JP5010959B2 - Ignition coil for internal combustion engine and method for manufacturing the same - Google Patents

Ignition coil for internal combustion engine and method for manufacturing the same Download PDF

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JP5010959B2
JP5010959B2 JP2007096991A JP2007096991A JP5010959B2 JP 5010959 B2 JP5010959 B2 JP 5010959B2 JP 2007096991 A JP2007096991 A JP 2007096991A JP 2007096991 A JP2007096991 A JP 2007096991A JP 5010959 B2 JP5010959 B2 JP 5010959B2
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cross
sectional area
yoke portion
gap
internal combustion
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JP2008258291A (en
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貴信 小林
洋一 安蔵
康則 大高
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Hitachi Astemo Ltd
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Hitachi Automotive Systems Ltd
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本発明は内燃機関の点火プラグに火花放電を発生させるために高電圧を供給する内燃機関用点火コイルに関し、ことに主継鉄部と、この主継鉄部に並行に配置された側継鉄部と、主継鉄部の両端を側継鉄部と連結する一対の連結継鉄部からなる閉磁路を有し、主継鉄部の周りに一次，二次コイルからなる点火コイルが装着されているタイプの内燃機関用点火コイルに関する。   The present invention relates to an ignition coil for an internal combustion engine that supplies a high voltage to generate a spark discharge in an ignition plug of the internal combustion engine, and in particular, a main yoke portion and a side yoke arranged in parallel to the main yoke portion. And a closed magnetic path consisting of a pair of connecting yokes connecting both ends of the main yoke with the side yoke, and ignition coils consisting of primary and secondary coils are mounted around the main yoke. It relates to an ignition coil for an internal combustion engine of the type.

従来の内燃機関用点火コイルはドイツ特許第３４２８７６３号公報の第７図あるいは、特開昭５９−７８５１６号公報（ＵＳＰ４３５７８７号明細書）に示すように、閉磁路を形成するように主継鉄部と、その主継鉄部に並行に配置された側継鉄部と、主継鉄部の両端を側継鉄部と連結する一対の連結継鉄部が設けられている。   As shown in FIG. 7 of German Patent No. 3428763 or Japanese Patent Laid-Open No. 59-78516 (USP 435787), a conventional ignition coil for an internal combustion engine has a main yoke portion so as to form a closed magnetic circuit. And the side yoke part arrange | positioned in parallel with the main yoke part, and a pair of connection yoke part which connects the both ends of a main yoke part with a side yoke part are provided.

また、主継鉄部の外周には、バッテリに接続された一次巻線を一次ボビンに巻回して構成された一次コイルが装着されている。   Moreover, the primary coil comprised by winding the primary winding connected to the battery around the primary bobbin is attached to the outer periphery of the main yoke part.

その一次コイルの外周には、プラグに接続された二次巻線を二次ボビンに巻回して構成された二次コイルが装着されている。   A secondary coil constituted by winding a secondary winding connected to a plug around a secondary bobbin is mounted on the outer periphery of the primary coil.

そして、これらはコイルケース内に収納され、コイルケース内には絶縁用樹脂を注入して絶縁されている。   These are housed in a coil case, and are insulated by injecting an insulating resin into the coil case.

上記主継鉄部の片端には連結継鉄部との間に空隙部が設けられている。   A gap is provided between one end of the main yoke portion and the connecting yoke portion.

ドイツ特許第３４２８７６３号公報German Patent No. 3428763 特開昭５９−７８５１６号公報（ＵＳＰ４３５７８７号明細書）JP 59-78516 A (USP 435787 specification)

このような内燃機関用点火コイルにおいてさらに出力エネルギを増大させるためには、継鉄部の断面積を拡大させるもしくは一次コイル巻数を増大させる必要がある。しかしこれらの手法では点火コイル外形の大型化という問題を有している。   In order to further increase the output energy in such an ignition coil for an internal combustion engine, it is necessary to increase the cross-sectional area of the yoke portion or increase the number of turns of the primary coil. However, these methods have the problem of increasing the size of the ignition coil.

また単に巻数を増大したり、供給電力を高くしても主継鉄部が磁束飽和を起すとそれ以上磁束は流れなくなる。   Even if the number of turns is simply increased or the supply power is increased, if the main yoke portion saturates the magnetic flux, no further magnetic flux flows.

本発明の目的は、点火コイル外形を大型化させずに出力エネルギを増大させることのできる内燃機関用点火コイルを提供することにある。具体的には、主継鉄部が局部的な磁気飽和を起し難くするものである。   An object of the present invention is to provide an ignition coil for an internal combustion engine that can increase output energy without enlarging the outer shape of the ignition coil. Specifically, the main yoke part is difficult to cause local magnetic saturation.

上記目的を達成するために本発明では、コイルが装着された主継鉄部の一端と連結継鉄部の一方との間に空隙部が設けられており、主継鉄部は空隙部に近い部分の断面積より反空隙側の断面積が大きく形成されている。   In order to achieve the above object, in the present invention, a gap is provided between one end of the main yoke portion to which the coil is attached and one of the connecting yoke portions, and the main yoke portion is close to the gap portion. The cross-sectional area on the side opposite to the gap is formed larger than the cross-sectional area of the portion.

本発明によれば、点火コイル外形を拡大せずに、出力エネルギを増大させることができる。   According to the present invention, the output energy can be increased without enlarging the outer shape of the ignition coil.

以下図面に示す実施例に基づき本発明を詳説する。   The present invention will be described in detail below based on embodiments shown in the drawings.

図１，図２には、本発明に係る内燃機関用点火コイルの一実施例が示されている。図１は内燃機関用点火コイルの断面構成図、図２は図１に図示の内燃機関用点火コイルのＸ−Ｘ線断面図である。   1 and 2 show an embodiment of an ignition coil for an internal combustion engine according to the present invention. FIG. 1 is a cross-sectional view of an internal combustion engine ignition coil, and FIG. 2 is a cross-sectional view of the internal combustion engine ignition coil shown in FIG.

図１において、内燃機関用点火コイル１は、内燃機関の各シリンダのプラグホールに装着されて点火プラグに直結し使用される独立点火形の内燃機関用点火コイルである。この内燃機関用点火コイル１は、継鉄部６を有し、この継鉄部６は、図２に示す如く、中心に太い主継鉄部６Ａを備え、その両側に主継鉄部の約１／２の幅の側継鉄部６Ｄ１，６Ｄ２を備える。これら３本の継鉄部は両端が連結継鉄部６Ｂ１，６Ｂ２により連結され結果的に側継鉄部と連結系鉄部は矩形の継鉄部を形成している。主継鉄部の一端には連結継鉄部６Ｂ１との間に空隙が形成されている。   In FIG. 1, an internal combustion engine ignition coil 1 is an independent ignition internal combustion engine ignition coil that is attached to a plug hole of each cylinder of an internal combustion engine and is directly connected to the ignition plug. The ignition coil 1 for an internal combustion engine has a yoke portion 6, which has a thick main yoke portion 6A at the center as shown in FIG. Side yoke portions 6D1 and 6D2 having a width of 1/2 are provided. Both ends of these three yoke portions are connected by connecting yoke portions 6B1 and 6B2, and as a result, the side yoke portion and the connecting system iron portion form a rectangular yoke portion. A gap is formed between one end of the main yoke portion and the connecting yoke portion 6B1.

主継鉄部の周りにはバッテリに接続された一次巻線を一次ボビンに巻回して構成された一次コイルが装着されている。   Around the main yoke portion, a primary coil configured by winding a primary winding connected to a battery around a primary bobbin is mounted.

その一次コイルの外周には、プラグに接続された二次巻線を二次ボビンに巻回して構成された二次コイルが装着されている。   A secondary coil constituted by winding a secondary winding connected to a plug around a secondary bobbin is mounted on the outer periphery of the primary coil.

そして、これらはコイルケース７内に収納され、コイルケース７内には絶縁用樹脂１０が注入され内部が絶縁されている。   And these are accommodated in the coil case 7, and the resin 10 for insulation is inject | poured in the coil case 7, and the inside is insulated.

上記主継鉄部６Ａの片端には連結継鉄部６Ｂ１との間に空隙部が設けられている。   A gap is provided between one end of the main yoke portion 6A and the connecting yoke portion 6B1.

