JP2002093642A - Inductance element, manufacturing method therefor and snubber circuit using the inductance element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inductance element, which is superior in the efficiency of winding work, in which winding work is automated and insulating property and inductance characteristics are improved. SOLUTION: The inductance element is provided with a coil, having a winding wire whose number of windings (N) in length 10 mm is 20 to 500 and having a hollow part, where both ends of the winding wire are opened and a core having the magnetic thin band of a single layer or plural layers, whose thickness is 4 μm to 50 μm and whose width is 2 mm to 40 mm and in which at least a part of the magnetic thin band is arranged in the hollow part. A ratio (N/n) of the number of windings (N) in the coil and the number of layers (n) in the magnetic thin band is 20 to 500. The outer part of the coil is covered by an insulator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an inductance element used for a snubber circuit or a delay element of a switching power supply, a method of manufacturing the same, and a snubber circuit using the inductance element.

[0002]

2. Description of the Related Art Inductance elements are used in various electric circuits. For example, in a switching power supply such as an RCC system, a MOS-F which is a switching element is used.
An inductance element (saturable inductor) is used as a current delay element that delays the gate signal of ET. This current delay element causes the snubber capacitor to function as a resonance capacitor and causes the MOS-FET to perform zero volt switching.

As a conventional inductance element, for example, an element having a toroidal core formed by winding or laminating a soft magnetic alloy ribbon is mainly used. When such an inductance element is applied to the current delay element as described above, a predetermined characteristic is obtained by winding a covered wire a plurality of times around a toroidal core having a closed magnetic circuit structure.

[0004] An inductance element having a toroidal core is advantageous in obtaining inductance based on its closed magnetic circuit structure. However, in the case of a toroidal core composed of a soft magnetic alloy ribbon, a wire is wound on an insulating bobbin in advance like a sintered core made of a ferrite sintered body, and the divided sintered cores are put together and closed. The configuration of forming a road cannot be easily applied.

[0005] From the above, when a toroidal core made of a conventional soft magnetic alloy ribbon is used,
It is common to form an inductance element by directly winding a toroidal core. However, with such a structure, the work efficiency of winding to the toroidal core is low, and it is difficult to automate the winding process. As a result, the manufacturing cost of the inductance device is increased.

In order to solve such problems, in recent years, in order to improve the work efficiency of the winding and to automate the winding, after winding the bobbin, a soft magnetic ribbon or the like is disposed in the bobbin. An inductance element having the following structure has been proposed.

[0007]

As described above, by forming a winding on the bobbin and then arranging the soft magnetic band in the bobbin, the working efficiency of the winding can be improved and the winding can be improved. Automation is becoming possible.

However, such an inductance element is required to avoid electrical contact between the winding and other parts, to improve the strength of the base of the lead terminal, to further improve the inductance characteristics, and the like.

An object of the present invention is to provide an inductance element and a method of manufacturing the same, which are capable of improving the inductance characteristics and solving the problems of electrical and strength.

Still another object of the present invention is to provide a snubber circuit having excellent characteristics and reliability by using such an inductance element.

[0011]

According to the inductance element of the present invention, the number of turns (N) per 10 mm length is 20 or more and 5 or more.
A coil having a hollow portion with both ends of the winding open, and a single-layer or multiple-layer magnetic ribbon having a thickness of 4 μm or more and 50 μm or less and a width of 2 mm or more and 40 mm or less, A core in which at least a part of the magnetic ribbon is disposed in the hollow portion, and a ratio (N / N) of the number of turns (N) of the coil to the number of layers (n) of the magnetic ribbon.
n) is not less than 20 and not more than 500, and at least an outer portion of the coil is covered with an insulator.

In the inductance element of the present invention, while the winding of the coil is formed into a cylindrical shape having both ends opened, the cross-sectional area of the magnetic ribbon constituting the core is extremely increased by sufficiently increasing the number of turns. Even if it is small, sufficient characteristics can be obtained.

In this case, the ratio (N / n) of the number of turns (N) of the coil to the number of layers (n) of the magnetic ribbon is used.
Is set to 20 or more and 500 or less, particularly good characteristics as a supersaturated inductor can be obtained.

In the inductance element of the present invention,
Unlike the conventional toroidal shape, a winding having open ends is used. Therefore, the working efficiency of the winding can be greatly improved as compared with the conventional toroidal inductance element. Specifically, the coil winding process can be easily automated. These make it possible to significantly reduce the manufacturing cost of the inductance element. Then, based on the N / n ratio described above,
Good inductance characteristics can be obtained.

According to the present invention, in the inductance element having the above-mentioned characteristics, at least a coil portion of the inductance element is covered with an insulator,
The insulation of the coil can be ensured, and the inductance characteristics can be improved.

By using, for example, a resin coating, a resin case, or a resin film as the insulator, the inductance element can be easily and reliably covered, and damage to the inductance element can be suppressed. This insulator is preferably provided with holes for improving heat dissipation. By providing a hole in the insulator, the heat dissipation of the inductance element can be improved.

