【０００１】
【発明の属する技術分野】
この発明は、シリンダブロックの外に固定された点火コイルの、プラグホールの中に浅く突入した下向きの高圧筒の下端の高圧端子に誘起された高電圧を、シリンダブロックのプラグホールの底に貫通して固定された点火プラグの頂部電極に供給するための内燃機関のプラグソケットに関する。
【０００２】
【従来の技術】
上記のように、点火コイルの高圧端子に誘起された高電圧をプラグホールの底に固定された点火プラグの頂部電極にプラグソケットで供給することは本特許出願人の特開２０００−２９４４３４号公報によって公知である。
【０００３】
【発明が解決しようとする課題】
上記公開公報に記載されたプラグソケットは、点火プラグの碍子部に上から被さるプラグ嵌合部と、点火コイルの高圧筒に下から被さる高圧筒嵌合部を夫々ゴムで別々に成形し、これらを合成樹脂のパイプなどの両端部に連結するため製造、組立てに非常に手数がかかる。このため、図３に示すようにプラグソケットをゴムで一連に成形したものも公知であるが、プラグソケットを成形する際、そのプラグ嵌合部１１と高圧筒嵌合部１２とを連結する連結部の中心に、上下の両端に大径部２２、２４を有する金属の導電棒材２１を貫通して保持させねばならないので成形が面倒である。又、上端の大径部２２には点火コイルの高圧端子に下から弾力的に接触するコイルバネ２３、下端の大径部２４には点火プラグの頂部電極に上から弾力的に接触するコイルバネ２５を、夫々ビス２６などを使って固定する必要があり、部品点数が多いと共に、組立てに手数がかかる。更に、ノイズ低減用の抵抗を連結部中に設けようとしても導電棒材が貫通しているので不可能である。
【０００４】
【課題を解決するための手段】
本発明は、上述した問題点を解消するために開発されたもので、シリンダブロックのプラグホールの底に貫通して取り付けられた点火プラグの頂部電極を有する碍子部に上から被さる筒形のゴム製プラグ嵌合部、上記プラグホールの上に位置してシリンダブロックに固定された点火コイルの、下端に高圧端子を有し、上記プラグホール中に上から浅く突入する下向きの高圧筒に下から被さる筒形のゴム製高圧筒嵌合部とを備え、点火コイルの高圧端子に誘起された高電圧を点火プラグに供給する内燃機関のプラグソケットにおいて、上記プラグ嵌合部と高圧筒嵌合部とをゴムの連結筒部で一体に連結し、上記連結筒部の内周に、段差によって大径部と小径部を上下に設け、この連結筒部の内周に、上記大径部と小径部に嵌合する大径部と小径部とを上下に備え、且つ上記高圧端子に下から接触する上部コイルバネ及び上記点火プラグの頂部電極に上から接触する下部コイルバネを内臓した段差付き合成樹脂パイプを圧入し、上記合成樹脂パイプの段差を連結筒部の内周の段差に当接して上記連結筒部の内周に段差付き合成樹脂パイプを固定したことを特徴とする。
【０００５】
【発明の実施の形態】
図１は本発明の第１実施例、図２は同じく第２実施例を示し、これらはプラグ嵌合部１１、高圧筒嵌合部１２、連結筒部１３からなる中空の中継絶縁筒体１０をゴムで一体に成形してある。
【０００６】
上端が高圧筒嵌合部１２，下端がプラグ嵌合部１１に連通した連結筒部の内周の途中に段差１４を設け、段差から上は大径部１３ａ、下は小径１３ｂとする。例えば、大径部１３ａの内径は１０ｍｍ、小径部１３ｂの内径は８ｍｍである。
【０００７】
連結筒部１３の内周に対応して、途中の段差１６から上が太くて上記連結筒部の大径部１３ａの内周に圧入でき、段差１６から下が細くて上記連結筒部の小径部１３ｂの内周に圧入できる段差付き合成樹脂パイプ１５を成形し、この段差付き合成樹脂パイプ１５を小径部１５ｂから中継絶縁筒体１０の高圧筒嵌合部を通じ連結筒部１３の内周に圧入する。
【０００８】
段差付き合成樹脂パイプ１５の段差１６が連結筒部１３中の段差１４に当接すると、それ以上の圧入は不可能になり、段差付き合成樹脂パイプの段差１６から上の大径部１５ａは連結筒部１３の大径部１３ａの内周に嵌合し、段差から下の小径部１５ｂは連結筒部の小径部１３ｂの内周に嵌合し、こうして段差付き合成樹脂パイプ１５は中継絶縁筒体の連結筒部１３中に固定される。
【０００９】
