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:
Mar. 30, 1999

Filed:

Oct. 14, 1997
Applicant:
Inventors:

Tsunefumi Niiyama, Saitama, JP;

Yasushi Ohmatoi, Saitama, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
F16H / ; F16H / ;
U.S. Cl.
CPC ...
477 49 ; 477 46 ; 474 28 ;
Abstract

A hydraulic control apparatus for a continuously variable transmission which can produce stable drive pulley pressure and driven pulley pressure and also control the speed change time. The line pressure regulated by the regulator valve 22 is supplied to the control valve 24.sub.DR of the drive pulley 5 and to the control valve 24.sub.DN of the driven pulley 7. These control valves regulate the line pressure according to the PB pressure and the PC pressure output from the solenoid valves SOL-B, SOL-C, respectively, and produce the drive pulley pressure P.sub.DR and the driven pulley pressure P.sub.DN. When the PB pressure and the PC pressure are both zero, and P.sub.DR =P.sub.DN, the control apparatus maintains the same gear ratio. When the PB pressure is increased from zero while keeping the PC pressure at zero, i.e. P.sub.DR >P.sub.DN, the gear ratio changes toward the high-speed overdrive. When the PC pressure is increased from zero while holding the PB pressure at zero, i.e. P.sub.DR <P.sub.DN, the gear ratio changes toward the low-speed gear.


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