Rotating electrical machine

Abstract

A rotating electric machine is disclosed. A rotor (14) of a rotating electric machine (10) has a rotor core (52). The rotor core is a laminate of a plurality of electromagnetic steel sheets (60). In the electromagnetic steel sheets, a plurality of through holes (72) are formed between an inner annular portion (62) and an outer annular portion (64). The inner annular portion and the outer annular portion, which are separated by the through holes, are connected to each other at a plurality of connecting portions (66). An intersection angle (β) of one connecting portion and another connecting portion adjacent to the one connecting portion is in a range of 12° to 36°. Accordingly, the rotating electric machine can be lightened.

Description

Technical Field

[0001] This invention relates to a rotary electric motor having a stator and a rotor. Background Technology

[0002] A rotating electric motor has a stator and a rotor. The stator has multiple teeth. Slots are formed between adjacent teeth. Electromagnetic coils are placed in the slots. The rotor, on the other hand, has permanent magnets.

[0003] A rotary motor functions as, for example, an electric motor. In this case, an electromagnetic coil is energized. With the energization, the electromagnetic coil becomes magnetic, forming an alternating magnetic field. This alternating magnetic field and the magnetic field generated by a permanent magnet repel each other. Alternatively, the two magnetic fields attract each other. Through this repulsion and attraction, the rotor rotates.

[0004] Electric motors, for example, apply rotational driving force to rotating bodies. In the case of an aircraft propeller, the electric motor is required to continuously output high torque at low speeds during takeoff or hovering. To achieve this, the electric motor could be made larger. However, this increases the weight of the electric motor. Consequently, the aircraft also becomes larger and heavier.

[0005] Therefore, attempts are being made to achieve high torque while avoiding large-scale motors. For example, Japanese Patent Publication No. 2005-080381 proposes a structure that specifies the arc angle of the teeth facing the permanent magnet. Furthermore, Japanese Patent Publication No. 2005-080381 also illustrates a motor with 16 permanent magnets and 18 teeth. In this case, the number of teeth facing either the N or S pole of a single permanent magnet is approximately one.

[0006] Structures for obtaining high torque in electric motors are also proposed in Japanese Patent Publication No. 2007-151332 and Japanese Patent Publication No. 2007-209197. Summary of the Invention

[0007] To achieve further weight reduction in aircraft and other applications, it is necessary to further reduce the weight of electric motors. To address this requirement, for example, it is considered to form a so-called thin-walled portion on the rotor core. Specifically, multiple through holes are formed between a first insertion hole for inserting a rotating shaft and a second insertion hole for inserting a magnet. In this case, the rotor core has an inner ring portion, an outer ring portion, and a connecting portion. The inner ring portion is located on the inner circumference of the through holes and is where the first insertion hole is formed. The outer ring portion is located on the outer circumference of the through holes and is where the second insertion hole is formed. The connecting portion is located between adjacent through holes and connects the inner ring portion and the outer ring portion.

[0008] In this structure, to obtain high torque at low rotational speeds, it is necessary to increase the number of permanent magnets. Here, as mentioned above, the permanent magnets are held in the outer ring portion. Therefore, when the rigidity of the connection is low, there is a concern that the connection may bend due to the weight of the permanent magnets. For this reason, achieving a lightweight rotary motor that can obtain high torque is not easy.

[0009] The purpose of this invention is to solve the above-mentioned technical problems.

