JP6606402B2 - Ignition coil for internal combustion engine and method for manufacturing the same - Google Patents

Description

  The present invention relates to an ignition coil for an internal combustion engine and a method for manufacturing the same.

  The demand for improved fuel economy and environmental performance of vehicles is increasing. For this reason, as an engine ignition system, an independent ignition system capable of changing the timing of ignition for each cylinder is prevailing so that gasoline combustion can be finely controlled. In this vehicle, an ignition coil is attached to each cylinder of the engine.

  In order to improve fuel efficiency and environmental performance, there is a strong demand for smaller and lighter engines. There is a strong demand for smaller and lighter ignition coils as well. On the other hand, in the ignition coil, a high voltage of several tens of kV is generated in the built-in secondary coil. The ignition coil is required to have excellent insulation performance. Ignition coils are required to be both compact and have good insulation performance. Furthermore, since an ignition coil is attached to each cylinder, there is a strong demand for cost reduction of the ignition coil.

  An ignition coil manufacturing method for the purpose of meeting these requirements is reported in Japanese Patent Application Laid-Open No. 2015-2257. In this manufacturing method, first, a secondary coil that generates a high voltage and its periphery are formed as a high-voltage part. In the formation of the high-voltage part body, the secondary coil is housed in the high-pressure part case. The gap between the case and the secondary coil is filled with epoxy resin. At this time, by using a high-quality epoxy resin having strong insulating properties, the high-voltage part is miniaturized and high withstand voltage performance is realized.

  In the above manufacturing method, next, the primary coil and the outer peripheral iron core are attached to the high-pressure member. Further, peripheral structures such as connectors and flanges are formed by injection molding. The primary coil, the outer peripheral iron core, and the peripheral structure have no portion where high voltage is generated. The formation of these portions does not require excellent insulation as in the high-pressure part. Attempts have been made to reduce the cost of the ignition coil by using an inexpensive resin in this injection molding.

JP-A-2015-2257

  In the method disclosed in Japanese Patent Laid-Open No. 2015-2257, the peripheral structure is formed by injection molding. In this step, a high-pressure part body to which a primary coil and an outer peripheral iron core are attached is placed in a mold, and a liquid resin is injected into the mold. At this time, the outer peripheral iron core may be displaced from the high-pressure member due to the pressure of the resin flowing. When the peripheral iron core is displaced, it may happen that the desired performance of the ignition coil cannot be obtained. When the outer peripheral core is displaced, it is possible that the outer peripheral core is exposed to the surface after injection molding. This can cause a short circuit.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an ignition coil and a method for manufacturing the same that have achieved reduction in size, good insulation, and cost reduction while suppressing deterioration in the performance of the ignition coil and short-circuiting in an outer peripheral iron core.

  An ignition coil according to the present invention includes a secondary coil and a high-pressure part body having a through-hole passing through the center of the secondary coil, a primary coil mounted on the high-pressure part body by being inserted into the through-hole, A ring-shaped outer peripheral core mounted on the outer periphery of the high-pressure part body and a peripheral structure formed around the high-pressure part body attached with the primary coil and the outer peripheral core are provided. Each of the outer peripheral cores is composed of a semi-ring-shaped first part and second part. When the outer peripheral iron core is viewed from the upper side, the tip of the first part has a first tip unevenness, and the tip of the second part has a second tip unevenness. The first tip unevenness and the second tip unevenness are fitted together. When the outer peripheral iron core is viewed from the upper side, the first inner surface of the first part has first inner unevenness, and the inner surface of the second part has second inner unevenness. When the high-pressure part is viewed from above, the outer peripheral surface of the high-pressure part is provided with a first outer unevenness and a second outer unevenness. The first inner unevenness and the first outer unevenness are fitted, and the second inner unevenness and the second outer unevenness are fitted.

  The ignition coil may further include an igniter mounted outside the first part. Preferably, the convex portion of the first tip unevenness is located outside the convex portion of the second tip unevenness.

  The present invention is an invention of a method of manufacturing an ignition coil for an internal combustion engine. This manufacturing method includes a step of obtaining a high-voltage part including a secondary coil and having a through-hole passing through the center of the secondary coil, and inserting the primary coil into the through-hole to attach the primary coil to the high-voltage part. A step of attaching a ring-shaped outer peripheral core to the outer periphery of the high-pressure part, and a step of forming a peripheral structure around the high-pressure part attached with the primary coil and the outer peripheral core. Each of the outer peripheral cores is composed of a semi-ring-shaped first part and second part. When the outer peripheral iron core is viewed from above, the tip of the first part is provided with a first tip unevenness, the tip of the second part is provided with a second tip unevenness, and the inner surface of the first part is A first inner unevenness is provided, and an inner surface of the second part is provided with a second inner unevenness. When the high-pressure part is viewed from above, the outer peripheral surface of the high-pressure part is provided with a first outer unevenness and a second outer unevenness. In the step of mounting the outer peripheral iron core, the first tip unevenness and the second tip unevenness are fitted, the first inner unevenness and the first outer unevenness are fitted, and the second inner unevenness The second outer irregularities are fitted together.

