BOOT FOR CONSTANT VELOCITY JOINT

摘要

PURPOSE: A boot of a constant velocity joint is provided to disperse stress and shearing force in tension and expansion by improving radial ratio of inner and outer rake portions of a last thread to minimize damage in contraction and expansion. CONSTITUTION: A radius(R0) of an outer rake portion of a last thread near a shaft combining portion(140) is about 38 to 61 percent as compared with a radius(R1) of an inner rake portion. A radial ratio(R0/R1) is about 41 to 50 percent when a rake angle(A) of the outer rake portion to a shaft is from 55 to 85 degrees. The radial ratio is from 38 to 45 percent when the rake angle is over 85 degrees. The radial ratio is from 50 to 61 percent when the rake angle is not formed by connecting outer and inner rake portions as a constant curved line. A total length(L) of a boot(100) before assembling is from 70 to 92 percent as compared with the total length of the boot after assembling. Thereby, durability is improved by having a regular ratio for the total length of the boot in expansion and refraction. A radial ratio of the last thread is improved to minimize damage in contraction and expansion.