Patent Publication Number: US-2022239207-A1

Title: Rotary motor and robot

Description:
The present application is based on, and claims priority from JP Application Serial Number 2021-010892, filed Jan. 27, 2021, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a rotary motor and a robot. 
     2. Related Art 
     JP-A-2004-072820 discloses a radial gap motor in a Halbach array. According to the motor, a rotor includes a first sub-pole magnet in a magnetization direction along a circumferential direction between a first main pole magnet in a magnetization direction toward a rotation axis and a second main pole magnet in a magnetization direction toward a stator. The rotor includes a second sub-pole magnet in a magnetization direction inclined at 45 degrees relative to the circumferential direction between the first main pole magnet and the first sub-pole magnet. The rotor includes a third sub-pole magnet in a magnetization direction inclined at 45 degrees relative to the circumferential direction between the second main pole magnet and the first sub-pole magnet. 
     The magnetization direction of the second sub-pole magnet is an intermediate direction between the first main pole magnet and the first sub-pole magnet. The magnetization direction of the third sub-pole magnet is an intermediate direction between the second main pole magnet and the first sub-pole magnet. The first main pole magnet, the second sub-pole magnet, the first sub-pole magnet, the third sub-pole magnet, and the second main pole magnet are sequentially placed to form a magnetic circuit. 
     However, in the motor of JP-A-2004-072820, when the rotor rotates, a magnetic field where intensity transitions in a sinusoidal wave form acts on the magnets by the stator, and there is a problem that part of the sub-pole magnets is demagnetized. When demagnetized, magnetic characteristics are deteriorated and torque is lower. 
     SUMMARY 
     A rotary motor includes a stator, and a rotor rotating relative to the stator, wherein the rotor has a first main pole magnet, a first sub-pole magnet, a second main pole magnet, and a second sub-pole magnet in contact with one another, the first main pole magnet, the first sub-pole magnet, the second main pole magnet, and the second sub-pole magnet are sequentially repeatedly placed along a circumference of a rotation axis for relative rotation, a magnetization direction of the first main pole magnet is a first direction from the stator toward the rotor, a magnetization direction of the second main pole magnet is a second direction from the rotor toward the stator, magnetization directions of the first sub-pole magnet and the second sub-pole magnet are circumferential directions from the first main pole magnet toward the second main pole magnet, the first sub-pole magnet and the second sub-pole magnet have recessed portions in parts facing the stator and facing the first main pole magnet or the second main pole magnet, and third magnets in magnetization directions different from the first direction, the second direction, or the circumferential directions or fillers containing a magnetic material are provided in the recessed portions. 
     A robot includes the above described rotary motor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic side sectional view showing an overall configuration of a rotary motor according to a first embodiment. 
         FIG. 2  is a schematic plan view of a main part showing a configuration of a rotor. 
         FIG. 3  is a schematic side view of a main part for explanation of a configuration of a magnet. 
         FIG. 4  is a schematic side view of a main part for explanation of a configuration of a magnet according to a second embodiment. 
         FIG. 5  is a schematic side view of a main part for explanation of a configuration of a magnet according to a third embodiment. 
         FIG. 6  is a schematic side view of a main part for explanation of a configuration of a magnet according to a fourth embodiment. 
         FIG. 7  is a schematic side view of a main part for explanation of a configuration of a magnet according to a fifth embodiment. 
         FIG. 8  is a schematic side view of a main part for explanation of a configuration of a magnet according to a sixth embodiment. 
         FIG. 9  is a schematic side view of a main part for explanation of a configuration of a magnet according to a seventh embodiment. 
         FIG. 10  is a schematic side view of a main part for explanation of a configuration of a magnet according to an eighth embodiment. 
         FIG. 11  is a schematic plan view of a main part for explanation of a configuration of a magnet according to a ninth embodiment. 
         FIG. 12  is a schematic perspective view showing a configuration of a robot according to a tenth embodiment. 
         FIG. 13  is a schematic side view of a main part for explanation of a configuration of a magnet according to a related art. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     First Embodiment 
     A motor  1  as a rotary motor shown in  FIG. 1  is an axial gap motor employing a double-stator structure. The motor  1  includes a rotor  3  having an annular shape rotating around a rotation axis  2 , and a first stator  4  as a stator and a second stator  5  as a stator placed with the rotor  3  in between along the rotation axis  2 . The rotor  3  rotates relative to the first stator  4  and the second stator  5 . The motor  1  rotates the rotor  3  around the rotation axis  2 . 
     Directions along the rotation axis  2  are axial directions  6 . Directions along the circumference of the rotor  3  are “circumferential directions  7 ”. A direction outward along the radius of the rotor  3  is a radial direction  8 . A direction from the second stator  5  toward the first stator  4  is a downward direction  9 . A direction from the first stator  4  toward the second stator  5  is an upward direction  10 . A clockwise direction as seen in the downward direction  9  is a first circumferential direction  11 . A counterclockwise direction as seen in the downward direction  9  is a second circumferential direction  12 . 
     The rotor  3  includes a frame  13  and a permanent magnet  14  supported by the frame  13 . The permanent magnet  14  is bonded and fixed to a side of the frame  13  in the radial direction  8 . The permanent magnet  14  is a magnetized magnet. The permanent magnet  14  includes a lower part permanent magnet  15  and an upper part permanent magnet  16 . The lower part permanent magnet  15  and the upper part permanent magnet  16  overlap as seen from the axial directions  6 . The lower part permanent magnet  15  and the upper part permanent magnet  16  are bonded and fixed to each other. The lower part permanent magnet  15  is placed at the first stator  4  side and the upper part permanent magnet  16  is placed at the second stator  5  side. A lower surface  15   a  of the lower part permanent magnet  15  faces the first stator  4  and an upper surface  16   a  of the upper part permanent magnet  16  faces the second stator  5 . 
     The first stator  4  and the second stator  5  are placed to sandwich the rotor  3  from both sides in the axial directions  6 . The first stator  4  is placed in the downward direction  9  of the rotor  3  via a gap. The second stator  5  is placed in the upward direction  10  of the rotor  3  via a gap. 
     The first stator  4  has a bottom case  17  having an annular shape, a plurality of first stator cores  18 , and first coils  19  placed in the respective first stator cores  18 . The first stator cores  18  are placed in the upward direction  10  of the bottom case  17 . Note that back yokes (not shown) are provided to connect the first stator cores  18  between the plurality of first stator cores  18 . 
     The second stator  5  has a top case  20  having an annular shape, a plurality of second stator cores  21 , and second coils  22  placed in the respective second stator cores  21 . The second stator cores  21  are placed in the downward direction  9  of the top case  20 . Note that back yokes (not shown) are provided to connect the second stator cores  21  between the plurality of second stator cores  21 . 
     Next, the configuration of the first stator  4  will be explained. The first stator  4  and the second stator  5  have the same configuration as each other and, as below, the first stator  4  will be representatively explained and the explanation of the second stator  5  will be omitted. 
     The constituent material of the bottom case  17  includes e.g. a metal material such as stainless steel, aluminum alloy, magnesium alloy, and titanium alloy, a ceramics material such as alumina and zirconia, and a resin material such as engineering plastic. In addition, the constituent material of the bottom case  17  includes e.g. various fiber-reinforced plastics such as CFRP (Carbon Fiber Reinforced Plastics) and GFRP (Glass Fiber Reinforced Plastics), and fiber-reinforced composite materials such as FRC (Fiber Reinforced Ceramics) and FRM (Fiber Reinforced Metallics). 
     The constituent material of the bottom case  17  is preferably a non-magnetic material. The bottom case  17  is harder to be affected by magnetic flux and a problem of torque reduction or the like is harder to occur. The non-magnetic material refers to a material having relative magnetic permeability substantially from 0.9 to 3.0. 
     The first stator  4  has the plurality of first stator cores  18 . The first stator cores  18  are arranged at equal intervals along the circumferential directions  7 . Each first stator core  18  is formed using e.g. various magnetic materials including a stacking material of magnetic steel sheets and a green compact of magnetic powder, particularly, a soft magnetic material. 
     The respective first stator cores  18  may be fixed to the bottom case  17  by e.g. melting, adhesives, welding, or the like, or engaged with the bottom case  17  using various engagement structures. 
     The first coil  19  is wound around the outer circumference of the first stator core  18 . The first stator core  18  and the first coil  19  form an electromagnet. The first coil  19  may be a conducting wire wound around the first stator core  18  or a conducting wire is wound around a bobbin or the like in advance and fitted around the outer circumference of the first stator core  18 . 
     The motor  1  has an energizing circuit (not shown) and each first coil  19  is coupled to the energizing circuit. Each first coil  19  is energized with a predetermined cycle or predetermined pattern. For example, when a three-phase alternating current is applied to each first coil  19 , magnetic flux is generated from the electromagnet and a force acts on the facing permanent magnet  14 . The state is cyclically repeated, and the rotor  3  rotates around the rotation axis  2 . 
     The first stator  4  may be molded using a resin as a whole. By molding using a resin, the bottom case  17  and the first stator cores  18  may be fixed to each other. 
     The first stator  4  and the second stator  5  are coupled via a center case  23 . The center case  23  is located at the outside of the rotor  3  and has a cylindrical shape. 
     The bottom case  17  and the frame  13  are rotatably coupled via a cross roller bearing  24 . The cross roller bearing  24  includes an inner ring  25 , an outer ring  26 , and a roller  27 . The bottom case  17  is coupled to the inner ring  25  and the frame  13  is coupled to the outer ring  26 . The inner ring  25  and the outer ring  26  rotate relative to each other via the roller  27 . The rotor  3  is rotatably supported relative to the first stator  4  and the second stator  5 . 
