JP2011188697A - Motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent deterioration in efficiency of a motor or an increase in temperature of a motor shaft by preventing the occurrence of an eddy current of the motor shaft due to variation in magnetic flux in using a magnetic body to form the motor shaft and utilizing it as a part of a magnetic path. <P>SOLUTION: A conductor part 7a for shielding conduction for a variation of magnetic flux to the motor shaft 2 and a high-permeability low-loss electromagnetic member 8a for forming a bypass magnetic path for the variation which is shielded by the conductor part 7a are provided on the outside of the motor shaft 2. The occurrence of the eddy current of the motor shaft 2 is prevented by the shielding of the conductor part 7a, and the component of variation (ripples) in magnetic flux is made to pass through the bypass magnetic path of the low-loss electromagnetic member 8a to prevent deterioration in efficiency of the axial gap motor 1 or the increase in temperature of the motor shaft 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a motor having a magnetic path configuration in which a magnetic flux between a stator and a rotor passes through a motor shaft of a magnetic material in an axial direction, and more specifically, generation of eddy current due to pulsation (variation) of magnetic flux passing through a motor shaft is prevented. Concerning structure.

  Conventionally, a radial gap motor has been proposed as a motor in which a part of a magnetic path of a magnetic flux between a stator and a rotor is formed by a magnetic motor shaft (see, for example, Patent Document 1).

  FIG. 8 shows a radial gap (outer stator) motor (hybrid excitation motor) 100 described in Patent Document 1, and a stator (armature) 101 of the motor 100 winds a coil (armature winding) 103 around an iron core 102. This is the structure. The iron core 102 has an N pole side iron core 102a on one side in the motor axis direction and an S pole side iron core 102b on the other side, and a ring-shaped DC exciting winding 105 is provided between the iron cores 102a and 102b. ing.

  A rotor (rotor) 111 inside the stator 101 has an iron core 112 and an N pole, S pole PM (permanent magnet) 113, and the iron core 112 is connected to a motor shaft (shaft) 115, a yoke 114, That is, it is supported by a yoke 114 that is a part of the motor shaft 115. The iron core 112 forms a plurality of poles (salient pole portions) 112 a, and each pole 112 a is provided corresponding to the iron cores 102 a and 102 b of the stator 101. As a result, the rotor 111 has a structure in which the poles 112a and 112b and the PM 113 are alternately arranged in the circumferential direction.

  When a current flows through the excitation winding 105, a closed magnetic circuit including the yoke 114 is formed as indicated by the solid line in FIG. 8, and the magnetic flux between the stator 101 and the rotor 111 passes through this closed magnetic circuit.

  On the other hand, the applicant of the present application has already filed an axial gap motor having a three-dimensional magnetic path configuration as this type of axial gap motor (Japanese Patent Application No. 2009-0115232).

  FIG. 9 is a schematic exploded perspective view of a three-phase drive axial gap motor 200 of the applicant's previously filed application. The motor 200 includes two motor shafts that are axially supported by a motor shaft (not shown). A single stator 204 having magnetic pole faces on both sides is provided between the rotors 203a and 203b, and a cylindrical magnetic path forming member 205 attached to the motor shaft is loosely inserted into the center hole of the stator 204, thereby magnetic path forming member 205. Are formed in contact with the end surfaces (magnetic pole surfaces) of the rotors 203a and 203b. The magnetic path forming member 205 forms a magnetic path between the rotors 203a and 203b. In addition, the solid line m of FIG. 10 shows a motor shaft, and the broken line arrow shows the magnetic path through which magnetic flux passes.

  In the rotors 203a and 203b, for example, eight rotor magnetic poles 206 are arranged at equal intervals in the circumferential direction on the end face (magnetic pole face) facing the stator 204. In the stator 4, for example, twelve stator magnetic poles 207 a in the phase order of A, B, and C, which are excited to the S poles, are arranged at equal intervals in the circumferential direction on one end face (magnetic pole face) facing the rotor 203 a. The 12 stator magnetic poles 207b having the phase sequence of A, B, and C that are all excited to the N pole on the other end face (magnetic pole face) facing the rotor 203b are shifted from the stator magnetic pole 207a in the circumferential direction at equal intervals. It is arranged.

