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.

Date of Patent:
Sep. 10, 1991

Filed:

Oct. 11, 1989
Applicant:
Inventor:

Motohisa Miyawaki, Nakanoshima, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B60K / ;
U.S. Cl.
CPC ...
180233 ; 180247 ; 180248 ; 180250 ;
Abstract

A control system for a four-wheel drive vehicle with a continuously variable transmission having a drive pulley having a hydraulically shiftable disc and a hydraulic cylinder for operating the disc, a driven pulley having a hydraulically shiftable disc and a hydraulic cylinder, and a pressure regulator valve for regulating pressure of oil supplied to the hydraulic cylinders. A hydraulic actuator is provided for engaging a transfer clutch for establishing four-wheel driving. The pressure regulator valve has a pressure level changing port to increase the pressure of oil supplied to the cylinders. A solenoid operated valve is provided for supplying the oil regulated by the pressure regulator valve to the hydraulic actuator and to the pressure level changing port or for draining the actuator and the port. An orifice is provided in an inlet side of the solenoid operated valve. When the four-wheel driving is selected, the solenoid operated valve is energized to supply the regulated oil to the hydraulic actuator to establish the four-wheel driving.


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