Signal wheel for generating rotational position signal

摘要

A tone wheel for generating electrical pulses at a rate proportional to the rotational speed of a road wheel. The tone wheel is stamped from sheet steel stock and is characterized by elongated, axially extending teeth supported in cantilever fashion from one end on roots extending radially from a center portion of the tone wheel. The teeth are spaced from each other and for a major portion of their length are free of adjacent structure so that they produce a sharp pulse when scanned by a sensor and are self-cleaning to reduce the risk of accumulating dirt and debris which can otherwise result in destruction of the sensor. In other embodiments of the invention, a signal wheel is a composite of a ferromagnetic steel and a non-magnetic material such as plastic. The non-magnetic material serves to block entry of debris or oil into the gaps between the teeth thereby reducing the risk of damage from solid debris or reducing churning and aeration of oil in which the wheel may run.