Motor

Abstract

To provide an IPM motor (embedded magnet type motor) with excellent magnetic properties of an embedded magnet.SOLUTION: A motor according to the present invention includes a rotating shaft 2, a stator 4, a rotor core 33 having a hole 33h, and a rotor 3 having a magnet 31 and a magnetic body 32 housed in the hole 33h. In a radial direction CD, the magnet 31 and the magnetic body 32 are lined up, and the magnetic body 32 is on the rotating shaft 2 side (inside d) with respect to the magnet 31.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a motor. [Background technology]

[0002] Conventionally, motors using a rotor in which a magnet is embedded in a rotor yoke made of laminated electromagnetic steel sheets (hereinafter, sometimes referred to as "IPM motors") have been known (see, for example, Patent Document 1). In an IPM motor, in order to efficiently realize magnetic interaction with the stator, it is desirable to minimize the air gap between the embedded magnet and the inner wall of the rotor yoke on the stator side.

[0003] In an IPM motor, for example, a rotor is obtained by inserting a magnetized magnet axially into a hole for embedding the magnet (hereinafter referred to as an "embedding hole") provided in a rotor yoke made of a magnetic material and fixing it in place. The embedding hole in the rotor yoke, which is made of laminated electromagnetic steel sheets, has an uneven inner surface that is prone to increasing frictional resistance.

[0004] Therefore, to ensure smooth insertion without damaging the magnet, it is desirable to ensure a clearance between the magnet to be embedded and the embedding hole. Also, taking into account the cumulative tolerances when laminating magnetic steel sheets, the embedding hole tends to have a large clearance from the embedded magnet. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-103747 Summary of the Invention [Problem to be solved by the invention]

[0006] An example of an object of the present invention is to provide an IPM motor in which the embedded magnet has excellent magnetic properties. [Means for solving the problem]

[0007] The above-mentioned problems can be solved by, for example, the following aspect of the present invention. That is, one aspect of the present invention is a rotary shaft; a stator; a rotor having a rotor core with a hole, and a magnet and a magnetic body housed in the hole; Equipped with The magnet and the magnetic body are aligned in the radial direction, The motor has the magnetic body on the rotating shaft side relative to the magnet. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view of a motor according to an embodiment of the present invention; [Figure 2] 5 is a longitudinal cross-sectional view of a motor according to an embodiment of the present invention, which corresponds to the cross-sectional view taken along line AA in FIG. 4. [Figure 3] 3 is a cross-sectional perspective view of a motor according to an embodiment of the present invention, which corresponds to the cross-sectional view taken along line BB in FIG. 2. FIG. [Figure 4] 3 is a cross-sectional view of a motor according to an embodiment of the present invention, which corresponds to the cross-sectional view taken along line BB in FIG. 2. [Figure 5] 5 is a partially enlarged cross-sectional view showing a part of a rotor and a part of a stator of a motor according to an embodiment of the present invention, the cross-sectional view being the same as that of FIG. 4. [Figure 6] 5 is a partially enlarged cross-sectional view of a magnet and a magnetic body in a rotor of a motor according to an embodiment of the present invention, and shows the same cross section as FIG. 4. FIG. [Figure 7] 5 is a partially enlarged cross-sectional view of a rotor core extracted from a motor according to an embodiment of the present invention, the cross-sectional view being of the same cross section as FIG. 4. FIG. [Figure 8] 1 is a perspective view of a motor according to an embodiment of the present invention, in which only a magnet and a magnetic body are extracted. [Figure 9] 1 is a perspective view showing how a magnet and a magnetic body that are bonded together are housed in a space in a rotor in a motor according to an embodiment that is an example of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a motor according to an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a perspective view of a motor 1 according to an embodiment that is one example of the present invention, Fig. 2 is a longitudinal cross-sectional view of the motor 1, Fig. 3 is a cross-sectional perspective view of the motor 1, and Fig. 4 is a transverse cross-sectional view at the same cross section as Fig. 3. Fig. 2 corresponds to the AA cross-sectional view in Fig. 4, and Figs. 3 and 4 correspond to the BB cross-sectional view in Fig. 2.

