Vehicle speed sensor

Abstract

A speed sensor (10) includes a sensor housing (12) mounted to the wall of a transmission, and a pole piece (34) extends out of the sensor housing (12) into the transmission fluid. The pole piece (34) is held by a plastic spool (26) within the sensor housing (12), and an electric coil (28) surrounds the spool (26) and is magnetically coupled to the pole piece (34). The spool (26) is formed with a rib ring (41) that extends away from the pole piece (34) and that terminates in an outer periphery that is closely spaced from the inside wall of the sensor housing (12). To block metal particles in the fluid from entering between the spool (26) and sensor housing (12) that would otherwise damage the coil (28), two ribs (60) are formed on the outer periphery of the spool (26), and an interference fit is established between the ribs (60) and the sensor housing (12) such that the ribs (60) are deformed and the contaminants thereby blocked.

Dependencies are inferred from the claim text.