JP6424689B2 - Ignition coil for internal combustion engine - Google Patents

Description

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

  As an ignition coil for an internal combustion engine, a primary coil and a secondary coil magnetically coupled to each other, a central core disposed inside the primary coil and the secondary coil, and an outer periphery of the primary coil and the secondary coil And an outer peripheral core.

  Patent Document 1 discloses an ignition coil provided with an igniter for energizing and interrupting the primary coil. Further, in the ignition coil described in Patent Document 1, the igniter is disposed opposite to the outer peripheral surface of the outer peripheral core so as to efficiently dissipate the heat of the igniter to the outer peripheral core. In addition, the igniter is disposed at a position overlapping the central core in the axial direction in the axial direction from the viewpoint of ease of connection to the primary coil and the like.

Patent No. 4978497 gazette

  However, since the central core, a part of the outer peripheral core, and the igniter are arranged in the axial direction, there is a problem that the ignition coil tends to be enlarged in the axial direction. From the viewpoint of the mountability of the ignition coil to the engine, etc., it is desirable that the ignition coil be reduced in axial dimension.

  Therefore, it is conceivable to dispose the igniter at a position not facing the outer peripheral surface of the outer peripheral core or at a position not overlapping the central core in the axial direction. However, the heat dissipation of the igniter, connectivity between the igniter and the primary coil, etc. There is a problem from

  The present invention has been made in view of such background, and an object of the present invention is to provide an ignition coil for an internal combustion engine which can realize downsizing in the winding axial direction and improvement of the heat dissipation of the igniter. is there.

One aspect of the present invention relates to a primary coil and a secondary coil magnetically coupled to each other;
A central core disposed on the inner circumferential side of the primary coil and the secondary coil;
An outer peripheral core disposed outside the primary coil and the secondary coil to form a magnetic circuit with the central core;
And an igniter for energizing and interrupting the primary coil.
The outer peripheral core has a pair of opposing parts respectively facing the both end faces of the central core in the winding axis direction,
One of the pair of facing parts has a notch that opens outward,
At least a portion of the igniter is an ignition coil for an internal combustion engine, which is disposed in the notch.

  In the ignition coil for the internal combustion engine, at least a portion of the igniter is disposed in the notch. Therefore, since the igniter is disposed at the notch, the miniaturization of the ignition coil in the winding axial direction can be realized.

  Moreover, since the notch part of an outer periphery core will be arrange | positioned around an igniter, the heat transfer distance from an igniter to an outer periphery core can be shortened, and the improvement of heat dissipation can also be implement | achieved.

  As described above, according to the present invention, it is possible to provide an ignition coil for an internal combustion engine that can realize downsizing in the winding axial direction and improvement of the heat dissipation of the igniter.

1 is a partial cross-sectional side view of an ignition coil for an internal combustion engine in Embodiment 1. FIG. FIG. 2 is a cross-sectional view of the ignition coil for an internal combustion engine according to the first embodiment, taken along a cross section passing through a notch. 5 is a perspective view of a central core, an outer peripheral core, and an igniter in Embodiment 1. FIG. FIG. 2 is a top view of a central core, an outer peripheral core, and an igniter in Embodiment 1. 3 is a perspective view of a central core and an outer peripheral core in Embodiment 1. FIG. The top view of a central core, a magnet, a perimeter core, and an igniter in Example 2. FIG. FIG. 10 is a cross-sectional view of a spark coil for an internal combustion engine according to a second embodiment, with a cross section passing through a notch. FIG. 18 is a perspective view of a central core, an outer peripheral core, and an igniter in Embodiment 3. The top view of a central core, an outer periphery core, and an igniter in Example 3. FIG. FIG. 16 is a perspective view of a central core and an outer peripheral core in a third embodiment. FIG. 18 is a perspective view of a central core, an outer peripheral core, and an igniter in a fourth embodiment. The top view of a central core, an outer periphery core, and an igniter in Example 4. FIG.