[0010] In the description of this embodiment, the side in the direction of arrow a is referred to as upper side a, and the side in the direction of arrow b is referred to as lower side b in the direction of axis x, which is the rotation shaft of motor 1. Note that in the description of this embodiment, when we say upper side or lower side, we mean the up-down relationship in the drawing, and do not necessarily coincide with the up-down relationship in the direction of gravity.

[0011] In the description of this embodiment, in the radial direction perpendicular to the axis x, the side away from the axis x (the direction of arrow c) is referred to as the outer side c, and the side toward the axis x (the direction of arrow d) is referred to as the inner side d. Furthermore, in the circumferential direction (hereinafter also referred to as the "circumferential direction ef") centered on the axis x, the clockwise direction is referred to as the clockwise direction e, and the counterclockwise direction is referred to as the counterclockwise direction f.

[0012] As shown in Figures 1 to 4, the motor 1 of this embodiment comprises a shaft 2 which serves as a rotating shaft, a rotor 3 which is fixed to the shaft 2 and rotates together with the shaft 2, a stator 4 which is arranged to surround the rotor 3, and a housing 5 which houses some or all of the components of the motor 1 inside.

[0013] The rotor 3 has a magnet 31 disposed within a rotor core 33 made of a magnetic material. The stator 4 has a coil 42 wound around a stator core 41 made of a magnetic material, and is fixed to a housing 5. The motor 1 in this embodiment is a type of inner rotor brushless motor known as an IPM motor. An IPM motor has the magnet 31 embedded in the rotor 3, and is also known as an embedded magnet motor.

[0014] The housing 5 accommodates some or all of the components of the motor 1, such as the rotor 3 and the stator 4. The housing 5 has a housing main body 51 that supports the stator 4, and a cover 52 that covers an opening at the top of the housing main body 51. The housing main body 51 has an annular bottom portion 51a, a protruding portion 51b that is continuous with the inner periphery of the bottom portion 51a and protrudes cylindrically downward b, and an outer periphery portion 51c that is continuous with the outer periphery of the bottom portion 51a.

[0015] The cover 52 includes an annular flat plate portion 52a, a protruding portion 52b that is continuous with the inner periphery of the flat plate portion 52a and protrudes cylindrically downward b, and an outer periphery portion 52c that is continuous with the outer periphery of the flat plate portion 52a. The annular flat plate portion 52a forms the top surface of the housing 5. The protruding portion 52b of the cover 52 protrudes in the longitudinal direction of the shaft 2 (direction of the axis x) in a direction toward the rotor 3 (toward the downward b).

[0016] The outer peripheral portion 51c of the housing main body 51 and the outer peripheral portion 52c of the cover 52 are fitted together and fixed (fastened) together, and all or part of the motor 1 is housed inside the housing 5, thereby completing the motor 1.

[0017] 1, the flat plate portion 52a of the cover 52 has a circular opening 52e in its center and a pair of openings 52d that surround part of the periphery of the opening 52e. The pair of openings 52 are curved in plan view. Although not shown, an opening is also provided in the bottom portion 51a of the housing main body 51. The openings in the bottom portion 51a, together with the openings 52d, connect the inside and outside of the motor 1, creating an air flow that cools the inside of the motor 1.

[0018] As shown in FIG. 2, the motor 1 is provided with two bearings 61 and 62 that support the shaft 2 rotatably relative to the housing 5. The protruding portion 51b of the housing body 51 protrudes cylindrically toward the lower side b in the direction of the axis x, and one bearing 61 of a plurality of bearings 61, 62 is attached inside the protruding portion 51b. The bearing 61 is fixed inside the protruding portion 51b by press fitting or the like.

