Patent ID: 8272282
Filing Date: 2012-09-25
Classification: F02N,Y10T

Abstract:
1. A starter motor comprising: an electric motor generating a rotational power; a planetary gear speed reduction device that reduces a rotation speed of the electric motor and outputs the reduced rotation speed; a shock absorbing device that limits a rotation of an internal gear in the planetary gear speed reduction device by a friction force, and absorbs a shock applied from an internal combustion engine by rotating the internal gear against the friction when the internal gear receives the shock caused by a load torque over a predetermined level, the shock absorbing device comprising: a frustoconical disk spring comprising: wherein the first end of the disk spring abuts the annular bottom flange of the cylindrical casing and the second end of the disk spring abuts a disk stack structure composed of the rotatable disks and the fixed disks stacked alternately; and wherein the upper part of the cylindrical casing is caulked toward the annular bottom flange to fix the disk stack structure against the second end of the disk spring, and the disk spring generates an elastic force against the disk stack structure; and wherein the inner diameter and outer diameter of the disk spring are selected so as to provide a spring constant that provides a stable spring load to the disk stack structure in the cylindrical case.