  In the ignition coil according to the present invention, an outer peripheral iron core is mounted around the high-pressure part body. The outer peripheral iron core is composed of a semi-ring-shaped first part and a second part. In this ignition coil, when the outer peripheral core is viewed from the upper side, the unevenness at the tip of the first part and the unevenness at the tip of the second part are fitted. The unevenness of the inner surface of the first part and the unevenness of the outer peripheral surface of the high-pressure part are fitted. The unevenness of the inner surface of the second part and the unevenness of the outer peripheral surface of the high-pressure part are fitted. By the combination of these fittings, it is effectively suppressed that the outer peripheral iron core is displaced from the high-pressure part in any of the upper, lower, left and right directions. This outer peripheral iron core is also prevented from being displaced from the high-pressure part in the subsequent step of forming the peripheral structure. In this ignition coil, performance degradation and short-circuiting of the outer peripheral iron core due to the positional deviation of the outer iron core are suppressed. In this ignition coil, downsizing, good insulation, and cost reduction are achieved while suppressing a decrease in performance and a short circuit in the outer peripheral iron core.

FIG. 1 is a perspective view illustrating an ignition coil according to an embodiment of the present invention. FIG. 2 is an exploded perspective view showing a high-pressure part of the ignition coil shown in FIG. FIG. 3 is an exploded perspective view showing a part of the coil structure of the ignition coil shown in FIG. FIG. 4 is a perspective view showing a coil structure of the ignition coil shown in FIG. FIG. 5 is an enlarged cross-sectional view taken along line VV in FIG. 6 is a cross-sectional view showing the coil structure of FIG. 4 together with a mold.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.

  The present invention relates to an ignition coil for an internal combustion engine and a method for manufacturing the same. FIG. 1 shows an ignition coil 2 according to an embodiment of the present invention. In FIG. 1, an arrow X represents the front of the ignition coil 2. The reverse is backwards. An arrow Y represents the right direction of the ignition coil 2. The reverse is the left direction. An arrow Z represents the upward direction of the ignition coil 2. The reverse is the downward direction. The arrows X, Y, and Z have the same meaning in FIGS. As shown in the figure, the ignition coil 2 includes a main body 4, a connector portion 6, and a flange portion 8.

  The main body 4 is located at the center of the ignition coil 2. As will be described later, the main body 4 includes a high-pressure part. The high voltage body includes a secondary coil. Furthermore, the main body 4 includes a primary coil, an iron core, and an igniter. As a result, a high voltage of several tens of kV is generated in the main body 4. The plug connection part 10 constitutes the lower part of the main body 4. Although not shown, a spark plug is connected to the tip of the plug connecting portion 10. The high voltage generated in the main body 4 is applied to the spark plug through the plug connection 10.

  The connector part 6 is located in front of the main body 4. The connector part 6 has a cylindrical shape. The connector portion 6 is opened at the front. The connector unit 6 includes a plurality of connector terminals 12 on the inner side. Although not shown, one of the connector terminals 12 is electrically connected to the igniter of the main body 4. The igniter is a switch for controlling the operation of the ignition coil 2. Although not shown, when the ignition coil 2 is mounted on a vehicle, the connector unit 6 is connected to a vehicle control unit (ECU). A control signal from the control device is sent to the igniter via the connector unit 6. Thereby, the control device controls the operation of the ignition coil 2. Thereby, a control device controls the timing which ignites gasoline.

  The flange portion 8 is located behind the main body 4. The flange portion 8 is provided with a hole 14 penetrating vertically. Although not shown, the ignition coil 2 is fixed to the engine by passing a bolt through the hole 14 and a hole provided in the engine. The ignition coil 2 is firmly fixed to the engine by the flange portion 8.

Below, the manufacturing method of this ignition coil 2 is demonstrated, and the structure of this ignition coil 2 is demonstrated collectively. The manufacturing method of the ignition coil 2 is as follows:
(1) A step of obtaining a high-pressure part,
(2) A step of attaching the primary coil to the high-pressure body,
(3) A step of attaching the outer peripheral iron core to the high-pressure body,
(4) A step of attaching the igniter to the high-pressure body,
And (5) forming a peripheral structure.

