JPS6015908A - Magnetic core - Google Patents

Abstract

PURPOSE:To obtain a magnetic core to present a nonlinear inductance characteristic having a superior direct current superposing characteristic by a method wherein a lamellar soft magnetic substance is arranged between the central leg of an E type core, etc. and the legs on both sides thereof, and an I type core is arranged thereon. CONSTITUTION:A magnetic core is constructed of an E type core 1 and an I type core 2 consisting of ferrite, etc. and a lamellar soft magnetic substance 3. When the soft magnetic substance 3, the E type core 1 and the I type core 2 are superposed directly, inductance at low current time rises to form a nonlinear characteristic arised from the difference of the magnetic characteristics when used for a choke coil, etc. When soft magnetic substances 3a divided into two parts are arranged, a nonlinear characteristic can be obtained similarly, and the direct current superposing characteristic can be changed arbitrarily by changing the interval between the divided soft magnetic substances.

Description

[Detailed description of the invention] The present invention relates to improvements in ET type magnetic cores.

Conventionally, as magnetic cores for choke coils and magnetic cores for high frequency lances, El cores such as Ferrai 1 and EE cocoa have been mainly used.

However, these magnetic cores exhibit linear characteristics in which magnetic permeability is approximately constant until the core approaches saturation, and therefore, these cores do not have sufficient characteristics as smoothing chokes for switching power supplies. That is, when a magnetic core with such normal linear characteristics is used as a choke core, the inductance does not increase even at low currents, and the output voltage increases when the load current is small, causing problems. For this reason, this problem is usually solved by creating a circuit that reduces output voltage fluctuations.

Therefore, it is not desirable in terms of problems such as an increase in cost due to the increase in the number of parts, an increase in the size of the power supply due to the increase in the number of parts, and a decrease in efficiency.

For this purpose, a magnetic core with good DC, heavy, and E characteristics is required, which has a large inductance when the current flowing through the coil is small, and whose inductance is approximately constant from a certain current level up to a current at which the magnetic core is saturated.

In order to solve this problem, proposals have been made for magnetic cores such as El cores and EE cocoas that have a step formed on the joint surface to form a gill.

However, in order to do this, it is necessary to sharpen a part of the joint surface with high precision, which requires a lot of man-hours and is technically 1
There are some difficult aspects. Furthermore, materials such as ferrite have a low saturation magnetic flux density, and sufficient direct rAL superimposition characteristics cannot be obtained on the low current side.

Therefore, there are problems such as an increase in the number of windings and an increase in the size of the core.

SUMMARY OF THE INVENTION An object of the present invention is to improve the drawbacks of the prior art described above and provide a magnetic core that exhibits nonlinear inductance characteristics with excellent DC superimposition characteristics.

The gist of the present invention is that a plate-shaped soft magnetic material is arranged between a central leg such as an E-shaped core and the legs on both sides thereof, and an I-shaped core is arranged thereon.

When a ferromagnetic ribbon is used as a soft magnetic material, the transmission vJ of low magnetic field is
This is preferable because the frequency dependence of the 1 rate can be reduced. Furthermore, when Arufus thin strip is used, it can be easily formed by photo-etch lamination 1 and then cutting, and it also has excellent high frequency characteristics and has a higher saturation magnetic flux density than Ferrai 1~ etc., so it has excellent DC superimposition characteristics. can be improved and more favorable results can be obtained.

Further, by arranging a non-magnetic spacer between the soft magnetic material arranged in the leg portion and the I-shaped core, it is possible to arbitrarily change the DC superposition characteristic.

The soft magnetic material placed in the leg portions may not be placed on all the legs, but may be placed only near two legs.

Furthermore, the DC superimposition characteristic, which is non-linear, is achieved by adding a crystal to the I-shaped core and changing the width of the soft magnetic material placed in the legs to an E-shaped core.

It can also be changed arbitrarily by making it smaller than the width of the I-type core.

It is clear that the same effect can be obtained by forming a soft magnetic film by a method such as sputtering or vapor deposition in place of the ferromagnetic ↑4 thin ribbon, and the same effect is obtained and it is within the scope of the present invention. E
It is clear that the scope of the present invention also includes the use of a mold core (similar in shape to the mold core).

