JP6869202B2

JP6869202B2 - Spark plug

Info

Publication number: JP6869202B2
Application number: JP2018061534A
Authority: JP
Inventors: 裕則上垣; 翔麻津曲
Original assignee: NGK Spark Plug Co Ltd
Current assignee: NGK Spark Plug Co Ltd
Priority date: 2018-03-28
Filing date: 2018-03-28
Publication date: 2021-05-12
Anticipated expiration: 2038-03-28
Also published as: JP2019175647A

Description

本発明はスパークプラグに関し、特に磁性体を内蔵したスパークプラグに関するものである。 The present invention relates to a spark plug, and more particularly to a spark plug containing a magnetic material.

放電時に発生する電波ノイズを抑えるために、主体金具の内側に絶縁保持された導電体の周囲に磁性体を配置したスパークプラグが知られている（特許文献１）。特許文献２に開示された技術では、磁性体は種類が異なる複数の磁性材料を含有する。 A spark plug in which a magnetic material is arranged around a conductor insulated and held inside a main metal fitting is known in order to suppress radio wave noise generated during discharge (Patent Document 1). In the technique disclosed in Patent Document 2, the magnetic material contains a plurality of different types of magnetic materials.

特開昭６２−１５０６８１号公報Japanese Unexamined Patent Publication No. 62-150681 特開２０１６−９５６７号公報Japanese Unexamined Patent Publication No. 2016-9567

しかしながら上記従来の技術では、電波ノイズの抑制のための十分な工夫がなされていない。 However, in the above-mentioned conventional technique, sufficient measures for suppressing radio wave noise have not been made.

本発明は上述した問題点を解決するためになされたものであり、より効果的にノイズを抑制できるスパークプラグを提供することを目的としている。 The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a spark plug capable of suppressing noise more effectively.

この目的を達成するために本発明のスパークプラグは、円筒状の主体金具と、主体金具の内側に絶縁保持され先端側から後端側へと軸線方向に延びる導電体と、導電体の周囲に配置される磁性体と、を備えている。磁性体は、透磁率の周波数特性が異なる磁性材料でそれぞれ形成される複数の磁性部材を備え、複数の磁性部材は、複数の磁性部材の全体の体積に対する、複数の磁性部材のうち磁性材料の透磁率の最大ピークを示す周波数が最も高い部材の体積の割合が最も大きい。 In order to achieve this object, the spark plug of the present invention has a cylindrical main metal fitting, a conductor that is insulated and held inside the main metal fitting and extends in the axial direction from the front end side to the rear end side, and around the conductor. It is equipped with a magnetic material to be arranged. The magnetic material includes a plurality of magnetic members each formed of magnetic materials having different magnetic permeability frequency characteristics, and the plurality of magnetic members are made of a magnetic material among the plurality of magnetic members with respect to the total volume of the plurality of magnetic members. The ratio of the volume of the member having the highest frequency showing the maximum peak of magnetic permeability is the largest.

請求項１記載のスパークプラグによれば、複数の磁性部材は、複数の磁性部材の全体の体積に対する、複数の磁性部材のうち磁性材料の透磁率の最大ピークを示す周波数が最も高い部材の体積の割合が最も大きい。ここで、透磁率の最大ピークを示す周波数が高い磁性材料ほど（つまり、ノイズの高周波成分に対して抑制機能を備える磁性材料ほど）、その最大ピークが低くなることが知られている。よって、ノイズの高周波成分の抑制効果が比較的低い部材の体積を最も大きくすることで、ノイズ抑制が低周波成分に偏らないように制御しながら、複数の磁性部材を用いることで広くなったノイズ抑制可能な周波数帯域の全域で、十分なノイズ抑制効果を得ることができる。 According to the spark plug according to claim 1, the plurality of magnetic members are the volumes of the member having the highest frequency indicating the maximum peak of the magnetic permeability of the magnetic material among the plurality of magnetic members with respect to the total volume of the plurality of magnetic members. The ratio of is the largest. Here, it is known that a magnetic material having a higher frequency showing the maximum peak of magnetic permeability (that is, a magnetic material having a function of suppressing a high frequency component of noise) has a lower maximum peak. Therefore, by maximizing the volume of the member having a relatively low effect of suppressing the high frequency component of noise, the noise becomes wider by using a plurality of magnetic members while controlling the noise suppression so as not to be biased to the low frequency component. A sufficient noise suppression effect can be obtained in the entire range of the suppressable frequency band.

請求項２記載のスパークプラグによれば、複数の磁性部材のうち、磁性材料の透磁率の最大ピークを示す周波数が最も高い部材の少なくとも一部は、主体金具の後端よりも後端側に配置される。ここで、主体金具の後端よりも先端側では、導電体を流れる電流の高周波成分の一部は主体金具を流れる。しかし、主体金具の後端よりも後端側では、電流の高周波成分のほぼ全てが導電体を流れる。従って、磁性材料の透磁率の最大ピークを示す周波数が最も高い部材の少なくとも一部を、主体金具の後端よりも後端側に配置することにより、導電体を流れる電流の高周波成分を抑制し易くできる。よって、請求項１の効果に加え、ノイズの高周波成分を抑制し易くできる。 According to the spark plug according to claim 2, at least a part of the members having the highest frequency showing the maximum peak of the magnetic permeability of the magnetic material among the plurality of magnetic members is located on the rear end side of the main metal fitting. Be placed. Here, on the tip side of the rear end of the main metal fitting, a part of the high frequency component of the current flowing through the conductor flows through the main metal fitting. However, on the rear end side of the main metal fitting, almost all of the high frequency components of the current flow through the conductor. Therefore, by arranging at least a part of the member having the highest frequency showing the maximum peak of the magnetic permeability of the magnetic material on the rear end side of the main metal fitting, the high frequency component of the current flowing through the conductor is suppressed. It can be made easy. Therefore, in addition to the effect of claim 1, it is possible to easily suppress the high frequency component of noise.

請求項３記載のスパークプラグによれば、複数の磁性部材のうち主体金具の後端よりも先端側に配置される先端部分は、複数の磁性部材のうち磁性材料の透磁率の最大ピークを示す周波数が最も高い部材の体積の割合が最も小さい。ここで、主体金具の後端よりも先端側では、導電体を流れる電流の高周波成分の一部は主体金具を流れる。また、電流の低周波成分は、主体金具の存在に関わらずほぼ全てが導電体を流れる。従って、先端部分において、透磁率の最大ピークを示す周波数が最も高い部材の体積の割合を最も小さくすることにより、請求項１又は２の効果に加え、ノイズの高周波成分を抑制しつつ、低周波成分を抑制し易くできる。 According to the spark plug according to claim 3, the tip portion of the plurality of magnetic members arranged closer to the tip side than the rear end of the main metal fitting indicates the maximum peak of the magnetic permeability of the magnetic material among the plurality of magnetic members. The volume ratio of the member with the highest frequency is the smallest. Here, on the tip side of the rear end of the main metal fitting, a part of the high frequency component of the current flowing through the conductor flows through the main metal fitting. In addition, almost all of the low-frequency components of the current flow through the conductor regardless of the presence of the main metal fittings. Therefore, in addition to the effect of claim 1 or 2, by minimizing the volume ratio of the member having the highest frequency showing the maximum peak of magnetic permeability at the tip portion, the low frequency is suppressed while suppressing the high frequency component of noise. It is possible to easily suppress the components.

請求項４記載のスパークプラグによれば、複数の磁性部材のうち主体金具の後端よりも後端側に配置される後端部分は、複数の磁性部材のうち磁性材料の透磁率の最大ピークを示す周波数が最も高い部材の体積の割合が最も大きい。ここで、主体金具の後端よりも先端側では、導電体を流れる電流の高周波成分の一部は主体金具を流れる。しかし、主体金具の後端よりも後端側では、電流の高周波成分のほぼ全てが導電体を流れる。従って、透磁率の最大ピークを示す周波数が最も高い部材を後端部分に多く配置することにより、請求項１から３のいずれかの効果に加え、ノイズの高周波成分を抑制し易くできる。 According to the spark plug according to claim 4, the rear end portion of the plurality of magnetic members arranged on the rear end side of the main metal fitting is the maximum peak of the magnetic permeability of the magnetic material among the plurality of magnetic members. The ratio of the volume of the member having the highest frequency indicating is the largest. Here, on the tip side of the rear end of the main metal fitting, a part of the high frequency component of the current flowing through the conductor flows through the main metal fitting. However, on the rear end side of the main metal fitting, almost all of the high frequency components of the current flow through the conductor. Therefore, by arranging a large number of members having the highest frequency showing the maximum peak of magnetic permeability at the rear end portion, in addition to the effect of any one of claims 1 to 3, it is possible to easily suppress the high frequency component of noise.

請求項５記載のスパークプラグによれば、複数の磁性部材は、第１部材と、自身の少なくとも一部が第１部材の少なくとも一部よりも径方向の外側に配置される第２部材と、を含む。第１部材を構成する磁性材料の透磁率の最大ピークを示す周波数は、第２部材を構成する磁性材料の透磁率の最大ピークを示す周波数よりも高い。ここで、透磁率の最大ピークを示す周波数が高い磁性材料ほど（つまり、ノイズの高周波成分に対して抑制機能を備える磁性材料ほど）、その最大ピークが低くなることが知られている。よって、第２部材よりも透磁率の最大ピークを示す周波数が高い第１部材を、第２部材よりも導電体の近くに配置することで、請求項１から４のいずれかの効果に加え、ノイズ抑制が低周波成分に偏らないように制御しながら、複数の磁性部材を用いることで広くなったノイズ抑制可能な周波数帯域の全域で、十分なノイズ抑制効果を得ることができる。 According to the spark plug according to claim 5, the plurality of magnetic members include a first member and a second member in which at least a part of itself is arranged radially outside of at least a part of the first member. including. The frequency indicating the maximum peak of the magnetic permeability of the magnetic material constituting the first member is higher than the frequency indicating the maximum peak of the magnetic permeability of the magnetic material constituting the second member. Here, it is known that a magnetic material having a higher frequency showing the maximum peak of magnetic permeability (that is, a magnetic material having a function of suppressing a high frequency component of noise) has a lower maximum peak. Therefore, by arranging the first member having a higher frequency showing the maximum peak of magnetic permeability than the second member closer to the conductor than the second member, in addition to the effect of any one of claims 1 to 4, the effect can be added. By using a plurality of magnetic members while controlling the noise suppression so as not to be biased to the low frequency component, it is possible to obtain a sufficient noise suppression effect over the entire frequency band in which the noise can be suppressed.

