Patent ID: 6840043
Filing Date: 2005-01-11
Classification: B60T

Abstract:
1. A master cylinder comprising: a first cylinder portion and a second cylinder portion; a first piston portion that is slidably inserted into the first cylinder portion; a second piston portion that is slidably inserted into the second cylinder portion; a pressurizing chamber that is caused to expand and contract by the sliding of the first piston portion; a hydraulic chamber that is caused to expand and contract by the sliding of the second piston portion and communicates with a brake device via a hydraulic control unit; an open/close check portion that partitions the pressurizing chamber and the hydraulic chamber and permits flow of brake fluid only from the pressurizing chamber side to the hydraulic chamber side; a first flow path that communicates the pressurizing chamber and a reservoir; a control valve that includes a pilot chamber and switches the first flow path from a blocked state to a communicable state when pressure inside the pilot chamber reaches a predetermined fluid-release pressure; a second flow path that communicates the pilot chamber and the hydraulic chamber; and a restrictor disposed in the second flow path.