JP5017045B2 - Axial gap type motor - Google Patents

Description

  The present invention relates to an axial gap type motor.

2. Description of the Related Art Conventionally, for example, a pair of stators arranged opposite to each other so as to sandwich a rotor from both sides in the rotation axis direction is provided, and a magnetic flux loop via a pair of stators is formed for a field magnetic flux generated by a permanent magnet of the rotor. A shaft gap type permanent magnet synchronous machine is known (see, for example, Patent Document 1 and Patent Document 2).
JP-A-10-271784 JP 2001-136721 A

By the way, in the permanent magnet synchronous machine according to the above-described prior art, the magnetic flux in the rotor is linearly penetrated through the rotor so as to sweep the field magnetic flux generated by the permanent magnet of the rotor between a pair of stators. The amount of leakage is reduced, and the amount of interlinkage magnetic flux interlinking the stator windings of the stator is increased.
However, in the permanent magnet generator according to the above prior art, the plurality of teeth protruding from the flat disk-shaped stator yoke in the rotation axis direction have a substantially fan-shaped rotor facing surface, and the circumferential direction of the rotor facing surface Since the width decreases from the outer side to the inner side in the radial direction, the magnetic flux density distribution in the radial direction of the magnet magnetic flux passing through the stator yoke via the teeth becomes non-uniform, for example, the radial direction is not intended. There is a possibility that the magnet magnetic flux easily passes in the direction and the desired magnetic circuit cannot be optimized.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an axial gap type motor capable of optimizing a desired magnetic circuit for magnet magnetic flux.

  In order to solve the above-described problems and achieve the object, an axial gap motor according to a first aspect of the present invention includes a rotor that can rotate around a rotation axis (for example, the rotor 11 in the embodiment), a rotation An axial gap type motor including a stator (for example, the stator 12 in the embodiment) disposed opposite to the rotor from at least one side in the axial direction, wherein the stator has an annular back yoke (for example, an implementation) And a plurality of teeth (for example, teeth 22 in the embodiment) projecting toward the rotor in the rotation axis direction at positions at predetermined intervals in the circumferential direction of the back yoke. The teeth have a substantially fan-shaped rotor facing surface (for example, the rotor facing surface 22A in the embodiment), and the circumferential width of the rotor facing surface of the teeth is a diameter. Along with reducing toward the other from one of the direction, the rotation axial thickness of the back yoke is changed to decreasing tendency toward the other from one of the radial direction.

  Furthermore, in the axial gap type motor according to the second aspect of the present invention, the rotor includes a plurality of magnet portions (for example, the main magnet pole portion 31 in the embodiment) and a rotor frame (for example, in the embodiment). A rotor frame (33), and the rotor frame has a plurality of ribs extending in the radial direction (for example, the radial ribs 34 in the embodiment) and an inner circumferential annular ring integrally connected via the ribs. A shaft portion (for example, the inner peripheral side cylindrical portion 35 in the embodiment) and an outer peripheral side annular rim portion (for example, the outer peripheral side cylindrical portion 36 in the embodiment), and in the circumferential direction, The magnet portions arranged alternately with the ribs are accommodated between the shaft portion and the rim portion, and the radial cross-sectional area of the rotor changes in an increasing tendency from the rim portion side toward the shaft portion side. ing.

  Furthermore, in the axial gap type motor according to the third aspect of the present invention, the stator is disposed in opposition to the rotation axis direction and a pair of first stators (for example, implementations) that sandwich the rotor from both sides of the rotation axis direction. And a second stator (for example, the stator 12 in the embodiment), and is accommodated between the shaft portion and the rim portion, and is disposed on both sides of the rib in the rotational axis direction. A sub-magnet portion (for example, a sub-permanent magnet piece 43 in the embodiment) and a second sub-permanent magnet piece (for example, the sub-permanent magnet piece 43 in the embodiment). For example, the auxiliary magnet part 32) in the embodiment is provided.

