JP2005223210A - Ignition coil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ignition coil which can be miniaturized by reducing the cross section of the core. <P>SOLUTION: The ignition coil has the core, a primary spool, a primary coil, a secondary spool and a secondary coil. In the core, a band-like directional silicon steel plate which is long in the easy magnetization direction is laminated in a plate thickness direction with its easy magnetization direction uniform, and furthermore, it is formed into a square shape, by bending along an easy magnetization direction. Consequently, the ignition coil can be made compact, by reducing the core by raising the saturation magnetic flux density of the core. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ignition coil for an internal combustion engine.

Conventionally, as an ignition coil for an internal combustion engine, for example, there is an ignition coil disclosed in JP-A-2002-164236. The ignition coil includes a coil core, a primary coil, and a secondary coil. The coil core is an annular iron core, and is formed with the legs of two U-shaped iron cores configured by laminating silicon steel plates facing each other. The primary coil is wound around the coil core. The secondary coil is concentrically wound around the outer periphery of the primary coil. When the current flows through the primary coil, the primary coil generates a magnetic flux. This magnetic flux flows through the coil core and interlinks with the secondary coil. Thereby, a high voltage is induced in the secondary coil.
JP 2002-164236 A

  However, in such an ignition coil, the magnetic flux generated by the primary coil flows in an annular shape along the shape of the coil core in the silicon steel sheet constituting the coil core. For this reason, when using a core laminated with a punched silicon steel sheet, the silicon steel sheet does not have an easy magnetization direction that can be easily magnetized, and can flow a magnetic flux equally in all directions. Silicon steel sheets have been used. However, this non-oriented silicon steel sheet has a lower saturation magnetic flux density than a directional silicon steel sheet having an easy magnetization direction. I can't make it smaller.

  This invention is made | formed in view of such a situation, and it aims at providing the ignition coil which can be reduced in size by reducing the cross-sectional area of a core.

  Therefore, as a result of intensive research and trial and error to solve this problem, the present inventor has bent the magnetic piece having an easy magnetization direction along the easy magnetization direction to constitute the core, thereby breaking the core. The inventors have come up with the idea that the area can be reduced and have completed the present invention.

  That is, the ignition coil according to claim 1 includes a core that forms a magnetic path, a primary coil that is wound around the core and generates a magnetic flux in the core by flowing current, and around the core. An ignition coil including a secondary coil that is wound and has a secondary coil that induces a voltage by a magnetic flux flowing through the core generated by the primary coil. Further, the core easily forms a magnetic plate having an easy magnetization direction. It is characterized in that it is laminated in the plate thickness direction with the magnetization direction aligned, and is bent along the easy magnetization direction.

  The ignition coil according to a second aspect is the ignition coil according to the first aspect, further characterized in that the core is rounded and bent.

  The ignition coil according to claim 3 is the ignition coil according to claim 1 or 2, and further, the core is disposed adjacent to the first core having a square shape and the first core. It is characterized by comprising a B-shaped second core.

  The ignition coil according to claim 4 is the ignition coil according to claim 1 or 2, and further, the core is integrally connected to the first core portion having a square shape and the first core portion. It is characterized by comprising a second core portion having a square shape disposed adjacent to the first core portion.

  According to the ignition coil of the first aspect, the core can be constituted only by the magnetic plate having an easy magnetization direction that is easily magnetized. The magnetic plate having the easy magnetization direction has a higher saturation magnetic flux density than the magnetic plate having no easy magnetization direction. Therefore, when the same magnetic flux flows, a core made of a magnetic plate having an easy magnetization direction can reduce the cross-sectional area of the core perpendicular to the flow direction of the magnetic flux compared to a core made of a magnetic plate having no easy magnetization direction. it can. Therefore, when the magnetic flux generated by the primary coil flows along this easy magnetization direction, the core can be made smaller and the ignition coil can be made smaller.

  According to the ignition coil of the second aspect, the core can be rounded and bent. By the way, when a large stress is applied to the magnetic plate constituting the core, the magnetic characteristics of the magnetic plate are changed and the magnetic flux hardly flows. Therefore, by rounding the core and gently bending it, changes in the magnetic properties of the magnetic plate can be suppressed, and a sufficient magnetic flux can flow.

