JP2012210017A - Axial gap type electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an axial gap type electric motor capable of further increasing torque.SOLUTION: A pole fixing side magnetic pole piece is aligned in a circumferential direction coaxial to an output shaft, and pole fixing side opposite faces forming an N-pole and an S-pole are alternately arranged in the circumferential direction coaxial to the output shaft. A pole transition side magnetic pole piece is aligned in a circumferential direction, and passes opposite to the pole fixing side magnetic pole piece on pole transition side opposite faces 42. Magnetic poles transits on the pole transition side opposite faces 42. An electric angle of a projection image on the pole fixing side opposite faces projected on a third imaginary plane parallel to a first imaginary plane, and an electric angle of a projection image of the pole transition side opposite faces 42 projected on the third imaginary plane are set to a numeric value relationship for establishing a maximum value of an effective magnetic flux on a circumferential line coaxial to the output shaft.

Description

  The present invention relates to an axial gap type electric motor.

  For example, as shown in Patent Document 2, an axial gap type electric motor is widely known. In the axial gap type electric motor, a plurality of magnets are arranged in a circumferential direction of a circle concentric with the output shaft (hereinafter referred to as “coaxial”) in a plane orthogonal to the output shaft. A plane, that is, a pole fixing side facing surface is defined for each magnet along a first virtual plane orthogonal to the axis of the output shaft. N poles or S poles are formed on the pole fixing side facing surface. The north and south poles are alternately arranged on the rotor in the circumferential direction. The rotor is connected to the output shaft.

  In the axial gap type electric motor, a plurality of stator cores are arranged in a circumferential direction coaxial with the output shaft. Each stator core is defined with a plane, that is, a pole transition side facing surface, along a second virtual plane parallel to the first virtual plane. The pole transition side facing surface faces the pole fixing side first virtual plane. On the pole transition side facing surface, the magnetic pole changes between the N pole and the S pole by the action of the winding wound around the stator core. The rotor rotates around the axis of the output shaft according to the transition of the magnetic pole. As a result, the output shaft rotates.

JP 2004-282899 A JP 2008-131682 A

  Generally, in an electric motor, a magnet and a stator core are arranged with as little gap as possible in the circumferential direction coaxial with the output shaft. If the space is effectively utilized in this way, an increase in magnetic flux generated by the magnet and the stator core is expected. As a result, the torque of the electric motor is expected to increase.

  For example, as described in Patent Document 2, when the windings of the stator core are connected in parallel, the torque of the axial gap type electric motor is expected to be improved. In this axial gap motor, the number of stator cores is smaller than the number of magnets arranged in the circumferential direction. With such an axial gap type motor, further increase in torque is sought.

  According to some aspects of the present invention, an axial gap type electric motor that realizes further increase in torque can be provided.

  One form of the axial gap type electric motor is an output shaft and a pole fixed side opposed arrayed in a circumferential direction coaxial with the output shaft and defined along a first virtual plane perpendicular to the axis of the output shaft A plurality of pole-fixed side pole pieces, each having an N-pole or S-pole formed on the surface, and alternately arranged in the circumferential direction coaxial with the output shaft, and arranged in the circumferential direction A plurality of pole transition sides that face the first virtual plane at a pole transition side facing surface defined along a second virtual plane parallel to the first virtual plane and cause the magnetic pole to transition at the pole transition side facing surface An electrical angle of the projected image that is crossed by a circumferential line coaxial with the output shaft with respect to a projected image of the pole-fixed facing surface projected onto a third virtual plane parallel to the first virtual plane. And a projected image of the pole transition side facing surface projected onto the third virtual plane. Wherein the electrical angle of the projected image to be traversed by the circumferential line, it is set to a numerical value related to establish a maximum value of the effective magnetic flux by the circumferential line Te.

  In such an axial gap type electric motor, when the pole fixing side facing surface and the pole transition side facing surface pass each other while facing each other, the maximum value of the effective magnetic flux is established on a circumferential line coaxial with the output shaft. Increasing the effective magnetic flux increases the torque. The torque of the axial gap type motor increases.

  Further, one form of the axial gap type electric motor is a pole fixed that is arranged along an output shaft and a first virtual plane that is arranged in a circumferential direction coaxial with the output shaft and is orthogonal to the axis of the output shaft. A plurality of pole-fixed side pole pieces, each having a north pole or a south pole on a side facing surface, and alternately arranging the north pole and the south pole in a circumferential direction coaxial with the output shaft; and arranged in the circumferential direction A plurality of poles facing the first virtual plane at a pole transition side facing surface defined along a second virtual plane parallel to the first virtual plane and changing a magnetic pole at the pole transition facing surface A first pole coaxial with the output axis with respect to a projected image of the pole transition side facing surface projected onto the third virtual plane in a third virtual plane parallel to the first virtual plane. The electrical angle of the projected image that is crossed by a circumferential line is projected onto the third virtual plane. The third imaginary plane is set smaller than an angle value that establishes a maximum value of an effective magnetic flux between the projection image of the pole-fixed side facing surface and the electrical angle of the projection image crossed by the first circumferential line. Of the projected image that is crossed by a second circumferential line that is coaxial with the output axis and larger than the first circumferential line with respect to the projected image of the pole transition side facing surface projected onto the third virtual plane. The angle is an angle that establishes the maximum value of the effective magnetic flux between the electrical angle of the projected image crossed by the second circumferential line with respect to the projected image of the pole-fixed facing surface projected onto the third virtual plane. It is set larger than the value.

