Patent Publication Number: US-10763714-B2

Title: Motor

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application is a continuation application of U.S. patent application Ser. No. 15/052,285, filed on Feb. 24, 2016, the entire contents of which are incorporated herein by reference and priority to which is hereby claimed. The present invention claims priority under 35 U.S.C. § 119 to Japanese Application No. 2015-039134 filed Feb. 27, 2015, the entire content of which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present disclosure relates to a motor. 
     BACKGROUND 
     For example, Japanese Patent Application Publication No. H07-312852 discloses a permanent magnet type rotor, which is an integrated unit of a permanent magnet, a yolk part, and a shaft, formed by resin molding. 
     In the permanent magnet type rotor described above, there has been a risk of demagnetization when the integrated unit is formed by resin molding, due to the heat of the resin. In order to overcome such risk, disposing the permanent magnet between the yolk part after the yolk part (core piece part) is formed into an integrated unit by resin molding can be considered. When such method is employed, the permanent magnet is attached to either side of the neighboring yolk parts by using magnetic force. 
     However, it is difficult to intentionally attach a permanent magnet, which is disposed between the yolk part, to one side of the neighboring yolk part in a circumferential direction. For this reason, the location of the permanent magnet in the yolk part may vary per each permanent magnet, and the location of the permanent magnet in the circumferential direction may become irregular. Consequently, the magnetic flux generated by the permanent magnet becomes uneven, and further, the center of gravity balance in the circumferential direction of the permanent magnet type rotor becomes deteriorated. As a result, the rotation of the permanent magnet type rotor becomes unstable, and vibration and noise have been generated when the permanent magnet type rotor rotates. 
     SUMMARY 
     One example of the present disclosure is a motor comprising a rotor which has a shaft having its center on a vertically extended center axis, a stator which is disposed at a radially outer side of the rotor, and a bearing which supports the shaft, the rotor having a plurality of core pieces arranged on a radially outer side of the shaft in a circumferential direction, a plurality of permanent magnets to magnetize the core piece part, a mold resin part made of resin and disposed between the plurality of core pieces, and an interposed part in contact with a surface on one side in a circumferential direction of each of the core pieces, the neighboring core pieces having a magnet insertion hole provided therebetween in a circumferential direction, extended in an axial direction for insertion of the permanent magnet, the permanent magnet having two magnetic poles arranged along a circumferential direction, the magnetic poles of the circumferentially neighboring permanent magnets facing each other having identical polarity, in which each of the permanent magnets is in indirect contact with the core piece positioned on the other side in the circumferential direction of the magnet insertion hole via the interposed part. 
     According to one example of the present disclosure, it is possible to inhibit the vibration and the noise caused by the rotation of the rotor. 
     The above and other elements, features, steps, characteristics and advantages will become more apparent from the following detailed description of the embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments will now be described, by way of example only, with reference to the accompanying drawings which are meant to be exemplary, not limiting, and wherein like elements are numbered alike in several Figures, in which: 
         FIG. 1  is a cross-sectional view of a motor of a first exemplary embodiment. 
         FIG. 2  is a perspective view of the motor or the first exemplary embodiment. 
         FIG. 3  is a perspective view of a rotor of the first exemplary embodiment. 
         FIG. 4  is a cross-sectional view of the rotor of the first exemplary embodiment, and shows a cross section of IV-IV from  FIG. 1 . 
         FIG. 5  illustrates the rotor of the first exemplary embodiment, and is a partially enlarged view of  FIG. 4 . 
         FIG. 6  is a perspective view of a portion of the rotor of the first exemplary embodiment. 
         FIG. 7  is a cross-sectional view of a first guide part and a second guide part of the first exemplary embodiment. 
         FIG. 8  is a cross-sectional view of the first guide part and the second guide part of the first exemplary embodiment. 
         FIG. 9  is a partially enlarged view of another example of the rotor of the first exemplary embodiment. 
         FIG. 10  is a partially enlarged view of another example of the rotor of the first exemplary embodiment. 
         FIG. 11  is a partially enlarged view of another example of the rotor of the first exemplary embodiment. 
         FIG. 12  is a cross-sectional view of a rotor of a second exemplary embodiment. 
         FIG. 13  illustrates the rotor of the second exemplary embodiment, and is a partially enlarged view of  FIG. 12 . 
     
    
    
     DETAILED DESCRIPTION 
     Herein, a motor according to an exemplary embodiment of the present disclosure will be described with reference to the drawings. The scope of the present disclosure is not limited to the below embodiment, and can be appropriately altered within the scope of technical idea of the present disclosure. The following drawings may have vast difference in the dimension of each structure from the actual structure, in order to clearly illustrate each constitution. 
     In the drawings, an X-Y-Z coordinate system is provided as an appropriate 3-dimensional orthogonal coordinates system. In the X-Y-Z coordinate system, a direction parallel to the axial direction of the center axis J 1  shown in  FIG. 1  is referred to as the z-axis direction. A direction perpendicular to the z-axis direction, that is, the left and right directions of  FIG. 1 , is referred to as the x-axis direction. A direction perpendicular to both the x-axis direction and the z-axis direction is referred to as the y-axis direction. Also, a circumferential direction having its center on the center axis J is referred to as the θZ direction. As to the θZ direction, a clockwise direction when viewed toward the +Z side from the −Z side is referred to as the positive direction, and a counter clockwise direction when viewed toward the +Z side from the −Z side is referred to as the negative direction. 
     Herein, a direction extended from the center axis J (z-axis direction) is referred to as the vertical direction. The positive side of the z-axis direction (+Z side) is referred to as the “upper side (axial upper side)”, and the negative side of the z-axis direction (−Z side) is referred to as the “lower side”. It is to be understood that the descriptions of the vertical direction, upper side and the lower side are used for explanation only, and they do not limit the actual positional relation or direction. Also, unless otherwise explained, a direction parallel to the center axis J (z-axis direction) is simply referred to as the “axial direction”, a radial direction having its center on the center axis J is simply referred to as the “radial direction”, and a circumferential direction having its center on the center axis J (θZ direction), that is, the axial circumference of center axis J, is simply referred to as the “circumferential direction”. 
     Further, a direction along the positive direction of the θZ direction (+θZ side, one circumferential direction) is referred to as the “driving side”, and the direction along the negative direction of the θZ direction (−θZ side, other circumferential direction) is referred to as the “counter driving side”. Also, the descriptions of the driving side and counter driving side are used for explanation only, and they do not limit the actual driving direction. 
     In the present description, being axially extended refers to a strict meaning of being extended in an axial direction (z-axis direction), but it may also include the meaning of being extended in an axial direction inclined within a range of 45° or less. Also in the present description, being radially extended refers to a strict meaning of being extended in a radial direction, that is, a direction perpendicular to the axial direction (z-axis direction), but in may also include the meaning of being extended in a radial direction inclined within a range of 45° or less. 
     First Embodiment 
       FIG. 1  is a cross-sectional view of a motor  10  of the present embodiment. As shown in  FIG. 1 , the motor  10  comprises a housing  20 , a rotor  30  having a shaft  31 , a stator  40 , a lower bearing  51 , an upper bearing  52 , and a bus bar unit  60 . 
