JPH1140426A - Inductance device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inductance device by which a high inductance can be obtained under a large amount of current and the connection resistance to a pattern conductor can be reduced. SOLUTION: A first magnetic core 1 and a second magnetic core 2 exhibiting different magnetic properties are assembled with surface contact between at least one face of each. The first magnetic core 1 has at least one groove 11 on its contact face. The groove 11 is open at both sides of the magnetic core. A conductor 3 is placed inside the groove 11 and its major part is surrounded by the first and second magnetic cores 1 and 2. Ends of the conductor 3 which are led out of the groove 11 are provided with terminals 301 and 302 for connection to outside. The terminals 301 and 302 have a width W2 larger than a width W 1 of a major part 300.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inductance element, and more particularly, to a power transmission circuit operating at high frequency,
For example, the present invention relates to an inductance element suitable for use as a choke coil or a transformer in a switching power supply.

[0002]

2. Description of the Related Art A high-frequency switching power supply having a high operating frequency is used as an electronic circuit of information equipment, communication equipment, measuring equipment and the like, an electronic circuit of a manufacturing apparatus such as a machine tool, and a power supply used for mechanical driving. It has become. In a high-frequency switching power supply, an AC waveform such as a pulse is converted into a DC waveform to obtain a stabilized DC output. Generally, an LC filter is used as a means for converting AC to DC. Ferrite magnetic material, as a magnetic material for the magnetic core of the inductance element constituting the LC filter,
Crystalline metallic magnetic materials such as permalloy and amorphous materials are known. Among them, the inductance element made of crystalline metal magnetic material and amorphous material,
It has excellent DC superimposition characteristics, but is inferior to ferrite in iron loss characteristics. For this reason, a ferrite magnetic material is mainly used as a magnetic core material of this kind of inductance element.

[0003] By the way, computers, such as portable ones, are becoming smaller, thinner and lighter, but on the other hand, there is a strong market need for higher speeds and higher functions, and the circuit scale becomes larger and larger currents are required. There is a tendency. Therefore, a low-loss inductance element that is small and thin and that can be used even in a large current region is required.

[0004] Conventionally, as this kind of inductance element, two types, a gapless type using a core having a completely closed magnetic circuit structure without a gap and a gap type having a gap in a part of the magnetic core, are mainly used. .

However, when there is no gap, in an application to a high-frequency switching power supply in which DC superposition is applied,
There is a problem that magnetic saturation easily occurs.

In the case of an inductance element with a gap, the magnetic field strength that causes magnetic saturation is high, and even when subjected to DC superposition, it is possible to avoid magnetic saturation of the magnetic core, but the magnetic permeability μ becomes low. There is a problem that the inductance becomes small.

In addition, in the case of an inductance element with a gap, it is necessary to adjust the size of the gap in accordance with the magnitude of the current to be used. However, there is a drawback in that productivity becomes low, such as complexity and processing cost.

As one example of a gap inductor, a structure called a spacer gap in which a nonmagnetic material is inserted between a pair of ferrite cut cores is also known. In this type of inductance element, it is not necessary to cut the ferrite cut core, which is convenient in terms of productivity. However, the gap portion into which the non-magnetic material is inserted forms an open magnetic path, which causes noise interference due to magnetic flux leakage.

The winding portion is generally formed by winding a conductor with a coating such as a urethane wire around a bobbin. In the case of such a configuration, since the structure is complicated, there are many dead spaces that are not actually used for the winding, and there arises a problem that the magnetic path length becomes long and a sufficient winding space cannot be obtained. As the magnetic path length increases, the inductance decreases in inverse proportion. If the winding space is not sufficient, the winding impedance cannot be sufficiently reduced, and the copper loss increases. Moreover, as described above, when the inductance is reduced due to the addition of the gap and the increase in the magnetic path length,
A larger number of windings is required, which synergistically increases copper losses and is a major obstacle to miniaturization.

[0010] As described above, the inductance element is
It is necessary to solve various problems in order to use it in a power transmission circuit of a switching power supply that operates at a high frequency, and conventionally known inductance elements are not sufficient as means for solving these problems. Japanese Patent Application Laid-Open No. Hei 7-288210 discloses an inductor using two types of ferrite cores, but does not disclose the means for solving the above-mentioned problem.

[0011]

An object of the present invention is to provide an inductance element capable of obtaining a high inductance under a large current.

Another object of the present invention is to provide a small and thin inductance element.

Still another object of the present invention is to provide an inductance element capable of obtaining a high inductance under a large current.

Still another object of the present invention is to provide an inductance element which can be mounted on a substrate with a small resistance, despite being miniaturized.

Still another object of the present invention is to provide an inductance element which has high productivity and can contribute to cost reduction.

[0016]

In order to solve the above-mentioned problems, an inductance element according to the present invention includes a first magnetic core, a second magnetic core, and at least one conductor.

The first magnetic core and the second magnetic core are different from each other in magnetic characteristics, and at least one surface is combined in surface contact with each other. At least one of the first magnetic core and the second magnetic core has at least one groove on a contact surface, and the groove has both ends open on the side surfaces of the magnetic core.

