JP2012205443A - Electric motor and method for manufacturing electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric motor that allows magnets of neodymium-based magnetic material to be bonded to respective inner surfaces of peripheral walls of a yoke without being displaced, detached, or broken.SOLUTION: An electric motor includes: a cylindrical yoke 5 that is formed with a polygonal cross section and has a plurality of flat walls 61; a plurality of flat plate-like magnets 7 of neodymium-based magnetic material that are fixed to respective inner surfaces 61a of the flat walls 61 with an instant adhesive 25; and an armature 6 that is rotatably supported on a radially inner side of the magnets 7.

Description

  The present invention relates to an electric motor mounted on a vehicle, for example, and a method for manufacturing the electric motor.

  2. Description of the Related Art Conventionally, as an electric motor, for example, an electric motor with a brush in which a plurality of magnets are arranged on the inner peripheral surface of a yoke and an armature is rotatably provided radially inward of the magnet is known. The armature includes an armature core that is externally fixed to a rotating shaft, and a commutator in which a plurality of segments are disposed. The armature core is provided with a plurality of teeth extending radially outward, and a plurality of axially long slots are formed between the teeth. Windings are inserted through these slots, and windings are wound around each tooth by concentrated winding or distributed winding.

The winding is in conduction with the commutator segment. Each segment is in sliding contact with a brush for supplying power, and current is supplied to the winding through this brush.
When a current is supplied to the winding, a magnetic field is formed, and the armature is rotated by a magnetic attractive force or a repulsive force generated between the magnetic field and the magnet.

Here, many methods for fixing a magnet to the inner peripheral surface of the yoke have been proposed. For example, in Patent Document 1, the outer peripheral surface of a magnet formed in a substantially U shape in the axial direction is fixed to the inner peripheral surface of the sub yoke formed in a substantially C shape in the axial direction by an adhesive. . The sub-yoke to which the magnet is fixed is fitted and fixed to the inner peripheral surface of the bottomed cylindrical main yoke. In this way, the magnet is fixed to the inner peripheral surface of the yoke.
In general, a one-pack epoxy adhesive is used as an adhesive for fixing the magnet. This epoxy adhesive is cured by drying for several hours in a drying oven at a high temperature of about 120 ° C to 150 ° C.

  In recent years, it has been desired to reduce the size and improve the performance of the electric motor configured as described above. Therefore, an electric motor using a magnet (hereinafter referred to as a neodymium magnet) made of a neodymium-based magnetic material such as NdFeB (neodymium-iron-boron) has been proposed. As described above, by using a neodymium magnet having a strong magnetic force, an attempt is made to reduce the size and performance of an electric motor.

  By the way, the neodymium magnet has a characteristic that the thermal expansion coefficient differs between the magnetization direction and the non-magnetization direction. Specifically, in the magnetization direction, the thermal expansion coefficient of the neodymium magnet has a positive value, and, like a general metal, etc., it expands by heating and contracts by cooling. On the other hand, in the non-magnetization direction, the thermal expansion coefficient of the neodymium magnet has a negative value, and unlike general metals, it contracts by heating and expands by cooling.

JP 2001-309586 A

Here, when the above-mentioned neodymium magnet is applied to the electric motor of Patent Document 1, there are the following problems.
FIG. 5 is an explanatory diagram when the above-described neodymium magnet 107 is applied to the electric motor of Patent Document 1. In FIG. In FIG. 5, the magnetization direction of the neodymium magnet 107 is the radial direction of the yoke 105, and the non-magnetization direction of the neodymium magnet 107 is the circumferential direction of the yoke 105. In order to make the problem easy to understand, a case where the sub-yoke is omitted and the neodymium magnet 107 is bonded to the yoke 105 will be described.

  In the magnet adhering step of adhering the neodymium magnet 107 to the inner peripheral surface 105a of the yoke 105, the neodymium magnet 107 is attached to the yoke 105 via an epoxy adhesive and then put into a drying furnace at a high temperature. At this time, since the viscosity of the epoxy adhesive temporarily decreases due to heating, the neodymium magnet 107 may slip, and the yoke 105 may be displaced from the fixed position.

  Further, when the neodymium magnet 107 is bonded to the yoke 105 and then cooled, the yoke 105 has a positive coefficient of thermal expansion, so that the yoke 105 contracts in the circumferential direction and shrinks in diameter due to cooling. In contrast, the neodymium magnet 107 expands in the circumferential direction, which is a non-magnetization direction, and contracts in the radial direction, which is a magnetization direction, by cooling. In this way, when a temperature change occurs, bending stress acts on the neodymium magnet 107 along the radial direction due to the reduced diameter of the yoke 105 and the expanded diameter of the neodymium magnet 107, so that the neodymium magnet 107 is peeled off from the yoke 105. In addition, the neodymium magnet 107 may break.

