JP2012010446A - Axial gap type motor for electric car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an axial gap type motor for an electric car capable of increasing rotation torque by reducing magnetic flux leakage from an excitation coil.SOLUTION: A motor MTa for an electric car comprises: a wheel WHa equipped with a wheel base WB functioning as a rotor and having a plurality of permanent magnets 12 provided at predetermined intervals in a circumferential direction spacing a prescribed distance from a center; a first excitation coil 20 and a second excitation coil 30 facing both end faces of the wheel base WB in an axial direction with a space; a first stator core 40 and a second stator core 50 respectively facing the end faces, the opposite faces from the ones facing the wheel base WB, of the first excitation coil 20 and second excitation coil 30; and a connection core 60 connecting the first stator core 40 with the second stator core 50 through outside of the wheel WHa.

Description

  The present invention relates to an axial gap type electric vehicle motor that is provided directly on a drive wheel of a vehicle and drives the drive wheel.

  In recent years, so-called hybrid vehicles and electric vehicles using motors (motors) have become popular because they can improve overall fuel efficiency and reduce total carbon dioxide emissions in order to reduce the burden on the global environment. Has been researched and developed. In addition to such hybrid vehicles and electric vehicles, electric motorcycles such as electric motorcycles, electric scooters, and assist bicycles, and electric wheelchairs are known as vehicles using motors.

  Vehicles equipped with such a motor have common problems, for example, the problem of cogging torque that makes riding comfort worse and the problem of increased torque per volume. In order to solve such a problem, for example, Patent Document 1 proposes an electric motorcycle motor.

  The motor for an electric motorcycle disclosed in Patent Document 1 includes an electric motor that drives a driving wheel of the electric motorcycle via a speed reducer, and the electric motor includes a rotor that surrounds a stator. It is an outer rotor type brushless motor, the outer shape of the stator is 150 to 200 mm, a coil is concentratedly wound around the stator, the number of poles of the rotor is 24, and the number of slots of the stator is A plurality of arc-shaped magnets arranged in the circumferential direction on the rotor as a main magnetic circuit is a neodymium magnet, and an air gap between the stator and the rotor is a thickness of the neodymium magnet. The circumferential width of the winding portion of the teeth provided on the stator is 0.4 to 0.6 times the circumferential width of the tip portion of the teeth. It is. According to Patent Document 1, the motor for an electric motorcycle having such a configuration can reduce the influence of cogging torque, can generate a large torque, and can be made compact.

JP 2009-284726 A

  By the way, since the motor for electric motorcycles disclosed in Patent Document 1 drives the drive wheels via the speed reducer, mechanical loss occurs, and it is difficult to efficiently drive the drive wheels. For this reason, it is conceivable to adopt an in-wheel system in which a motor is incorporated in a drive wheel. However, since it is a radial gap type and an outer roller type, the radial gap position is determined by the constraints caused by the size of the stator, etc. Since a rotational torque is generated at a relatively large radial position, for example, at the center of the radius, a relatively large current is required to obtain a large rotational torque.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide an axial gap type electric vehicle motor that can increase rotational torque by reducing leakage of magnetic flux generated by an exciting coil. Is to provide.

  As a result of various studies, the present inventor has found that the above object is achieved by the present invention described below. That is, an axial gap type electric vehicle motor according to an aspect of the present invention includes a wheel including a wheel base, a rotor including a plurality of permanent magnet pieces, and an excitation facing the end surface in the axial direction of the rotor with a space therebetween. A stator having a coil and a core through which the magnetic flux generated by the exciting coil is passed, and the plurality of permanent magnet pieces in the rotor are located at a predetermined distance from the center of the wheel base of the wheel. The stator excitation coil is disposed at a predetermined interval in the circumferential direction, and the stator excitation coil is opposed to the first excitation coil facing the one end surface in the axial direction of the rotor with the interval, and the other end surface in the axial direction of the rotor And a second exciting coil opposed to each other with a space therebetween, and the core of the stator faces the rotor in the first exciting coil A first stator core facing the other end face of the first exciting coil facing one end face of the first exciting coil, and a second exciting coil facing the other end face of the second exciting coil facing the rotor in the second exciting coil. And a connecting core that connects the first stator core and the second stator core through the outside of the wheel.

