JPH11354344A - Inductance element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce inserting loss, to stabilize the electric characteristic for a long period and to facilitate assembling by using a heat resistant bond magnet, which specifies electric resistance or specifies the change of the irreversible demagnetization factor at the specified temperature with a permanent magnet. SOLUTION: An inductor element is constituted of magnetic cores 2 and 3 comprising EI soft magnetic material, a heat resistant bond magnet 1, which is arranged at the gap part of the magnetic cores, and a coil which is wound around the magnetic core. The heat resistant bond magnet 1 is manufactured by binding R-T-M-B-N based (R is one or more kinds of any of rare-earth elements including Y, and T is Fe or Fe, wherein a part is displaced into Co and/or Ni) magnetic powder with binder. Furthermore, the electric resistance of the heat resistant bond magnet 1 is set at 0.01-0.05 Ωcm, or the irreversible demagnetization-rate change from 0 deg.C to 120 deg.C is set within 2%. Furthermore, the 50 atom.% or more of the R component of the bond magnet is set to Sm, and the high coercive force is obtained. Furthermore, the average particle diameter of the magnetic power is set in the range of 10-120 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inductance element in which a permanent magnet is arranged in a magnetic core space and the DC bias characteristics are improved by the magnet.

[0002]

2. Description of the Related Art In general, an alternating current is superimposed on a direct current in an inductance element such as a transformer or a choke coil. Therefore, an air gap is provided in a magnetic core to avoid magnetic saturation due to a direct current magnetic field. However, to cope with even larger DC superposition,
The size of the magnetic core increases, the gap size increases, and the number of coil turns increases. As a result, the inductance element also increases in size. Therefore, there has been proposed an inductance element (first conventional example) in which a permanent magnet is disposed in a gap of a magnetic core, and a magnetic bias is applied in advance so as to cancel a DC magnetic field to effectively utilize the characteristics of the magnetic core. The permanent magnet is appropriately selected depending on the magnitude of the required magnetic bias and the magnitude of the demagnetizing field due to the coil of the inductance element. However, the inductance element used in a switching power supply or the like requires a large magnetic bias. Usually, a rare earth cobalt magnet having a large residual magnetic flux density and a large coercive force is used.

Japanese Patent Laid-Open Publication No. Sho 50-4570 describes an inductance element (second conventional example) in which a rare earth cobalt magnet arranged in a gap of a magnetic core is divided into a plurality.

Japanese Patent Application Laid-Open No. 50-133453 discloses an inductance element using a bonded magnet obtained by mixing a crushed rare earth cobalt magnet piece with an insulator and compressing and molding the same as a permanent magnet disposed in a gap of a magnetic core. (Third conventional example) is described.

[0005]

In the first prior art, a permanent magnet (rare earth cobalt magnet) is disposed in the gap of the magnetic core. However, since the rare earth cobalt magnet has an extremely small electric resistance of about 10 ^-5 Ωcm, the vortex is small. The current loss became large and generated heat. Since the temperature of the magnetic core rises with this heat generation, the magnetic characteristics of the magnetic core change, and the characteristics as an inductance element, such as a decrease in inductance, are significantly reduced.

In the second conventional example, the permanent magnet disposed in the air gap of the magnetic core is divided into a plurality of parts, so that the AC magnetic field of each part is reduced as compared with the case where the permanent magnet is integrated, thereby reducing eddy current loss. It is possible. However, in order to arrange a plurality of permanent magnets in the gap of the magnetic core while aligning the magnetization directions of the permanent magnets, the same poles of the permanent magnets repel each other, so that the permanent magnets cannot be kept in a predetermined space, or the permanent magnets cannot be fixed. A large number of man-hours are required for assembling the inductance element because magnets overlap.

In the third conventional example, the eddy current loss is reduced and the core of the permanent magnet is reduced by disposing a bonded magnet formed by mixing and compressing and molding a permanent magnet piece and an insulator in the gap of the magnetic core. It is stated that the arrangement in the gap can be facilitated. However, in the conventional bonded magnet, the particle diameter of each magnet powder is as small as about 3 to 5 μm, and the surface of the magnet is exposed due to cracks generated during molding. The magnetic properties deteriorated due to the reaction, and the magnetic properties were remarkably deteriorated particularly in a high temperature environment. Depending on the environment in which the inductance element is used, the bond magnet has a temperature of about 50 ° C., and if the ambient temperature is about 50 ° C., the self-temperature rise of the inductance element results in 100 ° C.
Before and after. At such temperatures, the magnetic properties of the bonded magnet degrade in hundreds of hours. For this reason, the conventional inductance element using the bonded magnet lacks long-term reliability and cannot be put to practical use.

