Patent Publication Number: US-2019173334-A1

Title: Rotating electrical machine rotor

Description:
TECHNICAL FIELD 
     The present disclosure relates to a rotating electrical machine rotor used for a rotating electrical machine. 
     BACKGROUND ART 
     Typically, a rotating electrical machine used for, e.g., an electric motor or a power generator of a vehicle and including a stator and a rotor has been known (e.g., Patent Literature 1 and 2). The rotor of such a rotating electrical machine has multiple magnetic pole portions arranged with clearances in a circumferential direction. The magnetic pole portions protrude in a claw shape from an outer peripheral edge portion of an axial end of a rotor core along an axial direction. The magnetic pole portions are alternately magnetized to different polarities (specifically the N-pole and the S-pole) in the circumferential direction by power application to an annular field winding wound around an axial center portion. When each magnetic pole portion is magnetized, rotation of the rotor of the rotating electrical machine is controlled. 
     As described in Patent Literature 1, the rotor of the rotating electrical machine has, in some cases, a permanent magnet (i.e., an inter-pole magnet) arranged between each two adjacent magnetic pole portions in the circumferential direction. This permanent magnet is magnetized such that the polarity of a side surface facing the magnetic pole portion in the circumferential direction is the same as the polarity of the magnetic pole portion. Moreover, the permanent magnet has the function of enhancing a magnetic flux between the magnetic pole portion of the rotor and a stator core of the stator. 
     As described in Patent Literature 2, the rotor of the rotating electrical machine has, in some cases, a cylindrical outer peripheral iron core portion covering the outer periphery of the magnetic pole portions. Such a rotor provided with the outer peripheral iron core portion has a smooth outer peripheral surface of the rotor. Thus, wind noise due to irregularity of the outer peripheral surface can be reduced. Moreover, in the rotor, the multiple magnetic pole portions adjacent to each other in the circumferential direction are coupled by the outer peripheral iron core portion. Thus, in, e.g., the structure in which the permanent magnet is arranged between the magnetic pole portions as described in Patent Literature 1, an increase in deformation of the magnetic pole portion in a radial direction due to centrifugal force of the permanent magnet upon rotation of the rotor can be suppressed. 
     As described in Patent Literature 1, the rotor of the rotating electrical machine has, in some cases, a magnet holding portion configured to hold the permanent magnet. The magnet holding portion holds the permanent magnet between adjacent ones of the magnetic pole portions in the circumferential direction, and exhibits elasticity acting in a rotation direction of the rotor. The magnet holding portion is provided separately from the outer peripheral iron core portion. Moreover, the magnet holding portion is inserted between the magnetic pole portions with the permanent magnet being housed in the magnet holding portion, and thereafter, is pressed against the magnetic pole portions by elastic force. In this manner, the magnet holding portion holds the permanent magnet between the magnetic pole portions. 
     CITATION LIST 
     Patent Literature 
     [PTL 1]: JP 2010-16958 A 
     [PTL 2]: JP 2009-148057 A 
     SUMMARY OF THE INVENTION 
     Technical Problem 
     The above-described magnet holding portion includes a magnet holding portion formed from a non-magnetic body such as stainless steel. However, in a case where the magnet holding portion is formed from the non-magnetic body, magnetic resistance of a magnetic circuit passing through the permanent magnet held by the magnet holding portion is increased. In a case where it is configured such that the magnet holding portion uses the elastic force to hold the permanent magnet between the magnetic pole portions as described above, a gap might be formed between the magnet holding portion and the magnetic pole portion. Due to the presence of such a gap, the magnetic resistance of the magnetic circuit passing through the permanent magnet is also increased. 
     The present disclosure provides a rotating electrical machine rotor capable of holding a permanent magnet between magnetic pole portions using a magnet holding portion and increasing permeance of a magnetic circuit passing through the permanent magnet. 
     Solution to Problem 
     A first rotating electrical machine rotor as one aspect of the technique of the present disclosure includes multiple magnetic pole portions facing a stator in a radial direction, arranged with clearance spaces therebetween in a circumferential direction, and alternately magnetized to different polarities in the circumferential direction by power application to a field winding, permanent magnets arranged in each clearance space such that the polarity of each of side surfaces facing the magnetic pole portions in the circumferential direction is the same as the polarity of a corresponding one of the magnetic pole portions; and a tubular outer peripheral iron core portion configured to cover an outer peripheral side of the magnetic pole portions. The outer peripheral iron core portion has a tubular body portion and magnet holding portions configured to hold the permanent magnet. 
     According to this configuration, the first rotating electrical machine rotor can hold the permanent magnet between the magnetic pole portions using the magnet holding portion of the outer peripheral iron core portion. Moreover, the magnet holding portion is an iron core arranged along a surface of the permanent magnet, and closely contacts the permanent magnet. Thus, the first rotating electrical machine rotor can decrease magnetic resistance of a magnetic circuit passing through the permanent magnet as compared to a structure in which a magnet holding portion is formed from a non-magnetic body or a structure in which a large gap is formed between a permanent magnet and a magnetic pole portion. Thus, the first rotating electrical machine rotor holds the permanent magnet between the magnetic pole portions using the magnet holding portion while increasing permeance of the magnetic circuit passing through the permanent magnet. 
     In the first rotating electrical machine rotor, the magnet holding portion is formed to protrude radially inward from an inner peripheral surface of the tubular body portion while gripping the permanent magnet. 
     According to this configuration, the first rotating electrical machine rotor can sandwich and hold the permanent magnet between the magnetic pole portions using the magnet holding portion protruding from the inner peripheral surface of the tubular body portion of the outer peripheral iron core portion toward the radial inside. 
     In the first rotating electrical machine rotor, the outer peripheral iron core portion has a structure in which soft magnetic thin plate members are stacked on each other in an axial direction or a structure in which a soft magnetic linear member or a band-shaped member is spirally stacked in the axial direction. The outer peripheral iron core portion is integrated such that the thin plate members or stacked portions of the linear member or the band-shaped member are bonded along the axial direction using the magnet holding portion. 
     According to this configuration, in the first rotating electrical machine rotor, the thin plate members or the stacked portions of the linear member or the band-shaped member are not bonded on an outer peripheral side of the outer peripheral iron core portion. With this configuration, the first rotating electrical machine rotor causes less disturbance in a magnetic flux flow due to a skin effect, and can ensure favorable magnetic properties. Moreover, the magnet holding portion as a thick portion of the outer peripheral iron core portion is present at a portion on which stress due to centrifugal force in association with rotation of a rotating electrical machine is concentrated. In this manner, the strength of the rotor is reinforced. 
     In the first rotating electrical machine rotor, the tubular body portion and the magnet holding portion are formed from different components. 
     According to this configuration, the first rotating electrical machine rotor can reduce waste material upon formation of the outer peripheral iron core portion, and can improve the yield rate when producing the outer peripheral iron core portion. Moreover, a material of the magnet holding portion and a material of the tubular body portion can be changed as necessary. 
     In the first rotating electrical machine rotor, the magnet holding portion has a side surface holding portion facing a corresponding surface of the permanent magnet and extending along the axial direction. According to this configuration, the first rotating electrical machine rotor can hold the permanent magnet in the circumferential direction using the side surface holding portion. 
     In the first rotating electrical machine rotor, the magnetic pole portions include first and second magnetic pole portions formed such that a circumferential width changes from a base side in the axial direction to a tip end side in the axial direction, alternately arranged in the circumferential direction such that the position of the base side in the axial direction and the position of the tip end side in the axial direction are on opposite sides in the axial direction, and magnetized to different polarities. The clearance spaces include first and second clearance spaces inclined from a first side to a second side in the axial direction at a predetermined angle with respect to a rotation axis and provided in different skew directions inclined with respect to the rotation axis. The outer peripheral iron core portion has a structure in which cylindrical first and second divided iron core portions divided in half in the axial direction are bonded at a center position in the axial direction. The first divided iron core portion has the side surface holding portion for holding a first permanent magnet arranged in the first clearance space. The second divided iron core portion has the side surface holding portion for holding a second permanent magnet arranged in the second clearance space. 
     According to this configuration, the first rotating electrical machine rotor holds each of the permanent magnets arranged in the first and second clearance spaces different from each other in the skew direction inclined with respect to the rotation axis by the side surface holding portions of the divided iron core portions as separated bodies divided in half in the axial direction. 
     In the first rotating electrical machine rotor, the first divided iron core portion is formed such that the side surface holding portion holds the permanent magnet in a state in which the first divided iron core portion is inserted onto each magnetic pole portion while rotating in a first spiral direction corresponding to the skew direction of the first clearance space. The second divided iron core portion is formed such that the side surface holding portion holds the permanent magnet in a state in which the second divided iron core portion is inserted onto each magnetic pole portion while rotating in a second spiral direction corresponding to the skew direction of the second clearance space. 
     According to this configuration, in the first rotating electrical machine rotor, each of the first and second divided iron core portions divided in half in the axial direction can be inserted onto the magnetic pole portions while rotating in the spiral direction corresponding to the skew direction of the clearance space, and both of the divided iron core portions can be bonded at the center position in the axial direction. Moreover, the first rotating electrical machine rotor can implement the anti-rotation function of preventing the magnetic pole portions from rotating in the circumferential direction relative to the outer peripheral iron core portion including the first divided iron core portion and the second divided iron core portion after bonding of both of the divided iron core portions. 
     In the first rotating electrical machine rotor, the magnet holding portion has an axial end surface holding portion facing an axial end surface of the permanent magnet and extending along the circumferential direction. According to this configuration, the first rotating electrical machine rotor can hold the permanent magnet in the axial direction using the axial end surface holding portion. 
     In the first rotating electrical machine rotor, the magnet holding portion is formed with a tapered section to divide a space between the permanent magnet and the tubular body portion into an internal space where the permanent magnet is held and a predetermined space formed on the outside of the internal space in the radial direction. Each magnetic pole portion has a tapered portion arranged to fill the predetermined space. 
     According to this configuration, in the first rotating electrical machine rotor, stress on the permanent magnet due to centrifugal force generated in association with rotation of the rotating electrical machine is provided not only to the outer peripheral iron core portion but also to the tapered portion of each magnetic pole portion. Thus, the stress on the permanent magnet due to the centrifugal force is dispersed to the outer peripheral iron core portion and the magnetic pole portions. In this manner, the strength of the rotor is improved. Alternatively, the width of the tubular body portion of the outer peripheral iron core portion in the radial direction can be decreased within a range where predetermined strength is ensured. 
