JPS60262374A - Method of producing spark plug for internal combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of Introduction 1) The present invention relates to a method of manufacturing a spark plug for an internal combustion engine,
In particular, the present invention relates to a method for manufacturing mebark plugs in which a depth is provided for a discharge layer and a stress relaxation layer made of +1 metal in order to improve durability in the ignition zone.

(Conventional technology)The conventional internal combustion (interstage spark plug is shown in Figure 9)
- As shown in the main part, a v1 metal tip 2 is installed at the firing part of the center electrode 1 and the ground electrode 3.

This precious metal depth may be an alloy of platinum and noridium, an alloy of platinum and tungsten, or an alloy of platinum and iridium.
The linear expansion coefficient is 8 to 9 x 10-6/°C. On the other hand, the central type to which this chip is bonded? The base material of 4!1 is a nickel-based heat-resistant alloy, and the linear expansion coefficient of C is 13 to 1.
4. Since X 10-6/"C, alloys with a difference in linear expansion coefficient of approximately 5 x 10-6/"C are joined at the bonding interface 4 between the depth 2 and the base metal.Spark plug is exposed to a harsh environment in which high-temperature and low-temperature melts are repeated under various operating conditions such as high load or low load, so thermal stress is repeatedly applied to the bonding interface 4 due to the difference in linear expansion coefficient and the repetition of cold and hot temperatures. fi #i as shown in Figs. 5 and 6 occurs at or near the bonding interface.
Crack 5a and/or oxidation ff4 eclipse 5b occurs, and negative metal depth 2 quickly becomes 1! IJ had the drawback of falling off. The spark surface (1-) is 3 to 7 mm Pi! This defect is particularly noticeable in the highly protruding shape (FIG. 10).

In order to improve this drawback of the conventional spark plug, the applicant has developed a spark plug tip as shown in Figure 7, which includes a discharge layer made of a negative metal, a value of the thermal expansion coefficient of this discharge layer, and a good material. The linear expansion coefficient of 111 and the intermediate 1fI of 41
The problem of spark plug tip falling off is improved by forming a cylindrical tip consisting of a stress relaxation layer having an expansion coefficient of 1, and bonding this stress relaxation layer to the FJ of the center electrode.

[Problems that the invention solves]

-1 When VJ-building a spark plug using the cylindrical composite piece 1, the surface 8 of the stress relaxation layer of the chip shown in Fig. 8 is joined to the base material 1 of the center electrode by resistance welding or the like. However, it was difficult to distinguish between the surface 8 of the stress relaxation layer and the surface 7 of the metal discharge layer. There was a risk that it would be joined to Material 1. =b bv1 Metal discharge part layer surface 7 is R
When bonded to T material 1, the reliability of the spark plug lugs is reduced by 111) due to cracks or oxide formation.

(Objective of the Invention) The present invention t, 1.11 "1 Reliably identifies the surface on the stress relaxation layer side where the full bending lightning 81S layer and the stress relaxation layer are separated into f=horn [11] An object of the present invention is to manufacture a spark plug for an internal combustion engine, in which the reliability of the bonding operation of the tip to the base material is ensured.

[Means for solving problems]

J-' In order to achieve the above object, the present invention provides a method for manufacturing a spark plug for an internal combustion engine, which includes a chip C having a white metal discharge layer and a stress relaxation layer bonded to the discharge layer.
In the step of providing the chip in which the end dimensions of the negative metal discharge layer and the end dimensions of the stress relaxation layer are different from each other, due to the difference in dimensions at both ends of the depth, the stress relaxation layer side of the depth is The method is characterized by a step of determining the end portion, and a step of joining the determined end portion on the side of the IC stress relaxation layer to the center electrode 1 (1 material).

In addition, the edge of the chip on the stress relaxation layer side can be colored to distinguish it from the negative metal discharge layer, and the surface of the edge on the stress relaxation layer side or the edge of the negative metal discharge layer can be colored. Distinguishing roughness as different things-b''
C-kill.

For reliable identification, the composite depth should preferably have a truncated conical shape, with the end diameter of the negative metal discharge layer being D7 and the end diameter on the stress relaxation layer side. It was confirmed that the stress relaxation layer side and the discharge layer can be reliably distinguished from each other if 1O-D81≧0.05 mm, that is, if the difference between DI and D8 is 0.05 mm or more.

The invention will now be described in detail with reference to Examples.