請求項６記載のスパークプラグによれば、軸線方向に延びる軸孔を有する絶縁体は、主体金具に外周側から保持される。導電体の周囲であって軸孔の内部に配置される磁性体の一部は、主体金具の後端よりも先端側に配置される。これにより、磁性体が全て主体金具の後端よりも後端側に配置される場合に比べて、磁性部材の体積を増やすことができるので、磁性部材による電波ノイズの抑制効果をより高めることができる。 According to the spark plug according to claim 6, the insulator having a shaft hole extending in the axial direction is held by the main metal fitting from the outer peripheral side. A part of the magnetic material around the conductor and arranged inside the shaft hole is arranged closer to the tip side than the rear end of the main metal fitting. As a result, the volume of the magnetic member can be increased as compared with the case where all the magnetic materials are arranged on the rear end side of the main metal fitting, so that the effect of suppressing radio wave noise by the magnetic member can be further enhanced. it can.

また、複数の磁性部材のうち体積抵抗率が最も低い部材は、その部材の全体が、主体金具の後端よりも後端側に配置される。その結果、主体金具と導電体との間に体積抵抗率が最も低い部材が配置されないようにできるので、請求項１から５のいずれかの効果に加え、主体金具と導電体との間の絶縁性を確保できる。 Further, the member having the lowest volume resistivity among the plurality of magnetic members is arranged on the rear end side of the main metal fitting as a whole. As a result, since the member having the lowest volume resistivity can be prevented from being arranged between the main metal fitting and the conductor, in addition to the effect of any one of claims 1 to 5, the insulation between the main metal fitting and the conductor can be prevented. Sex can be secured.

請求項７記載のスパークプラグによれば、軸線方向に互いに接する接触面を有する複数の磁性部材は、互いに合わさる凹凸が接触面に形成されているので、磁性部材をずれ難くできる。その結果、請求項６の効果に加え、振動等による磁性部材の破損を抑制できる。 According to the spark plug according to claim 7, since the plurality of magnetic members having contact surfaces in contact with each other in the axial direction are formed with irregularities that meet each other on the contact surfaces, the magnetic members can be prevented from slipping. As a result, in addition to the effect of claim 6, damage to the magnetic member due to vibration or the like can be suppressed.

請求項８記載のスパークプラグによれば、複数の磁性部材は、固定部材を介して互いに固定されているので、請求項１から７のいずれかの効果に加え、振動等による磁性部材の破損を抑制できる。 According to the spark plug according to claim 8, since the plurality of magnetic members are fixed to each other via the fixing member, in addition to the effect of any one of claims 1 to 7, the magnetic member may be damaged due to vibration or the like. Can be suppressed.

請求項９記載のスパークプラグによれば、磁性材料はＭｎ−Ｚｎフェライト及びＮｉ−Ｚｎフェライトを含有する。Ｍｎ−Ｚｎフェライトはノイズの低周波成分を抑制し易く、Ｎｉ−Ｚｎフェライトはノイズの高周波成分を抑制し易い。従って、請求項１から８のいずれかの効果に加え、これらの組合せにより各周波数帯域におけるノイズ抑制効果を制御しながら、広い周波数帯域でノイズ抑制効果を得ることができる。 According to the spark plug according to claim 9, the magnetic material contains Mn-Zn ferrite and Ni-Zn ferrite. Mn—Zn ferrite easily suppresses the low frequency component of noise, and Ni—Zn ferrite easily suppresses the high frequency component of noise. Therefore, in addition to the effect of any one of claims 1 to 8, it is possible to obtain the noise suppression effect in a wide frequency band while controlling the noise suppression effect in each frequency band by combining these.

第１実施の形態におけるスパークプラグの片側断面図である。It is one side sectional view of the spark plug in 1st Embodiment. 磁性材料の周波数特性の模式図である。It is a schematic diagram of the frequency characteristic of a magnetic material. 第２実施の形態におけるスパークプラグの片側断面図である。It is one side sectional view of the spark plug in 2nd Embodiment. 第３実施の形態におけるスパークプラグの片側断面図である。It is one side sectional view of the spark plug in 3rd Embodiment. （ａ）は第４実施の形態におけるスパークプラグの片側断面図であり、（ｂ）は第５実施の形態におけるスパークプラグの断面図である。(A) is a one-sided sectional view of the spark plug in the fourth embodiment, and (b) is a sectional view of the spark plug in the fifth embodiment.

以下、本発明の好ましい実施形態について添付図面を参照して説明する。図１は第１実施の形態におけるスパークプラグ１０の軸線Ｏを境にした片側断面図である。図１では、紙面下側をスパークプラグ１０の先端側、紙面上側をスパークプラグ１０の後端側という（図３から図５においても同じ）。スパークプラグ１０は、主体金具２０と、主体金具２０に絶縁保持された導電体３０と、導電体３０の周囲に配置された磁性体４０と、を備えている。 Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a one-sided cross-sectional view of the spark plug 10 in the first embodiment with the axis O as a boundary. In FIG. 1, the lower side of the paper surface is referred to as the front end side of the spark plug 10, and the upper side of the paper surface is referred to as the rear end side of the spark plug 10 (the same applies to FIGS. 3 to 5). The spark plug 10 includes a main metal fitting 20, a conductor 30 insulated and held by the main metal fitting 20, and a magnetic body 40 arranged around the conductor 30.

絶縁体１１は、主体金具２０と導電体３０とを電気的に絶縁するための部材であり、機械的特性や高温下の絶縁性に優れるアルミナ等により形成されている。絶縁体１１は、軸線Ｏに沿って軸孔が貫通することにより、第１内周面１２、第２内周面１３及び第３内周面１４が、後端側から先端側へ順に形成されている。第１内周面１２、第２内周面１３及び第３内周面１４の順に内径が小さくなる。 The insulator 11 is a member for electrically insulating the main metal fitting 20 and the conductor 30, and is formed of alumina or the like having excellent mechanical properties and insulating properties at high temperatures. In the insulator 11, the first inner peripheral surface 12, the second inner peripheral surface 13, and the third inner peripheral surface 14 are formed in order from the rear end side to the tip side by penetrating the shaft hole along the axis O. ing. The inner diameter decreases in the order of the first inner peripheral surface 12, the second inner peripheral surface 13, and the third inner peripheral surface 14.

絶縁体１１は、軸線方向の中央に外径が最も大きい大径部１５が形成されている。大径部１５の内側に、第１内周面１２と第２内周面１３との境界が位置する。絶縁体１１の外周面には、大径部１５よりも先端側であって、第３内周面１４の径方向の外側に全周に亘って先端向き面１６が形成されている。 The insulator 11 has a large diameter portion 15 having the largest outer diameter formed at the center in the axial direction. The boundary between the first inner peripheral surface 12 and the second inner peripheral surface 13 is located inside the large diameter portion 15. On the outer peripheral surface of the insulator 11, a tip-facing surface 16 is formed on the outer peripheral surface of the third inner peripheral surface 14 on the distal end side of the large-diameter portion 15 over the entire circumference.

主体金具２０は、絶縁体１１の外周に配置される円筒状の部材である。主体金具２０は、導電性を有する金属材料（例えば低炭素鋼等）によって形成されている。主体金具２０は、絶縁体１１の先端向き面１６を取り囲む胴部２１と、胴部２１の後端側に連接される座部２４と、座部２４の後端側に連接される屈曲部２５と、屈曲部２５に先端側が連接される工具係合部２６と、工具係合部２６の後端側に連接される後端部２７と、を備えている。胴部２１は、エンジン（図示せず）のねじ穴に螺合するおねじ２２が外周に形成されており、絶縁体１１の先端向き面１６を先端側から係止する棚部２３が内周に形成されている。座部２４は、エンジンのねじ穴とおねじ２２との隙間を塞ぐための部位であり、胴部２１の外径よりも外径が大きく形成されている。 The main metal fitting 20 is a cylindrical member arranged on the outer periphery of the insulator 11. The main metal fitting 20 is formed of a conductive metal material (for example, low carbon steel or the like). The main metal fitting 20 includes a body portion 21 surrounding the front end facing surface 16 of the insulator 11, a seat portion 24 connected to the rear end side of the body portion 21, and a bent portion 25 connected to the rear end side of the seat portion 24. A tool engaging portion 26 whose tip end side is connected to the bent portion 25, and a rear end portion 27 which is connected to the rear end side of the tool engaging portion 26 are provided. The body 21 has a male screw 22 screwed into a screw hole of an engine (not shown) formed on the outer circumference, and a shelf 23 for locking the tip facing surface 16 of the insulator 11 from the tip side is the inner circumference. Is formed in. The seat portion 24 is a portion for closing the gap between the screw hole of the engine and the male screw 22, and the outer diameter is formed to be larger than the outer diameter of the body portion 21.

屈曲部２５は、主体金具２０を絶縁体１１に組み付けるときに、塑性変形（屈曲）させて加締め固定するための部位である。工具係合部２６は、エンジンのねじ穴におねじ２２を締め付けるときに、レンチ等の工具を係合させる部位である。工具係合部２６及び屈曲部２５は、絶縁体１１の大径部１５を取り囲む。後端部２７は径方向の内側へ向けて屈曲し、大径部１５よりも後端側に位置する。後端部２７が屈曲した位置によって主体金具２０の後端２８の位置が決まる。主体金具２０は、棚部２３及び後端部２７によって、絶縁体１１の先端向き面１６及び大径部１５を保持する。接地電極２９は主体金具２０に接続される金属製（例えばニッケル基合金製）の部材である。 The bent portion 25 is a portion for plastically deforming (bending) and crimping and fixing when the main metal fitting 20 is assembled to the insulator 11. The tool engaging portion 26 is a portion for engaging a tool such as a wrench when tightening the screw 22 into the screw hole of the engine. The tool engaging portion 26 and the bent portion 25 surround the large diameter portion 15 of the insulator 11. The rear end portion 27 bends inward in the radial direction and is located on the rear end side of the large diameter portion 15. The position of the rear end 28 of the main metal fitting 20 is determined by the position where the rear end portion 27 is bent. The main metal fitting 20 holds the front end facing surface 16 and the large diameter portion 15 of the insulator 11 by the shelf portion 23 and the rear end portion 27. The ground electrode 29 is a metal member (for example, made of a nickel-based alloy) connected to the main metal fitting 20.

導電体３０は複数の部材からなり、軸線Ｏに沿って先端側から後端側へと延び、絶縁体１１を介して主体金具２０の内側に絶縁保持されている。導電体３０は、本実施形態では中心電極３１、端子金具３２及び抵抗体３３を備えている。 The conductor 30 is composed of a plurality of members, extends from the front end side to the rear end side along the axis O, and is insulated and held inside the main metal fitting 20 via the insulator 11. In this embodiment, the conductor 30 includes a center electrode 31, a terminal fitting 32, and a resistor 33.