The coil includes, for example, a cylindrical bobbin having a hollow portion, the winding is wound around an outer peripheral portion of the cylindrical bobbin, and the magnetic ribbon is provided inside the hollow portion of the cylindrical bobbin. That are inserted into the file. By adopting such a structure, the shape of the coil can be reliably maintained, and the coil can be easily manufactured.

Preferably, the cylindrical bobbin is provided with a lead terminal electrically connected to the winding. By providing such a lead terminal, it is possible to easily connect to a substrate or the like.

In such an inductance element using a bobbin having a lead terminal, the joint between the lead terminal and the bobbin or the base of the lead terminal is covered with an insulator to prevent the lead terminal from breaking or falling off. Becomes possible.

After the magnetic ribbon passes through the hollow portion, passes through the outside of the winding, and has a closed magnetic circuit structure penetrating the hollow portion again, so that the inductance characteristics can be further improved. In the case of such a closed magnetic circuit structure, the distance between the magnetic ribbon disposed on the outer portion of the winding and the outer portion of the winding facing the magnetic ribbon is 2 m at the maximum.
By setting m or less, the inductance characteristics can be further improved.

In the method of manufacturing an inductance element according to the present invention, a step of applying a winding to an outer periphery of a bobbin having a hollow portion having at least one open end, and disposing at least a part of a magnetic ribbon in the hollow portion of the bobbin is provided. Providing a lead terminal to the bobbin, and electrically connecting an end of the winding to the lead terminal, and insulating a portion of the lead terminal except at least an end opposite to the bobbin. Covering with a body.

The magnetic ribbon may be arranged so as to pass through the hollow portion, pass through the outside of the winding and penetrate the hollow portion again, and both ends thereof are magnetically connected. preferable.

As described above, the inductance element of the present invention has good characteristics as a current delay element of, for example, a snubber circuit of a switching power supply. The snubber circuit of the present invention can obtain excellent characteristics by connecting such an inductance element to the drive circuit of the switching element.

[0024]

Embodiments of the present invention will be described below.

FIG. 1 is an external view showing an embodiment of the inductance element of the present invention.

The inductance element 1 shown in FIG. 1 has a coil portion covered by a resin case 2 made of an insulator. By covering at least the periphery of the coil in this manner, insulation of these portions can be ensured, and breakage due to external impact or the like can be suppressed. It is preferable that the resin case 2 has such a size that the lead terminals 3 are not entirely covered. By covering the lead terminal 3 with the resin case 2 except for the end portion, the insulation of the coil portion can be ensured without hindering the mounting on the substrate or the like.

FIG. 2 is an external view showing another embodiment of the present invention.

The inductance element 1 shown in FIG.
The coil portion and the base portion of the lead terminal 3 are resin-coated. By forming such a resin-coated portion 4, it is possible to secure insulation properties at the periphery of the coil and to suppress damage due to an external impact or the like. Although the resin coating portion 4 may be formed only on the coil portion, for example, as shown in FIG. 2, by forming the resin coating on at least the root portion of the lead terminal 3, the lead terminal 3 from the inductance element can be formed. Dropping and damage to the base can be suppressed. Preferably, by forming the resin coating from the base portion to a predetermined portion, it is possible to suppress the bending and bending of the lead terminal 3.

The element may be entirely covered with a case or a coating as shown in FIGS. 1 and 2, or may be provided with holes 2a and 2b in a part of the case 2 as shown in FIG. There may be.

By providing such holes, an effect of radiating heat generated during operation of the element can be obtained. In particular, since the inductance element of the present invention has a coil wound in a predetermined amount, it is relatively easy to generate heat. By providing a hole for heat radiation, heat generation can be suppressed.

Although the size of the hole is not particularly limited, a form in which one to three holes having a diameter of about 0.3 to 1.5 mm are preferably provided. If the diameter of the hole is less than 0.3 mm, the effect of heat radiation is small, and if it exceeds 1.5 mm, the effect of covering the element with an insulator cannot be obtained. Similarly, when four or more holes are provided, it is difficult to obtain the effect of covering with an insulator.
Further, the shape of the hole is not limited to a perfect circle, and there is no problem even if it is an ellipse, a polygon, or the like.

Next, the internal structure of the inductance element of the present invention will be described.

FIG. 4 is an external view showing a part of the closed magnetic circuit type inductance element before a resin case, a resin coating or the like is formed. FIG. 5 is a sectional view of the inductance element shown in FIG.

As shown in FIG. 4, the bobbin 5 has a hollow portion 6 whose both ends are open. A winding 7 is provided on the outer periphery of the bobbin 5.

Further, as shown in FIG. 5, a magnetic ribbon 8 is disposed so as to penetrate through the hollow portion 6 of the bobbin 5, and both ends of the magnetic ribbon 8 are connected outside the bobbin 5 by connecting portions 9 Are connected magnetically. That is, the magnetic ribbon 8 forms a closed magnetic circuit loop including a part of the winding 7 via the hollow portion 6.

Further, the bobbin 5 is provided with a lead terminal 3, and each end of the winding 7 is electrically connected to the lead terminal 3.

