JPH09219949A - Rotating electric machine and insulation sheet for electric equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotating electric machine capable of improving the heat resistance and machine inserting property of slot insulation. SOLUTION: A slot insulation 10 consisting of an insulation sheet made by adhering PET films to both surfaces of unwoven cloth of aromatic polyimide inside a slot 9 formed in an inner peripheral portion of a stator core 6a is provided; and a self-lubricating enamel wire 11 is wound to form a random coil, thereby constituting a stator winding 6b. Then, an insulation wedge 12 made of the same insulation sheet as the slot insulation 10 is driven to the opening of slot 9, an insulation varnish made of an unsaturated polyester resin or unsaturated epoxyester resin is impregnated to the inside of the slot 9 and end portions of the winding and hardened by heating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary electric machine and an insulating sheet for electric equipment, and more particularly to a rotary electric machine such as a squirrel-cage induction motor suitable for class F (155 ° C.) insulation, and such a rotary electric machine. The present invention relates to an insulating sheet suitable for use in electric equipment.

[0002]

2. Description of the Related Art FIG. 7 shows an example of a rotating electric machine, for example, a general-purpose cage induction motor.

In FIG. 7, reference numeral 1 denotes a housing, also called a frame or a frame, which is made of cast iron, a steel plate or the like in a substantially cylindrical shape and constitutes an outer cover of an electric motor. Reference numerals 2 and 3 are end brackets, which are also called bearing brackets, which house the bearings 4 and 5, are fitted at both ends of the housing 1 by means of a spigot, and are attached by bolts or the like.
Reference numeral 6 denotes a stator, which is composed of a stator core 6a made of a laminated body of silicon steel plates, and a stator winding 6b wound around a plurality of slots provided in the inner peripheral portion of the stator core 6a. Has been done. Reference numeral 7 denotes a rotor, which is a rotor core 7a made of a laminated body of silicon steel plates, and a cage rotor winding (a conductive bar and an end ring) die-cast on the rotor core 7a. 7b and cooling vanes 7c, and is attached to the rotary shaft 8. In this figure, only the end ring portion of the car rotor winding 7b is shown. The rotary shaft 8 is rotatably held by the bearings 4 and 5 of the end brackets 2 and 3, whereby the rotor 7 is configured to rotate at a position facing the stator 6.

Further, as shown in FIG. 1, the stator winding 6 is
b is obtained by randomly winding a synthetic resin enameled wire 11 in a slot 9 provided in the inner peripheral portion of the stator iron core 6a through a slot insulator 10 having a substantially U-shaped cross section by, for example, a winding machine. The arc-shaped insulating wedge 12 is driven into the opening of the slot 9 to form the stator winding 6b.
In the slot and insulate the stator core 6a, and further, the insulating varnish is impregnated into the inside of the slot 9 and the winding end portion protruding outside the slot 9 and heat-cured to integrally fix them. ing.

The slot insulator 10 and the insulating wedge 12 are, for example, aromatic polyamide (Dupont).
Company: Nomex: registered trademark) sheet alone or polyethylene terephthalate (hereinafter abbreviated as PET) sheet alone is used, and the synthetic resin enamel wire 11 is, for example, an ester imide wire or a polyester amide imide wire. As the insulating varnish, a solvent type insulating varnish containing an organic solvent such as styrene, toluene, xylene, or a solventless type insulating varnish is used.

On the other hand, JP-A-59-4002, JP-A-59-4003 and JP-A-59-63944.
Japanese Patent Laid-Open Publication No. 2005-163242 discloses an electric winding of class F insulation for a general-purpose electric motor in which an insulating sheet and a water-soluble insulating varnish are combined.

In JP-A-59-4002, a laminate of a polyester sheet and an ethylene tetrafluoride sheet is used as the insulating sheet. In JP-A-59-4003, a polyester sheet is used. A laminated polypropylene sheet is used, and in JP-A-59-63944, a polyester sheet coated with an aramid resin and baked is used.

[0008]

However, since the above-mentioned conventional techniques all use the water-soluble insulating varnish,
The heat-curing requires a long time, and there is a risk that water remains after the heat-curing, which is a particular problem in a sealed electric motor in which residual water is difficult to escape.

