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. 29, 2011
Filed:
Mar. 26, 2008
Henryk Sowul, Oxford, MI (US);
Tejinder Singh, Canton, MI (US);
Brian W. Whitmarsh, Commerce, MI (US);
Brian Tooman, Canton, MI (US);
James D. Hendrickson, Belleville, MI (US);
Richard A. Pashnik, Saline, MI (US);
Henryk Sowul, Oxford, MI (US);
Tejinder Singh, Canton, MI (US);
Brian W. Whitmarsh, Commerce, MI (US);
Brian Tooman, Canton, MI (US);
James D. Hendrickson, Belleville, MI (US);
Richard A. Pashnik, Saline, MI (US);
GM Global Technology Operations LLC, Detroit, MI (US);
Abstract
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.