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Institute for Commercialization

Viscous actuated ball ramp clutch and improved housing therefor

Reference Number: N 04-03

Inventors: Leichliter, Wayne K.; Walton, Erlen B.

Owner: NISTAC

USPTO Link:5967276

Invention Summary

Accordingly, it is an object of the present invention to provide an improved differential device for use in a driveline of a vehicle, in which the device utilizes an improved housing, whereby final assembly involves a rollover of the housing for more economical assembly.

It is another object of the present invention to provide such an improved differential device which accomplishes the above-stated object and which includes a viscous coupling and a friction disc device, wherein the improved housing retains the viscous coupling and friction disc device against a reaction torque.

The above and other objects of the invention are accomplished by the provision of an improved differential device of the type including an input shaft adapted to receive input torque from a source of torque. The device also includes an output shaft adapted to provide driving torque to an output device, and a clutch pack including at least a first friction disc fixed to rotate with the input shaft and at least a second friction disc fixed to rotate with the output shaft. The device includes means operable to move the friction discs between a disengaged position and an engaged position comprising a cam ramp actuator including first and second ramp plates, and a plurality of cam members, each operably disposed between the first and second ramp plates, and in engagement with first and second ramp surfaces, respectively. The second ramp plate is disposed axially adjacent the friction discs and is operable to move the friction discs toward the engaged position, the means operable to move the friction discs further comprising a viscous coupling including an input coupling member fixed to rotate with the input shaft, and an output coupling member.

The improved differential device is characterized by a housing member defining, on its inside surface, at least one axially extending groove, extending at least a major portion of the axial extent of the housing. The first friction disc includes a retention portion extending radially therefrom and being disposed within the axially extending groove. The input coupling member of the viscous coupling includes a retention portion extending radially therefrom and being disposed within the axially extending groove. The housing member defines a shoulder surface extending radially outward adjacent the friction discs and the housing member further includes an endcap portion disposed axially adjacent the friction discs and in engagement with the shoulder surface. The housing member and the endcap portion include means providing relative axial retention therebetween. The housing member and the input coupling member include means providing relative axial retention therebetween.

In accordance with a more limited aspect of the invention, the improved differential device is characterized by the housing member comprising a unitary, stamped member having generally constant wall thickness.