Rotating Electric Machine

Abstract

To provide a motor that can improve the durability of connecting parts and also reduce the weight of a rotary electric machine.SOLUTION: A rotary electric machine includes a rotor core which is a laminated body consisting of a plurality of electromagnetic steel plates 60 stacked on top of each other. In the electromagnetic steel plates, a plurality of through-holes 72 are formed between an inner ring portion 62 and an outer ring portion 64. The inner ring portion and outer ring portion, which are separated by through-holes, are connected to each other by a plurality of connecting portions 66. An intersection angle (β) between one connecting part and another connecting part adjacent to the connecting part is within a range of 12° to 36°.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a rotating electric machine including a stator and a rotor. [Background technology]

[0002] The rotating electric machine includes a stator and a rotor. The stator has a plurality of teeth. Slots are formed between adjacent teeth. An electromagnetic coil is provided in the slot. Meanwhile, the rotor has a permanent magnet.

[0003] A rotating electric machine functions as, for example, a motor. In this case, electricity is passed through an electromagnetic coil. When electricity is passed through the electromagnetic coil, it becomes magnetized and an alternating magnetic field is generated. This alternating magnetic field and the magnetic field generated by the permanent magnet repel each other. Alternatively, the two magnetic fields attract each other. This repulsion and attraction causes the rotor to rotate.

[0004] A motor, for example, applies a rotational driving force to a rotating body. When the rotating body is a propeller of an aircraft, the motor is required to have a performance capable of continuously outputting a high torque at a low rotation speed when the aircraft takes off or hovering. In order to obtain this performance, it is conceivable to make the motor larger. However, in this case, the weight of the motor becomes large. Therefore, the aircraft also becomes larger and heavier.

[0005] Therefore, attempts have been made to obtain high torque while avoiding the motor becoming large. For example, Patent Document 1 proposes a structure in which the arc angle of the teeth facing the permanent magnet is specified. Patent Document 1 exemplifies a motor having 16 permanent magnets and 18 teeth. In this case, the number of teeth facing the north pole or south pole of one permanent magnet is approximately one.

[0006] Patent Documents 2 and 3 also propose structures for obtaining high torque in a motor. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2005-80381 A [Patent Document 2] JP 2007-151332 A [Patent Document 3] JP 2007-209197 A Summary of the Invention [Problem to be solved by the invention]

[0008] In order to further reduce the weight of flying objects and the like, there is a demand for further reducing the weight of motors. In order to meet this demand, for example, it is conceivable to form so-called weight reductions in the rotor core. Specifically, a plurality of through holes are formed between a first insertion hole into which a rotating shaft is inserted and a second insertion hole into which a magnet is inserted. In this case, the rotor core has an inner annular portion, an outer annular portion, and a connecting portion. The inner annular portion is a portion located on the inner circumference of the through hole, and is a portion where the first insertion hole is formed. The outer annular portion is a portion located on the outer circumference of the through hole, and is a portion where the second insertion hole is formed. The connecting portion is a portion located between adjacent through holes, and is a portion that connects the inner annular portion and the outer annular portion.

[0009] In such a configuration, it is conceivable to increase the number of permanent magnets in order to obtain high torque when the rotation speed is low. Here, the permanent magnets are held in the outer annular portion as described above. Therefore, if the rigidity of the connecting portion is low, there is a concern that the connecting portion may bend due to the weight of the permanent magnets. For these reasons, it is not easy to reduce the weight of a rotating electric machine that can obtain high torque.

[0010] The present invention aims to solve the above-mentioned problems. [Means for solving the problem]

[0011] According to one embodiment of the present invention, there is provided a stator having a yoke portion having an annular shape and a plurality of teeth portions protruding from an inner peripheral edge of the yoke portion toward a radially inward direction of the yoke portion, with slots formed between adjacent teeth portions of the plurality of teeth portions; a rotor disposed inside the stator and facing the plurality of teeth portions; A rotating electric machine comprising: The rotor has a rotor core that holds a permanent magnet with 16 to 32 poles, and a rotating shaft that rotates integrally with the rotor core, The rotor core is a laminate of a plurality of electromagnetic steel plates, Each of the plurality of electromagnetic steel plates is formed with a first insertion hole in which the rotating shaft is disposed, a plurality of through holes formed radially outward of the first insertion hole, and a plurality of second insertion holes formed radially outward of the plurality of through holes and into which the permanent magnets are inserted, and each of the plurality of electromagnetic steel sheets has an inner annular portion located between the plurality of through holes and the first insertion hole, an outer annular portion located radially outward of the plurality of through holes and in which the plurality of second insertion holes are formed, and a plurality of connecting portions connecting the inner annular portion and the outer annular portion, The intersection angle between adjacent connection portions in the circumferential direction of the rotor is 12° to 36°, In the rotor core, the plurality of electromagnetic steel sheets are laminated in a first manner or a second manner, The first aspect is an aspect in which the plurality of electromagnetic steel sheets are stacked such that the plurality of connecting portions of one adjacent electromagnetic steel sheet in the plurality of electromagnetic steel sheets and the plurality of connecting portions of the other adjacent electromagnetic steel sheets in the plurality of electromagnetic steel sheets are not overlapped when the rotor is viewed in the axial direction of the rotor, The second aspect provides a rotating electric machine in which a plurality of plate groups, each having a plurality of the electromagnetic steel plates, are stacked in the axial direction, and the plurality of connecting portions of one adjacent plate group in the plurality of plate groups and the plurality of connecting portions of the other adjacent plate group in the plurality of plate groups are stacked in positions that do not overlap when the rotor is viewed in the axial direction. Effect of the Invention

[0012] In the present invention, the connecting parts are formed in the shape of a windmill blade. Also, the intersection angle between one of the connecting parts and another connecting part adjacent to the connecting part is set within the range of 12° to 36°. By setting the intersection angle in this way, even when the number of poles is large, such as 16 to 32 poles (the number of permanent magnets is large), a connecting part that exhibits sufficient rigidity can be obtained. Therefore, the connecting part is less likely to bend. Also, the durability of the connecting part is improved.

