JP5190231B2 - Insulating sheet - Google Patents

Description

  The present invention relates to an insulating sheet used for a stator or rotor of a motor / generator, and more particularly to an insulating sheet inserted and disposed in a slot of a stator core core or rotor core.

Conventionally, devices such as a motor that generates rotational power using electric power and a generator that converts rotational power into electric power have been widely used in railways, electric vehicles, and the like. The motor and the generator use a common principle. Device. In a drive motor for a railway or an electric vehicle, the regenerative power is effectively used by causing the drive motor to act as a generator during braking.
Usually, a motor or a generator is provided with a fixedly arranged stator and a rotor provided rotatably with respect to the stator, and the stator and the rotor are formed by windings such as enamel wires. Coil is provided.
And in the motor, for example, by energizing the windings of the stator and generating a magnetic field in the coil, the magnetic field is used to generate a repulsive force between the permanent magnet and the rotor, Alternatively, the rotor winding is energized to generate a magnetic field with the coil, and a repulsive force is generated between the stator and the permanent magnet, thereby rotating the rotor.
Further, in the generator, an induced potential is generated in a coil provided in the stator by a change in a magnetic field generated by rotation of a rotor in which a permanent magnet is provided.

This coil is usually provided in a stator or rotor by arranging a winding in a groove called a slot formed in the stator core or rotor core.
The slots normally extend along a direction parallel to the rotation axis direction of the motor or generator, and a plurality of slots are formed on the surface of the stator core or the rotor core around the rotation axis at substantially equal intervals.
And the slot is formed in the length over the full length of a stator core or a rotor core, and the opening part is formed in the both end surfaces of a stator core or a rotor core.
For the formation of the stator core and the rotor core, a steel material having a high magnetic permeability is used from the viewpoint of the operation efficiency of the motor and the generator.
Therefore, for example, in order to prevent damage to the insulating film of the winding due to contact between the winding and the edge portion of the core end surface, the winding is surrounded by an insulating sheet such as a slot liner or a wedge. (Refer to Patent Document 1).
As the insulating sheets such as slot liners and wedges, mica sheets as described in Patent Document 1 or aramid paper are widely used.

  As described in Patent Document 2, this insulating sheet is usually disposed by being inserted into a slot from an opening on an end surface of a stator core or a rotor core. In particular, aramid paper is a general resin film. Compared to the above, it has a surface property that is excellent in sliding property, and is excellent in workability during insertion into the slot.

By the way, in recent years, motors and generators are required to be small and highly efficient, and an increase in the space factor of the winding is required.
Conventionally, mica sheets and aramid paper are more likely to have pinholes or the like due to thinning than resin films, and it is difficult to reduce the thickness while suppressing a decrease in insulation reliability.
Moreover, since aramid paper is less stiff than a resin film having the same thickness and tends to buckle, if it is made thin, it may cause buckling when inserted into a slot.
Furthermore, since aramid paper is only commercially available with a product of 50 μm or more, unlike a resin film, it is difficult to obtain a thin product of less than 50 μm.
For this reason, only a thick sheet having a laminated structure in which a plurality of mica sheets or aramid papers are laminated via an adhesive is used as an insulating sheet such as a conventional slot liner or wedge. In addition, the conventional insulating sheet usually has a thickness of about several hundred μm.
An insulation sheet having excellent slot insertion workability even when the space factor of the windings in the slot is high has not yet been found except for aramid paper, and suppresses the deterioration of slot insertion workability. However, it has been difficult to reduce the thickness of the insulating sheet.

  Therefore, it is difficult to expand the space for accommodating the winding in the slot, and it is difficult to satisfy the demand for an increase in the space factor of the motor or generator.

JP 2003-111328 A JP 2007-6777 A

  The subject of this invention is providing the insulating sheet thinned, suppressing the fall of the workability | operativity to insertion in a slot.