[0019] The protruding portion 52b of the cover 52 protrudes cylindrically toward the lower side b in the direction of the axis x, and the other bearing 62 of the multiple bearings 61, 62 is attached inside the protruding portion 52b. The bearing 62 is fixed inside the protruding portion 52b by press fitting or the like.

[0020] In the radial direction (cd direction), the outer diameter and inner diameter of one bearing 61 are approximately the same as the outer diameter and inner diameter of the other bearing 62. Note that although the outer diameter and inner diameter of one bearing 61 are approximately the same as the outer diameter and inner diameter of the other bearing 62, the outer diameter and / or inner diameter of the other bearing 62 may be larger or smaller than the outer diameter and / or inner diameter of the one bearing 61.

[0021] The shaft 2 has two ends 2a and 2b, one end 2b on the housing body 51 side is rotatably supported relative to the housing body 51 by one bearing 61, and the other end 2a on the cover 52 side is rotatably supported by the other bearing 62 at a position closer to the other end 2a.

[0022] Therefore, the shaft 2 is fixed to the housing body 51 via the bearing 61 and to the cover 52 via the bearing 62 so as to be freely rotatable in the circumferential direction ef, and one end 2a of the shaft 2 protrudes from the opening 52e of the cover 52.

[0023] The shaft 2 is fixed to the rotor 3, and when the rotor 3 rotates in the circumferential direction ef due to the electromagnetic interaction between the stator 4 and the rotor 3, the shaft 2 rotates in the circumferential direction ef together with the rotor 3. In the motor 1, the rotational force can be output to the outside from the vicinity of one end 2a of the shaft 2.

[0024] The rotor 3 has a rotor core 33, a magnet 31, and a magnetic body 32. The rotor core 33 is a laminate of multiple magnetic bodies, with the multiple magnetic bodies stacked in the direction of the axis x. The rotor core 33 has an annular inner circumferential portion 33a that forms a hole (hereinafter referred to as a "shaft hole") 34, multiple spokes 33b (20 in this embodiment) that are formed radially from the outer circumferential surface of the inner circumferential portion 33a toward the stator 4, and an annular outer circumferential portion 33c that connects the outer circumferential ends of the multiple spokes 33b. The shaft 2 is inserted into the shaft hole 34.

[0025] A plurality of magnets 31 (20 in this embodiment) are embedded in the outer circumferential portion 33c on the radially outer side c together with magnetic bodies 32. The plurality of magnets 31 are arranged at equal intervals in the circumferential direction ef with their magnetic poles facing both radial sides cd. The magnetic poles of the magnets 31 are arranged in the circumferential direction ef so that the magnetic poles facing the outer side c alternate between north and south poles. The magnets 31 and magnetic bodies 32 and the surrounding structure in this embodiment will be described in detail later.

[0026] The stator 4 has an insulator 45, a stator core (magnetic material) 41, and a coil 42. The stator core 41 is a laminate of magnetic material such as silicon steel plates. The stator core 41 has an annular portion (hereinafter referred to as the "annular portion") 41a arranged coaxially with the shaft 2, and a plurality of (24 in this embodiment) magnetic pole portions (also referred to as "teeth") 41b formed to extend from the annular portion 41a toward the shaft 2 (the direction of arrow d).

[0027] The magnetic pole portions 41b can be separated from the annular portion 41a. That is, the stator core 41 is a divided core made up of the annular portion 41a and the magnetic pole portions 41b. The annular portion 41a and the magnetic pole portions 41b are separated by a boundary line R.

[0028] The inner end of the magnetic pole portion 41b at point d forms a protruding portion 41c that protrudes on both sides in the circumferential direction ef. In the radial direction cd, the protruding portion 41c of the stator core 41 and the rotor protruding portion 33d of the rotor core 33 face each other with a magnetic gap G interposed therebetween.

[0029] The coils 42 are wound around each of the magnetic pole portions 41 b. An insulator 45 made of an insulating material is interposed between the stator core 41 and the coils 42, and the stator core 41 and the coils 42 are insulated from each other by the insulator 45.

