Title:
SPARK PLUG
Document Type and Number:
Japanese Patent JP2018174034
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To provide a spark plug capable of increasing the degree of freedom of design at a portion of an insulator, the portion being present in the vicinity of the tip of a center electrode.SOLUTION: A spark plug includes a center electrode a part of which is surrounded by an insulator. A main metal fitting holds the insulator from an outer peripheral side, and a shelf part of the main metal fitting projects radially inward. The insulator includes: a first insulator including a through hole surrounding the center electrode such that the tip of the center electrode projects and a locking part locked to the shelf part from a tip side; and a second insulator which is disposed closer to a tip side than the locking part of the first insulator and the inner peripheral surface of which is partly joined to a part of the outer peripheral surface of the first insulator directly or via other member. The second insulator is screwed to the first insulator to be joined.SELECTED DRAWING: Figure 1
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Inventors:
USAMI KOHEI
YAMADA YUICHI
YAMADA YUICHI
Application Number:
JP2017069838A
Publication Date:
November 08, 2018
Filing Date:
March 31, 2017
Export Citation:
Assignee:
NGK SPARK PLUG CO
International Classes:
H01T13/20
Attorney, Agent or Firm:
Patent Service Corporation Shinmei Century