The inventors of the present invention focused on the surface properties of the insulating sheet and conducted intensive studies on the workability of insertion into the slot. As a result, the resin film having a predetermined surface roughness has slipperiness equivalent to that of aramid paper. As a result, the present invention has been completed.
That is, the present invention is an insulating sheet that is inserted and disposed in a slot of a stator core or a rotor core of a motor / generator to solve the above problems, and has an arithmetic average roughness (Ra) of 0.05 μm or more and 0.1 μm. A resin film having a surface roughness of 0.5 μm or more and 1.0 μm or less is used, and the surface having the surface roughness is defined as an inner wall surface of the slot. Provided is an insulating sheet in which the resin film is used in a state where the resin film is exposed on a surface in contact therewith.

  In this specification, the term “motor / generator” is any of “things that function only as motors”, “things that function only as generators”, and “things that function as both motors and generators”. It is used in the meaning including.

According to the present invention, the insulating sheet has an arithmetic average roughness (Ra) of 0.05 μm or more and 0.1 μm or less and a maximum height roughness (Rz) of 0.5 μm or more and 1.0 μm or less of the surface roughness. A film is used, and the resin film is used in a state where the surface having the surface roughness is exposed on the surface of the insulating sheet.
Therefore, the surface of the insulating sheet can be made to have the same slipperiness as a conventional insulating sheet using aramid paper.
In addition, by using a resin film, it is possible to reduce the thickness while suppressing the generation of pinholes compared to the case of using aramid paper.
Furthermore, by using a resin film, it is easier to impart stiffness to the insulating sheet than in the case of using aramid paper, and the buckling strength can be improved.
That is, it is possible to provide a thin insulating sheet while suppressing a decrease in workability of insertion into the slot.

  Hereinafter, preferred embodiments of the present invention will be described (based on the accompanying drawings).

  FIG. 1 is a schematic view showing an outline of a cross section when the induction motor is cut in a plane perpendicular to the rotation axis, and FIG. 2 is surrounded by a broken line indicated by a symbol “A” in FIG. It is the enlarged view to which the area | region was expanded.

Reference numeral 10 denotes a rotating shaft having an elongated cylindrical shape disposed at a substantially central portion of the induction motor.
Reference numeral 20 denotes a rotor core that is provided on the outer peripheral side of the rotary shaft 10, and the rotor core is a generally cylindrical shape in which a through-hole through which the rotary shaft 10 can be inserted passes from one end side to the other end side. It is formed into a shape.
The rotary shaft 10 and the rotor core 20 are fixedly integrated into the induction motor so as to be rotatable around the rotary shaft 10.

Reference numeral 30 denotes a stator core that is fixedly disposed in the induction motor. The stator core 30 is formed in a substantially cylindrical shape having an inner diameter slightly larger than the outer diameter of the cylindrical shape of the rotor core 20. In addition, the hollow region formed inside the cylindrical shape is fixed and disposed in the induction motor in a state where the hollow region extends along the direction in which the rotation shaft of the motor extends.
The stator core 30 is disposed in the induction motor in a state where a slight gap is formed between the cylindrical inner peripheral surface and the outer peripheral surface of the rotor core 20 so that the rotor core 20 is accommodated in the hollow region.

Reference numeral 31 denotes a plurality of slots formed on the inner peripheral surface side of the stator core 30, and the plurality of slots 31 extend substantially parallel to the extending direction of the rotary shaft 10, and Adjacent slots 31 are arranged substantially parallel to each other.
Further, on the inner peripheral surface side of the stator core 30, linear openings 31a having a length from the one end side to the other end side of the stator core 30 (the entire length of the data core 30) are substantially parallel to each other by the slot 31. A plurality are formed.
The slot 31 is formed so as to penetrate the stator core 30 in the length direction, and an opening having the same shape as the cross-sectional shape of the slot 31 is formed on one end surface and the other end surface of the stator core 30. Yes.
Further, the depth of the slot 30 from the inner peripheral surface of the stator core 30 toward the outer peripheral side is substantially the same in all the slots 31.