       FIG. 2  is a plan view of the rotor  3  as seen in the downward direction  9 . A part of the rotor  3  having the annular shape in the circumferential directions  7  is shown in  FIG. 2 . As shown in  FIG. 2 , the rotor  3  includes the frame  13  and the permanent magnet  14 . The frame  13  has an annular shape. The constituent material of the frame  13  includes e.g. a metal material such as stainless steel, aluminum alloy, magnesium alloy, and titanium alloy, a ceramic material such as alumina and zirconia, and a resin material such as engineering plastic. In addition, the constituent material of the frame  13  includes e.g. various fiber-reinforced plastics such as CFRP (Carbon Fiber Reinforced Plastics) and GFRP (Glass Fiber Reinforced Plastics), and fiber-reinforced composite materials such as FRC (Fiber Reinforced Ceramics) and FRM (Fiber Reinforced Metallics). 
     The constituent material of the frame  13  is preferably a non-magnetic material. The frame  13  is harder to be affected by magnetic flux and a problem of torque reduction or the like is harder to occur. The non-magnetic material refers to a material having relative magnetic permeability substantially from 0.9 to 3.0. 
     The permanent magnet  14  includes, but is not limited to e.g. a neodymium magnet, a ferrite magnet, a samarium-cobalt magnet, an alnico magnet, and a bonded magnet. 
     The permanent magnet  14  is fixed to the frame  13  using e.g. an adhesive, a fastening tool, a binding tool, or the like. Or, both an adhesive and other means may be used. An adhesive or a molding resin may be placed to cover the permanent magnet  14 . 
       FIG. 3  shows the rotor  3  in  FIG. 2  as seen from the opposite direction to the radial direction  8 . As shown in  FIG. 3 , the permanent magnet  14  of the rotor  3  is placed in a Halbach magnet array. 
     The lower part permanent magnet  15  of the rotor  3  has a lower part first main magnet  28  as a first main pole magnet, a lower part first sub-magnet  29  as a first sub-pole magnet, a lower part second main magnet  31  as a second main pole magnet, and a lower part second sub-magnet  32  as a second sub-pole magnet in contact with one another. The lower part first main magnet  28 , the lower part first sub-magnet  29 , the lower part second main magnet  31 , and the lower part second sub-magnet  32  are sequentially repeatedly placed along the circumference of the rotation axis  2  for relative rotation. 
     A direction from the first stator core  18  toward the rotor  3  is a lower part first direction  33  as a first direction. A magnetization direction  41  of the lower part first main magnet  28  is the lower part first direction  33 . Arrows within the permanent magnet  14  in  FIG. 3  show the magnetization directions  41 . A direction from the rotor  3  toward the first stator core  18  is a lower part second direction  34  as a second direction. A magnetization direction  41  of the lower part second main magnet  31  is the lower part second direction  34 . The magnetization directions  41  of the lower part first sub-magnet  29  and the lower part second sub-magnet  32  are the circumferential directions  7  from the lower part first main magnet  28  toward the lower part second main magnet  31 . 
     The lower part first sub-magnet  29  and the lower part second sub-magnet  32  have recessed portions  35  in parts facing the first stator  4  and facing the lower part first main magnet  28  or the lower part second main magnet  31 . The recessed portions  35  are respectively placed in locations corresponding to corners of the lower part first sub-magnet  29  and the lower part second sub-magnet  32 . 
     The lower part permanent magnet  15  includes a lower part first auxiliary magnet  36  as a third magnet in the recessed portion  35  between the lower part first main magnet  28  and the lower part first sub-magnet  29 . The magnetization direction  41  of the lower part first auxiliary magnet  36  is a direction intermediate between the magnetization direction  41  of the lower part first main magnet  28  and the magnetization direction  41  of the lower part first sub-magnet  29 . 
     The lower part permanent magnet  15  includes a lower part second auxiliary magnet  37  as a third magnet in the recessed portion  35  between the lower part first sub-magnet  29  and the lower part second main magnet  31 . The magnetization direction  41  of the lower part second auxiliary magnet  37  is a direction intermediate between the magnetization direction  41  of the lower part first sub-magnet  29  and the magnetization direction  41  of the lower part second main magnet  31 . 
     The lower part permanent magnet  15  includes a lower part third auxiliary magnet  38  as a third magnet in the recessed portion  35  between the lower part second main magnet  31  and the lower part second sub-magnet  32 . The magnetization direction  41  of the lower part third auxiliary magnet  38  is a direction intermediate between the magnetization direction  41  of the lower part second main magnet  31  and the magnetization direction  41  of the lower part second sub-magnet  32 . 
     The lower part permanent magnet  15  includes a lower part fourth auxiliary magnet  39  as a third magnet in the recessed portion  35  between the lower part second sub-magnet  32  and the lower part first main magnet  28 . The magnetization direction  41  of the lower part fourth auxiliary magnet  39  is a direction intermediate between the magnetization direction  41  of the lower part second sub-magnet  32  and the magnetization direction  41  of the lower part first main magnet  28 . 
     The magnetization directions  41  of the lower part first auxiliary magnet  36 , the lower part second auxiliary magnet  37 , the lower part third auxiliary magnet  38 , and the lower part fourth auxiliary magnet  39  are different from the lower part first direction  33 , the lower part second direction  34 , or the circumferential directions  7 . 
     According to the configuration, part of lines of magnetic force  42  within the rotor  3  sequentially passes the lower part first main magnet  28 , the lower part first sub-magnet  29 , and the lower part second main magnet  31 . The lower part first sub-magnet  29  includes the recessed portions  35  on both sides. In the recessed portions  35 , the lower part first auxiliary magnet  36  and the lower part second auxiliary magnet  37  are placed. Accordingly, in the recessed portions  35 , the lines of magnetic force  42  pass obliquely with respect to the lower part first direction  33 , the lower part second direction  34 , and the circumferential directions  7 . 
     As shown in  FIG. 13 , without the recessed portions  35 , radii of curvature of the lines of magnetic force  42  passing from the lower part first main magnet  28  to a lower part first sub-magnet  43  are smaller. Radii of curvature of the lines of magnetic force  42  passing from the lower part first sub-magnet  43  to the lower part second main magnet  31  are smaller. In this regard, a part of the lower part first sub-magnet  43  is affected by a magnetic field applied by the first stator  4  and demagnetized. 
     As shown in  FIG. 3 , in the recessed portions  35  of the embodiment, the lines of magnetic force  42  pass obliquely with respect to the lower part first direction  33 , the lower part second direction  34 , and the circumferential directions  7 , and the radii of curvature of the lines of magnetic force  42  passing from the lower part first main magnet  28  to the lower part first sub-magnet  29  are larger. The radii of curvature of the lines of magnetic force  42  passing from the lower part first sub-magnet  29  to the lower part second main magnet  31  are larger. In this regard, demagnetization of the lower part first sub-magnet  29  may be suppressed even when the sub-magnet is affected by the magnetic field applied by the first stator  4 . 
     The lower part second sub-magnet  32  has the same effect as the lower part first sub-magnet  29 . The radii of curvature of the lines of magnetic force  42  passing from the lower part first main magnet  28  to the lower part second sub-magnet  32  are larger. The radii of curvature of the lines of magnetic force  42  passing from the lower part second sub-magnet  32  to the lower part second main magnet  31  are larger. In this regard, demagnetization of the lower part second sub-magnet  32  may be suppressed even when the sub-magnet is affected by the magnetic field applied by the first stator  4 . 
     The upper part permanent magnet  16  has the same structure as the lower part permanent magnet  15 . The upper part permanent magnet  16  of the rotor  3  has an upper part first main magnet  44  as a first main pole magnet, an upper part first sub-magnet  45  as a first sub-pole magnet, an upper part second main magnet  46  as a second main pole magnet, and an upper part second sub-magnet  47  as a second sub-pole magnet in contact with one another. The upper part first main magnet  44 , the upper part first sub-magnet  45 , the upper part second main magnet  46 , and the upper part second sub-magnet  47  are sequentially repeatedly placed along the circumference of the rotation axis  2  for relative rotation. 
     The lower part first main magnet  28  and the upper part second main magnet  46  are adjoined in the axial directions  6 . The lower part first main magnet  28  and the upper part second main magnet  46  have the same magnetization direction  41 . The lower part first sub-magnet  29  and the upper part second sub-magnet  47  are adjoined in the axial directions  6 . The lower part first sub-magnet  29  and the upper part second sub-magnet  47  have the opposite magnetization directions  41 . The lower part second main magnet  31  and the upper part first main magnet  44  are adjoined in the axial directions  6 . The lower part second main magnet  31  and the upper part first main magnet  44  have the same magnetization direction  41 . The lower part second sub-magnet  32  and the upper part first sub-magnet  45  are adjoined in the axial directions  6 . The lower part second sub-magnet  32  and the upper part first sub-magnet  45  have the opposite magnetization directions  41 . 
     A direction from the second stator core  21  toward the rotor  3  is an upper part first direction  48  as a first direction. The magnetization direction  41  of the upper part first main magnet  44  is the upper part first direction  48 . A direction from the rotor  3  toward the second stator core  21  is an upper part second direction  49  as a second direction. The magnetization direction  41  of the upper part second main magnet  46  is the upper part second direction  49 . The magnetization directions  41  of the upper part first sub-magnet  45  and the upper part second sub-magnet  47  are circumferential directions  7  from the upper part first main magnet  44  toward the upper part second main magnet  46 . 
     The upper part first sub-magnet  45  and the upper part second sub-magnet  47  have recessed portions  35  in parts facing the second stator  5  and facing the upper part first main magnet  44  or the upper part second main magnet  46 . The recessed portions  35  are respectively placed in locations corresponding to corners of the upper part first sub-magnet  45  and the upper part second sub-magnet  47 . 
