VEHICLE BRAKE SYSTEM

摘要

In a brake-by-wire brake system which includes a motor actuated cylinder configured to produce a brake fluid pressure according to an operating stroke thereof and an electric motor for actuating the motor actuated cylinder, the control mode is normally based on a fluid pressure control, but is switched to a stroke control when the brake pedal is released for the purpose of quickly reducing the operating stroke of the motor actuated cylinder to an initial value. To avoid a sudden increase in the noises of the electric motor at the time of switching from the fluid pressure control to the stroke control, a limit circuit limits electric current supplied to the electric motor when the control mode is switched from the fluid pressure control to the stroke control.

主权项

1. A vehicle brake system, comprising
a power actuated fluid pressure source configured to produce a brake fluid pressure according to an operating stroke thereof; a power source for actuating the fluid pressure source; a brake unit actuated by the brake fluid pressure produced by the power actuated fluid pressure source; a stroke sensor for detecting the actual operating stroke of the power actuated fluid pressure source; a brake fluid pressure sensor for detecting an actual brake fluid pressure supplied to the brake unit; a brake pedal sensor for detecting a pedal stroke of the brake pedal; a target brake fluid pressure setting unit for setting a target brake fluid pressure according to the pedal stroke detected by the brake pedal sensor; a first control unit for setting a target operating stroke of the power actuated fluid pressure source for the given target brake fluid pressure, and controlling the power source for actuating the fluid pressure source according to a deviation of the actual operating stroke of the power actuated fluid pressure source from the target operating stroke thereof; a second control unit for controlling the power source for actuating the power actuated pressure source according to a deviation of the actual brake fluid pressure detected by the brake fluid pressure sensor from the target brake fluid pressure set by the target brake fluid pressure setting unit; and a control switch unit that selects the first control unit when the brake pedal is released and otherwise selects the second control unit.