| 摘要 |
In the present invention, a driving force transmission device (3, 5) is provided to the front end and back end of a propeller shaft (4) in a four-wheel-drive vehicle based on an FF system. Each driving force transmission device (3, 5) is provided with: a transfer mechanism (32, 52) comprising a hypoid gear; and a clutch mechanism (31, 51) that is connected to the hypoid ring gear (36, 56) of the transfer mechanism (32, 52). An electric motor (41) is provided to the propeller shaft (4), and when the electric motor (41) is rotated in the direction that causes the vehicle to move backwards while in a two-wheel-drive driving state, the hypoid ring gear (36) of the transfer mechanism (32) of the front-side driving force transmission device (3) moves along the center axis, and causes the clutch mechanism (31) to join together. By means of this joining, the engine torque is transmitted to the rear-side driving force transmission device (5) via the propeller shaft (4), and the hypoid ring gear (56) of the transfer mechanism (52) of the rear-side driving force transmission device (5) moves along the center axis, causing the clutch mechanism (51) to join together. As a result, the vehicle is switched to a four-wheel-drive driving state. |
