Magnetic core including magnet for magnetic bias and inductor component using the same

• US 6,906,608 B2
• Filed: 05/11/2004
• Issued: 06/14/2005
• Est. Priority Date: 11/30/2000
• Status: Expired due to Term

• Current Assignee: Tokin Corporation (Yageo Corporation)
• Original Assignee: NEC Tokin Corporation (Yageo Corporation)
• Inventors: Ito, Toru, Fujiwara, Teruhiko, Ishii, Masayoshi, Ambo, Tamiko, Hoshi, Haruki, Isogai, Keita
• Primary Examiner(s): Nguyen, Tuyen T.
• Application Number:
  US10/844,014
• Publication Number:
  US 20040207500A1
• Time in Patent Office: 399 Days
• Field of Search: 336/83, 336/110, 336/178, 336211-217, 336233-234, 148/105, 148/108, 148300-301, 428/323, 428/328, 335299-306
• US Class Current: 336/110
• CPC Class Codes: H01F 17/04 with magnetic core
• CPC Class Codes: H01F 2003/103 Magnetic circuits with permanent magnets
• CPC Class Codes: H01F 29/146 Constructional details
• CPC Class Codes: H01F 3/10 Composite arrangements of magnetic circuits
• CPC Class Codes: H01F 3/14 Constrictions; Gaps, e.g. air-gaps in magnetic shunt paths H01F3/12

Abstract

An inductor component according to the present invention includes a magnetic core including at least one magnetic gap having a gap length of about 50 to 10,000 μm in a magnetic path, a magnet for magnetic bias arranged in the neighborhood of the magnetic gap in order to supply magnetic bias from both sides of the magnetic gap, and a coil having at least one turn applied to the magnetic core. The aforementioned magnet for magnetic bias is a bonded magnet containing a resin and a magnet powder dispersed in the resin and having a resistivity of 1 Ω·cm or more. The magnet powder includes a rare-earth magnet powder having an intrinsic coercive force of 5 KOe or more, a Curie point of 300° C. or more, the maximum particle diameter of 150 μm or less, and an average particle diameter of 2.0 to 50 μm m and coated with inorganic glass, and the rare-earth magnet powder is selected from the group consisting of a Sm—Co magnet powder, Nd—Fe—B magnet powder, and Sm—Fe—N magnet powder.

Claims

1. An inductor component comprising:

a magnetic core having at least one magnetic gap, each of which has a gap length of about 50 to 10,000 μ

m in a magnetic path;

a magnet for magnetic bias arranged in the neighborhood of the magnetic gap in order to supply magnetic bias from both sides of the magnetic gap; and

a coil having at least one turn applied to the magnetic core, wherein;

the magnet for magnetic bias is a bonded magnet comprising a resin and a magnet powder dispersed in the resin and having a resistivity of 1 Ω

·

cm or more;

the magnet powder comprising a rare-earth magnet powder having an intrinsic coercive force of 5 KOe or more, a Curie point of 300°

C. or more, a maximum particle diameter of 150 μ

m or less, and an average particle diameter of 2 to 50 μ

m and coated with inorganic glass; and

the rare-earth magnet powder is selected from the group consisting of a Sm—

Co magnet powder, Nd—

Fe—

B magnet powder, and Sm—

Fe—

N magnet powder.

2. The inductor component according to claim 1, wherein the permanent magnet for magnetic bias is molded by die molding.

3. The inductor component according to claim 2, wherein the permanent magnet for magnetic bias has a molding compressibility of 20% or more.

4. The inductor component according to claim 1, wherein the surface of the permanent magnet for magnetic bias is coated with a heat-resistant resin or heat-resistant coating having a heat resistance temperature of 120°

C. or more.

5. The inductor component according to claim 1, wherein the inorganic glass has a softening point of 220°

C. to 550°

C.

6. The inductor component according to claim 1, wherein the content of the inorganic glass is 10% by weight or less.

7. The inductor component according to claim 1, wherein the content of the resin is 20% or more, the resin being at least one selected from the group consisting of polypropylene resins, 6-nylon resins, 12-nylon resins, polyimide resins, polyethylene resins, and epoxy resins.

8. An inductor component to be subjected to a solder reflow treatment, comprising:

a magnetic core having at least one magnetic gap each of which has a gap length of about 50 to 10,000 μ

m in a magnetic path;

a magnet for magnetic bias arranged in the neighborhood of the magnetic gap in order to supply magnetic bias from both sides of the magnetic gap; and

a coil having at least one turn applied to the magnetic core, wherein;

the magnet for magnetic bias is a bonded magnet comprising a resin and a magnet powder dispersed in the resin and having a resistivity of 1 Ω

·

cm or more; and

the magnet powder comprises a Sm—

Co rare-earth magnet powder having an intrinsic coercive force of 10 KOe or more, a Curie point of 500°

C. or more, a maximum particle diameter of 150 μ

m or less, and an average particle diameter of 2.5 to 50 μ

m and coated with inorganic glass.

9. The inductor component according to claim 8, wherein the permanent magnet for magnetic bias is molded by die molding.

10. The inductor component according to claim 9, wherein the permanent magnet for magnetic bias has a molding compressibility of 20% or more.

