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:
Jun. 09, 1992
Filed:
Dec. 17, 1990
Masami Sugaya, Susono, JP;
Yoshinobu Soga, Susono, JP;
Toyota Jidosha Kabushiki Kaisha, Aichi, JP;
Abstract
A hydraulic control apparatus for controlling a continuously variable transmission for a motor vehicle, including a shift control valve device having a valve spool adapted to receive a first thrust corresponding to the currently required engine output and a second thrust corresponding to the input shaft speed of the transmission such that the spool is biased by the first and second thrusts in a shift-down and a shift-up direction for shifting down and shifting up the transmission, respectively, so that the speed ratio of the transmission is changed according to a distance of movement of the spool from a neutral position thereof in one of the shift-down and shift-up directions. The apparatus includes a device for producing a control pressure which varies with the vehicle speed, a gain changing spring for changing the distance of movement of the valve spool by the thrusts, and a device for permitting a biasing force of the spring to act on the spool, based on the control pressure, such that the distance of movement of the spool by the thrusts decreases with an increase in the vehicle speed.