| 摘要 |
Provided is a speed reducer having a speed reduction gear mechanism configured so that rotational force inputted from a rotating input shaft (1) to a small-diameter bevel gear 2 will be transmitted to a large-diameter bevel gear (3) and the rotational force, the speed of which has been reduced, will be outputted from the large-diameter bevel gear (3) to an output shaft (4). A plate-like, fan-shaped permanent magnet (5) is provided affixed to a housing (6) so that the permanent magnet (5) will face the tooth surfaces (3a) of the rotating large-diameter bevel gear (3) and so that the permanent magnet (5) will not rotate about the axis of the large-diameter bevel gear (3). A lubricating magnetic fluid (L) is provided on a fan-shaped flat surface so as to be held thereon by magnetic force, the fan-shaped flat surface facing the gear surfaces (3a) of the permanent magnet (5). The permanent magnet (5) is disposed close to the gear surfaces (3a) of the large-diameter bevel gear (3) so that the lubricating magnetic fluid (L) will be in contact with the gear surfaces (3a). |