[0013] In addition, since the number of poles is large (the number of permanent magnets is large), at 16 to 32, sufficient magnetic flux density can be obtained, and therefore high torque can be obtained.

[0014] Furthermore, since the rotor core has a plurality of through holes, the rotor core is lightweight, and therefore the weight of the rotating electrical machine can be reduced. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic horizontal cross-sectional view of a main portion of a rotating electrical machine according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an enlarged view of a main portion of FIG. [Diagram 3] FIG. 3 is a schematic overall plan view of the rotor core. [Figure 4] FIG. 4 is a schematic overall plan view of one electromagnetic steel plate forming the rotor core. [Diagram 5] FIG. 5 is an exploded perspective view of a main portion of the rotor core. [Figure 6] FIG. 6 is an exploded perspective view of a main portion of another rotor core. [Figure 7] FIG. 7 is an enlarged view of a main portion of FIG. [Figure 8] FIG. 8 is a schematic horizontal cross-sectional view of a main part of a rotating electric machine according to another embodiment of the present invention. [Figure 9] FIG. 9 is a schematic horizontal cross-sectional view of a main part of a rotating electric machine according to still another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] 1 is a schematic horizontal cross-sectional view of a main portion of a rotating electric machine 10 according to this embodiment. The rotating electric machine 10 includes a stator 12 having a substantially annular shape and a rotor 14 disposed inside the stator 12. The rotating electric machine 10 is, for example, a three-phase motor having a U-phase, a V-phase, and a W-phase.

[0017] First, a description will be given of the stator 12. The stator 12 has a stator core 20. The stator core 20 is a laminate in which magnetic bodies such as electromagnetic steel sheets are laminated.

[0018] The stator core 20 has a yoke portion 24 and a plurality of teeth portions 26. In this embodiment, the outer diameter of the rotating electric machine 10 (twice the distance X from the center O of the rotating shaft 50 to the outer periphery of the yoke portion 24) is within a range of 230 mm to 450 mm. This outer diameter is smaller than the outer diameter of a general motor that rotates a propeller of a flying object. In other words, the rotating electric machine 10 is small in size.

[0019] The yoke portion 24 has an annular shape. The teeth portion 26 protrude inward from the inner peripheral edge of the yoke portion 24 along the radial direction of the yoke portion 24.

[0020] Slots 28 are formed between adjacent teeth 26. When the rotating electric machine 10 is a three-phase motor, the number of slots 28 is typically a multiple of three. In the example shown in FIG. 1, the number of teeth 26 and slots 28 is 96. The number of poles (described below) is 16. Therefore, the rotating electric machine 10 is configured as a so-called 16-pole, 96-slot configuration. An electromagnetic coil 30 is provided in the slot 28. The electromagnetic coil 30 is, for example, a wire made of copper. The electromagnetic coil 30 is obtained by winding the wire around the teeth 26.

[0021] Fig. 2 is an enlarged view of the main parts of Fig. 1. Each tooth portion 26 has a rod portion 32, a flange portion 34, and an expansion portion 36. The rod portion 32 extends radially along the radial direction of the stator core 20. The flange portion 34 is provided at the inner peripheral tip of the tooth portion 26. The expansion portion 36 is interposed between the rod portion 32 and the flange portion 34.

[0022] The rod portion 32 has a first parallel side 40a and a second parallel side 40b. A distance W1 between the first parallel side 40a and the second parallel side 40b is referred to as a width dimension of the rod portion 32. The width direction is approximately perpendicular to the radial direction of the stator core 20.

[0023] The expanding portion 36 gradually becomes wider from the rod portion 32 toward the flange portion 34. In other words, the expanding portion 36 is formed in a tapered shape toward the rod portion 32. The expanding portion 36 has a first inclined side 42a and a second inclined side 42b. The first inclined side 42a intersects with the first parallel side 40a of the rod portion 32 at an intersection angle θ1. Similarly, the second inclined side 42b intersects with the second parallel side 40b at an intersection angle θ2. In this embodiment, the intersection angles θ1 and θ2 are in the range of 108° to 130°. More preferably, the intersection angles θ1 and θ2 are in the range of 120° to 125°. By setting the intersection angles θ1 and θ2 in such a range, the total copper loss and iron loss in the stator 12 is reduced. It is preferable that the intersection angles θ1 and θ2 are the same. However, the crossing angle θ1 and the crossing angle θ2 may be different.

[0024] The intersection point between the first parallel side 40a and the first inclined side 42a is defined as P1. The intersection point between the second parallel side 40b and the second inclined side 42b is defined as P2. The straight line drawn from the intersection point P1 to the intersection point P2 is defined as the first imaginary straight line LN1. The first imaginary straight line LN1 represents the inner peripheral end of the rod portion 32. At the same time, the first imaginary straight line LN1 represents the outer peripheral end of the expansion portion 36.

[0025] The first inclined side 42a is connected to the first radial side 44a of the flange portion 34. The second inclined side 42b is connected to the second radial side 44b of the flange portion 34. The first radial side 44a and the second radial side 44b are substantially linear and extend parallel to each other. Hereinafter, the distance between the first radial side 44a and the second radial side 44b is defined as W2. The distance W2 is the width of the flange portion 34. The width W2 of the flange portion 34 is greater than the width W1 of the rod portion 32.

[0026] The distance between adjacent flange portions 34 is G. The diameter of the wire forming the electromagnetic coil 30 is DM. The width W2 is, for example, in a range in which the distance G is greater than the diameter DM. In this case, magnetic flux saturation at the flange portions 34 is reduced. As a result, the rod portion 32 can receive a large amount of magnetic flux. This can improve the rotational torque of the rotating shaft 50. In addition, it is possible to select a magnetic material with a small saturation magnetic flux density as the material (electromagnetic steel sheet, etc.) of the stator core 20. This can also reduce costs.

[0027] The intersection point between the first inclined side 42a and the first radial side 44a is defined as P3. The intersection point P3 is the outer peripheral end of the first radial side 44a (the inner peripheral end of the first inclined side 42a). The intersection point between the second inclined side 42b and the second radial side 44b is defined as P4. The intersection point P4 is the outer peripheral end of the second radial side 44b (the inner peripheral end of the second inclined side 42b). The straight line drawn from the intersection point P3 to the intersection point P4 is defined as a second imaginary straight line LN2. The second imaginary straight line LN2 represents the inner peripheral end of the expansion portion 36 and also represents the outer peripheral end of the flange portion 34.