図１の実施例では１本のコイルバネ１７を連結筒部１３の内周に貫通し、このコイルバネ１７により点火コイルの高圧端子に誘起された高電圧を点火プラグの頂部電極に供給する。このためコイルバネ１７には連結筒部１３の大径部１３ａ内周に嵌合し、下端が段差１６に当接する密な巻回部１７ａを中央部に設けて上記大径部１３中に位置させ、この密な巻回部１７ａの上下にバネを引き伸ばして直径を減少させた小径部１７ｂ、１７ｃを設け、上の小径部１７ｂを高圧筒嵌合部１２中に突入させて高圧端子に下から弾力的に接触できるようにし、下の小径部１７ｃはプラグ嵌合部１１中に突入させて点火プラグの頂部電極に上から弾力的に接触できるようにしてある。
【００１０】
上記コイルバネ１７は中央部の密な巻回部１７ａの外周が連結筒部の大径部１３ａの内周に摩擦接触していること、その密な巻回部１７ａの下端が合成樹脂パイプ１５の段差１６に上から当接していることにより上記パイプ１５中に保持される。
【００１１】
図２の実施例では、上端部の密な巻回部１８ａを段差付き合成樹脂パイプ１５の大径部１５ａに保持されたコイルバネ１８を下向きに引き伸ばして小径部１８ｂとし、この小径部がプラグ嵌合筒１１中に突入して点火プラグの頂部電極に接触するようになっている。このコイルバネ１８は、上の密な巻回部１８ａの外周が連結筒部の大径部１３ａの内周に摩擦接触していること、その密な巻回部１８ａの下端が合成樹脂パイプ１５の段差１６に上から当接していることにより上記パイプ１５中に保持される。
【００１２】
合成樹脂パイプ１５の大径部１５中には、コイルバネ１８の密な巻回部１８ａの上に位置してノイズ低減用の抵抗１９が接触し、その上に、上端部が高圧筒嵌合部１２中に下から突入して高圧端子と接触する第２のコイルバネ２０が設けてある。この抵抗１９とコイルバネ２０とは導電性のあるキャップを介して固定される。つまりキャップ内に抵抗を固定し、キャップ外にコイルバネを固定する。
【００１３】
【発明の効果】
以上で明らかなように、本発明ではゴム製のプラグ嵌合部と高圧筒嵌合部とを一体に連結する連結筒部の内周に段差を設け、上記段差に当接する段差を備えた段差付き合成樹脂パイプを上記連結筒部中に圧入して固定し、段差付き合成樹脂パイプ中に内臓されたコイルバネを介し点火コイルの高圧端子に誘起された高電圧を点火プラグの頂部電極に供給する。段差付き合成樹脂パイプを使用する分、連結筒部を構成するゴムの肉厚を薄くできると共に、連結筒部の変形時の応力が段差付き合成樹脂パイプ内にかからないため上記パイプ内にノイズ低減用の抵抗を設けることが可能になる。更に、構成部品の点数を削減でき、組付ける作業性の向上や、材料コストの削減も達成できる。
【図面の簡単な説明】
【図１】本発明によるプラグソケットの第１実施例の断面図。
【図２】本発明によるプラグソケットの第２実施例の断面図。
【図３】従来のプラグソケットの断面図。
【符号の説明】
１１ プラグ嵌合部
１２ 高圧筒嵌合部
１３ 連結筒部
１３ａ 連結筒部の大径部
１３ｂ 連結筒部の小径部
１４ 連結筒部の段差
１５ 段差付き合成樹脂パイプ
１５ａ 段差付き合成樹脂パイプの大径部
１５ｂ 段差付き合成樹脂パイプの小径部
１６ 段差付き合成樹脂パイプの段差
１７、１８、２０ コイルバネ
１９ ノイズ低減用抵抗[0001]
TECHNICAL FIELD OF THE INVENTION
According to the present invention, a high voltage induced in a high-voltage terminal at a lower end of a downward high-pressure cylinder, which protrudes shallowly into a plug hole, of an ignition coil fixed outside a cylinder block, passes through a bottom of a plug hole of the cylinder block. The invention relates to a plug socket of an internal combustion engine for supplying a fixed top electrode of a spark plug.