一般には図２の破線で示す連結継鉄部６Ｂ１と側継鉄部６Ｄ１，６Ｄ２との繋がり部で、例えば特開昭５９−７８５１６号公報（ＵＳＰ４３５７８７号明細書）に示すように継鉄部が分離形成されており、主継鉄部に、コイルを装着した後、両継鉄部を接合している。この分離する場所はいくつかの例があり、例えばドイツ特許第３４２８７６３号公報に示されるように、図７に示されるような分離の方法もある。   In general, the connecting portion between the connecting yoke portion 6B1 and the side yoke portions 6D1 and 6D2 indicated by the broken line in FIG. 2, for example, as shown in JP-A-59-78516 (USP 435787), It is formed separately, and after the coil is attached to the main yoke part, both yoke parts are joined. There are several examples of this separation place. For example, as shown in German Patent No. 3428763, there is also a separation method as shown in FIG.

この継鉄部６は、０.２〜０.７mmの珪素鋼板をプレス積層して閉磁路をなす磁路を形成している。そして、この継鉄部６は、主継鉄部６Ａと、側継鉄部６Ｄ１，６Ｄ２、連結継鉄部６Ｂ１，６Ｂ２とによって構成されている。この側継鉄部６Ｄ，連結継鉄部６Ｂ全体は、図２に示す如く、矩形の枠状に形成され、閉磁路を形成している。   This yoke part 6 forms a magnetic path that forms a closed magnetic path by press laminating 0.2 to 0.7 mm of a silicon steel plate. And this yoke part 6 is comprised by 6 A of main yoke parts, side yoke parts 6D1 and 6D2, and connection yoke parts 6B1 and 6B2. As shown in FIG. 2, the side yoke portion 6D and the entire connecting yoke portion 6B are formed in a rectangular frame shape to form a closed magnetic circuit.

そして、この主継鉄部６Ａは、図２に示す如く、一端が矩形の枠状に形成される連結継鉄部６Ｂの一側６Ｂ２に固着され、他端が矩形の枠状に形成される連結継鉄部６Ｂの他側６Ｂ１と空隙部６Ｃを隔てて対面している。この主継鉄部６Ａは、図１に示す如く、一次ボビン２に収納されている。この継鉄部６の外周側に配設され主継鉄部６Ａが収納されている一次ボビン２は、熱可塑性合成樹脂により形成されている。この一次ボビン２の上には、一次巻線３Ａが巻回され、一次巻線３Ａが形成されている。この一次巻線３Ａは、線径０.３〜１.０mm程度のエナメル線を一層当たり数十回ずつ、数層にわたり合計百ないし三百回程度一次ボビン２に積層巻されて形成されている。   As shown in FIG. 2, the main yoke portion 6A is fixed to one side 6B2 of one end of the connecting yoke portion 6B formed in a rectangular frame shape, and the other end is formed in a rectangular frame shape. The other side 6B1 of the connecting yoke 6B faces the gap 6C. The main yoke portion 6A is accommodated in the primary bobbin 2 as shown in FIG. The primary bobbin 2 disposed on the outer peripheral side of the yoke portion 6 and housing the main yoke portion 6A is formed of a thermoplastic synthetic resin. On the primary bobbin 2, a primary winding 3A is wound to form a primary winding 3A. The primary winding 3A is formed by laminating and winding an enameled wire having a wire diameter of about 0.3 to 1.0 mm on the primary bobbin 2 several tens of times per layer for a total of about 100 to 300 times. .

また、この一次巻線３Ａの外周には、空隙をもって、二次ボビン４が配設されている。この二次ボビン４は、一次ボビン２と同様に熱可塑性合成樹脂によって成形されており、この二次ボビン４には複数個の巻溝４Ａが形成されている。この二次ボビン４の上には、二次巻線５Ａが巻装され、二次コイル５を形成している。この二次巻線５Ａは、線径0.03〜０.１mm 程度のエナメル線を用いて合計五千ないし三万回程度二次ボビン４の巻溝４Ａに分割巻されて形成されている。このように、一次ボビン２は、二次ボビン４の内側に挿入された状態となっている。また、矩形の枠状に形成される連結継鉄部６Ｂ２側に固着される主継鉄部６Ａの他端と、連結継鉄部６Ｂ１との間の空隙部６Ｃには、一次巻線３Ａの通電によって継鉄部６を励磁する方向と逆方向に磁化された図示していない永久磁石を挿入してもよい。この一次ボビン２に一次巻線３Ａを巻回して構成された一次コイル３，二次ボビン４に二次巻線５Ａを巻回して構成した二次コイル５、及び継鉄部６は、コイルケース７に収納されている。   Further, a secondary bobbin 4 is disposed around the outer periphery of the primary winding 3A with a gap. The secondary bobbin 4 is formed of a thermoplastic synthetic resin in the same manner as the primary bobbin 2, and a plurality of winding grooves 4 </ b> A are formed on the secondary bobbin 4. A secondary winding 5 </ b> A is wound on the secondary bobbin 4 to form a secondary coil 5. The secondary winding 5A is formed by being divided and wound into the winding groove 4A of the secondary bobbin 4 by a total of about 5,000 to 30,000 times using an enameled wire having a wire diameter of about 0.03 to 0.1 mm. As described above, the primary bobbin 2 is inserted inside the secondary bobbin 4. Further, the gap 6C between the other end of the main yoke portion 6A fixed to the connecting yoke portion 6B2 formed in a rectangular frame shape and the connecting yoke portion 6B1 has a primary winding 3A. You may insert the permanent magnet which is magnetized in the reverse direction to the direction which excites the yoke part 6 by electricity supply. The primary coil 3 formed by winding the primary winding 3A around the primary bobbin 2, the secondary coil 5 formed by winding the secondary winding 5A around the secondary bobbin 4, and the yoke portion 6 are coil cases. 7.

また、一次巻線３Ａに供給する電力は、端子８及び巻線端８Ａを介して供給され、この端子８には、図示していないが、外部コネクタが接続されるようになっている。一方、二次コイル５には、高圧端子９が接続されている。この二次コイル５には、一次巻線３Ａの通電によって点火プラグに火花放電を発生させるための高電圧が誘起される。この二次コイル５に誘起された高電圧は、高圧端子９を介して点火プラグに供給され、この二次コイル５に誘起された高電圧の供給を受け、点火プラグは、火花放電を発生させる。   The power supplied to the primary winding 3A is supplied via the terminal 8 and the winding end 8A. The terminal 8 is connected to an external connector (not shown). On the other hand, a high voltage terminal 9 is connected to the secondary coil 5. The secondary coil 5 is induced with a high voltage for generating a spark discharge in the spark plug by energization of the primary winding 3A. The high voltage induced in the secondary coil 5 is supplied to the spark plug via the high voltage terminal 9, and the spark plug generates a spark discharge upon receiving the high voltage induced in the secondary coil 5. .

そして、この一次ボビン２に巻装された一次巻線３Ａ，二次ボビン４に巻装された二次巻線５Ａ及び継鉄部６が収容されているコイルケース７には、熱硬化性樹脂材である絶縁用樹脂（具体的には、エポキシ樹脂）１０が封入されている。この絶縁用樹脂１０は、コイルケース７の内側と、一次ボビン２に巻装された一次巻線３Ａ，二次ボビン４に巻装された二次巻線５Ａとの隙間に充填され、この絶縁用樹脂１０を硬化させて一次巻線３Ａ，二次巻線５Ａとの絶縁を行っている。このようにコイルケース７内には、この絶縁用樹脂（具体的には、エポキシ樹脂）１０によって一次巻線３Ａ，二次巻線５Ａ，一次ボビン２，二次ボビン４が絶縁され、固定されて一体化して収容されている。   The coil case 7 in which the primary winding 3A wound around the primary bobbin 2 and the secondary winding 5A wound around the secondary bobbin 4 and the yoke portion 6 are accommodated is provided with a thermosetting resin. An insulating resin (specifically, an epoxy resin) 10 that is a material is enclosed. This insulating resin 10 is filled in a gap between the inside of the coil case 7 and the primary winding 3A wound around the primary bobbin 2 and the secondary winding 5A wound around the secondary bobbin 4. The resin 10 is cured to insulate the primary winding 3A and the secondary winding 5A. Thus, the primary winding 3A, the secondary winding 5A, the primary bobbin 2, and the secondary bobbin 4 are insulated and fixed in the coil case 7 by the insulating resin (specifically, epoxy resin) 10. Are integrated and housed.