As the winding 7 of such an inductance element, for example, an insulated conductor is used. Such a winding 7
Is wound on the outer peripheral surface of the bobbin 5 such that the number of turns (N) per 10 mm of the coil length is 20 or more and 500 or less.

In such a coil, a length of 10 mm
If the number of turns per unit (N) is less than 20, sufficient inductance characteristics cannot be obtained when a magnetic ribbon having a very small cross-sectional area is used as the core. On the other hand, if the number of turns (N) per 10 mm in length exceeds 500, the density of the windings 7 becomes too large, the stray capacitance between the windings 7 increases, and the function as an inductance element becomes saturated, and the efficiency increases. No improvement can be seen.
In addition, since the number of turns of the coil is large, the thickness of the portion where the coil is wound becomes large, making it difficult to reduce the size of the element.

The magnetic ribbon 8 has a thickness of 4 μm or more and 50 μm or more.
m and a width of 2 mm or more and 40 mm or less. If the thickness of the magnetic ribbon 8 exceeds 50 μm, eddy current loss and the like increase, and loss particularly in a high frequency range increases. On the other hand, if the thickness of the magnetic ribbon 8 is less than 4 μm, manufacturability may be reduced, surface smoothness may be degraded, and pinholes and the like may increase. The thickness of the magnetic ribbon 8 is further 10
It is preferable that the thickness be not less than μm and not more than 30 μm.

Further, by setting the width of the magnetic ribbon 8 within the above-mentioned range, problems such as bending at the time of bobbin insertion are reduced, the handling efficiency is improved, the manufacturing efficiency is improved, and the high-frequency loss is further reduced. An inductance element can be obtained.

According to the present invention, the magnetic ribbon 8 is effective enough even with a single layer.
It is also possible to laminate them. When a plurality of layers of the magnetic ribbon 8 are used, the shape of each magnetic ribbon 8 is set within the range of the numerical values described above.

In the inductance element according to the present invention, the ratio (N / n) of the number of turns (N) per 10 mm length of the coil to the number of laminations (n) of the magnetic ribbon 8 is 20 or more and 5 or more.
00 or less. Number of coil turns (N) and magnetic ribbon 8
By setting the relationship with the number of laminations (n) within the above-mentioned range of the N / n ratio, even when the magnetic ribbon 8 having a thickness of 4 μm or more and 50 μm or less is used as a single layer, for example, Sufficient inductance characteristics can be obtained.

That is, when the N / n ratio is less than 20,
With the inductance element of the present invention having the magnetic ribbon 8 having a small cross-sectional area as the core, sufficient inductance characteristics cannot be secured. On the other hand, if the N / n ratio exceeds 500, the density of the windings 7 increases and lap winding is required, and the stray capacitance between the windings 7 increases, and the function of the element is saturated. More preferably, the N / n ratio is 20 or more and 250 or less.

The number of layers (n) of the magnetic ribbons 8 is N
The ratio is not particularly limited as long as it satisfies the range of the / n ratio. However, it is preferable to use three layers or less in order to reduce the size of the inductance element. When the magnetic ribbon 8 is a single layer, the number of layers (n) is naturally one. Note that the number of laminated magnetic ribbon (n), and indicates the number of magnetic ribbon in the bobbin, specifically the coil wound on the bobbin in the length direction L _W from the center of the bobbin A straight line is drawn in the thickness direction (depth), and the number of magnetic ribbons in contact with the straight line is defined as n. For example, when only a single-layer magnetic ribbon is inserted into the bobbin, n = 1. When two magnetic ribbons are inserted, n = 2, and when a single magnetic ribbon is bent and inserted, the number of contact between the magnetic ribbon and the straight line is two. Becomes

In the inductance element of the present invention,
In addition to the above-mentioned N / n ratio, the ratio (N / t) of the number of turns (N) per 10 mm length of the coil to the thickness (t: μm) of the magnetic ribbon 8 is 1 to 100 [/ μm]. It is preferable to set the following. By satisfying such a relationship, it is possible to obtain better inductance characteristics.
When a plurality of magnetic ribbons 8 are stacked and used, the thickness (t) is the total thickness of the plurality of layers.

That is, when the N / t ratio is less than 1 [/ μm], it is difficult for the inductance element of the present invention having the magnetic ribbon 8 having a small cross-sectional area as a core to secure sufficient inductance characteristics. On the other hand, when the N / t ratio is 100 [/ μ
m], the density of the windings 7 is increased and lap winding is required, and the stray capacitance between the windings 7 increases, so that the inductance of the element decreases. More preferably, the N / t ratio is set to 3 or more and 20 [/ μm] or less.

The magnetic ribbon 8 may be made of various soft materials such as a crystalline soft magnetic alloy, an amorphous soft magnetic alloy, and a soft magnetic alloy having a microcrystalline structure (hereinafter, referred to as a microcrystalline soft magnetic alloy). A magnetic material can be applied. Among them, in the present invention, it is particularly preferable to use an amorphous soft magnetic alloy or a microcrystalline soft magnetic alloy.

