To make the buckling of a bellows part small when a dust cover is compressed.
This dust cover 26 includes a bellows part 28. In the bellows part 28, its inner diameter (trough diameter) and outer diameter (crest diameter) are kept constant respectively. Their pitch diameters are so set up as to be different from each other in such a way that they are formed out of a large pitch part 28a, and of a small pitch part 28b. The large pitch part 28a and the small pitch part 28b have a plurality of crest parts and trough parts respectively, in which their pitches are kept uniform respectively. The wall thickness of the small pitch part 28b is so formed as to be thinner than that of the large pitch part 28a. When the dust cover 26 is subjected to load in the direction of compression, the small pitch part small in pitch is compressed so as to be deformed first, and the large pitch part is compressed later on. The dust cover 26 as mentioned above is made by means of blow molding.
TANAKA NOBUHIDE
TIGERPOLY MFG INC
TIGERS POLYMER
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