32 is a tooth formed in a state of projecting in the direction of the rotary shaft 10 by a plurality of slots 11 formed on the inner peripheral surface side of the stator core 30.
The teeth 32 have a wide portion 32a formed wider at the front end portion in the protruding direction than the other portions, and have a cross section with a plane perpendicular to the extending direction of the slot 30 (the extending direction of the rotating shaft 10). It has a shape that is substantially T-shaped.
The formation of the rotor core 20 and the stator core 30 is not particularly limited. For example, a laminated body in which electromagnetic steel plates are laminated in the axial direction of the rotary shaft 10 can be used.

  Reference numeral 40 denotes a winding that is housed in the slot 31 and is used for a coil that constitutes the stator together with the stator core 30.

51 is disposed in the stator in a state of being interposed between the winding 40 and the inner wall surface of the slot 31, and mainly in the slot 31 before the winding 40 is accommodated in the stator core 30. It is an insulating sheet (hereinafter also referred to as a “slot liner”) that is inserted and arranged, and the slot liner 51 has a cross section by a plane perpendicular to the extending direction of the slot 31 (the extending direction of the rotating shaft 10), They are arranged in a substantially U-shape opened toward the direction of the rotation axis 10.
The slot liner 51 is formed slightly longer than the length of the slot 31, and the edge portion of the opening of the slot 31 formed on one end surface and the other end surface of the stator core 30 and the winding 40 are formed. In order to prevent the winding 40 from being damaged by direct contact, the both ends thereof are arranged so as to protrude from the openings of the slots 31 formed on the end surface of the stator core 30.

Reference numeral 52 denotes an insulating sheet (hereinafter also referred to as “wedge 52”) that is used together with the slot liner 51 and is inserted into the slot 31 after the winding 40 is accommodated in the stator core 30.
The wedge 52 is disposed so as to cover the opening of the slot liner 51 in the direction of the rotation axis 10, and has a U-shaped cross section opposite to the U-shaped cross section of the slot liner 51. And the wedge 52 are disposed in the slot 31 with their U-shaped tips overlapped.
In the slot 31, the front end portion of the wedge 52 in the U-shaped cross-sectional shape is superimposed on the outer side of the front end portion of the slot liner 51 in the U-shaped cross-sectional shape.
That is, in the slot 31, the front end portion of the wedge 52 in the U-shape is sandwiched between the front end portion of the U-shape of the slot liner 51 and the inner wall surface of the slot 31.
The wedge 52 is also formed slightly longer than the length of the slot 31, and the winding 40 is surrounded by the slot liner 51 and the wedge 52 in the slot 31 and is disposed in the stator core 30.

Each of the slot liner 51 and the wedge 52 is formed of a single resin film, and the surface has an arithmetic average roughness (Ra) of 0.05 μm or more and 0.1 μm or less and a maximum height. Roughness (Rz) The surface roughness is 0.5 μm or more and 1.0 μm or less.
Conventional slot liners and wedges using aramid paper usually have a thickness of about 350 μm. Therefore, for such a conventional slot liner and wedge, the space factor of the winding can be improved if the resin film has a thickness of 330 μm or less, for example.
Moreover, as the said resin film, it is more preferable that it is 300 micrometers or less, and it is further more preferable that it is 200 micrometers or less.
Note that when the thickness of the insulating sheet is reduced, the buckling strength may decrease as the thickness is reduced. Therefore, as the resin film having such a small thickness, a resin film formed using a resin having a high bending elastic modulus is preferable.