The conductor includes a main part and a terminal part.
The main portion is disposed inside the groove, surrounded by the first magnetic core and the second magnetic core, and both ends are led out of the groove. The terminal portions are provided at both ends of the main portion, and have a width wider than a width of the main portion.

As described above, in the inductance element according to the present invention, since the first magnetic core and the second magnetic core have different magnetic characteristics, an inductance element that complements the other magnetic characteristics can be obtained. For example, the first
Using a ferrite core with high magnetic permeability μ and low iron loss at high frequency for the magnetic core, and using a metal core with excellent DC superposition characteristics for the second core, magnetic permeability μ, high frequency loss and DC superposition characteristics Can be obtained.

At least one of the first magnetic core and the second magnetic core has at least one groove in the contact surface, and the conductor is disposed inside the groove, so that the sectional area of the conductor is reduced to the sectional area of the groove. It can be enlarged to a corresponding size, and copper loss of the conductor can be reduced.

The first magnetic core and the second magnetic core are combined with at least one surface being in surface contact with each other, and the main part of the conductor is arranged inside the groove and is surrounded by the composite magnetic core, so that the shortest is possible. The magnetic path length can be configured, and a high inductance value can be obtained.

Moreover, since the first magnetic core and the second magnetic core are combined with at least one surface being in surface contact with each other, the magnetic circuit has a closed magnetic circuit configuration, and noise disturbance due to leakage magnetic flux can be avoided. . Further, since a substantial magnetic gap does not occur between the first magnetic core and the second magnetic core, it is possible to avoid a decrease in the magnetic permeability μ due to the magnetic gap.

Since the conductor has terminal portions that can be connected to the outside at both ends led out of the groove, through the terminal portion,
A variety of circuit configurations such as a series circuit, a parallel circuit, or a combination thereof can be realized by connecting to an external circuit and using a plurality of inductance elements and selecting connection of the terminals.

Further, the terminal portion has a width wider than the width of the main portion. According to this configuration, the connection area between the terminal portion and the connection portion of the pattern conductor can be increased. For this reason,
The resistance at the connection portion of the pattern conductor can be reduced.

Further, the main portion has a different width from the terminal portion. Therefore, the cross-sectional area and the cross-sectional shape of the main part can be set to the dimensions required for the main part independently of the terminal part. For example, it is possible to select a cross-sectional shape suitable for obtaining a high inductance value while securing a cross-sectional area necessary for reducing copper loss in a main part.

Further, in the present invention, since the conductor formed in advance by a mold or etching is merely fitted into the groove,
No winding is required, and the assembly work is extremely simple.
Moreover, since no bobbin is used and there is no need to provide a gap, cutting is not required. Therefore, the manufacturing cost can be reduced, standardization is facilitated, and productivity is improved.
When multiple inductance cells are configured,
Since the individual inductance cells can be used independently, they can be arbitrarily connected in series or in parallel, thereby expanding the range of application.

[0027] Another inductance element according to the present invention for solving the above-described problem includes a first magnetic core, a second magnetic core, and a plurality of conductors.

The first magnetic core and the second magnetic core are different from each other in magnetic characteristics, and at least one surface is combined in surface contact with each other. At least one of the first magnetic core and the second magnetic core has at least one groove on a contact surface, and the groove has both ends open on the side surfaces of the magnetic core.

Each of the conductors includes a main part and a terminal part. The main portion is disposed inside the groove at a distance, is surrounded by the first magnetic core and the second magnetic core, and both ends are led out of the groove. The terminal portions are provided at both ends of the main portion and can be connected to the outside, and an arrangement pitch is wider than an arrangement pitch between the main portions.

As described above, in the inductance element according to the present invention, since the first magnetic core and the second magnetic core have different magnetic characteristics, an inductance element that complements the other magnetic characteristics can be obtained.

The first magnetic core and the second magnetic core are combined with at least one surface being in surface contact with each other, and the main portion of the conductor is disposed inside the groove and is surrounded by the composite magnetic core, so that the shortest is possible. The magnetic path length can be configured, and a high inductance value can be obtained.

In addition, since the first magnetic core and the second magnetic core are combined with at least one surface being in surface contact with each other, the magnetic circuit has a closed magnetic circuit configuration, and noise disturbance due to leakage magnetic flux can be avoided. . Further, since a substantial magnetic gap does not occur between the first magnetic core and the second magnetic core, it is possible to avoid a decrease in the magnetic permeability μ due to the magnetic gap.

Since the conductor has terminal portions that can be connected to the outside at both ends led out of the groove, through the terminal portion,
A variety of circuit configurations such as a series circuit, a parallel circuit, or a combination thereof can be realized by connecting to an external circuit and using a plurality of inductance elements and selecting connection of the terminals.

Further, the arrangement pitch of the terminal portions is wider than the arrangement pitch between the main portions. According to this configuration, the area of the connection portion connected to the terminal portion in the pattern conductor portion can be increased. For this reason, the resistance at the connection portion of the pattern conductor can be reduced.

