Patent ID: 8721486

Claim:
A continuously variable transmission comprising a variator comprising an input disk coupled to an input shaft, an output disk providing a rotary variator output, the input and output disks being mounted for rotation about a common axis, at least one roller arranged between the two disks to transfer drive from one disk to the other at a continuously variable variator drive ratio, the roller being mounted in a carrier in a manner which permits it to spin about its own axis and to tilt relative to the disks to vary the variator drive ratio, and a hydraulic actuator arranged to apply to the carrier a reaction force determined by a hydraulic pressure difference acting on the actuator, the reaction force opposing a fraction force applied to the roller by the action of the disks; power-recirculation gearing which receives as inputs the rotation of the input shaft and the rotary variator output, and which produces an output speed which is a function of both its inputs; a low/high switching mechanism which comprises a low clutch and a high clutch and which serves to switch between (a) a low regime in which the low clutch is engaged and the output of the power-recirculation gearing is transmitted to an output shaft, and (b) a high regime in which the high clutch is engaged and rotation of the variator output is transmitted to the output shaft, and wherein the direction of the reaction force of the hydraulic actuator is reversed during switching between low regime and high regime, the transmission comprising: an engagement control which starts to engage a disengaged clutch (which may be the low clutch or the high clutch) when the transmission reaches a condition at which regime change is to be initiated; and a reaction force switching control which starts the reversal of the reaction force direction while the disengaged clutch is being engaged.