| 摘要 |
PROBLEM TO BE SOLVED: To provide a driving force transmission device of a four wheel drive vehicle which creates a proper temperature environment of a viscous coupling and a differential mechanism and properly corrects changes in driving force characteristics of the viscous coupling and the differential mechanism which results from changes in the temperature environment.SOLUTION: A driving force transmission device of a four wheel drive vehicle includes a lubrication oil circulation passage (50) which introduces a lubrication oil guided to taper roller bearings (38, 39), which support a pinion shaft (36) of a rear differential (30), into an operation chamber (16) of a viscous coupling (10) by a discharge pressure resulting from rotations of the taper roller bearings (38, 39) and leads out the lubrication oil from the operation chamber (16) to a drain oil passage (56) in the pinion shaft (36) to return the lubrication oil to a casing (41). The structure allows the lubrication oil and a viscous fluid to conduct heat exchange in the operation chamber (16). |
