JPH09285054A - Insulating method for stator core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reliable insulating method for a stator core by preventing a crack in a corner part of the stator core in a motor. SOLUTION: A yoke part 2 of a stator core 1 has I-shaped tooth parts 3a at equal intervals and a pair of symmetrical C-shaped tooth parts 3b from base ends of the tooth parts 3a on both sides, while an inner groove 4a and an outer groove 4b are formed on inner and outer sides of the C-shaped tooth parts 3b. The stator core 1 is covered in an insulated state by insert molding with resin except for an end part of the tooth parts 3a opposing to a rotor. In this case, the stator core 1 is impregnated with heat-resistant varnish, such as polyester varnish, and dried first of all. After that a groove insulating layer 5 is formed in the grooves 4a and 4b, and an edge plate 6 is formed in a body at an edge of the stator core 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for insulating a stator core, and more particularly, to a method and a process for forming a groove insulating layer and an end plate.

[0002]

2. Description of the Related Art Conventionally, as an example of a method of insulating a stator core in an electric motor, as shown in FIG. 6, a substantially I-shaped tooth portion 3a is provided from a yoke portion 2 of a stator core 1 at equal intervals. Symmetrical substantially U-shaped tooth portions 3b are provided on both sides of every other base end of the substantially I-shaped tooth portions, and inner grooves 4a are provided inside and outside the substantially U-shaped tooth portion, respectively. The outer groove 4b is formed, and at least the tips of the tooth portions facing the rotor are removed, and the stator core is covered by insert molding with a resin to cover the stator core, as shown in FIG. The insulating layer 5 and the end plate 6 were integrally molded.

In this case, stress is generated due to thermal expansion and contraction and the like, and at the corner portion which becomes the boundary between the groove insulating layer 5 and the end plate 6,
There is a problem that stress concentration may occur and cracks may occur.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art. Insulation of a stator core is achieved by preventing cracks at the corners of the stator core of an electric motor and improving reliability. It is intended to provide a way.

[0005]

In order to achieve the above object, a plurality of tooth portions protruding from a yoke portion of a stator iron core are provided, and grooves are formed between the tooth portions to form at least a rotor and a rotor. Except for the tips of the tooth portions facing each other, in a method of insulating a stator core that is insert-molded with resin to cover the stator core, after impregnating and drying the heat resistant varnish on the stator core, a groove is formed in the groove. End plates are formed on both ends of the insulating layer and the stator core.

The thickness of the groove insulating layer and the end plate is at least 2 mm. Further, the material of the resin is a thermoplastic resin.

Further, the thermoplastic resin is PBT (polybutylene terephthalate), PPS (polyphenylene sulfide) or PET (polyethylene terephthalate).

On the other hand, the varnish is an electrically insulating varnish of solvent type or solventless type E or more, for example, polyester varnish.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION A plurality of tooth portions projecting from a yoke portion of a stator core are provided, grooves are formed between the tooth portions, and at least the tips of the tooth portions facing the rotor are excluded. , In a method of insulating a stator core by insert molding with a resin to cover the stator core, after impregnating and drying the heat resistant varnish on the stator core, the groove insulating layer in the groove and both ends of the stator core The end plate is molded into the plate.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail with reference to the accompanying drawings. Here, the same reference numerals are used for the same parts as in the related art. FIG. 1 is a plan view showing an insulated stator core according to an embodiment of the present invention. FIG. 2 is an enlarged sectional view of a main part showing a stator core subjected to a varnish treatment in a first step. Is
FIG. 3 is an enlarged sectional view of a main part corresponding to AA ′ in FIG. 2. Also,
FIG. 4 is an enlarged sectional view of a main part showing a stator core formed with an end plate and a groove insulating layer in the second step, and FIG. 5 is an enlarged sectional view of a main part corresponding to BB 'in FIG.

In this embodiment, substantially I-shaped tooth portions 3a are provided at equal intervals from the yoke portion 2 of the stator iron core 1, and the substantially I-shaped tooth portions are provided on both sides of the base end of every other tooth portion. A symmetrical substantially U-shaped tooth portion 3b is provided, and an inner groove 4a and an outer groove 4b are formed inside and outside the substantially U-shaped tooth portion 3b, respectively. The present invention is not limited to this stator core.

