Patent ID: 7704179

Claim:
A device for transmission of a torque between two rotatable elements ( 8 ; 16 , 14 ), comprising an internal cogwheel ( 1 ) with N-n teeth engaged with an external cogwheel ( 2 ) with N teeth in a housing ( 3 ), where a first rotatable element ( 8 ; 16 ) with an eccentric ( 7 ; 17 ) is transmission-coupled to the internal cogwheel ( 1 ), characterised in that the eccentric ( 7 ; 17 ) influenced radial pressure-exchanging means ( 10 ) which have contact with a rotationally symmetrical portion ( 11 ; 19 ) of the internal cogwheel ( 1 ) through a housing wall, where each pressure-exchanging means ( 10 ) is encapsulated in a bellows ( 12 ) which is closely connected to the housing ( 3 ), constituting and forming a respective part of the fluid-tight barrier.