JP2011019296A - Stator with insulator and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stator with an insulator having the same superior heat dissipation as that of an integrally molded insulator, and capable of preventing a problem that damage such as cracks are caused in the insulator due to an external force acting on the insulator from a steel plate laminate in accordance with stress release in the integrally molded insulator, and to provide a method of manufacturing the stator.SOLUTION: In the split stator core 10 with a yoke 11 and teeth 12 protruding from the yoke 11 to the inside of a diameter direction, the split stator 100 includes an insulator 20 at least around the teeth 12. In the insulator 20, at least two split bodies 21, 22 are fitted into both ends of the teeth 12, respectively, the split bodies 21, 22 are bonded to each other via a weld-bonding part 23, and the split bodies 21, 22 are closely bonded to the split stator core 10.

Description

  The present invention relates to a stator in which an insulator is formed at least on the outer periphery of a tooth, a method for manufacturing the stator, and a motor including the stator.

  In the automobile industry, with the aim of further improving the running performance of hybrid cars and electric cars, developments for driving motors with higher output, lighter weight, and smaller size are in progress every day. In addition, home appliance manufacturers have no choice but to develop further miniaturization and higher performance of motors incorporated in various home appliances.

  A stator constituting a motor (electric motor) is a stator core formed by laminating steel plates each having an annular yoke, a plurality of teeth projecting radially inward from the yoke, and slots formed between adjacent teeth. The stator is manufactured by being wound between the teeth while the coil is inserted into the slot. Here, there are a concentrated winding method and a distributed winding method for winding the conductive wire for the coil. The concentrated winding method is a mode in which a conductor is wound for each tooth, and the distributed winding method is a plurality of teeth. It is the form by which a conducting wire is wound over. In any of the winding methods, slot insulating paper is interposed between them from the viewpoint of ensuring insulation between the slot wall surface and the coil. However, when insulation between the coil and the core is intended with this insulating paper, it cannot be avoided that an air layer is formed between the insulating paper and the core, and this air layer increases the thermal resistance. This is a cause of reducing the heat dissipation to the core of Joule heat generated in the coil when the motor is driven.

  Therefore, a measure is taken to form an insulator by integrally forming a resin of an insulating material around, for example, a tooth so as to ensure the adhesion between the insulator and the core and not to form an air layer therebetween. Note that Patent Document 1 discloses a split stator core in which an insulator is formed by this integral molding. In this divided stator core, a guide groove for guiding the coil is provided on the tooth base end side of the yoke.

  From the viewpoint of miniaturization of the motor and heat dissipation, the integrally molded insulator described above is preferably a thin layer as much as possible. However, for example, if the insulator thickness is reduced to increase heat dissipation, Insufficient filling during molding is likely to occur, and furthermore, the linear expansion coefficient of the resin insulator is much higher than that of the core, so that cracks due to temperature stress tend to occur depending on the use environment. Even when an inorganic filler is contained in the resin in order to improve the heat dissipation, the fluidity of the resin is lowered, and similarly, filling failure at the time of injection molding is likely to occur.

  In this way, when an insulator is formed by integrally molding a resin around the teeth, high thermal conductivity, good filling based on high fluidity, and high strength (crack resistance) are mutually contradictory. The material approach that satisfies all the factors is extremely difficult.

  Further, in the method of forming an insulator by integrally molding the resin, when the insulator is molded at least on the outer periphery of the teeth in the molding die, the teeth receive excessive resin pressure, and then the mold is removed from the molding die. Then, the laminated steel sheet bulges outward so as to release the stress received at the time of forming, and an external force resulting from the bulge is applied to the outer insulator. It is easy to understand that such an external force hinders the durability of the insulator, and in some cases, there is a risk of generating a crack within a short period of time.

  Furthermore, when the insulator is molded, the resin leaks from the cavity and hardens to become burrs, which may be an obstacle when assembling the split core.

  Here, to turn to the conventional open technology, the insulators are fitted on the top and bottom of the teeth, the insulating sheets are arranged on the side surfaces of the teeth, and a part of these insulators and a part of the insulating sheet are welded. Patent Document 2 discloses an armature that forms an insulator.

