JPS6220151Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a spark plug equipped with a gasket ring that is fitted onto a mounting bracket.

[Prior Art] Conventionally, as shown in Fig. 1, an annular flat part 4, which is formed by bending a cylindrical metal thin plate and comes into contact with the shoulder surface of a mounting bracket of a spark plug, and a circular part 4 extending from the flat part toward the center. an inner circumferential edge 5 extending outward from the planar portion and bent outward at a predetermined curvature and having an inner diameter somewhat larger than the thread diameter of the mounting screw 22; An outer circumferential edge 6 that is bent back toward the center at a predetermined curvature on the same side as the inner circumferential edge (lower side in the figure) and has an outer diameter that approximates the outer diameter of the body of the mounting bracket, and a bent back of the outer circumferential edge. A spark plug mounting seat of an engine, which is extended from the end of the inner circumferential edge, is brought into contact with or close to the outer surface of the bent portion of the inner circumferential edge, and is bent outward with a small curvature on the same side as the outer circumferential edge. There is an ignition plug in which a gasket ring 30 having a contact portion 8 is fitted onto a screw neck 23 between the body of the mounting fitting 2 and the mounting screw.

[Problems to be solved by the invention] However, when this spark plug is removed from the engine for the purpose of inspection, replacement, etc., the gasket ring comes off from the spark plug due to seizure by oil and is left behind in the cylinder head. It may take some time to remove it. In addition, in recent years, spark plugs have been automatically assembled, so the gasket ring must be located at the threaded neck of the spark plug, not at the threaded part of the mounting bracket.However, with conventional gasket rings, the threaded part Because of this, there were cases where smooth automatic assembly was not possible. This deviation of the gasket ring from the threaded neck can be solved by making the outer diameter of the threaded neck smaller than the root diameter of the mounting screw and the inner diameter of the inner peripheral edge of the gasket ring. This results in a disadvantage that the mechanical strength of the screw neck of the mounting bracket is reduced.

The purpose of this invention is to enable the gasket ring to be reliably and firmly connected to the threaded neck of the spark plug without reducing the mechanical strength of the threaded neck of the mounting bracket, thereby facilitating automatic assembly of the spark plug. To provide an ignition plug with a gasket ring which can prevent the gasket ring from coming off when the ignition plug is removed.

[Means for Solving the Problems] In order to achieve the above object, the spark plug of the present invention has the following features: a. A large-diameter body, a mounting screw to the cylinder head, and a mounting screw provided between the body and the mounting screw. a cylindrical mounting bracket having a screw neck with an outer diameter approximately equal to the root diameter of the screw, and a shoulder surface between the body and the screw neck; b) formed by bending a cylindrical metal thin plate; , an annular flat part that comes into contact with the shoulder surface of the mounting bracket;
It is formed by extending from the planar part toward the center and bending back outward at a predetermined curvature,
It is formed by extending outward from the planar part and being bent back toward the center at a predetermined curvature on the same side as the inner peripheral edge, and has an inner diameter smaller than the crest diameter of the mounting screw, and a root diameter of the mounting screw. It is larger and has a part whose dimension (thickness) in the central axis direction is larger than the axial length (valley width) between the crests of the mounting screws located on the same radius from the central axis of the mounting bracket. an inner circumferential edge, an outer circumferential edge having an outer diameter approximate to the outer diameter of the body of the mounting bracket, and an outer circumferential edge extending from the bent end of the outer circumferential edge to abut or be close to the outer surface of the bent portion of the inner circumferential edge; a gasket ring having an abutting portion for the engine spark plug mounting seat formed by folding outward with a small curvature on the same side as the outer peripheral edge, and externally fitted onto the screw neck of the mounting bracket; A configuration with the following features was adopted.

[Example] Next, the present invention will be explained based on the example shown in FIGS. 2 to 7.

1 is the spark plug, 2 is the mounting bracket, 21 is the body, 2
Reference numeral 2 denotes a mounting screw that is screwed into the spark plug mounting screw hole provided in the cylinder head of the engine, and 23 is a mounting screw 2 that is provided between the body 21 and the mounting screw 22.
A screw neck having an outer diameter approximately equal to the root diameter of No. 2, 24
is a shoulder surface on the side of the screw neck 23 of the body 21, and this shoulder surface has an inclination of about 3 degrees to allow a tool to escape when machining the shoulder surface 24 and the screw neck 23. 3 is a gasket ring of a spark plug according to the present invention,
It is formed by bending a thin cylindrical metal plate with a thickness of 0.2 mm and an outer diameter of 14 mm. This gasket ring has an annular flat part 4 that comes into contact with the shoulder surface 24 of the mounting bracket when attached to the spark plug, and a thickness H of about 1.15 mm that extends from the flat part 4 toward the center. an inner circumferential edge 5 which is bent outward with a curvature such that An outer circumferential edge 6 that is bent back toward the center with a predetermined curvature on the same side as the inner circumferential edge and has an outer diameter that is approximately the same as the outer diameter of the body 21 of the mounting bracket, and a bent portion 7 of the outer circumferential edge 6. is extended from the end of the inner circumferential edge to be close to the outer surface of the bent portion 7 of the inner circumferential edge, and is bent outward from an intermediate position between the outer circumferential edge 6 and the inner circumferential edge 5 with a small curvature on the same side as the outer circumferential edge. The cylinder head has an abutting portion 8 for the spark plug mounting seat formed by the cylinder head.

