The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 27, 2011
Filed:
May. 13, 2008
Russell T. Capito, Clarkston, MI (US);
Charles G. Stuart, Rochester Hills, MI (US);
Paul J. Valente, Berkley, MI (US);
Russell T. Capito, Clarkston, MI (US);
Charles G. Stuart, Rochester Hills, MI (US);
Paul J. Valente, Berkley, MI (US);
American Axle & Manufacturing, Inc., Detroit, MI (US);
Abstract
A power transmission device includes an actuator having an electric motor driving a pump to supply pressurized fluid to a piston acting on a friction clutch to transfer torque between rotatable input and output members. In one instance, a valve between the pump outlet and the piston selectively traps pressurized fluid acting on the piston without continued energization of the electric motor. A gerotor may be formed from a material having a first coefficient of thermal expansion and a housing formed from a material having a second lower coefficient of thermal expansion to vary pump component clearances as the viscosity of the pumped fluid changes with changes in temperature. A method of controlling the power transmission device includes defining a correlation between pump speed, fluid temperature and fluid pressure, determining fluid temperature, determining pump speed, and rotating the pump to transfer a predetermined quantity of torque.