継鉄部６には、図３（ａ）に示す如きＥ字状に形成されるものと、図３（ｂ）に示す如きＣ字状に形成されるものとがある。そして、継鉄部６は、一次巻線３Ａに通電することによって継鉄部６が励磁され、図３（ａ）に示す如きＥ字状に形成される継鉄部６の場合は、磁束の流れが図５（ａ）に示す如くなる。また、図３（ｂ）に示す如きＣ字状に形成される継鉄部６の場合は、磁束の流れが図５（ｂ）に示す如くなる。   The yoke portion 6 includes a portion formed in an E shape as shown in FIG. 3A and a portion formed in a C shape as shown in FIG. The yoke portion 6 is excited by energizing the primary winding 3A, and in the case of the yoke portion 6 formed in an E shape as shown in FIG. The flow is as shown in FIG. Moreover, in the case of the yoke part 6 formed in C shape as shown in FIG.3 (b), the flow of magnetic flux becomes as shown in FIG.5 (b).

次に継鉄部６の形状について説明する。通常主継鉄部６Ａの形状は図４に示す如くストレート形状とし断面積はどこの位置でも均一に形成することが一般的である。ところが、主継鉄部６Ａの片端に空隙部６Ｃを設けた継鉄部の場合、一次コイルの通電によって励磁された継鉄部の磁束密度は位置により異なる。図６に一次電流を通電した際にＥ字状に形成された継鉄部６に発生する磁束密度分布を磁場解析によって計算した結果を、図５(ａ)に一次電流を通電した際にＥ字状に形成された継鉄部６に発生した磁束の流れを示す。このように空隙部６Ｃ近傍の主継鉄部６Ａの磁束密度は空隙部６Ｃ反対側の主継鉄部６Ａの磁束密度に比べて約６０％しか発生していない。さらに空隙部６Ｃ反対側の主継鉄部６Ａでは珪素鋼板の飽和磁束密度（約１.６Ｔ〜２.０Ｔ）まで磁束密度が高くなっており、このように局部的に継鉄部６が磁気飽和していると継鉄部６全体に発生する磁束量は低減してしまう。   Next, the shape of the yoke part 6 will be described. Usually, the shape of the main yoke portion 6A is a straight shape as shown in FIG. 4, and the cross-sectional area is generally formed uniformly at any position. However, in the case of a yoke part provided with a gap 6C at one end of the main yoke part 6A, the magnetic flux density of the yoke part excited by energization of the primary coil differs depending on the position. The magnetic flux density distribution generated in the yoke portion 6 formed in an E shape when the primary current is applied in FIG. 6 is calculated by the magnetic field analysis. The result of FIG. The flow of the magnetic flux which generate | occur | produced in the yoke part 6 formed in the letter shape is shown. As described above, the magnetic flux density of the main yoke portion 6A in the vicinity of the gap portion 6C is generated only about 60% as compared with the magnetic flux density of the main yoke portion 6A on the opposite side of the gap portion 6C. Further, in the main yoke portion 6A on the opposite side to the gap portion 6C, the magnetic flux density is increased to the saturation magnetic flux density (about 1.6 T to 2.0 T) of the silicon steel plate, and thus the yoke portion 6 is locally magnetized. If saturated, the amount of magnetic flux generated in the entire yoke portion 6 is reduced.

これは空隙部６Ｃの磁気抵抗が継鉄部材料である珪素鋼板の１００倍以上大きく、その影響により通常磁束は継鉄部６内を流れるのに対し、磁束が継鉄部６内を通らずに空隙部
６Ｃで磁束が漏洩し、連結継鉄部６Ｂから主継鉄部６Ａに短絡して流れている。このため、空隙部６Ｃ近傍の主継鉄部６Ａの磁束密度に対し空隙部６Ｃ反対側の主継鉄部６Ａの磁束密度が大きくなるのである。したがって、通常ストレート形状である主継鉄部６Ａは磁束密度分布の違いから、本来必要断面積は形成位置によって異なり、さらに出力エネルギをＵＰさせるには空隙部６Ｃ反対側の主継鉄部６Ａの断面積を拡大させることが有効である。 This is because the magnetic resistance of the gap 6C is more than 100 times that of the silicon steel plate material, and the magnetic flux normally flows in the yoke 6 due to the influence, but the magnetic flux does not pass through the yoke 6. The magnetic flux leaks in the gap portion 6C, and flows from the connecting yoke portion 6B to the main yoke portion 6A. For this reason, the magnetic flux density of the main yoke portion 6A on the opposite side of the gap portion 6C is larger than the magnetic flux density of the main yoke portion 6A near the gap portion 6C. Therefore, the main yoke portion 6A, which is normally straight, has a necessary cross-sectional area that varies depending on the position of formation due to the difference in magnetic flux density distribution. It is effective to enlarge the cross-sectional area.

また、一次巻線３Ａを一次ボビン２に巻回する場合、数層重ねて巻回するが通常の点火コイル１は図７（ａ）に示すように始めの一層目は一次ボビン２の巻線部全体を利用し巻回を行い、上層になると一次巻線３Ａの巻数と一次ボビン２の巻線部との全長の関係、一次巻線３Ａを接続する端子８との位置関係から一次ボビン２全体に巻回するのではなく、一次ボビン２の空隙側に巻線部全体の約１／３〜２／３程度の部分に一次巻線３Ａを２乃至３段余計に重ね巻きすることで、磁気飽和しにくい空隙部側に巻線を多く巻回し、磁気飽和しやすい反空隙側の巻線の巻数を少なくすることで、主継鉄部全体として見たときに磁気飽和しにくい構成とすることができる。   Further, when the primary winding 3A is wound around the primary bobbin 2, several layers are wound, but the normal ignition coil 1 is the winding of the primary bobbin 2 as shown in FIG. The primary bobbin 2 is wound based on the relationship between the number of turns of the primary winding 3A and the total length of the winding portion of the primary bobbin 2 and the positional relationship with the terminal 8 connecting the primary winding 3A. By winding the primary winding 3A on the gap side of the primary bobbin 2 over about 1/3 to 2/3 of the primary bobbin 2 over two or three stages, By winding many windings on the gap side where magnetic saturation is difficult and reducing the number of windings on the non-gap side where magnetic saturation is likely to occur, it is difficult to cause magnetic saturation when viewed as the main yoke part as a whole. be able to.

図１，図２，図７（ａ），図８及び図８に示す実施例においては、一次コイル３の巻線が巻かれていない空間部を有効利用するために一次ボビン２の形状を変更し、また一次巻線３Ａの巻回方法を図７（ｂ）に示す如く変更している。   In the embodiment shown in FIG. 1, FIG. 2, FIG. 7 (a), FIG. 8 and FIG. 8, the shape of the primary bobbin 2 is changed in order to effectively use the space where the winding of the primary coil 3 is not wound. In addition, the winding method of the primary winding 3A is changed as shown in FIG.

具体的には一次巻線３Ａを巻回しない空間を上層に設けるのではなく、始めの一層目，二層目の一次コイル巻数を少なくさせることで主継鉄部６Ａ側に空間を配設する。ここで設ける空間は一次巻線３Ａを巻回した一次ボビン２を主継鉄部６Ａに配設した時に継鉄部６の空隙部６Ｃに対し反対側の内側に一次巻線３Ａを巻回しない空間が形成されるように一次ボビン２の巻線部を段付形状とする。このように空間を設けることで主継鉄部６Ａの空隙部６Ｃ反対側に空間ができ、主継鉄部６Ａの断面積をこの部分において部分的に拡大させることが可能となる。   Specifically, the space for winding the primary winding 3A is not provided in the upper layer, but the space is arranged on the main yoke portion 6A side by reducing the number of primary coil turns in the first and second layers. . The space provided here does not wind the primary winding 3A inside the opposite side to the gap 6C of the yoke portion 6 when the primary bobbin 2 around which the primary winding 3A is wound is disposed on the main yoke portion 6A. The winding part of the primary bobbin 2 is formed in a stepped shape so that a space is formed. By providing a space in this way, a space is created on the opposite side of the gap portion 6C of the main yoke portion 6A, and the cross-sectional area of the main yoke portion 6A can be partially enlarged in this portion.