  Therefore, an object of the present invention is to provide an electric motor and a method for manufacturing the electric motor that can adhere a magnet made of a neodymium-based magnetic material to the inner surface of the peripheral wall of the yoke without causing displacement or peeling and cracking of the magnet.

  In order to solve the above-described problems, an electric motor according to a first aspect of the present invention includes a cylindrical yoke formed in a polygonal cross section and having a plurality of flat walls, and an instantaneous adhesive on the inner surface of each flat wall. It is characterized by comprising a plurality of fixed plate-shaped magnets made of rare earth, and an armature that is rotatably supported radially inward of the magnets.

According to the present invention, since the magnet is bonded to the yoke by the instantaneous adhesive, it can be bonded in a short time without heating at room temperature. Therefore, compared with the case where it adheres with the conventional epoxy adhesive which consists of 1 liquid, generation | occurrence | production of the shift | offset | difference of the magnet resulting from the viscosity fall of the adhesive agent at the time of a heating can be prevented.
In addition, the magnet made of neodymium magnetic material has a flat plate shape and is bonded to the flat wall of the yoke formed in a polygonal shape, so even if temperature changes, bending stress is applied to the magnet along the radial direction. Does not occur. Therefore, it can suppress that the magnet which consists of a neodymium type magnetic material peels from a yoke by a temperature change.
Further, since the flat magnet is bonded to the flat wall of the yoke, the bonding area can be secured more stably over the entire surface than when the curved surfaces are bonded. Therefore, stable adhesive strength can be ensured.

The electric motor according to claim 2 of the present invention is characterized in that the magnet is made of a neodymium-based magnetic material.
According to the present invention, a magnet made of a neodymium magnetic material can be particularly preferably used.

The electric motor according to claim 3 of the present invention is characterized in that the instantaneous adhesive is cured by mixing a first liquid composed of an adhesive solvent and a second liquid composed of a curing agent.
According to the present invention, since a two-component instantaneous adhesive that cures by mixing a first liquid composed of an adhesive solvent and a second liquid composed of a curing agent is used, it is dried at a high temperature. It can be bonded in a short time by chemical reaction. Thereby, generation | occurrence | production of the shift | offset | difference of the magnet resulting from the viscosity fall of the adhesive agent at the time of a heating can be prevented reliably.

The electric motor according to claim 4 of the present invention is characterized in that the instantaneous adhesive is an acrylic instantaneous adhesive in which the first liquid is made of an acrylic resin.
Acrylic adhesives have good adhesion to nickel, which is often used for plating magnets made of neodymium magnetic materials. According to the present invention, since the instantaneous adhesive is an acrylic instantaneous adhesive, it can be suitably used for a magnet made of a neodymium magnetic material plated with nickel.

According to a fifth aspect of the present invention, there is provided a method for manufacturing an electric motor, comprising: a magnet bonding step of bonding the magnet to the inner surface of each flat wall with the instantaneous adhesive; A liquid having a higher viscosity of the liquid and the second liquid is applied to the magnet, while a liquid having a lower viscosity of the first liquid and the second liquid is applied to the inner surface of the yoke. .
According to the present invention, since the low viscosity liquid is applied to the inner surface of the yoke, compared to the case where the high viscosity liquid is applied to the inner surface of the yoke, It can be applied easily and evenly by spraying. Thereby, the adhesion surface of a magnet and a yoke can fully be secured and it can fix firmly.

According to the present invention, since the magnet is bonded to the yoke by the instantaneous adhesive, it can be bonded in a short time without heating at room temperature. Therefore, compared with the case where it adheres with the conventional epoxy adhesive which consists of 1 liquid, generation | occurrence | production of the shift | offset | difference of the magnet resulting from the viscosity fall of the adhesive agent at the time of a heating can be prevented.
In addition, the magnet made of neodymium magnetic material has a flat plate shape and is bonded to the flat wall of the yoke formed in a polygonal shape, so even if temperature changes, bending stress is applied to the magnet along the radial direction. Does not occur. Therefore, it can suppress that the magnet which consists of a neodymium type magnetic material peels from a yoke by a temperature change.
Further, since the flat magnet is bonded to the flat wall of the yoke, the bonding area can be secured more stably over the entire surface than when the curved surfaces are bonded. Therefore, stable adhesive strength can be ensured.

