Method for manufacturing a transformer

A method for manufacturing a transformer, which comprises the steps of:

• preparing a core, a first coil portion that covers at least part of the core, and a second coil portion disposed so as to cover a periphery of the first coil portion in a first direction perpendicular to a central axis of winding of the first coil portion,
• the first coil portion including a first bobbin and a first coil wound around the first bobbin,
• the second coil portion including a second bobbin and a second coil wound around the second bobbin,
• at least one of the first coil and the second coil being an edgewise coil;
• screwing the first bobbin to the first coil, and screwing the second bobbin to the second coil;
• and
• attaching the second coil portion to an outside of the first coil portion in the first direction, and attaching the core so as to sandwich the first coil portion and the second coil portion in an axial direction of the first coil portion, wherein
• at least one of the first bobbin and the second bobbin includes:
• a tubular bobbin body;
• and
• a plurality of position-limiting protruding portions arranged in a plurality of portions on an outer peripheral surface of the tubular bobbin body and limiting a position of a winding portion of the edgewise coil in an axial direction of the tubular bobbin body,
• the plurality of position-limiting protruding portions include a first position-limiting protruding portion and a second position-limiting protruding portion that are disposed at positions different from each other in the axial direction of the tubular bobbin body, and
• in the screwing step, the edgewise coil is wound around the at least one of the first bobbin and the second bobbin by screwing the at least one of the first bobbin and the second bobbin to the edgewise coil so that:
• the edgewise coil includes:
• a first winding portion that is in pressure contact with the first position-limiting protruding portion toward the second position-limiting protruding portion;
• and
• a second winding portion that is in pressure contact with the second position-limiting protruding portion toward the first position-limiting protruding portion;
• and
• the edgewise coil is in a state of space winding in which individual winding portions from the first winding portion to the second winding portion are spaced apart from each other in the axial direction of the tubular bobbin body.