Motor

Abstract

To provide a motor that can be lightened in weight.SOLUTION: A motor 10 includes a rotor 12, a plurality of coils 16, and an annularly formed stator core 26. Each coil 16 includes an opposing part 36 and a coil end part 38. The opposing parts 36 of the plurality of coils 16 are arranged along an internal peripheral surface of the stator core 26. The coil end part 38 of the plurality of coils 16 on one side in an axial direction and the coil end part 38 thereof on the other side in the axial direction are arranged along an end surface of the stator core 26 in an axial direction. A lightening hole 26B is formed in a portion on a side opposite to the opposing part 36 in the stator core 26. The shape, dimension, number and arrangement of the lightening hole 26B are set such that the maximum magnetic flux density at the inside of the stator core 26 at a position closest to the opposing part in the lightening hole 26B is less than the saturation magnetic flux density of a material that forms the stator core 26.SELECTED DRAWING: Figure 4

Description

[Technical field]

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

[0002] The following Patent Document 1 discloses a motor configured by arranging a plurality of coils along a fixed ring formed in an annular shape. The motor described in this document is configured by winding a wire in a rectangular shape and bending both axial ends in the radial direction to form A-phase coils and B-phase coils, which are alternately arranged along the circumferential direction of the fixed ring. In addition, the coil end portions, which are both axial ends of the A-phase coils and B-phase coils, are arranged along both axial end faces of the fixed ring. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 4-58747 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in a configuration in which the coil end portion of the coil is disposed along the axial end face of the fixing ring as in the configuration described in Patent Document 1, the radial dimension of the fixing ring needs to be set to a dimension corresponding to the radial dimension of the coil end portion. In other words, there is a restriction on reducing the radial dimension of the fixing ring. As a result, it is difficult to reduce the weight of the motor.

[0005] In consideration of the above, an object of the present disclosure is to obtain a motor that can be made lighter. [Means for solving the problem]

[0006] A motor (10, 54, 56, 64, 66, 68, 84, 86, 90, 94) that solves the above problems comprises: a rotor (12) having a magnet (18) and supported for rotation; a plurality of coils (16) each formed by winding a conductive winding (30) in an annular shape, with parts of the winding being arranged side by side in the circumferential direction and arranged radially opposite the axial center of the magnet; and coil end portions (38) forming one axial side and the other axial side portions of the opposing portions, the plurality of coils being arranged in an annular shape; and a core (26) formed in an annular shape, the opposing portions of the plurality of coils being arranged along an inner peripheral surface or an outer peripheral surface, at least one of the coil end portions on one axial side and the coil end portions on the other axial side of the plurality of coils being arranged along an axial end face, and having a lightening portion (26B, 26C) formed in a portion opposite the opposing portions. 、 The shape, dimensions, number and arrangement of the hollowed-out portions are set so that the maximum magnetic flux density inside the core at the position in the hollowed-out portion closest to the opposing portion is less than the saturation magnetic flux density of the material forming the core.

[0007] By configuring it in this way, it is possible to reduce the weight. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a partially cutaway perspective view showing a rotor and a stator of the motor according to the first embodiment. [Diagram 2] 2 is a side cross-sectional view showing a cross section of the motor taken along the axial direction. FIG. [Diagram 3] FIG. 2 is a plan view showing a stator and a rotor. [Figure 4] FIG. 2 is a cross-sectional view showing a stator and a rotor. [Diagram 5] FIG. [Figure 6] FIG. [Figure 7] FIG. [Figure 8]4 is an enlarged plan view showing a boundary between an opposing portion and a coil end portion. FIG. [Figure 9] 4 is an enlarged cross-sectional side view showing a boundary between an opposing portion and a coil end portion. FIG. [Figure 10] FIG. 2 is a schematic diagram for explaining connections of a U phase, a V phase, and a W phase. [Figure 11] FIG. 2 is a schematic diagram for explaining connections and arrangements of U-phase, V-phase, and W-phase. [Figure 12] 4 is a side cross-sectional view showing a cross section of a part of the stator taken along the axial direction. FIG. [Figure 13] 4 is a perspective view showing an insulator and a coil supported by a rotor core via the insulator. FIG. [Figure 14] 14 is a perspective view showing an insulator and a coil supported by a rotor core via the insulator, illustrating an example in which an insulator different from that in FIG. 13 is applied. [Figure 15] 2 is a perspective view showing an insulator and a U-phase coil, a V-phase coil, and a W-phase coil supported on a rotor core via the insulator. FIG. [Figure 16] FIG. 11 is a cross-sectional view showing a stator and a rotor of a motor according to a second embodiment. [Figure 17] FIG. 11 is a perspective view illustrating a stator core of a motor according to a third embodiment. [Figure 18] FIG. 11 is a cross-sectional view showing a stator and a rotor of a motor according to a fourth embodiment. [Figure 19] FIG. 13 is a perspective view showing a stator core of a motor according to a fifth embodiment. [Figure 20] FIG. 13 is a side cross-sectional view showing a stator of a motor according to a fifth embodiment. [Figure 21] FIG. 13 is a plan view showing a stator core of a motor according to a sixth embodiment. [Figure 22] FIG. 13 is a plan view showing a stator core of a motor according to a seventh embodiment. [Figure 23] FIG. 13 is a perspective view showing a stator core of a motor according to an eighth embodiment. [Figure 24]FIG. 13 is a schematic diagram showing the structure of a stator core of a motor according to an eighth embodiment. [Diagram 25] FIG. 13 is a perspective view showing a stator core of a motor according to a ninth embodiment. [Figure 26] FIG. 23 is a perspective view showing a stator core of a motor according to a tenth embodiment. [Figure 27] FIG. 23 is a perspective view showing a stator core of a motor according to an eleventh embodiment. [Figure 28] FIG. 23 is a cross-sectional view showing a portion of a stator core of a motor according to a twelfth embodiment. [Figure 29] FIG. 23 is a cross-sectional view showing a portion of a stator core of a motor according to a thirteenth embodiment. [Diagram 30] FIG. 23 is a cross-sectional view showing a portion of a stator core of a motor according to a fourteenth embodiment. [Diagram 31] FIG. 23 is a cross-sectional view showing a portion of a stator core of a motor according to a fifteenth embodiment. [Diagram 32] FIG. 23 is a cross-sectional view showing a portion of a stator core of a motor according to a sixteenth embodiment. [Diagram 33] FIG. 23 is a cross-sectional view showing a portion of a stator core of a motor according to a seventeenth embodiment. [Diagram 34] FIG. 23 is a cross-sectional view showing a portion of a stator core of a motor according to an eighteenth embodiment. [Diagram 35] FIG. 23 is a side cross-sectional view showing a stator of a motor according to a nineteenth embodiment. [Diagram 36] FIG. 23 is a perspective view showing an insulator of a motor according to a twentieth embodiment. [Figure 37] 20. FIG. 21 is an oblique view showing an insulator of a motor according to a 20th embodiment, and a U-phase coil, a V-phase coil, and a W-phase coil supported on a rotor core via the insulator. [Figure 38] FIG. 21 is an enlarged plan view showing a portion of the motor according to the twenty-first embodiment. [Figure 39] FIG. 22 is an enlarged plan view showing a portion of the motor according to the twenty-second embodiment. [Figure 40A] FIG. 23 is an enlarged plan view showing a portion of the motor according to the twenty-third embodiment. [Figure 40B]FIG. 24 is an enlarged plan view showing a portion of the motor according to the twenty-fourth embodiment. [Diagram 41] FIG. 25 is an enlarged plan view showing a portion of the motor according to the twenty-fifth embodiment. [Diagram 42] FIG. 26 is a schematic diagram showing a rotor and a stator of a motor according to a 26th embodiment. [Diagram 43] FIG. 27 is a schematic diagram showing a rotor and a stator of a motor according to a 27th embodiment. [Diagram 44] 11A to 11C are side cross-sectional views for explaining variations in bending of the coil end portion. [Diagram 45] 11A to 11C are side cross-sectional views for explaining variations in bending of the coil end portion. [Diagram 46] 11A to 11C are side cross-sectional views for explaining variations in bending of the coil end portion. [Figure 47] 11A to 11C are side cross-sectional views for explaining variations in bending of the coil end portion. [Figure 48] 5A and 5B are diagrams for explaining the positional relationship between a coil end portion and a magnet. [Figure 49] 11A to 11C are enlarged perspective views for explaining variations of the terminal portions of the windings that form the coil. [Figure 50] 11A to 11C are enlarged perspective views for explaining variations of the terminal portions of the windings that form the coil. [Figure 51] 11A to 11C are enlarged perspective views for explaining variations of the terminal portions of the windings that form the coil. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (First embodiment) A motor 10 according to a first embodiment of the present disclosure will be described with reference to Figs. 1 to 15. First, the overall configuration of the motor will be described, and then the configuration of the main parts of this embodiment will be described. Note that the directions of arrows Z, R, and C, as appropriate, shown in the drawings respectively indicate one side in the rotational axial direction, the outer side in the rotational radial direction, and one side in the rotational circumferential direction of the rotor 12 described below. In addition, hereinafter, when the axial direction, radial direction, or circumferential direction is simply indicated, it is assumed that the axial direction, radial direction, or circumferential direction of the rotor 12 is indicated unless otherwise specified.

