A power transmission unit includes a first input shaft and a second input shaft which can be mutually driven by a motor shaft in opposite directions. A driven shaft can be coupled, depending on the desired sense of rotation of the driven shaft, to the first or to the second input shaft, and can engage with a first output shaft and with a second output shaft. The first output shaft can be directly coupled with the first input shaft via a first magneto-rheological clutch, and the second output shaft can be directly coupled with the second input shaft via a second magneto-rheological clutch. A magneto-rheological clutch includes a coil powered by wireless energy transmission between a sender connected to a stationary housing and a receiver rotating with the coil.