  Between the first circumferential line and the second circumferential line, the electrical angle of the pole fixing side facing surface and the polar transition on any circumferential line that is larger than the first circumferential line and smaller than the second circumferential line. A numerical relationship that establishes the maximum value of the effective magnetic flux between the electrical angle of the side facing surfaces can be set. As a result, when the pole fixing side facing surface and the pole transition side facing surface pass each other, the maximum value of the effective magnetic flux is established on the circumference line coaxial with the output shaft. Increasing the effective magnetic flux increases the torque. The torque of the axial gap type motor increases.

  In the axial gap type electric motor, the adjacent pole-fixed side pole pieces may be partitioned by a uniform gap from the inner diameter side to the outer diameter side. According to such a configuration, the pole-fixed side pole pieces can be arranged in the circumferential direction with as little gap as possible. For example, when the contour of the pole-fixed side pole piece is partitioned by a radial line around the axis of the output shaft, the space between the pole-fixed side pole pieces increases as the distance from the output shaft increases in the radial direction.

  Furthermore, in the axial gap type electric motor, the radial contour line of the pole fixed side facing surface may be inclined from a radial line coaxial with the output shaft. According to such an inclination, when the pole fixing side facing surface passes the pole transition side facing surface, the radial contour line of the pole fixing side facing surface is longer than the slope without the slope. Continue to intersect the radial contour. Therefore, the change of the magnetic flux which acts on the pole transition side opposing surface between adjacent pole fixing side opposing surfaces is relieved. In particular, even if the electrical angle of the pole transition side facing surface is reduced, smooth rotation can be realized.

  Furthermore, according to one aspect of the axial gap type electric motor, the output shaft is arranged in a circumferential direction coaxial with the output shaft, and is defined along a first virtual plane orthogonal to the axis of the output shaft. A plurality of first pole fixed-side pole pieces, each having an N-pole or S-pole formed on the one-pole fixed-side facing surface, and alternately arranging the N-pole and the S-pole in a circumferential direction coaxial with the output shaft; The first pole-fixing-side facing surfaces that face each other and face each other with the second pole-fixing-side facing surface defined along the second virtual plane parallel to the first virtual plane across the space. A plurality of second pole-fixed-side pole pieces that are alternately arranged with N and S poles in the circumferential direction, and arranged in the circumferential direction in the space, The first virtual transition surface facing the first pole transition side defined along a third virtual plane parallel to the virtual plane The second virtual plane is faced by a second pole transition side facing surface defined along a fourth virtual plane parallel to the second virtual plane. And a plurality of pole transition side pole pieces that change the magnetic pole in accordance with the transition of the magnetic poles of the first pole transition side facing surface at the second pole transition side facing surface parallel to the first virtual plane. An electrical angle of the projected image that is crossed by a first circumferential line coaxial with the output axis with respect to the projected image of the first pole fixed side facing surface projected onto the fifth virtual plane, and projected onto the fifth virtual plane The electrical angle of the projected image traversed by the first circumferential line with respect to the projected image of the first pole transition side facing surface is set to a numerical relationship that establishes the maximum value of the effective magnetic flux on the circumferential line. , And a projected image of the second pole fixed side facing surface projected onto the fifth virtual plane With respect to the electrical angle of the projected image traversed by the coaxial second circumferential line of the output shaft and the projected image of the second pole transition side facing surface projected onto the fifth virtual plane, the second circumferential line The electrical angle of the projected image traversed is set to a numerical relationship that establishes the maximum value of the effective magnetic flux on the second circumferential line.

  In such an axial gap type motor, when the first pole fixed side facing surface and the first pole transition side facing surface pass each other while facing each other, the maximum value of the effective magnetic flux is established on a circumferential line coaxial with the output shaft. . Similarly, when the second pole fixed side facing surface and the second pole transition side facing surface pass each other while facing each other, the maximum value of the effective magnetic flux is established on a circumference line coaxial with the output shaft. Thus, increasing the effective magnetic flux increases the torque. The torque of the axial gap type motor increases.

  Any of the above axial gap type motors can be used in an air conditioner. The axial gap type electric motor may be used, for example, for rotationally driving the blower fan. In addition, any axial gap motor can be used in a vehicle. The axial gap type electric motor may be used as a power source for a vehicle, for example. Vehicles can include, for example, electrically assisted bicycles, as well as electric motorcycles, electric vehicles, and hybrid vehicles.

  As described above, according to the present invention, an axial gap type electric motor that realizes further increase in torque is provided.

