JP5848579B2 - Segment coil, segment coil manufacturing method, and stator - Google Patents

Description

  The present invention relates to a segment coil, a method for manufacturing a segment coil, and a stator. Specifically, the present invention relates to a segment coil that can prevent partial discharge between adjacent coils.

  For example, a stator constituting an electric motor is configured by providing a coil on an annular core. The annular core is provided with a plurality of slots that open to the inside at predetermined intervals, and the coils are mounted in the slots. Conventional coils are provided by winding a bendable wire around the slot. However, there is a problem that it is difficult to wind the winding wire around the slot that opens to the inside without damaging, and workability is poor.

  Further, in a winding that can be bent, a large current cannot be flowed because the diameter cannot be set large. For this reason, it is difficult to increase the output of the electric motor. Further, in order to meet the demand for improvement in output and miniaturization of the motor, it is necessary to increase the space factor of the coil. However, it is difficult to improve the space factor in the configuration in which the winding is wound.

  In order to solve the above-described problem, a plurality of segment coils that are formed in advance in a form that allows a coil material having a large cross-sectional area to be mounted in the slot are mounted in the slot, and a connection end extending from the slot is welded or the like Thus, it is possible to adopt a method of connecting and configuring the coil. Since the cross-sectional area can be set large by making the cross-section of the segment coil correspond to the cross-sectional shape of the slot, a large current can flow and the space factor can be set large, and the output of the motor Can be increased.

Japanese Patent No. 4688003

  The segment coil is provided with an insulating coating layer for performing insulation between the adjacent segment coil and the core. The insulating coating layer needs to be configured so that partial discharge does not occur between the members. The partial discharge is likely to occur in a portion where the voltage difference is large. For example, when a segment coil is employed in the stator of a three-phase AC motor, the voltage difference between the segment coils belonging to different phases is the largest. Therefore, partial discharge is likely to occur at a portion where segment coils belonging to different phases are close to or in contact with each other.

  On the other hand, the voltage difference between segment coils belonging to the same phase or between the core and segment coils is smaller than the voltage difference between segment coils belonging to the same phase.

  Conventional segment coils are configured to prevent partial discharge by providing an insulating coating layer that can cope with a voltage difference between segment coils belonging to different phases over the entire area of the segment coil.

  However, it is not necessary to provide a thick insulating coating layer that can cope with a large voltage difference at a portion where the segment coils belonging to the same layer are in contact or a portion where the core and the segment coil are in contact. However, in the conventional segment coil, since the insulation coating layer that can cope with the voltage difference between the coils belonging to different phases is provided over the entire area of the coil, the space factor in the slot is lowered and the motor is increased in size. Or lead to an increase in the amount of heat generated.

  In order to increase the space factor, it may be possible to form an insulating coating layer with a small thickness on the entire segment coil using an expensive insulating material with a low relative dielectric constant and high insulation performance, but this increases the manufacturing cost. Will be connected.

  The invention of the present application solves the above-mentioned conventional problems, can set a large cross-sectional area of the coil to allow a large current to flow and prevent partial discharge, and improve the motor performance by increasing the space factor. An object is to provide a segment coil that can be used.

  The invention described in claim 1 of the present application is a segment coil mounted in a slot provided in a stator core, and includes a voltage difference between adjacent segment coils, and a segment coil and a core in contact with the segment coil. Insulating coating layers having different thicknesses are provided according to the voltage difference between them.

  For example, in a three-phase AC motor, the voltage difference between segment coils belonging to different phases is the largest. On the other hand, the voltage difference between the core and the segment coil is smaller than the voltage difference between the segment coils belonging to different phases, and the voltage difference between the segment coils belonging to the same phase is smaller than the voltage difference between the core and the segment coils. It becomes even smaller.

  Therefore, by changing the thickness of the insulating coating layer according to the voltage difference between adjacent coils or cores, partial discharge can be efficiently prevented without reducing reliability. In addition, since the average thickness of the insulating coating layer can be reduced, the weight can be reduced. In addition, the manufacturing cost can be reduced.

