JP7025224B2 - Rotating machine stator - Google Patents

Description

The present specification discloses a stator of a rotary electric machine having a stator core and a stator coil wound around the stator core.

As is well known, the stator of a rotary electric machine has a stator core and a stator coil. A plurality of teeth are provided on the stator core, and a stator coil is formed by winding a winding around the teeth. Then, a plurality of windings are lined up in the slot, which is a space between the teeth.

Here, the windings in the slot need to be insulated to prevent short circuits between the windings or between the windings and the stator core. Normally, the winding is covered with a coil film, but if the winding is not sufficiently fixed, the coil film may slide and wear due to an external force such as vibration.

Therefore, conventionally, it has been proposed to pour a varnish around the stator coil to fix the winding. However, in this case, if there is not a sufficient gap between the windings, the varnish does not enter between the windings, and the windings are not sufficiently fixed. In addition, fixing with varnish has caused problems that the material cost is high and the manufacturing process is complicated.

Patent Document 1 discloses a technique in which a foamed resin sheet is arranged between a plurality of windings and an inner wall of a slot, and the foamed resin sheet is heated and expanded to fix the windings. There is. According to such a technique, it is not necessary to pour the varnish, and the winding can be fixed relatively easily.

Japanese Unexamined Patent Publication No. 2011-244596

However, in the technique of Patent Document 1, a plurality of windings are housed in the slot in a state of being in contact with each other. In other words, in the case of Patent Document 1, there is no gap between the windings. Therefore, the foamed resin sheet cannot enter between the windings and only contacts the side surface of the windings. In this case, since the contact area between the winding and the foamed resin sheet is small, the fixing force of the winding is weak. In addition, there is a concern that the windings may slide with each other due to vibration or the like and wear.

Therefore, the present specification discloses a stator of a rotary electric machine in which the winding in the slot is more reliably fixed.

The stator of a rotary electric machine disclosed in the present specification includes a stator core including an annular yoke, a plurality of teeth protruding radially from the inner peripheral surface of the yoke, and a plurality of windings wound around the teeth. A stator coil composed of wires and a foamed resin sheet arranged along the inner wall of the slot, which is a space between the teeth, are provided, and the plurality of windings have a radial gap in the slot. A part of the foamed resin sheet is inserted into the gap between the windings, and the central portion of the windings in the slot facing the other windings in the circumferential direction. The gap resin is provided only in the coil, and the area of the gap resin is smaller than the area facing the other windings .

In such a configuration, since a part of the foamed resin sheet enters the gap between the windings, the contact area between the windings and the foamed resin increases, and the windings are more reliably fixed.

By providing the resin for the gap, the gap between the windings can be surely secured.

With such a configuration, it is possible to secure a space for the foamed resin sheet to enter between the windings.

Further, the gap resin may be a resin to which an insulating filler is added.

With such a configuration, it is possible to control the coating thickness of the gap resin and, by extension, the amount of gaps between windings to some extent.

According to the stator of the rotary electric machine disclosed in the present specification, since a part of the foamed resin sheet enters the gap between the windings, the contact area between the windings and the foamed resin increases, and the windings are more reliably performed. It is fixed.

It is a perspective view of a stator. It is an exploded perspective view of a stator. It is a front view of a segment coil. FIG. 3 is a cross-sectional view taken along the line AA of FIG. It is sectional drawing which shows the state in the slot before heating a foamed resin sheet. It is sectional drawing which shows the state in the slot after heating a foamed resin sheet. It is a flowchart which shows the flow of manufacturing of a stator. It is a figure which shows an example of another segment coil.

Hereinafter, the stator 10 of the rotary electric machine will be described with reference to the drawings. FIG. 1 is a perspective view of a stator 10 of a rotary electric machine. Further, FIG. 2 is an exploded perspective view of the stator 10. Note that FIG. 2 illustrates only a part of the segment coils 20.

