Armature and motor

1. An armature comprising:

a core that includes a ring portion and a plurality of tooth portions, wherein each of the plurality of tooth portions extends radially outward from an outer peripheral part of the ring portion, and a plurality of slots is defined such that each slot is formed between corresponding adjacent two of the plurality of tooth portions; and

a plurality of windings, each of which is wound around at least two of the plurality of tooth portions to form at least two wound parts of the winding, wherein:

a crossover of each winding, which connects between corresponding two of the at least two wound parts, is placed on one axial side of the ring portion;

a crossover relief space is axially recessed in an end surface of the ring portion on the one axial side of the ring portion at a location radially inward of an outer peripheral surface of the ring portion; and

at least a portion of each crossover is received in the crossover relief space, wherein

a guide wall axially protrudes in the core on the one axial side of the ring portion such that the guide wall is radially inwardly spaced from an inner peripheral surface of the ring portion to radially define the crossover relief space all around the guide wall between an outer peripheral surface of the guide wall and the inner peripheral surface of the ring portion; and

each crossover is held along the outer peripheral surface of the guide wall.

2. The armature according to claim 1 , wherein an axial position of an outermost part of all the crossovers in an axial direction of the ring portion is the same as or axially inward of an axial position of an outermost part of all the wound parts in the axial direction of the ring portion on the one axial side of the ring portion.

3. The armature according to claim 1 , wherein:

a plurality of radial recesses is formed in an inner peripheral surface of the ring portion to reduce a radial wall thickness of the ring portion at each of the plurality of radial recesses in comparison to a radial wall thickness of the rest of the ring portion; and

each of the plurality of radial recesses is located radially inward of a corresponding one of the plurality of tooth portions.

4. The armature according to claim 3 , wherein:

a number of the plurality of radial recesses is the same as a number of the plurality of tooth portions; and

each of the plurality of radial recesses receives the crossover that is connected to the wound part, which is wound around the corresponding one of the plurality of tooth portions.

5. The armature according to claim 1 , wherein:

the guide wall is annular in a circumferential direction of the ring portion;

an increased diameter portion is provided to the guide wall at a location that is on one side of the respective crossovers where a protruding end of the guide wall is located; and

an outer diameter of the increased diameter portion is larger than that of an adjacent part of the guide wall, which is adjacent to the increased diameter portion.

6. The armature according to claim 5 , wherein:

the increased diameter portion is formed as a flange member, which is formed separately from the guide wall; and

the flange member is held to the guide wall by an engaging means.

7. The armature according to claim 6 , wherein the engaging means includes: at least one engaging portion that is formed in the flange member;

at least one engaging portion that is formed in the core to engage with the at least one engaging portion of the flange member.

8. The armature according to claim 1 , wherein at least one cooling hole penetrates through a bottom portion of the crossover relief space at the core in the axial direction of the ring portion.

9. A motor comprising:

the armature of claim 1 ;

a rotor that is rotatably placed radially outward of the armature; and

a fan that is connected to the rotor to rotate integrally with the rotor.