| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method of a spark plug capable of forming a uniform sealant powder layer with high density between an insulation body and a main metal fitting even in the case that the size of the fitting part of a tool is shortened to 14 mm or less, capable of securing sufficient air-tightness and shock resistant property. SOLUTION: The insulation body 2 is inserted into the main metal fitting 1 in the direction of axial line O, and sealant powder 160 is filled into a space 20 in peripheral direction formed between the inner peripheral surface at the rear end of the main metal fitting 1 and the inner peripheral surface of the insulation body 2. The sealant powder 160 is divided into a plurality of small filling units, and preliminarily compressed sealant powders 162a, 162b are formed in the space 20 by repeating the process of filling and preliminarily compressing one small filling unit 161 in the space 20. Afterwards, a prearranged caulking part 1d' is bent toward the outer peripheral surface of the insulation body 2 and fixed by caulking, and the preliminarily compressed sealant powders 162a, 162b are turned into a compressed sealant powder layer 6 fulfilling a relation; 0.5≤M≤1.3, 0.5≤L≤2×(M×4.5), where, the height in the direction of axial line is L mm, and the thickness in the radial direction of axial line is M mm. COPYRIGHT: (C)2003,JPO
|