[0010] According to one embodiment of the present invention, a rotary motor is provided, the rotary motor having a stator and a rotor, wherein the stator has a yoke and a plurality of teeth, the yoke being annular in shape; the plurality of teeth protruding from the inner periphery of the yoke toward the radially inward side of the yoke, and adjacent teeth in the plurality of teeth forming slots between each other; the rotor is disposed inside the stator and faces the plurality of teeth, the rotor having a rotor core and a rotating shaft, wherein the rotor core holds permanent magnets with a pole number of 16 to 32; the rotating shaft and... The rotor core rotates integrally, and the rotor core is a stack of multiple electromagnetic steel plates. Each of the multiple electromagnetic steel plates has a first insertion hole, multiple through holes, and multiple second insertion holes. The first insertion hole is used to mount the rotating shaft. The multiple through holes are formed radially outside the first insertion hole. The multiple second insertion holes are formed radially outside the multiple through holes and are used to insert the permanent magnet. Each of the multiple electromagnetic steel plates has an inner ring portion, an outer ring portion, and multiple connecting portions. The inner ring portion is located between the plurality of through holes and the first insertion hole; the outer ring portion is located radially outside the plurality of through holes and forms the plurality of second insertion holes; the plurality of connecting portions connect the inner ring portion and the outer ring portion, and the 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 plates are stacked in a first manner or a second manner. The first manner is a stacking method in which the electromagnetic steel plates adjacent to each other are stacked in a certain way. The second method involves stacking multiple groups of plates, each having one of the multiple electromagnetic steel plates, along the axial direction, such that the multiple connecting portions of one adjacent group of plates and the multiple connecting portions of the other adjacent group of plates are located in positions that do not overlap when the rotor is viewed along the axial direction.

[0011] In this invention, the connecting portion is shaped like a windmill blade. Furthermore, the angle between one connecting portion and the adjacent connecting portion is specified within the range of 12° to 36°. By specifying the angle in this way, a connecting portion exhibiting sufficient rigidity can be obtained even when the number of poles is large, ranging from 16 to 32 poles (a large number of permanent magnets). Therefore, the connecting portion is less prone to bending. Additionally, the durability of the connecting portion is improved.

[0012] Furthermore, due to the large number of poles (16 to 32 poles, meaning a high number of permanent magnets), sufficient magnetic flux density can be obtained. Therefore, high torque can be achieved.

[0013] Furthermore, because multiple through holes are formed on the rotor core, the rotor core is lighter. Therefore, it is possible to achieve weight reduction in rotating electric machines.

[0014] The above-described objectives, features, and advantages should be readily understood through the description of the following embodiments with reference to the accompanying drawings. Attached Figure Description

[0015] Figure 1 This is a schematic horizontal cross-sectional view of the main parts of the rotary electric machine according to an embodiment of the present invention.

[0016] Figure 2 yes Figure 1 Enlarged view of the main parts.

[0017] Figure 3 This is a top-view overview of the rotor core.

[0018] Figure 4 This is a top view of the overall structure of one electromagnetic steel plate that forms the rotor core.

[0019] Figure 5 This is a three-dimensional exploded view of the main parts of the rotor core.

[0020] Figure 6 This is a three-dimensional exploded view of the main parts of another rotor core.

[0021] Figure 7 yes Figure 1 Enlarged view of the main parts.

[0022] Figure 8 This is a schematic horizontal cross-sectional view of the main parts of a rotary electric motor according to another embodiment of the present invention.

[0023] Figure 9 This is a schematic horizontal cross-sectional view of the main parts of the rotary electric motor according to another embodiment of the present invention. Detailed Implementation

[0024] Figure 1 This is a schematic horizontal cross-sectional view of the main parts of the rotary motor 10 according to this embodiment. The rotary motor 10 has: a stator 12, which is generally annular in shape; and a rotor 14, which is disposed inside the stator 12. The rotary motor 10 is, for example, a three-phase motor having a U-phase, a V-phase, and a W-phase.

[0025] First, the stator 12 will be described. The stator 12 has a stator core 20. The stator core 20 is, for example, a laminate made of magnetic materials such as electromagnet steel sheets.

[0026] The stator core 20 has a yoke 24 and a plurality of teeth 26. In this embodiment, the outer diameter of the rotary motor 10 is in the range of 230 mm to 450 mm. This outer diameter is smaller than that of a typical electric motor that rotates the propeller of an aircraft. That is, the rotary motor 10 is small. In addition, the outer diameter is equivalent to twice the distance X from the center O of the rotation shaft 50 to the outer periphery of the yoke 24.

