JP2014027851A - Method of fixing coil to tooth, and stator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of fixing a coil to teeth, and a stator that can tightly fix the teeth and coil without using varnish nor causing the coil to shift from the teeth along the axis of a stator core.SOLUTION: There is provided a method of fixing a coil 50 around teeth 12 of a stator core 10 which has the plurality of teeth 12 projected radially inward from an annular yoke 11 and also has slots 13 formed between the teeth 12, 12, the method including the steps of: taking measures to prevent the coil 50 from shifting along the axis of the stator core 10 on end faces of the teeth 12 on a coil end side (arranging spacers 20, 30); arranging a cylindrical heat expandable sheet 30 around the teeth 12; forming the coil 50 at a periphery of the heat expandable sheet 40; and fixing the coil 50 around the teeth 12 by heating at least the heat expandable sheet 40.

Description

  The present invention relates to a method of arranging and fixing a coil around teeth of a stator core and a stator.

  A stator that constitutes a motor (electric motor) includes a steel plate laminate or a dust core including an annular yoke, a plurality of teeth projecting radially inward from the yoke, and a slot formed between adjacent teeth. It is generally composed of a stator core and a coil formed around the teeth.

  By the way, in recent motors with a high space factor, there is an urgent need for a method that can firmly fix both the stator core (especially teeth) and the coil, which are constituent elements, without applying a varnish. Yes.

  For example, when forming a coil through an insulator such as insulating paper around a tooth, a gap is likely to be formed between the end surface on the coil end side of the tooth and the coil. In the conventional fixing method, this gap is impregnated with varnish. The gap could be closed by being fixed. However, if the impregnation of the varnish is abolished and the gap remains unoccluded, the coil is in the axial direction of the stator core (the axial direction of the rotating shaft attached to the rotor core to be disposed in the center of the stator core). The stator core and the coil cannot be firmly fixed.

  Here, in patent document 1, after inserting the rectangular sheet | seat in which the surface was comprised with the foamed resin in the slot between teeth in the state bent in the center part, a coil is formed in teeth and a sheet is heated and expanded. Accordingly, a method is disclosed in which a foamed resin portion is formed between the stator core and the coil and both are fixed. According to this method, it is possible to fix the stator core and the coil without impregnating the varnish between the conductive wires constituting the coil.

  However, in the fixing method disclosed in Patent Document 1, it is clear that the tooth and the coil are fixed via the seat on the slot wall surface, but there is a gap that may be generated between the coil end side end surface of the tooth and the coil. Since there is no mention of blockage, whether or not the above-described problem, that is, the problem that the coil is likely to be displaced in the axial direction of the stator core due to a gap that may be generated between the end surface of the teeth on the coil end side and the coil, can be solved. Not sure.

JP 2011-244596 A

  The present invention has been made in view of the above-described problems, and can securely fix the tooth and the coil without using a varnish and without the coil being displaced in the axial direction of the stator core with respect to the tooth. It is an object to provide a stator in which a fixing method, teeth and coils are firmly fixed.

  In order to achieve the above object, the method of fixing a coil to a tooth according to the present invention is to fix a coil around a tooth of a stator core in which a plurality of teeth protrude radially inward from an annular yoke and a slot is formed between the teeth. The first step is to take a slip prevention measure to prevent the coil from shifting in the axial direction of the stator core on the end surface of the teeth on the coil end side. A cylindrical thermally expandable sheet is placed around the teeth. A second step of disposing, a third step of forming a coil around a cylindrical thermally expandable sheet around the teeth, at least the thermally expandable sheet is heated and expanded, and the expanded thermally expandable sheet is passed through. And a fourth step of fixing the coil around the teeth.

  The method of fixing the coil to the teeth of the present invention is a cylindrical thermal expansion sheet after taking measures to prevent the coil from shifting in the axial direction of the stator core on the end surface on the coil end side of the tooth. Is arranged around the teeth, then a coil is formed, and the thermally expandable sheet is heated and expanded to fix the teeth and the coil. In this fixing structure, the end surface of the teeth on the coil end side is fixed. By not generating a gap between the coils, it is possible to effectively suppress the shift of the coils in the axial direction of the stator core.

  Here, the thermally expandable sheet to be applied is not particularly limited, but a foamed plastic sheet (such as a foaming agent dispersed therein) or the like can be applied.

