Patent ID: 7264549
Filing Date: 2007-09-04
Classification: F16D,F16J

Abstract:
1. A joint boot comprising a cylindrical large-diameter attachment part to be installed by external fitting to a mounting part of an outer casing, a small-diameter attachment part to be installed on a shaft, and a bellows part linking both, the large-diameter attachment part assuming on its outer peripheral surface a circular form in cross-section and being in its inner periphery area provided with a plurality of convex portions protruding radially inwardly so as to be distributed in the circumferential direction, the plural convex portions being constructed so that they can be externally fitted respectively in a plurality of recessed portions formed on the mounting part of the outer casing, wherein the large-diameter attachment part is formed in a separate body from the bellows part, and a fit cylinder part externally fitting on the large-diameter attachment part is extended at one extremity of the bellows part; each of the convex portions of the large-diameter attachment part comprises an inner wall portion radially inwardly jutting in a curved form and adapted to fit in each of the said recessed portions, an outer wall portion of an arc form constituting part of the outer peripheral surface of the large-diameter attachment part, a central strut wall connecting the inner wall portion and the outer wall portion in the circumferential middles of both and extending radially, and a pair of lateral strut walls linking the inner wall portion and the outer wall portion on both sides of the central strut wall, whereby four relief holes are provided on the convex portion so as to be juxtaposed in the circumferential direction; and which is characterized in that said relief holes include four first relief holes apertured on one edge face side of the large-diameter attachment part and juxtaposed in the circumferential direction, and four second relief holes apertured on the other edge face side and juxtaposed in the circumferential direction; there is provided a third strut wall supporting each of the inner wall portions by a partition wall dividing between the first relief holes and the second relief holes and extending in the circumferential direction.