JP2013128339A - Stator for motor and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stator for a motor and a manufacturing method thereof capable of solving the problems in which: varnish impregnated among coils so as to achieve fixing of the coils to a stator core is impregnated among conductive wires constituting the coils and reaches wall surfaces of slots; the varnish is further impregnated among steel plates via gaps among the steel plates facing the wall surfaces of the slots; the varnish reaches holes for insertion of bolts positioned outside a yoke and enters the holes; and axial force of the bolts at the time of bolt tightening is reduced due to creep deformation of the varnish entered.SOLUTION: On wall surfaces of slots 1c constituted of lateral surfaces of teeth 1b and an inner peripheral surface of a yoke 1a, coating layers 8 made of a resin material are formed, and coils 4 are fixed to a stator core 1 by varnish. It is preferable that the coating layers 8 be formed of an ultraviolet curing resin.

Description

  The present invention relates to a motor stator and a method for manufacturing the same.

  A stator that constitutes a motor (electric motor) includes an annular yoke, a plurality of teeth projecting radially inward from the yoke, slots formed between adjacent teeth, and projecting outward from the outer peripheral surface of the yoke. It is generally composed of a protrusion having a hole for inserting a bolt, a steel sheet laminate comprising a coil, a coil formed around the teeth, and a case for accommodating the steel sheet laminate, and is inserted into the hole of the protrusion. A motor stator is formed by fastening a bolt between the upper end surface of the steel sheet laminate and the case.

  The coil conductor is generally circular in cross section, and for example, a conductor made of a copper material and an insulating film formed around the conductor is applied (this coil is called a round wire). For the purpose of improving the space factor, for example, a coil in which an insulating film is formed around a rectangular wire made of copper is edgewise wound may be used.

  As a method of forming a coil around the teeth, for example, a method in which a coil is formed by winding a conductor wire in advance is fitted from the tip (rotor side) of the teeth, or a winding device is used to turn the winding to the teeth for a predetermined turn. There are methods such as making a coil by winding several turns. In any method, after the coil is formed around the teeth, the coil and the teeth are fixed, and the air gap between the coil and the teeth is closed to effectively generate the heat generated in the coils. In order to achieve the purpose of increasing heat dissipation by transferring heat, impregnating varnish between the windings constituting the coil and between the coil and the stator core, and heating the whole to thermally cure the varnish, the stator core The coil is fixed to

  In the stator configured as described above, the varnish impregnated between the coils formed around the teeth to fix the coil and the stator core impregnates between the conductors constituting the coil and reaches the wall surface of the slot, and then faces the wall surface of the slot. Even if the steel plate laminate and the case are firmly fastened with bolts, it is impregnated between the steel plates via the gap between the steel plates and reaches the bolt insertion hole outside the yoke and enters here. There is a risk that the bolt axial force at the time of fastening is reduced due to creep deformation of the varnish.

  In general, the conductive wire forming the coil is intricately entangled around the teeth, and it is necessary to impregnate the varnish through the entangled gap, so the varnish requires good impregnation, that is, good wettability to the coil. Thus, after impregnating between the coils because of the varnish having a good impregnation property, the steel sheets constituting the steel sheet laminate are easily impregnated.

  Therefore, in the conventional motor stator having the above configuration, how to prevent the varnish impregnated in the coil formed around the teeth from being impregnated between the steel plates constituting the steel plate laminate is a problem to be solved in the technical field. It has become one of the.

  In addition, as in the stator disclosed in Patent Document 1, a method of forming a coil after interposing a slot insulating paper on the inside of the wall surface of the slot and impregnating the varnish is generally performed. Even in the case of applying varnish, the varnish impregnated inside the slot insulation paper (slot wall surface side) is impregnated as it is in the gap between the steel plates, so the varnish between the steel plates can be eliminated with the slot insulation paper. I can't.

