JP2001332426A - Thin magnetic core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance manufacturing yield after resin coating by enabling maintaining the reproducibility of the wound body shape (in particular, inner- diameter-side end part), in a magnetic core which uses a thin wound body. SOLUTION: This thin magnetic core comprises a wound body, formed by winding a thin band 2 of a soft magnetic alloy having a width of 5 mm or smaller into a toroidal shape and a resin-coating layer formed on the outer surface of the wound body by coating. The inner-diameter-side end part of the wound body, consisting of a plurality of layers of the thin band 2 of the soft magnetic alloy, for example 2-5 layers of the thin band of the soft magnetic alloy (3-6 sheets of stacked-layer count for the thin band of the soft magnetic alloy), is subjected to end-welding 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small and thin magnetic core used for a pulse transformer or the like and a magnetic component using the same.

[0002]

2. Description of the Related Art In recent years, as a constituent material of a transformer core and a choke coil core used for various electric and electronic parts such as a power supply circuit and a communication circuit, the magnetic permeability is high and the loss in a high frequency range is high. Therefore, amorphous magnetic alloys have been widely used because they have characteristics such as small magnetic flux density and large saturation magnetic flux density.

When a magnetic component is made of an amorphous magnetic alloy as described above, a magnetic core is formed by winding a thinned amorphous magnetic alloy, and a magnetic component is produced by winding the magnetic core. That is common. At this time, since the amorphous magnetic alloy ribbon has conductivity, the winding is applied after the surface (outer peripheral surface) of the core is insulated.

[0004] Insulation coating of a magnetic core is performed by applying a resin coating to the surface of the core, or housing the core in a resin case. The resin coating of the magnetic core is performed, for example, by spraying a resin powder for coating on the surface of the wound body of the amorphous magnetic alloy ribbon by spraying or by immersing the resin powder in a resin impregnating liquid and then thermosetting the resin. It is implemented by making it.

[0005] By the way, with respect to a magnetic core and a magnetic component using the same, it is required to further reduce the size and thickness in order to enable high-density mounting and the like. For example, a PC card for a personal computer or a portable information terminal (PD)
A) In addition, it is strongly required to reduce the thickness of magnetic components used in mobile communication devices and the like. For example, the height (the width of the magnetic alloy ribbon) is 5 mm or less, and Thin magnetic cores (winding bodies) having an outer diameter ratio exceeding 2 have been used as pulse transformers and the like.

A thin magnetic core (wound body) as described above
When winding a soft magnetic alloy ribbon such as an amorphous magnetic alloy ribbon, the edge on the inner radius side is first terminal-welded to 0 to 1 layer because the shape easily collapses from the inner diameter side end. After welding (welding between two ribbons), a soft magnetic alloy ribbon is wound so as to have a desired core shape. The outer diameter side end of the soft magnetic alloy ribbon is also usually welded.

[0007]

By the way, in the conventional thin magnetic core as described above, the outer surface of the wound body is coated with a resin even though the inner end is welded. Easily peels off from the inner diameter end. This is considered to be based on the stress generated at the time of resin coating, and in the thin magnetic core as described above, the stress at the time of coating acts in the direction of peeling off the inner diameter side end.

The conventional thin magnetic core has a problem that the production yield is low due to the peeling from the inner diameter side end as described above. For this reason, it is strongly desired that the production yield of the thin magnetic core be improved by preventing peeling from the inner diameter side end.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and enables the shape of a wound body to be maintained with good reproducibility even when a thin wound body is used. It aims to provide a magnetic core with an improved manufacturing yield, and furthermore, by using such a magnetic core, it is possible to improve the reliability and characteristics of the magnetic core while keeping it small and thin. It aims to provide parts.

[0010]

According to a first aspect of the present invention, there is provided a thin magnetic core comprising: a winding body formed by winding a soft magnetic alloy ribbon having a width of 5 mm or less in a toroidal shape; In a thin magnetic core comprising a resin coating layer formed on the outer peripheral surface of a wound body, the inner diameter side end of the wound body is subjected to terminal welding over a plurality of soft magnetic alloy ribbons. Features.