  The thickness of the insulating coating layer is not particularly limited as long as it is formed to a thickness that can prevent partial discharge based on a voltage difference and a positional relationship with adjacent members. For example, when segment coils belonging to different layers are brought into contact with each other at the coil end portion, the thickness of the insulating coating layer at least at the contact portion is set large. On the other hand, the thickness of the insulating coating layer at the portion that contacts the core in the slot can be set smaller than the portion where the segment coils belonging to different phases come into contact. Furthermore, the thickness of the insulating coating layer in the portion where the segment coils belonging to the same phase are brought into contact can be set smaller. Further, when there is a gap between adjacent segment coils, the thickness of the insulating coating layer can be set small.

  The segment coils belonging to different phases are likely to come close to or come into contact with each other at the coil end portion where the segment coil extends from the slot. Therefore, as in the invention described in claim 2, the thickness of the insulating coating layer in the portion accommodated in the slot is set smaller than the thickness of the insulating coating layer provided in the coil end portion extending from the slot. Is preferred.

  If the thickness of the insulating coating layer in the portion accommodated in the slot of the segment coil is set smaller than the conventional one, the segment coil can be formed from a coil material having a larger cross-sectional area. For this reason, it becomes possible to raise the space factor in the said slot, and can raise the efficiency of an electric motor.

  On the other hand, the segment coil is bent at the coil end. When bending a segment coil provided with an insulating coating layer, if the thickness of the insulating coating layer is large, a crack or the like may occur in the bent portion, which may reduce the insulation. For this reason, as in the invention described in claim 3, it is preferable to set the thickness of the insulating coating layer of the portion to be bent in the coil end portion to be small. Note that this is not the case when the insulating coating layer is provided after bending.

  When a rectangular wire having a rectangular cross section is adopted as the coil material, the core is brought into contact with the side surface in the circumferential direction of the segment coil in the portion accommodated in the slot, while the segment belonging to the same layer on the side surface in the radial direction The coil is brought into contact.

As described above, the voltage difference between the segment coils belonging to the same phase is smaller than the voltage difference between the segment coil and the core. Therefore, when the segment coil is formed of a rectangular wire having a rectangular cross section as in the first aspect of the invention, the thickness of the insulating coating layer at the portion in contact with the adjacent segment coil is set in the slot. The thickness can be set smaller than the thickness of the insulating coating layer in the portion in contact with the inner surface of the slot.

  By adopting the above configuration, it becomes possible to optimize the thickness of the insulating coating layer of the segment coil in the slot according to the voltage difference with the member to be contacted, and further increase the space factor in the slot. Is possible.

The configuration of the insulating coating layers having different thicknesses is not particularly limited. In a single process, insulating coating layers having different thicknesses can be formed using the same coating material. In addition, as in the first aspect of the invention, the first insulating coating layer formed almost over the entire area of the segment coil , and each segment coil is laminated at a predetermined portion of the first insulating coating layer. By providing the second insulating coating layer, the thickness of the insulating coating layer can be varied depending on the portion. Note that the second insulating coating layer is not limited to one layer, and may be configured to include two or more layers as necessary.

  The method for forming the first insulating coating layer and the second insulating coating layer is not particularly limited. For example, the insulating coating layer can be formed by powder coating or electrodeposition coating.

  As the first insulating coating layer, it is preferable to provide an insulating coating layer that can be bent. Thereby, it can bend in the state provided with the 1st insulating coating layer, and a 2nd insulating coating layer can be provided in the part where a voltage difference with an adjacent segment coil etc. becomes large after that. Thereby, insulating coating layers having different thicknesses can be easily formed.

As in the invention described in claim 4 , the materials constituting the first insulating coating layer and the second insulating coating layer are made different from each other, and the first insulating coating layer has a breaking elongation of 40% or more. On the other hand, a material having an elongation at break of less than 40% can be used for the second insulating coating layer.

  An insulating coating material having an elongation at break of less than 40% is inexpensive but difficult to bend. On the other hand, an insulating coating material having an elongation at break of 40% or more is expensive but has high workability.

For this reason, for example, the number of manufacturing steps can be reduced by bending a coil material having the first insulating coating layer with a small thickness as a whole, using an expensive material with a high breaking elongation. it can. On the other hand, after the bending process, in the portion where the voltage difference with the adjacent coil becomes large, the insulation is ensured by providing the second insulating coating layer having a required thickness with a material having a small breaking elongation but low cost. In addition, the manufacturing cost can be reduced.