ここで上記のように主継鉄部６Ａの空隙部６Ｃの反対側の断面積を拡大させた場合、一次電流を通電した際に継鉄部６に発生する磁束密度分布を磁場解析によって計算した結果を図８に示す。   Here, when the cross-sectional area of the main yoke portion 6A opposite to the gap portion 6C is enlarged as described above, the magnetic flux density distribution generated in the yoke portion 6 when the primary current is applied is calculated by magnetic field analysis. The results are shown in FIG.

図６に示す一般的な点火コイル１では空隙部６Ｃ反対側の主継鉄部６Ａでは磁気飽和していたが、図８に示すように本実施例においては空隙部６Ｃ反対側の主継鉄部６Ａの断面積を拡大させることでその箇所では磁気飽和していないことが確認できる。   In the general ignition coil 1 shown in FIG. 6, the main yoke portion 6A on the opposite side of the gap portion 6C was magnetically saturated, but in this embodiment, as shown in FIG. 8, the main yoke on the opposite side of the gap portion 6C. By enlarging the cross-sectional area of the portion 6A, it can be confirmed that the portion is not magnetically saturated.

さらに主継鉄部６Ａの形状を通常のストレート形状にした場合と本実施例のように空隙部６Ｃ反対側の断面積を拡大させた場合の出力エネルギを求めてみる。この出力エネルギの算出方法は、図９に示す斜線部Ｓの面積を求めることにより算出することができ、具体的には、磁場解析により数式１に示す演算式を用いて計算する。   Furthermore, the output energy when the shape of the main yoke portion 6A is a normal straight shape and when the cross-sectional area on the opposite side of the gap portion 6C is enlarged as in this embodiment will be obtained. The calculation method of the output energy can be calculated by obtaining the area of the shaded portion S shown in FIG. 9, and specifically, the calculation is performed using the arithmetic expression shown in Expression 1 by the magnetic field analysis.

Figure 0005010959
Figure 0005010959

計算を行うと出力エネルギＷは主継鉄部６Ａを通常のストレート形状にした場合に対し約８％程度出力が大きくなっていた。また、実測においても磁場解析と同様の結果が得られた。このように出力が大きくなった理由として以下のことから説明ができる。   As a result of the calculation, the output energy W is about 8% higher than the case where the main yoke portion 6A is made into a normal straight shape. In the actual measurement, the same result as the magnetic field analysis was obtained. The reason why the output is increased in this way can be explained from the following.

数式１において一次巻線３Ａの磁束Φは数式２に示す関係がある。   In Formula 1, the magnetic flux Φ of the primary winding 3A has the relationship shown in Formula 2.

Figure 0005010959
Figure 0005010959

さらに数式２において磁気抵抗は数式３に示す関係がある。   Further, in Equation 2, the magnetoresistance has the relationship shown in Equation 3.

Figure 0005010959
Figure 0005010959

この数式３は磁路内の平均透磁率，磁路長を用いるが、実際には空隙部があるために磁気抵抗Ｑが磁路内で一定ではなく、磁気抵抗Ｑは以下の数式４に示す関係がある。   This mathematical formula 3 uses the average magnetic permeability and magnetic path length in the magnetic path, but since the magnetic resistance Q is actually not constant in the magnetic path due to the presence of the air gap, the magnetic resistance Q is expressed by the following mathematical formula 4. There is a relationship.

Figure 0005010959
Figure 0005010959

また、図１０に一般的な珪素鋼板の磁気特性を示す。   FIG. 10 shows the magnetic characteristics of a general silicon steel sheet.

ここで例えば一次巻線３Ａに通電させたときに数式４の第三項目の部分が磁気飽和していると仮定した場合、磁気飽和している箇所では図１０に示すようにμ3 の透磁率は
０.００１ 以下と小さく磁気抵抗Ｑは大きくなる。そこでこの磁気飽和している箇所の断面積Ｓ3 を拡大させると、磁気飽和が緩和され、透磁率μ3 も約５倍程度大きくなる。したがって、磁気飽和している箇所の継鉄部６の断面積を拡大させることで断面積Ｓ3 が大、透磁率μ3 が大、となることから磁気抵抗Ｑを小さくさせることができ、一次巻線３Ａの磁束Φを拡大させ、出力エネルギＷをＵＰさせることが可能となる。 Here, for example, when it is assumed that the portion of the third item of Formula 4 is magnetically saturated when the primary winding 3A is energized, the magnetic permeability of μ 3 is obtained at the magnetically saturated portion as shown in FIG. Is as small as 0.001 or less and the magnetoresistance Q is large. Therefore, when the cross-sectional area S 3 of the magnetically saturated portion is increased, the magnetic saturation is relaxed and the magnetic permeability μ 3 is increased by about 5 times. Therefore, by enlarging the cross-sectional area of the yoke portion 6 where the magnetic saturation occurs, the cross-sectional area S 3 becomes large and the magnetic permeability μ 3 becomes large. It is possible to increase the output energy W by increasing the magnetic flux Φ of the winding 3A.

一次巻線３Ａの巻回方法を上記のように変更し、主継鉄部を拡大させたことで出力エネルギが約８％向上しており、これは通常の点火コイル１において、継鉄部６の断面積を変えずに一次巻線３Ａの巻数だけ増やした場合、一次巻線３Ａの巻数を約２０％巻足した点火コイル１の出力と同等である。しかし、一次巻線３Ａを２０％巻足す場合には一次コイル抵抗が増大となり、点火コイル１の発熱が懸念されるため、一次巻線３Ａの線径を大きくする必要があり、結局点火コイル１の平面投影面積が拡大してしまう。また、一次巻線３Ａの巻数の増加に伴い、二次巻線５Ａの巻数も増加させる必要があり、さらなる点火コイル１の形状拡大、また、一次巻線３Ａ，二次巻線５Ａの巻数増大によるコストの増加が考えられる。一方、本実施例における点火コイル１では点火コイル外形の拡大，点火コイル１のコスト増大をせずに出力エネルギを約８％向上させることが可能となる。さらに一次ボビン２及び主継鉄部６Ａに段付形状を設けたことで、一次ボビン２を主継鉄部６Ａに配設する場合に挿入方向をすぐに判断することができ、誤組の防止にもなる。   By changing the winding method of the primary winding 3A as described above and enlarging the main yoke part, the output energy is improved by about 8%. When the number of turns of the primary winding 3A is increased without changing the cross-sectional area, the output is equivalent to the output of the ignition coil 1 obtained by adding about 20% of the number of turns of the primary winding 3A. However, when 20% of the primary winding 3A is added, the primary coil resistance increases, and there is a concern about the heat generation of the ignition coil 1. Therefore, it is necessary to increase the wire diameter of the primary winding 3A. The plane projection area will be enlarged. Further, as the number of turns of the primary winding 3A increases, it is necessary to increase the number of turns of the secondary winding 5A, and further increase the shape of the ignition coil 1, and increase the number of turns of the primary winding 3A and the secondary winding 5A. The cost can be increased by On the other hand, in the ignition coil 1 in the present embodiment, it is possible to improve the output energy by about 8% without enlarging the outer shape of the ignition coil and increasing the cost of the ignition coil 1. Further, by providing the primary bobbin 2 and the main yoke portion 6A with a stepped shape, when the primary bobbin 2 is arranged on the main yoke portion 6A, the insertion direction can be determined immediately, and erroneous assembly is prevented. It also becomes.