[0002]
[Prior art]
As described above, supplying a high voltage induced at a high voltage terminal of an ignition coil to a top electrode of an ignition plug fixed to the bottom of a plug hole by a plug socket is disclosed in Japanese Patent Application Laid-Open No. 2000-294434 of the present applicant. Is known.
[0003]
[Problems to be solved by the invention]
In the plug socket described in the above-mentioned publication, a plug fitting portion that covers the insulator portion of the ignition plug from above and a high-pressure cylinder fitting portion that covers the high-pressure cylinder of the ignition coil from below are separately molded of rubber, respectively. Since it is connected to both ends of a synthetic resin pipe or the like, production and assembly are extremely troublesome. For this reason, as shown in FIG. 3, a plug socket formed of a series of rubber is also known. However, when the plug socket is formed, a connection for connecting the plug fitting portion 11 and the high-pressure cylinder fitting portion 12 is formed. In the center of the portion, the metal conductive rod 21 having large-diameter portions 22 and 24 at both upper and lower ends must be penetrated and held, so that molding is troublesome. A coil spring 23 elastically contacts the high voltage terminal of the ignition coil from below on the large diameter portion 22 at the upper end, and a coil spring 25 elastically contacts the top electrode of the ignition plug from above on the large diameter portion 24 on the lower end. Need to be fixed using screws 26 or the like, and the number of parts is large, and the assembling is troublesome. Further, it is not possible to provide a noise reducing resistor in the connecting portion because the conductive bar material penetrates.
[0004]
[Means for Solving the Problems]
SUMMARY OF THE INVENTION The present invention has been developed to solve the above-described problem, and has a cylindrical rubber covering from above a insulator having a top electrode of a spark plug attached to a bottom of a plug hole of a cylinder block. A plug fitting portion, an ignition coil positioned above the plug hole and fixed to the cylinder block, has a high-voltage terminal at the lower end, and is provided with a downward-facing high-pressure cylinder that projects shallowly from above into the plug hole from below. A plug-type rubber high-pressure cylinder fitting portion for covering, the plug socket of the internal combustion engine supplying a high voltage induced at the high-voltage terminal of the ignition coil to the ignition plug; Are connected integrally by a rubber connecting tube portion, and a large-diameter portion and a small-diameter portion are vertically provided on the inner periphery of the connecting tube portion by a step, and the large-diameter portion and the small-diameter portion are provided on the inner periphery of the connecting tube portion. Large diameter part and small diameter to fit in the part And press-fit a stepped synthetic resin pipe with a built-in upper coil spring that contacts the high voltage terminal from below and a lower coil spring that contacts the top electrode of the ignition plug from above. A stepped synthetic resin pipe is fixed to the inner periphery of the connecting tubular portion in contact with a step on the inner periphery of the connecting tubular portion.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a first embodiment of the present invention, and FIG. 2 shows a second embodiment of the present invention. These are hollow relay insulating cylinders 10 comprising a plug fitting part 11, a high-pressure cylinder fitting part 12, and a connecting cylinder part 13. Is molded integrally with rubber.
[0006]
A step 14 is provided in the middle of the inner circumference of the connecting cylinder part whose upper end communicates with the high-pressure cylinder fitting part 12 and whose lower end communicates with the plug fitting part 11. The large diameter part 13 a is above the step and the small diameter 13 b is below. For example, the inner diameter of the large diameter portion 13a is 10 mm, and the inner diameter of the small diameter portion 13b is 8 mm.
[0007]
Corresponding to the inner circumference of the connecting cylinder portion 13, the upper portion is thicker from the middle step 16 and can be pressed into the inner circumference of the large-diameter portion 13a of the connecting cylinder portion. A stepped synthetic resin pipe 15 that can be pressed into the inner periphery of the portion 13b is formed, and the stepped synthetic resin pipe 15 is inserted from the small-diameter portion 15b to the inner periphery of the connecting tube portion 13 through the high-pressure tube fitting portion of the relay insulating tube 10. Press in.
