JP4683410B2 - Ignition coil for internal combustion engine - Google Patents

Description

  The present invention relates to an ignition coil for an internal combustion engine that supplies a high voltage for generating a spark discharge to an ignition plug of an internal combustion engine such as an automobile engine.

  FIG. 5 is a cross-sectional view showing a schematic configuration of an example of an ignition coil for an internal combustion engine.

In FIG. 5, reference numeral 1 denotes an ignition coil for an internal combustion engine, and includes an insulating case 11, an ignition coil portion 21 accommodated in the first accommodating recess 12 of the insulating case 11, and a second accommodating recess 14 of the insulating case 11. And a plurality of low-voltage terminals (primary terminals) 51 provided in the insulating case 11 and connected to the power transistor 41. The power transistor 41 is a power switch that controls power to the primary coil 26 of the ignition coil unit 21. A high-voltage terminal (secondary terminal) 52 that is attached to the high-voltage terminal attachment hole 13 provided in the bottom of the insulating case 11 that is the bottom of the first housing recess 12 and connected to the secondary coil 29 of the ignition coil portion 21; The resin is filled in the second housing recess 14 of the insulating case 11 and absorbs stress applied to the power transistor 41. For example, a buffer resin such as silicone or synthetic rubber 1, filled in the insulating case 11 excluding the second accommodating recess 14, and a thermosetting resin 62 as an insulating material to perform high-voltage isolation mutual each component.
The low voltage terminal 51 is inserted when the insulating case 11 is molded.

  In the insulating case 11 described above, the first accommodating recess 12 that accommodates the ignition coil portion 21 and the high-voltage terminal 52 that is located at the bottom of the first accommodating recess 12 and is attached by being press-fitted, for example. A mounting hole 13 and a second housing recess 14 for housing the power transistor 41 are provided.

Further, the ignition coil portion 21 is a rectangular parallelepiped center iron core 22a having a rectangular cross-sectional shape orthogonal to the longitudinal direction, and the center iron core 22a is disposed on the inner side so as to form a closed magnetic circuit together with the center iron core 22a. 29, an iron core 22 composed of an annular side iron core 22b, a rectangular cylindrical primary coil bobbin 23 through which the center iron core 22a is inserted, and a pair of terminals (not shown) provided at the ends of the primary coil bobbin 23. ), A primary coil 26 formed by winding and winding a winding 25 around the outer periphery of the primary coil bobbin 23, a square cylindrical secondary coil bobbin 27 disposed on the outer periphery of the primary coil 26, and the secondary coil bobbin Winding 28 is wound around the outer periphery of 27, and a secondary coil 29 formed by lamination and a secondary coil bobbin 27 are provided at one end of the secondary coil 29. A terminal 30A to which one end of the winding 28 forming the coil 29 is connected and a terminal (not shown) provided at the other end of the secondary coil bobbin 27 and connected to the other end of the winding 28 forming the secondary coil 29. ) And the other end of the secondary coil 29 (the other end of the winding 28 forming the secondary coil 29), and a terminal pin 31 that connects the secondary coil 29 and the high-voltage terminal 52. ing.
The primary and secondary coils 26 and 29, the power transistor 41, and the plurality of low voltage terminals 51 are connected so as to form a predetermined circuit.
Note that two terminals (first terminal and second terminal) provided on one of the flanges provided at both ends of the primary coil bobbin 23 are inserted when the primary coil bobbin 23 is molded or attached after the primary coil bobbin 23 is molded. It is done.
In addition, the terminal 30A (first terminal) provided on the secondary coil bobbin 27 and the terminal (second terminal) not shown are inserted into the flange portion integrally formed at both ends of the rectangular cylindrical portion at the time of molding. Or it is attached after the secondary coil bobbin 27 is formed.

  FIG. 6 is an enlarged perspective view showing a primary coil bobbin and an example of a primary coil in a conventional ignition coil for an internal combustion engine, with the other flange of the primary coil bobbin facing forward, and FIG. 7 is a cross-sectional view taken along line AA in FIG. It is explanatory drawing equivalent to a figure, and the same code | symbol is attached | subjected to FIG.

In these figures, the primary coil bobbin 23 is inserted with a center iron core, for example, a rectangular cylindrical portion 23a, and flanges 23b (one side) and 23c (one portion) formed integrally with both ends of the cylindrical portion 23. The other).
And the winding start end part (one end) of the coil | winding 25 which forms the primary coil 26 is connected and fixed to one collar part 23b, and the coil | winding which forms the primary coil 26 and the terminal (1st terminal) 24A to which it fixes. 25 is provided with a terminal (second terminal) 24B to which the winding end (other end) is connected and fixed, and one end is connected to the terminal 24A and the fixed winding 25 is connected to the outer periphery of the cylindrical portion 23a. A guide groove 23ba extending in the axial direction of the cylindrical portion 23a so as to guide, and a guide groove 23bb extending in the axial direction of the cylindrical portion 23a so as to guide the other end of the winding 25 forming the primary coil 26 to the terminal 24B. And are provided.