1 is a perspective view schematically showing an external appearance of an axial gap type electric motor according to an embodiment of the present invention. It is sectional drawing of the axial gap type electric motor along the plane containing the axial center of an output shaft. It is a disassembled perspective view which shows the structure of a 1st and 2nd magnet and a stator core roughly. It is an expanded view which shows the relative position of a 1st and 2nd magnet and a stator core in the circumferential direction. It is a top view which shows roughly the projection image of the 1st pole fixed side opposing surface in the virtual plane orthogonal to the axial center of an output shaft. It is a top view which shows roughly the projection image of the 1st pole transition side opposing surface in the virtual plane orthogonal to the axial center of an output shaft. It is an enlarged plan view which shows roughly the relationship between the radial direction outline of a 1st pole fixed side opposing surface, and the radial direction outline of a 1st pole transition side opposing surface. FIG. 5 is a conceptual diagram corresponding to FIG. 4 and showing the concept of short-circuiting of the magnet magnetic flux. It is the graph which linked | related the magnitude | size of the effective magnetic flux to the relationship between the electrical angle of a magnet, and the electrical angle of a stator core. It is a graph which shows the relationship between a no-load induced voltage and an electrical angle. It is a graph which shows a voltage amplitude for every order. FIG. 11 is a graph corresponding to FIG. 10 and showing the relationship between no-load induced voltage and electrical angle in a comparative example. FIG. 12 is a graph corresponding to FIG. 11 and showing the voltage amplitude for each order in the comparative example. 1 is a perspective view schematically showing an application example of an axial gap type electric motor, that is, an air conditioner. It is a perspective view which shows a cross flow fan with the indoor unit of an air conditioner. It is a side view which shows roughly the other example of an axial gap type motor, ie, an electrically assisted bicycle. It is a side view which shows roughly the structure of an electric assist unit. It is an enlarged plan view which shows roughly the relationship between the radial direction outline of a 1st pole fixed side opposing surface, and the radial direction outline of a 1st pole transition side opposing surface.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 schematically shows the external appearance of an axial gap type electric motor (hereinafter referred to as “electric motor”) 11 according to an embodiment of the present invention. The electric motor 11 includes a housing 12. The housing 12 includes a pan-shaped housing body 13 and a disk-shaped lid body 14 that closes the opening of the housing body 13. The output shaft 15 protrudes from the center of the lid body 14 in a direction orthogonal to the surface of the lid body 14. A driving force is extracted from the output shaft 15.

  As shown in FIG. 2, a stator 16 is incorporated in the housing body 13. The stator 16 is fixed to the housing body 13. The stator 16 includes a resin main body member 17. The main body member 17 also serves as the housing main body 13. A plurality of magnetic pole pieces, that is, stator cores 18 are supported on the body member 17. The stator core 18 is incorporated in the main body member 17. For such assembly, for example, integral molding may be performed in a molding die. A winding 19 is wound around each stator core 18 around an axis parallel to the axis of the output shaft 15. Winding 19 constitutes a coil.

  A first bearing 21 is incorporated in the main body member 17 of the stator 18. The output shaft 15 is coupled to the first bearing 21. The output shaft 15 is supported by the first bearing 21 so as to be rotatable around the axis. Similarly, the second bearing 22 may be supported by the lid body 14. The output shaft 15 is supported by the second bearing 22 so as to be rotatable around the axis.

  A first rotor 23 and a second rotor 24 are connected to the output shaft 15. The first rotor 23 and the second rotor 24 are fixed to the output shaft 15 with an interval in the axial direction of the output shaft 15. The first rotor 23 and the second rotor 24 include disk-shaped support members 25 and 26, respectively. Each support member 25, 26 extends along a virtual plane orthogonal to the axis of the output shaft 15. A plurality of magnetic pole pieces, that is, first magnets 27 are supported on the support member 25 of the first rotor 23. Similarly, a plurality of magnetic pole pieces, that is, second magnets 28 are supported on the support member 26 of the second rotor 24. The first and second magnets 27 and 28 may be fixed to the corresponding support members 25 and 26, respectively.

  The first magnet 27 has a first pole fixed side facing surface 27a. Each first pole-fixing-side facing surface 27 a extends in a first virtual plane 29 that is orthogonal to the axis of the output shaft 15. That is, the first pole fixed side facing surface 27a is formed in a flat surface. Similarly, a second pole fixed side facing surface 28 a is defined in the second magnet 28. The individual second pole fixed side facing surface 28 a extends in a second virtual plane 31 parallel to the first virtual plane 29. That is, the second pole fixed side facing surface 28a is formed in a flat surface. The second pole fixed side facing surface 28a is opposed to the corresponding first pole fixed side facing surface 27a across the space. The stator core 18 is disposed between the first virtual plane 29 and the second virtual plane 31.

