GLOW PLUG AND ITS MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a glow-plug manufacturing method allowing the smooth force fit of a ceramic heater and a metal outer tubing and the glow plug manufactured by the method. SOLUTION: The glow plug 50 is provided with a rod-like ceramic heater 1 with a resistance heating element 11 buried inside itself, the metal outer tubing 3 mounted to the outer peripheral surface of the ceramic heater 1 by force fit and principal metal fittings 4 holding the metal outer casing 3. On the inner peripheral surface of at least one end part in the direction of an axis O of the metal outer tubing 3, a taper surface 3p enlarging in diameter toward the opening end in the direction of the axis O is formed. The taper surface 3p contributes to the smooth force fit of the ceramic heater 1 to the metal outer tubing 3.