(One example of a large door) Example 1 The ignition part of the spark plug is shown in Figure 2. The shape of the tip is shaped like a circular trapezoid with a height of 0.05 to 1.5 mm, and the tip is platinum-shaped. jiFjlr'i 7I
The diameter (Dy) of the i-section end 7 is 0.4b to 3.0mm.
The diameter (1) 8) of the end portion 8 of the stress relaxation layer is 0.5-3.
(b) What happened to mm? In this case D8-1)7≧0,05
mm" C, the end of the stress relaxation layer can be reliably distinguished from the end of the discharge part e k. Next, the end 8 of the stress relaxation layer is resisted.
J was welded to the tip of the center electrode 7, and a C spark plug was made with NA.

Example 2 As shown in Figure 3, the shape of the chip is 0.0.
5--Mold into a truncated cone shape with a height of 1.5 mm.
mm, the diameter of the stress relaxation layer end 8 ([)8)'io,
/1 Ri-3, OOmm In the case of Example 1, the diameter of the end of the discharge part was made larger than the diameter of the end of the stress relaxation layer.This 15J combination 1)7-1')8≧ 0.0!'j m
With m-C, six people have been able to reliably identify the stress relaxation layer from 0.05 mm. Next, the stress relaxation layer end 8 of this composite chip 1 was joined to the end R1 of the center electrode 1 by anti-welding to produce a spark plug.

Example 3 As shown in Fig. 4, the shape of the boot tube that forms the ignition part of the spark plug is formed into a conical shape with a height of 0.05 to 1.5 tnm and a bottom diameter of 0.5 to 3 mm. The stress relaxation layer was reliably identified by setting the bottom side of the cone as the stress relaxation layer and the top side of the cone as the discharge layer. Next, the bottom of this stress relaxation layer (a certain cone) was joined to the end of the center electrode 1 by resistance welding to manufacture a spark plug.

Example 4: The ignition part of a spark plug is placed at a height of 0.
, 05-1, 5 mm and a diameter of 0.5 to 3.0 scale, formed into a circular IJ shape, plated copper on the edge surface ``11'' on the side of the city part layer, and colored the edge 1.: Next, after identifying the stress relaxation layer side of this chip by whether it is colored or not, this stress relaxation layer is joined to the end of the center electrode 1, and the spark plug is set to vJ speed 7.
．． -9 The thickness of the copper metal fitting 4- is preferably 60 μm or more. Also, use copper alloy, gold, or gold alloy instead of copper! , Color the stress relaxation M side edge/JI L'
U is also good, and steaming treatment can be used instead of plating treatment.

(Example) Set the ignition part of the spark plug to a height of 0.
, 05"-'l, 5 mm and diameter 0..5 ~
3.0am circle! , was formed into an L-shape, and the end on the stress relaxation layer side was lapped to give a mirror finish. Next, check whether there is a mirror-like end surface C on the stress relaxation layer side of this depth:
This stress relaxation layer is then bonded to the end of the center electrode 1 to produce a spark plug. Mirror finish by the above wrapping process [Leand blasting instead?
In method 4, the stress relaxation layer can be identified as a rough surface by roughening the edge of the stress relaxation layer, or one of these treatments can be applied to the edge of the discharge layer side. It is also possible to perform C identification. When surface roughness is expressed as the average height of the uneven portions on the surface, the average height of the uneven portions on the rough surface described in item 1 is approximately twice the average height of the uneven portions on the surface of one end that is not roughened. + , -8ka, 5195-cIyjr 4゜1-
On open sides 1 to 5, stress relaxation h'? J
The spark plug was manufactured by carefully separating the discharge layer and the grounding type 013 facing this chip.
Even when a deep layer is used, a spark plug can be manufactured by identifying the stress relaxation layer by the method shown in Examples 1 to 5 and joining the stress relaxation layer to the ground electrode by a joining means such as resistance welding.

In the present invention, for the purpose of improving performance after the chips are joined by resistance welding or the like, the vicinity of the discharge portion of the center electrode chip may be machined into a cylindrical shape to have a smaller diameter.

〔Effect of the invention〕

According to the method of the present invention, it is possible to reliably identify the stress relaxation layer of the ignition part (a certain chip) of a spark plug, and to prevent the discharge part layer of the deep part from being erroneously joined to the end of the center electrode.
This has made it possible to manufacture reliable spark plugs.