In order to reduce the size and weight of the rotating electric machine,
It is necessary to improve the space factor of the winding in the slot and to reduce the radius of curvature at the end of the winding. Along with this, the enamel wire 11 and the slot insulator 10 of the enamel wire 11 are required.
If the slip on the enamel wire is not good, there is a problem that the enamel wire is easily scratched by being rubbed by the slot portion at the time of winding, and it is difficult to insert the enamel wire, resulting in poor workability.

Further, when the above-mentioned aromatic polyamide sheet alone is used as the slot insulator 10 and the insulating wedge 12, there is no problem in heat resistance, but since the rigidity is relatively low, the machine insertability into the slot is high. There is a problem that the cost is high and the material cost is high. Further, when the PET sheet alone is used, the mechanical insertability into the slot is good, but the heat resistance is limited to the type B insulation.

Accordingly, a first object of the present invention is to provide a rotating electric machine capable of improving the heat resistance and mechanical insertability of a slot insulator.

A second object of the present invention is to provide a rotating electric machine capable of improving heat resistance and mechanical insertability of a slot insulator and reducing damage to a coating of an electric wire constituting a stator winding. It is in.

A third object of the present invention is to provide a rotating electric machine that can improve the heat resistance and mechanical insertability of a slot insulator and the heat resistance and crack resistance of an insulating varnish. .

Further, a fourth object is to improve the heat resistance of the slot insulator and the machine insertability, improve the heat dissipation from the housing, and reduce the size and weight of the machine. To provide.

Still another object of the present invention is to provide an insulating sheet which is excellent in heat resistance and rigidity and is used for electric equipment such as a rotary electric machine.

[0016]

In order to solve the above problems, the present invention uses, as a slot insulating material, an insulating sheet obtained by laminating a PET film on both sides of an aromatic polyamide nonwoven fabric, and more preferably, the above. The slot insulator is characterized in that the total thickness thereof is 0.05 to 0.35 mm, and the thickness of the aromatic polyamide nonwoven fabric is 33 to 50% of the total thickness of the sheet, Further, the stator winding, characterized in that it is composed of a self-lubricating enamel wire, further, as the insulating varnish,
An unsaturated polyester resin or an unsaturated epoxy ester resin is used, and more preferably, a cured product of the above insulating varnish has a glass transition temperature of 120 ° C. or less and a linear expansion coefficient of 7.0 × 10 ⁵ / ° C. or less. In addition, the initial elastic modulus at room temperature is 100 to 350 kg / mm ^2, and the housing is made of aluminum alloy die casting. A PET film is laminated on both sides of the aromatic polyamide nonwoven fabric.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS. 1, 2 and 7.

The structure of a rotary electric machine to which the present invention is applied, for example, a general-purpose squirrel-cage induction motor is almost the same as that of the conventional general-purpose squirrel-cage induction motor shown in FIGS. 7 and 2.
The following points are different.

That is, in this embodiment, as the insulating sheet 13 used for the slot insulator 10 and the insulating wedge 12, as shown in FIG. 2, a PET film 15 is adhered to both sides of an aromatic polyamide nonwoven fabric 14 with an adhesive. It is used by pasting together.

The adhesive used here may be either solvent-free or solvent-based, but a curable solvent-based adhesive is preferable in view of heat resistance of the adhesive and workability of laminating the adhesive. As an example of the polyurethane-based adhesive, a commercially available polyurethane-based adhesive may be used. Preferred is a polyurethane-based adhesive prepared by preparing a prepolymer of an isocyanate obtained by reacting the above with the prepolymer and polypropylene glycol, polyester, polyol or the like. The prepolymer and polypropylene glycol, polyester, polyol and the like are uniformly mixed in an organic solvent such as ethyl acetate and butyl acetate to form an adhesive solution. In addition, an inorganic or organic additive such as a flame retardant may be added to the adhesive to such an extent that the adhesiveness is not impaired.