The ignition coil for an internal combustion engine can be used, for example, in an internal combustion engine such as a car or a cogeneration.
Moreover, in the present specification, the winding axis direction of the primary coil and the secondary coil may be simply referred to as the axial direction.

Example 1
An embodiment of an ignition coil for an internal combustion engine will be described using FIGS. 1 to 5.
The ignition coil 1 for an internal combustion engine of this embodiment, as shown in FIGS. 2 to 4, includes a primary coil 21 and a secondary coil 22 magnetically coupled to each other, a central core 3, an outer peripheral core 4 and an igniter 5. Have. As shown in FIG. 2, the central core 3 is disposed on the inner peripheral side of the primary coil 21 and the secondary coil 22. The outer peripheral core 4 is disposed outside the primary coil 21 and the secondary coil 22 to form a magnetic circuit with the central core 3. The igniter 5 energizes the primary coil 21 and shuts it off.
As shown in FIG. 2 and FIG. 4, the outer peripheral core 4 has a pair of opposing parts 41 and 42 which respectively oppose the both end faces 31 and 32 of the central core 3 in the axial direction X. As shown in FIGS. 2 to 5, one of the pair of facing portions 41 and 42 has a notch 43 opened outward. As shown in FIGS. 1 to 4, at least a part of the igniter 5 is disposed in the notch 43.

  As shown in FIG. 2, the primary coil 21 and the secondary coil 22 are concentrically arranged on the inner and outer circumferences. The primary coil 21 is wound around the central core 3, and the secondary coil 22 is wound around a bobbin 11 disposed on the outer peripheral side of the primary coil 21.

  As shown in FIGS. 1, 3 and 5, the central core 3 and the outer peripheral core 4 are in the direction orthogonal to the axial direction X of the flat electromagnetic steel plate 100 made of soft magnetic material, and the thickness direction of the electromagnetic steel plate 100 A plurality of layers are stacked. In the following, the stacking direction of the plurality of electromagnetic steel plates 100 in the central core 3 and the outer peripheral core 4 is referred to as the stacking direction Z, and a direction orthogonal to both the axial direction X and the stacking direction Z is referred to as the lateral direction Y.

  The end face 31 of the central core 3 opposed to the facing portion 41 on the side where the igniter 5 is disposed is a cross section orthogonal to the axial direction X of the portion of the central core 3 disposed inside the primary coil 21 and the secondary coil 22 The area is larger than that. That is, as shown in FIGS. 3 to 5, the central core 3 has, on the side of the facing portion 41, the core protruding portion 302 which is wider in the lateral direction Y than the other portions. Specifically, the central core 3 has a core main body portion 301 having a substantially rectangular parallelepiped shape, and a core projection portion 302 projecting on both sides in the lateral direction Y than the core main body portion 301 at the end on the side where the igniter 5 is disposed. It consists of As shown in FIG. 2, the primary coil 21 is wound around the core main body 301. As shown in FIG. 4, the end face 31 of the central core 3 is formed to project on both sides in the lateral direction Y more than the notch 43. In other words, in the lateral direction Y, the notch 43 is located inside the end face 31 of the central core 3.

  As shown in FIGS. 3 to 5, the outer peripheral core 4 is disposed so as to surround the central core 3 from both sides in the axial direction X and from both sides in the lateral direction Y. That is, the outer peripheral core 4 is a substantially rectangular frame in which both sides in the stacking direction Z are open, and two sides extend in the lateral direction Y and the other two sides extend in the axial direction X. As shown in FIG. 2 and FIG. 4, two sides of the outer peripheral core 4 extending in the lateral direction Y have opposing portions 41 and 42 that respectively oppose the end faces 31 and 32 of the central core 3 in the axial direction X. In FIG. 1, illustration of two sides of the outer peripheral core 4 extending in the axial direction X is omitted.

