JP5734110B2 - Method for impregnating varnish of winding body for rotating electrical machine and winding body for rotating electrical machine manufactured by the method - Google Patents

Description

  The present invention relates to a varnish impregnation treatment method for a coil which is a winding body for a rotating electrical machine such as a general industrial and consumer motor, a generator, etc., and a coil which is a winding body for a rotating electrical machine manufactured by varnishing by this method. It is about.

Conventionally, in the stator coil formed by winding a conductor around the iron core of a rotating electrical machine, the rotor coil, etc., in addition to improving the insulation performance, the gap between the conductors is filled to improve the heat transfer from the coil to the iron core. In order to improve and improve the heat dissipation characteristics of the coil, varnish impregnation treatment is performed.
As such a varnish impregnation method, a dipping impregnation method in which a coil is immersed in a thermosetting resin varnish to infiltrate the varnish, a dripping impregnation method in which a varnish is dropped into the coil and impregnated, or the coil is accommodated in a vacuum container Then, there is a vacuum impregnation method in which the coil is immersed in the varnish or the varnish is dropped and impregnated in a state where the inside of the container is decompressed.
However, the coil impregnated with varnish by these methods is then heated in a heating furnace to cure the varnish. In this heating process, the varnish viscosity decreases once before the coil temperature reaches the varnish curing temperature. The varnish flows out of the coil, and there is a problem that the insulation performance and the heat dissipation performance of the coil deteriorate.For this improvement, when the coil is immersed in the varnish, the coil is gelated by overheating the coil. A method for preventing the varnish from flowing out after impregnation (for example, Patent Document 1), or a powder varnish treatment is performed on the coil surface to form a non-permeable coating, and then a solvent is not contained in the coating by a vacuum pressure impregnation apparatus. A method of filling a varnish and then heat-curing the solventless varnish filled in the coating (for example, Patent Document 2) has been proposed.

JP-A-61-214749 Japanese Patent Laid-Open No. 06-153468

According to the varnish impregnation method of Patent Document 1, since the varnish is gelled during the immersion, the varnish is not lowered during the heat curing, and the varnish can be prevented from flowing out. Moreover, according to the varnish impregnation method of patent document 2, since a varnish is impregnated in a non-permeable film, the outflow of the varnish at the time of heat curing can also be prevented.
However, in the technique disclosed in Patent Document 1, since the coil is energized and heated while the varnish is immersed, the deterioration of the varnish proceeds due to heat storage, and the pot life (pot life) is shortened, resulting in a decrease in material yield. there were. Further, the technique of Patent Document 2 requires a masking process for creating an opening for impregnating the solventless varnish, a process for attaching the powder varnish, and a process for melting and fixing the powder varnish, which increases the number of steps and increases the number of steps. The material cost also increases due to the varnish, resulting in a problem that the manufacturing cost increases.

  The present invention has been made to solve the above-described problems, and suppresses an increase in manufacturing cost without passing through an extra step and prevents the varnish from flowing out during heat curing. The object is to obtain a winding body for a rotating electrical machine that is excellent in insulation and heat dissipation manufactured by impregnating a varnish with this treatment method.

A first aspect of the present invention is a varnish impregnation treatment method for a rotating electrical machine winding body formed by winding a plurality of layers of conductors, a preheating process for preheating the rotating electrical machine winding body, and a preheated rotating electrical machine A varnish impregnation step for dripping and impregnating the varnish on the winding body, and a heat curing step for curing the varnish,
The varnish impregnation step has a first step of dropping and impregnating A varnish and a second step of dropping and impregnating B varnish following the first step, and the curing temperature of A varnish and B varnish is A varnish. with a curing temperature> curing temperature of B varnishes, preheating temperature of the rotary electric machine winding body in the preheating step, at least the curing temperature of the B varnish, and with those lower than the curing temperature of the a varnish, the By causing the B varnish to gel only at the surface layer portion of the rotating electrical machine winding body in the step 2, the outflow of the A varnish from the inside of the rotating electrical machine winding body is prevented in the heat curing step.

  The second invention is a winding body for a rotating electrical machine manufactured by the varnish impregnation method according to the first invention.

  Since the varnish impregnation method for a winding body for a rotating electrical machine according to the first invention has the above-described curing temperature of the varnish and includes the above-described steps, it affects the pot life of the varnish. In addition, varnish outflow during heat curing can be prevented without requiring an extra step, and the yield of the varnish used can be improved. As a result, the consumption of varnish can be reduced and the manufacturing cost can be reduced.

  Since the winding body for a rotating electrical machine according to the second invention is manufactured by the method according to the first invention, a winding body for a rotating electrical machine excellent in insulation and heat dissipation can be obtained at low cost. There is an effect.