     The upper part permanent magnet  16  includes an upper part first auxiliary magnet  51  as a third magnet in the recessed portion  35  between the upper part first main magnet  44  and the upper part first sub-magnet  45 . The magnetization direction  41  of the upper part first auxiliary magnet  51  is a direction intermediate between the magnetization direction  41  of the upper part first main magnet  44  and the magnetization direction  41  of the upper part first sub-magnet  45 . 
     The upper part permanent magnet  16  includes an upper part second auxiliary magnet  52  as a third magnet in the recessed portion  35  between the upper part first sub-magnet  45  and the upper part second main magnet  46 . The magnetization direction  41  of the upper part second auxiliary magnet  52  is a direction intermediate between the magnetization direction  41  of the upper part first sub-magnet  45  and the magnetization direction  41  of the upper part second main magnet  46 . 
     The upper part permanent magnet  16  includes an upper part third auxiliary magnet  53  as a third magnet in the recessed portion  35  between the upper part second main magnet  46  and the upper part second sub-magnet  47 . The magnetization direction  41  of the upper part third auxiliary magnet  53  is a direction intermediate between the magnetization direction  41  of the upper part second main magnet  46  and the magnetization direction  41  of the upper part second sub-magnet  47 . 
     The upper part permanent magnet  16  includes an upper part fourth auxiliary magnet  54  as a third magnet in the recessed portion  35  between the upper part second sub-magnet  47  and the upper part first main magnet  44 . The magnetization direction  41  of the upper part fourth auxiliary magnet  54  is a direction intermediate between the magnetization direction  41  of the upper part second sub-magnet  47  and the magnetization direction  41  of the upper part first main magnet  44 . 
     The magnetization directions  41  of the upper part first auxiliary magnet  51 , the upper part second auxiliary magnet  52 , the upper part third auxiliary magnet  53 , and the upper part fourth auxiliary magnet  54  are different from the upper part first direction  48 , the upper part second direction  49 , or the circumferential directions  7 . 
     According to the configuration, part of lines of magnetic force  42  within the rotor  3  sequentially passes the upper part first main magnet  44 , the upper part first sub-magnet  45 , and the upper part second main magnet  46 . The upper part first sub-magnet  45  includes the recessed portions  35  on both sides. In the recessed portions  35 , the upper part first auxiliary magnet  51  and the upper part second auxiliary magnet  52  are placed. Accordingly, in the recessed portions  35 , the lines of magnetic force  42  pass obliquely with respect to the upper part first direction  48 , the upper part second direction  49 , and the circumferential directions  7 . 
     Therefore, radii of curvature of the lines of magnetic force  42  passing from the upper part first main magnet  44  to the upper part first sub-magnet  45  are larger. Radii of curvature of the lines of magnetic force  42  passing from the upper part first sub-magnet  45  to the upper part second main magnet  46  are larger. In this regard, demagnetization of the upper part first sub-magnet  45  may be suppressed even when the sub-magnet is affected by a magnetic field applied by the second stator  5 . 
     The upper part second sub-magnet  47  has the same effect as the upper part first sub-magnet  45 . The radii of curvature of the lines of magnetic force  42  passing from the upper part first main magnet  44  to the upper part second sub-magnet  47  are larger. The radii of curvature of the lines of magnetic force  42  passing from the upper part second sub-magnet  47  to the upper part second main magnet  46  are larger. In this regard, demagnetization of the upper part second sub-magnet  47  may be suppressed even when the sub-magnet is affected by the magnetic field applied by the second stator  5 . Note that the motor  1  has the double-stator structure, however, the same effects may be obtained even by a single-stator structure. 
     The lower part first auxiliary magnet  36  to the lower part fourth auxiliary magnet  39  and the upper part first auxiliary magnet  51  to the upper part fourth auxiliary magnet  54  are respectively magnetized in the single directions. According to the configuration, the magnetization directions  41  of the lower part first auxiliary magnet  36  to the lower part fourth auxiliary magnet  39  and the upper part first auxiliary magnet  51  to the upper part fourth auxiliary magnet  54  are the single directions, and the lower part first auxiliary magnet  36  to the lower part fourth auxiliary magnet  39  and the upper part first auxiliary magnet  51  to the upper part fourth auxiliary magnet  54  may be respectively magnetized by single magnetization. Therefore, the motor  1  may be manufactured with higher productivity. 
     Second Embodiment 
     The embodiment is different from the first embodiment in that the shape of the recessed portion  35  is different. The same configurations as those of the first embodiment have the same signs and the overlapping explanation will be omitted. 
     As shown in  FIG. 4 , a rotor  58  of a motor  57  as a rotary motor includes a permanent magnet  59 . The permanent magnet  59  includes a lower part permanent magnet  61  and an upper part permanent magnet  62 . The lower part permanent magnet  61  corresponds to the lower part permanent magnet  15  of the first embodiment. The upper part permanent magnet  62  corresponds to the upper part permanent magnet  16  of the first embodiment. In the lower part permanent magnet  61  of the rotor  58 , the lower part first main magnet  28 , a lower part first sub-magnet  63  as a first sub-pole magnet, the lower part second main magnet  31 , and a lower part second sub-magnet  64  as a second sub-pole magnet are sequentially repeatedly placed along the circumference of the rotation axis  2  for relative rotation. The lower part first sub-magnet  63  corresponds to the lower part first sub-magnet  29  of the first embodiment. The lower part second sub-magnet  64  corresponds to the lower part second sub-magnet  32  of the first embodiment. 
     The lower part first sub-magnet  63  and the lower part second sub-magnet  64  have recessed portions  65  in parts facing the first stator  4  and facing the lower part first main magnet  28  or the lower part second main magnet  31 . The recessed portions  65  are respectively placed in locations corresponding to corners of the lower part first sub-magnet  63  and the lower part second sub-magnet  64 . 
     The lower part permanent magnet  61  includes a lower part first auxiliary magnet  66  as a third magnet in the recessed portion  65  between the lower part first main magnet  28  and the lower part first sub-magnet  63 . The lower part permanent magnet  61  includes a lower part second auxiliary magnet  67  as a third magnet in the recessed portion  65  between the lower part first sub-magnet  63  and the lower part second main magnet  31 . The lower part permanent magnet  61  includes a lower part third auxiliary magnet  68  as a third magnet in the recessed portion  65  between the lower part second main magnet  31  and the lower part second sub-magnet  64 . The lower part permanent magnet  61  includes a lower part fourth auxiliary magnet  69  as a third magnet in the recessed portion  65  between the lower part second sub-magnet  64  and the lower part first main magnet  28 . 
     The shapes of the lower part first auxiliary magnet  66 , the lower part second auxiliary magnet  67 , the lower part third auxiliary magnet  68 , and the lower part fourth auxiliary magnet  69  are triangular shapes with ones of corners placed near the upper part permanent magnet  62 . Therefore, radii of curvature of the lines of magnetic force  42  may be made smaller close to the upper part permanent magnet  62 . The lower part first auxiliary magnet  66 , the lower part second auxiliary magnet  67 , the lower part third auxiliary magnet  68 , and the lower part fourth auxiliary magnet  69  are apart from the upper part permanent magnet  62 , and the lines of magnetic force  42  in the circumferential directions  7  pass through the lower part first sub-magnet  63  and the lower part second sub-magnet  64 . 
     Also, in the upper part permanent magnet  62  of the rotor  58 , the upper part first main magnet  44 , an upper part first sub-magnet  71  as a first sub-pole magnet, the upper part second main magnet  46 , and an upper part second sub-magnet  72  as a second sub-pole magnet are sequentially repeatedly placed along the circumference of the rotation axis  2  for relative rotation. The upper part first sub-magnet  71  corresponds to the upper part first sub-magnet  45  of the first embodiment. The upper part second sub-magnet  72  corresponds to the upper part second sub-magnet  47  of the first embodiment. 
     The upper part first sub-magnet  71  and the upper part second sub-magnet  72  have recessed portions  65  in parts facing the second stator  5  and facing the upper part first main magnet  44  or the upper part second main magnet  46 . The recessed portions  65  are respectively placed in locations corresponding to corners of the upper part first sub-magnet  71  and the upper part second sub-magnet  72 . 
     The upper part permanent magnet  62  includes an upper part first auxiliary magnet  73  as a third magnet in the recessed portion  65  between the upper part first main magnet  44  and the upper part first sub-magnet  71 . The upper part permanent magnet  62  includes an upper part second auxiliary magnet  74  as a third magnet in the recessed portion  65  between the upper part first sub-magnet  71  and the upper part second main magnet  46 . The upper part permanent magnet  62  includes an upper part third auxiliary magnet  75  as a third magnet in the recessed portion  65  between the upper part second main magnet  46  and the upper part second sub-magnet  72 . The upper part permanent magnet  62  includes an upper part fourth auxiliary magnet  76  as a third magnet in the recessed portion  65  between the upper part second sub-magnet  72  and the upper part first main magnet  44 . 
     The shapes of the upper part first auxiliary magnet  73 , the upper part second auxiliary magnet  74 , the upper part third auxiliary magnet  75 , and the upper part fourth auxiliary magnet  76  are triangular shapes with ones of corners placed near the lower part permanent magnet  61 . Therefore, radii of curvature of the lines of magnetic force  42  may be made smaller close to the lower part permanent magnet  61 . The upper part first auxiliary magnet  73 , the upper part second auxiliary magnet  74 , the upper part third auxiliary magnet  75 , and the upper part fourth auxiliary magnet  76  are apart from the lower part permanent magnet  61 , and the lines of magnetic force  42  in the circumferential directions  7  pass through the upper part first sub-magnet  71  and the upper part second sub-magnet  72 . 
