| 主权项 |
1. An armature comprising:
a core back; a plurality of teeth arranged to extend radially inward or radially outward from the core back; insulators, each of which is arranged to cover a separate one of the teeth; and coils, each of which is defined by a conducting wire wound around a separate one of the insulators; wherein each insulator includes an upper resin member and a lower resin member; the upper resin member includes:
a top plate portion arranged to cover an upper surface of a corresponding one of the teeth;a pair of upper side wall portions, each of which is arranged to extend downward from a separate circumferential end portion of the top plate portion to cover an upper region of a separate one of circumferential side surfaces of the tooth;a pair of first upper decreased thickness portions, each of which is arranged to extend further downward from a lower end portion of a separate one of the upper side wall portions, each of the pair of first upper decreased thickness portions having a circumferential thickness smaller than that of each upper side wall portion; anda first upper rib; the lower resin member includes:
a bottom plate portion arranged to cover a lower surface of the tooth;a pair of lower side wall portions, each of which is arranged to extend upward from a separate circumferential end portion of the bottom plate portion to cover a lower region of a separate one of the circumferential side surfaces of the tooth;a pair of first lower decreased thickness portions, each of which is arranged to extend further upward from an upper end portion of a separate one of the lower side wall portions, each of the pair of first lower decreased thickness portions having a circumferential thickness smaller than that of each lower side wall portion; anda first lower rib; an axial position of each of the first upper decreased thickness portions and the first upper rib is arranged to overlap at least partially with an axial position of each of the first lower decreased thickness portions and the first lower rib; the first upper rib is arranged to project in a circumferential direction from a surface of a corresponding one of the first upper decreased thickness portions toward a corresponding one of the first lower decreased thickness portions; the first lower rib is arranged to project in the circumferential direction from a surface of a corresponding one of the first lower decreased thickness portions toward a corresponding one of the first upper decreased thickness portions; each of the circumferential thickness of each first upper decreased thickness portion and a combined circumferential thickness of the first upper decreased thickness portion and the first upper rib is arranged to decrease with decreasing height or to be uniform; each of the circumferential thickness of each first lower decreased thickness portion and a combined circumferential thickness of the first lower decreased thickness portion and the first lower rib is arranged to decrease with increasing height or to be uniform; a radial width of the first upper rib is arranged to decrease with decreasing height or to be uniform; and a radial width of the first lower rib is arranged to decrease with increasing height or to be uniform. |
