motor

Abstract

To provide a motor that can improve motor efficiency while ensuring strength of an iron core.SOLUTION: A stator core 37 of a motor 1 comprises an annulus part 31, and multiple protrusions 32 that radially extend from the annulus part 31. An inner magnetic body 92 forming the inside of the multiple protrusions 32 is different from an outer magnetic body 91 forming an outer periphery surrounding the inside of the multiple protrusions 32. While members forming the inside of the multiple protrusions 32 are the multiple inner magnetic bodies 92 stacked in an axial direction of the motor 1, members forming the outer periphery surrounding the inside of the multiple protrusions 32 are the multiple outer magnetic bodies 91 stacked in the axial direction. In the axial direction, a thickness of each of the multiple inner magnetic bodies 92 is thinner than a thickness of each of the multiple outer magnetic bodies 91.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] Conventionally, there has been known a motor including a stator having an iron core formed of a plurality of stacked electromagnetic steel sheets and a coil wound around a plurality of teeth of the iron core (see, for example, Patent Document 1). [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2010-207028 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] In recent years, there are cases where improvement in motor efficiency and securing of iron core strength are required for motors such as the motor described in Patent Document 1 and other motors.

[0005] Accordingly, an object of the present invention is to provide a motor capable of improving motor efficiency while securing the strength of the iron core. [Means for Solving the Problem]

[0006] The present invention is a motor including an iron core, wherein the iron core includes an inner circumferential portion and a plurality of protruding portions extending radially from the inner circumferential portion, a member forming the inside of the plurality of protruding portions is different from a member forming an outer circumferential portion surrounding the inside of the plurality of protruding portions, the member forming the inside of the plurality of protruding portions is a plurality of first magnetic bodies stacked in an axial direction of the motor, the member forming the outer circumferential portion surrounding the inside of the plurality of protruding portions is a plurality of second magnetic bodies stacked in the axial direction, and in the axial direction, a thickness of each of the plurality of first magnetic bodies is smaller than a thickness of each of the plurality of second magnetic bodies.

[0007] The above motor may further comprise at least one of the following configurations.

[0008] In other words, the number of stacked layers of the plurality of first magnetic materials may be greater than the number of stacked layers of the plurality of second magnetic materials. Also, the entire outer periphery of the plurality of first magnetic materials may be covered by the plurality of second magnetic materials. Furthermore, the motor may further include an insulator, and the plurality of first magnetic materials may be housed in the plurality of second magnetic materials and the insulator. Alternatively, the iron core may be coated with an insulating paint, and the entire outer periphery of the plurality of first magnetic materials may be covered by the plurality of second magnetic materials and the insulating paint. Also, the protrusion may include teeth and a yoke, and at least a portion of the plurality of first magnetic materials may extend over the entire teeth. Alternatively, the protrusion may include teeth and a yoke, and in the radial direction of the motor, the length of at least a portion of the plurality of first magnetic materials may be shorter than the length of the teeth. Furthermore, the plurality of first magnetic materials may include first magnetic materials of different thicknesses. In this case, the first magnetic materials of different thicknesses may be randomly arranged in the axial direction. Alternatively, the thickness of the first magnetic material located towards the end in the axial direction may be greater than the thickness of the first magnetic material located towards the inside. Also, the materials of the plurality of first magnetic materials and the plurality of second magnetic materials may be different. [Effects of the Invention]

[0009] According to the present invention, a motor is provided in which the strength of the iron core is ensured while the motor efficiency can be improved. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view showing an example of a motor in an embodiment of the present invention. [Figure 2] This is a cross-sectional view of the motor in the direction of its rotation axis, as shown in Figure 1. [Figure 3]Figure 1 is a perspective view showing the iron core and insulator of the motor. [Figure 4] Figure 3 is a perspective view showing the iron core with the insulator removed. [Figure 5] Figure 4 is a cross-sectional view of the iron core in the direction of the axis of rotation. [Figure 6] This figure shows an enlarged view of one end of the iron core and its vicinity in the direction of the axis of rotation shown in Figure 5. [Figure 7] Figure 4 is a radial cross-sectional view of the motor core shown. [Figure 8] This is a cross-sectional view in the direction of the rotation axis showing a part of the iron core according to a first modified embodiment of the present invention. [Figure 9] This is a cross-sectional view in the direction of the rotation axis showing one end of the core in the direction of the rotation axis and its vicinity, according to a second modified embodiment of the present invention. [Figure 10] This is a radial cross-sectional view showing a part of the iron core according to a third modified embodiment of the present invention. [Figure 11] This is a radial cross-sectional view showing a part of the iron core according to a fourth modified embodiment of the present invention. [Figure 12] This is a radial cross-sectional view showing a part of the core according to a fifth modified embodiment of the present invention. [Figure 13] This is a radial cross-sectional view showing a part of the iron core according to a sixth modified embodiment of the present invention. [Figure 14] This is a radial cross-sectional view showing an iron core according to a seventh modified embodiment of the present invention. [Modes for carrying out the invention]

[0011] Hereinafter, modes for carrying out the motor according to the present invention will be exemplified with the accompanying drawings. The embodiments illustrated below are intended to facilitate understanding of the present invention, and are not intended to limit or interpret the present invention. The present invention can be changed or improved from the following embodiments without departing from the gist thereof. In addition, in the above-mentioned accompanying drawings, for ease of understanding, dimensions of each member may be exaggerated or reduced, or hatching may be omitted.

