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:
Feb. 04, 1992
Filed:
May. 25, 1989
Aisin AW Co., Ltd., , JP;
Abstract
An automatic transmission for an automotive vehicle has a plurality of friction devices for selectively coupling a number of rotary elements in a planetary gear mechanism to one another, and a hydraulic circuit for controlling changeover of the friction devices. The hydraulic circuit includes a regulator valve for generating line pressure, a manual valve for selectively changing over the line pressure to the hydraulic circuit, a plurality of shift solenoids for directly controlling engaging hydraulic pressure of the friction devices by duty control when a shift is made, and a plurality of relay valves controlled by the solenoid valves, wherein the solenoid valves are duty-controlled independently of one another. With such an arrangement, one accumulator is sufficient and the number of valves can be reduced, so that the valve body can be made more compact. In addition, highly precise shock control is possible with regard to all shift conditions.