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:
Mar. 20, 1990
Filed:
Sep. 28, 1988
Tatsuya Iwatsuki, Okazaki, JP;
Takenori Kano, Anjo, JP;
Fumitomo Yokoyama, Anjo, JP;
Yasunari Nakamura, Nogoya, JP;
Isamu Minemoto, Okazaki, JP;
Teruo Akashi, Nagoya, JP;
Masaharu Tanaka, Toyota, JP;
Seitoku Kubo, Toyota, JP;
Aisin AW Co., Ltd., Anjo, JP;
Toyota Jidosha Kabushiki Kaisha, Toyota, JP;
Abstract
A power transmission device for four wheel drive vehicle includes a differential motion limiting device, for limiting differential motion of a center differential device, which is made up by a wet-type frictional clutch and a hydraulic actuator. Under running condition, the frictional clutch is engaged by certain engaging force, and considering frictional coefficient of roads, the clutch is engaged with some slips so that torque distribution to front and rear wheels becomes even (50:50), then torque is distributed from the center differential device to front and rear wheels. The line pressure is applied to the hydraulic actuator through a regulator valve. In normal running condition, the regulator valve reduces the line pressure pre certain ratio, the reduced pressure is applied to the hydraulic actuator. In the case the manual valve being shifted to R range or low speed position, the regulator valve is switched to apply the line pressure directly to the hydraulic actuator. In the case of the manual valve being shifted to a low speed position, then from the low speed port of the manual valve, the line pressure is applied to a modulator valve where the line pressure is modulated, and applied to a back pressure port of a primary regulator valve to boost the line pressure up to certain volume.