Motion detector according to the ferraris principle

#This application claims the priority of German Patent Application, Serial No. 102 16 635.8, filed Apr. 15, 2002, pursuant to 35 U.S.C. 119(a)-(d), the disclosure of which is incorporated herein by reference.

#The present invention relates to a motion detector according to the Ferraris principle with an excitation assembly, an electrically conductive induction element and a sensor assembly.

#Motion detectors of this type are known in the art. The excitation assembly of these motion detectors has at least one excitation element capable of applying an inhomogeneous magnetic field to the induction element. When the induction element moves, an eddy current is induced in the induction element due to the motion and the magnetic field. The sensor assembly has at least one sensor element for a measuring a measurement signal which is proportional to the changes in the eddy current induced in the induction element.

#Other features and advantages of the present invention will be more readily apparent upon reading the following description of currently preferred exemplified embodiments of the invention with reference to the accompanying drawing, in which:

#FIG. 1 shows a side view of one embodiment of a motion detector according to the Ferraris principle;

#FIG. 2 shows a top view of the motion detector of FIG. 1;

#Throughout all the Figures, same or corresponding elements are generally indicated by same reference numerals. These depicted embodiments are to be understood as illustrative of the invention and not as limiting in any way.

#Turning now to the drawing, and in particular to FIGS. 1 and 2, there is shown a motion detector according to the Ferraris principle which includes an excitation assembly 1, an induction element 2, a sensor assembly 3 and a signal processing circuit 4. The induction element 2 is made of a non-magnetic, electrically conductive material, e.g., copper. In the configuration of the motion detector depicted in FIGS. 1 and 2, the induction element 2 performs a rotary motion about a rotation axis 5. However, the induction element 2 can also perform a translatory motion.

#As also seen in FIGS. 1 and 2, the excitation assembly 1 includes an excitation element 6. The excitation element 6 of FIG. 1 is implemented as a coil 6, with the magnetic field of the coil being amplified and directed by a U-shaped coil core 7. The arms of the coil core 7 shown in FIG. 2 are arranged to the left and to the right of the line 8. The excitation element 6 itself is indicated in FIG. 2 by a dashed line.