JPH0223979Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a mounting structure for a spark plug in various gas combustion appliances in which a piezoelectric ignition device is incorporated.

[Prior Art] A mounting structure for a spark plug in a piezoelectric ignition type gas combustion appliance, such as a gas stove or a gas instantaneous water heater, generally has a structure as shown in an exploded view in FIG. In the figure, 10 is a rod-shaped discharge electrode, 10a is a discharge part formed at one end, and 11
is an insulator for the discharge electrode 10, and encloses the rod-shaped discharge electrode 10 with both ends exposed. Reference numeral 11a denotes a constricted portion provided in the middle in the longitudinal direction of the insulator 11, into which a mounting fitting of the insulator 11 is fitted, and its cross section is circular. Reference numeral 12 denotes a metal fitting for mounting the insulator 11, which is made by folding a highly elastic band-shaped metal plate into an arrowhead shape, and has an outwardly bulging shape on both legs that serves to grip the constricted portion 11a. Part 12a
are provided for each. Reference numeral 13 denotes a mounting base for the spark plug, on which, in addition to the spark plug, a secondary burner 15 for igniting the main burner of the gas appliance, a counter electrode 16, a gas flow guide plate 17, a cover member 18 near the spark plug, etc. are mounted. It will be done. Reference numeral 14 denotes a mounting bracket 12 bored into the spark plug mounting base 13.
By forcefully pushing the arrowhead-shaped portion of the mounting bracket 12 into the locking hole using the elasticity of the metal material, the mounting bracket 12 itself can be attached to the mounting base. 13 and between a pair of bulging shaped portions 12a provided on the legs,
The constriction portion 11a of the insulator 11 of the spark plug is tightly squeezed and gripped. In addition
Reference numeral 14' denotes a fitting hole for the mounting fitting 12 provided in the cover member 18 for protecting the vicinity of the mounting portion of the ignition plug from falling water droplets, etc., and is overlapped so as to match the fitting and locking hole 14.

[Problems to be Solved by the Invention] In the conventional spark plug mounting structure as described above, the insulator 11 of the rod-shaped discharge electrode 10 has a constricted portion with a circular cross section into which the mounting fitting 12 is fitted. 11a, but as it is well known, insulators are porcelain products made by molding ceramic materials using a casting method etc. and firing them at high temperatures, so such deep uneven shapes are not possible. It is inherently difficult to produce products with high efficiency while keeping the incidence of defective products low, and the production costs have inevitably increased.

In addition, with conventional mounting brackets that are simply bent metal strips into the shape of an arrowhead, it is difficult to expect sufficient dimensional accuracy in the finished molding. It was not always easy to lock it.

SUMMARY OF THE INVENTION An object of the present invention is to provide a spark plug mounting structure that is easier to manufacture and can be firmly installed in a precise mounting position.

[Means for Solving the Problems] In order to achieve the above object, the spark plug mounting structure of the present invention is made of an elastic metal plate, has a rectangular tube shape with a U-shaped cross section, and A rod-shaped discharge electrode is insulated and covered with a mounting bracket in which the free end of the cylindrical wall is bent inward in a nearly Z-shape to form a pair of mounting legs, and a prismatic insulator having a groove on a part of its outer circumferential surface. The ignition plug is made up of a combination of a spark plug and a spark plug assembly base provided with holes for fitting the pair of mounting legs, and the base of the mounting legs is fitted into the groove, A configuration is adopted in which the insulator is elastically held by the mounting bracket.

[Operations and Effects of the Invention] The spark plug mounting structure constructed as described above consists of an elastic metal plate placed in a concave groove provided on the outer circumferential surface of a prismatic insulator, with a U-shaped cross section. A strong mounting structure can be obtained by fitting the cylindrical mounting bracket onto the outside so that the base of the mounting leg is inserted, and then fitting the mounting leg into the mounting hole provided in the spark plug mounting base. .

With such a mounting structure, there is no need to form a deep constriction in the insulator as in the past, and it is sufficient to provide a shallow groove, so the insulator can be manufactured more easily and efficiently. Moreover, since the insulator is elastically held on its peripheral wall surface by the cylindrical fitting, dimensional errors in the molding of the insulator can be absorbed, and the insulator can be firmly attached.

[Embodiment] The spark plug mounting structure of the present invention will be specifically described below based on an embodiment shown in the accompanying drawings.

Fig. 1 is a perspective view of the vicinity of the ignition plug mounting part of a gas stove, illustrating the ignition plug mounting structure according to the present invention, and Fig. 2 is an exploded perspective view of the assembled structure of Fig. 1, where 1 is made of magnetic material. The ignition plug A is formed of a prismatic insulator, and is formed by encasing a rod-shaped discharge electrode 2 with its discharge portion 2a and terminal portion 2b exposed. A shallow groove 1a is formed on the surface that contacts the mounting base.

Reference numeral 3 denotes a mounting bracket for the spark plug A, which is made by processing an elastic metal plate and has a rectangular tube shape with a substantially U-shaped cross section, and the opposing free ends of the tube walls are extended. By giving each of them an inwardly bent Z-shape, the bent end 4 functions as a mounting leg of the mounting fitting 3. Reference numeral 5 denotes an assembly base for the spark plug, which is made of a metal plate, and in addition to being provided with a hole 6 for fitting the mounting leg 4 of the mounting bracket 3 of the spark plug A, a base 5 is provided at a position facing the discharge part 2a of the discharge electrode. A counter electrode 16 is integrally formed therein. 15 is an auxiliary burner for igniting the main burner (not shown); 17 is an auxiliary burner 1;
5 is a guide plate for the gas ejected from the ignition plug, and 18 is a cover member to prevent boiled liquid from falling from above the spark plug during cooking, and is a cover member for the fitting hole 6' of the mounting bracket 3. These are all attached to an assembly base 5.

