JP7307707B2 - Spark plug - Google Patents

Description

The present disclosure relates to spark plugs.

BACKGROUND ART As a spark plug for ignition used in an internal combustion engine, a spark plug is known which is attached to the engine head so that the tip is exposed in the combustion chamber, and generates spark discharge between the tip of the center electrode and the ground electrode. (For example, Patent Document 1).

JP 2019-46742 A

In general, an airflow of air-fuel mixture is generated in the combustion chamber, and the airflow may stretch the discharge path of the spark discharge. In the spark plug disclosed in Patent Document 1, the distance over which the discharge path is extended is long, and as a result, a large amount of energy may be required for ignition, and there is room for improvement in terms of ignition performance. Therefore, there is a demand for a technique capable of improving the ignition performance of spark plugs.

The present disclosure can be implemented as the following forms.

(1) According to one aspect of the present disclosure, a spark plug is provided. The spark plug includes an insulator having a through hole formed along the axial direction, a center electrode having a tip portion protruding from the tip of the through hole in the axial direction, and a metal shell accommodating the insulator. and a ground electrode connected to the metal shell, wherein the ground electrode includes a base end portion connected to the metal shell and extending along the axial direction, and the axial line of the base end portion. a bent portion that is continuous with the tip of the direction and is bent toward the center electrode; and, at the distal end portion in the extending direction of the extending portion, the proximal end portion extends from one end side to the other end side in the width direction of the extending portion when viewed from the axial direction. When viewed in the axial direction, the other end of the hatched portion, which is the end on the other end side, is the rear end of the extending portion in the extending direction. It is characterized by being positioned on the other end side of the center of the width. According to the spark plug of this aspect, when viewed from the axial direction, the distal end portion in the extending direction of the extending portion is separated from the base end portion from one end side in the width direction of the extending portion toward the other end side. Since the hatched portion is formed, the spark plug is positioned so that one end in the width direction of the extended portion of the ground electrode is positioned upstream in the direction of airflow, and the other end is positioned downstream in the direction of airflow. , the discharge path of the spark discharge can be guided to the tip side of the extending portion in the extending direction. Since no member that inhibits the flow of sparks is arranged on the tip side of the extending portion in the extending direction, the discharge path of the spark discharge is guided to the tip side of the extending portion in the extending direction. Inhibition of spark flow can be suppressed. In addition, since the other end of the hatched portion, which is the end on the other end side, is located on the other end side of the center of the width of the rear end of the extending portion in the extending direction, the other end is not affected by the air flow. can be positioned downstream in the direction of For this reason, it is possible to prevent the length of the discharge path in the spark discharge induced toward the distal end side in the extending direction from becoming excessively long, so that the energy required for ignition can be reduced. Therefore, the ignition performance of the spark plug can be improved.

(2) In the spark plug of the above aspect, the other end portion may be located at the other end of the extension portion in the width direction. According to this aspect of the spark plug, the other end portion is located at the other end in the width direction of the extended portion, so that the other end portion can be located further downstream in the airflow direction. . Therefore, it is possible to further suppress the length of the discharge path in the spark discharge from becoming excessively long, and as a result, it is possible to reduce the energy required for ignition.

(3) In the spark plug of the above aspect, the other end portion may be positioned further to the tip side than the tip portion in the extension direction of the extension portion when viewed from the axial direction. According to this aspect of the spark plug, the other end portion is positioned closer to the distal end than the distal end portion of the center electrode in the extending direction, so that the position of the spark discharge can be guided toward the distal end in the extending direction. As a result, it is possible to further suppress the obstruction of the flow of the spark, and to further suppress the deterioration of the ignition performance of the spark plug.

