JP3158025B2 - Rotating machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating machine used as a generator or a motor.

[0002]

2. Description of the Related Art Conventionally, plastic films are required to have high insulation performance, and as parts and members requiring reliability, electronic and electrical equipment such as cable coating insulation, printed wiring boards, slot insulation of rotating machines, and the like. , Film capacitors and other electronic components. The history of the development of such plastic insulation films is as follows:
Film development of plastic materials having excellent environmental resistance has been promoted, and synthesis and development of engineering plastics having particularly excellent heat resistance have been promoted and put to practical use.

As an insulating material for a rotating machine, polyethylene terephthalate (PE) is used as a general-purpose film having heat resistance.
Polyester film such as T) has excellent insulation performance,
From the viewpoints of heat resistance, moldability, cost, and the like, they have been used for slot insulation, slot spacers, wedges, and the like of a slot insulation portion between an iron core and a field coil. When higher heat resistance is required, polyester films have been used in combination with aramid paper.

[0004]

In recent years, in electronic equipment for storing a large amount of information corresponding to a highly information-oriented society, processing the data at a high speed, and transmitting the data at a high speed, high performance is required for plastic materials. I have. In particular, low electric constant and low dielectric loss tangent are required as electrical characteristics corresponding to high frequency. In particular, in the case of a rotating machine such as an electric motor, inverter control that can be precisely controlled is often performed in order to achieve high efficiency and high functionality. As a result, an increase in leakage current of a high-frequency component in the insulating member occurs. Therefore, it is required to reduce the dielectric constant as an electrical characteristic to prevent the increase. To reduce the leakage current, increasing the thickness of the slot insulation is also effective.However, this method reduces the utilization efficiency of the iron core slot, and as a result, the size, weight,
Important properties such as efficiency must be sacrificed.

In order to solve this problem materially,
Conventionally, it was necessary to select a material having a low dielectric constant. However, the dielectric constant of a substance usually depends on the material. For example, the dielectric constant of a typical plastic is about 3.1 for polyethylene terephthalate (PET), an engineering plastic having excellent heat resistance, and polyimide (P
I) is about 3.3, about 2.3 for polyethylene with low dielectric constant (PE), and about 2.1 for polytetrafluoroethylene (PTFE) with the lowest dielectric constant. However, there is a limit in the dielectric constant of the bulk physical properties of such plastics, which are determined from the molecular structure and therefore have a unique value in each material. Generally, engineering plastics having excellent heat resistance, such as PET, contain a large amount of aromatic components and have a high density, so that many of them have a high dielectric constant.

Further, when selecting a material from the dielectric constant, it is necessary to satisfy other physical properties such as workability and heat resistance. Fluoroplastics such as PTFE, which are excellent in terms of low dielectric constant, have sufficient heat resistance, but have high costs and have problems with moldability. For olefin resins such as PE, heat resistance up to about 100 ° C is not sufficient. Was.

According to the present invention, in order to cope with a higher frequency of the control of the rotating machine as described above, the present invention has a low dielectric constant not more than a value determined by the physical properties of the bulk, and is excellent in heat resistance, workability and economy. It is an object of the present invention to obtain a rotating machine with reduced high-frequency leakage power by using a plastic film as a slot insulating material.

[0008]

In order to achieve the above object, according to the present invention, a fluorinated resin film is sandwiched between two polyester films at a slot insulating portion between an iron core of a rotating machine and a field coil. Consists of a film.

When the polyester film having the fluororesin is formed by multilayering the polyester film and the fluorinated resin film, the effect of reducing the leakage current at a high frequency of the rotating machine is exhibited. With this configuration, even when a fluorinated resin film having low moldability is used, the same workability as that of a polyester film can be obtained.

Further, when the polyester film having the fluororesin is formed by laminating the polyester film and the fluorinated resin film to form a multilayer, the effect of reducing the leakage current at a high frequency is sufficiently exhibited.

Further, even when the polyester film having the fluororesin is formed by dispersing the fluorinated resin in the polyester film, the effect of reducing the leakage current at a high frequency of the rotating machine is exhibited.

When at least one of the polyester resin and the fluorinated resin is porous, a slot insulating portion having a lower dielectric constant can be formed.

When the dielectric constant of the polyester film having the fluororesin constituting the slot insulating portion is 2.5 or less, excellent effects can be obtained as compared with the polyester film alone. Furthermore, in order to obtain a rotating machine with excellent performance,
The effect can be obtained by forming a polyester film having a fluororesin so as to have a dielectric constant of 2 or less and using it for the slot insulating portion.

