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:
Jan. 30, 1996
Filed:
Aug. 16, 1994
Toshihisa Marusue, Hiroshima, JP;
Mazda Motor Corporation, Hiroshima, JP;
Abstract
An automatic transmission control system has a plurality of frictional coupling elements within an automatic transmission which are selectively locked and unlocked in a particular way to place the automatic transmission into any desired gear in various ranges. Two specific frictional coupling elements, such as a low/reverse brake and a 3/4 clutch, may potentially cause mechanical locking of the automatic transmission when they are locked simultaneously. The automatic transmission control system, however, includes a first valve for connecting and disconnecting a supply of hydraulic pressure to the low/reverse frictional coupling element to lock and unlock the low/reverse frictional coupling element in low speed and reverse ranges, and a second valve for connecting and disconnecting a supply of hydraulic pressure to the 3/4 frictional coupling element to lock and unlock the 3/4 frictional coupling element. The first and second valves are disposed in series between a hydraulic pressure source and the low/reverse frictional coupling element and cooperate with each other so as to connect supply of hydraulic pressure alternatively to the low/reverse frictional coupling element and the specific frictional coupling element.