中心電極３１は棒状の部材であり、銅製または銅合金製の芯材がニッケル又はニッケル基合金で覆われている。中心電極３１は、第２内周面１３と第３内周面１４との境界に係止され、絶縁体１１の先端から先端が露出する。中心電極３１は、接地電極２９と火花ギャップを介して対向する。端子金具３２は、高圧ケーブル（図示せず）が接続される棒状の部材であり、導電性を有する金属材料（例えば低炭素鋼等）によって形成されている。端子金具３２は、先端側が絶縁体１１の第２内周面１３の内側に挿入され、外周面が第１内周面１２から離間した状態で、絶縁体１１の後端に固定されている。 The center electrode 31 is a rod-shaped member, and a core material made of copper or a copper alloy is covered with nickel or a nickel-based alloy. The center electrode 31 is locked at the boundary between the second inner peripheral surface 13 and the third inner peripheral surface 14, and the tip is exposed from the tip of the insulator 11. The center electrode 31 faces the ground electrode 29 via a spark gap. The terminal fitting 32 is a rod-shaped member to which a high-voltage cable (not shown) is connected, and is made of a conductive metal material (for example, low carbon steel or the like). The terminal fitting 32 is fixed to the rear end of the insulator 11 with the tip end side inserted inside the second inner peripheral surface 13 of the insulator 11 and the outer peripheral surface separated from the first inner peripheral surface 12.

抵抗体３３は、スパーク時に発生する電波ノイズを抑えるための部材であり、第２内周面１３の内側に配置されている。抵抗体３３は、主成分であるガラス粒子、ガラス以外のセラミック粒子、及び、導電性材料を含む組成物で形成されている。第１接続部３４は、中心電極３１と抵抗体３３とを接続する導電性を有する部材である。第２接続部３５は、抵抗体３３と端子金具３２とを接続する導電性を有する部材である。第１接続部３４及び第２接続部３５によって中心電極３１、端子金具３２及び抵抗体３３が接続され、導電体３０が形成される。導電体３０はスパーク時に電流が流れる。 The resistor 33 is a member for suppressing radio wave noise generated at the time of sparking, and is arranged inside the second inner peripheral surface 13. The resistor 33 is formed of a composition containing glass particles as a main component, ceramic particles other than glass, and a conductive material. The first connecting portion 34 is a conductive member that connects the center electrode 31 and the resistor 33. The second connecting portion 35 is a conductive member that connects the resistor 33 and the terminal fitting 32. The center electrode 31, the terminal fitting 32, and the resistor 33 are connected by the first connecting portion 34 and the second connecting portion 35 to form the conductor 30. A current flows through the conductor 30 during sparking.

磁性体４０は、端子金具３２の周囲の第１内周面１２の内側に配置される部材である。磁性体４０は、初透磁率（以下「透磁率」と称す）の周波数特性が異なる磁性材料でそれぞれ形成される複数の磁性部材からなる。磁性体４０を構成する複数の磁性部材は、第１部材４１、第２部材４２及び第３部材４３を含んでいる。第１部材４１、第２部材４２及び第３部材４３は外径および内径が同一で、軸線方向の長さが異なる円筒状の部材である。本実施形態では第１部材４１の軸線方向の長さが最も長い。即ち第１部材４１の体積が最も大きい。 The magnetic body 40 is a member arranged inside the first inner peripheral surface 12 around the terminal fitting 32. The magnetic material 40 is composed of a plurality of magnetic members, each of which is made of a magnetic material having different frequency characteristics of initial magnetic permeability (hereinafter referred to as “magnetic permeability”). The plurality of magnetic members constituting the magnetic body 40 include a first member 41, a second member 42, and a third member 43. The first member 41, the second member 42, and the third member 43 are cylindrical members having the same outer diameter and inner diameter but different lengths in the axial direction. In the present embodiment, the length of the first member 41 in the axial direction is the longest. That is, the volume of the first member 41 is the largest.

第１部材４１、第２部材４２及び第３部材４３は、先端側から後端側へ第２部材４２、第１部材４１、第３部材４３の順に配置されている。第２部材４２は、先端側が、主体金具２０の後端２８よりも先端側に存在し、残りの部分が、主体金具２０の後端２８よりも後端側に存在する。第１部材４１及び第３部材４３は、全体が、主体金具２０の後端２８よりも後端側に存在する。第３部材４３は、主体金具２０の後端２８から最も離れた位置にある。 The first member 41, the second member 42, and the third member 43 are arranged in the order of the second member 42, the first member 41, and the third member 43 from the front end side to the rear end side. The front end side of the second member 42 is closer to the front end side than the rear end 28 of the main metal fitting 20, and the remaining portion is present on the rear end side of the rear end 28 of the main metal fitting 20. The first member 41 and the third member 43 as a whole exist on the rear end side of the rear end 28 of the main metal fitting 20. The third member 43 is located at the position farthest from the rear end 28 of the main metal fitting 20.

第１部材４１及び第２部材４２はＮｉ−Ｚｎフェライトで形成され、第３部材４３はＭｎ−Ｚｎフェライトで形成されている。第１部材４１と第２部材４２との間、及び、第１部材４１と第３部材４３との間には固定部材４４が介在する。固定部材４４は、第１部材４１、第２部材４２及び第３部材４３を互いに固定する。 The first member 41 and the second member 42 are made of Ni—Zn ferrite, and the third member 43 is made of Mn—Zn ferrite. A fixing member 44 is interposed between the first member 41 and the second member 42, and between the first member 41 and the third member 43. The fixing member 44 fixes the first member 41, the second member 42, and the third member 43 to each other.

固定部材４４は、例えば、第１部材４１、第２部材４２及び第３部材４３を互いに接着する接着剤、第１部材４１、第２部材４２及び第３部材４３の隙間に充填される充填材が挙げられる。固定部材４４は、各部材が対面する部位の全体に配置しても良いし、部分的に配置しても良い。固定部材４４は有機物、無機物を問わない。無機物の固定部材４４としては、ガラス、セメント等が挙げられる。固定部材４４が第１部材４１、第２部材４２及び第３部材４３を互いに固定すると、振動等による第１部材４１、第２部材４２及び第３部材４３の破損を抑制できる。 The fixing member 44 is, for example, an adhesive that adheres the first member 41, the second member 42, and the third member 43 to each other, and a filler that fills the gaps between the first member 41, the second member 42, and the third member 43. Can be mentioned. The fixing member 44 may be arranged over the entire portion where the members face each other, or may be partially arranged. The fixing member 44 may be an organic substance or an inorganic substance. Examples of the inorganic fixing member 44 include glass, cement and the like. When the fixing member 44 fixes the first member 41, the second member 42, and the third member 43 to each other, damage to the first member 41, the second member 42, and the third member 43 due to vibration or the like can be suppressed.

複数の磁性部材（第１部材４１、第２部材４２及び第３部材４３）は、主体金具２０の後端２８を境にして、後端２８よりも先端側に配置される先端部分４５と、後端２８よりも後端側に配置される後端部分４６と、に区分される。第２部材４２が先端部分４５を占め、第２部材４２、第１部材４１及び第３部材４３が後端部分４６に配置されている。第２部材４２が先端部分４５を占めるので、先端部分４５における第１部材４１の体積の割合は、第３部材４３の体積の割合と同じく０％である（即ち、第１部材４１の割合が最も小さい）。また、後端部分４６において第１部材４１の体積の割合は最も大きい。 The plurality of magnetic members (first member 41, second member 42, and third member 43) have a tip portion 45 arranged on the tip side of the rear end 28 with the rear end 28 of the main metal fitting 20 as a boundary. It is divided into a rear end portion 46 arranged on the rear end side of the rear end 28. The second member 42 occupies the tip portion 45, and the second member 42, the first member 41, and the third member 43 are arranged at the rear end portion 46. Since the second member 42 occupies the tip portion 45, the volume ratio of the first member 41 in the tip portion 45 is 0%, which is the same as the volume ratio of the third member 43 (that is, the ratio of the first member 41 is Smallest). Further, the volume ratio of the first member 41 is the largest in the rear end portion 46.

スパークプラグ１０は、例えば、以下のような方法によって製造される。まず、押出成形等によって第１部材４１及び第２部材４２の成形体を得た後、これらを焼成して第１部材４１、第２部材４２及び第３部材４３を得る。 The spark plug 10 is manufactured by, for example, the following method. First, a molded body of the first member 41 and the second member 42 is obtained by extrusion molding or the like, and then these are fired to obtain the first member 41, the second member 42, and the third member 43.

次に、絶縁体１１の後端側から中心電極３１を挿入し、中心電極３１を第２内周面１３と第３内周面１４との境界で係止する。次いで、第１接続部３４の原料粉末を中心電極３１の周りに充填した後、圧縮用棒材（図示せず）を用いて、第２内周面１３の内側に充填した第１接続部３４の原料粉末を予備圧縮する。 Next, the center electrode 31 is inserted from the rear end side of the insulator 11, and the center electrode 31 is locked at the boundary between the second inner peripheral surface 13 and the third inner peripheral surface 14. Next, the raw material powder of the first connection portion 34 is filled around the center electrode 31, and then the first connection portion 34 is filled inside the second inner peripheral surface 13 using a compression rod (not shown). Pre-compress the raw material powder.

次に、第２内周面１３の内側に抵抗体３３の原料粉末を供給して、第１接続部３４の原料粉末の上に抵抗体３３の原料粉末を充填する。圧縮用棒材（図示せず）を用いて、第２内周面１３の内側に充填した抵抗体３３の原料粉末を予備圧縮した後、第２内周面１３の内側に第２接続部３５の原料粉末を充填する。圧縮用棒材（図示せず）を用いて、第２内周面１３に充填した第２接続部３５の原料粉末を予備圧縮する。 Next, the raw material powder of the resistor 33 is supplied to the inside of the second inner peripheral surface 13, and the raw material powder of the resistor 33 is filled on the raw material powder of the first connection portion 34. After pre-compressing the raw material powder of the resistor 33 filled inside the second inner peripheral surface 13 using a compression rod (not shown), the second connecting portion 35 is inside the second inner peripheral surface 13. Fill with raw material powder. Using a compression rod (not shown), the raw material powder of the second connecting portion 35 filled in the second inner peripheral surface 13 is precompressed.

次いで、絶縁体１１の第１内周面１２の内側に第２部材４２、第１部材４１及び第３部材４３を順に挿入する。このときに各部材の間に固定部材４４を介在する。次に、絶縁体１１を炉内に移送し、例えば抵抗体３３、第１接続部３４及び第２接続部３５の各原料粉末に含まれるガラス成分の軟化点より高い温度まで加熱する。加熱後、第２部材４２、第１部材４１及び第３部材４３の内側に端子金具３２を挿入し、端子金具３２によって第２接続部３５の原料粉末を軸方向へ圧縮する。この結果、絶縁体１１の内部に抵抗体３３、第１接続部３４及び第２接続部３５が形成される。 Next, the second member 42, the first member 41, and the third member 43 are inserted in this order inside the first inner peripheral surface 12 of the insulator 11. At this time, a fixing member 44 is interposed between the members. Next, the insulator 11 is transferred into the furnace and heated to a temperature higher than the softening point of the glass component contained in each raw material powder of the resistor 33, the first connection portion 34 and the second connection portion 35, for example. After heating, the terminal fitting 32 is inserted inside the second member 42, the first member 41, and the third member 43, and the raw material powder of the second connecting portion 35 is axially compressed by the terminal fitting 32. As a result, the resistor 33, the first connecting portion 34, and the second connecting portion 35 are formed inside the insulator 11.