The stator 10 is combined with a rotor to form a rotary electric machine. The rotary electric machine to which the stator 10 is applied may be one used as an electric motor or one used as a generator. Therefore, the stator 10 of this example is, for example, a rotary electric machine mounted on an electric vehicle, which functions as an electric motor for generating running power and also functions as a generator for generating power by regenerative torque or the like. May be applied to.

The stator 10 has a stator core 12 and a stator coil 14 wound around the stator core 12. The stator core 12 is roughly classified into a substantially annular yoke 15, and a plurality of teeth 16 projecting radially inward from the inner peripheral surface of the yoke 15. A slot 18 is formed between the teeth 16 adjacent to each other in the circumferential direction, which is a space in which a part of the stator coil 14 is accommodated. The stator core 12 may be, for example, a laminated steel plate formed by laminating a plurality of electromagnetic steel plates (for example, silicon steel plates) in the thickness direction. Further, the stator core 12 may be a dust core formed by press-molding magnetic particles coated with insulation.

The stator coil 14 is formed by winding a winding around a tooth 16. The connection mode and winding mode of the stator coil 14 may be appropriately selected according to the specifications of the rotary electric machine. Therefore, the stator coil 14 may have a configuration in which U-phase, V-phase, and W-phase coils are star-connected or delta-connected. Further, the stator coil 14 may be wound by distributed winding or by centralized winding. FIG. 1 shows a state in which a three-phase coil is distributed and wound.

Such a stator coil 14 is configured by connecting a plurality of segment coils 20. The segment coil 20 is a stator coil 14 cut to a length that is easy to handle, and is a winding that constitutes the stator coil 14. Hereinafter, the segment coil 20 is also appropriately referred to as a “winding 20”.

FIG. 3 is a front view of the segment coil (winding) 20. Further, FIG. 4 is a cross-sectional view taken along the line AA in FIG. The segment coil 20 is obtained by coating a conducting wire 24 made of a conductive material (for example, copper or the like) with a coil film 26 made of an insulating material. The conductor 24 is a flat conductor having a substantially rectangular cross section. The segment coil 20 is bent and molded into a substantially U shape before being assembled to the stator core 12. Hereinafter, the molding of the segment coil 20 before the core assembly is referred to as “primary molding”, and the molding by bending the segment coil 20 after the core assembly is referred to as “secondary molding”.

As shown in FIG. 3, the primary molded segment coil 20 has a pair of legs 28 inserted into the slot 18 and a connecting portion 30 connecting the pair of legs 28. The length of the leg portion 28 is longer than the axial dimension of the stator core 12, and when the leg portion 28 is inserted into the slot 18, a part of the leg portion 28 protrudes from the axial end surface of the stator core 12. This protruding portion is bent in the circumferential direction during secondary molding and is joined to another segment coil 20. Then, this protruding portion becomes a part of the coil end.

When the segment coil 20 is assembled to the core, the connecting portion 30 extends in the circumferential direction on the outer side in the axial direction of the stator core 12 to form a part of the coil end. At both ends of the segment coil 20, that is, at the ends of the legs 28, the coil film 26 is peeled off to form a peeled portion 31 in which the conducting wire 24 is exposed to the outside. The peeling portion 31 is welded to the peeling portion 31 of the other segment coil 20.

As shown in FIG. 2, the plurality of segment coils 20 are stacked in the radial direction and inserted into the corresponding slots 18. Therefore, in one slot 18, a plurality of segment coils 20, that is, a plurality of windings 20 are arranged in the radial direction. A foamed resin sheet 22 is arranged between the plurality of windings 20 and the inner wall of the slot 18. The foamed resin sheet 22 is in the form of a thin sheet in the initial state, but foams when heated and greatly expands. By arranging and expanding the foamed resin sheet 22 between the winding 20 and the inner wall of the slot 18, the gap between the winding 20 and the inner wall of the slot 18 is filled, and the winding 20 is formed in the slot 18. It is fixed.

