Patent ID: 7569792
Filing Date: 2009-08-04
Classification: G01N,Y10T

Abstract:
1. A production method of a gas sensor having as a length and including a gas sensing element having a gas-exposed portion, a hollow housing having a first and a second end portion which are at opposite ends of the housing in a lengthwise direction of the gas sensor, holding the gas sensing element in the housing so as to arrange the gas-exposed portion outside the housing for exposure to a gas to be measured, a protective cover installed on the first end portion of the housing to cover the gas-exposed portion of the gas sensing element, leads connecting with the gas sensing element, extending from the second end portion of the housing in the lengthwise direction of the gas sensor for electrical communication with an external device, an insulator retaining therein the leads connecting with the gas sensing element, and a metallic cover aligned with the housing in the lengthwise direction of the gas sensor so as to have an overlap with the second end portion of the housing and holding the insulator therein, the overlap being an end of the metallic cover which faces an entire circumference of the second end portion of the housing in a direction perpendicular to the lengthwise direction of the gas sensor, said production method comprising the steps of: preparing an assembly of the housing and the metallic cover; rotating said assembly around a central axis thereof extending in the lengthwise direction of the gas sensor; keeping a rotational speed of said assembly at a given constant value; and emitting a laser beam to the overlap of the metallic cover with the second end portion of the housing in a direction perpendicular to the central axis of said assembly to weld the metallic cover to the housing.