Armature coil and armature

1. An armature coil comprising a plurality of unit coils to be stored in slots of an armature, wherein

each unit coil includes a plurality of strands each of which is transposed, and the strands extend out from the slot at both ends in an axial direction of the slot and are electrically connected to form coil end portions,

each of the strands forming each unit coil is configured such that,

transposition by transposition angle 540 degrees is made between both ends in the axial direction in the slot, and

where the strand is divided into a first section having a first width in the axial direction, a second section having a second width in the axial direction, and a third section having a third width in the axial direction, continuously in the axial direction from one end side to another end side in the axial direction in the slot, transposition by transposition angle 180 degrees is made in each of the first section, the second section, and the third section, and transposition by a first transposition angle θ is made at the coil end portions,

each strand has, in each section in the slot, a change portion in which a change rate of transposition of the strand is changed, and

an axial-direction middle point of the change portion in each section of a first strand which is at least one of the strands of each unit coil is located between a position at transposition angle 90 degrees and a position obtained by adding the first transposition angle of the first strand to the transposition angle 90 degrees, in each section.

2. The armature coil according to claim 1 , wherein

the change rate of transposition in the change portion in the first section is set to be smaller than a value obtained by dividing 180 degrees by the first width,

the change rate of transposition in the change portion in the second section is set to be smaller than a value obtained by dividing 180 degrees by the second width, and

the change rate of transposition in the change portion in the third section is set to be smaller than a value obtained by dividing 180 degrees by the third width.

3. The armature coil according to claim 2 , wherein

the first strand is, of the strands forming the unit coil, the strand located on a radially outermost side or a radially innermost side at both ends in the axial direction of the slot, and

the axial-direction middle point of the change portion in each section of the first strand is located at a position of ((the transposition angle 90 degrees in each section+the first transposition angle θ/2)±a transposition angle corresponding to a thickness in a radial direction of the strand).

4. The armature coil according to claim 2 , wherein

the first width, the second width, and the third width are set so as to have a relationship of the second width=the first width+the third width.

5. The armature coil according to claim 2 , wherein

the change rate of transposition in the change portion in each section is greater than 0.

6. The armature coil according to claim 2 , wherein

the change rate of transposition in the change portion in each section is 0.

7. The armature coil according to claim 1 , wherein

the unit coil is formed by layering the strands a number of which is Y in a radial direction, and

the number Y and the first transposition angle θ of the first strand are set to such values that a value of Y×(180+θ)/360 becomes an integer.

8. The armature coil according to claim 7 , wherein

the number Y is 54, and

the first transposition angle θ of the first strand is set to 60 degrees±10 degrees or 90 degrees±10 degrees.

9. The armature coil according to claim 1 , wherein

a fourth width in the axial direction of the change portion is set in accordance with a value of induced voltage among the strands at the coil end portions.

10. An armature comprising:

a core having the slots; and

the armature coil according to claim 1 ,

the armature being formed by arranging the armature coil in the slots of the core.

11. The armature coil according to claim 3 , wherein

the first width, the second width, and the third width are set so as to have a relationship of the second width the first width+the third width.

12. The armature coil according to claim 3 , wherein

the change rate of transposition in the change portion in each section is greater than 0.

13. The armature coil according to claim 4 , wherein

the change rate of transposition in the change portion in each section is greater than 0.

14. The armature coil according to claim 11 , wherein

the change rate of transposition in the change portion in each section is greater than 0.

15. The armature coil according to claim 3 , wherein

the change rate of transposition in the change portion in each section is 0.

16. The armature coil according to claim 4 , wherein

the change rate of transposition in the change portion in each section is 0.

17. The armature coil according to claim 11 , wherein

the change rate of transposition in the change portion in each section is 0.

18. The armature coil according to claim 2 , wherein

the unit coil is formed by layering the strands a number of which is Y in a radial direction, and

the number Y and the first transposition angle θ of the first strand are set to such values that a value of Y×(180+θ)/360 becomes an integer.

19. The armature coil according to claim 3 , wherein

the unit coil is formed by layering the strands a number of which is Y in a radial direction, and

the number Y and the first transposition angle θ of the first strand are set to such values that a value of Y×(180+θ)/360 becomes an integer.

20. The armature coil according to claim 4 , wherein

the unit coil is formed by layering the strands a number of which is Y in a radial direction, and

the number Y and the first transposition angle θ of the first strand are set to such values that a value of Y×(180+θ)/360 becomes an integer.