In the magnetic core of the present invention, it is preferable that the terminal welding of the inner diameter side end is performed over two to five layers of the soft magnetic alloy ribbon. Further, it is preferable that the terminal welding of the inner diameter side end is performed at a plurality of positions as described in claim 3.

Further, the magnetic core of the present invention is suitable for a thin magnetic core in which the width of a soft magnetic alloy ribbon is 2 mm or less, for example. Further, as described in claim 5, the width t of the soft magnetic alloy ribbon
This is particularly effective for a magnetic core having a ratio (D / t) of the outer diameter D of the wound body to 3 or more.

In the magnetic core of the present invention, the inner diameter side end of the wound body is terminal-welded over a plurality of soft magnetic alloy ribbons (for example, two to five soft magnetic alloy ribbons). In other words, the end portion on the inner diameter side of the wound body is subjected to terminal welding over three or more soft magnetic alloy ribbons (for example, 3 to 6 soft magnetic alloy ribbons). In this way, by performing terminal welding over a plurality of layers of the soft magnetic alloy ribbon, the fixed state of the inner diameter side end of the wound body becomes strong and stable. Therefore, even if stress occurs when the outer surface of the wound body is coated with the resin, peeling from the inner diameter side end can be prevented, and the production yield of the thin magnetic core can be greatly increased. .

According to a seventh aspect of the present invention, there is provided a magnetic component including the above-described magnetic core of the present invention and a winding provided on the magnetic core. As a specific example of the magnetic component of the present invention, as described in claim 8, a transformer such as a power supply or oscillation transformer, a pulse transformer for a communication circuit, or the like can be given. Further, it can be used for a choke coil or an inductance coil.

[0015]

Embodiments of the present invention will be described below.

FIG. 1 is a perspective view showing a main part (winding body) of a thin magnetic core according to one embodiment of the present invention. FIG.
FIG. 3 is a cross-sectional view showing the entire structure of the thin magnetic core, and FIG. 3 is a view schematically showing a welded state of the inner diameter side end of the wound body shown in FIG.

In these figures, reference numeral 1 denotes a core body composed of a wound body of a soft magnetic alloy ribbon 2. Examples of the soft magnetic alloy ribbon 2 constituting the core body (rolled body) 1 include, for example, an amorphous magnetic alloy ribbon of Co-based or Fe-based, an Fe-based soft magnetic alloy having fine crystal grains (hereinafter referred to as Fe-based A thin ribbon or the like is used.

Examples of the above-mentioned amorphous magnetic alloy ribbon include, for example, a general formula: (M _{1 -a} M ′ _a ) _100-b X _b (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 b each represent 0 ≦ a ≦ 0.15, 10 ≦ b ≦ 35 atomic%) whose composition is substantially represented.

[0019] As the Fe-based microcrystalline alloy thin strip, the general _{formula: Fe 100-cdefgh A c D} d E e Si f B g Z h ( wherein, A represents at least one element selected from Cu and Au
D is at least one element selected from group 4A, 5A, 6A and rare earth elements, and E is selected from Mn, Al, Ga, Ge, In, Sn and platinum group elements. Z represents at least one element selected from C, N and P, and c, d, e, f, g and h are 0 ≦ c ≦ 8, 0.1 ≦ d ≦ 15 , 0
≦ e ≦ 10, 0 ≦ f ≦ 25, 1 ≦ g ≦ 12, 0 ≦ h ≦ 10, 1 ≦ f + g + h ≦ 3
It is a number that satisfies each equation of 0. However, all the numbers in the above formula indicate atomic%), and those having fine crystal grains having an average particle diameter of, for example, 50 nm or less are exemplified.