(4) In the spark plug of the above aspect, at least a portion of the tip portion is located between the other end portion and the hatched portion in the extending direction of the extending portion when viewed from the axial direction. It may be positioned between the one-end-side end, which is the end on the one-end side. According to the spark plug of this aspect, when viewed from the axial direction, at least a portion of the tip of the center electrode is positioned between the other end of the hatched portion and the one end of the portion in the extending direction. Therefore, when viewed from the axial direction, it is possible to suppress excessive separation between the position of the tip of the center electrode and the position of the hatched portion. Therefore, the position of spark discharge can be controlled to a relatively fixed position.

(5) In the spark plug of the above aspect, the tip portion and the hatched portion may overlap when viewed from the axial direction. According to this aspect of the spark plug, when viewed from the axial direction, the tip of the center electrode overlaps the hatched portion of the ground electrode. Excessive separation from the position of the hatched portion can be further suppressed. Therefore, the position of spark discharge can be controlled to a relatively fixed position.

The present invention can be embodied in various forms, such as a method for manufacturing a spark plug, an engine head to which a spark plug is attached, and the like.

FIG. 2 is a partial cross-sectional view showing a schematic configuration of a spark plug; FIG. 2 is a plan view of the tip of the spark plug viewed from the tip side in the axial direction; Explanatory drawing which shows an airflow and spark discharge. FIG. 7 is a plan view showing the configuration of the essential parts of the spark plug of the second embodiment; FIG. 11 is a plan view showing the configuration of the essential parts of the spark plug of the third embodiment; FIG. 4 is a plan view showing an example of the configuration of a ground electrode in another embodiment 1; FIG. 4 is a plan view showing an example of the configuration of a ground electrode in another embodiment 1;

A. Embodiment:
FIG. 1 is a partial cross-sectional view showing a schematic configuration of a spark plug 100 as one embodiment of the present disclosure. In FIG. 1, the external shape of the spark plug 100 is shown on the right side of the paper, and the cross-sectional shape of the spark plug 100 is shown on the left side of the paper, with the axis CA, which is the axial center of the spark plug 100, as the boundary. In the following description, the lower side in FIG. 1 (the side on which the ground electrode 40 described later is arranged) along the axis CA is called the tip side, and the upper side in FIG. side) is called the rear end side, and the direction along the axis CA is called the axial direction AD. In FIG. 1, for convenience of explanation, the engine head 90 to which the spark plug 100 is attached is indicated by a dashed line. The spark plug 100 is attached to the engine head 90 so that its tip is exposed inside the combustion chamber 95 .

A spark plug 100 includes an insulator 10 , a center electrode 20 , a metal shell 30 , a ground electrode 40 and a terminal metal fitting 50 . Axis CA of spark plug 100 coincides with the axes of insulator 10 , center electrode 20 , metal shell 30 , and terminal metal fitting 50 .

The insulator 10 has a substantially tubular external shape with a through hole 11 formed along the axial direction AD. The through hole 11 accommodates a portion of the center electrode 20 on the front end side and a portion of the terminal fitting 50 on the rear end side. Therefore, the insulator 10 holds the center electrode 20 within the through hole 11 . The insulator 10 has a front end portion accommodated in a shaft hole 38 of the metal shell 30 , which will be described later, and a rear end portion exposed from the shaft hole 38 . The insulator 10 is composed of an insulator formed by firing a ceramic material such as alumina.

The center electrode 20 is a rod-shaped electrode extending along the axial direction AD. A tip portion 21 of the center electrode 20 protrudes from the tip of the through hole 11 . A noble metal tip made of, for example, an iridium alloy may be joined to the distal end portion 21 .

A part of the center electrode 20 is inserted into the front end side of the through hole 11 of the insulator 10 , and a part of the terminal fitting 50 is inserted into the rear end side of the through hole 11 of the insulator 10 . . In the through hole 11 of the insulator 10, between the center electrode 20 and the terminal fitting 50, from the front end side to the rear end side, a front end side sealing material 61, a resistor 62, and a rear end side are arranged in order from the front end side to the rear end side. A side seal member 63 is arranged. Therefore, the center electrode 20 is electrically connected to the terminal fitting 50 at the rear end side through the front end side seal member 61 , the resistor 62 and the rear end side seal member 63 .