The invention described in claim 5 is the method of manufacturing a segment coil according to any one of claims 1 to 4 , wherein the coil material in which the insulating coating layer is not formed, or the first insulating coating. A step of preparing a coil material provided with a layer, a step of bending the coil material into a predetermined shape, and an additional insulating coating layer for providing a second insulating coating layer on a predetermined portion of the bent segment coil Forming process.

  By adopting the above manufacturing method, it becomes possible to form an insulating coating layer having a thickness corresponding to the voltage difference between adjacent members of the segment coil, and it is possible to efficiently prevent partial discharge in each part. .

  The additional insulating coating layer forming step can be performed so as to form a plurality of insulating coating layers. For example, when a coil material not formed with an insulating coating layer is employed, first, a required shape is bent, and in the additional insulating coating layer forming step, the coating layer corresponding to the first coating layer is coiled. Then, a second coating layer that can cope with a voltage difference between coils belonging to different phases can be formed on a required portion. When this configuration is adopted, since the insulating coating layer corresponding to the first insulating coating layer is not exposed to bending, an insulating coating layer corresponding to the first insulating coating layer can be formed using an inexpensive insulating material. it can.

A sixth aspect of the present invention is a method for manufacturing a stator including the segment coil according to any one of the first to fourth aspects, wherein the segment coil is assembled to a predetermined portion of the core. And a connecting step of connecting predetermined connecting ends of each segment coil, and a connecting end insulating coating layer forming step of providing an insulating coating layer on the connecting ends connected in the connecting step.

  The method for performing the connection end insulating coating layer forming step is not particularly limited. For example, the insulating coating layer can be formed by dipping the connection end portion into a molten resin.

The segment coil according to the present invention can be applied to a stator employed in various electric motors and generators as in the invention described in claim 7 .

  Insulation between the segment coils and between the segment coils and the core can be ensured, and the space factor can be increased and the efficiency of the motor can be increased.

It is a perspective view of the principal part which shows the state which assembled | attached the segment coil to the core. It is a front view which shows an example of a segment coil. It is principal part sectional drawing of the segment coil which concerns on this invention. It is principal part sectional drawing of the segment coil which concerns on 2nd Embodiment. It is principal part sectional drawing orthogonal to the axis | shaft of the core which mounted | wore with the segment coil.

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

  FIG. 1 is a perspective view of a main part showing a state in which the segment coil 1 is mounted on the core. FIG. 2 is a front view showing one embodiment of the segment coil.

  The core 2 has a thick annular structure made of a magnetic material, and slots 3 are formed at predetermined intervals in the inner peripheral portion so as to penetrate in the axial direction and open to the inner peripheral surface. The slot 3 is formed substantially corresponding to the width of the segment coil 1, and the segment coil 1 is assembled to the core 2 by accommodating the straight portion of the segment coil in the slot.

  The material which comprises the said core 2 is not specifically limited. For example, a core formed by compacting magnetic powder or a core formed by stacking magnetic steel plates can be employed.

  For example, in a three-phase induction motor, a plurality of segment coils each grouped into a U phase, a V phase, and a W phase are assembled at predetermined intervals in the slot.

  As shown in FIG. 2, the segment coil 1 includes a pair of linear portions 1b accommodated in the slot 3, and a pair of coil end portions 1a that extend from both axial ends of the slot and have a chevron shape. , 1c and a substantially hexagonal shape. One of the coil end portions 1a is provided so as to connect a pair of straight portions 1b accommodated in a predetermined slot in a spanning manner. The other coil end portion 1c is provided with connection portions 4a and 4b for connection with segment coils accommodated in other slots. A plurality of segment coils constituting each phase are connected via the connection parts 4a and 4b. A plurality of forms of the other coil end portion 1c are prepared according to the connection pattern of the segment coils.

  The segment coil 1 is formed with an insulating coating layer 5 over the entire outer periphery excluding the connecting portions 4a and 4b, and is configured to ensure insulation between adjacent segment coils and cores. .

  FIG. 3 shows a cross section of the segment coil 1 according to the first embodiment of the present invention.

