To detect a friction degree with high accuracy by detecting the friction degree of friction members on the basis of a rotating speed of a brake motor until the friction members abut to a rotary body in a motor-driven brake device for pressing the friction members to the rotary body rotating together with a wheel by using the brake motor as a motive power source.
At braking time, a piston 60 is displaced in the shaft direction by rotation of a motor shaft 50 caused by current-carrying to a brake motor 48, and a friction member 38a of a brake pad 38 is pressed to a friction surface 32a of a disc rotor 32. A friction member 40a of a brake pad 40 is pressed to a friction surface 32b of the rotor 32 by leftward displacement of the whole caliper 34, so that the rotor 32 is interposingly pressed between both friction members 38a, 40a to brake a wheel. In this case, when the friction members 38a, 40a are abraded, since a stroke of the piston 60 up to generating braking force, that is, a rotating speed of the brake motor 48 increases, an abrasion degree of the friction members 38a, 40a is detected on the basis of a rotating speed of the brake motor 48.
YOSHINO YASUNARI
AIZAWA HIROAKI
AISIN SEIKI