  The stator core 18 is divided into a first pole transition side facing surface 18a and a second pole transition side facing surface 18b. Each first pole transition side facing surface 18 a extends in a third virtual plane 32 parallel to the first virtual plane 29. That is, the first pole transition side facing surface 18a is formed in a flat surface. The first pole transition side facing surface 18a is opposed to the first virtual plane 29 at a predetermined distance. In other words, a constant distance is always maintained between the first pole fixing side facing surface 27a and the first pole transition side facing surface 18a while the output shaft 15 is stationary and rotating.

  Each second pole transition side facing surface 18 b extends in a fourth virtual plane 33 parallel to the first virtual plane 29. That is, the second pole transition side facing surface 18b is formed in a plane. The second pole transition side facing surface 18b is opposed to the second virtual plane 31 at a predetermined distance. In other words, a constant distance is always maintained between the second pole fixed side facing surface 28a and the second pole transition side facing surface 18b while the output shaft 15 is stationary and rotating.

  As shown in FIG. 3, the first magnets 27 are arranged on the first rotor 23 in the circumferential direction coaxial with the output shaft 15. Here, twelve first magnets 27 are arranged at equal angular positions. The relative positional relationship between each first magnet 27 and the axis of the output shaft 15 is set to be the same. Either the N pole or the S pole is formed on each first pole fixed side facing surface 27a. N poles and S poles are alternately arranged in the circumferential direction.

  Similarly, the second magnets 28 are arranged on the second rotor 24 in the circumferential direction coaxial with the output shaft 15. Here, twelve second magnets 28 are arranged at equal angular positions. That is, the same number of second magnets 28 as the first magnets 27 are arranged. The relative positional relationship between each second magnet 27 and the axis of the output shaft 15 is set to be the same. Either the N pole or the S pole is formed on each second pole fixed side facing surface 28a. N poles and S poles are alternately arranged in the circumferential direction.

  The stator core 18 is arranged on the stator 16 in the circumferential direction coaxial with the output shaft 15. The stator core 18 is configured as a laminate of thin sheet metal materials. Here, nine stator cores 18 are arranged at equal angular positions. That is, the number of stator cores 18 is smaller than the number of first magnets 27 and the number of second magnets 28. The relative positional relationship between each first pole transition side facing surface 18a and the axis of the output shaft 15 is set to be the same. At the same time, the relative positional relationship between each second pole transition side facing surface 18b and the axis of the output shaft 15 is set to be the same.

  As shown in FIG. 4, in the axial gap type electric motor 11, the second pole fixed side facing surface 28 a of S pole is opposed to the first pole fixed side facing surface 27 a of N pole. Similarly, the second pole fixing side facing surface 28a of N pole faces the first pole fixing side facing surface 27a of S pole. When drive current flows through the winding 19, magnetic flux flows through the stator core 18. The magnetic pole of the first pole transition side facing surface 18a changes according to the direction and magnitude of the drive current. Similarly, the magnetic pole changes on the second pole transition side facing surface 18b in response to the transition of the magnetic pole on the first pole transition side facing surface 18a. On the first and second pole transition side facing surfaces 18a, 18b, for example, N poles and S poles appear alternately according to a sine wave curve. Thus, attractive force and repulsive force are sequentially generated between the first pole fixed side facing surface 27a and the first pole transition side facing surface 18a, and the second pole fixed side facing surface 28a and the second pole transition side facing surface 18b In between, attractive and repulsive forces are generated in turn. The first rotor 23 and the second rotor 24 rotate relative to the stator 16. The output shaft 15 rotates.

  Next, the shape of the first pole fixed side facing surface 27a and the shape of the first pole transition side facing surface 18a will be described in detail. 5 and 6, the projection image 41 of the first pole fixed side facing surface 27a projected on an arbitrary virtual plane parallel to the first virtual plane 29 (hereinafter referred to as “projection image virtual plane”), and the projection image A projected image 42 of the first pole transition side facing surface 18a projected onto the virtual plane is drawn. In projecting the projection images 41 and 42, the first pole fixed side facing surface 27 a and the first pole transition side facing surface 18 a may be translated in parallel to the axis of the output shaft 15. Here, when setting the contour of the first pole fixed side facing surface 27a and the contour of the first pole transition side facing surface 18a, the first circumferential line 45 coaxial with the output shaft 15 and the output in the projected image virtual plane, and the output A second circumferential line 46 that is coaxial with the shaft 15 and larger than the first circumferential line 45 is defined. As shown in FIG. 5, the electrical angle α <b> 1 is specified on the first circumferential line 45 in the projection image 41 of the first pole fixed side facing surface 27 a. Similarly, in the projection image 41 of the first pole fixing side facing surface 27a, the electrical angle α2 is specified on the second circumferential line 46. As long as the first circumferential line 45 and the second circumferential line 46 traverse the projected image 41 of the first pole fixed side facing surface 27a without interruption in at least the projected image virtual plane, the first circumferential line 45 and the second circumferential line The line 46 may be set to an arbitrary size. In addition, the sizes of the first circumferential line 45 and the second circumferential line 46 may be appropriately adjusted according to the position and shape of the projection image 42 of the first pole transition side facing surface 18a.

