JP2005261136A - Electric motor and electric power steering apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric motor for reducing and inhibiting a magnetic loss and easily assembled. <P>SOLUTION: The electric motor 1 comprises a stator core 22 and a plurality of teeth 27 bonded to an inner circumference 31 of an annular yoke 28. A gap 39 between bonded faces 35, 34 of the teeth 27 and the yoke 28 is filled with a resin composition 44 comprising a synthetic resin J1 containing a magnetic filler J2. A rotor 19 comprises an annular rotor core 26 and a ring magnet 25. An outer circumference 46 of the annular rotor core 26 is bonded to an inner circumference 45 of the ring magnet 25. Since a gap 47 between the inner and outer circumferences 45, 46 is filled with the resin composition 44, the magnetic loss can be reduced. A resin composition 48 containing a high permeability filler J3 can be used. Since fitting of the bonded faces 34, 35 or the inner and outer circumferences 45, 46 can be mitigated and a work skill is not required during assembly, the electric motor 1 including the stator core 22 and the rotor 19 can be easily assembled. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electric motor and an electric power steering apparatus including the same.

Some electric motors include a rotor that is rotatably supported by a housing, and a stator that faces the outer periphery of the rotor and is fixed to the housing.
Some stators have a stator core in which a plurality of teeth extend radially inward from an annular yoke and a coil wound around the teeth of the stator core. The stator core has an annular outer core that forms a yoke, and an inner core that is formed separately from the outer core to form a plurality of teeth and the inner peripheral portions of the teeth are connected to each other. The inner core is joined (see Patent Documents 1 and 2). For example, in the stator core of Patent Document 2, the outer periphery of the inner core is joined to the inner periphery of the outer core by shrink fitting.

Further, the inner periphery of the ring magnet is fitted into the outer periphery of the cylindrical rotor core, and a buffering adhesive, for example, a room temperature curing type, is provided in the gap between the engagement surfaces of the rotor core and the ring magnet. There is a rotor filled with an epoxy adhesive, an anaerobic room temperature curable adhesive, an ultraviolet curable adhesive, and the like (see Patent Document 3).
JP 2002-142391 A JP-A-9-84282 Japanese Patent Laid-Open No. 9-93845

Patent Document 1 does not specifically describe the joining between the inner core and the outer core. However, if there is a gap between the outer peripheral surface of the inner core and the inner peripheral surface of the outer core, this gap is the cause. As a result, magnetic loss increases. Conversely, in order to eliminate the gap, it is conceivable to press-fit the inner core into the outer core. In this case, the fitting between the joint surfaces is tight, and it is difficult to assemble the stator core.
Moreover, in the stator core of patent document 2, since the inner core is shrink-fitted into the outer core, skill is required for work, and it is difficult to assemble the stator core.

Moreover, in the rotor of the electric motor of Patent Document 3, an adhesive is filled in the gap between the outer periphery of the rotor core and the inner periphery of the ring magnet. This adhesive is for buffering, and the magnetic properties of the adhesive Is not considered at all, and is equivalent to the magnetic characteristics of a standard adhesive resin material, and the magnetic loss of the rotor increases due to the gap.
Further, in an electric power steering apparatus such as an automobile to which the electric motor is applied, and other industrial machines, there is a demand for suppression of magnetic loss of the electric motor.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an electric motor that can suppress magnetic loss and can be easily assembled, and an electric power steering apparatus using the electric motor.

  The electric motor of the present invention is a motor having a stator core formed by joining a plurality of teeth to the inner peripheral surface of an annular yoke, and a synthetic resin with a high permeability filler in a gap between the joint surfaces of the teeth and the yoke. And a resin composition containing at least one of magnetic fillers. According to this invention, the magnetic flux can easily pass between the joining surfaces, so that the magnetic loss can be suppressed small. As a result, for example, the magnetic flux density of the stator core is increased, and the output of the electric motor can be increased. Moreover, since the fitting between the joint surfaces can be loosened at the time of assembly and no skill is required for the work, the stator core and thus the electric motor can be easily assembled.

