JP3196352B2 - Method of manufacturing spark plug for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a spark plug for an internal combustion engine in which a composite tip comprising a discharge layer and a relaxation layer is welded to a discharge portion of an electrode material.

[0002]

2. Description of the Related Art Pt or Pt is used in engines of automobiles and the like.
A spark plug in which a noble metal such as a t-alloy is welded to the discharge part is mounted. Since the spark plug has the noble metal disposed in the most exhausted discharge portion, it can be used for a long time without maintenance.

On the other hand, from the standpoint of environmental protection such as fuel saving and emission control, the temperature in the combustion chamber of the engine tends to increase more and more due to the trend toward higher compression ratios and lean burn. Therefore, in the discharge part of the spark plug, thermal stress due to a difference in linear expansion coefficient between the noble metal and the electrode material of the discharge part is large.

Therefore, as disclosed in Japanese Patent Publication No. 2203/33, a composite layer is formed by joining a relief layer having a linear expansion coefficient between the noble metal and the electrode material to the discharge layer made of the noble metal. Then, it has been proposed to weld the relaxation layer side of the composite tip to the discharge portion of the electrode material.
The relaxation layer is a layer for relaxing thermal stress between the noble metal and the electrode material.

[0005]

When the composite chip is welded to a discharge portion, it is necessary to distinguish between the discharge layer side and the relaxation layer side of the composite chip. However, the thickness of the conventional composite chip is about 0.3 to 0.7 mm. In addition, the two layers are often of substantially the same thickness. Therefore, it is difficult to distinguish between the discharge layer side and the relaxation layer side. Therefore, it has been proposed to weld a composite chip having a different discharge layer side end dimension and a different relaxation layer side end dimension, or a composite chip having one of its bottom surfaces colored or the like, to a discharge portion of a spark plug. (JP-A-60-262374).

[0006] However, it is very difficult to provide a difference in end dimensions in the composite chip punching step. Therefore,
In addition to the above-described punching step, a step for making a difference in the end size is added. For this reason, there is a possibility that the difference of the end dimensions may be erroneously attached upside down, which is uncertain.

[0007] In addition, the number of new steps increases as described above, resulting in an increase in cost. In addition, when coloring or the like is performed on one of the two surfaces, the number of new steps increases, and the cost increases. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide a method of manufacturing a spark plug for an internal combustion engine, which can reliably identify the front and back of a composite chip and is inexpensive.

[0008]

The present invention comprises an insulator, a center electrode held by the insulator, a housing fixed to the outer periphery of the insulator, and a ground electrode provided on the housing and facing the center electrode. A spark plug for an internal combustion engine, wherein a composite tip formed by previously joining a discharge layer and a relaxation layer is provided in a discharge portion of at least one of the center electrode and the ground electrode. , Where the discharge layer and the relaxation layer are joined.
By punching plywood, the composite chip
A first step of manufacturing the composite chip in which an identification mark made of an arc-shaped sag is marked on a peripheral edge of the composite chip; and a step of identifying the identification mark in the composite chip, arranging a relief layer side on the discharge section and welding. A method for producing a spark plug for an internal combustion engine, comprising performing two steps.

In the present invention, the identification mark is a composite mark.
This is a sag in which the periphery of the chip is formed in an arc shape. This dripping
Punches a composite plate in which the discharge layer and the relaxation layer are joined
It is formed by this. The upper SL of sagging, the corners slightly refers to shape without the arc (see FIG. 2).

The width A of the sag is preferably 0.05 to 0.4 mm (see FIG. 2). If it is less than 0.05 mm, the sag may not be able to be reliably identified. 0.
If it exceeds 4 mm, there is a possibility that the discharge performance of the composite chip or the welding of the composite chip to the discharge portion may be hindered. In the case where a mark or a knurl is formed on one surface on which the sag is formed, it is preferable that the mark or the knurl is formed such that the sag is identifiable.

