JPH05308758A - Method of impregnating electric apparatus with varnish - Google Patents

Abstract

PURPOSE:To prevent a surplus insulating layer from being formed along the inside periphery of a winding, in a method of impregnating the winding with varnish, using a bag. CONSTITUTION:An elastic balloon-shaped inside-diameter barrier member 20 is arranged along the inside periphery of a stator 11, and this stator 11 is accommodated in an air-tight bag 21 accommodating varnish 22. This one is accommodated in a sealed tank, and the inside of the tank containing the bag 21 is decompressed. Hereby, the inside-diameter barrier member 20 expands, and sticks to the inside periphery of the stator 112 without wrinkles. The bag 21 comes to stick close to the outside periphery of the stator 11 by returning the inside of the tank to atmospheric pressure after sealing the mouth 21a of the bag 21 with a heat sealer, it is impregnated with varnish 22 being pushed in as far as the narrow space between the fellow element wires of the winding 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for impregnating varnish of electric equipment, which is an improved method of varnishing a winding body such as a stator of a rotating electric machine.

[0002]

2. Description of the Related Art In an electric device such as a rotary electric machine, a stator having a winding wound around an iron core is impregnated with a varnish to improve the insulation, heat resistance and strength of the stator. Is being done.

As a method of impregnating varnish of this type, conventionally, a dipping method in which a stator is dipped in a varnish made of a thermosetting resin and then the stator is housed in a heating furnace to heat-harden the varnish, A drop impregnation method in which a varnish is dropped onto a stator to impregnate it has been used.

However, these impregnation methods have drawbacks that the varnish is difficult to be impregnated into a narrow portion such as between the wires of the winding wire, and the varnish once impregnated may flow out.

[0005]

Therefore, the applicant of the present invention is
As a varnish impregnation method instead of the conventional dipping method or drop impregnation method, a so-called vacuum pack in which the stator is covered with an airtight bag and the varnish in the bag is impregnated into the stator while the bag is depressurized. He has developed a law and applied for it first (Japanese Patent Application No. 2-231051).

As shown in FIG. 9, in this method, first, a stator 3 formed by winding a winding 2 around a stator core 1 is housed in an airtight bag 4. At this time, the bag 4 is shown in FIG.
As shown in principle, the lower part of the lower part is folded back inward to cover the inner and outer circumferences of the stator 3.
In addition, a required amount of varnish 5 is stored in the bag 4.

After that, the mouth 4a of the bag 4 is connected to a vacuum pump to reduce the pressure inside the bag 4, thereby bringing the bag 4 into close contact with the inner and outer peripheral surfaces of the stator 3 and fixing the varnish 5 inside. The child 3 is impregnated, and then the stator 3 is covered with the bag 4 and heated in a heating furnace to cure the varnish 5.

According to such a method, the varnish 5 can be impregnated in a depressurized state, so that the varnish 5 can be impregnated into a narrow space such as between the wires of the winding wire 2.
Since the varnish is impregnated while the stator 3 is covered with the airtight bag 4, it is possible to prevent the varnish 5 from flowing out, and it is possible to obtain an advantage that the equipment is relatively simple. You can do it.

However, even with such a vacuum packing method, there is still room for improvement in the following points.
That is, the bag 4 is made of, for example, a flexible plastic film, and has a diameter slightly larger than that of the stator 3 and a sufficiently large length. The folded back portion has a diameter sufficiently larger than the inner diameter of the stator 3 and covers the inner peripheral portion of the stator 3.

Therefore, when the inside pressure is reduced, the bag 4 comes into close contact with the inner peripheral portion of the stator 3 in a state where wrinkles are formed, and the varnish 5 also enters the inside of the wrinkles. .. As a result, an extra insulating layer corresponding to the wrinkles is formed on the inner peripheral surface of the stator 3, and it is necessary to remove the extra insulating layer after that.

Therefore, an object of the present invention is a so-called vacuum packing method in which a varnish is impregnated in a state in which an annular winding body is covered with an airtight bag, and an extra insulating layer is formed on an inner peripheral portion of the winding body. It is to provide a method for impregnating a varnish of an electric device, which can prevent the formation of varnish.

[0012]

According to the method for impregnating varnish of an electric device of the present invention, an annular winding body composed of an iron core and a winding provided on the iron core is formed from a stretchable material at its inner peripheral portion. The balloon-shaped inner diameter barrier member is placed in an airtight bag, the inside of the bag is depressurized, and the winding body is impregnated with the varnish housed in the bag under this depressurized state. It has a feature in the place.

