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:
Nov. 20, 2001
Filed:
May. 23, 2000
Jeffrey Kurt Runde, Fishers, IN (US);
Phillip Franklin Mc Cauley, Zionsville, IN (US);
Charles Francis Long, Pittsboro, IN (US);
General Motors Corporation, Detroit, MI (US);
Abstract
A power transmission includes a plurality of torque transmitting mechanisms controlled by an electro-hydraulic control system to provide a reverse drive ratio, a neutral condition and a plurality of forward drive ratios. The electro-hydraulic control has three shift valves, two variable pressure control valves, and a manual control valve. Each of the shift valves have a hydraulically on position, established by a respective solenoid valve, and a hydraulically off position, established by a spring. The manual control valve is moveable to a neutral condition, a reverse drive condition and a forward drive condition. In each of the positions during a neutral to reverse, neutral to forward, or forward/reverse interchange, the shift valves are conditioned to be hydraulically on thereby permitting the manual control valve to be the controlling valve member for completing the interchange. When the reverse ratio is established, the manual control valve directs fluid pressure from one of the variable pressure control valves to one of the shift valves to assist the respective spring and urge the shift valve to the hydraulically off position. During the reverse ratio, neutral condition and the first forward ratio one of the torque transmitting mechanisms is continually engaged.