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:
Jul. 02, 1991
Filed:
Sep. 06, 1989
Takuji Fujiwara, Hiroshima, JP;
Hiroshi Yoshimura, Hiroshima, JP;
Kozo Ishii, Hiroshima, JP;
Kazuo Takemoto, Hiroshima, JP;
Mazda Motor Corporation, Hiroshima, JP;
Abstract
An automatic transmission has a transmission gear mechanism and a plurality of friction coupling members which are applied or released by hydraulic pressures applied thereto under the control of a hydraulic control system. The control system includes a hydraulic control circuit which controls the hydraulic pressure fed to or discharged from the respective friction coupling member, thereby changing the condition of application of the friction coupling members and causing the automatic transmission to shift. The plurality of friction coupling members includes first and second friction coupling members the conditions of application of which are changed during gear shifting from a first predetermined gear speed to a second predetermined gear speed. The first and second friction coupling members are fed with the hydraulic pressure respectively through first and second hydraulic passages. The hydraulic control circuit is provided with a pressure regulator valve which receives the pressure in the first hydraulic passage as a pilot pressure and regulates the hydraulic pressure to be fed to the second friction coupling member through the second hydraulic passage according to the pilot pressure.