JP5173585B2 - Ignition coil for internal combustion engine - Google Patents

Description

  The present invention relates to a structure of a plug boot portion of an ignition coil for an internal combustion engine.

  FIG. 5 shows a diagram of an ignition coil for an internal combustion engine according to the prior art, and FIG. 6 shows an enlarged sectional view of the plug boot portion of FIG. Conventionally, in an ignition coil for an internal combustion engine, a primary coil 120, a secondary coil 130, and a core 170 are housed in a case 110, and a primary connector 160 that supplies primary power from a battery is provided in the case 110. There has been proposed an ignition coil 100 in which a part of the case 110 is accommodated in the plug hole of the engine and a high voltage of several tens of KV generated from the secondary coil 130 is directly supplied to an ignition plug (not shown).

  The ignition coil 100 accommodates a rod-shaped central core 170, a primary coil 120 coaxially with the central core 170, and a secondary coil 130 in a case 110 having an upper opening, and is filled with epoxy resin or the like from the opening. Insulation casting is performed by pouring resin. The lower portion of the case 110 projects a high-voltage tower 111 having a lower opening into which a plug boot 150 made of rubber elastic material is fitted. The high-voltage tower 111 is electrically connected to the secondary coil 130. A high voltage terminal 140 having an open cup shape, and the high voltage terminal 140 is electrically connected to the spark plug via a spirally formed conductive spring 145 disposed inside the plug boot 150 to be connected. Is done. The high-voltage terminal 140 is formed with an inner peripheral groove 141 at the inner bottom, and the inner peripheral groove 141 and the annular portion 145a at one end on the ignition coil side of the spring 145 are fitted to each other, so that the electrical and mechanical Connected. Further, the plug boot portion 150 is fitted with a protruding wall 153 protruding toward the inner peripheral side of the opening of the high-pressure tower portion 111 in contact with the inner peripheral side of the opening of the high-pressure tower portion 111.

An ignition coil that accommodates a part of such a case in a plug hole is disclosed in, for example, Japanese Patent Application Laid-Open No. 2003-017341 (Patent Document 1). Power is distributed to the spark plug via a spring inside the unit.
JP 2003-017341 A

  However, in the above-described conventional configuration, there is a case where the projecting wall protruding toward the inner peripheral side of the high-pressure tower portion of the plug boot portion is caught by the spark plug-side tip portion of the spring during assembly, and the spring is dropped from the high-pressure terminal. Further, if the spring 145 is fitted into the inner peripheral groove 141 of the high-voltage terminal 140 and is not electrically and mechanically connected, assembly failure occurs. Therefore, accurate and reliable fitting has to be performed.

In order to solve the above problems, the present invention has the following configuration. In other words, the present invention includes a core, a primary coil and a secondary coil arranged coaxially with the core, and the primary coil and the secondary coil are electromagnetically coupled via the core. A primary connector that supplies power and an ignition signal to the secondary coil, a case that accommodates the primary coil and the secondary coil, a high-voltage tower portion that is formed to protrude from the lower portion of the case, and an internal portion of the high-voltage tower portion A high voltage terminal that is electrically connected to the secondary coil, a conductive member that electrically connects the high voltage terminal and the spark plug, and a plug boot portion made of an elastic material that connects the high voltage tower and the spark plug; In the ignition coil for an internal combustion engine, the plug boot portion includes a receiving portion having both ends open and a small diameter portion in which the opening diameter of both ends for receiving the conductive member is smaller than the inside of the plug boot portion. Preparation The high-voltage terminal includes a conductive member fitting portion that is a cylindrical conductive material and fits with the conductive member, and the conductive member fitting portion has a tapered portion that has a diameter that decreases in a direction outside the cylindrical axis, and the tapered portion. A groove portion into which the annular portion fits is formed on the outer periphery of the base high-voltage terminal, and the groove portion has a bottom that is smaller than the outer peripheral diameter of the cylinder and at least equal to or larger than the inner diameter of the annular portion. A spring made of a conductive wire in a spiral shape, both ends are small in diameter, the middle is larger in diameter than both ends, and has a high-voltage terminal fitting portion that fits the high-voltage terminal. The portion is formed by an annular portion in which a conductive wire is formed in an annular shape.