[0010] 1 to 3, motor 10 of this embodiment is an inner rotor type brushless motor in which rotor 12 as a rotating body is disposed radially inside stator 14. Note that the drawings shown in Figs. 1 to 5 are drawings of motor 10 etc. shown as an example, and there are some parts in which the number of coils 16 and the number of magnets 18 do not match those described below.

[0011] The rotor 12 includes a rotating shaft 22 rotatably supported via a pair of bearings 20, a rotor core 24 formed in a bolt-type cylindrical shape and fixed to the rotating shaft 22, and a plurality of magnets 18 fixed to the radially outer surface of the rotor core 24.

[0012] The rotor core 24 includes a first cylindrical portion 24A to which the rotating shaft 22 is fixed by press-fitting or the like, a second cylindrical portion 24B disposed radially outside the first cylindrical portion 24A and formed cylindrically, and a disk-shaped connecting plate portion 24C that radially connects one axial end of the first cylindrical portion 24A to one axial end of the second cylindrical portion 24B. The outer peripheral surface, which is the radially outer surface of the second cylindrical portion 24B, is formed into a cylindrical surface along the circumferential direction. A magnet 18, which will be described later, is fixed to the outer peripheral surface of the second cylindrical portion 24B.

[0013] The magnets 18 are formed using a magnetic compound having an intrinsic coercivity Hc of 400 kA / m or more and a residual magnetic flux density Br of 1.0 T or more. 11TiN, Nd2Fe 14 B, SmFe 17 The rotor core 24 is formed of a magnetic compound such as N3, FeNi, etc. A plurality of magnets 18 are fixed to the outer peripheral surface of the second cylindrical portion 24B of the rotor core 24. The magnets 18 whose radially outer surfaces are N poles and the magnets 18 whose radially outer surfaces are S poles are arranged alternately in the circumferential direction. The number of magnets 18 may be appropriately set in consideration of the output required for the motor 10, etc.

[0014] 5, the stator 14 includes a stator core 26 as a core formed in an annular shape, an insulator 28 attached to the stator core 26 by adhesion, fitting, or the like, and a plurality of coils 16 attached to the stator core 26 via the insulators 28. The stator 14 of this embodiment has a teethless structure in which no part of the stator core 26 is disposed inside the coils 16.

[0015] As shown in FIG. 1 and FIG. 5, the stator core 26 is formed in an annular shape using a magnetic material such as steel. A cross section of the stator core 26 cut along the axial direction and the radial direction has a rectangular cross section with the axial direction as the longitudinal direction. The stator core 26 is arranged coaxially with the rotor 12, and the axial center position of the stator core 26 and the axial center position of the multiple magnets 18 fixed to the rotor core 24 coincide with each other in the axial direction. As shown in FIG. 2, the stator core 26 is supported by a housing 74 as a core support member constituting the outer shell of the motor 10. Here, the stator core 26 is arranged inside the housing 74 formed in a cylindrical shape with a bottom. The stator core 26 is supported by the housing 74 by being press-fitted into the housing 74, for example. As a result, the stator 14 is supported by the housing 74. Incidentally, a step portion 74A is formed on one axial side of a portion of the housing 74 into which the stator core 26 is press-fitted, with which a part of the insulator 28, which will be described later, comes into contact.

[0016] 1 and 5, the insulator 28 is formed using a highly insulating material such as a resin material. The insulator 28 covers the radially inner surface and both axial end surfaces of the stator core 26 when the insulator 28 is attached to the stator core 26. The specific configuration of the insulator 28 will be described in detail later.

[0017] As shown in Figs. 5 to 7, the coils 16 are formed by winding a conductive wire (conductor) in a circular shape. Here, as shown in Figs. 6 and 7, the winding 30 forming the coil 16 of this embodiment has a rectangular cross section in which a dimension L1 of the winding 30 in a first direction (arrow A1 direction) is set to be larger than a dimension L2 in a second direction (arrow A2) perpendicular to the first direction, in a cross section cut along the longitudinal direction. The winding 30 may be a wire assembly formed by bundling conductive wires. The resistance between the bundled wires is larger than the resistance of the wire itself. The cross-sectional shape of the winding 30 may be an oval or elliptical shape. In general, an enameled wire is preferably used for the winding 30, and the conductive material may be copper or aluminum.

[0018] As shown in Figures 5 to 7, the stator 14 of this embodiment is configured to include two types of coils 16 with different axial dimensions. Here, the coils 16 shown in Figure 6 are referred to as short coils 32. Also, the coils 16 shown in Figure 7 are referred to as long coils 34. The number of coils 16 may be appropriately set in consideration of the output required of the motor 10, etc.

[0019] As shown in Fig. 6, the short coil 32 is formed by winding the winding 30 in a rectangular shape so as to be stacked in the second direction (the direction of the arrow A2), and then bending both ends in the axial direction toward the radially outward direction. As a result, the short coil 32 has a pair of opposing parts 36 in which parts of the winding 30 are arranged side by side in the circumferential direction and spaced apart from each other in the circumferential direction, one coil end part 38 that connects the ends on one axial side of the pair of opposing parts 36 in the circumferential direction, and the other coil end part 38 that connects the ends on the other axial side of the pair of opposing parts 36 in the circumferential direction. In addition, the terminal part 40 on one side of the winding 30 forming the short coil 32 extends from one circumferential side of the opposing part 36 on one circumferential side to one axial side. In addition, the terminal part 40 on the other side of the winding 30 forming the short coil 32 extends from one circumferential side of the opposing part 36 on the other circumferential side to one axial side. By arranging the terminal portion 40 in this manner, in the short coil 32 of this embodiment, the number of layers of the winding 30 at the coil end portion 38 on one axial side is smaller than the number of layers of the winding 30 at the coil end portion 38 on the other axial side. More specifically, the number of layers of the winding 30 at the coil end portion 38 on one axial side is six, and the number of layers of the winding 30 at the coil end portion 38 on the other axial side is seven. The number of layers of the winding 30 at the pair of opposing portions 36 is seven.

[0020] Here, a manufacturing process of the short coil 32 will be briefly described. In the manufacturing process of the short coil 32, first, the winding 30 is wound in a rectangular shape so that the winding 30 is laminated in the second direction (the direction of the arrow A2). Next, the rectangularly wound portion of the short coil 32, excluding the pair of terminal portions 40, is joined using a joining member not shown. As a result, the portion (stacked winding 30) forming the pair of opposing portions 36, the coil end portion 38 on one axial side, and the coil end portion 38 on the other axial side in the short coil 32 is joined inseparably in the second direction. Next, as shown in Figs. 8 and 9, the portion of the short coil 32 forming the coil end portion 38 on one axial side and the coil end portion 38 on the other axial side is bent at a substantially right angle toward the radially outward side. That is, the boundary between the pair of coil end portions 38 and the pair of opposing portions 36 is bent at a substantially right angle in the first direction. This forms the short coil 32, in which the pair of opposing portions 36 are arranged along the radially inner surface of the stator core 26 and the coil end portions 38 on one and the other axial sides are respectively arranged along both axial end surfaces of the stator core 26. The short coil 32 is manufactured through the above steps.

[0021] 6 and 7, the long coil 34 has the same configuration as the short coil 32, except that the axial dimension H2 of the long coil 34 is larger than the axial dimension H1 of the short coil 32. Here, the parts of the long coil 34 that correspond to the short coil 32 are given the same reference numerals as the short coil 32, and the description of these parts will be omitted. The long coil 34 is manufactured through the same process as the short coil 32. Incidentally, the length of the winding 30 forming the long coil 34 is longer than the length of the winding 30 forming the short coil 32. As a result, the electrical resistance of the long coil 34 is higher than the electrical resistance of the short coil 32.

[0022] As shown in FIG. 10, the coils 16 are connected in a star connection as an example. In this example, the U-phase 42U, the V-phase 42V, and the W-phase 42W are each configured to include two short coils 32 and two long coils 34. In the U-phase 42U, the four coils 16 are connected in series in the order of the long coil 34, the short coil 32, the long coil 34, and the short coil 32 from the neutral point 44 side. In the V-phase 42V, the four coils 16 are connected in series in the order of the long coil 34, the short coil 32, the long coil 34, and the short coil 32 from the neutral point 44 side. In the W-phase 42W, the four coils 16 are connected in series in the order of the short coil 32, the long coil 34, the short coil 32, and the long coil 34 from the neutral point 44 side. The coils 16 are connected to each other using a connecting member such as a bus bar.

[0023] Here, in the U phase 42U, the range from the short coil 32 farthest from the neutral point 44 to the neutral point 44 is referred to as the U-phase coil connection body 46U. In addition, in the V phase 42V, the range from the short coil 32 farthest from the neutral point 44 to the neutral point 44 is referred to as the V-phase coil connection body 46V. Furthermore, in the W phase 42W, the range from the long coil 34 farthest from the neutral point 44 to the neutral point 44 is referred to as the W-phase coil connection body 46W. In this embodiment, the number of long coils 34 and the number of short coils 32 are set to the same number in the coil connection bodies 46U, 46V, 46W of each phase, so that the combined resistance of the coil connection bodies 46U, 46V, 46W of each phase is the same. Here, the combined resistance of the coil connections 46U, 46V, 46W of each phase being the same means that the difference between the combined resistance of the coil connection 46U of one phase and the combined resistance of the coil connections 46V, 46W of the other phase is within plus or minus 5%.

