Vehicle braking system with actively controlled caliper retractor

摘要

A vehicle braking system having a brake rotor (10) and brake pedal-actuated hydraulic piston (24) that actuates a brake caliper (22) to engage a friction brake (25a, 25b) with the rotor (10) and further having a brake caliper retractor mechanism (40) including an actuator (46) for actively controlling retraction of the caliper (22) relative to the rotor (10) to provide either a friction brake force versus pedal brake force curve where the friction brake initially contacts the rotor (10) such that braking force from the brake pedal P begins at zero pedal force or a friction brake force versus pedal brake force curve that is displaced relative thereto where the friction brake initially is positioned out of contact with the rotor (10) such that braking force from the brake pedal begins at a finite preselected pedal force greater than zero. In an electric or hybrid electric vehicle, the displaced friction brake force versus pedal brake force curve permits series regenerative braking by an electric drive of the vehicle. In a conventional vehicle powered only by an internal combustion engine, the displaced friction brake force versus pedal brake force curve avoids brake drag.