JP3031158U - Ignition coil for internal combustion engine - Google Patents

Abstract

(57) Abstract: An ignition coil for an internal combustion engine, which is small and which can obtain high spark energy. SOLUTION: A secondary coil 5 is concentrically arranged on the outer peripheral side of a primary coil 3, and a coil body 1 integrally molded with an insulating member 9 and a closed magnetic circuit core 10 made of magnetic metal.
1 and the coil main body 1 has a closed magnetic circuit core 10 or 11
A permanent magnet 12 at a position of the closed magnetic circuit cores 10 and 11 different from the place where the coil body 1 is provided, and the permanent magnet 12 is magnetically arranged in series with the closed magnetic circuit. The area of the surface facing the magnetic path is set to 1.4 to 2 times the sectional area of the closed magnetic circuit core.

Description

[Detailed description of the device]

[0001]

[Technical field to which the device belongs]

 The present invention relates to a mold type internal combustion engine ignition coil for supplying a high voltage to generate a spark discharge in a spark plug of an automobile engine, and more particularly to an internal combustion engine ignition coil that is required to be downsized. is there.

[0002]

[Prior art]

 2. Description of the Related Art Conventionally, a molded type ignition coil for an internal combustion engine having a permanent magnet in a magnetic circuit has a schematic configuration, for example, as shown in a sectional view of FIG.

In FIG. 1, reference numeral 1 denotes an ignition coil body, which is a U-shaped silicon steel sheet laminated iron core 10, 11 having end portions facing each other and joined together to form a magnetic circuit forming a closed magnetic circuit. Configure.

In the magnetic circuit in the ignition coil body 1, a plate-shaped permanent magnet 12 for magnetic reverse bias is arranged so as to be sandwiched between the iron cores 10 and 11, and is described later by using an adhesive. The secondary coil bobbin is adhered and fixed to the primary coil bobbin.

Further, one joint portion 11a of the iron cores 10 and 11 is joined by welding or the like (hereinafter, a permanent magnet disposed at this position is referred to as an inner magnet type).

Reference numeral 2 denotes a primary coil bobbin integrally formed of an electrically insulating material such as synthetic resin, and the primary coil bobbin 2 is disposed in close contact with the outer periphery of the iron core and has a primary coil on the outer peripheral portion. The coil 3 is wound.

A secondary coil bobbin 4 is arranged concentrically on the outer periphery of the primary coil 3 and is made of an electrically insulating material such as synthetic resin. Multiple collars that function as partitions for split winding are integrally molded. The secondary coil 5 is wound around the secondary coil bobbin 4, for example, with the primary coil 3 having a winding ratio of about 1: 100 by partition winding with each collar portion as a partition.

Further, reference numeral 6 denotes an insulating case which is disposed further on the outer periphery of the secondary coil 5 and is made of an insulating member such as synthetic resin. At one end of the insulating case 6, the primary terminal 7 is provided. The high-voltage terminal 8 is provided on the bottom of the insulating case 6. After the insulating case 9 is filled with an insulating member 9 such as epoxy resin, the insulating member 9 is cured and fixed in a state where the members arranged inside the insulating case 6 are insulated. ing.

Further, the primary coil 3 and the primary terminal 7 and the secondary coil 5 and the high voltage terminal 8 are electrically connected to each other, and when a predetermined current is applied to the primary coil 3 and then cut off, a secondary coil 5 is connected. The generated high-voltage current is supplied from the high-voltage terminal 8 to the spark plug via a high tension cord (not shown).

The internal magnet type ignition coil for an internal combustion engine (so-called mold coil) configured as described above uses the permanent magnet 12 to apply a magnetic reverse bias to the iron cores 10 and 11 to cut off the primary coil current. The amount of change in the magnetic flux in the iron cores 10 and 11 at that time was increased to reduce the size and output of the molded coil.

[0011]

[Problems to be solved by the device]

 However, since the price of the above-mentioned permanent magnet is high, the price of the mold coil itself is also high.

The present invention solves such a drawback and relates to miniaturization and high output of an ignition coil for an internal combustion engine using a permanent magnet.