次に絶縁体１１を炉外へ移送し、予め接地電極２９が接合された主体金具２０を、絶縁体１１の外周に組み付ける。次いで、接地電極２９の先端が中心電極３１と対向するように接地電極２９を屈曲して、スパークプラグ１０を得る。 Next, the insulator 11 is transferred to the outside of the furnace, and the main metal fitting 20 to which the ground electrode 29 is bonded in advance is assembled to the outer periphery of the insulator 11. Next, the ground electrode 29 is bent so that the tip of the ground electrode 29 faces the center electrode 31 to obtain the spark plug 10.

図２は第１部材４１、第２部材４２及び第３部材４３を構成する磁性材料の周波数特性の模式図である。図２では横軸に周波数をとり、縦軸に透磁率をとる。μ′は複素透磁率の実数成分（インダクタンス成分）であり、μ″は複素透磁率の虚数成分（抵抗成分）である。μ′はある周波数まではほぼ一定の値をとるが、周波数が高くなると磁界の変化に磁束密度が追随できなくなり、位相の遅れが生じる。このため周波数の増加に伴いμ′が減少しμ″が増加する。第１部材４１、第２部材４２及び第３部材４３はμ′が低下し始める周波数の近くでμ″が最大ピークを示す。 FIG. 2 is a schematic diagram of the frequency characteristics of the magnetic materials constituting the first member 41, the second member 42, and the third member 43. In FIG. 2, the horizontal axis represents frequency and the vertical axis represents magnetic permeability. μ'is the real component (inductance component) of the complex permeability, μ ″ is the imaginary component (resistance component) of the complex permeability. Μ'takes an almost constant value up to a certain frequency, but the frequency is high. Then, the magnetic flux density cannot follow the change of the magnetic field, and the phase is delayed. Therefore, μ ′ decreases and μ ″ increases as the frequency increases. The first member 41, the second member 42, and the third member 43 show a maximum peak of μ ″ near the frequency at which μ ′ begins to decrease.

第１部材４１を構成する磁性材料（Ｎｉ−Ｚｎフェライト）の透磁率の最大ピークを示す周波数は最も高い。第２部材４２を構成する磁性材料（Ｎｉ−Ｚｎフェライト）の透磁率の最大ピークを示す周波数は２番目に高い。第３部材４３を構成する磁性材料（Ｍｎ−Ｚｎフェライト）の透磁率の最大ピークを示す周波数は最も低い。第１部材４１、第２部材４２及び第３部材４３はμ″が高い周波数で使われると、抵抗成分によってそれぞれその帯域のノイズを熱に変換し吸収する。 The frequency showing the maximum peak of the magnetic permeability of the magnetic material (Ni—Zn ferrite) constituting the first member 41 is the highest. The frequency showing the maximum peak of the magnetic permeability of the magnetic material (Ni—Zn ferrite) constituting the second member 42 is the second highest. The frequency showing the maximum peak of the magnetic permeability of the magnetic material (Mn—Zn ferrite) constituting the third member 43 is the lowest. When μ "is used at a high frequency, the first member 41, the second member 42, and the third member 43 each convert noise in the band into heat and absorb it by a resistance component.

なお、第１部材４１、第２部材４２及び第３部材４３の中で、第３部材４３の体積抵抗率が最も低く、第２部材４２の体積抵抗率が最も高い。体積抵抗率は直流４端子法によって測定された抵抗値に基づいて算出する値である。第１部材４１及び第２部材４２はＮｉ，Ｚｎの割合を異ならせること等により、透磁率の最大ピークを示す周波数および体積抵抗率が設定される。本実施形態では、第１部材４１の初透磁率は１２０、体積抵抗率は１×１０^５Ω・ｍであり、第２部材４２の初透磁率は１５００、体積抵抗率は１×１０^６Ω・ｍであり、第３部材４３の初透磁率は５０００、体積抵抗率は０．３Ω・ｍである。但し、これは一例であり、これに限られるものではない。 Among the first member 41, the second member 42, and the third member 43, the volume resistivity of the third member 43 is the lowest, and the volume resistivity of the second member 42 is the highest. The volume resistivity is a value calculated based on the resistance value measured by the DC 4-terminal method. The frequency and volume resistivity indicating the maximum peak of magnetic permeability are set in the first member 41 and the second member 42 by making the ratios of Ni and Zn different. In the present embodiment, the initial magnetic permeability of the first member 41 is 120 and the volume resistivity is 1 × 10 ⁵ Ω · m, the initial magnetic permeability of the second member 42 is 1500, and the volume resistivity is 1 × 10 ⁶ Ω. The initial magnetic permeability of the third member 43 is 5000, and the volume resistivity is 0.3Ω ・ m. However, this is an example and is not limited to this.

図１に戻って説明する。スパークプラグ１０は、透磁率の周波数特性が異なる第１部材４１、第２部材４２及び第３部材４３が導電体３０の周囲に配置されるので、スパーク時に導電体３０を電流が流れることによって生じる電波ノイズを広い周波数帯域において抑制できる。 It will be described back to FIG. Since the first member 41, the second member 42, and the third member 43 having different magnetic permeability frequency characteristics are arranged around the conductor 30, the spark plug 10 is generated by the current flowing through the conductor 30 during sparking. Radio noise can be suppressed in a wide frequency band.

スパークプラグ１０は、磁性部材の全体の体積に対する、透磁率の最大ピークを示す周波数が高い第１部材４１の体積の割合が最も大きい。第１部材４１の透磁率の最大ピークは他の第２部材４２及び第３部材４３の最大ピークに比べて低いが、第１部材４１の体積の割合を最も大きくすることにより、第２部材４２及び第３部材４３によるノイズ抑制に偏重しないように制御しながら、第１部材４１、第２部材４２及び第３部材４３を用いることで広くなったノイズ抑制可能な周波数帯域の全域で、十分なノイズ抑制効果を得ることができる。 In the spark plug 10, the ratio of the volume of the first member 41 having a high frequency indicating the maximum peak of magnetic permeability to the total volume of the magnetic member is the largest. The maximum peak of the magnetic permeability of the first member 41 is lower than the maximum peak of the other second member 42 and the third member 43, but by maximizing the volume ratio of the first member 41, the second member 42 And, while controlling so as not to overemphasize the noise suppression by the third member 43, the noise suppression possible frequency band widened by using the first member 41, the second member 42, and the third member 43 is sufficient. A noise suppression effect can be obtained.

ここで、主体金具２０の後端２８よりも先端側では、導電体３０を流れる電流の高周波成分の一部は主体金具２０を流れる。しかし、主体金具２０の後端２８よりも後端側では、電流の高周波成分のほぼ全てが導電体３０を流れる。従って、磁性材料の透磁率の最大ピークを示す周波数が高い第１部材４１の少なくとも一部を、主体金具２０の後端２８よりも後端側に配置することにより、導電体３０を流れる電流の高周波成分を抑制し易くできる。よって、ノイズの高周波成分を抑制し易くできる。 Here, on the tip side of the rear end 28 of the main metal fitting 20, a part of the high frequency component of the current flowing through the conductor 30 flows through the main metal fitting 20. However, on the rear end side of the main metal fitting 20 with respect to the rear end 28, almost all of the high frequency components of the current flow through the conductor 30. Therefore, by arranging at least a part of the first member 41 having a high frequency indicating the maximum peak of the magnetic permeability of the magnetic material on the rear end side of the rear end 28 of the main metal fitting 20, the current flowing through the conductor 30 can be measured. It is possible to easily suppress high frequency components. Therefore, it is possible to easily suppress the high frequency component of noise.

特に、第１部材４１は主体金具２０の後端２８よりも後端側に全体が配置されているので、第１部材４１の一部が後端２８よりも先端側に配置される場合に比べ、第１部材４１のうち電流の高周波成分の抑制に寄与する体積を最大にできる。一方、主体金具２０の後端２８よりも先端側に第１部材４１以外の磁性部材を配置できるので、第１部材４１以外の磁性部材によって、第１部材４１が抑制するノイズの帯域よりも低周波成分を抑制しつつ、第１部材４１による高周波成分の抑制効果を高めることができる。 In particular, since the first member 41 is entirely arranged on the rear end side of the main metal fitting 20 with respect to the rear end 28, compared with the case where a part of the first member 41 is arranged on the front end side of the rear end 28. , The volume of the first member 41 that contributes to suppressing the high frequency component of the current can be maximized. On the other hand, since a magnetic member other than the first member 41 can be arranged on the tip side of the rear end 28 of the main metal fitting 20, it is lower than the noise band suppressed by the first member 41 by the magnetic member other than the first member 41. While suppressing the frequency component, the effect of suppressing the high frequency component by the first member 41 can be enhanced.

なお、電流の低周波成分は、主体金具２０の存在に関わらずほぼ全てが導電体３０を流れる。そこで、先端部分４５における第１部材４１の体積の割合を最も小さくすることにより、第１部材４１以外の体積を相対的に大きくできる。その結果、先端部分４５に配置された第１部材４１以外の磁性部材によって、導電体３０を流れる電流のうち第１部材４１が抑制する周波数よりも低周波成分を抑制し易くできる。よって、ノイズの低周波成分を抑制し易くできる。 Almost all of the low-frequency components of the current flow through the conductor 30 regardless of the presence of the main metal fitting 20. Therefore, by making the ratio of the volume of the first member 41 in the tip portion 45 the smallest, the volume other than the first member 41 can be made relatively large. As a result, the magnetic members other than the first member 41 arranged at the tip portion 45 can easily suppress the low frequency component of the current flowing through the conductor 30 than the frequency suppressed by the first member 41. Therefore, it is possible to easily suppress the low frequency component of noise.

また、後端部分４６における第１部材４１の体積の割合を最も大きくすることにより、第１部材４１の体積を相対的に大きくできる。その結果、後端部分４６に配置された第１部材４１によって、導電体３０を流れる電流の高周波成分を抑制し易くできる。よって、ノイズの高周波成分を抑制し易くできる。 Further, the volume of the first member 41 can be made relatively large by maximizing the ratio of the volume of the first member 41 in the rear end portion 46. As a result, the first member 41 arranged at the rear end portion 46 can easily suppress the high frequency component of the current flowing through the conductor 30. Therefore, it is possible to easily suppress the high frequency component of noise.

