Abstract: A lubricating mechanism includes: a rotational shaft; a casing housing a rear-end of the rotational shaft; a bearing between the rotational shaft and the casing; and an oil seal between the casing and one of the rotational shaft and a member rotatable with the rotational shaft in a space behind the bearing. The rotational shaft includes: a first oil passage extending from a front of the bearing towards the bearing; a second oil passage extending radially under the bearing, one side thereof communicating with the first oil passage and the other side thereof opening at a periphery of the rotational shaft; and a third oil passage extending between the periphery of the rotational shaft and an inner periphery of the bearing, one side thereof communicating with the other side of the second oil passage and the other side thereof communicating with the space.

Abstract: A vehicle includes a wheel speed sensor sensing a vehicle speed V, a 2WD/4WD switch operative to input an instruction to switch between a two-wheel driving state and a four-wheel driving state, a transfer and an actuator switching the two-wheel driving state and the four-wheel driving state, and an ECU driving the actuator. The ECU instructs the actuator to switch from the four-wheel driving state to the two-wheel driving state regardless of the switching instruction from the 2WD/4WD switch if the vehicle tows a trailer and runs in the four-wheel driving state when the vehicle speed exceeds a predetermined value. Consequently, it is possible to provide a four-wheel drive vehicle capable of running while towing an object and also avoiding an increase in the size of the peripheral parts of driving wheels.

Abstract: A vehicle includes a sensor sensing external temperature, a 2WD/4WD switch operated to input an instruction to switch a two-wheel drive state and a four-wheel drive state, a transfer switching mechanical power transfer for the two-wheel drive state and that for the four-wheel drive state, an actuator actuating the transfer, and an ECU controlling the actuator. The ECU determines from a value detected by the sensor a current supplied to the actuator. Preferably, the transfer includes a synchronizer mechanism driven by power generated by the actuator to transfer a drive shaft's rotation to a driven shaft and engage the shafts together when they achieve synchronous rotation.