     Third Embodiment 
     The embodiment is different from the first embodiment in that putty containing a magnetic material is placed in the recessed portion  35 . The same configurations as those of the first embodiment have the same signs and the overlapping explanation will be omitted. 
     As shown in  FIG. 5 , a rotor  81  of a motor  79  as a rotary motor includes a permanent magnet  82 . The permanent magnet  82  includes a lower part permanent magnet  83  and an upper part permanent magnet  84 . The lower part permanent magnet  83  corresponds to the lower part permanent magnet  15  of the first embodiment. The upper part permanent magnet  84  corresponds to the upper part permanent magnet  16  of the first embodiment. In the lower part permanent magnet  83  of the rotor  81 , the lower part first main magnet  28 , the lower part first sub-magnet  29 , the lower part second main magnet  31 , and the lower part second sub-magnet  32  are sequentially repeatedly placed along the circumference of the rotation axis  2  for relative rotation. 
     The lower part first sub-magnet  29  and the lower part second sub-magnet  32  have recessed portions  35  in parts facing the first stator  4  and facing the lower part first main magnet  28  or the lower part second main magnet  31 . The recessed portions  35  are respectively placed in locations corresponding to corners of the lower part first sub-magnet  29  and the lower part second sub-magnet  32 . The lower part permanent magnet  83  includes fillers  85  containing a magnetic material in the recessed portions  35 . 
     According to the configuration, the fillers  85  containing the magnetic material are placed in the recessed portions  35 . Accordingly, in the recessed portions  35 , the lines of magnetic force  42  pass obliquely with respect to the lower part first direction  33 , the lower part second direction  34 , and the circumferential directions  7 . 
     Therefore, the radii of curvature of the lines of magnetic force  42  passing from the lower part first main magnet  28  to the lower part first sub-magnet  29  are larger. The radii of curvature of the lines of magnetic force  42  passing from the lower part first sub-magnet  29  to the lower part second main magnet  31  are larger. The radii of curvature of the lines of magnetic force  42  passing from the lower part first main magnet  28  to the lower part second sub-magnet  32  are larger. The radii of curvature of the lines of magnetic force  42  passing from the lower part second sub-magnet  32  to the lower part second main magnet  31  are larger. In this regard, demagnetization of the lower part first sub-magnet  29  may be suppressed even when the sub-magnet is affected by the magnetic field applied by the first stator  4 . In this regard, demagnetization of the lower part second sub-magnet  32  may be suppressed even when the sub-magnet is affected by the magnetic field applied by the first stator  4 . 
     In the upper part permanent magnet  84  of the rotor  81 , the upper part first main magnet  44 , the upper part first sub-magnet  45 , the upper part second main magnet  46 , and the upper part second sub-magnet  47  are sequentially repeatedly placed along the circumference of the rotation axis  2  for relative rotation. 
     The upper part first sub-magnet  45  and the upper part second sub-magnet  47  have recessed portions  35  in parts facing the second stator  5  and facing the upper part first main magnet  44  or the upper part second main magnet  46 . The recessed portions  35  are respectively placed in locations corresponding to corners of the upper part first sub-magnet  45  and the upper part second sub-magnet  47 . The upper part permanent magnet  84  includes fillers  85  containing a magnetic material in the recessed portions  35 . 
     According to the configuration, the fillers  85  containing the magnetic material are placed in the recessed portions  35 . Accordingly, in the recessed portions  35 , the lines of magnetic force  42  pass obliquely with respect to the upper part first direction  48 , the upper part second direction  49 , and the circumferential directions  7 . 
     Therefore, the radii of curvature of the lines of magnetic force  42  passing from the upper part first main magnet  44  to the upper part first sub-magnet  45  are larger. The radii of curvature of the lines of magnetic force  42  passing from the upper part first sub-magnet  45  to the upper part second main magnet  46  are larger. The radii of curvature of the lines of magnetic force  42  passing from the upper part first main magnet  44  to the upper part second sub-magnet  47  are larger. The radii of curvature of the lines of magnetic force  42  passing from the upper part second sub-magnet  47  to the upper part second main magnet  46  are larger. In this regard, demagnetization of the upper part first sub-magnet  45  may be suppressed even when the sub-magnet is affected by the magnetic field applied by the second stator  5 . In this regard, demagnetization of the upper part second sub-magnet  47  may be suppressed even when the sub-magnet is affected by the magnetic field applied by the second stator  5 . 
     The filler  85  containing the magnetic material is putty containing a soft magnetic material or a magnetic fluid. As the soft magnetic material, e.g. iron fine powder may be used. The putty may be formed using silicone or a resin material. The magnetic fluid may be formed by e.g. dispersion of iron fine powder in an oil or grease. According to the configuration, the putty containing the soft magnetic material and the magnetic fluid are materials easily deformable and the recessed portions  35  may be easily filled with the materials. Therefore, the motor  79  may be manufactured with higher productivity. 
     Fourth Embodiment 
     The embodiment is different from the first embodiment in that shapes of the auxiliary magnets and the magnetization directions  41  are different. The same configurations as those of the first embodiment have the same signs and the overlapping explanation will be omitted. 
     As shown in  FIG. 6 , a rotor  89  of a motor  88  as a rotary motor includes a permanent magnet  91 . The permanent magnet  91  includes a lower part permanent magnet  92  and an upper part permanent magnet  93 . The lower part permanent magnet  92  corresponds to the lower part permanent magnet  15  of the first embodiment. The upper part permanent magnet  93  corresponds to the upper part permanent magnet  16  of the first embodiment. In the lower part permanent magnet  92  of the rotor  89 , the lower part first main magnet  28 , a lower part first sub-magnet  94  as a first sub-pole magnet, the lower part second main magnet  31 , and a lower part second sub-magnet  95  as a second sub-pole magnet are sequentially repeatedly placed along the circumference of the rotation axis  2  for relative rotation. The lower part first sub-magnet  94  corresponds to the lower part first sub-magnet  29  of the first embodiment. The lower part second sub-magnet  95  corresponds to the lower part second sub-magnet  32  of the first embodiment. 
     The lower part first sub-magnet  94  and the lower part second sub-magnet  95  have recessed portions  96  in parts facing the first stator  4  and facing the lower part first main magnet  28  or the lower part second main magnet  31 . The recessed portions  96  are respectively placed in locations corresponding to corners of the lower part first sub-magnet  94  and the lower part second sub-magnet  95 . 
     The lower part permanent magnet  92  includes a lower part first auxiliary magnet  97  as a third magnet in the recessed portion  96  between the lower part first main magnet  28  and the lower part first sub-magnet  94 . The lower part permanent magnet  92  includes a lower part second auxiliary magnet  98  as a third magnet in the recessed portion  96  between the lower part first sub-magnet  94  and the lower part second main magnet  31 . The lower part permanent magnet  92  includes a lower part third auxiliary magnet  99  as a third magnet in the recessed portion  96  between the lower part second main magnet  31  and the lower part second sub-magnet  95 . The lower part permanent magnet  92  includes a lower part fourth auxiliary magnet  101  as a third magnet in the recessed portion  96  between the lower part second sub-magnet  95  and the lower part first main magnet  28 . 
     The shapes of the lower part first auxiliary magnet  97 , the lower part second auxiliary magnet  98 , the lower part third auxiliary magnet  99 , and the lower part fourth auxiliary magnet  101  are shapes in which rectangles elongated in the axial directions  6  and squares located in the circumferential directions  7  of the rectangles are connected. In the respective magnets, angles between the magnetization directions  41  in the parts of the rectangles elongated in the axial directions  6  and the circumferential directions  7  are about 45 degrees. In the respective magnets, angles between the magnetization directions  41  in the parts of the squares and the circumferential directions  7  are about 30 degrees. 
     The lower part first auxiliary magnet  97 , the lower part second auxiliary magnet  98 , the lower part third auxiliary magnet  99 , and the lower part fourth auxiliary magnet  101  are magnetized in pluralities of directions. According to the configuration, the respective magnets of the lower part first auxiliary magnet  97 , the lower part second auxiliary magnet  98 , the lower part third auxiliary magnet  99 , and the lower part fourth auxiliary magnet  101  are magnetized in the pluralities of directions, and radii of curvature of the lines of magnetic force  42  may be made larger. The shapes of the lines of magnetic force  42  may be made closer to shapes such that the lower part first sub-magnet  94  and the lower part second sub-magnet  95  may be harder to be demagnetized. Therefore, reduction of demagnetization of the rotor  89  may be suppressed. 
     Also, in the upper part permanent magnet  93  of the rotor  89 , the upper part first main magnet  44 , an upper part first sub-magnet  102  as a first sub-pole magnet, the upper part second main magnet  46 , and an upper part second sub-magnet  103  as a second sub-pole magnet are sequentially repeatedly placed along the circumference of the rotation axis  2  for relative rotation. The upper part first sub-magnet  102  corresponds to the upper part first sub-magnet  45  of the first embodiment. The upper part second sub-magnet  103  corresponds to the upper part second sub-magnet  47  of the first embodiment. 
     The upper part first sub-magnet  102  and the upper part second sub-magnet  103  have recessed portions  96  in parts facing the second stator  5  and facing the upper part first main magnet  44  or the upper part second main magnet  46 . The recessed portions  96  are respectively placed in locations corresponding to corners of the upper part first sub-magnet  102  and the upper part second sub-magnet  103 . 
