Front wheel drive based power transfer unit (PTU) with hydraulically actuated disconnect

摘要

An arrangement of a vehicle is provided having normal transverse engine/transmission normal two-wheel drive operation which can be selectively placed into four-wheel drive operation wherein a pump which powers the coupling or uncoupling can be positioned downstream of a power takeoff unit without utilization of an electrically powered pump or transmission powered pump.

主权项

1. An arrangement for an automotive passenger vehicle having normal front-wheel drive and selective four-wheel drive mode, said arrangement comprising:
a transmission transversely mounted in said vehicle powered by a transversely-mounted vehicle engine; a front axle differential powered by said transmission having a casing extending transversely to a main axis of said vehicle, said front axle differential having front wheel shafts connecting with side gears for powering front wheel of said vehicle; a rear axle input shaft connected with said casing of said front axle differential, said rear axle input shaft encircling at least one of said front wheel shafts; a rear axle input gear rotatably mounted on said rear axle input shaft for powering a torsionally connected prop shaft; a rear axle differential torsionally connected with said prop shaft, said rear axle differential having a first state of operation differentially powering rear wheels and said rear axle differential having a second state where said rear wheels are non-driven and freewheel with respect to one another; a shift collar having a first position torsionally coupling said rear axle input shaft with said rear axle input gear and a second position decoupling said rear axle input gear with said rear axle input shaft; a hydraulic actuator for translating said shift collar; a hydraulic pump torsionally connected with said rear axle input gear for powering said hydraulic actuator; and an accumulator fluidly connected with said pump and said hydraulic actuator to supply pressurized hydraulic fluid to said actuator when said rear axle input gear is uncoupled from said rear axle input shaft.