RELIEF VALVE STRUCTURE FOR FASTENING CLUTCH

摘要

PROBLEM TO BE SOLVED: To provide a relief valve structure for a fastening clutch to improve the degree of freedom of a layout and facilitate manufacture. SOLUTION: A relief hole 84 penetrating through from a wall surface, with which a return spring 32j is brought into contact, to a clutch cylinder chamber 32j for advance is formed in a clutch piston 32f for advance to press a multidisc clutch. A relief ball 86 is brought into contact with the opening part of the relief hole opened to the return spring side. The relief ball is pressed through the energizing force of a given return spring energizing toward the relief hole to close the relief hole. A given return spring 32 pressing the relief ball 86 is set to a spring constant to release closing of a relief hole 84 by the relief ball 86 when a pressure of working fluid in the clutch cylinder chamber 32j for advance attains a given value or more.