  FIG. 2 is an exploded perspective view of the high-pressure member 16 obtained in the step (1). In this step, first, the secondary coil 18, the cover 20, and the container 22 are prepared.

  The secondary coil 18 includes a bobbin 24 and a secondary wire (not shown). The bobbin 24 is cylindrical. The bobbin 24 includes a through hole 26 extending from the front to the rear. The bobbin 24 is made of an insulating resin. A typical material of the bobbin 24 is polyphenylene ether (PPE). The bobbin 24 has an annular protrusion 28 surrounding the opening of the through hole 26 on the front surface thereof. Although not shown, the bobbin 24 similarly has an annular protrusion 28 surrounding the opening of the through hole 26 on the rear surface. The bobbin 24 includes a plurality of ridges 30 around it. Although not shown in the drawing, a secondary wire is wound between the flanges 30 adjacent to each other. The number of windings of the secondary wire is appropriately determined depending on the voltage to be generated. The number of windings is typically 9000 to 20000. Thereby, the coil is formed. A typical material for the secondary wire is copper (Cu). Although not shown, the secondary coil 18 is provided with a terminal that is electrically connected to the secondary wire.

  The cover 20 includes an upper plate portion 32, a right plate portion 34, and a left plate portion 36. The cover 20 is open at the front, rear, and bottom. The cover 20 has a shape corresponding to the upper part of the secondary coil 18. The cover 20 is made of an insulating resin. As will be described later, the cover 20 covers the upper portion of the secondary coil 18. Although not shown in this figure, as will be described later, the right plate portion 34 and the left plate portion 36 are provided with irregularities for fitting with the irregularities of the external iron core.

  The container 22 includes a receiving portion 38, a wall portion 40, a flat plate portion 42, and a plug connection portion 44. As shown in the figure, the receiving portion 38, the wall portion 40, the flat plate portion 42, and the plug connecting portion 44 are integrally formed. The container 22 is made of an insulating resin. Examples of typical materials for the container 22 include polyphenylene sulfide (PPS) and PBT.

  The receiving portion 38 has a substantially arc shape that protrudes downward in a side view. The receiving portion 38 has a substantially circular shape when viewed from above. Although not shown, a recess is provided on the upper surface of the receiving portion 38.

  The flat plate portion 42 is provided on the upper surface of the receiving portion 38. When viewed from the front surface, the flat plate portion 42 protrudes left and right from the upper surface of the receiving portion 38. When viewed from the side, the flat plate portion 42 protrudes forward and backward from the upper surface of the receiving portion 38. Although not shown, a hole is provided in the center of the flat plate portion 42. Due to this hole, when the flat plate portion 42 and the receiving portion 38 are viewed from above, the recess of the receiving portion 38 is exposed. The flat plate portion 42 has a tongue portion 46 on the front side. The flat plate portion 42 has a protrusion 48 extending along the edge thereof.

  The wall portion 40 is provided on the upper surface of the flat plate portion 42. The wall portion 40 is provided so as to surround the recess of the receiving portion 38. A space formed by the recess of the receiving portion 38 and the wall portion 40 has a shape corresponding to the lower portion of the secondary coil 18. As will be described later, the lower portion of the secondary coil 18 is fitted into this space. Cutouts 50 are provided on the front and rear surfaces of the wall 40. The notch 50 corresponds to the shape of the lower portion of the annular protrusion 28 of the secondary coil 18. The notch 50 prevents the wall portion 40 from closing the through hole 26 of the secondary coil 18 when the secondary coil 18 is fitted into the space formed by the recess of the receiving portion 38 and the wall portion 40. Has been. The through hole 26 of the secondary coil 18 forms a through hole of the high voltage part 16.

  The plug connection part 44 is located below the receiving part 38. The plug connection part 44 constitutes the plug connection part 10 of the high-pressure part 16 described above. Although not shown, the plug connection portion 44 includes a high-voltage terminal therein. This high voltage terminal is connected to the terminal of the secondary coil 18. Although not shown, when the ignition coil 2 is mounted on the vehicle, the high-voltage terminal is connected to an ignition plug. As a result, the high voltage generated in the secondary coil 18 is applied to the spark plug.

