| 摘要 |
The especially planetary gear (1) has a housing (2) containing at least one air-vent (4) through its wall (2,3). The vent contains a cap-shaped membrane (5) deformable under differences in pressure and fixed to a rim (6). One side of the membrane is connected to the interior of the housing; the other side is connected to the external environment. The membrane has a side wall (10) over at least part or the whole of the holder-rim, and has a base (11) into which the side wall leads. At least part of the side wall together with the base is movable and invertable. |