The composition of the above-described amorphous magnetic alloy ribbon or Fe-based microcrystalline alloy ribbon is appropriately selected according to the intended use of the magnetic component formed using the thin magnetic core of the present invention. For example, when used as a component such as a transformer, it is preferable to use a Co-based amorphous magnetic alloy or a Fe-based microcrystalline alloy. Further, when applied to an inductance coil (saturable inductor) for a filter, resonance, or a mag amplifier, it is preferable to use a Co-based amorphous magnetic alloy having a high squareness ratio, and when applied to a choke coil, It is preferable to use an Fe-based amorphous magnetic alloy having excellent direct-current superposition characteristics.

In the present invention, the use of a crystalline magnetic alloy ribbon such as Permalloy or Sendust as the soft magnetic alloy ribbon 2 does not necessarily exclude the use of a magnetic component. It is preferable to use the above-described amorphous magnetic alloy ribbon or Fe-based microcrystalline alloy ribbon (particularly, amorphous magnetic alloy ribbon).

As shown in FIG. 2, the outer peripheral surface of the core body composed of the wound body 1 of the soft magnetic alloy ribbon 2 has a resin coating layer (exterior) made of a thermosetting insulating resin such as a fluororesin or an epoxy resin. 3), and these constitute a thin magnetic core 4. For the resin coating layer 3, it is particularly preferable to use a fluororesin represented by polytetrafluoroethylene (PTFE). According to the fluororesin, even when the thickness of the coating layer 3 is reduced, the entire outer peripheral surface of the core body (rolled body) 1 can be uniformly covered.

In the thin magnetic core 4 as described above,
The inner diameter side end of the winding body 1 constituting the core body is fixed by terminal welding (weld fixing part 5). As shown in FIG. 3, the terminal welding of the inner diameter side end portion is performed so that the welding fixing portion 5 extends over a plurality of layers of the soft magnetic alloy ribbon 2.
That is, the innermost soft magnetic alloy ribbon 2a is set at 0
As a layer, the welding fixing part 5 is provided so as to reach at least the first layer of the soft magnetic alloy ribbon 2b and the second layer of the soft magnetic alloy ribbon 2c wound thereon.

As described above, by performing terminal welding over a plurality of layers of soft magnetic alloy ribbons, in other words, by performing terminal welding over three or more soft magnetic alloy ribbons (2a to 2c), the wound body 1 is formed. The fixed state of the inner diameter side end portion can be made firm and stable. Therefore, the winding body 1
Even when stress is generated when the resin coating layer 3 is formed on the outer surface of the thin magnetic core 4, it is possible to prevent peeling from the inner diameter side end portion, and it is possible to greatly increase the production yield of the thin magnetic core 4. .

The above-mentioned terminal welding of the inner diameter side end of the wound body 1 is performed with two to five layers of soft magnetic alloy ribbons, in other words, three to six soft magnetic alloy ribbons, except for the zeroth layer of soft magnetic alloy ribbons. It is preferably applied over the magnetic alloy ribbon. If only the soft magnetic alloy ribbons of the 0th layer and the 1st layer are subjected to terminal welding, it is the same as a conventional magnetic core, and peeling is likely to occur from the inner diameter side end.

On the other hand, even if the terminal welding is performed beyond the soft magnetic alloy ribbon of the fifth layer, no further effect is obtained, and conversely, the fixing force of the innermost soft magnetic alloy ribbon 2a is reduced. It may decrease. In addition, since welding is a process involving heat, the soft magnetic alloy ribbon 2 is likely to be adversely affected. For example,
With respect to the amorphous alloy ribbon, the welded portion may be crystallized by the heat of welding, and if the number of welds is increased too much, the properties may be adversely affected. Furthermore, when welding 6 layers or more (for example, 20 sheets or more) of the soft magnetic alloy ribbon 2, it is necessary to increase the welding power (for example, the amount of electricity for spot welding), which causes a problem that the magnetic core is broken. There is a risk.
Therefore, the number of layers of the soft magnetic alloy ribbon 2 subjected to the welding process is 2 to 5
It is preferable to form a layer (three to six soft magnetic alloy ribbons).