     The housing  20  is a casing having a cylindrical portion. The housing  20  receives the rotor  30 , the stator  40 , the lower bearing  51 , the upper bearing  52 , and the bus bar unit  60 . The housing  20  has a lower housing  21 , and an upper housing  22 . The lower housing  21  has a cylindrical shape which is open on both sides in the axial direction (±Z side). The upper housing  22  is coupled to an end portion of the upper side (+Z side) of the lower housing  21 . The upper housing  22  covers the rotor  30  and upper side of the stator  40 . 
     The stator  40  is retained on the inside of the lower housing  21 . The stator  40  is disposed at a radially outer side of the rotor  30 . The stator  40  has a core back part  41 , a teeth part  42 , a coil  43 , and a bobbin  44 . The core back part  41  has, for example, a cylindrical shape concentric with the center axis J. The outer surface of the core back part  41  is coupled to the inner surface of the lower housing  21 . 
     The teeth part  42  is extend from the inner surface of the core back part  41  toward the shaft  31 . Although it is omitted from the drawings, a plurality of teeth parts  42  are provided, and arranged at equal spaces in the circumferential direction. The bobbin  44  is mounted on each teeth part  42 . The coil  43  is wound around each teeth part  42  via the bobbin  44 . In this embodiment, the core back part  41  and the teeth part  42  are made of a laminated steel plate which is formed by laminating a plurality of electromagnetic steel plates. 
     The bus bar unit  60  is disposed at an upper side (+Z side) of the stator  40 . The bus bar unit  60  has a connector part  62 . An outer power source, which is omitted from the drawings, is connected to the connector part  62 . The bus bar unit  60  has a wiring member which is electrically connected with the coil  43  of the stator  40 . One end of the wiring member is exposed to the exterior of the motor  10  via the connector part  62 . Accordingly, power is supplied from the outer power source to the coil  43  through the wiring member. The bus bar unit  60  has a bearing support part  61 . 
     The lower bearing  51  and the upper bearing  52  support the shaft  31 . The lower bearing  51  is disposed at a lower side (−Z side) than the stator  40 . The lower bearing  51  is retained in the lower housing  21 . The upper bearing  52  is disposed at an upper side (+Z side) than the stator  40 . The upper bearing  52  is retained in the bearing support part  61  of the bus bar unit  60 . 
     The rotor  30  has a shaft  31 , and a rotor body unit  32 . The shaft  31  has its center on the center axis J which extends in the vertical direction (z-axis direction). In this embodiment, the shaft is a member having a cylindrical shape. The shaft may be a solid type member or a hollow type cylindrical member. The rotor body unit  32  is disposed at a radially outer side of the shaft  31 . The rotor body unit  32  is coupled to an outer circumferential surface of the shaft  31 . The rotor  30  rotates, for example, in a counter clockwise direction on the center axis J when viewed from the upper side (+Z side), that is, from a counter driving side (−θZ side) to the driving side (+θZ side). 
       FIG. 2  and  FIG. 3  are perspective views of the rotor  30 .  FIG. 4  illustrates the rotor  30 , and is a cross-section of IV-IV from  FIG. 1 .  FIG. 5  is a partially enlarged view of  FIG. 4 .  FIG. 6  is a perspective view of a portion of the rotor  30 . In  FIG. 6 , illustration of the permanent magnet  33 A is omitted. 
     As shown in  FIG. 2  to  FIG. 4 , the rotor body unit  32  has a plurality of permanent magnets  33 A,  33 B, a plurality of core piece parts  34 N,  34 S, and a mold resin part  35 . That is, the rotor  30  has a plurality of permanent magnets  33 A,  33 B, a plurality of core piece parts  34 N,  34 S, and a mold resin part  35 . 
     The permanent magnets  33 A,  33 B magnetize the core piece parts  34 N,  34 S. In this embodiment, the core piece parts  34 N,  34 S are made of a laminated steel plate which is formed by laminating a plurality of electromagnetic steel plates. The electromagnetic steel plate is a type of magnetic material. As shown in  FIG. 4 , the permanent magnet  33 A and the permanent magnet  33 B are alternately arranged in the circumferential direction. Each of the permanent magnet  33 A,  33 B is inserted into a magnet insertion hole  38  which is to be described in detail later. The permanent magnets  33 A,  33 B respectively have two magnetic poles arranged in the circumferential direction. The permanent magnet  33 A has, for example, the N-pole on the driving side (+θZ side), and the S-pole on the counter driving side (−θZ side). The permanent magnet  33 B has, for example, the S-pole on the driving side (+θZ side), and the N-pole on the counter driving side (−θZ side). Accordingly, the magnetic poles of the circumferentially neighboring permanent magnets  33 A,  33 B are arranged to face each other with identical polarity. 
     The permanent magnet  33 A and the permanent magnet  33 B are configured the same way, except for the arrangement of magnetic poles in the circumferential direction. For this reason, in the following descriptions, only the permanent magnet  33 A may be explained as a representation of the permanent magnets, and explanations related to the permanent magnet  33 B may be omitted. 
     As shown in  FIG. 5 , the permanent magnet  33 A is in direct contact with the core piece part  34 S disposed on the counter driving side (−θZ side) of the magnet insertion hole  38  which is to be described in detail later. For this reason, the permanent magnet  33 A is stably attached to the core piece part  34 S by magnetic force and the permanent magnet  33 A is stably retained in the magnet insertion hole  38 . In the present embodiment, the permanent magnet  33 A is in contact with a surface on the counter driving side and a surface on the outer side of the magnet insertion hole  38  in the circumferential direction. The permanent magnet  33 A is extended in the radial direction. The shape of the cross section perpendicular to the axial direction of the permanent magnet  33 A (Z-axis direction) is, for example, quadrangular. 
     In the present description, a quadrangular shape includes a substantially quadrangular shape. A substantially quadrangular shape includes a state where the quadrangular corners are chamfered. In the example shown in  FIG. 5 , a magnet corner part  33 Aa, which is a corner portion of the driving side (+θZ side) among each corner on a radially outer side of the permanent magnet  33 A, is chamfered. 
     Also in the present description, being chamfered includes the meaning of being cut. The method of cutting is not limited in specific, and it may be either angular chamfer or round chamfer. 
     The number of the permanent magnet  33 A provided in the present embodiment is, for example, seven. The number of the permanent magnet  33 B is also, for example, seven. That is, the number of the permanent magnet  33 A and the number of the permanent magnet  33 B are identical. Also, the number of the permanent magnets  33 A,  33 B may be appropriately altered in accordance with the purpose of the motor. 
     As shown in  FIG. 4 , the core piece parts  34 N,  34 S are arranged along the circumferential direction at a radially outer side of the shaft  31 . The core piece part  34 N and the core piece part  34 S are alternately arranged along the circumferential direction. The core piece part  34 N is disposed between the N-pole of the permanent magnet  33 A and the N-pole of the permanent magnet  33 B. Accordingly, the core piece part  34 N is magnetized to the N-pole. The core piece part  34 S is disposed between the S-pole of the permanent magnet  33 A and the S-pole of the permanent magnet  33 B. Accordingly, the core piece is magnetized to the S-pole. 
