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:
Feb. 20, 1996
Filed:
Sep. 22, 1994
James R Eaton, Carmel, IN (US);
General Motors Corporation, Detroit, MI (US);
Abstract
An automatic transmission drive ratio control for operating a five speed automatic transmission is provided. The control is particularly adapted for use with a twin countershaft automatic transmission that requires only one torque transfer device for each drive ratio. A system of valves is employed to direct the flow of pressurized fluid necessary for the on-going actuation of each drive ratio and the simultaneous off-going actuation of the previously actuated drive ratio. The flow control for actuating and deactuating the torque control devices is directly effected by a two-position spool valve operating in concert with a rotary valve, pressurized hydraulic fluid used to position the spool valve and the rotary valve is primarily provided by three on/off solenoid shift control valves. A failure of the electrical supply to the solenoid valves will effect a shift to the third drive ratio when the transmission is operating in the first through fourth drive ratios, but will effect a shift to the fifth drive ratio should the electrical failure occur while operating in the fifth drive ratio.