| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a gas sensor preventing corrosion in a weld of a main fitting and an outer cylinder, and also to provide a manufacturing method thereof. <P>SOLUTION: In a gas sensor the top end 66 of an outer cylinder 65 is engaged in the rear-end engagement portion 57 of a main fitting 50 and the portion engaged by them is laser-welded over the entire periphery in the radial direction about the abutment position (the vicinity of the border of them shown by an arrow B). A welded portion 99 melted by laser irradiation is formed astride the top end 66 of the outer cylinder 65 and of the cylinder 571 of the main fitting 50. This welded portion 99 seals the gap between the end surface 69 of the outer cylinder 65, which becomes an entrance portion to the gap between the inner peripheral surface 68 of the outer cylinder and the outer peripheral surface 573 of the rear end engagement portion 57 of the main fitting 50, and the rear end facing surface 574 of the engagement portion 57. This prevents water drops from infiltrating into the gap. Corrosion is thereby prevented which is likely to occur when water drops are in contact with the welded portion 99 over a long period. <P>COPYRIGHT: (C)2009,JPO&INPIT |