  In the axial gap type electric vehicle motor having such a configuration, the first and second excitation coil other end faces of the first and second excitation coils serve as open ends of the magnetic flux lines. Magnetic flux is collected by the first and second stator cores facing the other end surfaces of the first and second exciting coils of the first and second stator coils, respectively, and the magnetic flux lines collected by the first and second stator cores are passed through the connecting core, thereby closing the magnetic flux lines. It can be. As a result, the axial gap type electric vehicle motor having such a configuration can reduce the leakage magnetic flux and increase the rotational torque.

  In another aspect, in the above-mentioned axial gap type electric vehicle motor, each of the first and second exciting coils is a strip-shaped conductor member, and the width direction of the strip-shaped conductor member is the rotor. It is characterized by being spirally wound so as to substantially coincide with the direction of the magnetic flux formed by the permanent magnet.

  In the axial gap type electric vehicle motor having such a configuration, each of the first and second exciting coils is a strip-shaped (tape-shaped, ribbon-shaped) conductor member, and the width direction of the strip-shaped conductor member is the above-described width direction. Since it is wound in a spiral shape so as to substantially coincide with the direction of the magnetic flux formed by the permanent magnet of the rotor, the cross-sectional area of the conductor member on the surface orthogonal to the magnetic flux is reduced. For this reason, the axial gap type electric vehicle motor having such a configuration can reduce the eddy current loss and improve the efficiency thereof.

  According to another aspect, in the above-mentioned axial gap type electric vehicle motor, the rotor includes a magnetic piece having a magnetic property different from that of the wheel base instead of the permanent magnet piece, There are a plurality of second exciting coils, respectively, and the plurality of first and second exciting coils are supplied with electric power so that the rotor rotates with respect to the stator by a switched reactance action.

  Since the axial gap type electric vehicle motor having such a configuration includes a magnetic piece instead of the permanent magnet, it is not necessary to use a permanent magnet containing a relatively expensive rare metal, and the cost can be reduced. In addition, since the axial gap type electric vehicle motor having such a configuration does not use permanent magnets for wheels, for example, iron powder or the like is not adsorbed from the road surface, so that removal thereof is unnecessary.

  According to another aspect, in the above-mentioned axial gap type electric vehicle motor, the stator core is magnetically isotropic and is formed by molding soft magnetic powder. .

  The axial gap type electric vehicle motor having such a configuration can obtain desired magnetic characteristics relatively easily and can be formed into a desired shape relatively easily.

  The axial gap type electric vehicle motor according to the present invention can increase the rotational torque by reducing leakage of magnetic flux generated by the exciting coil.

It is a perspective view which shows the external appearance structure of the wheel carrying the motor for electric vehicles in 1st Embodiment. It is a figure which shows the structure of the motor for electric vehicles shown in FIG. It is a figure which shows the external appearance structure of the wheel carrying the motor for electric vehicles in 2nd Embodiment.

  Hereinafter, an embodiment according to the present invention will be described with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted suitably. Further, in this specification, when referring generically, it is indicated by a reference symbol without a suffix, and when referring to an individual configuration, it is indicated by a reference symbol with a suffix.

(First embodiment)
A case of an electric scooter will be described as an example of an electric vehicle using the axial gap type electric vehicle motor in the present embodiment.

  FIG. 1 is a perspective view showing an external configuration of a wheel on which the electric vehicle motor according to the first embodiment is mounted. In FIG. 1, the first excitation stator core is shown in phantom so that the inside can be seen through. In FIG. 1, only one side of the wheel is shown. FIG. 2 is a diagram showing a configuration of the electric vehicle motor shown in FIG. 1. 2A is a perspective view, and FIG. 2B is a front view in a state where the first stator core 40 and the first exciting coil 30 are removed.

  The electric scooter generally includes a vehicle body frame, a front wheel (steering wheel) rotatably supported by a front fork (front arm) that is steerable forward of the vehicle body frame, and a travel direction of the vehicle body frame. A rear wheel rotatably supported by a rear fork (rear arm) provided at the rear; a handle provided at an upper end of the front fork for steering the front wheel; a seat provided on the body frame and seated by a driver; And an electric vehicle motor MTa. The electric vehicle motor MTa is provided directly on at least one of the front wheels and the rear wheels (in-wheel system). That is, the electric vehicle motor MTa is applied to the wheels so that the rotational torque generated by the electric vehicle motor MTa can be directly transmitted to the wheels without using a reduction gear such as a gear. These wheels and the electric vehicle motor MTa are configured.

  For example, as shown in FIG. 1, such a wheel (wheel) WHa includes a wheel base WB, a tire TY disposed on the outer periphery of the wheel base WB, and the wheel base WB functioning as a rotor. And an electric vehicle motor MTa provided integrally therewith.

