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:
May. 07, 1991
Filed:
Aug. 02, 1989
Mitsuru Takada, Toyota, JP;
Hiroshi Itoh, Toyota, JP;
Tokuyuki Takahashi, Aichi, JP;
Makoto Funahashi, Toyota, JP;
Toyota Jidosha Kabushiki Kaisha, Toyota, JP;
Abstract
For an automatic transmission for a vehicle such as an automobile having a speed stage shifting mechanism including parallelly arranged first and second hydraulically operated input clutches and adapted to provide the 3rd speed stage in which the first and second input clutches C.sub.1 and C.sub.2 are both engaged and the overdrive 4th stage in which the clutch C.sub.1 is disengaged and the clutch C.sub.2 is engaged, the engagement of the clutch C.sub.1 in the 3rd speed stage being not essential unless engine brake availability is required, a hydraulic control device has a hydraulic pressure supply control device for variably controlling speed of supply of a hydraulic pressure to the first input clutch C.sub.1 according to conditions for engaging the first input clutch such whether it is a kickdown of an overdrive inhibition, and a hydraulic pressure exhaustion control device for controlling speed of exhaustion of a hydraulic pressure from the first input clutch C.sub.1 independently of the hydraulic pressure supply control device to be substantially higher than the speed in the supply.