  In the axial gap motor 200, the excitation coils (not shown) concentratedly wound around the stator magnetic poles 207a and 207b of the stator 204 by three-phase driving are energized in the order of phases A, B, and C. 5, a solid magnetic path is formed in which the magnetic flux travels in the axial direction and the circumferential direction of the stator 204 as indicated by broken line arrows. For example, when the magnetic flux emitted from the N pole of the excitation phase on the back surface of the stator 204 passes through the three-dimensional magnetic path, the excitation phase S on the surface of the stator 204 passes through the rotor 203b, the magnetic path forming member 205, and the rotor 203a. The rotor 203a, 203b is rotated by the magnetic attraction and the axial gap motor 200 is driven.

JP-A-6-351206

  The motor 100 of the conventional example of FIG. 8 can adjust the field magnetic flux of the motor 100 by adjusting the magnetic flux generated by the field winding 105 to the magnetic flux of PM 113. When the magnetic flux passing through the motor shaft 115 formed of a solid magnetic material such as carbon steel fluctuates due to a change in magnetic resistance caused by the rotation of the motor 100, an eddy current is generated in the motor shaft 115 to cause a loss. .

  This loss causes a reduction in the output efficiency of the motor 100, and also acts as a braking force (brake) on the motor 100, so that the shaft torque of the motor 100 decreases. Further, the temperature of the motor shaft 115 is increased.

  In the motor 200 of the already-filed application in FIG. 9, when the motor shaft is formed of a magnetic material and the magnetic path forming member 205 is omitted, the magnetic flux passes through the motor shaft. Also in this case, if the magnetic flux passing through the motor shaft formed of the solid magnetic material fluctuates due to a transient current change or a magnetoresistive change due to the rotation of the motor 200, an eddy current is generated in the motor shaft. Loss is caused, the torque (shaft torque) of the motor 200 is lowered, the efficiency is lowered, and further, the temperature of the motor shaft is increased.

  The present invention prevents the generation of eddy currents in the motor shaft due to fluctuations in magnetic flux when the motor shaft is formed of a magnetic material and used as a part of a magnetic path regardless of whether it is an axial gap motor or a radial gap motor. The purpose is to prevent a decrease in efficiency and a temperature rise of the motor shaft.

  In order to achieve the above object, the motor of the present invention is a motor having a magnetic path configuration in which the magnetic flux between the stator and the rotor passes through the magnetic motor shaft in the axial direction. It is characterized by comprising: a conductor part that shields fluctuations from flowing into the motor shaft; and a high-permeability low-loss electromagnetic member part that forms a bypass magnetic path shielded by the conductor parts. (Claim 1).

  In the motor of the present invention, the conductor portion is formed by a coil body having an 8-shaped coil structure having an inner diameter side loop and an outer diameter side loop outside the inner loop, and the inner diameter side loop surrounds the motor shaft, The outer diameter side loop surrounds the conductor portion (claim 2).

  In the case of the motor of the present invention according to claim 1, when the magnetic flux flowing into the motor shaft of the magnetic material fluctuates (pulsates), a loop current is generated in the conductor due to the fluctuation, and the reverse magnetic flux based on the current causes The fluctuation of the magnetic flux flowing into the motor shaft is canceled and the fluctuation of the magnetic flux is shielded. Therefore, generation of eddy current in the motor shaft due to the fluctuation can be prevented.

  Furthermore, if the fluctuation (pulsation) component of the magnetic flux is only shielded by the conductor part, the magnetic flux passing through the motor shaft is smoothed, so that it is impossible to generate torque that should be generated when the magnetic flux increases. In the case of the invention, the low loss electromagnetic member outside the motor shaft forms a bypass magnetic path corresponding to the fluctuation (pulsation) of the magnetic flux, and the fluctuation of the magnetic flux passes through the bypass magnetic path of the low loss electromagnetic member having a high permeability. It is used for driving the motor, and the torque of the motor does not drop. And a low-loss electromagnetic member with a high magnetic permeability does not cause a temperature rise due to fluctuations.

  Therefore, when the motor shaft is formed of a magnetic material and used as a part of a magnetic path, generation of eddy currents in the motor shaft due to fluctuations in magnetic flux can be prevented to prevent a decrease in efficiency and a temperature increase of the motor shaft. And a motor with excellent characteristics can be provided.

