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. 10, 1992
Filed:
Dec. 17, 1990
Masami Sugaya, Susono, JP;
Yoshinobu Soga, Susono, JP;
Toyota Jidosha Kabushiki Kaisha, Aichi, JP;
Abstract
A hydraulic control control apparatus for controlling a speed ratio of a vehicle continuously variable transmission, which includes a device for producing a first pressure varying with the input shaft speed of the transmission, a device for producing a second pressure varying with the currently required output of the vehicle engine, a device for producing a third pressure varying with the vehicle speed, such that a rate of increase in the third pressure is limited after the vehicle speed pressure reaches a predetermined upper limit which varies with the second pressure, and a shift control valve device including a valve spool operated to control the hydraulic actuator for changing the speed ratio so as to shift-down the transmission, in relation to an increase in the second pressure and an increase in the vehicle speed pressure, and changing the speed ratio so as to shift-up the transmission, in relation to an increase in the first speed pressure.