[0027] The yoke 24 is in the shape of a ring. The tooth 26 protrudes from the inner periphery of the yoke 24 radially inward.

[0028] Slots 28 are formed between adjacent teeth 26. In the case that the rotary motor 10 is a three-phase motor, the number of slots 28 is typically a multiple of three. Figure 1 In the example shown, both the number of teeth 26 and slots 28 are 96. Furthermore, the number of poles (described later) is 16. Therefore, the rotary motor 10 is configured as a so-called 16-pole, 96-slot motor. An electromagnetic coil 30 is provided in slot 28. The electromagnetic coil 30 is, for example, made of copper wire. The electromagnetic coil 30 is obtained by winding the wire around the teeth 26.

[0029] Figure 2 yes Figure 1 Enlarged view of the main parts. One tooth 26 has a rod 32, a flange 34, and an extension 36. The rod 32 extends radially along the stator core 20. The flange 34 is located at the top of the inner circumference of the tooth 26. The extension 36 is located between the rod 32 and the flange 34.

[0030] The rod 32 has a first parallel side 40a and a second parallel side 40b. The distance W1 between the first parallel side 40a and the second parallel side 40b can also be referred to as the width dimension of the rod 32. The width direction is approximately orthogonal to the radial direction of the stator core 20.

[0031] The extension portion 36 gradually widens in width as it moves from the rod portion 32 toward the flange portion 34. In other words, the extension portion 36 is tapered toward the rod portion 32. The extension portion 36 has a first inclined edge 42a and a second inclined edge 42b. The first inclined edge 42a intersects the first parallel edge 40a of the rod portion 32 at an intersection angle θ1. The second inclined edge 42b also intersects the second parallel edge 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 making the intersection angles θ1 and θ2 within such a range, the total copper loss and iron loss in the stator 12 are reduced. Preferably, the intersection angles θ1 and θ2 are the same. However, the intersection angles θ1 and θ2 can also be different.

[0032] Let P1 be the intersection of the first parallel side 40a and the first inclined side 42a. Let P2 be the intersection of the second parallel side 40b and the second inclined side 42b. Let the straight line drawn from intersection P1 to intersection P2 be the first virtual straight line LN1. The first virtual straight line LN1 represents the inner peripheral end of the rod 32. At the same time, the first virtual straight line LN1 represents the outer peripheral end of the extension 36.

[0033] The first radial edge 44a of the flange portion 34 is connected to the first inclined edge 42a. The second radial edge 44b of the flange portion 34 is connected to the second inclined edge 42b. The first radial edge 44a and the second radial edge 44b are approximately straight and extend parallel to each other. Hereinafter, the interval between the first radial edge 44a and the second radial edge 44b is assumed to be W2. The interval 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.

[0034] Let the separation interval between adjacent flange portions 34 be G. Let the diameter of the wire forming the electromagnetic coil 30 be DM. The width W2 is, for example, within a range where the separation interval G is greater than the diameter DM. In this case, the magnetic flux saturation decreases at the flange portion 34. As a result, the rod portion 32 can accommodate a large amount of magnetic flux. Therefore, it is possible to increase the torque of the rotating shaft 50. In addition, the material of the stator core 20 (electromagnetic steel plate, etc.) can be selected from magnetic materials with low saturation magnetic flux density. Therefore, cost reduction is also possible.

[0035] Let P3 be the intersection point of the first inclined side 42a and the first radial side 44a. Intersection point P3 is the outer peripheral end of the first radial side 44a (the inner peripheral end of the first inclined side 42a). Let P4 be the intersection point of the second inclined side 42b and the second radial side 44b. Intersection point P4 is the outer peripheral end of the second radial side 44b (the inner peripheral end of the second inclined side 42b). Let the straight line drawn from intersection point P3 to intersection point P4 be the second virtual straight line LN2. The second virtual straight line LN2 represents the inner peripheral end of the extension portion 36 and the outer peripheral end of the flange portion 34.