[0012] FIG. 1 is a perspective view showing an example of the motor 1 according to the embodiment, and is a perspective view viewed from one side in the direction of the rotating shaft of the motor 1. Hereinafter, the direction of the rotating shaft of the motor 1 is referred to as "axial direction". FIG. 2 is a cross-sectional view of the motor 1 in the axial direction. In the present embodiment, the motor 1 is configured as a so-called outer-rotor brushless motor.

[0013] As shown in FIG. 1 and FIG. 2, the motor 1 mainly includes a housing 10, a shaft 20, a bearing 21, a bearing 22, a stator 30, a rotor 40, and a cover 50. The shaft 20 has one end 20a and the other end 20b. That is, FIG. 1 is a view viewed from the one end 20a side of the shaft 20.

[0014] The housing 10 includes a base 12 that forms a bottom portion of the housing 10, and a frame 11 that forms a side surface and a top surface of the housing 10. The base 12 is arranged on the other axial side (the other end 20b side of the shaft 20).

[0015] The base 12 is a disk-shaped member, and is disposed perpendicular to the longitudinal direction (axial direction) of the shaft 20 (that is, extends in the radial direction of the motor 1). A cylindrical cylindrical portion 13 extending along the axial direction is formed integrally with the base 12 at the center of the base 12. Further, in the cylindrical portion 13, a hole through which the shaft 20 passes is formed closer to the shaft 20 than the inner peripheral surface 13a of the cylindrical portion 13. In the axial direction of the base 12, electronic components such as capacitors and resistance elements are mounted on a surface on one end 20a side of the shaft 20, and a substrate 15 having wiring and terminals (hereinafter referred to as a circuit board) is placed thereon. In addition, the one end 20a side (one side in the axial direction) of the shaft 20 may be described as "upper", "upper side", "above" or the like, and the other end 20b side (the other side in the axial direction) of the shaft 20 may be described as "lower", "lower side", "below" or the like. A recess 12a is formed in a part of the base 12, and the recess 12a provides the base 12 with an opening. A connector 16 electrically connected to an external device is disposed in the opening. Electric current is externally supplied to a coil 33, which will be described later, of the stator 30 via the connector 16, the circuit board 15, and connection terminals provided on the stator 30.

[0016] The frame 11 includes a cylindrical first cylindrical portion (hereinafter referred to as a large-diameter cylinder) 11A, a disk-shaped top surface portion (hereinafter referred to as a disk portion) 11B, and a cylindrical second cylindrical portion (hereinafter referred to as a small-diameter cylinder) 11C having an outer shape smaller than that of the large-diameter cylinder 11A. The large-diameter cylinder 11A is fixed to an outer peripheral portion of the base 12, and generally extends upward from the position of the base 12 in the axial direction. The disk portion 11B extends in the radial direction, and extends from an upper end of the large-diameter cylinder 11A toward the shaft 20. The term "inner" in the radial direction corresponds to the side facing the shaft 20 from the large-diameter cylinder 11A, and the term "outer" in the radial direction corresponds to the side facing the large-diameter cylinder 11A from the shaft 20. The small-diameter cylinder 11C extends upward from an inner peripheral portion 11B1 of the disk portion 11B. A through hole 11C2 is formed inside an inner peripheral surface 11C1 of the small-diameter cylinder 11C. In the present embodiment, the large-diameter cylinder 11A, the disk portion 11B, and the small-diameter cylinder 11C are integrally formed.

[0017] The housing 10, which has this configuration, houses the shaft 20, bearings 21 and 22, stator 30, rotor 40, and the like.

[0018] Bearing 21 is positioned inside the small-diameter cylinder 11C, and its outer circumferential surface 21a is fixed to the inner circumferential surface 11C1 of the small-diameter cylinder 11C. Bearing 22 is positioned inside the inner circumferential surface 13a of the cylindrical portion 13, and its outer circumferential surface is fixed to the inner circumferential surface 13a of the cylindrical portion 13. Examples of bearings 21 and 22 include ball bearings and sleeve bearings. A stepped portion 13b is formed on the inner circumferential surface 13a of the cylindrical portion 13. In the axial direction, bearing 22 is supported on this stepped portion 13b. The outer circumferential surface of the shaft 20 is supported by the inner circumferential surface of bearing 21 and the inner circumferential surface of bearing 22. In this way, bearings 21 and 22 rotatably support the shaft 20. One end 20a (upper end) of the shaft 20 protrudes above the lid 50, which will be described later, and the other end 20b (lower end) of the shaft 20 is located inside the cylindrical portion 13.

[0019] The cover 50 covers the bearing 21 and the small diameter cylinder 11C. The cover 50 has a first member 56 and a second member 53.

[0020] The first member 56 is an annular member when viewed from above, specifically an annular shape. The annular first member 56 has an inner circumferential surface, and a through hole is formed on the inside of this inner circumferential surface. The shaft 20 passes through this through hole, and the outer circumferential surface of the shaft 20 is fixed to the inner circumferential surface of the first member 56.