The above-described terminal welding is performed by, for example, spot welding (electric welding). Note that another welding method such as laser welding may be applied as long as a similar fixing structure can be obtained. Further, it is preferable that the terminal welding 5 is performed at a plurality of positions (for example, 3 to 8 positions).
Thereby, the fixed state of the inner diameter side end of the winding body 1 can be further stabilized. At this time, the welding location may be concentrated near the end or may be dispersed over the entire circumference.

The stabilizing effect of the inner end portion according to the present invention is as follows.
This is remarkable for a thin magnetic core using a soft magnetic alloy ribbon 2 having a width of 5 mm or less. The present invention is even more effective when the width of the soft magnetic alloy ribbon 2 is 2 mm or less. Further, the present invention is particularly effective for a thin magnetic core in which the ratio (D / t) of the outer diameter D of the wound body 1 to the width t of the soft magnetic alloy ribbon 2 is 3 or more. Further, the present invention is particularly effective when the wound body 1 in which the number of turns of the soft magnetic alloy ribbon 2 is 50 or more, or more than 100 is used.

Such a thin magnetic core having a large ratio of an outer diameter to a ribbon width having a D / t ratio of 3 or more, and a thin magnetic core having a wound body 1 having 50 or more turns are coated with a resin. Since the wound body 1 is easily disintegrated from the inside by the stress at the time of performing, the effect of the present invention can be more effectively obtained.

The present invention exerts a further effect when the soft magnetic alloy ribbon 2 having a high surface property is used. That is, when the soft magnetic alloy ribbon 2 having a high surface property is used, peeling tends to occur particularly from the inner end portion. Such a wound body 1
On the other hand, when terminal welding is performed over a plurality of layers of the soft magnetic alloy ribbon 2, the ability to maintain the shape of the wound body 1 can be enhanced. Here, the soft magnetic alloy ribbon 2 having a high surface property refers to a ribbon having a Ks value (= micro plate thickness / weight plate thickness) of 1.2 or less, for example.

The thin magnetic core 4 as described above is manufactured, for example, as follows.

That is, the soft magnetic alloy ribbon 2 is formed on the surface of the core.
When the number of turns is 2 to 5 (3 to 6 in the number of laminations of the soft magnetic alloy ribbon 2), for example, spot welding is performed to end-weld the inner diameter side end. The specific conditions of the terminal welding are as described above.

Next, the soft magnetic alloy ribbon 2 is wound by a usual method until the desired cross-sectional area is obtained, starting from the end welding of the inner diameter side end portion. Fix with tape or welding stopper. The amount of winding of the soft magnetic alloy ribbon 2, that is, the cross-sectional area of the wound body 1 of the soft magnetic alloy ribbon 2, is set according to the required characteristics of the target magnetic component.

Thereafter, the outer surface of the wound body 1 is coated with a resin to form an exterior, whereby the intended thin magnetic core 4 is obtained. The resin coating is performed by applying a powder resin, thermosetting, impregnating a resin liquid, thermosetting, or the like. The resin used for the resin coating is as described above.

The thin magnetic core 4 having a toroidal shape as described above is formed by winding a resin coating layer (exterior insulating coating layer) 3 on the core body (winding body) 1.
By providing a current path so as to be substantially orthogonal to the magnetic path of the above, it is used as a magnetic component such as a transformer or a choke coil. Such a magnetic component of the present invention is used, for example, as a power supply or oscillation transformer, a pulse transformer for a communication circuit, or the like. In some cases, it is used as a choke coil or an inductance coil. According to the magnetic component of the present invention, it is possible to achieve a reduction in size and thickness of a pulse transformer or the like based on the thin magnetic core 4 described above.

[0036]

Embodiments of the present invention will be described below.

Example 1 First, a Co-based amorphous magnetic alloy ribbon having a Ks value of 1.1, a plate thickness of 16 μm, and a width of 1 mm (composition: Co ₆₉ Fe ₄ Nb ₁ Cr ₁ Si)
₁₄ B ₁₁ ) is prepared and this is a 4 mm diameter core (circular cross section).
Wound. At this time, when the number of turns of the Co-based amorphous magnetic alloy ribbon becomes two (three laminations of the soft magnetic alloy ribbon 2), spot welding is performed at three places to form the Co-based amorphous magnetic alloy ribbon. The inner end was fixed.