According to the axial gap type motor according to the first aspect, the magnetic flux in the back yoke is changed by changing the thickness of the back yoke in the rotational axis direction in accordance with the decrease in the circumferential width of the rotor facing surface of the teeth. Density is equalized, a desired magnetic circuit can be optimized, and for example, magnetic flux can be prevented from passing in an unintended direction such as a radial direction, and a desired torque can be easily secured. In addition, for example, the back yoke can be reduced in weight compared to the case where the thickness in the rotation axis direction of the back yoke is set to be constant, regardless of the decrease in the circumferential width of the rotor facing surface.
In addition, when the thickness of the back yoke in the rotational axis direction is changed in a decreasing tendency from one side to the other in the radial direction, the end surface on the outer side in the rotational axis direction moves from the outer side in the radial direction toward the inner side. It is possible to easily improve the positioning accuracy when positioning and fixing the stator in the housing by being formed in a tapered shape inclined with respect to the radial direction so as to be shifted inward in the rotation axis direction, Vibration and noise generated during operation of the axial gap motor can be reduced, the heat radiation area of the back yoke can be increased, and the rated output of the axial gap motor can be increased.

Further, according to the axial gap type motor according to the second aspect, the radial cross-sectional area of the rotor changes in an increasing tendency from the rim portion side toward the shaft portion side. The rigidity of the rotor can be improved as compared with the case where the rotor is not changed, and the occurrence of resonance (for example, thrust vibration) can be suppressed even when the rotor rotates at high speed by increasing the natural frequency of the rotor. The rotation state of can be stabilized.
In addition, the thrust generation area of the rotor can be increased, the torque that can be output can be increased, and a radial force can be generated in the magnetic attraction force of the rotor. The positioning effect can be obtained.

  Furthermore, according to the axial gap type motor according to the third aspect, the magnetic flux is appropriately generated by the magnetic lens effect by the so-called permanent magnet Halbach arrangement of the main permanent magnet piece, the first sub permanent magnet piece, and the second sub permanent magnet piece. It can be converged.

Hereinafter, an embodiment of an axial gap type motor of the present invention will be described with reference to the accompanying drawings.
The axial gap type motor 10 according to the present embodiment includes, for example, as shown in FIGS. 1 to 3, a substantially annular rotor 11 that is rotatably provided around the rotation axis O of the axial gap type motor 10, A pair of stators 12, 12 each having a plurality of stator windings that are arranged to face each other with a predetermined gap between both sides in the direction of the axis O and generate a rotating magnetic field that rotates the rotor 11; It is configured with.

  The axial gap type motor 10 is mounted as a drive source in a vehicle such as a hybrid vehicle or an electric vehicle, for example, and an output shaft is connected to an input shaft of a transmission (not shown), whereby the driving force of the axial gap type motor 10 is obtained. Is transmitted to drive wheels (not shown) of the vehicle via a transmission.

  Further, when the driving force is transmitted from the driving wheel side to the axial gap type motor 10 during deceleration of the vehicle, the axial gap type motor 10 functions as a generator to generate a so-called regenerative braking force, and the kinetic energy of the vehicle body is electrically converted. Recover as energy (regenerative energy). Further, for example, in a hybrid vehicle, when the rotating shaft of the axial gap type motor 10 is connected to the crankshaft of an internal combustion engine (not shown), the axial gap motor 10 is also axially transmitted when the output of the internal combustion engine is transmitted to the axial gap type motor 10. The gap type motor 10 functions as a generator and generates power generation energy.

  Each stator 12 protrudes toward the rotor 11 in the direction of the rotation axis O from a position at a predetermined interval in the circumferential direction on the substantially annular plate-shaped yoke portion 21 and the facing surface of the yoke portion 21 facing the rotor 11. A plurality of teeth 22,..., 22 extending in the radial direction, and a stator winding (not shown) mounted in a slot 23 between the teeth 22 adjacent to each other in the circumferential direction.