次に主継鉄部６Ａの拡大部の必要幅について説明する。主継鉄部６Ａの拡大幅は図１１に示すような関係がある。図１１は磁場解析により計算した結果であり、空隙部反対側の主継鉄部６Ａの幅を徐々に広げていった時の空隙部６Ｃ側の主継鉄部６Ａに対する主継鉄部６Ａ拡大幅（％）と出力エネルギの関係を表している。これより、空隙部６Ｃ反対側の主継鉄部６Ａの断面積を拡大させることで出力エネルギが向上していくが、あるところまで増加するとその増加率は低下し、約１０％増加したところで出力エネルギは増加しなくなることが確認できる。これは主継鉄部６Ａの幅を広げたことでこの箇所の磁束密度が低下していき、磁気飽和しなくなったためである。したがって図１１より空隙部６Ｃ反対側の主継鉄部６Ａ幅の拡大は空隙部６Ｃ側の主継鉄部６Ａに対し、出力エネルギ向上率が低下してくる約２０％〜４０％が必要である。本実施例においては一次巻線３Ａの二層巻回した高さ分が主継鉄部６Ａ拡大幅の約２０％であり、点火コイル１外形を拡大せずに必要主継鉄部６Ａ断面積を確保することが可能である。   Next, the required width of the enlarged portion of the main yoke portion 6A will be described. The enlarged width of the main yoke portion 6A has a relationship as shown in FIG. FIG. 11 shows the result of calculation by magnetic field analysis, and enlargement of the main yoke portion 6A with respect to the main yoke portion 6A on the gap portion 6C side when the width of the main yoke portion 6A on the opposite side of the gap portion is gradually widened. It represents the relationship between width (%) and output energy. As a result, the output energy is improved by enlarging the cross-sectional area of the main yoke portion 6A on the opposite side of the gap 6C. However, when the output energy increases to a certain point, the rate of increase decreases, and the output increases when the output increases by about 10%. It can be confirmed that the energy does not increase. This is because by increasing the width of the main yoke portion 6A, the magnetic flux density at this location is lowered and magnetic saturation is stopped. Therefore, from FIG. 11, the expansion of the width of the main yoke portion 6A on the opposite side of the gap portion 6C requires about 20% to 40% at which the output energy improvement rate decreases with respect to the main yoke portion 6A on the gap portion 6C side. is there. In the present embodiment, the height of the primary winding 3A wound in two layers is about 20% of the enlarged width of the main yoke portion 6A, and the required main yoke portion 6A cross-sectional area without enlarging the ignition coil 1 outer shape. Can be secured.

次に主継鉄部６Ａの拡大部がどの程度必要であるかを説明する。主継鉄部６Ａの拡大位置は図１２に示すような関係がある。図１２は磁場解析により計算した結果であり、空隙部６Ｃ反対側の主継鉄部６Ａの拡大させた幅の位置を空隙部６Ｃ反対側の主継鉄部６Ａの片端から徐々にずらしていった時の主継鉄部６Ａ全長に対する拡大位置（％）と出力エネルギの関係を表している。拡大位置においても拡大幅と同様に拡大部を広げていくことで出力エネルギが向上するが４０％以上では徐々に出力エネルギの向上率は低下し、拡大位置が７０％以上になると拡大部を広げてもさらなる出力エネルギ向上には効果がないことが確認できる。これは上記の主継鉄部６Ａの拡大幅と同様に空隙部６Ｃ近傍まで拡大部を広げても空隙部６Ｃ近傍では磁気飽和していないためである。したがって主継鉄部６Ａの拡大部は主継鉄部全長の４０％〜７０％が必要であり、本実施例では５０％としている。   Next, how much the enlarged portion of the main yoke portion 6A is necessary will be described. The enlarged position of the main yoke portion 6A has a relationship as shown in FIG. FIG. 12 shows the result of calculation by magnetic field analysis. The position of the enlarged width of the main yoke portion 6A on the opposite side of the gap portion 6C is gradually shifted from one end of the main yoke portion 6A on the opposite side of the gap portion 6C. The relationship between the enlarged position (%) and the output energy with respect to the entire length of the main yoke portion 6A is shown. In the enlarged position, the output energy is improved by expanding the enlarged part in the same way as the enlarged width, but the output energy improvement rate gradually decreases at 40% or more, and the enlarged part is expanded when the enlarged position becomes 70% or more. However, it can be confirmed that there is no effect in further improving the output energy. This is because magnetic expansion is not saturated in the vicinity of the gap 6C even if the enlarged portion is expanded to the vicinity of the gap 6C in the same manner as the enlarged width of the main yoke portion 6A. Accordingly, the enlarged portion of the main yoke portion 6A needs 40% to 70% of the entire length of the main yoke portion, and is set to 50% in this embodiment.

本実施例では図１３のように主継鉄部６Ａの拡大部に広がる段付部においては主継鉄部６Ａの長手方向に対し２０°〜８０°のテーパを設け、角部にはＲ０.２ 〜Ｒ２mmのＲ処理を施している。これは段付部からの絶縁用樹脂（具体的には、エポキシ樹脂）１１のクラックを防止させるためである。また、段付部をテーパにすることで一次ボビン２形状も合わせてテーパ形状となり、通常一次巻線３Ａの巻回を行う場合、図１３のように一次巻線３Ａの２層目は１層面のコイルとコイルの間にコイルが配置される。つまり１層目と２層目ではコイルが配列する位置がコイルの半径分ずれている。したがって、一次ボビン２の段付部をテーパにしておけば、２層目は１層目と同数巻回することが可能である。   In the present embodiment, as shown in FIG. 13, the stepped portion extending to the enlarged portion of the main yoke portion 6A is provided with a taper of 20 ° to 80 ° with respect to the longitudinal direction of the main yoke portion 6A, and the corner portion is R0. R processing of 2 to R2 mm is performed. This is to prevent cracking of the insulating resin (specifically, epoxy resin) 11 from the stepped portion. Further, by tapering the stepped portion, the shape of the primary bobbin 2 is also tapered, and when the primary winding 3A is normally wound, the second layer of the primary winding 3A is the first layer surface as shown in FIG. A coil is arranged between the coils. That is, the positions where the coils are arranged in the first and second layers are shifted by the radius of the coils. Therefore, if the stepped portion of the primary bobbin 2 is tapered, the second layer can be wound as many times as the first layer.

さらに点火コイル１の外形を大きくさせずに出力エネルギを向上させたい場合には図
１４のように空隙部側の断面積が小さい主継鉄部６Ａ部を除いた形状をした珪素鋼板を一次ボビン２が収納できる範囲で継鉄部６の上下両側に１〜３枚程度積層させることで継鉄部６の断面積が大きくなり出力エネルギが可能である。 Further, when it is desired to improve the output energy without increasing the outer shape of the ignition coil 1, a silicon steel plate having a shape excluding the main yoke portion 6A having a small sectional area on the gap side as shown in FIG. By stacking about 1 to 3 on the upper and lower sides of the yoke part 6 within a range that can accommodate 2, the cross-sectional area of the yoke part 6 is increased and output energy is possible.

また、継鉄部６の材質を鉄系の粉体により圧着させて図１５のように空隙部６Ｃ反対側の主継鉄部６Ａの断面積を拡大させてもよい。   Alternatively, the material of the yoke portion 6 may be pressure-bonded with iron-based powder to enlarge the cross-sectional area of the main yoke portion 6A on the opposite side of the gap portion 6C as shown in FIG.

次に、図２，図３（ａ），（ｂ），図５（ａ），（ｂ）を用いて、継鉄部６の主継鉄部ａの断面積と側継鉄部ｂ（ｂ１，ｂ２），連結継鉄部ｃ（ｃ１，ｃ２），連結継鉄部ｄ
（ｄ１，ｄ２）の断面積の関係について説明する。図５（ａ），（ｂ）において一次コイル３，二次コイル５を巻回しない側継鉄部ｂ（ｂ１，ｂ２），連結継鉄部ｃ(ｃ１，ｃ２)，連結継鉄部ｄ（ｄ１，ｄ２）の断面積は、一次コイル３，二次コイル５を装着した主継鉄部ａの断面積の約８０％とし、側継鉄部ｂ（ｂ１，ｂ２），連結継鉄部ｃ(ｃ１，ｃ２)，連結継鉄部ｄ（ｄ１，ｄ２）の断面積は、どこの位置でも均一に形成する。 Next, using FIG. 2, FIG. 3 (a), (b), FIG. 5 (a), (b), the cross-sectional area of the main yoke part a of the yoke part 6 and the side yoke part b (b1) , B2), connecting yoke part c (c1, c2), connecting yoke part d
The relationship between the cross-sectional areas (d1, d2) will be described. 5 (a) and 5 (b), the side yoke portion b (b1, b2), the connected yoke portion c (c1, c2), the connected yoke portion d ( The cross-sectional area of d1, d2) is about 80% of the cross-sectional area of the main yoke portion a to which the primary coil 3 and the secondary coil 5 are attached, and the side yoke portion b (b1, b2), the connecting yoke portion c The cross-sectional areas of (c1, c2) and the connecting yoke portion d (d1, d2) are formed uniformly at any position.