[0024] Fig. 11 shows the relative positions of the coils 16 in the U phase 42U, the coils 16 in the V phase 42V, and the coils 16 in the W phase 42W. As shown in Fig. 11 and Fig. 12, the short coil 32 farthest from the neutral point 44 in the U phase 42U and the short coil 32 farthest from the neutral point 44 in the V phase 42V are arranged adjacent to each other in the circumferential direction along the stator core 26. In addition, the long coil 34 farthest from the neutral point 44 in the W phase 42W is arranged so as to straddle the short coil 32 farthest from the neutral point 44 in the U phase 42U and the short coil 32 farthest from the neutral point 44 in the V phase 42V.

[0025] In addition, the short coil 32 farthest from the neutral point 44 in the V phase 42V and the short coil 32 on the opposite side of the neutral point 44 in the W phase 42W are arranged adjacent to each other in the circumferential direction along the stator core 26. Furthermore, the long coil 34 on the opposite side of the neutral point 44 in the U phase 42U is arranged so as to straddle the short coil 32 farthest from the neutral point 44 in the V phase 42V and the short coil 32 on the opposite side of the neutral point 44 in the W phase 42W.

[0026] In addition, the short coil 32 on the opposite side of the neutral point 44 in the W phase 42W and the short coil 32 on the neutral point 44 side in the U phase 42U are arranged adjacent to each other in the circumferential direction along the stator core 26. Furthermore, the long coil 34 on the opposite side of the neutral point 44 in the V phase 42V is arranged so as to straddle the short coil 32 on the opposite side of the neutral point 44 in the W phase 42W and the short coil 32 on the neutral point 44 side in the U phase 42U.

[0027] In addition, the short coil 32 on the neutral point 44 side in the U phase 42U and the short coil 32 on the neutral point 44 side in the V phase 42V are arranged adjacent to each other in the circumferential direction along the stator core 26. Furthermore, the long coil 34 on the neutral point 44 side in the W phase 42W is arranged so as to straddle the short coil 32 on the neutral point 44 side in the U phase 42U and the short coil 32 on the neutral point 44 side in the V phase 42V.

[0028] In addition, the short coil 32 on the neutral point 44 side in the V phase 42V and the short coil 32 on the neutral point 44 side in the W phase 42W are arranged adjacent to each other in the circumferential direction along the stator core 26. Furthermore, the long coil 34 on the neutral point 44 side in the U phase 42U is arranged so as to straddle the short coil 32 on the neutral point 44 side in the V phase 42V and the short coil 32 on the neutral point 44 side in the W phase 42W.

[0029] In addition, the short coil 32 on the neutral point 44 side in the W phase 42W and the short coil 32 farthest from the neutral point 44 in the U phase 42U are arranged adjacent to each other in the circumferential direction along the stator core 26. Furthermore, the long coil 34 on the neutral point 44 side in the V phase 42V is arranged so as to straddle the short coil 32 on the neutral point 44 side in the W phase 42W and the short coil 32 farthest from the neutral point 44 in the U phase 42U.

[0030] Here, as shown in FIG. 12 and FIG. 13, the insulator 28 to which each coil 16 is attached includes an inner surface covering portion 28A covering the radially inner surface of the stator core 26, a pair of axial end surface covering portions 28B covering both axial end surfaces of the stator core 26, and a pair of outer circumferential flange portions 28C extending in the axial direction from the radially outer ends of the pair of axial end surface covering portions 28B. The insulator 28 of this embodiment has a split structure that can be split in the axial direction at the axial center of the inner surface covering portion 28A. The insulator 28 also includes a plurality of circumferential positioning portions 28D for positioning the short coil 32 in the circumferential direction. The plurality of circumferential positioning portions 28D are formed in a convex shape toward the radially inner side from the outer circumferential flange portion 28C and are arranged at equal intervals along the circumferential direction. The coil end portion 38 of the short coil 32 is arranged between a pair of circumferential positioning portions 28D adjacent to each other in the circumferential direction, so that the short coil 32 is positioned in the circumferential direction. Although the multiple circumferential positioning portions 28D may be provided on one outer circumferential flange portion 28C, they may be provided on both outer circumferential flange portions 28C. Also, as shown in Fig. 14, the portion corresponding to the inner surface covering portion 28A may be a sheet-like paper insulator, and the other portion may be an insulator 29 having a similar configuration to the insulator 28 shown in Fig. 13. The same reference numerals as those corresponding to the insulator 28 are used for the portions of the insulator 29 shown in Fig. 14 that correspond to the insulator 28 shown in Fig. 13.

[0031] 2 and 4, the insulator 28 includes a convex core engaging portion 28J that protrudes from the shaft end face covering portion 28B on one axial side toward the stator core 26, and a convex core engaging portion 28J that protrudes from the shaft end face covering portion 28B on the other axial side toward the stator core 26. The core engaging portion 28J engages with a lightening hole 26B, which will be described later, thereby restricting circumferential displacement of the insulator 28 relative to the stator core 26.

[0032] As shown in Figs. 2 and 5, the insulator 28 includes a radially outer flange portion 28K as an axial reference portion that protrudes radially outward from the radially outer surface of the outer circumferential flange portion 28C on one axial side. The radially outer flange portion 28K is formed in an annular shape when viewed from the axial direction. The insulator 28 also includes a plurality of notches 28L as a circumferential reference portion recessed toward the outer circumferential flange portion 28C on one axial side by cutting out the radially outer flange portion 28K. The plurality of notches 28L are disposed at equal intervals along the circumferential direction. The outer circumferential flange portion 28C on the other axial side also includes a plurality of notches 28L as a circumferential reference portion recessed toward the outer circumferential flange portion 28C on the other axial side. When the stator core 26 is press-fitted into the housing 74, the radially outer flange portion 28K of the insulator 28 abuts against the stepped portion 74A of the housing 74, thereby positioning the stator core 26 in the axial direction relative to the housing 74. When the stator core 26 is press-fitted into the housing 74, the cutout portion 28L of the insulator 28 engages with a portion of the housing 74, thereby positioning the stator core 26 in the circumferential direction relative to the housing 74.

[0033] As shown in Fig. 11, Fig. 12 and Fig. 15, the facing portions 36 of the short coils 32 and the facing portions 36 of the long coils 34 are disposed along the radially inner surface of the stator core 26 via the inner covering portion 28A of the insulator 28, and are disposed at the same position in the radial direction. In detail, in the state shown in Fig. 15, the facing portions 36 on one circumferential side of the U-phase short coils 32 and the facing portions 36 on the other circumferential side of the V-phase short coils 32 that are adjacent in the circumferential direction are disposed adjacent to each other in the circumferential direction, and the facing portions 36 on one circumferential side of the U-phase short coils 32 and the facing portions 36 on the other circumferential side of the V-phase short coils 32 that are adjacent in the circumferential direction are disposed between a pair of facing portions 36 of the W-phase long coils 34. As shown in Fig. 11 and Fig. 15, the facing portions 36 of the other short coils 32 and the facing portions 36 of the other long coils 34 are also disposed along the radially inner surface of the stator core 26 in a similar relationship. In addition, with the axial center position of the opposing portion 36 of the short coil 32 and the axial center position of the opposing portion 36 of the long coil 34 and the axial center position of the magnet 18 aligned in the axial direction, the opposing portions 36 of the short coil 32 and the opposing portions 36 of the long coil 34 and the magnet 18 are arranged facing each other in the radial direction. In addition, the first direction of the windings 30 constituting the opposing portions 36 of the short coil 32 and the opposing portions 36 of the long coil 34 is directed towards the magnet 18.

[0034] As shown in Figs. 11, 12 and 15, the pair of coil end portions 38 of the short coil 32 are disposed along both axial end faces of the stator core 26 via the pair of axial end surface covering portions 28B of the insulator 28. The pair of coil end portions 38 of the long coil 34 are disposed along both axial end faces of the stator core 26 via the coil end portions 38 of the two short coils 32 adjacent in the circumferential direction and the pair of axial end surface covering portions 28B of the insulator 28. That is, the pair of coil end portions 38 of the long coil 34 are disposed so as to overlap in the axial direction with the pair of coil end portions 38 of the two short coils 32 adjacent in the circumferential direction. More specifically, in the state shown in Fig. 15, the pair of coil end portions 38 of the W-phase long coil 34 are disposed so as to overlap in the axial direction with the circumferentially one side portion of the pair of coil end portions 38 of the U-phase short coil 32 adjacent in the circumferential direction and the circumferentially other side portion of the pair of coil end portions 38 of the V-phase short coil 32. As shown in FIGS. 11 and 15, the coil end portions 38 of the other short coils 32 and the coil end portions 38 of the other long coils 34 are also arranged along both axial end faces of the stator core 26 in a similar relationship.

