Patent ID: 7806796

Claim:
A power device for motor vehicles, comprising: a planetary gear mechanism, which has an input side, an output side and a control terminal, wherein the input side is connected to an output shaft of the motor vehicle's engine, and the output side is connected to a power output shaft of the power device for motor vehicles via a mechanical transmission mechanism; a first variable displacement hydraulic actuator, which is connected to the control terminal of the planetary gear mechanism and is connected to an oil tank via hydraulic lines; a second variable displacement hydraulic actuator, a rotation shaft of which is connected to the power output shaft of the power device for motor vehicles, and which performs power input or output via the power output shaft and is connected to the first variable displacement hydraulic actuator and the oil tank via hydraulic lines, respectively; an electronic control device, which collects operation parameters of the motor vehicle and control parameters over the motor vehicle, and output control signals according to these parameters; the first and second variable displacement hydraulic actuators carry out variable displacement adjustments in response to the control signals from the electronic control device; a hydraulic control device, which is arranged on the hydraulic lines and controls the operating states of the first and second variable displacement hydraulic actuators in response to the control signals from the electronic control device, wherein the mechanical transmission mechanism comprises a parallel two or more stage shifting gear pairs; between the two or more stage shifting gear pairs and the output side of the planetary gear mechanism is respectively provided with an overrunning clutch; and between the parallel two or more stage shifting gear pairs is respectively provided with a second clutching device; the overrunning clutch and the second clutching device adjust the transmission ratios of the mechanical transmission mechanism through clutching action, respectively.