First, the varnish processing step is performed first, which will be described with reference to FIGS. 2 and 3.

In this step, a polyester varnish of heat-resistant varnish 7 which is an electrically insulating varnish of solvent type or solventless type E or more is provided on the stator iron core except at least the tips of the tooth portions facing the rotor. Impregnate and dry.

Next, the step of forming the groove insulating layer and the end plate is performed, which will be described with reference to FIGS. 4 and 5. Here, the thickness t of the groove insulating layer 5 and the end plate 6 is insert-molded by PBT (polybutylene terephthalate) which is a thermoplastic resin so as to be at least 2 mm, which corresponds to the electrical appliance control method in the same manner.

In this way, by molding the insulating layer by the above-mentioned two steps, even if a stress is generated due to the thermal expansion and contraction, the corner portion which becomes the boundary between the groove insulating layer and the end plate has the varnish. The treatment can absorb the stress.

Further, since the thickness of the groove insulating layer and the end plate is at least 2 mm, it corresponds to the electrical appliance control method.

Furthermore, cracks are unlikely to occur because a thermoplastic resin is used. The thermoplastic resin is PPS
(Polyphenylene sulfide) or PET (polyethylene terephthalate) may be used.

[0018]

As described above, in the present invention, a plurality of tooth portions projecting from the yoke portion of the stator core are provided, and grooves are formed between the tooth portions, respectively, and at least face the rotor. In a method of insulating a stator core, which covers the stator core by insert molding with a resin, excluding the tip of the tooth portion,
The stator core was impregnated with a heat resistant varnish and dried, and then a groove insulating layer was formed in the groove and end plates were formed at both ends of the stator core.

As a result, it is possible to provide a stator core insulation method that prevents cracks at the corners of the stator core of the electric motor and improves reliability.

[Brief description of drawings]

FIG. 1 is a plan view showing an insulated stator core according to an embodiment of the present invention.

FIG. 2 is a main part enlarged plan view showing a stator core subjected to a varnish treatment in a first step of the present invention.

FIG. 3 is an enlarged sectional view of a main part corresponding to AA ′ of FIG. 2;

FIG. 4 is an enlarged plan view of a main part showing a stator core formed with a groove insulating layer and an end plate in a second step of the present invention.

FIG. 5 is an enlarged sectional view of a main part corresponding to BB ′ in FIG. 4;

FIG. 6 is an enlarged plan view of an essential part showing an example of a conventional stator iron core subjected to an insulation treatment.

FIG. 7 is an enlarged sectional view of a main part corresponding to CC ′ in FIG. 6;

[Explanation of symbols]

 1 Stator core 2 Yoke part 3a Almost I-shaped tooth part 3b Almost U-shaped tooth part 4a Inner groove 4b Outer groove 5 Groove insulating layer 6 End plate 7 Varnish t Thickness of insulating layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Kawai 1116 Suenaga, Takatsu-ku, Kawasaki City, Fujitsu General Ltd. (72) Inventor Yuji Soma 1116 Suenaga, Takatsu-ku, Kawasaki City, Fujitsu General

Claims (6)

[Claims] 1. A resin core is provided with a plurality of tooth portions projecting from a yoke portion of a stator core, grooves are formed between the tooth portions, and at least the tips of the tooth portions facing the rotor are removed. In a method for insulating a stator core by insert molding to cover the stator core, after impregnating and drying the heat resistant varnish on the stator core, a groove insulating layer is formed in the groove and ends are formed at both ends of the stator core. A method for insulating a stator core, comprising forming a plate. 2. The method for insulating a stator core according to claim 1, wherein the groove insulating layer and the end plate have a thickness of at least 2 mm. 3. The stator core insulation method according to claim 1, wherein the resin material is a thermoplastic resin. 4. The method for insulating a stator core according to claim 3, wherein the thermoplastic resin is PBT (polybutylene terephthalate), PPS (polyphenylene sulfide) or PET (polyethylene terephthalate). 5. The varnish is solvent type or solventless type E.
The method for insulating a stator core according to claim 1, wherein the insulating varnish is at least one kind. 6. The method for insulating a stator core according to claim 5, wherein the electrically insulating varnish is a polyester varnish.