The insulating sheet 13 having such a configuration has good compatibility with an insulating varnish described later, and the characteristics are not deteriorated by heat deterioration. This is because initially, the insulating sheet 13 has good chemical resistance to styrene and the like in the insulating varnish, and
PET film 1 on both sides of aromatic polyamide nonwoven fabric 14
5 improves the rigidity of the insulating sheet 13 as a whole, the mechanical insertability into the slot 9 is improved, and the aromatic polyamide nonwoven fabric 14 itself has heat resistance.
The core material of No. 5 improves the heat resistance of the insulating sheet 13 as a whole, and the insulating sheet 13 as a whole satisfies the heat resistance of the F-type insulation.

As the enamel wire 11, for example, a self-lubricating enamel wire in which a lubricant is applied to the surface or a lubricant is contained in the coating so that the lubricant oozes out on the surface is used. By using such a self-lubricating enameled wire, slippage between the enameled wires 11 and the slot insulating sheet 13 is improved, damage to the coating of the enameled wire 11 is reduced, and winding workability is also improved. The self-lubricating enameled wire is preferably one that is excellent in heat resistance, chemical resistance, surface lubricity and wear resistance, and is suitable for F-type insulation, which is excellent in machine insertability into the slot 9.

Further, as an insulating varnish for impregnating the winding end portion protruding into the slot 9 and to the outside of the slot 9, an unsaturated epoxy ester resin or an unsaturated resin excellent in high adhesive strength, crack resistance, chemical resistance and the like is used. Polyester resin is used. Of the mechanical forces acting on the stator winding 6b, considering the stress during operation, which is particularly important, the stress due to the heat cycle at the time of starting and stopping (due to the difference in thermal expansion between the conductor and the insulating layer) and the electromagnetic force. Force and vibration force due to the rotation of the rotor. The wear and peeling of the insulating layer of the stator winding 6b due to these stresses can be sufficiently prevented by using the above-mentioned insulating varnish. You will be satisfied. A cured product of an insulating varnish obtained by impregnating the stator winding 6b or the like with such an insulating varnish and having a glass transition temperature of 120 ° C. or less and a linear expansion coefficient of 7.0 × 10 ⁵ / ° C. The thermal stress generated during the heat cycle of the stator winding 6b treated with the insulating varnish is further reduced by selecting the following one having an initial elastic modulus at room temperature of 100 to 350 kg / mm ^2. The heat resistance of the F-type insulation can be achieved.

Further, the housing 1 is made of cast iron or steel plate or aluminum alloy die-cast as in the prior art. When the aluminum alloy die-cast housing is used, the heat dissipation (heat conductivity) is better than when the housing is made of cast iron or steel plate. Insulation can be used and miniaturization can be achieved. Also, if it is made of die-cast, it can accurately form thin and thick parts as designed, so it does not require much machining, etc., and the manufacturing process can be shortened. Since the specific gravity is smaller than that of cast iron or the like, it is possible to reduce the weight.

Further, the insulating sheet 13 shown in FIG.
The present invention is not limited to the slot insulator 10 and the insulating wedge 12 described above, but can be used for insulating other electric devices, and when widely used for electric devices, the PET films 15 on both sides of the aromatic polyamide nonwoven fabric 14 are used. Increases the rigidity of the insulating sheet as a whole, and the aromatic polyamide nonwoven fabric 14 itself has heat resistance and serves as the core material of the PET film 15 to increase the heat resistance of the insulating sheet as a whole. It has excellent heat resistance.

[0026]

【Example】

[Example 1] An insulating sheet 13 (manufactured by Shinko Kagaku: TNT252: trade name) in which a PET film 15 having a thickness of 50 µm is adhered to both sides of an aromatic polyamide nonwoven fabric 14 having a thickness of 125 µm is molded into a substantially U-shape to form a slot insulator. 10 is provided in the slot 9 of the stator core 6a.

Inside the slot insulator 10, a winding 6b made of a self-lubricating amide imide overcoat ester imide wire (Hitachi Cable: 1AI-EIW-E: trade name) 11 is inserted, and the insulation is further provided. After the insulating wedge 12 formed by forming the sheet 13 into a substantially arcuate cross section is driven and the inside of the slot 9 and the winding end portion are impregnated with unsaturated epoxy ester varnish (Nitto Denko: NV-5502: trade name) Then, it was heat-cured at 100 to 160 ° C. and integrally fixed to the stator iron core 6a to produce the stator 6. Further, the rotor core 7a is integrally formed with the squirrel cage rotor winding 7b and the cooling vanes 7c by the aluminum die casting method to manufacture the rotor 7.

