JPH11186060A - Inductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make manufacture of a wound iron core and, in its turn, an inductor easier by forming the wound iron core by winding a steel sheet having a specific value or smaller in the ratio of residual magnetic flux density to saturated magnetic flux density a plurality of turns and, after protecting the wound iron core with an insulator, winding a coil around the insulator. SOLUTION: A wound iron core 1 is formed by winding a steel sheet having <=0.35 in the ratio (Br/Bs) of residual magnetic flux density (Br) to saturated magnetic flux density (Bs) a plurality of turns. At the time of forming the core 1, a silicon steel sheet in which the silicon concentration is adjusted in such a way that the concentration is increased as going toward the surface from the center in the thickness direction. Specifically, the concentrations in the central layer and surface layer of the steel sheet in the thickness direction are respectively adjusted to 3.0% and 6.5%. Then the core 1 is protected with an insulator 2 which is a case made of an insulating material, and a coil 5 is wound around the insulator 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inductor, for example, a noise absorbing inductor for absorbing noise generated in a power supply line in a normal mode, and a smoothing circuit. The present invention relates to a choke coil such as an inductor for reducing an inrush current to a capacitor.

[0002]

2. Description of the Related Art FIGS. 5 and 6 show a conventional choke coil of this kind. First, a method for manufacturing the choke coil shown in FIGS. 5 and 6 will be described. As shown in step S101 of FIG.
Grain-oriented silicon steel sheet having a thickness of 0.23 mm (silicon steel sheet having a silicon concentration of 3.5%) indicated in the characteristics of C-2553
Prepared by slitting to a width of 15 mm. The prepared silicon steel sheet 101 is subjected to, for example, a known method as shown in step S102 of FIG.
The winding body 102 is formed by winding 27 times. The wound body 102 at this time has an inner diameter of, for example, 23 mm and an outer diameter of 36 m.
m.

The above-mentioned silicon steel sheet 101 has DC magnetic characteristics as shown in FIG.
Is as high as 1.7 Tesla [T], and the initial characteristic of the magnetic flux density B with respect to the magnetic field strength H (curve A shown in FIG. 7) rises steeply. As a result, when an inductor is formed by using the wound body 102 as it is as a wound iron core, the permeability μ suddenly decreases when the current flowing through the coil increases, and the inductance decreases when the permeability μ decreases. That is, as shown by the curve a in FIG. 4, when the current (direct current superimposed current) flowing through the coil increases, the inductance sharply decreases, so that it can be used only for a current in a very small range. It is not practical.

Therefore, conventionally, a gap is formed in the above-mentioned wound body 102, the residual magnetic flux density Br is set to almost 0, and the initial characteristic of the magnetic flux density B with respect to the magnetic field strength H is gradually increased to form an inductor. In this case, even if the current flowing through the coil increases, the magnetic permeability μ is prevented from sharply decreasing. That is, the above-mentioned wound body 102
Then, heat treatment is performed as shown in step S103 of FIG. 5, and then, as shown in step S104 of FIG. 6, the wound body 102 is impregnated with a resin, and the wound body 102 itself is fixed. The wound body 102 impregnated with this resin is partially cut as shown in step S105 of FIG.
03 is formed.

[0005] Next, as shown in step S106 of FIG.
The resin body 105 is loaded into the gap 103 while being housed in the main body 104. The wound body 102 loaded with the resin body 105 functions as a wound core 106. This winding core 1
No. 06 has magnetic properties as shown in II of FIG. 3, the residual magnetic flux density Br is almost 0 (0.05T), and the magnetic field strength H
Rise of the initial characteristic of the magnetic flux density B (the straight line B shown in FIG. 3) with respect to.

Next, as shown in step S106 of FIG. 6, the lid 107 is bonded to the main body 104, and
To an insulator 108 formed by the main body 104 and the lid 107.
Store in and protect. Next, an enamel wire is wound around the insulator 108, for example, 26 times to form a coil 109. Both ends of the coil 109 are drawn out
For example, if the power supply line is used for absorbing noise, the lead portion 110 is connected to the power supply line.