In addition, the arrangement pitch of the main parts is different from the arrangement pitch between the terminal parts. Therefore, the arrangement pitch of the main part, and the cross-sectional area and the cross-sectional shape of the main part can be set to the dimensions required for the main part independently of the terminal part. For example, an arrangement pitch and a cross-sectional shape suitable for obtaining a high inductance value can be selected while securing a cross-sectional area necessary for reducing copper loss in a main part.

Also, since the arrangement pitch between the terminals is wide,
When mounting the inductance element according to the present invention on a substrate, using a substrate having a wide arrangement pitch between pattern conductors,
A plurality of terminal portions can be easily connected to the connection portion.

Therefore, the inductance element according to the present invention can be mounted on a substrate with a small resistance.

Furthermore, since a plurality of conductors formed in advance by a mold or etching are merely fitted into the grooves, no winding is required and the assembling operation is very simple. Moreover, since no bobbin is used and no gap is required, cutting is not required. Therefore, production costs can be reduced, standardization can be facilitated, and productivity can be improved. When a plurality of inductance cells are formed, the individual inductance cells can be used independently, so that they can be arbitrarily connected in series or in parallel, thereby expanding the application range.

Other objects, configurations and advantages of the present invention will be described in more detail with reference to the accompanying drawings which are embodiments.

[0040]

1 is a plan view of an inductance element according to the present invention, FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, and FIG. 3 is a sectional view of the inductance element shown in FIGS. It is an exploded perspective view.

As shown, the inductance element according to the present invention includes a first magnetic core 1, a second magnetic core 2, and at least one conductor 3. The first magnetic core 1 and the second magnetic core 2 are different from each other in magnetic properties, and at least one surface is combined in surface contact with each other. Among the first magnetic core and the second magnetic core 2, the first magnetic core 1 has at least one groove 11 on the contact surface. Both ends of the groove 11 are open on the side surfaces of the magnetic core.

The conductor 3 includes a main part 300 and a terminal part 30.
1, 302. The main part 300 is arranged inside the groove 11, and both ends are led out of the groove 11. The terminal portions 301 and 302 can be connected to the outside, are provided at both ends of the main portion 300, and have a width W2 wider than the width W1 of the main portion 300.

The first magnetic core 1 is made of a magnetic material having a high magnetic permeability μ and a small iron loss at a high frequency, for example, ferrite. The second magnetic core 2 has a magnetic permeability μ lower than that of the first magnetic core 1, but has a higher saturation magnetic flux density Bs than that of the first magnetic core 1, and is a magnetic material such as metal Use the magnetic material of the system.

When the first magnetic core 1 is made of a ferrite magnetic material or the like, a mold forming step can be employed, and at this time, the grooves 11 can be formed simultaneously.

The conductor 3 is desirably formed using a low-impedance metal material such as a copper plate in order to reduce copper loss. The groove 11 is designed to have a minimum necessary size for installing the conductor 3. The conductor 3 can be provided with an electric insulating means for insulating the first magnetic core 1 or the second magnetic core 2 from each other.

FIG. 4 is an electrical equivalent circuit diagram of the inductance element shown in FIGS.
An inductance L is obtained between the terminal portion 302 and the terminal portion 302.

As described above, in the inductance element according to the present invention, the first magnetic core 1 and the second magnetic core 2
Since the magnetic characteristics are different from each other, an inductance element that complements the other magnetic characteristics can be obtained. For example, a ferrite magnetic material having a high magnetic permeability μ and a small iron loss at a high frequency is used for the first magnetic core 1, and a metal-based magnetic material having excellent DC bias characteristics is used for the second magnetic core 2. An inductance element having a high μ, a small high-frequency loss, and excellent DC bias characteristics can be obtained.

The above-mentioned advantages of the present invention will be described in more detail in comparison with a conventional magnetic core structure. FIG. 30 is a sectional view of a conventional inductance element using a ferrite core called a cut core. In FIG. 30, two ferrite cores 40 and 41 having substantially the same cross section E are combined from above and below, and a coil 42 is wound around a central leg. The coil 42 is usually a bobbin 4 made of an insulating resin.
It is wound on three. In the conventional example shown in FIG. 30, the ferrite cores 40 and 41 are closely attached and combined to form a magnetic circuit without a gap.

FIG. 31 is a diagram showing another conventional example of an inductance element. In this conventional example, a gap 44 forming a gap is provided in the middle leg.

FIG. 32 is a view showing still another conventional example of an inductance element. A non-magnetic insulator 44 forming a gap is inserted between the ferrite cores 40 and 41. Such a structure is called a spacer gap. In any of the conventional examples shown in FIGS. 30 to 32, the coil 42 generally uses a film-coated lead such as a urethane wire.

FIG. 33 shows a broken line approximation BH curve with the magnetic field strength H on the horizontal axis and the magnetic flux density B on the vertical axis.
From the relationship of μH, the slope of the curve represents the magnetic permeability μ. The inductance L of the inductance element is proportional to the magnetic permeability μ.
Bs is the saturation magnetic flux density, and when it exceeds this value, the magnetic permeability μ decreases sharply and reaches a saturated state.

