JP2009077597A - Motor and method for manufacturing motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve: the problem wherein the increase of the number of rotor poles will lead to reduction in the size of permanent magnets, resulting in a further reduction of insertion workability; and the problem wherein it is necessary to insert at a right angle in order to directly insert a planar permanent magnet into the magnet insertion hole forming a plane, resulting in poor workability because it takes more time for positioning. <P>SOLUTION: A stator and a rotor for rotating relative to the stator are provided. The rotor has a rotor core laminated a magnetic steel sheet and a plurality of permanent magnet pieces aligned around the rotor core. The rotor core has magnet insertion holes aligned around the rotor core, for inserting and holding the permanent insertion holes. The magnetic steel sheet has magnet holding punched holes for forming the magnet insertion holes. One magnetic steel sheet positioned at the end of the rotor is provided with retaining projections of the permanent magnet pieces projecting inward of the magnet holding punched holes to insert the permanent magnet piece using temporary joint retainer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rotor of a brushless electric motor provided with a magnet-embedded rotor, and the manufacture of the rotor.

  As an electric motor provided with a magnet embedded rotor, there is a brushless electric motor. This brushless motor is disclosed in, for example, Patent Document 1 (Japanese Patent Laid-Open No. 2006-320141) and Patent Document 2 (Japanese Patent Laid-Open No. 2004-270544).

  The brushless electric motor is provided such that a plurality of permanent magnet pieces are arranged on the outer peripheral side of the rotor. The permanent magnet piece is inserted and held in a magnet holding hole provided in the rotor core of the rotor, and is placed so as to be embedded in a synthetic resin layer for molding that wraps the rotor core.

JP 2006-320141 A JP 2004-270544 A

  In a magnet-embedded rotor, it is necessary to insert a permanent magnet piece into a predetermined position of a rotor magnet insertion hole. Further, the permanent magnet piece must be embedded in the molding synthetic resin layer while being kept in the predetermined position.

  However, when the number of poles of the rotor is increased, the size of the permanent magnet piece to be handled is reduced, and there is a problem that insertion workability is further deteriorated. Further, in order to insert a flat permanent magnet piece directly into a magnet insertion hole that forms a flat surface, it is necessary to insert it at a right angle, so that it takes time for positioning.

  In view of the above problems, an object of the present invention is to provide an electric motor that is easy to manufacture and assemble and that can insert and embed a permanent magnet piece at a predetermined position.

  The present invention includes a stator and a rotor that rotates with respect to the stator, and the rotor is arranged in a large number on the outer peripheral side of the rotor iron core on which electromagnetic steel plates are laminated and the rotor iron core. There are permanent magnet pieces, the rotor cores are arranged in a large number on the outer peripheral side, have magnet insertion holes for inserting and holding the permanent magnet pieces, and the electromagnetic steel plate has a magnet holding for forming the magnet insertion holes. One of the electromagnetic steel sheets having a punching hole for the rotor and positioned at the end of the rotor is provided with a retaining protrusion for the permanent magnet piece protruding inward of the punching hole for holding the magnet. A permanent magnet piece to be inserted into the magnet insertion hole is held by a retaining protrusion using a holder.

  In the present invention, one electromagnetic steel sheet positioned at the end of the rotor is provided with a retaining protrusion for a permanent magnet piece protruding toward the inside of the magnet holding punching hole, and is provided on the temporary fixing holder. By inserting and holding the permanent magnet piece at a predetermined position of the magnet insertion hole quickly and without displacement through the inclined portion, it is possible to provide an electric motor rotor embedded in the mold synthetic resin layer with good workability.

  Embodiments of the present invention will be described with reference to the drawings.

  First, an outline of a washing and drying machine equipped with the electric motor of the present invention will be described with reference to FIG.

  An outer tub 201 in which washing water accumulates is supported through an anti-vibration mechanism 202 in the outer frame 200 of the washing / drying machine main body. The rotating drum 203 is rotatably placed in the outer tub 201. The brushless electric motor 100 drives the rotary drum 203 to rotate.

  The electric motor 100 is supported on the rear rear surface of the outer tub 201. The rotating drum 203 is directly connected to the electric motor 100 via the rotating shaft 5 and rotates. The electric motor 100 is attached to a metal flange 205 fixed to the outer tub 201.

  At the time of washing, the rotating drum 203 is rotated at a speed of about 40 to 50 RPM, and the laundry 206 in the rotating drum 203 is beaten and washed. At the time of dehydration, it rotates at a high speed of several hundreds of RPM, and the water contained in the laundry 206 is centrifugally dehydrated.

