All wheel drive transfer case having two wheel overdrive

Abstract

A transfer case for a vehicle having a pair of front wheels and a pair of rear wheels and capable of all-wheel or two wheel drive has an input shaft connected to a carrier of a planetary gear differential having a ring gear connected to a first output shaft for driving a first pair of wheels and a sun gear connected to a second output shaft for driving a second pair of wheels. A clutch is provided on the planetary gear differential for selectively locking the first and second output shafts together for concurrent rotation when the planetary gear differential clutch is engaged, thereby providing all-wheel drive. A brake is provided for selectively preventing the second output shaft from rotating so that when the second output shaft brake is applied and the planetary gear differential clutch is disengaged, the first output shaft will rotate at an overdrive gear ratio relative to the rotational speed of the input shaft, thereby providing two-wheel drive at an overdrive gear ratio. Particularly, this overdrive ratio is in the range from about 0.3:1 to about 1.0:1.

Dependencies are inferred from the claim text.