The intensity of the magnetic field on the horizontal axis is represented by H = NI / Le. Here, N represents the number of windings, I represents a current, and Le represents a magnetic path length. That is, the strength of the magnetic field is proportional to the flowing current.

A curve a in FIG. 33 is a BH curve showing a general characteristic tendency of the inductance element having "no gap" shown in FIG. As shown by the curve a, when there is no gap, when the magnetic field strength is equal to or less than the magnetic field strength H1, the magnetic permeability μ
And a high inductance can be obtained. However, since the magnetic field strength H1 that causes magnetic saturation is small, even a slight DC superposition is applied, and the magnetic field strength exceeds the magnetic field strength H1 to reach a saturation region. Therefore, this type of inductance element is not suitable for an application in which direct current is superimposed, for example, an LC filter of a switching power supply.

A curve b in FIG. 33 is a BH curve showing a general characteristic tendency of the inductance element having "gap" shown in FIG. 30 or 31. Ferrite core 40,
When a gap is provided in 41, as shown by a curve b in FIG.
The magnetic field strength causing magnetic saturation is improved to the point of the magnetic field strength H2 which is larger than the magnetic field strength H1 in the case of the curve a. However, the slope of the BH curve becomes gentle, the magnetic permeability μ decreases, and the inductance decreases. As described above, when the gap is provided to increase the magnetic field intensity that causes magnetic saturation and to improve the DC superimposition characteristics, the inductance is reduced, so that the conventional general magnetic core structure improves the DC superposition characteristics. However, it was very difficult to obtain a large inductance.

On the other hand, in the present invention, the first magnetic core 1 and the second magnetic core 2 having different magnetic characteristics are used together to realize a combination of characteristics suitable for mutual complementation, and An inductance element having excellent characteristics and a large inductance can be obtained.

Further, in the present invention, the shortest magnetic path length can be formed by surrounding the conductor 3 with the first magnetic core 1 and the second magnetic core 2, and high inductance characteristics can be obtained. FIG.
In the case of the conventional structure illustrated in FIGS.
There is a problem that a dead space not actually used for the winding increases, a magnetic path length increases, and a sufficient winding space cannot be obtained. The inductance L of the inductance element is represented by L = N ² μS / Le. Where N is the number of turns, S is the cross-sectional area of the magnetic core, Le
Is the magnetic path length of the magnetic core. As shown in this equation, the magnetic path length Le
Becomes longer, the inductance L decreases in inverse proportion.

If the winding space is not sufficient, the impedance of the winding cannot be reduced sufficiently.
Copper loss increases. In addition, if the inductance is reduced due to the addition of a gap and the magnetic path length is increased, a larger number of windings is required, and the copper loss increases synergistically, which is a major obstacle to miniaturization.

On the other hand, in the case of the present invention, as described above, the shortest magnetic path length can be formed, and high inductance characteristics can be obtained. For this reason, when the inductance element according to the present invention is used for an LC filter or the like of a high-frequency switching power supply, the ripple voltage can be reduced.

Further, in the present invention, since the first magnetic core 1 has the groove 11 on the contact surface and the conductor 3 is disposed inside the groove 11, the sectional area of the conductor 3 corresponds to the sectional area of the groove 11. Thus, the copper loss of the conductor 3 can be reduced.

In addition, the first magnetic core 1 and the second magnetic core 2
Since at least one surface is combined in surface contact with each other, the magnetic circuit has a closed magnetic circuit configuration, and noise interference due to leakage magnetic flux can be reliably avoided. Further, since a substantial magnetic gap does not occur in the first magnetic core 1 and the second magnetic core 2, a decrease in the magnetic permeability μ due to the magnetic gap can be avoided.

The magnetic core surrounding the conductor 3 does not need to be limited to the two types of the first magnetic core 1 and the second magnetic core 2, but may be composed of more magnetic cores to improve the performance.

In the present invention, since the conductor 3 has the terminal portions 301 and 302 which can be connected to the outside, the conductor 3 can be connected to an external circuit through the terminal portions 301 and 302 and a plurality of inductance elements are used. Part 3
Various circuit configurations such as a series circuit, a parallel circuit, or a combination thereof can be realized by selecting the connection of 01 and 302.

Further, the terminal portions 301 and 302 have a width W2 wider than the width W1 of the main portion 300. Usually, the pattern conductor has a very small standard thickness of 35 μm.
Therefore, the resistance of the connection part of the pattern conductor tends to increase when the terminal part is connected. In the present invention, since the terminal portions 301 and 302 have a width W2 wider than the width W1 of the main portion 300, the connection area between the terminal portions 301 and 302 and the connection portion of the pattern conductor can be increased. For this reason, the resistance at the connection portion of the pattern conductor can be reduced. This point will be further described with reference to FIG.

