Variable reluctance rotation sensor with leakage magnetic flux sensing

摘要

A variable reluctance rotation sensor comprising a flux member having a ferromagnetic pole piece formed of a cylindrical center portion interposed between a first and second end portion. Each of the end portions have a respective surface which contains elongated teeth, similarly separated by slots as teeth on the periphery of a toothed wheel. The cylindrical center portion is positioned with respect to the toothed wheel such that the toothed surfaces of the first and second end portions are positioned adjacent the periphery of the toothed wheel comprising the teeth and slots, the magnetic flux member and toothed wheel defining an air gap. The sensor further comprises permanent magnets which establish main flux loops traversing the air gap, and leakage flux loops linking an electrical coil wound about the cylindrical center portion. As the toothed wheel is rotated, the magnitude of the main flux loops vary in relation to the varying air gap. The leakage flux loops, in turn, vary in relation to the varying main flux loops, the varying leakage flux loops being linked to the electrical coil and resulting in a sinusoidal output voltage signal proportional to the varying leakage flux loops. Each cycle of the output signal corresponds to a predetermined incremental angular rotation of the toothed wheel.