  Further, the electric motor of the present invention is an electric motor having a rotor in which a ring magnet is joined to the outer peripheral surface of an annular rotor core, and the synthetic resin is highly permeable in a gap between the ring magnet and the rotor core fitting surface. A resin composition containing at least one of a magnetic filler and a magnetic filler is filled. According to the present invention, the magnetic flux easily passes between the fitting surfaces, so that the magnetic loss can be suppressed to be small. For example, the magnetic flux density at the rotor is increased, and the output of the electric motor can be increased. Moreover, since the fitting between the fitting surfaces can be loosened at the time of assembly, and skill is not required for the work, the rotor and thus the electric motor can be easily assembled.

In the present invention, the resin composition may contain an adhesive. In this case, the joining surfaces of the teeth and the yoke or the fitting surfaces of the ring magnet and the rotor core can be joined together by adhesion.
The electric power steering apparatus according to the present invention includes a steering mechanism that steers the steered wheels by a steering torque loaded on a steering member, and the above-described electric motor according to the present invention that generates a steering assist force according to the steering torque. The steering assist is performed by applying a steering assist force from the electric motor to the steering mechanism. According to the present invention, the steering assist force from the high-output electric motor can be quickly transmitted to the steering mechanism during steering. In addition, the electric motor and thus the electric power steering device can be downsized or made inexpensive.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic diagram illustrating a schematic configuration of an electric power steering apparatus including an electric motor according to an embodiment of the present invention.
In the present embodiment, the case where the electric motor 1 is applied to the electric power steering apparatus 2 will be described. However, the electric motor 1 can also be applied to industrial machines other than the electric power steering apparatus 2.

The electric power steering device 2 includes a steering mechanism 5 that steers the steered wheels 4 by a steering torque loaded on a steering wheel 3 as a steering member, and an electric motor 1 that generates a steering assist force according to the steering torque. I have. Steering assistance can be performed by applying a steering assist force from the electric motor 1 to the steering mechanism 5.
The steering mechanism 5 includes a steering shaft 6 that transmits a steering torque applied to the steering wheel 3 to steer the steering wheel 4, and a steering column 7 that rotatably supports the steering shaft 6 through the inside. Have. A steering wheel 3 is connected to one end 6 a of the steering shaft 6. A steering mechanism 9 for steering the steering wheel 4 is connected to the other end 6b of the steering shaft 6 via an intermediate shaft 8 or the like so as to be interlocked.

The steering mechanism 9 includes a pinion 10 connected to the steering shaft 6 and a rack shaft 11 that meshes with the pinion 10. The steering wheel 4 is connected to the end of the rack shaft 11 so as to be steerable.
When the steering wheel 3 is steered, the steering torque is transmitted to the steering mechanism 9 via the steering shaft 6 and the like, so that the steering wheel 4 can be steered.

  In addition, the electric power steering apparatus 2 can obtain a steering assist force that is commensurate with the steering resistance that occurs with the steering operation. That is, the electric power steering apparatus 2 is provided in association with the steering shaft 6 and based on a torque sensor 12 for detecting steering torque, an output signal from the torque sensor 12, a vehicle speed signal from a vehicle speed sensor (not shown), and the like. The electric motor 1 that generates the steering assist force, the speed reducer 14 for decelerating the rotation of the output shaft 13 of the electric motor 1, the speed reducer 14 and the torque sensor 12 are accommodated and supported, and the electric motor 1 and a control unit 16 including a microcomputer for controlling the driving of the electric motor 1.