Next, formation of the primary coil 26 will be described.
First, after one end of the winding 25 is wound and connected and fixed to the terminal 24A, the winding 25 is guided from the induction groove 23ba to the outer periphery of the cylindrical portion 23a, and as shown in FIGS. The winding 25 is wound around the outer periphery of the cylindrical portion 23a and laminated to form the primary coil 26.
Then, the other end of the winding 25 forming the primary coil 26 is led from the induction groove 23bb to the terminal 24B, and the other end of the winding 25 is wound around the terminal 24B to be connected and fixed.
JP 2003-37016 A

In the conventional primary coil bobbin 23 in the internal combustion engine ignition coil 1, when the number of windings 25 forming the primary coil 26 is an even number, as shown in FIG. Since the 25 winding end portions are on the same side, the two terminals 24A and 24B can be provided on the flange portion 23b as shown in FIG.
However, when the number of windings 25 forming the primary coil 26 is an odd number, the winding start end of the winding 25 and the winding end end of the winding 25 are opposite to each other as shown in FIG. Therefore, it is necessary to provide the two terminals 24A and 24B separately in the flange portions 23b and 23c.
Therefore, it is necessary to prepare two primary coil bobbins in which the positions where the two terminals (24A, 24B) are provided are changed depending on the number of windings 25 forming the primary coil 26.
Further, since the primary coil bobbin 23 is formed in a square cylinder shape, if the winding 25 is wound around the primary coil bobbin 23, deformation stress is applied to the winding 25 due to the angular corner, and the winding 25 may be disconnected. .

  The present invention has been made to solve the above-described disadvantages, and the winding end end portion of the winding is not limited regardless of the number of windings (odd number, even number) of the windings forming the primary coil or the secondary coil. An ignition coil for an internal combustion engine that can be an arbitrary flange portion of a primary coil bobbin or a secondary coil bobbin and can prevent a winding from being disconnected.

The present invention is as follows.
(1) An internal combustion in which a primary coil formed by winding a winding around the outer periphery of a primary coil bobbin and a secondary coil disposed outside the primary coil are magnetically coupled by a center iron core disposed in the primary coil bobbin. In the engine ignition coil, the winding start end portion of the winding is connected to the first terminal on the other flange side facing the one flange portion of the primary coil bobbin provided with the first terminal to be connected and fixed. , To change the direction by hooking the winding that is fixedly pulled out, and to provide a hook portion for winding around the outer periphery of the primary coil bobbin, the center core has a cross-sectional shape perpendicular to the longitudinal direction at the four corners of the rectangle The primary coil bobbin is a square tube, and a guide recess for guiding the winding from the first terminal to the hook is provided in the center. It is provided at a corner corresponding to one recess of the iron core, the remaining corner of the primary coil bobbin is a cylindrical surface, and the winding guided by the induction recess does not act as a protrusion so that it is wound around the outer periphery of the primary coil bobbin The primary coil is formed without deformation stress acting on the first layer of the winding .
(2) The ignition coil for an internal combustion engine according to (1), wherein the center iron core is insert-molded on the primary coil bobbin.

According to this invention, the winding start end of the winding is connected and fixed to the first terminal on the other flange side facing the one flange of the primary coil bobbin provided with the first terminal to be connected and fixed. Since the hook is pulled to change the direction and the hook is provided around the outer circumference of the primary coil bobbin, the number of windings (odd number, even number) can be reduced by not using or using the hook part. Regardless of (), the winding end portion of the winding forming the primary coil can be an arbitrary flange of the primary coil bobbin.
Therefore, the primary coil is formed on the outer periphery of the primary coil bobbin regardless of the number of windings (odd number, even number) regardless of how the first terminal and the second terminal are provided on the flanges at both ends of the primary coil bobbin. Can do.
The primary coil bobbin is provided with a guide recess for guiding the winding from the first terminal to the hook, and the center iron core is provided with a recess corresponding to the guide recess, so that it is further orthogonal to the longitudinal direction of the center core. The cross-sectional shape is a shape in which a recess is provided in one of the four corners of a rectangle, the primary coil bobbin is a square tube, and a guide recess is provided in a corner corresponding to the recess in the center iron core. The first layer that forms the primary coil because the winding that is guided by the induction recess does not act as a protrusion on the first layer winding that forms the primary coil. Deformation stress does not act on the winding of the eye, and disconnection of the winding can be prevented.
In addition, the remaining corners of the cross-sectional shape of the center iron core are also provided with recesses, and the remaining corners of the primary coil bobbin have a cylindrical surface, so that further deformation stress does not act on the windings, further preventing breakage of the windings. In addition, by ensuring the thickness of the four corners of the primary coil bobbin, the thickness of the primary coil bobbin can be reduced, so that the size and weight can be reduced.
And since the center iron core is insert-molded into the primary coil bobbin or the secondary coil bobbin, the thickness can be reduced while ensuring the strength of the primary coil bobbin or the secondary coil bobbin, so that the size and weight can be reduced.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is an enlarged perspective view of a primary coil bobbin and a primary coil in an ignition coil for an internal combustion engine according to an embodiment of the present invention, with the other flange portion of the primary coil bobbin facing forward, and FIG. 2 is an embodiment of the present invention. FIG. 3 is an enlarged perspective view of a primary coil bobbin and a primary coil in an ignition coil for an internal combustion engine as an example, with one flange of the primary coil bobbin being on the near side, FIG. 3 is a cross-sectional view taken along line BB of FIG. FIG. 8 is an explanatory view corresponding to a cross-sectional view taken along the line CC of FIG. 1, and the same reference numerals are given to the same or corresponding parts as in FIGS.