Here, the permittivity varies with frequency, but it is sufficient to compare the average value of the permittivity at least in the frequency range from 60H to 1 MHz. Further, the heat-resistant temperature may have a condition of a continuous heat-resistant temperature, and may be Y or more in the heat-resistant category of the IEC standard.

By the way, the electrical properties required of plastic materials in response to higher frequencies include low dielectric constant, low dielectric loss tangent, and high dielectric strength. These needs are
The importance of insulating materials used for electrical equipment is increasing because the following relationship is established.

When a plastic film is used for an insulating part of an AC device, the power loss Ploss leaking from the insulating part is represented by a frequency f and a relative permittivity ε as shown in the following equation (1).
r is proportional to the product of the dielectric loss tangent tan δ. Therefore, the power loss increases as the frequency increases. To prevent this, it is necessary to lower the relative dielectric constant and the dielectric loss tangent. The same applies to the following, but it is necessary that the change in the dielectric constant and the dielectric loss tangent be small in the used frequency range because the dielectric constant and the dielectric loss tangent have different values depending on the frequency.

[0017]

## EQU1 ## Ploss∝f 絶 縁 εr ・ tan δ In the case of the insulating part of a rotating machine, the structure of the general slot insulating part shown in FIG. A coil-coated insulating portion 3 such as enamel and a film insulating portion 4 also having an effect as a spacer are provided between the core portion 1 and the core portion 1. FIG. 2 shows an equivalent circuit for the leakage of the alternating current between the field coil 2 and the iron core 1. At this time, the impedance Z of the leakage current is expressed by Expression (2).

[0018]

## EQU2 ## Z = Z₀ + Z₁ = 1 / (G₀+ JωC₀) + 1 / (G₁+ JωC₁Here, j = √ (−1), angular frequency ω = 2πf, and f is AC
Frequency, Z₀, G₀, C ₀Is the coil insulation
Impedance, conductance and capacitance
, Z₁, G₁, C₁Each is a slot insulating film
Insulation impedance, conductance, capacitor
It is. The square value of the magnitude of this impedance Z
Is shown in equation (3).

[0019]

| Z | ² = ｛G ₀ / (G ₀ ² + ω ² C ₀ ² ) + G ₁ /
_{^{(G 1 2 + ω 2 C}} 1 2)} 2 + ω 2 · {C 0 / (G 0 2 + ω 2 C 0 2) +
In ^{_{C 1 / (G 1 2 +}} ω 2 C 1 2)} 2 ( number 3), when the dielectric loss tangent tanδ ₁ = G ₁ / ωC ₁ film insulating portion of the slot insulator is less than 1, the frequency constant, i.e. omega Is constant, the magnitude of the impedance Z monotonically decreases as the value of the dielectric constant ε ₁ of the film insulating portion increases and the capacitance C ₁ increases. Therefore, in general, in the case of a plastic film, tanδ <
Since the relationship of 1 is satisfied, the impedance increases as the dielectric constant of the film decreases and the dielectric loss tangent decreases, and the leakage current in the slot insulator of the rotating machine decreases.

Not only the problem of increasing the frequency but also the AC breakdown voltage Ebd of the plastic material is experimentally known to be a relational expression expressed by the following expression (4). The relative dielectric constant is low, and the dielectric loss tangent is low. It is known that the smaller the material is, the higher the dielectric strength is. Therefore, the reduction of the dielectric constant of the material with the increase in the frequency is an approach that can obtain the effect of improving the insulating property. In the equation (4), A and B are constants, and ρv is a volume resistivity.

[0021]

[Equation 4] Ebd = A + B · log (ρv / (εr · tan δ)) As described above, if a material having a low dielectric constant is selected as the insulating film used for the slot insulating portion, a leakage current accompanying a higher frequency of the device is obtained. Can be reduced, but there is a problem in selecting a material. That is, when considering the dielectric constant of a plastic material, the dielectric constant of a substance is determined by its molecular structure, and is expressed by the Clausius-Mossotti equation of equation (5).

[0022]

Εr = (1 + 2a) / (1-a) Here, a in the expression (5) is a = Pm / Vm, Pm is molar polarization, Vm is molar specific volume, and It is determined by the type of each functional group in the molecular structure, its polarizability, and the symmetry of the molecule. Therefore, the dielectric constant of a substance is determined as a unique value. Among the bonds in the molecule, there is a CF bond as a bond having a small polarizability, and a fluorinated resin having this CF bond exhibits a low dielectric constant. Among the fluorinated resins, PTFE having only CF bond and having symmetry
Has the lowest dielectric constant among plastic materials, but the dielectric constant of PTFE is about 2.1, and there is a lower limit in the choice of material. In addition, fluorinated resins generally have problems such as low moldability, and have problems such as tearing when inserted into the slot insulating portion. As described above, other characteristics such as heat resistance and moldability for being incorporated into the slot portion are required, so that it cannot be dealt with by simply replacing the material.