The housing 15 forms a part of the steering column 7. The reducer 14 has a worm shaft as a drive gear and a worm wheel as a reduction gear driven by the worm shaft. The worm shaft is driven by the electric motor 1. A worm wheel is coupled to the steering shaft 6 so as to be rotatable together.
When the steering wheel 3 is operated, the steering torque is detected by the torque sensor 12, and the electric motor 1 generates a steering assist force according to the torque detection result and the vehicle speed detection result. The steering assist force is transmitted to the steering shaft 6 via the speed reducer 14, and is transmitted to the steering mechanism 9 along with the movement of the steering wheel 3, so that the steered wheel 4 is steered.

Referring to FIGS. 1 and 2, an electric motor 1 includes a casing 17 as a fixing member that is supported by a housing 15 and formed in a cylindrical shape, and a plurality of bearings (not shown) in the casing 17. It has an output shaft 13 that is rotatably supported, a stator 18 that surrounds the output shaft 13 and has an annular shape, and a rotor 19 that is locked so as to rotate integrally with the output shaft 13.
The electric motor 1 is a brushless DC motor, and the stator 18 has a coil 20 for excitation. In order to control the energization of the coil 20 by the control unit 16, at least one position sensor 21 that detects the rotational angle position of the rotor 19 with respect to the stator 18 is provided.

  Referring to FIG. 2, the stator 18 includes a stator core 22 supported and locked by the casing 17, and a plurality of coils 20 for forming magnetic poles on the stator core 22. The stator core 22 has a cylindrical shape surrounding the rotor 19 and is disposed concentrically with the output shaft 13. By energizing the predetermined coil 20 in a predetermined direction, an N-pole or S-pole magnetic pole is formed on the inner peripheral surface 23 of the stator core 22 corresponding to the coil 20.

  The rotor 19 has a cylindrical shape and is arranged concentrically with the output shaft 13. The outer peripheral surface 24 of the rotor 19 faces the inner peripheral surface 23 of the stator core 22 via a gap. The rotor 19 includes a cylindrical ring magnet 25 and a cylindrical rotor core 26 interposed between the ring magnet 25 and the output shaft 13. The outer peripheral surface 24 of the rotor 19 is formed by the outer peripheral surface of the ring magnet 25 and has a plurality of magnetic poles. The plurality of magnetic poles include N and S poles. N-pole magnetic poles and S-pole magnetic poles are alternately arranged in the circumferential direction, and are arranged uniformly in the circumferential direction.

Referring to FIG. 3, the stator core 22 includes a plurality of, for example, twelve teeth 27 that are evenly arranged in the circumferential direction, and an annular yoke 28 as an outer core that surrounds the plurality of teeth 27 from the radially outer side. Yes.
A plurality of slots 29 are formed in the stator core 22. Each slot 29 is surrounded and partitioned by two teeth 27 adjacent to each other and an arcuate portion 28 a of a yoke 28 that connects the two teeth 27.

  The plurality of teeth 27 are integrally formed to constitute an integrally formed product 30 as an inner core. The integrally formed product 30 is formed separately from the yoke 28. Specifically, the plurality of teeth 27 are integrally formed of laminated steel plates. This laminated steel sheet is formed by laminating a plurality of annular plates formed by punching electromagnetic steel sheets. As the electromagnetic steel plate, for example, a surface-insulated silicon steel plate or the like can be used. The yoke 28 is formed of laminated steel plates with the same number of layers as the teeth 27. The stator core 22 is formed by joining an integrally formed product 30 including a plurality of teeth 27 to an inner peripheral surface 31 of an annular yoke 28.

The teeth 27 include a main body portion 32 extending along the radial direction, and a pair of extending portions 33 provided at end portions 27a on the radially inner side of the teeth 27 and extending in opposite directions in the circumferential direction. .
A thin portion is provided at the extending end of the extending portion 33. The radially outer portion of the thin portion is recessed. The extending portions 33 of the two adjacent teeth 27 are connected to each other through the thin portion. Thus, the stator core 22 is formed in a closed slot type that closes the slot 29 with respect to the rotor 19. Further, the inner peripheral surface 23 of the stator core 22 is formed in a circumferential endless cylindrical surface by a plurality of teeth 27.