It is a fragmentary sectional view of an electric motor. It is a disassembled perspective view of an electric motor. It is sectional drawing in the AA of FIG. It is explanatory drawing of a magnet adhesion process. It is explanatory drawing when a neodymium magnet is applied to the electric motor of patent document 1. FIG.

Below, the electric motor 1 of this embodiment is demonstrated using drawing.
FIG. 1 is a partial cross-sectional view of the electric motor 1.
The electric motor 1 shown in FIG. 1 is used as a drive motor for a vehicle power window, sunroof, electric seat, wiper device, and the like.

  As shown in FIG. 1, the electric motor 1 has a brush holder housing in which an armature 6 is rotatably provided in a cylindrical portion 53 of a yoke 5 via a motor rotating shaft 3 and is formed on an opening edge 53 b of the cylindrical portion 53. The brush holder unit 20 that accommodates the brush 30 (see FIG. 1) is fitted and fixed to the portion 90.

(yoke)
FIG. 2 is an exploded perspective view of the electric motor 1.
3 is a cross-sectional view taken along line AA in FIG. In FIG. 3, the thickness of the magnet 7 and the instantaneous adhesive 25 described later are exaggerated for easy understanding of the drawing. Further, only the yoke 5, the magnet 7 and the armature core 8 are illustrated, and the illustration of the armature coil 16a, the insulator 14 and the like (see FIG. 2) is omitted.
As shown in FIG. 2, the yoke 5 is a bottomed cylindrical member made of a metal such as iron, and is molded by pressing or the like by deep drawing.
As shown in FIG. 3, the cylindrical portion 53 occupying most of the yoke 5 has an inner peripheral wall 53a formed in a substantially hexagonal shape in the axial plan view, and has a diameter across the central axis O in the axial plan view. It has six flat walls 61 that face each other in the direction, and six corner portions 63 that connect the flat walls 61. The flat walls 61 and the corner parts 63 are alternately arranged along the circumferential direction, and the flat walls 61 and the corner parts 63 are arranged to face each other.

The separation distance between the opposing flat walls 61 is set to be slightly larger than the dimension obtained by adding the thickness dimension of the magnet 7 to be described later to the diameter of the armature 6 disposed in the cylindrical portion 53.
The corner portion 63 is formed in a substantially arc shape when viewed in the axial direction, and connects the circumferential end portions of the adjacent flat walls 61 so as to straddle between the six adjacent flat walls 61.

  As shown in FIG. 1, a boss 19 that protrudes outward along the central axis O is formed at the approximate center of the bottom wall 51 of the yoke 5. A bearing 18 made of an annular metal or the like is press-fitted and fixed to the inner peripheral surface of the boss 19. One end side (right side in FIG. 1) of the motor rotating shaft 3 is pivotally supported by a boss 19 of the yoke 5 via a bearing 18.

  A thrust plate 54 is provided at the bottom of the boss 19. The thrust plate 54 receives the thrust load of the motor rotating shaft 3 via the steel balls 55. The steel ball 55 reduces the sliding resistance between the motor rotating shaft 3 and the thrust plate 54 and absorbs the misalignment of the motor rotating shaft 3.

  A brush holder accommodating portion 90 is integrally formed on the cylindrical portion 53 of the yoke 5 on the opening edge 53b side (left side in FIG. 1). The housing wall 90a of the brush holder housing 90 is for housing the brush holder unit 20 described later. The housing wall 90a of the brush holder housing 90 is formed in an approximately oval shape in an axial plan view, and one radial direction (the left-right direction in FIG. 2) is the longitudinal direction, and the other radial direction ( The vertical direction in FIG. 2 is the short direction.

  As shown in FIG. 2, the accommodating wall 90 a of the brush holder accommodating portion 90 is formed so as to straddle the pair of accommodating flat portions 91 having a plane opposed in the short direction and the pair of accommodating flat portions 91. And a pair of arcuate portions 92 that connect the circumferential ends of the accommodation flat surface portions 91 that face each other in the longitudinal direction. A brush holder unit 20 (described later) is fitted and fixed to the brush holder housing 90 by press fitting or the like.

As shown in FIG. 1, an outer flange 52 for fixing the electric motor 1 to an external device is provided on the housing wall 90 a on the brush holder housing 90 side. The external device includes, for example, a speed reduction mechanism (not shown) that houses a worm gear and a worm wheel.
A plurality of bolt holes 52a (three in this embodiment) are formed in the outer flange portion 52, bolts (not shown) are inserted, and the electric motor 1 is fastened and fixed to an external device.

