JP3844162B2 - Coil with magnetic core - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a choke coil such as a booster circuit of an EL drive circuit and a magnetic core containing coil such as a transformer.
[0002]
[Prior art]
A few examples of conventional magnetic core-containing coils are shown in FIG. 5. In FIG. 5, a winding frame having a flange 3 formed on both ends of a magnetic core 1 is manufactured by winding a ferrite powder magnetic body. 2 is rolled up.
In FIG. 6, a winding 2 is wound around an I-shaped magnetic core 1 obtained by pressing a metal magnetic material plate such as permalloy or a silicon steel plate.
FIG. 7 shows a coil for a spindle motor. In order to reduce the eddy current loss, the magnetic core 1 is formed by laminating a plurality of silicon magnetic plates 4 having a thickness of about 0.3 to 0.5 mm. This is provided with a winding 2, and 5 is a pin provided by half-cutting the magnetic plate 4 of each layer, and by inserting the half-cut pin 5 into a half-cut hole of the magnetic plate 4 overlapping above or below. All the magnetic plates 4 are arranged.
FIG. 8 shows a coil containing a magnetic core in which a winding 2 is wound around a magnetic core 1 in which a magnetic plate 4 made of permalloy or a silicon steel plate is similarly laminated. The magnetic core has a C-shape.
[0003]
[Problems to be solved by the invention]
The conventional magnetic core-containing coils as described above have the following problems. That is, in the case of FIG. 5 in which the magnetic core 1 is made of a ferrite-based powder magnetic material, the magnetic flux density of the powder magnetic material is lower than that of the metal magnetic material. It is necessary to prevent downsizing. In addition, the manufacturing cost of powder molding is also higher than that of pressing a metal plate.
[0004]
6 that presses the metal magnetic material plate to make the magnetic core 1 is superior to the powder molded product of FIG. 5 in terms of magnetic characteristics and ease of processing, but is disadvantageous in terms of eddy current loss as described below. Become. The eddy current loss We of the magnetic material per unit time and unit volume is expressed by the following equation.
We = σt ² f ² B ²
Here, σ is a proportional constant, t is the plate thickness, f is the frequency of the magnetic field, and B is the maximum magnetic flux density.
According to this equation, the eddy current loss rapidly increases as the plate thickness increases. Therefore, it is effective to reduce the plate thickness in order to suppress this. Therefore, in the motor coil shown in FIG. 7, the magnetic core 4 is formed by superposing one thin magnetic steel plate 4 of a silicon steel plate whose surface is insulated. Since there is a limit to reducing the plate thickness because the magnetic plates are connected to each other, it cannot be reduced to 0.3 to 0.5 mm or less as described above, and it is difficult to further reduce the thickness, size, and performance. Met. The present invention is directed to overcoming these problems associated with magnetic cored coils.
[0005]
[Means for Solving the Problems]
In the present invention, in the magnetic core-containing coil, a metal magnetic material plate such as permalloy, silicon steel plate or the like whose surface is insulated is folded and overlapped to obtain a necessary magnetic flux. Since this is an integral structure in which each magnetic plate is connected at the bent portion, it is not necessary to provide a half punch pin on each plate in order to align separate plates as described above, and the plate thickness is significantly thinner than before. Thus, the eddy current loss of the magnetic core can be reduced. In terms of processing, it can be efficiently manufactured with a progressive press die.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is used about the same kind components and parts including the said description.
FIG. 1 shows one embodiment of a coil with a magnetic core according to the present invention, in which windings are partially cut off. The magnetic core 1 has a rod-like I-shape similar to that shown in FIG. 6. However, the magnetic core 1 is not a single piece as shown in FIG. 6, but a three-layer structure by bending a magnetic thin plate such as permalloy or silicon steel plate whose surface is insulated. The winding 2 is given to this. The thickness of the magnetic material plate is about 0.05 to 015 mm, and in some cases, it can be made smaller. This is much thinner than the conventional 0.3-0.5 mm.
[0007]
The developed shape of the magnetic core 1 is as shown in FIG. 2, and there are connecting portions 6 and 7 of each layer on both sides, and the fold line 8 and the fold line 9 are bent in opposite directions. This is a shape in which the I-shapes are connected side by side, but as can be easily understood, the expanded shape of the I-shaped magnetic core is, for example, a shape in which the I-shapes are vertically stacked, and the boundary of the stack is a bent portion. In other words, the point is to provide a connecting portion between layers in a part of the contour of the magnetic core.
[0008]
In the magnetic core 1 having such a structure, even if the entire thickness is somewhat large, the individual magnetic plates 4 are thin and insulated from each other, so that the eddy current loss calculated by the above formula is small. Normally, the surface of a magnetic material plate is oxidized in the raw material manufacturing process to produce an insulating layer. However, in order to ensure, the surface is treated to form an insulating film.
