CENTER VALVE TYPE HYDRAULIC MASTER CYLINDER FOR VEHICLE

PROBLEM TO BE SOLVED: To mount a valve guide to a piston in a simple structure without much labor, to regulate displacement of a cup seal without increasing components, to prevent a parting line from occurring in a cup seal engaging section in a resin piston, to secure sealing property of the cup seal, and to secure compressive strength on the tip side of the piston. SOLUTION: The range from the cup seal engaging section 27a to the tip 27b of the piston 20 made of resin is defined as a cylindrical section 27. A cylindrical section 23b of the valve guide 23 is provided with a plurality of elastic claw pieces 23e for pressing the cylindrical section 27 in the axial direction of the piston, and the valve guide 23 is grappled by the elastic claw pieces 23e and adhered to the cylindrical section 27. One end 26a of a return spring 26 is adhered to the elastic claw pieces 23e, and the elastic claw pieces 23e are energized in the axial direction of the piston. A cup stopper 23c for regulating displacement of the cup seal 30 is formed integrally at the end on the opening side of the valve guide 23. Thus, the cylindrical section of the piston and the valve guide can be formed in a simple structure, and the valve guide can be mounted to the piston without much labor. The displacement of the cup seal can be regulated without increasing the number of part items. COPYRIGHT: (C)2004,JPO&NCIPI