[0021] The second member 53 is a cylindrical member, and in this embodiment, it is cylindrical in shape. The second member 53, being a cylindrical member, has a sleeve 51 and a wall portion 52. In this embodiment, the sleeve 51 and the wall portion 52 are integrally formed. The sleeve 51 extends upward from the surface of the disc portion 11B of the frame 11, and the upper surface of the sleeve 51 is approximately flush with the upper surface of the first member 56. The inner circumferential surface of the lower part of the sleeve 51 is fixed to the outer circumferential surface of the small diameter cylinder 11C. On the other hand, the inner circumferential surface of the upper part of the sleeve 51 faces the outer circumferential portion of the first member 56 in the radial direction. Also, there is a gap between the outer circumferential portion of the first member 56 and the inner circumferential surface of the sleeve 51 in the radial direction. Therefore, the first member 56 can rotate together with the shaft 20 relative to the second member 53.

[0022] The wall portion 52 is located near the center (intermediate portion) of the sleeve 51 in the axial direction and extends radially from the cylinder 11C toward the shaft 20 (inward). In the axial direction, the wall portion 52 faces the first member 56 via a washer 70. The washer 70 may be rotatable relative to the shaft 20. The wall portion 52 has a ring-shaped planar form. The wall portion 52 has an inner circumferential surface, and a through hole is formed on the inside of this inner circumferential surface. The shaft 20 passes through this through hole in the wall portion 52. The inner circumferential surface of the wall portion 52 faces the outer circumferential surface of the shaft 20. Also, in the radial direction, there is a gap between the inner circumferential surface of the wall portion 52 and the outer circumferential surface of the shaft 20. Therefore, the shaft 20 can rotate relative to the second member 53.

[0023] The rotor 40 includes a holder 41 and a magnet 44. The holder 41 is made of a magnetic material and has a cylindrical section 43 and an annular section 42 extending inward from the upper end of the cylindrical section 43. The annular section 42 is integrally formed with the cylindrical section 43. The annular section 42 is annular when viewed from above and has an inner circumference 42a. The shaft 20 passes through the inner circumference 42a of the annular section 42 and is fixed to the inner surface of this inner circumference 42a. Therefore, the holder 41 and the shaft 20 rotate integrally. In the radial direction, a spacer 71, a ring 72, and a second ring 73 having a smaller outer shape (or outer diameter) than the spacer 71 and ring 72 are arranged between the inner circumference 42a of the annular section 42 and the shaft 20. The cylindrical section 43 extends downward from the outer circumference 42b of the annular section 42. In the axial direction, the lower end of the cylindrical portion 43 is located below the lower end of the stator core 37 of the stator 30, which will be described later. The magnet 44 has an annular shape and is fixed to almost the entire inner surface of the cylindrical portion 43. The lower end of the magnet 44 is located below the lower end of the cylindrical portion 43. In addition, multiple different magnetic poles (N poles and S poles) are alternately formed along the circumferential direction of this magnet 44. In the radial direction, the magnet 44 faces the stator core 37 of the stator 30 via an air gap G.

[0024] Next, we will describe the stator 30 of motor 1 in detail.

[0025] The stator 30 is fixed to the housing 10 and, as shown in Figure 2, includes a stator core 37 (iron core), an insulator 34 made of an insulating material such as resin, and a plurality of coils 33. Figure 3 is a perspective view showing the stator core 37 and the insulator 34, with the plurality of coils 33 removed. As shown in Figure 3, the insulator 34 surrounds most of the stator core 37.

[0026] Figure 4 is a perspective view showing only the stator core 37 of the stator 30, with the coils 33 and insulators 34 removed. As shown in Figure 4, the stator core 37 includes an annular portion (core) 31 as the innermost inner circumference in the radial direction, and a plurality of protrusions 32 extending radially from the annular portion 31. The annular portion 31 is formed in a cylindrical shape (cylindrical in this embodiment) and has a cylindrical inner circumference 31a. Inside the inner circumference 31a is a through hole that penetrates the stator core 37 in the axial direction. As shown in Figure 2, the upper part of the aforementioned cylindrical portion 13 is fitted into this through hole, and the lower half of the inner circumference 31a of the annular portion 31 is fixed and supported by the upper part of the outer circumference 13e of the cylindrical portion 13. The shaft 20 also passes through the center of this through hole.

[0027] As shown in Figure 4, each of the multiple protrusions 32 of the stator core 37 is formed to the same shape and dimensions and is arranged at approximately equal intervals in the circumferential direction of the annular portion 31. Each of the multiple protrusions 32 includes teeth 80 extending radially outward from the annular portion 31 and a yoke 81 connected to the outer end of the teeth 80. When viewed from the axial direction, the teeth 80 have a rectangular shape. When viewed from the axial direction, the yoke 81 is formed such that its circumferential length increases (i.e., its diameter increases) towards the outside, starting from the connection point with the outer end of the teeth 80. Note that it is not essential for each protrusion 32 to include a yoke 81.

[0028] As shown in Figures 2 and 3, the insulator 34 surrounds most of the stator core 37 as described above. In this embodiment, the insulator 34 covers the outer portion of the annular portion 31, the entire teeth 80, and the portion of the yoke 81 excluding the outer circumferential surface 82a of the yoke 81. That is, most of the teeth 80 and the yoke 81 are housed in the insulator 34, and the outer circumferential surface 82a of the yoke 81 is exposed from the insulator 34. As shown in Figure 2, the outer circumferential surface 82a exposed from the insulator 34 and the magnet 44 of the rotor 40 face each other radially via an air gap G so that a magnetic circuit is formed in the motor 1.