The resistor 62 is made of ceramic powder, a conductive material, glass, and an adhesive. The resistor 62 functions as an electrical resistance between the terminal fitting 50 and the center electrode 20, thereby suppressing the generation of noise when spark discharge is generated. The front end side sealing material 61 and the rear end side sealing material 63 are each made of conductive glass powder. In the present embodiment, the front end side sealing material 61 and the rear end side sealing material 63 are made of a mixed powder of copper powder and calcium borosilicate glass powder.

The metal shell 30 has a substantially tubular external shape with a shaft hole 38 formed along the axial direction AD, and holds the insulator 10 in the shaft hole 38 . The metal shell 30 is made of, for example, low-carbon steel, and is entirely plated with nickel plating, zinc plating, or the like.

A tool engaging portion 31 and a male screw portion 32 are formed on the outer periphery of the metallic shell 30 . The tool engaging portion 31 engages with a tool (not shown) when attaching the spark plug 100 to the engine head 90 . The male threaded portion 32 has a screw thread formed on the outer peripheral surface at the distal end portion of the metal shell 30 and is screwed into the female threaded portion 93 of the engine head 90 .

The ground electrode 40 is composed of a bar-shaped metal member having a substantially rectangular cross section and is connected to the tip 37 of the metallic shell 30 . Like the center electrode 20, the ground electrode 40 of this embodiment is made of a nickel alloy containing nickel as a main component. The ground electrode 40 has a base end portion 41, a bent portion 42, and an extended portion 43 that are connected in this order from the rear end side in the axial direction AD.

The base end portion 41 has one end connected to the front end 37 of the metal shell 30 and extends along the axial direction AD. One end of the bent portion 42 connects to the other end of the base end portion 41 and bends toward the center electrode 20 . In other words, bent portion 42 is bent toward axis CA of spark plug 100 . The extending portion 43 extends in the radial direction of the spark plug 100 so that an extending direction rear end 49 , which will be described later, continues to the other end of the bent portion 42 , that is, the end opposite to the base end portion 41 . In the following description, the direction in which the extending portion 43 extends is also referred to as "extending direction ED". A detailed description of the configuration of the extension portion 43 will be given later. A discharge gap G1 for spark discharge is formed between the tip portion 21 of the center electrode 20 and the extended portion 43 facing in the axial direction AD. An electrode tip made of, for example, an iridium alloy may be provided at a portion of the extended portion 43 that faces the tip portion 21 of the center electrode 20 .

The terminal fitting 50 is provided at the rear end portion of the spark plug 100 . The tip side of the terminal fitting 50 is accommodated in the through hole 11 of the insulator 10 , and the rear end side of the terminal fitting 50 is exposed from the through hole 11 . A high voltage cable (not shown) is connected to the terminal fitting 50 to apply a high voltage. This application causes spark discharge in the discharge gap G1. A spark generated in the discharge gap G1 ignites the air-fuel mixture in the combustion chamber 95 .

FIG. 2 is a plan view of the tip of the spark plug 100 viewed from the tip side in the axial direction AD. In FIG. 2, for convenience of explanation, the position of the base end portion 41 is indicated by a dashed line, and the position of the extending direction rear end 49 is indicated by a two-dot chain line. In the following description, the leading end portion of the extending portion 43 in the extending direction ED is also referred to as "extending direction leading end portion 44". A hatched portion 45 is formed at the extension direction tip portion 44 .

The hatched portion 45 is a surface formed along the axial direction AD. formed apart. In the present embodiment, the hatched portion 45 is formed as a plane that monotonously separates from the base end portion 41 as it goes from one end side to the other end side in the width direction WD of the extension portion 43 . 2, the one end side of the extension portion 43 in the width direction WD is described as the left side of the extension portion 43 in the paper surface, and the other end side of the extension portion 43 in the width direction WD is described as the right side of the extension portion 43 in the paper surface. described.

