JPS62211910A - Manufacture of magnetic core - Google Patents

Abstract

PURPOSE:To restrain the oscillation in a direction of lamination in a gap part by impregnating the spaces among layers of a magnetic core formed by winding a magnetic thin plate into a laminar body with a resin and forming a gap penetrating in a direction of the lamination and fixing a part near the gap of the magnetic core. CONSTITUTION:Spaces among layers of magnetic thin plates 11 are impregnated with a resin 12 uniformly. A gap 13 penetrating in a direction of lamination of the thin plates 11 is formed. In the gap 13, a spacer 15 made of a thin non- magnetic plate is inserted and is fixed with an adhesive 16. Spaces among the thin plates 11 are impregnated again with the resin. As a result, removed parts 14 of the resin 12 are also filled with the resin 17. Then, the oscillation in a direction of the lamination in the gap part 13 is restrained.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention relates to a method for manufacturing a magnetic core, and particularly to a method for manufacturing a magnetic core, which is constructed by laminating and winding magnetic thin plates, and having a gap penetrating in the lamination direction. The present invention relates to a method of manufacturing a magnetic core having the following.

(Prior Art) In an output choke coil or the like in a switching power supply, as shown in FIG. 4, a magnetic core 1 is formed by laminating and winding magnetic thin plates made of an amorphous alloy or the like and forming a gap 2 passing through the lamination direction. is used. Such a magnetic core is usually manufactured by a process of laminating and winding magnetic thin plates, impregnating resin between the layers, and then forming a gap.

(Problems to be Solved by the Invention) When the above-mentioned conventional magnetic core is used under a condition where the current is periodically turned on and off, such as in an output choke coil in a switching power source, the switching frequency may change. In the case of an audible frequency such as several kl-1z,
There was a problem in that the core vibrated and generated harsh noise.

The inventors investigated the mechanism of noise generation described above and found that the magnetic field applied to the core through the coil causes expansion and contraction (magnetostriction) of the core in the direction of the magnetic path, and this expansion and contraction movement causes the magnetic thin plate to It was determined that the cause of the noise was that the gap was converted into vibration in the lamination direction in the free state.

The present invention has been made to solve these conventional problems, and provides a method for manufacturing a magnetic core that generates less unpleasant noise even when the current in the coil is turned on and off at an audible frequency. The purpose is to

[Structure of the Invention] (Means for Solving the Problems) The present invention impregnates a resin between the layers of a magnetic core formed by winding magnetic thin plates in a laminated manner, forms a gap penetrating in the lamination direction, and then It is characterized by fixing the portion of the magnetic core near the gap.

Here, as a method for fixing the portion of the magnetic core near the gap, for example, it is effective to impregnate the resin between the layers of the magnetic core again.

Other methods for fixing the portion of the magnetic core near the gap include applying adhesive to the portion near the gap, or sandwiching the portion near the gap between non-magnetic fixing members from both sides in the stacking direction of the magnetic thin plates. It will be done.

(Function) If a gap is formed that penetrates in the lamination direction after impregnating resin between the layers of a magnetic core made of laminated and wound magnetic thin plates, the resin between the layers in the vicinity of the gap will peel off, causing the magnetic thin plates to However, if the portion of the magnetic core near the gap is forcibly fixed based on the present invention, the core will expand and contract in the direction of the magnetic path due to the magnetic field applied to the core. Also, vibration in the stacking direction at the gap between the thin magnetic plates, which causes noise generation, is suppressed.

(Example) A method for manufacturing a magnetic core according to an example of the present invention will be described with reference to FIG. First, as shown in FIG. 1 (a), magnetic thin plates 11 made of an amorphous alloy or the like are laminated and wound into a toroidal shape as shown in FIG. 4, for example, and then impregnated with resin.

Resin impregnation is a method of impregnating resin into the gap using negative pressure, and through this process, the resin 12 is uniformly impregnated between the layers of the magnetic thin plate 11, as shown in FIG. 1(a). .

