MASTER CYLINDER

• Main Author: TAIRA, KAZUHISA
• Format: Patent
• Language: English; French; German
• Published: 13.01.2010
• Subjects: ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; PERFORMING OPERATIONS; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OFVEHICLES; TRANSPORTING; VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES; VEHICLES IN GENERAL

A master cylinder according to the invention has a predetermined number of second axial grooves (24) formed on an outer peripheral surface of a tip portion of a secondary piston (9) at predetermined intervals apart in a circumferential direction. Second radial holes (25) are formed at the rear ends of some of the second axial grooves (24) in such a manner as to penetrate between the inner and outer peripheral surfaces of the piston (9). In an inoperative state, the rear ends of the second axial grooves (24) and the second radial holes (25) are all located to the rear of a seal point A of a second cup seal (17), and a second fluid supply chamber (21) is connected to a second hydraulic pressure chamber (15) via the second axial grooves (24) and the second radial holes (25). Furthermore, when the rear ends of the second axial grooves (24) and the second radial holes (25) are all moved in front of the seal point A, the second fluid supply chamber (21) is disconnected from the second hydraulic pressure chamber (15). Consequently, brake fluid supply performance is ensured and the processing of the piston is simplified as well as piston strength being ensured.