     The upper part permanent magnet  93  includes an upper part first auxiliary magnet  104  as a third magnet in the recessed portion  96  between the upper part first main magnet  44  and the upper part first sub-magnet  102 . The upper part permanent magnet  93  includes an upper part second auxiliary magnet  105  as a third magnet in the recessed portion  96  between the upper part first sub-magnet  102  and the upper part second main magnet  46 . The upper part permanent magnet  93  includes an upper part third auxiliary magnet  106  as a third magnet in the recessed portion  96  between the upper part second main magnet  46  and the upper part second sub-magnet  103 . The upper part permanent magnet  93  includes an upper part fourth auxiliary magnet  107  as a third magnet in the recessed portion  96  between the upper part second sub-magnet  103  and the upper part first main magnet  44 . 
     The shapes of the upper part first auxiliary magnet  104 , the upper part second auxiliary magnet  105 , the upper part third auxiliary magnet  106 , and the upper part fourth auxiliary magnet  107  are shapes in which rectangles elongated in the axial directions  6  and squares located in the circumferential directions  7  of the rectangles are connected. In the respective magnets, angles between the magnetization directions  41  in the parts of the rectangles elongated in the axial directions  6  and the circumferential directions  7  are about 45 degrees. In the respective magnets, angles between the magnetization directions  41  in the parts of the squares and the circumferential directions  7  are about 30 degrees. 
     The upper part first auxiliary magnet  104 , the upper part second auxiliary magnet  105 , the upper part third auxiliary magnet  106 , and the upper part fourth auxiliary magnet  107  are magnetized in pluralities of directions. According to the configuration, the respective magnets of the upper part first auxiliary magnet  104 , the upper part second auxiliary magnet  105 , the upper part third auxiliary magnet  106 , and the upper part fourth auxiliary magnet  107  are magnetized in the pluralities of directions, and radii of curvature of the lines of magnetic force  42  may be made larger. The shapes of the lines of magnetic force  42  may be made closer to shapes such that the upper part first sub-magnet  102  and the upper part second sub-magnet  103  may be harder to be demagnetized. Therefore, reduction of demagnetization of the rotor  89  may be suppressed. 
     Fifth Embodiment 
     The embodiment is different from the fourth embodiment in that each auxiliary magnet is formed from a plurality of magnets. The same configurations as those of the fourth embodiment have the same signs and the overlapping explanation will be omitted. 
     As shown in  FIG. 7 , a rotor  112  of a motor  111  as a rotary motor includes a permanent magnet  113 . The permanent magnet  113  includes a lower part permanent magnet  114  and an upper part permanent magnet  115 . The lower part permanent magnet  114  corresponds to the lower part permanent magnet  92  of the fourth embodiment. The upper part permanent magnet  115  corresponds to the upper part permanent magnet  93  of the fourth embodiment. In the lower part permanent magnet  114  of the rotor  112 , the lower part first main magnet  28 , the lower part first sub-magnet  94 , the lower part second main magnet  31 , and the lower part second sub-magnet  95  are sequentially repeatedly placed along the circumference of the rotation axis  2  for relative rotation. 
     The lower part permanent magnet  114  includes a lower part first auxiliary magnet  116  as a third magnet in the recessed portion  96  between the lower part first main magnet  28  and the lower part first sub-magnet  94 . The lower part first auxiliary magnet  116  includes a first small magnet  116   a  and a second small magnet  116   b . The shape of the first small magnet  116   a  is a rectangle elongated in the axial directions  6 . The shape of the second small magnet  116   b  is a square along the circumferential directions  7 . An angle between the magnetization direction  41  of the first small magnet  116   a  and the circumferential directions  7  is about 45 degrees. An angle between the magnetization direction  41  of the second small magnet  116   b  and the circumferential directions  7  is about 30 degrees. 
     The lower part permanent magnet  114  includes a lower part second auxiliary magnet  117  as a third magnet in the recessed portion  96  between the lower part first sub-magnet  94  and the lower part second main magnet  31 . The lower part second auxiliary magnet  117  includes a third small magnet  117   a  and a fourth small magnet  117   b . The shape of the third small magnet  117   a  is a rectangle elongated in the axial directions  6 . The shape of the fourth small magnet  117   b  is a square along the circumferential directions  7 . An angle between the magnetization direction  41  of the third small magnet  117   a  and the circumferential directions  7  is about 45 degrees. An angle between the magnetization direction  41  of the fourth small magnet  117   b  and the circumferential directions  7  is about 30 degrees. 
     The lower part permanent magnet  114  includes a lower part third auxiliary magnet  118  as a third magnet in the recessed portion  96  between the lower part second main magnet  31  and the lower part second sub-magnet  95 . The lower part third auxiliary magnet  118  includes a fifth small magnet  118   a  and a sixth small magnet  118   b . The shape of the fifth small magnet  118   a  is a rectangle elongated in the axial directions  6 . The shape of the sixth small magnet  118   b  is a square along the circumferential directions  7 . An angle between the magnetization direction  41  of the fifth small magnet  118   a  and the circumferential directions  7  is about 45 degrees. An angle between the magnetization direction  41  of the sixth small magnet  118   b  and the circumferential directions  7  is about 30 degrees. 
     The lower part permanent magnet  114  includes a lower part fourth auxiliary magnet  119  as a third magnet in the recessed portion  96  between the lower part second sub-magnet  95  and the lower part first main magnet  28 . The lower part fourth auxiliary magnet  119  includes a seventh small magnet  119   a  and an eighth small magnet  119   b . The shape of the seventh small magnet  119   a  is a rectangle elongated in the axial directions  6 . The shape of the eighth small magnet  119   b  is a square along the circumferential directions  7 . An angle between the magnetization direction  41  of the seventh small magnet  119   a  and the circumferential directions  7  is about 45 degrees. An angle between the magnetization direction  41  of the eighth small magnet  119   b  and the circumferential directions  7  is about 30 degrees. 
     The lower part first auxiliary magnet  116 , the lower part second auxiliary magnet  117 , the lower part third auxiliary magnet  118 , and the lower part fourth auxiliary magnet  119  are respectively formed using pluralities of magnets magnetized in different directions. According to the configuration, the lower part first auxiliary magnet  116 , the lower part second auxiliary magnet  117 , the lower part third auxiliary magnet  118 , and the lower part fourth auxiliary magnet  119  respectively include the pluralities of magnets magnetized in the different directions. Accordingly, the respective auxiliary magnets have pluralities of magnetization directions, and the radii of curvature of the lines of magnetic force  42  may be made larger. The shapes of the lines of magnetic force  42  may be made closer to shapes such that the sub-pole magnets may be harder to be demagnetized. Therefore, reduction of demagnetization of the rotor  112  may be suppressed. 
     The first small magnet  116   a  to the eighth small magnet  119   b  are respectively magnetized in the single directions. Therefore, the small magnets may be manufactured more easily than in a case where a single small magnet is magnetized in a plurality of directions. 
     In the upper part permanent magnet  115  of the rotor  112 , the upper part first main magnet  44 , the upper part first sub-magnet  102 , the upper part second main magnet  46 , and the upper part second sub-magnet  103  are sequentially repeatedly placed along the circumference of the rotation axis  2  for relative rotation. 
     The upper part permanent magnet  115  includes an upper part first auxiliary magnet  121  as a third magnet in the recessed portion  96  between the upper part first main magnet  44  and the upper part first sub-magnet  102 . The upper part first auxiliary magnet  121  includes a ninth small magnet  121   a  and a 10th small magnet  121   b . The shape of the ninth small magnet  121   a  is a rectangle elongated in the axial directions  6 . The shape of the 10th small magnet  121   b  is a square along the circumferential directions  7 . An angle between the magnetization direction  41  of the ninth small magnet  121   a  and the circumferential directions  7  is about 45 degrees. An angle between the magnetization direction  41  of the 10th small magnet  121   b  and the circumferential directions  7  is about 30 degrees. 
     The upper part permanent magnet  115  includes an upper part second auxiliary magnet  122  as a third magnet in the recessed portion  96  between the upper part first sub-magnet  102  and the upper part second main magnet  46 . The upper part second auxiliary magnet  122  includes an 11th small magnet  122   a  and a 12th small magnet  122   b . The shape of the 11th small magnet  122   a  is a rectangle elongated in the axial directions  6 . The shape of the 12th small magnet  122   b  is a square along the circumferential directions  7 . An angle between the magnetization direction  41  of the 11th small magnet  122   a  and the circumferential directions  7  is about 45 degrees. An angle between the magnetization direction  41  of the 12th small magnet  122   b  and the circumferential directions  7  is about 30 degrees. 
     The upper part permanent magnet  115  includes an upper part third auxiliary magnet  123  as a third magnet in the recessed portion  96  between the upper part second main magnet  46  and the upper part second sub-magnet  103 . The upper part third auxiliary magnet  123  includes a 13th small magnet  123   a  and a 14th small magnet  123   b . The shape of the 13th small magnet  123   a  is a rectangle elongated in the axial directions  6 . The shape of the 14th small magnet  123   b  is a square along the circumferential directions  7 . An angle between the magnetization direction  41  of the 13th small magnet  123   a  and the circumferential directions  7  is about 45 degrees. An angle between the magnetization direction  41  of the 14th small magnet  123   b  and the circumferential directions  7  is about 30 degrees. 
     The upper part permanent magnet  115  includes an upper part fourth auxiliary magnet  124  as a third magnet in the recessed portion  96  between the upper part second sub-magnet  103  and the upper part first main magnet  44 . The upper part fourth auxiliary magnet  124  includes a 15th small magnet  124   a  and a 16th small magnet  124   b . The shape of the 15th small magnet  124   a  is a rectangle elongated in the axial directions  6 . The shape of the 16th small magnet  124   b  is a square along the circumferential directions  7 . An angle between the magnetization direction  41  of the 15th small magnet  124   a  and the circumferential directions  7  is about 45 degrees. An angle between the magnetization direction  41  of the 16th small magnet  124   b  and the circumferential directions  7  is about 30 degrees. 