The magnetic core according to the invention is particularly suitable for output type iA switching power supplies.
The effect is remarkable when used in smoothing chalk.

Hereinafter, the present invention will be explained based on 31 examples.

Embodiment 1 FIG. 1 shows a portion of an embodiment of the magnetic core of the present invention. As shown in the figure, the magnetic core according to the present invention includes an E-type magnetic core 1 made of J-light or the like, an )-type magnetic core 2, and a plate-shaped soft magnetic body 3.

(21) is a case where the soft magnetic 1-hole 3 and the ``type magnetic core 1 and 1-type magnetic core 2 are directly superimposed, and due to the difference in magnetic properties, when used in a jog coil, etc., the inductance at low current increases and the nonlinear characteristics becomes.

(1)) is a case where a soft magnetic body 3a divided into two is arranged, and as in (a), nonlinear characteristics are obtained, and by changing the interval between the divided soft magnetic bodies, the DC superposition characteristic can be adjusted arbitrarily. can be changed to

(C) is a case in which a nonmagnetic spacer is inserted between the soft magnetic material and the I-type magnetic core, and nonlinear characteristics can also be obtained. The DC superposition characteristics can be changed arbitrarily by changing the thickness of the spacer. (d) is a platform on which a soft magnetic material 3b whose width is smaller than the width of the ■-shaped magnetic core and the E-shaped magnetic core is arranged, and by changing the width, the DC superposition characteristics can be changed. (
e) When a non-magnetic spacer 4a is placed on one leg and a soft magnetic 1ff integral 3G is placed between the center leg and the opposite side 4, <
f) is when the groove 5 is placed in the I-type magnetic core, (g) is when the soft magnetic 1-hole 3d is placed below the I-type magnetic core between the legs of the E-type magnetic core, and (h) is when two or more This is the case where an I-shaped core 2a divided into 1ζ is arranged, and all structures exhibit nonlinear 1°j property.

Embodiment 2 FIG. 2 is a diagram showing an example of the DC superposition characteristics of the magnetic core of the present invention. For comparison, the DC superposition characteristics when two soft magnetic bodies are not arranged are also shown.

As is clear from the figure, the inductance increases when the current flowing through the coil is small, and it can be seen that No. 17 is superior as a magnetic core for a smoothing choke in a switching power supply.

According to the present invention, inductance at low current is improved,
Moreover, the DC superimposition characteristics are superior to conventional cores, and the fabrication is easy, so the effect is remarkable.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a part of an embodiment of the magnetic core of the present invention, and FIG. 2 is a diagram showing an example of the DC superposition characteristic of the present invention. Figure 1 2nd IDc (A)

Claims (1)

[Claims] 1. A magnetic core characterized in that a plate-shaped soft magnetic material is arranged between a central leg of an E-shaped core and the legs on both sides thereof, and an I-shaped core is arranged above A. 2. A magnetic core according to claim 1, characterized in that a ferromagnetic ribbon is laminated on a plate-shaped soft magnetic material arranged in the leg portion of an E-shaped core or the like, or a single ferromagnetic ribbon is used alone. . 3. The magnetic core according to claim 2, characterized in that an amorphous ribbon is used as the ferromagnetic ribbon. 4. The magnetic core according to claim 1, 2, and 3, characterized in that a non-magnetic spacer is arranged between the soft magnetic 1-hole and the I-shaped core arranged in the leg part. . 14 characterized by having a groove in the center of the 5.1 type core.
A magnetic core according to claims 1, 2, 3, and 4. 6. Claim 1, characterized in that the width of the soft magnetic material is smaller than the width of the E-type and I-type cores. The magnetic core according to Items 2, 3, and 4. 7. Claims 1, 2, 3, 4, and 6 characterized in that the ■-shaped core is cut and arranged.
Magnetic core described in section. 8. Claim 1, characterized in that it is used as a choke for output current conditions of a switching power supply. Sections 2, 3, 4, 5, 6 and 7
Magnetic core described in section.