Then, the stator 6 is inserted into a heat-expanded casting housing having an outer diameter of 250 mm, and the rotor 7 is assembled by using the end brackets 2, 3, and the bearings 4, 5. Completed a 7 kW 4-pole cage induction motor.

The insulating sheet 13 (having a film thickness of 125 μm)
m of aromatic polyamide non-woven fabric 14 on both sides of P of 50 μm
An insulating varnish treatment was performed under the same conditions as those for producing the squirrel-cage induction motor described above to prepare a test piece for a tensile test.

As a typical example of the thermal deterioration characteristics of the tensile strength of the insulating sheet 13, the characteristic at 210 ° C. is shown as the characteristic A in FIG. 4, and the initial tensile strength at each thermal deterioration temperature of 165 to 210 ° C. is 50% of the initial tensile strength. FIG. 6 shows the Arrhenius plot with the life until the time until it becomes the same as the characteristic A.

As shown by the characteristic A in FIG. 4, the strength reduction is remarkably improved as compared with Comparative Example 1 described later, and the heat resistance temperature corresponding to 20,000 hours in FIG. It was confirmed to have.

Note that the tensile test of the insulating sheet 13 was performed with a width 1
A 5 mm x 200 mm long test piece was manufactured by Shimadzu DS
Using S-5000 type autograph, distance between check 1
It was performed at 00 mm and a pulling speed of 200 mm / min. Also,
In the heat deterioration test, the test piece was suspended in a hot-air circulation type constant temperature bath at temperatures of 210 ° C., 180 ° C., and 165 ° C., taken out after a lapse of a predetermined time, and the tensile test was performed. In addition, the tensile test showed the average value of five test pieces at 25 degreeC.

Example 2 A 75 μm PET film 1 is formed on both sides of an aromatic polyamide nonwoven fabric 14 having a film thickness of 100 μm.
Insulation sheet 13 with 5 attached (Shinko Kagaku: TNT3
43: Trade name) is used, and the characteristic at 210 ° C. is shown in the characteristic B of FIG. 4 as a representative example of the thermal deterioration characteristic of the tensile strength of the insulating sheet manufactured in the same manner as in the above-mentioned Example 1.
Further, characteristic A of FIG. 6 shows an Arrhenius plot when the life is defined as the time taken to reach 50% of the initial tensile strength at each heat deterioration temperature of 165 to 210 ° C.

As can be seen from the characteristic B in FIG. 4, the decrease in strength is greatly improved as compared with Comparative Example 1 described later, and the heat resistance temperature corresponding to 20,000 hours in FIG. It was confirmed to have heat resistance of.

Example 3 A PET film 15 having a thickness of 75 μm is formed on both sides of an aromatic polyamide nonwoven fabric 14 having a thickness of 75 μm.
Insulation sheet 13 with affixed to it (made by Shinko Kagaku: TNT33
3: as a representative example of thermal deterioration characteristics of tensile strength measured using a test piece manufactured in the same manner as in Example 1 except that (trade name) is used.
Shown in Further, characteristic A of FIG. 6 shows an Arrhenius plot when the life is defined as the time until the initial tensile strength reaches 50% at each heat deterioration temperature of 165 to 210 ° C.

As can be seen from the characteristic C of FIG. 4, the decrease in strength is improved as compared with Comparative Example 1 described later, and the heat resistance temperature corresponding to 20,000 hours in FIG. 6 is 159 ° C. It was confirmed that the product has sex.

Example 4 A 25 μm PET film 1 is formed on both sides of an aromatic polyamide nonwoven fabric 14 having a film thickness of 175 μm.
Insulation sheet 13 with 5 attached (Shinko Kagaku: TNT1)
71: product name) was used, and the stator 6 was manufactured in the same manner as in Example 1 above. Further, unsaturated epoxy ester varnish (Nitto Denko: NV-5502: trade name) is impregnated,
The characteristic at 210 ° C. is shown in the characteristic D of FIG. 4 as a representative example of the thermal deterioration characteristic of the tensile strength of the heat-cured insulating sheet.