     The upper part first auxiliary magnet  121 , the upper part second auxiliary magnet  122 , the upper part third auxiliary magnet  123 , and the upper part fourth auxiliary magnet  124  are respectively formed using pluralities of magnets magnetized in different directions. According to the configuration, the upper part first auxiliary magnet  121 , the upper part second auxiliary magnet  122 , the upper part third auxiliary magnet  123 , and the upper part fourth auxiliary magnet  124  respectively include the pluralities of magnets magnetized in the different directions. Accordingly, the respective auxiliary magnets have pluralities of magnetization directions, and the radii of curvature of the lines of magnetic force  42  may be made larger. The shapes of the lines of magnetic force  42  may be made closer to shapes such that the sub-pole magnets may be harder to be demagnetized. Therefore, reduction of demagnetization of the rotor  112  may be suppressed. 
     The ninth small magnet  121   a  to the 16th small magnet  124   b  are respectively magnetized in the single directions. Therefore, the small magnets may be manufactured more easily than in a case where a single small magnet is magnetized in a plurality of directions. 
     Sixth Embodiment 
     The embodiment is different from the first embodiment in that shapes of the auxiliary magnets and the magnetization directions  41  are different. The same configurations as those of the first embodiment have the same signs and the overlapping explanation will be omitted. 
     As shown in  FIG. 8 , a rotor  128  of a motor  127  as a rotary motor includes a permanent magnet  129 . The permanent magnet  129  includes a lower part permanent magnet  131  and an upper part permanent magnet  132 . The lower part permanent magnet  131  corresponds to the lower part permanent magnet  15  of the first embodiment. The upper part permanent magnet  132  corresponds to the upper part permanent magnet  16  of the first embodiment. In the lower part permanent magnet  131  of the rotor  128 , the lower part first main magnet  28 , a lower part first sub-magnet  133  as a first sub-pole magnet, the lower part second main magnet  31 , and a lower part second sub-magnet  134  as a second sub-pole magnet are sequentially repeatedly placed along the circumference of the rotation axis  2  for relative rotation. The lower part first sub-magnet  133  corresponds to the lower part first sub-magnet  29  of the first embodiment. The lower part second sub-magnet  134  corresponds to the lower part second sub-magnet  32  of the first embodiment. 
     The lower part first sub-magnet  133  and the lower part second sub-magnet  134  have recessed portions  135  in parts facing the first stator  4  and facing the lower part first main magnet  28  or the lower part second main magnet  31 . Further, the recessed portions  135  are respectively placed between corners of the lower part first sub-magnet  133  and the lower part second sub-magnet  134  facing the first stator  4 . 
     The lower part permanent magnet  131  includes a lower part first auxiliary magnet  136  as a third magnet in the recessed portion  135  of the lower part first sub-magnet  133 . The lower part permanent magnet  131  includes a lower part second auxiliary magnet  137  as a third magnet in the recessed portion  135  of the lower part second sub-magnet  134 . 
     The shapes of the lower part first auxiliary magnet  136  and the lower part second auxiliary magnet  137  are shapes in which rectangles elongated in the axial directions  6  and rectangles elongated in the circumferential directions  7  are connected along the lower part first main magnet  28  or the lower part second main magnet  31 . In the respective magnets, angles between the magnetization directions  41  in the parts of the rectangles elongated in the axial directions  6  and the circumferential directions  7  are about 45 degrees. Angles between the magnetization directions  41  in the parts of the rectangles elongated in the circumferential directions  7  and the circumferential directions  7  are about 0 degrees. 
     The lower part first auxiliary magnet  136  and the lower part second auxiliary magnet  137  are magnetized in pluralities of directions. According to the configuration, the respective magnets of the lower part first auxiliary magnet  136  and the lower part second auxiliary magnet  137  are magnetized in the pluralities of directions, and radii of curvature of the lines of magnetic force  42  may be made larger. The shapes of the lines of magnetic force  42  may be made closer to shapes such that the lower part first sub-magnet  133  and the lower part second sub-magnet  134  may be harder to be demagnetized. Therefore, reduction of demagnetization of the rotor  128  may be suppressed. 
     Also, in the upper part permanent magnet  132  of the rotor  128 , the upper part first main magnet  44 , an upper part first sub-magnet  138  as a first sub-pole magnet, the upper part second main magnet  46 , and an upper part second sub-magnet  139  as a second sub-pole magnet are sequentially repeatedly placed along the circumference of the rotation axis  2  for relative rotation. The upper part first sub-magnet  138  corresponds to the upper part first sub-magnet  45  of the first embodiment. The upper part second sub-magnet  139  corresponds to the upper part second sub-magnet  47  of the first embodiment. 
     The upper part first sub-magnet  138  and the upper part second sub-magnet  139  have recessed portions  135  in parts facing the second stator  5  and facing the upper part first main magnet  44  or the upper part second main magnet  46 . The recessed portions  135  are also respectively formed between corners of the upper part first sub-magnet  138  and the upper part second sub-magnet  139  facing the second stator  5 . 
     The upper part permanent magnet  132  includes an upper part first auxiliary magnet  141  as a third magnet in the recessed portion  135  of the upper part first sub-magnet  138 . The upper part permanent magnet  132  includes an upper part second auxiliary magnet  142  as a third magnet in the recessed portion  135  of the upper part second sub-magnet  139 . 
     The shapes of the upper part first auxiliary magnet  141  and the upper part second auxiliary magnet  142  are shapes in which rectangles elongated in the axial directions  6  and rectangles elongated in the circumferential directions  7  are connected along the upper part first main magnet  44  or the upper part second main magnet  46 . In the respective magnets, angles between the magnetization directions  41  in the parts of the rectangles elongated in the axial directions  6  and the circumferential directions  7  are about 45 degrees. In the respective magnets, angles between the magnetization directions  41  in the parts of the rectangles elongated in the circumferential directions  7  and the circumferential directions  7  are about 0 degrees. 
     The upper part first auxiliary magnet  141  and the upper part second auxiliary magnet  142  are magnetized in pluralities of directions. According to the configuration, the respective magnets of the upper part first auxiliary magnet  141  and the upper part second auxiliary magnet  142  are magnetized in the pluralities of directions, and radii of curvature of the lines of magnetic force  42  may be made larger. The shapes of the lines of magnetic force  42  may be made closer to shapes such that the upper part first sub-magnet  138  and the upper part second sub-magnet  139  may be harder to be demagnetized. Therefore, reduction of demagnetization of the rotor  128  may be suppressed. 
     Seventh Embodiment 
     The embodiment is different from the sixth embodiment in that each auxiliary magnet is formed from a plurality of magnets. The same configurations as those of the sixth embodiment have the same signs and the overlapping explanation will be omitted. 
     As shown in  FIG. 9 , a rotor  144  of a motor  143  as a rotary motor includes a permanent magnet  145 . The permanent magnet  145  includes a lower part permanent magnet  146  and an upper part permanent magnet  147 . The lower part permanent magnet  146  corresponds to the lower part permanent magnet  131  of the sixth embodiment. The upper part permanent magnet  147  corresponds to the upper part permanent magnet  132  of the sixth embodiment. In the lower part permanent magnet  146  of the rotor  144 , the lower part first main magnet  28 , the lower part first sub-magnet  133 , the lower part second main magnet  31 , and the lower part second sub-magnet  134  are sequentially repeatedly placed along the circumference of the rotation axis  2  for relative rotation. 
     The lower part permanent magnet  146  includes a lower part first auxiliary magnet  148  as a third magnet in the recessed portion  135  of the lower part first sub-magnet  133 . The lower part first auxiliary magnet  148  includes a first small magnet  148   a , a second small magnet  148   b , and a third small magnet  148   c . The shape of the first small magnet  148   a  is a rectangle elongated in the axial directions  6  along the lower part first main magnet  28 . The shape of the second small magnet  148   b  is a rectangle along the circumferential directions  7 . The shape of the third small magnet  148   c  is a rectangle elongated in the axial directions  6  along the lower part second main magnet  31 . Angles between the magnetization directions  41  of the first small magnet  148   a  and the third small magnet  148   c  and the circumferential directions  7  are about 45 degrees. An angle between the magnetization direction  41  of the second small magnet  148   b  and the circumferential directions  7  is about 0 degrees. 
     The lower part permanent magnet  146  includes a lower part second auxiliary magnet  149  as a third magnet in the recessed portion  135  of the lower part second sub-magnet  134 . The lower part second auxiliary magnet  149  includes a fourth small magnet  149   a , a fifth small magnet  149   b , and a sixth small magnet  149   c . The shape of the fourth small magnet  149   a  is a rectangle elongated in the axial directions  6  along the lower part second main magnet  31 . The shape of the fifth small magnet  149   b  is a rectangle along the circumferential directions  7 . The shape of the sixth small magnet  149   c  is a rectangle elongated in the axial directions  6  along the lower part first main magnet  28 . Angles between the magnetization directions  41  of the fourth small magnet  149   a  and the sixth small magnet  149   c  and the circumferential directions  7  are about 45 degrees. An angle between the magnetization direction  41  of the fifth small magnet  149   b  and the circumferential directions  7  is about 0 degrees. 
