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:
Nov. 20, 2001
Filed:
Nov. 29, 1999
Masahiro Itou, Anjo, JP;
Hideaki Ogasawara, Anjo, JP;
Naoyuki Fukaya, Anjo, JP;
Takenori Kanou, Anjo, JP;
Yoshihiro Iijima, Toyota, JP;
Other;
Abstract
A hydraulic control device for an automatic transmission that can ensure power transmission when a failure occurs to the solenoid valve of the hydraulic control device, the hydraulic control device having a plurality of hydraulic servos for engaging and disengaging a plurality of friction engagement elements in accordance with the supply and discharge of a hydraulic pressure so as to prevent interlock from occurring to the transmission, a solenoid valve for generating a predetermined hydraulic pressure and supplying the predetermined hydraulic pressure to a hydraulic servo selected in correspondence with a target gear ratio and fail-safe means for supplying fail-safe hydraulic pressure to at least two hydraulic servos selected to attain an arbitrary gear ratio when a failure occurs to the solenoid valve and power transmission thereby becomes impossible. Further, the hydraulic control device has a plurality of solenoid valves for supplying the predetermined hydraulic pressure to the plurality of hydraulic servos and a shutoff valve, disposed between a hydraulic pressure source and one of the solenoid valves, for shutting off supply of hydraulic pressure to that one solenoid valve when hydraulic pressure to be supplied to the hydraulic servos selected in correspondence with the target gear ratio and hydraulic pressure to be supplied to the other hydraulic servos are generated.