[0028] A straight line drawn from the inner peripheral end of the first radial side 44a to the inner peripheral end of the second radial side 44b is defined as a third imaginary straight line LN3. The third imaginary straight line LN3 is the inner peripheral end of the flange portion 34. The distance between the third imaginary straight line LN3 and the second imaginary straight line LN2 is defined as T1. The distance T1 represents the distance from the inner peripheral end of the flange portion 34 to the outer peripheral end of the flange portion 34. Hereinafter, the distance T1 is defined as the thickness of the flange portion 34.

[0029] A preferable range of the thickness T1 of the flange portion 34 is 0.2 mm to 2.0 mm. A more preferable range of the thickness T1 is 0.3 mm to 1.1 mm. When the thickness T1 is in this range, the total of the copper loss and the iron loss in the stator 12 becomes small.

[0030] The outer peripheral end of the rod portion 32 is a point connected to the inner peripheral edge of the yoke portion 24. The distance from the outer peripheral end of the rod portion 32 to the inner peripheral end of the flange portion 34 is defined as the overall length LO of the teeth portion 26 (see FIG. 2). In a typical example, the overall length LO is within a range of 40 mm to 45 mm. Also, in a typical example, when the overall length LO is 100%, the overall length of the rod portion 32 is 96% or more. In this case, the distance from the inner peripheral end of the flange portion 34 to the inner peripheral end of the rod portion 32 is 4% or less of the overall length LO of the teeth portion 26.

[0031] In this embodiment, the electromagnetic coil 30 is made of a metal conductor such as copper. As described above, the electromagnetic coil 30 is formed by winding a wire around the teeth portion 26. In this embodiment, distributed winding is performed. Fig. 1 illustrates the case of so-called two-turn winding.

[0032] As shown in FIG. 2, in a cross section perpendicular to the axial direction of the rotating shaft 50, the inner peripheral end of the electromagnetic coil 30 is located within the slot 28. The inner peripheral end of the electromagnetic coil 30 is located between the inner peripheral end of the flange portion 34 and the outer peripheral end of the rod portion 32. Therefore, the inner peripheral end of the electromagnetic coil 30 is offset toward the yoke portion 24 (the outer periphery of the stator core 20). In FIG. 2, the inner peripheral end of the electromagnetic coil 30 is located between the outer peripheral end of the expansion portion 36 (the inner peripheral end of the rod portion 32) and the outer peripheral end of the rod portion 32. The distance from the inner peripheral end of the flange portion 34 to the inner peripheral end of the electromagnetic coil 30 is defined as the offset amount OF. The offset amount OF is preferably in the range of 5% to 11% of the overall length LO of the teeth portion 26. For example, when the overall length LO is 40 mm, the suitable offset amount OF is 2 mm to 4.4 mm. A more preferable range for the offset amount OF is 5.6% to 10.3% of the overall length LO of the teeth portion 26.

[0033] If the offset OF is less than 5% of the total length LO of the teeth portion 26, the amount of turns of the electromagnetic coil 30 increases. This increases the volume of the electromagnetic coil 30. As a result, the amount of magnetic flux received from the permanent magnets 54 of the rotor 14 increases. This raises the concern that the amount of heat generated by the electromagnetic coil 30 will increase. In addition, the copper loss will increase. If the offset OF exceeds 11%, the copper loss will decrease. However, the exposed area of ​​the rod portion 32 will increase, resulting in increased iron loss. As a result, the amount of heat generated will increase. In addition, the amount of turns of the electromagnetic coil 30 will decrease, resulting in a smaller volume of the electromagnetic coil 30. This will result in a decrease in the output of the rotating electric machine 10 as a motor.

[0034] When the overall length LO of the teeth portion 26 is 40 mm to 45 mm, the specific distance from the first imaginary straight line LN1 to the inner peripheral end of the electromagnetic coil 30 is typically 1 to 3 mm. As described above, the first imaginary straight line LN1 is the inner peripheral end of the rod portion 32 and the outer peripheral end of the expansion portion 36.

[0035] The rotor 14 will now be described. As shown in FIG.

[0036] The rotor 14 has a rotating shaft 50, a rotor core 52, and a plurality of (32 in the example of FIG. 1) permanent magnets 54. The rotor core 52 rotates integrally with the rotating shaft 50. The permanent magnets 54 are held by the rotor core 52. Therefore, when the rotating shaft 50 rotates, the permanent magnets 54 move along the outer circumferential edge of the rotor core 52.

[0037] 3, rotor core 52 has a plurality of electromagnetic steel sheets 60. Rotor core 52 is formed by stacking a plurality of electromagnetic steel sheets 60. In other words, rotor core 52 is a laminate of a plurality of electromagnetic steel sheets 60.

[0038] As shown in Fig. 4, one electromagnetic steel sheet 60 is a thin-walled, annular body. The electromagnetic steel sheet 60 has an inner annular portion 62 located on the inner circumference and an outer annular portion 64 located on the outer circumference. The inner annular portion 62 and the outer annular portion 64 are substantially annular and concentric. The inner annular portion 62 and the outer annular portion 64 are connected via a plurality of connecting portions 66 (ten in the example of Fig. 4). In this manner, the connecting portions 66 connect the outer peripheral edge of the inner annular portion 62 and the inner peripheral edge of the outer annular portion 64.

[0039] A circular first insertion hole 70 is formed in the inner annular portion 62. The rotating shaft 50 shown in FIG.

[0040] If the distance from the center O to the inner peripheral edge of the inner annular portion 62 is Rin (see FIG. 3), then twice Rin is the inner diameter of the rotor core 52. If the distance from the center O to the outer peripheral edge of the outer annular portion 64 is Rout, then twice Rout is the outer diameter of the rotor core 52. Hereinafter, the inner diameter of the rotor core 52 will be referred to as the "rotor inner diameter" and the outer diameter of the rotor core 52 will be referred to as the "rotor outer diameter". The rotor outer diameter is larger than the rotor inner diameter.