[0029] As shown in Figure 2, the multiple coils 33 are wound around each of the multiple teeth 80 via an insulator 34. In this way, the multiple coils 33 are insulated from the stator core 37. When current from an external power source flows through the multiple coils 33 via the connector 16 and the circuit board 15, magnetic field lines pass through the annular portion 31 of the stator core 37, the teeth 80, and the yoke 81, forming a magnetic circuit in the motor 1. As a result, the rotor 40, which is located outside the stator 30, rotates around the shaft 20 relative to the stator 30.

[0030] Next, we will explain the stator core 37 in more detail.

[0031] Figure 5 is a cross-sectional view of the stator core 37 in the axial direction. Figure 6 is an enlarged view of the upper end of the stator core 37 and its vicinity. As shown in Figures 5 and 6, the stator core 37 includes a plurality of plate-shaped outer magnetic materials 91 (second magnetic material) stacked in the axial direction and a plurality of plate-shaped inner magnetic materials 92 (first magnetic material) stacked in the axial direction.

[0032] As shown in Figures 5 and 6, the multiple outer magnetic bodies 91 surround the multiple inner magnetic bodies 92. The material forming the multiple outer magnetic bodies 91 is not particularly limited as long as it is a magnetic material, but in this embodiment it is silicon steel. Each of the multiple outer magnetic bodies 91 has substantially the same shape, except for the outer magnetic body 91 located at the top and the outer magnetic body 91 located at the bottom. Note that "substantially identical" includes differences that can be considered manufacturing tolerances, for example. Hereinafter, the outer magnetic body 91 located at the top may be referred to as outer magnetic body 91S1, and the outer magnetic body 91 located at the bottom may be referred to as outer magnetic body 91S2. Furthermore, each of the multiple outer magnetic bodies 91 has substantially the same dimensions. That is, in this embodiment, the axial thickness T1 of each of the multiple outer magnetic bodies 91 (including outer magnetic bodies 91S1 and outer magnetic bodies 91S2) is substantially the same. However, the thickness T1 of each of the multiple outer magnetic bodies 91 may be different as long as the dimensions other than the thickness of each of the multiple outer magnetic bodies 91 are substantially the same. In this embodiment, the multiple outer magnetic bodies 91 are housed inside the insulator 34 as described above, stacked and held so as not to move relative to each other and so as to be magnetically connected to one another. In addition to or instead of housing the multiple outer magnetic bodies 91 inside the insulator 34, the multiple outer magnetic bodies 91 may be fixed to each other by crimping, laser welding, or bonding with an adhesive or the like.

[0033] Figure 7 is a radial cross-sectional view of the stator core 37. More specifically, Figure 7 shows the stator core 37 with one of the outer magnetic bodies 91, other than outer magnetic bodies 91S1 and 91S2, cut along the radial direction. As shown in Figure 7, each of the outer magnetic bodies 91 other than outer magnetic bodies 91S1 and 91S2 includes an innermost annular region 91R and a plurality of protruding regions 91C extending radially from the annular region 91R. The annular region 91R has an inner circumferential surface 91Ra, and the area inside the inner circumferential surface 91Ra is generally circularly open. Each of the plurality of protruding regions 91C is formed to be substantially the same shape and dimensions and is arranged at generally equal intervals in the circumferential direction of the annular region 91R. Each of the multiple protruding regions 91C includes a teeth region 91A extending radially outward from the annular region 91R, and a yoke region 91B connected to the outer end of the teeth region 91A. When viewed from the axial direction, the teeth region 91A has a rectangular shape. When viewed from the axial direction, the yoke region 91B is formed such that its circumferential length increases (i.e., its diameter widens) towards the outside, starting from the connection point with the outer end of the teeth region 91A. In each of the multiple outer magnetic materials 91 other than the outer magnetic materials 91S1 and 91S2, the teeth region 91A has a rectangular inner circumferential surface 91D when viewed from the axial direction. That is, a rectangular opening 91E is formed inside this inner circumferential surface 91D when viewed from the axial direction. This rectangular opening 91E extends radially across the entire teeth region 91A. In other words, in the radial direction, the length L1 of the tooth region 91A and the length L2 of the rectangular opening 91E are substantially the same. Furthermore, the length of the rectangular opening 91E in the circumferential direction is not particularly limited, but for example, it may be 50% to 90% of the length of the tooth region 91A in the circumferential direction.

[0034] On the other hand, the tooth region 91A of each of the outer magnetic material 91S1 and outer magnetic material 91S2 does not have a rectangular inner circumferential surface 91D. That is, the tooth region 91A of each of the outer magnetic material 91S1 and outer magnetic material 91S2 does not have the rectangular opening 91E described above. Each of the outer magnetic material 91S1 and outer magnetic material 91S2 has the same shape as the other outer magnetic material 91, except that this rectangular opening 91E is not formed therein.