     In the first rotating electrical machine rotor, the permanent magnet is divided into two or more magnets in the circumferential direction at a q-axis at a position shifted from a d-axis passing through the center of each magnetic pole portion in the circumferential direction by an electrical angle of 90°. The magnet holding portion is formed to hold the permanent magnet, surround each magnetic pole portion, and have an iron core portion at which a q-axis magnetic circuit passing through the q-axis is formed. 
     According to this configuration, the first rotating electrical machine rotor can hold, between the magnetic pole portions, the permanent magnets divided in the circumferential direction. Moreover, a q-axis magnetic circuit magnetically isolated from a d-axis magnetic circuit can be formed on the q-axis by means of the magnet holding portion. Thus, reluctance torque is generated to improve torque. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional view of a rotating electrical machine including a rotating electrical machine rotor according to a first embodiment. 
         FIG. 2  is a view when the rotating electrical machine rotor of the first embodiment is viewed from the outside in a radial direction. 
         FIG. 3  is a perspective view of the rotating electrical machine rotor of the first embodiment. 
         FIG. 4  is a perspective view of the rotating electrical machine rotor of the first embodiment excluding an outer peripheral iron core portion. 
         FIG. 5  is a perspective view of part of the rotating electrical machine rotor of the first embodiment. 
         FIG. 6  is a perspective view of part of claw-shaped magnetic pole portions of the outer peripheral iron core portion included in the rotating electrical machine rotor of the first embodiment. 
         FIG. 7  is a perspective view of part of permanent magnets of one divided iron core portion of the outer peripheral iron core portion included in the rotating electrical machine rotor of the first embodiment. 
         FIG. 8  is a sectional view of a main portion of the rotating electrical machine rotor of the first embodiment. 
         FIG. 9  is a plan view of part of thin plate members forming the outer peripheral iron core portion included in the rotating electrical machine rotor of the first embodiment. 
         FIG. 10  is a perspective view of a linear member forming an outer peripheral iron core portion included in a rotating electrical machine rotor according to a variation. 
         FIG. 11  is a perspective view of a band-shaped member forming an outer peripheral iron core portion included in a rotating electrical machine rotor according to a variation. 
         FIG. 12  is a perspective view of a main portion of an outer peripheral iron core portion included in a rotating electrical machine rotor according to a variation. 
         FIG. 13  is a sectional view of a main portion of the rotating electrical machine rotor illustrated in  FIG. 12 . 
         FIG. 14  is a view for describing a phenomenon caused in a case where a magnetic holding portion and a tubular body portion included in an outer peripheral iron core portion of a rotating electrical machine rotor are formed from a single component. 
         FIG. 15  is a sectional view of a main portion of a rotating electrical machine rotor according to a variation. 
         FIG. 16  is a perspective view of part of a rotating electrical machine rotor of a variation. 
         FIG. 17  is a perspective view of the rotating electrical machine rotor illustrated in  FIG. 16  with no claw-shaped magnetic pole portions being illustrated. 
         FIG. 18  is a sectional view of a main portion of a rotating electrical machine rotor according to a variation. 
         FIG. 19  is a sectional view of a main portion of a rotating electrical machine rotor according to a variation. 
         FIG. 20  is a sectional view of a main portion of a rotating electrical machine rotor according to a variation. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, a specific embodiment of a rotating electrical machine rotor as one aspect of the technique of the present disclosure will be described with reference to the drawings. First, a configuration of a rotating electrical machine including a rotor according to a first embodiment will be described with reference to  FIGS. 1 to 9 . 
     First Embodiment 
     In the present embodiment, a rotating electrical machine rotor  20  is, as illustrated in  FIG. 1  by way of example, a rotor provided at a rotating electrical machine  22  mounted on, e.g., a vehicle. Hereinafter, the rotating electrical machine rotor  20  will be simply referred to as a “rotor  20 .” The rotating electrical machine  22  is configured to receive power supplied from a power source such as a battery, thereby generating drive force for driving the vehicle. Moreover, the rotating electrical machine  22  is configured to receive drive force supplied from an engine of the vehicle, thereby generating power for charging the battery. The rotating electrical machine  22  includes the rotor  20 , a stator  24 , a housing  26 , a brush device  28 , a rectification device  30 , a voltage adjuster  32 , and a pulley  34 . 
     As illustrated in  FIGS. 1, 2, 3, and 4  by way of example, the rotor  20  includes a boss portion  40 , a disc portion  42 , claw-shaped magnetic pole portions  44 , an outer peripheral iron core portion  46 , a field winding  48 , and permanent magnets  49 . The rotor  20  is a Lundell type rotor. The boss portion  40  is a tubular member having a shaft hole  52  opening on a center axis so that a rotary shaft  50  can be inserted into the shaft hole  52 . The boss portion  40  is a portion to be fitted and fixed on an outer peripheral side of the rotary shaft  50 . The disc portion  42  is a discoid portion extending from an end surface side of the boss portion  40  in an axial direction toward the outside in a radial direction. 
     The claw-shaped magnetic pole portions  44  are continuously connected to an outer peripheral end of the disc portion  42 . The claw-shaped magnetic pole portion  44  is a member protruding in a claw shape from such a connection portion along the axial direction. The claw-shaped magnetic pole portions  44  are arranged on the outside of the boss portion  40  in the radial direction. The boss portion  40 , the disc portion  42 , and the claw-shaped magnetic pole portions  44  form a pole core (a field core). The pole core is, e.g., molded by hammering. The claw-shaped magnetic pole portion  44  has an outer peripheral surface formed in an arc shape. The outer peripheral surface of the claw-shaped magnetic pole portion  44  has an arc about the vicinity of the axial center of the rotary shaft  50 . Specifically, the outer peripheral surface of the claw-shaped magnetic pole portion  44  has an arc about the axial center of the rotary shaft  50  or an arc about a position closer to the claw-shaped magnetic pole portion  44  with respect to the axial center. 
     The claw-shaped magnetic pole portions  44  include first claw-shaped magnetic pole portions  44 - 1  and second claw-shaped magnetic pole portions  44 - 2 , the first claw-shaped magnetic pole portion  44 - 1  and the second claw-shaped magnetic pole portion  44 - 2  being magnetized to different polarities (the N-pole and the S-pole). The first claw-shaped magnetic pole portion  44 - 1  and the second claw-shaped magnetic pole portion  44 - 2  form a pair of pole cores. The same number (e.g., eight) of first claw-shaped magnetic pole portions  44 - 1  and the same number of second claw-shaped magnetic pole portions  44 - 2  are provided about the axis of the rotary shaft  50 . The first claw-shaped magnetic pole portions  44 - 1  and the second claw-shaped magnetic pole portions  44 - 2  are alternately arranged with clearance spaces  54  in a circumferential direction. 
     The first claw-shaped magnetic pole portions  44 - 1  are continuously connected to the outer peripheral end of the disc portion  42  extending from a first end side of the boss portion  40  in the axial direction to the radial outside. Moreover, the first claw-shaped magnetic pole portions  44 - 1  protrude toward a second end side in the axial direction. The second claw-shaped magnetic pole portions  44 - 2  are continuously connected to the outer peripheral end of the disc portion  42  extending from the second end side of the boss portion  40  in the axial direction to the radial outside. Moreover, the second claw-shaped magnetic pole portions  44 - 2  protrude toward the first end side in the axial direction. The first claw-shaped magnetic pole portion  44 - 1  and the second claw-shaped magnetic pole portion  44 - 2  are formed in a common shape, except for an arrangement position and a protruding direction in the axial direction. The first claw-shaped magnetic pole portions  44 - 1  and the second claw-shaped magnetic pole portions  44 - 2  are alternately arranged in the circumferential direction such that a base side in the axial direction and a tip end side in the axial direction are on opposite sides in the axial direction. Moreover, the first claw-shaped magnetic pole portion  44 - 1  and the second claw-shaped magnetic pole portion  44 - 2  are magnetized to different polarities. 
     Each of the claw-shaped magnetic pole portions  44  including the first claw-shaped magnetic pole portions  44 - 1  and the second claw-shaped magnetic pole portions  44 - 2  is formed with a predetermined width (a circumferential width) in the circumferential direction and a predetermined thickness (a radial thickness) in the radial direction. Each claw-shaped magnetic pole portion  44  is formed such that the circumferential width gradually decreases and the radial thickness gradually decreases from the base side near the portion continuously connected to the disc portion  42  toward the tip end side in the axial direction. That is, each claw-shaped magnetic pole portion  44  is, in both of the circumferential direction and the radial direction, formed narrower toward the tip end side in the axial direction. Each claw-shaped magnetic pole portion  44  is preferably formed symmetrically in the circumferential direction with respect to the center in the circumferential direction. 
     Each of the above-described clearance spaces  54  is provided between the first claw-shaped magnetic pole portion  44 - 1  and the second claw-shaped magnetic pole portion  44 - 2  adjacent to each other in the circumferential direction. The clearance space  54  extends diagonally in the axial direction. Moreover, the clearance space  54  is inclined from a first side to a second side in the axial direction at a predetermined angle with respect to a rotation axis of the rotor  20 . All clearance spaces  54  have the same shape. Each clearance space  54  is set such that a size (a dimension) in the circumferential direction little changes according to a position in the axial direction. That is, it is set such that the dimension of each clearance space  54  in the circumferential direction is maintained constant or is maintained within a slight range including such a constant value. That is, the first claw-shaped magnetic pole portions  44 - 1  and the second claw-shaped magnetic pole portions  44 - 2  are arranged such that the clearance spaces  54  have a constant circumferential dimension at any position in the axial direction and all clearance spaces  54  in the circumferential direction have the same shape. 
     In the rotor  20 , all clearance spaces  54  in the circumferential direction preferably have the same shape for avoiding magnetic unbalance. However, particularly in the rotor  20  configured to rotate only in one direction, the shape of the claw-shaped magnetic pole portion  44  may be, for, e.g., reduction in iron loss, a shape asymmetrical in the circumferential direction with respect to the center in the circumferential direction, and the dimension of the clearance space  54  in the circumferential direction is not necessarily constant according to the position in the axial direction. 
     The outer peripheral iron core portion  46  is arranged on an outer peripheral side of the claw-shaped magnetic pole portions  44  (the first claw-shaped magnetic pole portions  44 - 1  and the second claw-shaped magnetic pole portions  44 - 2 ). The outer peripheral iron core portion  46  is a cylindrical or circular ring-shaped member covering the outer periphery of the claw-shaped magnetic pole portions  44 . The outer peripheral iron core portion  46  is a thin plate member having a predetermined thickness (e.g., about 0.6 [mm] to 1.0 [mm] realizing both of the mechanical strength and magnetic performance of the rotor  20 ) in the radial direction. The outer peripheral iron core portion  46  contacts the claw-shaped magnetic pole portions  44  with the outer peripheral iron core portion  46  facing the outer peripheral side of the claw-shaped magnetic pole portions  44 . Moreover, the outer peripheral iron core portion  46  closes the clearance spaces  54  on the outside of the clearance spaces  54  in the radial direction, and couples the claw-shaped magnetic pole portions  44  adjacent to each other in the circumferential direction. 
