JP2008187880A - Axial air-gap electric motor and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an axial air-gap electric motor having an insulator structure, with which a force of winding a coil will not concentrate at the corner portions of a stator iron core. <P>SOLUTION: Of the cover of a covered insulator 30 for covering the external circumference of a winding portion 24 of the stator iron core 23, an upper wall portion 33 in the radial direction is formed into an arc so that its thickness is gradually increased from both ends of the circumferential direction as going toward the center. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an axial air gap type electric motor in which a stator and a rotor are opposed to each other with a predetermined gap along the axial direction of a rotor output shaft, and more specifically, an insulator for insulating an outer periphery of a stator core. Concerning structure.

  An axial air gap type electric motor is an electric motor in which a rotor (rotor) is arranged oppositely with a predetermined gap on one or both sides of a stator (stator), and is a radial gap type electric motor such as an inner rotor type. Compared to the above, there is a feature that the thickness in the direction of the rotation axis can be reduced, that is, flattened.

  By the way, the axial air gap type electric motor is formed by connecting a plurality of fan-shaped core members in a ring shape in Patent Document 1. According to this, a stator can be easily formed only by winding a winding around one core member in advance, connecting them in an annular shape and connecting them.

  Each core member has a stator core and an insulator for insulatingly covering the outer periphery of the stator core leaving a tooth surface, and a plurality of coils are wound around the winding portion of the stator core via the insulator. Has been.

  This stator core is generally composed of a laminate in which electromagnetic steel plates are stacked in a trapezoidal shape along the radial direction, and an insulator is integrally provided on the outer periphery of the stator core by insert molding or the like.

  However, the core member using the laminated body of electromagnetic steel sheets for the stator core has the following problems. That is, in the axial air gap type electric motor, the winding part of the coil has a triangular or trapezoidal cross section, and there are acute corners. Therefore, when the coil is wound around the insulator, the coil winding force is applied to the corners of the stator core. Stress concentrates on the part.

  In addition, as in Patent Document 1, in the type in which the skew is provided at the end portion of the teeth surface of the stator core, compared to the type in which the skew is not provided, the cross-sectional triangle includes a corner portion having a more acute angle. A particularly large stress is concentrated on this corner. Thereby, there existed a possibility of producing a crack etc. in the insulator which opposes a corner | angular part. Furthermore, since a thick wire coil is wound around a high output type electric motor, the stress concentration at the corners is larger.

  Further, conventionally, burrs are formed on the periphery of the electromagnetic steel sheet at the time of cutting, and the insulator is often integrally formed with the burrs remaining. For this reason, cracks and the like were more likely to occur by concentrating stress on the burr. Furthermore, if the coil is repeatedly energized, the stator core repeatedly expands and contracts due to the thermal cycle, so that cracks are more likely to appear.

  Therefore, as a method for effectively dispersing the stress relating to the corner, there is also a method of chamfering the corner of the insulator in an arc shape as shown in Patent Document 2, for example. However, the method described in Patent Document 2 has a chamfering center at the corner of the stator core, so that the winding force can be dispersed only to some extent, and it is possible to fundamentally solve the stress concentration on the burr. Absent.

JP 2007-6699 A JP 2006-20387 A

  Therefore, in order to solve the above-described problems, the present invention provides an axial air gap type electric motor including a stator in which a core member having an insulator structure in which a coil winding force is not concentrated on a corner portion of a stator core is annularly connected. It is to provide.

  In order to solve the above-described problems, the present invention has several features described below. According to a first aspect of the present invention, there is provided a stator in which a winding portion of a stator core has a plurality of core members covered with an insulator, and each of the core members is annularly arranged around the axis of the rotor output shaft. In the axial air gap type electric motor having the above, the insulator has a thickness of the upper wall portion on the outer peripheral surface side in the radial direction from both ends in the circumferential direction, among the covering portions covering the outer periphery of the winding portion. It is characterized by being formed so as to gradually become thicker toward the center.

  According to a second aspect of the present invention, in the first aspect, the outer peripheral surface of the upper wall portion is an arc surface, and the top portion thereof is ½ of the width of the outermost layer portion in the radial direction of the stator core. It is characterized by being provided at a position.