  In addition, the coil may be a round wire coil with a circular cross section or a flat wire capable of improving the space factor, and any of which an insulating coating such as enamel is formed can be applied. . Further, the method of forming the coil may be a method of concentrated winding of the conducting wire or a method of distributed winding.

  Here, as the “deviation prevention measure” in the first step, the following embodiment can be exemplified.

  One embodiment of the slip prevention measure is to dispose a spacer that fills the gap between the end surface of the teeth on the coil end side and the thermally expandable sheet.

  As for the shape of this spacer, the gap shape that can be formed when the coil is formed around the teeth is specified from the actual manufactured product, and the shape of the spacer is set so as to be the same shape as this gap shape or a complementary shape. Is done. In general, above the end surface of the teeth on the coil end side, the coil is bent at the edge of one slot surface of the teeth and extends to the coil end, so that a semicircular or semi-elliptical gap is easily formed. .

  Therefore, for example, in the first step, a spacer having a semicircular or semi-elliptical cross section is disposed and fixed on the end surface on the coil end side of the tooth, and in the second step, the cylindrical thermal expansion sheet is fixed. By disposing around the teeth and the spacer, it is possible to eliminate a gap that may occur at the end of the teeth on the coil end side in the second step.

  When the coil is formed in the third step, even if there is a slight gap between the cylindrical thermally expandable sheet and the coil, the thermally expandable sheet is heated and expanded in the fourth step. Thus, the gap can be completely closed, and both the teeth and the coil can be firmly fixed in a posture in which both the teeth and the coil are pressed by the expanded thermal expansion sheet.

  According to this method, a varnish is not used when the coil is fixed to the teeth, and no gap is generated between the coil end-side end surface of the teeth and the coil, so that the coil is displaced in the axial direction of the stator core. I don't get it. Therefore, this is a fixing method suitable for all motors in recent years, in which the coil space factor is high and impregnation with varnish is not easy.

  In addition, by using a tubular thermally expandable sheet, it is possible to position the thermally expandable sheet simply by fitting it into the teeth without performing any processing (folding or the like). Further, by applying an adhesive material to the thermally expandable sheet, the thermally expandable sheet can be adhered and fixed to the side surface of the teeth and the periphery of the spacer when the thermally expandable sheet is fitted into the teeth.

  Here, by setting those materials so that the value of the coefficient of thermal expansion of the spacer is not less than the coefficient of thermal expansion of the teeth and not more than the coefficient of thermal expansion of the coil, the spacer and the thermally expandable sheet When the spacer is cooled and volume contracted after being heated and expanded, the volume contraction amount becomes smaller than the volume contraction amount of the coil so that no gap is generated between the coil and the spacer. .

  For example, when the thermal expansion coefficients of spacers, teeth, and coils are the same or substantially the same, the thermal expansion amount and the thermal contraction amount thereof are approximately the same. It is possible to prevent a gap from being generated between the coil and the spacer and between the spacer and the tooth.

  Moreover, other embodiment of a slip prevention measure is forming the end surface by the side of the coil end of teeth in the shape of a curve.

  The stator core can be manufactured from a laminated body in which electromagnetic steel sheets are laminated or a powder compact formed by pressure-sintering a powder magnetic core. When the stator core is manufactured, the end surface of the teeth on the coil end side has a cross-section. It is manufactured in a protruding manner so as to form a curved shape. In addition to the stator core having an annular overall shape, it may be a stator core having an annular overall shape by connecting the divided cores in the circumferential direction (divided stator core).

  Here, the “curved shape” means a semicircular shape or a semielliptical shape, which is a general gap shape described above.

  By projecting the end face on the coil end side of the tooth in a curved shape in advance, in the second step, the curved projecting portion is thermally expanded when the cylindrical thermally expandable sheet is disposed around the tooth. The adhesive sheet can be brought into close contact with each other, and a gap that can occur at the end of the tooth on the coil end side in the second step can be eliminated.

  The present invention also extends to a stator. In this stator, a plurality of teeth protrude radially inward from an annular yoke, and a coil is fixed around the teeth of the stator core in which slots are formed between the teeth. A spacer that is a displacement prevention measure for preventing the coil from shifting in the axial direction of the stator core on the end surface of the tooth on the coil end side of the stator, and has a cylindrical thermal expansion so as to surround the teeth and the spacer An expandable sheet is disposed, a coil is disposed around the thermally expandable sheet, and the coil is fixed to the teeth via the thermally expanded sheet.

