| 摘要 |
Continuously variable speed ratio transmissions (CVT) for an in-wheel application use one or more magnetorheological (MR) or oil-shear clutch assemblies, each of which can have a unique speed ratio, to transmit torque between an input shaft and an output shaft. The clutch assemblies comprise an input drive element, input idler assemblies, a number of clutch assemblies output idler assemblies, and an output shaft assembly. Preferably, the CVT can be structured and arranged to occupy a volume between about 10- and 11-inches in diameter and between about 4 and 5 inches in axial length. The MR clutch assembly includes a rotateable input cylinder and a rotateable output cylinder that are coaxial about a stationary shaft. The input cylinder and output cylinder are separated by a gap that is filled with an MR fluid. A multitude of coil windings are disposed on the stator of each of the MR clutch assemblies. When current flows through the coil windings, a magnetic flux field is produced in the MR fluid. The MR fluid densifies, transferring input cylinder torque to the output cylinder by shear. A control unit can control current to the coil windings so that only clutch assemblies having the desired speed ratio are actuated. Alternatively, a CVT comprises a number of oil-shear clutch assemblies, each of which can have unique speed ratios, to transmit torque between a rotateable clutch cylinder and a rotateable drive cup and hub assembly through shear in the oil and/or through direct contact between the two cups. A control unit can control an external pressure that can be added to one or more of the oil-shear clutches to increase of decrease the separation distance between the two cups to provide the desired speed ratio. A CVT with a moveable magnetic flux producing device to produce a localized magnetic flux field in MR fluid that is disposed in the gap between a rotatable internal drive element and a rotateable external drive element. The speed ratios associated with various positions device differ, providing an infinite variable speed ratio transmission.
|
