JP3148931B2 - Spark plug manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spark plug used in an internal combustion engine, and more particularly to a method for manufacturing a ground electrode.

[0002]

2. Description of the Related Art In recent years, as the performance of an internal combustion engine has been improved, the temperature of combustion gas generated in the combustion chamber of the internal combustion engine has become high. Since the ground electrode that performs spark discharge to ignite the gas is constantly exposed to the high-temperature combustion gas, the temperature tends to be high. As a result, the high-temperature ground electrode causes pre-ignition. In order to improve the thermal conductivity to the metal shell that is integrally joined, copper or nickel or other good heat conductive metal is sealed in the ground electrode, and the ground electrode itself has a composite structure. Things have been suggested.

[0003]

However, in the above-mentioned conventional device, a case where a copper-like rod material having good heat conductivity is sealed in a cup-shaped ground electrode made of nickel to form a ground electrode having a composite structure. Since the crimped part of each ground electrode manufactured by plastic working is joined to the metal shell by electric resistance welding, the number of working steps increases, so that the manufacturing workability decreases and the cost increases. There is.

[0004] Although a ground electrode having a composite structure is obtained by encapsulating a nickel material having good thermal conductivity in a ground electrode made of Inconel 600, the best particularly simple manufacturing method has not been elucidated.

Therefore, the present invention is intended to improve the above-mentioned drawbacks of the prior art, and aims to manufacture a ground electrode having a composite structure by a simple method.

[0006]

Therefore SUMMARY OF THE INVENTION The spark plug of the ground electrode which is joined integrally with the metal shell at a position opposing to the tip of the center electrode that will be held in the insulator tip is placed
A method for manufacturing a grounding electrode , wherein the ground electrode is formed by winding a sheet-shaped outer material around a cylindrical core material and then winding the sheet-shaped outer material.
On which a composite rod was welded seams and the core material of the sheet-like outer covering layer, while smaller diameter by to repeat the drawing process and the annealing process on the composite rod, the the alloy layer is formed on the joint interface between the core material and the sheet-like outer covering of the composite rod, then the diameter of the wire-like composite, so as to have a rounded rectangular shape in cross section four corners,
After forming with a roller or a die to obtain a molded material , this molded material is joined to the metal shell by electric resistance welding .
And formed by

[0007] Further, the ground electrode is made of a sheet-like outer material.
Winding , the above-mentioned sheet-like outer skin material formed by this winding
Weld the seam into a pipe shape
A cylindrical core material is inserted into the sheet-like outer material to form a composite round bar . The composite round bar is subjected to a wire drawing process and an annealing process.
By repeating the process, the diameter is reduced, and the composite round bar is assembled.
The bonding interface between the core material and the sheet
Forming a gold layer and then reducing the diameter of this wire-shaped composite
Roller so that it has roundness at the four corners of the rectangular cross section
-Or molding with a die to form a molding material
The material is joined to the metal shell by electric resistance welding.
It can be done.

[0008]

Since comprises a [action] of the above configuration, the grounding electrodes, after winding the sheet-shaped outer skin material in a cylindrical shape of the core material, this winding
Welded to the joint and the core of which is formed the sheet-like outer covering on which a composite round bar, while smaller diameter by to repeat the drawing process and the annealing process on the composite rod, the bonding interface between the core material and the sheet-like outer covering layer constituting the <br/> composite round bar to form an alloy layer, and then the diameter of the wire-like composite, rounded rectangular shape in cross section four corners By using a roller or a die to form a molded material so as to have the above, mass production can be performed easily and in large quantities.

[0009] The ground electrode may be made of a sheet-like outer material.
Winding , the above-mentioned sheet-like outer skin material formed by this winding
Weld the seam into a pipe shape
By inserting a cylindrical core material on which the composite rod with respect to sheet-like skin material, wire drawing step and annealing Engineering for this composite rod
By repeating the process, the diameter is reduced, and the composite round bar is assembled.
The bonding interface between the core material and the sheet
Forming a gold layer and then reducing the diameter of this wire-shaped composite
Roller so that it has roundness at the four corners of the rectangular cross section
Alternatively, the molding process can be further simplified by molding with a die or a die .

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. (1) A ground electrode (6) according to an embodiment of the present invention.
The spark plug includes a center electrode (3) held at a tip of an insulator (2) and a spark at the tip of the center electrode (3). A ground electrode (6) integrally joined to the metal shell (5) is arranged at a position facing the discharge portion (4).

The ground electrode (6) integrally joined to the metal shell (3) has a core material (7) made of a metal having good thermal conductivity such as pure nickel or pure iron. ) Coated with 95% by weight nickel alloy (S
i, Cr, Al, Mn, etc., at most 5% by weight).