As shown by the characteristic D in FIG. 4, the strength reduction was remarkably improved as compared with Comparative Example 1 described later. Also, 210
In the 55-day heat deterioration due to the heat deterioration temperature of ° C, the deterioration was saturated and did not proceed further, and the tensile strength of the insulating sheet did not decrease to 50% of the initial value. Further, the tensile strength of the insulating sheet was not significantly reduced even at other heating deterioration temperatures.

[Embodiment 5] A PET film 1 of 100 μm is formed on both sides of an aromatic polyamide nonwoven fabric 14 having a film thickness of 50 μm.
Insulation sheet 13 with 5 attached (Shinko Kagaku: TNT4
24: Trade name) is used, and the characteristic at 210 ° C. is shown in the characteristic E of FIG. 4 as a representative example of the thermal deterioration characteristic of the tensile strength of the insulating sheet manufactured in the same manner as in the above-mentioned Example 1.
In addition, an Arrhenius plot when the time taken to reach 50% of the initial tensile strength at each heat deterioration temperature of 165 to 210 ° C. is defined as the life is shown as a characteristic E in FIG.

As can be seen from the characteristic E of FIG. 4, the decrease in strength is improved as compared with Comparative Example 1 described later, and the heat resistant temperature corresponding to 20,000 hours in FIG. It was confirmed that the product has sex.

[Comparative Example 1] FIG. 3 shows a cross-sectional structural view of the insulating sheet 16 used in this comparative example.

In the same manner as in Example 1 except that the insulating sheet 16 (manufactured by Shinko Kagaku: NTN252: trade name) in which the aromatic polyamide nonwoven fabric 17 having a thickness of 50 μm is bonded to both sides of the PET film 18 having a thickness of 125 μm is used. As a typical example of the thermal deterioration characteristics of tensile strength of the produced insulating sheet, 210
The characteristic at ° C is shown in the characteristic F of FIG. Also, 165-
5 of initial tensile strength at each heat deterioration temperature of 210 ℃
The characteristic A of FIG. 6 shows an Arrhenius plot when the life is defined as the time until it reaches 0%.

As can be seen from the characteristic F of FIG. 5, the strength is greatly reduced, and the heat resistant temperature corresponding to 20,000 hours in FIG. 6 is 139.
It was confirmed that the temperature did not reach the temperature of ℃ and the heat resistance of the F-type insulation was not provided.

[Comparative Example 2] Thermal degradation of tensile strength of an insulating varnish-treated insulating sheet produced in the same manner as in Example 1 except that an insulating sheet made of a PET film alone having a thickness of 250 μm was used as a slot insulator. As a typical example of the characteristic, the characteristic at 210 ° C. is shown in characteristic G of FIG. Further, characteristic A of FIG. 6 shows an Arrhenius plot when the time taken to reach 50% of the initial tensile strength at each heat deterioration temperature of 165 to 210 ° C. is the life.

As can be seen from the characteristic G in FIG. 5, the tensile strength was greatly reduced, and the heat resistance temperature corresponding to 20,000 hours in FIG. 6 was 136 ° C., and it was confirmed that the heat resistance of the F-type insulation was not obtained. .

[Comparative Example 3] The tensile strength of the insulating varnish-treated insulating sheet produced in the same manner as in Example 1 was changed except that an insulating sheet made of an aromatic polyamide nonwoven fabric having a film thickness of 250 μm was used as the slot insulating material. The characteristic at 210 ° C. is shown as a characteristic H in FIG. 5 as a representative example of the thermal deterioration characteristic. As can be seen from the characteristic H of FIG. 5, the tensile strength of the insulating sheet was hardly reduced even when it was deteriorated by heating at 210 ° C. for 55 days. Further, the tensile strength of the insulating sheet was not significantly reduced even at other heating deterioration temperatures.

[Embodiment 6] An unsaturated polyester varnish (manufactured by Hitachi Chemical Co., Ltd.) is used as an insulating varnish that is impregnated into the inside of the slot 9 of the stator core 6a of FIG.
WP-435H: trade name), and the thermal deterioration characteristics of the tensile strength of the insulating sheet produced in the same manner as in Example 1 were measured.