  Next, in the step (1), the secondary coil 18, the cover 20, and the container 22 are combined. The lower portion of the secondary coil 18 is fitted into a space formed by the recess of the receiving portion 38 and the wall portion 40. The annular protrusion 28 of the secondary coil 18 is fitted into the notch 50 of the wall 40. The contact portion between the annular protrusion 28 and the wall 40 is firmly joined by ultrasonic welding. A cover 20 is placed over the secondary coil 18. The lower ends of the right plate portion 34 and the left plate portion 36 of the cover 20 are in contact with the upper ends of the wall portions 40 of the container 22. At this time, there is a gap between the upper plate portion 32 of the cover 20 and the annular protrusion 28 of the secondary coil 18. The secondary coil 18 is accommodated in a space (accommodating space) formed by the cover 20 and the recess 40 of the wall portion 40 and the receiving portion 38 of the accommodating body 22. The cover 20 and the container 22 constitute a high-pressure part case. The secondary coil 18 is accommodated in the high-voltage part case.

  In the step (1), the gap remaining in the accommodation space is filled with resin. That is, a gap between the secondary coil 18 and the high voltage part case is filled. Although not shown, liquid epoxy resin is poured from the gap between the upper plate portion 32 of the cover 20 and the annular protrusion 28. An epoxy resin is filled in the gap in the accommodation space. After filling, the epoxy resin is heat cured. Thereby, the high-pressure part 16 is obtained. FIG. 3 shows the high pressure member 16 obtained. In the high voltage | pressure part body 16, a secondary wire is insulated from the exterior except the part connected to a high voltage terminal.

  As this epoxy resin, a resin having better insulation performance than a resin for constituting a peripheral structure described later is selected. Thereby, in this high voltage | pressure part body 16, it becomes possible to insulate a high voltage part with a small volume. This contributes to downsizing of the ignition coil 2. Thereby, miniaturization and excellent insulation performance are realized.

  As this epoxy resin, one having a lower viscosity than the resin for constituting the peripheral structure is selected. Thereby, resin can be spread to every corner of the gap remaining in the accommodation space. Furthermore, it is suppressed that a void remains in resin. Thereby, in the high voltage | pressure body 16, the high pressure | voltage resistant and high quality insulation performance is implement | achieved.

  As described above, in this method, the high-pressure member 16 does not include a part having a large heat capacity such as an iron core. In the thermosetting treatment of the epoxy resin, the resin can be uniformly thermoset with a small amount of heat. With this method, high-quality thermal curing can be realized efficiently.

  In the step (2), first, the primary coil 52 is prepared. FIG. 3 shows this state. The primary coil 52 includes an I-shaped iron core 54, an insulator 56, a primary wire 58 and a frame 60. The I-shaped iron core 54 has a prismatic shape extending in the front-rear direction. I-shaped iron core 54 is typically made of a laminated silicon steel plate. The insulator 56 covers the side surface of the I-shaped iron core 54. The insulator 56 insulates the I-shaped iron core 54 from the primary wire 58. The primary wire 58 is wound around the insulator 56. The number of windings of the primary wire 58 is appropriately determined depending on the voltage to be generated. The number of windings is typically 100 to 250. Thereby, the coil is formed. The frame 60 is attached to the front surface of the I-shaped iron core 54. The frame 60 is an insulator. The frame 60 includes a terminal portion 62 at its upper end. Both ends of the primary wire 58 are drawn to the terminal portion 62, respectively.

  In the step (2), the primary coil 52 is inserted into the through hole of the high-voltage part 16. That is, the primary coil 52 is inserted into the through hole 26 of the secondary coil 18. The rear part of the primary coil 52 is inserted from the front of the through hole 26. As a result, the primary coil 52 is attached to the high-voltage unit 16. The frame 60 is positioned so as to close the opening in front of the through hole 26. The rear end of the I-shaped iron core 54 extends to an opening behind the through hole 26. The I-shaped iron core 54 is also the iron core of the secondary coil 18.

  In the step (3), the outer peripheral iron core 64 is prepared. The outer peripheral iron core 64 is typically made of silicon steel. The outer peripheral iron core 64 has a ring shape. In the outer peripheral iron core 64, the inside of the ring is the inside and the outside of the ring is the outside. As shown in FIG. 3, each of the outer peripheral cores 64 includes a first part 66 and a second part 68 each having a semi-ring shape.

  In the step (3), the outer peripheral iron core 64 is attached to the outer periphery of the high-pressure part body 16. FIG. 4 shows a state in which the outer peripheral iron core 64 is attached to the high-pressure part body 16. In this figure, an igniter 70 described later is also mounted. As shown in the figure, the first part 66 is mounted so as to surround the front part of the high-pressure part 16. The first part 66 covers the frame 60 from the front. The second part 68 is mounted so as to surround the rear part of the high-pressure part body 16. At this time, the second portion 68 and the rear end of the I-shaped iron core 54 are in contact with each other. The first part 66 and the second part 68 are disposed above the flat plate part 42 of the container 22. The first part 66 and the second part 68 are disposed between the wall part 40 and the protrusion part 48.

