Patent ID: 9566971
Date: 2017-02-14
CPC Classifications: B60T

Claim:
1. A hydraulic brake system comprising: a cylinder device provided in a vehicle and comprising (a) a housing, (b) at least one pressurizing piston fluid-tightly and slidably fitted in the housing, (c) at least one front chamber respectively provided in front of the at least one pressurizing piston, and (d) a rear-force control device operable by a supply of electric power and capable of controlling a rear force that is a driving force applied from a rear side, the rear-force control device being configured to apply the rear force to one pressurizing piston of the at least one pressurizing piston; a plurality of brake cylinders of a plurality of hydraulic brakes coupled to the at least one front chamber and provided respectively for a plurality of wheels of the vehicle, the plurality of brakes being configured to respectively restrain rotations of the plurality of wheels; a rear-force detection device configured to detect the rear force; and a liquid-leakage detection device comprising a difference-based detector configured to detect presence or absence of a liquid leakage from at least one line of at least one brake line comprising the at least one front chamber and at least one of the plurality of brake cylinders coupled to each of the at least one front chamber, the difference-based detector being configured to detect that there is a liquid leakage from the at least one line, when a state in which a subtraction value obtained by subtracting an actual rear force that is a value detected by the rear-force detection device from an estimated rear force that is an estimated value of the rear force is equal to or greater than a first malfunction determination threshold value had continued for a time equal to or greater than a first malfunction determination time, and thereafter the subtraction value has become equal to or less than a first return determination threshold value that is less than the first malfunction determination threshold value.