Patent ID: 7585227

Claim:
A joint boot, comprising: a large-diameter attachment part to be attached to an outer peripheral contour of an outer housing, said outer peripheral contour having a plurality of recessed portions in the circumferential direction thereof, a small-diameter attachment part to be attached to a shaft, and a bellows part integrally joining said large-diameter attachment part and said small-diameter attachment part, wherein an external peripheral configuration of said large diameter part is a circular shape, wherein an internal peripheral configuration of said large diameter part bulges radially inwardly at a plurality of circumferential places thereof to form bulging portions; wherein at each of said bulging portions, the large-diameter attachment part comprises: an inner wall portion bulging radially inwardly in a curved form, an arc-like outer wall portion constituting part of an outer peripheral face of the large-diameter attachment part, a radially extending central strut wall linking the inner wall portion and the outer wall portion in peripheral middles of said inner wall portion and said outer wall portion, and lateral strut walls linking, on both sides of the central strut wall, the inner wall portion and the outer wall portion, the lateral strut walls slanting such that as the lateral strut walls extend radially outwards, the lateral strut walls approach the central strut wall, wherein said large diameter part further comprises longitudinal wall portions on a bellows part side of each of said bulging portions, so as to form a plurality of relief holes open in a direction away from said small-diameter part, and wherein a center line of a first lateral strut wall in its thickness direction, a center line of a second lateral strut wall in its thickness direction, and a center line of the central strut wall in its thickness direction intersect at an intersection point, and the intersection point is situated radially outwardly of an outer peripheral face of said large-diameter attachment part.