As the crystalline soft magnetic alloy, for example, a permalloy is cited. Specifically, Ni is 55 to 85
It is preferable to use a permalloy alloy containing 7% by mass or less of Mo, 7% by mass or less of Mo, 2 to 27% by mass of Cu, and the balance substantially composed of Fe.

The magnetic ribbon 8 made of a permalloy is formed into an alloy thin plate by, for example, a melting method, and then subjected to hot rolling and cold rolling to form a ribbon having a predetermined thickness (4 to 50 μm). It can be obtained by: The magnetic properties of the obtained ribbon are adjusted by heat treatment in a magnetic field.

When the magnetic ribbon 8 is made of an amorphous soft magnetic alloy, a Co-based amorphous alloy, a Fe-based amorphous alloy,
-It is preferable to use a Ni-based amorphous alloy or the like. Co
As an amorphous alloy of a base group and a Fe group, a general formula: (M _1-a M ′ _a ) _100-x X _x (where M is at least one selected from Fe and Co)
M ′ is Ti, V, Cr, Mn, Ni, C
u, Zr, Nb, Mo, Ta, W, etc., at least one element selected from X, X represents at least one element selected from B, Si, C, P, etc., and a and x each represent 0 ≦ a ≦ 0.5, 10 ≦ x ≦ 35 at%) are exemplified.

Fe and Co as M elements have a magnetic flux density,
The composition ratio is adjusted in accordance with required magnetic properties such as iron loss and sensitivity to minute current. The M 'element is an element added for the purpose of controlling thermal stability, corrosion resistance, crystallization temperature and the like, and it is particularly preferable to use Cr, Mn, Zr, Nb, Mo, or the like. Element X is an essential element for obtaining an amorphous alloy. B is an element effective for making the alloy amorphous, and Si is an element effective for promoting the formation of an amorphous phase and increasing the crystallization temperature.

[0052] As the Fe-Ni based amorphous alloys, the general _{formula: (Ni 1-b Fe b} ) 100-yzw M "y Si z B w ( wherein, M" is V, Cr, Mn, Co, Nb, Mo, T
a, W, at least one element selected from Zr and the like, and b, y, z and w each represent 0.2 ≦ b ≦ 0.
5,005 ≦ y ≦ 10 at%, 4 ≦ z ≦ 12 at%, 5 ≦
(the number satisfies w ≦ 20 atomic% and 15 ≦ z + w ≦ 30 atomic%).

The Fe—Ni-based amorphous alloy should be manufactured at a lower cost than the above-mentioned Co-based amorphous alloy while obtaining good magnetic properties by using Ni-rich Fe—Ni as a base. Is made possible. The M ″ element is an element added for controlling thermal stability, corrosion resistance, and crystallization temperature, and it is particularly preferable to use Cr, Mn, Co, Nb, or the like.

The magnetic ribbon 8 made of an amorphous soft magnetic alloy is
For example, it is produced by a liquid quenching method. Specifically, it can be obtained by rapidly cooling an alloy material adjusted to a predetermined composition ratio from a molten state at a cooling rate of 10 ⁵ ° C / sec or more. By such a liquid quenching method, an amorphous alloy ribbon having a thickness in the range of 4 to 50 μm is obtained. The thickness of the amorphous alloy ribbon is 25μ
m, and more preferably 8 or less.
〜20 μm. By controlling the thickness of the ribbon, a low loss core can be obtained.

[0055] The microcrystalline soft magnetic alloy be applied to the magnetic ribbon 8, the general _{formula: Fe 100-cdef Cu c A} d Si e B f ( wherein, A is Ti, Zr, Hf, V, Nb, Ta , C
represents at least one element selected from r, Mo, W, Mn, Ni, Co and Al, where c, d, e and f are respectively 0.01 ≦ c ≦ 4 atomic%, 0.01 ≦ d ≦ 10 Atomic%, 10 ≦ e ≦ 25 atomic%, 3 ≦ f ≦ 12 atomic%, 17 ≦
e + f ≦ 30 atomic%), and those having fine crystal grains having an average particle diameter of, for example, 50 nm or less, which are substantially composed of an Fe-based alloy.

Here, Cu is an element effective in improving corrosion resistance and preventing coarsening of crystal grains and improving soft magnetic properties such as iron loss and magnetic permeability. Element A is an element that is effective for making the crystal grain size uniform, reducing magnetostriction and magnetic anisotropy, and improving magnetic properties against temperature change. The microcrystalline structure preferably has a form in which crystal grains having a grain size of 5 to 30 nm are present in the alloy at a surface kneading ratio of 50 to 90%.

The magnetic ribbon 8 made of a Fe-based microcrystalline soft magnetic alloy is prepared, for example, by preparing an amorphous alloy ribbon by a liquid quenching method, and then setting the temperature in the range of -50 to + 120 ° C. with respect to the crystallization temperature. For 1 minute to 5 hours to precipitate fine crystals, or a method of directly depositing fine crystals by controlling the quenching rate of the liquid quenching method. By performing heat treatment while applying a magnetic field in the width direction of such a microcrystalline soft magnetic alloy ribbon, a predetermined DC squareness ratio can be obtained.