[0035] Next, the configuration of the main parts of this embodiment will be described.

[0036] FIG. 4 shows a cross section of the stator 14 cut along the radial direction. The radial thickness dimension of the stator core 26 constituting a part of the stator 14 is set to be larger than the radial dimension of the coil end portion 38 of the coil 16. In addition, a plurality of lightening holes 26B are formed as lightening portions in a portion of the stator core 26 opposite to the side where the opposing portion 36 of the coil 16 is arranged. That is, a plurality of lightening holes 26B are formed in the outer periphery of the stator core 26. The lightening holes 26B are formed so as to penetrate the outer periphery of the stator core 26 in the axial direction. The shape of the lightening holes 26B when viewed from the axial direction is circular. In addition, the plurality of lightening holes 26B are arranged at equal intervals along the circumferential direction.

[0037] Here, in this embodiment, the number of the lightening holes 26B is set to an integer multiple of a prime number that is not a prime factor of the number of magnetic poles of the magnets 18 of the rotor 12. To be more specific, in the configuration of the rotor 12 of this embodiment, the number of magnetic poles of the magnets 18 matches the number of the magnets 18. Therefore, the number of the lightening holes 26B is set to an integer multiple of a prime number that is not a prime factor of the number of the magnets 18 of the rotor 12.

[0038] As an example, consider a configuration in which the motor 10 of this embodiment has eight magnetic poles, i.e., a configuration having eight magnets 18. In this case, the prime factor of 8, which is the number of magnetic poles of the motor 10, is 2. Therefore, the prime numbers that are not prime factors are 3, 5, 7, 11, 13, 17, 19, etc. Furthermore, the integer multiples of these prime numbers that are not prime factors are 3, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, etc. Then, the number of lightening holes 26B is set to an integer multiple of these prime numbers that are not prime factors.

[0039] Next, consider a configuration in which the motor 10 of this embodiment has 10 magnetic poles, i.e., a configuration having 10 magnets 18. In this case, the prime factors of 10, which is the number of magnetic poles of the motor 10, are 2 and 5. Therefore, the prime numbers that are not prime factors are 3, 7, 11, 13, 17, 19, etc. Furthermore, the integer multiples of these prime numbers that are not prime factors are 3, 6, 7, 9, 11, 12, 13, 14, 15, etc. Then, the number of lightening holes 26B is set to an integer multiple of these prime numbers that are not prime factors.

[0040] Next, consider a configuration in which the motor 10 of this embodiment has 12 magnetic poles, i.e., a configuration having 12 magnets 18. In this case, the prime factors of 12, which is the number of magnetic poles of the motor 10, are 2 and 3. Therefore, the prime numbers that are not prime factors are 5, 7, 11, 13, 17, 19, etc. Furthermore, the integer multiples of these prime numbers that are not prime factors are 5, 7, 10, 11, 14, 15, 17, 19, etc. Then, the number of lightening holes 26B is set to an integer multiple of these prime numbers that are not prime factors.

[0041] Next, consider a configuration in which the motor 10 of this embodiment has 16 magnetic poles, i.e., a configuration having 16 magnets 18. In this case, the prime factor of 16, which is the number of magnetic poles of the motor 10, is 2. Therefore, the prime numbers that are not prime factors are 3, 5, 7, 11, 13, 17, 19, etc. Furthermore, the integer multiples of these prime numbers that are not prime factors are 3, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, etc. Then, the number of lightening holes 26B is set to an integer multiple of these prime numbers that are not prime factors.

[0042] Next, consider a configuration in which the motor 10 of this embodiment has 20 magnetic poles, i.e., a configuration having 20 magnets 18. In this case, the prime factors of 20, which is the number of magnetic poles of the motor 10, are 2 and 5. Therefore, the prime numbers that are not prime factors are 3, 7, 11, 13, 17, 19, etc. Furthermore, the integer multiples of these prime numbers that are not prime factors are 3, 6, 7, 9, 11, 12, 13, 14, 15, 17, 17, 18, 19, 21, etc. Then, the number of lightening holes 26B is set to an integer multiple of these prime numbers that are not prime factors.

[0043] As shown in FIG. 4, in the stator core 26 of this embodiment, the shape, size, number and arrangement of the multiple lightening holes 26B are set so that the maximum magnetic flux density inside the stator core 26 at the position of the multiple lightening holes 26B closest to the opposing portion 36 of the coil 16 is less than the saturation magnetic flux density of the material forming the stator core 26. In detail, first, an imaginary circle K circumscribed by the multiple lightening holes 26B is set when the stator core 26 is viewed from the axial direction. Next, the maximum magnetic flux density in a cylindrical cross section obtained by cutting the stator core 26 along the axial direction at a position corresponding to this imaginary circle K is considered. Then, the shape, size, number and arrangement of the multiple lightening holes 26B are set so that this maximum magnetic flux density is less than the saturation magnetic flux density of the material forming the stator core 26. In this embodiment, in order to prevent the entire stator core 26 including the magnet 18 side from being magnetically saturated, the maximum magnetic flux density is set to be 80% or less of the saturation magnetic flux density. Specifically, the maximum magnetic flux density is 1.44 T or less. In an outer rotor type motor configuration in which coil 16 is arranged on the outer periphery of stator core 26, when stator core 26 is viewed from the axial direction, an imaginary circle K is defined in which multiple lightening holes 26B are inscribed, and the maximum magnetic flux density is considered within a cylindrical cross section obtained by cutting stator core 26 along the axial direction at a position corresponding to this imaginary circle K.

[0044] In addition, in this embodiment, the shape, dimensions, number and arrangement of the multiple lightening holes 26B are set so that the volume of the portion of the stator core 26 that is outer circumferential of the imaginary circle K is larger than the volume of the multiple lightening holes 26B.

[0045] (Actions and Effects of the Present Embodiment) Next, the operation and effects of this embodiment will be described.

[0046] 3, 6, 7, 10, and 11, in the motor 10 of this embodiment, a rotating magnetic field is generated on the inner circumference of the stator 14 by switching the energization of the U-phase coil connection body 46U, the V-phase coil connection body 46V, and the W-phase coil connection body 46W that constitute a part of the stator 14. This causes the rotor 12 to rotate.

[0047] In the motor 10 of this embodiment, the number of long coils 34 and the number of short coils 32 in the coil connections 46U, 46V, 46W of each phase are set to be the same, so that the combined resistances of the coil connections 46U, 46V, 46W of each phase are the same. This makes it difficult for electrical imbalances to occur in the coil connections 46U, 46V, 46W of each phase. As a result, it is possible to suppress deterioration of the torque ripple of the motor 10.

[0048] Furthermore, in the motor 10 of this embodiment, the coil end portions 38 of the long coils 34 and the coil end portions 38 of the short coils 32 are configured to be bent at right angles radially outward relative to the opposing portions 36, and the coil end portions 38 of the long coils 34 and the coil end portions 38 of the short coils 32 are configured to be overlapped in the axial direction. This makes it possible to prevent the stator 14 from becoming large in size in the axial direction. As a result, it is possible to prevent the motor 10 from becoming large in size in the axial direction.

[0049] Furthermore, in the motor 10 of this embodiment, the cross-sectional shape of the winding 30 forming the coil 16 is a rectangle with the first direction (arrow A1 direction) as the longitudinal direction. In addition, the first direction of the winding 30 of the portion forming the opposing portion 36 of the short coil 32 and the opposing portion 36 of the long coil 34 is directed toward the magnet 18. This makes it possible to reduce the area of ​​the portion of the winding 30 facing the magnet 18 while ensuring the cross-sectional area of ​​the winding 30. This makes it possible to suppress an increase in the electrical resistance of the winding 30 while suppressing an increase in AC copper loss due to eddy currents generated in the opposing portion 36. In addition, in the motor 10 of this embodiment, the opposing portion 36 has a single-layer structure along the radially inner surface of the stator core 26. This makes it possible to easily form the shape of the opposing portion 36 as viewed from the axial direction into a curved shape corresponding to the radially inner surface of the stator core 26, as shown in FIG. 8. This makes it possible to improve the space factor.

[0050] 6, 7, 8 and 9, in the motor 10 of this embodiment, the portions (stacked windings 30) forming the pair of opposing portions 36, the coil end portion 38 on one axial side and the coil end portion 38 on the other axial side in the coil 16 are inseparably joined in the second direction in the manufacturing process of the coil 16. This improves the workability when bending the portions of the coil 16 forming the coil end portion 38 on one axial side and the coil end portion 38 on the other axial side at a substantially right angle radially outward.

[0051] Furthermore, in the motor 10 of this embodiment, the pair of terminal portions 40 are disposed on one axial side in a state in which the number of laminations of the winding 30 in the coil end portion 38 on one axial side of the coil 16 is smaller than the number of laminations of the winding 30 in the coil end portion 38 on the other axial side. With this configuration, the length of the portion of the coil 16 around which the winding 30 is wound can be shortened. This makes it possible to suppress an increase in the electrical resistance of the coil 16.

