Method of manufacturing armature

1. A method of manufacturing an armature that includes an armature core having a plurality of slots extending in a central axis direction, and a coil unit in which distal ends of a plurality of segment conductors disposed to face each other in the central axis direction are bonded with a bonding agent containing a conductive material, the method comprising:

a step of placing the bonding agent on bonding surfaces of the distal ends of the plurality of segment conductors;

a step of increasing a viscosity of the bonding agent placed on the distal ends after the step of placing the bonding agent;

a step of placing the plurality of segment conductors on the armature core after the step of increasing the viscosity of the bonding agent such that the bonding surface of the distal end of one segment conductor of the plurality of segment conductors and the bonding surface of the distal end of another segment conductor of the plurality of segment conductors face each other; and

a step of bonding the distal ends to each other with the conductive material of the bonding agent after the step of placing the plurality of segment conductors on the armature core.

2. The method of manufacturing an armature according to claim 1 , wherein the step of increasing the viscosity of the bonding agent is a step of increasing the viscosity of the bonding agent, by volatilizing at least a part of a volatile agent contained in the bonding agent.

3. The method of manufacturing an armature according to claim 2 , wherein the step of increasing the viscosity of the bonding agent is a step of increasing the viscosity of the bonding agent, by volatilizing at least a part of the volatile agent contained in the bonding agent by heating the bonding agent.

4. The method of manufacturing an armature according to claim 3 , wherein:

the step of increasing the viscosity of the bonding agent is a step of increasing the viscosity of the bonding agent, by volatilizing at least a part of the volatile agent contained in the bonding agent by heating the bonding agent to a temperature in a volatilization temperature range in which the volatile agent volatilizes; and

the step of bonding the distal ends to each other is a step of bonding the distal ends to each other by heating the bonding agent to a temperature in a bonding temperature range higher than the volatilization temperature range.

5. The method of manufacturing an armature according to claim 3 , wherein:

the step of placing the plurality of segment conductors on the armature core is a step of placing the plurality of segment conductors on the armature core such that the distal end of the one segment conductor and the distal end of the other segment conductor face each other in the central axis direction and such that a first surface of the distal end of the one segment conductor and a second surface of the distal end of the other segment conductor face each other in a radial direction of the armature core; and

the step of bonding the distal ends to each other is a step of bonding the distal ends to each other, by heating the bonding agent while pressing the first surface and the second surface against each other in the radial direction of the armature core.

6. The method of manufacturing an armature according to claim 2 , wherein:

the bonding agent contains the conductive material, the volatile agent, and a covering material that covers at least a part of a periphery of the conductive material;

the step of increasing the viscosity of the bonding agent is a step of increasing the viscosity of the bonding agent, by volatilizing the volatile agent contained in the bonding agent; and

the step of bonding the distal ends to each other is a step of bonding the distal ends to each other with the conductive material remaining between the distal ends, by volatilizing the covering material contained in the bonding agent.

7. The method of manufacturing an armature according to claim 1 , wherein the step of increasing the viscosity of the bonding agent is a step of increasing the viscosity of the bonding agent, by heating the bonding agent.

8. The method of manufacturing an armature according to claim 1 , wherein the step of increasing the viscosity of the bonding agent is a step of increasing the viscosity of the bonding agent.

9. The method of manufacturing an armature according to claim 8 , further comprising:

a step of forming coil assemblies by arranging the plurality of segment conductors with the bonding agent placed on the segment conductors in an annular shape, before the step of placing the plurality of segment conductors on the armature core; wherein:

the step of increasing the viscosity of the bonding agent is a step of increasing the viscosity of the bonding agent, before the step of forming the coil assemblies; and

the step of placing the plurality of segment conductors on the armature core is a step of placing the plurality of segment conductors on the armature core, by placing the coil assemblies on the armature core.

10. The method of manufacturing an armature according to claim 1 , wherein the step of placing the bonding agent is a step of applying the bonding agent to at least either one of the bonding surface of the distal end of the one segment conductor and the bonding surface of the distal end of the other segment conductor.