[0008]
When the step 16 of the stepped synthetic resin pipe 15 comes into contact with the step 14 in the connecting cylindrical portion 13, further press-fitting becomes impossible, and the large-diameter portion 15 a above the step 16 of the stepped synthetic resin pipe is connected. The small-diameter portion 15b below the step fits into the inner circumference of the small-diameter portion 13b of the connecting cylindrical portion, and thus the stepped synthetic resin pipe 15 is fitted to the intermediate insulating tube. It is fixed in the connecting cylinder 13 of the body.
[0009]
In the embodiment shown in FIG. 1, one coil spring 17 penetrates the inner periphery of the connecting tube portion 13, and the high voltage induced at the high voltage terminal of the ignition coil by this coil spring 17 is supplied to the top electrode of the ignition plug. For this reason, the coiled spring 17 is fitted on the inner periphery of the large diameter portion 13a of the connecting cylinder portion 13, and a dense winding portion 17a whose lower end is in contact with the step 16 is provided at the center portion so as to be positioned in the large diameter portion 13. The small-diameter portions 17b and 17c whose diameters have been reduced by extending the springs above and below the densely wound portion 17a are provided, and the upper small-diameter portion 17b is inserted into the high-pressure cylinder fitting portion 12 so that the high-voltage terminal is inserted from below. The lower small-diameter portion 17c protrudes into the plug fitting portion 11 so that it can elastically contact the top electrode of the ignition plug from above.
[0010]
The coil spring 17 is such that the outer periphery of the densely wound portion 17a at the center is in frictional contact with the inner periphery of the large-diameter portion 13a of the connecting tubular portion, and the lower end of the densely wound portion 17a is By being in contact with the step 16 from above, it is held in the pipe 15.
[0011]
In the embodiment shown in FIG. 2, the densely wound portion 18a at the upper end is extended downward to the coil spring 18 held by the large-diameter portion 15a of the stepped synthetic resin pipe 15 to become a small-diameter portion 18b, and this small-diameter portion is plug-fitted. It projects into the joint tube 11 and contacts the top electrode of the spark plug. The coil spring 18 is configured such that the outer periphery of the upper densely wound portion 18a is in frictional contact with the inner periphery of the large-diameter portion 13a of the connecting cylindrical portion, and the lower end of the densely wound portion 18a is By being in contact with the step 16 from above, it is held in the pipe 15.
[0012]
In the large diameter portion 15 of the synthetic resin pipe 15, a noise reducing resistor 19 is located above the densely wound portion 18 a of the coil spring 18, and the upper end thereof has a high-pressure cylinder fitting portion. There is provided a second coil spring 20 which protrudes from below into and contacts the high voltage terminal. The resistor 19 and the coil spring 20 are fixed via a conductive cap. That is, the resistance is fixed inside the cap, and the coil spring is fixed outside the cap.
[0013]
【The invention's effect】
As is apparent from the above, according to the present invention, a step is provided on the inner periphery of the connecting cylinder part that integrally connects the rubber plug fitting part and the high-pressure cylinder fitting part, and the step having the step abutting on the step is provided. The synthetic resin pipe with a pressure is fixed by press-fitting into the connecting cylinder part, and the high voltage induced at the high voltage terminal of the ignition coil is supplied to the top electrode of the ignition plug via a coil spring built in the synthetic resin pipe with a step. . The use of the stepped synthetic resin pipe reduces the thickness of the rubber that composes the connecting cylinder part, and reduces noise in the above pipe because the stress at the time of deformation of the connecting cylinder part is not applied to the stepped synthetic resin pipe. Can be provided. Further, the number of component parts can be reduced, the workability of assembling can be improved, and the material cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a sectional view of a first embodiment of a plug socket according to the present invention.
FIG. 2 is a sectional view of a second embodiment of the plug socket according to the present invention;
FIG. 3 is a sectional view of a conventional plug socket.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Plug fitting part 12 High-pressure cylinder fitting part 13 Connection cylinder part 13a Large diameter part 13b of connection cylinder part Small diameter part of connection cylinder part 14 Step of connection cylinder part 15 Stepped synthetic resin pipe 15a Large synthetic resin pipe with step Diameter portion 15b Small diameter portion 16 of synthetic resin pipe with step Steps 17, 18, 20 of synthetic resin pipe with step Coil spring 19 Resistance for noise reduction