4 is a schematic diagram showing a varnish impregnation step according to Embodiment 1. FIG. It is sectional drawing which shows the osmosis | permeation state to the coil after dripping the A varnish by Embodiment 1. FIG. It is sectional drawing which shows the osmosis | permeation state to the coil after dripping B varnish after A varnish dripping by Embodiment 1. FIG. FIG. 3 is a diagram illustrating a varnish impregnation treatment step for a winding body according to the first embodiment. It is a figure which shows the comparison of each Example by Embodiment 1. FIG. FIG. 3 is a diagram illustrating an apparatus configuration of a heat dissipation characteristic measurement system for a winding body according to the first embodiment. It is a figure which shows the thermal radiation characteristic measurement result of each Example by Embodiment 1. FIG. It is sectional drawing which shows the varnish penetration state to the winding body by the comparative example 2 by Embodiment 1. FIG. It is sectional drawing which shows the varnish penetration | invasion state to the coil | winding body by the comparative example 3 by Embodiment 1. FIG.

Embodiment 1 FIG.
Hereinafter, a varnish impregnation method for a rotating electrical machine winding body (hereinafter referred to as a winding body) according to Embodiment 1 of the present invention will be described with reference to the drawings.
FIGS. 1A and 1B are schematic diagrams showing a varnish impregnation step in the first embodiment. Here, in the first embodiment, the A varnish 4 having a curing temperature of 155 ° C. from the plurality of A varnishes 4 having a curing temperature of 155 ° C. to 185 ° C. and the plurality of B having a curing temperature of 125 ° C. to 145 ° C. Among the varnishes 5, B varnish 5 having a curing temperature of 135 ° C. is used. As shown in FIGS. 1A and 1B, the winding body 3 includes an iron core 1 and a coil 2. The coil 2 is formed by winding a plurality of layers of a conductor such as an enameled wire or a polyesterimide wire directly around the iron core 1.
The winding body 3 is subjected to varnish impregnation after preheating in a furnace (not shown) at a temperature of 135 ° C. in order to remove the adsorbed moisture and distortion of the conductor coating layer generated during winding. The temperature adjustment of the winding body 3 in the preheating step is set to 135 ° C., which is equal to or higher than the curing temperature (135 ° C.) of the B varnish 5 and lower than the curing temperature (155 ° C.) of the A varnish 4. Has been made.

As shown in FIG. 1B, the A varnish 4 is dropped through the nozzle 11 and penetrates into the coil 2 as shown in FIG. The B varnish 5 is dropped through the nozzle 11a and penetrates into the coil 2.
FIG. 2 shows a cross-sectional view of the state of penetration of the A varnish 4 into the winding body 3 after dropping the A varnish 4. As shown in FIG. 2, since the preheating temperature (135 ° C.) of the winding body 3 is lower than the curing temperature (155 ° C.) of the A varnish 4, the central portion of the coil 2 does not gel at the surface layer portion 2 a of the coil 2. Penetration up to 10.
FIG. 3 shows a sectional view of the winding body 3 in which the B varnish 5 is dropped and penetrated after the A varnish 4 is dropped. Since the varnish 5 having a preheating temperature of 135 ° C. and a curing temperature of 135 ° C. is adopted, the surface layer 2a does not penetrate to the central portion 10 of the coil 2 as shown in FIG. That is, it gels in approximately 2 to 3 layers from the surface layer of the coil 2. After continuously dripping and impregnating the A varnish 4 and the B varnish 5 in this manner, the winding body 3 is heated at the curing temperature of the A varnish 4 to perform a varnish impregnation treatment. This series of steps will be described later.

Next, examples based on the first embodiment will be described.
After winding a conductor having a wire diameter of 1.05 mmφ around the iron core 1 to form a winding body 3 having a coil 2 with a space factor of 87%, preheating in a hot air drying furnace at a temperature setting of 150 ° C. for 2 hours, The A varnish 4 was dropped (hereinafter referred to as the first step) onto the winding body 3 adjusted to be heated at around 135 ° C., and then the B varnish 5 was dropped (hereinafter referred to as the second step). Thereafter, it was heated in a hot air drying furnace at 175 ° C. for 4 hours to cure the A varnish 4 and B varnish 5 to obtain an impregnated winding body 3. This series of steps is shown in FIG.
The A varnish 4 was adjusted as follows.
Main agent: 49 parts by weight of epoxy polyester, cross-linking agent: 49 parts by weight of 2-hydroxyethyl methacrylate, polymerization initiator: 1 part by weight of dicumyl peroxide, curing agent: 1 part by weight of zinc octylate using a propeller-type stirrer After stirring for a period of time, the mixture was left to degas until no bubbles were observed. The curing temperature of the A varnish 4 is 175 ° C.
Moreover, B varnish 5 was adjusted as follows.
Main agent: 59 parts by weight of epoxy acrylate, cross-linking agent: 40 parts by weight of 2-hydroxyethyl methacrylate, polymerization initiator: t-butylperoxy-2-ethylhexanoate: 1 part by weight is stirred with a propeller-type stirrer for 1 hour. After that, it was left to degas until no bubbles were confirmed visually. The curing temperature of the B varnish 5 is 135 ° C.