[0035] As shown in Figures 5 and 6, a stator core 37 is formed by stacking multiple outer magnetic materials 91, including outer magnetic materials 91S1 and 91S2, in the axial direction, thereby forming an annular portion 31 formed by stacking annular regions 91R and a protruding portion 32 formed by stacking protruding regions 91C. Furthermore, by stacking multiple outer magnetic materials 91, excluding outer magnetic materials 91S1 and 91S2, in the axial direction, a rectangular parallelepiped-shaped internal space 95 is formed inside the teeth 80 of the stator core 37, that is, below the outer magnetic material 91S1 and above the outer magnetic material 91S2, with the above-mentioned multiple rectangular openings 91E communicating with each other. This internal space 95 is closed at the upper end by outer magnetic material 91S1 and closed at the lower end by outer magnetic material 91S2. As described above, the entire teeth 80 is housed in the insulator 34. Therefore, the entire internal space 95 is housed within the insulator 34.

[0036] Each of the multiple inner magnetic bodies 92 is a different material from the multiple outer magnetic bodies 91. The material forming the multiple inner magnetic bodies 92 is not particularly limited as long as it is a magnetic material, but in this embodiment it is silicon steel, which is the same material as the outer magnetic body 91. As shown in Figures 5 to 7, each of the multiple inner magnetic bodies 92 has the same shape and dimensions. Specifically, each of the multiple inner magnetic bodies 92 is rectangular when viewed from the axial and radial directions, and has substantially the same dimensions as the rectangular opening 91E when viewed from the axial direction. Furthermore, in the axial direction, each of the multiple inner magnetic bodies 92 has substantially the same thickness. As shown in Figures 5 and 6, the thickness T2 of each of the multiple inner magnetic bodies 92 is thinner than the thickness T1 of each of the multiple outer magnetic bodies 91. The thickness T2 of each of the multiple inner magnetic materials 92 is not particularly limited as long as it is thinner than the thickness T1 of each of the multiple outer magnetic materials 91. For example, if both the outer magnetic material 91 and the inner magnetic material 92 are silicon steel sheets, and the thickness T1 of the outer magnetic material 91 is 0.5 mm, then the thickness T2 of the inner magnetic material 92 may be 0.05 mm or more and 0.1 mm or less.

[0037] As shown in Figures 5 and 6, multiple inner magnetic materials 92 are stacked and housed in each of the internal spaces 95 of the multiple teeth 80, resulting in the internal space 95 being almost completely filled with the multiple inner magnetic materials 92. The upper and lower ends of the multiple inner magnetic materials 92 housed in the internal space 95 are sealed by the outer magnetic materials 91S1 and 91S2. In other words, the entire outer periphery of the multiple inner magnetic materials 92 is covered by the multiple outer magnetic materials 91. Thus, the multiple inner magnetic materials 92 are members that form the interior of the multiple protrusions 32 (teeth 80), while the multiple outer magnetic materials 91 that form the multiple protrusions 32 are members that form the outer periphery surrounding the interior of the multiple protrusions 32 (multiple inner magnetic materials 92). The multiple inner magnetic materials 92 housed in the internal space 95 are magnetically connected to each other and are also magnetically connected to the multiple outer magnetic materials 91 that surround the multiple inner magnetic materials 92. In this embodiment, the multiple inner magnetic bodies 92 housed in the internal space 95 are not fixed to each other by means such as crimping, laser welding, or bonding with adhesive, but are held in such a way that they hardly move relative to each other because they are housed in the internal space 95 and sealed by the outer magnetic bodies 91S1 and 91S2 as described above. However, the multiple inner magnetic bodies 92 may be fixed to each other, or the multiple inner magnetic bodies 92 and the multiple outer magnetic bodies 91 may be fixed with resin or the like.

[0038] In this embodiment, the multiple inner magnetic materials 92 are housed within the multiple outer magnetic materials 91 and the insulator 34. Furthermore, in this embodiment, the multiple inner magnetic materials 92 extend radially across the entire tooth 80, and the radial length L2 of the multiple inner magnetic materials 92 is substantially the same as the radial length L1 of the tooth 80. Moreover, in this embodiment, the number of stacked layers of the multiple inner magnetic materials 92 is greater than the number of stacked layers of the multiple outer magnetic materials 91.

[0039] As described above, the stator core 37 (iron core) of the motor 1 according to this embodiment comprises an annular portion 31 (inner circumference) and a plurality of protrusions 32 extending radially from the annular portion 31. Furthermore, the members forming the interior of the plurality of protrusions 32 (inner magnetic material 92) and the members forming the outer circumference (teeth 80) surrounding the interior of the plurality of protrusions 32 (outer magnetic material 91) are different. The members forming the interior of the plurality of protrusions 32 are a plurality of inner magnetic materials 92 (first magnetic material) stacked in the axial direction of the motor 1, and the members forming the outer circumference (teeth 80) surrounding the interior of the plurality of protrusions 32 are a plurality of outer magnetic materials 91 (second magnetic material) stacked in the axial direction. In this motor 1, in the axial direction, the thickness T2 of each of the plurality of inner magnetic materials 92 (first magnetic material) is thinner than the thickness T1 of each of the plurality of outer magnetic materials 91 (second magnetic material).

[0040] In this embodiment of the motor 1, the outer portion of the stator core 37 is formed of a relatively thick outer magnetic material 91 (second magnetic material), thus ensuring the strength of the stator core 37 (iron core). On the other hand, in the motor 1, the inside of the stator core 37, in particular, the inside of the teeth 80 where the magnetic flux density is expected to be high in this embodiment, is formed of a relatively thin inner magnetic material 92 (first magnetic material), thus reducing the eddy currents generated in the stator core 37, and as a result, iron loss is suppressed and motor efficiency can be improved.