(Armature)
As shown in FIG. 2, the armature 6 rotatably provided in the cylindrical portion 53 of the yoke 5 includes an armature core 8 that is externally fitted and fixed to the motor rotating shaft 3, and an armature coil that is wound around the armature core 8. 16 a and a commutator 10 disposed on the other end side of the motor rotating shaft 3. The armature core 8 is formed by laminating a plurality of ring-shaped magnetic plates 11 made of electromagnetic steel plates or the like in the axial direction.

  On the outer periphery of the magnetic plate 11, nine teeth 12 formed in a substantially T shape in an axial plan view are arranged radially at equal intervals along the circumferential direction. The tip end portion of the tooth 12 extends along the circumferential direction and forms the outer peripheral portion of the armature core 8.

  A groove-shaped slot 13 extending along the axial direction is formed on the outer periphery of the armature core 8. The slot 13 is formed by externally fixing a plurality of magnetic plates 11 to the motor rotating shaft 3, and is formed between the outer peripheral portions of adjacent teeth 12. Since the number of teeth is nine as described above, nine slots 13 between the teeth 12 are also formed. In addition, since the teeth 12 are arranged at equal intervals along the circumferential direction, a plurality of slots 13 are also formed at equal intervals along the circumferential direction.

  Furthermore, an insulating insulator 14 is attached to the tooth 12. Then, for example, an enamel-wrapped winding 16 is inserted between the slots 13, and the winding 16 is wound on the teeth 12 from above the insulator 14. As a result, a plurality of armature coils 16 a are formed on the outer periphery of the armature core 8.

  As shown in FIG. 1, nine segments 15 made of a conductive material are attached to the outer peripheral surface of the commutator 10 that is fitted and fixed to the other end side (left side in FIG. 1) of the motor rotating shaft 3. . The segment 15 is formed of a plate-shaped metal piece that is long in the axial direction. The segments 15 are fixed in parallel at equal intervals along the circumferential direction in a state of being insulated from each other.

  A riser (not shown) that is folded in an outwardly folded manner is integrally formed at the end of each segment 15 on the armature core 8 side. A winding 16 of an armature coil 16a is wound around the riser, and the winding 16 is fixed to the riser by, for example, fusing. Thereby, the segment 15 and the armature coil 16a corresponding to this are conducted.

  The segment 15 is in sliding contact with a brush 30 (see FIG. 3) for supplying electric power to the segment 15. Here, the brush 30 is provided in the brush holder unit 20 housed in the housing wall 90 a of the brush holder housing 90.

(Brush holder unit)
The brush holder unit 20 includes a brush holder 22 constituting a main body portion, a spring 21 that urges the brush 30, a noise prevention element (not shown) that suppresses noise, and a bus bar (not shown) that electrically connects each component. Etc.
The brush holder 22 is a member made of a resin or the like, which is formed in a substantially oval shape in a plan view in the axial direction. On the first surface F of the brush holder 22, a brush 30, a spring 21, a noise prevention element and the like are arranged.
A through hole 22a penetrating the first surface F and the second surface S of the brush holder 22 is formed in the approximate center of the brush holder 22, and a slide bearing 40 is press-fitted into the through hole 22a. The motor rotating shaft 3 is inserted into the slide bearing 40, and the load generated by the sliding resistance is suppressed to a minimum so that it can be efficiently rotated.

  The brush 30 accommodated in the brush holder 22 is a member formed in a substantially rectangular parallelepiped shape made of a conductive material such as carbon. Two brushes 30 are provided in the brush holder 22, one being an anode brush and the other being a cathode brush. The pair of brushes 30 are arranged so that the longitudinal direction of the brushes 30 is along the straight line L in a state where the mechanical angles are spaced apart in the circumferential direction by 180 °. The brush 30 is in contact with the segment 15 of the commutator 10 by the biasing force of the spring 21 and supplies power to the armature 6.