Each stator 12 is a 6N type having, for example, six main poles (for example, U ⁺ , V ⁺ , W ⁺ , U ⁻ , V ⁻ , W ⁻ ), and each stator 12 has a U ⁺ , The U ⁻ , V ⁻ , and W ⁻ poles of the other stator 12 are set to face the V ⁺ and W ⁺ poles in the direction of the rotation axis O.
For example, with respect to a pair of stators 12 and 12 facing in the direction of the rotation axis O, three stators 12 corresponding to one of U ⁺ , V ⁺ , W ⁺ poles and one of U ⁻ , V ⁻ , W ⁻ poles The teeth 22, 22, 22 and the three teeth 22, 22, 22 of the other stator 12 corresponding to the other of the U ⁺ , V ⁺ , W ⁺ pole and the other of the U ⁻ , V ⁻ , W ⁻ poles rotate. It is set so as to face each other in the direction of the axis O, and is set so that the energized state with respect to the teeth 22 of one stator 12 and the teeth 22 of the other stator 12 facing each other in the direction of the rotation axis O is reversed in electrical angle. ing.

  For example, as shown in FIG. 4, the end face on the inner side of the rotor 11 of the yoke portion 21 of each stator 12 in the direction of the rotation axis O, that is, the rotor facing surface 21A is parallel to the radial direction. The outer end surface 21B of the yoke portion 21 in the direction of the rotation axis O is a tapered shape formed by a flat surface inclined by a predetermined angle φ with respect to the radial direction, and the yoke portion 21 in the direction of the rotation axis O is formed. The thickness gradually increases from the inner side to the outer side in the radial direction, for example, from the inner peripheral side thickness La to the outer peripheral side thickness Lb (> La).

  The thicknesses of the teeth 22 of each stator 12 in the direction of the rotation axis O are the same from the inside to the outside in the radial direction (that is, the inner peripheral side thickness Ha = the outer peripheral side thickness Hb). The end surface on the rotor 11 side in the direction of the rotational axis O of 22, that is, the rotor facing surface 22 </ b> A is parallel to the radial direction.

Further, the rotor facing surface 22A of the teeth 22 is substantially fan-shaped, and the circumferential width of the rotor facing surface 22A is directed from the inner side to the outer side in the radial direction, for example, from the inner peripheral side width Ta to the outer peripheral side width Tb. It gradually increases to (> Ta).
The change ratio between the inner peripheral side thickness La and the outer peripheral side thickness Lb of the yoke part 21 and the change ratio between the inner peripheral side width Ta and the outer peripheral side width Tb of the teeth 22 are, for example, equal (La: Lb = Ta: Tb).

That is, as the circumferential width of the rotor facing surface 22A of the tooth 22 decreases from the outside in the radial direction to the inside, the thickness of the yoke portion 21 in the rotational axis O direction increases from the outside in the radial direction. It is changing toward a decreasing trend. Thereby, the magnetic flux density in the yoke part 21 is equalized, and the magnetic flux is prevented from passing in the radial direction.
It should be noted that the circumferential spacing between adjacent teeth 22 and 22 in the circumferential direction, that is, the slot width of the slot 23 formed between the adjacent teeth 22 and 22 in the circumferential direction and extending in the radial direction is the radial direction and rotational It is set to be a predetermined constant value in the direction of the axis O.

  As shown in FIG. 2, for example, the rotor 11 includes a plurality of main magnet pole portions 31,..., A plurality of sub magnet portions 32,..., 32, and a rotor frame 33 made of a nonmagnetic material. The main magnet pole portion 31 and the sub magnet portion 32 are accommodated in the rotor frame 33 in a state of being alternately arranged in the circumferential direction.