  FIG. 5 is an enlarged cross-sectional view taken along line VV in FIG. In this sectional view, only the I-shaped iron core 54, the outer peripheral iron core 64, and the cover 20 are shown. In FIG. 5, the arrow X represents the front of the ignition coil 2. The reverse is backwards. An arrow Y represents the right direction of the ignition coil 2. The reverse is the left direction.

  As shown in FIG. 5, when viewed from above, the two tips of the first portion 66 are each provided with first tip irregularities 87. In this figure, each of the first tip irregularities 87 is composed of one convex portion 88 and one concave portion 90. When viewed from above, the two tips of the second part 68 are each provided with a second tip irregularity 91. In this figure, each second tip unevenness 91 is composed of one convex portion 92 and one concave portion 94. As shown in the figure, the first tip unevenness 87 and the second tip unevenness 91 are fitted. That is, the convex portion 88 of the first tip concavo-convex 87 enters the concave portion 94 of the second tip concavo-convex 91. The convex portion 92 of the second tip concavo-convex 91 enters the concave portion 90 of the first tip concavo-convex 87. The first part 66 and the second part 68 are connected by fitting the first tip unevenness 87 and the second tip unevenness 91 together.

  The shape of the first tip unevenness and the shape of the second tip unevenness are not limited to the shapes shown in FIG. What is necessary is just to fit the 1st front-end | tip unevenness | corrugation and the 2nd front-end | tip unevenness | corrugation. For example, the front end of the first part 66 is provided with one convex part located at the center and two concave parts located on both sides thereof, and the front end of the second part 68 is located on one concave part and both sides thereof. You may provide two convex parts.

  As shown in FIG. 5, the outer peripheral surface of the high-pressure member 16 includes first outer irregularities 71 and 75 and second outer irregularities 73 and 77. In other words, the outer surface of the cover 20 includes first outer irregularities 71 and 75 and second outer irregularities 73 and 77. In this embodiment, the first outer unevenness 71 of the right plate portion 34 of the cover 20 is constituted by one first convex portion 72. The second outer unevenness 73 of the right plate portion 34 is composed of one second convex portion 74. The first outer unevenness 75 of the left plate portion 36 is composed of one first convex portion 76. The second outer unevenness 77 of the left plate portion 36 is composed of one second convex portion 78.

  The inner surface of the first part 66 includes first inner irregularities 79 and 81. As shown in the drawing, in this embodiment, the first inner concave / convex portion 79 on the right inner surface is constituted by one first concave portion 80. The first inner concave / convex portion 81 on the left inner surface is composed of one first concave portion 82. The first outer irregularities 71 and 75 and the first inner irregularities 79 and 81 are fitted. That is, the first convex portion 72 of the right plate portion 34 is fitted in the first concave portion 80 on the right side of the first portion 66. The first convex portion 76 of the left plate portion 36 is fitted in the first concave portion 82 on the left side of the first portion 66.

  The shape of the first inner unevenness and the shape of the first outer unevenness are not limited to the shapes shown in FIG. What is necessary is just to fit the 1st inner side unevenness | corrugation and the 1st outer side unevenness | corrugation. For example, the first inner unevenness may be convex and the first outer unevenness may be concave. The first inner unevenness may include a convex shape and a concave shape, and the first outer unevenness may include a convex shape and a concave shape. The first inner unevenness may include a plurality of concave shapes or convex shapes, and the first outer unevenness may include a plurality of concave shapes or convex shapes.

  The inner surface of the second part 68 includes second inner irregularities 83 and 85. As shown in the figure, in this embodiment, the second inner concave / convex portion 83 on the inner surface on the right side of the second portion 68 is constituted by one second concave portion 84. The second inner concave / convex portion 85 on the left inner surface is composed of one second concave portion 86. The second outer irregularities 73 and 77 and the second inner irregularities 83 and 85 are fitted. That is, the second convex portion 74 of the right plate portion 34 is fitted in the second concave portion 84 on the right side of the second portion 68. The second convex part 78 of the left plate part 36 is fitted in the second concave part 86 on the left side of the second part 68.

  The shape of the second inner unevenness and the shape of the second outer unevenness are not limited to the shapes shown in FIG. The second inner unevenness and the second outer unevenness may be fitted together. For example, the second inner unevenness may be convex and the second outer unevenness may be concave. The second inner unevenness may include a convex shape and a concave shape, and the second outer unevenness may include a convex shape and a concave shape. The second inner unevenness may include a plurality of concave shapes or convex shapes, and the second outer unevenness may include a plurality of concave shapes or convex shapes.

