An inductor according to an embodiment of the present invention comprises: a first magnetic body having a toroidal shape, and including a ferrite; and a second magnetic body disposed on an outer circumferential surface or an inner circumferential surface of the first magnetic body, wherein the second magnetic body includes: resin material and a plurality of layers of metal ribbons wound along the circumferential direction of the first magnetic body, wherein the resin material comprises a first resin material disposed to cover an outer surface of the plurality of layers of metal ribbons, and a second resin material disposed in at least a part of a plurality of layers of interlayer spaces.

A method for manufacturing a wound magnetic core of a nanocrystalline soft magnetic alloy ribbon, the method including: a first heat treatment step of subjecting a wound magnetic core, which is formed by winding an amorphous soft magnetic alloy ribbon capable of nanocrystallization, to a heat treatment at a temperature that is 300° C. or higher and below a crystallization start temperature, with a first inner shape correction jig for holding the wound magnetic core in a non-circular shape placed in an internal space of the wound magnetic core; and a second heat treatment step of subjecting the wound magnetic core to a heat treatment for nanocrystallization at a temperature equal to or higher than the crystallization start temperature, with the first inner shape correction jig removed and with at least one second inner shape correction jig placed in the internal space of the wound magnetic core, wherein: a cross section of the second inner shape correction jig perpendicular to a direction in which the second inner shape correction jig extends is smaller than a cross section of the first inner shape correction jig perpendicular to a direction in which the first inner shape correction jig extends; and a magnetic field is applied to the wound magnetic core over a partial period of the second heat treatment step.

A power conversion apparatus (1) is used so as to be connected to three voltage units. The power conversion apparatus includes three power-conversion circuit units and a transformer (4). The three power-conversion circuit units are respectively connected to voltage units that differ from one another. Three coils (5) of the transformer (4) are connected to power-conversion circuit units that differ from one another. The three coils (5) are magnetically coupled with one another. The three coils (5) are arranged so as to be arrayed in a coil axial direction (z). One of the voltage units is a high-voltage battery. Among the coils other than a high-voltage battery-side coil (51) that is connected to the high-voltage battery, the coil (5) of which a power value that flows thereto is largest is arranged in a position that is adjacent to the high-voltage battery-side coil (51).

A wound core (10) in which, in a laminating direction, when the surface roughness of a steel sheet portion in a direction connecting a center in a sheet thickness direction of a grain-oriented electrical steel sheet (1) positioned on the innermost periphery of the wound core among the laminated grain-oriented electrical steel sheets (1) and a center in the sheet thickness direction of the grain-oriented electrical steel sheet (1) positioned on the outermost periphery of the wound core (10) is Ral, and the surface roughness of the grain-oriented electrical steel sheet (1) in a direction parallel to a longitudinal direction on an end surface of a planar portion (4) of the laminated grain-oriented electrical steel sheet (1) is Rac, a ratio Ral/Rac between Rat and Rac satisfies the relationship of 1.5≤Ral/Rac≤12.0.

A wound core (10) in which, in a laminating direction, when the surface roughness of a steel sheet portion in a direction connecting a center in a sheet thickness direction of a grain-oriented electrical steel sheet (1) positioned on the innermost periphery of the wound core among the laminated grain-oriented electrical steel sheets (1) and a center in the sheet thickness direction of the grain-oriented electrical steel sheet (1) positioned on the outermost periphery of the wound core (10) is Ral, and the surface roughness of the grain-oriented electrical steel sheet (1) in a direction parallel to a longitudinal direction on an end surface of a planar portion (4) of the laminated grain-oriented electrical steel sheet (1) is Rac, a ratio Ral/Rac between Rat and Rac satisfies the relationship of 1.5≤Ral/Rac≤12.0.

An iron core including a laminate of a plurality of fixed electromagnetic steel sheets, a laminate of alloy thin strips which is sandwiched between the laminate of the electromagnetic steel sheets, a fastening mechanism which penetrates the laminates of electromagnetic steel sheets and alloy thin strips, and a fixing base. The laminate of alloy thin strips reduces compressive and torsional forces acting on the laminate of alloy thin strips by using the iron core having a structure in which upper and lower portions of a laminate of alloy thin strips having nanocrystal grains are sandwiched together with laminates of amorphous alloy thin strips. Furthermore, a motor including a rotor and the above-described iron core is used.

An iron core including a laminate of a plurality of fixed electromagnetic steel sheets, a laminate of alloy thin strips which is sandwiched between the laminate of the electromagnetic steel sheets, a fastening mechanism which penetrates the laminates of electromagnetic steel sheets and alloy thin strips, and a fixing base. The laminate of alloy thin strips reduces compressive and torsional forces acting on the laminate of alloy thin strips by using the iron core having a structure in which upper and lower portions of a laminate of alloy thin strips having nanocrystal grains are sandwiched together with laminates of amorphous alloy thin strips. Furthermore, a motor including a rotor and the above-described iron core is used.

In a method for manufacturing lamination stacks of controlled height in a tool, starting material is provided as continuous strip delivered from a coil or as an individual sheet. Laminations are punched from the starting material in several punching steps to a required contour of the laminations. A heat-curing adhesive is applied onto the laminations prior to performing a last punching step. The laminations are combined to a lamination stack. The laminations of the lamination stack are partially or completely heated in a lamination storage. The adhesive is liquefied by heating the lamination stack to build up adhesion and then solidified. Curing the adhesive at the liquefying temperature or solidifying the adhesive in the tool by cooling and subsequently heating the adhesive to a temperature below the liquefying temperature is possible so that the adhesive does not melt but undergoes further curing resulting in higher temperature stability.

In a method for manufacturing lamination stacks of controlled height in a tool, starting material is provided as continuous strip delivered from a coil or as an individual sheet. Laminations are punched from the starting material in several punching steps to a required contour of the laminations. A heat-curing adhesive is applied onto the laminations prior to performing a last punching step. The laminations are combined to a lamination stack. The laminations of the lamination stack are partially or completely heated in a lamination storage. The adhesive is liquefied by heating the lamination stack to build up adhesion and then solidified. Curing the adhesive at the liquefying temperature or solidifying the adhesive in the tool by cooling and subsequently heating the adhesive to a temperature below the liquefying temperature is possible so that the adhesive does not melt but undergoes further curing resulting in higher temperature stability.

A method of manufacturing a laminated iron core includes: inserting a plurality of electrical steel strips in a superposed state to feed rolls including a pair of upper and lower feed rolls that are driven by a drive device to feed the electrical steel strips in a superposed state into a die having a plurality of punching processes in sequence; joining a part or all of the superposed electrical steel strips together before entering the die or at an upstream stage portion of the die after feeding out the electrical steel strips from the pair of upper and lower feed rolls; and punching simultaneously the plurality of electrical steel strips in a superposed state in the die.