In the following description, the end of the hatched portion 45 on the other end side in the width direction WD is called the other end side end portion 47 , and the end on the one end side in the width direction WD is called the one end side end portion 48 . The other end portion 47 is positioned at the tip of the hatched portion 45 in the extending direction ED, and the one end portion 48 is positioned at the rear end of the hatched portion 45 in the extending direction ED. The other end portion 47 is located on the other end side in the width direction WD from the center of the width of the extension direction rear end 49 located at the rear end of the extension portion 43 in the extension direction ED. That is, the other end portion 47 is located on the other end side in the width direction WD from the center of the width of the portion of the extension portion 43 excluding the extension direction tip portion 44 . In other words, the other end portion 47 is positioned closer to the other end than the center axis AX of the ground electrode 40 in the width direction WD.

In the present embodiment, the other end portion 47 is located at the other end of the extension portion 43 in the width direction WD, and the one end portion 48 is located at one end of the extension portion 43 in the width direction WD. ing. For this reason, the shaded portion 45 is formed in a tapered shape connecting one end and the other end of the extension portion 43 in the width direction WD.

In the present embodiment, the other end portion 47 is located on the distal side of the distal end portion 21 of the center electrode 20 in the extending direction ED. Further, the tip portion 21 of the center electrode 20 is positioned between the other end portion 47 and the one end portion 48 in the extending direction ED when viewed from the axial direction AD.

FIG. 3 is an explanatory diagram showing airflow and spark discharge. In FIG. 3, on the same plane as in FIG. 2, an example of the flow direction of the air-fuel mixture in the combustion chamber 95 (hereinafter also referred to as "air flow direction F") is indicated by a thick arrow, and the spark generated in the discharge gap G1 An example of the position of the discharge path S is indicated by a thick dashed line. The spark plug 100 is arranged such that one end side of the extending portion 43 of the ground electrode 40 in the width direction WD is positioned upstream in the airflow direction F, and the other end side is positioned downstream in the airflow direction F. attached to the

If a spark discharge is generated in a state where no airflow is generated, the spark is generated at the position where the tip 21 of the center electrode 20 and the extended portion 43 of the ground electrode 40 are connected at the shortest distance in the discharge gap G1. A discharge path S is formed. However, in reality, since the above-described air current is generated around the discharge gap G1, the discharge path S may be stretched by the air current.

As described above, the shaded portion 45 formed in the spark plug 100 of the present embodiment has a base end that increases from one end side to the other end side in the width direction WD of the extension portion 43 when viewed from the axial direction AD. Away from part 41. Therefore, when the airflow direction F is from one end side to the other end side of the extended portion 43, the starting point of the discharge path S on the side of the center electrode 20 is located in the hatched portion 45 in the axial direction AD. It is guided toward the other end 47 through the leading edge. As a result, the discharge path S is extended downstream in the direction indicated by the white arrow in FIG. Here, on the downstream side in the direction X when viewed from the tip portion 21 of the center electrode 20, no member that inhibits the flow of sparks is arranged. Therefore, it is possible to prevent the flow of sparks from being obstructed by the discharge path S being stretched in the direction X, so the above configuration is desirable from the viewpoint of flame spread.

In general, if the length of the discharge path S is excessively long, a large amount of energy may be required for ignition, and the spark S may not be generated. However, in the spark plug 100 of the present embodiment, the other end portion 47 of the hatched portion 45 is located on the other end side in the width direction WD from the center of the width of the rear end of the extending portion 43 in the extending direction. Therefore, the other end 47 can be positioned downstream in the direction F of the airflow. Therefore, the length of the discharge path S can be prevented from becoming excessively long, and as a result, the energy required for ignition can be reduced. Therefore, efficient ignition can be achieved with small energy.

