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:
Jun. 21, 1983
Filed:
Apr. 10, 1981
Mitsuo Umezawa, Akikawa, JP;
Fuji Jukogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
A speed change control system for an automatic transmission for motor vehicles having a planetary gear mechanism and a brake band for altering the transmission ratio. The system is to tighten gradually the brake band. The system comprises a servo-piston, a piston rod secured to the servo-piston and to the brake band, and an accumulator piston axially slidably disposed in the bore of the servo-piston. The servo-piston is biased by a first spring for returning the servo-piston for releasing the brake band, and the accumulator piston is biased by a second spring. Apply side and release side oil chambers are formed on opposite sides of the servo-piston, and an accumulator oil chamber is formed by the accumulator piston in the bore. Pressure oil is applied to the apply side oil chamber, so that the servo-piston moves in a brake band engagement direction against the first spring. After that, the accumulator piston moves a predetermined stroke against the second spring. Thereafter, the accumulator piston engages with the servo-piston, so that both pistons move together for tightening the brake band.