Therefore, a feature of the present invention is that a polyester resin and a fluorinated resin are compounded using polyester as a base film, which has been conventionally used for a slot insulating portion between an iron core of a rotating machine and a field coil. It is to constitute a rotating machine using a polyester film having a fluororesin. As a method of compounding the polyester resin and the fluorinated resin, a method of forming a multilayer of the polyester film and the fluorinated resin film and a method of dispersing the fluorinated resin in the polyester film are suitable.

The dielectric constant of a polyester film having a fluororesin in which a polyester film and a fluorinated resin film are multi-layered and compounded is reduced by a fluorinated resin having a dielectric constant lower than that of polyester (Equation 6). ) Expression.

[0025]

Εf = ε (F) · ε (E) · (dF + dE) / (ε
(F) · dE + ε (E) · dF) Here, εf is the dielectric constant of the polyester film having the fluororesin constituted in the present invention, and ε (F) and dF are each multiplied by the dielectric constant of the fluorinated resin. Total thickness, ε (E), dE
Is the dielectric constant of the polyester resin and the total thickness of the multilayered resin. By using this multi-layered composite film, the fluorinated resin, which had a relatively low dielectric constant but did not have the moldability required for inserting the film into the slot insulating portion, together with the polyester film, is also used. The slot insulating portion can be formed with a sufficient degree of moldability. In particular, excellent effects were obtained by sandwiching a fluorinated resin film between polyester films or alternately laminating both. Further, by laminating both, more stable moldability was obtained.

The dielectric constant of a polyester film having a fluororesin compounded by dispersing a fluorinated resin in a polyester film is reduced by a fluorinated resin having a dielectric constant lower than that of polyester (Equation 7). ) Expression. In this configuration, since the fluorinated resin portion having a small dielectric constant is present in the polyester film of the slot insulating portion, the dielectric constant of the entire film is lower than the bulk dielectric constant of only the polyester film. The relationship is approximately expressed by the following equation (7).

[0027]

Εf = (F) ・ VF + ε (E) ・ (1-VF) where εf is the dielectric constant of the polyester film having the fluororesin constituted by the present invention, and ε (F) is the dispersed fluorine. Ε (E) is the relative dielectric constant of the polyester resin. VF is the volume ratio of the space portion occupied by the dispersed fluorinated resin to the whole film.

Furthermore, if at least one of the composited polyester resin and the fluorinated resin has a porous structure, the dielectric constant of the film can be further reduced, and the rotating machine with less power loss in the slot insulating portion can be obtained. Can be configured. That is, since there is a space portion in the film insulating portion of the slot insulating portion which has a gas whose dielectric constant is much smaller than that of the solid portion, the dielectric constant of the entire film decreases. The relationship of the decrease in the dielectric constant due to the porosity of each resin is approximately expressed by Equation (8).

[0029]

Ε = ε (g) · Vg + ε (b) · (1−Vg) where ε is the dielectric constant of the porous resin, and ε (g) is the dielectric constant of the gas in the space where the gas exists. (1 for air), ε (b)
Is the bulk dielectric constant of the resin material. Vg is the volume ratio of the space where gas is present to the entire resin part, and corresponds to the porosity in the case of porous plastic. Further, when the film has a porous structure, even if it contains a fluorinated resin, it has sufficient characteristics in terms of moldability in forming the slot insulating portion. It is suitable that the porous structure has an average pore diameter of about 10 to 100 μm and a porosity of 10 vol% or more. At this time, if the porous structure is a foamed structure having closed cells, the effect can be exhibited in order to prevent intrusion of liquid when the rotating machine is used by impregnating it with a refrigerant liquid or an oil liquid.

[0030]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 shows an example of a fluororesin-containing polyester film used in the rotating machine of the present invention. this is,
The fluorinated resin film 6 having a low dielectric constant is sandwiched between two polyester films 5. In this figure, the layers are simply superimposed to form a multilayer, but as a method of bringing them into close contact, they may be laminated via a heat-resistant adhesive layer, or they may be laminated together by applying heat and melt-extruding. It may be constituted by. When the adhesive layer is provided, it is necessary to use a heat-resistant resin component, and a polyester-based heat-resistant adhesive is preferable.
With this configuration, an insulating film having a low dielectric constant and excellent in electrical characteristics and moldability can be obtained. Then, as an insulating film, it is used by inserting it into the film insulating portion 4 of the slot insulating portion of the rotating machine shown in FIG.