In this example, in order to make the fixing of the winding 20 more reliable, the gap resin 32 is applied to the surface of the winding 20 facing the other winding 20 (the surface of the coil film 26). There is. In this example, since the windings 20 are laminated so that the coil thickness direction is the stator radial direction, the gap resin 32 is applied to one end surface of the windings 20 in the thickness direction.

The gap resin 32 is a resin applied to form a gap between the windings 20 laminated in the slot 18. The gap resin 32 is not particularly limited as long as it is a resin having an insulating property. However, in order to facilitate control of the coating thickness, it is desirable that the gap resin 32 is a resin to which an insulating filler 34 having a controlled particle size is added, as shown in FIG. In this case, it is desirable that the particle size of the insulating filler 34 is substantially the same as the gap thickness to be formed. When the gap resin 32 to which the insulating filler 34 is added is applied to the surface of the coil coating of the winding 20, even when the winding 20 is laminated in the thickness direction, insulation is provided between the windings 20. A gap having a size larger than the particle size of the filler 34 will be formed. As a result, the foamed resin sheet 22 enters between the adjacent windings 20, and the windings 20 are more firmly fixed in the slot 18.

This will be described in comparison with the prior art. Normally, the winding 20 constituting the stator coil 14 is covered with a coil film 26 in order to prevent a short circuit between the winding 20 or between the winding 20 and the stator core 12. However, if the winding 20 is not sufficiently fixed, the coil film 26 may slide and wear due to an external force such as vibration. Therefore, conventionally, there is a method of pouring a varnish around the stator coil 14 to fix the stator coil 14. However, when there is not a sufficient gap between the windings 20, the varnish does not enter between the windings 20, and the fixing is insufficient. Further, fixing with varnish has a problem that the material cost is high and the manufacturing process is complicated.

Therefore, it has been proposed in part that a foamed resin sheet 22 is arranged between the winding 20 and the inner wall of the slot 18 and the foamed resin sheet 22 is expanded to fix the winding 20. According to such a method, the winding 20 can be fixed more easily than the fixing by the varnish. However, conventionally, the gap resin 32 is not provided on the surface of the winding 20 facing the other winding 20, and the windings 20 are laminated in the slot 18 in a state of being in contact with each other. Was there. In other words, conventionally, there was no gap between the windings 20.

Therefore, even if the foamed resin sheet 22 is heated and expanded, the foamed resin sheet 22 only comes into contact with the side surface of the winding 20. Therefore, there remains a concern that the windings 20 come into contact with each other due to vibration or the like and are worn.

In this example, as described above, the gap resin 32 for forming a gap is applied to the surface of the winding 20 facing the other winding 20. Therefore, even if the windings 20 are laminated in the thickness direction, a gap corresponding to the coating thickness of the gap resin 32 is formed between the windings 20. Then, when the foamed resin sheet 22 is heated and expanded in a state where a gap exists between the windings 20, the foamed resin sheet 22 also enters the gap between the windings 20.

In FIG. 4, the gap resin 32 is applied only to one end surface of the winding 20 in the thickness direction. However, since it is sufficient that one or more gap resin 32s are provided between the two windings 20, the gap resin 32 may be applied to both sides of the windings 20 in the thickness direction. Further, among the plurality of windings 20 laminated in the radial direction, the odd-numbered surface (or even-numbered) windings 20 are coated with the gap resin 32 on both sides in the thickness direction, and the even-numbered (or even-numbered) windings 20 are coated. The winding 20 may be configured so that the gap resin 32 is not applied.

In any case, the gap resin 32 is interposed between the adjacent windings 20 in the slot 18, so that a predetermined gap is formed between the windings 20. As a result, the winding 20 is firmly fixed in the slot 18. 5 and 6 are schematic cross-sectional views showing the inside of the slot 18. FIG. 5 shows the state in the slot 18 before heating the foamed resin sheet 22, and FIG. 6 shows the state inside the slot 18 after heating the foamed resin sheet 22. Further, in FIGS. 5 and 6, the vertical direction of the paper surface is the radial direction of the stator, and the horizontal direction of the paper surface is the circumferential direction of the stator.