In these figures, the center iron core 22a has a cross-sectional shape perpendicular to the longitudinal direction by laminating silicon steel plates, and has a shape provided with steps 22aa as concave portions at four corners of a rectangle (square).
Then, one end of the primary coil bobbin 23 is connected to a terminal (first terminal) 24A at a portion of the flange portion 23c, and the direction is changed by hooking the winding 25 that is pulled out and fixed to the outer periphery of the cylindrical portion 23a. A hooking column 23ca as a hooking part used for winding is provided corresponding to the terminal 24A, and the coil 25 from the terminal 24A is guided to the hooking column 23ca at the corner of the cylindrical part 23a connected to the guiding groove 23ba. The guide recess 23aa is provided, and the other corner of the cylindrical portion 23a is a cylindrical surface.
The center iron core 22 a is inserted when the primary coil bobbin 23 is formed, and is disposed in the primary coil bobbin 23.

Next, formation of the primary coil 26 will be described.
First, the case where the number of windings 25 is an odd number will be described. After one end of the winding 25 is wound around the terminal 24A to be connected and fixed, as shown in FIG. 2, the winding 25 is guided from the guide groove 23ba to the guide recess. It guide | induces to 23aa, it guide | induces from the guide recessed part 23aa to the hook support | pillar 23ca, and is wound around the hook support | pillar 23ca about a half circumference.
As shown in FIGS. 1 and 4, after the winding 25 is hooked around the supporting column 23 ca and the direction is changed so that the winding 25 is returned to the outer periphery of the cylindrical portion 23, from the flange portion 23 c side, as shown in FIGS. 1 and 4. Next, the winding 25 is wound around the outer periphery of the cylindrical portion 23a and laminated to form the primary coil 26.
Then, the other end of the winding 25 forming the primary coil 26 is led from the induction groove 23bb to the terminal (second terminal) 24B, and the other end of the winding 25 is wound around the terminal 24B to be connected and fixed.

Next, the case where the number of the windings 25 is an even number will be described. After winding one end of the winding 25 around the terminal 24A to be connected and fixed, the winding 25 is guided from the induction groove 23ba to the outer periphery of the cylindrical portion 23a. The primary coil 26 is formed by winding and winding the winding 25 around the outer periphery of the tubular portion 23a from the flange portion 23a side.
Then, the other end of the winding 25 forming the primary coil 26 is led from the induction groove 23bb to the terminal 24B, and the other end of the winding 25 is wound around the terminal 24B to be connected and fixed.