     The outer peripheral iron core portion  46  is made of a soft magnetic material such as a magnetic steel sheet made of, e.g., iron or silicon steel. As illustrated in  FIG. 2  by way of example, the outer peripheral iron core portion  46  has such a structure that multiple soft magnetic thin plate members (e.g., magnetic steel sheets)  56  are stacked on each other in the axial direction. The thin plate member  56  is a punched-out member punched out in a desired shape by means of a die. Each thin plate member  56  has a predetermined thickness in the radial direction, and has a predetermined width in a stacking direction. For reducing eddy-current loss, each thin plate member  56  is interlayer-insulated from adjacent thin plate members  56  in the axial direction. The outer peripheral iron core portion  46  is fixed to the claw-shaped magnetic pole portions  44  by shrink fitting, pressure fitting, welding, or a combination thereof. 
     The outer peripheral iron core portion  46  has the function of smoothing an outer peripheral surface of the rotor  20  to reduce wind noise due to irregularity of the outer peripheral surface of the rotor  20 . Moreover, the outer peripheral iron core portion  46  has the function of coupling the multiple claw-shaped magnetic pole portions  44  arranged in the circumferential direction to reduce deformation (particularly deformation in the radial direction) of each claw-shaped magnetic pole portion  44 . 
     The field winding  48  is arranged in a clearance between the boss portion  40  and each claw-shaped magnetic pole portion  44 . The field winding  48  is a coil member configured to generate a magnetic flux by distribution of DC current. The field winding  48  is wound about the axis on an outer peripheral side of the boss portion  40 . The magnetic flux generated by the field winding  48  is guided to the claw-shaped magnetic pole portions  44  via the boss portion  40  and the disc portion  42 . That is, the boss portion  40  and the disc portion  42  form a magnetic path portion for guiding the magnetic flux generated at the field winding  48  to the claw-shaped magnetic pole portions  44 . The field winding  48  has the function of magnetizing, by the generated magnetic flux, the first claw-shaped magnetic pole portions  44 - 1  to the N-pole and magnetizing the second claw-shaped magnetic pole portions  44 - 2  to the S-pole. 
     The permanent magnets  49  are housed on an inner peripheral side of the outer peripheral iron core portion  46 . The permanent magnet  49  is an inter-pole magnet arranged to fill the clearance space  54  between adjacent ones of the claw-shaped magnetic pole portions  44  in the circumferential direction (between the first claw-shaped magnetic pole portion  44 - 1  and the second claw-shaped magnetic pole portion  44 - 2 ). The permanent magnets  49  are each arranged in the clearance spaces  54 , and the same number of permanent magnets  49  as that of the clearance spaces  54  is provided. Each permanent magnet  49  extends along the shape of the clearance space  54 , inclined diagonally with respect to the rotation axis of the rotor  20 . Moreover, each permanent magnet  49  is formed in a substantially rectangular parallelepiped shape. The permanent magnets  49  are held with a holder described in detail later. The permanent magnet  49  has the function of reducing magnetic flux leakage between the claw-shaped magnetic pole portions  44  of the rotor  20  and enhancing a magnetic flux between the claw-shaped magnetic pole portion  44  and a stator iron core of the stator  24 . 
     The permanent magnet  49  is arranged such that a magnetic pole in the direction of decreasing magnetic flux leakage between the claw-shaped magnetic pole portions  44  adjacent in the circumferential direction is formed. Specifically, the permanent magnet  49  is configured such that its N magnetic pole faces towards the N-pole of the first claw-shaped magnetic pole portion  44 - 1 . Moreover, the permanent magnet  49  is configured such that its S magnetic pole faces towards the S-pole of the first claw-shaped magnetic pole portion  44 - 2 . The permanent magnet  49  is configured as described above. The permanent magnet  49  is magnetized such that magnetomotive force is in the circumferential direction. Note that the present embodiment may be applied to a configuration in which the permanent magnets  49  are mounted in the rotor  20  after having been magnetized. Note that the present embodiment is preferably applied to a configuration in which the permanent magnets  49  are magnetized after having been mounted in the rotor  20 . 
     In description below, the clearance space  54  will be sometimes described as two divided spaces (first and second clearance spaces). Specifically, a clearance when the first claw-shaped magnetic pole portion  44 - 1  is present on a first side in the circumferential direction (on a leftward rotation side as a counterclockwise side in  FIG. 4 ) and the second claw-shaped magnetic pole portion  44 - 2  is present on a second side in the circumferential direction (on a rightward rotation side as a clockwise side in  FIG. 4 ) will be referred to as a “first clearance space  54   a .” Moreover, a clearance when the first claw-shaped magnetic pole portion  44 - 1  is present on the second side in the circumferential direction and the second claw-shaped magnetic pole portion  44 - 2  is present on the first side in the circumferential direction will be referred to as a “second clearance space  54   b.”   
     The first clearance space  54   a  and the second clearance space  54   b  are provided such that a skew direction inclined with respect to the rotation axis of the rotor  20  is different between a counterclockwise spiral direction and a clockwise spiral direction. The first clearance space  54   a  is skewed away from the counterclockwise spiral direction with respect to the rotation axis. Moreover, the second clearance space  54   b  is skewed away from the clockwise spiral direction with respect to the rotation axis. Preferably, an absolute value of the angle of the first clearance space  54   a  with respect to the rotation axis in the skew direction and an absolute value of the angle of the second clearance space  54   b  with respect to the rotation axis in the skew direction are substantially same as each other. Note that the “counterclockwise spiral direction” indicates that a direction from a near side to a far side is counterclockwise. Moreover, the “clockwise spiral direction” indicates that the direction from the near side to the far side is clockwise. 
     In description below, the permanent magnet  49  will be sometimes described as two divided magnets (first and second permanent magnets). Specifically, a magnet arranged in the first clearance space  54   a  such that a side surface  58   n  whose magnetic pole is the N-pole faces a first side in the circumferential direction (on the leftward rotation side as the counterclockwise side in  FIG. 4 ) and a side surface  58   s  whose magnetic pole is the S-pole faces a second side in the circumferential direction (on the rightward side as the clockwise side in  FIG. 4 ) will be referred to as a “first permanent magnet  49   a .” Moreover, a magnet arranged in the second clearance space  54   b  such that a side surface  58   n  whose magnetic pole is the N-pole faces the second side in the circumferential direction and a side surface  58   s  whose magnetic pole is the S-pole faces the first side in the circumferential direction will be referred to as a “second permanent magnet  49   b .” As illustrated in  FIGS. 4, 5, and 7  by way of example, the first permanent magnet  49   a  is arranged to extend in the counterclockwise spiral direction with respect to the rotation axis. Moreover, as illustrated in  FIG. 4  by way of example, the second permanent magnet  49   b  is arranged to extend in the clockwise spiral direction with respect to the rotation axis. 
     The stator  24  has a stator iron core  60  and a stator winding  62 . The stator iron core  60  is a member formed in a cylindrical shape. The stator iron core  60  is arranged facing the rotor  20  with a predetermined air gap on the radial outside. The stator winding  62  is a coil member wound around teeth of the stator iron core  60  such that each straight portion is housed in a slot formed at the stator iron core  60 . The stator winding  62  corresponds to multiple phases (e.g., three phases). 
     The stator  24  forms part of a magnetic path. The stator  24  is a member configured to receive a rotating magnetic field provided by rotation of the rotor  20 , thereby generating electromotive force. The rotor  20  forms part of the magnetic path. The rotor  20  is a member configured to form a magnetic pole by a current flow. 
     The housing  26  is a case member configured to house the stator  24  and the rotor  20 . The housing  26  supports the rotor  20  such that the rotor  20  is rotatable about the axis of the rotary shaft  50 . Moreover, the housing  26  fixes the stator  24 . 
     The brush device  28  has a slip ring  64  and brushes  66 . The slip ring  64  is fixed to a first end of the rotary shaft  50  in the axial direction. The slip ring  64  has the function of supplying current to the field winding  48  of the rotor  20 . Two brushes  66  are provided in a pair. Moreover, the brushes  66  are held by a brush holder attached to the housing  26  in a fixed manner. The brushes  66  are arranged while being pressed toward the rotary shaft  50  such that inner tip ends of the brushes  66  in the radial direction slide on a surface of the slip ring  64 . The brushes  66  are configured to apply current to the field winding  48  via the slip ring  64 . 
     The rectification device  30  is electrically connected to the stator winding  62  of the stator  24 . The rectification device  30  is a device configured to rectify AC generated by the stator winding  62  into DC, thereby outputting the DC. The voltage adjuster  32  is configured to control field current flowing in the field winding  48 , thereby adjusting the output voltage of the rotating electrical machine  22 . The voltage adjuster  32  has the function of maintaining the output voltage substantially constant, the output voltage being changeable according to an electric load or a power generation amount. The pulley  34  is configured to transmit rotation of the vehicle engine to the rotor  20  of the rotating electrical machine  22 . The pulley  34  is fastened and fixed to a second end of the rotary shaft  50  in the axial direction. 
     In the rotating electrical machine  22  having such a structure, DC current is supplied from the power source to the field winding  48  of the rotor  20  via the brush device  28 . Then, in the rotating electrical machine  22 , such current generates a magnetic flux circulating in the boss portion  40 , the disc portion  42 , and the claw-shaped magnetic pole portions  44  through the field winding  48 . This magnetic flux forms, for example, a magnetic circuit for a flow in the order of the boss portion  40  of one pole core, the disc portion  42 , the first claw-shaped magnetic pole portions  44 - 1 , the stator iron core  60 , the second claw-shaped magnetic pole portions  44 - 2 , the disc portion  42  of the other pole core, the boss portion  40 , and the boss portion  40  of one pole core. This magnetic circuit generates back electromotive force of the rotor  20 . 
     The above-described magnetic flux is guided to the first claw-shaped magnetic pole portions  44 - 1  and the second claw-shaped magnetic pole portions  44 - 2 . As a result, the first claw-shaped magnetic pole portions  44 - 1  are magnetized to the N-pole. Moreover, the second claw-shaped magnetic pole portions  44 - 2  are magnetized to the S-pole. In a state in which such magnetization of the claw-shaped magnetic pole portions  44  is performed, DC current supplied from the power source is converted into, e.g., three-phase AC, and then, the three-phase AC is supplied to the stator winding  62 . In this manner, the rotor  20  rotates relative to the stator  24 . Thus, in the configuration according to the present embodiment, the rotating electrical machine  22  can function as an electric motor to be rotatably driven by a power supply to the stator winding  62 . 
