JPS614182A - Spark plug - 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] The present invention relates to joining a spark plug insulator and a fitting.

[Prior Art] In conventional spark plugs, the insulator and the mounting bracket are fitted by fitting the insulator to the step of the mounting bracket through a gasket at the leading end step of the body, and attaching the insulator to the step seat of the mounting fitting through a packing. A powder filling method in which powder such as talcum is compressed and filled into the part, and a metal ring is placed and caulked.One method is to fill the rear end of the body of the insulator with powder, but to fill it with a thin wall part provided in a part of the mounting bracket. A large current is applied to make it red hot,
Two electric heat crimping methods are in use that perform simultaneous crimping. In these two methods, the part to be filled with powder, the part to be caulked, and the part to which the seal is fitted are determined relative to the insulator, so the length of the insulator and the mounting bracket is determined according to the length of the spark plug. This has also changed, and production management has become more complicated as each spark plug with different specifications requires a different mounting bracket. In addition, the gaskets that dissipate the heat received by the tip of the center electrode from the combustion chamber of the engine through the insulator were only interposed between the insulator taper step and the taper step of the mounting bracket, which resulted in poor heat dissipation and heat resistance. The sex was inferior. In addition, since the material interposed between the mounting bracket and the insulator is talc or packing, the adhesion is poor, and pressure of several tons of actual load must be applied to the packing surface, resulting in problems with gas leakage and poor heat resistance. Ta.

[Objective of the Invention] The object of the present invention is to simplify the productivity of spark plugs with different shapes, and to improve heat resistance and gas leakage prevention, since the mounting brackets are common and centering and crimping are easy. Our goal is to provide spark plugs that can meet your needs.

[Structure of the Invention] The spark plug of the present invention is a spark plug in which a rod-shaped center electrode is covered with a cylindrical insulator, and a metal cylindrical mounting bracket is fitted on the outside of the cylindrical insulator. To fit the insulator with the mounting bracket, two or more grooves in the circumferential direction are provided in the body that serves as the fitting surface of the insulator, and a metal ring including at least one pipe-shaped ring is fitted into the groove. A metal sleeve-like packing is fitted onto the tapered stepped portion including the tip of the body provided on the body, and is press-fitted into the inner cavity of the mounting bracket, and the rear end of the mounting bracket is caulked inward. It is constructed by deforming and fitting a metal ring.

[Effects of the Invention] The spark plug having the above configuration has the following effects. .

b) Two or more circumferential grooves are provided in the body of the insulator to interpose a ring, and the insulator is press-fitted into the inner cavity of the mounting bracket via a sleeve-like packing, making it easy to install the mounting bracket. The position of the spark plug is movable, which improves the means for producing spark plugs with different axial dimensions of the mounting bracket and the insulator.

(Example) As the number of rings increases, the gap between the insulator and the mounting bracket decreases, and the degree of sealing increases, so gas leakage reduction can be set as appropriate depending on the purpose, and the prevention of insulator removal is improved. .

c) Centering the plug becomes easier by fitting two or more of the rings having the same inner and outer diameters onto the insulator and press-fitting them into the mounting bracket.

2) Since the sleeve-shaped packing is pressed into engagement with the insulator trunk, the tapered stepped portion, and the tapered stepped seat of the mounting bracket, heat conduction is improved, heat radiation is increased, and heat resistance is improved. In addition, since the area of the adhesive portion of the packing increases, the degree of adhesion increases, and gas leakage and leakage are prevented.

e) The insulator is made of alumina, the front door mounting bracket is made of iron-based metal, and the ring and gasket interposed therebetween are made of copper, aluminum, or an alloy mainly composed of these.
By doing so, the crimping pressure can be reduced to about 115 compared to the conventional method.

[Example] Fig. 1 shows a spark plug according to a first example of the present invention, in which 1 is a mounting bracket, 2 is an insulator, 3 is a rod-shaped center electrode,
4 is an outer electrode, 5 is a pipe-shaped ring, 6 is a linear ring,
7 is a sleeve-like packing.

The mounting bracket 1 is formed with a mounting screw 9 for fitting the spark plug of the present invention into the combustion chamber when the engine is installed.
A tip mounting screw part IA having a stepped seat 11 in the inner cavity 10, an intermediate body part IB having a large diameter through a gasket seat surface 12 of the mounting screw 9, and a rear end part 1 having a hexagonal bolt shape.
A rod-shaped outer electrode 4 is welded to the tip of the mounting screw portion 1A, and the tip of the outer electrode 4 is bent to face the tip surface of the center electrode to form an air discharge gap. are doing.

