Patent ID: 6796175
Filing Date: 2004-09-28
Classification: G01N,Y02A

Abstract:
A gas sensor comprising a sensor element, which functions to detect a specific gas component, a housing containing said sensor element therein and having a sealing surface, a thread section which is adapted to be screwed into an installation section, and a sealing section formed between said sealing surface of said housing and a sealing surface of the installation section at a position deeper than said thread section in a direction in which said sensor element is inserted;wherein when said housing is screwed into the installation section, a release torque of said housing at 850Â° C. (1123 K) is 9 NÂ·m or more; and wherein an estimated value X1 of a gap formed between said sealing surface of said housing and the sealing surface of the installation section at 850Â° C. (1323 K), that is calculated according to the following equation, is 31 &mgr;m or less: X1(&mgr;m)={(L1Ã—&agr;1)âˆ’(L2Ã—&agr;2)}Ã—1123; wherein X1 represents an estimated value (&mgr;m) of the gap, L1 represents a length (&mgr;m) from the sealing surface of the installation section to a top end of the installation section, L2 represents a length (&mgr;m) from said sealing surface of said housing to a top end of said thread section, &agr;1 represents a coefficient of thermal expansion (Ã—10âˆ’6/Â° C.) of the installation section, and &agr;2 represents a coefficient of thermal expansion (Ã—10âˆ’6/Â° C.) of said housing.