  A coil for teeth is configured by a configuration in which a thermally expandable sheet is disposed around spacers and teeth, which are measures for preventing slippage, and a coil is disposed around the thermally expandable sheet and the thermally expandable sheet is thermally expanded. A strong fixing structure is formed. In particular, since the spacer is disposed on the end surface on the coil end side of the tooth, the gap that may be generated between the coil and the end surface of the tooth is eliminated, and this effectively suppresses the deviation of the coil, This greatly contributes to the strong fixing structure of teeth and coils.

  Another embodiment of the stator according to the present invention is a stator in which a plurality of teeth protrude radially inward from an annular yoke and a coil is fixed around the teeth of the stator core in which slots are formed between the teeth. In order to prevent the coil from shifting in the axial direction of the stator core, the end surface on the coil end side of the teeth protrudes in a curved shape, and a cylindrical thermally expandable sheet is arranged so as to surround the teeth. The coil is provided around the thermally expandable sheet, and the coil is fixed to the teeth via the thermally expanded sheet.

  Also in the stator according to the present embodiment, the end face on the coil end side protrudes in a curved shape, so that a gap that may be generated between the coil and the end face of the tooth is eliminated, and the thermal expansibility interposed between the tooth and the coil. Combined with the thermal expansion of the sheet, the stator has a strong fixing structure for teeth and coils.

  As can be understood from the above description, according to the method of fixing a coil to a tooth of the present invention, a slip prevention measure for preventing the coil from shifting in the axial direction of the stator core is provided on the end surface on the coil end side of the tooth. In addition, a cylindrical heat-expandable sheet is arranged around the teeth, then a coil is formed, and the teeth and the coil are fixed by heating and expanding the heat-expandable sheet. Therefore, the coil and the teeth can be firmly fixed without using the varnish while eliminating the displacement of the coil in the axial direction of the stator core. Further, according to the stator of the present invention, a slip prevention measure is disposed on the end surface of the tooth on the coil end side, and a thermally expandable sheet is disposed so as to surround the teeth and the slip preventive measure. Since the coil is disposed around and the thermally expandable sheet is thermally expanded, the stator is provided with a strong connection structure between the teeth and the coils without being displaced from the teeth.

It is a figure explaining the 1st step of Embodiment 1 of the method of fixing a coil to the teeth of the present invention. FIG. 2 is a diagram illustrating a second step and a third step following FIG. 1. FIG. 4 is a diagram for explaining a fourth step following FIG. 2, and is a diagram showing a first embodiment of a stator formed by a fixing method. It is the figure explaining the 1st step of Embodiment 2 of the method of fixing a coil to the teeth of this invention.

  Hereinafter, a method of fixing a coil to the teeth of the present invention and a stator formed by this method will be described with reference to the drawings. In the illustrated method of fixing the coil to the teeth, the stator core to be used is in the form of an annular integral type made of a laminate of electromagnetic steel plates, but the stator core may be made up of divided cores. Further, in the illustrated example, a part of the annular stator core is extracted and illustrated, but it is needless to say that the stator is formed by applying the illustrated fixing method to all the teeth of the stator core.

(Method for fixing coil to teeth and embodiment 1 of stator)
FIG. 1 is a diagram for explaining a first step of the first embodiment of the method for fixing a coil to a tooth of the present invention, and FIG. 2 explains a second step and a third step following FIG. FIG. 3 is a diagram for explaining the fourth step subsequent to FIG. 2 and showing the first embodiment of the stator formed by the fixing method.

  A stator core 10 shown in the figure is formed by integrally forming a laminated body formed by laminating substantially annular electromagnetic steel plates 1 by caulking or the like, and is composed of an annular yoke 11 and teeth 12 projecting radially inward from the yoke 11. Has been. In addition to the electromagnetic steel sheet, the stator core 10 is formed of a steel sheet laminate formed by laminating steel sheets such as cold rolled steel sheet (SPCC), hot rolled steel sheet (SPHC), carbon steel (S45C), or soft magnetic metal. The powder or soft magnetic metal oxide powder may be formed from a powder magnetic core formed by pressure molding magnetic powder coated with a resin binder such as silicone resin or silica.