JP 2007-274762 A

  The present invention has been made in view of the above-described problems, and in a stator for a motor, a varnish impregnated between coils formed around teeth in order to fix the coil and the stator core impregnates between conductors constituting the coil. To the slot wall surface, and further impregnated between the steel plates through the gap between the steel plates facing the slot wall surface, reaching the bolt insertion hole outside the yoke and entering here, and entering here It is an object of the present invention to provide a motor stator and a method for manufacturing the same that can solve the problem that the bolt axial force at the time of fastening decreases due to creep deformation of the varnish.

  In order to achieve the above object, a motor stator according to the present invention includes an annular yoke formed by laminating steel plates, teeth projecting radially from the yoke, side surfaces of the teeth, and an inner peripheral surface of the yoke. In a stator core for a motor composed of a slot formed, a protrusion protruding outward is formed on the outer peripheral surface of the yoke, and a hole extending in the stacking direction of the steel plates is formed in the protrusion, and a coil is formed around the teeth. Is a stator for a motor in which a bolt inserted through the hole is fastened between the upper end surface of the steel plate and the case, and the slot wall surface is coated with a resin material. A layer is formed, and the coil is fixed to the stator core with a varnish.

  The stator for a motor of the present invention has a coating layer for preventing the varnish from entering between the steel plates from the slot side on the wall surface of the yoke.

  This coating layer is a layer of a resin material, and a material capable of forming a layer by curing a liquid (including slurry) resin as quickly as possible in the formation process. This is because, in the case of a material that takes time until it hardens itself, it may be impregnated between the steel plates to reach the holes and harden here.

  Examples of the material resin include an ultraviolet curable resin, an ultraviolet curable unsaturated polyester, a thione polymerization type ultraviolet curable epoxy resin, and the like.

  As the varnish for fixing the coil, a thermosetting resin such as an epoxy resin, an unsaturated polyester, or a phenol resin is generally applied.

  Further, the applied coil may be a round wire coil having a circular cross section, or a flat wire capable of improving the space factor. Various winding forms such as distributed winding, concentrated winding, edgewise winding of a rectangular wire, and segment coil winding (SC winding) can be applied to the winding form of the conductive wire around the teeth. In addition, an insulating material made of aluminum, aluminum alloy, or resin can be applied to the case for fixing the stator core while pressing the steel plates as desired.

  In the above-described stator for motors, in addition to the form in which the coating layer of the resin material is formed only on the wall surface of the yoke of the steel plate laminate, in addition to this, the outer periphery of the stator core (including the outer periphery of the protrusion) The stator in which the coating layer was formed may be sufficient. In the latter form, it is possible to completely prevent the varnish from entering between the steel plates from the inside and outside of the steel plate laminate.

  Further, the above-described coating layer is formed on the wall surface of the stator core slot, and further on the outer peripheral surface of the stator core, and the conventional slot insulating paper is disposed further inside (slot side) of the coating layer formed on the wall surface of the slot. Also good.

  According to the motor stator of the present invention described above, the varnish impregnated between the conductors for fixing the coil to the stator core is prevented from impregnating between the steel plates of the steel plate laminate from the slot side, and the varnish is interposed between the steel plates. The problem when impregnating and reaching the hole for bolt insertion, that is, the varnish that has impregnated between the steel plates and reached the hole hardens here, and the desired axial force of the bolt decreases due to its creep deformation The problem is solved.

  The present invention also extends to a method for manufacturing a stator for a motor. The manufacturing method includes laminating steel plates, an annular yoke, a tooth projecting radially from the yoke, a side surface of the tooth, and a yoke. A steel plate constituting a stator core for a motor, comprising: a slot defined by the inner peripheral surface; a protrusion projecting outward from the outer peripheral surface of the yoke; and a hole extending in the stacking direction of the steel plates provided in the protrusion. A first step of forming a laminate, a second step of applying a resin to the wall surface of the slot of the steel plate laminate and curing to form a coating layer, forming a coil around the teeth, and a varnish between the coils The stator is impregnated and cured, and the coil is fixed to the stator core. The coil is accommodated in the case, the bolt is inserted into the hole, and the bolt is fastened between the upper end surface of the steel plate and the case. It is made of a third step of production.