[0013]

The present invention has been made in view of the above, and a coil body in which a secondary coil is concentrically arranged on the outer peripheral side of a primary coil and integrally molded with an insulating member. And a closed magnetic circuit core made of magnetic metal, the ignition coil for an internal combustion engine having the coil body inserted into the closed magnetic circuit core, and the place where the coil body is disposed. Permanent magnets are magnetically arranged in series with the closed magnetic circuit at different positions of the closed magnetic circuit core, and the area of the surface of the permanent magnet facing the magnetic path is 1. It is intended to provide an ignition coil for an internal combustion engine which has a quadruple to double fold.

The present invention also provides an ignition coil for an internal combustion engine, wherein the thickness of the permanent magnet is a value obtained by multiplying the area of the permanent magnet by 0.007 to 0.01.

Further, the present invention provides an ignition coil for an internal combustion engine, wherein the magnetic metal forming the closed magnetic circuit core is a laminated body of grain-oriented silicon steel plates.

According to the present invention, the secondary coil is concentrically arranged on the outer peripheral side of the primary coil, and is composed of a coil body integrally molded with an insulating member and a closed magnetic circuit iron core made of magnetic metal. An ignition coil for an internal combustion engine in which the coil body is inserted into the closed magnetic circuit core and is magnetically saturated in series in series with a permanent magnet disposed in a part of the magnetic path of the closed magnetic circuit core. An ignition coil for an internal combustion engine provided with a gap for prevention or a spacer made of a non-magnetic material.

[0017]

[Embodiment of device]

 The present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view of an internal combustion engine ignition coil according to an embodiment of the present invention. The same members as those in the conventional example are designated by the same reference numerals.

The greatest feature of this embodiment is that the permanent magnet 12 is provided not inside the ignition coil body 1 but on the side facing one side of the closed magnetic circuit cores 10 and 11 in which the ignition coil body 1 is arranged (hereinafter , This is described as an outer magnet type).

Further, the permanent magnet 12 is a plate-shaped magnet such as samarium-cobalt-based or neodymium-based magnet, which is arranged at an angle θ with respect to the magnetic path, and the closed magnetic circuit cores 10 and 11 are magnetically saturated. A spacer 13 made of a non-magnetic material or a space is provided adjacent to the permanent magnet 12 so as not to cause it.

[0020]

【Example】

 An embodiment of the present invention will be shown below for comparison with a conventional example. First, grain-oriented silicon steel plates having a thickness of 0.3 mm are laminated to form iron cores 10 and 11 having a substantially U-shape and a cross section of 9 mm × 9 mm. Then, the iron cores 10 and 11 are inserted into the primary coil bobbin 2 and the iron core fixing sheath 6 a provided on the insulating case 6. Then, in the primary coil bobbin 2, the iron cores 10 and 11 are joined at the joining portion 11a.

On the other hand, in the iron core fixing sheath 6a, the end faces of the iron cores 10 and 11 are formed at an angle of θ = 40 degrees with respect to the magnetic path, and the iron cores 10 and 11 having a thickness of 1 mm are sandwiched between the end faces. A samarium-cobalt-based permanent magnet 12 and a spacer 13 made of a non-magnetic material and having a thickness of about 0.2 to 0.4 mm or a space is provided to prevent the iron cores 10 and 11 from causing magnetic saturation. There is. The area of the permanent magnet 12 is 9 mm × 14 mm ² = 126 mm ² .

The primary coil 3 is a single wire having a diameter of 0.45 mm wound 140 times. The primary breaking current is 6 A and the magnetomotive force is 780 AT. Further, the secondary coil 5 has a winding number of 1: 100 with the primary coil 3, and in order to secure the dielectric strength, the secondary coil 5 is divided into windings with a collar portion provided on the secondary coil bobbin 4 and divided winding. Has been done. The DC resistance value of the secondary coil 5 is 14 KΩ.