FIG. 5 is a plan view showing a state where the inductance element shown in FIGS. 1 to 3 is mounted on a circuit board.
In the embodiment shown in FIG. 5, the terminal portions 301 and 302 are connected and fixed to the pattern conductors 81 and 82 formed on the circuit board 7 by means such as solder. In the present invention, since the terminal portions 301 and 302 have a width W2 wider than the width W1 of the main portion 300, the connection area of the connection portion between the terminal portions 301 and 302 and the pattern conductors 81 and 82 can be increased. Therefore, the resistance at the connection portion between the pattern conductors 81 and 82 can be reduced.

The width W2 of the terminal portions 301 and 302 is
As described above, the width can be increased within the width W0 of the inductance element. As shown in FIG. 5, if the width W2 of the terminal portions 301 and 302 is set within the width W0 of the inductance element, the mounting density on the circuit board 7 does not decrease.

Further, the main part 300 is composed of the terminal parts 301, 3
02 has a width W1 different from the width W2. Therefore, the main part 3
00 and the terminal portions 301 and 302
Independent of the dimensions, the dimensions required for the main part 300 can be set. For example, in the main portion 300, a cross-sectional shape suitable for obtaining a high inductance value can be selected while securing a cross-sectional area necessary for reducing copper loss.

In the present invention, since the conductor 3 formed in advance by a mold or etching is merely fitted into the groove 11,
No winding is required, and the assembly work is extremely simple.
Moreover, since no bobbin is used and no gap is required, cutting is not required. Therefore, production costs can be reduced, standardization is facilitated, and production problems can be solved. When a plurality of inductance cells are formed, the individual inductance cells can be used independently, so that they can be arbitrarily connected in series or in parallel, thereby expanding the application range.

FIG. 6 shows an LC filter circuit using the inductance element according to the present invention shown in FIGS. 1 to 4, and FIG. 7 shows a waveform when a DC output voltage Eo is obtained by inputting a pulse voltage Ein in FIG. FIG. ΔEo indicates the ripple voltage included in the DC output voltage Eo, T is the cycle, and τ is the ON time of the pulse voltage. Capacitor C1
Is Zc and the inductance of the inductance element is L, the ripple voltage ΔEo is represented by ΔEo = Eo · (T−τ) · Zc / L. According to this equation, since the ripple voltage ΔEo is inversely proportional to the inductance L, the ripple voltage ΔEo
Must be increased to reduce the inductance L. According to the present invention, as described above, since a high inductance is obtained, the ripple voltage ΔEo can be reduced. When the inductance L is small, it is necessary to increase the operating frequency in order to reduce the ripple voltage ΔEo, which involves a decrease in efficiency, an increase in noise, and an increase in component costs.

FIG. 8 is a plan view showing another embodiment of the inductance element according to the present invention, and FIG. 9 is a sectional view taken along line 9-9 in FIG. This embodiment has a structure in which a first magnetic core 1 and a second magnetic core 2 are joined by a tape 10. In addition, you may tighten using a metal band etc.

FIG. 10 shows a plurality of n inductance elements 6.
FIG. 1 shows an example in which 1 to 6n are connected in parallel on a circuit board 7.
1 shows an electrical equivalent circuit diagram thereof. In the embodiment shown in FIG.
1 to 6n are arranged on the circuit board 7, and the terminal portions 301 and 302 of the inductance element are connected and fixed to the pattern conductors 81 and 82 formed on the circuit board 7 by means such as soldering. Thereby, as shown in FIG. 11, a circuit configuration in which the inductance elements 61 to 6n are connected in parallel is obtained.

FIG. 12 shows an example in which a plurality of n = 3 inductance elements 61, 62 and 63 are connected in series on the circuit board 7, and FIG. 13 shows an electrical equivalent circuit diagram thereof. In the embodiment shown in FIG. 12, the pattern conductors 81 to 84 formed on the circuit board 7 are
The n terminal portions 301 and 302 are connected and fixed by means such as soldering. As a result, a circuit configuration in which the inductance elements 61 to 6n are connected in series is obtained as shown in FIG. Although illustration is omitted, even a series-parallel connection can be easily realized.

FIG. 14 is a plan view showing another embodiment of the inductance element according to the present invention, FIG. 15 is a partially enlarged perspective view of the inductance element shown in FIG. 14, and FIG. 16 is shown in FIGS. It is an electric equivalent circuit diagram of an inductance element. In this embodiment, a plurality of conductors 31, 32, 33 are provided in a groove 11 provided in the first magnetic core 1.
The insulating resin 9 is filled around the conductors 31 to 33 in the groove 11 (see FIG. 15). The number of conductors 31 to 33 can be set arbitrarily according to the application.

Each of the conductors 31 to 33 is
0 and terminal portions 301 and 302. The main part is groove 1
1, are arranged with arrangement pitches P11 and P12, are surrounded by a first magnetic core 1 and a second magnetic core 2,
Both ends are led out of the groove 11. Terminal section 301,
302 are provided at both ends of the main part 300 and can be connected to the outside. The arrangement pitches P21 and P22 of the terminal portions 301 and 302 are wider than the arrangement pitches P11 and P12 between the main portions 300 and 300.