  As shown in FIG. 6, the electrical angle β1 is specified on the first circumferential line 45 in the projection image 42 of the first pole transition side facing surface 18a. Similarly, the electrical angle β2 is specified on the second circumferential line 46 in the projection image 42 of the first pole transition side facing surface 18a. Here, in setting the shape of the first pole transition side facing surface 18a, the electrical angle β1 is set smaller than the angle value that establishes the maximum value of the effective magnetic flux with the electrical angle α1. At the same time, in setting the shape of the first pole transition side facing surface 18a, the electrical angle β2 is set larger than the angle value that establishes the maximum value of the effective magnetic flux between the electrical angle α2. By doing so, between the first circumferential line 45 and the second circumferential line 46, the first circumferential line 45 is larger than the first circumferential line 45 and smaller than the second circumferential line 46 on the first circumferential line 45. A numerical relationship that establishes the maximum value of the effective magnetic flux is set between the electrical angle αn of the projection image 41 of the pole fixing side facing surface 27a and the electrical angle βn of the projection image 42 of the first pole transition side facing surface 18a. Can do. As a result, the maximum value of the effective magnetic flux is established between the first pole fixed side facing surface 27a and the first pole transition side facing surface 18a. Increasing the effective magnetic flux increases the torque. The torque of the axial gap type motor 11 increases. The shapes of the second pole fixed side facing surface 28a and the second pole transition side facing surface 18b may be set similarly to the first pole fixed side facing surface 27a and the first pole transition side facing surface 18a. The electrical angle β1 is set equal to the angle value that establishes the maximum value of the effective magnetic flux with the electrical angle α1, and the electrical angle β2 is set to the angle value that establishes the maximum value of the effective magnetic flux with the electrical angle α2. It may be set equal. By doing so, at least at the first circumferential line 45 and the second circumferential line 46, the electrical angle αn of the projected image 41 of the first pole fixed side facing surface 27a and the projected image 42 of the first pole transition side facing surface 18a. A numerical relationship that establishes the maximum value of the effective magnetic flux with respect to the electrical angle βn can be set.

  In the axial gap type electric motor 11, the first magnet 27 is arranged as far as possible in the circumferential direction coaxial with the output shaft 15. In such an arrangement, the gap extends in the radial direction with a constant width between the adjacent first magnets 27. As a result, in the projected image 41 of the first magnet 27, the electrical angle α2 on the second circumferential line 46 is larger than the electrical angle α1 on the first circumferential line 45. Similar to the first magnet 27, the second magnet 28 is arranged in the circumferential direction with as little gap as possible. Accordingly, similarly, the electrical angle increases toward the outer side in the radial direction in the contour of the second magnet 28.

  In addition, in this axial gap type electric motor 11, as shown in FIG. 7, the second radius of the first pole transition side facing surface 18a with respect to the first radial direction contour line 47 of the first pole fixed side facing surface 27a. The direction outline 48 is greatly inclined. Therefore, when the first pole fixing side facing surface 27a of the first magnet 27 passes the first pole transition side facing surface 18a of the stator core 18 during rotation of the first rotor 23, the first pole transition side facing surface 18a The two radial contour lines 48 continue to intersect the first radial contour line 47 of the first pole fixed side facing surface 27a for a relatively long time. That is, the action of the magnetic flux of the first pole transition side facing surface 18a gradually escapes from the magnetic field of the first pole transition side facing surface 18a and enters the magnetic field of the adjacent first pole transition side facing surface 18a. As a result, the change in magnetic flux acting on the first pole transition side facing surface 18a between the adjacent first magnets 27 is moderated. Smooth rotation is realized. Similarly, the radial contour of the second pole transition side facing surface 18b is greatly inclined with respect to the radial contour of the second pole fixing side facing surface 28a.

  Here, the angle value and the numerical relationship for establishing the maximum value of the effective magnetic flux will be described in detail. Here, the effective magnetic flux refers to a magnetic flux passing through the inside of the stator core 18 among the magnetic flux emitted from the surface of the first magnet 27 or the second magnet 28. FIG. 8 shows a general first magnet 27 and stator core 18 when the number of stator cores 18 is smaller than the number of first magnets 27. Generally, in an electric motor, a magnet and a stator core are arranged with as little gap as possible in the circumferential direction coaxial with the output shaft. If the space is effectively utilized in this way, an increase in magnetic flux generated by the magnet and the stator core is expected. As a result, the torque of the electric motor is expected to increase. However, the inventor has noticed a short circuit of the magnetic flux as shown in FIG. Then, the inventor has verified the angle value and the numerical relationship for establishing the maximum value of the effective magnetic flux by computer simulation. As a result, as shown in FIG. 9, when a specific numerical relationship is established between the electrical angle of the magnet, that is, the size in the circumferential direction, and the electrical angle of the stator core, that is, the size in the circumferential direction, the effective magnetic flux becomes the maximum value. It was found to show. For example, when the electrical angle α of the first magnet 27 and the second magnet 28 is set in the range of 156 to 180 degrees (including the limit value), the electrical angle β of the stator core 18 is in the range of 150 to 156 degrees. If set at (including the limit value), the maximum value of the effective magnetic flux can be established in the stator core 18.