  As described above, the first tip unevenness 87 and the second tip unevenness 91 are fitted together. The fitting of the first tip concavo-convex 87 and the second tip concavo-convex 91 suppresses the outer peripheral iron core 64 from shifting vertically from the high-pressure part 16. Further, the first outer unevenness 71 and 75 and the first inner unevenness 79 and 81 are fitted. The fitting of the first outer irregularities 71 and 75 and the first inner irregularities 79 and 81 prevents the first part 66 from shifting from the high-pressure part body 16 to the left and right. The second outer irregularities 73 and 77 and the second inner irregularities 83 and 85 are fitted. The fitting of the second outer irregularities 79 and 81 and the second inner irregularities 83 and 85 suppresses the second part 68 from shifting from the high-pressure part body 16 to the left and right. By combining these fittings, it is possible to effectively prevent the outer peripheral iron core 64 from being displaced from the high-pressure part 16 in any of the upper, lower, left and right directions. The outer peripheral core 64 is suppressed from being displaced from the high-pressure part 16 also in the process of forming a peripheral structure later. In the ignition coil 2, performance degradation and short-circuiting of the outer peripheral iron core 64 due to the displacement of the outer peripheral iron core 64 are suppressed.

  In FIG. 5, the convex portion 88 of the first tip concavo-convex 87 is located outside the convex portion 92 of the second tip concavo-convex 91. That is, at the joint between the right end of the first portion 66 and the right end of the second portion 68, the convex portion 88 of the first tip unevenness 87 is positioned on the right side of the convex portion 92 of the second tip unevenness 91. is doing. At the joint between the left end of the first portion 66 and the left end of the second portion 68, the tip of the convex portion 88 of the first tip unevenness 87 is located on the left side of the convex portion 92 of the second tip unevenness 91. ing. Thus, it is preferable that the convex portion 88 of the first tip concavo-convex 87 is located outside the convex portion 92 of the second tip concavo-convex 91. As will be described later, the first part 66 is sandwiched between the igniter 70 and the frame 60 in front of the high-pressure part body 16. In the step of forming the peripheral structure, the first part 66 is less likely to be displaced than the second part 68. The convex part 88 of the first part 66 that is difficult to shift suppresses the convex part 92 of the second part 68 from the outside. The second portion 68 is not easily displaced. By doing in this way, it is suppressed more effectively that this peripheral iron core 64 shifts from high voltage | pressure part body 16. FIG.

  Unlike the case of FIG. 5, the first tip 66 and the second portion 68 may have a plurality of convex portions. In this case, it is only necessary that at least one convex portion of the first tip unevenness is located outside the convex portion of the second tip unevenness. The convex portion of the first tip unevenness suppresses the convex portion of the second tip unevenness from the outside. Thereby, it is suppressed more effectively that the outer periphery iron core 64 shifts | deviates from the high voltage | pressure part body 16. FIG.

  In the step (4), an igniter 70 is prepared. The igniter 70 is a switch that switches between conduction and disconnection of the current of the primary coil 52. In this step, the igniter 70 is attached to the high-pressure part 16. FIG. 4 shows a state after the igniter 70 is mounted. As shown in the figure, the igniter 70 is disposed in front of the high-pressure part 16. The igniter 70 is disposed outside the first part 66. The igniter 70 is disposed on the flat plate portion 42 of the container 22. The first part 66 is sandwiched between the igniter 70 and the frame 60 in front of the high-pressure part 16.

  Here, the component mounted on the high-pressure unit 16 is referred to as a coil assembly. In this embodiment, the primary coil 52, the outer peripheral core 64, and the igniter 70 are a coil assembly. A structure in which a coil assembly is mounted on the high-pressure unit 16 is referred to as a coil structure 96. In FIG. 4, a coil structure 96 is shown.

  In the step (5), a peripheral structure is formed around the coil structure 96. In this embodiment, the peripheral structure is formed by injection molding. The state of this process is shown in FIG. In the example of this figure, an outer shell for insulating the coil assembly is formed by injection molding. In this process, the coil structure 96 is placed in the cavity 100 of the mold 98. The shape of the high-pressure part 16 below the flat plate part 42 is the same as the shape of the lower part of the cavity 100. Above the flat plate portion 42, a gap is provided between the coil structure 96 and the mold 98. A liquid resin 102 is injected into the gap using a plunger. After filling, the resin 102 is thermoset. Thereby, an outer shell part is formed. The outer shell portion covers the upper side of the flat plate portion 42 of the coil structure 96. The coil structure 96 and the outer shell portion covering it correspond to the main body 4 in FIG. Exemplary resins 102 include phenolic resins, unsaturated polyesters, and epoxy resins.