In the inductance element shown in FIGS. 14 to 16, the first magnetic core 1 and the second magnetic core 2 have different magnetic characteristics, so that an inductance element complementary to other magnetic characteristics can be obtained. . For example, a ferrite core having a high magnetic permeability μ and a small iron loss at high frequencies is used for the first magnetic core 1, and a metal core having excellent DC superposition characteristics is used for the second magnetic core 2. An inductance element having excellent loss and DC superposition characteristics can be obtained.

At least one surface of the first magnetic core 1 and the second magnetic core 2 are combined in surface contact with each other, and the main parts of the conductors 31 to 33 are arranged inside the groove 11 and are surrounded by the composite magnetic core. Therefore, the shortest magnetic path length can be formed, and a high inductance value can be obtained.

Moreover, the first magnetic core 1 and the second magnetic core 2
Since at least one surface is combined in surface contact with each other, the magnetic circuit has a closed magnetic circuit configuration, and noise interference due to leakage magnetic flux can be avoided. Further, since a substantial magnetic gap does not occur between the first magnetic core 1 and the second magnetic core 2, it is possible to avoid a decrease in the magnetic permeability μ due to the magnetic gap.

The conductors 31 to 33 have terminal portions 301 and 302 which can be connected to the outside at both ends led out of the groove 11, so that the conductors 31 to 33 can be connected to an external circuit through the terminal portions 301 and 302 and have a plurality of inductances. Various circuit configurations such as a series circuit, a parallel circuit, or a combination thereof can be realized by using an element and selecting connection of the terminal portions 301 and 302.

Further, the arrangement pitches P21 and P22 of the terminal portions 301 and 302 are wider than the arrangement pitches P11 and P12 between the main portions 300 and 300. Usually, the pattern conductors 31 to 33 have a very small standard thickness of 35 μm.
Therefore, the connection portions of the pattern conductors 31 to 33 tend to have a large resistance when the terminal portions 301 and 302 are connected. In the present invention, the terminal portions 301 and 302
Since the arrangement pitches P21 and P22 are wider than the arrangement pitches P11 and P12 between the main parts 300 and 300, the area of the connection part connected to the terminal parts 301 and 302 in the pattern conductors 31 to 33 can be increased. For this reason, the resistance at the connection portions of the pattern conductors 31 to 33 can be reduced.

Further, between the terminal portions 301 and 301, and
Since the arrangement pitches P21 and P22 between the terminal portions 302 and 302 are wide, when mounting the inductance element according to the present invention on the substrate, a substrate having a wide arrangement pitch between the pattern conductors 31 to 33 is used to form a plurality of terminal portions. 301 and 302 can be easily connected to the connection portion.

Therefore, the inductance element according to the present invention can be mounted on a substrate with a small resistance.

Further, the main part 300 has the arrangement pitch P1
1, P12 are terminal portions 301-301, 302-302
It is different from the arrangement pitches P21 and P22 between them. For this reason,
The arrangement pitches P11 and P12 of the main part 300, and further, the cross-sectional area and the cross-sectional shape of the main part 300,
Independent of 302, it can be set to the dimensions required for main part 300. For example, in the main part 300, while securing a cross-sectional area necessary for reducing copper loss,
An arrangement pitch and a cross-sectional shape suitable for obtaining a high inductance value can be selected.

Further, since a plurality of conductors 31 to 33 formed in advance by a mold or etching are merely fitted into the grooves 11, no winding is required and the assembling work is very simple. Moreover, since no bobbin is used and no gap is required, cutting is not required. Therefore, production costs can be reduced, standardization can be facilitated, and productivity can be improved. When a plurality of inductance cells are formed, the individual inductance cells can be used independently, so that they can be arbitrarily connected in series or in parallel, thereby expanding the application range.

FIG. 17 is a plan view showing a state in which the inductance element shown in FIGS. 14 to 16 is mounted on the circuit board 7, and FIG. 18 is an electrical equivalent circuit diagram of FIG. Conductor 3
1 to 33 are connected by pattern conductors 83 and 84 so that current Io in the same direction flows. The pattern conductors 83 and 84 are led under the inductance element.

The number of turns by the conductors 31 to 33 is N (=
3), the sectional area of the magnetic cores 1 and 2 is S, and the magnetic path length by the magnetic cores 1 and 2 is Le. As described above, the inductance L is represented by L = N ² μS / Le. Therefore, by connecting the inductance elements shown in FIGS. 14 to 16 as shown in FIGS. 17 and 18, a large inductance can be obtained. Moreover, since the conductors 31 to 33 have a structure insulated from each other, they can be used not only as inductors but also as transformers.

FIG. 19 is a front view showing another embodiment of the inductance element according to the present invention. In this embodiment, a plurality of grooves 11, 1
2, 13 are provided, and conductors 31, 32, and 33 are arranged in the grooves 11, 12, and 13, respectively. Grooves 11, 12, 13
Are filled with insulating resins 91 to 93. According to this embodiment, the conductors 31, 32, 33 provided in the grooves 11, 12, 13 can constitute the inductance cells L1, L2, L3 having the shortest average magnetic path length. FIG.
The inductance element shown in FIG. 9 can be represented by the electrical equivalent circuit shown in FIG.