FIG. 2 shows a comparison between the present example (outer magnet type) and the conventional example (inner magnet type) under the above conditions. In any case, the magnetomotive force of the primary coil 3 is set to 780 AT. As can be seen from this, the maximum value of the amount of change in the magnetic flux interlinking with the primary coil 3 is 1.9 × 10 ⁻⁴ (Wb) in the case of the conventional example, whereas it is 2 in this example. It was 4 × 10 ⁻⁴ (Wb).

In the case of the outer magnet type, since the magnetic resistance of the iron core in the portion penetrating the primary coil 3 is extremely small, when the magnetomotive force is the same, the magnetic flux linked to the primary coil 3 This is because the change amount of is increased.

FIG. 3 shows the distribution of the amount of change in the magnetic flux linked to the primary coil 3 in this example and the conventional example under the same measurement conditions. It should be noted that A, B, and C in the drawings all correspond to the positions of A, B, and C shown in FIGS. 1 and 5, respectively.

In the figure, in the case of the conventional inner magnet type, the position where the amount of change in magnetic flux is maximum is A, and at the position C where the permanent magnet 12 is mounted, the amount of change in magnetic flux is A Only 87%. This is because the permanent magnet 12 prevents the change of magnetic flux. Then, the average value of A, B, and C is 94% at the position of A.

On the other hand, in the case of the outer magnet type as in this embodiment, the position where the amount of change in magnetic flux is maximum is B, and the average value of A, B, and C is 97% at the position B. It was This is because the permanent magnet 12 is moved away from the primary coil 3 so that the amount of change in the magnetic flux in the vicinity of the primary coil 3 becomes almost uniform, which changes the magnetic flux at the position B in the center. That is the maximum amount.

Further, the effective primary inductances of the conventional example and the present example are 4.2 mH and 5.4 mH, respectively, which is increased by about 29% in the case of the present example. Further, the coupling coefficients of the primary coil 3 and the secondary coil 5 in the conventional example and the present example are 0.92 to 0.94 and 0.95 to 0.97, respectively, which is much improved in the present example. I understand that.

From the above, if the conditions of the secondary coil 5 in the conventional example and the present example are the same, the primary coil current is cut off by 6 A, and the load on the secondary side is 50 PF. While the secondary voltage is 31.4 KV and the spark energy is 41 mJ, in the case of this embodiment, the secondary voltage is 36.0 KV and the spark energy is 55 mJ. The secondary voltage increases by 15% and the spark energy increases by 34%.

On the contrary, in order to bring out the conventional performance with the configuration of this embodiment, for example, if the thickness of the permanent magnet 12 is 0.7 mm, the number of turns of the primary coil 3 and the secondary coil 5 is reduced by 20%. Therefore, it is possible to significantly reduce the cost. Further, by designing in the middle of the above specifications to achieve both high output and cost reduction, it is possible to provide an inexpensive ignition coil with high output.

In the above description, the permanent magnet 12 is set to an angle of 40 degrees with respect to the magnetic path, but the value of the angle θ may be set to another value. Therefore, FIG. 4 shows the amount of change in magnetic flux when the angle θ 1 at which the permanent magnets 12 are arranged is changed. As can be seen from the figure, when θ is less than 30 degrees, magnetic saturation occurs, and practically the magnetic flux change amount becomes maximum at 30 to 45 degrees. If this is expressed by the area of the permanent magnet 12, 30 degrees is 2.0 times the cross-sectional area of the iron core, and 45 degrees is 1.4 times the cross-sectional area of the iron core.

In general, the larger the area of the permanent magnet 12, the larger the amount of magnetic reverse bias with respect to the iron core can be. However, on the other hand, the permanent magnet 12 has a gap in the forward excitation by the primary coil 3. As the area of the permanent magnet 12 becomes larger, the magnetic resistance becomes smaller and magnetic saturation easily occurs, resulting in a contradiction, which may result in failure to achieve high output of the ignition coil. .

Therefore, it is effective to provide a magnetic saturation preventing gap or a spacer 13 in magnetic series with the permanent magnet 12 as necessary as in the present embodiment. Alternatively, the thickness of the permanent magnet 12 can be selected so that the permanent magnet 12 has a sufficient magnetic resistance.