[0041] Furthermore, in the motor 1 of this embodiment, since the inner magnetic material 92 is housed and held inside the outer magnetic material 91, there is no need to fix the inner magnetic materials 92 together by crimping or the like. Therefore, it is possible to make the inner magnetic material 92 thinner without worrying about its strength against crimping or the like. Consequently, when the inner magnetic material 92 is formed from, for example, a silicon steel sheet, it is possible to use a silicon steel sheet that is thinner than the silicon steel sheet thickness that is normally assumed. Therefore, as described above, it is possible to use a silicon steel sheet with a thickness of 0.05 mm or more and 0.1 mm or less, which can further suppress eddy currents. Also, when the inner magnetic material 92 is formed from a material other than a silicon steel sheet (for example, a powdered magnetic material), it may be possible to make the thickness of the inner magnetic material 92 less than 0.05 mm.

[0042] Furthermore, according to the motor 1 of this embodiment, since the multiple inner magnetic bodies 92 are rectangular, molding is easy, resulting in excellent productivity and cost-effectiveness.

[0043] Next, various modifications of the above embodiment will be described.

[0044] (First variation) Figure 8 is an axial cross-sectional view showing a part of the stator core 37 according to this modified example, specifically showing a part of the axial cross-section of the teeth 80. Hatching is omitted in Figure 8 for convenience. As shown in Figure 8, a plurality of inner magnetic materials 92 are housed in the internal space 95 of the teeth 80. The plurality of inner magnetic materials 92 include inner magnetic materials 92 of different thicknesses, specifically including a first inner magnetic material 92a having a first thickness and a second inner magnetic material 92b having a second thickness that is thinner than the first thickness. In this modified example, in the axial direction, the first inner magnetic material 92a is located on the end side (outer magnetic material 91S1 side and outer magnetic material 91S2 side), and the second inner magnetic material 92b is located on the inside. That is, in this modified example, in the axial direction, the thickness of the inner magnetic material 92 located on the end side is greater than the thickness of the inner magnetic material 92 located on the inside. With this configuration, the inner magnetic material 92 on the end side is formed to be relatively thick, which allows for increased strength of the stator core 37 while suppressing eddy currents.

[0045] (Second variation) Figure 9 is an axial cross-sectional view showing a part of the stator core 37 according to this modified example, and specifically shows a part of the axial cross-section of the teeth 80. Hatching is omitted in Figure 9 for convenience. As shown in Figure 9, the internal space 95 of the teeth 80 houses a plurality of inner magnetic materials 92. The plurality of inner magnetic materials 92 include inner magnetic materials 92 of different thicknesses, specifically inner magnetic materials 92a, 92b, 92c, and 92d of different thicknesses. In this modified example, the inner magnetic materials 92a, 92b, 92c, and 92d of different thicknesses are arranged randomly in the axial direction.

[0046] (Third variation) Figure 10 is a radial cross-sectional view showing a part of the stator core 37 according to this modified example, specifically showing a cross-section of one of the multiple protrusions 32. As shown in Figure 10, each of the multiple inner magnetic bodies 92 in this modified example is formed as a rectangle with a radial length L2 shorter than the radial length L1 of the teeth 80. That is, in this modified example, the length of the multiple inner magnetic bodies 92 is shorter than the length of the teeth 80 in the radial direction. Each of the multiple inner magnetic bodies 92 is housed in an internal space 95 having an opening that is substantially the same shape as the planar shape of the inner magnetic body 92. In this modified example, the proportion of the outer magnetic body 91, which is thicker than the inner magnetic body 92, is larger than in the above embodiment, so that the strength of the stator core 37 can be increased while suppressing eddy currents.

[0047] (Fourth variation) Figure 11 is a radial cross-sectional view showing a part of the stator core 37 according to this modified example, specifically showing a cross-section of one of the multiple protrusions 32. As shown in Figure 11, each of the multiple inner magnetic bodies 92 in this modified example extends radially across the entire tooth 80. Specifically, each of the multiple inner magnetic bodies 92 extends radially from the boundary between the yoke region 91B and the tooth region 91A of the outer magnetic body 91 to the annular region 91R of the outer magnetic body 91, and is longer than the length of the tooth 80 in the radial direction. Furthermore, each of the multiple inner magnetic bodies 92, when viewed from the axial direction, includes a first rectangular portion 92f extending radially and a second substantially rectangular portion 92s extending roughly circumferentially, and is generally formed in a T-shape. The first portion 92f extends into the annular region 91R, and the second portion 92s is connected to the end of the first portion 92f located within the annular region 91R. The width (length in the circumferential direction) of the second portion 92s may be longer than, shorter than, or the same as the length in the circumferential direction of the teeth region 91A. Each of the outer magnetic bodies 91, excluding the outer magnetic bodies 91S1 and 91S2, has a hole formed therein that has a planar shape and dimensions that are approximately the same as the planar shape (approximately T-shaped) of the inner magnetic body 92. Each of the inner magnetic bodies 92 is housed and held in an internal space 95 formed by the communication of the holes when the outer magnetic bodies 91 are stacked. In this modified example, the proportion of the inner magnetic body 92, which is thinner than the outer magnetic body 91, is larger than in the above embodiment, so that eddy currents can be further suppressed.

