Electric motor having a polygon stator
An electric motor has a polygon stator core. The polygon stator core includes yoke portions and teeth extending inwardly from the yoke portions. A winding slot is formed between adjacent teeth. Adjacent yoke portions are interconnected by a connecting portion. The winding slots include first winding slots and second winding slots of different shapes. The ratio of the area of a first winding slot to the area of a second winding slot is greater than or equal to 0.9 but less than or equal to 1.1. By changing the shape of the stator core, the size of the winding slots may be increased without increasing the radial dimension of the motor.
1. An electric motor comprising a stator having a polygon stator core and a rotor rotatable relative to the stator and having a plurality of magnetic poles,
wherein the polygon stator core comprises:
a plurality of yoke portions and connecting portions interconnecting adjacent yoke portions to form a polygon, adjacent yoke portions having a same shape and size;
a plurality of teeth extending inwardly from the yoke portions, adjacent teeth having different shapes and sizes,
winding slots respectively formed between adjacent teeth, the winding slots comprising a plurality of first winding slots and a plurality of second winding slots, the first winding slots and the second winding slots have different shapes, and the ratio of the area of one of the first winding slots to the area of one of the second winding slots is greater than or equal to 0.9 but less than or equal to 1.1;
wherein two of the second winding slots circumferentially adjacent to each other are disposed between opposite first winding slots, each of said opposite first winding slot is disposed between a pair of said circumferentially adjacent second winding slots.
2. The motor of claim 1 , wherein the yoke portions of the stator core are connected to form one of a quadrilateral, a square and a hexagon.
3. The motor of claim 2 , wherein each yoke portion of the stator core is straight.
4. The motor of claim 2 , wherein each yoke portion of the stator core is arc-shaped.
5. The motor of claim 2 , wherein the number of the winding slots is an integral multiple of three.
6. The motor of claim 2 , wherein the shape of the winding slot is one of a triangle, rectangle, rhombus and trapezoid.
7. The motor of claim 1 , wherein the connecting portion is one of arcuate, straight and kinked in shape.
8. The motor of claim 1 , wherein the yoke portions of the stator core are connected to form a quadrilateral, and six or twelve teeth are formed along an inner circumferential surface of the stator core.
9. The motor of claim 1 , wherein the plurality of the first winding slots have a first shape, and the plurality of the second winding slots have a second shape, different from the first shape.
10. The motor of claim 1 , wherein the ratio of the number of the magnetic poles to the number of the teeth is 2:3.