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. 23, 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 including a speed stage shifting device such as shown in FIG. 1 in which the clutch C.sub.1 is adapted to be engaged when the 2nd speed stage and the 3rd speed stage are set up and disengaged when the 4th speed stage is set up, the engagement of the clutch C.sub.1 being essential for setting up the 2nd speed stage while the engagement of the clutch C.sub.1 is not essential for setting up the 3rd speed stage unless engine brake availability is required, a hydraulic control device includes a first passage 235 and a second passage 329 for supplying a hydraulic pressure to the clutch C.sub.1 in parallel with one another, the first passage having a substantially less fluid flow resistance than the second passage, and a fluid flow switching over mechanism including a 1-2 shift valve 210 and a C.sub.1 control valve 300 for alternatively communicating the first or the second passage while interrupting the second or the first passage according to whether the 2nd speed stage or the 3rd speed stage is set up. An accumulator 450 may be provided in the second passage 329. Further, a one way val e 469, or more desirably a parallel connection of the one way valve 469 and an orifice 467 may be provided between the accumulator and the clutch C.sub.1.