[0036] Let the 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 be the third virtual straight line LN3. The third virtual straight line LN3 is the inner peripheral end of the flange portion 34. Let the distance between the third virtual straight line LN3 and the second virtual straight line LN2 be 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 will be defined as the thickness of the flange portion 34.

[0037] The preferred range for the thickness T1 of the flange portion 34 is 0.2 mm to 2.0 mm. A more preferred range for the thickness T1 is 0.3 mm to 1.1 mm. When the thickness T1 is within this range, the total copper loss and iron loss in the stator 12 are reduced.

[0038] The outer peripheral end of the rod 32 is connected to the inner peripheral edge of the yoke 24. The distance from the outer peripheral end of the rod 32 to the inner peripheral end of the flange 34 is defined as the total length LO of the tooth 26 (refer to...). Figure 2 In a typical example, the total length LO is in the range of 40mm to 45mm. Furthermore, in a typical example, when the total length LO is set to 100%, the total length of the rod 32 is more than 96%. In this case, the distance from the inner circumferential end of the flange 34 to the inner circumferential end of the rod 32 is less than 4% of the total length LO of the tooth 26.

[0039] 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 wire around the teeth 26. In this embodiment, distributed winding is performed. Figure 1 The example illustrates the so-called case of wrapping twice.

[0040] like Figure 2 As shown, in a cross-section perpendicular to the axial direction of the rotation axis 50, the inner circumferential end of the electromagnetic coil 30 is located within the slot 28. The inner circumferential end of the electromagnetic coil 30 is located between the inner circumferential end of the flange portion 34 and the outer circumferential end of the rod portion 32. Therefore, the inner circumferential end of the electromagnetic coil 30 is offset towards the yoke portion 24 (the outer circumference of the stator core 20). Figure 2 In this configuration, the inner circumferential end of the electromagnetic coil 30 is located between the outer circumferential end of the extension portion 36 (the inner circumferential end of the rod portion 32) and the outer circumferential end of the rod portion 32. The distance from the inner circumferential end of the flange portion 34 to the inner circumferential end of the electromagnetic coil 30 is defined as the offset OF. A preferred range of the offset OF is 5% to 11% of the total length LO of the tooth portion 26. For example, when the total length LO is 40 mm, a suitable offset OF is 2 mm to 4.4 mm. A more preferred range of the offset OF is 5.6% to 10.3% of the total length LO of the tooth portion 26.

[0041] When the offset OF is less than 5% of the total length LO of the tooth 26, the winding amount of the electromagnetic coil 30 increases. Therefore, the volume of the electromagnetic coil 30 increases. As a result, the magnetic flux received from the permanent magnet 54 of the rotor 14 increases. Therefore, there is concern that the heat generated by the electromagnetic coil 30 increases. Additionally, copper losses increase. When the offset OF exceeds 11%, copper losses decrease. However, the exposed area of ​​the rod 32 increases, thus iron losses increase. As a result, heat generation increases. Furthermore, since the winding amount of the electromagnetic coil 30 decreases, the volume of the electromagnetic coil 30 decreases. Therefore, the output of the rotary motor 10 as a motor decreases.

[0042] When the total length LO of the tooth 26 is 40mm to 45mm, the specific distance from the first virtual straight line LN1 to the inner peripheral end of the electromagnetic coil 30 is typically 1 to 3mm. As described above, the first virtual straight line LN1 is the inner peripheral end of the rod 32 and the outer peripheral end of the extension 36.

[0043] The rotor 14 will be described below. Figure 1 As shown, rotor 14 is disposed inside tooth 26.