     In the present embodiment, the core piece parts  34 N,  34 S are connected to each other only by the mold resin part  35 . That is, other than the mold resin part  35 , the rotor  30  does not have any other portion to connect the core piece parts  34 N,  34 S to each other, and the core piece parts  34 N,  34 S are separated. Accordingly, when the mold resin part  35  is to be shaped by a resin mold, for example, the resin may easily drip down between core piece parts  34 N,  34 S. Also, it is possible to inhibit the magnetic flux inside the core piece parts  34 N,  34 S from leaking radially inward. 
     The core piece part  34 N and the core piece part  34 S are configured the same way, except for the polarity in which they are magnetized. For this reason, in the following descriptions, only the core piece part  34 N may be explained as a representation of the core piece parts. 
     As shown in  FIG. 5 , a core piece corner  34   c , which is a corner portion of the counter driving side (−θZ side) among each corner on a radially outer side of the core piece part  34 N, is chamfered. In the present embodiment, each corner on the outer side of the core piece part  34 N in the circumferential direction is chamfered, for example, in both circumferential directions, as shown in  FIG. 4 . A radially inner end portion of the core piece part  34 N is disposed at a radially outer side than a radially inner end portion of the permanent magnet  33 A. 
     The number of the core piece part  34 N provided in the present embodiment is, for example, seven. The number of the core piece  34 S is also, for example, seven. That is, the number of the core piece part  34 N and the number of the core piece part  34 S are identical. The number of the permanent magnets  33 A,  33 B is identical to the number of the core piece parts  34 N,  34 S. Further, the number of the core piece parts  34 N,  34 S may be appropriately altered, as long as they match the number of the permanent magnets  33 A,  33 B. 
     The mold resin part  35  is disposed between the plurality of core piece parts  34 N,  34 S. The mold resin part  35  is made of resin. In the present embodiment, the plurality of core pieces  34 N,  34 S are retained in the mold resin part  35 . Except for the lid part  35   d  which will be described in detail later, the mold resin part  35  is a single member. The mold resin part  35  is formed by, for example, a resin molding which involves disposing the core piece parts  34 N,  34 S to a mold, and pouring resin therein. Also, except for the lid part  35   d , all portions of the mold resin part  35  may be formed of a plurality of resins. 
     In the present description, the mold resin part being disposed between the plurality of core pieces refers to the meaning that at least a portion of the mold resin part is located on a line that connects any two core piece parts of the plurality of core piece parts. The two core piece parts of the plurality of core piece parts are not particularly limited, and they may be two circumferentially neighboring core piece parts, or two core piece parts that face each other in the radial direction a cross the shaft  31 . 
     As shown in  FIG. 2 , the mold resin part  35  has, for example, a substantially cylindrical shape. The mold resin part  35  has an outer resin part  35   a , an upper cover part  35   b , a lower cover part  35   c , and a lid part  35   d . Also as shown in  FIG. 4 , the mold resin part  35  has an inner resin part  35   e.    
     The outer resin part  35   a  is disposed at a radially outer side of the permanent magnets  33 A,  33 B. The outer resin part  35   a  is disposed in plurality per every permanent magnet  33 A,  33 B. As shown in  FIG. 5 , in the present embodiment, a portion of the outer resin part  35   a  is disposed on the chamfered portion of the core piece part  34 N. That is, since the core piece corner  34   c  of the core piece part  34 N is chamfered, it is possible to increase the volume of the outer resin part  35   a , and increase the thickness of the outer resin part  35   a , when compared to a case in which the core piece corner  34   c  is not chamfered. Thus, by installing an outer first guide part  36   b  to the outer resin part  35   a , for example, it is easy to make the outer first guide part  36   b  in a stable manner. 
     As shown in  FIG. 4 , the inner resin part  35   e  is a part located at a radially inner side of the permanent magnets  33 A,  33 B and the core piece parts  34 N,  34 S in the rotor  30 . The inner resin part  35   e  is coupled to the outer surface of the shaft  31  in the circumferential direction. As shown in  FIG. 5 , a portion of the inner resin part  35   e  overlaps with the permanent magnet  33 A in the radial direction. 
     According to the present embodiment, a circumferential inner end portion of the core piece part  34 N is disposed at a radially outer side than a circumferential inner end portion of the permanent magnet  33 A. For this reason, it is easy to increase the thickness of a radially overlapping portion of the inner resin part  35   e  and the permanent magnet  33 A. Accordingly, by installing an inner first guide part  36   a , which is to be described in detail later, to a radially overlapping portion of the inner resin part  35   e  and the permanent magnet  33 A, it is easy to make the inner first guide part  36   a  in a stable manner. 
     As shown in  FIG. 2 , the upper cover part  35   b  is disposed at a radially upper side (+Z side) of the core piece parts  34 N,  34 S. The upper cover part  35   b  has, for example, a disc shape. An end portion of the upper side of the outer resin part  35   a  is integrally connected to the upper cover part  35   b . Accordingly, the upper cover part  35   b  connects the plurality of outer resin parts  35   a . Also, the exterior shape of the upper cover part  35   b  may be appropriately altered, as long as it matches the exterior shape of the rotor  30 . 
     The upper cover part  35   b  has at least one cover part through hole  35   f  which penetrates through the upper cover part  35   b  in the axial direction (Z-axis direction). In this embodiment, the cover part through hole  35   f  is provided in plurality along the circumferential direction. The cover part through hole  35   f  overlaps with the magnet insertion hole  38 , which is to be described in detail later, and the permanent magnet  33 A or the permanent magnet  33 B in the axial direction. For this reason, a worker can visually confirm through the cover part through hole  35   f  that the permanent magnets  33 A,  33 B are properly inserted into the magnet insertion hole  38 . As shown in  FIG. 6 , which is to be described in detail later, the opening part area of the cover part through hole  35   f  is smaller than the opening part of the axially upper side of the magnet insertion hole  38 . 
     The lower cover part  35   c  is disposed at an axially lower side (−Z side) of the core piece parts  34 N,  34 S. The lower cover part  35   c  has, for example, a disc shape. An end portion of the lower side of the outer resin part  35   a  is integrally connected to the lower cover part  35   c . Accordingly the lower cover part  35   c  connects the plurality of outer resin parts  35   a . Also, the exterior shape of the lower cover part  35   c  may be appropriately altered as long as it matches the exterior shape of the rotor  30 . Preferably, the shape of the lower cover part  35   c  is identical to the shape of the upper cover part  35   b.    
     As shown in  FIG. 6 , at least one magnet insertion hole  38  is provided to the lower cover part  35   c . The magnet insertion hole  38  is where the permanent magnet  33 A is inserted into. As shown in  FIG. 5 , the magnet insertion hole  38  is disposed between the circumferentially neighboring core piece parts  34 N,  34 S. That is, the magnet insertion hole is provided to a space between the neighboring core piece parts  34 N,  34 S in the circumferential direction. The magnet insertion hole  38  is adjacent to the circumferentially neighboring core piece parts  34 N,  34 S. Further, a portion of the inner surface of the magnet insertion hole  38  is the surface of the core piece parts  34 N,  34 S in the circumferential direction. Also, preferably, the number of the magnet insertion hole  38  is equal to the sum of the number of the permanent magnet  33 A and the number of the permanent magnet  33 B. 
