US-12626845-B2 - Wound magnetic core, alloy core, and method for manufacturing wound magnetic core

Abstract

Provided herein is a method for manufacturing a wound magnetic core of a nanocrystalline soft magnetic alloy ribbon.

Inventors

• Kazuhiro Hagiwara

Assignees

• PROTERIAL, LTD.

Dates

Publication Date

20260512

Application Date

20230630

Priority Date

20190205

Claims (4)

1. 1 . A wound magnetic core of a nanocrystalline soft magnetic alloy ribbon, wherein the wound magnetic core has a non-circular shape, and an impedance relative magnetic permeability μrz at 100 kHz of the wound magnetic core is 45000 or more; and wherein the wound magnetic core has no portion where the nanocrystalline soft magnetic alloy ribbon is spaced apart by 0.1t or more from a nanocrystalline soft magnetic alloy ribbon that is adjacent thereto in a stacking direction, wherein t is a thickness of the wound magnetic core in the stacking direction, and wherein the nanocrystalline soft magnetic alloy ribbon has a composition represented by (Fe 1-a M a ) 100-x-y-z-α-β-γ Cu x Si y B z M′ α M″ β X γ (atom %), where M is at least one element selected from Co and Ni, M′ is at least one element selected from Nb, Mo, Ta, Ti, Zr, Hf, V, Cr, Mn and W, M″ is at least one element selected from Al, platinum group elements, Sc, rare earth elements, Zn, Sn and Re, and X is at least one element selected from C, Ge, P, Ga, Sb, In, Be and As, a, x, y, z, α, β and γ, which define the composition ratio, can satisfy the following relationships; 0≤a<0.5, 0.1≤x≤3, 10≤y≤20, 5≤z≤10, 0.1≤α≤5, 0≤β≤10, and 0≤γ≤10.
2. 2 . The wound magnetic core of a nanocrystalline soft magnetic alloy ribbon according to claim 1 , wherein the wound magnetic core has a racetrack shape or has a racetrack shape with a concave/convex portion along at least one straight portion of the racetrack shape.
3. 3 . The wound magnetic core of a nanocrystalline soft magnetic alloy ribbon according to claim 1 , wherein in a state where an AC magnetic field of frequency f=10 kHz and amplitude H=0.05 A/m is applied, the wound magnetic core has a relative magnetic permeability μ (10 kHz) of 80,000 or more, as measured at room temperature, a direct-current BH loop squareness ratio Br/Bm of 50% or less and a coercive force of 1.1 A/m or less.
4. 4 . An alloy core comprising: the wound magnetic core of a nanocrystalline soft magnetic alloy ribbon according to claim 1 ; and a resin with which the wound magnetic core is impregnated.

Description

TECHNICAL FIELD The present disclosure relates to a non-circular wound magnetic core obtained by winding a soft magnetic alloy ribbon made of a nanocrystalline alloy, an alloy core, and a method for manufacturing a wound magnetic core. BACKGROUND ART An increase in the frequency of inverters following an increase in the performance of power semiconductor devices makes it possible to improve the current-voltage control capacity, but high frequency leakage current caused by common mode voltage generated by inverters has become a problem. As a means for suppressing this, common mode choke coils have been used. Common mode choke coils have a magnetic core made of a soft magnetic material. Patent Document No. 1 discloses that a magnetic core made from a ribbon of an Fe-based or Co-based nanocrystalline alloy is suitable as a magnetic core for use in these. A nanocrystalline alloy exhibits a higher saturation magnetic flux density than a permalloy or a Co-based amorphous alloy, and has a higher magnetic permeability than an Fe-based amorphous alloy. For example, Patent Document No. 2 discloses typical compositions of nanocrystalline alloys. A typical example of a method for manufacturing a magnetic core using a nanocrystalline alloy includes a step of producing an amorphous alloy ribbon by quenching a molten metal of a material alloy having an intended composition, a step of winding the amorphous alloy ribbon into a ring-shaped wound magnetic core, and a step of crystallizing the amorphous alloy ribbon by heat treatment to obtain a magnetic core having a nanocrystalline structure. With magnetic cores made of nanocrystalline alloys, it is possible to significantly change the magnetic properties such as the magnetic permeability p and the squareness ratio by the temperature profile during the heat treatment or by applying a magnetic field in a particular direction during the heat treatment. For example, Patent Document No. 3 describes a magnetic core having a high magnetic permeability and a low squareness ratio, wherein the magnetic permeability p (50 Hz-1 kHz) is 70,000 or more and the squareness ratio is 30% or less, realized by controlling the direction of magnetic field application to be the height direction or the radial direction of the magnetic core. Typically, magnetic cores made of nanocrystalline alloys are often circular in shape. A circular magnetic core is manufactured by circularly winding an amorphous alloy ribbon into a ring-shaped wound magnetic core, and then performing a heat treatment that involves nanocrystallization (hereinafter, nanocrystallization heat treatment). On the other hand, depending on the space in which the magnetic core is used, there may be a demand for a non-circular magnetic core such as a rectangular or elliptical magnetic core. When manufacturing a non-circular magnetic core, the nanocrystallization heat treatment is performed after the inner circumference of a wound magnetic core is straightened to a non-circular shape by a non-circular inner shape correction jig. Patent Document No. 4 discloses a nanocrystallization heat treatment method, including winding an amorphous alloy ribbon around a core, then relieving the stress in the ribbon through a primary heat treatment of holding the ribbon at a temperature below the crystallization start temperature, removing the core, and then performing a secondary heat treatment for nanocrystallization of the ribbon at a temperature equal to or higher than the crystallization start temperature. According to Patent Document No. 4, this method can suppress the deterioration of magnetic properties due to the stress generated during heat treatment. CITATION LIST Patent Literature Patent Document No. 1: Japanese Patent No. 2501860Patent Document No. 2: Japanese Patent Publication for Opposition No. 4-4393Patent Document No. 3: Japanese Laid-Open Patent Publication No. 7-278764Patent Document No. 4: Japanese Laid-Open Patent Publication No. 1-247557 SUMMARY OF INVENTION Technical Problem In the application of electric vehicles, etc., a wound magnetic core such as a common mode choke coil is in some cases installed inside a device where many wires and electronic parts are placed. In such a case, the installed wound magnetic core may be designed in a shape that does not spatially interfere with these parts. Specifically, there may be a demand for a non-circular wound magnetic core. In recent years, such non-circular wound magnetic cores have been demanded increasingly. The present disclosure provides a wound magnetic core made of a nanocrystalline soft magnetic alloy ribbon that has a non-circular shape and yet achieves impedance characteristics equivalent to those achieved with a circular shape, an alloy core and a method for manufacturing a wound magnetic core. Solution to Problem A method for manufacturing a wound magnetic core of a nanocrystalline soft magnetic alloy ribbon according to one embodiment of the present disclosure includes: a