PURPOSE: To ensure efficient circulation of lubricating oil and to reduce the size and the weight of a device by forming an opening part, communicated with the hollow part on the small end side of a taper roller bearing, in a lubricating oil passage running from a pinion gear to an oil seal.
CONSTITUTION: When a drive pinion shaft 13 is rotated, taper roller bearings 14 and 15 are rotated, the first chamber 20 side is brought into a negative pressure state through the action of a pump with the aid of which liquid is delivered from the small end side toward the large end side, and lubricating oil in a lubricating oil passage 16 flows through a second opening 18 to the first chamber 20 side. A part of inflow lubricating oil lubricates the large taper roller bearing 14 and flows in a ring gear part. After the lubricating oil lubricates a ring gear 12 and a pinion gear 13a, it is returned through a first opening 17 to the lubricating oil passage 16. Meanwhile, after the rest of the lubricating oil flowing to the first chamber 20 lubricates the small taper roller bearing 15, it flows to a second chamber 22, and after it lubricates an oil seal 21, it is returned to the lubricating oil passage 16 again.
HORI HIROSHI
OKUBO HIROSHI
KOYO SHIKAGOROOHAIDO KK