Spiral cam clutch actuation system

A power transmission device for a motor vehicle includes a clutch for transferring torque between first and second shafts. A clutch actuation system includes a drive member and a cam member in cooperation with one another. The drive member is driven by an electric motor and includes first and second rollers rotatably mounted thereon. The cam member includes first and second circumferentially extending channels, each having a continually reducing radius. The first and second channels are separate from and overlap one another. The first roller is positioned within the first channel to engage the drive member and the cam member. The second roller is positioned within the second channel to engage the drive member and the cam member such that relative rotation between the drive member and the cam member translates the cam member along an axis of relative rotation to vary the force applied to the clutch.