US 7,069,805 B2 · Driving force transmission device

Abstract

A driving force transmission device includes a rim having a toothed outer periphery, with bottom lands being formed between respectively adjacent teeth and top lands being formed at teeth crests. Outer ribs are disposed at positions on an inner peripheral surface of the rim corresponding to the bottom lands, whereby there is neither variance in angle speed nor uneven rotation of a member driven by the transmission device. Moreover, the outer ribs are radially offset from inner ribs, whereby tensile forces generated between the outer and inner ribs and caused by material shrinkage cancel each other out and defective molding of teeth crests can be minimized. Accordingly, the radius of an imaginary circle formed by joining the top lands is uniform in a circumferential direction.

Claims10

Dependent claims

A driving force transmission device made of synthetic resin, comprising:

an annular rim including an outer periphery disposed with teeth;
a disc disposed on one edge of the rim;
an axis of rotation formed in a center of the disc and at an inner side of the rim;
ribs extending along lines which extend radially from the axis of rotation and said ribs connect to an inner peripheral surface of the rim;
and
a flange which extends outward from an edge of the rim that is opposite to the edge at which the disc is provided.

3 more elements

Dependencies are inferred from the claim text.

Driving force transmission device

Life of this patent

Driving force transmission device

Life of this patent

Abstract

Claims10