| 摘要 |
<p>Continuously variable transmission, in particular for a motor vehicle, provided with a primary pulley mounted on a primary shaft, a secondary pulley mounted on a secondary shaft, and a drive belt running over both pulleys, each pulley comprising two sheaves, one of which is movable axially relative to the other under the influence of a hydraulic cylinder, for setting the transmission ratio, a pumping unit with at least two pumps for delivering hydraulic medium to the hydraulic cylinders, and a control unit for controlling the pump delivery depending on the operating conditions of the transmission. The pumping unit comprises at least two pumps, the first of which serves as a booster pump for the second pump connected in series. A switch valve is fitted, by means of which, under the control of the control unit, the two pumps can be switched over from series connection to parallel connection if the volume flow of the medium required by the transmission is greater than the available volume flow in the series connection. <IMAGE></p> |