  As shown in FIGS. 3 to 5, a notch 43 is formed in one of the pair of facing portions 41 and 42 (facing portion 41) of the outer peripheral core 4. As shown in FIG. 4, in the outer peripheral core 4, a notch 43 is formed in the facing portion 41 facing the end surface 31 of the central core 3 on the core protruding portion 302 side in the axial direction X. As shown in FIGS. 3 to 5, in the present example, the notch 43 has a concave shape that is recessed inward from the outer side surface of the facing portion 41. That is, in the present example, the notch 43 opens outward, but does not open inward. The cutout portion 43 is formed over the entire region in the stacking direction Z at the facing portion 41.

  As shown in FIGS. 2 to 4, the igniter 5 is disposed in the notch 43 so that at least a part thereof faces the inner wall surface of the notch 43 in the facing portion 41. In the present example, the igniter 5 has a substantially rectangular parallelepiped shape, and the pair of main surfaces facing the axial direction X has a shape wider than the other end surfaces. Then, in the igniter 5, one main surface and a part of the pair of end surfaces in the lateral direction Y are opposed to the inner wall surface of the notch 43. The igniter 5 partially overlaps the outer peripheral core 4 in the lateral direction Y. That is, as shown in FIG. 1, when viewed in the lateral direction Y, a part of the igniter 5 is accommodated inside the outer peripheral core 4.

  As shown in FIGS. 1 to 3, the igniter 5 has a terminal portion 52 projecting in the stacking direction Z from a main portion 51 formed by resin molding a switching control circuit or the like that performs energization to the primary coil 21 and interrupting energization. .

  As shown in FIGS. 2 to 4, the central core 3, the facing portions 41 and 42 of the outer peripheral core 4, and the igniter 5 are arranged side by side in the axial direction X. As shown in FIGS. 2 and 4, a gap 6 is formed between the facing portion 41 on the side where the igniter 5 is disposed and the end surface 31 of the central core 3.

  As shown in FIGS. 1 and 2, the primary coil 21 and the secondary coil 22, the central core 3, the outer peripheral core 4, and the igniter 5 are housed in a case 12 having insulation. In the case 12, a cylindrical high-pressure tower portion 14 into which the high-pressure output terminal 13 is inserted is formed to protrude. The side of the secondary coil 22 opposite to the primary coil 21 is electrically connected to a spark plug (not shown) via the high voltage output terminal 13 or the like. A region of the case 12 opposite to the projecting side of the high pressure tower portion 14 with respect to the high voltage output terminal 13 is filled with a filling resin 15 having an insulating property. The case 12 also has a connector portion 16 for electrically connecting the ignition coil 1 to an external device. The connector portion 16 is provided with a control signal transmission terminal 17 for electrically connecting to an external control device for controlling on / off of the switching element in the igniter 5. The terminal portion 52 of the igniter 5 is connected. In FIG. 1, illustration of the filling resin is omitted. Moreover, in FIG.4, FIG.6, FIG.9 and FIG. 12, illustration of the terminal part of an igniter is abbreviate | omitted.

Next, the operation and effect of this embodiment will be described.
In the ignition coil 1 for an internal combustion engine, at least a portion of the igniter 5 is disposed in the notch 43. Therefore, as the igniter 5 is disposed in the notch 43, the miniaturization of the ignition coil 1 in the axial direction X can be realized.

  Further, since the notch 43 of the outer peripheral core 4 is disposed around the igniter 5, the heat transfer distance from the igniter 5 to the outer peripheral core 4 can be shortened, and the improvement of the heat dissipation can be realized. Can.

  In addition, the notch 43 has a concave shape that is recessed inward from the outer side surface of the facing portion 41. That is, the cutaway portion 43 is not open to the central core 3 side, and a part of the facing portion 41 is formed on the central core 3 side of the cutaway portion 43. Therefore, the cross-sectional area of the facing portion 41 can be increased, and the magnetic performance can be improved.

