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. 11, 1987
Filed:
Nov. 26, 1985
Daisaku Sawada, Gotenba, JP;
Masami Sugaya, Susono, JP;
Yoshinobu Soga, Susono, JP;
Ryuji Imai, Toyota, JP;
Toyota Jidosha Kabushiki Kaisha, Aichi, JP;
Abstract
A hydraulic control system for a continuously variable transmission having two variable-diameter pulleys, a belt connecting the pulleys to transmit power from one of the pulleys to the other, and corresponding cylinders for changing effective diameters of the pulleys. The control system comprises: a hydraulic source delivering a pressurized fluid; a first pressure regulating device for regulating the pressurized fluid to apply a first line pressure to one of the cylinders for controlling a tension of the belt; a flow control device for controlling flow of the fluid into and from the other cylinder to change the effective diameters of the pulleys to vary a speed ratio of the transmission; a second pressure regulating device provided between the hydraulic source and the first pressure regulating device to regulate the pressurized fluid to apply a second line pressure to the flow control device, the second line pressure being higher than a pressure in the above-indicated hydraulic cylinder or the first line pressure by a predetermined value; and a releasing device for releasing the second pressure regulating device from its regulating operation while the speed ratio of the transmission is changed with the fluid discharged from the above-indicated other cylinder, or while the speed ratio is held constant.