CROSS REFERENCE TO RELATED APPLICATION

The disclosure of Japanese Patent Application No. 2017-222315 filed on Nov. 17, 2017 including the specification, claims, drawings, and abstract is incorporated herein by reference in its entirety.

TECHNICAL FIELD

This disclosure relates to a method for manufacturing a stator whose coil end is covered with resin, and to a stator.

BACKGROUND

Patent Document 1 describes that the connection portion of the coils in a coil end is impregnated with resin and the resin is thereafter cured, whereby the connection portion in the coil end is buried in the resin.

CITATION LIST

Patent Literature

Patent Document 1: JP 2000-209802A

SUMMARY

In impregnating a coil end with resin, the resin may fail to permeate well into the upper surface side (a core side) of the coil. This may result in insufficient insulation. That is, in the case where coils are disposed at relatively density, a space may be left unfilled with resin between coils, even well below the surface of the liquid resin.

A method for manufacturing a stator according to this disclosure includes: a first resin layer forming step of forming a first thermoset resin layer by impregnating the tip end side of a coil end with first thermoset resin, the coil end protruding from the core of the stator, the first thermoset resin having liquidity; a second resin layer forming step of forming a second thermoset resin layer on the first thermoset resin layer by dropping second thermoset resin from the core side of the coil end toward the tip end side; and a curing step of curing the first thermoset resin and the second thermoset resin.

The second thermoset resin may have viscosity lower than that of the first thermoset resin.

The curing step may include a first curing step and a second curing step, the first curing step may be executed after the first resin layer forming step to cure the first thermoset resin, and the second curing step may be executed after the second resin layer forming step to cure the second thermoset resin.

In the first resin layer forming step, the first thermoset resin may be liquid and pooled inside a die, and the tip end side of the coil end may be plunged into the first thermoset resin, which is liquid, and kept plunged until the level of the liquid surface of the first thermoset resin inside the die rises along the circumferential wall of the die and lowers in the middle portion of the first thermoset resin.

The coil end including a plurality of coil conducting wires aligned in the circumferential direction of the stator may protrude from the core of the stator.

A stator according to this disclosure includes a first resin layer covering the tip end portion of a coil end protruding from the core of the stator; and a second resin layer laminated on the core side of the first resin layer so as to cover the surface of the first resin layer on the core side.

The inside edge of the first resin layer in the diameter direction of the stator and the outside edge of the first resin may both extend toward the second resin layer to thereby form banks.

The first resin layer and the second resin layer may wholly cover the tip end side of the coil end including a plurality of coil conducting wires protruding from the core.

According to this disclosure, two kinds of resins are supplied from respectively different directions, so that the resin can permeate well.