  The inventor further verified the performance of the axial gap motor 11 described above based on a numerical relationship that establishes the maximum value of the effective magnetic flux. Computer simulation was used for verification. Twelve first magnets 27 and nine stator cores 18 are arranged at equal intervals in the circumferential direction. On the first pole fixing side facing surface 27a, an electrical angle of 157.68 degrees was set on the first circumferential line 45, and an electrical angle of 166.25 degrees was set on the second circumferential line 46. On the other hand, an electrical angle of 136.89 degrees is set on the first circumferential line 45 and an electrical angle of 170.60 degrees is set on the second circumferential line 46 on the first pole transition side facing surface 18a. . A no-load induced voltage of 5.5 volts was obtained as an effective value. A fundamental amplitude of 7.7 volts was obtained. An efficiency of 83.9% was obtained at a power of 349 watts. The loss was 67.1 watts. As shown in FIG. 10, a smooth sine wave waveform was obtained with no-load induced voltage. As a result of Fourier transform of this result, as shown in FIG. 11, it was confirmed that the level of the fifth-order harmonics causing the vibration was remarkably reduced.

  The inventor prepared a comparative example for verification. In this comparative example, similarly to the specific example, twelve first magnets 27 and nine stator cores 18 are arranged at equal intervals in the circumferential direction. The electrical angle on the first circumferential line 45 in the first pole fixed side facing surface 27a was set to 157.68 degrees, and the electrical angle on the second circumferential line 46 was set to 166.25 degrees. On the other hand, on the first pole transition side facing surface 18a, an electrical angle of 215.72 degrees is set on the first circumferential line 45, and an electrical angle of 220.32 degrees is set on the second circumferential line 46. . A no-load induced voltage of 5.3 volts was obtained as an effective value. A fundamental amplitude of 7.4 volts was obtained. An efficiency of 81.9% was obtained at a power of 349 watts. The loss was 76.8 watts. As shown in FIG. 12, distortion occurred in the sinusoidal waveform due to the no-load induced voltage. As a result of Fourier transform of this result, as shown in FIG. 13, an increase in the level of the fifth harmonic that causes vibration was confirmed.

  FIG. 14 schematically shows an application example of the axial gap type electric motor 11, that is, an air conditioner 51. The air conditioner 51 includes an outdoor unit 52 and an indoor unit 53. The outdoor unit 52 is installed outdoors, for example. The indoor unit 53 is installed in a room of a house, for example. The outdoor unit 52 incorporates a compressor, an expansion valve, and a first heat exchanger. A second heat exchanger is incorporated in the indoor unit 53. The compressor sends out high-temperature and high-pressure refrigerant. During the cooling operation, the high-temperature and high-pressure refrigerant is sent to the first heat exchanger before the expansion valve. The refrigerant is condensed in the first heat exchanger. The condensed refrigerant is decompressed by the expansion valve and sent to the second heat exchanger. The refrigerant is vaporized in the second heat exchanger. Thermal energy is transferred from the surrounding air to the refrigerant. Cold air is generated. The evaporated refrigerant is returned to the compressor. On the other hand, at the time of heating operation, the high-temperature and high-pressure refrigerant is sent to the second heat exchanger before the expansion valve. The refrigerant is condensed in the second heat exchanger. Thermal energy is transferred from the refrigerant to the surrounding air. Warm air is generated. The condensed refrigerant is decompressed by the expansion valve and sent to the first heat exchanger. The refrigerant is vaporized in the first heat exchanger. The vaporized refrigerant is sent to the compressor.

  As shown in FIG. 15, a cross flow fan 54 is incorporated in the indoor unit 53. The cross flow fan 54 rotates about a rotation axis extending in the horizontal direction. The axial gap type electric motor 11 is connected to the cross flow fan 54 when generating the rotation. For example, the output shaft 15 of the axial gap type electric motor 11 is arranged coaxially with the rotation shaft of the cross flow fan 54. The output shaft 15 is coupled to the cross flow fan 54. The cross flow fan 54 rotates according to the driving force of the axial gap type electric motor 11. During rotation, the cross flow fan 54 generates an air flow. The airflow travels through the second heat exchanger. Thus, in the second heat exchanger, heat energy is exchanged between the airflow and the refrigerant.

  FIG. 16 schematically shows another application example of the axial gap type electric motor 11, that is, the electric assist bicycle 61. The electrically assisted bicycle 61 includes a body frame 62. A rear wheel 63 is attached to the body frame 62 so as to be rotatable about a horizontal axis. A steering frame 64 is attached to the body frame 62 so as to be swingable about a swing shaft. The swing axis is disposed in a virtual plane orthogonal to the rotation axis of the rear wheel 63. The swing shaft is held in an inclined posture that inclines later as it moves away from the ground. A front wheel 65 is rotatably attached to the steering frame 64. The rotational axis of the front wheel 65 extends parallel to the rotational axis of the rear wheel 63 at the reference position of the steering frame 64. A handle 66 is fixed to the steering frame 64.