  As shown in FIG. 3, the segment coil 1 is configured by providing an insulating coating layer 5 on the outer peripheral surface of a conductive flat coil material 6 having a rectangular cross section.

  The insulating coating layer 5 is laminated on the outer periphery of the first insulating coating layer 5a in the first insulating coating layer 5a formed over the entire outer peripheral surface of the coil material 6 and the coil end portions 1a and 1c. And the second insulating coating layer 5b.

  The first insulating coating layer 5 a is formed with a thickness of 5 to 25 μm and a uniform thickness over the entire outer periphery of the coil material 6 using a material that can withstand bending such as polyimide. The first insulating coating layer 5a is formed after the coil material is drawn. The coil material including the first insulating coating layer 5a is bent to form a coil form as shown in FIG.

The second insulating coating layer 5b is provided by being laminated on the first insulating coating layer 5a of the coil material 6 subjected to the bending process. The second insulating coating layer 5b is formed with a thickness of 80 to 120 [mu] m according to the voltage difference between adjacent segment coils and the voltage difference between the segment coils and the core in contact therewith. The thickness of the insulating coating layer can be obtained from the following Darkin's rule of thumb.
V = 163 × (2t ÷ εr) ^0.46
V: Partial discharge start voltage (V)
t: Thickness (μm) of insulation coating layer on one side of winding
εr: relative dielectric constant For example, when a plurality of insulating coating layers are provided, each insulating coating layer is regarded as a series equivalent circuit of capacitors, and the capacitor capacity and dielectric constant of the entire insulating coating layer are obtained. The thickness of the insulating coating layer can be estimated using the law.

  As shown in FIG. 3, in the segment coil according to the present embodiment, only the first insulating coating layer 5 a is formed in the portion accommodated in the slot 3 of the core 2. For this reason, it becomes possible to set large the cross-sectional area of the coil material 6 of the part accommodated in the said slot 3, a space factor can be raised and the output of an electric motor can be improved.

  On the other hand, in addition to the first insulating coating layer 5a, a second insulating coating layer 5b is formed on the coil end portion 1a of FIG. For this reason, as shown in FIG. 1, even if adjacent segment coils are arranged in contact, it is possible to ensure insulation. In particular, the second insulating coating layer 5b according to the present embodiment is formed so that partial discharge does not occur even when segment coils belonging to different phases come into contact or close to each other. For this reason, a highly reliable stator can be constituted.

  In the present embodiment, the second insulating coating layer 5 b is not provided on the bent portions 7 and 8 of the segment coil 1. By adopting this configuration, even when bending is performed after the second insulating coating layer 5b is provided, the second insulating coating layer 5b is not cracked, and exhibits high insulation. Is possible.

  After assembling the segment coils belonging to all phases to the slot 3, the segment coils constituting each phase are welded and connected via the connection portions 4a and 4b in the coil end portion 1c. Thereafter, a connection end insulating coating layer (not shown) is provided on the connection portions 4a and 4b. There are no particular limitations on the material and method of forming the connection end insulating coating layer. For example, the connection end portions 4a and 4b can be formed by dipping the above-described polyamideimide resin.

  In the first embodiment shown in FIG. 3, the second insulating coating layer 5b is provided in almost the entire region of the coil end portion 1a. However, the portion where the second insulating coating layer is provided is between the adjacent members. It can be set according to the voltage difference.

  In the second embodiment shown in FIG. 4, the first insulating coating layers 15a and 25a are provided in almost the entire region of the segment coils 11 and 21 belonging to different phases, and only in the vicinity of the contact portion between the segment coils 11 and 22. Second insulating coating layers 15b and 25b are provided. By adopting this configuration, it is possible to effectively prevent partial discharge between segment coils belonging to different phases, reduce the insulating material for forming the second insulating coating layer, and further increase the manufacturing cost and the weight of the motor. Can be reduced.

  FIG. 5 shows a third embodiment of the present invention.

  As shown in FIG. 5, the straight portions 31 b and 41 b of the plurality of segment coils 31 and 41 are accommodated in the radial direction of the core 32 in a slot 33 provided in the core 32. The segment coils 31 and 41 are segment coils belonging to the same phase in the three-phase induction motor.