(magnet)
As shown in FIGS. 2 and 3, six magnets 7 are provided on the inner peripheral wall 53 a of the cylindrical portion 53 of the yoke 5. Specifically, the magnets 7 are provided one by one on the inner surfaces 61 a of the six flat walls 61 formed in the cylindrical portion 53 of the yoke 5.
The magnet 7 is a rare earth magnet made of a neodymium-based magnetic material, and is formed into a flat plate shape by a bond manufacturing method in which it is mixed with an adhesive material such as sintering or an epoxy-based resin and then molded and solidified. The surface of the magnet 7 is plated with a metal such as nickel to prevent rust and the like.
The axial length of the magnet 7 is set to be substantially the same as or slightly shorter than the axial length of the cylindrical portion 53 of the yoke 5. The circumferential width of the magnet 7 is set to be slightly smaller than the circumferential width of the inner surface 61 a of the flat wall 61.

  The magnet 7 is magnetized along the thickness direction of the magnet 7. That is, when the magnet 7 is attached to the cylindrical portion 53 of the yoke 5, N-pole and S-pole magnetic poles are formed along the radial direction of the cylindrical portion 53.

  The six magnets 7 are attached so that the N-pole and S-pole magnetic poles alternate along the circumferential direction. The six magnets 7 are arranged so that the N pole and the S pole are opposed to each other. The pitch angle between adjacent magnets 7 is set to be about 60 °. That is, the electric motor 1 constitutes a three-pole pair (six-pole) motor.

The magnets 7 are each affixed to the inner surface 61 a of the flat wall 61 using the instantaneous adhesive 25.
The instantaneous adhesive 25 is, for example, a two-component instantaneous adhesive 25. The first liquid 25a (see FIG. 4) made of an adhesive solvent such as an acrylic resin and the second liquid 25b made of a curing agent (see FIG. 4). ) And are cured. The time required for curing the instantaneous adhesive 25 is about 100 seconds to 180 seconds at room temperature.
In general, the instantaneous adhesive 25 made of an acrylic resin adheres well to nickel. Therefore, the instantaneous adhesive 25 made of acrylic resin is suitably used for the magnet 7 of this embodiment that has been plated with nickel.

(Magnet bonding process)
FIG. 4 is an explanatory diagram of a magnet bonding process.
As shown in FIG. 4, the method for manufacturing the electric motor 1 according to this embodiment includes a magnet bonding step of bonding the magnet 7 to the inner surface 61 a of the flat wall 61 with the instantaneous adhesive 25.
In the magnet bonding process, first, of the two liquids constituting the instantaneous adhesive 25, a liquid having a high viscosity is applied to the sticking surface of the magnet 7, while a liquid having a low viscosity is applied to the inner peripheral wall 53a of the yoke 5. ing. In the present embodiment, the viscosity of the first liquid 25a made of an adhesive solvent such as an acrylic resin is high, and the viscosity of the second liquid 25b made of a curing agent is low. Therefore, the first liquid 25 a is applied to the sticking surface of the magnet 7, and the second liquid 25 b is applied to the entire inner peripheral wall 53 a of the yoke 5.

  Here, since the bonding surface on the yoke 5 side is the inner surface 61a of the flat wall 61 of the inner peripheral wall 53a of the yoke 5, the second liquid 25b may be applied only to the inner surface 61a of the flat wall 61. However, since the yoke 5 is formed in a cylindrical shape, it is difficult to apply the second liquid 25b only to the inner surface 61a of the flat wall 61. Therefore, the second liquid 25b is applied to the entire inner peripheral wall 53a of the yoke 5 by using, for example, a spray. In this way, a liquid having a low viscosity is applied to the inner peripheral wall 53a of the yoke 5 by spraying or the like, so that it can be applied easily and uniformly.

  Subsequently, the adhesive surface of each magnet 7 coated with the first liquid 25a and the flat wall 61 of the yoke 5 coated with the second liquid 25b are overlapped to attach the magnet 7 to the flat wall 61 of the yoke 5. Affix it. Then, while holding the magnet 7 outwardly in the radial direction of the yoke 5 using a jig (not shown), it is held for a predetermined time (for example, about 100 seconds to 180 seconds). Thus, the first liquid 25a and the second liquid 25b are mixed and chemically reacted to be cured, and the magnet 7 is bonded to the inner surface 61a of each flat wall 61.

(effect)
According to this embodiment, since the magnet 7 is bonded to the yoke 5 by the instantaneous adhesive 25, it can be bonded in a short time without heating at normal temperature. Therefore, compared with the case where it adheres with the conventional epoxy adhesive which consists of 1 liquid, generation | occurrence | production of the shift | offset | difference of the magnet 7 resulting from the viscosity fall of the adhesive at the time of a heating can be prevented.
Further, the magnet 7 made of neodymium-based magnetic material has a flat plate shape and is adhered to the flat wall 61 of the yoke 5 formed in a polygonal shape. A bending stress is not generated in the magnet 7 along the line. Therefore, it can suppress that the magnet 7 which consists of a neodymium type magnetic material peels from the yoke 5 by a temperature change, or is cracked.
Furthermore, since the flat-plate-shaped magnet 7 is bonded to the flat wall 61 of the yoke 5, it is possible to ensure a stable bonding area over the entire surface, compared to the case where the curved surfaces are bonded to each other. Therefore, stable adhesive strength can be ensured.

