Rotational speed sensor with membrane

摘要

To prevent the adhesion or penetration of iron filings or other magnetically permeable material, thereby avoiding a short-circuit of the magnetic circuit and ensuring an accurate output signal, a membrane comprised of a non-magnetic material covers the bottom of a casing facing a rotor, and a protuberance of a length at least equal to the maximum air gap between the membrane and the rotor is integrally molded to a portion of the membrane.