  The washing water used for washing and the washing water subjected to centrifugal dewatering are drained from the drainage channel 207.

  The laundry 206 is dried by a drying ventilation 209 that circulates in the rotary drum 203 through the drying ventilation path 208.

  The brushless electric motor 100 will be described with reference to FIGS.

  First, the outline of the electric motor 100 will be described with reference to FIGS.

  The electric motor 100 includes a rotor 1, a stator 2, a stator base 3, a bearing boss portion 4 having a bearing, and a rotating shaft 5 that is rotatably supported by the bearing and that fixes and supports the rotor 1.

  The stator 2 has a large number of fixed magnetic poles 7 around which a stator coil 6 is wound.

  The rotor 1 has a large number of rotating magnetic poles 8. The rotating magnetic pole 8 faces the inner surface of the fixed magnetic pole 7 and rotates so as to move relative to the fixed magnetic pole 7.

  In the present embodiment, the motor 100 has 42 fixed magnetic poles 7 and the rotor has 56 poles, and a permanent magnet uses a rare earth magnet as a thin, lightweight, high torque motor.

  The rotor 1 will be described with reference to FIGS.

  As shown in FIG. 3, the rotor 1 is mounted on an iron core support base 11 having a support cylindrical portion 10, an annular rotor core 12 fitted to the outer periphery of the support cylindrical portion 10, and the rotor core 12. A plurality of permanent magnet pieces 13, a synthetic resin layer 14 for molding that entirely encloses the rotor core 12, and a boss portion 15 provided in the center.

  As shown in FIGS. 4 and 5, the rotor core 12 is configured as an annular coupling body by connecting divided core portion pieces 16 in which cores are stacked.

  In this embodiment, the rotor core 12 is formed into a ring by connecting seven divided core pieces 16, but the number of divided core pieces 16 can be more or less than this.

  As shown in FIG. 5, the split iron core piece 16 has connecting means at both ends. A circular protrusion connecting portion 17 is provided at one end, and a circular groove connecting portion 18 is provided at the other end. The connecting means is performed by press-fitting the connecting portion 17 of the circular protrusion into the connecting portion 18 of the circular groove.

  The circular projection connecting portion 17 and the circular groove connecting portion 18 of the adjacent divided core portion pieces 16 are connected to each other to form an annular rotor core 12. By connecting the divided core pieces 16 to form the annular rotor core 12, the material yield of the electromagnetic steel plate can be improved and the material used can be reduced as compared with the case of punching out one annular rotor core.

  The annular rotor cores 12 connected in this way are fitted to the support cylindrical portion 10 of the core support base 11 so as to maintain a predetermined circular shape that does not collapse and maintain the mechanical strength in the outer radial direction. Can do.

  The divided core part 16 of the rotor core 12 is a magnetic steel plate including a silicon steel plate and forms a magnetic flux flow path of the electric motor. The electromagnetic steel plates are laminated to a predetermined thickness to form the divided core part pieces 16 which are connected in a ring shape to form the rotor core 12.

  As shown in FIG. 3, the rotor core 12 formed in this way is provided with a number of permanent magnet pieces 13 on the outer peripheral side of the rotor core 12. The permanent magnet piece 13 is inserted and held in a magnet insertion hole 30 provided on the outer peripheral side of the rotor core 12.

  The split iron core piece 16 of the magnetic steel sheet shown in FIG. 6A is a retaining protrusion of the permanent magnet piece 13 protruding inwardly toward the inner peripheral edge of the magnet holding punching hole 31 of the magnet insertion hole 30. 32.

  Only one piece of the split core portion 16 constituting the rotor core 12 is provided at one end to prevent the permanent magnet piece 13 from coming off. However, when the molding pressure acts greatly during molding, a plurality of sheets may be used, but usually one sheet is used to reduce the material cost. On the insertion side of the permanent magnet piece 13, a split iron core piece 16 having no retaining protrusion 32 shown in FIG. 6B is used. The retaining projection 32 has functions of positioning, retaining, and preventing displacement of the permanent magnet piece 13 inserted into the magnet insertion hole 30 in the axial direction. That is, the permanent magnet piece 13 is inserted into the magnet insertion hole 30 from the side without the retaining protrusion 32. When the permanent magnet piece 13 is inserted to the back of the magnet insertion hole 30, it is received by the retaining projection 32 and automatically positioned at a predetermined position.