  In the manufacturing method of the present invention, a coating layer of a resin material is formed in the second step on the wall surface of the slot constituting the steel sheet laminate formed in the first step.

  As described above, the resin material for forming the coating layer is preferably a material that can form a layer by curing a liquid resin (including slurry) as quickly as possible in the formation process. As described above, it is desirable to use an ultraviolet curable resin as the material.

  In the second step, a resin material coating layer may also be formed on the outer peripheral surface of the stator core and the outer peripheral surface of the protrusion.

  Furthermore, in the second step, the coating layer may be formed in a semi-cured state, and in the third step, both the varnish and the semi-cured coating layer may be completely cured.

  According to this method, the adhesiveness between the semi-cured coating layer and the varnish is further enhanced in the course of complete curing, and in addition to preventing the varnish from entering the steel sheet by the coating layer, the cured varnish is used. Further, the fixing strength when fixing the coil to the stator core through the hardened coating layer can be increased.

  As can be understood from the above description, according to the stator for a motor of the present invention and the method for manufacturing the same, a coating layer of a resin material that prevents at least the varnish from entering between the steel plates from the slot side on the wall surface of the stator slot. The varnish impregnated between the coils is impregnated between the conductive wires constituting the coil to reach the wall surface of the slot, and further through the gap between the steel plates facing the wall surface of the slot. Since the impregnation between the steel plates is eliminated, the impregnation between the steel plates causes the varnish to reach the bolt insertion hole on the outer side of the yoke and enter here, resulting from creep deformation of the varnish that enters Thus, the problem that the bolt axial force at the time of fastening decreases cannot occur.

It is a longitudinal cross-sectional view of the motor which comprises the stator for motors of this invention. It is an II-II arrow line view of FIG. FIG. 3 is an enlarged view of a part III in FIG. 2, in which a coil is removed for easy understanding.

  Embodiments of a motor stator and a method for manufacturing the same according to the present invention will be described below with reference to the drawings.

(Embodiment of motor stator and motor)
1 is a longitudinal sectional view of a motor having a motor stator according to the present invention, FIG. 2 is a view taken along the line II-II in FIG. 1, and FIG. 3 is an enlarged view of a portion III in FIG. It is the figure which removed the coil in order to make an understanding easy. A motor 30 shown in FIG. 1 is mainly composed of a stator 10, a case 5 to which the stator 10 is fixed via bolts 6, and a rotor 20 that is rotatably arranged with a rotating shaft 7 inside the stator 10. Yes.

  The stator 10 includes a stator core 1 in which a steel plate laminate formed by laminating steel plates 1 ′ such as electromagnetic steel plates having a substantially annular plane shape is fixed by caulking or the like, and an annular yoke that constitutes the stator core 1. The coil 4 formed around a plurality of teeth 1b projecting radially from 1a and a case 5 for fixing the stator core 1 via bolts 6 constitute the whole.

  The radix of the tooth 1b corresponds to the number of magnetic poles, and the conducting wire forming the coil 4 formed around the tooth 1b may be either a round wire or a flat wire, and the winding of the conducting wire around the tooth 1b is possible. Various winding forms such as distributed winding, concentrated winding, edgewise winding of a rectangular wire, segment coil winding (SC winding), etc. can be applied.

  The case 5 is provided with a concave groove into which the end of the bolt 6 is inserted and fixed. The case 5 accommodates the stator core 1 in a hole 1e formed in a protrusion 1d projecting from the outer periphery of the yoke 1a of the stator core 1. The stator core 1 is fixed to the case 5 in a posture in which the adhesiveness between the crimped steel plates 1 ′ is further enhanced by inserting the bolts 6 and tightening the nuts at the upper end of the steel plate laminate.

  In the stator 10, the coil 4 formed around the tooth 1 b is impregnated with a varnish (not shown) and cured between the coil 4 and the tooth 1 b, thereby fixing the coil 4 to the tooth 1 b. Although illustration is omitted, insulating paper may be interposed between the inner peripheral surface of the slot 1c and the coil 4, and the coil 4 is a U-phase, V-phase, or W-phase coil for three-phase alternating current. In the case of comprising, interphase insulating paper is interposed between each phase coil at the coil end. Moreover, as a varnish for fixing the coil 4, thermosetting resins, such as an epoxy resin, unsaturated polyester, and a phenol resin, are applied.

