers 6 and 7 on Figure 2)
If the angles of the elastic rings are set equal, the distance between corresponding points on each opposing surface, that is, the thickness of the elastic ring at the corresponding points,
Relative displacement in the circumferential direction between mutually corresponding points on each opposing surface when a relative rotational motion is generated between the hub and the vibration ring and torsional shear strain is applied to the elastic ring, that is, The total amount of shear strain applied to the elastic ring at the corresponding point is both the distance from the central axis of the corresponding point,
That is, since it is proportional to the value of the radius, the amount of shear strain of the elastic ring per unit length at any radial position is approximately constant regardless of the radial position. Since damage to the elastic ring due to localized shear strain observed in the damper is prevented, a stable vibration reduction function is maintained over a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a torsional damper according to the prior art, and FIG. 2 is a sectional view showing an embodiment of the torsional damper according to the present invention. DESCRIPTION OF SYMBOLS 1... Hub, 2... Vibration ring, 3... Elastic ring, 4, 5... Radial opposing surface, 6, 7... Frame-shaped opposing surface, 9... Injection hole.

Claims (1)

[Scope of utility model registration request] A hub 1 fixed to a shaft, a vibrating ring 2 formed concentrically with the hub 1, and an elastic ring 3 made of a rubber-like elastic material and connecting the hub 1 and the vibrating ring 2. The torsional damper is characterized in that the intersections of the extensions of the mutually opposing surfaces of the hub 1 and the vibration ring 2 and the central axis coincide with each other.