[0030] Fig. 5 shows a partially enlarged cross-sectional view of the rotor 3 and stator 4 of the motor 1 according to this embodiment. Fig. 6 shows a partially enlarged cross-sectional view of the magnet 31 and magnetic body 32 of the rotor 3 of the motor 1 according to this embodiment, as well as their surroundings, which is even more enlarged than Fig. 5. Fig. 7 shows a partially enlarged cross-sectional view of only the rotor core 33 extracted from the motor 1 according to this embodiment. Figs. 5, 6, and 7 are cross-sectional views of the same cross section as Fig. 4. Note that the coil 42 of the stator 4 is not shown in Fig. 5.

[0031] As shown in FIGS. 5 to 7, the outer peripheral portion 33c of the rotor core 33 has a plurality of protruding portions (hereinafter, the protruding portions will be referred to as "rotor protruding portions") 33d extending toward the stator 4 in the radial direction cd. The plurality of rotor protruding portions 33d has a frame 33f surrounding each of the plurality of magnets 31. In other words, the rotor core 33 has the plurality of protruding portions 33d as its outer peripheral portion, and a predetermined gap is formed between two adjacent protruding portions 33d among the plurality of protruding portions 33d. The formation of this gap forms a plurality of recessed portions on the outer peripheral portion of the rotor core 33. Below, the configuration of the rotor 33 will be described in which the outer peripheral portion 33c of the rotor core 33 has the plurality of protruding portions 33d.

[0032] The frame 33f of the rotor protrusion 33d is formed thin, and a rectangular space 33hc with its longitudinal direction aligned with the axis x is formed inside the frame 33f. In addition, recesses (hereinafter referred to as "rotor recesses") 33e recessed radially inward toward the center d are formed in the outer peripheral portion 33c. These rotor recesses 33e are formed at positions corresponding to the spaces 33hc of the rotor protrusion 33d. A rectangular space 33hd with its longitudinal direction aligned with the axis x is formed inside the rotor recess 33e.

[0033] In the radial direction cd, the rotor 33 has a foot 33j that extends from a step 33k, which is the boundary between the rotor protrusion 33d and the rotor recess 33hd, toward the outer side c. The foot 33j branches into two at its middle. The two branches of the branched foot 33j are connected to the frames 33f of the two rotor protrusions 33d that are adjacent in the circumferential direction ef. The foot 33j has a side surface facing the space 33hc near the branch point from the foot 33j to the two frames 33f, and a pair of protrusions 33g is formed on the side surface of the foot 33j. The pair of protrusions 33g extends in the circumferential direction ef.

[0034] In the circumferential direction ef, the length of the space 33hc is larger than the length of the space 33hd. These spaces 33hc and 33hd are combined to form a hole 33h with the axial direction x as the longitudinal direction (for the above, refer to FIG. 7 in particular). The rotor core 33 includes a plurality of holes 33h, and these plurality of holes 33h are arranged in the circumferential direction ef.

[0035] A magnet 31 and a magnetic body 32 having a rectangular parallelepiped shape with the axial direction x as the longitudinal direction are accommodated in the hole 33h, and the magnet 31 and the magnetic body 32 are embedded in the rotor core 33. At this time, in the radial direction cd, the magnet 31 and the magnetic body 32 are arranged side by side, and the magnetic body 32 is on the side of the rotation axis 2 (equal to the inner side d) with respect to the magnet 31.

[0036] FIG. 8 is a perspective view showing only the magnet 31 and the magnetic body 32 accommodated in the hole 33h of the rotor core 33. As shown in FIG. 8, the magnet 31 and the magnetic body 32 are in a state where one surface including the longitudinal direction (surfaces 31d of the magnet 31 and 32c of the magnetic body 32) are bonded together.