  The wheel base WB includes a disc-shaped wheel disc WD and a substantially cylindrical wheel rim WR provided integrally with the outer periphery of the wheel disc WD. The wheel base WB includes a tire TY on the outer periphery of the wheel rim WR. Is assembled.

  An electric vehicle motor MTa is integrally provided on the wheel base WB of the wheel WHa. More specifically, in the present embodiment, the wheel disk WD in the wheel base WB is provided with a plurality of permanent magnet pieces 12 in the peripheral portion thereof. That is, as shown in FIGS. 1 and 2, the wheel disk WD has a circular shape that is substantially the same shape as the outer shape of the permanent magnet piece 12 at a predetermined distance from the center of the wheel disk WD at equal intervals in the circumferential direction. The same number of openings WDA as the plurality of permanent magnet pieces 12 are formed, and a plurality of permanent magnet pieces 12 are fitted into each of the openings WDA and bonded and fixed by, for example, an epoxy-based adhesive or the like. Thereby, the wheel disc WD is configured to function as a rotor. In the example shown in FIGS. 1 and 2, the permanent magnet piece 12 has a substantially disk shape (substantially cylindrical shape), but the shape is not particularly limited. The plurality of permanent magnet pieces 12 have their magnetic poles oriented in the axial direction (there are magnetic poles S and N on each surface of the wheel disk WD), and the magnetic poles of the permanent magnet pieces 12 adjacent to each other in the circumferential direction are , Facing opposite directions.

  An electric vehicle motor MTa that functions such a wheel disk WD of the wheel base WB as a rotor is an electric motor having an axial gap structure (axial gap type electric motor), the rotor including the plurality of permanent magnet pieces 12, and the rotor The stator includes an exciting coil facing the end face in the axial direction with a gap and a core through which the magnetic flux generated by the exciting coil passes. More specifically, as shown in FIGS. 1 and 2, the electric vehicle motor MTa includes the wheel disk WD of the wheel base WB including the plurality of permanent magnet pieces 12 that function as a rotor (rotor) as described above. And first and second exciting coils 20, 30; first and second stator cores (yokes) 40, 50; and a connecting core (connecting yoke) 60, and a wheel disc WD (of the wheel disc WD). The plane is perpendicular to the axis. The first and second stator cores 40 and 50 and the connecting core 60 constitute the core. The first and second exciting coils 20 and 30, the first and second stator cores 40 and 50 and the connecting core 60 constitute the stator. (Stator) is configured.

  Each of the first and second exciting coils 20 and 30 is obtained by winding a long conductor member covered with insulation for a predetermined number of times, and generates a magnetic field when energized.

  In the electric vehicle motor MTa of the present embodiment, since it is driven by three-phase AC power, the number of exciting coils (the number of slots) is 3 × n (n is a positive integer), and the permanent magnet piece 12 The number (number of poles) is set to 4 × n so that the ratio of the number of slots: number of poles = 3: 4 is obtained in order to reduce the cogging torque. In the example shown in FIGS. 1 to 3, the number of slots is 3 and the number of poles is set to 24. The first excitation coil 20 includes a U-phase first excitation coil 20u and a V-phase first excitation coil 20v. And a W-phase first excitation coil 20w, the second excitation coil 30 includes a U-phase second excitation coil 30u, a V-phase second excitation coil 30v, and a W-phase second excitation coil 30w, and The permanent magnet piece 12 includes 24 permanent magnet pieces 12-1 to 12-24.

  These U-phase, V-phase, and W-phase first excitation coils 20u, 20v, and 20w are composed of coils 21u, 21v, and 21w and coils 21u, 21v, and 21w, respectively, three phases of U-phase, V-phase, and W-phase. In order to supply phase alternating current, it is provided with a pair of connection terminals 22u-1, 22u-2; 22v-1, 22v-2; 22w-1, 22w-2, and U phase, V phase and W phase The two excitation coils 30u, 30v, 30w are provided with a pair of coils 31u, 31v, 31w and a pair of coils 31u, 31v, 31w, respectively, for supplying a three-phase alternating current of U phase, V phase, and W phase. Connection terminals 32u-1, 32u-2; 32v-1, 32v-2; 32w-1, 32w-2 are provided.

