Patent 7287440 was granted and assigned to Kayaba Industry on October, 2007 by the United States Patent and Trademark Office.
A magnetism generation portion 4 is provided at a first shaft 2, and a first magnetic yoke 7 and a second magnetic yoke 8 bent in L shape are provided at a second shaft 3 so that a magnetic flux generated at the magnetism generation portion 4 can be detected on the outer circumference side of the second shaft 3, and a magnetism detecting device for detecting the magnetic flux can be provided on the outer circumference side of the second shaft.