As shown in FIGS. 2 to 4, for example, the rotor frame 33 includes an inner peripheral cylindrical portion 35 and an outer periphery connected by a plurality of radial ribs 34,..., 34 arranged at predetermined intervals in the circumferential direction. It is formed in the shape of an annular plate projecting inwardly from the inner peripheral surface of the side cylindrical portion 36 and the inner peripheral side cylindrical portion 35, and is provided on an external drive shaft (for example, an input shaft of a vehicle transmission). The connection part 37 to be connected is provided.
In this embodiment, since the inner peripheral cylindrical portion 35 of the rotor frame 33 is connected to an external drive shaft, the radially inner side of the radial rib 34 is the shaft portion side, and the radial rib 34 The radially outer side is the rim portion side.
The cross-sectional shapes of the radial ribs 34 in the radial direction are the same from the outer side to the inner side in the radial direction.

For example, as shown in FIG. 5, the main magnet pole portion 31 has a substantially sector plate-shaped main permanent magnet piece 41 magnetized in the thickness direction (that is, the rotation axis O direction), and the main permanent magnet piece 41 is thickened. The main permanent magnet pieces 41 and 41 of the main magnet pole portions 31 and 31 adjacent to each other in the circumferential direction are configured to have different magnetization directions from each other. It is set to become.
The pair of magnetic members 42, 42 has a substantially sector shape in which the cross-sectional shape in the thickness direction is the same as that of the main permanent magnet piece 41.

The plurality of main magnet pole portions 31,..., 31 accommodated in the rotor frame 33 are sandwiched by the inner peripheral cylindrical portion 35 and the outer peripheral cylindrical portion 36 from both sides in the radial direction, and also in the radial direction. The ribs 34 are arranged adjacent to each other in the circumferential direction.
In the rotor frame 33, the main permanent magnet piece 41 of each main magnet pole portion 31 is sandwiched from both sides in the circumferential direction by two radial ribs 34, and the thickness of the main permanent magnet piece 41 in the rotation axis O direction is: Similar to the radial rib 34, the radial direction is directed from the outside to the inside, and is equivalent (that is, the outer peripheral side thickness Wb = the inner peripheral side thickness Wa).
Further, the thickness of the magnetic member 42 in the direction of the rotation axis O is the same from the inner side to the outer side in the radial direction (that is, the inner peripheral side thickness Ma = the outer peripheral side thickness Mb).

The sub-magnet portion 32 includes a pair of sub-permanent magnet pieces 43 and 43 that sandwich the radial ribs 34 from both sides in the direction of the rotation axis O in the rotor frame 33, and a pair of opposed permanent magnet portions 43 facing each other in the direction of the rotation axis O The sub permanent magnet pieces 43 and 43 are magnetized in a direction (substantially circumferential direction) perpendicular to the rotation axis O direction and the radial direction, respectively, and the magnetization directions are different from each other.
The thickness of the auxiliary permanent magnet piece 43 in the direction of the rotation axis O is the same from the inner side to the outer side in the radial direction (that is, the inner peripheral side thickness Ma = the outer peripheral side thickness Mb), and The circumferential width of the sub permanent magnet piece 43 is the same (that is, the inner circumferential side width Xa = the outer circumferential side width Xb) from the inner side to the outer side in the radial direction.
In the rotor frame 33, the sub permanent magnet pieces 43 and 43 of the sub magnet portions 32 and 32 adjacent in the circumferential direction sandwich the magnetic member 42 of the main magnet pole portion 31 from both sides in the circumferential direction. In addition, the sub permanent magnet piece 43 and the magnetic member 42 are made into the substantially rectangular shape where the cross-sectional shape with respect to the circumferential direction is mutually equivalent.

  In FIG. 2, which shows the rotor frame 33 of the rotor 11 and the components other than the rotor frame 33 (that is, the main magnet pole portion 31 and the sub magnet portion 32) separated from each other, a pair facing each other in the direction of the rotation axis O. A space portion 34a in which the radial rib 34 of the rotor frame 33 is disposed is formed between the sub permanent magnet pieces 43, 43 and between the main permanent magnet pieces 41, 41 adjacent in the circumferential direction.