ところが、実際の継鉄部６に一次巻線３Ａの通電によって励磁される磁束量は、側継鉄部ｂ（ｂ１，ｂ２），連結継鉄部ｃ（ｃ１，ｃ２），連結継鉄部ｄ（ｄ１，ｄ２）の位置によって異なり、具体的には継鉄部６に設けた空隙部６Ｃの位置によって変化している。この一次巻線３Ａに通電すると、継鉄部６が励磁され、この継鉄部６には、図５（ａ），（ｂ）に示す如く、磁束が流れる。すなわち、空隙部６Ｃの磁気抵抗が継鉄部６の１００倍以上であるため、図５（ａ）に示されるＥ字状に形成される継鉄部６の場合は、空隙部６Ｃで磁束が漏洩し、連結継鉄部ｃ１，ｃ２から主継鉄部ａに短絡したように図５（ａ）に示される如く一部の磁束が流れる。また、磁気抵抗が継鉄部６の１００倍以上であるため、図５（ｂ）に示されるＣ字状に形成される継鉄部６の場合は、空隙部６Ｃで磁束が漏洩し、連結継鉄部ｃから主継鉄部ａに短絡したように図５（ｂ）に示される如く一部の磁束が流れる。   However, the amount of magnetic flux excited in the actual yoke portion 6 by energization of the primary winding 3A includes the side yoke portion b (b1, b2), the connection yoke portion c (c1, c2), and the connection yoke portion d. It differs depending on the position of (d1, d2), and specifically varies depending on the position of the gap 6C provided in the yoke part 6. When the primary winding 3A is energized, the yoke portion 6 is excited, and a magnetic flux flows through the yoke portion 6 as shown in FIGS. 5 (a) and 5 (b). That is, since the magnetic resistance of the gap portion 6C is 100 times or more that of the yoke portion 6, in the case of the yoke portion 6 formed in an E shape shown in FIG. As shown in FIG. 5A, a part of the magnetic flux flows as if leaking and short-circuited from the connecting yoke portions c1 and c2 to the main yoke portion a. Further, since the magnetic resistance is 100 times or more that of the yoke portion 6, in the case of the yoke portion 6 formed in a C shape shown in FIG. As shown in FIG. 5B, a part of the magnetic flux flows as if short-circuited from the yoke portion c to the main yoke portion a.

このように一部の磁束が空隙部６Ｃの近傍で短絡したように流れるため、空隙部６Ｃの付近の側継鉄部ｂ（ｂ１，ｂ２）に流れる磁束量Φ１は、空隙部６Ｃの反対側の連結継鉄部ｄ（ｄ１，ｄ２）に流れる磁束量Φ２よりも少なくなる。したがって、側継鉄部ｂ
（ｂ１，ｂ２），連結継鉄部ｃ（ｃ１，ｃ２），連結継鉄部ｄ（ｄ１，ｄ２）のそれぞれの側継鉄部及び連結継鉄部の必要断面積は、側継鉄部の各形成位置によって異なり、断面積をそれぞれの位置で変えることにより、内燃機関用点火コイルの形状を小さくし、出力エネルギを向上させることができる。 Since a part of the magnetic flux flows like a short circuit in the vicinity of the gap portion 6C in this way, the amount of magnetic flux Φ1 flowing in the side yoke portion b (b1, b2) near the gap portion 6C is opposite to the gap portion 6C. The amount of magnetic flux Φ2 flowing through the connecting yoke portion d (d1, d2) is smaller. Therefore, side yoke part b
(B1, b2), the connecting yoke part c (c1, c2), the connecting yoke part d (d1, d2) of each side yoke part and the required sectional area of the connecting yoke part is the side yoke part Depending on each formation position, the shape of the ignition coil for the internal combustion engine can be reduced and the output energy can be improved by changing the cross-sectional area at each position.

本実施例においては、内燃機関用点火コイルの形状を高出力・小型・軽量化させるために継鉄部６の側継鉄部ｂ（ｂ１，ｂ２），連結継鉄部ｃ（ｃ１，ｃ２），連結継鉄部ｄ
（ｄ１，ｄ２）の断面積をそれぞれの位置によって変化させ、側継鉄部及び連結継鉄部の断面積を必要最小限とした構造に形成している。具体的な比率に関しては下記に示すように磁場解析により計算し求めた。 In the present embodiment, in order to make the shape of the ignition coil for an internal combustion engine high output, small size, and light weight, the side yoke portion b (b1, b2) of the yoke portion 6, the connecting yoke portion c (c1, c2). , Connection yoke part d
The cross-sectional areas of (d1, d2) are changed depending on the respective positions, and the cross-sectional areas of the side yoke portion and the connecting yoke portion are formed to be the minimum necessary. The specific ratio was calculated and determined by magnetic field analysis as shown below.

この図１６に図示の解析結果は、図２のＸ方向において主継鉄部と側継鉄部ｂの最適幅比率を算出するために主継鉄部ａの断面積を１と、図３（ｂ），図５（ｂ）に示されるＣ字形状の場合の側継鉄部ｂ（継鉄部６の形状が図３（ａ），図５（ａ）に示されるＥ字形状の場合にはｂ１＋ｂ２）部分を変化させて解析した結果を示したものである。解析を行う際には図２のＸ方向に対し点火コイル外形の制限を設け、その範囲内で主継鉄部と側継鉄部ｂの幅比率を変化させているので、解析結果より主継鉄部と側継鉄部ｂの最適幅を求めることが可能である。この結果より側継鉄部ｂの断面積は主継鉄部の断面積（平均断面積）に対し、７０％〜１００％とする必要がある。さらに側継鉄部ｂの断面積を拡大させれば若干出力は増加するが、点火コイル外形が余計に拡大し磁気変換効率は劣るため、本実施例は側継鉄部ｂの幅は上記の範囲内とした。   The analysis result shown in FIG. 16 shows that the cross-sectional area of the main yoke portion a is 1 in order to calculate the optimum width ratio of the main yoke portion and the side yoke portion b in the X direction of FIG. b) In the case of the side yoke b in the case of the C shape shown in FIG. 5B (when the shape of the yoke portion 6 is the E shape shown in FIGS. 3A and 5A) Shows the result of analysis by changing the b1 + b2) portion. When the analysis is performed, the outer limit of the ignition coil is set in the X direction in FIG. 2, and the width ratio between the main yoke portion and the side yoke portion b is changed within the range. It is possible to obtain the optimum width of the iron part and the side yoke part b. From this result, the cross-sectional area of the side yoke part b needs to be 70% to 100% with respect to the cross-sectional area (average cross-sectional area) of the main yoke part. Further, if the cross-sectional area of the side yoke part b is enlarged, the output increases slightly, but the outer shape of the ignition coil is enlarged further and the magnetic conversion efficiency is inferior. Therefore, in this embodiment, the width of the side yoke part b is as described above. Within the range.

図１７に図示の解析結果は、図２のＹ方向において連結継鉄部ｃと連結継鉄部ｄの最適幅比率を算出するために図３（ｂ），図５（ｂ）に示されるＣ字形状の場合の連結継鉄部ｃ(継鉄部６の形状が図３（ａ），図５（ａ）に示されるＥ字形状の場合にはｃ１＋ｃ２)と、図３（ｂ），図５（ｂ）に示されるＣ字形状の場合の連結継鉄部ｄ（継鉄部６の形状が図３（ａ），図５（ａ）に示されるＥ字形状の場合にはｄ１＋ｄ２）部分を変化させて解析した結果を示したものである。上記と同様に解析を行う際には図２のＹ方向に対し点火コイル外形の制限を設け、その範囲内で連結継鉄部ｃと連結継鉄部ｄの幅比率を変化させているので、解析結果より連結継鉄部ｃと連結継鉄部ｄの最適幅を求めることが可能である。この結果より連結継鉄部ｃの断面積は連結継鉄部ｄの断面積（平均断面積）に対し、１２０％〜１５０％とする必要がある。さらに連結継鉄部ｃは主継鉄部ａに直結しており、空隙部からも離れていることから、主継鉄部ａの断面積とほぼ同等の断面積を設けたほうがよい。したがって、本実施例においては、連結継鉄部ｃの断面積は主継鉄部の断面積に対し９０％〜１２０％とし、連結継鉄部ｄの断面積は主継鉄部の断面積に対し６０％〜９０％とした。   The analysis results shown in FIG. 17 are based on the results shown in FIGS. 3B and 5B in order to calculate the optimum width ratio between the connecting yoke portion c and the connecting yoke portion d in the Y direction of FIG. Fig. 3 (b), Fig. 3 (b), Fig. 3 (b), Fig. 3 (b), Fig. 3 (b) The connecting yoke part d in the case of the C-shape shown in FIG. 5 (b) (d1 + d2 portion in the case where the yoke part 6 has the E-shape shown in FIGS. 3 (a) and 5 (a)) It shows the result of analysis by changing. When performing analysis in the same manner as described above, the outer limit of the ignition coil is set in the Y direction in FIG. 2, and the width ratio of the connecting yoke portion c and the connecting yoke portion d is changed within that range. It is possible to obtain the optimum width of the connecting yoke part c and the connecting yoke part d from the analysis result. From this result, the cross-sectional area of the connecting yoke part c needs to be 120% to 150% with respect to the cross-sectional area (average cross-sectional area) of the connecting yoke part d. Further, since the connecting yoke portion c is directly connected to the main yoke portion a and is also away from the gap portion, it is better to provide a cross-sectional area substantially equal to the cross-sectional area of the main yoke portion a. Therefore, in this embodiment, the cross-sectional area of the connecting yoke portion c is 90% to 120% with respect to the cross-sectional area of the main yoke portion, and the cross-sectional area of the connecting yoke portion d is equal to the cross-sectional area of the main yoke portion. For 60% to 90%.