     The lower part first auxiliary magnet  148  and the lower part second auxiliary magnet  149  are respectively formed using pluralities of magnets magnetized in different directions. According to the configuration, the lower part first auxiliary magnet  148  and the lower part second auxiliary magnet  149  respectively include the pluralities of magnets magnetized in the different directions. Accordingly, there are pluralities of magnetization directions of the respective auxiliary magnets, and the radii of curvature of the lines of magnetic force  42  may be made larger. The shapes of the lines of magnetic force  42  may be made closer to shapes such that the sub-pole magnets may be harder to be demagnetized. Therefore, reduction of demagnetization of the rotor  144  may be suppressed. 
     In the upper part permanent magnet  147  of the rotor  144 , the upper part first main magnet  44 , the upper part first sub-magnet  138 , the upper part second main magnet  46 , and the upper part second sub-magnet  139  are sequentially repeatedly placed along the circumference of the rotation axis  2  for relative rotation. 
     The upper part permanent magnet  147  includes an upper part first auxiliary magnet  153  as a third magnet in the recessed portion  135  of the upper part first sub-magnet  138 . The upper part first auxiliary magnet  153  includes a seventh small magnet  153   a , an eighth small magnet  153   b , and a ninth small magnet  153   c . The shape of the seventh small magnet  153   a  is a rectangle elongated in the axial directions  6  along the upper part first main magnet  44 . The shape of the eighth small magnet  153   b  is a rectangle along the circumferential directions  7 . The shape of the ninth small magnet  153   c  is a rectangle elongated in the axial directions  6  along the upper part second main magnet  46 . Angles between the magnetization directions  41  of the seventh small magnet  153   a  and the ninth small magnet  153   c  and the circumferential directions  7  are about 45 degrees. An angle between the magnetization direction  41  of the eighth small magnet  153   b  and the circumferential directions  7  is about 0 degrees. 
     The upper part permanent magnet  147  includes an upper part second auxiliary magnet  154  as a third magnet in the recessed portion  135  of the upper part second sub-magnet  139 . The upper part second auxiliary magnet  154  includes a 10th small magnet  154   a , an 11th small magnet  154   b , and a 12th small magnet  154   c . The shape of the 10th small magnet  154   a  is a rectangle elongated in the axial directions  6  along the upper part second main magnet  46 . The shape of the 11th small magnet  154   b  is a rectangle along the circumferential directions  7 . The shape of the 12th small magnet  154   c  is a rectangle elongated in the axial directions  6  along the upper part first main magnet  44 . Angles between the magnetization directions  41  of the 10th small magnet  154   a  and the 12th small magnet  154   c  and the circumferential directions  7  are about 45 degrees. An angle between the magnetization direction  41  of the 11th small magnet  154   b  and the circumferential directions  7  is about 0 degrees. 
     The upper part first auxiliary magnet  153  and the upper part second auxiliary magnet  154  are respectively formed using pluralities of magnets magnetized in different directions. According to the configuration, the upper part first auxiliary magnet  153  and the upper part second auxiliary magnet  154  respectively include the pluralities of magnets magnetized in the different directions. Accordingly, there are pluralities of magnetization directions of the respective auxiliary magnets, and the radii of curvature of the lines of magnetic force  42  may be made larger. The shapes of the lines of magnetic force  42  may be made closer to shapes such that the sub-pole magnets may be harder to be demagnetized. Therefore, reduction of demagnetization of the rotor  144  may be suppressed. 
     The first small magnet  148   a  to the 12th small magnet  154   c  are respectively magnetized in the single directions. Therefore, the small magnets may be manufactured more easily than in a case where a single small magnet is magnetized in a plurality of directions. 
     Eighth Embodiment 
     The embodiment is different from the third embodiment in that the recessed portion includes a curved surface. The same configurations as those of the third embodiment have the same signs and the overlapping explanation will be omitted. 
     As shown in  FIG. 10 , a rotor  158  of a motor  157  as a rotary motor includes a permanent magnet  159 . The permanent magnet  159  includes a lower part permanent magnet  161  and an upper part permanent magnet  162 . The lower part permanent magnet  161  corresponds to the lower part permanent magnet  83  of the third embodiment. The upper part permanent magnet  162  corresponds to the upper part permanent magnet  84  of the third embodiment. In the lower part permanent magnet  161  of the rotor  158 , the lower part first main magnet  28 , a lower part first sub-magnet  163  as a first sub-pole magnet, the lower part second main magnet  31 , and a lower part second sub-magnet  164  as a second sub-pole magnet are sequentially repeatedly placed along the circumference of the rotation axis  2  for relative rotation. 
     The lower part first sub-magnet  163  and the lower part second sub-magnet  164  have recessed portions  165  in parts facing the first stator  4  and facing the lower part first main magnet  28  or the lower part second main magnet  31 . The recessed portions  165  are respectively placed in locations corresponding to corners of the lower part first sub-magnet  163  and the lower part second sub-magnet  164 . The lower part permanent magnet  161  includes fillers  85  containing a magnetic material in the recessed portions  165 . The recessed portion  165  of the lower part first sub-magnet  163  has an arc-shaped surface facing the center of gravity of the lower part first sub-magnet  163 . The recessed portion  165  of the lower part second sub-magnet  164  has an arc-shaped surface facing the center of gravity of the lower part second sub-magnet  164 . 
     According to the configuration, the fillers  85  containing the magnetic material are placed in the recessed portions  165 . Accordingly, in the recessed portions  165 , the lines of magnetic force  42  pass obliquely with respect to the lower part first direction  33 , the lower part second direction  34 , and the circumferential directions  7 . 
     Therefore, the radii of curvature of the lines of magnetic force  42  passing from the lower part first main magnet  28  to the lower part first sub-magnet  163  are larger. The radii of curvature of the lines of magnetic force  42  passing from the lower part first sub-magnet  163  to the lower part second main magnet  31  are larger. The radii of curvature of the lines of magnetic force  42  passing from the lower part first main magnet  28  to the lower part second sub-magnet  164  are larger. The radii of curvature of the lines of magnetic force  42  passing from the lower part second sub-magnet  164  to the lower part second main magnet  31  are larger. In this regard, demagnetization of the lower part first sub-magnet  163  and the lower part second sub-magnet  164  may be suppressed even when the sub-magnets are affected by the magnetic field applied by the first stator  4 . 
     In the upper part permanent magnet  162  of the rotor  158 , the upper part first main magnet  44 , an upper part first sub-magnet  166  as a first sub-pole magnet, the upper part second main magnet  46 , and an upper part second sub-magnet  167  as a second sub-pole magnet are sequentially repeatedly placed along the circumference of the rotation axis  2  for relative rotation. 
     The upper part first sub-magnet  166  and the upper part second sub-magnet  167  have recessed portions  165  in parts facing the second stator  5  and facing the upper part first main magnet  44  or the upper part second main magnet  46 . The recessed portions  165  are respectively placed in locations corresponding to corners of the upper part first sub-magnet  166  and the upper part second sub-magnet  167 . The upper part permanent magnet  162  includes fillers  85  containing a magnetic material in the recessed portions  165 . The recessed portion  165  of the upper part first sub-magnet  166  has an arc-shaped surface facing the center of gravity of the upper part first sub-magnet  166 . The recessed portion  165  of the upper part second sub-magnet  167  has an arc-shaped surface facing the center of gravity of the upper part second sub-magnet  167 . 
     According to the configuration, the fillers  85  containing the magnetic material are placed in the recessed portions  165 . Accordingly, in the recessed portions  165 , the lines of magnetic force  42  pass obliquely with respect to the upper part first direction  48 , the upper part second direction  49 , and the circumferential directions  7 . 
     Therefore, the radii of curvature of the lines of magnetic force  42  passing from the upper part first main magnet  44  to the upper part first sub-magnet  166  are larger. The radii of curvature of the lines of magnetic force  42  passing from the upper part first sub-magnet  166  to the upper part second main magnet  46  are larger. The radii of curvature of the lines of magnetic force  42  passing from the upper part first main magnet  44  to the upper part second sub-magnet  167  are larger. The radii of curvature of the lines of magnetic force  42  passing from the upper part second sub-magnet  167  to the upper part second main magnet  46  are larger. In this regard, demagnetization of the upper part first sub-magnet  166  may be suppressed even when the sub-magnet is affected by the magnetic field applied by the second stator  5 . In this regard, demagnetization of the upper part second sub-magnet  167  may be suppressed even when the sub-magnet is affected by the magnetic field applied by the second stator  5 . 
     Ninth Embodiment 
     The embodiment is different from the first embodiment in that the motor is a radial gap motor. The same configurations as those of the first embodiment have the same signs and the overlapping explanation will be omitted. 
     As shown in  FIG. 11 , a motor  170  as a rotary motor includes a rotor  171  having an annular shape rotating around the rotation axis  2  and a stator  173  placed at the rotation axis  2  side of the rotor  171 . The rotor  171  rotates relative to the stator  173 . The motor  170  rotates the rotor  171  around the rotation axis  2 . 
     The rotor  171  includes a permanent magnet  172 . The permanent magnet  172  of the rotor  171  has a first main pole magnet  174 , a first sub-pole magnet  175 , a second main pole magnet  176 , and a second sub-pole magnet  177  in contact with one another. The first main pole magnet  174 , the first sub-pole magnet  175 , the second main pole magnet  176 , and the second sub-pole magnet  177  are sequentially repeatedly placed along the circumference of the rotation axis  2  for relative rotation. 
     A direction from the stator  173  toward the rotor  171  is a first radial direction  178  as a first direction. The magnetization direction  41  of the first main pole magnet  174  is the first radial direction  178 . A direction from the rotor  171  toward the stator  173  is a second radial direction  179  as a second direction. The magnetization direction  41  of the second main pole magnet  176  is the second radial direction  179 . The magnetization directions  41  of the first sub-pole magnet  175  and the second sub-pole magnet  177  are circumferential directions  7  from the first main pole magnet  174  toward the second main pole magnet  176 . 