According to the spark plug 100 of the present embodiment described above, the extending direction distal end portion 44 of the extending portion 43 is provided with a gap from the base end portion 41 toward the other end side in the width direction WD of the extending portion 43 . Since the oblique line portion 45 is formed, the discharge path S can be guided to the tip side of the extending portion 43 in the extending direction ED. Here, since no member that inhibits the flow of sparks is arranged on the tip side of the extension part 43 in the extension direction ED, the discharge path S is arranged to the tip side of the extension part 43 in the extension direction ED. By inducing it, it is possible to suppress the inhibition of spark flow. In addition, since the other end portion 47 of the hatched portion 45 is located on the other end side of the center of the width of the rear end of the extending portion 43 in the extending direction, the other end portion 47 is positioned in the direction F of the airflow. can be positioned downstream in the Therefore, it is possible to prevent the discharge path S of the spark guided to the distal end side in the extension direction ED from becoming excessively long, so that the energy required for ignition can be reduced. Therefore, the ignition performance of the spark plug 100 can be improved.

In addition, since the other end 47 of the hatched portion 45 is located at the other end of the extension portion 43 in the width direction WD, the other end 47 is located further downstream in the airflow direction F. be able to. Therefore, it is possible to prevent the length of the spark discharge path S from becoming excessively long, and as a result, the energy required for ignition can be reduced.

Further, since the other end portion 47 is located on the distal end side of the distal end portion 21 of the center electrode 20 in the extending direction ED, the position of the spark discharge can be guided toward the distal end side in the extending direction ED. As a result, it is possible to further suppress the flow of the spark from being obstructed, and to further suppress the deterioration of the ignition performance of the spark plug 100 . In addition, since the other end portion 47 is located on the distal end side of the distal end portion 21 of the center electrode 20 in the extending direction ED, the other end portion 47 is located at the distal end of the center electrode 20 in the extending direction ED. Compared to the configuration located on the rear end side of the portion 21, it is possible to suppress the spark of the discharge path S extended by the airflow from being cut off, thereby suppressing the deterioration of the ignition performance of the spark plug 100.

Further, the tip portion 21 of the center electrode 20 is positioned between the other end portion 47 and the one end portion 48 in the extending direction ED when viewed from the axial direction AD. Therefore, when viewed from the axial direction AD, it is possible to suppress excessive separation between the tip portion 21 of the center electrode 20 and the hatched portion 45, thereby controlling the position of spark discharge to a relatively fixed position. can do.

Further, since the hatched portion 45 is formed as a flat surface that monotonously separates from the base end portion 41 toward the other end in the width direction WD of the extension portion 43, the configuration of the hatched portion 45 is not complicated. As a result, complication of the manufacturing process of the ground electrode 40 can be suppressed.

B. Second embodiment:
FIG. 4 is a plan view showing the configuration of the essential parts of the spark plug of the second embodiment. In FIG. 4, as in FIG. 2, only the ground electrode 40a is extracted and shown in a plane in which the tip of the spark plug is viewed from the tip end side in the axial direction AD. The ground electrode 40a provided in the spark plug of the second embodiment differs from the ground electrode 40 provided in the spark plug 100 of the first embodiment in that it has an extension direction tip portion 44a instead of the extension direction tip portion 44. FIG. Since other configurations are the same as those of the spark plug 100 of the first embodiment, the same configurations are denoted by the same reference numerals, and detailed description thereof will be omitted.

A hatched portion 45a and a connection portion 46a are formed in the extension direction tip portion 44a. Both the hatched portion 45a and the connection portion 46a are surfaces formed along the axial direction AD. In the present embodiment, the other end portion 47a of the hatched portion 45a is located between the center of the extension portion 43a in the width direction WD and the other end thereof. The connection portion 46a connects the other end portion 47a and the other end of the extension portion 43a in the width direction WD. In the present embodiment, the connection portion 46a is formed as a plane along the width direction WD of the extension portion 43a. From the viewpoint of locating the starting point of spark discharge further downstream in the direction of the airflow, the dimension of the connecting portion 46a along the width direction WD of the extending portion 43a is one-third or less of the width of the extending portion 43a. is preferable, and it is more preferable that it is 1/4 or less.