  These coils 21u, 21v, 21w; 31u, 31v, 31w are each configured by winding a long conductor member having an insulating coating such as a round cross section (◯ shape) or a cross section rectangle (□ shape). However, in the present embodiment, these coils 21u, 21v, 21w; 31u, 31v, 31w are respectively strip-shaped conductor members (band-shaped wires) that are covered with insulation, and the width direction of the conductor members is the coil 21u. , 21v, 21w; 31u, 31v, 31w. The band shape refers to a case where the width (axial length) W is larger than the thickness (diameter length) t of the conductor member, that is, between the width W and the thickness t, W > T (W / t> 1) is established. As described above, the first and second exciting coils 20 (20u, 20v, 20w) and 30 (30u, 30v, 30w) of the present embodiment have a so-called flat-wise winding structure and reduce so-called eddy current loss. Is advantageous.

  Preferably, the coils 21u, 21v, 21w; 31u, 31v, 31w are respectively strip-shaped conductor members coated with insulation, and the width direction of the strip-shaped conductor members functions as a rotor as a wheel base WB. The wheel disk WD is wound in a spiral shape so as to substantially coincide with the direction of the magnetic flux formed by the permanent magnet piece 12 of the wheel disk WD. By comprising in this way, since the cross-sectional area of the said conductor member in the surface orthogonal to magnetic flux becomes small, the eddy current loss can be made small and the efficiency can be improved.

  When such a strip-shaped conductor member is used, the conductor layer and the insulating layer are laminated in the thickness direction to form the coils 21u, 21v, 21w; 31u, 31v, 31w. The strip-shaped conductor member (conductor layer member) is made of, for example, copper, aluminum, or an alloy thereof. The strip-shaped conductor member is covered with an insulating resin or the like, and insulation is ensured so that the tape surfaces do not come into electrical contact with each other. Insulating properties may be secured by sandwiching an insulating sheet.

Generally, the alternating current flowing through the coil flows only in the range up to the skin thickness δ of the conductor member, and the current does not flow uniformly over the entire cross section of the conductor member. This skin thickness δ is generally defined as δ = (2 // when the frequency (angular frequency) of the alternating current flowing in the coil is ω, the magnetic permeability of the conductor member of the coil is μ, and the electric conductivity is σ. ωμσ) ^1/2 . Here, if the thickness of the strip-shaped conductor member is larger than the skin thickness δ, there is an invalid portion where current does not flow in the conductor member, and the volume of the conductor member increases unnecessarily, and the coil Winding efficiency is reduced. Furthermore, even when the magnetic field is applied parallel to the tape-like conductor plane, the loss of eddy current flowing through the conductor member increases. On the other hand, if the thickness of the conductor member is less than or equal to the skin thickness δ, there is no useless portion of the conductor member through which no current flows, the current flows through the entire conductor member, and the efficiency of the coil winding is improved. It becomes possible to constitute a coil. Furthermore, if the magnetic field is applied parallel to the tape-like conductor plane, the loss of eddy current flowing through the conductor member can be greatly reduced. Therefore, a conductor member having a thickness equal to or less than the skin thickness δ is preferably used as the wire for the coils 21u, 21v, 21w; 31u, 31v, 31w.

  Further, when the thickness of the strip-shaped conductor member is t and the width of the strip-shaped conductor member is W, the width W is determined by the magnitude of the current flowing through the strip-shaped conductor member, but t / W ≦ 1 is preferably satisfied, and more preferably, the condition of t / W ≦ 1/10 is satisfied. In the above example, the limit t / W = 1/30. When t / W ≦ 1/10, the effective space factor of the conductor member can be improved, and eddy current loss can be significantly reduced.

  The first and second exciting coils 20 and 30 are air-core coils and are coreless in order to reduce cogging torque.

  The U-phase, V-phase, and W-phase first excitation coils 20u, 20v, and 20w in the first excitation coil 20 are equidistant in the circumferential direction in this order so as to face one magnetic pole surface of the permanent magnet piece 12. The U-phase, V-phase, and W-phase first excitation coils 30u, 30v, 30w in the second excitation coil 30 are arranged in the circumferential direction in this order so as to face the other magnetic pole surface of the permanent magnet piece 12. Arranged at equal intervals. Therefore, the U-phase, V-phase, and W-phase first excitation coils 20u, 20v, 20w in the first excitation coil 20 and the U-phase, V-phase, and W-phase first excitation coils 30u, 30v, 30w in the second excitation coil 30 Are opposed to each other in phase with each other via a wheel disc WD of the wheel base WB that functions as a rotor.

