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:
Dec. 24, 1991
Filed:
Mar. 19, 1990
Yoshiaki Hamasaki, Osaka, JP;
Takao Tamagawa, Osaka, JP;
Shuzo Hirakushi, Osaka, JP;
Yoshihiro Nakagawa, Osaka, JP;
Koyo Seiko Co., Ltd., Osaka, JP;
Abstract
A hydraulic transmission coupling apparatus which is used instead of a center differential or a viscous coupling being usually mounted between a front wheel drive shaft and a rear wheel drive shaft of a four-wheel drive vehicle, and transmits driving force existing between the two shafts. The hydraulic transmission coupling apparatus is provided with a vane-type hydraulic pump which generates hydraulic pressure corresponding to a relative rotation speed difference of the two drive shafts and a variable throttle valve being disposed in the passage connecting a discharge port of the hydraulic pump with a tank, whose opening area varies according to the hydraulic pressure generated by the hydraulic pump, thereby driving force to be transmitted being increased or decreased steeply as the rotation speed difference becomes larger.