  On the other hand, the rotor 20 includes a rotor core 2 in which a steel plate laminate formed by laminating steel plates 2 ′ such as electromagnetic steel plates having a disk-like planar shape is fixed by caulking or the like, and a rotor slot formed in the rotor core 2. The rotary shaft 7 is fixed to the center of the rotor core 2.

  As shown in FIGS. 2 and 3, the varnish is prevented from entering between the steel plates from the slot side to the wall surface of the slot 1 c constituted by the side surface of the tooth 1 b and the inner peripheral surface of the yoke 1 a in the stator 10. A coating layer 8 made of an ultraviolet curable resin is formed.

  When the coating layer 8 is formed, for example, a liquid resin is applied to the wall surface of the slot 1c (coating, spreading, etc.). If it takes time for the resin to harden after application, The material resin itself that forms a layer for the purpose of preventing the intrusion of the metal impregnates between the steel plates, and the purpose cannot be achieved.

  That is, an insulating resin that is cured as soon as possible after being applied to the wall surface of the slot is desirable, and an ultraviolet curable resin is applied as such a material resin.

  Examples of the ultraviolet curable resin include an ultraviolet curable unsaturated polyester and a cationic polymerization type ultraviolet curable epoxy resin.

  When the coating layer 8 is formed on the wall surface of the slot 1c, the coil 4 is formed around the teeth 1b from the state shown in FIG. 3, and the coil 4 is impregnated with varnish to fix the coil 4 to the teeth 1b. The impregnation of the varnish between the steel plates 1 ′ and 1 ′ constituting the stator core 1 is effectively suppressed.

  As a result, the varnish is impregnated between the steel plates, and the varnish reaches the hole formed in the protrusion on the outer periphery of the stator core and hardens here, and the varnish cured in the hole after the bolt fastening is creep-deformed. Therefore, the problem that the bolt axial force decreases cannot occur.

  Although not shown, the coating layer 8 may be formed on the outer peripheral surface of the stator core 1 in addition to the wall surface of the slot 1c, and according to this configuration, the inner side of the stator core 1 may be used. Impregnation of the varnish between the steel plates from both the outside and the outside can be suppressed.

(Embodiment of manufacturing method of motor stator)
An outline of the manufacturing method of the stator 10 shown in the drawing is as follows. First, as a first step, the steel plate laminate shown in the figure is formed, and then, as a second step, an ultraviolet curable resin is applied to the wall surface of the slot 1c of the steel plate laminate. The coating layer 8 is formed by coating (coating or spraying) and irradiating with ultraviolet rays to cure it.

  When the coating layer 8 is formed on the wall surface of the slot 1c, as a third step, the coil 4 is formed by winding a conductive wire so as to straddle the teeth 1b and the coating layer 8, or the coil 4 that has already been formed is formed by the teeth 1b. After the coil end height is adjusted by moving the coil end of the coil 4 or deforming it as necessary, the varnish is impregnated in the coil 4 and heat-treated. The coil 4 is fixed to the teeth 1b by curing.

  The stator core 1 with the coil 4 fixed to the teeth 1b is accommodated in the case 5, the bolt 6 is inserted into the hole 1e formed in the protrusion 1d of the stator core 1, and the tip of the stator core 1 is fitted into the concave groove of the case 5. By fixing the bolt head at the upper end of the nut with a nut, the stator core 1 is fixed to the case 5 while further improving the adhesion between the crimped steel plates 1 ′, and the stator 10 is configured.

  If there is concern about the impregnation of the varnish between the outer peripheral surfaces of the stator core 1 between the steel plates, it is preferable to form a coating layer not only on the wall surface of the slot 1c but also on the outer peripheral surface of the stator core 1 in the third step.