  A saddle 67 is fixed to the vehicle body frame 62 between the front wheel 65 and the rear wheel 63. A drive shaft 68 is rotatably supported by the body frame 62 below the saddle 67. The drive shaft 68 extends parallel to the rotation axis of the rear wheel 63. A pair of left and right pedal arms 69 are fixed to the drive shaft 68. A pedal 71 is attached to the tip of the pedal arm 69 so as to be rotatable about a rotation axis parallel to the drive shaft 68. When the driver sits on the saddle 67, the driver can place his / her feet on the left and right pedals 71, respectively.

  A large-diameter sprocket 73 is connected to the drive shaft 68. The rotation center of the large-diameter sprocket 73 coincides with the axis of the drive shaft 68. The large-diameter sprocket 73 is fixed to the drive shaft 68. A small-diameter sprocket 74 is connected to the rear wheel 63. The rotation center of the small-diameter sprocket 74 coincides with the rotation axis of the rear wheel 63. The small-diameter sprocket 74 is fixed to the rear wheel 63. A chain 75 is wound around the large-diameter sprocket 73 and the small-diameter sprocket 74. Thus, the rotation of the large-diameter sprocket 73 is transmitted to the small-diameter sprocket 74 at a predetermined reduction ratio. The pedaling force of the pedal 71 is converted into the rotation of the rear wheel 63.

  An electric assist unit 77 is connected to the large-diameter sprocket 73. As shown in FIG. 17, the axial gap type electric motor 11 is incorporated in the electric assist unit 77. The axial center of the output shaft 15 of the axial gap type electric motor 11 extends parallel to the axial center of the drive shaft 68. The rotation of the output shaft 15 is transmitted to the drive shaft 68 via the reduction gear mechanism 78. Thus, the axial gap type motor 11 compensates for the rotational force of the drive shaft 68, that is, the large-diameter sprocket 73. As a result, a sufficient driving force is transmitted to the rear wheel 63 even if the driver only applies a small pedaling force to the pedal 71. The electric assist bicycle 61 travels comfortably.

  In the axial gap type electric motor 11, as shown in FIG. 18, instead of or in addition to the inclination of the second radial contour 48 of the first pole transition side facing surface 18a, the first pole fixed side facing surface. The radial contour line 47 may be largely inclined from the radial line A coaxial with the output shaft 15 on the 27a or the second pole fixed side facing surface 28a. Preferably, the first transition side facing surface 18a and the second transition side facing surface 28b are desired to incline in the opposite direction to the radial line A with respect to the radial line A. When the first pole fixing side facing surface 27a of the first magnet 27 passes the first pole transition side facing surface 18a of the stator core 18 during rotation of the first rotor 23, the radial contour of the first pole fixing side facing surface 27a The line 47 continues to intersect the radial contour 48 of the first pole transition side facing surface 18a for a relatively long time. That is, the action of the magnetic flux on the first pole fixed side facing surface 27a gradually escapes from the magnetic field on the first pole transition side facing surface 18a and enters the magnetic field on the adjacent first pole transition side facing surface 18a. As a result, the change in magnetic flux acting on the first pole transition side facing surface 18a between the adjacent first magnets 27 is moderated. In particular, even if the electrical angle β2 is reduced on the projection image 42 of the first pole transition side facing surface 18a, smooth rotation is realized.

  The shapes of the pole fixing side facing surfaces 27a and 28a and the pole transition side facing surfaces 18a and 18b are not limited to those of the present embodiment. In setting the electrical angles α1, α2, β1, and β2, in the axial gap type electric motor 11, only one of the first rotor 23 and the second rotor 24 may be arranged. On the first pole transition side facing surface 18a and the second pole transition side facing surface 18b, the maximum value of the effective magnetic flux is established between the electrical angle βn and the electrical angle αn on the circumference over the entire range in the radial direction of the output shaft 15. The angle value to be set may be set. The axial gap type electric motor 11 can be used as a power source for electric motorcycles, electric motorcycles, electric vehicles, hybrid vehicles, and other vehicles in general in addition to electric assist bicycles.

  11 Axial gap type motor, 15 output shaft, 18 pole transition side pole piece (stator core), 18a first pole transition side facing face, 18b second pole transition side facing face, 27 pole fixed side pole piece (first magnet), 27a First pole fixed side facing surface, 28 pole fixed side pole piece (second magnet), 28a Second pole fixed side facing surface, 29 virtual plane, 31 virtual plane, 32 virtual plane, 33 virtual plane, 41 projected image, 42 projected image, 45 1st circumferential line, 46 2nd circumferential line, 51 air conditioner, 61 vehicle (electrically assisted bicycle), α1 electrical angle, α2 electrical angle, β1 electrical angle, β2 electrical angle.