The tensile strength of this example was smaller than that of Comparative Example 1 at each deterioration temperature, and the time until the tensile strength at each heat deterioration temperature reached 50% of the initial value was the life, and was determined by an Arrhenius plot. The heat resistant temperature of 20,000 hours was 158 ° C.

Example 7 In order to measure the crack resistance of a stator winding conductor treated with an insulating varnish due to thermal stress generated during the heat cycle, a self-lubricating amideimide overcoat esterimide wire (Hitachi Cable) Made: 1AI
-EIW-E: A bifilar coil is manufactured with a product name), and this is impregnated with an unsaturated epoxy ester varnish (Nitto Denko: NV-5502: a product name), and 150 ° C.
Cured for 2 hours.

This bi-farer coil was subjected to a heat cycle test of 155 ° C./2 hours ⇔ -40 ° C./2 hours as one cycle for 5 cycles. As a result, no cracks were found in any of the bifilar coils.

Separately from this, a resin plate was prepared from NV-5502 under the same curing conditions as above. The resin plate was machined to prepare a test piece A having an 8 mm square and a thickness of 15 mm, and a test piece B having a width of 4 mm, a thickness of 1 mm and a length of 35 mm. Using a thermophysical tester TMA-3000 manufactured by Vacuum Riko Co., Ltd., the glass transition temperature (Tg) and the linear expansion coefficient (α) of Tg or less of the test piece A were used, and a rheological viscoelasticity measuring device DVE-V4 was used. Then, the tensile elastic modulus of the test piece B at room temperature was obtained.

The Tg of the resin cured product of this example is 115 ° C.,
α was 6.9 × 10 ⁵ / ° C., and the tensile elastic modulus at room temperature was 345 kg / mm ² .

Example 8 An unsaturated polyester varnish (WP-435H manufactured by Hitachi Chemical Co., Ltd.) was used as an insulating varnish for dipping and impregnating a bifilar coil.
A bifilar coil was prepared in the same manner as in Example 7 except that the composition was cured at 3 ° C. for 3 hours, and subjected to a heat cycle test, Tg,
α and the tensile modulus at room temperature were measured. The results of the heat cycle test were good, with Tg of 66 ° C and α of 5.8.
× 10 ~ ⁵ / ℃, room temperature tensile elastic modulus is 105kg / mm
^{Was 2} .

[Comparative Example 4] An acid-cured epoxy varnish (KE-571: trade name, manufactured by Hitachi Chemical Co., Ltd.) was used as an insulating varnish for dipping and impregnating a bifilar coil.
A bifilar coil was produced in the same manner as in Example 7 except that curing was performed at 150 ° C. for 1 hour, and the heat cycle test, T
The tensile modulus at g, α and room temperature was measured.

As a result, in the heat cycle test, cracks occurred in two of the five bifilar coils at the fifth cycle. The Tg of the resin cured product of this comparative example is 1
At 25 ° C., α was 7.2 × 10 ⁵ / ° C., and the tensile elastic modulus at room temperature was 370 kg / mm ² .

[Comparative Example 5] The same as Example 1 except that a PET film alone was used as the insulating sheet constituting the slot insulator and an ester imide wire was used as the enamel wire constituting the stator winding. A 3.7 kw 4-pole squirrel-cage induction motor in which the housing holding the stator is made of cast iron having an outer diameter of 223 mm was manufactured, and its weight and volume were measured. This was compared with Example 9 described below.

[Embodiment 9] A 3.7-kW four-pole squirrel-cage induction motor similar to that of Embodiment 1 is manufactured except that the housing holding the stator is made of aluminum alloy die cast with an outer diameter of 223 mm. The volume was measured and compared with Comparative Example 5.

When the weight and volume of Comparative Example 5 were 100, respectively, the weight and volume of this example were 70 and 89, respectively, which were significantly reduced.

Aluminum alloy, which is the material of the housing, has a high thermal conductivity and a low density as compared with cast iron.
Further, in the aluminum alloy die casting method, the molten aluminum alloy is injected into the mold at high pressure, so that voids in the product can be eliminated, and a product with sufficient strength even in the thin portion can be obtained. For this reason, the aluminum alloy die-cast housing enables high-efficiency product design with CAE (Computer Aided Engineering) maintaining strength while eliminating extra parts, and is smaller and lighter than cast iron housings. I was able to.

