Bobbin, winding apparatus and coil

A bobbin of a split-winding type comprising:

• a winding core on which a wire rod is wound in a circumferential direction of the winding core;
• multiple partitioning walls formed at an outer peripheral surface of the winding core in such a manner that each of the partitioning walls extends in a radial-outward direction, the partitioning walls being arranged in an axial direction of the winding core so as to define multiple winding areas arranged in the axial direction of the winding core;
• and
• a groove having a V-shape formed in each of the partitioning walls, through which the wire rod passes from a first winding area to a second winding area neighboring to the first winding area,
• wherein the groove has a first guide wall surface and a second guide wall surface, which are opposed to each other in the circumferential direction,
• wherein the first guide wall surface is inclined in the axial direction with respect to the first winding area and directly faces the first winding area, the second guide wall surface is inclined in the axial direction with respect to the second winding area and directly faces the second winding area,
• wherein the first guide wall surface is inclined in the circumferential direction such that the first guide surface comes closer to the second guide wall surface in the circumferential direction from a winding-start side to a winding-end side and the first guide surface comes closer to the second guide wall surface in the axial direction from a stride-start side to a stride-end side, and
• wherein the second guide wall surface extends in the circumferential direction such that the second guide surface goes away from the first guide wall surface in the axial direction from the stride-start side to the stride-end side.