Patent ID: 8226176

Claim:
A brake system comprising: a master cylinder that generates brake fluid pressure by a braking operation of a driver; an electric motor-driven slave cylinder that generates brake fluid pressure according to an electrical signal which is based on the braking operation of the driver; a wheel cylinder that brakes a wheel by the brake fluid pressure of the master cylinder or the slave cylinder; the brake fluid pressure of the slave cylinder being transmitted to the wheel cylinder when the slave cylinder normally operates, and the brake fluid pressure of the master cylinder being transmitted to the wheel cylinder when the slave cylinder does not operate normally; and an opening and closing valve that opens and closes a fluid passage which connects the slave cylinder to the wheel cylinder, wherein when a problem occurs with the slave cylinder during braking such that the slave cylinder becomes inoperable, the opening and closing valve is closed for a predetermined time, thereby maintaining the brake fluid pressure applied to the wheel cylinder for said predetermined time.