[0044] Rotor 14 has a rotating shaft 50, a rotor core 52, and multiple (in) Figure 1 (In this example, there are 32) permanent magnets 54. The rotor core 52 rotates integrally with the rotating shaft 50. The permanent magnets 54 are held in the rotor core 52. Therefore, when the rotating shaft 50 rotates, the permanent magnets 54 move along the outer periphery of the rotor core 52.

[0045] like Figure 3 As shown, the rotor core 52 has multiple electromagnetic steel plates 60. The rotor core 52 is formed by stacking multiple electromagnetic steel plates 60. That is, the rotor core 52 is a stack of multiple electromagnetic steel plates 60.

[0046] like Figure 4 As shown, an electromagnetic steel plate 60 is a thin-walled annular shape. The electromagnetic steel plate 60 has an inner annular portion 62 located on its inner circumference and an outer annular portion 64 located on its outer circumference. The inner annular portion 62 and the outer annular portion 64 are approximately annular in shape and are concentric circles. The inner annular portion 62 and the outer annular portion 64 are connected by multiple (in...) Figure 4 In this example, there are 10 connecting parts 66 connected together. In this way, the connecting parts 66 connect the outer periphery of the inner ring part 62 and the inner periphery of the outer ring part 64.

[0047] A circular first insertion hole 70 is formed in the inner ring portion 62. Figure 1 The rotating shaft 50 shown passes through the first insertion hole 70. The center O of the rotating shaft 50 coincides with the center of the first insertion hole 70.

[0048] Let Rin be the distance from the center O to the inner periphery of the inner ring 62 (refer to...). Figure 3 When Rin is twice the inner diameter of the rotor core 52, and Rout is the distance from the center O to the outer periphery of the outer ring 64, 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 greater than the rotor inner diameter.

[0049] Preferably, the rotor outer diameter is 1.5 to 3.5 times the rotor inner diameter. That is, preferably, the ratio of the rotor inner diameter to the rotor outer diameter is in the range of 1:1.5 to 1:3.5. In this case, Rin:Rout = 1:1.5 to 3.5 holds true.

[0050] Adjacent connecting portions 66 form through holes 72 between each other. A plurality of second insertion holes 74 are formed in the outer ring portion 64 (in... Figure 4 (In this example, there are 32). One second insertion hole 74 is rectangular. Two second insertion holes 74 are close to each other and form a group. Hereinafter, a group of second insertion holes 74 (two second insertion holes 74 that are close to each other) is referred to as "hole group 76". The spacing between adjacent hole groups 76 is greater than the spacing between the second insertion holes 74 in a single hole group 76. In this case, the spacing angle (phase difference) α between adjacent hole groups 76 is 22.5°.

[0051] A permanent magnet 54 is inserted into the second insertion hole 74. Since there are 32 second insertion holes 74, there are also 32 permanent magnets 54. Two permanent magnets 54 are inserted into a group of holes 76 with the same magnetic pole facing outwards. Figure 3 In the diagram, the N pole of the permanent magnet 54 is represented by a grid. In contrast, the S pole is not represented by a grid. The same applies in the subsequent figures.

[0052] As by Figure 3 As understood, in any group of holes 76, the N poles of the two permanent magnets 54 face outwards. In this case, in the group of holes 76 adjacent to this group, the S poles of the two permanent magnets 54 face outwards. In the following description, when simply referred to as "N pole" or "S pole," it indicates the magnetic pole facing outwards. In the stator 12, the two S poles are located between the two N poles and two other N poles.

[0053] Below, the same magnetic pole facing outwards from the two permanent magnets 54 housed in a group of holes 76 is considered as one pole. That is, two adjacent N poles in a group of holes 76 are one pole. Similarly, two adjacent S poles in another group of holes 76 are also one pole. In this embodiment, 16 groups of holes 76 are formed. Therefore, the number of magnetic poles is 16. Thus, the rotary motor 10 is a 16-pole 3-phase motor. In this specification, the number of magnetic poles thus determined is defined as the "number of poles".