  According to the ignition coil of the third aspect, the core can be constituted by the first core and the second core having a square shape disposed adjacent to each other. Furthermore, the magnetic flux generated by the primary coil can be divided and passed between the first core and the second core. Therefore, by changing the arrangement direction of the first core and the second core, it is possible to freely change the shape of the core according to restrictions when the vehicle is mounted. For example, the second core is disposed adjacent to the first core so that the surface surrounded by the magnetic plate of the second core is perpendicular to the surface surrounded by the magnetic plate of the first core. Thus, the core can be formed into an optimal shape for mounting on a vehicle. Moreover, the magnetic flux which flows into a 1st core and a 2nd core becomes small, and the cross-sectional area of a 1st core and a 2nd core can be made small. Thereby, the dimension of the lamination direction of a 1st core and a 2nd core can be made small, and the dimension of the core of a right angle direction can be made small with respect to the adjacent direction of a 1st core and a 2nd core.

  According to the ignition coil of the fourth aspect, the core can be constituted by the first core portion and the second core portion that are integrally connected and arranged adjacent to each other. Furthermore, the magnetic flux generated by the primary coil can be divided into the first core portion and the second core portion. Therefore, the number of parts can be reduced by integrally connecting the first core portion and the second core portion, and the efficiency of the assembling work can be improved. Moreover, the magnetic flux which flows into a 1st core part and a 2nd core part becomes small, and the cross-sectional area of a 1st core part and a 2nd core part can be made small. Thereby, the dimension of the lamination direction of a 1st core part and a 2nd core part can be made small, and the dimension of the core of a right angle direction can be made small with respect to the adjacent direction of a 1st core part and a 2nd core part.

  The present embodiment shows an example in which the ignition coil according to the present invention is applied to a vehicle ignition coil that supplies a high voltage to an ignition plug provided in each cylinder.

(First embodiment)
FIG. 1 is a sectional view in the axial direction of the ignition coil according to the first embodiment, and FIG. 2 is a perspective view of the core. Then, with reference to FIGS. 1 and 2, the structure, operation, and effect will be specifically described in this order.

  First, a specific structure will be described. As shown in FIG. 1, the ignition coil 1 includes a core 2, a primary spool 3, a primary coil 4, a secondary spool 5, and a secondary coil 6. As shown in FIG. 2, the core 2 is formed by laminating band-shaped directional silicon steel plates that are long in the easy magnetization direction, aligning the easy magnetization directions in the thickness direction, and bending the easy direction along the easy magnetization direction. Shaped in a letter shape. The cross-sectional area of the core 2 perpendicular to the easy magnetization direction is set to a sufficient size to allow a magnetic flux generated by a primary coil 4 described later to flow. The first magnetic leg 2a, the second magnetic leg 2b, a first magnetic coupling part 2c that magnetically connects between the opposing shaft ends, and a second magnetic coupling part 2d, A gap 2e is provided at the center of the first magnetic leg 2a. The gap 2e is set to an optimum dimension so that the output voltage of the secondary coil 6 becomes a predetermined voltage.

  Returning to FIG. As shown in FIG. 1, the primary spool 3 is a rectangular tube body having a rectangular tube portion and end walls extending in the diameter-expanding direction from both axial end portions of the rectangular tube portion. Made of insulating material. And it arrange | positions so that the outer peripheral surface of the 1st magnetic leg 2a of the core 2 may be covered. The primary coil 4 is a winding wound around the outer peripheral surface of the rectangular tube portion of the primary spool 3. The secondary spool 5 is a rectangular tube body having a rectangular tube portion and end walls extending in the diameter increasing direction from both shaft end portions of the rectangular tube portion, and is made of, for example, an insulating material such as resin. . And it is concentrically arranged on the outer peripheral side of the primary coil 4. The secondary coil 6 is a winding wound around the outer peripheral surface of the rectangular tube portion of the secondary spool 5. The primary spool 3 wound with the primary coil 4 and the secondary spool 5 wound with the secondary coil 6 are fixed to the core 2 with a resin 7.

  Next, a specific operation will be described. An igniter (not shown) supplies a primary current to the primary coil 4 based on an ignition timing signal from an ECU (not shown). When the primary current flows, the primary coil 4 generates magnetic flux in the core 2. This magnetic flux is linked to the secondary coil 6 by flowing from the first magnetic leg 2a to the first magnetic leg 2a via the first magnetic coupling part 2c, the second magnetic leg 2b, and the second magnetic coupling part 2d. For this reason, a high voltage is induced in the secondary coil 6. This high voltage is applied to a spark plug (not shown), and the spark plug generates a spark in the gap between its electrodes.

