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. 22, 1987
Filed:
Jul. 02, 1986
Masahiro Ohkubo, Kadoma, JP;
Kabushiki Kaisha Daikin Seisakusho, Osaka, JP;
Abstract
In an automatic transmission having a four-element two-stage torque converter and a planetary gear transmission which carries out a change-over operation of drive stage of plural planetary gear elements by hydraulically engaging and disengaging plural friction elements from the rear stage of the torque converter transmitting engine power by means of fluid; a drive stage control mechanism for automatic transmission, in which a piston carrying out the engagement and disengagement of the friction members by means of hydraulic force. The pressure surface of the piston is formed into plural concentric stepped surfaces. A pressure oil passage port interconnecting with a control valve for controlling charge and discharge of hydraulic pressure is provided at any one stage of the plural stepped surfaces. A passage leading the hydraulic pressure from such any one stage to another stage and having a throttling function is provided. An elastic member effecting a pressure force on a friction element when engaging the friction element is provided between the piston and the friction element.