The constituent material of the magnetic ribbon 8 is appropriately selected and used according to the application of the inductance element. For example, in order to obtain a saturable inductor having high magnetic permeability, it is preferable to use a Co-based amorphous soft magnetic alloy. If the coil is a small smooth choke coil, F
It is preferable to use an e-based microcrystalline soft magnetic alloy, an Fe-based amorphous soft magnetic alloy, or the like. Further, by using the magnetic ribbon 8 without heat treatment, it is possible to prevent the magnetic ribbon 8 from being embrittled. By preventing embrittlement of the magnetic ribbon 8, it is possible to reduce breakage of the magnetic ribbon 8 when a closed magnetic circuit loop structure as shown in FIGS. 4 and 5, for example, is applied.

Magnetic ribbon 8 for forming a closed magnetic circuit loop
Are laminated, for example, such that the front surface of one end of the magnetic ribbon 8 and the back surface of the other end partially overlap, and this laminated portion is tape 10 as shown in FIG.
It is carried out by fixing with. Various fixing methods can be applied to the connection between the ends of the magnetic ribbon 8 as long as a closed magnetic circuit loop can be formed. For example, fixing with an adhesive or an adhesive tape, welding stop, welding or the like is used.

When the magnetic ribbon 8 forms a closed magnetic circuit loop, when the length of one circumference of the loop-shaped magnetic ribbon 8 whose ends are connected is an average magnetic path length (Lc), this average The ratio (L) of the magnetic path length (Lc) to the length (Lw) of the coil winding 7
It is preferable to set the length of the magnetic ribbon 8 such that c / Lw) is 6 or less. Even if the Lc / Lw ratio is larger than 6, no improvement in inductance characteristics is observed, and the magnetic ribbon 8 is wasted. Further, the distance (W) between the magnetic ribbon 8 and the winding 7 is preferably as small as possible, and is preferably 2 mm or less. By setting the distance (W) between the magnetic ribbon 8 and the winding 7 to 2 mm or less, the inductance characteristics can be improved.

Magnetic ribbon 8 for forming a closed magnetic circuit loop
Is connected to the bobbin 5 as shown in FIGS.
May be arranged outside the bobbin 5, as shown in FIG.
It is better to dispose it in the hollow portion 6. As shown in FIG. 7, the connecting portion 9 is formed by laminating the front surface 10a at one end of the magnetic ribbon 8 and the back surface 10b at the other end. Is twice as large. By arranging such a portion in the hollow portion 6, the inductance characteristics can be further improved.

That is, when an electric current is applied to a solenoid type coil, the generated magnetic field is strongly affected inside the coil. Therefore, in the hollow portion 6 corresponding to the inside of the coil,
By arranging the connection portion 9 in which the cross-sectional area of the magnetic ribbon 8 is doubled, the inductance characteristics can be further improved.

The lamination length of the magnetic ribbon 8 at the connection portion 9,
In other words, it is preferable that the length (Lg) of the connecting portion 9 be 60% or less of the average magnetic path length (Lc) of the magnetic ribbon 8.
If the length (Lg) of the connecting portion 9 is set too long, the assemblability of the coil is reduced. On the other hand, in order to obtain the above-described effect of improving the inductance characteristics, the length (Lg) of the connecting portion 9 is set to be 10 times the average magnetic path length (Lc) of the magnetic ribbon 8.
% Is preferable.

Magnetic ribbon 8 for forming a closed magnetic circuit loop
Is not limited to the structure in which the front and back surfaces of the end portions are stacked as shown in FIGS. FIG. 8 is an external view showing another connection structure of the magnetic ribbon 8, and FIG. 9 is a sectional view thereof. The bobbin 5 shown in FIGS. 8 and 9 has a slit 11 connected to the hollow portion 6 at one end. One end of the magnetic ribbon 8 is returned to the hollow portion 6 through the slit 11, and both ends of the magnetic ribbon 8 are magnetically connected to each other. In this way, a closed magnetic circuit loop can be formed. In this case, since the contact is maintained by the stress of the magnetic ribbon 8, the fixing with an adhesive or the like can be omitted.

In the present invention, each functional element having such an internal structure is covered with an insulator. As a method of covering with an insulator, it is possible to ensure insulation from the outside by, for example, housing in a box-shaped insulating case 2 or resin coating with an epoxy resin or the like.

In such housing and resin coating, it is preferable to house the housing and apply resin so that the distance (W) between the outside of the winding and the inside of the magnetic ribbon is 2 mm or less. Distance (W) is 2mm
By performing the following, the inductance characteristics can be improved, and when applied to a switching device, the power supply efficiency can be improved.

In order to keep the distance (W) at 2 mm or less, the size of the case portion that covers the magnetic ribbon is adjusted so that the magnetic ribbon is closer to the winding or when the resin is coated with a resin. A method of arranging the coil so that the magnetic ribbon located outside the winding is on the upper side, approaching the winding with the weight of the magnetic ribbon itself, and applying a resin coating.