[0037] As shown in FIG. 8, the magnet 31 and the magnetic body 32 have the same length H in the longitudinal direction (equal to the axial direction x). Also, the length (width) in the short side direction (substantially equal to the circumferential direction ef) of the surfaces 31d and 32c where the magnet 31 and the magnetic body 32 are bonded together is shorter for the magnetic body 32 (W2) than for the magnet 31 (W1) (W1>W2). Further, the length (thickness) in the bonding direction (equal to the radial direction cd) of the magnet 31 and the magnetic body 32 is slightly longer for the magnetic body 32 (D2) than for the magnet 31 (D1) (D1<D2). These relationships of the lengths are merely examples and are not limited to the relationships of this embodiment.

[0038] The magnet 31 does not need to be magnetized before it is attached to the magnetic body 32. To fix the unmagnetized magnet 31 to the magnetic body 32, it may be fixed with an adhesive. That is, the magnet 31 may be magnetized after the surface 31d of the magnet 31 and the surface 32c of the magnetic body 32 are attached and fixed together.

[0039] At this time, surface 31d of magnet 31, which is attached to magnetic body 32, and surface 31c opposite surface 31d in the radial direction, are magnetized to have either an N pole or an S pole (hereinafter, "surface 31c" and "surface 31d" may be referred to as "magnetic pole surface 31c" and "magnetic pole surface 31d", respectively). By using magnet 31 that is not magnetized before being attached, it becomes easier to align magnet 31 with magnetic body 32.

[0040] The magnet 31 may be magnetized before being attached to the magnetic body 32. By using a pre-magnetized magnet 31, it is not necessary to use an adhesive to fix the magnetic pole surface 31d of the magnet 31 to the surface 32c of the magnetic body 32. Of course, when a pre-magnetized magnet 31 is used, an adhesive may be used to fix the magnetic pole surface 31d of the magnet 31 to the surface 32c of the magnetic body 32.

[0041] The magnetic body 32 is formed of the same material as the rotor core 33 or a magnetic body containing the same material. Like the rotor core 33, the magnetic body 32 is a laminate of multiple magnetic bodies, with multiple magnetic bodies stacked in the direction of the axis x. In this embodiment, the magnetic body 32 is made of the same material and has the same configuration as the rotor core 33, but some or all of the materials or components may be different as necessary.

[0042] 9 is a perspective view showing how the bonded magnet 31 and magnetic body 32 are accommodated in the hole 33h of the rotor core 33. As shown in FIG. 9, one end in the longitudinal direction of the bonded magnet 31 and magnetic body 32 is moved in the direction of arrow J to insert them into the hole 33h of the rotor core 33.

[0043] When inserting the magnet 31 and the magnetic body 32 into the hole 33h of the rotor core 33, it is preferable to press them toward the radially outward direction c so that the magnetic pole surface 31c of the magnet 31 is adhered to the inner surface 33fc of the hole 33h. Alternatively, after inserting the magnet 31 and the magnetic body 32 into the hole 33h, a stick-shaped or wedge-shaped member may be press-fitted between the surface 32d of the magnetic body 32 and the inner surface 33ed of the hole 33h of the rotor core 33, so that the magnetic pole surface 31c of the magnet 31 is adhered to the inner surface 33ed of the hole 33h.

[0044] The rotor 3 of this embodiment is obtained by performing the above operation for all the holes 33h. At this time, the orientations of the magnetic poles (N poles, S poles) of the magnets 31 adjacent to each other in the circumferential direction ef are made different.

[0045] The magnet 31 housed in the hole 33h has one magnetic pole face 31d attached to the magnetic body 32, and the other magnetic pole face 31c facing outward c. That is, the magnetic force from the other magnetic pole face 31c facing outward c acts directly on the inner surface 33fc of the hole 33h of the rotor core 33. In contrast, the magnetic force from the one magnetic pole face 31d of the magnet 31 facing inward d acts on the inner surface 33ed of the hole 33h of the rotor core 33 via the attached magnetic body 32.