The pair of sub permanent magnet pieces 43, 43 facing each other in the circumferential direction via the magnetic member 42 have different magnetization directions.
The pair of sub permanent magnet pieces 43 and 43 arranged on one side in the direction of the rotation axis O have the same polarity as the magnetic pole on one side of the main permanent magnet piece 41 magnetized in the direction of the rotation axis O. A pair of sub-permanent magnet pieces 43, 43 that are opposed to each other and arranged on the other side in the direction of the rotation axis O are magnetic poles having the same polarity as the magnetic pole on the other side of the main permanent magnet piece 41 magnetized in the direction of the rotation axis O. Are arranged to face each other.

That is, for example, with respect to the main permanent magnet piece 41 in which one side in the rotation axis O direction is an N pole and the other side is an S pole, a pair of magnetic members 42 are sandwiched from both sides in the circumferential direction on one side in the rotation axis O direction. The sub permanent magnet pieces 43, 43 are arranged so that their N poles face each other in the circumferential direction, and a pair of sub permanent magnet pieces 43 sandwiching the magnetic member 42 from both sides in the circumferential direction on the other side in the rotation axis O direction. , 43 are arranged so that their S poles face each other in the circumferential direction.
Accordingly, the magnetic fluxes of the main permanent magnet piece 41 and the sub permanent magnet pieces 43 and 43 are converged by the magnetic lens effect due to the so-called permanent magnet Halbach arrangement, and the effective magnetic flux linked to the stators 12 and 12 is relatively relative to each other. It is going to increase.

In this embodiment, the radial ribs 34 of the rotor frame 33 and the main permanent magnet pieces 41 of the main magnet pole portions 31 have the same thickness in the direction of the rotation axis O from the outer side to the inner side in the radial direction. That is, with the outer peripheral side thickness Wb = inner peripheral side thickness W), the width Za in the rotation axis O direction of the inner peripheral cylindrical portion 35 of the rotor frame 33 is equal to that of the outer peripheral cylindrical portion 36. This is equivalent to the width Zb in the direction of the rotation axis O.
In other words, the radial cross-sectional area of the rotor 11 is a predetermined constant value between the inner circumferential side cylindrical portion 35 and the outer circumferential side cylindrical portion 36 of the rotor frame 33, and is directed from the radially outer side toward the inner side. It is said to be unchanged.

The rotor 11 and the pair of stators 12 and 12 are accommodated in a housing 50 as shown in FIG. 3, for example.
The housing 50 includes, for example, a pair of axial wall portions 51 and 51 that sandwich the pair of stators 12 and 12 from both sides in the rotation axis O direction, and each axial wall portion 51 is, for example, a yoke portion of each stator 12. 21 is provided with a plurality of through holes 51a that face the plurality of bolt mounting holes 21a provided on the end surface 21B of the 21 and penetrate the axial wall 51 in the direction of the rotation axis O, and are attached to the respective through holes 51a. Each stator 12 and the axial direction wall part 51 are being fixed by fastening the front-end | tip part of the volt | bolt 52a to the volt | bolt mounting hole 21a.

  The inner surface 51A of the axial wall portion 51 (that is, the stator facing surface) 51A is a taper shape formed of a flat surface inclined by a predetermined angle φ with respect to the shape along the shape of the end surface 21B of the yoke portion 21 of the stator 12. And is in surface contact with the end face 21B.

  In addition, a rotation shaft portion support hole portion that rotatably supports a rotation shaft portion (output shaft) 52 connected to the connection portion 37 of the rotor frame 33 by a bolt 52 a on the axial wall portion 51 via a bearing 53. 54 is provided.

  As described above, according to the axial gap type motor 10 according to the present embodiment, the yoke portion 21 corresponds to the decrease in the circumferential width of the rotor facing surface 22A of the tooth 22 from the radially outer side to the inner side. The magnetic flux density distribution in the radial direction of the magnetic flux passing through the yoke portion 21 through the teeth 22 is equalized by changing the thickness in the direction of the rotation axis O of the magnetic flux O to optimize the desired magnetic circuit. For example, the magnet magnetic flux can be prevented from passing in an unintended direction such as the radial direction in the yoke portion 21, and a desired torque can be easily secured. In addition, for example, compared to the case in which the thickness of the yoke portion 21 in the direction of the rotation axis O is set to be constant regardless of the decrease in the circumferential width of the rotor facing surface 22A from the outside toward the inside in the radial direction, 21 can be reduced in weight.