     The first sub-pole magnet  175  and the second sub-pole magnet  177  have recessed portions  181  in parts facing the stator  173  and facing the first main pole magnet  174  or the second main pole magnet  176 . The recessed portions  181  are respectively placed in locations corresponding to corners of the first sub-pole magnet  175  and the second sub-pole magnet  177 . 
     The permanent magnet  172  includes a first auxiliary magnet  182  as a third magnet in the recessed portion  181  between the first main pole magnet  174  and the first sub-pole magnet  175 . The magnetization direction  41  of the first auxiliary magnet  182  is a direction intermediate between the magnetization direction  41  of the first main pole magnet  174  and the magnetization direction  41  of the first sub-pole magnet  175 . 
     The permanent magnet  172  includes a second auxiliary magnet  183  as a third magnet in the recessed portion  181  between the first sub-pole magnet  175  and the second main pole magnet  176 . The magnetization direction  41  of the second auxiliary magnet  183  is a direction intermediate between the magnetization direction  41  of the first sub-pole magnet  175  and the magnetization direction  41  of the second main pole magnet  176 . 
     The permanent magnet  172  includes a third auxiliary magnet  184  as a third magnet in the recessed portion  181  between the second main pole magnet  176  and the second sub-pole magnet  177 . The magnetization direction  41  of the third auxiliary magnet  184  is a direction intermediate between the magnetization direction  41  of the second main pole magnet  176  and the magnetization direction  41  of the second sub-pole magnet  177 . 
     The permanent magnet  172  includes a fourth auxiliary magnet  185  as a third magnet in the recessed portion  181  between the second sub-pole magnet  177  and the first main pole magnet  174 . The magnetization direction  41  of the fourth auxiliary magnet  185  is a direction intermediate between the magnetization direction  41  of the second sub-pole magnet  177  and the magnetization direction  41  of the first main pole magnet  174 . 
     The magnetization directions  41  of the first auxiliary magnet  182 , the second auxiliary magnet  183 , the third auxiliary magnet  184 , and the fourth auxiliary magnet  185  are different from the first radial direction  178 , the second radial direction  179 , or the circumferential directions  7 . 
     According to the configuration, part of the lines of magnetic force  42  within the rotor  171  sequentially passes the first main pole magnet  174 , the first sub-pole magnet  175 , and the second main pole magnet  176 . The first sub-pole magnet  175  includes the recessed portions  181  on both sides. In the recessed portions  181 , the first auxiliary magnet  182  and the second auxiliary magnet  183  are placed. Accordingly, in the recessed portions  181 , the lines of magnetic force  42  pass obliquely with respect to the first radial direction  178 , the second radial direction  179 , and the circumferential directions  7 . 
     In the recessed portions  181 , the lines of magnetic force  42  pass obliquely with respect to the first radial direction  178 , the second radial direction  179 , and the circumferential directions  7 , and the radii of curvature of the lines of magnetic force  42  passing from the first main pole magnet  174  to the first sub-pole magnet  175  are larger. The radii of curvature of the lines of magnetic force  42  passing from the first sub-pole magnet  175  to the second main pole magnet  176  are larger. In this regard, demagnetization of the first sub-pole magnet  175  may be suppressed even when the sub-pole magnet is affected by a magnetic field applied by the stator  173 . 
     The second sub-pole magnet  177  has the same effect as the first sub-pole magnet  175 . The radii of curvature of the lines of magnetic force  42  passing from the first main pole magnet  174  to the second sub-pole magnet  177  are larger. The radii of curvature of the lines of magnetic force  42  passing from the second sub-pole magnet  177  to the second main pole magnet  176  are larger. In this regard, demagnetization of the second sub-pole magnet  177  may be suppressed even when the sub-pole magnet is affected by the magnetic field applied by the stator  173 . 
     Tenth Embodiment 
     In the embodiment, a robot including the motor described in the first embodiment to the ninth embodiment will be explained. A robot  200  shown in  FIG. 12  is used for respective work of e.g. transport, assembly, inspection, etc. of various workpieces (objects). The robot  200  has a base  201 , a robot arm  202 , and first drive unit  203  to sixth drive unit  208 . The base  201  is mounted on a horizontal floor  209 . Note that the base  201  may be mounted, not on the floor  209 , but on a wall, a ceiling, a platform, or the like. 
     The robot arm  202  includes a first arm  211 , a second arm  212 , a third arm  213 , a fourth arm  214 , a fifth arm  215 , and a sixth arm  216 . An end effector (not shown) may be detachably attached to the distal end of the sixth arm  216 , and gripping of a workpiece or the like may be performed using the end effector. The workpiece gripped by the end effector is not particularly limited to, but includes e.g. an electronic component and an electronic apparatus. In this specification, the base  201  side with reference to the sixth arm  216  is referred to as “proximal end side” and the sixth arm  216  side with reference to the base  201  is referred to as “distal end side”. The end effector is not particularly limited to, but includes a hand gripping a workpiece and a suction head suctioning a workpiece. 
     The robot  200  is a single-arm six-axis vertical articulated robot in which the base  201 , the first arm  211 , the second arm  212 , the third arm  213 , the fourth arm  214 , the fifth arm  215 , and the sixth arm  216  are sequentially coupled from the proximal end side toward the distal end side. Hereinafter, the first arm  211 , the second arm  212 , the third arm  213 , the fourth arm  214 , the fifth arm  215 , and the sixth arm  216  may be respectively referred to as “arm”. The lengths of the first arm  211  to the sixth arm  216  are respectively not particularly limited, but can be appropriately set. Note that the number of arms of the robot arm  202  may be one to five, seven, or more. Or, the robot  200  may be a scalar robot or a dual-arm robot including two or more robot arms  202 . 
     The base  201  and the first arm  211  are coupled via a first joint  217 . The first arm  211  is pivotable around a pivot axis parallel to a vertical axis as a pivot center relative to the base  201 . The first arm  211  pivots by driving of a first motor  218  and the first drive unit  203  having a reducer (not shown). The first motor  218  generates a drive force for pivoting the first arm  211 . 
     The first arm  211  and the second arm  212  are coupled via a second joint  219 . The second arm  212  is pivotable around a pivot axis parallel to a horizontal plane as a pivot center relative to the first arm  211 . The second arm  212  pivots by driving of a second motor  221  and the second drive unit  204  having a reducer (not shown). The second motor  221  generates a drive force for pivoting the second arm  212 . 
     The second arm  212  and the third arm  213  are coupled via a third joint  222 . The third arm  213  is pivotable around an axis parallel to a horizontal plane as a pivot center relative to the second arm  212 . The third arm  213  pivots by driving of a third motor  223  and the third drive unit  205  having a reducer (not shown). The third motor  223  generates a drive force for pivoting the third arm  213 . 
     The third arm  213  and the fourth arm  214  are coupled via a fourth joint  224 . The fourth arm  214  is pivotable around a pivot axis parallel to a center axis of the third arm  213  as a pivot center relative to the third arm  213 . The fourth arm  214  pivots by driving of a fourth motor  225  and the fourth drive unit  206  having a reducer (not shown). The fourth motor  225  generates a drive force for pivoting the fourth arm  214 . 
     The fourth arm  214  and the fifth arm  215  are coupled via a fifth joint  226 . The fifth arm  215  is pivotable around a pivot axis orthogonal to a center axis of the fourth arm  214  as a pivot center relative to the fourth arm  214 . The fifth arm  215  pivots by driving of a fifth motor  227  and the fifth drive unit  207  having a reducer (not shown). The fifth motor  227  generates a drive force for pivoting the fifth arm  215 . 
     The fifth arm  215  and the sixth arm  216  are coupled via a sixth joint  228 . The sixth arm  216  is pivotable around a pivot axis parallel to a center axis in the distal end portion of the fifth arm  215  as a pivot center relative to the fifth arm  215 . The sixth arm  216  pivots by driving of a sixth motor  229  and the sixth drive unit  208  having a reducer (not shown). The sixth motor  229  generates a drive force for pivoting the sixth arm  216 . 
     The rotary motor according to the above described respective embodiments is used for at least one of the first motor  218  to the sixth motor  229 . That is, the robot  200  includes the rotary motor according to the above described respective embodiments. 
     According to the configuration, the first motor  218  to the sixth motor  229  of the robot  200  are rotary motors in which demagnetization may be suppressed even when the numbers of the magnetization directions  41  of the sub-pole magnets are smaller. Therefore, the robot  200  may be a robot including rotary motors in which demagnetization may be suppressed even when the numbers of the magnetization directions  41  of the sub-pole magnets are smaller. 
     Eleventh Embodiment 
     In the rotor  171  of the above described ninth embodiment, the rotor  3  of the first embodiment is changed into a form of a radial gap motor. In addition, the rotor  58  of the second embodiment to the rotor  158  of the eighth embodiment may be changed into forms of radial gap motors. Also, in this case, the same effects as those of the respective embodiments may be obtained. 
     Twelfth Embodiment 
     In the rotor  171  of the above described ninth embodiment, the first auxiliary magnet  182  to the fourth auxiliary magnet  185  are placed in the recessed portions  181 . The fillers  85  may be placed in the recessed portions  181 . Also, in this case, demagnetization may be suppressed in the rotor  171 . 
     Thirteenth Embodiment 
     In the tenth embodiment, the example in which the rotary motor according to the above described respective embodiments is used for the first motor  218  to the sixth motor  229  of the six-axis vertical articulated robot is shown. In addition, the first motor  218  to the sixth motor  229  may be applied to an apparatus including a motor such as a scalar robot, a machine tool, an automobile, an electric railcar, or a home appliance.