The height B of the sag is 0.05 to 0.3 m.
m is preferable. If it is less than 0.05 mm, the sag may not be able to be reliably identified. If the thickness exceeds 0.3 mm, there is a possibility that the discharge performance of the composite chip or the welding of the composite chip to the discharge portion may be hindered. In addition, in addition to sagging as an identification mark,
It is also possible to form stamps and knurls on the composite chip.
Wear. In addition, a composite chip that has already joined the discharge layer and the relaxation layer
Drip and stamp or drip and knurl on one side
Can also be formed. Drip as the above identification mark
, Stamp, and knurl are the discharge surface of the discharge layer of the composite chip.
Is preferably marked. As a result, the composite chip
Welding between the relief layer and the discharge part can be reliably performed. Up
The above-mentioned composite plate material is marked with the identification mark from the shape of the composite chip.
Preferably formed when punching with a small punch
No. This allows the composite chip to be punched out and
A sag can be formed at the edge.

The above-mentioned marking is formed on an arbitrary portion on one side of the composite chip. The shape of the engraving is conical, triangular pyramid,
It has a quadrangular pyramid shape, a polygonal pyramid shape, a single groove shape, or the like.
It is preferable that the opening width C of the stamp is 0.1 to 0.6 mm (see FIGS. 6 to 11). If it is less than 0.1 mm, it is difficult to identify the inscription. If the thickness exceeds 0.6 mm, there is a possibility that the discharge performance of the composite chip or the welding of the composite chip to the discharge portion may be hindered.

The depth D of the imprint is not less than 0.02 mm and is 1 / th of the thickness of the discharge layer or the relaxation layer on which the imprint is imprinted.
It is preferably 2 or less (see FIGS. 6, 7, and 11). If the depth D is less than 0.02 mm, it is difficult to identify the inscription. Further, if the thickness exceeds 1/2 of the thickness of the discharge layer or the relief layer on which the mark is marked, there is a possibility that the discharge performance of the composite chip or the welding of the composite chip to the discharge portion may be hindered.

The knurls have a shape such as a flat or a twill, and are formed on a part of the composite chip or on one entire surface. The direction of the knurls may be perpendicular, parallel, or oblique to the transport direction of the roll with the knurls cut. The groove width E of the knurl is preferably 0.1 to 0.3 mm (see FIGS. 14 and 15). 0.1mm
If it is less than knurl, it is difficult to identify the knurled eyes. If the thickness exceeds 0.3 mm, there is a possibility that the discharge performance of the composite chip or the welding of the composite chip to the discharge portion may be hindered.

It is preferable that the depth F of the knurl is not less than 0.02 mm and not more than １ ／ of the thickness of the discharge layer or the relaxation layer on which the knurl is marked (see FIG. 14). If the depth F is less than 0.02 mm, it is difficult to identify the inscription. If the knurled mark exceeds half the thickness of the discharge layer or the relaxation layer,
This may hinder the discharge performance of the composite tip or the welding of the composite tip to the discharge part.

[0016] The stamp or knurl is used to insert the composite chip.
Can be formed for the composite board to be formed
You. Also, for composite chips punched from composite plate
It can also be formed .

The double plywood is preferably rolled by rollers or the like. Thereby, the plate material for the discharge layer and the plate material for the relaxation layer are firmly joined. In addition, the thickness of the composite plate can be freely adjusted. In the above-mentioned rolling step, knurls can be formed together with rolling by using a knurling tool or the like.

[0018] In identifies sagging as the identification mark, for example Mochiiruko the vibrating Borufu Iruda
Can be. The vibrating ball filter has a groove-shaped through hole.
If the periphery of the composite chip has a pin angle, the composite chip
The stop is stopped, and in case of dripping, it is passed.
If engraved or knurled holes are formed,
Identification using an image recognition device or the like that recognizes by image processing
be able to. When welding the composite tip to the discharge part,
This is performed by resistance welding or the like.

[0019]

In the present invention, the periphery of the composite chip is
Since the identification mark made of arc-shaped sag is formed in the portion, the discharge layer side and the relaxation layer side of the composite chip can be easily and reliably identified. In addition, as the identification mark
Sagging should be formed during the punching process of composite chips
Requires the process of creating identification marks
Nothing. Therefore, according to the present invention, the identification mark can be easily formed without increasing the number of steps. ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the spark plug for internal combustion engines which can identify the front and back of a composite chip reliably can be provided.

