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:
Apr. 03, 1990
Filed:
Mar. 29, 1989
Seiji Ohmura, Toyota, JP;
Yuji Itoh, Toyota, JP;
Toyota Jidosha Kabushiki Kaisha, Aichi, JP;
Abstract
In a device for controlling the flow rate of a hydraulic operating fluid from a pump to a hydraulic motor for driving an engine cooling fan in a vehicle by modifying either the cross sectional opening area of a variable flow constriction means in the fluid conducting passage while maintaining a constant pressure difference across the flow constriction means by a pressure control valve responsive to the pressure difference across the flow constriction means or the pressure difference by selectively partly leaking the pressure transmitted from the downstream side of the flow constriction means to a rear side of the pressure control valve, a cold state relief means is provided to temporarily relieve the rear side of the pressure control valve at cold start of the engine to avoid abnormally high fluid pressure being supplied to the motor due to delayed response of the pressure control valve under high viscosity of the operating fluid at low temperature.