That is, it is ideal to select the thickness proportional to the area of the permanent magnet 12. Since the grain-oriented silicon steel sheet used in this embodiment is magnetically saturated at a magnetic flux density of about 2.0 Tesla, it is practically efficient to use it at about 1.6 to 1.9 Tesla.

Therefore, when the optimum thickness of the permanent magnet 12 is obtained under the above conditions, the thickness of the permanent magnet having a magnetic flux density of 1.9 Tesla is 0.9 mm, and the numerical value of 0.9 indicates that the angle θ is 40 degrees. The value of 126 of 126 mm ² which is the area of the permanent magnet 12 in is multiplied by 0.0072. The thickness of the permanent magnet with a magnetic flux density of 1.6 Tesla is 1.2 mm, and the numerical value of 1.2 is the numerical value of 126 multiplied by 0.0096. That is, substantially, the optimum thickness of the permanent magnet 12 is the value obtained by multiplying the numerical value of the area of the permanent magnet 12 by 0.007 to 0.010.

Although the present invention has been described above based on the embodiment, the present invention is not limited to the above-described embodiment, and may be modified as long as the configuration described in the claims of utility model is not changed. But you can do it.

[0037]

[Effect of device]

 As described above, the ignition coil for an internal combustion engine according to the present invention has a great effect such as providing an ignition coil that is small in size and capable of obtaining high spark energy, by forming an outer magnet type closed magnetic circuit.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an internal combustion engine ignition coil according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing the amount of change in magnetic flux in the conventional ignition coil and the ignition coil of the present invention.

FIG. 3 A of the conventional ignition coil and the ignition coil of the present invention
It is a characteristic view which shows the distribution of the magnetic flux change amount in each position of -C.

FIG. 4 is a characteristic diagram showing a permanent magnet arrangement angle and a magnetic flux change amount in the ignition coil of the present invention.

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

[Explanation of symbols]

 1 Ignition coil main body 2 Primary coil bobbin 3 Primary coil 4 Secondary coil bobbin 5 Secondary coil 6 Insulation case 6a Iron core fixing sheath 7 Primary terminal 8 High voltage terminal 9 Insulating member 10, 11 Iron core 11a Joint 12 Permanent magnet 13 Spacer A, B, C Magnetic flux variation measurement point α Outer magnet type characteristic curve β Inner magnet type characteristic curve θ Permanent magnet arrangement angle

Claims (4)

[Scope of utility model registration request] 1. A secondary coil is concentrically arranged on the outer peripheral side of the primary coil, and is composed of a coil body integrally molded with an insulating member, and a closed magnetic circuit core made of magnetic metal.
An ignition coil for an internal combustion engine, wherein the coil main body is inserted and arranged in the closed magnetic circuit core, and a permanent magnet is provided in the closed magnetic circuit at a position of the closed magnetic circuit core different from a place where the coil main body is arranged. An ignition coil for an internal combustion engine, which is magnetically arranged in series and has an area of a surface facing the magnetic path of the permanent magnet, which is 1.4 to 2 times the cross-sectional area of the closed magnetic circuit core. . 2. The ignition coil for an internal combustion engine according to claim 1, wherein the thickness of the permanent magnet is 0.0 to the area of the permanent magnet.
An ignition coil for an internal combustion engine, wherein the ignition coil has a thickness multiplied by 07 to 0.01. 3. The ignition coil for an internal combustion engine according to claim 1, wherein the magnetic metal forming the closed magnetic circuit core is a laminated body of grain-oriented silicon steel sheets. 4. A secondary coil is concentrically arranged on the outer peripheral side of the primary coil, and is composed of a coil body integrally molded with an insulating member, and a closed magnetic circuit core made of magnetic metal.
An ignition coil for an internal combustion engine, in which the coil body is inserted into the closed magnetic circuit core to be magnetically connected in series with a permanent magnet disposed in a part of the magnetic path of the closed magnetic circuit core to prevent magnetic saturation. An ignition coil for an internal combustion engine, characterized in that it is provided with a void or a spacer made of a non-magnetic material.