  In the case of the motor according to the second aspect of the present invention, the low-loss electromagnetic member has an inner loop on the inner diameter side of the coil body of the 8-shaped coil structure forming the conductor portion, and the magnetic flux passing through the motor shaft varies ( Pulsating), an induction current (loop current) of linkage flux based on the fluctuation of the magnetic flux flows through the inner diameter side loop and the outer diameter side loop, and the magnetic flux flowing into the motor shaft by the magnetic flux of the inner diameter side loop generated by the induction current. Is used as a magnetomotive force for guiding the magnetic flux to the bypass magnetic path of the low-loss electromagnetic member by flowing the induced current through the outer diameter side loop.

  Therefore, when the motor shaft is made of a magnetic material and used as part of the magnetic path, generation of eddy currents in the motor shaft due to magnetic flux fluctuations can be prevented to further reduce efficiency and temperature rise of the motor shaft. Thus, a motor with more excellent characteristics can be provided.

It is sectional drawing of the assembly | attachment state of the axial gap motor of one Embodiment of this invention. It is a perspective view of the motor shaft part of the axial gap motor of FIG. FIG. 3 is an enlarged perspective view of the low-loss electromagnetic member in FIG. 2. FIG. 3 is a perspective view of a state in which a binding band is wound around the configuration of FIG. 2. It is a perspective view of the motor shaft part of the radial gap motor of other embodiments of the present invention. The conductive part of the figure 8 coil structure of Drawing 5 is shown, (a) is a perspective view and (b) is a mimetic diagram showing a loop structure. The other example of the electroconductive part of FIG. 8 coil structure is shown, (a) is a perspective view, (b) is a schematic diagram which shows a loop structure. It is sectional drawing of a prior art example. It is a perspective view of the disassembled state of the axial gap motor of an existing application.

  Next, in order to describe the present invention in more detail, an embodiment will be described in detail with reference to FIGS. In these drawings, the motor shaft and the like are omitted as appropriate.

(One embodiment)
First, an embodiment applied to an axial gap motor having a three-dimensional magnetic path configuration will be described with reference to FIGS.

  FIG. 1 shows an axial gap motor 1 according to this embodiment. The axial gap motor 1 is roughly a stator having a double-sided pole structure between two disk-shaped rotors 3a and 3b that are supported by a motor shaft 2 and rotate. 4 is arranged.

  In each of the rotors 3a and 3b, for example, eight rotor magnetic poles (poles) 32 are arranged at equal intervals in the circumferential direction on the end surfaces of the disk-shaped yoke (core) 31 facing the stator 4.

  In the stator 4, the motor shaft 2 is loosely inserted in the center opening of a disk-shaped yoke (core) 41, and is excited to the N pole on one end face side (hereinafter referred to as the front side) of the yoke 41 facing the rotor 3 a, for example. The other end face of the yoke 41 facing the rotor 3b of the yoke 41 is provided with 12 stator poles (toothes) 42a (forming four magnetic poles at 90 degree intervals for each of the three phases) at equal intervals in the circumferential direction. Twelve stator magnetic poles (teeth) 42b excited on the S pole on the side (hereinafter referred to as the back side) are arranged at equal intervals while being shifted from the stator magnetic poles 42a in the circumferential direction. By disposing in this way, the number of magnetic poles of the stator 4 viewed from the motor shaft 2 is doubled to 24 poles.

  The yokes 31 and 41 are formed of laminated steel plates or dust cores, and the magnetic poles 32, 42a, and 42b are formed of dust cores.

  Each of the stator magnetic poles 42a and 42b is concentratedly wound with the exciting coils 5 of the phases A, B, and C in order. For example, when the A-phase exciting coil 5 is energized, All of the A-phase stator magnetic poles 42a are excited to N poles, and all four A-phase stator magnetic poles 42a spaced by 90 degrees on the back side of the stator 4 are excited to S poles. When the B-phase excitation coil 5 is energized, the four B-phase stator magnetic poles 42a spaced 90 degrees adjacent to the A-phase stator magnetic poles 42a on the front side of the stator 4 are all excited to the N-pole. The four B-phase stator magnetic poles 42a at intervals of 90 degrees adjacent to the respective A-phase stator magnetic poles 42b on the back side are excited to the S pole. Further, when the C-phase excitation coil 5 is energized, the four C-phase stator magnetic poles 42a at intervals of 90 degrees adjacent to the respective B-phase stator magnetic poles 42a on the front side of the stator 4 are all excited to the N-pole. All of the four C-phase stator magnetic poles 42a at intervals of 90 degrees adjacent to the respective B-phase stator magnetic poles 42b on the back side of the stator 4 are excited to the S pole. By this repetition, the four excited stator magnetic poles 42a and 42b on the front side and the back side of the stator 4 move so as to rotate, and the excited stator magnetic poles 42a and 42b and the rotor magnetic pole 32 in the vicinity thereof are magnetically coupled. The rotor 3a, 3b is rotated by a simple suction operation, and the axial gap motor 1 is driven.

