Ceramic heater with ring member electrically connecting the heater to lead terminal core rod

摘要

A heater including: a rod-shaped ceramic heater including: a ceramic heater body extending in an axial direction and having a heating-element at its leading end portion for generating heat when energized; and first and second energizing lead terminals extending from the heating element and exposed to an outer circumference of a trailing end side of the ceramic heater body; a cylindrical outer cylinder for holding the ceramic heater while protruding a leading end portion and a trailing end portion of the ceramic heater; and a core rod arranged on said trailing end side of the ceramic heater in an axial direction and connected electrically with the first lead terminal, wherein the heater further includes: a ring member including: a ring leading end portion fixed by a tight fitting on an outer circumference of a trailing end side of the ceramic heater and connected electrically with the first lead terminal; and a ring trailing end portion protruding backward from a trailing end of the ceramic heater; and a metallic lead for connecting the ring trailing end portion and the core rod electrically.