Abstract: A curved portion, with a curved cross section, is formed at the recess of the pad. The curved portion has a contact portion which contacts the leaf spring's tension surface, which faces the curved portion. The curved portion's thickness decreases from the contact portion to an end portion of the curved portion, thereby being spaced from the leaf spring's tension surface. In the pad, the height of the curved portion of the recess is set such that contact of the leaf spring's tension surface and the corner portion of the end portion of the curved portion can be avoided when the stroke length of the leaf spring's end portion is at maximum. Thus, the tension surface of the leaf spring is not worn by the corner portion of the end portion of the curved portion. As a result, breakage of the leaf spring caused by wear can be prevented.

Abstract: A curved portion 123, which has a curved cross section, is formed at the recess 121 of the pad 110. The curved portion 123 has a contact portion 123A which contacts the tension surface of the leaf spring 12, which is disposed so as to face the curved portion 123, in an initial condition. The curved portion 123 has a thickness which is reduced from the contact portion 123A to an end portion of the curved portion 123, thereby being spaced from the tension surface of the leaf spring 12. In the pad 110, the height of the curved portion 123 of the recess 121 is set such that contact of the tension surface of the leaf spring 12 and the corner portion of the end portion of the curved portion 123 can be avoided when the stroke length of the end portion of the leaf spring 12 is at maximum. Thus, the tension surface of the leaf spring 12 is not worn by the corner portion of the end portion of the curved portion 123. As a result, breakage of the leaf spring, which may be caused by wear, can be prevented.