Spark plug
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United States of America Patent
Stats
-
Mar 6, 2018
Issued Date -
N/A
app pub date -
Sep 22, 2016
filing date -
Sep 24, 2015
priority date (Note) -
In Force
status (Latency Note)
Importance
Abstract
A spark plug includes an insulator, a center electrode, a metallic shell, and a ground electrode. The insulator contains not less than 90.0 mass % and not greater than 98.1 mass % of Al2O3 with respect to a total mass of elements, as reduced to oxides, contained in the insulator, and has a porosity not greater than 5%. Assuming that a porosity of the insulator after a heat treatment is B, a difference (B−A) of the porosities before and after the heat treatment is not greater than 3.5%. In the heat treatment, the insulator is placed in a furnace, and a temperature in the furnace is increased from a room temperature to 1400° C. at a temperature increase rate of 7° C./min and is held at 1400° C. for 30 minutes, and thereafter, the temperature is decreased from 1400° C. to 400° C. at a temperature decrease rate of 10° C. or less per 5 minutes and is decreased to the room temperature.
First Claim
Family
International Classification(s)
Cited Art Landscape
Patent Citation Ranking
- 2 Citation Count
- H01T Class
- 27.40 % this patent is cited more than
- 7 Age
Maintenance Fees
| Fee | Large entity fee | small entity fee | micro entity fee | due date |
|---|---|---|---|---|
| 7.5 Year Payment | $3600.00 | $1800.00 | $900.00 | Sep 6, 2025 |
| 11.5 Year Payment | $7400.00 | $3700.00 | $1850.00 | Sep 6, 2029 |
