Split axle drive mechanism for part-time four-wheel drive vehicle

Claim 1

A split axle drive mechanism for a part-time four-wheel drive vehicle, comprising: a differential housing; a differential case rotatably mounted within said housing, said differential case being provided thereon with a ring gear for rotation about a first axis and therein with a pinion for rotation about a second axis orthogonal to said first axis and a pair of side gears in meshing engagement with said pinion for rotation about said first axis; a first axle shaft disposed along said first axis and connected to one of said side gears for rotation therewith; a second axle shaft disposed along said first axis and axially slidably connected to the other side gear for rotation therewith; a first output member disposed along said first axis to be connected to said first axle shaft; a second output member disposed along said first axis to be connected to said second axle shaft; a clutch mechanism including a spline wheel provided on an outer end of said first axle shaft, a matching spline wheel provided on an inner end of said first output member, and an internally splined clutch sleeve axially slidably mounted on said spline wheel of said first axle shaft and shiftable between a first position where it disengages from said matching spline wheel to disconnect said first axle shaft from said first output member and a second position where it couples said spline wheels to connect said first axle shaft to said first output member; a connecting rod axially movably disposed in said first and second axle shafts and having one end connected to said clutch sleeve and another end coupled within an outer end of said second axle shaft for axial movement therewith; coupling means including an internally splined sleeve integral with said second output member and a spline wheel provided on said second axle shaft to be brought into meshing engagement with said internally splined sleeve when said clutch sleeve is moved from the first position to the second position; and a shift mechanism including a slide rod axially slidably mounted within a portion of said differential housing and arranged in parallel with said first axle shaft, a shift fork fixed to said slide rod at one end thereof and coupled with said clutch sleeve at another end thereof; wherein said shift mechanism comprises a pneumatic actuator arranged to axially translate said slide rod, said pneumatic actuator including a housing assembly mounted on said differential housing coaxially with said slide rod, and a movable wall assembled within said housing assembly to internally subdivide said housing assembly into a pair of pressure chambers and being connected to said slide rod, and wherein said spline wheel of said second axle shaft is axially spaced from said internally splined sleeve of said second output member in a distance greater than a distance between said clutch sleeve and said matching spline wheel of said first output member when said clutch sleeve is positiond in the first position.