[0048] (Fifth variation) Figure 12 is a radial cross-sectional view showing a part of the stator core 37 according to this modified example, specifically showing a cross-section of one of the multiple protrusions 32. As shown in Figure 12, each of the multiple inner magnetic bodies 92 in this modified example extends radially across the entire teeth 80. Specifically, each of the multiple inner magnetic bodies 92 extends radially from the boundary between the annular region 91R and the teeth region 91A of the outer magnetic body 91 to the yoke region 91B of the outer magnetic body 91, and is longer than the length of the teeth 80 in the radial direction. Furthermore, each of the multiple inner magnetic bodies 92, when viewed from the axial direction, includes a first rectangular portion 92f extending radially and a second substantially rectangular portion 92s extending roughly circumferentially, and is generally formed in a T-shape. The first portion 92f extends into the yoke region 91B, and the second portion 92s is connected to the end of the first portion 92f in the yoke region 91B. The width (length in the circumferential direction) of the second portion 92s may be longer than, shorter than, or the same as the length in the circumferential direction of the teeth region 91A. Each of the outer magnetic bodies 91, excluding the outer magnetic bodies 91S1 and 91S2, has a hole formed therein that has a planar shape and dimensions that are approximately the same as the planar shape (approximately T-shaped) of the inner magnetic body 92. Each of the inner magnetic bodies 92 is housed and held in an internal space 95 formed by the communication of the holes when the outer magnetic bodies 91 are stacked. In this modified example, the proportion of the inner magnetic body 92, which is thinner than the outer magnetic body 91, is larger than in the above embodiment, so that eddy currents can be further suppressed.

[0049] (Sixth variation) Figure 13 is a radial cross-sectional view showing a part of the stator core 37 according to this modified example, specifically showing a cross-section of one of the multiple protrusions 32. As shown in Figure 13, each of the multiple inner magnetic bodies 92 in this modified example extends radially across the entire tooth 80. Specifically, each of the multiple inner magnetic bodies 92 extends radially from the annular region 91R of the outer magnetic body 91 to the yoke region 91B of the outer magnetic body 91, and is longer than the length of the tooth 80 in the radial direction. Furthermore, each of the multiple inner magnetic bodies 92, when viewed from the axial direction, includes a first rectangular portion 92f extending radially, and a second and third roughly rectangular portion 92s and 92t extending roughly circumferentially, and is generally formed in an I-shape. The first portion 92f extends from within the annular region 91R to within the yoke region 91B. The second portion 92s is connected to the end of the first portion 92f in the annular region 91R. A third portion 92t is connected to the end of the first portion 92f in the yoke region 91B. The widths (circumferential lengths) of the second portion 92s and the third portion 92t may be longer, shorter, or the same as the circumferential length of the teeth region 91A. Each of the outer magnetic bodies 91, excluding outer magnetic bodies 91S1 and 91S2, has a hole formed therein that has a planar shape and dimensions that are approximately the same as the planar shape (approximately I-shaped) of the inner magnetic body 92. Each of the inner magnetic bodies 92 is housed and held in an internal space 95 formed by the communication of the holes when the outer magnetic bodies 91 are stacked. In this modified example, the proportion of the inner magnetic body 92, which is thinner than the outer magnetic body 91, is larger than in the above embodiment, so eddy currents can be further suppressed.

[0050] (Seventh variation) Figure 14 is a radial cross-sectional view showing the stator core 37 according to this modified example. As shown in Figure 14, each of the multiple inner magnetic bodies 92 in this modified example is formed in an annular shape. Specifically, each of the inner magnetic bodies 92 includes an annular second portion 92s and a plurality of first portions 92f extending radially from the second portion 92s. Each of the plurality of first portions 92f is rectangular when viewed from the axial direction and extends radially in each of the plurality of tooth regions 91A of the outer magnetic body 91. In this modified example, each of the plurality of first portions 92f extends to the boundary between the tooth region 91A and the yoke region 91B of the outer magnetic body 91. The second portion 92s is circular when viewed from the axial direction and is located within the annular region 91R of the outer magnetic body 91. In this configuration, the inner magnetic body 92 of this modified example has a structure in which a first portion 92f located in each of the multiple tooth regions 91A and a second portion 92s located in the annular region 91R are integrated. Each of the outer magnetic bodies 91, excluding the outer magnetic bodies 91S1 and 91S2, has a hole formed therein that has a planar shape and dimensions that are generally the same as the planar shape of the inner magnetic body 92. Each of the inner magnetic bodies 92 is housed and held in an internal space 95 formed by the communication of the holes when the outer magnetic bodies 91 are stacked. In this modified example, the proportion of the inner magnetic body 92, which is thinner than the outer magnetic body 91, is larger than in the above embodiment, so that eddy currents can be further suppressed.

[0051] The present invention has been described above with reference to the above embodiments and their variations, but the present invention is not limited thereto.

[0052] For example, the number of stacked inner magnetic materials 92 may be the same as or greater than the number of stacked outer magnetic materials 91. Specifically, when a first group consisting of multiple inner magnetic materials 92 stacked in the axial direction and a second group consisting of multiple inner magnetic materials 92 stacked in the axial direction are adjacent in the axial direction, and at least one outer magnetic material 91 is interposed between the first group and the second group, the number of stacked inner magnetic materials 92 may be the same as or greater than the number of stacked outer magnetic materials 91.

