Differential lock actuator

A differential locking mechanism for a drive axle assembly having a pair of axle shafts comprising:

• a differential housing;
• a stationary member mounted to an axle structure and fixed relative to said differential housing, said stationary member having a fluid inlet;
• a rotating member supported by at least one bearing for rotation with respect to said stationary member and having a fluid outlet;
• a lock member selectively movable between an unlocked position and a locked position where said differential housing is locked for rotation with the axle shafts;
• and
• an actuator in fluid communication with said fluid outlet via a fluid passageway wherein a fluid flows through said fluid inlet to apply a force against said stationary member causing said rotating member to displace fluid into said fluid passageway via said fluid outlet to move said actuator from said unlocked position to said locked position.

A drive axle assembly comprising:

• an axle housing;
• a first axle shaft rotatably supported with respect to said axle housing for driving a first wheel;
• a second axle shaft rotatably supported with respect to said axle housing for driving a second wheel;
• a differential for controlling rotational speed and torque supplied to said first and second axle shafts;
• a locking mechanism selectively movable between an unlocked position where said first and second axle shafts can rotate at different speeds from each other and a locked position where said axle shafts are locked together for rotation at a common speed;
• and
• an actuator having a stationary portion and a rotating portion wherein a first volume of fluid applies an actuating force to said rotating member via said stationary member causing said rotating member to displace a second volume of fluid to move said locking mechanism from said unlocked position to said locked position.

A method for locking a differential in a drive axle assembly comprising the steps of:

• providing a stationary member having a fluid inlet, a rotating member having a fluid outlet, and a lock mechanism in fluid communication with the fluid outlet;
• applying a fluid force to the stationary member via the fluid inlet;
• actuating the rotating member with the stationary member;
• displacing fluid with the rotating member to a fluid passageway via the fluid outlet;
• applying a fluid force to lock the lock mechanism via the fluid passageway.