体積抵抗率が最も低い第３部材４３の全体が、主体金具２０の後端２８よりも後端側に配置されるので、導電体３０と主体金具２０との間に磁性部材を介する貫通漏れ電流を生じ難くできる。よって、主体金具２０と導電体３０との間の絶縁性を確保できる。 Since the entire third member 43 having the lowest volume resistivity is arranged closer to the rear end side than the rear end 28 of the main metal fitting 20, a through leakage current via the magnetic member between the conductor 30 and the main metal fitting 20 Can be less likely to occur. Therefore, the insulating property between the main metal fitting 20 and the conductor 30 can be ensured.

なお、体積抵抗率が最も高い第２部材４２は、一部が主体金具２０の後端２８よりも先端側に配置されている。これにより、第２部材４２よりも体積抵抗率が低い第１部材４１が主体金具２０と導電体３０との間に配置される場合に比べ、主体金具２０と導電体３０との間の絶縁性を向上できる。さらに、第２部材４２は、先端側が、主体金具２０の後端２８よりも先端側に存在し、残りの部分が、主体金具２０の後端２８よりも後端側に存在する。主体金具２０の後端２８の前後に亘って第２部材４２が配置されているので、電界が集中し易い主体金具２０の後端２８と磁性体４０との間の貫通漏れ電流を生じ難くできる。その結果、主体金具２０と導電体３０との間の絶縁性をさらに向上できる。 A part of the second member 42 having the highest volume resistivity is arranged on the tip side of the rear end 28 of the main metal fitting 20. As a result, the insulating property between the main metal fitting 20 and the conductor 30 is higher than that in the case where the first member 41 having a volume resistivity lower than that of the second member 42 is arranged between the main metal fitting 20 and the conductor 30. Can be improved. Further, the front end side of the second member 42 is closer to the front end side than the rear end 28 of the main metal fitting 20, and the remaining portion is present on the rear end side of the rear end 28 of the main metal fitting 20. Since the second member 42 is arranged before and after the rear end 28 of the main metal fitting 20, it is possible to make it difficult to generate a through leakage current between the rear end 28 of the main metal fitting 20 and the magnetic body 40 where the electric field is easily concentrated. .. As a result, the insulating property between the main metal fitting 20 and the conductor 30 can be further improved.

Ｍｎ−Ｚｎフェライトにより形成される第３部材４３は、透磁率の最大ピークの周波数を低く、透磁率を高くすることができ、Ｎｉ−Ｚｎフェライトにより形成される第１部材４１及び第２部材４２は、第３部材４３に比べて透磁率は低いが、透磁率の最大ピークの周波数を高くできる。従って、これらのフェライトの組合せにより、各周波数帯域におけるノイズ抑制効果を制御しながら、広い周波数帯域でノイズ抑制効果を得ることができる。 The third member 43 formed of Mn—Zn ferrite can have a low maximum peak frequency of magnetic permeability and a high magnetic permeability, and the first member 41 and the second member 42 formed of Ni—Zn ferrite can be formed. Although the magnetic permeability is lower than that of the third member 43, the frequency of the maximum peak of the magnetic permeability can be increased. Therefore, by combining these ferrites, it is possible to obtain the noise suppression effect in a wide frequency band while controlling the noise suppression effect in each frequency band.

さらに、導電体３０の一部に抵抗体３３が配置されているので、導電体３０を流れる電流の低周波成分を抵抗体３３が熱に変換して吸収する。従って、磁性体４０によるノイズ減衰効果に加え、抵抗体３３によるノイズ減衰効果が得られる。 Further, since the resistor 33 is arranged in a part of the conductor 30, the resistor 33 converts the low frequency component of the current flowing through the conductor 30 into heat and absorbs it. Therefore, in addition to the noise attenuation effect of the magnetic material 40, the noise attenuation effect of the resistor 33 can be obtained.

図３を参照して第２実施の形態について説明する。第１実施形態では、主体金具２０の後端２８よりも先端側にも磁性部材が配置される場合について説明した。これに対し第２実施形態では、主体金具２０の後端２８よりも後端側だけに磁性部材が配置される場合について説明する。なお、第１実施形態で説明した部分と同一の部分については、同一の符号を付して以下の説明を省略する。図３は第２実施の形態におけるスパークプラグ５０の片側断面図である。なお、図３ではスパークプラグ５０の座部２４よりも先端側の図示が省略されている（図４及び図５においても同じ）。 The second embodiment will be described with reference to FIG. In the first embodiment, the case where the magnetic member is arranged on the tip side of the rear end 28 of the main metal fitting 20 has been described. On the other hand, in the second embodiment, the case where the magnetic member is arranged only on the rear end side of the rear end 28 of the main metal fitting 20 will be described. The same parts as those described in the first embodiment are designated by the same reference numerals, and the following description will be omitted. FIG. 3 is a one-sided sectional view of the spark plug 50 according to the second embodiment. In FIG. 3, the illustration of the tip side of the spark plug 50 with respect to the seat portion 24 is omitted (the same applies to FIGS. 4 and 5).

スパークプラグ５０の絶縁体５１は、後端側から先端側へ順に、第１内周面５２及び第２内周面１３が形成されている。第１内周面５２は第２内周面１３よりも内径が大きい。第１内周面５２と第２内周面１３との境界は、主体金具２０の後端２８よりも後端側に位置する。 The insulator 51 of the spark plug 50 is formed with a first inner peripheral surface 52 and a second inner peripheral surface 13 in this order from the rear end side to the front end side. The first inner peripheral surface 52 has a larger inner diameter than the second inner peripheral surface 13. The boundary between the first inner peripheral surface 52 and the second inner peripheral surface 13 is located on the rear end side of the rear end 28 of the main metal fitting 20.

磁性体５３は、端子金具３２の周囲の第１内周面５２の内側に配置されている。磁性体５３を構成する複数の磁性部材は、第１部材５４、第２部材５５及び第３部材５６を含んでいる。第１部材５４、第２部材５５及び第３部材５６は外径および内径が同一で、軸線方向の長さが異なる円筒状の部材である。本実施形態では第１部材５４の軸線方向の長さが最も長い。即ち第１部材５４の体積が最も大きい。 The magnetic body 53 is arranged inside the first inner peripheral surface 52 around the terminal fitting 32. The plurality of magnetic members constituting the magnetic body 53 include a first member 54, a second member 55, and a third member 56. The first member 54, the second member 55, and the third member 56 are cylindrical members having the same outer diameter and inner diameter but different lengths in the axial direction. In the present embodiment, the length of the first member 54 in the axial direction is the longest. That is, the volume of the first member 54 is the largest.

第１部材５４及び第２部材５５はＮｉ−Ｚｎフェライトで形成され、第３部材５６はＭｎ−Ｚｎフェライトで形成されている。第１部材５４、第２部材５５及び第３部材５６は固定部材４４（図１参照）により互いに固定されている。第１部材５４を構成する磁性材料の透磁率の最大ピークを示す周波数は最も高い。第２部材５５を構成する磁性材料の透磁率の最大ピークを示す周波数は２番目に高い。第３部材５６を構成する磁性材料の透磁率の最大ピークを示す周波数は最も低い。体積抵抗率は第３部材５６が最も低く、第２部材５５が最も高い。第１部材４１及び第２部材４２はＮｉ，Ｚｎの割合を異ならせること等により、透磁率の最大ピークを示す周波数および体積抵抗率が設定される。 The first member 54 and the second member 55 are made of Ni—Zn ferrite, and the third member 56 is made of Mn—Zn ferrite. The first member 54, the second member 55, and the third member 56 are fixed to each other by a fixing member 44 (see FIG. 1). The frequency indicating the maximum peak of the magnetic permeability of the magnetic material constituting the first member 54 is the highest. The frequency indicating the maximum peak of the magnetic permeability of the magnetic material constituting the second member 55 is the second highest. The frequency showing the maximum peak of the magnetic permeability of the magnetic material constituting the third member 56 is the lowest. The volume resistivity of the third member 56 is the lowest, and that of the second member 55 is the highest. The frequency and volume resistivity indicating the maximum peak of magnetic permeability are set in the first member 41 and the second member 42 by making the ratios of Ni and Zn different.

スパークプラグ５０によれば、主体金具２０の後端２８よりも後端側に第１部材５４及び第２部材５５を配置することにより、主体金具２０の後端２８よりも先端側に配置される磁性材料を省きつつ、導電体３０を流れる電流の高周波成分を抑制できる。さらに、主体金具２０の後端２８よりも後端側に第３部材５６を配置することにより、導電体３０を流れる電流の低周波成分を抑制しつつ、磁性体５３と主体金具２０との間に磁性部材を介する貫通漏れ電流を生じ難くできる。 According to the spark plug 50, by arranging the first member 54 and the second member 55 on the rear end side of the rear end 28 of the main metal fitting 20, the first member 54 and the second member 55 are arranged on the front end side of the rear end 28 of the main metal fitting 20. While omitting the magnetic material, the high frequency component of the current flowing through the conductor 30 can be suppressed. Further, by arranging the third member 56 on the rear end side of the main metal fitting 20 with respect to the rear end 28, the low frequency component of the current flowing through the conductor 30 is suppressed, and the space between the magnetic body 53 and the main metal fitting 20 is suppressed. It is possible to prevent a through leakage current from being generated through the magnetic member.

図４を参照して第３実施の形態について説明する。第１及び第２実施形態では、第１部材４１、第２部材４２及び第３部材４３が、径方向に重複しないで軸線方向に並ぶ場合について説明した。これに対し第３実施形態では、第１部材６２の一部の径方向の外側に第２部材６５が配置される場合について説明する。なお、第１実施形態および第２実施形態で説明した部分と同一の部分については、同一の符号を付して以下の説明を省略する。図４は第３実施の形態におけるスパークプラグ６０の片側断面図である。 The third embodiment will be described with reference to FIG. In the first and second embodiments, the case where the first member 41, the second member 42, and the third member 43 are arranged in the axial direction without overlapping in the radial direction has been described. On the other hand, in the third embodiment, a case where the second member 65 is arranged outside a part of the first member 62 in the radial direction will be described. The same parts as those described in the first embodiment and the second embodiment are designated by the same reference numerals, and the following description will be omitted. FIG. 4 is a one-sided sectional view of the spark plug 60 according to the third embodiment.

スパークプラグ６０に内蔵された磁性体６１は、端子金具３２の周囲の第１内周面５２の内側に配置されている。磁性体６１を構成する複数の磁性部材は第１部材６２及び第２部材６５を含んでいる。第１部材６２は、端子金具３２及び第１内周面５２に接触する円筒状の第１部６３と、第１部６３の後端の径方向の内側の部位から後端側に向かって突出する円筒状の第２部６４と、を備えている。第２部材６５は、第１部材６２の第１部６３の後端側かつ第２部６４の径方向の外側に配置される円筒状の部材である。 The magnetic body 61 built in the spark plug 60 is arranged inside the first inner peripheral surface 52 around the terminal fitting 32. The plurality of magnetic members constituting the magnetic body 61 include the first member 62 and the second member 65. The first member 62 projects toward the rear end side from the cylindrical first portion 63 that contacts the terminal fitting 32 and the first inner peripheral surface 52, and the radially inner portion of the rear end of the first portion 63. It is provided with a cylindrical second portion 64 and the like. The second member 65 is a cylindrical member arranged on the rear end side of the first part 63 of the first member 62 and on the outer side in the radial direction of the second part 64.

