Gas sensor production method and gas sensor

A method of producing a gas sensor having a sensor element extending in an axial direction and having a front end side to face a measured gas, a metallic housing holding therein the sensor element, a tubular metallic member provided to a rear end side of the metallic housing, at least one lead wire extending from an inside to an outside of the tubular metallic member and having a conductor wire electrically connected to the sensor element and an insulating film covering the conductor wire, and an elastic seal member having a lead wire insertion hole into which the lead wire is inserted, the method comprising:

• a disposition step of disposing the elastic seal member inside the tubular metallic member so that the a portion of the elastic seal member protrudes outward from a rear end of the tubular metallic member;
• and
• a crimping step of crimping at least a portion of the tubular metallic member radially inward and thereby compressively deforming the elastic seal member;
• wherein the crimping step is performed under a condition where a space between the rear end of the tubular metallic member and the outer circumferential surface of the elastic seal member corresponding in position to the rear end of the tubular metallic member is larger than a space between an inner circumferential surface of a portion to be crimped of the tubular metallic member and the outer circumferential surface of the elastic seal member corresponding in position to the portion to be crimped of the tubular metallic member.

A gas sensor comprising:

• a sensor element extending in an axial direction and having a front end side to face a measured gas;
• a metallic housing holding therein the sensor element;
• a tubular metallic member provided to a rear end side of the metallic housing;
• at least one lead wire extending from an inside to an outside of the tubular metallic member and having a conductor wire electrically connected to the sensor element and an insulating film covering the conductor wire;
• and
• an elastic seal member having a lead wire insertion hole into which the lead wire is inserted, wherein a space is provided between the rear end of the tubular metallic member and the outer circumferential surface of the elastic seal member.