[0052] Furthermore, in the motor 10 of this embodiment, a plurality of circumferential positioning portions 28D are provided on the outer peripheral flange portion 28C of the insulator 28. This improves the workability when attaching the short coils 32 to the stator core 26 via the insulator 28. Also, the circumferential position of each of the short coils 32 can be stabilized, and each of the short coils 32 can be arranged more evenly in the circumferential direction. Note that a configuration may be adopted in which only the circumferential positioning portions 28D for positioning the short coils 32 of one phase in the circumferential direction are provided.

[0053] 2 and 4, in the motor 10 of this embodiment, the core engagement portion 28J of the insulator 28 is adapted to engage with the lightening hole 26B of the stator core 26. This makes it possible to restrict circumferential displacement of the insulator 28 relative to the stator core 26. Note that the core engagement portion 28J may be provided at one location in the circumferential direction, or at multiple locations in the circumferential direction.

[0054] Furthermore, in the motor 10 of the present embodiment, a plurality of lightening holes 26B are formed in the outer periphery of the stator core 26. This makes it possible to reduce the weight of the stator core 26. As a result, the weight of the motor 10 can be reduced.

[0055] Furthermore, in the motor 10 of this embodiment, the number of the lightening holes 26B formed in the stator core 26 is set to an integer multiple of a prime number that is not a prime factor of the number of magnetic poles of the magnet 18 of the rotor 12. This makes it possible to increase the order of the cogging torque of the motor 10. As a result, it is possible to reduce the amplitude of the cogging torque of the motor 10, thereby enabling the motor 10 to achieve low noise and low vibration.

[0056] Furthermore, in the stator core 26 of the motor 10 of this embodiment, the shape, size, number and arrangement of the multiple lightening holes 26B are set so that the maximum magnetic flux density inside the stator core 26 at the position of the multiple lightening holes 26B closest to the opposing portion 36 of the coil 16 is less than the saturation magnetic flux density of the material forming the stator core 26. This makes it difficult for the entire stator core 26, including the magnet 18 side, to become magnetically saturated, making it possible to suppress a decrease in the torque of the motor 10.

[0057] In this embodiment, the shape, size, number and arrangement of the plurality of lightening holes 26B are set so that the volume of the portion of the stator core 26 that is on the outer circumferential side of the imaginary circle K is larger than the volume of the plurality of lightening holes 26B. This makes it possible to prevent the heat dissipation path from the stator core 24 side to the housing 74 (see FIG. 2) side from narrowing. In other words, it is possible to prevent an increase in heat transfer resistance from the stator core 24 side to the housing 74 side.

[0058] Here, in a configuration in which the number of lightening holes 26B formed in the stator core 26 is fixed, the number of magnetic poles of the magnet 18 is set to an integer multiple of a prime number that is not a prime factor of the number of lightening holes 26B. This provides the same effect as when the number of lightening holes 26B formed in the stator core 26 is set to an integer multiple of a prime number that is not a prime factor of the number of magnetic poles of the magnet 18 of the rotor 12, as described above.

[0059] For example, consider a configuration in which the number of the lightening holes 26B is determined to be eight. In this case, the prime factor of 8, which is the number of the lightening holes 26B, is 2. Therefore, the prime numbers that are not prime factors are 3, 5, 7, 11, 13, 17, 19... Furthermore, the integer multiples of these prime numbers that are not prime factors are 3, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15... Then, the number of magnets 18 is set to an integer multiple of these prime numbers that are not prime factors. Here, the number of magnets 18 is set to be an even number. Therefore, the number of magnets 18 is set to 6, 10, 12, 14..., which are integer multiples of the above prime numbers that are not prime factors and are even numbers.

[0060] Next, consider a configuration in which the number of lightening holes 26B is determined to be nine. In this case, the prime factor of 9, which is the number of lightening holes 26B, is 3. Therefore, the prime numbers that are not prime factors are 2, 5, 7, 11, 13, 17, 19.... Furthermore, the integer multiples of these prime numbers that are not prime factors are 2, 4, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15, 16.... Then, the number of magnets 18 is set to 2, 4, 6, 8, 10, 12, 14, 16..., which are integer multiples of these prime numbers that are not prime factors and are even numbers.

[0061] Next, consider a configuration in which the number of lightening holes 26B is determined to be 10. In this case, the prime factors of 10, which is the number of lightening holes 26B, are 2 and 5. Therefore, the prime numbers that are not prime factors are 3, 7, 11, 13, 17, 19, etc. Furthermore, the integer multiples of these prime numbers that are not prime factors are 3, 6, 7, 9, 11, 12, 12, 13, 14, 15, etc. Then, the number of magnets 18 is set to 6, 12, 14, etc., which are integer multiples of these prime numbers that are not prime factors and are even numbers.

[0062] Next, consider a configuration in which the number of lightening holes 26B is determined to be 12. In this case, the prime factors of 12, which is the number of lightening holes 26B, are 2 and 3. Therefore, the prime numbers that are not prime factors are 5, 7, 11, 13, 17, 19.... Furthermore, the integer multiples of these prime numbers that are not prime factors are 5, 7, 10, 11, 14, 15, 17, 19, 20, 21, 22.... Then, the number of magnets 18 is set to 10, 14, 20, 22..., which are integer multiples of these prime numbers that are not prime factors and are even numbers.

[0063] Next, consider a configuration in which the number of lightening holes 26B is determined to be 21. In this case, the prime factors of 21, which is the number of lightening holes 26B, are 3 and 7. Therefore, the prime numbers that are not prime factors are 2, 5, 11, 13, 17, 19.... Furthermore, the integer multiples of these prime numbers that are not prime factors are 2, 4, 5, 6, 8, 10, 11, 12, 13, 14, 15, 16.... Then, the number of magnets 18 is set to integer multiples of these prime numbers that are not prime factors and are even numbers, 2, 4, 6, 8, 10, 12, 14, 16....

[0064] (Motors of the Second to Nineteenth Embodiments) Next, configurations of motors according to the second to nineteenth embodiments, which can achieve weight reduction similar to the motor 10 of the first embodiment, will be described with reference to Figures 16 to 35. Note that members and parts of the motors according to the second to nineteenth embodiments that correspond to those of the motors of the embodiments already described will be given the same reference numerals as those of the motors of the embodiments already described, and descriptions thereof may be omitted.

[0065] (Motor of the second embodiment) As shown in FIG. 16, in the motor 90 of the second embodiment, a plurality of lightening grooves 26C are formed in the outer periphery of the stator core 26 as lightening portions. The lightening grooves 26C are formed in a groove shape that is open on the radially outer side and is formed along the axial direction. The lightening grooves 26C are formed continuously from one end of the outer periphery of the stator core 26 in the axial direction to the other end. The edge shape of the lightening grooves 26C when viewed from the axial direction is U-shaped. The plurality of lightening grooves 26C are arranged at equal intervals along the circumferential direction. The number of the lightening grooves 26C is set to an integer multiple of a prime number that is not a prime factor of the number of magnetic poles of the magnet 18 of the rotor 12. The motor 90 of the second embodiment can also be made lighter, as in the motor 10 of the first embodiment.

[0066] (Motor of the third embodiment) As shown in FIG. 17, the stator core 26 constituting a part of the motor of the third embodiment is formed by stacking core forming members 92 spirally formed along the axial direction in the axial direction. A plurality of hollow portion forming portions 92A with the radially outer side open are formed on the outer periphery of the core forming member 92. When the core forming members 92 are stacked in the axial direction, the circumferential position of the hollow portion forming portion 92A of one layer and the circumferential position of the hollow portion forming portion 92A of the other layer are arranged at the same position. As a result, when the core forming members 92 are stacked in the axial direction, the plurality of hollow portion forming portions 92A form the hollow portion grooves 26C. The motor of the third embodiment can also be made lighter in weight, as in the motor 10 of the first embodiment. The number and positions of the hollow portion forming portions 92A may be set so that a plurality of hollow portion grooves 26C are formed.

[0067] (Motor of the fourth embodiment) As shown in FIG. 18, in the motor 94 of the fourth embodiment, a filler 96 is disposed inside a plurality of the lightening holes 26B formed in the stator core 26. The filler 96 is formed of a material lighter than the stator core 26. As an example, the filler 96 is formed of a resin material, a material in which glass fiber or the like is mixed into a resin material, aluminum, or the like. The filler 96 may be poured into the lightening holes 26B in a molten state. The filler 96 may be formed in a rod shape and pressed into the lightening holes 26B. In this embodiment, the filler 96 is not disposed in the lightening holes 26B with which the core engaging portion 28J of the insulator 28 engages. The motor 94 of the fourth embodiment can also be made lighter in weight, as in the motor 10 of the first embodiment. The filler 96 is formed of a material having a higher thermal conductivity than the stator core 26, thereby improving the heat dissipation of the motor 94.

[0068] (Motor of the fifth embodiment) 19 and 20, in the stator core 26 of the motor of the fifth embodiment, a plurality of lightening grooves 26C are formed on both axial sides of the outer periphery of the stator core 26. That is, in the stator core 26 of the motor of the fifth embodiment, a plurality of lightening grooves 26C are not formed in the axial center of the outer periphery of the stator core 26. In the motor of the fifth embodiment, too, it is possible to achieve weight reduction, similar to the motor 10 of the first embodiment.