JP-A-11-332138 JP 2008-206322 A

  According to the armature disclosed in Patent Document 2, the above-described problem when the insulator is integrally formed on the outer periphery of the tooth, that is, the steel sheet laminate that forms the tooth by releasing the excessive resin pressure that acts during the molding at the time of demolding. The problem that the durability of the insulator is reduced by the external force acting from the above, and that it is difficult to assemble the divided cores due to burrs that may occur during molding cannot occur. However, by simply welding a part of the insulator and a part of the insulating sheet, it is not possible to eliminate a gap that may be generated between the teeth and the insulator and the insulating sheet. The effect that is achieved, that is, the excellent thermal conductivity and heat dissipation effect that are achieved by the close contact between the insulator and the tooth cannot be obtained.

  The present invention has been made in view of the above-described problems, and has an excellent heat dissipation performance similar to that of an integrally molded insulator. Further, like the integrally molded insulator, the present invention is made from the stator core as the stress is released. It is an object of the present invention to provide a stator including an insulator and a method for manufacturing the stator, in which a problem such as cracking of the insulator due to an external force that can act on the insulator cannot occur.

  In order to achieve the above object, a stator having an insulator according to the present invention is a stator core or a divided stator core comprising a yoke having a substantially annular or substantially arc shape in plan view and teeth projecting radially inward from the yoke. A stator having an insulator around the teeth, wherein the insulator has at least two divided bodies fitted on the outer periphery of the teeth, and the divided bodies are joined to each other via a welded joint. In addition, the divided body and the stator core or the divided stator core are in close contact with each other.

  The stator of the present invention is intended for both a substantially annular stator core in plan view and a split stator core constituting a split stator, and a substantially arc-shaped split stator core in plan view. In addition, the present invention relates to a stator assembled with an insulator formed in a separate body and having a substantially U-shaped front view. “At least the outer periphery of the teeth” means not only the outer periphery of the teeth but also includes a form extending on the side surface of the yoke facing the slot formed between adjacent teeth. Further, a flange may be provided on the yoke side end of the insulator, and a structure excellent in positioning of a coil wound around the insulator outer periphery may be exhibited.

  Here, a stator core (including a split stator core) having teeth to which an insulator is attached is formed from a steel sheet laminate formed by laminating electromagnetic steel sheets, and a dust core formed by press-molding magnetic powder. And those formed from high-density powder magnetic cores (HDMC) and the like. Here, as the magnetic powder, iron, iron-silicon alloy, iron-nitrogen alloy, iron-nickel alloy, iron-carbon alloy, iron-boron alloy, iron-cobalt alloy, iron-phosphorus Examples thereof include soft magnetic metal powders such as iron alloys, iron-nickel-cobalt alloys, and iron-aluminum-silicon alloys, or soft magnetic metal oxide powders coated with a resin binder such as silicone resin.

  Insulators that are molded separately and assembled to the outer periphery of the teeth in a later process are formed by injection molding of a resin material or the like of an insulating material. It is preferable that a filler is contained. In the stator of the present invention, since the insulator is not integrally molded on the outer periphery of the stator, even when a material containing an inorganic filler in the resin is used, its filling goodness in the mold is a problem. Therefore, an insulator that is as thin as possible and excellent in heat dissipation can be formed on the outer periphery of the teeth.

  In the stator according to the present invention, for example, a divided body of two insulators is fitted at least on the outer periphery of the teeth, and in this posture, the divided bodies are bonded to each other via a welded joint portion in which the joint ends of both divided bodies are welded together. The joining of is planned. In addition, the form by which three or more division bodies are fitted by the teeth outer periphery may be sufficient.

  Furthermore, by devising the manufacturing method, the insulator is not integrally formed on the outer periphery of the teeth, but there is no air gap between the stator core (including the divided stator core) and the divided body of the two insulators, It exhibits a structure that is in close contact with each other.

  Here, with respect to the fitting form of, for example, two divided bodies on the outer periphery of the teeth, the two divided bodies of the insulator having a substantially U-shape when viewed from the front are fitted from both sides of the teeth, and the welded joint portion is formed. Forms formed on the upper and lower ends of the teeth (longitudinal ends of the stator core), for example, two insulators are fitted from the upper and lower ends of the teeth, and the welded joints are on both sides of the teeth (the slots of the teeth). Any of the forms formed on the side surfaces facing each other.