  Alternatively, in the second step, the coating layer 8 may be formed in a semi-cured state, and in the third step, both the varnish and the semi-cured coating layer 8 may be completely cured.

  According to this method, in the process in which both the semi-cured coating layer 8 and the varnish are completely cured, the adhesion between the varnish and the varnish is further enhanced. 4 to the stator core 1, more specifically, the fixing strength at the time of fixing to the stator core 1 through the cured coating layer 8 can be increased through the cured varnish.

"Experiments and results of verifying the effect of the coating layer"
The inventors made a stator by the following four manufacturing methods (Examples, Comparative Examples 1 to 3) and conducted an experiment to verify the quality of the manufactured stator.

(Example)
In the manufacturing method according to the example, a liquid ultraviolet curable resin is applied to the wall surface of the slot of the steel sheet laminate constituting the stator core, and immediately after this application, ultraviolet irradiation is performed to cure the ultraviolet curable resin and form a coating layer. Formed.

  More specifically, an ultraviolet curable polyester having a viscosity of 1 Pas (25 ° C) is used as an ultraviolet curable resin, which is applied to a steel sheet laminate, and irradiated with ultraviolet rays for several seconds immediately after application to cure the ultraviolet curable polyester. I let you. Here, as a result of measuring the degree of impregnation of the ultraviolet curable polyester between the steel plates of the steel plate laminate until the ultraviolet curable polyester was cured, it was possible to suppress it to 1 mm or less from the wall surface of the slot. Therefore, in this embodiment, the coating layer can be formed while suppressing impregnation of the ultraviolet curable polyester between the steel plates.

  Next, a coil is formed by winding a conductive wire around the teeth, and a thermosetting varnish made of unsaturated polyester having a viscosity of 1 Pas (25 ° C) is applied to the coil preheated to about 80 ° C. The coil was fixed by impregnating over a minute and heating at 150 ° C. for about 10 minutes to cure the varnish.

  When the stator core manufactured by the above method is accommodated in the case, and the bolt is inserted into the hole formed in the stator core and fixed to the case with the bolt, there is no hardened varnish in the hole. The problem that the desired axial force imparted to the lowering due to the creep deformation of the varnish is completely eliminated.

(Comparative Example 1)
In the manufacturing method according to Comparative Example 1, the coil is formed around the teeth after inserting the insulating paper into the wall surface of the slot of the steel sheet laminate, and the viscosity is 1 Pas (25 ° C.) with respect to the coil preheated to about 80 ° C. A thermosetting varnish made of the above unsaturated polyester was impregnated over 2 to 3 minutes and heated at 150 ° C. for about 10 minutes to cure the varnish and fix the coil.

  The varnish impregnation between the steel plates of the steel plate laminate until the varnish hardened had reached the bolt insertion hole located 100 mm outside from the wall surface of the slot.

  The varnish is likely to be impregnated between the steel sheets because it takes several minutes until the varnish is thermally cured, and the viscosity of the varnish is lowered during the heating process and the varnish becomes easy to flow. Then, the varnish reaches the bolt insertion hole and hardens here, so that the intended axial force applied to the bolt by the creep deformation of the hardened varnish is reduced. .

(Comparative Example 2)
In the manufacturing method according to Comparative Example 2, the coil is formed around the teeth after inserting the insulating paper into the wall surface of the slot of the steel sheet laminate, and the viscosity is 30 Pas (25 ° C.) with respect to the coil preheated to about 80 ° C. A thermosetting varnish made of high viscosity unsaturated polyester was impregnated over 2 to 3 minutes, and heated at 150 ° C. for about 10 minutes to cure the varnish to fix the coil.

  By using a high-viscosity varnish, impregnation of the varnish between the steel plates of the steel plate laminate until the varnish was cured could be suppressed to a position about 30 mm inside from the wall surface of the slot.

  However, the use of a high-viscosity varnish resulted in inadequate impregnation of the varnish into the coil, resulting in failure to achieve the intended purpose of the varnish to fix the coil to the teeth. From this, it can be said that it is unsuitable to use a high viscosity varnish for fixing the coil to the teeth.