FIG. 3 is a side sectional view of the vicinity of spark plug A, showing the state where spark plug A has been installed on its assembly base 5, FIGS. 4 and 5 are front and side views of spark plug A, Figures 6 and 7 show mounting bracket 3, respectively.
The pair of mounting legs 4 of the mounting bracket 3 are used to fix the mounting bracket 3 in pressure contact with the assembly base 5;
A check claw 4a is integrally provided to prevent the device from falling off. The backstop 4a is formed by punching the mounting leg 4 into a U-shape and extruding a tongue-like portion outward. Further, on the opposing cylinder wall surfaces of the mounting bracket 3 having a rectangular cylindrical cross section, the punched grooves 3a each having a U-shaped, U-shaped, or H-shaped planar shape are formed so as to hang over one remaining cylinder wall surface. Therefore, the tongue-like portions 3b are also formed on the wall surfaces of both cylinders. The two opposing cylinder wall surfaces of the rectangular cylindrical mounting bracket 3 are not simply flat surfaces, but are given a bulging shape 3d that is approximately arcuate toward the inside of the cylinder, and The tongue-shaped portion 3b exerts an elastic pressing force on both side surfaces and the top surface of the prismatic insulator 1, and the mounting bracket 3 causes the insulator 1 to
The gripping and locking force is sufficiently increased. As mentioned at the beginning, it is difficult to expect good dimensional accuracy from the insulator 1 made of magnetic material, so there may be some variation between the inner circumferential dimension of the mounting bracket 3 and the outer circumferential dimension of the insulator. Even if this occurs, this dimensional error is effectively absorbed by the presence of the two elastically deformable tongue portions 3b and the cylinder wall surface 3c. Furthermore, the horizontal portion 4b forming the base of the mounting leg 4 of the mounting bracket 3 is configured to fit into the shallow groove 1a provided on the outer circumferential surface of the prismatic insulator 1. Tsute insulator 1
When the insulator 1 is squeezed and gripped, the mounting bracket protrudes from the mounting surface of the insulator 1 by its wall thickness, preventing the insulator, the mounting surface, and the mounting base 5 from coming into close contact with each other, resulting in a significant decrease in mounting stability. The inconvenience of lowering can be avoided, and the inconvenience of the insulator 1 shifting within the cylindrical fitting 3 due to some external force after installation also does not occur. Therefore, according to the mounting structure of the present invention, the spark plug A can be mounted sufficiently firmly on the assembly base 5 while maintaining a predetermined correct mounting position. By bending the lower end portion 4c of the mounting leg 4 of the mounting bracket 3 inward, when the insulator 1 is fitted into the mounting bracket 3, a pair of This eliminates the inconvenience that the mounting legs 4 each spread outward, making it difficult to insert them into the fitting holes 6 of the mounting base 5.

The manufacturing method of the prismatic insulator 1 requires a mold with a complicated shape, whereas the conventional insulator that is provided with a constricted part for fitting the mounting bracket as described above requires a mold with a complicated shape. This mold is used to efficiently form the ceramic material into a prismatic shape and then fire it.Next, a large number of prismatically fired insulator materials are arranged in parallel, and the insulator rows are ground by a grinder. By performing the processing simultaneously, the grooves 1a can be formed all at once. At the time of molding the prismatic insulator 1, the rod-shaped discharge electrode 2 is simultaneously embedded. Such a prismatic molded body can be made by extrusion molding a ceramic material, and it is also possible to form it sufficiently efficiently by providing a mold with a protrusion for forming the groove 1a. can.

[Brief explanation of drawings]

Fig. 1 is a perspective view of the vicinity of the ignition plug mounting part of a gas stove, illustrating the ignition plug mounting structure according to the present invention, Fig. 2 is an exploded view of the assembly structure of Fig. 1, and Fig. 3 shows the ignition plug in its assembly. Figures 4 and 5 are front and side views of the spark plug, and Figures 6 and 7 are front views of the mounting bracket, respectively. A side end view, and FIG. 8 is an exploded perspective view of the vicinity of a spark plug mounting portion of a gas stove, illustrating a conventional spark plug mounting structure. In the figure, A...Spark plug, 1...Prismatic insulator, 1a...Concave groove, 2...Discharge electrode, 3...Mounting bracket, 3a...Punching groove, 4...Mounting leg, 4a... …
Claw piece, 5...Assembly base.

Claims (1)

[Claims for Utility Model Registration] 1. A rectangular cylinder made of an elastic metal plate with a U-shaped cross section, the opposing free ends of the cylinder walls being bent inward into an almost Z-shape to provide a pair of attachments. A mounting bracket having legs formed therein, a spark plug formed by insulating a rod-shaped discharge electrode with a prismatic insulator having a groove on a part of its outer circumferential surface, and holes for fitting the pair of mounting legs are provided. The spark plug is assembled with an assembly base, and the insulator is elastically held by the mounting bracket by fitting the base of the mounting leg into the groove. Mounting structure for spark plugs. 2. Approximately U-shaped,
The spark plug mounting structure according to claim 1, wherein a punched groove having a U-shaped or H-shaped planar shape is provided so as to extend over the remaining wall surface of the cylinder. 3. The mounting of the spark plug according to claim 1 or 2 of the utility model registration claim, wherein the cylinder wall surface of the rectangular cylindrical mounting bracket is given an inwardly bulging shape. structure. 4. Claims 1 to 4 of the Utility Model Registration Claims, characterized in that each of the pair of mounting legs is provided with a backstop for preventing the leg from falling out of the fitting hole. A mounting structure for a spark plug according to any of Item 3.