FIG. 21 is a plan view showing the inductance element shown in FIGS. 19 and 20 mounted on a circuit board 7, and FIG.
2 is an electric circuit diagram showing the circuit connection of FIG. Conductor 3
1 to 33 are pattern conductors 8 formed on the circuit board 7.
3, 84 in series, and conductors 31 to 3
3 form an inductance circuit in which inductances L1, L2, and L3 are connected in series. With this connection, an inductance element having an inductance (L1 + L2 + L3) obtained by adding the inductances L1, L2, and L3 can be formed.

FIG. 23 is a plan view of another example in which the inductance elements shown in FIGS. 19 and 20 are mounted on a printed circuit board 7, and FIG. 24 is an electric circuit diagram showing the circuit connection of FIG. The conductors 31 to 33 are connected in parallel by pattern conductors 81 and 82 formed on the circuit board 7. In this way, the inductance cell can be used alone, in series,
Because it can be used freely, such as in parallel, it can be used for many applications.

FIG. 25 is an exploded perspective view showing another embodiment of the inductance element according to the present invention, and FIG. 26 is a perspective view showing a partial assembly of the inductance element shown in FIG.
In this embodiment, the first magnetic core 1 has a plurality of grooves 11 to 11 on one surface.
The conductor 3 has the ends of the conductor pieces 31 to 35 inserted into the grooves 11 to 15, respectively.
7 form a continuous body. Horizontal frame 36, 3
7 is provided with terminal portions 301 and 302. The terminal portions 301 and 302 have a width W2 wider than the width W1 of the conductor pieces 31 to 35 constituting the main part. According to this embodiment, it is possible to obtain the above-described operation and effect obtained by increasing the width W2 of the terminal portions 301 and 302. The inductance element shown in this embodiment forms an equivalent circuit as shown in FIG.

FIG. 27 is an exploded perspective view showing another embodiment of the inductance element according to the present invention. In this embodiment, the first magnetic core 1 has a plurality of grooves 11 to 15 on one surface, and the conductor 3 includes conductor pieces 31 to 35 inserted in the grooves 11 to 15, respectively, in series. It is a connected continuum. Terminal portions 301 and 302 are provided at both ends of the continuum. The terminal portions 301 and 302 have a width W2 of
The width is wider than the width W1 of the conductor pieces 31 to 35 constituting the main part. The inductance element shown in this embodiment forms an equivalent circuit as shown in FIG.

FIG. 28 is a plan view showing another embodiment of the inductance element according to the present invention, and FIG. 29 is a partially enlarged perspective view of the inductance element shown in FIG. In the embodiment, the insulating resin 9 is provided around the conductors 31 to 33 in the groove 11.
(See FIG. 15). The number of conductors 31 to 33 can be set arbitrarily according to the application. Each of the conductors 31 to 33 includes a main part 300 and terminal parts 301 and 302. The main part 300 is arranged inside the groove 11 at a pitch P
11, P12, the first magnetic core 1 and the second
, And both ends are led out of the groove 11. The terminals 301 and 302 are provided at both ends of the main part 300 and can be connected to the outside. The terminal portions 301 and 302 have the arrangement pitches P21 and P22, and the conductor pieces 31 to 35 forming the main portion have the position pitches P11 and P22.
12 (see FIG. 29). Moreover, the terminal section 30
1, 302 are conductor pieces 3 whose width W2 is a main part.
The width is wider than the width W1 of 1 to 35 (see FIG. 28). The inductance element shown in this embodiment is the same as that shown in FIG.
The equivalent circuit shown in FIG.

In any of the embodiments shown in FIGS. 25 to 29, the above-described operation and effect can be obtained by widening the width W2 of the terminal portions 301 and 302. In addition, the conductor 3 previously formed by a mold, etching, or the like is connected to the first core 1.
The advantage is that the magnetic circuit can be simply and inexpensively constructed simply by fitting the magnetic circuit.

Although illustration is omitted, it goes without saying that there are many combinations of the embodiments.

[0093]

As described above, according to the present invention, the following effects can be obtained. (A) An inductance element capable of obtaining a high inductance under a large current can be provided. (B) It is possible to provide a small and thin inductance element. (C) An inductance element capable of obtaining a high inductance under a large current can be provided. (D) It is possible to provide an inductance element that can be mounted on a substrate with a small resistance, despite being miniaturized. (E) It is possible to provide an inductance element which has high productivity and can contribute to cost reduction.

[Brief description of the drawings]

FIG. 1 is a plan view of an inductance element according to the present invention.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is an exploded perspective view of the inductance element shown in FIGS. 1 and 2;

FIG. 4 is an electrical equivalent circuit diagram of the inductance element shown in FIGS.

FIG. 5 is a plan view showing a state where the inductance element shown in FIGS. 1 to 3 is mounted on a circuit board.

6 is an LC filter circuit diagram using the inductance element according to the present invention shown in FIGS.