With reference to FIGS. 2 and 3, the main portions 32 of the plurality of teeth 27 are arranged radially about the rotation center position of the output shaft 13. A coil 20 that passes through the slot 29 is wound around each main body 32. A radially outer end 27 b of each tooth 27 is engaged with and joined to the inner peripheral surface 31 of the yoke 28.
Thus, by forming the stator core 22 in a closed slot type, the occurrence of torque unevenness can be suppressed. Moreover, the radially outer ends 27 b of the plurality of teeth 27 are joined to the inner peripheral surface 31 of the yoke 28. Since the slot 29 can be opened radially outward before joining, the coil 20 can be easily passed through the opened slot 29 from the outside in the radial direction, and the coil 20 can be easily attached to the tooth 27.

  A plurality of joining surfaces 34 are provided on the inner peripheral surface 31 of the yoke 28 for joining to the radially outer ends 27b of the plurality of teeth 27, respectively. The plurality of joint surfaces 34 of these yokes 28 are formed in the same manner. Corresponding to this joint surface 34, a joint surface 35 is provided at the radially outer end 27 b of each tooth 27. The joint surfaces 35 of the plurality of teeth 27 are formed in the same manner. Below, it demonstrates centering on the one joint surface 34 of the yoke 28, and the joint surface 35 of the one teeth 27 corresponding to this.

Referring to FIG. 4, the joint surface 34 of the yoke 28 is formed in a concave portion as a undulating portion. An end portion 27b of the tooth 27 is fitted into the recess. The recess is formed between two protrusions 36 that protrude inward in the radial direction and are spaced apart from each other in the circumferential direction. Two protrusions 36 sandwich the end portion 27b of the tooth 28 from both sides.
The joint surface 34 of the yoke 28 is in contact with the joint surface 35 of the corresponding tooth 27, and the first and second restricting portions 37 and 38 that position the tooth 27 in both directions in the circumferential direction are joined to the corresponding tooth 27. It includes a facing portion 40 that faces the surface 35 in the radial direction with a gap 39 interposed therebetween. About the some joint surface 34, the 1st and 2nd control parts 37 and 38 are formed in the laminated steel plate as a common member, and are positioned with high precision mutually.

The joint surface 35 of the tooth 27 is formed on an end portion 27 b having a convex shape as a undulating portion that engages with the above-described concave portion of the yoke 28.
The joint surface 35 of the tooth 27 is positioned by contacting the first and second restricting portions 37 and 38 of the joint surface 34 of the yoke 28 so as to face each other in the circumferential direction. 42, and a facing portion 40 of the joint surface 34 of the yoke 28 and a facing portion 43 that is opposed to each other in the radial direction through a gap 39.

In the present embodiment, a gap 39 between the joint surface 35 of the tooth 27 and the joint surface 34 of the yoke 28 is filled with a resin composition 44 containing the synthetic resin J1 and the magnetic filler J2. The synthetic resin of the resin composition 44 contains an adhesive. Thereby, the resin composition 44 has connected the joining surfaces 34 and 35 so that relative movement is impossible.
As the adhesive, for example, a room temperature curable adhesive such as a room temperature curable epoxy adhesive, an anaerobic room temperature curable adhesive, or a light curable adhesive may be used.

The magnetic filler includes a ferromagnetic material, and specifically iron powder or the like can be used.
The content ratio of the magnetic filler in the resin composition 44 is determined based on the adhesive strength of the resin composition 44, the torque of the electric motor 1, the safety factor, and the like.
Referring to FIG. 5, the rotor 19 is formed by joining the inner peripheral surface 45 of the ring magnet 25 to the outer peripheral surface 46 of the annular rotor core 26. The entire area of the inner peripheral surface 45 of the ring magnet 25 is fitted in a gap-fitting state opposite to the entire area of the outer peripheral surface 46 of the rotor core 26 in the radial direction. The inner peripheral surface 45 and the outer peripheral surface 46 are fitted together. It corresponds to the surface. A gap 47 is provided between both the fitting surfaces. The gap 47 is formed with a predetermined width in the radial direction and surrounds the outer peripheral surface 46 of the rotor core 26 in an annular shape. The gap 47 is filled with the resin composition 44 described above. The resin composition 44 connects the fitting surfaces so as to be integrally rotatable.

