Power transfer device for four wheel drive

Claim 1

A power transfer device for two-wheel or four-wheel drive in combination with a power transmission having a transmission casing secured at one side thereof to a cylinder block of an internal combustion engine transversely placed on a vehicle body, an input shaft rotatably mounted within said transmission casing and arranged coaxially with a crankshaft of said engine, an output shaft rotatably mounted within said transmission casing in parallel with said input shaft, a changespeed gearing mounted on said input and output shafts, an output gear integral with said output shaft, and a differential gear unit rotatably mounted within said transmission casing and drivingly connected to said output gear, the power transfer device comprising: a transfer casing detachably secured at one side thereof to said transmission casing; a carrier member rotatably mounted within said transfer casing and arranged coaxially with said differential gear unit, said carrier member being formed with an internally splined bore; an output gearing assembled within said transfer casing and arranged to be driven by said carrier member; a first wheel axle driving connected at its inner end with said differential gear unit and extending outwardly through said transmission casing; a second wheel axle drivingly connected at its inner end with said differential gear unit and extending outwardly through said transfer casing; a hollow shaft arranged in surrounding relationship with said second wheel axle and axially slidably supported by said carrier member for rotation therewith, said hollow shaft being formed at one end portion thereof with an external spline in engagement with the internally splined bore of said carrier member and at the other end portion therof with an external spline selectively engageable with an internally splined bore in a differential case of said differential gear unit for selectively establishing two-wheel drive when the other end portion disengages from said differential gear unit, and four-wheel drive when the other end portion engages said differential gear unit.