[0046] That is, the attractive force acting between pole face 31c of magnet 31 and inner face 33fc of hole 33h of rotor core 33 is greater than the attractive force acting between face 32d of magnetic body 32 and inner face 33ed of hole 33h of rotor core 33. Therefore, pole face 31c of magnet 31 and inner face 33fc of hole 33h of rotor core 33 are attracted to each other by magnetic force and are stably fixed together.

[0047] Therefore, according to this embodiment, the magnetic pole surface 31c of the magnet 31 is attracted to the inner surface 33fc of the hole 33h of the rotor core 33 by magnetic force, so that an air gap is unlikely to occur between the magnetic pole surface 31c and the inner surface 33fc.

[0048] As described above, in the rotor 3 of this embodiment, the magnetic pole face 31c of the magnet 31 is in contact with the inner surface 33fc of the hole 33h that faces it. Therefore, in the magnet 31, the magnetic pole face 31c that faces the stator 4 is kept at a constant distance from the stator 4, which makes it possible to suppress a decrease in magnetic properties. Furthermore, no air gap is created between the magnetic pole face 31c of the magnet 31 and the inner surface 33fc of the hole 33h, and the magnetic flux of the magnet 31 flows from the inner surface 33fc to the frame 33f, maintaining a good state, thereby suppressing a decrease in the amount of magnetic flux.

[0049] In the rotor 3 of this embodiment, the position of the magnet 31 in the circumferential direction ef is restricted by a pair of protrusions 33g formed in the hole 33h. That is, the pair of protrusions 33g contact the side surfaces 31e, 31f of the magnet 31 in the circumferential direction ef to fix the magnet 31. Therefore, the side surfaces 33he, 33hf in the space 33hc of the hole 33h are separated by a predetermined distance from the both side surfaces 31e, 31f of the magnet 31. Therefore, there is a gap between the side surfaces 33he, 33hf of the hole 33h and the side surfaces 31e, 31f of the magnet 31 in the circumferential direction ef.

[0050] When the side surfaces 31e and 31f of the magnet 31 contact the rotor core 33, which is a magnetic body, leakage of magnetic flux occurs from this contact area. The magnetic flux from the side surfaces 31e and 31f of the magnet 31 flows to the magnetic body 32 (magnetic flux leakage), which may reduce the magnetic efficiency.

[0051] However, in this embodiment, there is a gap between the side surfaces 33he, 33hf of the hole 33h and the side surfaces 31e, 31f of the magnet 31 in the circumferential direction ef, which prevents magnetic flux from flowing from the side surfaces 31e, 31f of the magnet to the magnetic body 32. The length of the pair of protrusions 33g in contact with the side surfaces 31e, 31f of the magnet 31 is shorter than the side surfaces 31e, 31f of the magnet 31, which reduces leakage of magnetic flux. Furthermore, the pair of protrusions 33g are spaced apart from the pole surface 31c of the magnet 31 that faces the outside c, which reduces the effect of magnetic flux leaking from the pair of protrusions 33g on the magnetic flux density in the magnetic gap G between the rotor protrusions 33d and the stator 41.

[0052] Furthermore, if a corner of the magnet 31 comes into contact with a corner of the hole 33h in the circumferential direction, magnetic flux may flow from the corner of the magnet 31 to the corner of the hole 33h, affecting the magnetic flux density in the magnetic gap G. This reduces the magnetic efficiency.

[0053] However, in this embodiment, there is a gap between the side surfaces 31e and 31f of the magnet 31 in the circumferential direction, and some of the corners of the magnetic pole surfaces 31c and 31d, which become the magnetic poles, are separated from some of the corners of the hole portion 33h, thereby suppressing a decrease in magnetic efficiency.