In addition, the resin film having the surface roughness as described above is used because of the slip property between the inner wall surface of the slot 31 when the arithmetic average roughness (Ra) is a value outside the above range. This is because there is a possibility that the insulating sheet may be buckled or wrinkled, and the insertion workability may be lowered due to the occurrence of a catch when inserted into the slot 31.
In addition, if the maximum height roughness (Rz) exceeds 1.0 μm, tearing may occur at a portion having the maximum height roughness (Rz).
Note that the front and back surfaces of the resin film need not necessarily have the above-mentioned surface roughness, and if necessary, only the surface side where the insulating sheet such as the slot liner 51 and the wedge 52 contacts the inner wall surface of the slot 31 has the above-mentioned roughness. Thus, for example, one surface side has an arithmetic average roughness (Ra) of 0.05 μm or more and 0.1 μm or less, and a maximum height roughness (Rz) of 0.5 μm or more and 1.0 μm or less. It is also possible to use a resin film having a smooth surface.

  The arithmetic average roughness (Ra) and the maximum height roughness (Rz) are defined in JIS B601-2001. For example, a surface roughness measuring instrument (model name “SURCOM” manufactured by Tokyo Seimitsu Co., Ltd.). 1400D-3DF "), and can be measured under measurement conditions of a stylus tip radius R = 2 μm, an evaluation length of 10 mm, a reference length of 2 mm, a cutoff value of 0.8 mm, and a measurement speed of 3 mm / second. .

As a resin film used for insulating sheets such as the slot liner 51 and the wedge 52, the resin film has excellent heat resistance as well as insulation. For example, it is operated at a voltage exceeding 750V for direct current and 600V for alternating current. Polyimide resin film, polyetherimide resin film, polyetheretherketone resin film, polyetherimide resin film, polyphenylene sulfide resin film, and ultrahigh molecular weight polyethylene resin It is preferably one of the films.
Of these, polyimide resin films and ultrahigh molecular weight polyethylene resin films are particularly suitable.

Also, a two-layer resin film formed by laminating different resins such as using a polyimide resin on one side and using an ultra-high molecular weight polyethylene resin on the other side, or three or more layers A resin film having a laminated structure of can also be used for the insulating sheet.
For example, a surface layer / adhesive layer in which a polyethylene terephthalate or polyethylene naphthalate film is used as a central layer, and a surface layer is formed on both surfaces of the central layer using a polyimide resin film or an ultrahigh molecular weight polyethylene resin film via an adhesive layer. A laminated film having a five-layer structure of / center layer / adhesive layer / surface layer can also be used as an insulating sheet.
By adopting such a structure, the excellent buckling strength of polyethylene terephthalate or polyethylene naphthalate film is reflected in the insulation sheet, while the excellent moisture and heat resistance and voltage resistance characteristics of polyimide resin film and ultrahigh molecular weight polyethylene resin film are reflected. Can be reflected on the insulating sheet.

  In this specification, the term “ultra high molecular weight polyethylene” cannot measure the melt flow rate according to JIS K 7210 as described in JIS K 6936-1 and -2. , 190 ° C., 21.6 kg, and a polyethylene material that is less than 0.1 g / 10 min when a melt mass flow rate (MFR) is measured is intentionally used.

Such a slot liner 51 and wedge 52 formed of a resin film are inserted into the slot 31 along the extending direction of the slot 31 from the opening formed on one end surface of the stator core 30. An excellent sliding property between the inner wall surface and the inner sheet can be prevented from being caught and buckling of the insulating sheet or causing wrinkles to reduce the insertion workability.
Moreover, the space for accommodating the winding 40 in the slot 31 can be increased as compared with the conventional case.

