LEAD WIRE SEALING STRUCTURE, METHOD OF MANUFACTURING THE SAME AND GAS SENSOR USING LEAD WIRE SEALING STRUCTURE

PROBLEM TO BE SOLVED: To provide a lead wire sealing structure which does not generate gap between grommet made of a heat-resistant resin and a cylindrical part at heat shrinkage, in constituting the grommet and capable of sure sealing of the grommet to the cylindrical part by the thermal fusion of the grommet to ensure sealability, and to prevent a method of manufacturing the same and a gas sensor using the lead wire sealing structure. SOLUTION: The grommet 51 is provided to the cylindrical part 18, to be formed concentric with the opening part 18c thereof and has a main body pat 51A having a lead wire insertion hole 51a, in which a lead wire 14 is inserted axially and a lateral part 51B which is integrally connected to the body part 51A and of which the inner peripheral surface itself comes into contact with the outer peripheral surface of the cylindrical part 18. Since the inner peripheral surface of the lateral part 51B of the grommet 51, made of a heat-resistant resin, is thermally fused to the outer peripheral surface of the cylindrical part 18, the heat shrinkage of the grommet 51 is generated on the outer surface side of the cylindrical part 18. As a result, a gap is hard to generate between the inner peripheral surface of the lateral part 51B of the grommet 51, and the outer peripheral surface of the cylindrical part 18 and stable sealability can be ensured through thermal fusion.