     The rotor  20  of the rotating electrical machine  22  is rotated in such a manner that rotation torque of the vehicle engine is transmitted to the rotary shaft  50  via the pulley  34 . Rotation of the rotor  20  provides the rotating magnetic field to the stator winding  62  of the stator  24 , thereby generating AC electromotive force at the stator winding  62 . The AC electromotive force generated at the stator winding  62  is rectified into DC through the rectification device  30 , and thereafter, the DC is supplied to the battery. Thus, in the configuration according to the present embodiment, the rotating electrical machine  22  can function as a power generator configured to charge the battery by generation of the electromotive force of the stator winding  62 . 
     Next, characteristic portions of the rotor  20  of the present embodiment will be described with reference to  FIGS. 5 to 9 . 
     In the present embodiment, the rotor  20  includes the tubular outer peripheral iron core portion  46  covering the radial outside, i.e., the outer peripheral side of the claw-shaped magnetic pole portions  44 . The permanent magnet  49  is arranged between adjacent ones of the claw-shaped magnetic pole portions  44  (in the clearance space  54 ). Moreover, the permanent magnets  49  are each held by magnet holding portions  70 . As illustrated in  FIG. 6  by way of example, the magnet holding portions  70  are provided integrally with the outer peripheral iron core portion  46 . The magnet holding portions  70  are made of the same soft magnetic material as that of a tubular body portion  72  of the outer peripheral iron core portion  46 . That is, the outer peripheral iron core portion  46  has the magnet holding portions  70  as the holder for holding the permanent magnets  49 . 
     The magnet holding portion  70  is a portion molded integrally with the tubular body portion  72  of the outer peripheral iron core portion  46 . The magnet holding portion  70  is provided integrally with an inner peripheral surface of the tubular body portion  72 . The magnet holding portion  70  is a raised portion formed to hold the permanent magnet  49  while protruding from the inner peripheral surface of the tubular body portion  72  toward the radial inside (toward the axial center). The magnet holding portions  70  are, in a one-on-one manner, provided corresponding to all permanent magnets  49  included in the rotor  20 . The magnet holding portions  70  include first magnet holding portions  70   a  each configured to hold the first permanent magnets  49   a , and second magnet holding portions  70   b  each configured to hold the second permanent magnets  49   b.    
     The magnet holding portion  70  is arranged on four sides (both sides in the circumferential direction and both sides in the axial direction) of the substantially rectangular parallelepiped permanent magnet  49  inserted into the clearance space  54 . The magnet holding portion  70  has, for each permanent magnet  49 , a pair of side surface holding portions  74  forming walls facing the circumferential direction, and a pair of axial end surface holding portions  76  forming walls facing the axial direction. The first magnet holding portions  70   a  are each provided corresponding to the first permanent magnets  49   a . Specifically, as illustrated in  FIG. 6  by way of example, the first magnet holding portion  70   a  has a pair of side surface holding portions  74   a - 1 ,  74   a - 2  and a pair of axial end surface holding portions  76   a - 1 ,  76   a - 2 . Moreover, the second magnet holding portions  70   b  are each provided corresponding to the second permanent magnets  49   b . Specifically, as illustrated in  FIG. 6  by way of example, the second magnet holding portion  70   b  has a pair of side surface holding portions  74   b - 1 ,  74   b - 2  and a pair of axial end surface holding portions  76   b - 1 ,  76   b - 2 . 
     As illustrated in  FIGS. 7 and 8  by way of example, the side surface holding portion  74   a - 1  extends inclined (inclined to the counterclockwise spiral direction in  FIG. 6 ) along the shapes of the first clearance space  54   a  and the first permanent magnet  49   a  on the inner peripheral surface of the tubular body portion  72 . The side surface holding portion  74   a - 1  is a holding portion facing the side surface portion  58   n  of the first permanent magnet  49   a , the first permanent magnet  49   a  facing the first claw-shaped magnetic pole portion  44 - 1  in the circumferential direction, the side surface portion  58   n  being N-poles. The side surface holding portion  74   a - 2  extends inclined (inclined to the counterclockwise spiral direction in  FIG. 6 ) along the shapes of the first clearance space  54   a  and the first permanent magnet  49   a  on the inner peripheral surface of the tubular body portion  72 . The side surface holding portion  74   a - 2  is a holding portion facing the side surface portion  58   s  of the first permanent magnet  49   a , the first permanent magnet  49   a  facing the second claw-shaped magnetic pole portion  44 - 2  in the circumferential direction, the side surface portion  58   s  being S-poles. 
     The pair of side surface holding portions  74   a - 1 ,  74   a - 2  holding the first permanent magnet  49   a  extends along the same counterclockwise spiral direction in accordance with the shapes of the first permanent magnet  49   a  and the first clearance space  54   a . Such an extension direction is the same as a direction in which the first clearance space  54   a  and the first permanent magnet  49   a  extend. The side surface holding portion  74   a - 1  and the side surface holding portion  74   a - 2  are apart from each other in the circumferential direction by a distance corresponding to the circumferential width of the first permanent magnet  49   a . The pair of side surface holding portions  74   a - 1 ,  74   a - 2  has the function of holding the first permanent magnet  49   a  with the first permanent magnet  49   a  being griped at the side surface  58   n  and the side surface  58   s  thereof in the circumferential direction. 
     Similarly, the side surface holding portion  74   b - 1  extends inclined (inclined to the clockwise spiral direction in  FIG. 6 ) along the shapes of the second clearance space  54   b  and the second permanent magnet  49   b  on the inner peripheral surface of the tubular body portion  72 . The side surface holding portion  74   b - 1  is a holding portion facing the side surface portion  58   n  of the second permanent magnet  49   b , the second permanent magnet  49   b  facing the first claw-shaped magnetic pole portion  44 - 1  in the circumferential direction, the side surface portion  58   n  being N-poles. The side surface holding portion  74   b - 2  extends inclined (inclined to the clockwise spiral direction in  FIG. 6 ) along the shapes of the second clearance space  54   b  and the second permanent magnet  49   b  on the inner peripheral surface of the tubular body portion  72 . The side surface holding portion  74   b - 2  is a holding portion facing the side surface portion  58   s  of the second permanent magnet  49   b , the second permanent magnet  49   b  facing the second claw-shaped magnetic pole portion  44 - 2  in the circumferential direction, the side surface portion  58   s  being N-poles. 
     The pair of side surface holding portions  74   b - 1 ,  74   b - 2  holding the second permanent magnet  49   b  extends along the same clockwise spiral direction in accordance with the shapes of the second permanent magnet  49   b  and the second clearance space  54   b . Such an extension direction is the same as a direction in which the second clearance space  54   b  and the second permanent magnet  49   b  extend. The side surface holding portion  74   b - 1  and the side surface holding portion  74   b - 2  are apart from each other in the circumferential direction by a distance corresponding to the circumferential width of the second permanent magnet  49   b . The pair of side surface holding portions  74   b - 1 ,  74   b - 2  has the function of holding the second permanent magnet  49   b  with the second permanent magnet  49   b  being griped at the side surface  58   n  and the side surface  58   s  thereof in the circumferential direction. 
     The side surface holding portions  74   a - 1 ,  74   a - 2  are formed between the first end (a lower end in  FIG. 6 ) of the tubular body portion  72  of the outer peripheral iron core portion  46  in the axial direction and a center position in the axial direction. Moreover, the side surface holding portions  74   b - 1 ,  74   b - 2  are formed between the second end (an upper end in  FIG. 6 ) of the tubular body portion  72  of the outer peripheral iron core portion  46  in the axial direction and the center position in the axial direction. An axial area where the side surface holding portions  74   a - 1 ,  74   a - 2  are positioned in the axial direction and an axial area where the side surface holding portions  74   b - 1 ,  74   b - 2  are positioned in the axial direction do not overlap with each other. Each of the side surface holding portions  74   a - 1 ,  74   a - 2 ,  74   b - 1 ,  74   b - 2  has an axial length corresponding to about ½ of the length of the tubular body portion  72  in the axial direction. 
     The axial end surface holding portion  76   a - 1  extends along the circumferential direction. The axial end surface holding portion  76   a - 1  is a holding portion of the first permanent magnet  49   a  facing an axial end surface  78   e  on the tip end side of the first claw-shaped magnetic pole portion  44 - 1  and the base side of the second claw-shaped magnetic pole portion  44 - 2 . The axial end surface holding portion  76   a - 2  extends along the circumferential direction. The axial end surface holding portion  76   a - 2  is a holding portion of the first permanent magnet  49   a  facing an axial end surface  78   w  on the base side of the first claw-shaped magnetic pole portion  44 - 1  and the tip end side of the second claw-shaped magnetic pole portion  44 - 2 . 
     The axial end surface holding portion  76   a - 1  and the axial end surface holding portion  76   a - 2  are apart from each other in the axial direction by a distance corresponding to the width of the first permanent magnet  49   a  in the axial direction. The axial end surface holding portion  76   a - 1  and the axial end surface holding portion  76   a - 2  are arranged shifted from each other in the circumferential direction by an amount corresponding to diagonal extension of the first permanent magnet  49   a  in the axial direction. The axial end surface holding portion  76   a - 1  and the axial end surface holding portion  76   a - 2  have the function of holding the first permanent magnet  49   a  with the first permanent magnet  49   a  being griped at the axial end surface  78   w  and the axial end surface  78   e  thereof in the axial direction. 
     Similarly, the axial end surface holding portion  76   b - 1  extends along the circumferential direction. The axial end surface holding portion  76   b - 1  is a holding portion of the second permanent magnet  49   b  facing the axial end surface  78   e  on the tip end side of the first claw-shaped magnetic pole portion  44 - 1  and the base side of the second claw-shaped magnetic pole portion  44 - 2 . The axial end surface holding portion  76   b - 2  extends along the circumferential direction. The axial end surface holding portion  76   b - 2  is a holding portion of the second permanent magnet  49   b  facing the axial end surface  78   w  on the base side of the first claw-shaped magnetic pole portion  44 - 1  and the tip end side of the second claw-shaped magnetic pole portion  44 - 2 . 