Further, in this case, the winding body housed in the bag is housed in a closed tank, the inside of the tank is decompressed, and the mouth portion of the bag is sealed in that state. It is more effective if the winding body is impregnated with the varnish contained in the bag by returning to atmospheric pressure.

[0014]

According to the method for impregnating varnish of electric equipment of the present invention,
Since the winding body contained in the airtight bag is impregnated with the varnish under reduced pressure, it is possible to impregnate the varnish into the narrow spaces between the wire strands of the winding or between the winding and the iron core. it can. In addition, since the outer peripheral portion of the winding body is covered with the bag, the impregnated varnish can be prevented from flowing out.

A balloon-shaped inner diameter barrier member made of a stretchable material is arranged on the inner peripheral portion of the winding body. When the inside of the bag is depressurized, the inner diameter barrier member is When the negative pressure is applied, it expands and comes into close contact with the inner peripheral surface of the winding body. In this case, since the inner diameter barrier member comes into close contact with itself without wrinkling due to its elasticity, it is possible to prevent an extra insulating layer from being formed on the inner peripheral portion of the winding body.

Further, if the winding body covered with the bag is housed in a closed tank, the mouth of the bag is sealed in a depressurized state in the tank, and then the inside of the tank is returned to atmospheric pressure. Due to atmospheric pressure, the bag comes into close contact with the outer circumference of the winding body, and at that time, the pressure causes the varnish inside the bag to be pushed into the narrow space inside the winding body, effectively impregnating the varnish. Will be done.

[0017]

EXAMPLE An example in which the present invention is applied to a varnish impregnation process for a stator of a rotary electric machine will be described below with reference to FIGS. 1 to 8. This embodiment corresponds to claim 2.

First, with reference to FIGS. 6 to 8, a schematic structure of a stator 11 which is a winding body of an electric device will be described. The stator 11 is configured by winding a plurality of windings 13 around a stator core 12 and has a substantially annular shape as a whole. Among these, the stator core 12 is formed by laminating a plurality of thin steel plates having, for example, a ring shape and a plurality of open slots 12a formed on the inner diameter side. A slot insulator 14 is provided on the inner surface of the slot 12a.

On the other hand, the winding 13 is formed by winding a wire 15 such as a polyester imide copper wire, and a plurality of the windings 13 are accommodated in a predetermined slot 12a and fixed by a wedge 16 so that the stator core 12 is secured. It is wrapped around. In addition, the coil end portion 13a not accommodated in the slot 12a
Is shaped by a binding thread 17, and a required connection between the windings 13 is made at the coil end portion 13a, and a lead wire 18 is led out from a terminal portion of the winding 13.

The stator 11 thus constructed is subjected to a varnish impregnation treatment as will be described later, and as a result, as shown in FIG.
As shown in FIG.
An insulating layer 19 made of varnish is formed between the windings 13 and between the winding 13 and the slot 12a (slot insulator 14). With this, the heat resistance strength and vibration resistance strength of the winding wire 13 are improved, the fixing force to the stator core 12 is strengthened,
It is designed to prevent insulation deterioration.

Now, the procedure of the varnish impregnation treatment for the stator 11 will be described below with reference to FIGS. 1 to 5.

First, as shown in FIG. 4, the stator 1 constructed by winding the winding wire 13 around the stator core 12 as described above.
An inner diameter barrier member 20 is arranged on the inner peripheral portion of 1. The inner-diameter barrier member 20 has a balloon shape made of a stretchable material such as rubber, and is sealed in a state in which an appropriate amount of air is sealed in advance.

Then, the stator 11 having the inner diameter barrier member 20 arranged on the inner peripheral portion is attached to the airtight bag 21 having the upper end opened.
House inside. The bag 21 is made of, for example, a flexible plastic film, has a diameter slightly larger than the outer diameter of the stator 11, and has a sufficient length dimension.

At this time, as shown in FIG. 4, the bag 2
A required amount of solventless varnish 22, for example, is stored in the container 1. Further, in order to bring the bag 21 into close contact with the corner portion formed by the coil end portion 13a of the winding wire 13 and the stator core 12, the outer peripheral portion of the base end portion of the coil end portion 13a is
The strings 23 and 23 are wound from the outside of the bag 21. Next, the stator 1 housed in the bag 21 together with the varnish 22 in this way
1 is stored in a tank 24 for impregnating varnish. This tank 24, as shown in FIGS.
A lid 24 a is provided so as to be openable and closable via a hinge 25, and the lower portion of its side wall is connected to a vacuum pump 27 via an air passage 26.