The present invention has been made to solve the above-mentioned problems, and has as its object to provide an inductance element which has a small insertion loss, stable electric characteristics for a long period of time, and is easy to assemble.

[0009]

According to the present invention, there is provided an inductance element having a permanent magnet for applying a magnetic bias to a magnetic core gap, wherein the permanent magnet has an electric resistance of 0.01 to 0.01.
It is an inductance element using a heat-resistant bonded magnet having an irreversible demagnetization rate change of 0.05 Ωcm and 0 ° C. to 120 ° C. within 2%.

Further, according to the present invention, the bonded magnet is formed of RTB-
Nb-based (R is any one or more of rare earth elements including Y, T is Fe or Fe in which a part thereof is substituted with Co and / or Ni) magnet powder as a polymer, pure metal, alloy An inductance element using a rare earth bonded magnet combined with any one of the binders described above.

The composition component of the bonded magnet is R _α T
A _{100- (α + β + γ)} B β Nb γ, R is any one or more rare earth elements including Y, T is obtained by substituting Fe or partly Co and / or Ni Fe Wherein α, β, and γ are an atomic element using a rare-earth bonded magnet in which a rare-earth magnetic powder having an atomic percentage in the following range is bound with a binder of a polymer, a pure metal, or an alloy. 8 ≦ α ≦ 15 4 ≦ β ≦ 8 0.1 ≦ γ ≦ 2

Further, according to the present invention, the bonded magnet is made of R-T-M-
BN type (R is any one or more of rare earth elements including Y, T is Fe or Fe in which a part thereof is substituted by Co and / or Ni, M is Al, Ti, V, Cr, Mn, C
u, Ga, Zr, Nb, Mo, Hf, Ta, or any one or more of W) a rare earth bonded magnet in which a magnet powder is bonded with a binder of a polymer, a pure metal, or an alloy. This is the inductance element.

The above bonded magnet has a component composition of R _α T
_{100- (α + β + γ + δ)} M _β B _γ N _δ ,
Is one or more kinds of rare earth elements including Y, T is Fe or Fe partially substituted by Co and / or Ni, and M is Al, Ti, V, Cr, Mn, Cu ,
Any one of Ga, Zr, Nb, Mo, Hf, Ta, and W
Or a mixture of two or more species, wherein α, β, γ, and δ are atomic percentages of a rare earth magnet material powder in the following range, and a high molecular weight polymer, a pure metal, or a rare earth element which is bound with an alloy binder. This is an inductance element using a bonded magnet. 5 ≦ α ≦ 18 1 ≦ β ≦ 50 0.1 ≦ γ ≦ 5 4 ≦ δ ≦ 30

This is an inductance element in which 50% or more, preferably 70% or more, of the R component of the rare earth bonded magnet used in the present invention is Sm.

Further, the present invention is an inductance element using a rare earth bonded magnet in which the average particle size of the rare earth magnetic powder is in the range of 10 to 120 μm. The more preferable average particle diameter of the rare earth magnetic powder is 50 to 60 μm.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An inductance element according to the present invention will be described with reference to FIG. FIG. 1 is a perspective view of an inductance element according to one embodiment of the present invention. The inductance element according to the present invention has a gap in a part of a magnetic circuit. For example, the magnetic cores 2 and 3 made of an EI-shaped soft magnetic material, the heat-resistant bonded magnet 1 disposed in the gap of the core, and a coil wound around the core. And a magnetic bias from the heat-resistant bonded magnet 1 is applied in a direction opposite to a DC magnetic field generated by the coil.

The magnetic core is preferably formed of a soft magnetic material having a saturation magnetic flux density Bs of 450 mT or more, such as Mn-Zn ferrite, in view of the characteristics of the inductance element.