Further, when the thickness of the yoke portion 21 in the direction of the rotation axis O is changed in a decreasing tendency from the outside in the radial direction to the inside, the end face 21B on the outer side in the direction of the rotation axis O The surface is in contact with the end surface 21B by being formed in a tapered shape or the like that is inclined by a predetermined angle φ with respect to the radial direction so as to be displaced inward in the direction of the rotation axis O as it goes inward from the center. Positioning accuracy when the stator 12 is accommodated and fixed in the housing 50 having the tapered inner surface 51A can be easily improved, and vibration and noise generated during operation of the axial gap motor 10 can be reduced. it can.
Moreover, compared to the case where the end surface 21B of the yoke portion 21 is a flat surface parallel to the radial direction, for example, the heat radiation area of the yoke portion 21 can be increased, and the rated output of the axial gap motor 10 can be increased. Can do.

  In the above-described embodiment, the radial cross-sectional area of the rotor 11 is a predetermined constant value between the inner peripheral cylindrical portion 35 and the outer peripheral cylindrical portion 36 of the rotor frame 33, and the radial direction However, the present invention is not limited to this. For example, as in the first modification shown in FIGS. 6 to 11, the radial cross-sectional area of the rotor 11 is the outer diameter in the radial direction. It may change from the side (rim part side) to the inner side (shaft part side) and increase.

  In the first modification, for example, as shown in FIGS. 9 and 10, the cross-sectional area of the radial rib 34 with respect to the radial direction changes from the outer side to the inner side in the radial direction and increases. For example, the circumferential width of the radial rib 34 is the same (that is, the inner circumferential side width Xa = the outer circumferential side width Xb) from the inner side to the outer side in the radial direction. The thickness in the direction increases from the outer side in the radial direction to the inner side, and gradually increases from the outer peripheral side thickness Wb to the inner peripheral side thickness Wa (> Wb). Then, both end surfaces of the radial rib 34 in the direction of the rotation axis O, that is, the stator facing surfaces 34A, 34A are inclined by a predetermined angle θ with respect to the radial direction.

For example, as shown in FIG. 11, the thickness of the main permanent magnet piece 41 of each main magnet pole portion 31 in the direction of the rotation axis O is the same as the radial rib 34 from the radially outer side to the inner side. On the other hand, for example, the thickness gradually increases from the outer peripheral side thickness Wb to the inner peripheral side thickness Wa (> Wb). Thereby, the end surface in the rotation axis O direction of the main permanent magnet piece 41, that is, the stator facing surface 41A is inclined by a predetermined angle θ with respect to the radial direction.
Further, the thickness of the magnetic member 42 in the direction of the rotation axis O is the same from the inner side to the outer side in the radial direction (that is, the inner peripheral side thickness Ma = the outer peripheral side thickness Mb). Both end surfaces 42A and 42A in the direction of the rotation axis O of the 42 are substantially fan-shaped equivalent to the stator facing surface 41A of the main permanent magnet piece 41, and are inclined by a predetermined angle θ with respect to the radial direction.

  Further, the thickness of the secondary permanent magnet piece 43 of the secondary magnet portion 32 in the direction of the rotation axis O is the same from the inside in the radial direction to the outside and is equivalent (that is, the inside thickness Ma = the outside thickness Mb). And the circumferential width of the secondary permanent magnet piece 43 is the same (that is, the inner circumferential width Xa = the outer circumferential width Xb) from the inner side to the outer side in the radial direction. Both end surfaces 43A, 43A of the magnet piece 43 in the direction of the rotation axis O are substantially rectangular, equivalent to the stator facing surface 34A of the radial rib 34, and are inclined by a predetermined angle θ with respect to the radial direction.