[0041] The rotor outer diameter is preferably 1.5 to 3.5 times the rotor inner diameter. That is, the ratio of the rotor inner diameter to the rotor outer diameter is preferably within a range of 1:1.5 to 1:3.5. In this case, Rin:Rout=1:1.5 to 3.5 holds true.

[0042] A through hole 72 is formed between adjacent connecting portions 66. A plurality of second insertion holes 74 (32 in the example of FIG. 4) are formed in the outer annular portion 64. Each second insertion hole 74 has a rectangular shape. Two second insertion holes 74 are adjacent to each other and form a pair. Hereinafter, a pair of second insertion holes 74 (two second insertion holes 74 adjacent to each other) will be referred to as a "hole group 76." The distance between adjacent hole groups 76 is greater than the distance between second insertion holes 74 within one hole group 76. Between the second insertion holes 74 in one hole group 76 and adjacent to this hole group 76 hole group 76 Second insertion hole 74 Peer Between In this case, the separation angle (phase difference) α is 22.5°.

[0043] The permanent magnets 54 are inserted into the second insertion holes 74. Since there are 32 second insertion holes 74, there are also 32 permanent magnets 54. Two permanent magnets 54 are inserted into one set of hole groups 76 with the same magnetic pole facing the outer periphery. In FIG. 3, the north pole of the permanent magnets 54 is shown with a mesh. In contrast, the south pole is not shown with a mesh. The same applies to the subsequent drawings.

[0044] As can be seen from Fig. 3, in any one pair of hole groups 76, the N poles of the two permanent magnets 54 face the outer periphery. In this case, in the hole group 76 adjacent to the hole group 76, the S poles of the two permanent magnets 54 face the outer periphery. In the following description, when simply written as "N pole" or "S pole", it indicates a magnetic pole facing the outer periphery. In the stator 12, two N poles are interposed between two other two N poles.

[0045] Hereinafter, the same magnetic poles facing the outer periphery of the two permanent magnets 54 housed in one set of hole groups 76 are counted as one pole. That is, two adjacent N poles in one set of hole groups 76 are one pole. Similarly, two adjacent S poles in another set of hole groups 76 are also one pole. In this embodiment, 16 sets of hole groups 76 are formed. Therefore, the number of magnetic poles is 16. In this manner, the rotating electric machine 10 is a three-phase motor with 16 poles. In this specification, the number of magnetic poles determined in this manner is defined as the "number of poles."

[0046] One connecting portion 66 extends from the outer peripheral edge of the inner annular portion 62 to the inner peripheral edge of the outer annular portion 64. The extending direction of the connecting portion 66 is inclined with respect to the diameter of the electromagnetic steel sheet 60. In the illustrated example (FIG. 4), the number of connecting portions 66 is ten. Therefore, the intersection angle β between adjacent connecting portions 66 is 36°.

[0047] However, the number of the connecting portions 66 is not limited to 10. Accordingly, the intersection angle β is also not limited to 36°. A preferable number of the connecting portions 66 is 10 to 30. A preferable range of the intersection angle β is 12° to 36°. When the intersection angle β is within this range, the connecting portions 66 exhibit sufficient rigidity. Therefore, bending of the connecting portions 66 under the total weight of the outer annular portion 64 and the permanent magnets 54 is prevented.

[0048] In particular, it is preferable to increase the number of connecting portions 66 as the number of permanent magnets 54 (or the number of poles) increases. For example, when the number of poles is 32, it is preferable to have 30 connecting portions 66. In this case, the intersection angle β between adjacent connecting portions 66 is 12°. When the number of poles is 24, it is preferable to have 18 connecting portions 66. In this case, the intersection angle β between adjacent connecting portions 66 is 20°.

[0049] FIG. 5 is an exploded perspective view of a main portion of the rotor core 52. Four electromagnetic steel sheets 60 are shown in FIG. 5. For ease of understanding, the lowest electromagnetic steel sheet 60 in FIG. 5 is referred to as a first electromagnetic steel sheet 601. The hole group 76 of the first electromagnetic steel sheet 601 is referred to as a first hole group 761, and the connecting portion 66 of the first electromagnetic steel sheet 601 is referred to as a first connecting portion 661. The electromagnetic steel sheet 60 stacked directly above the first electromagnetic steel sheet 601 is referred to as a second electromagnetic steel sheet 602. The hole group 76 of the second electromagnetic steel sheet 602 is referred to as a second hole group 762, and the connecting portion 66 of the second electromagnetic steel sheet 602 is referred to as a second connecting portion 662. The electromagnetic steel sheet 60 stacked directly above the second electromagnetic steel sheet 602 is referred to as a third electromagnetic steel sheet 603. The hole group 76 of the third electromagnetic steel sheet 603 is referred to as a third hole group 763, and the connecting portion 66 of the third electromagnetic steel sheet 603 is referred to as a third connecting portion 663. The electromagnetic steel sheet 60 stacked directly above the third electromagnetic steel sheet 603 is referred to as a fourth electromagnetic steel sheet 604. The hole group 76 of the fourth electromagnetic steel sheet 604 is referred to as a fourth hole group 764, and the connecting portion 66 of the fourth electromagnetic steel sheet 604 is referred to as a fourth connecting portion 664.

[0050] The second electromagnetic steel sheet 602 is laminated on the first electromagnetic steel sheet 601 in a state rotated by 45° with respect to the first electromagnetic steel sheet 601. In this case, a phase difference of 9° occurs between the first connecting portion 661 and the second connecting portion 662. In addition, the first hole group 761 and the second hole group 762 overlap with each other. In other words, the first hole group 761 and the second hole group 762 are connected to each other.

[0051] The third electromagnetic steel sheet 603 is laminated on the second electromagnetic steel sheet 602 while being rotated 45° relative to the second electromagnetic steel sheet 602 and rotated 90° relative to the first electromagnetic steel sheet 601. In this case, a phase difference of 9° occurs between the second connecting portion 662 and the third connecting portion 663, and a phase difference of 18° occurs between the first connecting portion 661 and the third connecting portion 663. In addition, the third hole group 763 is connected to the first hole group 761 and the second hole group 762.