  Although not shown, in the step (5), injection molding is further performed on the coil structure 96 and the outer shell. Thereby, the connector part 6 and the flange part 8 are formed. As the peripheral structure, an outer shell portion, a connector portion 6 and a flange portion 8 are formed. Thereby, the ignition coil 2 of FIG. 1 is obtained.

  In the formation of the peripheral structure, there is no place where high voltage is generated unlike the secondary coil 18. The resin 102 for forming the peripheral structure is not required to have insulating performance as much as the resin used in the step (1). A cheaper resin 102 can be selected. In this method, the manufacturing cost can be reduced as compared with the method in which the periphery of the secondary coil 18 and the peripheral structure are injection-molded using a resin having high insulation performance at a time. In this method, superior insulation performance is realized as compared with a method in which the periphery of the secondary coil 18 and the peripheral structure are injection molded using an inexpensive resin having low insulation performance. With this method, the ignition coil 2 having excellent insulation performance at low cost can be obtained.

  As described above, high insulation performance is not required in forming the peripheral structure. This relaxes restrictions such as time in the thermosetting process. Formation of this peripheral structure is easy.

  In the above, the thermosetting resin 102 was used to form the peripheral structure. A thermoplastic resin may be used to form the peripheral structure. Moreover, in said embodiment, the outer shell part, the connector part 6, and the flange part 8 were formed separately. All of these may be formed by a single injection molding.

  In the above embodiment, in the step (5), the peripheral structure is formed by injection molding. The peripheral structure may not be formed by injection molding. A “peripheral cover” in which the outer shell part, the connector part 6 and the flange part 8 are integrated may be separately created, and the peripheral structure may be formed by covering the peripheral cover on the coil structure 96.

  In the above embodiment, the igniter 70 is attached to the high-pressure part 16 in the step (4). When the peripheral structure is formed by the peripheral cover, the igniter 70 may be attached to the peripheral cover. In this case, the igniter 70 becomes a part of the peripheral structure. In this case, the step (4) does not exist.

  Hereinafter, the effects of the present invention will be summarized.

  In the manufacture of conventional ignition coils, first, a secondary coil that generates a high voltage and its surroundings are created as high-voltage parts, and then the primary coil and outer peripheral iron core are mounted on the high-voltage parts to form a coil structure. There is a method of creating and finally forming a peripheral structure around the coil structure. In this method, a high-pressure part is produced by using a high-quality epoxy resin having a strong insulating property, thereby realizing downsizing and high withstand voltage performance. The manufacturing cost can be reduced by forming the peripheral structure by injection molding using an inexpensive resin.

  However, in this method, when the peripheral structure is formed, the outer peripheral iron core may be displaced from the high-pressure part. For example, when the peripheral structure is formed by injection molding, the coil structure is placed in a mold having a cavity. A liquid resin is injected between the coil structure and the mold. Due to the pressure at which the resin flows, the outer peripheral iron core is displaced from the high pressure member. When the peripheral iron core is displaced, the desired ignition coil performance may not be obtained. When the outer peripheral core is displaced, it is possible that the outer peripheral core is exposed to the surface after injection molding. This can cause a short circuit.

  In forming the peripheral structure, there is a method in which a peripheral cover is prepared separately and the peripheral cover is placed on the coil structure. Even in this case, it is possible that the outer peripheral iron core is displaced from the high-pressure part when the peripheral cover is attached.

  The ignition coil 2 according to the present invention is manufactured by creating the high-voltage part 16, attaching the primary coil 52 and the outer peripheral iron core 64 to the high-voltage part 16, and forming a peripheral structure around them. As described above, as a result, the ignition coil 2 is reduced in size, good insulative properties, and low in cost. Furthermore, in the ignition coil 2 according to the present invention, when the outer peripheral iron core 64 is viewed from the upper side, the first front end unevenness 87 at the front end of the first portion 66 and the second front end unevenness at the front end of the second portion 68 of the outer peripheral iron core 64. 91 is fitted. The first inner irregularities 79 and 81 on the inner surface of the first part 66 and the first outer irregularities 71 and 75 on the outer peripheral surface of the high-pressure part 16 are fitted together. The second inner irregularities 83 and 85 on the inner surface of the second part 68 and the second outer irregularities 73 and 77 on the outer peripheral surface of the high-pressure part 16 are fitted together. The combination of these fittings effectively suppresses the outer peripheral iron core 64 from shifting from the high-pressure part 16 in any of the upper, lower, left and right directions. The outer peripheral core 64 is suppressed from being displaced from the high-pressure part 16 also in the process of forming a peripheral structure later. In the ignition coil 2, performance degradation and short-circuiting of the outer peripheral iron core 64 due to the displacement of the outer peripheral iron core 64 are suppressed. In the ignition coil 2, a reduction in performance and a short circuit at the outer peripheral iron core 64 are suppressed, and a reduction in size, good insulation, and cost reduction are achieved. From the above, the superiority of the present invention is clear.