  According to a third aspect of the present invention, in the first aspect, the stator core is provided with a skew, and the outer peripheral surface of the upper wall portion has an apex at the outermost layer in the radial direction of the stator core. It is characterized in that it is displaced from the position where it becomes 1/2 of the width of the part to the side where the skew is provided.

  According to a fourth aspect of the present invention, in the first, second, or second aspect, the insulator is further characterized in that a portion facing the corners of the upper wall portion and the side wall portion is formed in an arc shape. Yes.

  The manufacturing method according to claim 5 is also included in the present invention. In the method of manufacturing an axial air gap type electric motor, in which the winding portion of the stator core has a plurality of core members covered by an insulator, and each of the core members is annularly arranged around the axis of the rotor output shaft. The insulator is integrally formed on the outer periphery of the insulator core by insert molding by pouring resin in the mold so as to leave the teeth surface of the stator core, and the molten resin is poured into the mold at the time of the insert molding. The position is provided inside the stator core in the radial direction.

  According to the present invention, among the covering surfaces covering the outer periphery of the winding portion, the thickness of the upper wall portion on the radial outer peripheral surface side is gradually increased from the both ends in the circumferential direction toward the center, The stress concentration position on the corner portion of the coil can be shifted from the corner portion of the stator core, and even if there is a burr or the like, the occurrence of cracks in the insulator can be effectively suppressed.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing an axial air gap type electric motor according to an embodiment of the present invention, and FIG. 2 is a front view of a state where stator cores are connected.

  As shown in FIG. 1, this axial air gap type electric motor 1 includes a stator 2 formed in a disk shape, and a pair of rotors 3 that are opposed to each other with a predetermined gap (gap) between both side surfaces of the stator 2. , 3 are provided. The rotors 3 and 3 are coaxially fixed to a rotor output shaft 4 that outputs a rotational driving force.

  Note that the stator 2 and the rotor 3 are housed in a bracket. In this example, the synthetic resin material 6 integrally molded on the outer peripheral surface of the stator 2 also serves as the outer peripheral wall of the bracket, and lid members (not shown) are attached to both ends thereof. In addition, you may make it attach the rotors 3 and 3 directly to a fan etc., without using a cover member.

  In the present invention, the rotors 3 and 3 are arranged on both the left and right sides of the stator 2, but only one of them may be provided. In the present invention, the rotor constitutes the axial air gap type electric motor 1. It suffices if it has the necessary functions, and can be changed arbitrarily according to the specifications.

  A bearing 5 is disposed at the center of the stator 2. In this example, the bearing portion 5 has a pair of radial ball bearings 5 a and 5 b, the inner ring is press-fitted into the rotor output shaft 4, and the outer ring side is a recess formed in the center of the synthetic resin material 6 of the stator 2. Buried. In the present invention, the configuration of the bearing portion 5 may be arbitrary.

  The rotors 3 and 3 share the same rotor output shaft 4, but may be a two-output shaft type in which each rotor 3 and 3 has a rotor output shaft. Furthermore, it is good also as a shaft-less type | mold which does not have the rotor output shaft 4, but supports the rotors 3 and 3 directly with respect to the stator 2 via a radial ball bearing.

  As shown in FIG. 2, the stator 2 includes a plurality (9 (9 slots) in this example) of core members 21a to 21i arranged in an annular shape with the rotation axis of the rotor output shaft 4 as the central axis. Yes. Since the core members 21a to 21i have the same configuration, the core member 21a will be described as an example here.

  Referring also to FIG. 3, the core member 21 a is formed of a laminated body in which a plurality of electromagnetic steel plates formed in an H shape when viewed from the radial direction are laminated along the radial direction. It is formed in a three-dimensional trapezoidal shape in which the width in the circumferential direction gradually increases from the outside toward the outside.

  Thereby, the core member 21a is formed in a bobbin shape having a pair of left and right flange-shaped tooth surfaces 22 and 22, and a coil (not shown) is wound around the winding portion 24 of the stator core 23 formed in the center. Is done.

  The stator core 23 is entirely covered with an insulator 30 made of insulating resin, leaving the tooth surfaces 22 and 22. The insulator 30 includes flange portions 31 and 31 as winding frame plates extending in the radial direction along the tooth surfaces 22 and 22 and a winding covering portion 32 that covers the winding portion 24 of the stator core 23.