As described above, according to one embodiment of the present invention, the two terminals 24A for connecting and fixing the both ends of the winding 25 forming the primary coil 26 to the flange 23b provided at the end of the primary coil bobbin 23, 24B is provided, and on the side of the flange portion 23c, a hooking strut 23ca for hooking the winding 25 connected to the terminal 24A, fixing and pulling is changed, and wound around the outer periphery of the primary coil bobbin 23 (tubular portion 23a). Since the hook support column 23ca is not used or used, the winding start end portion and the winding of the winding 25 forming the primary coil 26 are used regardless of the number of windings 25 stacked (odd number, even number). The same winding part 23b of the primary coil bobbin 23 can be used as the end of the 25 winding ends.
Therefore, even if the two terminals 24A and 24B are provided on the flange 23b of the primary coil bobbin 23, the primary coil 26 can be formed on the outer periphery of the primary coil bobbin 23 regardless of the number of windings 25 (odd number, even number). it can.
The primary coil bobbin 23 (cylindrical portion 23a) is provided with a guide recess 23aa for hooking the winding 25 from the terminal 24A and guiding it to the support column 23ca, and the center iron core 22a is provided with a step 22aa corresponding to the guide recess 23aa. Therefore, by winding and guiding the winding 25 from the terminal 24A to the hooking column 23ca in the induction recess 23ca, the winding 25 that is guided by the induction recess 23ca to the first layer winding 25 that forms the primary coil 26 is formed. Deformation stress does not act on the first-layer winding 25 that does not act as a protrusion and forms the primary coil 26, and disconnection of the winding 25 can be prevented.
Further, since the step 22aa is provided at the remaining corner of the cross-sectional shape of the center iron core 22a and the remaining corner of the primary coil bobbin 23 (cylindrical portion 23a) is a cylindrical surface, no further deformation stress acts on the winding 25. The wire 25 can be further prevented from being disconnected, and the primary coil bobbin 23 can be made thinner by securing the thickness of the four corners of the primary coil bobbin 23 (tubular portion 23a). A reduction in size and weight can be achieved.
And since the center iron core 22a was insert-molded in the primary coil bobbin 23, thickness can be made thin, ensuring the intensity | strength of the primary coil bobbin 23, and size reduction and weight reduction can be achieved.
Further, since the center iron core 22a is formed by laminating silicon steel plates, the steps 22aa can be easily provided at the four corners.

In the above-described embodiment, the center iron core 22a is configured by laminating silicon steel plates, and the cross-sectional shape orthogonal to the longitudinal direction is rectangular. However, if it can be configured in the same shape, It may be configured.
And although the example which provided both terminal 24A, 24B in the collar part 23b demonstrated the primary coil 26 irrespective of the lamination | stacking number (odd number, even number) of the coil | winding 25 even if the terminal 24B was provided in the collar part 23c. It can be formed on the outer periphery of the primary coil bobbin 23 .

FIG. 3 is an enlarged perspective view of the primary coil bobbin and the primary coil in the ignition coil for an internal combustion engine that is one embodiment of the present invention, with the other flange portion of the primary coil bobbin facing forward. 1 is an enlarged perspective view of a primary coil bobbin and a primary coil in an ignition coil for an internal combustion engine according to an embodiment of the present invention, with one flange portion of the primary coil bobbin facing forward. It is sectional drawing by the BB line of FIG. It is explanatory drawing equivalent to sectional drawing by CC line of FIG. It is sectional drawing which shows schematic structure of an example of the ignition coil for internal combustion engines. It is an expansion perspective view of the state which made the other collar part of the primary coil bobbin which shows an example of the primary coil bobbin and the primary coil in the conventional internal combustion engine ignition coil the front side. It is explanatory drawing corresponded in sectional drawing by the AA line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ignition coil for internal combustion engines 11 Insulating case 12 1st accommodation recessed part 13 High voltage terminal attachment hole 14 2nd accommodation recessed part 21 Ignition coil part 22 Iron core 22a Center iron core 22aa Level difference (recessed part)
22b Side iron core 23 Primary coil bobbin 23a Tubular part 23aa Guide recess 23b Ridge part 23ba Guide groove 23bb Guide groove 23c Ridge part 23ca Winding support (hanging part)
24A terminal (first terminal)
24B terminal (second terminal)
25 Winding 26 Primary coil 27 Secondary coil bobbin 28 Winding 29 Secondary coil 30A Terminal (first terminal)
31 terminal pin 41 power transistor (power switch)
51 Low voltage terminal (primary terminal)
52 High voltage terminal (secondary terminal)
61 Buffering resin 62 Thermosetting resin (insulating material)

Claims (2)

Ignition for an internal combustion engine in which a primary coil formed by winding a winding around the outer periphery of a primary coil bobbin and a secondary coil arranged outside the primary coil are magnetically coupled by a center iron core arranged in the primary coil bobbin In the coil
The winding start end of the winding is connected and fixed to the first terminal on the other side of the primary coil bobbin provided with the first terminal to which the first terminal is connected and fixed. Hook the winding to change the direction, and provide a hook for winding the outer periphery of the primary coil bobbin,
The center iron core has a cross-sectional shape perpendicular to the longitudinal direction, and a shape having steps as concave portions at four corners of a rectangle.
The primary coil bobbin is a square tube, and a guide recess for guiding the winding from the first terminal to the hook is provided at a corner corresponding to one recess of the center iron core, and the remaining primary coil bobbin Make the corner cylindrical,
The primary coil is formed without any deformation stress acting on the first-layer winding wound around the outer periphery of the primary coil bobbin because the winding induced by the induction recess does not act as a protrusion. An ignition coil for an internal combustion engine. The ignition coil for an internal combustion engine according to claim 1,
The center iron core is insert-molded into the primary coil bobbin.
An ignition coil for an internal combustion engine.

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