  With reference to FIG. 4, in the present embodiment, a resin in which a magnetic filler is contained in a synthetic resin in a gap 39 between the joint surface 35 of the teeth 27 of the stator core 22 of the electric motor 1 and the joint surface 34 of the yoke 28. Filled with composition 44. Thereby, the magnetic filler is magnetized, and the magnetic flux easily passes between the joint surfaces 34 and 35, so that the magnetic loss can be suppressed to a small value. As a result, for example, the magnetic flux density of the stator core 22 is increased, and the output of the electric motor 1 can be increased. Moreover, since the fitting between the joint surfaces 34 and 35 can be loosened during assembly and no skill is required for the work, the stator core 22 and thus the electric motor 1 can be easily assembled. In order to obtain this effect, it is sufficient that the gap 39 is filled with a resin composition containing a synthetic resin and at least one of a highly magnetic filler and a magnetic filler as described later.

  With reference to FIG. 5, in this embodiment, a resin composition 44 is filled in a gap 47 between the inner peripheral surface 45 of the ring magnet 25 of the rotor 19 of the electric motor 1 and the outer peripheral surface 46 of the rotor core 26. . Thereby, the magnetic flux easily passes between the inner peripheral surface 45 and the outer peripheral surface 46, so that the magnetic loss can be reduced. For example, the magnetic flux density in the rotor 19 is increased, and the output of the electric motor 1 can be increased. Moreover, since the fitting between the inner peripheral surface 45 and the outer peripheral surface 46 can be loosened during assembly and no skill is required for the work, the rotor 19 and thus the electric motor 1 can be easily assembled. In order to obtain this effect, it is only necessary to fill the gap 47 with a resin composition containing a synthetic resin and at least one of a highly magnetic filler and a magnetic filler, as will be described later.

4 and 5, since resin composition 44 contains an adhesive, bonding surface 35 of teeth 27 and bonding surface 34 of yoke 28 or inner peripheral surface 45 of ring magnet 25 and rotor core are used. 26 can be joined to each other by adhesion. Therefore, it is possible to dispense with the use of a joining structure other than an adhesive.
The filling method of the resin composition 44 is not particularly limited. For example, when the stator core 22 is assembled and the teeth 27 and the yoke 28 are assembled, the resin composition 44 is formed in the gap 39 formed between the joining surfaces 34 and 35. May be injected. Alternatively, the tooth 27 and the yoke 28 may be assembled in a state where the resin composition 44 is applied to at least one of the joining surfaces 34 and 35. In the rotor 19, the resin composition 44 may be injected into the gap 47 after the ring magnet 25 is fitted to the rotor core 26. Alternatively, the ring magnet 25 may be fitted to the rotor core 26 with the resin composition 44 applied to at least one of the inner peripheral surface 45 of the ring magnet 25 and the outer peripheral surface 46 of the rotor core 26. The resin composition 44 is solidified while being filled in the gaps 39 and 47.

Since the yoke 28 and the tooth 27 are loosely fitted in the axial direction, the layers of the tooth 27 and the yoke 28 formed of laminated steel plates can be easily aligned with each other, and an increase in magnetic loss is easily suppressed. can do.
Referring to FIG. 1, the electric power steering apparatus 2 is a steering mechanism 5 that steers a steered wheel 4 by a steering torque loaded on a steering member. The steering generated by the electric motor 1 according to the steering torque. Steering assistance is performed by applying an assisting force. Thereby, the steering assist force from the high-output electric motor 1 can be quickly transmitted to the steering mechanism 5 at the time of steering. In addition, the electric motor 1 and thus the electric power steering device 2 can be downsized or made inexpensive.