For the above reasons, the squirrel-cage induction motor of this embodiment using the aluminum alloy die-cast housing can be made smaller and lighter than the squirrel-cage induction motor of Comparative Example 5, as described above.

As a summary of each of the above-mentioned Examples, Examples 1, 2, and 3 are Comparative Example 1 as shown in the characteristic diagram of FIG.
Compared with, the characteristics of the insulating sheet were significantly improved.
In addition, since Example 4 is an insulating sheet in which the ratio of the thickness of the aromatic polyamide nonwoven fabric is large, the characteristics of the insulating sheet are significantly improved as compared with Comparative Example 1, but the mechanical properties of the slot insulating material inside the slot are improved. The insertability was slightly poor.

At heat resistant temperatures equivalent to 20,000 hours in Examples 1 to 4, an improvement of about 17 ° C. or more was observed as compared with Comparative Example 1.
It satisfied the seed insulation.

In Examples 1 to 4, the heat resistance can be improved for the following reasons by laminating the PET films on both sides of the aromatic polyamide nonwoven fabric.

The insulating sheets of Examples 1 to 4 use an aromatic polyamide non-woven fabric as the core material and have PET on both sides.
The films are stuck together. Since the surface layer has the PET film, only the surface layer of the PET film is affected by the organic solvent such as styrene or water contained in the insulating varnish, and the aromatic polyamide nonwoven fabric as the core material is not easily affected by these. Further, by using a heat-resistant aromatic polyamide nonwoven fabric as the core material, the heat resistance of the PET film can be significantly improved and the heat resistance of the insulating sheet as a whole can be improved. On the contrary, in the insulating sheet of Comparative Example 1, a PET film was used as the core material, and the aromatic polyamide nonwoven fabric was attached to both surfaces thereof. Since the aromatic polyamide non-woven fabric of the surface layer easily penetrates the insulating varnish and water, the PET film of the core material is also easily affected by the organic solvent such as styrene contained in the insulating varnish or water, and the insulating sheet as a whole is aromatic. It greatly reduces the heat resistance of group polyamide nonwoven fabrics. As described above, in Comparative Example 1, the heat resistance of the PET film having a heat resistant aromatic polyamide nonwoven fabric as a constituent unit is as low as that of a PET film having a low heat resistance, and the heat resistance is lowered, which is a problem in practical use. Since Comparative Example 2 uses the PET film alone, it has insufficient heat resistance as shown by the characteristic G in FIG. Comparative Example 3 was very excellent in that the tensile strength of the insulating sheet did not decrease as shown by the characteristic H in the characteristic diagram of FIG. 5, but the mechanical insertability of the slot insulator into the slot was poor. This is because the elastic modulus of the aromatic polyamide nonwoven fabric is PET
This is probably because the rigidity is lower than the bending when inserting the slot insulator into the slot because it is lower than that of a sheet or the like. Although it has been attempted to increase the thickness of an aromatic polyamide nonwoven fabric to increase its rigidity, this is not done so much because the cost becomes high and some anxiety about electrical characteristics such as dielectric strength remains.

Regarding the thermal stress generated in the winding end portion and the like, as is clear from the results of the heat cycle tests of Examples 7 and 8, the cured product of the impregnated insulating varnish was Tg.
Is 120 ° C. or less, the linear expansion coefficient α is 7.0 × 10 ⁵ / ° C. or less, and the tensile elastic modulus at room temperature is 100 to 350 kg / m 2.
The thermal stress can be reduced by using an insulating varnish having a m ^{2 value} .

The machine insertability of the stator core into the slot was equal to or higher than that of the case where the PET film alone was used in all the slot insulators using the insulating sheet of this example.

Further, according to the ninth embodiment, a cage type induction motor in which a housing made of an aluminum alloy die casting and the F type insulating material of the present embodiment are combined, and a cage in which a cast housing and the F type insulating material of the present embodiment are combined are combined. Comparing the volume and weight of the induction motor, the cage induction motor using the aluminum alloy die-cast housing has a volume ratio of about 1 in comparison with the cage induction motor using the casting housing.
It is possible to reduce it by 0%, or about 30% by weight.