[0020]

Embodiment 1 An embodiment according to the present invention will be described with reference to FIGS. The spark plug 2 for an internal combustion engine of this embodiment is shown in FIG.
As shown in FIG. 4, a spark is interposed between the insulator 20, the center electrode 4 held by the insulator 20, a housing 25 fixed to the outer periphery of the insulator 20, and the center electrode 4 provided on the housing 25. It comprises a ground electrode 3 provided with a discharge gap 5 and opposed to each other.

Discharge portions 30 and 40 are provided at the tips of the ground electrode 3 and the center electrode 4. As shown in FIG.
As shown in FIG. 4, the composite chip 1 in which the discharge layer 11 and the relaxation layer 19 are joined and the identification mark 100 is marked is welded. The composite chip 1 has a diameter of 1 mm and a thickness of 0.1 mm.
5 mm.

The discharge layer 11 is made of an 80% Pt-20% Ir alloy having a thickness of 0.35 mm and a coefficient of thermal expansion of 9 × 10 ⁻⁶ / ° C., and the relaxation layer 19 has a coefficient of thermal expansion of 0.15 mm and a thickness of 0.15 mm.
It is made of 80% Pt-20% Ni alloy at 2 × 10 ⁻⁶ / ° C. The ground electrode 3 and the center electrode 4 have a thermal expansion coefficient of 15 × 1.
It is made of an electrode material using a Ni-based heat-resistant alloy of 0 ^-6 / ° C.

In the discharge section 30, the composite chip 1 is provided.
The discharge section 40 is provided with a discharge layer 11. A gap 5 for spark discharge is provided between the discharge layer 11 and the discharge layer 11 side of the composite chip 1. The ground electrode 3 extends from the housing 25. Further, inside the center electrode 4, in order to improve the thermal conductivity of the center electrode 4,
A Cu material 42 is enclosed.

Next, a method of manufacturing the spark plug for an internal combustion engine will be described. First, in the first step, as shown in FIG. 2, a composite chip 1 in which the discharge layer 11 and the relaxation layer 19 are joined and the identification mark 100 is marked is produced. The identification mark 100 is an arc-shaped sag formed on the periphery of the discharge layer 11. The width A of this sag is 0.3m
m and height B are 0.1 mm. That is, as shown in FIG. 1, the discharge layer plate 110 and the relaxation layer plate 190 are joined to obtain the composite plate 10. Next, the composite plate 10 is rolled using a roller.

Next, the composite plate material 10 is placed on the die 71 having an opening 710 having the same shape as the shape of the composite chip to be obtained. A punch 91 having a punch surface 910 smaller by the clearance 5 is arranged. Then, the punch 91 presses the relaxation layer plate 190 side of the composite plate 10.
Thereby, the composite chip 1 is punched,
As shown in FIG. 2, an arc-shaped identification mark (sag) 100 is formed on the periphery of the discharge layer 11. Clearance 5 above
Sets the width A and the height B of the sag.

Next, in the second step, the identification mark 100 of the composite chip 1 is identified by a vibrating ball filter (manufactured by Shinko Electric Co., Ltd.), and the relief layer 19 side is discharged to the discharge section 30.
And welded. The vibrating ball filter has a groove-shaped passage, stops the composite chip when the peripheral edge of the composite chip 1 has a pin angle, and allows the composite chip to pass when the peripheral edge of the composite chip 1 sags. When the composite chip 1 is welded to the discharge unit 30, resistance welding is performed.

Next, the operation and effect of this embodiment will be described.
In this example, since the identification mark 100 is formed on the discharge layer 11 side of the composite chip 1, the discharge layer 11 side and the relaxation layer 19 side of the composite chip 1 can be easily and reliably identified. Further, since the identification mark 100 can be formed continuously to the formation process of the composite chip 1, it can be easily formed without increasing the number of steps.

[0028]Reference Example 1  In the method of manufacturing the spark plug of this embodiment, FIGS.
As shown in 6,At the center of the discharge surface 111 of the discharge layer 11,
It has a conical stamp 101.

Next, a method of manufacturing the spark plug of the present embodiment will be described. First, in the first step, the discharge layer 11
And with formed by bonding the relaxation layer 19, to produce a composite chip 1 mark engraved 1 01. The opening width C of the inscription 101 is 0.3 mm, and the depth D is 0.05 mm.