As a method of covering with an insulator, it is possible to use a resin film or a resin tube in addition to the resin case and the resin coating. As the resin tube, it is possible to use a resin tube that shrinks by heat, and to bring the magnetic ribbon closer to the winding by the shrinkage. The material used for these insulators is not limited as long as it has an insulating property. Preferred materials include phenol resin, PET, PBT and the like.

Although the inductance element of the present invention has been described above, the inductance element of the present invention is not limited to the above-described closed magnetic circuit structure, but may have an open magnetic circuit structure.

As an open magnetic circuit structure, for example, there is a form in which a magnetic ribbon is inserted into a bobbin having one end sealed. Examples of the shape of the magnetic ribbon used in such an open magnetic circuit structure include a plate-like shape and a shape in which a plate-like magnetic ribbon is bent and inserted.

Next, a method for manufacturing the inductance element of the present invention will be described.

First, on the outer periphery of a bobbin having a hollow portion,
Winding is performed so that the number of turns (N) per 10 mm length is 20 or more and 500 or less. Specific number of turns of winding 7 (N)
Means that the ratio (N / n) between the number of turns (N) and the number of stacked magnetic ribbons (n) is 2 according to the thickness (t) of the magnetic ribbon to be used.
It is set so that it becomes 0 or more and 500 or less.

Next, a magnetic ribbon is penetrated through the hollow portion of the bobbin 10, and the ends of the magnetic ribbon are connected to each other outside the bobbin to form a closed magnetic circuit loop. Move into the hollow part of. Further, a lead terminal is provided on the bobbin, and an end of the winding is electrically connected to the lead terminal.

Thereafter, an insulating case, a resin coating or the like is applied to secure the insulating property of the inductance element. At this time, resin coating or the like is performed so that the distance (W) between the outer peripheral portion of the winding and the magnetic ribbon is at most 2 mm or less.

In the present invention, the order of the respective steps may be changed as appropriate, for example, the winding process is performed after the lead terminals are provided on the bobbin.

In the present invention, by defining the N / n ratio, the N / t ratio, and the like, sufficient inductance characteristics can be obtained even though a magnetic ribbon having a very small cross-sectional area is used as the core. Can be.

Particularly, in an inductance element in which the distance (W) between the outer peripheral portion of the winding and the magnetic ribbon is 2 mm or less at maximum, good saturable inductor characteristics can be obtained.

According to the method of manufacturing an inductance element of the present invention, for example, after performing an automated winding process, a magnetic ribbon can be inserted into the hollow portion of the bobbin to form a core. Can be made much more efficient. That is, the manufacturing cost of the inductance element can be reduced.

Next, an embodiment of the snubber circuit of the present invention will be described.

The snubber circuit of the present invention includes the above-described inductance element 1 of the present invention, and this inductance element 1 is used by being connected to a drive circuit of a switching element. FIG. 10 is a circuit diagram illustrating a configuration example of a self-excited flyback type switching power supply using the snubber circuit of the present invention.

In FIG. 10, a primary winding 15 of a transformer 14 and an FET 16 as a switching element are connected in series between input terminals 12 and 13. The transformer 14 has a drive circuit for the FET 16 as an FET 1
A winding 17 for driving the gate circuit 6 is provided. That is, the winding 17 is a positive feedback winding of the transformer 14 that is wound to cause the FET 16 to self-oscillate. FE
A saturable inductor 18, a resistor 19, and a capacitor 2 are provided between the gate circuit of T16 and the FET drive winding 17.
0 are connected in series, and these are connected to the snubber circuit 21.
Is composed.

The resistor 19 provides an appropriate drive current to the FET 16 and the capacitor 20 is connected to the FET 1
6 are arbitrarily connected to improve the drive characteristics. These are preferably connected in series with the saturable inductor 18, respectively. The inductance element 1 of the present invention is used as the saturable inductor 18 in the snubber circuit 21.

The primary winding 15 of the transformer 14 and the input terminal 1
3, a snubber capacitor 22 for absorbing a surge voltage generated in the primary winding 15 of the transformer 14 is connected in series. Further, a snubber resistor 23 is connected in series with the snubber capacitor 22 to reduce the rate of change di / dt of the charging current i. The transformer 1
4 is similar to a conventional switching power supply, and a rectifier 25 and a capacitor 26 are connected as an output smoothing circuit.

In the switching power supply as described above, the saturable inductor 18 to which the inductance element 1 of the present invention is applied effectively functions as a current delay element for delaying the gate signal of the FET 16. Therefore, FET16
Can be satisfactorily switched to zero volts.
With these, the FET 16 as a switching element
, And a reduction in surge current and an improvement in efficiency as a power supply can be simply and effectively realized.

[0085]

Next, specific examples of the present invention and evaluation results thereof will be described.

