Patent ID: 7753380

Claim:
A boot for a constant-velocity universal joint, the boot comprising: a minor-diameter cylindrical portion having opposite ends and inside and outside diameters, and being retained to a shaft; a major-diameter cylindrical portion having opposite ends and inside and outside diameters that are larger than the inside and outside diameters of the minor-diameter cylindrical portion, and being disposed separately away from the minor-diameter cylindrical portion and coaxially therewith; a bellows connecting the minor-diameter cylindrical portion with the major-diameter cylindrical portion integrally, and having opposite ends and an overall outer configuration being formed in a truncated cone shape; the bellows comprising a plurality of crests and roots, including a first crest, a first root, a second crest, and a second root, disposed alternately in this order from one of the opposite ends that faces the minor-diameter cylindrical portion to the other one of the opposite ends that faces the major-diameter cylindrical portion; and the bellows further comprising a rising planar wall connecting one of the opposite ends of the minor-diameter cylindrical portion that faces the bellows with a top of the first crest in the bellows in an axial cross section, and exhibiting a rising angle falling in a range of from 25 to 35 degrees to an imaginary central line of the boot or that of the shaft; and the bellows further comprising a first bellows-making wall, which connects the top of the first crest with a bottom of the first root, and which exhibits an angle falling in a range of from 85 to 95 degrees to an imaginary central line of the boot or that of the shaft under such a fixed condition that the minor-diameter cylindrical portion is retained to the shaft and the major-diameter cylindrical portion is retained to a mating member.