     The axial end surface holding portion  76   b - 1  and the axial end surface holding portion  76   b - 2  are apart from each other in the axial direction by a distance corresponding to the width of the second permanent magnet  49   b  in the axial direction. The axial end surface holding portion  76   b - 1  and the axial end surface holding portion  76   b - 2  are arranged shifted from each other in the circumferential direction by an amount corresponding to diagonal extension of the second permanent magnet  49   b  in the axial direction. The axial end surface holding portion  76   b - 1  and the axial end surface holding portion  76   b - 2  have the function of holding the second permanent magnet  49   b  with the second permanent magnet  49   b  being griped at the axial end surface  78   w  and the axial end surface  78   e  thereof in the axial direction. 
     The outer peripheral iron core portion  46  has such a structure that the multiple thin plate members  56  are stacked on each other in the axial direction as described above. The thin plate members  56  form the tubular body portion  72  and the side surface holding portions  74  of the outer peripheral iron core portion  46 . That is, the tubular body portion  72  and the side surface holding portions  74  are formed in such a manner that the thin plate members  56  are stacked on each other in the axial direction. As illustrated in  FIG. 9  by way of example, each thin plate member  56  has a circular ring portion  56   a  corresponding to the tubular body portion  72 , and raised portions  56   b  corresponding to the side surface holding portions  74 . Note that only some, or none of, the thin plate members  56  do not necessarily have the raised portions  56   b . The thin plate members  56  arranged in the vicinity of both ends of the outer peripheral iron core portion  46  in the axial direction do not necessarily have the raised portions  56   b . The circular ring portion  56   a  is formed in a circular ring shape. The raised portions  56   b  are formed to extend from an inner peripheral surface of the circular ring portion  56   a  toward the axial center. 
     In a case where the side surface holding portions  74  extending diagonally in the axial direction are formed using the multiple thin plate members  56 , the shape may be slightly changed for each thin plate member  56 , and these thin plate members  56  having different shapes may be stacked on each other in the axial direction. Alternatively, the positions of the thin plate members  56  having the same shape may be slightly shifted from each other in the circumferential direction, and these thin plate members  56  may be stacked on each other in the axial direction. 
     In the outer peripheral iron core portion  46 , the raised portions  56   b  of the thin plate members  56  forming the side surface holding portions  74  are joined and bonded to each other along the axial direction by, e.g., welding or adhesive bonding in a state in which the multiple thin plate members  56  having the circular ring portions  56   a  and the raised portions  56   b  are stacked on each other in the axial direction. In this manner, the outer peripheral iron core portion  46  is integrated. Such joining or bonding is implemented by, e.g., welding to an inner peripheral surface of the outer peripheral iron core portion  46  provided with the side surface holding portions  74 . 
     The axial end surface holding portions  76  are formed using some (e.g., one to three thin plate members  56 ) of all thin plate members  56  forming the outer peripheral iron core portion  46 . These thin plate members  56  forming the axial end surface holding portions  76  are punched out in a shape different from that of the other thin plate members  56  (the thin plate members  56  not forming the axial end surface holding portions  76 ). Specifically, as illustrated in  FIG. 9  by way of example, the thin plate members  56  have raised portions  56   c  corresponding to the axial end surface holding portions  76 . 
     The axial end surface holding portion  76   a - 1  corresponding to the first permanent magnet  49   a  and the axial end surface holding portion  76   b - 1  corresponding to the second permanent magnet  49   b  are arranged apart from each other in the circumferential direction at the same axial position. In this configuration, the axial end surface holding portion  76   a - 1  and the axial end surface holding portion  76   b - 1  may be formed using the same type of thin plate member  56 . Moreover, the axial end surface holding portion  76   a - 2  corresponding to the first permanent magnet  49   a  and the axial end surface holding portion  76   b - 2  corresponding to the second permanent magnet  49   b  are arranged apart from each other in the circumferential direction at the same axial position. In this configuration, the axial end surface holding portion  76   a - 2  and the axial end surface holding portion  76   b - 2  may be formed using the same type of thin plate member  56 . 
     The axial end surface holding portions  76  may be, as described above, formed using the thin plate members  56  punched out to have the raised portions  56   c  in advance. Alternatively, the axial end surface holding portions  76  may be, for example, formed in such a manner that after the outer peripheral iron core portion  46  has been temporarily formed using the thin plate members  56  having no raised portions  56   c , portions to be formed as the axial end surface holding portions  76  in the formed outer peripheral iron core portion  46  are pressed from an outer peripheral side by a pressing device. 
     Each of the side surface holding portions  74  and the axial end surface holding portions  76  of the outer peripheral iron core portion  46  may have such a radial height that the side surface holding portions  74  and the axial end surface holding portions  76  can hold the permanent magnets  49 . Each of the raised portions  56   b ,  56   c  of the thin plate members  56  may be formed to have such a radial length that the raised portions  56   b ,  56   c  can hold the permanent magnets  49 . For example, the radial height or the radial length is set to a value corresponding to about ½ of the axial width of the side surface  58   n ,  58   s  or the axial end surface  78   w ,  78   e  of the permanent magnet  49 . 
     As illustrated in  FIG. 6  by way of example, the outer peripheral iron core portion  46  is formed in such a manner that cylindrical divided iron core portions  46 - 1 ,  46 - 2  divided in half in the axial direction are bonded at the center position of the outer peripheral iron core portion  46  in the axial direction. Such bonding of the divided iron core portions  46 - 1 ,  46 - 2  may be performed using an adhesive, for example. Alternatively, such bonding may be performed by welding. The first divided iron core portion  46 - 1  has the pairs of side surface holding portions  74   a - 1 ,  74   a - 2  and the axial end surface holding portions  76   a - 1  of the first magnet holding portions  70   a  and the axial end surface holding portions  76   b - 1  of the second magnet holding portions  70   b . Moreover, the second divided iron core portion  46 - 2  has the axial end surface holding portions  76   a - 2  of the first magnet holding portions  70   a  and the pairs of side surface holding portions  74   b - 1 ,  74   b - 2  and the axial end surface holding portions  76   b - 2  of the second magnet holding portions  70   b.    
     As described above, in the structure of the rotor  20  of the present embodiment, the permanent magnet  49  arranged between adjacent ones of the claw-shaped magnetic pole portions  44  is held by the magnet holding portion  70  provided integrally with the outer peripheral iron core portion  46 . Specifically, the side surfaces  58   n ,  58   s  of the permanent magnet  49  are, in contact with the pair of side surface holding portions  74   a - 1 ,  74   a - 2  of the outer peripheral iron core portion  46 , sandwiched between the side surface holding portions  74   a - 1 ,  74   a - 2  in the circumferential direction. In addition, the axial end surfaces  78   w ,  78   e  of the permanent magnet  49  are in contact with the pair of axial end surface holding portions  76   a - 1 ,  76   a - 2  of the outer peripheral iron core portion  46 , sandwiched between the axial end surface holding portions  76   a - 1 ,  76   a - 2  in the axial direction. In this manner, the permanent magnets  49  are held. 
     The above-described magnet holding portions  70  are made of a soft magnetic material as in the tubular body portion  72  of the outer peripheral iron core portion  46 . In this case, the magnet holding portion  70  holding the permanent magnet  49  is arranged as the iron core. Specifically, the magnet holding portion  70  is arranged along the side surfaces  58   n ,  58   s  and the axial end surfaces  78   w ,  78   e  of the permanent magnet  49 . In this configuration of the rotor  20 , the magnet holding portion  70  holding the permanent magnet  49  is not formed from a non-magnetic body such as austenite or SUS in the present embodiment. Thus, in the rotor  20  of the present embodiment, magnetic resistance of the magnetic circuit formed for each permanent magnet  49  can be reduced. That is, in the rotor  20  of the present embodiment, the magnetic resistance of the magnetic circuit for a flow in the order of the permanent magnets  49 , the first claw-shaped magnetic pole portions  44 - 1 , the stator iron core  60 , the second claw-shaped magnetic pole portions  44 - 2 , and the permanent magnets  49  can be reduced. 
     The magnet holding portion  70  has the pair of side surface holding portions  74   a - 1 ,  74   a - 2  and the pair of axial end surface holding portions  76   a - 1 ,  76   a - 2 . Moreover, the magnet holding portion  70  holds the permanent magnet  49  at the surfaces in close contact with the permanent magnet  49 . The pair of side surface holding portions  74   a - 1 ,  74   a - 2  and the pair of the axial end surface holding portions  76   a - 1 ,  76   a - 2  are arranged on four sides of the substantially rectangular parallelepiped permanent magnet  49 . In this configuration of the rotor  20 , no large gap is formed between the permanent magnet  49  and the claw-shaped magnetic pole portion  44  in the present embodiment. Thus, in the rotor  20  of the present embodiment, the magnetic resistance of the magnetic circuit passing through the permanent magnets  49  as described above can be reduced. 
     The magnet holding portion  70  is formed in such a manner that the thin plate members  56  punched out in a desired shape are stacked on each other in the axial direction. Thus, in the rotor  20  of the present embodiment, the magnet holding portion  70  is not made of a material subjected to bending or rolling. Consequently, in the rotor  20  of the present embodiment, degradation of magnetic properties can be prevented, and magnetic force can be improved. 
     Thus, in the rotor  20  of the present embodiment, the permanent magnet  49  can be held between adjacent ones of the claw-shaped magnetic pole portions  44  by the magnet holding portion  70 . Moreover, in the rotor  20  of the present embodiment, such a magnet holding portion  70  is formed from a magnetic body such that permeance of the magnetic circuit passing through the permanent magnets  49  is increased. 
     If bonding such a welding is performed on an outer peripheral side of the outer peripheral iron core portion  46 , the thin plate members  56  are bonded to each other at a thin portion of the outer peripheral iron core portion  46 . In this case, disturbance in the magnetic flux flow due to a skin effect is easily caused on an outer peripheral side of the rotor  20  facing an inner peripheral surface of the stator  24 . For this reason, the magnetic properties are degraded. Moreover, strength at a welded position is generally lowered. Thus, there is a probability that strength on a tubular body portion  72  side of the outer peripheral iron core portion  46  to which stress on the claw-shaped magnetic pole portions  44  or the permanent magnets  49  due to centrifugal force in association with rotation of the rotating electrical machine  22  is provided is lowered. 
     In response, in the rotor  20  of the present embodiment, the outer peripheral iron core portion  46  is formed in such a manner that in a state in which the multiple thin plate members  56  are stacked on each other in the axial direction, the raised portions  56   b  of the thin plate members  56  forming the side surface holding portions  74  on inner peripheral surfaces of the thin plate members  56  are joined and bonded along the axial direction by welding or adhesive bonding. In this manner, the outer peripheral iron core portion  46  is integrated. In this case, the thin plate members  56  are bonded at a thick portion of the outer peripheral iron core portion  46 . 