Examples 1 to 6 and Comparative Examples 1 and 2 First, a bobbin having a square shape with a height of 13 mm, a width of 6 mm and a depth of 1.5 mm and made of a phenol resin was prepared. The bobbin was provided with a hollow portion having a cross section of 5 × 0.3 mm. Further, two solder-plated 0.6 mm square conductors were pressed into the bottom surface of the bobbin to form lead terminals.

The above-described bobbin was wound with a urethane wire having a diameter of 0.1 mm for 150 turns. The winding length Lw of the coil was unified at 12 mm.

The coating was peeled off from both ends of the winding and soldered to the two lead terminals, respectively. Specifically, after the winding ends were wrapped around the lead terminals, they were immersed in a solder bath to melt the coating and soldered.

Next, a magnetic material having a thickness of 18 μm and a width of 4.5 was used.
A Co-based amorphous alloy ribbon having a thickness of 1 mm was prepared and used as a single layer. The Co-based amorphous alloy ribbon was inserted into the hollow portion by penetrating the hollow portion, and the both ends of the alloy ribbon were laminated in a loop shape, and the laminated portion was fixed with tape. The length of the laminated portion of the alloy ribbon was 9 mm.

Further, a phenol resin coating was applied so as to cover the coil, the winding and the alloy ribbon (Example 1,
2) A PBT resin case (Examples 3 and 4) or a PET film (Examples 5 and 6) were formed. At this time, the coating, the case or the film was formed such that the distance between the winding and the alloy ribbon was 2 mm or less.

Next, these inductance elements are shown in FIG.
The characteristics as a delay element were measured and evaluated using the switching power supply shown in FIG. The power supply used was a self-excited flyback power supply, which was inserted in series with the gate of the switching element, and its noise reduction was confirmed. Input is 140VDC, load condition is 24V, 1.5A
And

As a comparative example of the present invention, an insulator similar to that of Example 1 (Comparative Example 1) and an insulator were used except that an insulator was not provided and the distance between the outer peripheral portion of the winding and the alloy ribbon was 2 mm. Except that the distance between the outer periphery of the winding and the alloy ribbon was 3 mm, the same (Comparative Example 2) as in Example 1 was produced, and the same evaluation as in Example 1 was performed.

Table 1 shows the type of insulator used in each of the examples and comparative examples, and the distance (W) between the winding and the alloy ribbon. In addition, inductance, surge current and power supply efficiency are also shown as evaluation results.

[0094]

[Table 1] As is clear from Table 1, the coating, the case or the film formed has excellent inductance characteristics,
It was recognized that the surge current was also effectively suppressed.

In particular, it has been found that, when the distance between the winding and the alloy ribbon is reduced, the inductance characteristics can be clearly improved and the surge current can be suppressed as compared with the case where the distance is not so.

Example 7 A device similar to the inductance device used in Example 3 was prepared except that two holes having a diameter of 0.8 mm were provided in the upper part of the outer case.

Next, a direct current of 0.3 [A] was applied to the inductance elements of Examples 3 and 7, and the surface temperature of the inductance elements was measured. Further, the efficiency was improved in the same manner as in Examples 1 to 6 and Comparative Examples 1 and 2.
[%] Was measured.

Regarding the measurement of the surface temperature, three arbitrary points were selected from the surface of the inductance element, measured with a thermocouple, and displayed as an average value. In addition, at the time of temperature measurement with a thermocouple, the temperature difference ΔT was measured as the difference from room temperature (25 ° C.). Table 2 shows the results.

[0099]

[Table 2] As is clear from Table 2, it was recognized that the device provided with the holes can suppress the temperature rise of the device. By reducing the temperature rise, an improvement in efficiency is recognized, and the effect of heat on other elements can be reduced, so that the reliability of the device can be improved.

Examples 8 to 9 and Comparative Examples 3 and 4 Example 8 was the same as Example 3 except that the number of turns of the winding of the inductance element was 300, and the number of turns of the winding was 300. Except for this, Example 9 was the same as Example 4, and the inductance, surge current, and efficiency were measured in the same manner as Example 3.

For comparison, the number of turns of the coil is set to 100.
The same test as in Examples 8 and 9 was performed, except that Comparative Example 3 was the same as Example 3 except that the value was 0. Table 3 shows the results.

[0102]

[Table 3] As can be seen from Table 3, the inductance elements of Examples 8 and 9 in which the number of turns of the coil is N = 300 and the number of layers of the magnetic ribbon is n = 1 show excellent characteristics.

It was also found that Comparative Example 3 in which N = 1000 and n = 1 exhibited excellent characteristics. However, since the number of turns (N) of the coil was large, the thickness of the coil was large and could not be accommodated in an insulating case having the same size as the other examples. Thus, N / n is 20 or more and 500
It has been found that when the N / n exceeds 500 outside the following range, especially, the element cannot be miniaturized.

For comparison, Comparative Example 4 was the same as Example 3 except that the number of turns of the coil was 10.
When the inductance L was measured, only about 2 [μH] was obtained, and it was found that it did not function as an inductance element.