The bag 24 is placed in the tank 24.
A heat sealer 28 is provided to seal the opening of the. The heat sealer 28 is composed of a pair of heater support bases 29 and 30 provided at positions corresponding to each other on the tank 24 and the lid 24a, and heaters 31 and 32 provided on the heater support bases 29 and 30, respectively. There is.

As shown in FIG. 1, the stator 11 is accommodated in the tank 24 as described above with the lid 24a opened, and at this time, the mouth portion 21a of the bag 21 supports the lower heater. It is arranged on the table 29 (heater 31). In this state, the inside of the tank 24 is hermetically closed by closing the lid 24a. As shown in FIG. 2, the lid 2
In the closed state of 4a, the mouth portion 21a of the bag 21 is sandwiched between the heaters 31 and 32, but is not sealed, so that air can pass therethrough.

Subsequently, the vacuum pump 27 is driven to reduce the pressure in the tank 24. At the time of this depressurization, the air in the bag 21 is also projected into the tank 24 from the mouth portion 21a.
The inside of 1 is also depressurized like the inside of the tank 24. Then, in this depressurized state, both heaters 31 and 32 of the heat sealer 28 are
The mouth portion 21a of the bag 21
Airtightly seal.

At this time, the inner diameter barrier member 20 disposed on the inner peripheral portion of the stator 11 is stretchable, so that the bag 2
When the inside of the stator 1 is decompressed and the outside becomes a negative pressure, it expands and comes into close contact with the inner peripheral surface of the stator 11 without wrinkling.

Thereafter, the vacuum pump 27 is stopped, the inside of the tank 24 is gradually opened to inject air, and the inside of the tank 24 is returned to the atmospheric pressure by opening the lid 24a. Then, as shown in FIGS. 3 and 5, the bag 2
Atmospheric pressure acts on the outer surface of the bag 1, and the bag 21 whose inside is held in a depressurized state is brought into close contact with the outer peripheral portion of the stator 11 like a vacuum packed state.

At this time, the inner diameter barrier member 20 is also in close contact with the inner peripheral portion of the stator 11 as described above, so that the varnish 22 accommodated in the bag 21 becomes
The inside and the inside of the slot 12a are forcibly impregnated. At this time, the atmospheric pressure acts from the outside, so that the varnish 22 in the bag 21 is pushed into the narrow space of the stator 11.

After that, the stator 11 is taken out from the tank 24 and is housed in a heating furnace (not shown) while being housed in the bag 21, and the varnish 2 impregnated in the heating furnace is taken out.
Heat cure 2 After heating and curing the varnish 22, the bag 21
And the inner-diameter barrier member 20 is removed. Thus, the stator 1 having the insulating layer 19 formed of the varnish 22 is formed.
1 is configured to improve the heat resistance strength and vibration resistance strength of the winding wire 13,
The fixing force to the stator core 12 is enhanced, the insulation effect is improved, and the like.

When the bag 21 and the inner diameter barrier member 20 are in close contact with the stator 11 with wrinkles in the process of the varnish impregnation process, the varnish 22 penetrates into the wrinkles. However, as a result, an extra insulating layer corresponding to the wrinkles may be formed on the surface portion of the stator 11.

However, in this embodiment, since the bag 21 is slightly larger in diameter than the stator 11, the bag 21 comes into close contact with the outer peripheral surface of the stator 11 with almost no wrinkles. The inner diameter barrier member 20 comes into close contact with the inner peripheral portion of the stator 11 without wrinkles.
Therefore, it is possible to prevent an extra insulating layer from being formed on the surface portion of the stator 11, especially on the inner peripheral portion.

As described above, according to this embodiment, the varnish 22 is put under reduced pressure on the stator 11 housed in the airtight bag 21.
Therefore, unlike the case of using the conventional dipping method or the dropping method, the varnish 22 is attached to the wire 1 of the winding 13.
It is possible to impregnate even the narrow spaces between the five or between the windings 13 and the slots 12a. Further, since the stator 11 is covered with the bag 21, it is possible to prevent the impregnated varnish 22 from flowing out.

