Patent ID: 7181840
Filing Date: 2007-02-27
Classification: B23K,G01N,Y10T

Abstract:
1. A gas sensor manufacturing method comprising the steps of: preparing an assembly which has a length and includes (a) a housing which has a length made up of a first end portion, a second end portion, and a flange between the first and second end portions, (b) a cover which is made up of a small-diameter portion, a large-diameter portion, and a shoulder formed between the small-diameter portion and the large-diameter portion, (c) a first insulation porcelain disposed in the large-diameter portion of the cover in contact with the shoulder through an elastic member, (d) a second insulation porcelain disposed in the housing in contact of an end thereof with an end of the first insulation porcelain in alignment with each other, and (e) a laminated sensor element disposed in the second insulation porcelain; preparing a first press member to be stationary which retains the second end portion of the housing firmly; moving a second press member at a first speed into abutment with the shoulder of the cover; decreasing a speed of movement of the second press member after the abutment of the second press member with the shoulder of the cover and moving the second press member at a second speed, lower than the first speed, to press the cover against the housing in a lengthwise direction of said assembly until a given pressure is exerted on the shoulder to deform the elastic member and to fit an end of the large-diameter portion of the cover on the first end portion of the housing to form an overlap; and welding the large-diameter portion of the cover to the first end portion of the housing at the overlap while pressing the cover against the housing.