FIG. 7 is a diagram showing a waveform when a pulse voltage is input and a DC output voltage is obtained in FIG. 6;

FIG. 8 is a plan view showing another embodiment of the inductance element according to the present invention.

FIG. 9 is a sectional view taken along line 9-9 in FIG. 8;

FIG. 10 is a diagram showing an embodiment in which a plurality of inductance elements are connected in parallel on a circuit board.

11 is an electrical equivalent circuit diagram of the embodiment shown in FIG.

FIG. 12 is a diagram showing an embodiment in which a plurality of inductance elements are connected on a circuit board.

FIG. 13 is an electrical equivalent circuit diagram of the embodiment shown in FIG.

FIG. 14 is a plan view showing another embodiment of the inductance element according to the present invention.

15 is a partially enlarged perspective view of the inductance element shown in FIG.

FIG. 16 is an electrical equivalent circuit diagram of the inductance element shown in FIGS. 14 and 15;

FIG. 17 is a plan view showing a state where the inductance element shown in FIGS. 14 and 15 is mounted on a printed circuit board.

18 is an electrical equivalent circuit diagram of FIG.

FIG. 19 is a partially enlarged perspective view showing another embodiment of the inductance element according to the present invention.

20 is an electrical equivalent circuit diagram of the inductance element shown in FIG.

FIG. 21 is a diagram showing a state in which the inductance capacitance element shown in FIGS. 19 and 20 is mounted on a circuit board.

FIG. 22 is an electrical equivalent circuit diagram of the embodiment shown in FIG.

FIG. 23 is a plan view showing another embodiment of the inductance element according to the present invention.

24 is an electrical equivalent circuit diagram of the inductance element shown in FIG.

FIG. 25 is an exploded perspective view showing another embodiment of the inductance element according to the present invention.

26 is a perspective view showing a partial assembly of the inductance element shown in FIG. 25.

FIG. 27 is an exploded perspective view showing another embodiment of the inductance element according to the present invention.

FIG. 28 is a plan view showing another embodiment of the inductance element according to the present invention.

FIG. 29 is a partially enlarged perspective view of the inductance element shown in FIG. 28;

FIG. 30 is a sectional view of a conventional inductance element.

FIG. 31 is a diagram showing another conventional example of an inductance element.

FIG. 32 is a view showing still another conventional example of an inductance element.

FIG. 33 is a diagram showing a BH curve approximated by a broken line.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st magnetic core 2 2nd magnetic core 3 Conductor 11 Groove 300 Main part 301,302 Terminal part 7 Circuit board

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Asako Kajita 1-1-13 Nihonbashi, Chuo-ku, Tokyo Inside TDK Corporation (72) Inventor Kazuyuki Ito 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDK Inside the corporation

Claims (11)

[Claims] 1. An inductor element including a first magnetic core, a second magnetic core, and at least one conductor, wherein the first magnetic core and the second magnetic core have different magnetic characteristics from each other, and at least At least one of the first magnetic core and the second magnetic core has at least one groove in a contact surface, and both ends of the groove are open at the side surfaces of the magnetic core. The conductor includes a main portion and a terminal portion, the main portion being disposed inside the groove, being surrounded by the first magnetic core and the second magnetic core, and both ends being outside the groove. Wherein the terminal portion can be connected to the outside, is provided at both ends of the main portion, and has a width wider than the width of the main portion. 2. The inductance element according to claim 1, wherein a plurality of the conductors are provided for one of the grooves. 3. The inductance element according to claim 1, wherein the groove includes a plurality of grooves, and the conductor has at least one groove for each of the grooves.
Inductance element provided. 4. The inductance element according to claim 3, wherein the conductor is connected to form a series circuit, a parallel circuit, or a combination thereof. 5. The inductance element according to claim 4, wherein the conductor is a continuum. 6. An inductor element including a first magnetic core, a second magnetic core, and a plurality of conductors, wherein the first magnetic core and the second magnetic core have different magnetic characteristics from each other, and have at least one surface. At least one of the first magnetic core and the second magnetic core has at least one groove on a contact surface, and the groove has both ends open at the magnetic core side surfaces. Each of the conductors includes a main part and a terminal part, wherein the main part is disposed at an interval inside the groove,
Being surrounded by the first core and the second core,
Both ends are led out of the groove, and the terminal portion can be connected to the outside, and is provided at both ends of the main portion, and the arrangement pitch is wider than the arrangement pitch between the main portions. . 7. The inductance element according to claim 6, wherein the terminal portion can be connected to the outside, is provided at both ends of the main portion, and has a width wider than a width of the main portion. Inductance element. 8. The inductance element according to claim 6, wherein a plurality of the conductors are provided for one of the grooves. 9. The inductance element according to claim 6, wherein a plurality of the grooves are provided, and the conductor has at least one groove for each of the grooves.
Inductance element provided. 10. The inductance element according to claim 6, wherein the conductor is connected to form a series circuit, a parallel circuit, or a combination thereof. 11. The inductance element according to claim 6, wherein the conductor is a continuum.