[0052] The fourth electromagnetic steel sheet 604 is laminated on the third electromagnetic steel sheet 603 in a state where it is rotated 45° relative to the third electromagnetic steel sheet 603, rotated 90° relative to the second electromagnetic steel sheet 602, and rotated 135° relative to the first electromagnetic steel sheet 601. In this case, a phase difference of 9° occurs between the third connecting portion 663 and the fourth connecting portion 664, a phase difference of 18° occurs between the second connecting portion 662 and the fourth connecting portion 664, and a phase difference of 27° occurs between the first connecting portion 661 and the fourth connecting portion 664. In addition, the fourth hole group 764 is connected to the first hole group 761, the second hole group 762, and the third hole group 763.

[0053] A combination of the first to fourth electromagnetic steel sheets 601-604 is referred to as one set of sheet groups 80. One set of sheet groups 80 is stacked with another set of sheet groups 80. Thus, the first electromagnetic steel sheet 601 in the other set of sheet groups 80 is stacked directly above the fourth electromagnetic steel sheet 604 in one set of sheet groups 80. When the rotor 14 is viewed in the axial direction of the rotor 14, the positions of the first hole group 761 and the first coupling portion 661 in the first electromagnetic steel sheet 601 in the lower sheet group 80 correspond to the positions of the first hole group 761 and the first coupling portion 661 in the first electromagnetic steel sheet 601 in the upper sheet group 80 (they overlap each other).

[0054] When the rotor 14 is viewed in the axial direction of the rotor 14, the first hole group 761, the second hole group 762, the third hole group 763, and the fourth hole group 764 are all connected to each other. The permanent magnet 54 is passed through all of the hole groups 76 along the lamination direction of the electromagnetic steel sheets 60. In addition, the inner annular portions 62 of the first to fourth electromagnetic steel sheets 601 to 604 all overlap each other.

[0055] In contrast, when the rotor 14 is viewed in the axial direction of the rotor 14, the second connecting portion 662, the third connecting portion 663, and the fourth connecting portion 664 are interposed between adjacent first connecting portions 661. A clearance is formed between the first connecting portion 661 and the second connecting portion 662. A clearance is also formed between the second connecting portion 662 and the third connecting portion 663. A clearance is also formed between the third connecting portion 663 and the fourth connecting portion 664. A clearance is also formed between the fourth connecting portion 664 and the first connecting portion 661. Therefore, the through hole 72 between adjacent first connecting portions 661 is not blocked by the second connecting portion 662, the third connecting portion 663, and the fourth connecting portion 664.

[0056] Therefore, in rotor core 52, parts of through holes 72 overlap one another along the stacking direction of electromagnetic steel sheets 60. Because through holes 72 are connected in this manner, flow passages 82 (through holes 72) are formed in rotor core 52 along the stacking direction of electromagnetic steel sheets 60, as shown in FIG.

[0057] As shown in FIG. 6, a plurality of electromagnetic steel sheets 60 may be stacked in a phase where all the connecting portions 66 overlap each other to provide one plate group 81. In this case, when another plate group 81 is stacked directly on top of the plate group 81, the connecting portions 66 of the lower plate group 81 and the connecting portions 66 of the upper plate group 81 are in a phase where they do not overlap. For example, a phase difference of 9° is provided between the connecting portions 66 of the lower plate group 81 and the connecting portions 66 of the upper plate group 81. The plate group 81 to be stacked next is also in a phase where the connecting portions 66 of the plate group 81 do not overlap the connecting portions 66 of the two plate groups 81 already stacked (phase difference of 9°). The plate group 81 to be stacked next is also in a phase where the connecting portions 66 of the plate group 81 do not overlap the connecting portions 66 of the three plate groups 81 already stacked (phase difference of 9°). The above stacking may be repeated. In either case, when the rotor 14 is viewed in the axial direction of the rotor 14, it has the shape shown in FIG. 3. That is, the rotor core 52 is obtained.

[0058] The two permanent magnets 54 provided in one set of hole groups 76 are either N poles or S poles as described above. That is, the number of poles of the permanent magnets 54 in one set of hole groups 76 is one pole. The two permanent magnets 54 face the rod portion 32 via the flange portion 34. In this embodiment, the number of poles is 16, and the number of teeth portions 26 is 96. Therefore, the average number of teeth portions 26 for one pole (in this embodiment, two permanent magnets 54 provided in one set of hole groups 76) is six.

[0059] Since the number of teeth 26 is 96, the number of slots 28 is also 96. Therefore, the average number of slots 28 per magnetic pole is also 6 (see FIG. 7). In this manner, the average number of teeth 26 or slots 28 per magnetic pole can be found by calculation.

[0060] In Figure 7, 1 very of magnetic This shows the moment when the poles (two permanent magnets 54 provided in one set of hole groups 76) face six slots 28. In this case, approximately half of the teeth 26 face the lower S pole, and approximately half of the other teeth 26 face the upper S pole. In addition, all five teeth 26 face two S poles. Therefore, even in this case, the average number of teeth 26 facing two S poles is six.

[0061] When the rotor 14 is rotated slightly from the position shown in FIG. 7, all six teeth 26 face between two permanent magnets 54 provided in one set of hole groups 76. Approximately half of the slots 28 face the lower S pole, and approximately half of another slot 28 faces the upper S pole. In addition, all five slots 28 face two S poles. Therefore, even in this case, the average number of slots 28 facing two S poles is six.

[0062] The rotor 14 has a rotating shaft 50. The rotating shaft 50 is rotatably supported by a support member (not shown). A bearing (not shown) is provided on the rotating shaft 50. The bearing is disposed between the rotating shaft 50 and the support member.

[0063] A rotating body (not shown) is attached to the tip of the rotating shaft 50. The rotating shaft 50 and the rotating body may be connected via a gear or the like. In either case, the rotating body rotates as the rotating shaft 50 rotates when electricity is applied to the electromagnetic coil 30. The rotating body is, for example, a propeller.

[0064] The rotating electrical machine 10 according to this embodiment is basically configured as described above. Next, the effects of the rotating electrical machine 10 will be described.