     Thus, the rotor  20  of the present embodiment has strength increased as compared to a configuration in which the thin plate members  56  are not joined to each other. Moreover, in the present embodiment, in the case of bonding the thin plate members  56  to each other, no bonding such as welding is performed on the tubular body portion  72  side (the outer peripheral side) of the outer peripheral iron core portion  46 . Thus, in the rotor  20  of the present embodiment, lowering of the strength on the tubular body portion  72  side is suppressed. Moreover, disturbance in the magnetic flux flow due to the skin effect is reduced. Thus, the rotor  20  of the present embodiment can ensure favorable magnetic properties. The side surface holding portions  74  and the axial end surface holding portions  76  of the magnet holding portions  70  as the thick portion of the outer peripheral iron core portion  46  are present at portions on which the stress on the claw-shaped magnetic pole portions  44  or the permanent magnets  49  due to the centrifugal force generated in association with rotation of the rotor  20  is concentrated. Thus, in the present embodiment, the strength of the rotor  20  is reinforced by the magnet holding portions  70 . 
     In the rotor  20  of the present embodiment, the magnet holding portion  70  holding the permanent magnet  49  has the side surface holding portions  74  and the axial end surface holding portions  76 . The side surface holding portions  74  are arranged along the side surfaces  58   n ,  58   s  of the permanent magnet  49 . The axial end surface holding portions  76  are arranged along the axial end surfaces  78   w ,  78   e  of the permanent magnet  49 . Thus, the rotor  20  of the present embodiment can provide the detachment prevention function of preventing detachment of the permanent magnets  49  in the circumferential direction using the side surface holding portions  74  of the magnet holding portions  70 . Moreover, the axial end surface holding portions  76  can provide the detachment prevention function of preventing detachment of the permanent magnets  49  in the axial direction. 
     In particular, end portions of the permanent magnet  49  in the axial direction are low-permeance portions where the magnetic flux is less circulated. Thus, there is a probability that magnetizing current necessary for magnetizing the permanent magnet  49  is increased. In response, in the rotor  20  of the present embodiment, the axial end surface holding portions  76  as the iron core are, as described above, arranged along the axial end surfaces  78   w ,  78   e  of the permanent magnet  49 . Thus, in the rotor  20  of the present embodiment, the permeance of the magnetic circuit passing through the permanent magnets  49  is increased due to the presence of the axial end surface holding portions  76 . Moreover, in the rotor  20  of the present embodiment, the magnetizing current for magnetizing the permanent magnets  49  can be reduced while such magnetization of the permanent magnets  49  can be ensured. 
     In the rotor  20  of the present embodiment, the outer peripheral iron core portion  46  includes the cylindrical divided iron core portions  46 - 1 ,  46 - 2  divided in half in the axial direction. The first divided iron core portion  46 - 1  has the pairs of side surface holding portions  74   a - 1 ,  74   a - 2  and the axial end surface holding portions  76   a - 1  of the first magnet holding portions  70   a  and the axial end surface holding portions  76   b - 1  of the second magnet holding portions  70   b . In addition, the second divided iron core portion  46 - 2  has the axial end surface holding portions  76   a - 2  of the first magnet holding portions  70   a  and the pairs of side surface holding portions  74   b - 1 ,  74   b - 2  and the axial end surface holding portions  76   b - 2  of the second magnet holding portions  70   b.    
     The side surface holding portions  74   a - 1 ,  74   a - 2  formed at the first divided iron core portion  46 - 1  extend in the counterclockwise spiral direction. Moreover, the side surface holding portions  74   b - 1 ,  74   b - 2  formed at the second divided iron core portion  46 - 2  extend in the clockwise spiral direction. Assembly of the outer peripheral iron core portion  46  with the outer periphery of the claw-shaped magnetic pole portions  44  is performed in such a manner that the first divided iron core portion  46 - 1  is inserted from a first side (the lower side in  FIG. 6 ) of the claw-shaped magnetic pole portion  44  in the axial direction while rotating in the counterclockwise spiral direction. Moreover, the second divided iron core portion  46 - 2  is inserted from a second side (the upper side in  FIG. 6 ) of the claw-shaped magnetic pole portion  44  in the axial direction while rotating in the clockwise spiral direction. Then, after such insertion has been completed, the first divided iron core portion  46 - 1  and the second divided iron core portion  46 - 2  are bonded by, e.g., adhesive bonding or welding at the center position of the outer peripheral iron core portion  46  in the axial direction. 
     In insertion of the outer peripheral iron core portion  46  onto the outer periphery of the claw-shaped magnetic pole portions  44 , both of the first divided iron core portion  46 - 1  and the second divided iron core portion  46 - 2  may be inserted from only either one of a first side and a second side of the claw-shaped magnetic pole portion  44  in the axial direction. For example, the first divided iron core portion  46 - 1  to be arranged on a first side (the lower side in  FIG. 6 ) of the claw-shaped magnetic pole portion  44  in the axial direction is first inserted from a second side (the upper side in  FIG. 6 ) of the claw-shaped magnetic pole portion  44  in the axial direction while rotating in the counterclockwise spiral direction. After such insertion has been completed, the second divided iron core portion  46 - 2  to be arranged on the second side (the upper side in  FIG. 6 ) of the claw-shaped magnetic pole portion  44  in the axial direction is inserted while rotating in the clockwise spiral direction. 
     In this structure of the rotor  20 , each of the first divided iron core portion  46 - 1  and the second divided iron core portion  46 - 2  is, in the present embodiment, inserted and arranged on the claw-shaped magnetic pole portions  44 , and are bonded to each other at the center position of the outer peripheral iron core portion  46  in the axial direction. Thus, in the present embodiment, even when the claw-shaped magnetic pole portions  44  attempt to rotate in any direction of the circumferential direction relative to the outer peripheral iron core portion  46  including the first divided iron core portion  46 - 1  and the second divided iron core portion  46 - 2 , such relative rotation is blocked. That is, when the claw-shaped magnetic pole portions  44  attempt to rotate relative to the outer peripheral iron core portion  46  in a direction in which rotation relative to the first divided iron core portion  46 - 1  is allowed, such rotation is blocked by the presence of the second divided iron core portion  46 - 2 . Moreover, when the claw-shaped magnetic pole portions  44  attempt to rotate relative to the outer peripheral iron core portion  46  in a direction in which rotation relative to the second divided iron core portion  46 - 2  is allowed, such rotation is blocked by the presence of the first divided iron core portion  46 - 1 . 
     Thus, the rotor  20  of the present embodiment can provide the anti-rotation function of preventing the claw-shaped magnetic pole portions  44  from rotating relative to the outer peripheral iron core portion  46  after the outer peripheral iron core portion  46  has been arranged and assembled on the outer peripheral side of the claw-shaped magnetic pole portions  44 . 
     The stress on the claw-shaped magnetic pole portions  44  or the permanent magnets  49  due to the centrifugal force is concentrated on tip ends of the claw-shaped magnetic pole portions  44  in the axial direction. Thus, stress acting on the center position in the axial direction is relatively small. Consequently, lowering of the strength of the rotor  20  can be suppressed in the structure in which the first divided iron core portion  46 - 1  and the second divided iron core portion  46 - 2  of the outer peripheral iron core portion  46  are bonded at the center position in the axial direction by adhesive bonding or welding as in the present embodiment. 
     In a case where the field winding  48  or the stator winding  62  is fixed by varnish application and curing and the shape of the field winding  48  or the stator winding  62  is fixed accordingly, the following method may be employed. A device configured to apply varnish executes the fixing step of fixing the winding  48 ,  62  by means of the varnish and the bonding step of bonding the first divided iron core portion  46 - 1  and the second divided iron core portion  46 - 2  by means of the varnish. The fixing step and the bonding step may be executed at the substantially same timing. According to this configuration, a device configured to manufacture the rotor  20  and the step of manufacturing the rotor  20  are simplified. 
     As clearly seen from description above, the rotor  20  of the present embodiment includes the multiple claw-shaped magnetic pole portions  44 ,  44 - 1 ,  44 - 2 , the permanent magnets  49 ,  49   a ,  49   b , and the tubular outer peripheral iron core portion  46 . The claw-shaped magnetic pole portions  44 ,  44 - 1 ,  44 - 2  face the stator  24  in the radial direction, are arranged with the clearance spaces  54 ,  54   a ,  54   b  in the circumferential direction, and are alternately magnetized to different magnetic polarities in the circumferential direction by power application to the field winding  48 . The permanent magnets  49 ,  49   a ,  49   b  are each arranged in the clearance spaces  54 ,  54   a ,  54   b  such that the polarity of each of the side surfaces  58   n ,  58   s  facing the claw-shaped magnetic pole portions  44 ,  44 - 1 ,  44 - 2  in the circumferential direction is the same as the polarity of a corresponding one of the claw-shaped magnetic pole portions  44 ,  44 - 1 ,  44 - 2 . The outer peripheral iron core portion  46  covers the outer peripheral side of the claw-shaped magnetic pole portions  44 ,  44 - 1 ,  44 - 2 . The outer peripheral iron core portion  46  has the tubular body portion  72  and the magnet holding portions  70 ,  70   a ,  70   b  holding the permanent magnets  49 ,  49   a ,  49   b.    
     According to this configuration, in the rotor  20  of the present embodiment, the permanent magnet  49  can be held between adjacent ones of the claw-shaped magnetic pole portions  44  by the magnet holding portion  70  of the outer peripheral iron core portion  46 . Moreover, the magnet holding portion  70  is arranged as the iron core along the surfaces of the permanent magnet  49 , and closely contacts such a permanent magnet  49 . Thus, in the rotor  20  of the present embodiment, the magnetic resistance of the magnetic circuit passing through the permanent magnets  49  can be more reduced as compared to a structure in which the magnet holding portion  70  is formed from the non-magnetic body or a structure in which a large gap is formed between the permanent magnet  49  and the claw-shaped magnetic pole portion  44 . Thus, in the rotor  20  of the present embodiment, the permanent magnet  49  is held between adjacent ones of the claw-shaped magnetic pole portions  44  by the magnet holding portion  70  while the permeance of the magnetic circuit passing through the permanent magnets  49  is increased. 
     Moreover, in the rotor  20  of the present embodiment, the magnet holding portion  70  is formed to protrude from the inner peripheral surface of the tubular body portion  72  of the outer peripheral iron core portion  46  toward the radial outside and to grip the permanent magnet  49 . According to this configuration, the rotor  20  of the present embodiment can grip and hold the permanent magnet  49  between adjacent ones of the claw-shaped magnetic pole portions  44  by the magnet holding portion  70  protruding from the inner peripheral surface of the tubular body portion  72  of the outer peripheral iron core portion  46  toward the radial inside. 