(Comparative Example 3)
The manufacturing method according to Comparative Example 3 uses a highly viscous unsaturated polyester having a viscosity of 30 Pas (25 ° C), which is applied to a steel sheet laminate and heated at 150 ° C for about 10 minutes to cure the varnish and coat A layer was formed.

  Although a varnish with high viscosity was used, the varnish was applied directly to the wall surface of the slot. Had reached the position.

  Next, a coil is formed by winding a conductive wire around the teeth, and a thermosetting varnish made of unsaturated polyester with a viscosity of 1 Pas (25 ° C) is applied to the coil preheated to about 80 ° C for a few minutes. It was impregnated and heated at 150 ° C. for about 10 minutes to cure the varnish and fix the coil.

  In the stator manufactured by the above method, it was possible to form a coating layer by using a high-viscosity varnish, but the result is that about 80 mm from the wall surface of the slot is impregnated inside, When the scale of the stator is further reduced and the position of the bolt insertion hole is less than 100 mm from the slot wall surface, this coating layer cannot be applied.

  Further, in Comparative Example 3, the coating layer formed by the high-viscosity varnish present at the tip of the teeth interferes with the rotor, resulting in hindering the rotational performance of the motor.

  Based on the above experimental results, it is preferable to provide a coating layer of a resin material on the wall surface of the slot of the stator core, and it is also preferable to use an ultraviolet curable resin that can form the coating layer in as short a time as possible. It has proven desirable.

  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 ... Stator core, 1 '... Steel plate, 1a ... Yoke, 1b ... Teeth, 1c ... Slot, 1d ... Projection, 1e ... Hole, 2 ... Rotor core, 2' ... Steel plate, 3 ... Permanent magnet, 4 ... Coil, 5 ... Case , 6 ... bolt, 7 ... rotating shaft, 8 ... coating layer, 10 ... stator, 20 ... rotor, 30 ... motor

Claims (7)

In a stator core for a motor, comprising: an annular yoke formed by laminating steel plates; a tooth projecting radially from the yoke; and a slot defined by a side surface of the tooth and an inner peripheral surface of the yoke. Protrusions projecting outwards are formed on the outer peripheral surface of the steel plate, and holes extending in the stacking direction of the steel plates are formed in the protrusions. A stator core having coils formed around the teeth is accommodated in the case, and The inserted bolt is a stator for a motor that is fastened between the upper end surface of the steel plate and the case,
A motor stator in which a coating layer of a resin material is formed on the wall surface of the slot, and the coil is fixed to the stator core with a varnish.   The motor stator according to claim 1, wherein a coating layer of a resin material is also formed on the outer peripheral surface of the stator core and the outer peripheral surface of the protrusion.   The motor stator according to claim 1, wherein the coating layer is made of an ultraviolet curable resin. Laminated steel plates, annular yoke, teeth projecting radially from the yoke, slots defined by side surfaces of the teeth and the inner circumferential surface of the yoke, and projections projecting outward from the outer circumferential surface of the yoke And a first step of forming a steel plate laminated body constituting a stator core for a motor comprising a hole extending in the lamination direction of the steel plates provided in the protrusion,
A second step of applying a resin to the wall surface of the slot of the steel sheet laminate and curing to form a coating layer;
Coils are formed around the teeth, varnish is impregnated between the coils, cured, and the coils are fixed to the stator core. The coils are accommodated in the case, bolts are inserted into the holes, and between the upper end surface of the steel plate and the case. A method for manufacturing a motor stator comprising a third step of manufacturing a motor stator by fastening bolts.   5. The method of manufacturing a motor stator according to claim 4, wherein in the second step, a coating layer of a resin material is also formed on the outer peripheral surface of the stator core and the outer peripheral surface of the protrusion.   The motor stator according to claim 4 or 5, wherein the coating layer is formed in a semi-cured state in the second step, and both the varnish and the semi-cured coating layer are completely cured in the third step. Manufacturing method.   The method for manufacturing a motor stator according to claim 4, wherein the coating layer is made of an ultraviolet curable resin.

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