     As shown in  FIG. 6 , the magnet insertion hole  38  extends in the axial direction (Z-axis direction). Specifically, the inner surface which constitutes the magnet insertion hole  38  extends toward the axial direction (Z-axis direction). In the present embodiment, the magnet insertion hole  38  extends from the bottom surface of the lower cover part  35   c  to the bottom surface of the upper cover part  35   b . In other words, the inner surface which constitutes the magnet insertion hole  38  extends from the bottom surface of the lower cover part  35   c  to the bottom part of the upper cover part  35   b . That is, the floor surface of the magnet insertion hole  38  is the bottom surface of the upper cover part  35   b . The cover part through hole  35   f  us provided to the floor surface of the magnet insertion hole  38 . As shown in  FIG. 5 , the shape of the cross section perpendicular to the axial direction of the magnet insertion hole  38  is, for example, quadrangular, which extends to the radial direction. Further, the shape of the magnet insertion hole  38  may be appropriately altered as long as it matches the shape of the permanent magnets  33 A,  33 B. 
     In the present description, the magnet insertion hole includes a gap between the facing surfaces of the neighboring core piece parts. Also in the present description, the magnet insertion hole includes a hole which is formed by extending the gap between the facing surfaces of the neighboring core piece parts in the axial direction. 
     For example, in the example shown in  FIG. 5 , the magnet insertion hole  38  includes the entire gap between a counter driving side surface  34   b  on the counter driving side (−θZ side) of the core piece part  34 N and a driving side surface  34   a  of the driving side (+θZ side) of the core piece part  34 S. Also, the magnet insertion hole  38  includes a hole which is formed by extending the gap between the driving side surface  34   a  and the counter driving side surface  34   b  in the axial direction. 
     Although it is not illustrated in the drawings, the end portion of the upper side (+Z side) of the inner resin part  35   e  shown in  FIG. 4  is integrally connected to the upper cover part  35   b . The end portion of the lower side (−Z side) of the inner resin part  35   e  is integrally connected to the lower cover part  35   c . Accordingly, the inner resin part  35   e  and the outer resin part  35   a  are connected via the upper cover part  35   b  and the lower cover part  35   c.    
     As shown in  FIG. 3 , the lid part  35   d  is attached to the lower side (−Z side) of the lower cover part  35   c . The exterior shape of the lid part  35   d  is substantially identical to the lower cover part  35   c . The lid part  35   d  closes each of the magnet insertion hole  38  at the lower side (−Z side). 
     As shown in  FIG. 5 , the mold resin part  35  has at least one first guide part provided inside the magnet insertion hole  38 . More specifically, the mold resin part  35  has an inner first guide part  36   a , an outer first guide part  36   b , and a second guide part  37 . The inner first guide part  36   a , the outer first guide part  36   b , and the second guide part  37  are provided inside the magnet insertion hole  38 . That is, at least two first guide parts are provided inside the magnet insertion hole  38 . At least one second guide part is provided inside the magnet insertion hole  38 . 
     In the present embodiment, the mold resin part  35  has the inner first guide part  36   a , the outer first guide part  36   b , and the second guide part  37 . For this reason, when the mold resin part  35  is shaped by a resin mold, for example, the inner first guide part  36   a , the outer first guide part  36   b , and the second guide part  37  are formed simultaneously. Thus, it is easy to install the inner first guide part  36   a , the outer first guide part  36   b , and the second guide part  37  to the rotor  30 , and thereby the productivity of the motor  10  is improved. 
     The inner first guide part  36   a  and the outer first guide part  36   b  are disposed at a more driving side (+θZ side) than a center CL 1  between the neighboring core piece parts  34 N,  34 S in the circumferential direction. In the present embodiment, the inner first guide part  36   a  and the outer first guide part  36   b  are disposed closer to the driving side than the center CL 1  in every magnet insertion hole  38 . That is, all inner first guide part  36   a  and all outer first guide part  36   b  are disposed on the same side in the circumferential direction with respect to the center CL 1  in the magnet insertion hole  38 . Meanwhile, all inner first guide parts  36   a  and all outer first guide parts  36   b  do not necessarily need to be disposed on the same side in the circumferential direction with respect to the center CL 1  in the magnet insertion hole  38 . 
     The inner first guide part  36   a  and the outer first guide part  36   b  cover a portion of a surface on the driving side (+θZ side) of the magnet insertion hole  38 . In the present embodiment, the inner first guide part  36   a  and the outer first guide part  36   b  are provided to the surface on the driving side of the magnet insertion hole. 
     The inner first guide part  36   a  is disposed at a radially inner side than the center of the magnet insertion hole  38  in the radial direction. The outer first guide part  36   b  is disposed at a radially outer side than the center of the magnet insertion hole  38  in the radial direction. That is, in the present embodiment, at least one first guide part is provided respectively at a radially inner side than the center of the magnet insertion hole  38  and at a radially outer side than the center of the magnet insertion hole  38  in the radial direction. 
     In the present embodiment, the inner first guide part  36   a  and the outer first guide part  36   b  are in contact with the permanent magnet  33 A. More specifically, the inner first guide part  36   a  is in contact with a surface on the driving side (+θZ side) of the permanent magnet  33 A. The outer first guide part  36   b  is in contact with the chamfered magnet corner part  33 Aa of the permanent magnet  33 A. For this reason, it addition to the attachment by magnetic force, the permanent magnet  33 A is coupled to the core piece part  34 S by the inner first guide part  36   a  and the outer first guide part  36   b . Accordingly, the permanent magnet  33 A is stably retained inside the magnet insertion hole  38 . 
     As shown in  FIG. 6 , the inner first guide part  36   a  is a rib protrudes inside the magnet insertion hole  38 . For this reason, when the inner first guide part  36   a  is in contact with the permanent magnet  33 A as shown in the present embodiment, it is possible to reduce the contact area between the inner first guide part  36   a  and the permanent magnet  33 A. Accordingly, it is possible to inhibit, for example, iron, etc. that is adhered to the plating provided on a surface of the permanent magnet  33 A or to the permanent magnet  33 A from peeling off from the permanent magnet  33 A. Thus, it is also possible to inhibit contamination from occurring inside the magnet insertion hole  38 . 
     As shown in  FIG. 5 , in the present embodiment, the inner first guide part  36   a  protrudes from a surface on the driving side (+θZ side) of the magnet insertion hole  38  toward the counter driving side (−θZ side). The inner first guide part  36   a  is provided to the inner resin part  35   e . That is, the inner first guide part  36   a  is provided to a portion having a relatively greater thickness in the mold resin part  35 . For this reason, it is possible to make the inner first guide part  36   a , which is a rib, in a stable manner. Also, due to such structure, it is possible to enhance the rigidity of the inner first guide part  36   a.    
     The inner first guide part  36   a  is disposed at a radially inner side than a surface on the counter driving side adjacent to the magnet insertion hole  38  of the core piece part  34 N. For this reason, it is easy to install the inner first guide part  36   a , which is a rib, to a portion having a relatively greater thickness in the mold resin part  35 , that is, in the present embodiment, the inner resin part  35   e.    
       FIG. 7  and  FIG. 8  are cross-sectional views of the inner first guide part  36   a , the outer first guide part  36   b , and the second guide part  37 .  FIG. 7  illustrates the inside of the magnet insertion hole  38  shown in  FIG. 5  as viewed from the −X side.  FIG. 8  illustrates the inside of the magnet insertion hole  38  shown in  FIG. 5  as viewed from the −Y side. Illustration of the permanent magnet  33 A is omitted in  FIG. 7  and  FIG. 8 . 
