SPARK PLUG AND METHOD OF MAKING THE SAME
First Claim
1. A spark plug comprising:
- a center electrode;
an insulator disposed around the center electrode;
a metal shell disposed around the insulator;
a ground electrode disposed in opposition to the center electrode so as to form a spark discharge gap; and
a sealing-material layer comprising a sealing material, wherein the sealing material comprises talc, and the sealing-material is filled in a space between the inner face of the metal shell and the outer face of the insulator, so as to seal the space, wherein the sealing material has a filling density of 1.5 g/cm3 to 3.0 g/cm3.
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Accused Products
Abstract
A spark plug comprises: a center electrode (3); an insulator (2) provided around the center electrode (3); a metal shell (1)provided around the insulator (2); a ground electrode (4) disposed in opposition to the center electrode (3) so as to form a spark discharge gap; and a sealing-material layer (61) comprising a sealing material, wherein the sealing material comprises talc, and the sealing material is filled in a space between the inner face of the metal shell (1) and the outer face of the insulator (2), so as to seal the space, wherein the sealing material has a filling density of 1.5 g/cm3 to 3.0 g/cm3, or the sealing-material layer (61) comprises at least one of an inorganic material and a silicone binder in an amount of 2 to 7 wt %.
10 Citations
10 Claims
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1. A spark plug comprising:
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a center electrode;
an insulator disposed around the center electrode;
a metal shell disposed around the insulator;
a ground electrode disposed in opposition to the center electrode so as to form a spark discharge gap; and
a sealing-material layer comprising a sealing material, wherein the sealing material comprises talc, and the sealing-material is filled in a space between the inner face of the metal shell and the outer face of the insulator, so as to seal the space, wherein the sealing material has a filling density of 1.5 g/cm3 to 3.0 g/cm3. - View Dependent Claims (2, 3, 4, 5, 6, 8)
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7. A spark plug comprising:
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a center electrode;
an insulator disposed around the center electrode;
a metal shell provided around the insulator;
a ground electrode disposed in opposition to the center electrode so as to form a spark discharge gap; and
a sealing-material layer comprising a sealing material, wherein the sealing material comprises talc, and the sealing material is filled in a space between the inner face of the metal shell and the outer face of the insulator, so as to seal the space, wherein the sealing-material layer comprises at least one of an inorganic material and a silicone binder in an amount of 2 to 7 wt %.
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9. A method of making a spark plug, the spark plug comprising:
- a center electrode;
an insulator provided around the center electrode;
a metal shell provided around the insulator;
a ground electrode disposed in opposition to the center electrode so as to form a spark discharge gap; and
a sealing-material layer comprising a sealing material, wherein the sealing material comprises talc, and the sealing material is filled in a space between the inner face of the metal shell and the outer face of the insulator, so as to seal the space, which comprises;
a filling process of forming a powder-filled layer by i) locating the insulator inside of the metal shell and ii) filling powder of sealing material comprising talc in the space between the metal shell and the insulator;
a compression process of compressing the powder-filled layer in an axial direction of the metal shell so as to form the sealing-material layer; and
a forming process of, prior to the filling process, forming the filled powder in a ring shape corresponding to said space, so as to form a formed body, wherein, in the filling process, the formed body of the filled powder is located in said space, and in the compression process, the formed body as the powder filled layer is compressed at a higher pressure than that in the forming process, so that the sealing-material layer is formed having a filling density of 1.5 g/cm3 to 3.0 g/cm3 . - View Dependent Claims (10)
- a center electrode;
Specification