  At this time, the magnetic flux of the N-pole stator magnetic pole 42a on the front side of the stator 4 is not provided with a conductor 7 and a low-loss electromagnetic member 8, which will be described later. The magnetic path passes through the magnetic pole 32, the motor shaft 2, the rotor magnetic pole 32 of the rotor 3b, and the S-pole stator magnetic pole 42b on the back side of the stator 4 to return to the N-pole stator magnetic pole 42a.

  In the present embodiment, a loop coil-shaped field coil 6 is provided outside the motor shaft 2 of the stator 4, and the magnetic flux is enhanced by the DC field of the field coil 6 to increase the torque.

  By the way, a magnetic flux passing through the motor shaft 2 formed of a solid magnetic material such as carbon steel (for example, S45C, S35C) due to a transient current change or a magnetoresistive change due to the rotation of the axial gap motor 1 or the like. When it fluctuates (pulsates), an eddy current is generated in the motor shaft 2 as shown by a solid arrow line in FIG.

  Therefore, in the case of the present embodiment, the following configuration is provided as a magnetic path forming member in the motor axial direction.

  FIG. 2 is a perspective view of a portion of the motor shaft 2. As the magnetic path forming member in the motor shaft direction, the motor shaft 2 is disposed on the innermost diameter side (center portion), and the motor shaft corresponding to the fluctuation of the magnetic flux is disposed outside the motor shaft 2. 2 is provided with a conductor portion 7a that shields the inflow to 2 and a high-permeability low-loss electromagnetic member 8a that forms a bypass magnetic path for the variation shielded by the conductor portion 7a on the outside thereof.

  In the case of this embodiment, the conductive portion 7a is an electrical conductor such as a sleeve-shaped metal that forms a short circuit coil. When the magnetic flux passing through the motor shaft 2 fluctuates (pulsates), the fluctuation causes a loop to the conductor portion 7a. A current is generated, and the fluctuation of the magnetic flux passing through the motor shaft 2 is canceled by the reverse magnetic flux based on the current, and the fluctuation is shielded. Therefore, the generation of the eddy current of the motor shaft due to the fluctuation can be prevented, and only the direct current component of the magnetic flux can pass through the motor shaft 2 to prevent the efficiency of the axial gap motor 1 from decreasing and the temperature of the motor shaft 2 from rising.

  In addition, since the conductive portion 7a is formed in a sleeve shape that is long in the motor shaft direction covering the entire portion between the rotors 3a and 3b of the motor shaft 2, a sufficient cross-sectional area of the current path for shielding the fluctuation of the magnetic flux The conductive portion 7a can be made thin, and the outer diameter of the entire magnetic path forming member in the motor axial direction can be reduced. The conductive portion 7a only needs to be provided in a ring shape at least on the input side of the magnetic path of the motor shaft 2. For example, the conductive portion 7a may be formed by providing ring coils near the rotors 3a and 3b.

  Next, by simply shielding the fluctuation (pulsation) component of the magnetic flux with the conductor portion 7a, the magnetic flux passing through the motor shaft 2 is only smoothed, so that it is possible to generate torque that should be originally generated when the magnetic flux increases. The torque of the axial gap motor 1 is reduced.

  Therefore, the low-loss electromagnetic member 8a described above is provided.

  FIG. 3 shows a low-loss electromagnetic member 8a, and the low-loss electromagnetic member 8a is, for example, a wound core of an electromagnetic steel strip. The winding core of this electromagnetic steel strip is electrically insulated at the beginning and end of winding, and does not constitute a short-circuiting coil, so that it can easily pass magnetic flux variation (pulsation component). The winding core of the electromagnetic steel strip has a high permeability, and the fluctuation of the magnetic flux is used for driving the axial gap motor 1 through the bypass magnetic path of the low-loss electromagnetic member 8a having a high permeability. The torque of the gap motor 1 does not decrease. Further, the low-loss electromagnetic member 8a having a high magnetic permeability does not increase in temperature due to the fluctuation of the magnetic flux.