  The insertion work of the permanent magnet piece 13 does not require adjustment for setting at a predetermined position, so that the assembly work is easy.

  The divided core pieces 16 provided with the retaining protrusions 32 are sufficient to be arranged in a single row, but one or two pieces can be added if necessary. Moreover, it is convenient from the workability | operativity of the permanent magnet piece 13 to provide the division | segmentation iron core part piece 16 with the retaining protrusion 32 in a lower edge part.

  Further, after inserting the permanent magnet piece 13 into the rotor core 12, the rotor core 12 is inserted into a molding die for resin molding, and the above-described molding synthetic resin layer 14 is molded.

  Since the permanent magnet piece 13 is held in a predetermined position by the retaining protrusion 32 even when inserted into the molding die or resin mold, the mold is embedded in the predetermined position without being displaced. Is done.

  Further, the retaining protrusion 32 can be provided so as to protrude inward at the outer peripheral side edge of the magnet holding punching hole 31.

  However, the connecting portions existing on both sides of the magnet holding punching hole 31 are thin and easily bent. This bending deformation shifts the position of the outer peripheral side edge of the magnet holding punching hole 31, so that the retaining protrusion 32 is preferably provided closer to the inner peripheral edge than the outer peripheral edge.

  The rotor core 12 has an envelope portion 33 that surrounds the magnet holding punching hole 31 of the split core portion 16. In the envelope portion 33, the outer envelope portion 33a is separated from the inner envelope portion 33b by a cut and bent portion 33c.

  The separation by the cut and bent portion 33c is performed in a molding die before resin molding. A cutting and bending means is used in the mold, and cutting and bending is performed in a direction crossing the longitudinal direction (insertion direction) of the permanent magnet piece 13. There is no influence of the displacement of the permanent magnet piece 13 due to this. When there is a possibility that the influence of the positional deviation occurs, it is dealt with so that the positional deviation does not occur so as to suppress the permanent magnet piece 13 in advance.

  The outer envelope portion 33a is separated from the inner envelope portion 33b by the cut and bent portion 33c. For this reason, the magnetic flux of the permanent magnet piece 13 does not leak the magnetic flux, unlike the case where the cut portion 33c is not provided, and the performance as an electric motor is improved.

  The separation by the cut and bent portion 33c does not have a problem that chips are attached to the rotor where no chips are generated due to the separation.

  FIG. 7 shows a cross section AA of the part of the retaining protrusion 32 in FIG. The position of the permanent magnet piece 13 is fixed by a retaining protrusion 32. In addition, the envelope portion 33 has two locations on the front and rear surfaces, for a total of four locations. In other parts, space above and below is secured.

  Next, a method for manufacturing the electric motor will be described with reference to FIGS.

  As shown in FIG. 8, the rotor core 12 is fitted to the outer periphery of the support cylindrical portion 10 of the core support base 11.

  As shown in FIG. 10, the rotor core 12 combined with the iron core support base 11 is fitted and attached to the rotor support receiving jig 40 shown in FIG.

  As shown in FIG. 9, the rotor support receiving jig 40 includes an annular fitting groove 41 into which the rotor core 12 and the support cylindrical portion 10 are fitted, and a guide pin insertion hole that penetrates downward from the bottom of the fitting groove 41. 42.

  12 is attached to the lower surface of the rotor support receiving jig 40, as shown in FIG. 12, on the rotor core 12 mounted on the rotor support receiving jig 40. As shown in FIG.

  The guide pin-equipped jig 43 has a guide pin 44, and the guide pin 44 is inserted into the magnet insertion hole 30 from the guide pin insertion hole 42. As shown in FIG. 12, the distal end side of the guide pin 44 passes through the guide pin insertion hole 42 and protrudes above the rotor core 12.

  On this upper side, the temporary fixing holder 45 shown in FIG. 13 is placed as shown in FIG.

  As shown in FIGS. 13, 18, and 19, the temporary fixing holder 45 has a large number of temporary fixing holding through holes 50 arranged in an annular shape. The temporary holding holding through hole 50 is provided so as to coincide with the magnet insertion hole 30 of the rotor core 12. The guide pins 44 of the jig 43 with guide pins are also provided so as to coincide with the magnet insertion holes 30.

  As described above, the temporary fixing holding through hole 50 of the temporary fixing holder 45, the magnet insertion hole 30 of the rotor core 12, and the guide pin 44 of the guide pin-equipped jig 43 are configured to be the same. 44 passes through the magnet insertion hole 30 and is inserted into the through hole 50 for temporary holding.