  Each of the first and second stator cores 40 and 50 is, for example, an arc-shaped plate having a predetermined width and a predetermined length, and an inner surface in the axial direction (a surface facing the wheel disk WD of the wheel base WB). On the side), a recess is formed. The recesses of the first stator core 40 are three such that the coils 21u, 21v, 21w of the U-phase, V-phase, and W-phase first excitation coils 20u, 20v, 20w can be fitted side by side in the circumferential direction. It is the shape which connected the cylindrical shape of. The diameter of the columnar shape is a diameter corresponding to the outer diameter of each coil 21u, 21v, 21w. The first stator core 40 includes a pair of connection terminals 22u-1, 22u-2; 22v-1, 22v-2; 22w- in the U-phase, V-phase, and W-phase first excitation coils 20u, 20v, 20w. A plurality of through holes are formed at appropriate positions in order to pass through 1, 2 and 2-2. Similarly, the recesses of the second stator core 50 can fit the coils 31u, 31v, 31w of the U-phase, V-phase, and W-phase second excitation coils 30u, 30v, 30w side by side in the circumferential direction. It is the shape which connected three cylindrical shapes. The diameter of the columnar shape is a diameter corresponding to the outer diameter of each coil 31u, 31v, 31w. The second stator core 50 includes a pair of connection terminals 32u-1, 32u-2; 32v-1, 32v-2; 32w- in the U-phase, V-phase, and W-phase second excitation coils 30u, 30v, 30w. In order to insert 1, 32w-2, a plurality of through holes are formed at appropriate positions.

  The first and second stator cores 40 and 50 are each made of a material having predetermined magnetic characteristics. It is preferable that the first and second stator cores 40 and 50 have a relatively high magnetic permeability in order to better collect magnetic flux lines. Each of the first and second stator cores 40 and 50 may be formed of, for example, a silicon steel plate or an electromagnetic steel plate, but in this embodiment, it is easy to realize a desired magnetic property and easy to form a desired shape. From the viewpoint, it is preferable that, for example, it is magnetically isotropic and is formed by molding a mixture of soft magnetic powder and nonmagnetic powder. The mixing ratio ratio between the soft magnetic powder and the non-magnetic powder can be adjusted relatively easily, and the magnetic characteristics of the first and second stator cores 40 and 50 can be adjusted by appropriately adjusting the mixing ratio. It is possible to easily realize the magnetic characteristics. Further, since it is a mixture of soft magnetic powder and non-magnetic powder, it can be formed into various shapes, and the shapes of the first and second stator cores 40 and 50 can be easily formed into desired shapes. It becomes possible.

  This soft magnetic powder is a ferromagnetic metal powder. More specifically, for example, pure iron powder, iron-based alloy powder (Fe-Al alloy, Fe-Si alloy, Sendust, Permalloy, etc.) and amorphous powder, Furthermore, the iron powder etc. with which electric insulation films, such as a phosphoric acid system chemical film, were formed on the surface are mentioned. These soft magnetic powders can be produced, for example, by a method of making fine particles by an atomizing method or the like, or a method of finely pulverizing iron oxide or the like and then reducing it. In general, since the saturation magnetic flux density is large when the magnetic permeability is the same, the soft magnetic powder is particularly preferably a metal-based material such as the above pure iron powder, iron-based alloy powder, and amorphous powder.

  Such first and second stator cores 40 and 50 are each formed by mixing iron powder as a soft magnetic powder and resin as a nonmagnetic powder by using, for example, known conventional means. For example, it is compacted.

  The connecting core 60 has a substantially ring shape with a notch (a substantially ring shape with a notch, a donut shape with a notch, a U shape), and is made of a material having a predetermined magnetic property. Two stator cores 40 and 50 are formed in the same manner. In the example shown in FIG. 1, the number of the connecting cores 60 is one, but it corresponds to each of the U-phase, V-phase and W-phase first and second exciting coils 20u; 30u, 20v; 30v, 20w; In addition, three first to third connection cores arranged in parallel to each other may be provided.

  In the first stator core 40, the pair of connection terminals 22u-1, 22u-2; 22v-1, 22v-2; 22w-1, 22w-2 are provided in the recesses. The U-phase, V-phase, and W-phase first exciting coils 20u, 20v, 20w are fitted and fixed by, for example, an adhesive so that the second stator core 50 has the aforementioned In the recess, the U phase, V so that each of the pair of connection terminals 32u-1, 32u-2; 32v-1, 32v-2; 32w-1, 32w-2 faces the outside from each through hole. Each of the phase and W phase second exciting coils 30u, 30v, 30w is fitted and fixed by, for example, an adhesive. The first excitation coil 20 of the first stator core 40 is disposed at a predetermined interval on one end surface in the axial direction of the wheel disk WD of the wheel base WB at one end surface of the first excitation coil, and 2 One end of the connecting core 60 so that the second excitation coil 30 of the stator core 50 is disposed at a predetermined interval on the other end surface in the axial direction of the wheel disk WD of the wheel base WB at one end surface of the second excitation coil. Are connected to the first stator core 40 by, for example, an adhesive, and the other end of the connection core 60 is connected to the second stator core 50 by, for example, an adhesive.