  Finally, specific effects will be described. According to the first embodiment, the ignition coil 1 can form the core 2 only with a directional silicon steel plate having an easy magnetization direction that is easy to be magnetized. Further, the magnetic flux generated by the primary coil 4 can flow along this easy magnetization direction. By the way, a directional silicon steel sheet having an easy magnetization direction has a higher saturation magnetic flux density than a non-oriented silicon steel sheet having no easy magnetization direction. Therefore, when the same magnetic flux flows, the core 2 made of a directional silicon steel plate can have a smaller cross-sectional area of the core 2 perpendicular to the direction in which the magnetic flux flows than a core made of a non-oriented silicon steel plate. Therefore, the core 2 can be made small and the ignition coil 1 can be miniaturized.

(Second Embodiment)
Next, FIG. 3 shows an axial sectional view of the ignition coil in the second embodiment, and FIG. 4 shows a perspective view of the core. Here, only a different part from the ignition coil in 1st Embodiment is demonstrated, and description except a required part is abbreviate | omitted about a common part. In addition, the same code | symbol is attached | subjected and demonstrated to the element same as the said embodiment.

  First, a specific structure will be described with reference to FIGS. The core 2 is formed in a square shape by laminating directional silicon steel sheets having a strip shape long in the easy magnetization direction in the thickness direction with the easy magnetization direction aligned, and further bending along the easy magnetization direction. . The first magnetic leg 2a, the second magnetic leg 2b, a first magnetic coupling part 2c that magnetically connects between the opposing shaft ends, and a second magnetic coupling part 2d, The first magnetic leg 2a has a gap 2e on the second magnetic joint portion 2d side. The gap 2e is set to an optimum dimension so that the output voltage of the secondary coil 6 becomes a predetermined voltage. Further, the core 2 is rounded and bent.

  Next, specific effects will be described. According to the second embodiment, the ignition coil 1 can be bent by rounding the core 2. By the way, when a large stress is applied to the silicon steel plate constituting the core 2, the magnetic properties of the silicon steel plate change and the magnetic flux hardly flows. Therefore, by rounding the core 2 and bending it gently, changes in the magnetic properties of the silicon steel sheet can be suppressed and a sufficient magnetic flux can be passed.

(Third embodiment)
Next, FIG. 5 shows an axial sectional view of an ignition coil in the third embodiment, and FIG. 6 shows a perspective view of a core. Here, only a different part from the ignition coil in 1st and 2nd embodiment is demonstrated, and description except a required part is abbreviate | omitted about a common part. In addition, the same code | symbol is attached | subjected and demonstrated to the element same as the said embodiment.

  First, a specific structure will be described with reference to FIGS. The core 2 is formed in a square shape by laminating directional silicon steel sheets having a strip shape long in the easy magnetization direction in the thickness direction with the easy magnetization direction aligned, and further bending along the easy magnetization direction. The first core 20 and the second core 21 are configured. The first core 20 and the second core 21 are respectively a first magnetic leg 20a, 21a, a second magnetic leg 20b, 21b, and a first magnetic link that magnetically connects between the opposing shaft ends. It consists of joint parts 20c, 21c and second magnetic joint parts 20d, 21d, and has gaps 20e, 21e at the center of the first magnetic legs 20a, 21a. The outer peripheral surface of the first magnetic leg 20 a of the first core 20 is disposed in contact with the outer peripheral surface of the first magnetic leg 21 a of the second core 21.

  The primary spool 3 is a rectangular tube body having a rectangular tube portion and end walls extending in the diameter increasing direction from both axial end portions of the rectangular tube portion, and is made of, for example, an insulating material such as resin. . And it arrange | positions so that the outer peripheral surface of the 1st magnetic leg 20a of the 1st core 20 and the 1st magnetic leg 21a of the 2nd core 21 may be covered.

  Next, a specific operation will be described. An igniter (not shown) supplies a primary current to the primary coil 4 based on an ignition timing signal from an ECU (not shown). When the primary current flows, the primary coil 4 generates magnetic flux in the core 2. This magnetic flux flows separately into the first core 20 and the second core 21. While flowing from the first magnetic leg 20a of the first core 20 to the first magnetic leg 20a via the first magnetic joint portion 20c, the second magnetic leg 20b, and the second magnetic joint portion 20d, the first magnetic leg of the second core 21 is flown. By flowing from the leg 21a to the first magnetic leg 21a through the first magnetic coupling part 21c, the second magnetic leg 21b, and the second magnetic coupling part 21d, the secondary coil 6 is linked. For this reason, a high voltage is induced in the secondary coil 6. This high voltage is applied to the spark plug, which generates a spark in the gap between its electrodes.