That is, as shown in FIG.
The composite sheet 10 is obtained by joining the sheet 10 and the relaxation layer sheet 190 and rolling them. Next, the tip 92 having the same shape as the engraving
The marking punch 92 having 0 is disposed on the discharge layer plate 110 side, and the support base 72 is disposed on the relaxation layer plate 190 side. Then, while supporting the composite sheet 10 in the support base 72, to press the discharge layer sheet 110 side of the composite sheet 10 by stamping punch 92, marks the marking 1 01.

Next, a punch 931 having a punch surface 930 having the same shape as the shape of the composite chip to be obtained is placed on the relaxation layer plate 190 side, and a die 71 having an opening 710 having the same shape as the punch surface 930 is placed. They are arranged on the discharge layer plate 110 side, respectively. Then, the punch 93 presses the relaxation layer plate 190 side of the composite plate 10. This gives
The composite plate 10 is composed of a discharge layer 11 and a relaxation layer 19,
The composite chip 1 with the stamp 101 is punched. The stamp 92 and the punch 93 are driven by a single press. After the composite chip 1 is punched, the composite plate 10 is sequentially fed, and the next composite chip is sequentially punched.

Next, in a second step, the imprint 101 on the composite chip 1 is identified by an image recognition device, and the relief layer 19 side is disposed on the discharge part 30 side and welded (see FIG. 4). Others are the same as the first embodiment. In this embodiment, the same effect as in the first embodiment can be obtained.

[0033]Reference Example 2  In the manufacture of this example, as shown in FIG.Stamp102
Is the marking of the single groove. This stamp102The opening width C of
0.2 mm and its depth D is 0.05 mm.
OthersReference Example 1Is the same as In this example,three
Case 1The same effect as described above can be obtained.

[0034]Reference Example 3  In this example, as shown in FIG.Stamp103 is three
It is a pyramid-shaped stamp. This stamp103The opening width C of
0.3 mm and its depth D is 0.05 mm.
OthersReference Example 1Is the same as In this example,three
Case 1The same effect as described above can be obtained.

[0035]Reference example 4  In this example, as shown in FIG.Stamp104 is four
It is a pyramid-shaped stamp. This stamp104The opening width C of
0.2 mm and its depth D is 0.05 mm.
OthersReference Example 1Is the same as In this example,three
Case 1The same effect as described above can be obtained.

[0036]Reference example 5  In this example, as shown in FIG.Stamp105 is
It is a hexagonal pyramid shaped stamp. This stamp105The opening width C of
0.3 mm and its depth D is 0.05 mm.
OthersReference Example 1Is the same as In this example,three
Case 1The same effect as described above can be obtained.

Example2  FIGS. 11A and 11B show the composite chip 1 of this example.
As shown in the figure, the width A and the height marked on the periphery of the discharge layer 11 are shown.
Mark 100, which is an arc-shaped sag, and discharge surface 1
11 has a conical shape with an opening width C and a depth D marked at the center.
Stamp101 is provided.

In forming the engraving 101, first, as in Reference Example 1 , the engraving is formed on the discharge layer plate material of the composite plate material. A sag is formed on the plate material. Others are the same as the first embodiment. Also in this example, the first embodiment
Is the same as

[0039]Reference Example 6  In the manufacturing method of this example, as shown in FIG.composite
A flat knurl over the entire discharge surface 111 of the chip 1
Forming an eye 106. This knurled eye106Groove
The width E is 0.2 mm and the depth F is 0.05 mm
is there.

A method for manufacturing the spark plug of this embodiment will be described. First, a composite plate 10 is obtained in the same manner as in Reference Example 1, and then the composite plate 10 is rolled. In rolling, as shown in FIG. 12, a roller 69 having a smooth surface is used.
Are disposed on the side of the relaxation layer plate 190, and the rotary roller type knurling tool 61 is disposed on the side of the discharge layer plate 110. On the surface of the knurling tool 61, irregularities having the same shape as the knurled eyes are formed. Then, by rotating the roller 69 and the knurling tool 61, the composite plate material 10 is sequentially fed, and a knurl is marked on the discharge layer plate material 110. The knurls are perpendicular, parallel, or oblique to the roll transfer direction.

