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:
Aug. 15, 1995
Filed:
Dec. 28, 1993
Seiichi Inukai, Kyoto, JP;
Kenjiro Fujita, Kusatsu, JP;
Akihiro Kondo, Kyoto, JP;
Katsutoshi Usuki, Kyoto, JP;
Mitsubishi Jidosha Kogyo Kaubshiki Kaisha, Tokyo, JP;
Abstract
A hydraulic control device for an automatic transmission including a first frictional engaging element for achieving a low-speed side position, a second frictional engaging element for achieving a position higher in speed than the low-speed side position, a third frictional engaging element for achieving a position even higher in speed than the high-speed side position, a regulator valve for regulating pressure from an oil pump to a predetermined pressure and reducing the predetermined pressure in response to supply of a pilot pressure, and a control valve for controlling the pressure from the regulator valve to a desired hydraulic pressure, for controlling hydraulic pressures to the plural frictional engaging elements. A change-over valve is provided for making the control valve in communication with one of the first frictional engaging element and the third frictional engaging element and supplying and discharging the pilot pressure to the regulator valve, so that the change-over valve is operated by hydraulic pressure supplied to the second frictional engaging element and takes a first position where the control valve communicates with the first frictional engaging element and blocks supply of the pilot pressure to the regulator valve when the supply pressure is lower than a predetermined value, and takes a second position where the control valve communicates with the third frictional engaging element and supplies the pilot pressure to the regulator valve when the supply pressure to the second frictional engaging element is higher than a predetermined value.