According to the spark plug including the ground electrode 40a of the second embodiment described above, effects similar to those of the first embodiment are obtained. In addition, a connection portion 46a that connects the other end portion 47a and the other end in the width direction WD of the extension portion 43a is formed at the extension direction tip portion 44a. For this reason, the spark plug is attached to the engine head so that one end in the width direction WD of the extended portion 43a of the ground electrode 40a is positioned upstream in the airflow direction, and the other end is positioned downstream in the airflow direction. In this case, the starting point of spark discharge can be guided from the hatched portion 45a to the connection portion 46a. Here, since the dimension of the connection portion 46a along the width direction WD of the extension portion 43a is relatively small, by guiding the starting point of the spark discharge to the connection portion 46a, the position of the spark discharge is relatively fixed. can be controlled to

C. Third embodiment:
FIG. 5 is a plan view showing the configuration of the essential parts of the spark plug of the third embodiment. In FIG. 5, as in FIG. 2, only the ground electrode 40 and the tip portion 21b of the center electrode 20b are extracted and shown in a plane when the tip of the spark plug is viewed from the tip side in the axial direction AD. The spark plug of the third embodiment differs from the spark plug 100 of the first embodiment in the positional relationship between the tip portion 21b of the center electrode 20b and the hatched portion 45. FIG. Since other configurations are the same as those of the spark plug 100 of the first embodiment, the same configurations are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the spark plug of the third embodiment, the tip portion 21b of the center electrode 20b and the shaded portion 45 overlap when viewed from the axial direction AD. In other words, the hatched portion 45 crosses the tip portion 21b of the center electrode 20b when viewed in the axial direction AD. Therefore, the tip portion 21b of the center electrode 20b is positioned between the other end portion 47 and the one end portion 48 of the hatched portion 45 in the extending direction ED when viewed from the axial direction AD. Moreover, it is positioned between the other end 47 and the one end 48 of the hatched portion 45 in the width direction WD of the extension portion 43 .

According to the spark plug of the third embodiment described above, the same effects as those of the first embodiment are obtained. In addition, when viewed from the axial direction AD, the tip portion 21b of the center electrode 20b overlaps the hatched portion 45, so when viewed from the axial direction AD, the tip portion 21b of the center electrode 20b and the hatched portion 45 are aligned. Excessive separation from the position of the portion 45 can be further suppressed. Therefore, the position of spark discharge can be controlled to a relatively fixed position.

D. Other embodiments:
D-1. Alternative Embodiment 1:
The configuration of the ground electrodes 40, 40a in each of the above-described embodiments is merely an example, and various modifications are possible. For example, in each of the above-described embodiments, the hatched portions 45 and 45a are formed as planes that monotonously separate from the base end portion 41 toward the other end side in the width direction WD of the extension portion 43. It may be a curved surface or the like.

6 and 7 are plan views showing an example of the configuration of the ground electrode 40c according to another embodiment 1. FIG. In FIGS. 6 and 7, as in FIG. 2, only the ground electrode 40c is extracted and shown in the plane of the tip of the spark plug viewed from the tip end side in the axial direction AD. In the above-described second embodiment, the connection portion 46a is formed as a plane along the width direction WD of the extension portion 43a, but the present disclosure is not limited to this. For example, as shown in FIG. 6, the connection portion 46c formed at the extension direction distal end portion 44c is separated from the base end portion 41 toward the one end side from the other end side in the width direction WD of the extension portion 43c. good too. Further, for example, as shown in FIG. 7, the connection portion 46c may be formed as a curved surface that connects the other end portion 47a and the other end of the extension portion 43a in the width direction WD. Such a configuration also provides the same effects as those of the above-described embodiments.