  Further, according to the present embodiment, since the two-component instantaneous adhesive 25 that is cured by mixing the first liquid 25a made of the adhesive solvent and the second liquid 25b made of the curing agent is used, It can be bonded in a short time by chemical reaction without drying at high temperature. Thereby, generation | occurrence | production of the shift | offset | difference of the magnet 7 resulting from the viscosity fall of the adhesive agent at the time of a heating can be prevented reliably.

  By the way, the acrylic adhesive has good adhesion with nickel, which is often used for plating the magnet 7 made of a neodymium magnetic material. According to the present embodiment, since the instantaneous adhesive 25 is an acrylic instantaneous adhesive, it can be suitably used for the magnet 7 made of a neodymium magnetic material plated with nickel.

  In addition, according to the present embodiment, since the liquid having a low viscosity is applied to the inner peripheral wall 53a of the yoke 5, the liquid having a high viscosity is formed in a cylindrical shape as compared with the case where the liquid having a high viscosity is applied to the inner peripheral wall 53a of the yoke 5. It can be easily and evenly applied to the inner peripheral wall 53a of the formed yoke 5 by spraying or the like. As a result, a sufficient adhesion surface between the magnet 7 and the yoke 5 can be secured, so that the magnet 7 can be firmly fixed.

The present invention is not limited to the embodiment described above.
In the present embodiment, it has been described that the electric motor 1 is used for driving at least one of a power window, a sunroof, an electric seat, and a wiper device of a vehicle, for example. However, the use of the electric motor 1 is not limited to these, and can be applied to various devices such as an electric power steering of a vehicle and an electrical component other than the vehicle.
In addition, it has been described that the connection destination of the electric motor 1 is a speed reduction mechanism including a worm gear. However, the connection destination of the electric motor 1 is not limited to the speed reduction mechanism, and may be connected to an actuator mechanism other than the speed reduction mechanism or another external device.

  In the present embodiment, the 6-pole 9-slot 9-segment electric motor 1 has been described as an example. However, the number of poles, the number of slots, the number of segments, and the like of the electric motor 1 are not limited to this embodiment. Further, the cross-sectional shape of the cylindrical portion 53 of the yoke 5 is not limited to the substantially hexagonal shape of the present embodiment.

  In the present embodiment, the magnet 7 made of a neodymium magnetic material has been described as an example. However, even if the magnet 7 is other than a neodymium-based magnetic material, the present invention can be used if the magnet 7 has a positive thermal expansion coefficient in the magnetization direction and a negative thermal expansion coefficient in the non-magnetization direction. Applicable. Specifically, the magnet 7 may be a samarium cobalt magnet mainly composed of samarium and cobalt.

DESCRIPTION OF SYMBOLS 1 ... Electric motor 5 ... Yoke 6 ... Armature 7 ... Magnet 25 ... Instant adhesive 25a ... 1st liquid 25b ... 2nd liquid 61 ... Flat wall 61a ..Inner surface

Claims (5)

A cylindrical yoke having a polygonal cross section and having a plurality of flat walls;
A plurality of plate-shaped magnets made of rare earth, fixed to the inner surface of each flat wall by an instantaneous adhesive,
An armature that is rotatably supported radially inward of the magnet;
An electric motor comprising:   The electric motor according to claim 1, wherein the magnet is made of a neodymium magnetic material.   The electric motor according to claim 1, wherein the instantaneous adhesive is cured by mixing a first liquid made of an adhesive solvent and a second liquid made of a curing agent.   The electric motor according to claim 3, wherein the instantaneous adhesive is an acrylic instantaneous adhesive in which the first liquid is made of an acrylic resin. It is a manufacturing method of the electric motor of Claim 3 or 4,
A magnet bonding step of bonding the magnet with the instantaneous adhesive on the inner surface of each flat wall;
The magnet bonding process includes
Applying a high viscosity liquid of the first liquid and the second liquid to the magnet, while applying a low viscosity liquid of the first liquid and the second liquid to the inner surface of the yoke. A method of manufacturing an electric motor characterized by

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