The inner circumferential edge 5 of the gasket ring is formed as shown in FIGS.
As shown in the figure, it has a substantially cylindrical shape with a length of about 0.8 mm to 1.2 mm, which is curved from the planar portion 4 toward the center with a minimum radius of curvature of 0.7 to 1.0 mm, and about 250 degrees to 280 degrees. The maximum radius of curvature from this cylindrical inner peripheral edge 5 is 0.5 to 0.7 mm.
The bent part 12 was bent back by approximately 110 degrees to 150 degrees.
is provided, and the outer surface of the bent portion 12 is in contact with the inner surface of the contact portion 8 to the ignition plug mounting seat. At this time, the inner diameter of the cylindrical inner peripheral edge 5 is set to be somewhat larger than the thread diameter of the mounting screw. The gasket ring of the spark plug having this cross section is fitted onto the screw neck 23 of the mounting fitting 2 from the mounting screw side. Next, the bent portion 12 is compressed in the axial direction from one side (lower side in the figure) to be plastically deformed, and the inner peripheral edge 5 is bulged toward the center. At this time, the inner circumferential edge 5 of the gasket ring has an inner diameter smaller than the top diameter of the mounting screw 22 and larger than the root diameter, and the gasket ring 3 is extremely narrow at the screw neck 23 of the mounting bracket as shown in FIG. It is loosely fitted while maintaining a gap. Furthermore, as shown in Figure 7,
The dimension (thickness) of the inner peripheral edge 5 of this gasket ring in the central axis direction is the axial length (thread length) between the ridges of the mounting screws 22 located on the same radius from the central axis of the mounting bracket. The width of the valley is set to be larger than the width of the valley.

With this setting, the gasket ring 3 having the shape shown in FIGS. 5 and 6 is fitted into the mounting bracket 2 of the ignition plug, and the inner peripheral edge 5 is bulged toward the center. It becomes impossible to fit around the outer circumference of the screw 22, and the gasket ring 3
is securely held in the screw neck 23 of the mounting bracket.

At the same time as the inner peripheral edge 5 of the gasket ring is compressed, punching 90 is performed to form three claws 9 protruding toward the center as shown in FIGS. 2 to 4, and the tips of the three claws 9 are As shown in FIG. 2, it may be made to lightly abut against the screw neck 23 of the mounting fitting. In this case, when the gasket ring 3 is fitted onto the screw neck 23 of the mounting bracket, the gasket ring 3
The tips of the two claws 9 are in contact with the outer surface of the screw neck 23, and since the gasket ring 3 has the same axis as the mounting bracket, the entire circumference of the gasket ring 3 is adjusted to the taper of the shoulder surface 24 of the mounting bracket. are located on the same radius from the center. As a result, when the ignition plug is installed on the engine, the gasket ring 3 is compressed uniformly between the shoulder surface 24 of the mounting bracket, the cylinder head, and the ignition plug mounting seat (not shown).
It deforms evenly and reliably prevents seal failure.

[Effect of the invention] The spark plug of the invention has an inner diameter of the gasket ring that is smaller than the crest diameter of the mounting screw, larger than the root diameter of the mounting screw, and has a dimension (thickness) in the central axis direction. Since it is set to have a part larger than the axial length (tread width of the thread) between the crests of the mounting screws located on the same radius from the center of the mounting bracket, the screw neck of the mounting bracket is Even if the outer diameter is set to be almost the same as the root diameter of the mounting screw, the gasket ring can be securely held on the screw neck of the mounting bracket, allowing automatic assembly of the ignition plug to be performed smoothly, and the ignition plug to be easily assembled. This prevents the gasket ring from coming off when removing the gasket ring.

[Brief explanation of the drawing]

Figure 1 is a front view of the main parts of a conventional spark plug with a gasket ring, Figure 2 is a front view of the main parts of the spark plug of the present invention, and Figure 3 is a front sectional view of the gasket ring of the spark plug of the present invention. , Fig. 4 is a plan view thereof, Fig. 5 is a front sectional view of the gasket ring of the ignition plug of the present invention before the ignition plug is installed, Fig. 6 is an enlarged cross-sectional view thereof, and Fig. 7 is the ignition plug of the present invention. FIG. 3 is a front sectional view of the gasket ring of FIG. In the figure, 3... gasket ring, 4... annular flat part, 5... inner circumferential edge, 6... outer circumferential edge, 8... contact part to the spark plug mounting seat, 9... pawl, 21... Body of mounting bracket, 22...Mounting screw, 23...Screw head.

Claims (1)

[Scope of Claim for Utility Model Registration] a. A large diameter body 21, a mounting screw 22 to the cylinder head, and a screw provided between the body and the mounting screw and having an outer diameter approximately equal to the root diameter of the mounting screw. neck 23
a cylindrical mounting bracket 2 having a shoulder surface 24 between the body and the screw neck; b a circle formed by bending a thin cylindrical metal plate and abutting against the shoulder surface of the mounting bracket; An annular planar portion 4 is formed by extending toward the center from the planar portion and being bent outward at a predetermined curvature, and has an inner diameter smaller than the thread diameter of the mounting screw;
and an inner peripheral edge 5 having a portion that is larger than the root diameter of the mounting screw and whose dimension in the central axis direction is larger than the axial length between the crests of the mounting screws located on the same radius from the central axis of the mounting bracket. , an outer peripheral edge that extends outward from the planar part and is bent back toward the center at a predetermined curvature on the same side as the inner peripheral edge, and has an outer diameter that approximates the outer diameter of the body of the mounting bracket; 6, and is formed by being extended from the end of the bent portion of the outer peripheral edge, brought into contact with or close to the outer surface of the bent portion of the inner peripheral edge, and folded outward at a small curvature on the same side as the outer peripheral edge. 1. An ignition plug comprising: a contact portion 8 for contacting an ignition plug mounting seat of an engine; and a gasket ring 3 externally fitted onto a screw neck of the mounting fitting.