Apparatus and method for winding multi-layer coil in trapezoidal winding space

An apparatus for winding a multi-layer coil in a winding space of a bobbin having a center pillar, a small flange connected to one end of the center pillar and a large flange connected to the other end of the center pillar, the winding space being defined outside the center pillar between both flanges and having a trapezoidal cross-section in a plane cut through a center axis of the center pillar, the winding apparatus comprising:

• a rotating device for rotating the bobbin around the center axis thereof;
• a wire feeder for supplying a wire forming the multi-layer coil, the wire feeder being reciprocally moved in a direction parallel to the center axis for winding each layer of the coil;
• and
• a position setter for setting a turning position where a layer of the coil wound from the large flange toward the small flange is switched to a next layer wound from the small flange toward the large flange, wherein:
• inner layers of the coil are wound around the center pillar in a space between the small flange and the large flange until a height of the inner layers reaches a height of the small flange, and thereafter outer lavers are wound on the inner lavers while shifting the turning position toward the large flange by predetermined wire-pitches for each layer, thereby forming the multi-layer coil encompassed within the winding space having the trapezoidal cross-section, wherein:
• the position setter is a single unit that includes a plurality of setting steps, the position setter being fixedly positioned so that each setting step corresponds to the turning position of each layer.

A of winding a multi-layer coil in a winding apparatus of a bobbin having a center pillar, a small flange connected to one end of the center pillar and a large flange connected to the other end of the center pillar, the winding space being defined outside the center pillar between both flanges and having a trapezoidal cross-section in a plane cut through a center axis of the center pillar, the winding method comprising:

• winding a wire around the center pillar of the bobbin in an inner space between the small flange and the large flange, forming inner layers of the wire, until a height of the inner layers reaches a height of the small flange;
• and
• further winding the wire around the inner layers, forming outer layers of the wire, while gradually decreasing, layer by layer, number of wire-turns included in each layer by setting a turning position where each layer moves up to a next layer and by shifting the turning position toward the large flange, thereby forming the multi-layer coil encompassed within the winding apparatus having the trapezoidal cross-section, wherein:
• the turning positions of all of the outer layers are set by a fixed single position setter that includes a plurality of setting steps, each step corresponding to the turning position of each outer layer.