Next, the Co-based amorphous magnetic alloy ribbon was wound until the number of turns was 130 (outer diameter: about 10 mm), starting from the end welding at the inner diameter side end. After welding and fixing the outer diameter side end (end) of the Co-based amorphous magnetic alloy ribbon, resin coating was applied to form an exterior. The resin coating was performed by a liquid spray method.
One hundred such thin magnetic cores were manufactured, and the yield after resin coating was evaluated. Table 1 shows the results.

Examples 2 to 4 In Example 1 described above, the terminal welding at the inner diameter side end was performed by 3 times.
Soft magnetic alloy ribbons of four layers (four layers: Example 2), four layers of soft magnetic alloy ribbons (five layers: Example 3), five layers of soft magnetic alloy ribbon (number of layers) 6 sheets: Except for Example 4),
Thin magnetic cores were produced in the same manner. For these, 100 thin magnetic cores were manufactured, and the yield after resin coating was evaluated. Table 1 shows the results.

Comparative Examples 1 and 2 In Example 1 described above, the end welding at the inner diameter side end was
Thin magnetic cores were produced in the same manner except that the soft magnetic alloy ribbon of one layer (Comparative Example 1) and the soft magnetic alloy ribbon of one layer (two laminated layers: Comparative Example 2) were used. About these
100 thin magnetic cores were fabricated and the yield after resin coating was evaluated. The results are shown in Table 1. The term "terminal welding to the zero-layer soft magnetic alloy ribbon" used herein refers to a core produced without welding the terminals.

[0041]

[Table 1] As is evident from Table 1, the thin magnetic cores according to the examples are excellent in maintaining the shape of the wound body, and thus, excellent yield can be obtained even after resin coating.

[0042]

As described above, according to the thin magnetic core of the present invention, even when a thin wound body is used, the shape of the wound body can be maintained with good reproducibility. The reliability can be greatly improved. Furthermore, by using such a thin magnetic core, it is possible to provide a magnetic component which is adapted for miniaturization and thickness reduction and which has improved reliability and characteristics.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part (winding body) of a thin magnetic core according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the entire structure of the thin magnetic core shown in FIG.

FIG. 3 is a diagram schematically showing a welding state of an inner diameter side end portion of the wound body shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Core body (winding body) 2 ... Soft magnetic alloy ribbon 3 ... Resin coating layer 4 ... Thin magnetic core 5 ... Welding fixing part

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H01F 19/04 H01F 19/04 U 27/24 27/24 C

Claims (8)

[Claims] 1. A thin magnetic core comprising: a wound body formed by winding a soft magnetic alloy ribbon having a width of 5 mm or less in a toroidal shape; and a resin coating layer formed on the outer peripheral surface of the wound body. A thin magnetic core, wherein an end on the inner diameter side of the wound body is subjected to terminal welding over a plurality of layers of a soft magnetic alloy ribbon. 2. The thin magnetic core according to claim 1, wherein the terminal welding is performed over two to five layers of the soft magnetic alloy ribbon. 3. The thin magnetic core according to claim 1, wherein the terminal welding is performed at a plurality of positions. 4. The thin magnetic core according to claim 1, wherein the soft magnetic alloy ribbon has a width of 2 mm or less. 5. The thin magnetic core according to claim 1, wherein the wound body has a ratio of an outer diameter D of the wound body to a width t of the soft magnetic alloy ribbon. A thin magnetic core, wherein (D / t) is 3 or more. 6. The thin magnetic core according to claim 1, wherein the soft magnetic alloy ribbon is an amorphous magnetic alloy ribbon or an Fe-based microcrystalline alloy ribbon. Thin magnetic core. 7. A magnetic component, comprising: the magnetic core according to claim 1; and a winding provided on the magnetic core. 8. The magnetic component according to claim 7, wherein the magnetic component is a transformer.