Abstract:
A continuously variable transmission is disclosed comprising a transmission input and output between which a variator (V) can be coupled, in either a low regime or a high regime, by gearing (R1, R2, R3, M). The relationship between variator ratio and overall transmission ratio is different in the two regimes. Incorporated in the gearing are first and second clutch means (L, H) both hydraulically actuated, for engaging and disengaging low and high regimes respectively. The gearing provides a synchronous ratio at which a change between low and high regimes, at constant variator ratio, provides no change in the overall transmission ratio. The transmission is provided with hydraulics which incorporate a shift valve (110) which controls application of hydraulic pressures to the first and second clutch means. A change in state of the shift valve (110) causes one clutch means to change from engaged to disengaged and the other to make the opposite transition. In this way changes of transmission regime are hydraulically controlled.
Abstract:
Provided herein is a control system for a multiple-mode continuously variable transmission having a ball planetary variator. The control system has a transmission control module configured to receive a plurality of electronic input signals, and to determine a mode of operation from a plurality of control ranges based at least in part on the plurality of electronic input signals. The control system implements a method for controlling a clutch-to-clutch shift of a continuously variable drive (CVD) having a ball-planetary variator (CVP), wherein the CVP is operably coupled to a multiple speed gear box having a first clutch corresponding to a first selectable operating mode and a second clutch corresponding to a second selectable operating mode.
Abstract:
A continuously variable transmission is disclosed comprising a transmission input and output between which a variator (V) can be coupled, in either a low regime or a high regime, by gearing (R1, R2, R3, M). The relationship between variator ratio and overall transmission ratio is different in the two regimes. Incorporated in the gearing are first and second clutch means (L, H) both hydraulically actuated, for engaging and disengaging low and high regimes respectively. The gearing provides a synchronous ratio at which a change between low and high regimes, at constant variator ratio, provides no change in the overall transmission ratio. The transmission is provided with hydraulics which incorporate a shift valve (110) which controls application of hydraulic pressures to the first and second clutch means. A change in state of the shift valve (110) causes one clutch means to change from engaged to disengaged and the other to make the opposite transition. In this way changes of transmission regime are hydraulically controlled.
Abstract:
A continuously-variable-ratio transmission ("CVT") of the band-and-sheave type capable of "torque control", so that what the operator demands, by movement of the accelerator pedal or other control member, is a particular driving torque applied to the ratio-varying component ("variator"). A connection (21, 22) between at least one of the variator sheaves (3, 4) and its shaft (5) is torque-sensitive, so that torque at that sheave generates an axial force which is a function of the magnitude and direction of the torque to which the sheave is subjected. Examples are described in which the operating axial load, applied to the variator pulley units, comprises two parts -a first part to maintain traction between sheaves and band, and a second part related to the applied torque- and a variator using more than one band.