Clutch pressure control based on output shaft speed

摘要

In a powershift transmission system the output shaft and driveline unwind and then wind up during shifting under load as the torque applied to the shaft through a first clutch is reduced and the torque applied to the shaft through a second clutch is increased. The degree of winding or unwinding is dependent on the load being driven by the shaft and is manifested as an apparent increase or decrease in the rate of rotation of the output shaft as measured at the transmission end of the shaft. The rate of rotation of the transmission output shaft is sensed during shifting and the second clutch pressure is controlled in accordance with the sensed rate of rotation so that the second clutch pressure varies according to the load. The arrangement reduces sudden accelerations under no-load conditions but permits near optimum clutch pressures at heavier loads.