[0069] (Motor of the sixth embodiment) As shown in FIG. 21, in the stator core 26 of the motor of the sixth embodiment, the intervals between the circumferentially adjacent lightening grooves 26C are set to be unequal in a portion of the stator core 26. More specifically, in the stator core 26 of the motor of the sixth embodiment, the intervals between the circumferentially adjacent lightening grooves 26C are set to θ in most of the outer periphery of the stator core 26. In addition, in a portion of the stator core 26 shown in FIG. 21, the intervals between the circumferentially adjacent lightening grooves 26C are set to θ+α or θ-α. In the motor of the sixth embodiment, the weight can be reduced as in the motor 10 of the first embodiment. In addition, by setting the intervals between the circumferentially adjacent lightening grooves 26C to be unequal in a portion of the stator core 26, the cogging torque characteristics of the motor can be adjusted. Note that the intervals between the circumferentially adjacent lightening grooves 26C may be set to be unequal in a plurality of portions of the stator core 26.

[0070] (Motor of the seventh embodiment) As shown in FIG. 22, in the stator core 26 of the motor of the seventh embodiment, the circumferential width of the lightening groove 26C is set to be non-uniform in a part of the stator core 26. That is, in the stator core 26 of the motor of the seventh embodiment, the volume in the lightening groove 26C is set to be non-uniform in a part of the stator core 26. To be more specific, in the stator core 26 of the motor of the seventh embodiment, the circumferential width of the lightening groove 26C is set to W in most of the outer periphery of the stator core 26. In addition, in a part of the stator core 26 shown in FIG. 22, the circumferential width of the lightening groove 26C is set to W+α or W-α. In the motor of the seventh embodiment, the weight can be reduced like the motor 10 of the first embodiment. In addition, by setting the circumferential width of the lightening groove 26C to be non-uniform in a part of the stator core 26, the cogging torque characteristic of the motor can be adjusted. The circumferential width of the lightening grooves 26C may be set to be uneven at multiple locations on the stator core 26.

[0071] (Motor of Eighth Embodiment) As shown in Fig. 23, the stator core 26 of the motor of the eighth embodiment has a structure divided into two parts in the circumferential direction. The stator core 26 of the motor of the eighth embodiment is formed by stacking core forming members formed in a plate shape in the axial direction. The configuration in which the core forming members are stacked in the axial direction will be described in detail in the embodiments described later.

[0072] 24 shows an enlarged view of a portion of the stator core 26 of the motor of the eighth embodiment. As shown in this figure, the stator core 26 is a powder core formed by compressing magnetic particles 98 having insulating coatings 98A on their surfaces. The motor of the eighth embodiment can also be made lighter, similar to the motor 10 of the first embodiment.

[0073] (Motors of the 9th to 11th embodiments) As shown in Fig. 25, Fig. 26 and Fig. 27, the stator core 26 of the motor of the ninth to eleventh embodiments is formed by stacking core forming members 92 formed in an annular shape in the axial direction. In Fig. 25, Fig. 26 and Fig. 27, the core forming member 92 is illustrated in a part of the stator core 26. A plurality of hollow portion forming portions 92A, which are open on the radially outer side, are formed on the outer periphery of the core forming member 92. The plurality of hollow portion forming portions 92A are arranged at equal intervals along the circumferential direction. When the core forming members 92 are stacked in the axial direction, the circumferential position of the hollow portion forming portion 92A of one layer and the circumferential position of the hollow portion forming portion 92A of the other layer are arranged in the same position. As a result, when the core forming members 92 are stacked in the axial direction, a plurality of hollow portion forming portions 92A form a plurality of hollow grooves 26C.

[0074] As shown in FIG. 25, in the stator core 26 of the motor of the ninth embodiment, the laminated core forming members 92 are integrated in the axial direction by crimping the portions of the laminated core forming members 92 where the lightening portion forming portion 92A is not formed with the crimping portion 100. As shown in FIG. 26, in the stator core 26 of the motor of the tenth embodiment, the laminated core forming members 92 are integrated in the axial direction by laser welding the portions of the laminated core forming members 92 where the lightening portion forming portion 92A is not formed along the axial direction. The laser welded portions are indicated by reference numeral 102. As shown in FIG. 27, in the stator core 26 of the motor of the eleventh embodiment, the laminated core forming members 92 are integrated in the axial direction by laser welding the portions of the laminated core forming members 92 corresponding to the lightening portion forming portion 92A along the axial direction or applying an adhesive. The laser welded portions or applying an adhesive are indicated by reference numeral 104. Alternatively, the laminated core forming members 92 may be integrated in the axial direction by adhesive provided between the layers of the laminated core forming members 92 .

[0075] The motors of the ninth to eleventh embodiments described above can also be made lighter in weight, similar to the motor 10 of the first embodiment. Here, in the stator core 26 shown in Fig. 25 and Fig. 26, the laminated core forming members 92 are integrated in the axial direction by performing machining on the outer circumferential side of the imaginary circle K. In this configuration, the influence of the deterioration of the magnetic characteristics caused by machining can be reduced, and the decrease in torque of the motor 10 and the increase in cogging torque can be suppressed.

[0076] (Motors of the 12th to 18th embodiments) As shown in Figures 28 to 34, the stator core 26 of the motors of the twelfth to eighteenth embodiments is formed by stacking core forming members 92 in the axial direction. A hollow portion forming portion 92A is formed on the outer periphery of this core forming member 92. Note that Figures 28 to 34 show a part of a cross section cut by a cylindrical surface that passes through the center of the hollow hole 26B and is concentric with the rotation axis. This configuration can also be applied to the hollow groove 26C.

[0077] 28, in the stator core 26 of the motor of the twelfth embodiment, the dimensions of the cutout portion forming portions 92A of each layer are set to be the same. In this stator core 26, the stacked core forming members 92 are integrated in the axial direction with the cutout portion forming portions 92A of each layer being positioned in the same circumferential position.

[0078] 29, in the stator core 26 of the motor of the thirteenth embodiment, the dimensions of the cutout portion forming portions 92A of each layer are set to be the same. In this stator core 26, the stacked core forming members 92 are integrated in the axial direction with the circumferential positions of the cutout portion forming portions 92A of each layer being shifted at unequal pitches in the circumferential direction.

[0079] 30, in the stator core 26 of the motor of the fourteenth embodiment, the dimensions of the cutout portion forming portions 92A of each layer are set to be different from each other. Also, in this stator core 26, the stacked core forming members 92 are integrated in the axial direction with the circumferential positions of the cutout portion forming portions 92A of each layer being shifted at unequal pitches in the circumferential direction.

[0080] 31, in the stator core 26 of the motor of the fifteenth embodiment, the dimensions of the cutout portion forming portions 92A of each layer are set to be the same. Also, in this stator core 26, the stacked core forming members 92 are integrated in the axial direction with the circumferential positions of the cutout portion forming portions 92A of each layer shifted in the circumferential direction so that the cutout holes 26B are inclined toward one circumferential side as they move from one axial side to the other side.

[0081] 32, in the stator core 26 of the motor of the sixteenth embodiment, the dimensions of the cutout portion forming portions 92A of each layer are set to be the same. Also, in this stator core 26, the stacked core forming members 92 are integrated in the axial direction with the circumferential positions of the cutout portion forming portions 92A of each layer shifted in the circumferential direction so that the cutout holes 26B are stepped from one axial side to the other.

[0082] 33, in the stator core 26 of the motor of the seventeenth embodiment, the dimensions of the cutout portion forming portions 92A of each layer are set to be the same. Also, in this stator core 26, the stacked core forming members 92 are integrated in the axial direction with the circumferential positions of the cutout portion forming portions 92A of each layer shifted in the circumferential direction so that the cutout holes 26B are interrupted in the axial direction.

[0083] 34, in the stator core 26 of the motor of the eighteenth embodiment, the dimensions of the cutout portion forming portions 92A of each layer are set to be the same. Also, in this stator core 26, the stacked core forming members 92 are integrated in the axial direction with the circumferential positions of the cutout portion forming portions 92A of each layer shifted in the circumferential direction so that the cutout holes 26B are interrupted in the axial direction for each layer.

[0084] The motors of the twelfth to eighteenth embodiments described above can also be made lighter, like the motor 10 of the first embodiment. Furthermore, by appropriately changing the settings of the circumferential position and circumferential width of the cutout portion forming portion 92A of each layer, the cogging torque characteristics of the motor can be adjusted.

[0085] (Motor of 19th embodiment) 35, in the insulator 28 of the motor of the 19th embodiment, the core engagement portion 28J is formed into a shape that narrows toward the tip side in the protruding direction. This makes it possible to improve the workability when engaging the core engagement portion 28J of the insulator 28 with the lightening groove 26C of the stator core 26 in the motor of the 19th embodiment.