第１部材６２及び第２部材６５は主体金具２０の後端２８よりも後端側に全体が配置されている。第１部材６２の体積は第２部材６５の体積よりも大きい。第１部材６２及び第２部材６５は固定部材４４（図１参照）により互いに固定されている。 The first member 62 and the second member 65 are entirely arranged on the rear end side of the rear end 28 of the main metal fitting 20. The volume of the first member 62 is larger than the volume of the second member 65. The first member 62 and the second member 65 are fixed to each other by a fixing member 44 (see FIG. 1).

第１部材６２はＮｉ−Ｚｎフェライト製であり、第２部材６５はＭｎ−Ｚｎフェライト製である。第１部材６２の透磁率の最大ピークを示す周波数は、第２部材６５の透磁率の最大ピークを示す周波数よりも高い。一方、第２部材６５の体積抵抗率は第１部材６２の体積抵抗率よりも低い。 The first member 62 is made of Ni—Zn ferrite, and the second member 65 is made of Mn—Zn ferrite. The frequency indicating the maximum peak of the magnetic permeability of the first member 62 is higher than the frequency indicating the maximum peak of the magnetic permeability of the second member 65. On the other hand, the volume resistivity of the second member 65 is lower than the volume resistivity of the first member 62.

第１部材６２を構成する磁性材料の透磁率の最大ピークを示す周波数は、第２部材６５を構成する磁性材料の透磁率の最大ピークを示す周波数よりも高いので、第１部材６２の透磁率の最大ピークは第２部材６５の透磁率の最大ピークより低い（図２参照）。よって、第２部材６５よりも透磁率の最大ピークを示す周波数が高い第１部材６２を、第２部材６５よりも導電体３０の近くに配置することで、ノイズ抑制が低周波成分に偏らないように制御しながら、複数の磁性部材を用いることで広くなったノイズ抑制可能な周波数帯域の全域で、十分なノイズ抑制効果を得ることができる。 Since the frequency indicating the maximum peak of the magnetic permeability of the magnetic material constituting the first member 62 is higher than the frequency indicating the maximum peak of the magnetic permeability of the magnetic material constituting the second member 65, the magnetic permeability of the first member 62 The maximum peak of is lower than the maximum peak of the magnetic permeability of the second member 65 (see FIG. 2). Therefore, by arranging the first member 62, which has a higher frequency showing the maximum peak of magnetic permeability than the second member 65, closer to the conductor 30 than the second member 65, the noise suppression is not biased to the low frequency component. By using a plurality of magnetic members while controlling the noise, a sufficient noise suppression effect can be obtained in the entire frequency band in which the noise can be suppressed.

図５（ａ）を参照して第４実施の形態について説明する。第３実施形態では、磁性体が２つの磁性部材（第１部材６２及び第２部材６５）からなる場合について説明した。これに対し第４実施形態では、磁性体６１が３つの磁性部材からなる場合について説明する。なお、第１実施形態で説明した部分と同一の部分については、同一の符号を付して以下の説明を省略する。図５（ａ）は第４実施の形態におけるスパークプラグ７０の片側断面図である。 The fourth embodiment will be described with reference to FIG. 5 (a). In the third embodiment, the case where the magnetic material is composed of two magnetic members (first member 62 and second member 65) has been described. On the other hand, in the fourth embodiment, the case where the magnetic body 61 is composed of three magnetic members will be described. The same parts as those described in the first embodiment are designated by the same reference numerals, and the following description will be omitted. FIG. 5A is a one-sided sectional view of the spark plug 70 according to the fourth embodiment.

スパークプラグ７０に内蔵された磁性体７１は、端子金具３２の周囲の第１内周面１２の内側に配置されている。磁性体７１を構成する複数の磁性部材は、円筒状に形成された第１部材７２、第２部材７８及び第３部材８２を含んでいる。第１部材７２及び第２部材７８はＮｉ−Ｚｎフェライト製であり、第３部材８２はＭｎ−Ｚｎフェライト製である。透磁率の最大ピークを示す周波数は、第１部材７２、第２部材７８、第３部材８２の順に高い。体積抵抗率は第３部材８２が最も低い。第１部材７２の体積は、第１部材７２、第２部材７８及び第３部材８２の中で最も大きい。第１部材７２、第２部材７８及び第３部材８２は固定部材４４（図１参照）により互いに固定されている。 The magnetic body 71 built in the spark plug 70 is arranged inside the first inner peripheral surface 12 around the terminal fitting 32. The plurality of magnetic members constituting the magnetic body 71 include a first member 72, a second member 78, and a third member 82 formed in a cylindrical shape. The first member 72 and the second member 78 are made of Ni—Zn ferrite, and the third member 82 is made of Mn—Zn ferrite. The frequency showing the maximum peak of magnetic permeability is higher in the order of the first member 72, the second member 78, and the third member 82. The third member 82 has the lowest volume resistivity. The volume of the first member 72 is the largest among the first member 72, the second member 78, and the third member 82. The first member 72, the second member 78, and the third member 82 are fixed to each other by a fixing member 44 (see FIG. 1).

第１部材７２及び第２部材７８はＮｉ，Ｚｎの割合を異ならせること等により、透磁率の最大ピークを示す周波数および体積抵抗率が設定される。本実施形態では、第１実施形態と同様に、第１部材７２の初透磁率は１２０、体積抵抗率は１×１０^５Ω・ｍであり、第２部材７８の初透磁率は１５００、体積抵抗率は１×１０^６Ω・ｍであり、第３部材８２の初透磁率は５０００、体積抵抗率は０．３Ω・ｍである。但し、これは一例であり、これに限られるものではない。 The frequency and volume resistivity indicating the maximum peak of magnetic permeability are set in the first member 72 and the second member 78 by changing the ratios of Ni and Zn. In this embodiment, like the first embodiment, the initial permeability of the first member 72 is 120, the volume resistivity thereof was 1 × 10 ⁵ Ω · m, initial permeability of the second member 78 is 1500, volume The resistivity is 1 × 10 ⁶ Ω · m, the initial magnetic permeability of the third member 82 is 5000, and the volume resistivity is 0.3 Ω · m. However, this is an example and is not limited to this.

第１部材７２は、端子金具３２及び第１内周面１２に接触する円筒状の第１部７３と、第１部７３の先端の径方向の内側の部位から先端側に向かって突出する円筒状の第２部７４と、第１部７３の後端の径方向の内側の部位から後端側に向かって突出する円筒状の第３部７５と、を備えている。第２部材７８に接触する第１部材７２の接触面７６には、第１部７３と第２部７４との段差によって凹凸が形成される。第３部材８２に接触する第１部材７２の接触面７７には、第１部７３と第３部７５との段差によって凹凸が形成される。 The first member 72 is a cylindrical first portion 73 that contacts the terminal fitting 32 and the first inner peripheral surface 12, and a cylinder that projects toward the tip side from a radially inner portion of the tip of the first portion 73. A second portion 74 having a shape and a cylindrical third portion 75 projecting from a radially inner portion of the rear end of the first portion 73 toward the rear end side are provided. The contact surface 76 of the first member 72, which comes into contact with the second member 78, has irregularities formed by the step between the first portion 73 and the second portion 74. The contact surface 77 of the first member 72, which comes into contact with the third member 82, has irregularities formed by the step between the first portion 73 and the third portion 75.

第２部材７８は、端子金具３２及び第１内周面１２に接触する円筒状の第１部７９と、第１部７９の後端の径方向の外側の部位から後端側に向かって突出する円筒状の第２部８０と、を備えている。第２部材７８の第２部８０は、第１部材７２の第２部７４の径方向の外側に配置される。第１部材７２に接触する第２部材７８の接触面８１には、第１部７９と第２部８０との段差によって凹凸が形成される。 The second member 78 projects from the cylindrical first portion 79 in contact with the terminal fitting 32 and the first inner peripheral surface 12 and the radially outer portion of the rear end of the first portion 79 toward the rear end side. It is provided with a cylindrical second portion 80 and the like. The second part 80 of the second member 78 is arranged outside the second part 74 of the first member 72 in the radial direction. The contact surface 81 of the second member 78, which is in contact with the first member 72, is formed with irregularities due to the step between the first portion 79 and the second portion 80.

第３部材８２は、端子金具３２及び第１内周面１２に接触する円筒状の第１部８３と、第１部８３の先端の径方向の外側の部位から先端側に向かって突出する円筒状の第２部８４と、を備えている。第３部材８２の第２部８４は、第１部材７２の第３部７５の径方向の外側に配置される。第１部材７２に接触する第３部材８２の接触面８５には、第１部８３と第２部８４との段差によって凹凸が形成される。 The third member 82 is a cylindrical first portion 83 that contacts the terminal fitting 32 and the first inner peripheral surface 12, and a cylinder that projects toward the tip side from a radially outer portion of the tip of the first portion 83. The second part 84 of the shape and the like are provided. The second part 84 of the third member 82 is arranged outside the third part 75 of the first member 72 in the radial direction. The contact surface 85 of the third member 82, which is in contact with the first member 72, is formed with irregularities due to the step between the first portion 83 and the second portion 84.

磁性体７１は、主体金具２０の後端２８を境にして、後端２８よりも先端側に配置される先端部分８６と、後端２８よりも後端側に配置される後端部分８７と、に区分される。第２部材７８が先端部分８６を占め、第２部材７８、第１部材７２及び第３部材８２が後端部分８７に配置されている。第２部材７８が先端部分８６を占めるので、先端部分８６における第１部材７２の体積の割合は第３部材８２の体積の割合と同じく０％である（即ち、第１部材７２の割合が最も小さい）。また、後端部分８７において第１部材７２の体積の割合は最も大きい。 The magnetic body 71 includes a front end portion 86 arranged on the front end side of the rear end 28 and a rear end portion 87 arranged on the rear end side of the rear end 28 with the rear end 28 of the main metal fitting 20 as a boundary. It is divided into. The second member 78 occupies the tip portion 86, and the second member 78, the first member 72, and the third member 82 are arranged at the rear end portion 87. Since the second member 78 occupies the tip portion 86, the volume ratio of the first member 72 in the tip portion 86 is 0%, which is the same as the volume ratio of the third member 82 (that is, the ratio of the first member 72 is the highest). small). Further, the volume ratio of the first member 72 is the largest in the rear end portion 87.