(Comparative Example 1)
In the varnish impregnation step, only the A varnish 4 as the first step was dropped and the B varnish 5 as the second step was not dropped. Body 3 was obtained.
(Comparative Example 2)
In the varnish impregnation step, only the B varnish 5 of the second step was dropped and the A varnish 4 was not dropped, and the same process as in the example was performed to obtain the impregnated winding body 3.
(Comparative Example 3)
In the first step of impregnating the varnish, instead of the A varnish 4 of the embodiment, the wound body 3 subjected to the impregnation treatment by performing the same steps as in the embodiment except that the C varnish 9 prepared as follows was dropped. Obtained.
Main component: 50 parts by weight of unsaturated polyester, crosslinking agent: 49 parts by weight of 2-hydroxyethyl methacrylate, polymerization initiator: 1 part by weight of 1,1-di (t-butylperoxy) -2-methylcyclohexane After stirring for 1 hour, the mixture was left to deaerate until no bubbles were observed. The curing temperature of the C varnish 9 is 142 ° C.

  FIG. 5 collectively shows preheating process conditions, varnish impregnation process conditions, and varnish curing process conditions in Examples, Comparative Example 1, Comparative Example 2, and Comparative Example 3.

Next, the varnish adhesion amount, the insulation performance, and the heat dissipation performance of the windings of the winding bodies 3 obtained in Examples, Comparative Example 1, Comparative Example 2, and Comparative Example 3 were evaluated. The amount of varnish adhesion was determined from the weight difference between the winding bodies 3 before and after the impregnation treatment. As for the insulation performance, the value of the dielectric loss tangent between the coil 2 and the iron core 1 was measured as a representative value. The measurement conditions were AC 2500 V, 60 Hz, and measurement was performed with a tan δ measuring device DAC-ASM-7 manufactured by Soken Denki Co., Ltd. Regarding the heat dissipation characteristics, FIG. 6 shows the configuration of the measurement system. With the heat sink 6 attached to the iron core 1, a voltage of 100 V AC and 60 Hz is applied to the coil 2 from the AC power source 7, and the resistance of the coil 2 is measured initially and for 1 hour after being energized by the resistance meter 8. The temperature rise of the coil 2 was determined according to the equation.
θ = θ2-θα = (R2 / R1-1) × (235 + θ1) + (θ1-θα) [° C.]
θ: Temperature rise value of coil 2, θ1: Winding temperature at initial resistance measurement, θ2: Temperature of coil 2 after test θα: Room temperature after test, R1: Initial resistance, R2: Resistance after test Each measurement result is shown collectively.

The amount of varnish attached was 24.2 g in the example, and almost the total amount of 25 g of A varnish 4 and B varnish 5 dropped in the first step and the second step was attached to the coil 2 after curing. I understand that. On the other hand, in Comparative Example 1, 13.8 g, and about 45% of the A varnish 4 dropped in the varnish impregnation step flows out of the coil 2 in the curing step. In Comparative Example 2, the amount of adhesion is very small at 9.4 g.
FIG. 8 is a cross-sectional view of the winding body 3 obtained in Comparative Example 2. The B varnish 5 adheres only to the surface layer 2a (2 to 3 layers from the surface) of the coil 2, and almost no permeation into the center 10 of the coil 2 is observed. This is because the B varnish 5 dripped onto the coil 2 gels at the surface layer portion 2a and inhibits the penetration of the B varnish 5 dripped after that into the coil 2. In Comparative Example 3, the amount of varnish attached is larger than that in Comparative Examples 1 and 2 with 19.8 g, but is smaller than that in Examples.
FIG. 9 shows a cross-sectional view of the winding body 3 obtained in Comparative Example 3. As can be seen from FIG. 9, the C varnish 9 does not penetrate to the central portion 10 of the coil 2, and a gap is generated in the central portion 10 of the coil 2. This is because the curing temperature of the C varnish 9 is 142 ° C., whereas the curing temperature of the B varnish 5 is 135 ° C. and the temperature difference is within 10 ° C. Because the temperature was adjusted to 135 ° C., when the C varnish 9 was dropped, a part of the C varnish 9 was gelled and the penetration into the coil 2 was inhibited.