図１８に示すように主継鉄部６Ａの高さ方向は全長に亘って同じ厚みに構成し、幅だけを反空隙部側の４０％〜６０％の範囲に亘って残りの部分より幅広に構成することで、本発明の作用効果の一部を得ることができる。   As shown in FIG. 18, the height direction of the main yoke portion 6 </ b> A is configured to have the same thickness over the entire length, and only the width is wider than the remaining portion over the range of 40% to 60% on the side opposite to the gap. By configuring, part of the operational effects of the present invention can be obtained.

本実施例の特徴は以下の通りである。内燃機関の各シリンダのプラグホールに装着されて点火プラグに直結し使用される独立点火形の内燃機関用点火コイルであって、側継鉄部と主継鉄部とによって閉磁気回路を構成し、主継鉄部は一端が連結継鉄部に固着され、他端が連結継鉄部と空隙部を設けて配置されて閉磁路が形成され、主継鉄部が収納された一次ボビンの上に一次コイルを巻装して収納し、一次ボビンと空隙をもって配置される二次ボビンの上に二次コイルを巻装して収納され、一次ボビンと二次ボビンを間隔をもって配置してコイルケース内に収容し、コイルケース内に絶縁用樹脂を封入して一体化してなる内燃機関用点火コイルにおいて，主継鉄部をストレート形状ではなく、一次コイルを２層巻回した高さ分だけ空隙部反対側の主継鉄部を幅方向に拡大させ段付形状とし、さらに側継鉄部及び連結継鉄部の形状を主継鉄部と側継鉄部及び連結継鉄部とに流れる磁束の量に比例する側継鉄部及び連結継鉄部の断面積を側継鉄部及び連結継鉄部のそれぞれの位置で変化させ、磁束の量に比例した断面積に形成したものである。   The features of this embodiment are as follows. An ignition coil for an internal combustion engine of an independent ignition type that is attached to a plug hole of each cylinder of the internal combustion engine and directly connected to the spark plug, and a closed magnetic circuit is constituted by a side yoke portion and a main yoke portion. The main yoke part has one end fixed to the connecting yoke part and the other end provided with a connecting yoke part and a gap to form a closed magnetic circuit, and the upper part of the primary bobbin containing the main yoke part. The primary coil is wound and stored, and the secondary bobbin is wound and stored on the secondary bobbin that is arranged with the primary bobbin and the gap, and the primary bobbin and the secondary bobbin are arranged with an interval between them to form a coil case. In an internal combustion engine ignition coil that is housed in a coil case and integrated by encapsulating an insulating resin, the main yoke is not straight, but the gap is the height of the primary coil wound in two layers. Stepped by expanding the main yoke on the opposite side in the width direction In addition, the shape of the side yoke portion and the connecting yoke portion is broken in proportion to the amount of magnetic flux flowing through the main yoke portion, the side yoke portion, and the connecting yoke portion. An area is changed in each position of a side yoke part and a connection yoke part, and it forms in the cross-sectional area proportional to the quantity of magnetic flux.

本発明は、継鉄部の形状が中心に主継鉄部を備えその両側に側継鉄部が一本乃至二本並行に設けられた閉磁路型の継鉄部を備えたものに利用できる。   INDUSTRIAL APPLICABILITY The present invention can be used for a case in which the shape of the yoke portion is provided with a main yoke portion at the center and a closed magnetic circuit type yoke portion in which one or two side yoke portions are provided in parallel on both sides thereof. .

また、内燃機関だけでなく、一般的なトランスにも適用できる。   Moreover, it is applicable not only to an internal combustion engine but also to a general transformer.

本発明に係る内燃機関点火コイルの一実施例を示す断面図。1 is a cross-sectional view showing one embodiment of an internal combustion engine ignition coil according to the present invention. 図１に図示の内燃機関点火コイルのＸ−Ｘ線の断面図。Sectional drawing of the XX line of the internal combustion engine ignition coil shown in FIG. 図１に図示の内燃機関用点火コイルの主継鉄部と側継鉄部の形状を示す図。The figure which shows the shape of the main yoke part and side yoke part of the ignition coil for internal combustion engines shown in FIG. 一般的な内燃機関用点火コイルを示す断面図。Sectional drawing which shows the general ignition coil for internal combustion engines. 図１に図示の一次コイルに通電して励磁される継鉄部における磁束の流れを示す図。The figure which shows the flow of the magnetic flux in the yoke part energized and energized to the primary coil shown in FIG. 一般的な内燃機関用点火コイルの磁束密度分布を示す図。The figure which shows magnetic flux density distribution of the ignition coil for general internal combustion engines. （ａ）一般的な内燃機関用点火コイルの一次コイルの巻回した形状を示す図、（ｂ）本実施例の一次コイルの巻回した形状を示す図。(A) The figure which shows the shape which the primary coil of the general internal combustion engine ignition coil was wound, (b) The figure which shows the shape which the primary coil of the present Example wound. 本実施例形状の磁束密度分布を示す図。The figure which shows magnetic flux density distribution of a present Example shape. 出力エネルギを計算する説明図。Explanatory drawing which calculates output energy. 一般的な珪素鋼板の磁気特性を示す図。The figure which shows the magnetic characteristic of a general silicon steel plate. 主継鉄部の拡大幅率と出力エネルギの関係を示す図。The figure which shows the relationship between the expansion width ratio of a main yoke part, and output energy. 主継鉄部の拡大位置と出力エネルギの関係を示す図。The figure which shows the relationship between the expansion position of a main yoke part, and output energy. 図３のＡ部における拡大図を示す図。The figure which shows the enlarged view in the A section of FIG. 本実施例においてさらに出力を向上させるための手法を示す図（１）。FIG. 2A is a diagram (1) showing a method for further improving output in the present embodiment. 本実施例においてさらに出力を向上させるための手法を示す図（２）。FIG. 2 is a diagram (2) showing a method for further improving the output in the present embodiment. 側継鉄部ｂ（ｂ１＋ｂ２）と主継鉄部ａの幅比に対する出力エネルギの関係を示す図。The figure which shows the relationship of the output energy with respect to the width ratio of the side yoke part b (b1 + b2) and the main yoke part a. 連結継鉄部ｃ（ｃ１＋ｃ２）と連結継鉄部ｄ（ｄ１＋ｄ２）の幅比に対する出力エネルギの関係を示す図。The figure which shows the relationship of the output energy with respect to the width ratio of the connection yoke part c (c1 + c2) and the connection yoke part d (d1 + d2). 他の実施例になる継鉄部を示す図面。Drawing which shows the yoke part which becomes another Example.