In the inductor configured as described above, the magnetic permeability μ does not decrease rapidly even when the current flowing through the coil increases, and the magnetic permeability is substantially constant over a wide range of current. . As a result, as shown by the curve b in FIG. 4, the inductance is substantially constant even when the current (direct current superimposed current) flowing through the coil increases. Therefore, a substantially constant inductance is obtained for a wide range of current (DC superimposed current), and it can be used as a choke coil.

[0008]

However, in order to form the wound iron core 106, the choke coil configured as described above heat-treats the wound body 102, impregnates the resin,
Formation of gap 103, resin body 10 in gap 103
5 had to be performed.

The present invention has been made in view of the above points, and has as its object to provide an inductor that is easy to manufacture a wound core and that is easy to manufacture an inductor.

[0010]

The inductor according to the first invention is obtained by winding a steel sheet having a ratio of residual magnetic flux density to saturated magnetic flux density (residual magnetic flux density / saturated magnetic flux density) of 0.35 or less a plurality of times. It is provided with a wound core formed, an insulator for protecting the wound core, and a coil wound around the insulator.

According to a second aspect of the present invention, there is provided an inductor which is formed by winding a silicon steel sheet having a high silicon concentration a plurality of times from the center to the surface in the thickness direction, and an insulator for protecting the wound core. And a coil wound around the insulator.

In the inductor according to a third aspect of the present invention, the silicon concentration in the center layer in the thickness direction is 2.5 to 3.5%, and the silicon concentration in the surface layer in the thickness direction is 6.0 to 3.5%.
It is provided with a wound iron core formed by winding a 7.0% silicon steel sheet a plurality of times, an insulator protecting the wound iron core, and a coil wound around the insulator.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 First Embodiment A first embodiment of the present invention will be described with reference to FIGS. In the figure, 1 is the ratio of the residual magnetic flux density (Br) to the saturated magnetic flux density (Bs) (residual magnetic flux density / saturated magnetic flux density = Br / B
s) is a wound iron core formed by winding a steel sheet having a diameter of 0.35 or less, and in Embodiment 1, a silicon steel sheet having a high silicon concentration from the center to the surface in the thickness direction, specifically, a sheet The silicon concentration of the central layer in the thickness direction is 3.0%,
It is formed by winding a silicon steel sheet having a silicon concentration of 6.5% in the surface layer in the thickness direction in multiple turns.

Reference numeral 2 denotes an insulator, which is a case formed of an insulating material for protecting the wound iron core. In the first embodiment, a body 3 having a donut-shaped bottom and a cylindrical inner wall and an outer wall connected thereto is provided. And a lid 4 having a donut-shaped bottom and a cylindrical inner wall and an outer wall connected thereto, and the end faces of the inner and outer walls of the main body 3 and the end faces of the inner and outer walls of the lid 4 are fixed with an adhesive. You. Reference numeral 5 denotes a coil wound around the insulator. In the first embodiment, the coil is formed by winding an enamel wire, for example, 26 times. If it is used for absorption, the lead-out section 6 will be connected to the power supply line.

Next, a description will be given of a method of manufacturing the inductor which becomes the choke coil configured as described above. First, as shown in step S1 of FIG. 1, a silicon steel sheet in which the silicon concentration of the central layer in the thickness direction is 3.0% and the silicon concentration of the surface layer in the thickness direction is 6.5%, for example, And a slit having a thickness of 0.2 mm and a width of 15 mm are prepared. This prepared silicon steel sheet 1
1 is wound, for example, 32 times by a generally known method, as shown in step S2 of FIG.
To form At this time, the winding body 12 has an inner diameter of, for example, 23 mm and an outer diameter of 36 mm.