     Further, in the rotor  20  of the present embodiment, the outer peripheral iron core portion  46  has such a structure that the soft magnetic thin plate members  56  are stacked on each other in the axial direction. The outer peripheral iron core portion  46  is integrated in such a manner that the thin plate members  56  are bonded together along the axial direction at the magnet holding portions  70 . According to this configuration, in the rotor  20  of the present embodiment, bonding of the thin plate members  56  by welding etc. is not performed on the outer peripheral side of the outer peripheral iron core portion  46 . Thus, in the rotor  20  of the present embodiment, disturbance in the magnetic flux flow due to the skin effect is reduced, and favorable magnetic properties can be ensured. The magnet holding portions  70  as the thick portion of the outer peripheral iron core portion  46  are present at the portions on which the stress due to the centrifugal force in association with rotation of the rotating electrical machine  22  is concentrated. Thus, in the present embodiment, the strength of the rotor  20  is reinforced. 
     In the rotor  20  of the present embodiment, the magnet holding portion  70  has the side surface holding portions  74  facing the side surfaces  58   n ,  58   s  of the permanent magnet  49  and extending along the axial direction. According to this configuration, the rotor  20  of the present embodiment can hold the permanent magnets  49  in the circumferential direction using the side surface holding portions  74 . 
     In the rotor  20  of the present embodiment, the claw-shaped magnetic pole portions  44  have the first claw-shaped magnetic pole portions  44 - 1  and the second claw-shaped magnetic pole portions  44 - 2 . The first claw-shaped magnetic pole portions  44 - 1  and the second claw-shaped magnetic pole portions  44 - 2  are formed such that the circumferential width changes from the base side in the axial direction to the tip end side in the axial direction. Moreover, the first claw-shaped magnetic pole portions  44 - 1  and the second claw-shaped magnetic pole portions  44 - 2  are alternately arranged in the circumferential direction such that the position of the base side in the axial direction and the position of the tip end side in the axial direction are on the opposite sides in the axial direction, and are magnetized to different magnetic polarities. The clearance spaces  54  have the first clearance spaces  54   a  and the second clearance spaces  54   b . The first clearance spaces  54   a  and the second clearance spaces  54   b  are inclined from a first side to a second side in the axial direction at the predetermined angle with respect to the rotation axis. Moreover, the first clearance spaces  54   a  and the second clearance spaces  54   b  are provided in different skew directions inclined with respect to the rotation axis. The outer peripheral iron core portion  46  has such a structure that the cylindrical first divided iron core portion  46 - 1  and the cylindrical second divided iron core portion  46 - 2  divided in half in the axial direction are bonded at the center position in the axial direction. The first divided iron core portion  46 - 1  has the side surface holding portions  74   a - 1 ,  74   a - 2  holding the first permanent magnets  49   a  arranged in the first clearance spaces  54   a . The second divided iron core portion  46 - 2  has the side surface holding portions  74   b - 1 ,  74   b - 2  holding the second permanent magnets  49   b  arranged in the second clearance spaces  54   b.    
     According to this configuration, in the rotor  20  of the present embodiment, each of the permanent magnets  49   a ,  49   b  arranged in the first clearance spaces  54   a  and the second clearance spaces  54   b  in different skew directions inclined with respect to the rotation axis is held by the side surface holding portions  74   a - 1 ,  74   a - 2 ,  74   b - 1 ,  74   b - 2  of the divided iron core portions  46 - 1 ,  46 - 2  as separated bodies divided in half in the axial direction. 
     In the rotor  20  of the present embodiment, the first divided iron core portion  46 - 1  is formed such that the first permanent magnet  49   a  is held by the side surface holding portions  74   a - 1 ,  74   a - 2  in a state in which the first divided iron core portion  46 - 1  is inserted onto the claw-shaped magnetic pole portions  44  by rotation in the counterclockwise spiral direction corresponding to the skew direction of the first clearance space  54   a . The second divided iron core portion  46 - 2  is formed such that the second permanent magnet  49   b  is held by the side surface holding portions  74   b - 1 ,  74   b - 2  in a state in which the second divided iron core portion  46 - 2  is inserted onto the claw-shaped magnetic pole portions  44  by rotation in the clockwise spiral direction corresponding to the skew direction of the second clearance space  54   b.    
     According to this configuration, in the rotor  20  of the present embodiment, each of the first divided iron core portion  46 - 1  and the second divided iron core portion  46 - 2  divided in half in the axial direction can be inserted onto the claw-shaped magnetic pole portions  44  by rotation in the spiral direction (specifically the spiral directions opposite to each other) corresponding to the skew direction of the clearance space  54 , and both of the divided iron core portions  46 - 1 ,  46 - 2  can be bonded at the center position in the axial direction. Moreover, the rotor  20  of the present embodiment can provide the anti-rotation function of preventing the claw-shaped magnetic pole portions  44  from rotating in the circumferential direction relative to the outer peripheral iron core portion  46  including the first divided iron core portion  46 - 1  and the second divided iron core portion  46 - 2  after bonding of both of the divided iron core portions. 
     In the rotor  20  of the present embodiment, the magnet holding portion  70  has the axial end surface holding portions  76  facing the axial end surfaces  78   w ,  78   e  of the permanent magnet  49  and extending along the circumferential direction. According to this configuration, in the rotor  20  of the present embodiment, the permanent magnet  49  can be held in the axial direction using the axial end surface holding portions  76 . 
     In the above-described embodiment, the outer peripheral iron core portion  46  has such a structure that the multiple soft magnetic thin plate members  56  such as the magnetic steel sheets are stacked on each other in the axial direction. However, the technique of the present disclosure is not limited to above. The outer peripheral iron core portion  46  may have, for example, a structure in which a stack in the axial direction is formed in such a manner that a single soft magnetic linear member  100  (see  FIG. 10 ) or a single band-shaped member  102  (see  FIG. 11 ) is spirally wound about the axis. That is, the outer peripheral iron core portion  46  may be formed from the soft magnetic linear member  100  or the band-shaped member  102  spirally wound to form the stack in the axial direction. In this case, the linear member  100  or the band-shaped member  102  is spirally wound about the axis on the outer peripheral side of the claw-shaped magnetic pole portions  44  while turns of the linear member  100  or the band-shaped member  102  are arranged with no clearances or slight clearances in the axial direction. 
     In the above-described variation, the single linear member  100  or the single band-shaped member  102  may be formed as follows. Specifically, the single linear member  100  or the single band-shaped member  102  may be formed such that portions corresponding to the magnet holding portions  70  are provided at corresponding portions and are arranged diagonally in the axial direction upon spiral winding. Moreover, in this configuration, stacked portions of the linear member  100  or stacked portions of the band-shaped member  102  at the magnet holding portions  70  may be bonded along the axial direction to integrate the outer peripheral iron core portion  46 . Further, in this configuration, tension of the linear member  100  or the band-shaped member  102  is held constant at the manufacturing step of winding the linear member  100  or the band-shaped member  102  around the outer peripheral side of the claw-shaped magnetic pole portions  44 . Thus, both of the quality and productivity of the rotor  20  are ensured. Note that the linear member  100  or the band-shaped member  102  forming the outer peripheral iron core portion  46  is preferably a block having a rectangular section, considering the strength and the magnetic performance. However, the present disclosure is not limited to above. For example, the linear member  100  or the band-shaped member  102  may be in a round wire shape or a shape with curved corner portions. 
     In the above-described embodiment, the outer peripheral iron core portion  46  has such a structure that the thin plate members  56  are stacked in the axial direction. Moreover, the outer peripheral iron core portion  46  is, as a whole, formed in a cylindrical shape, and has the magnet holding portions  70  on the inner peripheral side. However, the technique of the present disclosure is not limited to above. The outer peripheral iron core portion  46  may be formed from a cylindrical member configured such that components are integrated in the axial direction, and may have the magnet holding portions  70  on the inner peripheral side. 
     In the above-described embodiment, the following configuration is employed. Specifically, the outer peripheral iron core portion  46  has such a structure that the multiple thin plate members  56  are stacked on each other in the axial direction. Each of the thin plate members  56  has the raised portions  56   b  corresponding to the side surface holding portions  74  of the magnet holding portion  70  and the raised portion  56   c  corresponding to the axial end surface holding portion  76 . The magnet holding portion  70  is provided integrally with the inner peripheral surface of the tubular body portion  72  of the outer peripheral iron core portion  46 , and the magnet holding portions  70  and the tubular body portion  72  are formed from the single component. However, the technique of the present disclosure is not limited to above. 
     In a variation having the above-described configuration, a magnet holding portion  110  for holding the permanent magnet  49  and the tubular body portion  72  may be formed from different components as illustrated in  FIGS. 12 and 13  by way of example without the thin plate members  56  of the outer peripheral iron core portion  46  having the raised portions  56   b ,  56   c , for example. Specifically, the tubular body portion  72  has such a structure that the multiple thin plate members  56  are stacked on each other in the axial direction. The magnet holding portion  110  is not necessarily formed from the multiple thin plate members  56 . The magnet holding portion  110  may extend along the axial direction, and may be formed from a component (e.g., a component formed with a U-shaped section) formed separately from the tubular body portion  72 . That is, the magnet holding portion  110  (particularly the side surface holding portions  74 ) may extend inclined with respect to the rotation axis of the rotor  20 , and the entirety of the magnet holding portion  110  may be formed integrally. Note that in this structure, the axial end surface holding portions  76  may be formed integrally with the side surface holding portions  74 . The magnet holding portion  110  is, by welding, adhesive bonding, etc., bonded to the inner peripheral surface of the tubular body portion  72  configured such that the thin plate members  56  are stacked on each other in the axial direction. 
     The magnet holding portion  110  has a pair of side surface holding portions  112  corresponding to the side surface holding portions  74  of the magnet holding portion  70 , a pair of axial end surface holding portions (not shown) corresponding to the axial end surface holding portions  76  of the magnet holding portion  70 , and a flat plate-shaped base portion  114  joined in contact with the inner peripheral surface of the tubular body portion  72 . The side surface holding portions  112  in a pair face each other with respect to the base portion  114  in the circumferential direction. Moreover, the axial end surface holding portions in a pair face each other with respect to the base portion  114  in the axial direction. 
     The magnet holding portion  110  and the tubular body portion  72  may be made of different materials. Alternatively, the magnet holding portion  110  and the tubular body portion  72  may be made of the same material. When the magnet holding portion  110  and the tubular body portion  72  are made of the same material, the magnet holding portion  110  and the tubular body portion  72  are produced by different steps, and have different structures. 