Next, as shown in FIG. 13, a punch 931 having a punch surface 930 having the same shape as the shape of the composite chip to be obtained is placed on the relaxation layer plate material 190 side, and the punch surface 9
A die 71 having an opening 710 having the same shape as 30 is arranged on the discharge layer plate 110 side. Then, the punch 93 presses the relaxation layer plate 190 side of the composite plate 10. As a result, as shown in FIG.
0 consists discharge layer 11 and the relaxing layer 19. knurled
The composite chip 1 marked with the eye 106 is punched. In this embodiment, the same effect as in the first embodiment can be obtained.

[0042]Reference Example 7  In this example, as shown in FIG.Knurled eyes1
07 is,Groove width E0. With a 2mm twill-shaped knurled eye
is there. OthersReference Example 6Is the same as In this example
Also,Reference Example 6The same effect as described above can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a manufacturing method according to a first embodiment.

FIG. 2 is a cross-sectional view of the composite chip according to the first embodiment.

FIG. 3 is a partial cross-sectional side view of the spark plug for an internal combustion engine according to the first embodiment.

FIG. 4 is an enlarged sectional view of a main part of the spark plug for an internal combustion engine according to the first embodiment.

FIG. 5 is an explanatory view showing the manufacturing method of Reference Example 1 .

FIG. 6 is a cross-sectional view and a rear view of the composite chip of Reference Example 1 .

FIG. 7 is a cross-sectional view and a rear view of the composite chip of Reference Example 2 .

FIG. 8 is a back view of the composite chip of Reference Example 3 ;

FIG. 9 is a back view of the composite chip of Reference Example 4 .

FIG. 10 is a back view of the composite chip of Reference Example 5 .

FIGS. 11A and 11B are a cross-sectional view and a rear view of the composite chip according to the second embodiment. FIGS.

FIG. 12 is an explanatory view showing a manufacturing method of Reference Example 6 .

FIG. 13 is an explanatory view following FIG. 12 showing the manufacturing method.

FIG. 14 is a cross-sectional view and a rear view of the composite chip of Reference Example 6 .

FIG. 15 is a back view of the composite chip of Reference Example 7 .

[Explanation of symbols]

1. . . Composite chip, 10. . . Composite board, 100. . . Identification mark, 101 to 105. . . Engraving, 106 , 107. . . Knurl eyes , 11. . . Discharge layer, 111. . . Discharge surface, 19. . . Relaxation layer, 2. . . Spark plugs for internal combustion engines, 20. . . Insulator, 25. . . Housing, 3. . . Ground electrode, 30, 40. . . Discharge section, 4. . . Center electrode, 61. . . Knurling tools, 91, 93. . . Punch, 92. . . Engraving punch,

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-60-262374 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01T 13/00-21/06

Claims (4)

(57) [Claims] An insulator, a center electrode held by the insulator, a housing fixed to an outer periphery of the insulator, a ground electrode provided on the housing and opposed to the center electrode, and A method for manufacturing a spark plug for an internal combustion engine, comprising: providing a composite tip formed by previously bonding a discharge layer and a relaxation layer to a discharge portion of at least one electrode material of an electrode or a ground electrode; Hit the composite plate with the above-mentioned relaxation layer
By pulling out, the arc on the periphery of the composite chip
A first step of fabricating the composite chip marked with an identification mark made of a sag, and a second step of identifying the identification mark in the composite chip, arranging the relief layer side on the discharge portion and welding. A method for producing a spark plug for an internal combustion engine. 2. The method according to claim 1, wherein the identification mark is
A method of manufacturing a spark plug for an internal combustion engine, wherein the composite plate is formed when punching the composite plate with a punch smaller than the shape of the composite chip. 3. The method of claim 1, on said identification mark
A method of manufacturing a spark plug for an internal combustion engine , wherein a width of the sag is 0.05 to 0.4 mm . 4. The method according to claim 1, wherein:
The sagging height of the identification mark is 0.05 to 0.3.
mm . A method for producing a spark plug for an internal combustion engine.