Thus, the electric motor 1 can obtain a large torque output, and the closed slot type stator core 22 can reduce the cogging torque to obtain a rotation with small torque unevenness.
Therefore, in the electric power steering device 2, it is possible to speed up the start-up of the operation of the steering wheel 4 by using the large torque of the electric motor 1. For example, it is possible to realize a sharp steering by generating a sufficient steering assist force following the driver's sudden steering operation. Therefore, the steering feeling can be enhanced.

Since a large torque is obtained, the reduction ratio of the speed reducer 14 can be reduced, or the speed reducer 14 can be omitted. Also in this respect, the rising operation at the time of steering of the steering wheel 4 can be accelerated. Therefore, the steering assist force can be obtained in a short time from the stop state of the electric motor 1, and the steering feeling can be further enhanced.
Further, since the torque unevenness can be reduced, unnatural fluctuations in the steering assist force from the electric motor 1, and consequently fluctuations in the reaction force during the steering that the driver receives can be suppressed. Therefore, the steering feeling can be further increased.

Moreover, the following modifications can be considered about this embodiment. In the following description, differences from the above-described embodiment will be mainly described, and in the case of illustration, the same components will be denoted by the same reference numerals and description thereof will be omitted.
For example, with reference to FIG. 4 and FIG. 6, in the above-mentioned embodiment, although the resin composition 44 contained the magnetic filler J2 in the synthetic resin J1, it is not limited to this. For example, as the resin composition, a resin composition 48 containing a highly permeable filler J3 in the synthetic resin J1 instead of the magnetic filler J2 may be used.

  The high magnetic permeability filler J3 contributes to the improvement of the magnetic properties of the resin composition 48, that is, the magnetic permeability, and the magnetic flux easily passes through the resin composition 48. As the high magnetic permeability filler J3, if the value of the relative magnetic permeability exceeds the value of the resin composition (1 for epoxy resin), the magnetic permeability can be substantially increased. For example, the relative magnetic permeability Cobalt having a value of 250, nickel having a relative permeability of 600, iron having a relative permeability of 5000, and silicon steel having a relative permeability of 7000 can be used. Cobalt, nickel, iron, and silicon steel are readily available and practically preferred. Of these, it is more preferable that the material having iron as a main component is used as the highly permeable filler J3 because it is inexpensive.

The content ratio of the highly magnetic filler J3 in the resin composition 48 is determined based on the adhesive strength of the resin composition 44, the torque of the electric motor 1, the safety factor, and the like.
Further, the high permeability filler J3 and the magnetic filler J2 may be used in combination, and at least one of the high permeability filler J3 and the magnetic filler J2 is filled with a resin composition contained in the synthetic resin J1. If there is. In the following modification examples, the resin composition 48 can be used instead of the resin composition 44 or in addition to the resin composition 44.

In the above-described embodiment, a room-temperature curable adhesive is used as the adhesive, but the present invention is not limited to this. For example, as the adhesive, it is conceivable to use a thermosetting adhesive that is accompanied by heating of the adhesive during bonding.
Moreover, in the above-mentioned embodiment, although synthetic resin was an adhesive agent, it is not limited to this. For example, each of the above resin compositions may include a synthetic resin obtained by mixing a synthetic resin as an adhesive and a synthetic resin that does not function as an adhesive. Further, for example, a structure in which the joint surfaces 34 and 35 of the stator core 22 are connected so as not to move relative to each other, and a structure in which the fitting surfaces of the rotor 19 are connected so as to be integrally rotatable can be used in addition to the above resin compositions. If it is provided separately, it may be possible to eliminate the adhesive.

