JPS59231806A - Magnetic core for normal mode noise filter - Google Patents

Abstract

PURPOSE:To obtain a normal mode noise filter core with excellent DC superposition characteristics and frequency characteristics of impedance by introducing an amorphous core with a gap instead of a conventional dust core such as ferrite core. CONSTITUTION:When an amorphous core is subjected to a heat treatment, the amorphous becomes brittle and the core is hard to cut under that condition. Therefore, the core is impregnated with a resin of epoxy system or the like. Sometimes a gap of the amorphous core changes after cutting. Therefore, a non- magnetic spacer is provided to the gap part so that the dispersion of characteristics and the change of the characteristics caused by an impact can be avoided. Moreover, by coating of an insulation resin applied on the amorphous core, insulation against a winding and strength of the core are improved and the deterioration of the characteristics is avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a magnetic core for a normal mode noise filter.

Conventionally, as magnetic cores for normal mode noise filters, fully flexed powder magnetic cores made of permalloy, iron powder, etc., and Ferrai 1 cores have been mainly used.

Since powder magnetic cores do not have gear teeth, there is no problem of noise generation due to leakage magnetic flux, and although the frequency characteristics are relatively good, the magnetic permeability is 1 degree, so when used as a bulk core, the impedance is low and although the characteristics are not necessarily the same, There wasn't.

On the other hand, since the saturation magnetic flux density of Ferrai 1 core is low at around 5000G, if a Gi 1 tube is made to obtain a sufficient saturation magnetic field, the magnetic permeability of the core will be IL (when used as a curved choke, sufficient It's hard to call it a characteristic.
:The frequency characteristics are also inferior compared to powder magnetic cores.

The present invention improves the drawbacks of the above-mentioned prior art, and improves the DC superimposition characteristics.
The purpose is to provide a magnetic core for normal moat noise filters with excellent impedance frequency characteristics.

The main point of the present invention is that by using an amorphous magnetic core in place of the fly core of the powder magnetic core conventionally used for normal mode noise filters,・Is the magnetic core for the normal ■-tone noise filter 1'?
That's true.

Normally, amorphous magnetic cores are heat-treated.When heat-treated, amorphous becomes brittle. It is better to use a morphous type (contains 2 tons of Ebogishi type fat) to handle the soil when cutting.

Also, with amorphous magnetic cello, the grip may change after it is cut, so it is better to place a non-magnetic spacer in the grip to prevent variations in characteristics and changes in characteristics due to peak impact, thereby obtaining favorable results. The temperature drops to °C.

The saturation magnetic flux density of iron-based amorphous is much higher than that of Permalloid Dame 1-Core and Fly J Fly 1-, so it is extremely (
It is possible to reduce the DC superimposition characteristic by 1q.

Furthermore, it is preferable to core-fing the amorphous magnetic core with an insulating resin to increase the insulation of the windings and the strength of the magnetic core, and to prevent the poor IL described in Part ↑1.

In order to prevent noise from the I7 knob, it is more preferable to shield the vicinity of the gear with a thin metal strip or metal plate in order to enhance the noise reduction effect.

Hereinafter, E7i1jJj will be explained based on examples.

Example 1 FIG. 1 is a diagram showing the frequency dependence of magnetic permeability ll' (real part) and μI+ ((4r part) in an example of the magnetic core according to the present invention. For comparison, It can be seen that the MO Vermaro r pressure i5) Kik core is more saturated than the MO Permanent powder magnetic core over a wide frequency range.

Embodiment 2 FIG. 2 is a diagram showing the frequency dependence of the absolute value 1h1 of jn magnetic coefficient in an embodiment of the magnetic core according to the present invention. The core using ζ7morphous is very superior lζ frequency 11
You can see that it shows gender.

Embodiment 3 FIG. 3 is a diagram showing the frequency dependence of the impedance IZ1 of a magnetic core according to an embodiment of the present invention having 45 5-turn windings. The shapes of &J are the same.

The impedance characteristics are also far superior to ~10 permalloy powder magnetic core in a wide frequency range, and it can be seen that it is advantageous as a noise filter.

Embodiment 4 FIG. 1 is a diagram showing the DC superimposition characteristics of the magnetic core according to the present invention with different gears and protrusions. -xi! t-tub is r=
Compared to MO Permalox i-Core, C
It exhibits much better DC superimposition characteristics.

Example 5 FIG. 5 is a diagram showing the frequency dependence of iron loss in an example of the magnetic core according to the present invention. It can be seen that it exhibits excellent frequency characteristics comparable to that of MO permalloid dust.

According to the present invention, the DC superimposition characteristic (9 frequency characteristics) of the magnetic core, which had been a problem in the past, can be improved by using a magnetic core for a normal .tau.-noise filter, and the practical effects are extremely good.

[Brief explanation of the drawing]

FIG. 1 shows the magnetic permeability μ in one embodiment of the magnetic core according to the present invention.
Figure 2 shows the frequency dependence of the absolute value IQI of magnetic permeability in one embodiment of the magnetic core according to the present invention. Figure shown, 3rd
The figure shows the frequency dependence 11 of the impedance i71 in one embodiment of the magnetic core according to the present invention, and FIG. 4 shows the DC superposition 14r when the gear 1j of the magnetic core according to the present invention is changed.
FIG. 5 is a diagram showing frequency dependence of iron loss in an embodiment of the magnetic core according to the present invention. Fig. 3 Nvc (θe) Fig. 5 f (kHz)

Claims (1)

[Scope of Claims] 1. A normal mode noise free magnetic core using an amorphous magnetic core provided with a magnetic core as a Ti characteristic. 2.Special W characterized by being impregnated with an amorphous magnetic core
Range of 1 item Normal mode noise described in item 1
Magnetic core for Luther. 3. The magnetic core for a normal mode noise filter according to claims 1 and 2, characterized in that a non-magnetic spacer is disposed in the grip portion. 4. Claim 1, characterized in that amorphous ridges are used as the amorphous magnetic core. A magnetic core for a normal ■-denoise filter as described in Items 2 and 3. 5. The magnetic core was made of insulating resin] - 12
(2) A magnetic core for a normal Lutter according to claims 1, 2, 3, and 4. 6. Claim 1, characterized in that the vicinity of the 17 knob of the gold B ribbon or metal plate is shielded;
The magnetic core for a normal 1-tonneau 1' filter as described in items 2, 3, 4, and 5.