第１部材７２の第２部７４は第２部材７８の第２部８０に比べて導電体３０に近いので、導電体３０に電流が流れることによって生じる磁界の影響を受け易い。よって、第１部材７２の第２部７４によるノイズ抑制効果を発現し易くできる。同様に、第１部材７２の第３部７５は第３部材８２の第２部８４に比べて導電体３０に近いので、導電体３０に電流が流れることによって生じる磁界の影響を受け易くできる。よって、第１部材７２による高周波成分のノイズ抑制効果を発現し易くできる。これにより、第２部材７８や第３部材８２によるノイズ抑制に偏重するのを防ぎ、第１部材７２、第２部材７８及び第３部材８２による広帯域のノイズ抑制効果が得られる。 Since the second part 74 of the first member 72 is closer to the conductor 30 than the second part 80 of the second member 78, it is easily affected by the magnetic field generated by the current flowing through the conductor 30. Therefore, the noise suppression effect of the second part 74 of the first member 72 can be easily exhibited. Similarly, since the third part 75 of the first member 72 is closer to the conductor 30 than the second part 84 of the third member 82, it can be easily affected by the magnetic field generated by the current flowing through the conductor 30. Therefore, the noise suppression effect of the high frequency component by the first member 72 can be easily exhibited. This prevents the noise suppression by the second member 78 and the third member 82 from being overemphasized, and the wideband noise suppression effect by the first member 72, the second member 78, and the third member 82 can be obtained.

第２部材７８の第２部８０は第１部材７２の第２部７４に比べて導電体３０から遠いが、第２部材７８の透磁率の最大ピークは第１部材７２の透磁率の最大ピークに比べて大きいので、導電体３０から離れていても第２部材７８によるノイズ抑制効果は確保できる。同様に、第３部材８２の第２部８４は第１部材７２の第３部７５に比べて導電体３０から遠いが、第３部材８２の透磁率の最大ピークは第１部材７２の透磁率の最大ピークに比べて大きいので、第３部材８２によるノイズ抑制効果を確保できる。これにより、第２部材７８や第３部材８２によるノイズ抑制に偏重するのを防ぎ、第１部材７２、第２部材７８及び第３部材８２による広帯域のノイズ抑制効果が得られる。 The second part 80 of the second member 78 is farther from the conductor 30 than the second part 74 of the first member 72, but the maximum peak of the magnetic permeability of the second member 78 is the maximum peak of the magnetic permeability of the first member 72. Therefore, the noise suppression effect of the second member 78 can be ensured even if the conductor is separated from the conductor 30. Similarly, the second part 84 of the third member 82 is farther from the conductor 30 than the third part 75 of the first member 72, but the maximum peak of the magnetic permeability of the third member 82 is the magnetic permeability of the first member 72. Since it is larger than the maximum peak of, the noise suppression effect of the third member 82 can be ensured. This prevents the noise suppression by the second member 78 and the third member 82 from being overemphasized, and the wideband noise suppression effect by the first member 72, the second member 78, and the third member 82 can be obtained.

第１部材７２及び第２部材７８の接触面７６，８１に、互いに合わさる凹凸が形成されているので、第１部材７２及び第２部材７８の位置を径方向へずれ難くできる。その結果、振動等による第１部材７２及び第２部材７８の破損を抑制できる。同様に、第１部材７２及び第３部材８２の接触面７７，８５に、互いに合わさる凹凸が形成されているので、第１部材７２及び第３部材８２の位置を径方向へずれ難くできる。その結果、振動等による第１部材７２及び第３部材８２の破損を抑制できる。 Since the contact surfaces 76 and 81 of the first member 72 and the second member 78 are formed with irregularities that meet each other, the positions of the first member 72 and the second member 78 can be prevented from shifting in the radial direction. As a result, damage to the first member 72 and the second member 78 due to vibration or the like can be suppressed. Similarly, since the contact surfaces 77 and 85 of the first member 72 and the third member 82 are formed with irregularities that meet each other, the positions of the first member 72 and the third member 82 can be prevented from shifting in the radial direction. As a result, damage to the first member 72 and the third member 82 due to vibration or the like can be suppressed.

図５（ｂ）を参照して第５実施の形態について説明する。第４実施形態では、第１部材７２の接触面７７の一部が第３部材８２の接触面８５の一部の径方向の内側に位置する場合、第２部材７８の接触面８１の一部が第１部材７２の接触面７６の一部の径方向の外側に位置する場合について説明した。これに対し第５実施形態では、第２部材７８の接触面９４の一部が第１部材７２の接触面９２の径方向の中央に位置する場合について説明する。なお、第１実施形態および第４実施形態において説明した部分と同一の部分については、同一の符号を付して以下の説明を省略する。図５（ｂ）は第５実施の形態におけるスパークプラグ９０の断面図である。図５（ｂ）では軸線Ｏを境にした片側の図示が省略されている。 The fifth embodiment will be described with reference to FIG. 5 (b). In the fourth embodiment, when a part of the contact surface 77 of the first member 72 is located inside a part of the contact surface 85 of the third member 82 in the radial direction, a part of the contact surface 81 of the second member 78. Has been described when is located outside a part of the contact surface 76 of the first member 72 in the radial direction. On the other hand, in the fifth embodiment, a case where a part of the contact surface 94 of the second member 78 is located at the center of the contact surface 92 of the first member 72 in the radial direction will be described. The same parts as those described in the first embodiment and the fourth embodiment are designated by the same reference numerals, and the following description will be omitted. FIG. 5B is a cross-sectional view of the spark plug 90 according to the fifth embodiment. In FIG. 5B, the illustration on one side of the axis O is omitted.

スパークプラグ９０の第１部材７２は、第１部７３の先端の径方向の内側および外側の部位から先端側へそれぞれ突出する円筒状の第２部９１を備えている。第２部材７８に接触する第１部材７２の接触面９２には、第１部７３と第２部９１との段差によって凹凸が形成される。第２部材７８は、第１部７９の後端の径方向の中央の部位から後端側へ突出する円筒状の第２部９３を備えている。第２部材７８の第２部９３は、第１部材７２の第２部９１の間に配置される。第１部材７２に接触する第２部材７８の接触面９４には、第１部７９と第２部９３との段差によって凹凸が形成される。接触面９２，９４の凹凸が互いに径方向に接触することにより、第１部材７２及び第２部材７８の径方向の移動が規制される。その結果、第１部材７２及び第２部材７８を径方向にずれ難くできるので、振動等による第１部材７２及び第２部材７８の破損を抑制できる。 The first member 72 of the spark plug 90 includes a cylindrical second portion 91 that projects from the radially inner and outer portions of the tip of the first portion 73 toward the tip side, respectively. The contact surface 92 of the first member 72, which comes into contact with the second member 78, has irregularities formed by the step between the first portion 73 and the second portion 91. The second member 78 includes a cylindrical second portion 93 that projects from the radial center portion of the rear end of the first portion 79 toward the rear end side. The second part 93 of the second member 78 is arranged between the second parts 91 of the first member 72. The contact surface 94 of the second member 78, which comes into contact with the first member 72, has irregularities formed by the step between the first portion 79 and the second portion 93. When the irregularities of the contact surfaces 92 and 94 come into contact with each other in the radial direction, the movement of the first member 72 and the second member 78 in the radial direction is restricted. As a result, the first member 72 and the second member 78 can be prevented from being displaced in the radial direction, so that damage to the first member 72 and the second member 78 due to vibration or the like can be suppressed.

以上、実施の形態に基づき本発明を説明したが、本発明は上記実施の形態に何ら限定されるものではなく、本発明の趣旨を逸脱しない範囲内で種々の改良変形が可能であることは容易に推察できるものである。 Although the present invention has been described above based on the embodiments, the present invention is not limited to the above embodiments, and various improvements and modifications can be made without departing from the spirit of the present invention. It can be easily inferred.

第３実施形態では磁性体６１は２個の磁性部材からなり、その他の実施形態では磁性体は３個の磁性部材からなる場合について説明したが、必ずしもこれに限られるものではない。磁性体を構成する磁性部材の数は２個以上（例えば４個や５個など）を適宜設定できる。 In the third embodiment, the case where the magnetic material 61 is composed of two magnetic members and in the other embodiments, the magnetic material is composed of three magnetic members has been described, but the present invention is not necessarily limited to this. The number of magnetic members constituting the magnetic material can be appropriately set to 2 or more (for example, 4 or 5).

実施形態では導電体３０に内蔵する抵抗体３３が、絶縁体１１の内部で原料粉末を成形して焼成するモノリシックタイプの場合について説明したが、必ずしもこれに限られるものではない。予め製造された抵抗器を絶縁体１１に挿入して抵抗体とすることは当然可能である。また、当然のことながら抵抗体は省略できる。 In the embodiment, the case where the resistor 33 built in the conductor 30 is a monolithic type in which the raw material powder is molded and fired inside the insulator 11 has been described, but the present invention is not necessarily limited to this. Of course, it is possible to insert a prefabricated resistor into the insulator 11 to form a resistor. Also, as a matter of course, the resistor can be omitted.

実施形態では、第２接続部３５が原料粉末を焼成して形成される場合について説明したが、必ずしもこれに限られるものではない。導電性のあるばね等の弾性体により第２接続部３５を形成することは当然可能である。 In the embodiment, the case where the second connecting portion 35 is formed by firing the raw material powder has been described, but the present invention is not necessarily limited to this. Of course, it is possible to form the second connecting portion 35 with an elastic body such as a conductive spring.

実施形態では、絶縁体１１，５１の第１内周面１２，５２の内径を第２内周面１３の内径よりも大きくして、第１内周面１２，５２と端子金具３２との隙間に磁性体４０，５３，６１，７１を設ける場合について説明したが、必ずしもこれに限られるものではない。例えば、第１内周面１２，５２の内径を第２内周面１３の内径と同じ大きさにする一方、端子金具３２を細くして、第１内周面１２，５２と端子金具３２との間に隙間を作り、その隙間に磁性体を設けることは当然可能である。 In the embodiment, the inner diameter of the first inner peripheral surfaces 12, 52 of the insulators 11, 51 is made larger than the inner diameter of the second inner peripheral surface 13, and the gap between the first inner peripheral surfaces 12, 52 and the terminal fitting 32 is set. Although the case where the magnetic materials 40, 53, 61, and 71 are provided in the above is described, the present invention is not necessarily limited to this. For example, while making the inner diameters of the first inner peripheral surfaces 12 and 52 the same as the inner diameter of the second inner peripheral surface 13, the terminal metal fittings 32 are thinned to form the first inner peripheral surfaces 12 and 52 and the terminal metal fittings 32. Of course, it is possible to create a gap between the two and provide a magnetic material in the gap.