     As shown in  FIG. 7  and  FIG. 8 , the inner first guide part  36   a  extends in the axial direction (Z-axis direction). More specifically, the inner first guide part  36   a  extends from the upper cover part  35   b  to the lower side (−Z side). That is, the inner first guide part  36   a  is connected to the upper cover part  35   b . For this reason, it is possible to enhance the rigidity of the inner first guide part  36   a , which is a rib. 
     As shown in  FIG. 7 , in a perpendicular direction (Y-axis direction) to both a protruding direction of the inner first guide part  36   a  (X-axis direction) and the axial direction (Z-axis direction), the width L 4  of the inner first guide part  36   a  increases toward the upper side (+Z side). For this reason, when the mold resin part  35  and the magnet insertion hole  38  are shaped, for example, by resin molding, it is easy to pull down the mold to the lower side (−Z side). 
     As shown in  FIG. 8 , in a protruding direction of the inner first guide part  36   a  (X-axis direction), the width L 5  of the inner first guide part  36   a  increases toward the upper side (+Z side). For this reason, when the mold resin part  35  and the magnet insertion hole  38  are shaped, for example, by resin molding, it is easy to pull down the mold to the lower side (−Z side). 
     As shown in  FIG. 5 , the shape of the cross section perpendicular to the extending direction of the inner first guide part  36   a  (Z-axis direction) is semicircular. Accordingly, it is easy to make a mold for the mold resin part  35  when compared to a case in which the shape of the cross section of the inner first guide part  36   a  is tapered. Also due to such shape, burrs are unlikely to occur in the inner first guide portion  36   a.    
     When the inner first guide part  36   a  and the permanent magnet  33 A are in contact with each other, the permanent magnet  33 A may be pushed hard against the inner first guide part  36   a . In such case, when the inner first guide part  36   a  has a tapered shape, for example, the contact area between the inner first guide part  36   a  and the permanent magnet  33 A decreases. When the contact area between the inner first guide part  36   a  and the permanent magnet  33 A is too small, the weight per unit area added to the permanent magnet  33 A from the inner first guide part  36   a  increases. Also, a plating layer may be formed on a surface of the permanent magnet  33 A, or iron, etc. may be adhered to thereto. In such case, when the permanent magnet  33 A is inserted, it is possible that the plating or the iron, etc. on the surface of the permanent magnet  33 A may be peeled off from the permanent magnet  33 A by the weight added from the inner first guide part  36   a.    
     According to the present embodiment, the shape of the cross section of the inner first guide part  36   a  is semicircular. For this reason, in case the permanent magnet  33 A is pushed hard against the inner first guide part  36   a , the contacting area between the permanent magnet  33 A and the first guide part  36   a  is easily secured by the elastic deformation of the inner first guide part  36   a . Accordingly, it is possible to inhibit the weight per unit area added to the permanent magnet  33 A from increasing. It is also possible to inhibit the plating provided on a surface of the permanent magnet  33 A and the iron, etc. adhered to the permanent magnet  33 A from being peeled off from the permanent magnet  33 A. This way, it is possible to further inhibit contamination from occurring inside the magnet insertion hole  38 . 
     In the present description, a semicircular shape includes a semielliptical shape, for example. Also in the present description, a semicircular shape includes a half circle along the line passing through the center of a full circle, and the shape of a portion cut along the line shifted from the center of a full circle. 
     Among the corner parts on a radially outer side of the magnet insert hole  38 , the outer first guide part  36   b  is disposed at a corner part on the driving side (+θZ side). Here, in the present embodiment, the magnet corner part  33 Aa of the permanent magnet  33 A is chamfered, as described above. For this reason, the permanent magnet  33 A easily becomes in contact with a surface on a radially outer side of the magnet insert hole  38  while in contact with the outer first guide part  36   b , even when the outer first guide part  36   b  is provided at the corner part of the magnet insertion hole  38  as in the present embodiment. Accordingly, the permanent magnet  33 A is stably retained inside the magnet insertion hole  38 . 
     The outer first guide part  36   b  is disposed at a radially outer side than the counter driving side surface  34   b  of the core piece part  34 N. The outer first guide part  36   b  is provided to the outer resin part  35   a . As shown in  FIG. 6  and  FIG. 7 , the outer first guide part  36   b  has, for example, a substantially triangular prism shape which extends throughout the entire axial direction (Z-axis direction) of the magnet insertion hole  38 . 
     The second guide part  37  is disposed at a more radially inner side than the center of the magnet insertion hole  38  in the radial direction. The second guide part  37  covers a portion of a surface on a radially inner side of the magnet insertion hole  38 . In the present embodiment, the second guide part  37  is provided to the surface on a radially inner side of the magnet insertion hole  38 . 
     According to the present embodiment, with the second guide part  37  provided, the permanent magnet  33 A can positioned closer to the opposite side of the second guide portion  37  in the radial direction inside the magnet insertion hole  38 . For this reason, it becomes easier to match the radial position of the permanent magnets  33 A,  33 B. As a result, the balance of the magnetic flux passing through the rotor  30 , and the balance of the center of weight of the rotor  30  is easily stabilized both in the circumferential direction and the radial direction. 
     In the present embodiment, the second guide part  37  is disposed at a radially inner side than the center of the magnet insertion hole  38  in the radial direction. For this reason, the permanent magnet  33 A is disposed closer to a radially outer side. Accordingly, the permanent magnet  33 A is arranged closer to the stator  40  which is disposed a radially outer side of the rotor  30 . Thus, the magnetic force acting between the permanent magnet  33 A and the stator  40  is increased, and as a result, the rotational torque of the motor  10  is enhanced. 
     In the present embodiment, the second guide part  37  is in contact with the permanent magnet  33 A. More specifically, the second guide part  37  is in contact with a surface on a radially inner side of the permanent magnet  33 A. Accordingly, the permanent magnet  33 A is stably disposed closer to a radially outer side inside the magnet insertion hole  38 . 
     In the present embodiment, the second guide part  37  disposed, for example, at the center of the neighboring core piece parts  34 N,  34 S in the circumferential direction. That is, the center of the second guide part  37  in the circumferential direction overlaps with the center CL 1  between the neighboring core pieces  34 N,  34 S in the circumferential direction. Accordingly, the second guide part  37  is in contact with the vicinity of the center of a surface on a radially inner of the permanent magnet  33 A in the circumferential direction. For this reason, it is easy to stably support the permanent magnets  33 A from a radially inner side within the magnet insertion hole  38 . 
     As shown in  FIG. 6 , the second guide part  37  is a rib protruding inside the magnet insertion hole  38 . As shown in  FIG. 5 , the second guide part  37  protrudes radially outward from a surface on a radially inner side of the magnet insertion hole  38 . The second guide part  37  is provided to the inner resin part  35   e . The second guide part  37  is disposed at a radially inner side than the counter driving side surface  34   b  adjacent to the magnet insertion hole  38  of the core piece part  34 N. 