  In this example, as shown in FIG. 2, skews inclined at a predetermined angle are formed at both ends of the teeth surface 22 of the stator core 23 in order to reduce cogging torque, as shown in FIG. However, the shape of the tooth surface 22 such as the presence or absence of skew is arbitrarily selected according to the specifications.

  Each flange part 31, 31 is provided with connecting means for connecting the respective pole members 21a to 21i to each other. As connecting means, hook portions 41, 41 for connecting the respective pole members 21 a to 21 i in an annular shape around the axis of the rotor output shaft 4 are provided at one upper end portion in the circumferential direction of the flange portions 31, 31. The other upper end portion is provided with locking shafts 42 and 42 on which the hooks 41 and 41 are locked.

  Moreover, the latching convex part 43 as a connection guide means for connecting each core member 21a-21i more cyclically | annularly is provided in the other lower end part of the circumferential direction of the flange parts 31 and 31, At the other lower end, a locking recess 44 is provided as a receiver side of the locking projection 43.

  The hook portion 41 and the locking shaft 42 as the connecting means, and the locking convex portion 43 and the locking concave portion 44 as the connecting guide means are optional matters in the present invention, and their positions and shapes depend on the specifications. Can be changed arbitrarily.

  As shown in FIG. 4A, the insulator 30 is integrally formed on the outer periphery of the stator core 23 by insert molding in a mold, and the winding covering portion 32 is a winding of the stator core 23. In this example, it is formed in a triangular cross section so as to cover the outer periphery of the portion 24.

  As for this coil | winding coating | coated part 32, it is preferable that the surface facing each corner | angular part 24a-24c of the coil | winding part of the stator core 32 is each chamfered in circular arc shape. According to this, stress concentration can be relieved by winding the coil by fitting it to the corners 24a to 24c.

  Of the winding covering portion 32, the upper wall portion 33 of the outer surface in the radial direction is formed to be thicker than the thicknesses of the other winding covering portions 32, and both end sides in the circumferential direction. It is formed so as to gradually become thicker from the center toward the center.

  According to this, the thickness of the upper wall portion 33 is increased and the thickness increases toward the center, so that vector components F1 and F2 of the winding stress F as shown in FIG. Among them, since the direction of the vector component F1 can be directed to the outer peripheral side, the winding stress F can be reduced and the direction of the winding stress F can be kept away from the corner portion 24a of the winding portion 24 of the stator core 23. Can do.

  By keeping the winding stress F away from the corner portion 24a, the force with which the insulator 30 is pressed against the acute angle portion of the stator core 23 can be reduced. Therefore, it is possible to prevent the insulator 30 from cracking.

  When skew is provided in the stator core 23 as in the present embodiment, as a more preferable aspect, the top portion T has a position that is ½ of the width W and a corner portion on the side where the skew is provided ( In this example, it is preferable that they are arranged so as to be offset from the corners 24a). According to this, it is possible to further reduce the stress related to the acute corner portion 24a on the side where the skew is provided.

  In the present embodiment, the stator core 23 is formed by punching and laminating a plurality of electromagnetic steel sheets in an H shape, and thus it is considered that burrs are generated in the punching direction at the edges of the electromagnetic steel sheets. Even if the insulator 30 is integrally formed with burrs remaining in the core core 23, it is possible to prevent the insulator 30 from being cracked.

  Although not shown, when the stator core 23 is not skewed, the corner portion 24a and the corner portion 24b have the same angle, and therefore the position of the top portion T is the outermost layer in the radial direction of the stator core 23. It is preferable to be provided at a position (W / 2) that is ½ of the width W of the portion.

  In this example, the upper wall portion 33 is formed in an arcuate surface shape, but other than this, a convex portion may be formed, and as shown in FIG. 4B, a part of the upper wall portion 33 is formed. A pair of convex portions 34, 34 may be provided on the same, and the effect of dispersing the winding force of the coil can be obtained in the same manner.

  Here, each convex part 34 and 34 may be arrange | positioned in the position which becomes left-right symmetric across the center of the radial direction outermost layer part of the stator core 23, or may be arrange | positioned in the position which becomes asymmetrical. As a result, the same effect as the arc surface can be obtained.