[0009]
FIG. 3 shows a second embodiment of the present invention in which a part of the winding wire is cut out. The magnetic core 1 has a C-shape similar to that shown in FIG. The magnetic plate 4 is laminated in three layers by bending a thin magnetic plate material, and the winding 2 is applied with both ends curved in a C shape. The developed shape of the magnetic core 1 is as shown in FIG. 4, and there are connecting portions 6 and 7 of each layer at the center, and the fold line 8 and the fold line 9 are bent in opposite directions.
[0010]
In the case of such a C-shaped magnetic core, bending the thin plate material into the magnetic core 1 according to the present invention has the following advantages in addition to the reduction of the eddy current loss. When the magnetic core material is a grain-oriented silicon steel sheet, the magnetic characteristics are directional and not uniform, and when a magnetic field is applied parallel to the rolling direction, the relative permeability is the highest and the hysteresis loss is reduced. Therefore, for example, in the conventional example of FIG. 8, when the relationship between the C-shape of the magnetic core 1 punched out of the silicon steel plate and the rolling direction 10 is as shown in the figure, in the portion of the magnetic core including the winding portion and the air gap on the opposite side, Although the magnetic path is parallel to the rolling direction 10 and is in good condition, the magnetic path is perpendicular to the rolling direction and is not preferred in a portion that is orthogonal to these and connects both sides. Even if improvement is intended, the C-shaped arrangement is inclined by 45 ° with respect to the rolling direction to average the characteristics.
[0011]
However, in the case of the present invention, if the length of the developed shape of the magnetic core 1 in FIG. 4 is oriented in the rolling direction 10 of the silicon steel sheet, the C-shaped magnetic path in the completed shape in FIG. Thus, the magnetic core having the most excellent magnetic characteristics is obtained. A magnetic core that minimizes iron loss can be obtained by combining the reduction in eddy current loss and the reduction in hysteresis loss due to the reduction in plate thickness.
[0012]
In the case of the motor coil shown in FIG. 7 as well, although not shown in the drawing, when considering a shape in which a connecting portion with an adjacent layer is provided on a part of the outer periphery of each magnetic plate 4 and developed in a chain shape, this is folded and overlapped. Thus, it will be understood that a laminated magnetic core can be obtained without connecting the half-cut pins 5.
In order to manufacture the magnetic core of each of the above embodiments, it is possible to punch a blank having a developed shape as shown in FIGS. 2 and 4 from a magnetic material plate, and to bend it into a finished shape. If progressive press die processing is used, a magnetic core having a finished shape can be obtained directly from the strip, and can be manufactured with very high productivity.
[0013]
【The invention's effect】
As described above, the magnetic core-containing coil of the present invention has a magnetic core obtained by bending and laminating metal magnetic material plates, and can be reduced in size and thickness as compared with a powder molded one. Because of the structure, the current loss is smaller than that of a single piece magnetic core of metal magnetic material. Compared to the laminated press-cut magnetic plates, it is not necessary to provide a half punch pin in the magnetic core, so the plate thickness can be made thinner than before, the eddy current loss is smaller, and the magnetic path is curved. In the case of what is done, the total length of the magnetic path can be matched to the rolling direction of the material, and iron loss is reduced. The magnetic core-containing coil of the present invention is suitable for manufacturing by a progressive press die, whereby a small and high-performance magnetic core-containing coil can be provided at low cost.
[Brief description of the drawings]
FIG. 1 is a perspective view of a part of a coil with magnetic core according to the present invention.
FIG. 2 is a development view of the magnetic core of the coil with a magnetic core in FIG.
FIG. 3 is a perspective view of a part of another coil with magnetic core according to the present invention.
4 is a development view of the magnetic core of the coil with a magnetic core shown in FIG. 3;
FIG. 5 is a perspective view of a conventional coil with a magnetic core.
FIG. 6 is a perspective view of another conventional coil with a magnetic core.
FIG. 7 is a perspective view of a conventional motor coil.
FIG. 8 is a perspective view of another conventional coil with a magnetic core.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Magnetic core 2 Winding 4 Magnetic board 5 Half punching pins 6, 7 Connection part 8, 9 Bending line 10 Rolling direction

Claims (1)

In a coil with a magnetic core in which a magnetic core is wound,
The magnetic core in which the surface are laminated by bending a magnetic metal material plates that are insulated, is provided with a connecting portion of the interlayer in a part of the contour, have a shape both ends of which are curved, the interlayer in a substantially central portion of the shape The magnetic core-containing coil is provided with a connecting portion.

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