[0053] Furthermore, the entire outer periphery of the multiple inner magnetic bodies 92 does not necessarily have to be covered by the multiple outer magnetic bodies 91. For example, when the multiple outer magnetic bodies 91 and the multiple inner magnetic bodies 92 housed in the internal space 95 are fixed together with an adhesive or the like, the multiple inner magnetic bodies 92 are prevented from departing from the internal space 95, so it is not necessarily required to seal the internal space 95 with the outer magnetic bodies 91S1 and 91S2. In this case, the entire outer periphery of the multiple inner magnetic bodies 92 is not covered by the multiple outer magnetic bodies 91.

[0054] In addition to insulating the multiple coils 33 and the stator core 37 with the insulator 34, or instead, the stator core 37 may be coated with an insulating paint so that the entire outer circumference of the multiple inner magnetic materials 92 is covered by the multiple outer magnetic materials 91 and the insulating paint.

[0055] Furthermore, for example, the stator core 37 may have an internal space 95 (first internal space) with a radial length longer than the radial length of the teeth 80, an internal space 95 (second internal space) with the same radial length as the teeth 80, and an internal space 95 (third internal space) with a radial length shorter than the radial length of the teeth 80. In such a case, the radial length of the multiple inner magnetic materials 92 housed in the first internal space may be longer than the radial length of the teeth 80, the radial length of the multiple inner magnetic materials 92 housed in the second internal space may be the same as the radial length of the teeth 80, and the radial length of the multiple inner magnetic materials 92 housed in the third internal space may be shorter than the radial length of the teeth 80. In other words, in such an example, the length of some of the multiple inner magnetic materials 92 may be longer than the length of the teeth 80, the length of other parts of the multiple inner magnetic materials 92 may be equal to the length of the teeth 80, and the length of yet another part of the multiple inner magnetic materials 92 may be shorter than the length of the teeth 80.

[0056] Furthermore, in the above embodiments and their variations, the material of the outer magnetic body 91 (e.g., silicon steel) and the material of the multiple inner magnetic bodies 92 (e.g., silicon steel) are shown to be the same. However, for example, the inner magnetic bodies 92 may be formed from a material that has a higher eddy current suppression effect than the outer magnetic body. Examples of materials include laminated thin films of amorphous metal or solidified amorphous alloy powder.

[0057] Furthermore, although the above embodiments and their variations describe an example where the core is a stator core 37, the core may also be a rotor core.

[0058] Furthermore, those skilled in the art may, in accordance with conventionally known knowledge, modify the present invention to other types of motors such as inner-rotor type brushless motors, brushed motors, and fan motors. Such modifications, insofar as they still possess the configuration of the present invention, are of course included within the scope of the present invention. [Explanation of Symbols]

[0059] 1...Motor, 31...Ring section (inner circumference), 32...Protruding section, 34...Insulator, 37...Stator core (iron core), 80...Teeth, 81...Yoke, 91...Outer magnetic material (second magnetic material), 92...Inner magnetic material (first magnetic material)

Claims

1. A motor equipped with an iron core, The iron core comprises an inner circumference and a plurality of protrusions extending radially from the inner circumference. The member forming the interior of the plurality of protrusions and the member forming the outer periphery surrounding the interior of the plurality of protrusions are different. The members forming the interior of the plurality of protrusions are a plurality of first magnetic materials stacked in the axial direction of the motor, The member forming the outer periphery surrounding the interior of the plurality of protrusions is a plurality of second magnetic materials stacked in the axial direction. In the axial direction, the thickness of each of the plurality of first magnetic materials is thinner than the thickness of each of the plurality of second magnetic materials. The entire outer periphery of the plurality of first magnetic materials is covered by the plurality of second magnetic materials. The first magnetic material contains an amorphous metal, in this motor.

2. The motor according to claim 1, wherein the number of stacked layers of the plurality of first magnetic materials is greater than the number of stacked layers of the plurality of second magnetic materials.

3. The motor according to claim 1, further comprising an insulator, wherein the plurality of first magnetic materials are housed in the plurality of second magnetic materials and the insulator.

4. The motor according to claim 1, wherein the iron core is coated with an insulating paint, and the entire outer periphery of the plurality of first magnetic materials is covered with the plurality of second magnetic materials and the insulating paint.

5. The motor according to claim 1, wherein the protrusion comprises teeth and a yoke, and at least a portion of the plurality of first magnetic materials extends over the entire teeth.

6. The motor according to claim 1, wherein the protrusion comprises teeth and a yoke, and in the radial direction of the motor, the length of at least a portion of the plurality of first magnetic materials is shorter than the length of the teeth.

7. The motor according to claim 1, wherein the plurality of first magnetic materials include first magnetic materials of different thicknesses.

8. The motor according to claim 7, wherein the first magnetic materials of different thicknesses are randomly stacked in the axial direction.

9. The motor according to claim 7, wherein the thickness of the first magnetic material located at the end in the axial direction is greater than the thickness of the first magnetic material located on the inside.

10. The motor according to claim 1, wherein the materials of the plurality of first magnetic materials and the materials of the plurality of second magnetic materials are different.

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