符号の説明Explanation of symbols

１ 内燃機関用点火コイル
２ 一次ボビン
３ 一次コイル
３Ａ 一次巻線
４ 二次ボビン
５ 二次コイル
５Ａ 二次巻線
６ 継鉄部
６Ａ 主継鉄部
６Ｂ１，６Ｂ２ 連結継鉄部
６Ｃ 空隙部
６Ｄ１，６Ｄ２ 側継鉄部
７ コイルケース
８ 端子
８Ａ 一次巻線端
９ 高圧端子
９Ａ 二次巻線端
１０ 絶縁用樹脂 DESCRIPTION OF SYMBOLS 1 Ignition coil 2 for internal combustion engines Primary bobbin 3 Primary coil 3A Primary winding 4 Secondary bobbin 5 Secondary coil 5A Secondary winding 6 Relay part 6A Main yoke part 6B1, 6B2 Connection yoke part 6C Gap part 6D1, 6D2 Side yoke 7 Coil case 8 Terminal 8A Primary winding end 9 High voltage terminal 9A Secondary winding end 10 Insulating resin

Claims (11)

外周を一次コイル，二次コイルの順でコイルが取巻く主継鉄部と、
この主継鉄部に並行に配置された側継鉄部と、
両継鉄部の端部を連結する一対の連結継鉄部とを備え、
前記主継鉄部の一端と前記連結継鉄部の一方との間に空隙部が設けられており、
前記主継鉄部分は前記空隙部に近い部分に反空隙側よりも細くて断面積が小さい部分が形成されており、
前記一次コイルが前記空隙側で、反空隙側に比べて巻線の段数が多く形成されている
内燃機関用点火コイル。 The primary yoke part that surrounds the outer periphery in the order of the primary coil and the secondary coil,
A side yoke part arranged in parallel to this main yoke part,
A pair of connecting yokes connecting the ends of both yokes,
A gap is provided between one end of the main yoke portion and one of the connecting yoke portions,
The main yoke portion is formed in a portion close to the gap portion, which is thinner than the side opposite the gap and has a small cross-sectional area ,
An ignition coil for an internal combustion engine , wherein the primary coil is formed on the gap side and has a larger number of windings than the non-gap side . 請求項１に記載したものにおいて、
前記一次コイルは前記主継鉄部分の前記細くて断面積の小さい部分の外周において、前記主継鉄部分の前記反空隙側の太くて断面積の大きい部分に比べて前記一次コイルの最小巻き径が小さく形成されており、且つ前記巻数が前記反空隙部側より前記空隙部側の方が多くなるよう構成されている
内燃機関用点火コイル。 In claim 1,
The primary coil has a minimum winding diameter of the primary coil at the outer periphery of the thin and small cross-sectional area of the main yoke portion compared to a thick and large cross-sectional area of the main yoke portion on the anti-air gap side. The ignition coil for an internal combustion engine is configured so that the number of turns is larger on the gap side than on the side opposite the gap. 請求項１若しくは２のいずれかに記載したものにおいて、
前記主継鉄部は前記空隙部側の幅より前記反空隙部側の幅を広くして前記主継鉄の断面積が前記空隙部側に対し、１.１〜１.５倍に構成されている
内燃機関用点火コイル。 In one of claims 1 and 2,
The main yoke portion has a width on the side opposite to the air gap portion larger than a width on the air gap portion side, and a cross-sectional area of the main iron is 1.1 to 1.5 times that of the air gap portion side. An ignition coil for an internal combustion engine. 請求項１乃至３のいずれかに記載したものにおいて、前記主継鉄部の前記反空隙部側の幅は、前記空隙部側の幅より片側の幅が前記一次コイルの巻線の線径の２倍分だけ大きい内燃機関用点火コイル。   4. The width according to claim 1, wherein a width of the main yoke portion on the side opposite to the air gap is smaller than a width on the air gap side of the wire diameter of the winding of the primary coil. An internal combustion engine ignition coil that is twice as large. 請求項１乃至４のいずれかに記載したものにおいて、前記主継鉄部の前記断面積の大きい部分の長手方向長さは前記空隙部側の前記主継鉄部端部から前記主継鉄部の長さの約４０〜６０％の範囲までとした
内燃機関用点火コイル。 The length in the longitudinal direction of the large cross-sectional area of the main yoke portion from the end portion of the main yoke portion on the gap side is the main yoke portion. An ignition coil for an internal combustion engine up to a range of about 40 to 60% of the length. 請求項４に記載したものにおいて、前記主継鉄部の断面積小部分と断面大部分の繋がり部に形成された断面拡大部が、前記主継鉄部長手方向に対し２０〜８０°のテーパ面で構成されている内燃機関用点火コイル。   The cross-sectional enlarged portion formed in the connecting portion of the cross-sectional area small portion and the large cross-sectional portion of the main yoke portion is 20 to 80 ° taper with respect to the longitudinal direction of the main yoke portion. An ignition coil for an internal combustion engine comprising a surface. 請求項６に記載したものにおいて、前記主継鉄部の断面積拡大部のエッジ部には半径０.２〜２mmの面取りが施されている内燃機関用点火コイル。 7. The ignition coil for an internal combustion engine according to claim 6, wherein a chamfer having a radius of 0.2 to 2 mm is provided at an edge portion of the cross-sectional area enlarged portion of the main yoke portion. 請求項１に記載したものにおいて、前記一次ボビンの内側断面が主継鉄部の断面積の変化に対応して空隙部側で小さく、反対側で大きく形成され、その結果一次コイルの巻数が空隙部側で多く、反対側で少なくなっている内燃機関用点火コイル。   The inner cross-section of the primary bobbin is formed to be small on the gap portion side and large on the opposite side in accordance with the change in the cross-sectional area of the main yoke portion, and as a result, the number of turns of the primary coil is a gap. An ignition coil for an internal combustion engine that is large on the part side and small on the opposite side. 請求項１に記載した内燃機関用点火コイルの製造方法において、前記一次コイルの巻線方法は、前記一次ボビン空隙部側の断面積が小さい部分に始め２段巻き、３段目からは前記一次ボビンの巻線部全体を利用して前記一次巻線を巻回するものである内燃機関用点火コイルの製造方法。 2. The method for manufacturing an ignition coil for an internal combustion engine according to claim 1 , wherein the winding method of the primary coil is such that the primary bobbin gap side has a small cross-sectional area and starts from the second stage, and from the third stage, the primary A method of manufacturing an ignition coil for an internal combustion engine , wherein the primary winding is wound using the entire winding portion of a bobbin. 請求項１に記載した内燃機関用点火コイルの製造方法において、前記主継鉄部の前記空隙側に位置する連結継鉄部が別体に形成されており、前記一次ボビンの内側断面積が大きい側から前記主継鉄部に挿入して、コイルを組付け、しかる後に前記連結継鉄部を主継鉄部及び側継鉄部に固定する内燃機関用点火コイルの製造方法。 2. The method of manufacturing an ignition coil for an internal combustion engine according to claim 1 , wherein a connecting yoke portion located on the gap side of the main yoke portion is formed separately, and an inner cross-sectional area of the primary bobbin is large. A method of manufacturing an ignition coil for an internal combustion engine, wherein the coil is assembled by inserting the coil into the main yoke portion from the side, and then fixing the connecting yoke portion to the main yoke portion and the side yoke portion. 請求項１に記載したものにおいて、
前記継鉄部の側継鉄部ｂ（ｂ１＋ｂ２）部の断面積は前記主継鉄部断面積（平均断面積）に対し０.７〜１.０倍、連結継鉄部ｃ（ｃ１＋ｃ２）部の断面積は前記主継鉄部断面積（平均断面積）に対し０.９〜１.２倍、連結継鉄部ｄ（ｄ１＋ｄ２）部の断面積は前記主継鉄部断面積（平均断面積）に対し０.６〜０.９とし、一次電流を通電した際に継鉄部に発生する磁束密度の値が継鉄部材料の飽和磁束密度を超えないように継鉄部の断面積を設定した内燃機関用点火コイル。 In claim 1,
The cross-sectional area of the side yoke part b (b1 + b2) of the yoke part is 0.7 to 1.0 times the cross-sectional area (average cross-sectional area) of the main yoke part, and the connected yoke part c (c1 + c2) part. The cross-sectional area of the main yoke part is 0.9 to 1.2 times the cross-sectional area (average cross-sectional area), and the cross-sectional area of the connecting yoke part d (d1 + d2) is the cross-sectional area of the main yoke part (average section) The cross-sectional area of the yoke part so that the value of the magnetic flux density generated in the yoke part when the primary current is applied does not exceed the saturation magnetic flux density of the yoke part material. An internal combustion engine ignition coil.
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