  The manufacturing method described above is used for manufacturing ignition coils for various internal combustion engines.

2 ... Ignition coil 4 ... Body 6 ... Connector part 8 ... Flange part 10, 44 ... Plug connection part 12 ... Connector terminal 14 ... Hole 16 ... High pressure part 18 ... Secondary coil 20 ... Cover 22 ... Housing 24 ... Bobbin 26 ... Through-hole 28 ... Annular projection 30 ... ３２ 32 ... Upper plate 34 ...・ ・ Right plate part 36 ... Left plate part 38 ... Receiving part 40 ... Wall part 42 ... Plate part 46 ... Tongue part 48 ... Protrusion part 50 ... Notch 52 ..Primary coil 54 ... I-shaped iron core 56 ... Insulator 58 ... Primary wire 60 ... Frame 62 ... Terminal part 64 ... Outer iron core 66 ... First part 68 ... -Second part 70 ... Igniter 71, 75 ... First outer surface unevenness 72, 76 ... First convex part 73, 77 ... second outer irregularities 74 and 78 ... second convex portion 79, 81 ... first inner uneven 80,82 ... first recess
83, 85 ... second inner unevenness 84, 86 ... second recess 87 ... first tip unevenness 88 ... first tip unevenness 90 ... first tip unevenness 91 ··· Second tip irregularities 82 ··· Convex portions of the second tip irregularities 94 ··· Concavities and recesses of the second tip portion 96 · · · Coil structure 98 · · · Mold 100 · · · Cavity 102 · · · Resin

Claims (3)

A high-pressure part including a secondary coil and having a through-hole passing through the center of the secondary coil;
A primary coil attached to the high-pressure body by being inserted into the through-hole,
A ring-shaped outer peripheral core mounted on the outer periphery of the high-pressure body,
And a peripheral structure formed around the high-pressure part body to which the primary coil and the outer peripheral iron core are attached,
Each of the outer peripheral cores is composed of a semi-ring-shaped first part and a second part,
When the outer peripheral iron core is viewed from the upper side, the tip of the first part is provided with a first tip unevenness, and the tip of the second part is provided with a second tip unevenness,
The first tip unevenness and the second tip unevenness are fitted,
When the outer peripheral core is viewed from above, the inner surface of the first part is provided with a first inner unevenness, and the inner surface of the second part is provided with a second inner unevenness,
When the high-pressure part is viewed from above, the outer peripheral surface of the high-pressure part is provided with a first outer unevenness and a second outer unevenness,
An ignition coil for an internal combustion engine, wherein the first inner unevenness and the first outer unevenness are fitted, and the second inner unevenness and the second outer unevenness are fitted. An igniter mounted on the outside of the first part;
The ignition coil according to claim 1, wherein the convex portion of the first tip unevenness is positioned outside the convex portion of the second tip unevenness. A method for producing an ignition coil for an internal combustion engine, comprising:
Obtaining a high-pressure part including a secondary coil and having a through-hole passing through the center of the secondary coil;
A step of attaching the primary coil to the high-voltage body by inserting the primary coil into the through hole;
Attaching a ring-shaped outer peripheral core to the outer periphery of the high-pressure part;
And a step of forming a peripheral structure around the high-pressure part mounted with the primary coil and the outer peripheral iron core,
The outer core is composed of a semi-ring-shaped first part and a second part,
When the outer peripheral iron core is viewed from the upper side, the tip of the first part is provided with a first tip unevenness, the tip of the second part is provided with a second tip unevenness, and the inner surface of the first part is It has a first inner unevenness, the inner surface of the second part is provided with a second inner unevenness,
When the high-pressure part is viewed from above, the outer peripheral surface of the high-pressure part is provided with a first outer unevenness and a second outer unevenness,
In the process of mounting the outer peripheral iron core,
The first tip unevenness and the second tip unevenness are fitted, the first inner unevenness and the first outer unevenness are fitted, and the second inner unevenness and the second outer unevenness are fitted. A method for manufacturing an ignition coil.

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