Patent ID: 6857316

Claim:
A gas sensor comprising a sensor element for detecting a specific gas component, a housing which contains said sensor element therein and has a sealing surface which forms a sealing section together with an installation section at the front in a direction in which said sensor element in inserted, and a rotating member which has a thread section which is formed outside said rotating member and is to be screwed into the installation section and can be rotated concentrically with respect to a central axis of said housing; wherein when said gas sensor is installed in the installation section by screwing said rotating member into the installation section, a release torque of said rotating member at 850° C. (1123 K) is 9 N·m or more; and wherein an estimated value X 3 of a gap formed between said sealing surface of said housing and a sealing surface of the installation section at 850° C. (1123 K), that is calculated according to the following equation, is 31 μm or less: X 3 (μm)={( L 1 ×α 1 )−( L 4 ×α 4 )−( L 5 ×α 5 )}×1123; wherein X 3 represents an estimated value (μm) of the gap, L 1 represents a length (μm) from the sealing surface of the installation section to a top end of the installation section, L 4 represents a length (μm) from a bottom end to a top end of said thread section, L 5 represents a length (μm) from said sealing surface of said housing to the bottom end of said thread section, α 1 represents a coefficient of thermal expansion (×10 −6 /° C.) of the installation section, α 4 represents a coefficient of thermal expansion (×10 −6 /° C.) of said rotating member, and α 5 represents a coefficient of thermal expansion (×10 −6 /° C.) of said housing.