D-2. Alternative Embodiment 2:
The positional relationship between the tip portions 21, 21b of the center electrodes 20, 20b and the hatched portions 45, 45a in each of the above-described embodiments is merely an example, and various changes are possible. For example, in the above-described first embodiment, the other end portion 47 is positioned closer to the distal end than the distal end portion 21 of the center electrode 20 in the extending direction ED. However, the position of the other end portion 47 in the extending direction ED may overlap the tip portion 21 of the center electrode 20 or may be on the rear end side of the tip portion 21 of the center electrode 20 . Further, for example, in the first embodiment, the tip portion 21 of the center electrode 20 is located between the other end portion 47 and the one end portion 48 in the extension direction ED when viewed from the axial direction AD. was located. However, part of the distal end portion 21 of the center electrode 20 may be positioned between the other end portion 47 and the one end portion 48 in the extending direction ED when viewed from the axial direction AD. . That is, in general, at least part of the tip portion 21 of the center electrode 20 is positioned between the other end portion 47 and the one end portion 48 in the extending direction ED when viewed from the axial direction AD. may Further, for example, at least a portion of the tip portion 21 of the center electrode 20 may be located on the tip side of the other end portion 47 in the extension direction ED when viewed from the axial direction AD. It may be located on the rear end side of the side end portion 48 . Even with such a configuration, the same effects as those of the above-described embodiments can be obtained.

The present invention is not limited to the above-described embodiments, and can be implemented in various configurations without departing from the spirit of the present invention. For example, the technical features in the embodiments corresponding to the technical features in the respective modes described in the Summary of the Invention section can be used to solve some or all of the above problems, or Substitutions and combinations may be made as appropriate to achieve part or all. Also, if the technical features are not described as essential in this specification, they can be deleted as appropriate.

DESCRIPTION OF SYMBOLS 10... Insulator 11... Through hole 20, 20b... Center electrode 21, 21b... Tip part 30... Metal shell 31... Tool engaging part 32... Male screw part 37... Tip 38... Shaft hole , 40, 40a, 40c... ground electrode, 41... base end part, 42... bending part, 43, 43a, 43c... extension part, 44, 44a, 44c... extension direction tip part, 45, 45a... hatched part, 46a, 46c... Connecting part 47, 47a... Other end part 48... One end part 49... Extension direction rear end 50... Terminal fitting 61... Tip side sealing material 62... Resistor 63 Rear end seal 90 Engine head 93 Female screw 95 Combustion chamber 100 Spark plug AD Axial direction AX Center axis CA Axial ED Extending direction F Direction of airflow, G1... discharge gap, S... discharge path, WD... width direction, X... direction

Claims (3)

an insulator having a through hole formed along an axial direction; a center electrode having a tip protruding from a tip of the through hole in the axial direction; a metal shell housing the insulator; A spark plug comprising a ground electrode connected to
The ground electrode is
a base end portion connected to the metal shell and extending along the axial direction;
a bending portion connected to the tip of the base end portion in the axial direction and bending toward the center electrode;
an extending portion that is connected to an end of the bent portion on the side opposite to the base end portion and forms a discharge gap with the tip portion;
has
A tip part in the extending direction of the extending part is formed with a slanted part which is separated from the base end part from one end side in the width direction of the extending part toward the other end side when viewed from the axial direction. and
When viewed from the axial direction, the other end of the hatched portion, which is the end on the other end side, is closer to the other end than the center of the width of the rear end of the extending portion in the extending direction. located ,
The other end portion is located at the other end of the extension portion in the width direction,
The spark plug, wherein the other end portion is located on the tip side of the tip portion in the extension direction of the extension portion when viewed from the axial direction. The spark plug according to claim 1 ,
At least a part of the tip portion is, when viewed from the axial direction, the other end portion and the one end portion of the hatched portion that is the end of the one end side in the extension direction of the extension portion. A spark plug, characterized in that it is located between the ends. The spark plug according to claim 2 ,
A spark plug, wherein the tip portion and the hatched portion overlap when viewed from the axial direction.

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