  According to the above-described stator of the present invention, the above-described problem when the insulator is integrally formed in the outer periphery of the teeth in the molding die, that is, the high-pressure injected resin compresses the stator core and releases the stress at the time of demolding. The stator core in a compressed posture bulges outside, and the problem that the insulator can be cracked by external force acting on the insulator around the teeth due to the bulge, and the resin injected at high pressure when the stator core is compressed The problem that it may be necessary to remove the leaked and cured resin in a later process and effectively leak out to an insulator formation unnecessary portion of the stator core is effectively solved.

  In addition, a method of manufacturing a stator having an insulator according to the present invention provides a stator core or a divided stator core, which includes a yoke having a substantially annular or substantially arc shape in plan view and teeth projecting radially inward from the yoke. First step of preparing a divided body of divided insulators arranged at least on the outer periphery of the teeth, at least two of the divided bodies are arranged on the outer periphery of the teeth, and at least one of the divided bodies is joined to each other By melting and pressurizing the region, the second step includes joining of the divided bodies and a close contact between the divided bodies and the stator core or the divided stator core.

  In the second step, among, for example, two divided bodies fitted on the outer periphery of the teeth, at least a bonding region to be bonded to each other is melted and pressed to be bonded (welded) to each other. In this pressurization step, the stator core and the divided body are completely brought into close contact with each other, so that the contact posture between the stator core and the divided body can be formed at the same time when the joint portion between the divided bodies is welded. In addition, the welding of the joining region of the divided body is performed by incorporating a heating mechanism such as a heater wire in a predetermined portion of the mold, placing the stator core in a posture in which the divided body is fitted on the outer periphery of the tooth, and closing the mold. By operating the heating mechanism, it is possible to easily perform welding between the divided bodies.

  Here, in the second step described above, a so-called vibration welding method may be applied in which the bonding region between the insulators to be bonded is pressurized while being vibrated to melt and bond the bonding regions to each other. . Note that this vibration welding includes a method of generating strong frictional heat by transmitting vibration generated from ultrasonic energy to two divided bodies.

  This is because the divided body itself generates heat from the inside due to the action of the high frequency energy, and according to this method, it is possible to melt only the part to be welded, and therefore the finish becomes very beautiful, Insulators excellent in bonding strength can be formed by melting and bonding the base materials.

  Furthermore, the second step described above is preferably performed in a reduced pressure atmosphere or a vacuum atmosphere.

  For example, when a stator core in a posture in which a divided body is fitted to the outer periphery of a tooth is placed in a mold, and the mold is closed, the mold (cavity) is evacuated to create a reduced pressure atmosphere or a vacuum atmosphere. By performing the welding of the divided bodies in this atmosphere, the divided bodies and the stator core can be more reliably brought into close contact with each other.

  A motor including a stator including the insulator according to the present invention described above, a stator manufactured by the manufacturing method according to the present invention, and a rotor rotatably disposed in the stator is formed around the teeth. There is no damage such as cracks, and the adhesion posture between the thin insulator and the stator core is guaranteed as much as possible, and it has better insulation, heat dissipation and durability. Become a motor. Therefore, the motor including the stator of the present invention has recently been expanded, and is suitable for hybrid vehicles and electric vehicles that require higher durability and higher heat dissipation especially for a drive motor mounted on a vehicle. is there.

  As can be understood from the above description, according to the stator having the insulator of the present invention and the method for manufacturing the stator having the insulator, the divided parts of the insulator formed separately are fitted to the teeth, and both are welded. By doing so, the insulator and the stator core are in close contact with each other, and it has excellent thermal conductivity and can form a thin insulator as much as possible around the teeth without any damage. It is possible to obtain a stator including an insulator having excellent properties, and a motor including the stator.