As shown in FIG. 5, and as described above, a plurality of (six in the illustrated example) windings 20 are arranged in the radial direction in the slot 18. A gap resin 32 is interposed between the windings 20, whereby a predetermined gap is formed between the windings 20. A foamed resin sheet 22 before foaming is arranged between the plurality of windings 20 and the inner wall of the slot 18. The foamed resin sheet 22 is folded in half so as to sandwich the plurality of windings 20. When the stator 10 is heated in this state, the foamed resin sheet 22 foams and expands. As a result, as shown in FIG. 6, the foamed resin sheet 22 is filled in the gap between the winding 20 and the inner wall of the slot 18 without any gap. Further, the foamed resin sheet 22 also enters the gap between the windings 20. As a result, the contact area between the winding 20 and the foamed resin sheet 22 increases, and the winding 20 is more firmly fixed. Further, even if the winding 20 moves due to vibration or the like, the gap resin 32 and the foamed resin sheet 22 are interposed between the windings 20, so that the windings 20 do not come into direct contact with each other and insulation can be maintained.

Next, the flow of manufacturing the stator 10 will be described with reference to FIG. 7. FIG. 7 is a flowchart showing a manufacturing flow of the stator 10. When manufacturing the stator 10, first, the stator core 12 is manufactured (S10). Since known prior art can be used for the procedure for manufacturing the stator core 12, detailed description here will be omitted. In parallel with the production of the stator core 12, the segment coil 20 is also manufactured (S11 to S16). When manufacturing the segment coil 20, first, a long coil material is cut to a desired length (S11). The coil material is a long material obtained by coating a long conductor 24 with a coil film 26. Subsequently, the coil film 26 is peeled from both ends of the segment coil 20 obtained by cutting to form the peeled portion 31 (S12). Next, the segment coil 20 is primarily formed, that is, bent into a substantially U shape (S14).

After the primary molding of the segment coil 20 is completed, the gap resin 32 is subsequently applied to a part of the segment coil 20 (S16). As described above, the gap resin 32 is applied to the surface of the segment coil 20 facing the other segment coil 20 in the slot, that is, the end surface in the thickness direction. As a result, the segment coil 20 is completed.

When the segment coil 20 is completed, the segment coil 20 is subsequently assembled to the stator core 12 (S18 to S26). Specifically, first, a plurality of segment coils 20 are laminated in the coil thickness direction, and the foamed resin sheet 22 before heating is wound around the laminated plurality of segment coils 20 (S18).

Then, a plurality of segment coils 20 around which the foamed resin sheet 22 is wound are inserted into the slot 18 (S20). The plurality of segment coils 20 inserted into the slot 18 are held so as not to fall out of the slot 18 by using a dedicated jig.

Subsequently, secondary molding is performed in which the protruding portion of the segment coil 20 projecting from the axial end surface of the stator core 12 is bent in the circumferential direction (S22). Then, the end portion (peeling portion 31) of the secondarily formed segment coil 20 is welded to the end portion (peeling portion 31) of the other segment coil 20 (S24).

When the welding of all the segment coils 20 is completed, finally, the stator 10 is heated to foam and expand the foamed resin sheet 22 (S26). As a result, the foamed resin sheet 22 is filled in the gap between the winding 20 and the inner wall of the slot 18 and the gap between the windings 20, and the winding 20 is fixed in the slot 18.

