Patent ID: 6520210
Filing Date: 2003-02-18
Classification: B21D,B23P,F16K,Y10T

Abstract:
A spool valve comprising:a plurality of small-diameter portions formed at predetermined spacings on a peripheral surface of a shaft, and pairs of annular ridges on peripheral surfaces of the small-diameter portions which have a larger diameter than an inner diameter of collars, the collars being closely fitted between the annular ridges to make valve bodies; wherein: the collars comprise an inner wall, an outer wall and at least one connection therebetween, the at least one connection is formed of the same material as that of the inner wall and outer wall, and connects the inner wall and the outer wall integrally to each other at a predetermined position on the inner wall and the outer wall, and an annular gap is provided between the inner wall and the outer wall.