Gm Global Technolgoy Operations, Inc.

Brian E Tooman

Henryk Sowul

Daryl A Wilton

John A Diemer

Tejinder Singh

James D Hendrickson

Patrick S Portell

Brian W Whitmarsh

Richard A Pashnik

Ryan M Jenness

Robert Roessner

A multiple shift fork, single shift rail assembly reduces weight and complexity in manual and dual clutch transmissions. In a first embodiment, a stationary shift rail includes pluralities of detenting recesses and cooperating detent assemblies are mounted on the shift forks. Associated actuators translate the shift forks and synchronizer clutches. In a second embodiment, the detenting recesses reside on the outside surface of the shift forks and the detent assemblies are mounted in the transmission housing. In a third embodiment, one shift fork is slidably mounted on the shift rail and includes an external detent assembly. The shift rail itself translates and includes detenting recesses and a second shift fork connected thereto.

Dual fork single shift rail assembly

A synchronizer actuating system with selectives for use in dual clutch transmission is provided. The synchronizer actuating system includes an apply finger and a fork mounted on a shift rail. The fork grips a synchronizer sleeve that supports a synchronizer. The synchronizer is moveable to a neutral position. A three area piston assembly is operable to engage and actuate the apply finger. The three area piston assembly includes a hydraulic neutral position. A selective element is coupled to the synchronizer actuating system to calibrate the hydraulic neutral position of the three area piston assembly to the neutral position of the synchronizer sleeve.

Synchronizer actuating system with selectives

The present invention provides a three position hydraulic piston assembly for a gear ratio change mechanism for a transmission exhibiting reduced gear shift noise. The three position hydraulic piston assembly includes a master piston and motion retarding assemblies that act near both travel limits of the master piston. The master piston includes symmetrical passageways that provide hydraulic fluid flow to small chambers at each end of the piston that are closed off as the piston approaches its travel limits. Hydraulic fluid trapped in the chambers decelerates the piston and is bled off through an orifice allowing the piston to reach its travel limit and quickly and quietly engage a gear ratio.

Hydraulic actuator for transmissions having reduced noise

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White Lake, MI, United States of America

Brian E Tooman