Assembly of spark plug and engine main body
AssigneeDenso Corporation
InventorNobuo Abe
Life of this patent
Estimating the term…
Abstract
An assembly includes an engine main body, a spark plug and a gasket. The spark plug is mounted to the engine main body by tightening a male-threaded portion of the spark plug into a female-threaded portion of the engine main body with the gasket elastically deformed between a seat surface of the engine main body and a seating surface of the spark plug. The gasket is made of a metallic material whose yield stress or 0.2% proof stress is not lower than 200 N/mm2. The gasket has first and second contact surfaces respectively in contact with the seating surface of the spark plug and the seat surface of the engine main body. The first and second contact surfaces of the gasket are each formed as a part of a curved surface that has a convex shape, and are offset from each other in a radial direction of the spark plug.
Claims6
An assembly comprising:
- a main body of an engine having a spark plug-mounting bore formed therein, the main body also having a female-threaded portion that is formed in an inner surface of the spark plug-mounting bore and a seat surface that is formed around an open end of the spark plug-mounting bore;
- a spark plug having a longitudinal axis and a male-threaded portion that is formed on an outer surface of the spark plug so as to threadedly engage with the female-threaded portion of the main body of the engine, the spark plug also having a seating surface that is formed on one side of the male-threaded portion so as to face the seat surface of the main body of the engine;
- and
- a substantially annular gasket interposed between the seat surface of the main body of the engine and the seating surface of the spark plug so as to hermetically seal therebetween,
- wherein
- the spark plug is mounted to the main body of the engine by tightening the male-threaded portion of the spark plug into the female-threaded portion of the main body with the gasket elastically deformed between the seat surface of the main body of the engine and the seating surface of the spark plug,
- the gasket is made of a metallic material whose yield stress or 0.2% proof stress is higher than or equal to 200 N/mm2,
- the gasket has a first contact surface that is in contact with the seating surface of the spark plug and a second contact surface that is in contact with the seat surface of the main body of the engine,
- the first and second contact surfaces of the gasket are each formed as a part of a curved surface that has a convex shape on a cross section of the gasket, the cross section being taken so as to lie in the same plane as the longitudinal axis of the spark plug,
- the first and second contact surfaces of the gasket are offset from each other in a radial direction of the spark plug, and
- the amount of radial offset between the first and second contact surfaces of the gasket is greater than or equal to 0.6 mm.
Dependencies are inferred from the claim text.