| 摘要 |
PURPOSE:To prevent a foreign material from entering into a motor body by forming a rear cover for containing a slip ring, a brush holder at the outer portion at opposite side to a pulley side of a frame for surrounding a rotor, a fan and a stator, and providing an air exit. CONSTITUTION:A slip ring 6, a brush 4, a rectifier and a brush holder 2 are disposed at the opposite side to a pulley of a frame for surrounding a stator, a rotor and a cooling fan (omitted in the drawings), and covered with a rear cover (not shown). A slip ring box 1A provided with a brush inserting window 1e around the ring 6 is provided integrally with the frame at the outside of the frame, and an elastic material is provided to seal between the upper end face of the box 1A and the lower outer periphery of the holder 2. An air intake port 1a, a vent passage 1b, an outlet 1d, and an exhaust port 1c are provided at the box 1A, the air intaken from the rear cover is initially flowed upward to prevent a foreign material from entering. In this manner, dust can be prevented by a simple structure, thereby efficiently cooling the device. |
