Resin boots for constant velocity universal joint

Abstract

A resin boot for constant velocity universal joint, includes: a resin bellows including an approximately conical bellows-shaped portion with its inner hollow part, a small diameter end portion communicated with an inner space of the bellows-shaped portion and arranged at one end, and a large diameter side end portion communicated with the inner space of the bellows-shaped portion and arranged at the other end; a large thickness portion formed in an inner surface of a large diameter side end portion of the resin bellows in accordance with an injection molding, protruded in the vertical direction to the center of the large diameter side end portion and arranged in the circumferential direction at regular intervals; and a small thickness portion arranged between the large thickness portions and formed thinner in the diametrical direction compared with large thickness portion.

1 . A method of manufacturing a resin boot for a constant velocity universal joint including a resin bellows including an approximately conical bellows-shaped portion with an inner hollow space, a small diameter end portion communicated with an inner space of the bellows-shaped portion and arranged at one end thereof, and a large diameter side end portion communicated with the inner space of the bellows-shaped portion and arranged at the other end thereof, the large diameter side end portion having a plurality of protrusion portions protruded toward a central axis of the large diameter side end portion and arranged in a circumferential direction at approximately regular intervals, a different thickness portion including a plurality of large thickness portions, each corresponding to the plurality of protrusion portions, and a plurality of small thickness portions, each arranged between the adjacent plurality of large thickness portions and formed thinner in a diametrical direction than the large thickness portions, and formed such that the plurality of large thickness portions and the plurality of small thickness portions are continuously formed in the circumferential direction, and an integrally welded portion between an outer surface of the large diameter side end portion of the resin bellows and the different thickness portion, the method comprising:
 preparing the resin bellows;   forming a small thickness portion molding space and a large thickness portion molding space in the outer surface of the large diameter side end portion of the resin bellows to form the different thickness portion; and   injecting a molten material into the formed molding spaces, and welding and integrating the different thickness portion with the outer surface of the large diameter side end portion to form the integrally welded portion.   
     
     
         2 . The method according to  claim 1 ,
 wherein the molten material is injected into the small thickness portion molding space.   
     
     
         3 . The method according to  claim 2 ,
 wherein the molten material is injected into an approximate center in the circumferential direction of the small thickness portion molding space.