It is the flowchart which outlined the manufacturing method of the stator of this invention. It is the perspective view explaining the condition which has fitted the division body of the insulator shape | molded separately by the division | segmentation stator core. The two insulators are assembled on the outer periphery of the teeth by the method shown in FIG. 1, and both joints are welded to form a welded joint, through which the two parts are joined. It is the perspective view which showed the division | segmentation stator core. It is a figure corresponding to FIG. 3, Comprising: It is the figure which showed other embodiment of the division | segmentation stator core. It is a perspective view which shows the stator by which a division | segmentation stator core is assembled | attached to the circumferential direction and a cylinder is shrink-fitted.

  Embodiments of the present invention will be described below with reference to the drawings. Although the illustrated example shows a split core, it is needless to say that a general stator integrally formed in an annular shape may be used. Moreover, although the example of illustration fits two division bodies around teeth, the form which fits three or more division bodies around teeth may be sufficient. Further, for clarity of illustration, the illustration of coils formed on the outer periphery of the insulator is omitted.

  FIG. 1 is a flowchart showing a method for manufacturing a stator having an insulator according to the present invention.

  The manufacturing method of the present invention will be outlined based on this figure. First, the divided stator core 10 and the two divided bodies 21 and 22 constituting the insulator are prepared (step S1).

  Here, the shape of the divided stator core 10 is maintained by laminating the electromagnetic steel plates 1,. It should be noted that the divided stator core may be formed from a dust core, a high-density dust core (HDMC), or the like in addition to the form in which the electromagnetic steel plates 1,.

  The formed divided stator core 10 includes a yoke 11 having a substantially arc shape in plan view, and a tooth 12 projecting radially inward from the yoke 11. As shown in the figure, a coil positioning projection is provided at the tip of the tooth. Is formed.

  On the other hand, the two divided bodies 21 and 22 constituting the insulator are separately molded by pressure-molding a resin of an insulating material in a mold. Here, as the resin of the insulating material, an appropriate thermosetting resin or thermoplastic resin can be used as the material, and from the viewpoint of further improving heat dissipation (thermal conductivity), these resin materials include inorganic fillers. You may shape | mold from the contained material. As an example of the material, any one of epoxy resin, polypropylene, polyethylene naphthalate, polyphenylene sulfide, polyimide, polyamide, and liquid crystal polymer can be used. Furthermore, silica, alumina, boron nitride, nitridation can be used for these resin materials. A material containing a filler such as silicon, silicon carbide, or magnesium oxide can be used.

  Here, the divided bodies 21 and 22 are fitted portions 21a and 21f fitted into the side surfaces 12a (side surfaces opposite to the slots) of the teeth 12 of the divided stator core 10 and the end surfaces 12b of the teeth 12 so as to surround them. 22a and flange portions 21b and 22b formed for the purpose of positioning the coil when a coil (not shown) is formed on the outer periphery.

  Next, as shown in FIG. 1, two divided bodies 21 and 22 are fitted to the teeth 12 from the upper and lower ends of the prepared divided stator core 10 (X direction), and both divided bodies are fitted in this fitted posture. With the contact end surfaces 21c and 22c of 21 and 22 in contact, they are accommodated in a molding die (not shown), and the molding die is closed (step S2).

  A molding die (not shown) is provided with a vibration generating mechanism or an ultrasonic wave generation mechanism, and the molding die in the mold closing posture applies these vibrations (energy) to the divided parts 21 and 22 of the insulator therein. Are pressed against each other to generate frictional heat on the contact end faces 21c and 22c, and to continuously integrate the joined portions while melting both of them (by vibration welding in FIG. Bonding step S3).

  Here, when welding the contact end faces 21c, 22c of both the two divided bodies 21, 22 by vibration welding, by pressing each divided body 21, 22 from the side with a molding die (not shown), The side surface 12a of the tooth 12 and the divided bodies 21 and 22 are preferably brought into close contact with each other. In addition, although the pressurization force in the case of this pressurization acts on the division bodies 21 and 22, it does not compress a stator core like the case where the insulator of the conventional method is integrally formed in the teeth outer periphery.

  When joining the divided bodies 21 and 22, the inside of the mold cavity may be evacuated, and the inside of the cavity may be in a reduced pressure atmosphere or a vacuum atmosphere (step S5). By reducing the pressure in the cavity, the adhesion between the side surface 12a of the tooth 12 and the divided bodies 21 and 22 can be further promoted.

