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. 31, 1984
Filed:
Jul. 28, 1981
Toyota Jidosha Kabushiki Kaisha, Toyota, JP;
Abstract
An automatic transmission includes a gear transmission mechanism with first and second friction mechanisms which are alternatively engaged by alternative supply of first and second actuating pressures thereto when the highest speed stage and the next to highest speed stage are alternatively engaged, and a torque converter including a lockup clutch. A transmission control system includes a pressure control system which controls the gear transmission mechanism by selectively supplying those actuating pressures and possibly others, and a lockup clutch control valve which controls the engagement of the lockup clutch. The lockup clutch control valve is switched to its disengage position when it receives neither a first nor a second control pressure, and is switched to an opposite position by supply of either the first or second control pressure, this opposite position being an engage position for the lockup clutch if governor pressure is over a first specified value. The first control pressure is provided when governor pressure is higher than a second specified value higher than the first specified value and also the first actuating pressure is present; and the second control pressure is provided, if governor pressure is over the first value, when the throttle pressure is lower than a third specified value and also the second actuating pressure is present.