Further, as shown in FIG. 2, the ground electrode (6) having the composite structure is provided with a sheet-like outer material (7) on a columnar core material (7) made of a metal having good thermal conductivity such as nickel. after winding the 8), after having welded seams and the core material of the sheet-shaped outer skin material (8) and (7) a composite rod (9), Shin against the composite rod (9) while smaller diameter by applying repeatedly a line process and annealing process, an alloy layer at the joint interface of the core and (7) the sheet-like outer covering layer (8) constituting the composite rod (9) (10 ) Is formed, and the wire-shaped composite material (11) having a reduced diameter is formed into a formed material (12) by using a roller or a die so as to have roundness at four corners having a rectangular cross section. Molding material (1
By electrical resistance welding the end faces of 2) on the end face of the metal shell (5), successively, moreover those formed by joining together.

Since the present invention has the above-described structure, a core material (7) made of pure nickel or the like having good thermal conductivity is sealed in a sheet-shaped outer material (8) made of a nickel alloy or the like. After a sheet-like outer material (8) is wound around a cylindrical core material (7), a ground electrode (6) having a composite structure of ) Is welded to form a composite round bar (9), and the composite round bar (9) is repeatedly subjected to a wire drawing step and an annealing step to reduce the diameter and constitute the composite round bar (9). By forming an alloy layer on the joint interface (10) between the core material (7) and the sheet-like outer material (8) to be formed into a wire-shaped composite material (11) having a reduced diameter,
A composite structure located at the tip (1) of the spark plug
The large number of ground electrodes (6) can be easily mass-produced.

Further, as shown in FIG. 3, the ground electrode
(6), the sheet-shaped outer skin material (8) wound in the winding
A pipe-shaped the sheet-like outer covering that is more form seams (8) and dissolved <br/> contact, cylindrical core member with respect to the sheet-like outer covering of the pipe-shaped (8) (7) inserted to after having a composite rod (9), drawing Engineering for this composite rod (9)
And the annealing step are repeated to reduce the diameter.
The core material (7) and the sheet constituting the composite round bar (9)
An alloy layer is formed at the joint interface with the outer shell material (8).
The reduced diameter wire-shaped composite material (11) is cross-sectionally elongated.
Rollers or dies so that the four corners of the shape are rounded
To form a molding material (12), and this molding material
(12) joined to metal shell (5) by electric resistance welding
The spark plug may be formed by
Wire-like composite that becomes the ground electrode (6) at the tip (1)
By manufacturing the material (11), the ground electrode (6)
Can be simplified.

[0015]

As described above, by manufacturing a ground electrode having a composite structure, unlike the conventional manufacturing method,
Since it is simple and can be mass-produced, it is used for an internal combustion engine with high performance in recent years, and has an excellent effect of being able to provide a low-cost spark plug with good heat dissipation. is there.

[Brief description of the drawings]

FIG. 1 is a partially enlarged sectional view of a spark plug tip portion according to an embodiment of the present invention.

FIG. 2 is a view showing a manufacturing process of a ground electrode according to an embodiment of the present invention.

FIG. 3 is an enlarged perspective view of a manufacturing process according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tip part of spark plug 2 Insulator 3 Center electrode 4 Spark discharge part 5 Metal shell 6 Ground electrode 7 Core material 8 Outer material 9 Composite round bar 10 Alloy layer 11 Wire-like composite material 12 Molding material 13 Pipe-like outer material

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01T 13/00-21/06 B21F 19/00

Claims (2)

(57) [Claims] To 1. A position opposing to the tip of the center electrode that will be held in the insulator tip, a method for producing a spark plug ground electrode which is joined integrally with the metal shell is disposed, before
The ground electrode is formed by winding a sheet-shaped outer material around a cylindrical core material, and then winding the sheet-shaped outer material formed by this winding .
On the joint and the core material was welded to a composite rod, as well as smaller diameter by to repeat the drawing process and the annealing process on the composite rod, the core constituting the composite rod Lumber and above
The junction interface between the serial sheet skin material to form an alloy layer, with
The wire-shaped composite material having a reduced diameter is formed into a molded material by using a roller or a die so as to have roundness at four corners having a rectangular cross section, and then the molded material is joined to a metal shell by electric resistance welding. It is formed by doing
Method of manufacturing a spark plug to be. 2. A tip of a center electrode held at a tip of an insulator.
The grounding electrode that is integrally joined to the metal shell
A method of manufacturing a spark plug in which poles are arranged,
Serial ground electrode is wound around a sheet-like outer skin material, to the wound
The seam of the sheet-shaped outer material thus formed is welded into a pipe shape, and a cylindrical core material is inserted into the pipe-shaped sheet-shaped outer material to form a composite round bar . Above, this composite
By repeating the wire drawing process and the annealing process on the round bar,
The core material and the core material constituting the composite round bar
An alloy layer is formed at the joint interface with the sheet-like outer material,
This reduced-diameter wire-shaped composite material is
Roll or die to make the corners round.
After forming into a molding material, this molding material is
It is characterized by being formed by joining by anti-welding
Method of manufacturing a spark plug.