     As shown in  FIG. 7  and  FIG. 8 , the second guide part  37  extends in the axial direction (Z-axis direction). More specifically, the second guide part  37  extends from the upper cover part  35   b  to the lower side (−Z side). As shown in  FIG. 8 , in a perpendicular direction (X-axis direction) to a protruding direction (Y-axis direction) of the second guide part  37 , the width L 6  of the second guide part  37  increases toward the upper side (+Z side). As shown in  FIG. 7 , in a protruding direction (Y-axis direction) of the second guide part  37 , the width L 7  of the second guide part  37  increases toward the upper side. As shown in  FIG. 5 , the shape of the cross section perpendicular to the extending direction (Z-axis direction) of the second guide part  37  is semicircular. 
     As described above, the second guide part  37  is a rib as the inner first guide part  36   a , and therefore generates the same effect which the inner first guide part  36   a  generates as a rib. 
     As shown in  FIG. 5 , in the present embodiment, L 1  is a distance in the circumferential direction between an end portion on the counter driving side (−θZ side) of the inner first guide part  36   a  and the core piece part  34 S on the counter driving side of the magnet insertion hole  38 . L 2  is the width in the circumferential direction of the permanent magnet  33 A. L 3  is a distance in the circumferential direction between an end portion on the counter driving side of the inner first guide part  36   a  and the core piece part  34 N on the driving side (+θZ side) of the magnet insertion hole  38 . Here, with respect to the distance L 1 , width L 2  and distance L 3 , the motor  10  of the present embodiment satisfies the relationship L 1 −L 2 &lt;L 3 . The relationship is also satisfied when L 3  is a distance in the circumferential direction between an end portion on the counter driving side of the outer first guide part  36   b  and the core piece part  34 N. 
     Accordingly, regardless of the circumferential position of the permanent magnet  33 A, the distance in the circumferential direction between a surface on the counter driving side (−θZ side) of the permanent magnet  33 A and the core piece part  34 S is smaller than the distance in the circumferential direction between a surface on the driving side (+θZ side) of the permanent magnet  33 A and the core piece part  34 N. For this reason, the magnetic force between the core piece part  34 S and the permanent magnet  33 B is bigger than the magnetic force between the core piece  34 N and the permanent magnet  33 A, regardless of the circumferential position of the permanent magnet  33 A. Therefore, the permanent magnet  33 A inserted to the magnet insertion hole  38  is attached to the core piece part  34 S by magnetic force. 
     As described above, according to the present embodiment, it is possible to attach the permanent magnet  33 A by magnetic force to the core piece part  34 S on the side where the inner first guide part  36   a  and the outer first guide part  36   b  are not provided (−θZ side). As a result, it is easy to attach the permanent magnets  33 A,  33 B by magnetic force to the core piece parts  34 N,  34 S disposed on the same circumferential side. Accordingly, it is possible to inhibit the magnetic flux passing through the rotor  30  from scattering, and the balance of the center of gravity of the rotor  30  in the circumferential direction from becoming off-balanced. As a result, it is possible to acquire the motor  10  having a structure to inhibit the vibration and the noise which are caused by the rotation of the rotor  30 . 
     Also as a result, according to the present embodiment, it is possible to employ a method of integrally forming the core piece parts  34 N,  34 S into a single unity by using resin molding, and then disposing the permanent magnets  33 A,  33 B between the core piece parts  34 N,  34 S in the circumferential direction. Accordingly, when the core piece parts are integrally formed by resin molding, the magnetic force of the permanent magnets  33 A,  33 B is prevented from being reduced by the heat generated from the resin. 
     In the present embodiment, the permanent magnet  33 A is in direct contact with the inner first guide part  36   a , the outer first guide part  36   b , and the core piece part  34 S. Accordingly, the distance L 1  and the width L 2  are identical. 
     Also in the present description, the width in the circumferential direction includes a width of an object in a direction perpendicular to both a line which passes through one point in the circumferential direction of the object and the axial direction. For example, the width L 2  in the circumferential direction of the permanent magnet  33 A includes a width of the permanent magnet  33 A in a direction perpendicular to a line which passes through the center of the permanent magnet  33 A in the circumferential direction and also to the axial direction. The same applies to the distance in the circumferential direction. That is, the distance in the circumferential direction includes a distance of the object in a direction perpendicular to a line in the radial direction passing through one point in the circumferential direction of the object and to the axial direction. 
     Since the structure of the present embodiment allows the permanent magnet  33 A to be attached to the intended core piece part  34 N,  34 S by magnetic force, disposing a separate member on the driving side (+θZ side) of the permanent magnet  33 A to add force to the core piece parts can be considered. Here, the separate member may be, for example, a spring. In such structure, when the permanent magnet  33 A is attached to the core piece part  34 N by magnetic force, the permanent magnet  33 A is separated to the core piece part  34 S side by, for example, the elastic force of a spring. However, with such configuration, when the permanent magnet  33 A is pulled away from the core piece part  34 N, there is a possibility that the permanent magnet  33 A may be damaged. Here, the damage refers to, for example, the plating on a surface of the permanent magnet  33 A peeling off, etc. 
     According to the present embodiment, when the permanent magnet  33 A is inserted to the magnet insertion hole  38 , the permanent magnet  33 A is inhibited from adhering to the core piece part  34 N on the unintended side by magnetic force. Therefore, the permanent magnet  33 A is inhibited from being damaged. 
     Also according to the present embodiment, all inner first guide parts  36   a  and all outer first guide parts  36   b  are disposed on the same circumferential side with respect to the center CL 1 . Therefore, all permanent magnets  33 A,  33 B are adhered to the core piece parts  34 N,  34 S on the same circumferential side by magnetic force. Accordingly, the vibration and the noise caused by the rotation of the rotor  30  are further inhibited. 
     According to the present embodiment, there are two types of first guide part, which are the inner first guide part  36   a  and the outer first guide part  36   b . Therefore, the permanent magnet  33 A is inhibited from being inclined in the circumferential direction, and the permanent magnet  33 A is adhered to the first guide part and the core piece part  34 S on the opposite side by magnetic force while keeping a good balance. Also when the first guide part is in contact with the permanent magnet  33 A, the permanent magnet  33 A is retained inside the magnet insertion hole in a more stable manner. 
     According to the present embodiment, the inner first guide part  36   a  is disposed at a radially inner side than the center of the magnet insertion hole  38  in the radial direction. The outer first guide part  36   b  is disposed on a radially outer side than the center of the magnet insertion hole  38  in the radial direction. For this reason, when the rotor  30  is manufactured, it is easy to guide the permanent magnet  33 A to the core piece part  34 S side (−θZ side) in both circumferential directions, while keeping good balance. The permanent magnet  33 A is more securely adhered to the first guide part and the core piece part  34 S on the opposite side by magnetic force. Also when the first guide part is in contact with the permanent magnet  33 A, the permanent magnet  33 A is retained inside the magnet insertion hole  38  in a more stable manner. 
     According to the present embodiment, the shape of the cross section perpendicular to the axial direction of the permanent magnet  33 A is quadrangular. Therefore, the permanent magnet  33 A is retained inside the magnet insertion hole  38  in a more stable manner by the first guide part provided on both sides of the center of the magnet insertion hole  38  in the circumferential direction. 
     Also, the present embodiment may employ the below described configuration. In the below description, the constitutions identical to the foregoing description will be referred to with the same reference numbers, and those constitutions may not be explained in detail. 