     If the thin plate member  56  has, as in the above-described embodiment, the raised portions  56   b  corresponding to at least the side surface holding portions  74  of the magnet holding portion  70  and the magnet holding portions  70  and the tubular body portion  72  are formed from a single component, a step in manufacturing of the outer peripheral iron core portion  46  provided with the magnet holding portions  70  can be simplified. However, in order for the raised portions  56   b  to be formed on an inner peripheral side of the thin plate members  56 , circular ring members need to be punched out such that the raised portions  56   b  are formed. Thus, after punching out, each portion (shaded portions in  FIG. 14 ) between adjacent ones of the raised portions  56   b  is an unnecessary portion. Thus, the yield rate when producing the outer peripheral iron core portion  46  is lowered. 
     On the other hand, in the above-described variation, the magnet holding portion  110  and the tubular body portion  72  of the outer peripheral iron core portion  46  are formed from different components as described above. Thus, the raised portions  56   b  corresponding to the magnet holding portions  110  are not necessarily formed on the inner peripheral side of the thin plate members  56 . Consequently, the circular ring members as the material of the thin plate members  56  do not need to be punched out such that the raised portions  56   b  are formed. With this configuration, in the present variation, waste material upon formation of the outer peripheral iron core portion  46  can be reduced, and the yield rate when producing the outer peripheral iron core portion  46  can be improved. Moreover, in the present variation, the material of the linear member  100  and the material of the tubular body portion  72  can be changed as necessary. 
     In the above-described embodiment, the magnet holding portion  70  is formed to protrude from the inner peripheral surface of the tubular body portion  72  of the outer peripheral iron core portion  46  toward the radial inside, and the permanent magnet  49  is formed in the substantially rectangular parallelepiped shape. However, the technique of the present disclosure is not limited to above. As illustrated in  FIG. 15  by way of example, the magnet holding portion  70  is formed with a tapered section to divide a space between the permanent magnet  49  and the tubular body portion  72  of the outer peripheral iron core portion  46  into an internal space  120  where the permanent magnet  49  is held and a predetermined space  122  formed on the outside of the internal space  120  in the radial direction. The claw-shaped magnetic pole portion  44  has a tapered portion  124  arranged to fill the predetermined space  122 . 
     The pair of side surface holding portions  74   a - 1 ,  74   a - 2  of the magnet holding portion  70  may be formed such that a distance L between positions continuously connected to the tubular body portion  72  of the outer peripheral iron core portion  46  is shorter than a distance (an opening distance) between inner tip ends of the side surface holding portions  74   a - 1 ,  74   a - 2  in the radial direction and is shorter than the circumferential width W of the permanent magnet  49 . Alternatively, the tapered portion  124  of the claw-shaped magnetic pole portion  44  may be provided at each end of the claw-shaped magnetic pole portion  44  in the circumferential direction on the radial outside. Alternatively, the circumferential width W may be formed greater toward the radial outside. 
     In the above-described variation, the permanent magnet  49  (particularly corner portions on the radial outside) is supported in contact with inner wall surfaces of the side surface holding portions  74  in the internal space  120 , the tapered portion  124  of the claw-shaped magnetic pole portion  44  being present on the outside of the internal space  120  in the radial direction. Thus, in the present variation, even when the stress on the permanent magnet  49  due to the centrifugal force in association with rotation of the rotating electrical machine  22  is generated, such stress is also provided not only to the outer peripheral iron core portion  46  but also to the tapered portion  124  of the claw-shaped magnetic pole portion  44 . 
     Thus, in the above-described variation, the stress on the permanent magnet  49  due to the centrifugal force is dispersed to the outer peripheral iron core portion  46  and the claw-shaped magnetic pole portions  44 . Consequently, in the present variation, the strength of the rotor  20  is improved. Alternatively, in the present variation, the width of the tubular body portion  72  of the outer peripheral iron core portion  46  in the radial direction can be decreased within a range where predetermined strength is ensured. A smaller width of the tubular body portion  72  of the outer peripheral iron core portion  46  in the radial direction results in a smaller amount of material injected upon formation of the outer peripheral iron core portion  46 . Moreover, the magnetic flux leaking from the outer peripheral iron core portion  46  is decreased. 
     In the above-described embodiment, the permanent magnet  49  arranged in each clearance space  54  between adjacent ones of the claw-shaped magnetic pole portions  44  has a single structure formed in the substantially rectangular parallelepiped shape. However, the technique of the present disclosure is not limited to above. As illustrated in  FIGS. 16 and 17  by way of example, the permanent magnet  49  for each clearance space  54  may be divided into two or more magnets in the circumferential direction by a q-axis at a position shifted from a d-axis passing through the center of the claw-shaped magnetic pole portion  44  in the circumferential direction by an electrical angle of 90°. That is, the permanent magnet  49  may include multiple divided magnets  130 . 
     In the above-described variation, the magnet holding portion  70  of the outer peripheral iron core portion  46  is formed to hold the permanent magnet  49  including the multiple divided magnets  130  and to surround the claw-shaped magnetic pole portion  44  from the radial inside. Moreover, the magnet holding portion  70  is formed to have an iron core portion at which a q-axis magnetic circuit passing through the q-axis is formed. This is suitable for generation of reluctance torque. That is, the magnet holding portion  70  may have the side surface holding portions  74 , a partition portion  132 , and an annular portion  134 . The side surface holding portion  74  contacts the side surface  58   n ,  58   s  of the permanent magnet  49  facing the claw-shaped magnetic pole portion  44 . The partition portion  132  extends, between the divided magnets  130  divided in the circumferential direction, in the radial direction to penetrate the permanent magnet  49 . The annular portion  134  extends in the circumferential direction to couple inner ends of the partition portions  132  in the radial direction. The partition portions  132  and the annular portion  134  form an iron core portion formed to surround the claw-shaped magnetic pole portion  44  and forming the q-axis magnetic circuit passing through the q-axis. 
     As illustrated in  FIG. 18  by way of example, the magnet holding portion  70  is provided integrally with the outer peripheral iron core portion  46 . The permanent magnet  49  includes the divided magnets  130  divided in half in the circumferential direction at the q-axis. The partition portion  132  of the magnet holding portion  70  extends in the radial direction to pass between the divided magnets  130  divided in half. Such a configuration may be employed. 
     As illustrated in  FIG. 19  by way of example, the magnet holding portion  70  is formed separately from the tubular body portion  72  of the outer peripheral iron core portion  46 . The permanent magnet  49  includes the divided magnets  130  divided in half in the circumferential direction at the q-axis. The partition portion  132  of the magnet holding portion  70  extends in the radial direction to pass between the divided magnets  130  divided in half. Such a configuration may be employed. 
     As illustrated in  FIG. 20  by way of example, the magnet holding portion  70  is formed separately from the tubular body portion  72  of the outer peripheral iron core portion  46 . The permanent magnet  49  includes the divided magnets  130  divided into three magnets in the circumferential direction at the q-axis. Two partition portions  132  of the magnet holding portion  70  are, corresponding to the divided magnets  130  divided into three magnets, provided next to each other in the circumferential direction. Moreover, the partition portion  132  extends in the radial direction to pass between each two adjacent divided magnets  130 . Such a configuration may be employed. 
     In the above-described variation, the divided magnet  130  is arranged and sandwiched between the side surface holding portion  74  and the partition portion  132  or between the partition portions  132 . With this configuration, the permanent magnet  49  can be held between the claw-shaped magnetic pole portions  44  in this variation. Moreover, the q-axis magnetic circuit magnetically isolated from a d-axis magnetic circuit can be formed on the q-axis by means of the magnet holding portion  70  (particularly the partition portion  132  and the annular portion  134 ), and therefore, the reluctance torque is generated to improve the torque in the present variation. 
     Further in the above-described variation, the annular portion  134  of the magnet holding portion  70  has such a double structure that a space  140  is formed as illustrated in  FIG. 17  by way of example. Moreover, in the present variation, a permanent magnet  142  is arranged in the space  140  on the inside of the annular portion  134  arranged on the inside of the claw-shaped magnetic pole portion  44  in the radial direction. The permanent magnet  142  is held together with the claw-shaped magnetic pole portion  44  by the magnet holding portion  70 . The permanent magnet  142  is configured such that a permanent magnet orientation direction is deviated to the side of the rotor  20  in the radial direction. Thus, the permanent magnet  142  more efficiently outputs magnetic force as compared to the divided magnet  130 . In the divided magnet  130 , a magnetic flux direction is toward the d-axis center of the claw-shaped magnetic pole portion  44 . A magnetic flux is branched into a magnetic path toward the annular portion  134  gripping the magnetic with high magnetic resistance and a magnetic path toward the stator iron core  60  with lower magnetic resistance than that described above. Thus, the magnetic flux flows in the stator iron core  60  while a magnetic flux direction of the permanent magnet  142  is also directed to the stator iron core  60 . Consequently, action similar to that of the divided magnet  130  is generated by a smaller number of magnets than the divided magnets  130 . 
     The technique of the present disclosure is not limited to the above-described embodiment and variations. Various changes can be made without departing from the gist of the present disclosure. 
     REFERENCE SIGNS LIST 
     
         
           20  . . . rotating electrical machine rotor 
           22  . . . rotating electrical machine 
           24  . . . stator 
           40  . . . boss portion 
           42  . . . disc portion 
           44  . . . claw-shaped magnetic pole portion 
           44 - 1  . . . first claw-shaped magnetic pole portion 
           44 - 2  . . . second claw-shaped magnetic pole portion 
           46  . . . outer peripheral iron core portion 
           46 - 1  . . . first divided iron core portion 
           46 - 2  . . . second divided iron core portion 
           48  . . . field winding 
           49  . . . permanent magnet 
           49   a  . . . first permanent magnet 
           49   b  . . . second permanent magnet 
           50  . . . rotary shaft 
           54  . . . clearance space 
           54   a  . . . first clearance space 
           54   b  . . . second clearance space 
           56  . . . thin plate member 
           58   n  . . . side surface (N-pole side) 
           58   s  . . . side surface (S-pole side) 
           70 ,  110  . . . magnet holding portion 
           70   a  . . . first magnet holding portion 
           70   b  . . . second magnet holding portion 
           72  . . . tubular body portion 
           74   a - 1 ,  74   a - 2 ,  74   b - 1 ,  74   b - 2 ,  112  . . . side surface holding portion 
           76   a - 1 ,  76   a - 2 ,  76   b - 1 ,  76   b - 2  . . . axial end surface holding portion 
           78   w ,  78   e  . . . axial end surface 
           100  . . . linear member 
           102  . . . band-shaped member 
           120  . . . internal space 
           122  . . . predetermined space 
           124  . . . tapered portion 
           130  . . . divided magnet