Claims (7)

An output shaft;
An N-pole or an S-pole is formed on a pole-fixing-side facing surface that is arranged in a circumferential direction coaxial with the output shaft and is defined along a first virtual plane that is orthogonal to the axis of the output shaft. A plurality of pole-fixed side pole pieces that alternately arrange the N pole and the S pole in a circumferential direction coaxial with an axis;
Arranged in the circumferential direction, the pole transition side facing surface defined along a second virtual plane parallel to the first virtual plane faces the first virtual plane, and the magnetic pole is placed on the second facing surface. A plurality of pole transition side pole pieces to be changed,
An electrical angle of the projected image that is crossed by a circumferential line coaxial with the output axis with respect to a projected image of the opposed surface on the pole fixing side that is projected onto a third virtual plane parallel to the first virtual plane; The electrical angle of the projected image traversed by the circumferential line with respect to the projected image of the pole transition side facing surface projected onto a plane is set to a numerical relationship that establishes the maximum value of the effective magnetic flux on the circumferential line. An axial gap type electric motor characterized by that. An output shaft;
An N-pole or an S-pole is formed on a pole-fixing-side facing surface that is arranged in a circumferential direction coaxial with the output shaft and is defined along a first virtual plane that is orthogonal to the axis of the output shaft. A plurality of pole-fixed side pole pieces that alternately arrange the N pole and the S pole in a circumferential direction coaxial with an axis;
Arranged in the circumferential direction, the pole transition side facing surface defined along a second virtual plane parallel to the first virtual plane faces the first virtual plane, and the magnetic pole is placed on the second facing surface. A plurality of pole transition side pole pieces to be changed,
In the third virtual plane parallel to the first virtual plane, the projection traversed by a first circumferential line coaxial with the output axis with respect to the projection image of the pole transition side facing surface projected onto the third virtual plane. The electrical angle of the image is a maximum value of the effective magnetic flux between the electrical angle of the projected image traversed by the first circumferential line with respect to the projected image of the opposed surface on the pole fixing side projected onto the third virtual plane. Set to be smaller than the angle value to establish,
Within the third virtual plane, the projection image of the pole-transition-side facing surface projected onto the third virtual plane is crossed by a second circumferential line that is coaxial with the output axis and larger than the first circumferential line. The electrical angle of the projected image is the maximum effective magnetic flux between the electrical angle of the projected image traversed by the second circumferential line with respect to the projected image of the opposed surface on the pole fixing side projected onto the third virtual plane. An axial gap type electric motor characterized by being set to be larger than an angle value for establishing a value.   3. The axial gap type electric motor according to claim 2, wherein the adjacent pole-fixed side magnetic pole pieces are partitioned by a uniform gap from the inner diameter side to the outer diameter side.   The axial gap type electric motor according to claim 3, wherein a radial contour line of the opposite surface of the pole fixing side is inclined from a radial line coaxial with the output shaft. An output shaft;
Forming a north pole or a south pole on a first pole fixed side facing surface defined along a first virtual plane orthogonal to the axis of the output shaft, arranged in a circumferential direction coaxial with the output shaft; A plurality of first pole-fixed-side pole pieces that alternately arrange the N pole and the S pole in a circumferential direction coaxial with the output shaft;
The first pole fixed side facing each other facing each first pole piece with a space between the second pole fixed side facing surfaces defined along a second virtual plane parallel to the first virtual plane A plurality of second pole fixed side magnetic pole pieces that form a magnetic pole opposite to the surface, and alternately arrange N and S poles in the circumferential direction;
In the space, arranged in the circumferential direction, facing the first virtual plane at a first pole transition side facing surface defined along a third virtual plane parallel to the first virtual plane, and The magnetic pole is changed at the one-pole-transition-side facing surface, and the second-pole-facing-side facing surface defined along the fourth virtual plane parallel to the second imaginary plane is opposed to the second imaginary plane. A plurality of pole transition side pole pieces for changing the magnetic pole according to the transition of the magnetic pole of the first pole transition side facing surface at the pole transition side facing surface;
An electrical angle of the projected image crossed by a first circumferential line coaxial with the output axis with respect to the projected image of the first pole-fixed facing surface projected onto a fifth virtual plane parallel to the first virtual plane; The electrical angle of the projected image traversed by the first circumferential line with respect to the projected image of the first pole transition side facing surface projected onto the fifth virtual plane is the maximum effective magnetic flux on the first circumferential line. Set to a numeric relationship that establishes the value,
An electrical angle of the projected image that is crossed by a second circumferential line coaxial with the output axis with respect to a projected image of the second pole fixed side facing surface projected onto the fifth virtual plane, and projected onto the fifth virtual plane The electrical angle of the projected image traversed by the second circumferential line with respect to the projected image of the second pole transition side facing surface has a numerical relationship that establishes the maximum value of the effective magnetic flux on the second circumferential line. An axial gap type electric motor characterized by being set.   An air conditioner comprising the axial gap motor according to any one of claims 1 to 5.   A vehicle comprising the axial gap type electric motor according to any one of claims 1 to 5.