  Thus, the first excitation coil 20 (20u, 20v, 20w) is opposed to the one end face in the axial direction of the wheel disk WD (rotor) of the wheel base WB with the space therebetween, and the second excitation coil 30 (30u, 30v). , 30w) is configured to face the other end surface in the axial direction of the wheel disk WD (rotor) of the wheel base WB with the gap therebetween. Further, the first stator core 40 is formed on the other end surface of the first exciting coil 20 facing the wheel disk WD (rotor) of the wheel base WB in the first exciting coil 20 (20u, 20v, 20w). The second excitation core is opposed so as to be covered, and the second stator core 50 is opposed to one end face of the second excitation coil facing the wheel disk WD (rotor) of the wheel base WB in the second excitation coil 30 (30u, 30v, 30w). The electric vehicle motor MTa is configured so as to face the other end face of the coil so that the connecting core 60 connects the first stator core 40 and the second stator core 50 through the outside of the wheel WHa.

  That is, one end surface of the first excitation coil of the first excitation coil 20 (20u, 20v, 20w) is opposed to the one end surface in the axial direction of the wheel disk WD (rotor) of the wheel base WB with the space therebetween. The other end surface of the first excitation coil of one excitation coil 20 (20u, 20v, 20w) faces the first stator core 40 so as to be covered by the first stator core 40. Similarly, one end surface of the second excitation coil of the second excitation coil 30 (30u, 30v, 30w) is opposed to the other end surface in the axial direction of the wheel disk WD (rotor) of the wheel base WB with the space therebetween, The other end surface of the second exciting coil of the second exciting coil 30 (30u, 30v, 30w) faces the second stator core 50 so as to be covered by the second stator core 50.

  Further, a lot-shaped shaft (not shown) is inserted and fixed to the wheel disk WD of the wheel base WB. For example, when the rear wheel is a drive wheel, both end portions of the shaft (not shown) are rotatably supported by the rear fork.

  In the electric vehicle motor MTa having such a configuration, for example, the DC power of the storage battery is converted into three-phase AC power by an inverter, and the converted U-phase, V-phase, and W-phase AC power is converted into the first excitation coil. Power is supplied to each of 20u, 20v, and 20w, and power is supplied to each of the second excitation coils 30u, 30v, and 30w. Due to the feeding of the three-phase AC power, an electromagnetic force is generated in each of the first and second exciting coils 20u, 20v, 20w; 30u, 30v, 30w with a predetermined phase difference, and the wheel of the wheel base WB is generated by this electromagnetic force. The wheel disk WD of the wheel base WB rotates by being attracted and repelled like a so-called linear motor between the permanent magnet pieces 12 (12-1 to 12-24) of the disk WD (rotor).

  Here, the magnetic flux lines coming out from the other end face of the first exciting coil 20 (20u, 20v, 20w) are collected by the first stator core 40, and the collected magnetic flux lines are connected from the first stator core 40. It passes through the core 60, exits from the second stator core 50, enters the other end face of the second excitation coil 30 (30u, 30v, 30w), and enters the second end of the second excitation coil 30 (30u, 30v, 30w). The excitation coil circulates from one end face of the first excitation coil 20 (20u, 20v, 20w) to one end face of the first excitation coil 20 via the wheel disk WD (rotor) of the wheel base WB. Alternatively, the magnetic flux lines coming out from the other end face of the second exciting coil of the second exciting coil 30 (30u, 30v, 30w) are collected by the second stator core 50, and the collected magnetic flux lines are collected from the second stator core 50 to the connecting core. 60, exits the first stator core 40, enters the other end face of the first excitation coil 20 (20u, 20v, 20w), and enters the first excitation coil 20 (20u, 20v, 20w). The coil flows from one end face of the coil to the one end face of the second excitation coil 30 (30u, 30v, 30w) via the wheel disk WD (rotor) of the wheel base WB.

