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(11) | EP 2 224 560 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Insulating member for spark plug and method of manufacturing the same, and spark plug for internal combustion engine |
| (57) A method of manufacturing an insulating member 2 for a spark plug, the insulating
member 2 including an axial hole 4 extending in an axial direction, in which a center
electrode 5 is held at a front end side of the axial hole and a terminal 6, e.g. a
metal terminal, is held at a rear end side of the axial hole. The method includes:
a pressurized forming step of compressing raw powder PM to form a molding CP1 having
a hole portion HL, of which a rear end side is opened and a front end side is closed;
a support pin inserting step of inserting a rod-shaped support pin 61 into the hole
portion 112 from the rear end side of the molding; and a grinding step of grinding
an outer circumferential surface of the molding CP1 inserted with the support pin
61 to form an unfired insulating member IP having a shape of the insulating member
2, wherein after the pressurized forming step and before the grinding step, a front
end removing step of cutting a front end portion of the molding or grinding the front
end portion in an axial direction to penetrate the hole portion is included.
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