The heat-resistant bonded magnet is an RTB-Nb system (R is at least one of rare earth elements including Y, T is Fe or a part thereof is C or C) having improved electric resistance and irreversible demagnetization rate.
o) Fe-magnet powder, R-T-M-B-N type (R is any one or more of rare earth elements including Y, T is Fe or a part of Co and / or Ni Fe, M substituted for Al, Ti, V, Cr, Mn, Cu, Ga,
Zr, Nb, Mo, Hf, Ta, or any one or more of W) is prepared by binding a magnet powder with a binder.

As described above, the electric resistance of the heat-resistant bonded magnet is remarkably increased as compared with the first conventional example, and the eddy current loss can be reduced without using a means for dividing the permanent magnet as in the second conventional example. The insertion loss of the inductance element can be reduced, and the heat-resistant bonded magnet can be easily arranged in the magnetic core space. Also, due to the decrease in the irreversible demagnetization rate, an inductance element having excellent reliability in a high-temperature environment can be obtained.

As the binder for binding the magnet powder, a thermosetting resin represented by an epoxy resin or a phenol resin or a polyamide resin as a high molecular polymer;
A thermoplastic resin such as an EEA resin or a synthetic rubber, a natural rubber, or the like may be used. However, it is preferable to use a binder that does not cause softening or deterioration due to soldering such as an environmental temperature of the inductance element and flow or reflow.

A high coercive force is obtained by setting Sm to 50 atomic% or more, preferably 70% or more of the R component of the bonded magnet,
It is possible to suppress the demagnetization due to the magnetic flux generated in the core magnetic path of the inductance element, improve the electrical characteristics of the inductance element, and cope with a higher current.

The magnetic properties are mostly caused by the particle diameter of the magnetic powder. If the magnetic properties are too small, the quality and the formability deteriorate due to oxidation. If the magnetic properties are too large, the nitriding treatment becomes insufficient. An inductance element having stable characteristics can be obtained using a rare-earth bonded magnet of about 120 μm. In order to obtain further stable characteristics, the average particle size of the magnetic powder is preferably set to 40 to 50 μm.

[0023]

EXAMPLES (Example 1) First, a method for manufacturing a heat-resistant bonded magnet will be described. First, an MQP-O material manufactured by MQI (Magnequench International) having a composition of Nd _11.5 Fe _80.7 B ₆ Nb _1.8 in atomic% as a magnet powder was used and crushed to an average particle size of 110 μm by a bantam mill. The crushed powder was subjected to a surface treatment by adding 0.25% by weight of a silane coupling material manufactured by Nippon Unicar Co., Ltd. Next, a bisphenol type epoxy resin (Epicoat 807) manufactured by Yuka Shell Co. and DD which is an aromatic amine curing agent
S (diaminodiphenylsulfone) in a total amount of 2.6 wt% (E8
07: DDS = 100: 43.2)
The resin mixture is added to and mixed with the magnet powder or the kneaded material twice, and kneaded by a twin-screw kneader. First, in the first kneading, 80% of the total 2.6 wt% of the resin part was kneaded with the magnet powder, and the kneaded material was subjected to primary heat curing at 150 ° C. for 1 hour. Subsequently, at the time of the second kneading, the remaining 20% of the resin part was added and kneaded, followed by a secondary heat-curing treatment at 120 ° C. × 1 hour, followed by filling in a predetermined molding die and compression molding without a magnetic field. The obtained isotropic bonded magnet molded body is subjected to a main heat curing treatment (at 180 ° C. for 1 hour in air,
(90 ° C. × 4 hours) and 5.8 mm × 5.8 mm × 0.
A 48 mm heat-resistant bonded magnet 1 was obtained.

EI22 core made of Mn-Zn ferrite (manufactured by Hitachi Metals, material SB-5, material gap: 0.6 m)
m) incorporating a measuring coil into the center leg of the E-shaped core 2 of
The heat-resistant bonded magnet 1 was bonded so that the direction of magnetization was opposite to the direction of the magnetic field of the DC current flowing through the magnetic core, and an inductance element was fabricated in combination with the I-type core 3, and the loss was measured. The measuring coil is wound 36 times with a wire having a diameter of 0.4 as a primary winding and 36 times with a wire having a diameter of 0.4 as a secondary winding.