  Finally, specific effects will be described. According to the third embodiment, in the ignition coil 1, the core 2 can be configured by two square-shaped first cores 20 and second cores 21 arranged adjacent to each other. Furthermore, the magnetic flux generated by the primary coil 4 can be divided and passed between the first core 20 and the second core 21. Therefore, the magnetic flux flowing through the first core 20 and the second core 21 is reduced, and the cross-sectional areas of the first core 20 and the second core 21 can be reduced. Thereby, the dimension of the lamination direction of the 1st core 20 and the 2nd core 21 can be made small, and the dimension of the up-down direction of the core 2 can be made small in FIG.

  In the above-described embodiment, the first core 20 and the second core 21 are disposed adjacent to each other on the same plane, but the present invention is not limited to this. The surface surrounded by the first core 20 and the surface surrounded by the second core 21 may be disposed adjacent to each other at a predetermined angle. Thereby, the shape of the core 2 can be freely changed according to the restrictions at the time of vehicle mounting.

(Fourth embodiment)
Next, FIG. 7 shows an axial sectional view of the ignition coil in the fourth embodiment, and FIG. 8 shows a perspective view of the core. Here, only the parts different from the ignition coil in the first, second and third embodiments will be described, and the description of the common parts will be omitted except for the necessary parts. In addition, the same code | symbol is attached | subjected and demonstrated to the element same as the said embodiment.

  First, a specific structure will be described with reference to FIGS. The core 2 is formed by laminating strip-shaped directional silicon steel plates that are long in the easy magnetization direction in the plate thickness direction with the easy magnetization direction aligned, and further bent along the easy magnetization direction and formed into a square shape. The first core portion 22 and the second core portion 23 are connected to each other. The first core portion 22 and the second core portion 23 are magnetically coupled between the first magnetic legs 22a and 23a, the second magnetic legs 22b and 23b, and the opposed shaft end portions, respectively. The first magnetic connection portions 22c and 23c and the second magnetic connection portions 22d and 23d are provided with gaps 22e and 23e on the second magnetic connection portions 22d and 23d side of the first magnetic legs 22a and 23a. The second magnetic connection portion 22d of the first core portion 22 and the second magnetic connection portion 23d of the second core portion 23 are integrally connected.

  Next, specific effects will be described. According to the fourth embodiment, the ignition coil 1 comprises the core 2 with two square-shaped first core portion 22 and second core portion 23 that are integrally connected and disposed adjacent to each other. can do. Furthermore, the magnetic flux generated by the primary coil 4 can be divided into the first core portion 22 and the second core portion 23 and flowed. Therefore, the first core part 22 and the second core part 23 are integrally connected, so that the number of parts can be reduced and the efficiency of the assembling work can be improved. Moreover, the magnetic flux which flows into the 1st core part 22 and the 2nd core part 23 becomes small, and the cross-sectional area of the 1st core part 22 and the 2nd core part 23 can be made small. Thereby, the dimension of the lamination direction of the 1st core part 22 and the 2nd core part 23 can be made small, and the dimension of the up-down direction of the core 2 can be made small in FIG.

  In the first to fourth embodiments described above, an example is given in which the gap is disposed at the center of the first magnetic leg or the second magnetic joint portion side, but is not limited thereto. The void may or may not be in any part of the core.

An axial direction sectional view of an ignition coil in a 1st embodiment is shown. The perspective view of the core in 1st Embodiment is shown. An axial direction sectional view of an ignition coil in a 2nd embodiment is shown. The perspective view of the core in 2nd Embodiment is shown. An axial direction sectional view of an ignition coil in a 3rd embodiment is shown. The perspective view of the core in 3rd Embodiment is shown. The axial direction sectional drawing of the ignition coil in 4th Embodiment is shown. The perspective view of the core in 4th Embodiment is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Ignition coil 2 ... Core 20 ... 1st core 21 ... 2nd core 22 ... 1st core part 23 ... 2nd core part 3 ... Primary spool 4- .. Primary coil 5 ... Secondary spool 6 ... Secondary coil 7 ... Resin

Claims (4)

A core that forms a magnetic path; a primary coil that is wound around the core and generates a magnetic flux by flowing current; and the core that is wound around the core and is generated by the primary coil In an ignition coil comprising a secondary coil that induces a voltage by magnetic flux flowing through
The ignition is characterized in that the core is formed by laminating magnetic plates having an easy magnetization direction with easy magnetization in the plate thickness direction so that the easy magnetization directions are aligned, and being bent along the easy magnetization direction. coil.   The ignition coil according to claim 1, wherein the core is rounded and bent.   3. The ignition according to claim 1, wherein the core includes a first U-shaped core and a second U-shaped second core disposed adjacent to the first core. 4. coil.   The core includes a first U-shaped core part, and a second U-shaped second core part that is integrally connected to the first core part and disposed adjacent to the first core part. The ignition coil according to claim 1 or 2, wherein

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