  As described above, in the electric vehicle motor MTa of the present embodiment, the other end surfaces of the first and second excitation coils 20 and 30 of the first and second excitation coils 20 and 30 become the open ends of the magnetic flux lines. Collected by the first and second stator cores 40 and 50 facing the other end surfaces of the first and second excitation coils of the first and second excitation coils 20 and 30, respectively, and collected by the first and second stator cores 40 and 50, respectively. The magnetic flux lines thus made are circulated by passing through the connecting core 60, and the magnetic flux lines become a closed loop. As a result, the electric vehicle motor MTa of the first embodiment can reduce the leakage magnetic flux and increase the rotational torque.

  In the electric vehicle motor MTa of the present embodiment configured as described above, if the conductor members of the coils 21u, 21v, 21w; 31u, 31v, 31w are cylindrical wires, the flow of current is reduced due to the skin effect. On the other hand, as described above, by using a strip-shaped wire, the current density is improved by reducing the area on the inner side in the cross section of the wire (current channel cross section), and further, the eddy current Can be reduced, a larger torque can be obtained, AT (ampere turn) is small, assembly (and disassembly at the time of recycling) is easy, and the structure of the winding itself is strengthened. And fatigue due to magnetostriction.

  In the electric vehicle motor MTa described above, the thermal conductivity filled in the gaps between the coils 21u, 21v, 21w; 31u, 31v, 31w and the first and second stator cores 40, 50 on the stator side where the coils 21u, 31v, 31w are mounted. It is preferable to further include these members. Even if it is wound to the same thickness, in the case of a cylindrical wire rod, air enters between the wires, resulting in poor heat conduction. In such a configuration, a strip-shaped wire rod is used, and a so-called single pancake winding structure is used. By adopting, the heat generated in the coils 21u, 21v, 21w; 31u, 31v, 31w is converted into the coils 21u, 21v, 21w; 31u, 31v, 31w by the good thermal conductivity of the wire such as copper. Can be conducted to the first and second stator cores 40, 50 through the heat conductive member with good thermal conductivity, and the coils 21u, 21v, 21w; 31u, 31v , 31w can be improved. Thus, the field current can be increased to obtain a large torque, or the same torque can be reduced in size. The same applies to the second embodiment. In general, the thermal insulator has a conductivity of about 1 W / mK or less, and the thermal conductive member may have a high thermal conductivity of 100 W / mK or more.

  Next, another embodiment will be described.

(Second Embodiment)
FIG. 3 is a diagram illustrating an external configuration of a wheel on which the motor for an electric vehicle according to the second embodiment is mounted. In FIG. 3, the first excitation stator core is indicated by a virtual line so that the inside can be seen through. FIG. 3 shows only one side of the wheel.

  The electric vehicle motor MTa in the first embodiment rotates the wheel base WB functioning as a rotor by the magnetic force acting between the first and second exciting coils and the permanent magnet piece 12, but the second embodiment. As shown in FIG. 3, the electric vehicle motor MTb in the embodiment is a magnetic piece having a magnetic property different from that of the wheel disk WD of the wheel base WB, instead of the permanent magnet pieces 12 (12-1 to 12-24). 70 (70-1 to 70-24), and constitutes a switched reactance motor. For this reason, since the remaining structure in 2nd Embodiment is the same as that of the motor MTa for electric vehicles in 1st Embodiment, the description is abbreviate | omitted. A switched reactance motor is an electric motor that generates torque by switching the timing of energizing an exciting coil in accordance with the rotation of the rotor and using a magnetic attractive force acting between the magnetic poles of the rotor and the stator.

  An electric vehicle motor MTb is integrally provided on the wheel base WB of the wheel WHb of the second embodiment. More specifically, in the present embodiment, the wheel disk WD in the wheel base WB is provided with a plurality of magnetic pieces 70 at the peripheral portion thereof. That is, as shown in FIG. 3, the wheel disk WD has a circular opening WDB that is located at a predetermined distance from the center of the wheel disk WD and is approximately the same as the outer shape of the magnetic piece 70 at equal intervals in the circumferential direction. However, the same number as the plurality of magnetic body pieces 70 is formed, and the plurality of magnetic body pieces 70 are fitted and fixed to each opening WDB by, for example, an epoxy adhesive or the like. Thereby, the wheel disc WD is configured to function as a rotor. In the example shown in FIG. 3, the magnetic piece 70 has a substantially disc shape (substantially cylindrical shape), but the shape is not particularly limited.

  The magnetic piece 70 is made of a material having magnetism different from that of the wheel disc WD in the wheel base WB. For example, the magnetic piece 70 is made of a material having magnetism stronger than that of the wheel disc WD in the wheel base WB. In order to generate a larger torque, the magnetic piece 70 is preferably made of a ferromagnetic material that can have spontaneous magnetization even without an external magnetic field. More preferably, it is made of a material such as iron, cobalt, nickel and gadolinium (18 ° C.) exhibiting ferromagnetism at about 25 ° C.

