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. 09, 1997
Filed:
Jun. 26, 1996
Ikuo Hirose, Fuji, JP;
Jatco Corporation, , JP;
Abstract
In a hydraulic control device for an automatic transmission for obtaining the optimum shift-down timing by regulating an accumulator back pressure for an engaging element to be engaged in low-speed gear positions, switch control means is provided for communicating an output oil path communicating with an accumulator back pressure chamber, with a selected one of an accumulator control pressure oil path and a drain oil path. The switch control means maintains communication between the output oil path and the accumulator control pressure oil path due to the output feed-back pressure in the N-speed gear position, and brings the output oil path into communication with the drain oil path, using the N+1 pressure as the operating signal pressure, upon shifting-up from the N-speed to N+1-speed gear position. The switch control means also maintains communication between the output oil path and the drain oil path due to a force other than the N+1 pressure in the N+1-speed gear position, and brings the output oil path into communication with the accumulator control pressure oil path, using only the solenoid pressure as the operating signal pressure, upon shifting-down from the N+1-speed to N-speed gear position.