[0086] (Motor of 20th embodiment) As shown in Fig. 36 and Fig. 37, the insulator 28 of the motor of the twentieth embodiment includes a plurality of first circumferential positioning parts 28E as circumferential positioning parts for positioning the short coil 32 in the circumferential direction, and a plurality of second circumferential positioning parts 28F as circumferential positioning parts for positioning the medium coil 48 in the circumferential direction. Here, the medium coil 48 refers to the coil 16 whose axial dimension is set to be larger than the axial dimension of the short coil 32 and smaller than the axial dimension of the long coil 34. The configurations of the first circumferential positioning parts 28E and the second circumferential positioning parts 28F are similar to those of the above-mentioned circumferential positioning part 28D (see Fig. 13). The plurality of first circumferential positioning parts 28E are arranged at equal intervals in the circumferential direction along the shaft end surface covering part 28B. The plurality of second circumferential positioning parts 28F are arranged at equal intervals in the circumferential direction at positions offset to one side in the axial direction with respect to the plurality of first circumferential positioning parts 28E. Furthermore, when viewed from one axial side, the multiple second circumferential positioning portions 28F are each disposed between a pair of first circumferential positioning portions 28E adjacent to each other in the circumferential direction.

[0087] The coil end portion 38 of the short coil 32 is disposed between a pair of circumferentially adjacent first circumferential positioning portions 28E, so that the short coil 32 is positioned in the circumferential direction. The coil end portion 38 of the middle coil 48 is disposed between a pair of circumferentially adjacent second circumferential positioning portions 28F, so that the middle coil 48 is positioned in the circumferential direction. Here, when the coil end portion 38 of the middle coil 48 is disposed between a pair of circumferentially adjacent second circumferential positioning portions 28F, the coil end portion 38 of the middle coil 48 abuts against the axial end surface of the first circumferential positioning portion 28E. This allows the middle coil 48 to be positioned in the axial direction. That is, the first circumferential positioning portion 28E serves as the first axial positioning portion 28G, which serves as an axial positioning portion that positions the middle coil 48 in the axial direction. Furthermore, when the long coil 34 is arranged along the stator core 26 via the insulator 28, the coil end portion 38 of the long coil 34 abuts against the axial end face of the second circumferential positioning portion 28F. This allows the long coil 34 to be positioned in the axial direction. In other words, the second circumferential positioning portion 28F serves as the second axial positioning portion 28H that serves as an axial positioning portion that positions the long coil 34 in the axial direction.

[0088] In the motor of this embodiment described above, by providing the first circumferential positioning portion 28E (first axial positioning portion 28G) and the second circumferential positioning portion 28F (second axial positioning portion 28H), it is possible to improve workability when attaching each coil 16 to the stator core 26 via the insulator 28.

[0089] (Motor of 21st embodiment) As shown in Fig. 38, the motor 54 of the twenty-first embodiment is characterized in that the stator core 26 is provided with small projections 26A as inter-winding portions disposed between a pair of opposing portions 36 adjacent in the circumferential direction. Here, the circumferential width of the small projections 26A is Wt, the saturation magnetic flux density of the small projections 26A is Bs, the circumferential width of one magnetic pole of the magnet 18 is Wm, and the residual magnetic flux density of the magnetic compound forming the magnet 18 is Br. The small projections 26A are formed using a magnetic material or a non-magnetic material that satisfies the relationship Wt x Bs ≤ Wm x Br. This can improve the magnetic flux density of the stator 14 and suppress magnetic saturation and magnetic flux leakage, thereby improving the torque of the motor 54.

[0090] (Motor of 22nd embodiment) As shown in Fig. 39, in the motor 56 of the twenty-second embodiment, the magnet 18 of the rotor 12 is formed using a magnetic compound having an intrinsic coercivity Hc of 400 [kA / m] or more and a residual magnetic flux density Br of 1.0 [T] or more. When the magnet 18 is viewed from the axial direction, the angle between the direction of the magnetization easy axis 58 at the magnetic pole center of the magnet 18 and the radial direction (d-axis 60) is set to be smaller than the angle between the direction of the magnetization easy axis 58 between the magnetic poles of the magnet 18 and the radial direction (q-axis 62). This makes it possible to increase the magnetic flux density in the air gap with the stator 14. As a result, it is possible to reduce the size and power of the motor 56 and reduce the amount of magnets 18.

[0091] (Motor of the 23rd embodiment, Motor of the 24th embodiment) 40A, in a motor 64 of the twenty-third embodiment, a portion of one circumferentially adjacent magnet 18 facing the coil 16 and a portion of the other circumferentially adjacent magnet 18 facing the coil 16 are spaced apart in the circumferential direction. Also, an intervening portion 24D formed using a magnetic material is interposed between a portion of one circumferentially adjacent magnet 18 facing the coil 16 and a portion of the other circumferentially adjacent magnet 18 facing the coil 16. The intervening portion 24D is formed integrally with the rotor core 24, for example.

[0092] 40B, in a motor 66 of the twenty-fourth embodiment, a portion of one circumferentially adjacent magnet 18 facing the coil 16 and a portion of the other circumferentially adjacent magnet 18 facing the coil 16 are circumferentially spaced apart. Also, a portion of one circumferentially adjacent magnet 18 facing the opposite side to the coil 16 and a portion of the other circumferentially adjacent magnet 18 facing the opposite side to the coil 16 are in contact with each other or are slightly spaced apart from each other in the circumferential direction.

[0093] In the motor 64 of the twenty-third embodiment and the motor 66 of the twenty-fourth embodiment configured as described above, the magnetic resistance between the magnets 18 adjacent to each other in the circumferential direction can be reduced and the magnetic flux density can be increased.

[0094] (Motor of the 25th embodiment) As shown in FIG. 41, the motor 68 of the twenty-fifth embodiment is a motor with a reducer 70. Most of the reducer 70 is disposed inside the rotor core 24. The reducer 70 includes an internal gear 72 fixed to the rotating shaft 22, and an external gear 76 disposed radially outside the internal gear 72 and fixed to a housing 74 supporting the stator 14. The reducer 70 also includes a planetary gear 78 disposed between the internal gear 72 and the external gear 76 and meshing with the internal gear 72 and the external gear 76, a carrier 80 supporting the planetary gear 78, and an output shaft 82 fixed to the carrier 80. In the motor 68 with this configuration, the rotation of the rotor 12 can be reduced in speed by the reducer 70 and transmitted to the output shaft 82.

[0095] (Motor of the 26th embodiment and the 27th embodiment) 42 and 43, a motor 84 of the 26th embodiment and a motor 86 of the 27th embodiment are formed using the same short coils 32 and long coils 34. In this case, by adjusting the circumferential length of the stator core 26, etc., it is possible to manufacture a plurality of types of motors 84, 86 with different outputs and sizes using the same short coils 32 and long coils 34.

[0096] The configurations of the motor 10 and the like in each of the embodiments described above can be combined with each other. This combination can be set appropriately taking into consideration the output and size required of the motor. Furthermore, the configurations of the motor 10 and the like in each of the embodiments described above can be applied not only to inner rotor type motors but also to outer rotor type motors.

[0097] In the above-described example, the pair of coil end portions 38 of the coil 16 are bent at approximately right angles toward the axial end face of the stator core 26, but the present invention is not limited to this. For example, in the example shown in Fig. 44, the coil end portion 38 on one axial side of the short coil 32 is bent at approximately right angles toward the axial end face of the stator core 26, and the coil end portion 38 on the other axial side is bent at approximately right angles toward the opposite side of the stator core 26. In addition, the coil end portion 38 on one axial side of the long coil 34 is bent at approximately right angles toward the axial end face of the stator core 26, and the coil end portion 38 on the other axial side is bent at approximately right angles toward the opposite side of the stator core 26. In the example shown in Fig. 45, the coil end portion 38 on one axial side of the short coil 32 is bent at approximately right angles toward the axial end face of the stator core 26, and the coil end portion 38 on the other axial side is not bent. Also, the coil end portion 38 on one axial side of the long coil 34 is not bent, and the coil end portion 38 on the other axial side is bent at a substantially right angle toward the opposite side of the stator core 26. In this example, the terminal portion 40 of the coil 16 is inclined with respect to the axial direction. Also, in the example shown in FIG. 46, the pair of coil end portions 38 of the short coil 32 is bent at a substantially right angle toward the axial end face side of the stator core 26, and the pair of coil end portions 38 of the long coil 34 is not bent. Furthermore, in the example shown in FIG. 47, the pair of coil end portions 38 of the short coil 32 is bent toward the axial end face side of the stator core 26 so as to be inclined with respect to the axial direction, and the pair of coil end portions 38 of the long coil 34 is bent toward the axial end face side of the stator core 26 so as to be inclined with respect to the axial direction. In this way, whether or not the pair of coil end portions 38 of the coil 16 are bent, and the bending direction and bending angle may be appropriately set in consideration of the physical size required for the motor, etc. 48, it is preferable that the end portion on one axial side and the end portion on the other axial side of the magnet 18 are arranged radially opposite the coil end portion 38 on one axial side and the coil end portion 38 on the other axial side, respectively. This makes it possible to increase the output of the motor and to make it more compact.

[0098] Also, as shown in Fig. 49, the winding 30 forming the coil 16 may be configured with two winding configurations 88 stacked in the second direction (arrow A2 direction). Furthermore, as shown in Fig. 50, the winding 30 forming the coil 16 may be configured with two winding configurations 88 stacked in the first direction (arrow A1 direction). Also, as shown in Fig. 51, the winding 30 forming the coil 16 may be configured with four winding configurations 88 stacked in the first and second directions.