  Therefore, in the case of the present embodiment, in the axial gap motor 1 in which the motor shaft 2 is formed of a magnetic material and used as a part of the magnetic path, generation of eddy currents in the motor shaft 2 due to fluctuations in magnetic flux is prevented and efficiency is lowered. In addition, the temperature increase of the motor shaft 2 can be prevented, and the axial gap motor 1 having excellent characteristics can be provided.

  Incidentally, the wound core of the electromagnetic steel strip forming the low-loss electromagnetic member 8a is preferably a directional electromagnetic steel strip whose axial permeability of the wound core is higher than that in the circumferential direction. An electromagnetic steel strip may be used. That is, in the case of the winding core of the directional electromagnetic steel strip, the steel strip is cut in the width direction rather than the rolling direction of the electromagnetic steel strip, and the winding thickness cannot be increased so much. Therefore, when a large winding thickness is required, the low-loss electromagnetic member 8a may be formed by a winding core obtained by cutting a non-directional electromagnetic steel strip in the rolling direction.

  In addition, the wound core of the electromagnetic steel strip forming the low-loss electromagnetic member 8a is bonded and wound by bonding or the like, and further, a binding band (stainless steel band) having a relatively high electrical resistivity for reinforcement on the outer periphery thereof. Etc.) is preferable.

  4 shows a state in which a binding band 9 such as a stainless steel band is wound around the outside of the low-loss electromagnetic member 8a. By winding the binding band 9, the low-loss electromagnetic member 8a or the like can be obtained even when the axial gap motor 1 rotates at high speed. The conductive portion 7 is not unwound. Further, since the binding band 9 also forms a loop in which magnetic fluxes are linked, the binding band 9 is made of the above-described stainless steel band or the like in order to increase the electrical resistance to reduce the current induced in the loop and prevent loss. Furthermore, it is more preferable that the binding band 9 is formed of a resin reinforcing material band such as a Kevlar cord.

(Other embodiments)
Next, instead of the conductive portion 7a of the above-described embodiment, an embodiment provided with a conductive portion 7b of a coil body having an 8-shaped coil structure will be described with reference to FIG. 1, FIG. 5, and FIG.

  This embodiment is also applied to the axial gap motor 1 having the three-dimensional magnetic path structure shown in FIG. 1, and substantially replaces the conductive portion 7a with the conductive portion 7b, and replaces the low-loss electromagnetic member 8a with the 8-shaped conductive portion 7b. It replaces with the sleeve-like low-loss electromagnetic member 8b which provided the cut | interruption in the cross location.

  FIG. 5 is a perspective view in which a part of the motor shaft 2 is cut away. In the case of this embodiment, the motor shaft 2 is arranged on the innermost diameter side (center portion) as a magnetic path forming member in the motor shaft direction. Further, a conductive portion 7b of a coil body having an 8-shaped coil structure is provided on the outside, the motor shaft 2 is surrounded by the inner diameter side loop portion 71 of the conductive portion 7b, and the low loss electromagnetic member 8b is surrounded by the outer diameter side loop 72. Further, the outer side of the outer diameter side loop 72 of the conductive portion 7b is covered with a sleeve-shaped reinforcing ring 10 made of a material having a large electrical resistance such as a Kevlar cord.

  6 (a) is a perspective view of the conductive portion 7b, and FIG. 6 (b) is a front view thereof. The conductive portion 7b is schematically shown in FIG. A deformed lower loop is arranged, and a portion surrounded by a broken line in both figures is an 8-shaped cross portion.

  The low-loss electromagnetic member 8b is formed of a dust core sleeve having a C-shaped cross section, for example, and has a high magnetic permeability like the low-loss electromagnetic member 8a.

  In order to give priority to reducing the fluctuation (pulsation) component of the magnetic flux flowing into the motor shaft 2, the conductive portion 7 b has a cross-sectional area in which the coil of the inner diameter side loop 71 surrounds the motor shaft 2 and the inner diameter side loop 71. The product of the number of turns of the coil is formed to be larger than the product of the cross-sectional area in which the coil of the outer diameter side loop 72 surrounds the low-loss electromagnetic member 8b and the number of turns of the coil of the outer diameter side loop 72. .