[0065] As described above, rotor core 52 is formed by stacking a plurality of electromagnetic steel sheets 60. Each electromagnetic steel sheet 60 has a through hole 72 formed therein. Therefore, each electromagnetic steel sheet 60 is lightweight. As a result, rotor core 52 is lightweight. As a result, rotating electric machine 10 is also lightweight.

[0066] As described above, in this embodiment, the outer diameter of the rotating electric machine 10 is a maximum of 450 mm. That is, the rotating electric machine 10 is relatively small. In this way, according to this embodiment, the rotating electric machine 10 can be made smaller and lighter.

[0067] The rotating electric machine 10 is used, for example, as a rotation drive source for a propeller of a flying object. In this case, the rotating electric machine 10 is used as a three-phase motor.

[0068] In order to operate the rotating electric machine 10 as a three-phase motor, electricity is applied to the electromagnetic coil 30. When electricity is applied, the electromagnetic coil 30 generates an alternating magnetic field. The alternating magnetic field either repels or attracts the magnetic field of the permanent magnet 54. As a result, the rotating shaft 50 and the rotor core 52 rotate integrally. Therefore, the permanent magnet 54 moves in a circular motion along the outer edge of the rotor core 52.

[0069] In order to obtain high torque when the rotation speed of the rotating shaft 50 is low, it is necessary to use a bearing with a large diameter. The rotor inner diameter is set to a size capable of supporting a bearing with a large diameter. Here, when the ratio of the rotor inner diameter to the rotor outer diameter is within a range of 1:1.5 to 1:3.5, the diameter of the electromagnetic steel sheet 60 (diameter of the rotor 14) is prevented from becoming large. Therefore, in this case, the rotor 14 is small in size but can support a bearing with a large diameter.

[0070] Each electromagnetic steel plate 60 of the rotor core 52 has a connecting portion 66. The intersection angle β between adjacent connecting portions 66 is within a range of 12° to 36°. This allows an appropriate number of connecting portions 66 to be determined. Therefore, the outer annular portion 64 is sufficiently supported by the inner annular portion 62 via the connecting portions 66. This allows the rotor core 52 to hold a large number of permanent magnets 54. In other words, the number of poles can be increased. Therefore, the rotational torque of the rotating shaft 50 can be increased.

[0071] In the example of FIG. 1, the number of magnetic poles is 16, and the number of slots 28 is 96. Therefore, the number of slots 28 facing one magnetic pole (two permanent magnets 54 inserted into one set of hole groups 76) is six. In this manner, in this embodiment, the number of slots 28 facing one magnetic pole is appropriately determined. As a result, the rotation torque of the rotating shaft 50 is large, even though the diameter of the rotating electric machine 10 is relatively small. In other words, the rotating electric machine 10 can impart a large rotational driving force to a rotating body such as a propeller, even though it is a small and lightweight three-phase motor.

[0072] Moreover, in this case, leakage magnetic flux is reduced, which results in a reduction in the interlinking magnetic flux of the electromagnetic coil 30. Therefore, eddy currents in the electromagnetic coil 30 are reduced, and heat generation by the electromagnetic coil 30 is suppressed.

[0073] Furthermore, in the teeth portion 26, the intersection angles θ1, θ2 between the rod portion 32 and the expansion portion 36 are within a range of 108° to 130°. The thickness T1 of the flange portion 34 is within a range of 0.2 mm to 2.0 mm. The offset amount OF of the electromagnetic coil 30 with respect to the teeth portion 26 is within a range of 5 to 11%. By setting the intersection angle θ, the thickness T1, and the offset amount OF within these ranges, the total of the iron loss and copper loss in the stator 12 can be reduced. Therefore, heat generation in the stator 12 is suppressed.

[0074] Furthermore, by appropriately setting the offset amount OF, leakage magnetic flux is reduced, which prevents, for example, localized temperature rise in the teeth portion 26 or the electromagnetic coil 30. This prevents deterioration of the material of the stator core 20 (electromagnetic steel sheet 60, etc.) or the material of the electromagnetic coil 30 (copper, etc.) caused by this temperature rise.

[0075] As described above, according to this embodiment, it is possible to improve the rotational torque of the rotating shaft 50 while reducing the size and weight of the rotating electric machine 10. Therefore, when the rotating electric machine 10 is used as a motor, it is possible to continuously output high torque. Moreover, as described above, heat generation in the rotating electric machine 10 is suppressed.

[0076] A cooling medium (e.g., cooling air) is supplied to the rotating electric machine 10. A part of the cooling medium passes between the stator core 20 and the rotor core 52. Another part of the cooling medium passes through a flow passage 82 (through hole 72) formed in the rotor core 52. In this manner, the rotating electric machine 10 is cooled.

[0077] In the rotor core 52, a phase difference is provided between one electromagnetic steel sheet 60 and the electromagnetic steel sheet 60 stacked directly above it. Therefore, a phase difference is also generated between the through holes 72 of the two stacked electromagnetic steel sheets 60. This prevents the cooling medium from concentrating or stagnating in one flow passage 82 in the rotor core 52. In other words, the cooling medium is distributed approximately evenly to the multiple circulation holes, and then the distributed cooling medium easily flows through each of the circulation holes. Therefore, the entire rotating electric machine 10 is efficiently and approximately evenly cooled.

[0078] During rotation of rotor core 52, stress acts on rotor core 52. Here, in the two laminated electromagnetic steel sheets 60, a phase difference also occurs between the connecting portions 66. For this reason, stress is dispersed between the connecting portions 66 with the phase difference. This prevents stress from concentrating on any one of the connecting portions 66. For these reasons, the durability of the connecting portions 66 is improved.

