Abstract: A method for heat treating a bearing ring includes performing an induction heating treatment and a liquid spraying treatment on a first radial surface so that a radial thickness of the bearing ring is hardened, performing an induction heating treatment on an opposite radial surface so that the temperature near the opposite radial surface reaches 820-950° C., and at the same time spraying liquid on the first radial surface so that the temperature of the first radial surface does not exceed 150° C., spraying liquid on the second radial surface after the induction heating treatment so that the bearing ring forms a hardened second radially outer portion, a hardened second radially inner portion, and a second radially middle portion having a hardness lower than that of the second radially outer portion and the second radially inner portion, and then performing a low-temperature tempering treatment on the bearing ring.

Abstract: The invention provides a sensor, which includes a sensing surface; a housing including a recess, the sensing surface is located at the bottom of the recess, and the recess includes at least one side wall and an opening circumferentially surrounding the sensing surface. A compressed fluid nozzle is provided in the at least one side wall to nozzle compressed fluid from the compressed fluid nozzle to force the substance on the sensing surface to leave from the opening. This design makes it possible to refresh in situ with good efficiency without involving additional mechanical parts, thus reducing the risk of sensing surface damage, such as scratch wear, in the presence of wear particles.