  Since the guide pin 44 is inserted only to the lower side of the through hole 50 for temporary holding, the most part of the through hole 50 for temporary holding is vacant. The permanent magnet piece 13 is inserted into the vacant temporary holding holding through hole 50 as shown in FIG.

  Thereafter, as shown in FIG. 15, when the guide pin-equipped jig 43 is lowered, the permanent magnet piece 13 is naturally lowered by its own weight and moves from the temporary holding holding through hole 50 to the magnet insertion hole 30.

  Thus, the permanent magnet piece 13 is accommodated in the magnet insertion hole 30 of the rotor core 12 as shown in FIG.

  Thereafter, by removing the rotor support receiving jig 40 from the rotor core 12 side, the rotor core 12 with the permanent magnet pieces 13 inserted as shown in FIG. 17 is completed.

  The corner of the tip is dropped so that the guide pin 44 can be easily inserted into the magnet insertion hole 30 of the rotor core 12. Thereby, the guide pin 44 is easily inserted into the magnet insertion hole 30, and the irregularity of the magnet insertion holes 30 of the laminated core pieces 16 is corrected.

  By this correction, the insertion movement of the permanent magnet piece 13 from the temporary fixing holder 45 to the magnet insertion hole 30 is performed more smoothly.

  In this embodiment, the insertion is performed manually, but it is possible to easily automate the insertion of the permanent magnet piece 13 by connecting a robot, a part feeder or the like.

  The rotor core 12 in which the permanent magnet pieces 13 are inserted is inserted into a mold for molding, and the molding synthetic resin layer 14 described above is molded.

  As described above, the permanent magnet piece 13 naturally descends by its own weight, moves from the temporary holding holding through hole 50 to the magnet insertion hole 30, and fits in the magnet insertion hole 30. Since there is a retaining protrusion 32 projecting inside the lower portion of the magnet insertion hole 30, the permanent magnet piece 13 is kept at a predetermined position and does not fall out of the magnet insertion hole 30.

  Further, even when the mold is inserted into a mold for molding and the molding is performed, the permanent magnet piece 13 is held by the retaining protrusion 32 of the rotor core 12, so that it is not displaced from a predetermined position. And embedded in the molding synthetic resin layer 14.

  The separation of the outer envelope portion 33a and the inner envelope portion 33b by the cutting means described above is performed after the rotor core 12 is transferred to the mold for molding and before molding.

  The insertion of the permanent magnet piece into the temporary holding holding through hole will be described with reference to FIGS.

  The through hole 50 for temporary holding of the temporary holding tool 45 has an inclined portion 46 that expands outward on the upper side (insertion side).

  As shown in FIGS. 20 and 22, the permanent magnet piece 13 inserted into the temporary holding holding through-hole 50 is cut out from a large block. Therefore, in order to reduce the number of processing steps as much as possible, the corners are at right angles. However, it can be smoothly inserted by the inclined portion 46 that extends outward over the entire circumference of the temporary holding holding through hole 50.

  The inclined portion 46 can also be shaped to draw an arc.

  The guide pin 44 of the jig 43 with a guide pin will be described with reference to FIGS.

  The guide pin 44 of the jig 43 with a guide pin is provided with an inclined surface 60 around the tip in order to taper the tip. Since the taper is tapered, the guide pin 44 is smoothly inserted into the guide pin insertion hole 42, the temporary holding holding through hole 50, and the magnet insertion hole 30.

  The guide pin 44 has a relief groove 47 that extends in the insertion / removal direction (longitudinal direction) of the guide pin 44. The escape groove 47 is provided at a position facing the retaining protrusion 32 that projects toward the inside of the magnet insertion hole 30 and has a size that allows the retaining protrusion 32 to be loosely fitted.

  Since the retaining protrusion 32 is loosely fitted in the escape groove 47, the guide pin 44 is smoothly inserted into and withdrawn from the magnet insertion hole 30 even though the guide pin 44 is substantially the same size as the magnet insertion hole 30.

  Since the guide pin 44, the temporary fixing holding through hole 50, and the magnet insertion hole 30 are substantially the same size, the centers of the temporary fixing holding through hole 50 and the magnet insertion hole 30 are aligned. For this reason, the permanent magnet piece 13 is smoothly moved from the temporary fixing holding through hole 50 to the magnet insertion hole 30.

