Valve system of braking device

摘要

A valve system of a braking device provided with a stroke simulator (64), which is located at the end of a liquid flow passage (41) connected to a connection passage (22d) for making a master cylinder (34) communicate with a wheel cylinder (32), and a third shut-off valve (62), that is a solenoid valve and performs opening and closing of a communication between the master cylinder (34) and the stroke simulator (64), wherein the third shut-off valve (62) is a normally closed valve; and the valve system opens the third shut-off valve (62) by applying a start-up voltage, thereafter keeps the open state of the third shut-off valve (62) by alternately applying a holding voltage lower than the start-up voltage and either the start-up voltage or an intermediate voltage, in order to prevent heat generated in the third shut-off valve (62) from becoming excessively high when keeping the open state of the valve (62).