  Further, a gap 6 is formed between the facing portion 41 on the side where the igniter 5 is disposed and the end surface 31 of the central core 3. As a result, a leakage flux is generated outside the gap 6. Therefore, by forming the gap 6, the magnetic flux density formed in the facing portion 41 is reduced. For example, the magnetic flux density formed in the facing portion 41 is approximately half of the maximum magnetic flux density. As a result, even if the notches 43 are formed in the facing portion 41, it is possible to suppress the decrease in the magnetic performance.

  Further, the end face 31 of the central core 3 opposed to the opposing portion 41 on the side where the igniter 5 is disposed is orthogonal to the axial direction X of the portion of the central core 3 disposed inside the primary coil 21 and the secondary coil 22. The area is larger than the cross section. Here, magnetic flux is formed in the central core 3 and the outer peripheral core 4 so as to pass the shortest path magnetically. Therefore, the end face 31 of the central core 3 may be formed with a portion where the density of the formed magnetic flux increases and a portion where the magnetic flux density decreases. For example, in the present embodiment, the magnetic flux is likely to be concentrated at both end portions in the lateral direction Y at the end face 31 of the central core 3 while the magnetic flux is unlikely to be concentrated at the central portion. Therefore, by increasing the end face 31 of the central core 3 in the lateral direction Y, it is possible to form a location where the magnetic flux density in the end face 31 of the central core 3 is higher on the outer side in the lateral direction Y. Along with this, it is possible to increase the area where the magnetic flux density is low in the central portion of the facing portion 41 in the lateral direction Y. Then, by setting the position where the notch portion 43 is formed to be the above region in the facing portion 41, it is possible to suppress the decrease in the magnetic performance.

  As described above, according to the present embodiment, it is possible to provide an ignition coil for an internal combustion engine that can realize downsizing in the axial direction and improvement of the heat dissipation of the igniter.

(Example 2)
In this example, as shown in FIGS. 6 and 7, an example in which the magnet body 7 is disposed in the gap 6 formed between the facing portion 41 on the side where the igniter 5 is disposed and the end face 31 of the central core 3 It is. As shown in FIG. 6, the magnet body 7 protrudes to both sides in the lateral direction Y more than the notch 43. The magnet body 7 is disposed such that the direction of the magnetic field generated from the magnet body 7 is opposite to the direction of the magnetic field generated in the central core 3 when current flows through the primary coil 21. In order to improve the output voltage of the ignition coil 1, the magnet body 7 applies a magnetic bias to the central core 3 to increase the amount of change in magnetic flux at the time of interruption of the energization to the primary coil 21 to be induced in the secondary coil 22. Voltage is increasing.

  Others are the same as in the first embodiment. Among the reference numerals used in the present example or the drawings relating to the present example, the same reference numerals as those used in the first example represent the same constituent elements as those of the first example unless otherwise indicated.

In the present embodiment, the magnetic flux formed by the energization of the primary coil 21 is influenced by the magnetic bias formed by the magnet body 7, so that the leakage magnetic flux is likely to be generated outside the gap 6. Therefore, the magnetic flux density generated in the facing portion 41 (notch portion 43) on the side adjacent to the gap 6 is further reduced by arranging the magnet body 7 protruding on both sides in the lateral direction Y from the cutout portion 43 in the gap 6. . As a result, even if the notches 43 are formed in the facing portion 41, it is possible to further suppress the decrease in magnetic performance.
In addition, the same effect as that of the first embodiment is obtained.

(Example 3)
In this example, as shown in FIGS. 8 to 10, the notch 43 is open toward the outside and is also open toward the inside. That is, the cutaway portion 43 is formed to penetrate in the axial direction X the opposing portion 41 on the side where the igniter 5 is disposed. Also in this example, the notch 43 is formed to be located inside the central core 3 in the lateral direction Y.

  As shown in FIGS. 8 and 9, in the igniter 5, both end surfaces in the lateral direction Y are opposed to the inner wall surface of the notch 43. Then, as shown in FIG. 9, one main surface of the igniter 5 is opposed to the end surface 31 of the central core 3. In this example, when viewed in the lateral direction Y, the entire igniter 5 is located inside the outer peripheral surface of the outer peripheral core 4.