  As is clear from FIG. 5, each segment coil 31 is in contact with the segment coils 31, 41 having the same phase in the radial direction of the core, except for the segment coil 41 arranged at the innermost part. The circumferential surfaces of 31 and 41 are in contact with the inner surface of the slot 33.

  The voltage difference between the segment coils belonging to the same phase is smaller than the voltage difference between the core and the segment coil. For this reason, in this embodiment, the insulation coating layer 35 according to the voltage difference with the member which contacts is provided.

  Specifically, a first coating layer 35a is provided at a portion where the segment coils belonging to the same phase are in contact with each other, and a portion which is in contact with the inner surface of the slot 33 is provided with the first insulating coating. In addition to the layer 35a, a second insulating coating layer 35b is formed. In addition, since the material which comprises the 1st insulating coating layer 35a and the 2nd insulating coating layer 35b is the same as that of 1st Embodiment, description is abbreviate | omitted.

  In the present embodiment, the first insulating coating layer 35 is formed with a thickness of 5 to 25 μm, as in the first embodiment, while the second insulating coating layer 35 b is 80 to 120 μm thick. It is formed with.

  Note that the second insulating coating layer 35 b is formed on the circumferential surface that is in contact with the inner surface of the slot 33 in the segment coils 31 other than the segment coil 41 accommodated in the innermost portion. On the other hand, in the segment coil 41 accommodated in the innermost part, the second insulating coating layer 35 b is formed on the surface that contacts the bottom surface and the side surface of the slot 33.

  By adopting the above configuration, the thickness of the insulating coating layer 35 in the slot 33 can be optimized, and it is not necessary to provide an excessively thick insulating coating layer. For this reason, the cross-sectional area of the segment coils 31 and 41 can be set large, and a space factor can be raised.

  The scope of the present invention is not limited to the embodiment described above. The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined not by the above-mentioned meaning but by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

  By optimizing the thickness of the insulation coating layer provided on the segment coil, the space factor of the coil can be increased, and the efficiency of the electric motor can be improved.

1 segment coil 2 core 3 slot 5 insulation coating layer

Claims (7)

A segment coil mounted in a slot provided in a stator core,
Depending on the voltage difference between the adjacent segment coils and the voltage difference between the segment coil and the core in contact with the segment coil, an insulating coating layer having a different thickness is provided ,
The segment coil is formed of a rectangular wire having a rectangular cross section, and in the slot, the thickness of the insulating coating layer in the portion that contacts the adjacent coil is more than the thickness of the insulating coating layer in the portion that contacts the slot inner surface. Set smaller,
A first insulating coating layer formed over substantially the entire outer peripheral surface of the segment coil;
A segment coil in which the thickness of the insulating coating layer is made different by providing each segment coil with a second insulating coating layer formed in a predetermined position on the first insulating coating layer .   The segment coil according to claim 1, wherein a thickness of a portion of the insulating coating layer accommodated in the slot is set to be smaller than a thickness of an insulating coating layer provided at a coil end portion extending from the slot.   The segment coil according to claim 2, wherein a thickness of an insulating coating layer in a portion to be bent is set small in the coil end portion. While differentiating the materials constituting the first insulating coating layer and the second insulating coating layer,
While adopting a material having a breaking elongation of 40% or more for the first insulating coating layer,
The segment coil according to any one of claims 1 to 3 , wherein a material having a breaking elongation of 40% or less is used for the second insulating coating layer. It is a manufacturing method of the segment coil according to any one of claims 1 to 4 ,
Preparing a coil material without an insulating coating layer, or a coil material provided with a first insulating coating layer;
A processing step of bending the coil material into a predetermined shape;
And an additional insulation coating layer forming step of providing an insulation coating layer on a predetermined portion of the coil that has been bent. It is a manufacturing method of a stator provided with the segment coil described in any one of claims 1 to 4 ,
A segment coil assembling step for assembling the segment coil to a predetermined portion of the core;
A connection step of connecting between predetermined connection ends of each segment coil;
And a connecting end insulating coating layer forming step of providing an insulating coating layer at the connecting end connected in the connecting step. A stator comprising the segment coil according to any one of claims 1 to 4 .

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