     The present embodiment may configure the mold resin part  35  to have at least one first guide part provided inside the magnet insertion hole  38 . That is, only one first guide part may be provided in the mold resin part  35 , or a plurality (for example, three or more) of first guide parts may be provided therein. 
     The present embodiment may configure the permanent magnet  33 A to be in direct contact or in indirect contact via resin with the core piece part  34 S on the counter driving side (−θZ side) of the magnet insertion hole  38 . That is, the permanent magnet  33 A as shown in  FIG. 9  may be in indirect contact with the core piece part  34 S on the other circumferential side of the magnet insertion hole  38  via resin. In the following description, the resin disposed between the permanent magnet  33 A and the core piece part  34 S is referred to as an interposed resin part  135   g.    
       FIG. 9  is a cross-sectional view which illustrates a portion of a rotor  130  according to another example of the present embodiment. As shown in  FIG. 9 , the rotor  130  has a rotor body unit  132 . The rotor body unit  132  has permanent magnets  133 A,  133 B, core piece parts  34 N,  34 S, and a mold resin part  135 . The shape of the permanent magnets  133 A,  133 B is identical to the permanent magnets  33 A,  33 B as shown in  FIG. 5 , except for that the width L 2  in the circumferential direction is a little smaller. 
     The mold resin part  135  has an interposed resin part  135   g . The interposed resin part  135   g  is provided inside the magnet insertion hole  38 . The interposed resin part  135   g  is in contact with a surface on the counter driving side (−θZ side) of the magnet insertion hole  38 . That is, the interposed resin part  135   g  is in contact with the driving side surface  34   a  of the core piece part  34 S. The interposed resin part  135   g  has the shape of a wall which covers the entire surface on the counter driving side of the magnet insertion hole  38 . The interposed resin part  135   g  is in contact with the outer resin part  35   a  and the inner resin part  35   e . Although it is not illustrated in the drawings, the interposed resin part  135   g  is connected to the upper cover part  35   b  and the lower cover part  35   c.    
     With such configuration, the permanent magnet  133 A is in indirect contact with the core piece part  34 S on the counter driving side (−θZ side) of the magnet insertion hole  38  through the interposed resin part  135   g . The relation of L 1 −L 2 &lt;L 3  is also satisfied. Here, the value obtained by subtracting the width L 2  from the distance L 1  corresponds to the width L 8  in the circumferential direction of the interposed resin part  135   g . That is, the width L 8  in the circumferential direction of the interposed resin part  135   g  is smaller than the distance L 3  in the circumferential direction between an end portion on the counter driving side of the inner first guide part  36   a  and the core piece part  34 N on the driving side (+θZ side) of the magnet insertion hole  38 . 
     Accordingly, as shown in the configuration of  FIG. 1  to  FIG. 8 , the permanent magnet  133 A is adhered to the core piece part  34 S on the intended side by magnetic force. Therefore, the vibration and the noise caused by the rotation of the rotor  130  are inhibited. 
     According to this configuration, the permanent magnet  133 A is not in direct contact with the core piece part  34 S. Therefore, for example, when the need to separate the permanent magnet  133 A once from the magnet insertion hole  38  occurs, it is easy to pull the permanent magnet  133 A away from the magnet insertion hole  38 . It is also possible to inhibit a surface of the permanent magnet  133 A from being damaged at that time. 
     The present embodiment may configure the first guide part to cover at least a portion of a surface on the driving side (+θZ side) of the magnet insertion hole  38 . That is, the first guide part as shown in  FIG. 10  may cover the entire surface on the driving side of the magnet insertion hole  38 . 
       FIG. 10  is a cross-sectional view which illustrates a portion of a rotor  230  according to another example of the present embodiment. As shown in  FIG. 10 , the rotor  230  has a rotor body unit  232 . The rotor body unit  232  has permanent magnets  233 A,  233 B, core piece parts  34 N,  34 S, and a mold resin part  235 . The permanent magnets  233 A,  233 B are identical to the permanent magnets  33 A,  33 B shown in  FIG. 5 , etc., except for that each corner part is not chamfered. 
     The mold resin part  235  has a first guide part  236  and a second guide part  37 . The first guide part  236  has the shape of a wall which covers the entire surface on the driving side (+θZ side) of the magnet insertion hole  38 . The first guide part  236  is in contact with the counter driving side surface  34   b  of the core piece part  34 N. The first guide part  236  is in connected to the outer resin part  35   a  and the inner resin part  35   e . Although it is not illustrated in the drawings, the first guide part  236  is connected to the upper cover part  35   b  and the lower cover part  35   c.    
     With such configuration, the entire surface on the driving side (+θZ side) of the permanent magnet  233 A is in contact with the first guide part  236 . Accordingly, the permanent magnet  233 A is retained inside the magnet insertion hole  38  in a more stable manner. 
     The present embodiment may configure the first guide part shown in  FIG. 11  to be disposed apart from a surface on the driving side (+θZ side) of the magnet insertion hole  38 . 
       FIG. 11  is a cross-sectional view which illustrates a portion of a rotor  330  according to another example of the present embodiment. As shown in  FIG. 11 , the rotor  330  has a rotor body unit  332 . The rotor body unit  332  has permanent magnets  333 A,  333 B, core piece parts  34 N,  34 S, and a mold resin part  335 . The shape of the permanent magnets  333 A,  333 B is identical to the permanent magnets  233 A,  233 B shown in  FIG. 10 , except that the width in the circumferential direction is a little smaller. 
     The mold resin part  335  has an inner first guide part  336   a , an outer first guide part  336   b , and a second guide part  37 . The inner first guide part  336   a  and the outer first guide part  336   b  are provided inside the magnet insertion hole  38 . The inner first guide part  336   a  and the outer first guide part  336   b  are disposed at the counter driving side (−θZ side) apart from the driving side (+θZ side) of the magnet insertion hole  38 . 
     The inner first guide part  336   a  protrudes radially inward from a surface on a radially outer side of the magnet insertion hole  38 . The inner first guide part  336   a  is connected to the outer resin part  35   a . The shape of the cross section perpendicular to the axial direction of the inner first guide part  336   a  is, for example, quadrangular. Although it is not illustrated in the drawings, the inner first guide part  336   a  is, for example, provided at a portion in the axial direction (Z-axis direction) of the magnet insertion hole  38 . A surface on the counter driving side (−θZ side) of the inner first guide part  336   a  is in contact with the permanent magnet  333 A. 
     The outer first guide part  336   b  protrudes radially inward from a surface on a radially outer side of the magnet insertion hole  38 . The outer first guide part  336   b  is connected to the inner resin part  35   e . Other constitutions of the outer first guide part  336   b  are identical to those of the inner first guide part  336   a . Also as shown in  FIG. 11 , the outer first guide part  336   b  faces the inner first guide part  336   a  in the radial direction. 
     In the present embodiment, the entire first guide part does not necessarily need to be on the same side as the magnet insertion hole  38 . Also, the first guide part may not be provided to some of the magnet insertion holes  38 . 
     The present embodiment may configure at least a portion of the first guide part to be a rib which protrudes inside the magnet insertion hole  38 . That is, when a plurality of first guide parts is provided, all of them may be a rib. 