[0079] As described above, this embodiment relates to a stator (12) having an annular yoke portion (24) and a plurality of teeth portions (26) protruding radially inward from an inner peripheral edge of the yoke portion, with slots (28) formed between adjacent teeth portions of the plurality of teeth portions; a rotor (14) disposed inside the stator and facing the plurality of teeth portions; A rotating electric machine (10) comprising: The rotor includes a rotor core (52) that holds a permanent magnet (54) having 16 to 32 poles, and a rotating shaft (50) that rotates integrally with the rotor core, The rotor core is a laminate (60) of a plurality of electromagnetic steel plates, Each of the plurality of electromagnetic steel plates has a first insertion hole (70) in which the rotating shaft is disposed, a plurality of through holes (72) formed radially outward of the first insertion hole, and a plurality of second insertion holes (74) formed radially outward of the plurality of through holes and into which the permanent magnets are inserted. (74) and are formed, And the plurality of pcsEach of the electromagnetic steel sheets has an inner annular portion (62) located between the plurality of through holes and the first insertion hole, an outer annular portion (64) located radially outward of the plurality of through holes and in which the plurality of second insertion holes are formed, and a plurality of connecting portions (66) connecting the inner annular portion and the outer annular portion, The intersection angle (β) between adjacent connection portions in the circumferential direction of the rotor is 12° to 36°, The present invention discloses a rotating electric machine in which the rotor core is formed by stacking a plurality of electromagnetic steel sheets in the first aspect or the second aspect.

[0080] In a first aspect, the plurality of electromagnetic steel sheets are stacked such that the plurality of connecting portions (661) of one adjacent electromagnetic steel sheet (601) in the plurality of electromagnetic steel sheets and the plurality of connecting portions (662) of the other adjacent electromagnetic steel sheet (602) in the plurality of electromagnetic steel sheets are not overlapped when the rotor is viewed in the axial direction of the rotor.

[0081] In the second aspect, a plurality of plate groups (81), each having a plurality of the electromagnetic steel plates, are stacked in the axial direction, and the plurality of connecting portions (661) of one adjacent plate group in the plurality of plate groups and the plurality of connecting portions (662) of the other adjacent plate group in the plurality of plate groups are stacked in positions that do not overlap when the rotor is viewed in the axial direction.

[0082] In this rotating electric machine, the connecting parts are formed in the shape of a windmill blade. Furthermore, in one electromagnetic steel plate, the intersection angle between one of the connecting parts and another connecting part adjacent to the one connecting part is set within the range of 12° to 36°. By setting the intersection angle in this manner, even when the number of poles is large, such as 16 to 32 poles (the number of permanent magnets is large), a connecting part that exhibits sufficient rigidity is obtained. Therefore, the connecting part is less likely to bend. Furthermore, the durability of the connecting part is improved.

[0083] In addition, since the number of poles is large (the number of permanent magnets is large), at 16 to 32, sufficient magnetic flux density can be obtained, and therefore high torque can be obtained.

[0084] In addition, since the rotor core has a plurality of through holes, the rotor core is lightweight, and therefore the weight of the rotating electrical machine can be reduced. For the above reasons, it is possible to reduce the weight of the rotating electrical machine and obtain a sufficiently high torque.

[0085] To obtain a rotor core made of a single member having a large thickness, it is necessary to form the first insertion hole, the through hole, and the second insertion hole, for example, by performing a drilling process on a cylindrical workpiece. However, it is not easy to perform a drilling process on a workpiece having a large thickness. In contrast, when obtaining a rotor core by stacking electromagnetic steel sheets having the above-mentioned shape, the first insertion hole, the through hole, and the second insertion hole are formed simply by stacking the electromagnetic steel sheets.

[0086] Each electromagnetic steel sheet is obtained, for example, by punching a thin, disk-shaped workpiece to form the first insertion hole, the through hole, and the second insertion hole. The punching process for a thin, disk-shaped workpiece can be performed more easily than the drilling process for a thicker workpiece. Therefore, the rotor core can be easily manufactured.

[0087] Since the connecting parts of the two electromagnetic steel sheets (or two groups of sheets) stacked one above the other do not overlap, stress concentration at a connecting part of any phase is avoided. In other words, stress is appropriately distributed to each of the connecting parts of different phases. This improves the durability of the connecting parts.

[0088] This embodiment discloses a rotating electric machine in which the average number of the slots for one magnetic pole is six when the stator and the rotor are viewed in the axial direction of the stator.

[0089] In this case, the average number of slots and teeth facing one magnetic pole is appropriately determined. This allows the rotational torque of the rotating shaft to be large even if the diameter of the rotating electric machine is relatively small. Therefore, when the rotating electric machine is used as a three-phase motor, it is possible to apply a large rotational driving force to the rotating body provided on the rotating shaft, despite its small size and light weight. In other words, the rotating electric machine is capable of continuously outputting high torque.

[0090] Moreover, in this case, leakage flux is reduced, which results in a reduction in flux linkage of the electromagnetic coil, thereby reducing eddy currents in the electromagnetic coil and suppressing heat generation in the electromagnetic coil.

[0091] In addition, the number of poles and the number of slots are determined as above. In this case, it is possible to obtain a large rotational torque from the rotating shaft while preventing the diameter of the rotating electric machine from becoming excessively large. Therefore, it is possible to obtain a small-sized motor with high output.

[0092] This embodiment discloses a rotating electric machine in which the outer diameter of the stator is within a range of 230 to 450 mm. Note that the "outer diameter of the stator" is synonymous with "twice the distance from the center of the rotating shaft to the outer edge of the stator core." Therefore, the "outer diameter of the stator" can be rephrased as the "outer diameter of the rotating electric machine."

[0093] A rotating electric machine with such an outer diameter is relatively small, that is, the rotating electric machine is capable of continuously outputting high torque despite its small size.

[0094] The present invention is not limited to the above-described embodiment, and various configurations can be adopted without departing from the gist of the present invention.

[0095] In the above-described embodiment, a rotating electric machine 10 with 16 poles and 96 slots is exemplified. However, the number of poles or the number of slots 28 is not particularly limited to this. For example, as shown in FIG. 8, a rotating electric machine 90 with 24 poles and 144 slots may be used. Or, as shown in FIG. 9, a rotating electric machine 100 with 32 poles and 192 slots may be used. In either case, the number of slots 28 per pole is six. Note that the electromagnetic coil 30 is omitted in FIGS. 8 and 9.