11. The inductor component according to claim 8, wherein the surface of the permanent magnet for magnetic bias is coated with a heat-resistant resin or heat-resistant coating having a heat resistance temperature of 270°

C. or more.

12. The inductor component according to claim 8, wherein the SmCo rare-earth magnet powder is an alloy powder represented by Sm(Co_balFe_{0.15 to 0.25}Cu_{0.05 to 0.06}Zr_{0.02 to 0.03})_{7.0 to 8.5}.

13. The inductor component according to claim 8, wherein the inorganic glass has a softening point of 220°

C. to 500°

C.

14. The inductor component according to claim 8, wherein the content of the inorganic glass is 10% by weight or less.

15. The inductor component according to claim 8, wherein the content of the resin is 30% by volume or more, and the resin being at least one selected from the group consisting of polyimide resins, poly(amide-imide) resins, epoxy resins, poly(phenylene sulfide) resins, silicone resins, polyester resins, aromatic polyamide resins, and liquid crystal polymers.

16. An inductor component comprising:

a magnetic core comprising at least one magnetic gap having a gap length of about 500 μ

m or less in a magnetic path;

a magnet for magnetic bias arranged in the neighborhood of the magnetic gap in order to supply magnetic bias from both sides of the magnetic gap; and

a coil having at least one turn applied to the magnetic core, wherein;

the magnet for magnetic bias is a bonded magnet comprising a resin and a magnet powder dispersed in the resin and having a resistivity of 0.1 Ω

·

cm or more and a thickness of 500 μ

m or less;

the magnet powder comprises a rare-earth magnet powder having an intrinsic coercive force of 5 KOe or more, a Curie point of 300°

C. or more, a maximum particle diameter of 150 μ

m or less, and an average particle diameter of 2.0 to 50 μ

m; and

the rare-earth magnet powder is selected from the group consisting of a Sm—

Co magnet powder, Nd—

Fe—

B magnet powder, and Sm—

Fe—

N magnet powder, and is coated with inorganic glass.

17. The inductor component according to claim 16, wherein the permanent magnet for magnetic bias is molded from a mixture of the resin and magnet powder by a film making method, such as a doctor blade method and printing method.

18. The inductor component according to claim 16, wherein the permanent magnet for magnetic bias has a molding compressibility of 20% or more.

19. The inductor component according to claim 16, wherein the surface of the permanent magnet for magnetic bias is coated with a heat-resistant resin or heat-resistant coating having a heat resistance temperature of 120°

C. or more.

20. The inductor component according to claim 16, wherein the inorganic glass has a softening point of 220°

C. to 500°

C.

21. The inductor component according to claim 16, wherein the content of the inorganic glass is 10% by weight or less in the permanent magnet.

22. The inductor component according to claim 16, wherein the content of the resin is 20% or more, and the resin is at least one selected from the group consisting of polypropylene resins, 6-nylon resins, 12-nylon resins, polyimide resins, polyethylene resins, and epoxy resins.

23. An inductor component to be subjected to a solder reflow treatment, comprising:

a magnetic core having at least one magnetic gap each of which has a gap length of about 500 μ

m or less in a magnetic path;

a magnet for magnetic bias arranged in the neighborhood of the magnetic gap in order to supply magnetic bias from both sides of the magnetic gap; and

a coil having at least one turn applied to the magnetic core, wherein;

the magnet for magnetic bias is a bonded magnet comprising a resin and a magnet powder dispersed in the resin and having a resistivity of 0.1 Ω

·

cm or more and a thickness of 500 μ

m or less; and

the magnet powder comprises a Sm—

Co rare-earth magnet powder having an intrinsic coercive force of 10 KOe or more, a Curie point of 500°

C. or more, a maximum particle diameter of 150 μ

m or less, and an average particle diameter of 2.5 to 50 μ

m and coated with inorganic glass.

24. The inductor component according to claim 23, wherein the permanent magnet for magnetic bias is molded from a mixture of the resin and magnet powder by a film making method, such as a doctor blade method and printing method.

25. The inductor component according to claim 23, wherein the permanent magnet for magnetic bias has a molding compressibility of 20% or more.

26. The inductor component according to claim 23, wherein the inorganic glass has a softening point of 220°

C. to 500°

C.

27. The inductor component according to claim 23, wherein the content of the inorganic glass is 10% by weight or less in the permanent magnet.

28. The inductor component according to claim 23, wherein the surface of the permanent magnet for magnetic bias is coated with a heat-resistant resin or heat-resistant coating having a heat resistance temperature of 270°

C. or more.

29. The inductor component according to claim 23, wherein the SmCo rare-earth magnet powder is an alloy powder represented by Sm(Co_balFe_{0.15 to 0.25}Cu_{0.05 to 0.06}Zr_{0.02 to 0.03})_{7.0 to 8.5}.

30. The inductor component according to claim 23, wherein the content of the resin is 30% by volume or more, the resin being at least one selected from the group consisting of polyimide resins, poly(amide-imide) resins, epoxy resins, poly(phenylene sulfide) resins, silicone resins, polyester resins, aromatic polyamide resins, and liquid crystal polymers.