The silicon steel plate 11 has magnetic properties as shown in III of FIG. 3. The residual magnetic flux density Br is as low as about 0.05 Tesla [T]. The rise of the initial characteristics of the density B (curve C shown in FIG. 3) is also gentle. In this case, the ratio of the residual magnetic flux density (Br) to the saturated magnetic flux density (Bs) (residual magnetic flux density / saturated magnetic flux density = Br / Bs) is 0.03. As a result, the above-mentioned wound body 12 is directly
Even when an inductor is used, the permeability μ shows a substantially uniform value until the current flowing through the coil 5 becomes considerably large, and as shown by the curve c in FIG. (Superimposed current) is a considerably large value, specifically, the inductance is substantially uniform up to 13A.
In addition, the inductor has twice the inductance of the inductor shown in the prior art. Since the magnetic permeability μ is uniform and the inductance is uniform in such a wide current range, even if this wound body 12 is used as the wound core 1 as it is, it can be used as a choke coil without any problem. It is.

The reasons for the low residual magnetic flux density and low initial characteristics of the silicon steel plate 11 are presumed to be as follows. That is, since the silicon steel plate 11 is a graded material in which the silicon concentration is increased from the center to the surface in the thickness direction, the magnetostriction between the center layer and the surface layer is caused by the difference in components between the center layer and the surface layer. Since the constants are different, it is estimated that the tension is different.

Next, as shown in step S3 of FIG.
The wound core 1 composed of the wound body 12 as it is is housed in the main body 3. Next, as shown in step S4 of FIG.
The end faces of the inner wall and the outer wall are adhered to the end faces of the inner wall and the outer wall of the main body 3, and the wound core 1 is housed in the insulator 2 formed by the main body 3 and the lid 4 for protection. Next, an enamel wire is wound around the insulator 2, for example, 26 times to form the coil 5. Each of both ends of the coil 5 becomes a drawer 6,
For example, if it is used for absorbing noise in a power supply line, the lead section 6 is connected to the power supply line.

In the inductor configured as described above, the magnetic permeability μ does not decrease rapidly even when the current flowing through the coil increases, and the magnetic permeability tends to gradually decrease over a wide range of current. Has become. Therefore, as shown by the curve c in FIG. 4, an inductance that tends to gradually decrease with respect to a wide range of current (DC superimposed current) is obtained, and can be used as a choke coil.

Next, a method for producing the above-mentioned silicon steel sheet in which the silicon concentration of the central layer in the thickness direction is 3.5% and the silicon concentration of the surface layer in the thickness direction is 6.5% will be described. First, a grain-oriented silicon steel sheet having a silicon concentration of 3.0% is rolled to a thickness of 0.2 mm. This 0.2 mm thick silicon steel sheet is
Heat in an atmosphere of 0 ° C for several hours or more. Thereafter, it contains silicon tetrachloride (SiCl 4) and is subjected to chemical vapor deposition (CVD, Chemic
The silicon is penetrated from both surfaces of the silicon steel sheet by an alVapor deposition method. Next, for example, heating is performed for several tens of seconds to several tens of minutes in an atmosphere of 1200 ° C. to diffuse the silicon permeated from both surfaces to the center, and then naturally cooled. Thus, the silicon concentration of the central layer in the thickness direction is 3.
A silicon steel sheet having a thickness of 0.2 mm and a silicon concentration of 0% and a silicon concentration of the surface layer of 6.5% in the thickness direction was obtained.

In the inductor configured as described above, the silicon concentration of the central layer in the thickness direction is 3.0%.
And the silicon concentration of the surface layer in the thickness direction is 6.5.
Just by winding a predetermined number of turns of silicon steel plate,
Because the winding core can be configured, the manufacturing of the winding core is easy,
As a result, there is an effect that the manufacture of the inductor becomes easy.

In the first embodiment described above,
Although the thickness of the silicon steel plate 11 was set to 0.2 mm, the thickness is not limited to 0.1 mm and 0.05 mm.
The width, length, and number of turns for forming the wound core 1 may be appropriately selected according to the desired inductance of the inductor.