In this case, when the magnetic flux flowing into the motor shaft 2 fluctuates, the conductive portion 7b is linked to a clockwise (CW) loop and a counterclockwise (CCW) loop due to the well-known characteristic of the figure 8 coil structure. Since the induced current indicated by the broken arrow line in FIG. 6B flows so that the amount of magnetic flux change (for example, Δφ ₁ and Δφ ₂ in FIG. 6B) becomes the same magnitude, the magnetic flux flowing into the motor shaft 2 The magnetic flux density corresponding to the fluctuation (pulsation) is reduced and shielded, the generation of eddy current in the motor shaft 2 is suppressed, and eddy current loss is reduced.

  Further, in the short-circuit coil of the conductive portion 7a of the one embodiment, the loop current generated by the fluctuation (pulsation) component of the magnetic flux is consumed as Joule heat by the resistance of the short-circuit coil. In the conductive portion 7b having the structure, the magnetic flux generated in the outer diameter side loop 72 by the loop current induced by the pulsating component of the magnetic flux is utilized as a magnetomotive force for passing the magnetic flux through the bypass magnetic path of the low-loss electromagnetic member 8b.

  That is, in the case of the present embodiment, when the magnetic flux passing through the motor shaft 2 fluctuates (pulsates), the conductor portion 7b has an inner diameter side loop 71 and an outer diameter side loop 72 as in the case of the coil body having the known 8-shaped coil structure. Inducted current of the interlinkage magnetic flux based on the fluctuation of the magnetic flux flows, and the magnetic flux fluctuation flowing into the motor shaft 2 is shielded by the magnetic flux of the inner diameter side loop 71 generated by the induced current, and the outer diameter side loop 72 The magnetic flux is used without waste as a magnetomotive force for passing through the bypass magnetic path of the low-loss electromagnetic member 8b.

  Therefore, in the case of this embodiment, when the motor shaft 2 is formed of a magnetic material and used as a part of a magnetic path, generation of eddy currents in the motor shaft 2 due to fluctuations in magnetic flux is prevented, and the efficiency is further improved. The axial gap motor 1 can be prevented from being lowered and the temperature of the motor shaft 2 being raised, and further excellent in characteristics.

  The present invention is not limited to the above-described embodiments, and various modifications other than those described above can be made without departing from the spirit thereof. For example, in the other embodiments, Instead of the conductor portion 7b, a conductor having an 8-shaped coil structure formed by double 8-shaped coils, in which the inner diameter side loops 71, the outer diameter side loops 72, and the inner diameter side of both coils are connected to each other. You may make it provide a part.

  FIG. 7A is a perspective view of the conductive portion 7c formed by the above-described double 8-shaped coils 73 and 74, and FIG. 7B is a schematic diagram showing the coil structure. In this case, the inner diameter side loop portion 71 and the outer diameter side loop portion 72 of the 8-shaped coils 73 and 74 are connected to each other on the inner diameter side and the outer diameter side. In addition, the part enclosed with the broken line of FIG.7 (b) is a cross part of figure 8.

  Next, the conductive portions 7a to 7c may be formed of various conductive material rings and sleeves, and the low-loss electromagnetic members 8a and 8b may be various high-permeability electromagnetic members.

  Next, the present invention can be applied to an axial gap motor having various configurations in which a motor shaft is formed of a magnetic material and used as a part of a magnetic path. The present invention can be similarly applied to a radial gap motor used as a part.

  The motor to which the present invention is applied may be an axial gap motor or a radial gap motor for various uses such as a drive motor for an electric vehicle.

DESCRIPTION OF SYMBOLS 1 Axial gap motor 2 Motor shaft 3a, 3b Rotor 7a-7c Conductor part 8a, 8b Low loss electromagnetic member

Claims (2)

In a motor having a magnetic path configuration in which the magnetic flux between the stator and the rotor passes through the magnetic motor shaft in the axial direction.
Outside the motor shaft,
A conductor portion that shields the flow of the magnetic flux from flowing into the motor shaft;
A motor comprising: a high-permeability low-loss electromagnetic member that forms a bypass magnetic path that is shielded by the conductor portion. The motor according to claim 1, wherein
The conductor portion is formed by a coil body having an 8-shaped coil structure having an inner diameter side loop and an outer diameter side loop outside the inner loop,
The motor, wherein the inner diameter side loop surrounds a motor shaft, and the outer diameter side loop surrounds the conductor portion.