In the above-described embodiment, the same type of resin composition 44 is used for the rotor 19 and the stator core 22. However, the present invention is not limited to this, and a plurality of resins having different compositions depending on the rotor 19 and the stator core 22. A composition may be used. It is also conceivable that only one of the rotor 19 and the stator core 22 is filled with the above-described resin compositions.
In the above-described embodiment, the joint surface 34 of the yoke 28 is a concave portion and the joint surface 35 of the tooth 27 is a convex portion, but the present invention is not limited to this. For example, the joint surface 34 of the yoke 28 may be a convex portion as the undulating portion, and the joint surface 35 of the tooth 27 may be a concave portion as the undulating portion. It is also conceivable that the first and second restricting portions 37 and 38 and the first and second restricted portions 41 and 42 may be eliminated.

In the above-described embodiment, the stator core 22 is a closed slot type. However, the stator core 22 is not limited to this. For example, the stator core 22 may be an open slot type in which the slot is open to the rotor. In this case, the stator core is formed by joining a plurality of teeth formed separately from each other to the inner peripheral surface of the annular yoke.
Moreover, in the above-mentioned embodiment, although the electric motor 1 was a brushless DC motor, it is not limited to this. The structure of the above-described embodiment is a ring of an external field type electric motor such as an induction motor, a synchronous motor, an SR motor (switched reluctance motor) having a similar stator structure, or a synchronous motor having a similar rotor structure. It can be applied to an electric motor using a type magnet.

  In the above-described embodiment, the electric motor 1 is applied to the column-type electric power steering device 2 provided in the steering column 7 in order to obtain the steering assist force according to the steering torque. However, the present invention is not limited to this. . For example, the electric motor 1 is a power steering device in which an electric motor for generating a steering assist force is provided in a steering mechanism, or a so-called steer-by-steer where mechanical connection between the steering shaft and the steering mechanism is released. -You may apply to a wire (SBW) apparatus. Moreover, you may apply the electric motor 1 to various general industrial machines other than a motor vehicle. In addition, various design changes can be made within the scope of matters described in the claims.

It is a mimetic diagram of a schematic structure of an electric power steering device of one embodiment of the present invention. It is sectional drawing of the electric motor of FIG. It is an expanded sectional view of the stator core of the electric motor of FIG. FIG. 4 is an enlarged view of a joint surface of the stator core in FIG. 3 and the vicinity thereof, and a schematic diagram of a resin composition is illustrated in a circle. It is sectional drawing of the rotor of the electric motor of FIG. It is a schematic diagram of the modification of a resin composition.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric motor 2 Electric power steering apparatus 3 Steering wheel (steering member)
4 Steering Wheel 5 Steering Mechanism 19 Rotor 22 Stator Core 25 Ring Magnet 26 Rotor Core 27 Teeth 28 Yoke 31 Inner Peripheral Surface 34 (Yoke) Joint Surface 35 (Yose) Joint Surface 39, 47 Clearance 44, 48 Resin Composition 46 Outer peripheral surface (fitting surface)
45 Inner peripheral surface (fitting surface)
J1 Synthetic resin (adhesive)
J2 Magnetic filler J3 High permeability filler

Claims (4)

  In the electric motor having a stator core formed by joining a plurality of teeth to the inner peripheral surface of the annular yoke, at least one of a highly permeable filler and a magnetic filler is added to the synthetic resin in a gap between the joint surfaces of the teeth and the yoke. An electric motor characterized by being filled with a contained resin composition.   In an electric motor having a rotor in which a ring magnet is joined to an outer peripheral surface of an annular rotor core, at least one of a high-permeability filler and a magnetic filler is added to a synthetic resin in a gap between the ring magnet and the fitting surface of the rotor core. An electric motor characterized by being filled with a contained resin composition.   3. The electric motor according to claim 1, wherein the resin composition includes an adhesive. A steering mechanism for steering the steering wheel by a steering torque loaded on the steering member;
An electric motor according to any one of claims 1 to 3, which generates a steering assist force according to a steering torque,
An electric power steering apparatus characterized in that steering assist is performed by applying a steering assist force from an electric motor to a steering mechanism.

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