| 摘要 |
PURPOSE:To prevent chattering phenomenon of a brush by transmitting part of heat generated at a slide unit of a brush to a heat sink unit exposed in an air duct through the heated part of a heat transfer device, thereby reducing the cooling air at the periphery of the brush. CONSTITUTION:An air duct 8a is disposed adjacent to a brush chamber 11, and airtightly partitioned from the chamber 11 via a partition 13a, to which a bore end 13b is approached to the outer periphery at the one axial end of a current collecting ring 3, the duct 8a and an incoming duct 10a are formed linearly, part of heated part 14a is buried part of a retainer 5, and a heat sink unit 14b is exposed in the duct 8a in a heat transfer device 14. The heat generated at the slide unit of a brush 4 is partly transmitted to the heat sink unit 14b, which is cooled by the cooling air in the duct 8a. |