Particularly, in this embodiment, the mouth portion 21a of the bag 21 which covers the stator 11 is sealed in the tank 24 under reduced pressure,
After that, since the inside of the tank 24 is returned to the atmospheric pressure, the bag 21 comes into close contact with the outer peripheral portion of the stator 11 by the atmospheric pressure, and at that time, the pressure causes the varnish 22 in the bag 21 to move to the stator 11. It can be pushed into a narrow space inside,
The impregnation of the varnish 22 is extremely effectively performed.

Since the balloon-shaped inner diameter barrier member 20 made of a stretchable material is arranged on the inner peripheral portion of the stator 11, the bag 4 is folded back to cover the inner peripheral portion of the stator 3. Therefore, unlike the case where an extra insulating layer may be formed due to the wrinkles of the bag 4, the inner diameter barrier member 2
It is possible to bring 0 into close contact with the inner peripheral surface of the stator 11 without wrinkles, and as a result, it is possible to prevent an extra insulating layer from being formed on the inner peripheral portion of the stator 11.

In the above embodiment, the sealed tank 24 is used to depressurize the inside of the tank 24 to carry out the impregnation treatment. However, the mouth 21a of the bag 21 is directly connected to the depressurization source. Even if the inside of the bag 21 is depressurized, the same effect can be obtained. In addition, the process of heating and curing the varnish 22 may be performed by using a method such as induction heating regardless of the heating furnace.

Besides, even if the varnish 22 is not housed in the bag 21 in advance, a seat for varnish injection is formed in a part of the bag 21, and after the pressure is reduced, the varnish 22 is injected into the bag 21 for impregnation. The present invention can be carried out by appropriately changing it without departing from the scope of the invention.

[0039]

As is apparent from the above description, according to the method for impregnating varnish for electric equipment of the present invention, the so-called vacuum packing method is used in which the winding body is covered with the airtight bag and the varnish is impregnated. The varnish can be impregnated into a narrow space between the wires of the winding wire or between the winding wire and the iron core.
It is possible to prevent the varnish once impregnated from flowing out, and it is possible to prevent the formation of an extra insulating layer on the inner peripheral portion of the winding body, which is an excellent practical effect. It plays.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an embodiment of the present invention, showing a state where a stator is housed in a tank.

FIG. 2 is a view corresponding to FIG. 1 showing a state where the tank is sealed.

FIG. 3 is a view corresponding to FIG. 1 showing a state in which the inside of the tank is returned to atmospheric pressure after depressurization.

FIG. 4 is a front view showing a state in which a stator is housed in a bag, with a part thereof being cut vertically.

FIG. 5 is a front view showing a state in which the bag is in close contact with the stator, with a part being cut vertically.

FIG. 6 is a perspective view of a stator.

FIG. 7 is an enlarged perspective view of a coil end portion of a stator.

FIG. 8 is a partial cross-sectional view of the stator.

FIG. 9 is a view corresponding to FIG. 4 showing a conventional example.

FIG. 10 is a view showing the folding back principle of the bag.

[Explanation of symbols]

In the drawings, 11 is a stator (winding body), 12 is a stator core (iron core), 12a is a slot, 13 is a winding, 13a is a coil end portion, 19 is an insulating layer, 20 is an inner diameter barrier member,
21 is a bag, 21a is a mouth part, 22 is a varnish, 24 is a tank, 24a is a lid, 27 is a vacuum pump, and 28 is a heat sealer.

Claims (2)

[Claims] 1. An airtight seal, comprising an annular winding body including an iron core and a winding provided on the iron core, and a balloon-shaped inner-diameter barrier member made of a stretchable material disposed on an inner peripheral portion thereof. A method for impregnating a varnish of an electric device, characterized in that the winding body is housed in a bag, the inside of the bag is depressurized, and the winding body is impregnated with the varnish housed in the bag under the depressurized state. 2. An annular winding body composed of an iron core and a winding provided on the iron core, and a balloon-shaped inner diameter barrier member made of a stretchable material is arranged on an inner peripheral portion of the annular winding body and the whole is airtight. In a state of being accommodated in a bag, accommodated in a closed tank, after depressurizing the inside of the tank, the mouth of the bag is sealed in this state, and thereafter, by returning the inside of the tank to atmospheric pressure,
A method for impregnating a varnish of an electric device, characterized in that the winding body is impregnated with the varnish contained in the bag.