Regarding the dielectric loss tangent, Comparative Example 1 is 3.4%, Comparative Example 2 is 4.9%, and Comparative Example 3 is 2.9%, whereas in Example, the minimum value is 2.2%. . This indicates that in Comparative Example 1, Comparative Example 2 and Comparative Example 3, there is an increase in the leakage current between the coil 2 and the iron core 1 due to the smaller amount of varnish adhesion compared to the example.
Further, regarding the temperature rise, Comparative Example 1 is 58.2 ° C., Comparative Example 2 is 61.4 ° C. and Comparative Example 3 is 55.9 ° C., whereas in Example, it is 51.2 ° C., which is the minimum value. It is. This is because the A varnish 4 is sufficiently impregnated to the central portion 10 of the coil 2 in the first step and the second step in the embodiment, and the A varnish 4 flows out of the coil 2 in the subsequent curing step. This shows that the heat transfer between the coil 2 and the iron core 1 and the heat dissipation of the coil 2 have been improved by preventing and ensuring a sufficient amount of varnish adhesion in the coil 2 after curing.
From the above results, in the example using the varnish impregnation method based on the first embodiment, the varnish impregnation step is performed in the coil 2 in the first and second steps described above at low cost without passing through an extra step. A varnish 4 and B varnish 5 are sufficiently infiltrated, and the varnish hardening process at 175 ° C. shown in FIG. 4 prevents the varnish from flowing out of the coil 2, ensuring a sufficient amount of varnish adhesion and insulating performance. It can be seen that the winding body 3 having excellent heat dissipation performance was obtained.
In addition, although the example of composition of A varnish 4 and B varnish 5 was shown in the Example, it is not limited to these, What kind of composition is sufficient as long as the performance requirements described in this Embodiment 1 are satisfy | filled. It can be used.

Moreover, in this Embodiment 1, although the varnish impregnation method of the winding body 3 provided with the direct winding coil 2 formed by winding a conductor directly around the iron core 1 was explained, the coil 2 is attached to the iron core 1 without being limited to this example. Instead of direct winding, a so-called indirect winding coil 2 formed by winding with a dedicated tool may be used, and the indirect winding coil 2 may be impregnated with a varnish.
Furthermore, although the method in which the A varnish 4 and the B varnish 5 are impregnated through the nozzles 11 and 11a has been described, other methods such as an immersion impregnation method and a vacuum impregnation method may be used. The varnish impregnation method according to the first embodiment can be applied to general-purpose IPM motors, permanent magnet embedded motors, and various types of rotating electrical machines.

  1 Iron core, 2 coils, 2a Surface layer part, 3 Winding body, 4 A varnish, 5 B varnish.

Claims (6)

A varnish impregnation method of a rotating electric machine winding body formed by winding a plurality of layers of conductors, and the preheating step of preheating the rotary electric machine winding body, the winding body for the pre-heated rotary electric machine A varnish impregnation step for dripping and impregnating the varnish, and a heat curing step for curing the varnish,
The varnish impregnation step, dropwise A varnish, a first step of impregnating, subsequently dropping the B varnish to said first step, a second step of impregnating, curing of the A varnish and the B varnish The temperature is the curing temperature of the A varnish> the curing temperature of the B varnish, and the preheating temperature of the winding body for the rotating electrical machine in the preheating step is equal to or higher than the curing temperature of the B varnish and from the curing temperature of the A varnish. And the B varnish is gelled only at the surface layer portion of the rotating electrical machine winding body during the second step, so that the inside of the rotating electrical machine winding body in the heating and curing process is reduced. The varnish impregnation method for the winding body for a rotating electrical machine, wherein the outflow of the A varnish is prevented from occurring. The curing temperature of the A varnish dropped and impregnated in the first step is at least 10 ° C higher than the curing temperature of the B varnish dropped and impregnated in the second step. A varnish impregnation treatment method for a winding body for a rotating electrical machine. The rotating electrical machine according to claim 1, wherein the rotating electrical machine winding body core and coil or the electric rotating machine winding body which is wound directly on the core is to either indirect wound coil Varnish impregnation treatment method for winding body. The varnish impregnation method for a winding body for a rotating electrical machine according to claim 3, wherein the A varnish is impregnated in the coil, and the B varnish is impregnated in a surface layer portion of the coil. A winding body for a rotating electrical machine manufactured by the varnish impregnation treatment method according to claim 1. Rotation of claim 5, wherein the rotating electrical machine winding body, the core and coil are wound directly on the core or the rotary electric machine winding body, characterized in that as one of the indirect wound coil Winding body for electric machine.

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