  The permanent magnet piece 13 is magnetized after the permanent magnet piece 13 is moved to the rotor 1. Since the permanent magnet piece 13 is not magnetized before being mounted on the rotor 1, there is no attracting action by magnetic force, and the movement from the temporary holding holding through hole 50 to the magnet insertion hole 30 is easily performed.

  Since the attracting action by the magnetic force does not occur until magnetization is performed, it is necessary to maintain the position of the permanent magnet piece 13 by the retaining protrusion 32.

  Since the rotor core 12 is formed with the magnet insertion holes 30 by four envelope portions 33 in total, one on each of the front and back surfaces, the rotor core 12 is easily deformed.

  For this reason, in order to insert directly by hand, insertion becomes difficult due to deformation of the insertion surface of the permanent magnet piece 13. By correcting this with the guide pins 44, insertion can be facilitated.

  Further, since the guide pin 44 is provided with the relief groove 47 of the retaining projection 32 at one part of a part of the wide surface, all the four surfaces can be brought into contact with the surface of the magnet insertion hole 30 for correction. Can be improved.

  Further, the sectional area of the escape groove 47 can be small because it only prevents the permanent magnet piece 13 from coming off, and the rigidity of the guide pin 44 is sufficiently ensured.

The front view of the electric motor according to the embodiment of the present invention. The longitudinal cross-sectional view of an electric motor which concerns on the Example of this invention. The longitudinal cross-sectional view of a rotor which concerns on the Example of this invention. The front view of the rotor core according to the embodiment of the present invention. The front view of the division | segmentation iron core part piece based on the Example of this invention. The enlarged view of the division | segmentation iron core part piece based on the Example of this invention. The cross-sectional enlarged view of the division | segmentation iron core part piece which concerns on the Example of this invention and has a retaining protrusion in a magnet insertion hole. It is a figure which concerns on the Example of this invention, and is a figure which shows the state which fitted the rotor core to the outer periphery of the support cylindrical part of an iron core support base | substrate. The figure which concerns on the Example of this invention and shows a rotor support receiving jig. The figure which concerns on the Example of this invention and shows the state which mounted | wore the rotor support receiving jig with the rotor core. The figure which concerns on the Example of this invention and shows a jig | tool with a guide pin. The figure which concerns on the Example of this invention and shows the state which mounted | wore the lower surface of the rotor support receiving jig with the jig | tool with a guide pin. The figure which concerns on the Example of this invention and shows a temporary fixing holder. The figure which concerns on the Example of this invention and shows the state which mounted the temporary fixing holder on the upper side of the rotor core. It is a figure which concerns on the Example of this invention, showed the place which moves a permanent magnet piece from a through hole for temporary holding to a magnet insertion hole by lowering | hanging a jig | tool with a guide pin. The figure which concerns on the Example of this invention, and shows the place which finished moving the permanent magnet piece from the through hole for temporary holding to a magnet holding hole. The figure which concerns on the Example of this invention and shows the state which removed the rotor support receiving jig from the iron core support base | substrate which has a rotor iron core. The front view of the temporary fixing holder according to the embodiment of the present invention. The vertical cross-sectional view of a temporary fixing holder according to the embodiment of the present invention. The figure which concerns on the Example of this invention and shows a permanent magnet piece. The expanded sectional view of the through-hole for temporary holding | maintenance concerning the Example of this invention. The expanded sectional view which concerns on the Example of this invention, and the permanent magnet piece was inserted in the through-hole for temporary fixing holding | maintenance. The enlarged view which concerns on the Example of this invention and expanded and showed the guide pin of the jig | tool with a guide pin. The figure which concerns on the Example of this invention and looked at the guide pin from the front end side. The figure which concerns on the Example of this invention, and looked at the guide pin from the direction with a relief groove. The vertical cross section of the washing-drying machine which concerns on the Example of this invention and mounted the electric motor in the washing-drying machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotor 2 Stator 10 Supporting cylindrical part 11 Iron core support base 12 Rotor core 13 Permanent magnet piece 16 Split iron core piece 30 Magnet insertion hole 31 Magnet holding hole 32 Retaining protrusion 33 Enveloping part 33a Outer envelope part 33b Inside Envelope portion 33c Cutting / bending part 40 Rotor support receiving jig 43 Jig 44 with guide pin Guide pin 45 Temporary holding tool 47 Escape groove 50 Through hole for temporary holding

Claims (13)

