| 摘要 |
<p>A ring gear (CR) of a planetary gear train (24) for distribution constituting a front and rear wheel power distribution unit (14) is coupled to a differential output member (22), a carrier (CCA) thereof is coupled to a rear wheel, a sun gear (CS) thereof is coupled to a front wheel, and an automatic transmission (30) capable of shifting the gear from the speed reducing transmission gear ratio to the speed increasing transmission gear ratio is disposed in a rear-wheel power transmission path. If the gear is shifted to the speed increasing transmission gear ratio during high-speed running, the rear-wheel transmission gear ratio ?r becomes lower than the front-wheel transmission gear ratio ?f and the rotational speed of the differential output member (22) is reduced. As a result, the energy circulation for rotationally driving a first motor generator (MG1) in a reverse rotational direction is suppressed, leading to improved energy efficiency. If the gear is shifted to the speed reducing transmission gear ratio during accelerated running, the rear-wheel transmission gear ratio ?r becomes higher than the front-wheel transmission gear ratio ?f and the rotational speed of the differential output member (22) is increased. As a result, an increase in the engine rotational speed (NE) is allowed, leading to improved power performance.</p> |
