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. 20, 2002
Filed:
May. 29, 2001
Hirohisa Tanaka, Meguro-ku, Tokyo, JP;
Hidetaka Koga, Kanagawa, JP;
Other;
Abstract
A device for changing the speeds of the front and rear wheels in a four-wheel-drive vehicle, which is equipped with a continuously variable speed-changing mechanism for the front wheels which changes the input rotational speed and outputs it to the front wheel drive shafts and a continuously variable speed-changing mechanism for the rear wheels which changes the input rotational speed and outputs it to the rear wheel drive shafts. The device for changing the speeds of the front and rear wheels comprises a detector means for detecting the operation conditions of the vehicle and a controller for variably controlling the speeds of said continuously variable speed-changing mechanism for the front wheels and of said continuously variable speed-changing mechanism for the rear wheels based on the operation conditions of the vehicle detected by said detector means. The controller calculates a tire diameter ratio of the front wheels to the rear wheels when the vehicle travels straight, sets a target speed-changing ratio obtained based on the vehicle operation conditions detected by the detector means to be a target speed-changing ratio for the rear wheels in the continuously variable speed-changing mechanism for the rear wheels or to be a target speed-changing ratio for the front wheels in the continuously variable speed-changing mechanism for the front wheels, and sets a speed-changing ratio obtained by correcting the target speed-changing ratio based on the tire diameter ratio to be a target speed-changing ratio for the front wheels or to be a target speed-changing ratio for the rear wheels.