  The electric vehicle motor MTb in the present embodiment includes a power supply control unit (not shown), and the power supply control unit allows the plurality of first and second excitation coils 20u, 20v, 20w; 30u, 30v, 30w to be switches. Power is supplied so that the rotor rotates with respect to the stator by dereactance action.

  More specifically, first, in the first and second exciting coils 20, 30, the first exciting coil 20u and the second exciting coil 30u are electrically connected in series, and the first exciting coil 20v and the second exciting coil 20u are electrically connected in series. The coil 30v is electrically connected in series, and the first excitation coil 20w and the second excitation coil 30w are electrically connected in series. Among the three sets electrically connected in series with each other, power is supplied to the magnetic piece 70 and the set of coils having the strongest attractive force to generate torque in the rotational direction. As the wheel base WB rotates, the attractive magnetic field can be rotated by batting the power supply to the adjacent coil in the rotation direction. Thus, by determining the excitation timing (power supply timing) according to the relative position between the wheel base WB and the first and second excitation coils 20, 30, the wheel base WB (wheel WHb) can be moved in any direction (clockwise). (Alternatively, the rotational torque can be continuously applied counterclockwise).

  As with the electric vehicle motor MTa in the first embodiment, the electric vehicle motor MTb in the second embodiment can reduce the leakage magnetic flux and increase the rotational torque. And since the motor MTb for electric vehicles in 2nd Embodiment is provided with the magnetic body piece 70 instead of the permanent magnet piece 12, it uses the permanent magnet containing a comparatively expensive rare metal like a neodymium system permanent magnet etc., for example. The cost can be reduced. Moreover, since the motor MTb for electric vehicles in 2nd Embodiment does not use the permanent magnet piece 12 for the wheel WHb, for example, it does not adsorb | suck iron powder etc. from a road surface, Therefore The removal is also unnecessary.

  In order to express the present invention, the present invention has been properly and fully described through the embodiments with reference to the drawings. However, those skilled in the art can easily change and / or improve the above-described embodiments. It should be recognized that this is possible. Therefore, unless the modifications or improvements implemented by those skilled in the art are at a level that departs from the scope of the claims recited in the claims, the modifications or improvements are not covered by the claims. To be construed as inclusive.

MTa, MTb Axial gap type electric vehicle motor 12 Permanent magnet pieces 20, 20u, 20v, 20w First excitation coils 30, 30u, 30v, 30w Second excitation coil 40 First stator core 50 Second stator core 60 Connection core 70 Magnetic body Fragment

Claims (4)

A wheel with a wheelbase;
A rotor comprising a plurality of permanent magnet pieces;
A stator comprising an exciting coil opposed to the axial end face of the rotor with a gap and a core through which a magnetic flux generated by the exciting coil passes;
The plurality of permanent magnet pieces in the rotor are disposed at a predetermined distance in the circumferential direction at a predetermined distance from the center of the wheel base of the wheel.
An excitation coil of the stator includes a first excitation coil facing the one end face in the axial direction of the rotor with the gap and a second excitation coil facing the other end face in the axial direction of the rotor with the gap. With
The stator core is opposed to the first stator coil facing the other end surface of the first excitation coil facing the one end surface of the first excitation coil facing the rotor of the first excitation coil, and the rotor of the second excitation coil. A second stator core facing the other end surface of the second exciting coil facing the one end surface of the second exciting coil, and a connecting core connecting the first stator core and the second stator core through the outside of the wheel. An axial gap type electric vehicle motor characterized by this. Each of the first and second exciting coils is a strip-shaped conductor member, and has a spiral shape so that the width direction of the strip-shaped conductor member substantially coincides with the direction of the magnetic flux formed by the permanent magnet of the rotor. The motor for an axial gap type electric vehicle according to claim 1, wherein the motor is wound around. The rotor includes a magnetic piece having a magnetic property different from that of the wheel base instead of the permanent magnet piece,
Each of the first and second exciting coils is plural,
2. The axial gap type electric vehicle motor according to claim 1, wherein the plurality of first and second exciting coils are supplied with electric power so that the rotor rotates with respect to the stator by a switched reactance action. The axial gap type electric vehicle according to any one of claims 1 to 3, wherein the core of the stator is magnetically isotropic and is formed by molding soft magnetic powder. Motor.

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