According to the configuration of the invention according to claim 1, with a simple configuration, the projecting wall that easily accommodates the conductive member in the accommodating portion of the plug boot portion and protrudes toward the inner peripheral side of the high pressure tower portion of the plug boot portion, It is not caught by the tip of the spring during assembly and the spring is not dropped from the high-voltage terminal. Further, since the high-voltage terminal has a fitting portion in which the conductive member is fitted to each other, the high-voltage terminal can be fitted with one touch.

  FIG. 1 shows a diagram of an ignition coil for an internal combustion engine representing the first embodiment to which the technology of the present invention is applied. FIG. 2 shows an enlarged sectional view of the plug boot portion of FIG. FIG. 3 shows an assembly diagram for accommodating a spring in a plug boot portion representing 1. FIG. 4 shows an assembly diagram of a plug boot portion accommodating a spring and a high-voltage terminal representing Example 1 to which the technology of the present invention is applied. . 1 to 2, an ignition coil 1 according to an embodiment of the present invention includes a rod-shaped center core 70, a primary coil 20 wound around a primary conductor disposed coaxially with the center core 70, and 2 A secondary coil 30 wound with a secondary conducting wire, and the primary coil 20 and the secondary coil 30 are electromagnetically coupled via the central core 70 and formed of an insulating material. The primary coil 20 and the secondary coil 30 includes a primary connector 60 that supplies power and an ignition signal to the primary coil 20, and a high-voltage tower portion 11 that is formed to protrude from the lower portion. The ignition coil 1 has a high voltage terminal 40 electrically connected to the secondary coil 30 in the high voltage tower 11 and a spring 45 as a conductive member that electrically connects the high voltage terminal 40 and the ignition plug. Is disposed inside the plug boot portion 50 connecting the high-pressure tower portion 11 and the spark plug.

  In FIG. 3, the spring 45 is a conductive material having a small diameter at both ends and a larger diameter at both ends than the both ends, and an annular portion 45 a as a high voltage terminal fitting portion to be fitted to the high voltage terminal 40. Have. The plug boot portion 50 is made of a rubber elastic material, and both ends of the plug boot portion 50 have a small diameter portion 52a and a small diameter portion 52b that are smaller in diameter than the inside of the plug boot portion 50 on the ignition coil side and the ignition plug side, respectively. A projecting wall 53 is formed on the ignition coil side so as to project to the inner peripheral side of the opening of the high-pressure tower portion, and a housing portion 51 for housing the spring 45 is provided at the center. The accommodating portion 51 is configured by a space surrounded by the small diameter portion 52a, the small diameter portion 52b, and the inside of the plug boot portion 50, and the plug 45 is inserted by inserting the spring 45 from one end of the plug boot portion 50. The spring 45 is accommodated in the boot portion 50.

  In FIG. 4, the high-voltage terminal 40 is a cylindrical conductive material, and the outer circumference diameter of the cylinder is configured to be larger than the inner circumference diameter of the annular portion 45 a of the spring 45, and the tip gradually decreases in the direction outside the cylinder axis. A groove portion 41 fitted to the annular portion 45a of the spring 45 as a conductive member fitting portion to be fitted to a conductive member is provided on a part of the outer periphery of the cylinder, and has a tapered portion 42 which is small. The bottom is smaller than the outer diameter of the cylinder and has the same or slightly larger diameter as the inner diameter of the annular portion 45a. Further, since the annular portion 45a is formed with the tip of the spring 45 of the conductive spiral wire rod in an annular shape, the diameter of the annular portion 45a is reduced by a spring action when the inner diameter of the annular portion 45a is widened. Since a force can be applied in the following direction, the annular portion can be fitted into the groove portion on the outer periphery of the high voltage terminal of the tapered portion base.

  Since the spring 45 is accommodated in the accommodating portion 51 in advance, when the plug boot portion 50 is fitted to the high-pressure tower portion 11, the inner periphery of the annular portion 45 a is invited to the tapered portion 42 from the tip. Further, beyond the outer periphery of the tapered portion 42, the annular portion 45a is fitted into the groove portion 41 by a spring action. Therefore, the spring 45 and the high-voltage terminal 40 are mechanisms that can establish a reliable electrical and mechanical connection.

