| 摘要 |
1,115,280. Cooling dynamo-electric machines. SIEMENS A.G. 21 Nov., 1966 [29 Nov., 1965], No. 52123/66. Heading H2A. [Also in Division F1] A miniature electric motor, e.g. for directly driving a dental tool, which is provided with a supply line and with at least one outlet aperture for the compressed air which is used for cooling the motor, is characterized in that the outlet aperture is provided in the cylindrical wall surface of the housing and is masked by porous material. As shown, a supply line 10 for compressed air is provided at the rear end of a motor housing 5. The air flows axially through the housing and axially into a disc 16 of sintered material which, in use, is threaded on to motor shaft 7 and secured by screws inserted through holes 21. The disc is thick enough to mask, completely, air outlet slots 13 in the housing 5. The air is constrained to change direction in the disc 16 and escape radially outwards through the slots 13. Air outlet noises are thus obviated. |
