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:
Aug. 15, 2000
Filed:
Aug. 12, 1999
Tooru Takahashi, Tochigi-ken, JP;
Kenji Nakajima, Tochigi-ken, JP;
Honda Giken Kogyo Kabushiki Kaishi, Tokyo, JP;
Abstract
A plurality of shift control valves for independently controlling the supply of hydraulic oil to, and the discharge thereof from, a plurality of hydraulic engaging elements are divided into a first group of shift control valves which establish a predetermined-speed transmission train and a second group of shift control valves corresponding to the other hydraulic engaging elements. A fail-safe valve is interposed between an oil supply passage which is connected to a hydraulic pressure source and the second group of speed change control valves. The fail-safe valve is switched to a closed position in a condition in which the hydraulic oil is supplied to all of such plurality of hydraulic engaging elements as are not to be engaged at the same time, whereby the oil supply passage is connected only to the first group of shift control valves. Each of the first group of shift control valves is provided with an oil chamber for urging it toward an oil supply position. Each of the oil chambers is connected to the oil supply passage via the fail-safe valve in the closed position thereof. At the time of failure, the line pressure from the oil supply passage is inputted into oil chambers to thereby forcibly switch the first group of shift control valves to the oil supply position. The hydraulic oil is thus supplied to the corresponding hydraulic engaging elements.