To provide a reduction gear which can efficiently eject contamination from an oil pooling groove arranged in an upper section of bearing housing.
A turning reduction gear 22 is equipped with a reduction mechanism 32 in which an oil 31 for lubrication is filled, and a bearing housing 33 arranged in a lower section of this reduction mechanism 32. An output shaft 36 transmitting rotation to a driving gear 23 is rotatably held by bearings 34, 35 within the bearing housing 33. An oil pooling groove 61 profiled in concave which has a gradually changing difference in height over a whole circumference of the upper section of the bearing housing 33 is arranged in an inner circumferential side of a taper section 52 of the bearing housing 33. The oil pooling groove 61 is formed by casting so that the height may be gradually changed spirally. A drain hole 63 is opened from the lowest location 62 in this oil pooling groove 61 to the outside, and the drain hole 63 is closed by a drain plug 64.
COPYRIGHT: (C)2011,JPO&INPIT
KUDO SOJI
NAITO TAKAYUKI
SHIOKAWA TAKAYUKI
Satoshi Kabazawa
Tetsuya Yamada
Naozumi Ono
Sachiko Okunuki