Power Transfer Unit Disconnect

摘要

A power transfer unit in a front-wheel-drive based all-wheel-drive vehicle is operatively coupled to a transmission to continuously transfer rotational movement through a link shaft to a front wheel when the vehicle is in motion. The power transfer unit also selectively transfers rotational movement from the transmission to a rear driveline system. When the rear driveline system is connected to the transmission, lubricant contained within the housing is automatically distributed throughout the housing to lubricate components therein. When the rear driveline system is disconnected from the transmission, the lubricant contained within the housing is not distributed throughout the housing. Since rotation of the link shaft continues independently of the rear driveline system, bearings rotatably supporting the link shaft are isolated from the interior of the housing such that the bearings are lubricated by lubricant that is provided from outside the housing

主权项

1. A power transfer unit for a motor vehicle for transferring rotational movement from a transmission to a front wheel and selectively transferring rotational movement from the transmission to a rear driveline system, said power transfer unit comprising:
a transfer unit housing defining an interior; a link shaft extending from outside said transfer unit housing and substantially through said interior of said transfer unit housing, said link shaft including an outer surface, wherein said link shaft is continuously rotationally driven by the transmission when the vehicle is in motion and transfers rotational movement to the front wheel; a first input shaft extending from outside said transfer unit housing into said interior of said transfer unit housing, said first input shaft is coaxial with said link shaft and said link shaft extends axially through said first input shaft, said first input shaft including an inner surface and an outer surface, wherein said first input shaft is rotationally driven by the transmission; a second input shaft disposed within said interior of said transfer unit housing, said second input shaft is coaxial with said link shaft and said link shaft extends axially through said second input shaft, wherein said second input shaft is selectively coupled with said first input shaft to transfer rotational movement to the rear driveline system; at least one first seal disposed radially between said outer surface of said link shaft and said inner surface of said first input shaft to contain lubricant within said interior of said transfer unit housing; a first bearing support disposed radially between said outer surface of said first input shaft and said transfer unit housing for rotatably supporting said first input shaft; at least one second seal disposed radially between said outer surface of said first input shaft and said transfer unit housing to contain lubricant within said interior of said transfer unit housing, wherein said at least one second seal is positioned axially inboard of said first bearing support relative to said interior of said transfer unit housing; a second bearing support disposed radially between said outer surface of said link shaft and said transfer unit housing for rotatably supporting said link shaft; and at least one third seal disposed radially between said outer surface of said link shaft and said transfer unit housing to contain lubricant within said interior of said transfer unit housing, wherein said at least one third seal is positioned axially inboard of said second bearing support relative to said interior of said transfer unit housing.