  Of the teeth 12 of the stator core 10, the columnar spacers 20, 30 having a semi-elliptical cross section are fixed to two end surfaces (upper end and lower end) on the coil end side via, for example, an adhesive or an adhesive sheet. In addition, the cross-sectional shape of the spacers 20 and 30 is not limited to a semi-elliptical shape, but may be a semi-circular shape or the like, which is complementary to the gap formed between the end surface of the coil end side of the teeth and the coil. desirable.

  The spacers 20 and 30 prevent a gap that may be generated between the tooth 12 and a coil (not shown). By preventing this gap, the coil is prevented from shifting in the axial direction (Y direction) of the stator core 10. It becomes a slip prevention means.

  Here, the material for forming the spacers 20 and 30 is not particularly limited, but the spacers 20 and 30 can be formed from a metal material having a linear expansion coefficient approximate to that of the electromagnetic steel sheet 1 or a rectangular wire for coil formation, or a filler. It may be formed from a PPS resin containing a large amount of.

  When the thermal expansion coefficients of the spacers 20 and 30, the teeth 12, and the coil are the same or substantially the same, the thermal expansion amount and the thermal contraction amount thereof are approximately the same. 30, it is possible to prevent a gap from being generated between the spacers 20 and 30 and the teeth 12. Further, when the materials are set so that the thermal expansion coefficient of the spacers 20 and 30 is equal to or larger than the thermal expansion coefficient of the teeth 12 and equal to or smaller than the thermal expansion coefficient of the coil, the spacers 20 and 30 are used. When the spacers 20 and 30 are cooled and volume contracted after the thermally expandable sheet 40 is heated and expanded, the volume contraction amount becomes smaller than the volume contraction amount of the coil, so that the coil and the spacers 20 and 30 are expanded. It is possible to prevent a gap from being generated between them.

  In this way, the spacers 20 and 30 are disposed on the upper and lower end surfaces of the teeth 12 of the teeth 12 of the stator core 10, and a deviation prevention measure is taken to prevent the coils from shifting in the axial direction of the stator core 10 (first step).

  Next, the tubular thermally expandable sheet 40 is fitted around the teeth 12 and the upper and lower spacers 20 and 30 (X direction) and disposed (second step).

  The heat-expandable sheet 40 may be made of a heat-expandable rubber sheet, a heat-expandable foamed plastic sheet (such as one in which a foaming agent is dispersed), or a heat-expandable mat obtained by bonding fiber materials with an inorganic binder resin. it can.

  For example, by using a thermally expandable sheet 40 made of a material in which a foaming agent is dispersed in a thermosetting resin such as an epoxy resin or an unsaturated polyester resin, it has thermal expandability and adhesiveness. When the sheet 40 is fitted, the teeth 12 and the spacers 20 and 30 can be bonded to the heat-expandable sheet 40 to integrate them.

  Next, a coil is formed as shown in FIG. 2 by winding a rectangular wire 50 around the thermally expandable sheet 40 disposed on the outer periphery of the tooth 12 (third step).

  The flat wire 50 is formed by forming an insulating film around a flat wire made of copper, and a coil is formed by edgewise winding the flat wire 50 around the teeth 12. By forming the coil from the flat wire 50, the space factor of the coil in the slot 13 is improved.

  The cross-sectional shape (semi-elliptical shape) and dimensions of the spacers 20 and 30 are specified in advance as the shape and dimensions of the gap formed above the end surface on the coil end side of the teeth when a rectangular wire is wound as shown in the figure. By providing the spacers 20 and 30 satisfying the specified shape and dimensions, a gap cannot be formed between the end face on the coil end side of the tooth 12 and the coil 50 as shown in the figure when the coil is formed.

  Next, the thermal expansion sheet 40 is thermally expanded by heat-treating the vicinity of the teeth 12, the spacers 20 and 30, and the thermally expandable sheet 40, thereby generating a pressure q on the teeth 12 inside the thermally expandable sheet 40. Similarly, by generating a pressure q also on the coil 50 outside the thermally expandable sheet 40, the teeth 12 and the coil 50 are fixed via the expanded thermally expandable sheet 40. The stator 200 including the fixed structure 100 is formed (fourth step).

  Even if there is a slight gap between the thermally expandable sheet 40 and the coil 50 in the stage of the third step, the gap is caused by the thermal expansion of the thermally expandable sheet 40 in the fourth step. Can be completely occluded.

  According to the stator 200 shown in FIG. 3, there is no gap between the coil end side end surface of the tooth 12 and the coil 50, and thus there may be a problem that the coil is displaced in the axial direction of the stator core when there is a gap. Absent.

