US Patent 7631739 Dual wet clutch with an electric machine

A dual clutch for a transmission with a first transmission input shaft and a second transmission input shaft that is positioned in coaxial relation to the first transmission input shaft. The dual clutch comprises a clutch portion comprising a hollow cylinder portion for transmitting torque, wherein the hollow cylinder portion is provided in a radial position between a clutch axle and a clutch hub, is rotatable in relation to the clutch axle and the clutch hub, and comprises at least one opening allowing oil to be fed from the clutch axle to the clutch hub. This design allows supply of hydraulic oil, sufficient cooling oil, and at the same time flexibility in attaching auxiliary engines such as an electromotor to the dual clutch.