Patent ID: 6494804
Filing Date: 2002-12-17
Classification: F15C,F16H,F16K,Y10T

Abstract:
An electronically controlled automatic transmission, comprising:an input shaft; an output shaft; a plurality of gears providing driving connection between said input shaft and said output shaft; one of a hydraulically operated brake band and a hydraulically operated clutch which is operable to effect a change in the gear reduction provided by said gears between said input shaft and said output shaft; a source of pressurized hydraulic fluid; and a microvalve device selectively operable to control passage of pressurized hydraulic fluid from said source to said one of a hydraulically operated brake band and a hydraulically operated clutch to operate said one of a hydraulically operated brake band and a hydraulically operated clutch, wherein said microvalve device includes a micro-machined pilot valve and a micro-machined pilot-operated valve controlled by the operation of said pilot valve.