[0096] The greater the number of poles and slots 28, the greater the distance X from the center of rotation of the rotor 14 (center O of the rotating shaft 50) to the outer periphery of the stator core 20 tends to be. The outer diameter of the rotating electric machine 10 is twice the distance X, so in this case, the outer diameter is large. However, by setting the dimensions of each part or the intersection angle, etc., to the same numerical range as the rotating electric machine 10 illustrated in FIG. 1, it is possible to make the outer diameter of the rotating electric machines 90, 100 a maximum of 450 mm. Therefore, the rotating electric machines 90, 100 can also be made smaller and lighter.

[0097] Moreover, by setting the dimensions or intersection angles of each part to the same numerical range as the rotating electric machine 10 illustrated in Fig. 1, the rotational torque of the rotating shaft 50 can be improved. Therefore, the rotating electric machines 90, 100 can continuously output high torque. In other words, the rotating electric machines 90, 100 can also obtain the same effects as the rotating electric machine 10.

[0098] Instead of winding a wire around the teeth 26, a metal conductor as shown in FIG. 1 of JP 2020-39207 A may be used. This metal conductor has two legs. A predetermined number of the legs of the metal conductor are inserted into the slots 28 to form an electromagnetic coil.

[0099] The rotating electric machines 10, 90, 100 may function as generators. In this case, an alternating current is applied to the electromagnetic coil 30 from an external power source. [Explanation of symbols]

[0100] 10, 90, 100... Rotating electric machine 12... Stator 14... rotor 20... stator core 24...Yoke section 26...Teeth section 28...Slot 30...Electromagnetic coil 32…Shobbe 34…Tsubabe 36...expanded portion 40a...first parallel side 40b... second parallel side 42a... first inclined side 42b... second inclined side 44a... first radial side 44b... second radial side 50... rotating shaft 52...Rotor core 54...Permanent magnet 60, 601-604...Electromagnetic steel sheets 62...Inner ring portion 64...Outer ring part 66, 661~664...Connection part 70: First insertion hole 72: Through hole 74: Second insertion hole 76, 761-764: Hole group 80, 81...Plate group 82...Flow path LN1: First imaginary line LN2: Second imaginary line LN3: Third imaginary line LO: Total length of teeth OF: Offset amount α: Phase difference β, θ1, θ2…intersection angle

Claims

1. a stator having a stator core including a yoke portion having an annular shape and a plurality of teeth portions protruding from an inner peripheral edge of the yoke portion toward the inside in the radial direction of the yoke portion, with 96 to 192 slots formed between adjacent teeth portions in the plurality of teeth portions; a rotor disposed inside the stator and facing the plurality of teeth portions; A rotating electric machine comprising: The rotor has a rotor core that holds a permanent magnet with 16 to 32 poles, and a rotating shaft that rotates integrally with the rotor core, The rotor core is a laminate of a plurality of electromagnetic steel plates, Each of the plurality of electromagnetic steel plates is formed with a first insertion hole in which the rotating shaft is disposed, a plurality of through holes formed radially outward of the first insertion hole, and a plurality of second insertion holes formed radially outward of the plurality of through holes and into which the permanent magnets are inserted, each of the plurality of electromagnetic steel sheets has an inner annular portion located between the plurality of through holes and the first insertion hole, an outer annular portion located radially outward of the plurality of through holes and in which the plurality of second insertion holes are formed, and a plurality of connecting portions connecting the inner annular portion and the outer annular portion; The number of the plurality of connecting portions is 10 to 30, An intersection angle between adjacent connecting portions in the circumferential direction of the rotor is 12° to 36°, In the rotor core, the plurality of electromagnetic steel sheets are laminated in a first manner or a second manner, The first aspect is an aspect in which the plurality of electromagnetic steel sheets are stacked such that the plurality of connecting portions of one adjacent electromagnetic steel sheet in the plurality of electromagnetic steel sheets and the plurality of connecting portions of the other adjacent electromagnetic steel sheets in the plurality of electromagnetic steel sheets are not overlapped when the rotor is viewed in the axial direction of the rotor, The second aspect is an aspect in which a plurality of plate groups, each having a plurality of the electromagnetic steel plates, are stacked in the axial direction, and the plurality of connecting portions of one plate group adjacent to each other in the plurality of plate groups and the plurality of connecting portions of the other plate group adjacent to each other in the plurality of plate groups are stacked in positions that do not overlap when the rotor is viewed in the axial direction, When the number of poles is 16 to 24, the number of the slots is 96 to 144, the number of the plurality of connecting portions is 10 to 18, and the crossing angle is 36° to 20°; When the number of poles is 24 to 32, the number of the slots is 144 to 192, the number of the connecting portions is 18 to 30, and the crossing angle is 20° to 12°; The stator has an electromagnetic coil provided in the slot, Each of the plurality of teeth has a rod portion protruding radially inward from an inner peripheral edge of the yoke portion, a flange portion that is closer to the rotor than the rod portion and is wider than the rod portion, and an expansion portion that is interposed between the rod portion and the flange portion and that becomes wider from the rod portion toward the flange portion, a position of an inner peripheral end of the electromagnetic coil facing the rotor is offset from an inner peripheral end of the rod portion toward the yoke portion within the slot; The total length of the rod portion is 96% or more of the total length of the teeth portion, A rotating electric machine in which an offset amount, which is the distance from the inner peripheral end of the flange portion to the inner peripheral end of the electromagnetic coil, is 5% to 11% of the overall length of each of the plurality of teeth portions.

2. 2. The rotating electric machine according to claim 1, wherein an average number of said slots for one magnetic pole is six when said stator and said rotor are viewed in the axial direction of said stator.

3. 3. The rotating electric machine according to claim 1, wherein the outer diameter of the stator is within a range of 230 to 450 mm.

4. A rotating electric motor as described in any one of claims 1 to 3, wherein when the rotor inner diameter is twice the distance from the center of the first insertion hole to the inner peripheral edge of the inner annular portion and the rotor outer diameter is twice the distance from the center of the first insertion hole to the outer peripheral edge of the outer annular portion, the ratio of the rotor inner diameter to the rotor outer diameter is within the range of 1:1.5 to 1:3.

5.

5. A rotating electric motor as described in any one of claims 1 to 4, wherein the intersection angle between the shaft portion and the expansion portion is 108° to 130°, and the distance from the inner end to the outer end of the flange portion is 0.2 mm to 2.0 mm.

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