In the first embodiment,
As the silicon steel sheet 11, a silicon steel sheet having a silicon concentration of 3.0% in the central layer in the thickness direction and a silicon concentration of 6.5% in the surface layer in the thickness direction was used. Thus, a silicon steel sheet having a high silicon concentration on the surface has the same effect. However, in order to obtain a silicon steel sheet having a desired thickness, for example, 0.2 mm or less, it is necessary to reduce the thickness by rolling, and a certain degree of viscosity is required as a silicon steel sheet. It is preferable to use 0% silicon steel sheet. Preferably, the silicon concentration in the central layer is between 2.5 and 3.5.
%. In addition, since it is necessary to make the residual magnetic flux density as a silicon steel sheet a very low value, it is necessary to increase the silicon concentration of the surface layer. There is a risk of being cut when wound around. As a result of various experiments, the silicon steel plate 11 can be wound without being cut to form the wound iron core 1, and in order to have the desired remanent magnetic properties as the wound iron core 1 used as an inductor, the silicon of the surface layer must be formed. A concentration of 6.5% has been found to be optimal. Preferably, the silicon concentration of the surface layer may be 6.0 to 7.0%.

Further, in the first embodiment, the silicon concentration in the central layer in the thickness direction is 3.0%, the silicon concentration in the surface layer in the thickness direction is 6.5%,
Although the inductor was configured using a silicon steel sheet having a residual magnetic flux density of 0.05 to 0.1 T, the present invention is not limited to this. When steel sheets having various residual magnetic flux densities were manufactured and the inductor was manufactured, An inductor using a steel sheet having a ratio of the residual magnetic flux density (Br) to the saturated magnetic flux density (Bs) (residual magnetic flux density / saturated magnetic flux density = Br / Bs) is equal to or less than 0.35. (1) heat treatment of the wound body as described in the prior art,
(2) Impregnating the wound body with a resin, (3) providing a gap in the wound body, and (4) loading a resin body in the gap of the wound body without requiring a desired choke coil. Characteristics were obtained.

Further, in the first embodiment,
Although the case where the wound core 1 is protected by the insulator 2 which is a case composed of the main body 3 and the lid 4 is shown, the present invention is not limited to this. The insulator 2 for protecting the wound core 1 may be directly coated by fluid coating to form the insulator 2, or the insulator 2 for protecting the wound core 1 may be formed by directly dipping and coating a liquid resin.
It may be.

[Brief description of the drawings]

FIG. 1 is a diagram showing a method for manufacturing an inductor according to a first embodiment of the present invention in the order of manufacturing steps.

FIG. 2 is a diagram showing a method of manufacturing the inductor according to the first embodiment of the present invention in the order of manufacturing steps.

FIG. 3 is a diagram showing magnetic properties of a silicon steel sheet according to the first embodiment of the present invention and a conventional example.

FIG. 4 is a diagram showing a relationship between a DC superimposed current and an inductance in the first embodiment of the present invention and a conventional example.

FIG. 5 is a diagram showing a conventional method for manufacturing an inductor in the order of manufacturing steps.

FIG. 6 is a diagram showing a conventional method for manufacturing an inductor in the order of manufacturing steps.

FIG. 7 is a diagram showing magnetic properties of a silicon steel plate in a conventional inductor.

[Explanation of symbols]

 1 core, 2 insulators, 5 coils.

Claims (4)

[Claims] 1. A wound iron core formed by winding a steel sheet having a ratio of residual magnetic flux density to saturated magnetic flux density (residual magnetic flux density / saturated magnetic flux density) of 0.35 or less, an insulation for protecting the wound iron core. Body, an inductor with a coil wound around this insulator. 2. A wound iron core formed by winding a silicon steel sheet having a high silicon concentration a plurality of times from the center to the surface in the thickness direction, an insulator protecting the wound iron core, and a coil wound around the insulator. Equipped inductor. 3. A plurality of silicon steel sheets having a silicon concentration in the central layer in the thickness direction of 2.5 to 3.5% and a silicon concentration in the surface layer in the thickness direction of 6.0 to 7.0%. An inductor including a wound core formed by winding, an insulator protecting the wound core, and a coil wound around the insulator. 4. The silicon steel sheet in the above-mentioned wound iron core is characterized in that the silicon concentration in the central layer in the thickness direction is 3.0% and the silicon concentration in the surface layer in the thickness direction is 6.5%. The inductor according to claim 3.