Silent chain

Abstract

In a silent chain, back surfaces of the link plates of a guide link row, a non-guide link row, or both, are formed with concave, arc-shaped portions having radii of curvature shorter than the minimum radius of curvature of the chain-contacting region of a chain guide shoe. The minimum height of the back surface of link plates having concave back portions is greater than the minimum distance between the inner tooth flanks and the nearest pin holes, and the minimum distance between the outer tooth flanks and the nearest pin holes.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a link plate according to the invention;

FIG. 2 is side elevational view of the link plate, illustrating the manner in which the link plate slides on a and a shoe of a chain guide;

FIG. 3 is a partially broken-away perspective view of a part of a silent chain according to the invention;

FIG. 4 is a side elevational view of a conventional link plate; and

FIG. 5 is a schematic front elevational view of the timing drive system of an automobile engine.

Claims

1. A silent chain comprising an alternating series of first and second rows of link plates, each row extending widthwise with respect to the length of the chain, in which: each link plate comprises a pair of teeth protruding in a first direction, a pair of pin holes for receiving connecting pins, and a back surface facing in a direction opposite to said first direction;each second row is displaced, in the direction of the length of the chain, from a pair of adjacent first rows in the series;the adjacent rows are interleaved and articulably interconnected by connecting pins; anda portion of the back surface of each of the link plates of at least the second rows of link plates have a concave arc-shaped portion.

2. A silent chain transmission comprising a silent chain according to claim 1, and a guide member having a shoe surface positioned for sliding engagement with the backs of at least the link plates of the second rows of link plates, in which said concave arc-shaped portions have a radius of curvature smaller than the smallest radius of curvature of said shoe surface.

3. A silent chain according to claim 1, in which: the teeth of each link plate having inner and outer flank surfaces, and are separated from each other by a tooth gap having a tooth gap bottom connecting the inner flank surfaces; andin each link plate having a concave, arc-shaped, portion, the shortest distance between the concave arc-shaped portion and the tooth gap bottom is greater than the shortest distance from the inner flank surface of each tooth and the closest pin hole and also greater than the shortest distance from the outer flank surface of each tooth and the closest pin hole.

4. A silent chain transmission comprising a silent chain according to claim 3, and a guide member having a shoe surface positioned for sliding engagement with the backs of at least the link plates of the second rows of link plates, in which said concave arc-shaped portions have a radius of curvature smaller than the smallest radius of curvature of said shoe surface.

5. A silent chain according to claim 1, in which one set of rows from the group consisting of the first and second rows is a set of guide rows, in which the link plates of each guide row are disposed between a pair of guide plates disposed on opposite sides of the chain, and in which the connecting pins of the chain are fixed in pin holes formed in the guide plates.

6. A silent chain transmission comprising a silent chain according to claim 5, and a guide member having a shoe surface positioned for sliding engagement with the backs of at least the link plates of the second rows of link plates, in which said concave arc-shaped portions have a radius of curvature smaller than the smallest radius of curvature of said shoe surface.

7. A silent chain according to claim 5, in which: the teeth of each link plate having inner and outer flank surfaces, and are separated from each other by a tooth gap having a tooth gap bottom connecting the inner flank surfaces; andin each link plate having a concave, arc-shaped, portion, the shortest distance between the concave arc-shaped portion and the tooth gap bottom is greater than the shortest distance from the inner flank surface of each tooth and the closest pin hole and also greater than the shortest distance from the outer flank surface of each tooth and the closest pin hole.

8. A silent chain transmission comprising a silent chain according to claim 7, and a guide member having a shoe surface positioned for sliding engagement with the backs of at least the link plates of the second rows of link plates, in which said concave arc-shaped portions have a radius of curvature smaller than the smallest radius of curvature of said shoe surface.