第１、第２、第４及び第５実施形態では、軸線方向の先端側から順に第２部材、第１部材、第３部材が配置される場合について説明したが、必ずしもこれに限られるものではない。透磁率の最大ピークを示す周波数が最も高い第１部材の体積と磁性部材の全体の体積との関係（第１部材の体積が最も大きい）を維持したまま、これらの部材を任意の順番に並べ替えることは当然可能である。体積が最も大きい第１部材によって、ノイズの高周波成分を抑制できるからである。 In the first, second, fourth, and fifth embodiments, the case where the second member, the first member, and the third member are arranged in order from the tip side in the axial direction has been described, but the present invention is not necessarily limited to this. Absent. Arrange these members in any order while maintaining the relationship between the volume of the first member having the highest frequency showing the maximum peak of magnetic permeability and the total volume of the magnetic member (the volume of the first member is the largest). Of course, it is possible to change it. This is because the high frequency component of noise can be suppressed by the first member having the largest volume.

第１及び第５実施形態では、体積抵抗率が最も小さい第３部材４３，８２を、主体金具２０の後端２８から最も離れた位置に配置する場合について説明したが、必ずしもこれに限られるものではない。第３部材４３，８２の位置を第１部材４１，７２と入れ替えることは当然可能である。第１部材４１，７２と第３部材４３，８２とを入れ替えても、主体金具２０の後端２８よりも後端側に、体積抵抗率の最も小さい第３部材４３，８２の全体を配置できるので、磁性体と主体金具２０との間に貫通漏れ電流を生じ難くできるからである。 In the first and fifth embodiments, the case where the third members 43 and 82 having the smallest volume resistivity are arranged at the position farthest from the rear end 28 of the main metal fitting 20 has been described, but the present invention is not necessarily limited to this. is not it. Of course, it is possible to replace the positions of the third members 43 and 82 with those of the first members 41 and 72. Even if the first members 41 and 72 and the third members 43 and 82 are replaced, the entire third member 43 and 82 having the smallest volume resistivity can be arranged on the rear end side of the main metal fitting 20 with respect to the rear end 28. Therefore, it is possible to prevent a through leakage current from being generated between the magnetic material and the main metal fitting 20.

第２実施形態では、体積抵抗率が最も小さい第３部材５６を、主体金具２０の後端２８から最も離れた位置に配置し、第３実施形態では、体積抵抗率が最も小さい第２部材６５を、第１部材６２の第１部６３よりも後端側に配置した。しかし、必ずしもこれに限られるものではない。第３部材５６や第２部材６５は、絶縁体５１の第１内周面５２の内側の任意の位置に配置できる。第１内周面５２と第２内周面１３との境界は主体金具２０の後端２８よりも後端側にあるので、第３部材５６や第２部材６５を第１内周面５２の内側のどこに配置しても、主体金具２０の後端２８よりも後端側に、第３部材５６や第２部材６５の全体を配置できるからである。 In the second embodiment, the third member 56 having the smallest volume resistivity is arranged at a position farthest from the rear end 28 of the main metal fitting 20, and in the third embodiment, the second member 65 having the smallest volume resistivity. Was arranged on the rear end side of the first member 62 with respect to the first portion 63. However, it is not always limited to this. The third member 56 and the second member 65 can be arranged at arbitrary positions inside the first inner peripheral surface 52 of the insulator 51. Since the boundary between the first inner peripheral surface 52 and the second inner peripheral surface 13 is on the rear end side of the rear end 28 of the main metal fitting 20, the third member 56 and the second member 65 are placed on the first inner peripheral surface 52. This is because the entire third member 56 and the second member 65 can be arranged on the rear end side of the main metal fitting 20 with respect to the rear end 28 regardless of where it is arranged on the inside.

実施形態では、固定部材４４によって磁性部材が互いに固定される場合について説明したが、必ずしもこれに限られるものではない。固定部材４４を省略することは当然可能である。 In the embodiment, the case where the magnetic members are fixed to each other by the fixing member 44 has been described, but the present invention is not necessarily limited to this. Of course, it is possible to omit the fixing member 44.

実施形態では、磁性体４０，５３，６１，７１が端子金具３０の周囲に配置される場合について説明したが、必ずしもこれに限られるものではない。中心電極３１や抵抗体３３等の周囲に磁性体を配置することは当然可能である。端子金具３０と同様に、中心電極３１や抵抗体３３等もスパーク時に電流が流れるので、磁性体によるノイズ抑制効果が得られるからである。 In the embodiment, the case where the magnetic bodies 40, 53, 61, and 71 are arranged around the terminal fitting 30 has been described, but the present invention is not necessarily limited to this. Of course, it is possible to arrange a magnetic material around the center electrode 31, the resistor 33, and the like. This is because, similarly to the terminal metal fitting 30, the center electrode 31, the resistor 33, and the like also have a noise suppression effect due to the magnetic material because a current flows during sparking.

１０，５０，６０，７０，９０スパークプラグ
２０主体金具
２８主体金具の後端
３０導電体
４０，５３，６１，７１磁性体
４１，５４，６２，７２第１部材（磁性部材、透磁率の最大ピークを示す周波数が最も高い部材）
４２，５５，６５，７８第２部材（磁性部材）
４３，５６，８２第３部材（磁性部材、体積抵抗率が最も小さい部材）
４４固定部材
４５，８６先端部分
４６，８７後端部分 10, 50, 60, 70, 90 Spark plug 20 Main metal fittings 28 Rear end of main metal fittings 30 Conductor 40, 53, 61, 71 Magnetic material 41, 54, 62, 72 First member (magnetic member, maximum magnetic permeability) The member with the highest peak frequency)
42, 55, 65, 78 Second member (magnetic member)
43, 56, 82 Third member (magnetic member, member with the lowest volume resistivity)
44 Fixing member 45,86 Tip part 46,87 Rear end part

Claims

円筒状の主体金具と、
前記主体金具の内側に絶縁保持され先端側から後端側へと軸線方向に延びる導電体と、
前記導電体の周囲に配置される磁性体と、を備えるスパークプラグであって、
前記磁性体は、透磁率の周波数特性が異なる磁性材料でそれぞれ形成される複数の磁性部材を備え、
前記複数の磁性部材は、前記複数の磁性部材の全体の体積に対する、前記複数の磁性部材のうち前記磁性材料の透磁率の最大ピークを示す周波数が最も高い部材の体積の割合が最も大きいスパークプラグ。 Cylindrical main metal fittings and
A conductor that is insulated and held inside the main metal fitting and extends in the axial direction from the front end side to the rear end side,
A spark plug comprising a magnetic material arranged around the conductor.
The magnetic material includes a plurality of magnetic members each formed of a magnetic material having a different frequency characteristic of magnetic permeability.
The plurality of magnetic members are spark plugs in which the ratio of the volume of the member having the highest frequency indicating the maximum peak of the magnetic permeability of the magnetic material among the plurality of magnetic members to the total volume of the plurality of magnetic members is the largest. ..

前記複数の磁性部材のうち、前記磁性材料の透磁率の最大ピークを示す周波数が最も高い部材の少なくとも一部は、前記主体金具の後端よりも後端側に配置される請求項１記載のスパークプラグ。 The first aspect of claim 1, wherein at least a part of the members having the highest frequency showing the maximum peak of the magnetic permeability of the magnetic material among the plurality of magnetic members is arranged on the rear end side of the main metal fitting. Spark plug.

前記複数の磁性部材のうち前記主体金具の後端よりも先端側に配置される先端部分は、前記複数の磁性部材のうち前記磁性材料の透磁率の最大ピークを示す周波数が最も高い部材の体積の割合が最も小さい請求項１又は２に記載のスパークプラグ。 The tip portion of the plurality of magnetic members arranged closer to the tip side than the rear end of the main metal fitting is the volume of the member having the highest frequency indicating the maximum peak of the magnetic permeability of the magnetic material among the plurality of magnetic members. The spark plug according to claim 1 or 2, which has the smallest proportion of.

前記複数の磁性部材のうち前記主体金具の後端よりも後端側に配置される後端部分は、前記複数の磁性部材のうち前記磁性材料の透磁率の最大ピークを示す周波数が最も高い部材の体積の割合が最も大きい請求項１から３のいずれかに記載のスパークプラグ。 Among the plurality of magnetic members, the rear end portion arranged on the rear end side of the main metal fitting is the member having the highest frequency indicating the maximum peak of the magnetic permeability of the magnetic material among the plurality of magnetic members. The spark plug according to any one of claims 1 to 3, which has the largest volume ratio of.

前記複数の磁性部材は、第１部材と、自身の少なくとも一部が前記第１部材の少なくとも一部よりも径方向の外側に配置される第２部材と、を含み、
前記第１部材を構成する磁性材料の透磁率の最大ピークを示す周波数は、前記第２部材を構成する磁性材料の透磁率の最大ピークを示す周波数よりも高い請求項１から４のいずれかに記載のスパークプラグ。 The plurality of magnetic members include a first member and a second member in which at least a part of itself is arranged radially outside of at least a part of the first member.
The frequency indicating the maximum peak of the magnetic permeability of the magnetic material constituting the first member is higher than the frequency indicating the maximum peak of the magnetic permeability of the magnetic material constituting the second member according to any one of claims 1 to 4. Described spark plug.

前記軸線方向に延びる軸孔を有し前記主体金具に外周側から保持される絶縁体を備え、
前記磁性体は、前記導電体の周囲であって前記軸孔の内部に配置され、
前記磁性体の一部は、前記主体金具の後端よりも先端側に配置され、
前記複数の磁性部材のうち体積抵抗率が最も低い部材は、前記部材の全体が、前記主体金具の後端よりも後端側に配置される請求項１から５のいずれかに記載のスパークプラグ。 The main metal fitting has an insulator that has a shaft hole extending in the axial direction and is held from the outer peripheral side.
The magnetic material is arranged around the conductor and inside the shaft hole.
A part of the magnetic material is arranged closer to the tip side than the rear end of the main metal fitting.
The spark plug according to any one of claims 1 to 5, wherein the member having the lowest volume resistivity among the plurality of magnetic members is such that the entire member is arranged on the rear end side of the main metal fitting. ..

軸線方向に互いに接する接触面を有する前記複数の磁性部材は、互いに合わさる凹凸が前記接触面に形成されている請求項６記載のスパークプラグ。 The spark plug according to claim 6, wherein the plurality of magnetic members having contact surfaces that are in contact with each other in the axial direction have irregularities that are formed on the contact surfaces so as to meet each other.

前記複数の磁性部材は、固定部材を介して互いに固定されている請求項１から７のいずれかに記載のスパークプラグ。 The spark plug according to any one of claims 1 to 7, wherein the plurality of magnetic members are fixed to each other via a fixing member.

前記磁性材料は、Ｍｎ−Ｚｎフェライト及びＮｉ−Ｚｎフェライトを含有する請求項１から８のいずれかに記載のスパークプラグ。 The spark plug according to any one of claims 1 to 8, wherein the magnetic material contains Mn-Zn ferrite and Ni-Zn ferrite.