[Brief explanation of drawings]

Figures 1a and 11) are a partially cross-sectional front view of a spark plug made by the method of the present invention and an enlarged front view of the main part (a) of the spark plug, respectively; Figure 3 is a cross-sectional view of a truncated cone-shaped chip used in an embodiment of the method of the present invention; 4 is a cross-sectional view of a chip having a circular θ11 shape used in yet another embodiment of the method of the present invention, and FIGS. 5 and 6 show a chip having a single layer. Figure 7) shows the cracks and oxidized parts found in conventional spark plugs, and shows the main part of the B-respark lug. [Puta sparkp, ragni]: Hemostasis of the main part - 1r is established.
J is a small stop diagram of the main parts of a conventional spark plug. FIG. 10 is a side view showing the main parts of a spark plug with a protruding spark 4C/neck. In the figure, 1 is the center electrode, 2 is the chip made by Jii base, 3 is the ground electrode, 4 is the bonding interface between the chip and the center electrode, 5 is the discharge layer, 6 is the stress relaxation layer, 58 is the crack, and number 5b We accept oxides. Asamura Kaoru Figure 1 O Figure 2 Fang 3 Figure 4 Fang 5 Figure 6 Figure 8 Day Off Figure O 9

Claims (12)

[Claims] (1) A chip comprising a center electrode, a discharge layer made of n-gold/Iil, and a stress relaxation layer bonded to the discharge layer, and which is bonded to the center electrode via the stress relief layer, faces the depth. In a method of manufacturing a spark plug for an internal combustion engine, which has a ground electrode spaced apart from each other, the method for the end portion of the discharge layer of the horn, and the θ for the six lateral portions on the stress relaxation layer side. is′j
In addition to the step of setting different depths, and the step of determining the end of the depth on the stress relief layer side due to the difference in method between the two ends of the pusher, The above two methods are characterized in that the step includes the step of joining the depth to the center electrode through the end portion on the side of the stress relaxation layer. (2) The method for manufacturing an internal combustion 11 Sekikawa spark plug according to claim 1, wherein the shape of the depth is a truncated cone. (3) The method for manufacturing a spark plug for an internal combustion engine according to claim 2, where + (inside ε1 [diameter of one bottom of the trapezoid) - (diameter of the other bottom of the truncated cone) 1≧C1.05m . (4) The method for manufacturing a spark plug for an internal combustion engine according to claim 3, wherein the diameter of the truncated conical bottom on the stress relaxation layer side is larger than the diameter of the truncated conical bottom on the discharge layer side. (5) The method for manufacturing a spark plug for an internal combustion engine according to claim 3, wherein the diameter of the trapezoidal bottom of the circle 611 on the stress relaxation layer side is smaller than the diameter of the truncated conical bottom on the discharge layer side. (6) The method for manufacturing a spark plug for an internal combustion engine according to claim 1, wherein the pusher has a circular button shape and a stress relaxation layer is provided on the bottom side of the circular button. (7) A chip comprising a center electrode, a negative metal discharge layer and a stress relaxation layer joined to the discharge layer and joined to the center electrode via the stress relaxation layer, and a chip facing the chip; In the method for manufacturing a spark glove for an internal combustion engine, the end of the h'im layer of item 1 is separated from the end of the stress relaxation layer. The step of applying a color different from the surface color to the surface of the J and providing a bump on the surface, and determining the end of the chip on the stress relaxation layer side due to the difference in color at both ends of one bump. and bonding the chip to a center electrode via the end on the stress relaxation layer side, which is determined by nF. (8) Evaporate or deposit 1 on the edge of the discharge layer of the depth.
According to the claim, a different color is applied to the ends of the discharge layer, such as the ends of the stress relaxation layer, by applying one weight of thin lI9 selected from the group consisting of copper, gold, copper alloys and gold alloys. nIJ manufacturing method for internal combustion 11 Kannai spark plug according to item 7. (9) FA￥! 9. The method of manufacturing a spark plug for an internal combustion engine according to claim 8, wherein the thickness of the thin film reduced by (-1) is less than or equal to 5/l In. (10) The method for manufacturing a spark plug for an internal combustion engine according to claim 8, wherein the thickness of the thin film imparted by 4'J by METS-V is 60μ71'1 or less. (11) A chip comprising a center electrode, a discharge layer made of a negative metal, and a stress relaxation layer bonded to the discharge layer and bonded to the center electrode via the stress relief layer, and a chip facing the depth. In a method of manufacturing a spark plug for an internal combustion engine having a ground electrode spaced apart from each other, a surface treatment is applied to the surface of either one of the discharge layer end portion and the stress relaxation layer end portion of the depth. a step of forming a chip with an end portion having a surface roughness that is different from the other end; The method described above is characterized in that the step of joining the depth to the center electrode via the end on the relaxation layer side is performed on the right side. (12) The difference in surface roughness at both ends of the chip is a patent claim in which the difference in average height of the surface unevenness at the end of the chip is more than twice the average height of the surface unevenness at the other end. The range of! l
Method '0 according to Section 11