[0099] In each of the above-described embodiments, the configuration has been described in which the side on which the magnet 18 is provided is the rotor 12, and the side on which the coil 16 is provided is the stator 14, but the configuration of the present disclosure can also be applied to a configuration in which the side on which the coil 16 is provided is the rotor 12, and the side on which the magnet 18 is provided is the stator 14. Needless to say, the configuration of the present disclosure can also be applied to a generator in which the rotor is rotated by an external force.

[0100] While one embodiment of the present disclosure has been described above, the present disclosure is not limited to the above, and it goes without saying that the present disclosure can be implemented in various other modified forms without departing from the spirit and scope of the present disclosure. [Explanation of symbols]

[0101] 10 motor, 12 rotor (rotating body), 16 coil, 18 magnet, 26 stator core (core), 28 insulator, 28D circumferential positioning portion, 28E first circumferential positioning portion (circumferential positioning portion), 28F second circumferential positioning portion (circumferential positioning portion), 28G first axial positioning portion (axial positioning portion), 28H second axial positioning portion (axial positioning portion), 28J core engagement portion, 28K radial outer flange portion (axial reference portion), 28L cutout portion (circumferential reference portion), 26B lightening hole (lightening portion), 26C lightening groove (lightening portion), 30 winding, 36 opposing portion, 38 coil end portion, 54 motor, 56 motor, 64 motor, 66 motor, 68 motor, 74 housing (core support member), 84 motor, 86 motor, 90 motor, 92 Core forming member, 92A hollow portion forming portion, 94 motor, 96 filling material, K virtual circle

Claims

1. A rotor (12) having a magnet (18) and supported rotatably; a plurality of coils (16) arranged in a ring shape in the circumferential direction, each of which is formed by winding a conductive winding (30) in a ring shape, with a portion of the winding being arranged in a line in the circumferential direction to form an opposing portion (36) arranged radially opposite the axial center of the magnet, and coil end portions (38) each forming a portion on one side and the other side in the axial direction with respect to the opposing portion; a core (26) formed in an annular shape, the opposing portions of the coils being arranged along an inner peripheral surface or an outer peripheral surface, at least one of the coil end portions on one axial side of the coils and the coil end portion on the other axial side of the coils being arranged along an end face in the axial direction, and a lightening portion (26B, 26C) being formed in a portion opposite to the opposing portions, the shape, size, number and arrangement of the hollowed-out portions are set so that a maximum magnetic flux density inside the core at a position in the hollowed-out portion closest to the opposing portion is less than a saturation magnetic flux density of a material forming the core, The core is formed by stacking, in the axial direction, plate-shaped core forming members (92) each having a hollow portion forming portion (92A) that forms the hollow portion, When the core is viewed from the axial direction, a virtual circle is defined in which the hollowed-out portion is circumscribed or inscribed on the opposite side to the facing portion, A motor (10, 54, 56, 64, 66, 68, 84, 86, 90, 94) in which the core forming member is machined at a portion of the core opposite the opposing portion from the imaginary circle, and the core forming member is integrated in an axially stacked state.

2. The core has a plurality of the hollowed-out portions formed at intervals in a circumferential direction, 2. The motor according to claim 1, wherein the number of the hollowed-out portions is set to an integer multiple of a prime number that is not a prime factor of the number of magnetic poles of the magnet.

3. The core has a plurality of the hollowed-out portions formed at intervals in a circumferential direction, 2. The motor according to claim 1, wherein the number of magnetic poles of the magnet is set to an integer multiple of a prime number that is not a prime factor of the number of the hollowed-out portions.

4. 4. The motor according to claim 2, wherein the intervals between adjacent circumferentially adjacent recesses are set to be equal over the entire circumference of the core.

5. 4. The motor according to claim 2, wherein the intervals between adjacent said hollowed-out portions in the circumferential direction are set to be unequal intervals in at least a portion of said core.

6. 4. The motor according to claim 2, wherein the volumes of the plurality of hollowed-out portions are set unevenly in at least a portion of the core.

7. The motor according to any one of claims 1 to 6, wherein a filler (96) made of a material lighter than the core is disposed inside the hollowed-out portion.

8. An insulator (28) is attached to the core to separate the core from the coil, A motor as described in any one of claims 1 to 7, wherein the insulator is provided with a core engagement portion (28J) that engages with the hollowed-out portion to restrict circumferential displacement of the insulator relative to the core.

9. A rotor (12) having a magnet (18) and rotatably supported thereon; a plurality of coils (16) arranged in a ring shape in the circumferential direction, each of which is formed by winding a conductive winding (30) in a ring shape, with a portion of the winding being arranged in a line in the circumferential direction to form an opposing portion (36) arranged radially opposite the axial center of the magnet, and coil end portions (38) each forming a portion on one side and the other side in the axial direction with respect to the opposing portion; a core (26) formed in an annular shape, the opposing portions of the coils being arranged along an inner peripheral surface or an outer peripheral surface, at least one of the coil end portions on one axial side of the coils and the coil end portion on the other axial side of the coils being arranged along an end face in the axial direction, and a lightening portion (26B, 26C) being formed in a portion opposite to the opposing portions, the shape, size, number and arrangement of the hollowed-out portions are set so that a maximum magnetic flux density inside the core at a position in the hollowed-out portion closest to the opposing portion is less than a saturation magnetic flux density of a material forming the core, An insulator (28) is attached to the core to separate the core from the coil, the insulator is provided with a core engaging portion (28J) that engages with the hollowed portion to restrict circumferential displacement of the insulator relative to the core, The motor has circumferential positioning portions (28D, 28E, 28F) on the insulator for positioning the coil in the circumferential direction.

10. A rotor (12) having a magnet (18) and rotatably supported thereon; a plurality of coils (16) arranged in a ring shape in the circumferential direction, each of which is formed by winding a conductive winding (30) in a ring shape, with a portion of the winding being arranged in a line in the circumferential direction to form an opposing portion (36) arranged radially opposite the axial center of the magnet, and coil end portions (38) each forming a portion on one side and the other side in the axial direction with respect to the opposing portion; a core (26) formed in an annular shape, the opposing portions of the coils being arranged along an inner peripheral surface or an outer peripheral surface, at least one of the coil end portions on one axial side of the coils and the coil end portion on the other axial side of the coils being arranged along an end face in the axial direction, and a lightening portion (26B, 26C) being formed in a portion opposite to the opposing portions, the shape, size, number and arrangement of the hollowed-out portions are set so that a maximum magnetic flux density inside the core at a position in the hollowed-out portion closest to the opposing portion is less than a saturation magnetic flux density of a material forming the core, An insulator (28) is attached to the core to separate the core from the coil, the insulator is provided with a core engaging portion (28J) that engages with the hollowed portion to restrict circumferential displacement of the insulator relative to the core, The motor has an axial positioning portion (28G, 28H) on the insulator for positioning the coil in the axial direction.

11. The core engagement portion is formed in a convex shape, The motor according to any one of claims 8 to 10, wherein the core engaging portion is formed into a shape that narrows toward a tip end in a protruding direction.

12. A rotor (12) having a magnet (18) and rotatably supported thereon; a plurality of coils (16) arranged in a ring shape in the circumferential direction, each of which is formed by winding a conductive winding (30) in a ring shape, with a portion of the winding being arranged in a line in the circumferential direction to form an opposing portion (36) arranged radially opposite the axial center of the magnet, and coil end portions (38) each forming a portion on one side and the other side in the axial direction with respect to the opposing portion; a core (26) formed in an annular shape, the opposing portions of the coils being arranged along an inner peripheral surface or an outer peripheral surface, at least one of the coil end portions on one axial side of the coils and the coil end portion on the other axial side of the coils being arranged along an end face in the axial direction, and a lightening portion (26B, 26C) being formed in a portion opposite to the opposing portions, the shape, size, number and arrangement of the hollowed-out portions are set so that a maximum magnetic flux density inside the core at a position in the hollowed-out portion closest to the opposing portion is less than a saturation magnetic flux density of a material forming the core, An insulator (28) is attached to the core to separate the core from the coil, the insulator is provided with a core engaging portion (28J) that engages with the hollowed portion to restrict circumferential displacement of the insulator relative to the core, The core is supported by a core support member (74), the insulator includes an axial reference portion (28K) protruding toward an opposite side to the rotor from a surface of the core opposite to the rotor, The motor has an axial position of the core relative to the core support member determined by the axial reference portion abutting against the core support member.

13. The insulator includes a circumferential reference portion (28L), The motor according to claim 12 , wherein the circumferential reference portion engages with a core support member, thereby positioning the core in the circumferential direction relative to the core support member.

14. When the core is viewed from the axial direction, a virtual circle is defined in which the hollowed-out portion is circumscribed or inscribed on the opposite side to the facing portion, The motor according to any one of claims 1 to 13, wherein a volume of a portion of the core opposite the opposing portion from the imaginary circle is set to be larger than a volume of the hollowed-out portion.

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