BRUSH MONITORING DEVICE

PURPOSE: To accurately detect the wearing state of a brush by detecting the displacement of a spring receiver with a displacement detector, because, when the brush is worn, the spring receiver descends together with the brush and the slope on the side face of the spring receiver comes into contact and slides on a displacement gauge element, resulting in a shorter distance between the slope and displacement detector. CONSTITUTION: Vertical notches 1a are formed on the side faces of a brush holder 1 and spring supports 1b are formed by protruding the lower parts of the side faces outward from the holder 1. A spring receiver(SR) 3 is put on a brush 2 and the springs 4 at both ends of the leg sections 3a of the SR 3 are fitted to the spring supports 1b of the holder 1. Then a slope 3b is formed on one side face of the SR 3. A displacement detector 5 provided with a displacement detecting element 5a which is faced to the slope 3b and slides on the slope 3b while it is brought into contact with the slope 3b is attached to one of the spring support 1b. Wires 6 from the detector 5 are connected to a displacement gauge and the measured values of the displacement gauge are displaced in stages in accordance with the abrasion loss of the brush 2.