  By the way, the insulator 30 including the winding covering portion 32 is formed integrally with the stator core 23 by insert molding of resin into a mold. Therefore, in the present invention, it is preferable that the gate position for pouring the molten resin into the mold at the time of insert molding is provided on the inner side in the radial direction of the stator core 23 (the direction opposite to the upper wall portion 33).

  In this example, the gate position is provided from the center near the inner diameter in the radial direction of each flange portion 31, 31 toward the axial direction (in the direction of arrow A1 in FIG. 3), and the molten resin is in the flange portion 31 in the mold. , 31 from the inside to the outside. Note that the gate position is not limited to the flange portion 31, and may be a portion facing the corner portion 24c (arrow A2 in FIG. 3).

  In the winding portion 24, the molten resin first flows so as to cover the corner portion 24 c, and then flows toward the outer peripheral side along the side surface of the winding portion 24. Next, while the molten resin flows along the corners 24a and 24b, the molten resin advances from both sides of the winding part 24 and finally collides and joins near the top part T. Thus, the winding covering portion 32 is formed.

  According to this, since the upper wall part 33 of the coil | winding coating | coated part 32 is thick compared with another part, and it forms in circular arc shape, molten resin fills the inside of a metal mold | die in the stator core 23. As it moves from the inner diameter side toward the outer diameter side, the mold space is wide and the molten resin whose temperature has started to drop can be reliably moved to the outer surface side. And since the junction part of the molten resin divided into two is made into the thickest upper layer part 33 of the coil | winding coating | coated part 32, it can prevent that intensity | strength runs short.

  In this example, the stator core 23 is made of a laminated body of electromagnetic steel sheets, but may be integrally formed by, for example, casting or powder molding, and by adopting the insulator structure of the present invention, the coil The winding force can be effectively dispersed, and as a result, the safety and reliability of the stator 2 are improved.

The schematic diagram of the axial air gap type electric motor concerning one embodiment of the present invention. The front view of the state which connected the stator core cyclically | annularly. The perspective view of the core member which comprises the said stator. (A) The central cross-sectional view of a core member, (b) The central cross-sectional view which shows the modification of an insulator. The schematic diagram which shows the stress dispersion | distribution of the insulator of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Axial air gap type motor 2 Stator 3, 3 Rotor 4 Rotor output shaft 21a-21i Stator core 22 Teeth surface 23 Stator core 24 Winding part 24a-24c Corner | angular part 30 Insulator 31 Flange part 32 Winding coating | cover part 33 Outer peripheral surface 34 Convex

Claims (5)

In an axial air gap type electric motor having a stator in which a winding portion of a stator core has a plurality of core members covered with an insulator, and each of the core members is annularly arranged around the axis of a rotor output shaft.
In the insulator, the thickness of the upper wall portion on the outer peripheral surface side in the radial direction of the covering covering portion covering the outer periphery of the winding portion is gradually increased from both ends in the circumferential direction toward the center. An axial air gap type electric motor characterized by being formed.   2. The axial air according to claim 1, wherein an outer peripheral surface of the upper wall portion is provided at a position where a top portion thereof is ½ of a width of an outermost layer portion in a radial direction of the stator core. Gap type electric motor.   A skew is provided in the stator core, and the outer peripheral surface of the upper wall portion is provided with a skew from a position where the top portion is ½ of the width of the outermost layer portion in the radial direction of the stator core. The axial air gap type electric motor according to claim 1, wherein the axial air gap type electric motor is arranged so as to be shifted to a side where the air gap is provided.   4. The axial air gap type electric motor according to claim 1, wherein the insulator is further formed in an arc shape in a portion facing the corner portions of the upper wall portion and the side wall portion. In the method of manufacturing an axial air gap type electric motor in which the winding portion of the stator core has a plurality of core members covered with an insulator, and each of the core members is annularly arranged around the axis of the rotor output shaft.
The insulator is integrally formed on the outer periphery of the insulator by insert molding by pouring resin in the mold so as to leave the teeth surface of the stator core, and molten resin is poured into the mold at the time of the insert molding. A method for manufacturing an axial air gap type electric motor, wherein a gate position is provided on an inner side in a radial direction of the stator core.

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