Four wheel drive power transmission system with clutch between central torque non balanced differential device and one wheel pair.

摘要

In this four wheel drive power transmission system for an automotive vehicle, there is provided a power distribution device which has a power input shaft driven from the vehicle engine and first and second power output shafts. The second power output shaft is rotationally coupled to either the front or the rear vehicle wheels. There is also provided a means for selectively either rotationally coupling or decoupling the first power output shaft to the other pair of vehicle wheels. A selectively controllable differential means is provided for selectively either driving both the first and second power output shafts individually from the power input shaft without providing any differential action between them, or driving these first and second power output shafts while providing differential action between them and while distributing a substantially larger proportion of input torque to one of them than to the other. Optionally, it may be the first rotational power output shaft to which the differential means, when providing differential action, distributes a substantially larger proportion of input torque. There may further be included a means for selectively either rotationally coupling or decoupling the second rotational power output shaft to its pair of wheels.