Adjustable camshaft drive

A camshaft drive for an internal combustion engine having valves, the camshaft drive comprising:

• a) a drive shaft having at least one cam for actuating one of the valves of the internal combustion engine;
• b) a shaft-in-shaft system disposed parallel to said drive shaft, said shaft-in-shaft system having an inner shaft and an outer shaft, said outer shaft being disposed coaxial to said inner shaft and surrounding said inner shaft;
• c) said inner shaft and said outer shaft each having at least one cam for actuating one of the valves of the internal combustion engine;
• d) an outer shaft transmission element, said outer shaft being coupled to said drive shaft via said outer shaft transmission element, said outer shaft being connected to said outer shaft transmission element in a manner fixed against relative rotation;
• e) a hydraulic transmission device including a stator, a rotor, and an intermediate member disposed between said rotor and said inner shaft, said inner shaft being coupled to said drive shaft via said hydraulic transmission device;
• f) an adjusting device and a control device, said hydraulic transmission device being operatively connected to said adjusting device and to said control device for setting a desired phase angle between said inner shaft and said outer shaft, said control device including at least one device selected from the group consisting of an open loop control device and a closed loop control device;
• and
• g) a drive element coupled to said drive shaft, said drive element being directly coupled both to said outer shaft transmission element and to said stator, wherein said outer shaft transmission element is an outer shaft gearwheel, said drive element is a drive gearwheel, said outer shaft gearwheel meshes with said drive gearwheel, and said stator has an outer toothing which also meshes with said drive gearwheel.