  When the split stator core 10 is taken out of the mold after waiting for the joint regions of both the melted divided bodies 21 and 22 to harden, the stator core having the insulator 20 including the two divided bodies 21 and 22 as shown in FIG. (Divided stator core) is obtained (step S4).

  In the method of manufacturing the split stator core 10 described above, in the process of forming the insulator 20 on the outer periphery of the tooth 12, no compressive force that compresses the split stator core is applied, so that it was accumulated in the stator core at the time of demolding. The compressive force is released, and there is no risk that this acts on the insulator split and causes the insulator to crack.

  The insulator 20 formed on the outer periphery of the tooth 12 is configured such that the contact end surfaces of the two divided bodies 21 and 22 are integrated by vibration welding to form a welding line 23, and the divided stator core 10 and the insulator 20 are in close contact with each other. Thus, the split stator core 10 has no air gap between them. Therefore, the heat generated when the coil formed on the outer periphery of the insulator 20 generates heat can be effectively radiated to the core via the insulator 20, and a stator having excellent heat dissipation performance is formed.

  FIG. 4 shows an insulator 20A according to another embodiment of the insulator 20 shown in FIG.

  In this insulator 20A, welding lines 23A of two divided bodies 21A and 22A constituting the insulator 20A are formed on the upper and lower end surfaces of the tooth 12.

  FIG. 5 is a perspective view showing a split stator 100 in which the split stator cores 10 shown in FIG. 3 are assembled in the circumferential direction. In addition, illustration of the coil around an insulator is abbreviate | omitted.

  Specifically, the divided stator cores 10,... Are assembled in the circumferential direction to form an annular stator core, and the cylindrical body 30 is fitted on the outer periphery, and the divided stator 100 is formed by shrink fitting. Note that a rotor in which a radix permanent magnet corresponding to the magnetic pole is embedded is arranged inside the divided stator 100, and further, the divided stator 100 and the upper and lower ends of the rotor are integrated with an end plate, whereby an IPM motor is obtained. Is configured.

  In the IPM motor having the illustrated split stator 100, an external force that causes cracks or the like does not act on the insulator in the insulator forming process, and the stator core and the insulator form a close contact posture with each other. A split stator 100, and thus an IPM motor, which is excellent in heat dissipation performance for dissipating Joule heat that can be generated in the coil to the stator core via the insulator and excellent in durability can be obtained.

  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 ... Electromagnetic steel sheet, 10 ... Divided stator core, 11 ... Yoke, 12 '... Teeth, 21, 21A, 22, 22B ... Divided body of insulator, 20, 20A ... Insulator, 100 ... Divided stator

Claims (5)

A stator core or a split stator core comprising a substantially annular or substantially arc-shaped yoke in plan view and teeth projecting radially inward from the yoke, and a stator including an insulator at least around the teeth,
The insulator is formed by fitting at least two divided bodies on the outer periphery of the teeth, and the divided bodies are joined to each other through a welded joint, and the divided body and the stator core or the divided stator core And a stator having an insulator.   The motor which consists of a stator which comprises the insulator of Claim 1, and a rotor. A stator core or split stator core comprising a yoke having a substantially annular or substantially arc shape in plan view and teeth projecting radially inward from the yoke, and at least a divided insulator divided body disposed on the outer periphery of the teeth A first step of preparing
At least two of the divided bodies are disposed on the outer periphery of the teeth, and at least a joining region to be joined to each other is melted and pressed, thereby joining the divided bodies, and the divided bodies and the stator core. Or the manufacturing method of the stator which comprises the insulator which consists of a 2nd process which aims at contact | adherence with a division | segmentation stator core.   The manufacturing method of the stator which comprises the insulator of Claim 3 which melts and joins this joining area | region by pressurizing, vibrating the joining area | region of the insulators joined.   The manufacturing method of the stator which comprises the insulator of Claim 3 or 4 with which the said 2nd process is performed in a pressure-reduced atmosphere or a vacuum atmosphere.

Images