  The thickness of the radial ribs 34 of the rotor frame 33 and the main permanent magnet pieces 41 of the main magnet pole portions 31 in the direction of the rotation axis O is directed from the outer side to the inner side in the radial direction, for example, the outer peripheral side thickness. With the gradual increase from Wb to the inner peripheral side thickness Wa (> Wb), the width Za in the rotation axis O direction of the inner peripheral cylindrical portion 35 of the rotor frame 33 is set to the outer peripheral cylindrical portion. 36 is larger than the width Zb in the direction of the rotation axis O.

Accordingly, for example, as shown in FIGS. 6 to 9, the end surface on the rotor 11 side in the rotation axis O direction of the yoke portion 21 of each stator 12, that is, the rotor facing surface 21 </ b> A has a predetermined angle θ with respect to the radial direction. The thickness of the yoke portion 21 in the direction of the rotation axis O is inclined from the inner side to the outer side in the radial direction, for example, from the inner peripheral side thickness La to the outer peripheral side thickness Lb (> La ) Gradually increasing. In the first modification, the outer end surface 21B of the yoke portion 21 in the direction of the rotation axis O is tapered, for example, made of a flat surface inclined by a predetermined angle δ with respect to the rotor facing surface 21A. .
The thickness of the teeth 22 of each stator 12 in the direction of the rotation axis O is the same from the inner side to the outer side in the radial direction (ie, the inner peripheral side thickness Ha = the outer peripheral side thickness Hb). The end surface of the teeth 22 on the rotor 11 side in the direction of the rotation axis O, that is, the rotor facing surface 22A is inclined by a predetermined angle θ with respect to the radial direction.

The rotor facing surface 22A of the teeth 22 is substantially fan-shaped, and the circumferential width of the rotor facing surface 22A is directed from the inside in the radial direction to the outside, for example, from the inner peripheral side width Ta to the outer peripheral side width Tb. It gradually increases to (> Ta).
The change ratio between the inner peripheral side thickness La and the outer peripheral side thickness Lb of the yoke part 21 and the change ratio between the inner peripheral side width Ta and the outer peripheral side width Tb of the teeth 22 are, for example, equal (La: Lb = Ta: Tb).

In the first modification, the radial cross-sectional area of the rotor 11 changes from an outer side (rim portion side) in the radial direction toward an inner side (shaft portion side), and increases, for example. Compared with the case where the radial cross-sectional area of the rotor 11 is unchanged, the rigidity of the rotor 11 can be improved, and the natural frequency of the rotor 11 increases, so that the resonance occurs even when the rotor 11 rotates at high speed (for example, Generation of thrust vibration or the like) can be suppressed, and the rotation state of the rotor 11 can be stabilized.
Moreover, the rotor facing surface 22A of the teeth 22 of each stator 12, the stator facing surface 41A of the main permanent magnet piece 41, and the end surface 43A of the sub permanent magnet piece 43 are inclined by a predetermined angle θ with respect to the radial direction. Therefore, for example, compared with the case where the rotor facing surface 22A, the stator facing surface 41A, and the end surface 43A are parallel to the radial direction, thrust is generated in a state where the radial dimension of the axial gap motor 10 is unchanged. The surface area (that is, the rotor facing surface 22A, the stator facing surface 41A, and the end surface 43A) can be increased, the torque that can be output can be increased, and a radial force can be generated in the magnetic attraction force of the rotor 11. The self-centering, that is, the automatic positioning operation of the rotation shaft O (that is, the rotation shaft portion 52) can be obtained.

In the above-described embodiment and the first modification, the outer end surface 21B of the yoke portion 21 in the direction of the rotation axis O is tapered with a flat surface inclined with respect to the radial direction. Instead, for example, as in the second modification shown in FIG. 12, the end surface 21 </ b> B may be substantially tapered with a concave curved surface inclined with respect to the radial direction.
In the second modification, the positioning accuracy of the stator 12 can be further improved as compared with the case where the outer end surface 21B of the yoke portion 21 in the direction of the rotation axis O is a tapered surface. it can.