Next, as shown in FIG. 1(b), a gap 13 penetrating the magnetic thin plates 11 in the stacking direction is formed. gap 1
3 may be formed using, for example, a suitable cutter. Here, looking at the state after forming the gap 13, the impregnated resin 12 peels off and falls off between the layers of the magnetic thin plate 11 in the vicinity of the gap 13, as shown at 14 in FIG. 1(b). ing.

Next, as shown in FIG. 1(C), a spacer 15 made of a thin non-magnetic plate is inserted into the gap 13 and fixed with an adhesive 16. The conventional manufacturing process for magnetic cores is
Although the process up to the step shown in FIG. 1(C) was performed, in this example, resin impregnation is performed again. As a result of this second resin impregnation,
As shown in FIG. 1(d), the part 14 of the resin 12 that has fallen off in FIGS. 1(b) and 1(c) is also impregnated with the resin, so that the portion of the magnetic thin plate 11 near the gap 13 is made of magnetic material. The thin plates 11 are firmly fixed in the stacking direction.

Therefore, when the coil wound around the magnetic core is intermittently energized, even if the core expands and contracts in the direction of the magnetic path due to the application of a magnetic field, the accompanying vibration of the magnetic thin plate 11 in the vicinity of the gap 13 is effectively suppressed and noise generation is significantly reduced. According to experiments, the level of noise generated by a magnetic core based on the conventional technology in which resin impregnation was performed only once at the beginning was approximately 70 dB, whereas resin impregnation was performed again after the above-mentioned gap 13 was formed. The magnitude of the noise generated by the magnetic core according to the present invention was significantly reduced to approximately 45 dB under the same operating conditions.

In the above embodiment, after the gap was formed, the core was impregnated with resin again to fix the core near the gap, but in another embodiment, as shown in FIG. 2, the spacer shown in FIG. 1 was fixed in the core near the gap. Adhesive 18 (for example, resin adhesive) in addition to adhesive 16 for fixing 15
may be applied.

As another embodiment, as shown in FIG. 3, the core near the gap may be sandwiched between plate-shaped fixing members 19 made of a non-magnetic material such as aluminum from both sides in the stacking direction of the magnetic thin plates. good.

In any of these embodiments, the same noise reduction effect as in the previous embodiment can be obtained. The present invention can be implemented with various other modifications without departing from the scope of the invention.

[Effects of the Invention] According to the method for manufacturing a magnetic core according to the present invention, a magnetic core that generates little noise can be obtained even when used in a switching power supply where the coil current is turned on and off at an audible frequency. be able to.

[Brief explanation of drawings]

FIGS. 1(a) to (d) are process diagrams for explaining a method of manufacturing a magnetic core according to an embodiment of the present invention, and FIG. 2(a) (
b) is a plan view for explaining another embodiment of the present invention and an enlarged view showing a portion near the gap; FIG. 3 is a plan view for explaining another embodiment of the present invention and a diagram showing the vicinity of the gap FIG. 4, which is a partially enlarged view, is a plan view for explaining the magnetic core to which the present invention is directed. DESCRIPTION OF SYMBOLS 1... Magnetic core, 2... Gap, 11... Magnetic thin plate, 12... Resin, 13... Gap, 14...
...Resin falling part, 15...Spacer, 16...Adhesive, 17...Resin, 18...Adhesive, one...
Fixed member. Applicant's agent Patent attorney Takehiko Suzue 1'IjD (a) 2nd (a) 3rd (b) Figure

Claims (4)

[Claims] (1) Magnetism characterized by impregnating resin between the layers of a magnetic core formed by laminating and winding magnetic thin plates to form a gap penetrating in the lamination direction, and then fixing a portion of the magnetic core near the gap. Core manufacturing method. (2) The method for manufacturing a magnetic core according to claim 1, characterized in that in order to fix a portion of the magnetic core near the gap, resin is again impregnated between the layers of the magnetic core. (3) The method for manufacturing a magnetic core according to claim 1, characterized in that an adhesive is applied to a portion of the magnetic core near the gap in order to fix the portion of the magnetic core near the gap. (4) In order to fix the portion of the magnetic core near the gap, the portion near the gap is sandwiched between non-magnetic fixing members from both sides in the stacking direction of the thin magnetic plates. A method for manufacturing a magnetic core.