     The present embodiment may configure the second guide part  37  to cover as least a portion of a surface on a radially inner side of the magnet insertion hole  38 . That is, the second guide part  37  may cover the entire surface on a radially inner side of the magnet insertion hole  38 . 
     The present embodiment may configure the second guide part  37  to be disposed at one circumferential side relative to the center of the magnet insertion hole  38  in the radial direction, and cover at least a portion of a surface on one radial side of the magnet insertion hole. That is, the second guide part  37  is disposed at a radially outer side than the center of the magnet insertion hole  38  in the radial direction, and may cover at least a portion of a surface on a radially outer side of the magnet insertion hole. 
     The present embodiment may also configure the second guide part  37  to be disposed apart from a surface on a radially inner side of the magnet insertion hole  38 . 
     In the present embodiment, the second guide part  37  may not be provided to some of the magnet insertion hole  38 , and the second guide part  37  may not be provided to any of the magnet insertion hole  38 . 
     Also in the present embodiment, the magnet insertion hole  38  may pass through the rotor  30  in the axial direction (Z-axis direction). 
     In the present embodiment, the rotor body unit  32  may be coupled to the shaft  31  through a separate member. 
     Second Embodiment 
     The second embodiment is different from the first embodiment in that the core piece parts are connected to each other. The constitutions identical to those of the first embodiment will be referred to with the same reference numbers, and those constitutions may not be explained in detail. 
       FIG. 12  is a cross-sectional view of a rotor  430  according to the present embodiment.  FIG. 13  is a partially enlarged view of  FIG. 12 . As shown in  FIG. 12 , the rotor  430  has a shaft  31  and a rotor body unit  432 . The rotor  430  also has a magnet insertion hole  438 . The magnet insertion hole  438  is identical to the magnet insertion hole  38  of the first embodiment. 
     The rotor body unit  432  has a plurality of permanent magnets  33 A,  33 B, a core annular part  434   d , a core piece connector part  434   e , a plurality of core piece parts  434 N,  434 S, and a mold resin part  435 . 
     The core annular part  434   d  is a portion of an annular shape. The core annular part  434   d  is, for example, fixed by being fitted into the outer circumferential surface of the shaft  31 . The core piece connector part  434   e  extends radially outward from the core annular part  434   d . The core piece connector part  434   e  is provided in plurality. The plurality of core piece connector parts  434   e  is for example, provided at equal spaces in the circumferential direction. 
     A radially outer end portion of the core piece connector part  434   e  is connected to the core piece parts  434 N,  434 S, respectively. Accordingly, the core piece parts  434 N,  434 S are connected to each other via the core piece connector part  434   e  and the core annular part  434   d . For this reason, it is possible to improve the relative positional accuracy between the core piece parts  434 N,  434 S. 
     The number of the core piece part  434 N provided in the present embodiment is, for example, four. The number of the core piece part  434 S is also, for example, four. Accordingly, the number of the permanent magnet  33 A provided in the present embodiment is, for example, four. The number of the permanent magnet  33 B is also, for example, four. That is, the number of the core piece part  434 N is identical to the number of the core piece part  434 S, the number of the permanent magnet  33 A, and the number of the permanent magnet  33 B, respectively. Also, the number of these constitutions may be appropriately altered as long as they are capable of constituting the rotor  30 . 
     Other constitutions of the core piece parts  434 N,  434 S are identical to those of the core piece parts  34 N,  34 S of the first embodiment, except for a little difference in their shape. 
     A portion of the mold resin part  435  is disposed between the neighboring core piece connector parts  434   e  in the circumferential direction. A portion of the mold resin part  435  connects the core piece parts  434 N,  434 S, the core piece connector parts  434   e , and the core annular part  434   d . A part of the mold resin part  435  connects the circumferentially neighboring core piece connector parts  434   e  in the circumferential direction. Therefore, it is possible to reinforce the core piece connector part  434   e  by the mold resin portion  435 . As a result, the connection between the core annular part  434   d  and the core piece parts  434 N,  434 S is strengthened. 
     The mold resin part  435  has first guide parts  436   a ,  436   b , and second guide parts  436   b ,  436   c . More specifically, the mold resin part  435  has an inner first guide part  436   a , outer first guide parts  436   b ,  436 , and second guide parts  437   a ,  437   b , as shown in  FIG. 13 . 
     The structure of the inner first guide part  436   a  is identical to the inner first guide part  63   a  of the first embodiment. The structure of the outer first guide part  436   b  is identical to the outer first guide part  36   b  of the first embodiment, except that it is in contact with the permanent magnet  33 A via the outer first guide part  436   c.    
     The outer first guide part  436   c  is provided on a surface which the outer first guide part  436   c  faces the permanent magnet  33 A. The outer first guide part  436   c  is a rib which protrudes inside the magnet insertion hole  438 . The outer first guide part  436   c  is disposed at a radially outer side than a counter driving side surface  434   b  adjacent to the magnet insertion hole  438  of the core piece part  434 N. That is, in the present embodiment, the inner first guide part  436   a  and the outer first guide part  436   c , which are ribs, are disposed at a radially inners side or at a radially outer side than the counter driving side surface  434   b  adjacent to the magnet insertion hole  438  of the core piece part  434 N. As a result, it is easy to install the first guide part, which is a rib, to a portion having a relatively greater thickness in the mold resin part  435 . 
     The outer first guide part  436   c  is in contact with the magnet corner part  33 Aa of the permanent magnet  33 A. The shape of the outer first guide part  436   c , which is a rib, is, for example, identical to the shape of the inner first guide part  36   a  of the first embodiment, which is also a rib. 
     The second guide parts  437   a ,  437   b  is provided inside the magnet insertion hole  438 . That is, at least two second guide parts are provided inside the magnet insertion hole  438 . Accordingly, it is easy to adjust the permanent magnet  33 A closer to a radially outer side. 
     The second guide part  437   a  is disposed closer to the driving side +θZ side) than the center of the magnet insertion hole  438  in the circumferential direction. The second guide part  437   b  is disposed closer to the counter driving side (−θZ side) than the center of the magnet insertion hole  438  in the circumferential direction. That is, in the present embodiment, at least one second guide part is each provided closer to the driving side than the center of the magnet insertion hole  438  in the circumferential direction, and closer to the counter driving side than the center of the magnet insertion hole  438  in the circumferential direction. As a result, the permanent magnet  33 A is retained at a radially inner side in a more stable manner. 
     The second guide parts  437   a ,  437   b  are ribs. Other constitutions of the second guide parts  437   a ,  437   b  are identical to those of the second guide part  37  of the first embodiment. Other constitutions of the rotor  430  are identical to those of the rotor  30  of the first embodiment. 
     The present embodiment may also configure at least one of the second guide parts  437   a ,  437   b  to be a rib which protrudes inside the magnet insertion hole  438 . That is, for example, only one of the second guide parts  437   a ,  437   b  may be a rib. 
     Further, the purpose of the motor according to the present disclosure is not particularly limited. The motor according to the present disclosure is used, for example, as a motor equipped in a vehicle. 
     Each constitution of the first embodiment and the second embodiment described above may be appropriately combined as long as they do not contradict each other. 
     While embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims. 
     While the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof. The accompanying claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention. 
     The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.