[0054] In this embodiment, the surface 32d of the magnetic body 32 on the side of the rotation shaft 2 (same as the inner surface d) is separated by a predetermined distance from the inner surface 33ed on the side of the rotation shaft 2 (inner surface d) of the hole 33h. This prevents the magnetic flux of the magnet 31 from flowing through the inner surface 33ed to the inner surface 32d of the magnetic body 32, thereby preventing a decrease in magnetic efficiency. Furthermore, as the rotor 3 rotates, centrifugal force acts on the magnet 31 and the magnetic body 32, but the magnet 31 and the magnetic body 32 are stably fixed to the rotor 3 by the rotor protrusion 33d. This prevents a decrease in magnetic efficiency and ensures the physical stability of the magnet 31 and the magnetic body 32.

[0055] The inventors created a comparative motor in which an air gap of 0.2 mm was forcibly set between the magnetic pole surface 31c of the magnet 31 and the inner surface 33fc of the opposing hole 33h, and conducted an experiment to measure the back electromotive force (BEMF) of this comparative motor and the motor 1 of this embodiment.

[0056] As a result, when the back electromotive force (BEMF) of the comparative motor was set to 100, the back electromotive force (BEMF) of motor 1 of this embodiment was 110. When the comparative motor is a conventional motor, an improvement in the back electromotive force (BEMF) of approximately 10% was confirmed for the motor of this embodiment. Since it is actually observed that the air gap in conventional motors is larger than 0.2 mm, the motor 1 of this embodiment is expected to have an even greater improvement in the back electromotive force (BEMF).

[0057] Although the motor of the present invention has been described above using preferred embodiments, the motor of the present invention is not limited to the configuration of the above embodiments. For example, the above embodiments have been described using motors with specific configurations using specific numbers of poles and slots, but the present invention is not limited to these. In the present invention, the number of poles and the number of slots can be selected as appropriate. Furthermore, there are no particular limitations on the configuration of other motors, and the present invention can be applied to any so-called IPM motor.

[0058] In addition, those skilled in the art can appropriately modify the motor of the present invention in accordance with conventionally known knowledge. As long as such modifications still comprise the configuration of the present invention, they are of course included in the scope of the present invention. [Explanation of symbols]

[0059] 1...motor, 2...shaft, 3...rotor, 4...stator, 5...housing, 31...magnet, 31c, 31d...surface (pole surface), 31e, 31f...side surface, 32...magnetic material, 33...rotor core, 33a...inner circumference, 33b...spokes, 33c...outer circumference, 33d...rotor protrusion, 33e...rotor recess, 33f...frame, 33fc...inner surface, 33g...protrusion, 33h...hole, 33hc, 33h d...space, 33he, 33hf...side surface, 33j...foot portion, 33k...step portion, 34...shaft hole, 41...stator core, 41a...annular portion, 41b...magnetic pole portion, 41c...protrusion portion, 42...coil, 45...insulator, 51...housing body, 51a...bottom, 51b...protrusion portion, 51c...outer periphery, 52...cover, 52a...flat plate portion, 52b...protrusion portion, 52c...outer periphery 61, 62...bearing

Claims

1. A rotation axis; a stator; a rotor having a rotor core with a hole, and a magnet and a magnetic body housed in the hole; Equipped with The magnet and the magnetic body are aligned in the radial direction, the magnetic body is located on the rotation shaft side relative to the magnet, the rotor core includes a pair of protrusions formed on side surfaces of the hole, The pair of protrusions contact the side surfaces of the magnet in the circumferential direction, The magnet is disposed between the pair of protrusions in the circumferential direction, In the circumferential direction, there is a gap between a side surface of the hole and a part of a corner portion of the magnet on the magnetic body side, A motor in which a surface of the magnetic body on the rotating shaft side and an inner surface of the hole on the rotating shaft side are spaced apart in the radial direction.

2. The motor according to claim 1 , wherein the magnet is in contact with an inner surface of the hole on the stator side in the radial direction.

3. the rotor core includes a plurality of the holes, The motor according to claim 1 or 2, wherein the plurality of holes are aligned in a circumferential direction.

4. The motor according to claim 1 , wherein a surface of the magnetic body on the side of the rotary shaft is connected to an inner surface of the hole on the side of the rotary shaft.

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