SEAMLESS TWO-SPEED TRANSMISSION FOR ELECTRIC VEHICLE

摘要

A two-speed transmission comprises a first planetary gearbox including a sunincludingat least one sun gear, a ring including at least one ring gear, first planetgears meshed with thesun and the ring, a first planet carrier operatively supporting the firstplanet gears, the firstplanet carrier being an input of the two-speed transmission. A secondplanetary gearboxincludes the sun and the ring in common with the first planetary gearbox,second planet gearsmeshed with the sun and the ring, and a second planet carrier operativelysupporting the secondplanet gears, the second planet carrier being an output of the two-speedtransmission. A sunbrake brakes the sun and a ring brake brakes the ring. The sun and/or the ringincludes twogears connected together, the two gears having different diameters for thetransmission to haveat least two speed ratios. A first of the speed ratios between the input andthe output isprovided by actuating the sun brake and by releasing the ring brake, and asecond of the speedratios, different than the first speed ratio, is provided by actuating thering brake and byreleasing the sun brake.