A stator and a rotor that rotates relative to the stator;
The rotor has a rotor core in which electromagnetic steel sheets are laminated, and permanent magnet pieces arranged in a large number on the outer peripheral side of the rotor core,
The rotor core is arranged in a large number on the outer peripheral side, and has a magnet insertion hole for holding the permanent magnet piece,
The electromagnetic steel sheet has a magnet holding punching hole for forming the magnet insertion hole,
The electric motor according to claim 1, wherein one of the electromagnetic steel sheets positioned at an end of the rotor is provided with a retaining protrusion for the permanent magnet piece projecting inward of the magnet holding punching hole. The electric motor according to claim 1, wherein
The electric motor according to claim 1, wherein the retaining protrusion is provided on an inner peripheral edge of the magnet holding punching hole. A stator and a rotor that rotates relative to the stator;
The rotor includes a core support base having a support cylindrical portion, an annular rotor core formed by laminating electromagnetic steel plates supported on the outer periphery of the support cylindrical portion, and a large number on the outer peripheral side of the rotor core. Having permanent magnet pieces arranged,
The rotor core is arranged in a large number on the outer peripheral side, and has a magnet insertion hole for holding the permanent magnet piece,
The electromagnetic steel sheet has a magnet holding punching hole for forming the magnet insertion hole,
The electric motor according to claim 1, wherein one of the electromagnetic steel sheets positioned at an end of the rotor is provided with a retaining protrusion for the permanent magnet piece projecting inward of the magnet holding punching hole. The electric motor according to claim 3, wherein
The rotor core has a plurality of divided core pieces connected in a ring shape. The electric motor according to claim 4, wherein
The electric motor according to claim 1, wherein the divided iron core piece is provided with coupling means connected to both ends. The electric motor according to claim 1 or 4,
The rotor core has an envelope surrounding the magnet holding punching hole,
An electric motor, wherein an outer envelope portion of the envelope portion is separated from an inner envelope portion by a cutting and bending position. A stator and a rotor that rotates relative to the stator;
The rotor includes a core support base having a support cylindrical portion, an annular rotor core formed by laminating electromagnetic steel plates supported on the outer periphery of the support cylindrical portion, and a large number on the outer peripheral side of the rotor core. Having permanent magnet pieces arranged,
The rotor core is arranged in a large number on the outer peripheral side, and has a magnet insertion hole for holding the permanent magnet piece,
The electromagnetic steel sheet has a magnet holding punching hole for forming the magnet insertion hole,
The rotor is loaded into a rotor support receiving jig,
The rotor loaded in the rotor support receiving jig is combined with the jig with guide pin so that the guide pin of the jig with guide pin is inserted into the magnet holding punching hole from below.
A temporary fixing holding jig for temporarily holding the permanent magnet piece is combined so as to match the upper side of the rotor,
A method of manufacturing an electric motor, wherein the permanent magnet piece is moved from the temporary holding jig to the magnet insertion hole by separating the jig with guide pins from the rotor. In the manufacturing method of the electric motor according to claim 7,
A method of manufacturing an electric motor, wherein the permanent magnet piece is magnetized after the permanent magnet piece is transferred to the magnet insertion hole. In the manufacturing method of the electric motor according to claim 7,
The method of manufacturing an electric motor according to claim 1, wherein the movement of the permanent magnet piece from the temporary holding jig to the magnet insertion hole is due to natural fall. In the manufacturing method of the electric motor according to claim 7,
The method of manufacturing an electric motor according to claim 1, wherein one of the electromagnetic steel sheets positioned at an end of the rotor is provided with a retaining projection for the permanent magnet piece projecting inside a magnet holding punching hole. In the manufacturing method of the electric motor according to claim 7,
The temporary holding jig has a temporary holding holding through hole for temporarily holding the permanent magnet piece,
The method of manufacturing an electric motor, wherein the temporary holding holding through hole has a shape in which an insertion side into which the permanent magnet piece is inserted expands outward. In the manufacturing method of the electric motor according to claim 10,
The method for manufacturing an electric motor according to claim 1, wherein the guide pin has an escape groove extending along a guide pin insertion / removal direction at a position where the retaining projections face each other. In the manufacturing method of the electric motor according to claim 7,
The rotor core has an envelope surrounding the magnet holding punching hole,
A method for manufacturing an electric motor, comprising: separating the outer envelope portion of the envelope portion from the inner envelope portion at a bending position after the permanent magnet piece is transferred from the temporary holding jig to the magnet insertion hole.

Images