The thickness of the film actually used is generally in the range of 0.1 μm to 1 mm, but is generally 100 μm to 500 μm.
Often used as m. The thickness of the fluorinated resin film 6 in the range of 1 μm to 100 μm is suitable as the thickness at which the moldability is obtained when the multilayer is formed, and the workability is obtained according to the thickness and the desired dielectric constant is obtained. The thickness of the polyester film is adjusted so that it can be used.

Next, another embodiment of the polyester film having a fluorine resin used in the rotating machine of the present invention is shown in FIG. As in FIG. 3, a plurality of fluorinated resin films 6 and polyester films 5 having a low dielectric constant are alternately sandwiched. With this configuration, the effect of improving the moldability of the thin-layer fluorinated resin film 6 by multi-layering is exhibited. The thickness of the film can be selected within the range of the thickness described above. In particular, a film having a thickness of 5 μm to 25 μm of the fluorinated resin film 6 having a thickness of
A configuration in which a plurality of polyester films 5 of m to 25 μm were laminated was suitable.

FIG. 5 shows a reference example . A dispersion in which a dispersion 8 of fluorinated resin fine powder is dispersed in a polyester base film 7 is used. Further, this is stretched and oriented to form pores 9 in the polyester film using the dispersion 8 as foam nuclei. This film is used as an insulating film by inserting it into the film insulating portion 4 of the slot insulating portion of the rotating machine shown in FIG. In this configuration,
The dielectric constant of the polyester film is reduced by dispersing the fluorinated resin, and the dielectric constant is further reduced by the formation of holes, so that leakage current due to the slot insulation of the rotating machine is more efficient Decline. Further, if the fluorinated resin powder used as the foam nucleus is a porous structure, the dielectric constant is further reduced and the effect is obtained.

The formed pores may be open cells in which the respective pores are continuously connected or independent closed cells. However, in order to impregnate the liquid or prevent the influence of humidity, etc., the closed holes may be used. It is better to be. The closed cells preferably have a closed cell ratio of 80% or more. In particular, the porous structure has an average pore diameter of 10 μm or less and a porosity of 10 vol.
% Or more, a slot structure of a rotating machine can be provided.

Specific polyesters include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PE).
General polyester films such as aromatic polyesters such as N) and crosslinked polyesters for improving heat resistance can be used.

Specific examples of the fluorinated resin include polytetrafluoroethylene (PTFE), which is a homopolymer of tetrafluoroethylene (TFE), and polytetrafluoroethylene, which is a polymer obtained by copolymerizing TFE with perfluoroalkyl vinyl ether. -Perfluoroalkylvinyl copolymer (PFA), polytetrafluoroethylene-polyhexafluoropropylene copolymer (FEP), which is a copolymer of TFE and hexafluoropropylene, and poly, which is an alternating copolymer of TFE and ethylene Tetrafluoroethylene-ethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE) which is a homopolymer of ethylene trifluoride chloride,
Polyvinylidene fluoride (PVDF), a homopolymer of vinylidene fluoride, polytrifluoroethylene-ethylene copolymer (ECTFE), polyvinyl fluoride (PV
F), a fluorine-containing resin commercially available such as a cyclopolymerized polymer of perfluoroalkenyl vinyl ether (CYTOP, product name of Asahi Glass) can be used. (Example 1) Two PET films having a film thickness of 125 μm and a dielectric constant of 3.2 were laminated with two PTFE films having a film thickness of 50 μm and a dielectric constant of 2.1 to form a multilayer structure. A film having the configuration shown in FIG. 3 was inserted into the iron core portion of the rotating machine and the slot insulating portion of the field coil to produce a stator of the motor. With this configuration, no extreme breakage of the PTFE film occurred during processing.