(Comparative Example 1) External dimensions are 2 mm × 2 mm ×
Using six rare earth cobalt magnets (H18B manufactured by Hitachi Metals, Ltd.) formed in a 0.3 mm square plate shape, an inductance element was manufactured under the same conditions as in Example 1. The magnetic force of the rare-earth cobalt magnet is made substantially equal to that of the heat-resistant bonded magnet of Example 1 depending on the outer dimensions. Hereinafter, since it is the same as the first embodiment, the description thereof is omitted.

(Comparative Example 2) An inductance element was manufactured under the same conditions as in Example 1 except that the structure did not include a permanent magnet. Hereinafter, since it is the same as the first embodiment, the description thereof is omitted.

The insertion loss of the inductance elements of the above Examples and Comparative Examples was measured at room temperature using a BH analyzer (model number: SY8232, manufactured by Iwasaki Communication Equipment Co., Ltd.). The measurement frequency is 20kHz to 200kHz
The magnetic flux density Bm was set to 20 mT, and the voltage obtained by the following equation was set as a set voltage (Vrms). Vrms = 4.44 × Bm × S × N × f where, Bm: magnetic flux density (T), S: core cross-sectional area (m ² ), N: number of coil turns (turn), f: frequency (Hz) is there. Table 1 shows the results obtained as described above.

[0028]

[Table 1]

Here, the insertion loss of the sample of Comparative Example 2 represents the loss of the magnetic core. Table 1 shows that the sample of Example 1 in which the permanent magnet giving the magnetic bias is a heat-resistant bonded magnet has a significantly lower loss than the sample of Comparative Example 1 in which the permanent magnet is a rare-earth cobalt magnet in which a small piece is used. It can be seen that the insertion loss is almost the same as the loss of the magnetic core shown in FIG.

Comparative Example 3 5.8 mm × 5.8 mm ×
Example 1 except that a neodymium bond magnet (HB-08I manufactured by Hitachi Metals, Ltd.) formed in a 0.48 mm square plate shape was used.
Similarly, an inductance element was formed. Example 1 below
The description is omitted because it is the same as.

The inductance element of Comparative Example 3 thus obtained was left in a constant temperature bath at a temperature of 100 ° C. for 2000 hours together with the inductance element of Example 1, and a high temperature test was performed. Before and 500 hours after the start of the test, 1000
After an elapse of 2,000 hours, the inductance element was taken out of the thermostat, and the inductance element was left at room temperature for 24 hours. Then, the DC superposed inductance was measured and evaluated at room temperature. The result is shown in FIG. FIG. 2 shows the DC superposition characteristics of the inductance element after 500 hours of the high-temperature test. The measurement conditions were in accordance with the measurement conditions of the dc superimposed inductance of JIS C2514, and the measurement circuit was a case where the dc was superimposed on the test coil. Note that the inductance elements of Example 1 and Comparative Example 3 are designed so that the DC superimposed inductance becomes 150 μH at a DC current of 3 A at room temperature.

FIG. 2 shows that the inductance of Example 1 did not deteriorate before and after the high temperature test, and did not change from the DC superposition characteristic shown in FIG. On the other hand, the inductance element of Comparative Example 3 had a DC superimposition characteristic almost equal to that of Example 1 before the test, but after 500 hours of the high-temperature test, the DC superposition inductance was reduced to about 135 μH at a DC current of 3 A, Further, after 1000 hours, the inductance was significantly deteriorated and was not practically usable.

(Example 2) Sm, F having a purity of 99.9%
e, Ti, B using Sm _8.3 Fe _bal B _2.0 Ti _3.0 N
Formulated in a mother alloy composition corresponding to the nitride magnet powder in _12.1 ,
Melted in a high-frequency melting furnace in an argon gas atmosphere, and then
Homogenization treatment was performed at 1150 ° C. for 20 hours in an argon gas atmosphere, and then this mother alloy block was pulverized using a jaw crusher and a disc mill. Next, the mother alloy powder was charged into an atmosphere heating furnace, and at 450 ° C. nitrogen gas 1 atm.
The substrate was heated and held in an air stream for 5 hours to perform a nitriding treatment, and then annealed at 420 ° C. for 1 hour in an argon stream. The average particle size of the magnetic powder was 10 μm. After kneading the magnetic powder with an epoxy resin, the mixture is compression-molded in a magnetic field of 10 kOe under a pressure of 10 ton / cm ² , and cured for 140 minutes.
Heat treatment was performed at 1 ° C. for 1 hour to obtain a heat-resistant bonded magnet. This bond magnet was able to obtain a high coercive force of 6.2 kOe.