[0105]

As described above, the inductance element of the present invention is excellent in the efficiency of the winding operation, can easily automate the winding operation, and has the insulating property by covering the outside of the inductance element with the insulating resin. Characteristics, inductance characteristics, surge current suppression and the like can be improved.

[Brief description of the drawings]

FIG. 1 is an external view showing an example of an inductance element of the present invention.

FIG. 2 is an external view showing another example of the inductance element of the present invention.

FIG. 3 is an external view showing another example of the inductance element of the present invention.

FIG. 4 is an external view showing an example of the internal structure of the inductance element of the present invention.

FIG. 5 is a sectional view showing an example of the internal structure of the inductance element of the present invention.

FIG. 6 is a cross-sectional view showing an example of a case where a connection portion of a magnetic ribbon is arranged in a hollow portion.

FIG. 7 is an enlarged sectional view of a connection portion of the magnetic ribbon.

FIG. 8 is an external view showing another example of the internal structure of the inductance element of the present invention.

FIG. 9 is a sectional view showing a section of the internal structure shown in FIG. 8;

FIG. 10 is a circuit diagram showing a configuration example of a switching power supply to which the snubber circuit of the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Inductance element 2 ... Resin case 2a, 2b ... Hole 3 ... Lead terminal 4 ... Coating part 5 ... Bobbin 6 ... Hollow part 7 ... Winding 8 ... Magnetic ribbon 9 ... Connection Department

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01F 31/00 FG (72) Inventor Kazumi Sakai 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Toshiba Corporation Inside the Yokohama Office (72) Inventor Takao Kusaka 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture F-term in the Toshiba Yokohama Office (Reference) 5E070 AA01 AB04 AB08 BA11 BB01 BB02 CA12 DA04 EA08

Claims (15)

[Claims] 1. The number of turns (N) per 10 mm length is 20
A coil having a hollow portion having both ends of the winding open, the coil having a thickness of 4 μm or more and 50 μm or less;
And a core comprising a single layer or a plurality of layers having a width of 2 mm or more and 40 mm or less, wherein at least a part of the magnetic ribbon is disposed in the hollow portion. Wherein the ratio (N / n) of the number of layers of the magnetic ribbon to the number of layers (n) is 20 or more and 500 or less, and at least an outer portion of the coil is covered with an insulator. element. 2. The ratio (N / N) of the number of turns (N) per 10 mm of the length of the coil to the thickness (t) μm of the magnetic ribbon.
2. The inductance element according to claim 1, wherein t) is not less than 1 / μm and not more than 100 / μm. 3. The method according to claim 1, wherein the insulator is a resin coating, a resin case, or a resin film.
Or the inductance element according to 2. 4. The coil further includes a cylindrical bobbin having a hollow portion, the winding is wound around an outer peripheral portion of the cylindrical bobbin, and the magnetic ribbon is formed in the hollow portion of the cylindrical bobbin. 2. The device as claimed in claim 1, wherein the device is inserted into the part.
The inductance element according to any one of claims 1 to 3. 5. The inductance element according to claim 4, wherein the cylindrical bobbin has a lead terminal electrically connected to the winding. 6. The inductance element according to claim 5, wherein the insulator covers the bobbin-side end of the lead terminal. 7. The insulator according to claim 1, wherein a hole for improving heat dissipation is provided in the insulator.
The inductance element according to any one of the above. 8. The magnetic ribbon is disposed so as to pass through the hollow portion, pass through the outside of the winding and penetrate the hollow portion again, and both ends thereof are magnetically connected. The inductance element according to any one of claims 1 to 7, wherein: 9. A gap between the magnetic ribbon disposed on an outer portion of the winding and an outer portion of the winding opposed to the magnetic ribbon is at most 2 mm or less.
The inductance element described. 10. A ratio (Lc / Lw) of an average magnetic path length (Lc) of the magnetic ribbon having the closed magnetic path structure to a winding length (Lw) of the coil is 6 or less. 10. The inductance element according to claim 8, wherein 11. The inductance element according to claim 8, wherein a connection portion of the magnetic ribbon having the closed magnetic circuit structure is disposed in the hollow portion. 12. The magnetic ribbon according to claim 1, wherein the magnetic ribbon is made of a crystalline soft magnetic alloy, an amorphous soft magnetic alloy, or a soft magnetic alloy having a microcrystalline structure.
2. The inductance element according to claim 1. 13. A step of applying a winding to an outer periphery of a bobbin having a hollow part having at least one open end, a step of arranging at least a part of a magnetic ribbon in the hollow part of the bobbin, and a lead on the bobbin. Providing a terminal, electrically connecting an end of the winding to the lead terminal, and covering a portion of the lead terminal except for at least an end opposite to the bobbin with an insulator. A method for manufacturing an inductance element, comprising: 14. The magnetic ribbon is arranged so as to pass through the hollow portion, pass through the outside of the winding and penetrate the hollow portion again, and both ends thereof are magnetically connected. The method for manufacturing an inductance element according to claim 13, wherein: 15. A snubber circuit comprising the inductance element according to claim 1 connected to a drive circuit of a switching element.