This will be further described with reference to FIG. 3 which is a schematic cross-sectional view in the case where the conventional slot liner 51x and the conventional wedge 52x are provided.
The conventional slot liner 51x and wedge 52x are formed, for example, by bonding aramid paper on both sides of a polyester resin film via an adhesive, or by laminating a plurality of mica sheets. It is formed to a thickness of about 100 μm.
As described above, since the slot liner 51x and the wedge 52x are thick, it is conventionally difficult to arrange the coil on the stator core 30 in a state where the accommodation space of the winding 40 in the slot 31 is compressed and the space factor is high. there were.
Further, the conventional slot liner 51x having such a laminated structure is stronger than necessary, and is particularly rigid when a mica sheet or the like is used.
Therefore, it is difficult to arrange along the inner surface shape of the slot 31, and, for example, at a portion where the inner wall of the slot 31 is bent, such as the corner C, between the inner wall surface of the slot 31 and the slot liner 51x. The gap A is likely to be generated, and the gap becomes a dead space, making it difficult to effectively use the accommodation space of the slot 31 for accommodating the winding 40.

  On the other hand, in the insulating sheets such as the slot liner 51 and the wedge 52 according to the present invention, a gap is hardly generated even in the corner portion of the slot 31, and the accommodation space of the slot 31 is sufficiently effective for accommodating the winding 40. Not only can the slot liner 51 and the wedge 52 itself be 50 μm or less in thickness, the winding 40 in the slot 31 can be compared to the case where the conventional slot liner 51x and the wedge 52x are used. The accommodation space can be increased, and the coil can be disposed on the stator core 30 with a high space factor.

In the present embodiment, the insulating sheet has been described taking the slot liner and the wedge inserted into the slot provided in the stator core of the induction motor as an example, but the use of the insulating sheet according to the present invention. Is not limited to the above case.
In the present embodiment, the slot liner and the wedge have been described as examples in that the characteristics such as the slip property can be particularly reflected in the insertion workability, but the present invention does not limit the insulating sheet to these, In general, it is intended to be inserted into the stator core and disposed on the stator core.

In the present embodiment, the insulating sheet has been described by way of example in which the insulating sheet is disposed on the stator core. However, the present invention is not limited to the insulating sheet disposed on the stator core, and is disposed on the rotor core. It may be a thing.
Further, in the present embodiment, the insulating sheet has been described by way of example in the case where it is disposed in the stator core of the motor, but the insulating sheet according to the present invention is not limited to the stator or rotor of the motor, The present invention can also be used for the stator and rotor of a generator, or the stator and rotor of a device that functions as both a motor and a generator.

  EXAMPLES Next, although an Example is given and this invention is demonstrated in more detail, this invention is not limited to these.

Example 1
(Insulating sheet)
(Resin film)
For the insulating sheet of Example 1, a resin film having the following laminated structure was used.
Structure: Total thickness 330 μm of five-layer structure of polyimide resin layer (25 μm) / adhesive layer (15 μm) / polyethylene naphthalate resin layer (250 μm) / adhesive layer (15 μm) / polyimide resin layer (25 μm)
Surface roughness (surface roughness of polyimide resin layer): arithmetic average roughness (Ra) = 0.07 μm, maximum height roughness (Rz) = 0.78 μm
In addition, this surface roughness is based on JIS B601-2001, using a surface roughness measuring instrument (model name “SURCOM 1400D-3DF”) manufactured by Tokyo Seimitsu Co., Ltd., stylus tip radius R = 2 μm, It is measured under measurement conditions of an evaluation length of 10 mm, a reference length of 2 mm, a cutoff value of 0.8 mm, and a measurement speed of 3 mm / second.

(Wedge molding)
After the resin film was cut into an arrow feather shape having a width of 9 mm as shown in FIG. 4, both ends in the width direction were bent 90 degrees in the same direction along the broken line in the figure to produce a wedge with a U-shaped cross section. .

(Evaluation)
(Insertion workability)
Using a wedge insertion machine, the insertion workability into the slot was evaluated.
Regarding workability, a conventional wedge (conventional example) shown later is used as a reference, and it is determined as “◯” when it is equivalent to the conventional example.
Further, the case where buckling or the like was less likely to occur than in the conventional wedge and the insertion was smooth could be determined as “◎”.
Furthermore, the case where buckling or catching is likely to occur and a more careful work than the conventional wedge is required was determined as “x”.