  In the above-described embodiment and the first and second modified examples, either one of the pair of stators 12 and 12 may be omitted, or the sub magnet part 32 or the pair of sub magnet parts 32 constituting the sub magnet part 32 may be omitted. Any one of the sub permanent magnet pieces 43, 43 may be omitted.

1 is an exploded perspective view of an axial gap motor according to an embodiment of the present invention. It is a disassembled perspective view of the rotor of the axial gap type motor which concerns on one Embodiment of this invention. 1 is a radial sectional view of an axial gap motor according to an embodiment of the present invention and teeth of a stator viewed from the direction of a rotation axis O. FIG. 2 is a radial sectional view of an essential part of an axial gap type motor according to an embodiment of the present invention and stator teeth as viewed from the direction of the rotation axis O. FIG. It is a principal part perspective view of the main magnet pole part and submagnet part of the axial gap type motor which concerns on one Embodiment of this invention. It is a disassembled perspective view of the axial gap type motor which concerns on the 1st modification of one Embodiment of this invention. It is a disassembled perspective view of the rotor of the axial gap type motor which concerns on the 1st modification of one Embodiment of this invention. It is radial direction sectional drawing of the axial gap type motor which concerns on the 1st modification of one Embodiment of this invention, and the teeth of the stator seen from the rotating shaft O direction. FIG. 6 is a sectional view in the radial direction of a main part of an axial gap type motor according to a first modification of one embodiment of the present invention and teeth of the stator as viewed from the direction of the rotation axis O. It is a principal part perspective view of the rotor frame of the axial gap type motor which concerns on the 1st modification of one Embodiment of this invention. It is a principal part perspective view of the main magnet pole part and submagnet part of the axial gap type motor which concerns on the 1st modification of one Embodiment of this invention. FIG. 6 is a sectional view in the radial direction of a main part of an axial gap motor according to a second modification of the embodiment of the present invention and teeth of the stator as viewed from the direction of the rotation axis O.

Explanation of symbols

10 Axial gap type motor 11 Rotor 12 Stator (stator, first stator, second stator)
21 Yoke part (back yoke)
22 Teeth 22A Rotor facing surface 31 Main magnet pole part (magnet part)
32 Sub magnet part 33 Rotor frame 34 Radial direction rib (rib)
35 Inner peripheral side cylindrical part (shaft part)
36 Outer peripheral side cylindrical part (rim part)
41 Main permanent magnet piece 43 Sub permanent magnet piece (first sub permanent magnet piece, second sub permanent magnet piece)

Claims (3)

An axial gap type motor comprising a rotor rotatable around a rotation axis and a stator disposed opposite to the rotor from at least one side in the rotation axis direction,
The stator includes an annular back yoke and a plurality of teeth protruding toward the rotor in the rotation axis direction at positions at predetermined intervals in the circumferential direction of the back yoke,
The teeth have a substantially fan-shaped rotor facing surface,
As the circumferential width of the tooth-facing surface of the teeth decreases from one radial direction to the other, the thickness of the back yoke in the rotational axis direction decreases from one radial direction to the other. An axial gap type motor characterized by that. The rotor includes a plurality of magnet portions and a rotor frame,
The rotor frame includes a plurality of ribs extending in the radial direction, an inner circumferential annular shaft portion and an outer circumferential annular rim portion that are integrally connected via the ribs,
The magnet portions arranged alternately with the ribs in the circumferential direction are accommodated between the shaft portion and the rim portion,
2. The axial gap type motor according to claim 1, wherein a radial cross-sectional area of the rotor changes in an increasing tendency from the rim portion side toward the shaft portion side. The stator includes a pair of first and second stators that are opposed to each other in the rotation axis direction and sandwich the rotor from both sides in the rotation axis direction,
A secondary magnet portion that is housed between the shaft portion and the rim portion and includes a pair of first and second secondary permanent magnet pieces disposed on both sides of the rib in the rotational axis direction; axial gap motor according to 請 Motomeko 2 you characterized.

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