  Others are the same as in the first embodiment. Among the reference numerals used in the present example or the drawings relating to the present example, the same reference numerals as those used in the first example represent the same constituent elements as those of the first example unless otherwise indicated.

In the present embodiment, since the igniter 5 can be disposed inside the outer peripheral surface of the outer peripheral core 4, the miniaturization of the ignition coil 1 in the axial direction X can be further achieved. Further, the heat of the igniter 5 can be dissipated to the outer peripheral core 4.
In addition, the same effect as that of the first embodiment is obtained.

(Example 4)
This example is an example in which the outer peripheral core 4 is modified with respect to the first embodiment as shown in FIGS. 11 and 12. The outer peripheral core 4 is disposed so as to cover the central core 3 from both sides in the axial direction X and one in the lateral direction Y. As shown in FIG. 12, the outer peripheral core 4 has a substantially U shape when viewed in the stacking direction Z. The outer peripheral core 4 is formed such that two sides extend in the lateral direction Y and the other side extends in the axial direction X. Two sides of the outer peripheral core 4 extending in the lateral direction Y respectively have facing portions 41, 42 facing the both end faces 31, 32 of the central core 3 in the axial direction X.

Others are the same as in the first embodiment. Among the reference numerals used in the present example or the drawings relating to the present example, the same reference numerals as those used in the first example represent the same constituent elements as those of the first example unless otherwise indicated.
Also in this example, the same effect as that of the first embodiment is obtained.

  The present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the present invention. For example, it is possible to combine Example 2 with Example 3 or Example 4, and the like. For example, the magnet body is disposed in the gap between the igniter and the central core in the third embodiment, and the end face on the central core side of the igniter is disposed opposite to the magnet body to heat the igniter It is also possible to dissipate heat to the central core via Also, for example, the central core and the outer peripheral core can be configured by compacting a soft magnetic material.

DESCRIPTION OF SYMBOLS 1 Ignition coil for internal combustion engines 21 Primary coil 22 Secondary coil 3 Center core 31, 32 End face of center core 4 Outer peripheral core 41, 42 Pair of opposing parts 43 Notch part 5 Igniter

Claims (5)

A primary coil (21) and a secondary coil (22) magnetically coupled to each other;
A central core (3) disposed on the inner peripheral side of the primary coil (21) and the secondary coil (22);
An outer peripheral core (4) disposed outside the primary coil (21) and the secondary coil (22) and forming a magnetic circuit with the central core (3);
An igniter (5) for energizing the primary coil (21) and interrupting the energization of the primary coil (21);
The outer peripheral core (4) has a pair of opposing parts (41, 42) that respectively oppose the both end faces (31, 32) of the central core (3) in the winding axial direction (X),
One of the pair of facing portions (41, 42) has a notch (43) opened to the outside,
An ignition coil (1) for an internal combustion engine, wherein at least a portion of the igniter (5) is disposed in the notch (43).   The ignition coil (1) for an internal combustion engine according to claim 1, wherein the notch (43) has a concave shape which is recessed inward from the outer surface of the opposing portion (41).   A gap (6) is formed between the facing portion (41) on the side where the igniter (5) is disposed and the end face (31) of the central core (3). An ignition coil (1) for an internal combustion engine according to claim 1 or 2.   An ignition coil (1) for an internal combustion engine according to claim 3, characterized in that a magnet (7) is arranged in the gap (6).   The end face (31) of the central core (3) facing the facing portion (41) on the side where the igniter (5) is disposed is the primary coil (21) and the two of the central core (3). 5. The internal combustion engine according to any one of claims 1 to 4, characterized in that the area is larger than the cross section orthogonal to the winding axis direction (X) of the portion disposed inside the next coil (22). Ignition coil (1).

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