Reactor, converter, and power conversion device

A reactor comprising:

• a coil including a first winding portion;
• and
• a magnetic core,
• wherein the magnetic core includes:
• a middle core arranged inside the first winding portion,
• a first end core facing a first end face of the first winding portion,
• a second end core facing a second end face of the first winding portion,
• a first side core that is arranged outward of a first side face of the first winding portion and connects the first end core and the second end core, and
• a second side core that is arranged outward of a second side face of the first winding portion and connects the first end core and the second end core,
• at least one of the first side core and the second side core includes an inward recessed portion provided in an inward face that faces the first winding portion in a Y direction,
• in a plan view of the magnetic core from a Z direction, at least a portion of the inward recessed portion is overlapped with a range corresponding to a length of the first winding portion in an X direction,
• in a plan view of the magnetic core from the Z direction, the width of the inward recessed portion in the X direction is 43% or more and 54% or less of a length of the middle core in the X direction, and the depth of the inward recessed portion in the Y direction is 27% or more and 36% or less of a length of the first side core or the second side core in the Y direction,
• the X direction is a direction conforming to an axial direction of the middle core,
• the Y direction is a direction in which the middle core, the first side core, and the second side core are side-by-side,
• the Z direction is a direction orthogonal to the X direction and the Y direction, and wherein the first side core and the second side core are each a compact made of a composite material in which a soft magnetic powder is dispersed in a resin,
• wherein the magnetic core comprises a plurality of core pieces combined together, wherein at least one of the core pieces constitutes the middle core and is a powder compact formed by pressure molding a raw material powder containing the soft magnetic powder.