Patent ID: 7845460
Filing Date: 2010-12-07
Classification: B62D

Abstract:
1. Rotational speed superposition device for a motor vehicle steering system comprising: an output drive shaft ( 1 ) oriented with respect to an input drive shaft ( 2 ) in an axial direction of the output drive shaft, a fixed carrier arrangement ( 4 ) which rotatably supports the output drive shaft ( 1 ) and the input drive shaft ( 2 ) so that the output drive shaft and the input drive shaft are at least partially bearing supported, an auxiliary drive ( 5 , 6 , 7 ) with a rotor ( 7 ), connected torsion-tight with a first gearing element ( 19 , 25 , 27 ) and an adjustable locking device ( 10 ) for a selectable torsion-tight coupling between the output drive shaft ( 1 ) and the input drive shaft ( 2 ), wherein the carrier arrangement ( 4 ) is stationary with respect to a body of the motor vehicle, the rotor of the auxiliary drive ( 5 , 6 , 7 ) being coaxial to at least one of the output drive shaft ( 1 ) and the input drive shaft ( 2 ), the first gearing element ( 19 , 25 , 27 ) having a rotational speed transmission ratio of less than 1 and transmitting a rotational speed of the rotor ( 7 ) onto rotational speed of the output drive shaft ( 1 ), and the rotor ( 7 ) being connected torsion-tight with a ferromagnetic or permanent magnetic first contact element ( 8 ) concentrically encompassing the axial direction of the output drive shaft ( 1 ) and input drive shaft ( 2 ), wherein the selectable torsion-tight coupling between output drive shaft ( 1 ) and input drive shaft ( 2 ) is attained through a frictional locking of the first contact element ( 8 ) with a second contact element ( 9 ) connected torsion-tight with the carrier arrangement ( 4 ) and a press-on force required for the friction force is generated through a magnetic force and wherein at least one of the two contact elements ( 8 , 9 ) is displaceable in the axial direction, the locking device ( 10 ) being a separate compact unit arranged in a separate housing part ( 17 ) and being separate from the first gear element ( 19 , 25 , 27 ) and the auxiliary actuator drive ( 5 , 6 , 7 ), the auxiliary drive ( 5 , 6 , 7 ) being between the first gear element ( 19 , 25 , 27 ) and the locking device ( 10 ) with respect to the input drive shaft ( 2 ), and a coupling element ( 15 ) between the rotor ( 7 ) and the first contact element ( 8 ) for non-rotatable coupling between the rotor ( 7 ) and the first contact element ( 8 ).