When the dielectric constant between the field coil and the iron core was measured, about 2.8 was obtained at a measurement frequency of 1 kHz.
It has been confirmed that the dielectric constant can be made lower than the dielectric constant of about 3.2 in the case where the slot insulating portion is constituted only by the film. Further, the measurement of the leakage current was performed by applying a 60 Hz, 10 Hz to the field coil.
When an average current value leaking and flowing when the iron core is grounded is measured by applying 0 V and compared with a value using a normal PET film as 100, it is about 90.
It was confirmed that the leakage current was reduced by about%. (Example 2) P having a film thickness of 30 μm and a dielectric constant of 2.9
Five EN films, four ETFE films each having a film thickness of 20 μm and a dielectric constant of 2.6 are alternately sandwiched to form a multilayer, and a film having a total film thickness of 230 μm having a configuration of FIG. The stator was inserted into the slot insulation part of the magnetic coil to produce a motor stator. With this configuration, no extreme ETFE film breakage occurred during processing. In addition, this composite film, after the hydrophilic processing of the ETFE film surface by plasma treatment,
The interface of each multilayer was laminated at a temperature of 150 ° C. via an unsaturated polyester crosslinked adhesive layer capable of obtaining heat resistance of 120 ° C. or higher.

When the dielectric constant between the field coil and the iron core was measured, about 2.8 was obtained at a measurement frequency of 1 kHz.
It has been confirmed that the dielectric constant can be made lower than the dielectric constant of about 3.2 in the case where the slot insulating portion is constituted only by the film. Further, the measurement of the leakage current was performed by applying a 60 Hz, 10 Hz to the field coil.
0 V was applied, and the average current value that leaked and flowed when the iron core was grounded was measured.
When comparing the value using the film to 100, about 90
It was confirmed that the leakage current was reduced by about 10%. ( Reference Example ) A PTFE fine powder having an average particle size of 25 μm
After dispersing in PET so as to be 5 vol%, a PET film having a fluororesin having a film thickness of 250 μm was formed. In this film, the PTFE fine powder acts as a foam nucleus at the time of stretching, and the volume ratio of pores is about 10 vol%.
Is formed. Using this film, insert it into the core of the rotating machine and the slot insulation of the field coil,
An electric motor stator was fabricated. With this configuration, the film did not break during processing.

When the dielectric constant between the field coil and the iron core was measured, about 2.8 was obtained at a measurement frequency of 1 kHz.
It has been confirmed that the dielectric constant can be made lower than the dielectric constant of about 3.2 in the case where the slot insulating portion is constituted only by the film. Further, the measurement of the leakage current was performed by applying a 60 Hz, 10 Hz to the field coil.
When 0 V is applied and the iron core is grounded, the average current value which leaks and flows is measured, and compared with a value using a normal PET film of the same thickness as 100, it is about 90, and 10% It was confirmed that the leakage current was reduced to a certain extent.

[0041]

As is apparent from the above description,
The present invention has good economy, heat resistance, moldability,
To obtain a low dielectric constant of a slot insulating portion that cannot be obtained with a bulk polyester film by using a polyester film having a fluororesin obtained by compounding a polyester resin and a fluorinated resin for a slot insulating portion of a rotating machine. Thus, the leakage current of the AC component of the rotating machine can be effectively reduced while maintaining the insulation performance.

According to the present invention, it is possible to further improve the efficiency of the rotating machine in response to the increase in the frequency of electric and electronic equipment, and to contribute to downsizing and cost reduction. It is of great industrial value.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a configuration of a slot insulating portion in a rotating machine of the present invention.

FIG. 2 is an equivalent circuit of electric leakage in a slot insulating part in the rotating machine of the present invention.

FIG. 3 is a schematic diagram illustrating a configuration of a polyester film having a fluororesin used for a slot insulating portion of a rotating machine according to an embodiment of the present invention.

FIG. 4 is a schematic view illustrating a configuration of a polyester film having a fluororesin used for a slot insulating portion of a rotating machine according to another embodiment of the present invention.

FIG. 5 is a schematic diagram showing a configuration of a polyester film having a fluororesin used for a slot insulating portion of a rotating machine in a reference example .

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Iron core part 2 Field coil 3 Field coil covering insulation part 4 Slot insulation film insulation part 5 Polyester film 6 Fluorinated resin film 7 Polyester base film 8 Dispersion of fluorinated resin fine powder 9 Void

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-29937 (JP, A) JP-A-57-143521 (JP, A) JP-A-62-297348 (JP, A) JP-A-53-143 1900 (JP, A) Actually open 63-55322 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02K 3/30-3/52 H01F 27/32 C08J 5/00- 9/42

Claims (3)

(57) [Claims] 1. A core and slot insulating portion of the field coil, two polyester film of the fluorinated resin film
Rotating machine characterized by comprising consists of sandwiching the film by beam. 2. The rotating machine according to claim 1, wherein the film is multilayered with a fluorinated resin film such that the polyester film is the outermost surface. 3. A polyester film and a fluorine resin off
The rotating machine according to claim 2, wherein the rotating machine is laminated with a film .