Example 3 A bonded magnet having a component composition of Sm _6.2 Pr _2.0 Fe _bal B _2.0 Ti _4.0 N _12.3 was obtained in the same manner as in Example 2. The average particle size of the magnetic powder was 120 μm. This bonded magnet was able to obtain a coercive force of 6.8 kOe higher than that of the above bonded magnet.

The heat-resistant bonded magnets obtained in Examples 2 and 3 were used for the inductance element of Example 1 and were heated at a temperature of 10%.
It was left in a thermostat at 0 ° C. for 2000 hours to perform a high temperature test. Also in this test, in Example 2 and Example 3, the difference between the DC superimposition characteristic values before and after the test was very small, and a highly reliable inductance element was obtained as in Example 1.

[0036]

Since the present invention has the above-described structure, it is possible to obtain an inductance element having low insertion loss, stable electric characteristics for a long period of time, and simple assembly.

[Brief description of the drawings]

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

FIG. 2 is a high temperature test 500 of Example 1 of the present invention and Comparative Example 3.
DC superimposition characteristics after time

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat-resistant bonded magnet 2 E type core 3 I type core

Claims (7)

[Claims] 1. An inductance element in which a permanent magnet for applying a magnetic bias to a magnetic core gap is disposed, wherein said permanent magnet has an electric resistance of 0.01 to 0.05 Ωcm and 0 ° C.
An inductance element characterized by being a heat-resistant bonded magnet having an irreversible demagnetization rate change of from 2 to 120 ° C within 2%. 2. The bonded magnet is of the RTB-Nb type (where R is at least one kind of rare earth element including Y,
Is Fe or Fe partially substituted with Co and / or Ni)
2. The inductance element according to claim 1, wherein the magnet element is a rare-earth bonded magnet in which a magnet powder is bonded with a binder of a polymer, a pure metal, or an alloy. 3. The bonded magnet has a composition component of R _α T
A _{100- (α + β + γ)} B β Nb γ, R is any one or more rare earth elements including Y, T is obtained by substituting Fe or partly Co and / or Ni Fe Wherein the α, β, and γ are rare earth bonded magnets in which a rare earth magnetic powder having an atomic percentage in the following range is bound with a polymer, a pure metal, or a binder of any of alloys. Item 3. An inductance element according to claim 1. 8 ≦ α ≦ 15 4 ≦ β ≦ 8 0.1 ≦ γ ≦ 2 4. The bonded magnet is an RTMBN system (R
Is any one or more of rare earth elements including Y,
T is Fe or F partially substituted with Co and / or Ni.
e and M are Al, Ti, V, Cr, Mn, Cu, Ga, Z
any one of r, Nb, Mo, Hf, Ta, W or 2
2. The inductance element according to claim 1, wherein the magnet element is a rare earth bonded magnet in which a magnet powder is bonded with a binder of a polymer, a pure metal, or an alloy. 5. The bonded magnet has a component composition of R_αT
_{100- (α + β + γ + δ)}M _βB_γN_δAnd the R
Is one or more of the rare earth elements including Y
And T represents Fe or a part thereof on Co and / or Ni.
Replaced Fe, M is Al, Ti, V, Cr, Mn, C
u, Ga, Zr, Nb, Mo, Hf, Ta, W
Or one or more kinds thereof, wherein the α, β, γ, and δ are
Powder of rare earth magnet material in the following range in atomic percentage
A polymer, pure metal or alloy binder
Characterized in that they consist of rare-earth bonded magnets
5. The inductance element according to claim 1, wherein 5 ≦ α ≦ 18 1 ≦ β ≦ 50 0.1 ≦ γ ≦ 5 4 ≦ δ ≦ 30 6. Atomic% of R component of rare earth bonded magnet
The inductance element according to any one of claims 1 to 5, wherein the above is Sm. 7. The rare earth magnetic powder has an average particle size of 10 to 12.
The inductance element according to any one of claims 1 to 6, wherein the inductance element is within a range of 0 µm.