Spark plug
AssigneeNgk Spark Plug Co., Ltd.
InventorYasushi SAKAKURA
Life of this patent
Estimating the term…
Abstract
A spark plug including: a center electrode; an insulator; a metal shell; a ground electrode; and an electrode chip. The electrode chip is joined to the ground electrode in a state in which the electrode chip is engaged in a recess portion formed in the ground electrode. The electrode chip is formed by previously welding a chip body portion containing a noble metal and a chip holding portion containing Ni before the electrode chip is joined to the ground electrode. A first molten bond is formed by welding the chip body portion and the chip holding portion. The first molten bond is placed in the recess portion so as not to be exposed to an outside environment in a state in which the electrode chip is engaged in the recess portion and joined to the ground electrode.
Claims7
A spark plug comprising:
- a center electrode;
- an insulator having an axial hole extending in an axial direction and holding the center electrode in the axial hole;
- a metal shell which holds the insulator and surrounds a radial periphery of the insulator in a circumferential direction;
- a ground electrode comprising a first end portion joined to the metal shell and a second end portion, the ground electrode being bent such that the second end portion faces a leading end portion of the center electrode;
- and
- an electrode chip joined to the ground electrode in a state in which the electrode chip is engaged in a recess portion formed in the second end portion of the ground electrode at a position opposing the leading end portion of the center electrode,
- wherein the electrode chip is formed by previously welding a chip body portion formed of noble metal or an alloy containing a noble metal as a main component and a chip holding portion formed of Ni or an alloy containing Ni as a main component prior to joining the electrode chip to the ground electrode,
- wherein a first molten bond is formed by welding the chip body portion and the chip holding portion, and
- wherein the first molten bond is placed in the recess portion so as not to be exposed to an outside environment, in a state in which the electrode chip is engaged in the recess portion and joined to the ground electrode.
A spark plug comprising:
- a center electrode;
- an insulator having an axial hole extending in an axial direction and holding the center electrode in the axial hole;
- a metal shell which holds the insulator by surrounding a radial periphery of the insulator in a circumferential direction;
- a ground electrode comprising a first end portion joined to the metal shell and a second end portion having a recess portion formed at a position facing a leading end portion of the center electrode;
- and
- an electrode chip welded to the second end portion of the ground electrode and comprising a chip body portion containing noble metal as a main component and a chip holding portion containing Ni as a main component, the chip body portion being joined to the chip holding portion via a first molten bond in which the chip body portion and the chip holding portion are fused,
- wherein the electrode chip is fitted to the recess portion such that the first molten bond of the electrode chip is not exposed from the recess portion.
Dependencies are inferred from the claim text.