[0068]

As described above, according to the present invention, PE is formed on both sides of an aromatic polyamide nonwoven fabric as a slot insulator.
Since the insulating sheet made by laminating T film is used, the heat resistance of the slot insulator is improved, and moreover, PET
Mechanical insertability into the slot that is almost the same as when using a single film is obtained.

Further, since the stator winding is composed of the self-lubricating enamel wire, slipping between the enamel wires and the slot insulator is improved, damage to the coating of the enamel wire is reduced, and winding workability is improved. Can be improved.

Furthermore, since an unsaturated polyester resin or an unsaturated epoxy ester resin is used as the insulating varnish, the insulating varnish has good compatibility with the above-mentioned slot insulator and enamel wire, and its heat resistance and crack resistance can be improved. it can.

Further, since the housing is made of aluminum alloy die-cast, the heat dissipation is good, and it is possible to handle with compact insulation, so that the rotating electric machine can be downsized and each part of the housing can be formed accurately. Therefore, the machining process can be shortened without much machining, and the rotating electric machine can be made lighter than that of cast iron or the like.

Further, in the insulating sheet for electric equipment constituted by laminating the PET films on both sides of the aromatic polyamide nonwoven fabric, the PET films on both sides of the aromatic polyamide nonwoven fabric increase the rigidity of the entire insulating sheet, and Since the polyamide nonwoven fabric itself has heat resistance and becomes the core material of the PET film to increase the heat resistance of the insulating sheet as a whole,
The insulating sheet as a whole has excellent rigidity and heat resistance.

[Brief description of drawings]

FIG. 1 is a sectional view showing a stator inner peripheral slot portion of a squirrel cage induction motor.

FIG. 2 is a cross-sectional view showing an insulating sheet used in the present invention.

FIG. 3 is a cross-sectional view showing an insulating sheet of Comparative Example 1.

FIG. 4 is a thermal deterioration characteristic diagram of tensile strength of an insulating sheet.

FIG. 5 is a thermal deterioration characteristic diagram of tensile strength of an insulating sheet.

FIG. 6 is a characteristic diagram in which the life characteristics of the insulating sheet at each deterioration temperature are Arrhenius plotted.

FIG. 7 is a front view showing the upper half of the squirrel cage induction motor in a vertical section.

[Explanation of symbols]

 1 Flange 6a Stator core 6b Stator winding 9 Slot 10 Slot Insulator 11 Enamel wire 12 Insulating wedge 13 Insulating sheet 14 Aromatic polyamide nonwoven fabric 15 PET film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuichi Ohara 7-1-1, Omika-cho, Hitachi-shi, Ibaraki Hitachi Ltd. Hitachi Research Laboratory

Claims (7)

[Claims] 1. A stator, a housing to which the stator is fixed, and a rotor rotatably held in the housing via bearings, the stator including an iron core having a plurality of slots. , A rotary electric machine consisting of a winding wire housed in a slot of the iron core through a slot insulator, and in the rotating electric machine in which the slot insulator and the winding wire are impregnated with an insulating varnish and heat-cured, as the slot insulator, A rotating electrical machine comprising an insulating sheet obtained by laminating a polyethylene terephthalate film on both sides of an aromatic polyamide nonwoven fabric. 2. The insulating sheet according to claim 1, wherein:
A rotary electric machine, wherein the total thickness thereof is 0.05 to 0.35 mm, and the thickness of the aromatic polyamide nonwoven fabric is 33 to 50% of the total thickness of the insulating sheet. 3. The rotating electric machine according to claim 1, wherein the winding wire of the stator is formed of a self-lubricating enameled wire. 4. The insulating varnish according to claim 1,
An electric rotating machine characterized by being an unsaturated polyester resin or an unsaturated epoxy ester resin. 5. The cured product of the insulating varnish according to claim 4, which has a glass transition temperature of 120 ° C. or less, a linear expansion coefficient of 7.0 × 10 ⁵ / ° C. or less, and an initial elastic modulus at room temperature. Is 100 to 350 kg / mm ² . 6. The rotating electric machine according to claim 1, wherein the housing is made of aluminum alloy die casting. 7. An insulating sheet for electrical equipment, comprising a polyethylene terephthalate film laminated on both sides of an aromatic polyamide nonwoven fabric.