  In addition, since the coil is formed using the flat wire 50, the space factor in the slot is increased, and there is no sufficient gap between the flat wires or between the teeth and the flat wire for impregnation of the varnish. Even in this case, the teeth 12 and the coil 50 can be firmly fixed without using a varnish.

(Embodiment 2 of a method for fixing a coil to a tooth)
FIG. 4 is a diagram for explaining a first step of the second embodiment of the method for fixing a coil to the teeth of the present invention. In the illustrated fixing method of the second embodiment, the second step to the fourth step are the same as the fixing method of the first embodiment, and thus the description thereof is omitted. The illustration of the stator formed by this fixing method is also omitted.

  In this embodiment, instead of fixing the spacers on the upper and lower end surfaces of the teeth 12 with an adhesive or the like, the cross section of the end surface of the teeth on the coil end side is curved at the stage of manufacturing the stator core 10A by laminating electromagnetic steel sheets. The projecting portions 20A and 30A (semi-elliptical in the figure) are formed from a laminate of electromagnetic steel sheets.

  As described above, the fixing method according to the present embodiment is to take a shift prevention measure (preliminarily manufactured) for preventing the coil from being displaced in the axial direction of the stator core at the stage of manufacturing the stator core 10A.

  As described above, the stator core in which the curved protruding portion is formed on the end surface on the coil end side of the teeth may be molded with a powder compact formed of a powder magnetic core.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Magnetic steel plate 10, 10A ... Stator core, 11 ... York, 12 ... Teeth, 13 ... Slot, 20, 30 ... Spacer, 20A, 30A ... Curved projection part, 40 ... Thermal expansion sheet, 50 ... Rectangular wire (Coil), 100 ... Teeth and coil fixing structure, 200 ... Stator

Claims (7)

A method of fixing a coil around teeth of a stator core in which a plurality of teeth protrude radially inward from an annular yoke and slots are formed between the teeth,
A first step of taking a slip prevention measure to prevent the coil from shifting in the axial direction of the stator core on the end surface of the teeth on the coil end side;
A second step of disposing a tubular thermally expandable sheet around the teeth;
A third step of forming a coil around a cylindrical thermally expandable sheet around the teeth;
The method of fixing a coil to the teeth which consists of a 4th step which heats and expands a thermally expansible sheet at least, and fixes a coil around teeth via the expanded thermally expansible sheet. In the first step, the slip prevention measure is to dispose a spacer that fills a gap between the end surface of the tooth on the coil end side and the thermally expandable sheet,
The method of fixing a coil to the teeth according to claim 1, wherein in the second step, a cylindrical thermally expandable sheet is disposed around the teeth and the spacers. In the first step, the slip prevention measure is to project the end surface on the coil end side of the teeth in a curved shape,
2. The method of fixing a coil to a tooth according to claim 1, wherein, in the second step, a curved protruding portion is brought into close contact with the thermally expandable sheet when the cylindrical thermally expandable sheet is disposed around the teeth. .   The method for fixing a coil to a tooth according to claim 2, wherein a value of a coefficient of thermal expansion of the spacer is not less than a coefficient of thermal expansion of the tooth and not more than a coefficient of thermal expansion of the coil.   The method for fixing a coil to a tooth according to claim 2, wherein the thermal expansion coefficients of the spacer, the tooth, and the coil are the same or substantially the same. A stator in which a plurality of teeth protrude radially inward from an annular yoke and coils are fixed around the teeth of the stator core in which slots are formed between the teeth,
A spacer, which is a displacement prevention measure for preventing the coil from shifting in the axial direction of the stator core, is disposed on the end surface on the coil end side of the tooth,
A cylindrical thermally expandable sheet is disposed so as to surround the teeth and the spacer, and a coil is disposed around the thermally expandable sheet, and the coil is connected to the teeth via the thermally expanded sheet. A fixed stator. A stator in which a plurality of teeth protrude radially inward from an annular yoke and coils are fixed around the teeth of the stator core in which slots are formed between the teeth,
As a slip prevention measure to prevent the coil from shifting in the axial direction of the stator core, the end surface on the coil end side of the teeth protrudes in a curved shape,
A cylindrical thermally expandable sheet is disposed so as to surround the teeth, and a coil is disposed around the thermally expandable sheet, and the coil is fixed to the teeth via the thermally expanded sheet. Stator.

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