By applying the technique of the present invention as described above, the spring 45 is drawn into the tapered portion 42 of the high-voltage terminal 40 from the tip during assembly, so that the plug boot portion 50 protrudes toward the inner peripheral side of the high-voltage tower portion 11. The protruding wall 53 does not get caught by the spark plug side tip of the spring 45 and the spring 45 is not dropped from the high voltage terminal 40. The spring 45, since each other and the groove portion 41 of the high-voltage terminal 40 has a Kien annular portion 45a before fitting can be fitted with one touch. Therefore, a highly reliable ignition coil for an internal combustion engine can be provided with a simple configuration.

  The present invention is an ignition coil 1 in which a part of the case 10 is housed in a plug hole, and the rod-shaped central core 70, the primary coil 20, and the secondary coil 30 are electromagnetically coupled by an open magnetic path. However, the case may be an ignition coil in which most of the case is disposed outside the plug hole, and the square core, the primary coil, and the secondary coil are electromagnetically coupled by a closed magnetic circuit. The present invention relates to a structure of a plug boot portion of an ignition coil in which a high voltage generated from a secondary coil is distributed to a spark plug through a high-voltage terminal and a conductive member inside the plug boot portion. The case structure that accommodates the secondary coil and the magnetic path configuration that is electromagnetically coupled are not particularly limited.

  Further, in the plug boot portion for accommodating the conductive member and the high voltage terminal of the high voltage tower, when the conductive member is connected to the high voltage terminal, the conductive member fitting portion that fits the conductive member and the high voltage terminal are fitted. Any mechanism and assembly method may be used as long as the high-voltage terminal fitting portion can establish a reliable electrical and mechanical connection. The embodiments of the present invention are not particularly limited to the above-described embodiments. Based on the spirit of the present invention, various modifications and assembly methods that can be performed by those skilled in the art within the technical scope of the wording of the claims. It is also possible to implement with improved forms and assembly methods.

It is a figure of the ignition coil for internal combustion engines showing Example 1 to which art of the present invention is applied. It is an expanded sectional view of the plug boot part of FIG. It is an assembly drawing which accommodates a spring in the plug boot part showing Example 1 to which technology of the present invention is applied. It is an assembly figure of the plug boot part which accommodated the spring showing Example 1 to which technology of the present invention is applied, and a high voltage terminal. It is sectional drawing of the ignition coil for internal combustion engines by a prior art. It is an expanded sectional view of the plug boot part of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,100 Ignition coil 10,110 Case 11,111 High voltage tower part 20,120 Primary coil 21,121 Primary bobbin 30,130 Secondary coil 31,131 Secondary bobbin 40,140 High voltage terminal 41 Groove part 42 Tapered part 45 145 Spring 45a, 145a Annular part 50, 150 Plug boot part 51 Housing part 52a, 52b Small diameter part 53, 153 Protruding wall 60, 160 Primary connector 70, 170 Central core 141 Inner peripheral groove

Claims (1)

  A primary coil and a secondary coil arranged coaxially with the core are provided. The primary coil and the secondary coil are electromagnetically coupled via the core, and the primary coil is supplied with power and ignition. A primary connector for supplying a signal, a case for housing the primary coil and the secondary coil, a high-voltage tower portion protruding from the lower portion of the case, and the secondary coil disposed in the high-voltage tower portion and the electric An internal combustion engine comprising: a high-voltage terminal that is electrically connected; a conductive member that electrically connects the high-voltage terminal and the spark plug; and a plug boot portion made of an elastic material that connects the high-pressure tower portion and the spark plug. In the ignition coil, the plug boot portion includes an accommodating portion having both ends open and an opening diameter at both ends accommodating the conductive member having a smaller diameter than the inside of the plug boot portion, and the high voltage terminal is Cylinder A conductive member fitting portion that fits with the conductive member, and the conductive member fitting portion is formed on the outer periphery of the tapered portion and the high voltage terminal on the base of the tapered portion. A groove portion into which the annular portion is fitted, and the groove portion has a bottom that is smaller than the outer diameter of the cylinder and at least equal to or larger than the inner diameter of the annular portion, and the conductive member spirals the conductive wire. The processed spring has a high-voltage terminal fitting portion that is small in diameter at both ends and larger in diameter at both ends than the both ends, and is fitted with the high-voltage terminal. An ignition coil for an internal combustion engine, comprising an annular portion formed in an annular shape.

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