As is clear from the above description, the stator 10 disclosed in the present specification can be manufactured by the same procedure as before, although the step of applying the gap resin is newly added. Therefore, the stator 10 disclosed in the present specification can be manufactured without significantly changing the manufacturing procedure as compared with the conventional case. Then, according to the stator 10 disclosed in the present specification, the winding 20 is more firmly fixed in the slot 18 as compared with the prior art. As a result, the sliding of the winding 20 is reduced, and the wear of the coil film 26 caused by the winding 20 is prevented. Further, even if the winding 20 slides due to vibration or the like, the gap resin 32 and the foamed resin sheet 22 are interposed between the windings 20, so that the state where the insulation is secured can be maintained.

The configuration described so far is an example, and if there is a gap between the windings 20 in the slot 18 and the foamed resin sheet 22 is inserted in the gap, the other configurations are appropriately changed. You may. For example, in the example of FIG. 3, the gap resin 32 is applied over a relatively wide range. However, the range, shape, and number of the gap resin 32 may be appropriately changed as long as the gap between the windings 20 can be maintained. For example, as shown in FIG. 8, the gap resin 32 may be applied to a plurality of places at intervals in the coil axial direction. In this case, the coating range at one place may be small, and the shape may be circular or the like. However, in any case, the coating range of the gap resin 32 is larger than the facing surface of the winding 20 facing the other winding 20 in order to form a space for the foamed resin sheet 22 to enter. , Small is desirable.

Further, in the above description, the resin to which the insulating filler 34 is added is used as the gap resin 32, but a resin to which the filler 34 is not mixed may be used as long as the coating thickness can be controlled. In this case, the gap resin 32 may be a heat-softening resin that softens and flows down when the foamed resin sheet 22 is heated to foam. That is, in the completed stator 10, if there is a gap in which the foamed resin sheet 22 has entered between the windings 20, the gap resin 32 may not remain. Further, the gap resin 32 may be attached to the winding 20 by other means, for example, sticking with an adhesive, instead of coating. That is, a resin sheet (resin 32 for gaps) formed in advance to a predetermined thickness may be attached to the surface of the winding 20 by using an adhesive.

Further, in the description so far, one foamed resin sheet 22 is arranged in one slot 18, but a plurality of foamed resin sheets 22 may be arranged in one slot 18. For example, in one slot 18, two foamed resin sheets 22 arranged along the circumferential side surface of the slot 18 and one foamed resin sheet 22 arranged along the radial side surface of the slot 18. A total of three cards may be arranged.

Further, if the gap resin 32 is applied to the winding 20 before assembling the core, the manufacturing process shown in FIG. 7 may be appropriately changed. For example, the application of the gap resin 32 (S16) may be performed before the primary molding (S18) of the segment coil 20. Further, the foamed resin sheet 22 may be attached to the inner wall of the slot 18 in advance instead of being wound around the plurality of windings 20.

Further, in the description so far, the stator coil 14 is composed of a plurality of segment coils 20 joined to each other, but the stator coil 14 may be composed of continuous long windings 20.

10 stator, 12 stator core, 14 stator coil, 15 yoke, 16 teeth, 18 slots, 20 windings (segment coil), 22 foamed resin sheet, 24 leads, 26 coil coating, 28 legs, 30 connections, 31 peeling parts. , 32 Gap resin, 34 Insulation filler.

Claims (2)

A stator core comprising an annular yoke and a plurality of teeth radially protruding from the inner peripheral surface of the yoke.
A stator coil composed of a plurality of windings wound around the tooth, and a stator coil.
A foamed resin sheet arranged along the inner wall of the slot, which is a space between the teeth,
Equipped with
The plurality of windings are arranged in the slot with a radial gap.
A part of the foamed resin sheet has entered the gap between the windings, and is
Of the windings, the gap resin is provided only in the central portion in the circumferential direction of the surfaces facing the other windings in the slot.
The area of the gap resin is smaller than the area facing the other windings.
A stator of a rotary electric machine characterized by this. The stator of the rotary electric machine according to claim 1 .
The stator for a rotary electric machine is characterized in that the resin for gaps is a resin to which an insulating filler is added.

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