(Measurement of buckling strength)
In addition, the buckling strength was measured.
The measurement was performed as follows.
First, two samples having a width of 57 mm and a length of 62 mm were prepared, and both of the two samples were bent at a right angle at the center in the length direction.
The folded samples are made to face each other, and the ends of the samples are brought together to form a square tube (31 mm square × 57 mm long) sample. The lower end of the square tube sample is a square with an inner size of 31 mm square. Mounted on bottomed formwork.
Furthermore, the same type mold is mounted on the upper end side of the square cylindrical sample, the distance between the upper and lower molds is reduced at a speed of 5 mm / min, and the maximum stress value observed before the molds come into contact with each other is calculated. The buckling strength was measured (see FIG. 5).
The results are shown in Table 1.

(Comparative Example 1)
A wedge was prepared in the same manner as in Example 1 except that a polyimide resin layer having a maximum height roughness (Rz) = 0.3 μm was formed, and evaluation was performed in the same manner as in Example 1.
The results are shown in Table 1.

(Conventional example)
Aramid paper (trade name “NOMEX paper”: 50 μm) / adhesive layer (21 μm) / polyethylene naphthalate resin layer (188 μm) / adhesive layer (21 μm) / aramid paper (trade name “NOMEX paper”: 50 μm) Except for using a conventionally widely used insulating sheet having a total thickness of 340 μm, a wedge was produced in the same manner as in Example 1 and evaluation of this conventional example was performed in the same manner as in Example 1.
The results are shown in Table 1.

(Comparative Example 2)
As Comparative Example 2, a wedge was prepared in the same manner as in Example 1 using a single sheet of aramid paper (trade name “Nomex Paper”) having a thickness of about 250 μm as an insulating sheet, and evaluation was performed in the same manner as in Example 1.
The results are shown in Table 1.

(Comparative Example 3)
As Comparative Example 3, wedges were produced in the same manner as in Example 1 using a single sheet of aramid paper (trade name “Nomex Paper”) having a thickness of about 370 μm as an insulating sheet, and evaluation was performed in the same manner as in Example 1.
The results are shown in Table 1.

  Also from Table 1, according to the present invention, it is possible to suppress the workability of insertion into the slot from being lowered as compared with the conventional insulating sheet using aramid paper or the like, and to be thinner than the conventional insulating sheet. It can be seen that an insulating sheet that can be made simple can be provided.

Schematic which showed the cross section of the induction motor. The enlarged view to which the area | region shown with the symbol "A" of FIG. 1 was expanded. The enlarged view which showed the case where the conventional insulating sheet was used. Explanatory drawing (top view) of a wedge sample. Explanatory drawing which shows the buckling strength measuring method.

Explanation of symbols

  10: Rotating shaft, 20: Rotor core, 30: Stator core, 31: Slot, 32: Teeth, 32a: Wide part, 40: Winding, 51, 51x: Slot liner, 52, 52x: Wedge, A: Clearance, C: Corner

Claims (4)

An insulating sheet inserted and disposed in a slot of a stator core or rotor core of a motor / generator,
A resin film having an arithmetic average roughness (Ra) of 0.05 μm or more and 0.1 μm or less and a maximum height roughness (Rz) of 0.5 μm or more and 1.0 μm or less is used, The insulating sheet, wherein the resin film is used in a state where a surface having the surface roughness is exposed on a surface in contact with an inner wall surface of the slot .   The insulating sheet according to claim 1, wherein the resin film is any one of a polyimide resin film, a polyether ether ketone resin film, a polyetherimide resin film, a polyphenylene sulfide resin film, and an ultrahigh molecular weight polyethylene resin film.   The insulating sheet according to claim 1 or 2, which is a slot liner.   The insulating sheet according to claim 1, which is a wedge.

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