The insulator 2 is made of electrically insulating ceramic such as alumina, and has a tapered end leg portion 2A having a small outer diameter and a tapered portion exposed to the combustion chamber side. An intermediate body portion 2B having an intermediate outer diameter is formed, and the body portion 2
It has a cylindrical shape with two or more circumferential grooves 22 from B and a rear end 2C with a corrugation 23 on the terminal electrode side, and a shaft hole is provided in the center and a rod-shaped center electrode 4 is provided in the shaft hole. 3 protrudes from the tip and is sealed. Center electrode 3 is made of Ni-8i-Cr
-Al, made of a nickel-based alloy such as Ni-Cr-Fe, or with a core material such as copper sealed inside the insulator 2, and placed in the tip hole of the shaft hole of the insulator 2, with a resistor in the middle part. Terminal electrode 1 is connected via conductive glass layer 15 with body 14 in between.
It is sealed together with 6.

As shown in FIG. 1, this insulator 2 has a linear ring 6 made of metal such as iron or stainless steel on the tip side of the circumferential groove 22 of the rear end portion 2C, and a ring 6 made of metal such as iron or stainless steel on the rear end side of the circumferential groove 22. A pipe-shaped ring 5 made of the same material as the ring 6 is fitted, and a sleeve-shaped packing 7 is fitted from the distal leg portion 2A, and this is inserted into the bore 10 of the mounting bracket 1 on the rear end surface of the insulator or the end of the terminal electrode. The step part of the sleeve-shaped packing 7 is locked to the inner cavity step seat 11 by pressing the part, preferably by ultrasonic press-fitting,
At the same time, the circumferential side ta of the sleeve-like packing 7 and the rings 5 and 6 are pressed into the inner cavity. Next, the rear end 1 of the mounting bracket 1
3 is caulked inward using a caulking jig (not shown), preferably cold caulked, and the pipe-shaped ring 5 is crushed and deformed, so that the insulator and the fitting are fitted together. The sleeve-shaped packing 7 is made of a soft metal such as copper, aluminum, or an alloy containing these metals as main components, and these packings 7 are bonded in advance to an insulator by metallization, or the prepared packing is heat-treated (approximately 1030°C). They may be joined together.

Further, as shown in FIG.
The sleeve-shaped packing 1 is press-fitted into the inner cavity step 11 of the mounting fitting 1 so as to form a gap 8 in the axial direction without being locked.

In the case of this embodiment, the mounting bracket 1 can be used as a common component, and only the distal end leg portion 2A of the insulator 2 can be applied to a case where the length in the axial direction is increased. Furthermore, as shown in FIG. 3, the present invention is such that the inner cavity step 11 of the mounting fitting 1 in the above embodiment is eliminated, and a sleeve-shaped packing 7 is press-fitted therein. By eliminating the lumen step of the mounting fitting 1, the manufacturing of the fitting is simplified and costs are reduced.

[Brief explanation of drawings]

FIGS. 1, 2, and 3 are side views, partially in cross section, of the spark plug of the present invention, each showing an embodiment.

Claims (1)

[Claims] 1) A spark plug in which a rod-shaped center electrode is covered with a cylindrical insulator, and a metal cylindrical mounting bracket is fitted on the outside of the spark plug, wherein the insulator and the mounting bracket are connected to each other. For fitting, two or more grooves in the circumferential direction are provided in the body that becomes the fitting surface of the insulator, and a metal ring including at least one pipe-shaped ring is fitted into the groove. A metal sleeve-shaped packing is fitted onto the tapered stepped portion including the tip of the body and press-fitted into the inner cavity of the mounting bracket, and the rear end of the mounting bracket is caulked inward to secure the metal ring. A spark plug characterized by being deformed and fitted. 2) The pipe-shaped ring is fitted into the circumferential groove at the rearmost end, and is crushed when the rear end of the mounting bracket is caulked inward to tightly seal the fitting surface between the mounting bracket and the insulator. A spark plug according to claim 1, characterized in that: 3) The sleeve-shaped packing is made of thin-walled soft metal;
The inner cavity of the mounting bracket is provided with a tapered step seat corresponding to the tapered step provided on the insulator, and the insulator is provided with a caulked portion inside the rear end of the mounting bracket and a tapered step of the mounting bracket. Claim 1, wherein the sleeve-shaped packing is interposed between the tapered seat of the mounting fitting and the tapered stepped portion of the insulator in a compressed state. The spark plug described in item 2.