[0054] A connecting portion 66 extends from the outer periphery of the inner ring portion 62 to the inner periphery of the outer ring portion 64. The extending direction of the connecting portion 66 is inclined relative to the diameter of the electromagnetic steel plate 60. (See the example in the figure.) Figure 4 In this diagram, there are 10 connecting parts 66. Therefore, the intersection angle β between adjacent connecting parts 66 is 36°.

[0055] However, the number of connecting portions 66 is not limited to 10. Therefore, the cross angle β is not limited to 36°. The preferred number of connecting portions 66 is 10 to 30. The preferred range of the cross angle β is 12° to 36°. When the cross angle β is within such a range, the connecting portion 66 exhibits sufficient rigidity. Therefore, bending of the connecting portion 66 due to the combined weight of the outer ring portion 64 and the permanent magnet 54 is avoided.

[0056] In particular, the more permanent magnets 54 (or poles) there are, the more likely the number of connecting parts 66 will be increased. For example, when the number of poles is 32, it is more suitable to have 30 connecting parts 66. In this case, the intersection angle β between adjacent connecting parts 66 is 12°. When the number of poles is 24, it is more suitable to have 18 connecting parts 66. In this case, the intersection angle β between adjacent connecting parts 66 is 20°.

[0057] Figure 5 This is an exploded perspective view of the main components of the rotor core 52. Figure 5 The image shows four electromagnetic steel plates, each 60 cm in size. For ease of understanding, let's assume... Figure 5 The lowest electromagnet plate 60 is designated as the first electromagnet plate 601. The hole group 76 of the first electromagnet plate 601 is designated as the first hole group 761, and the connecting portion 66 of the first electromagnet plate 601 is designated as the first connecting portion 661. The electromagnet plate 60 stacked above and adjacent to the first electromagnet plate 601 is designated as the second electromagnet plate 602. The hole group 76 of the second electromagnet plate 602 is designated as the second hole group 762, and the connecting portion 66 of the second electromagnet plate 602 is designated as the second connecting portion 662. The electromagnet plate 60 stacked above and adjacent to the second electromagnet plate 602 is designated as the third electromagnet plate 603. The hole group 76 of the third electromagnet plate 603 is designated as the third hole group 763, and the connecting portion 66 of the third electromagnet plate 603 is designated as the third connecting portion 663. Let the electromagnetic steel plate 60 stacked above and adjacent to the third electromagnetic steel plate 603 be called the fourth electromagnetic steel plate 604. Let the hole group 76 of the fourth electromagnetic steel plate 604 be called the fourth hole group 764, and let the connecting part 66 of the fourth electromagnetic steel plate 604 be called the fourth connecting part 664.

[0058] The second electromagnetic plate 602 is stacked on the first electromagnetic plate 601 with a 45° rotation relative to the first electromagnetic plate 601. In this case, a 9° phase difference is generated between the first connecting portion 661 and the second connecting portion 662. Furthermore, the first hole group 761 and the second hole group 762 coincide. In other words, the first hole group 761 and the second hole group 762 are interconnected.

[0059] The third electromagnetic plate 603 is stacked on the second electromagnetic plate 602 with a 45° rotation relative to the second electromagnetic plate 602 and a 90° rotation relative to the first electromagnetic plate 601. In this case, a 9° phase difference is generated between the second connecting portion 662 and the third connecting portion 663, and an 18° phase difference is generated between the first connecting portion 661 and the third connecting portion 663. In addition, the third hole group 763 communicates with the first hole group 761 and the second hole group 762.

[0060] The fourth electromagnetic plate 604 is stacked on the third electromagnetic plate 603 with a rotation of 45° relative to the third electromagnetic plate 603, a rotation of 90° relative to the second electromagnetic plate 602, and a rotation of 135° relative to the first electromagnetic plate 601. In this case, a 9° phase difference is generated between the third connecting portion 663 and the fourth connecting portion 664, an 18° phase difference is generated between the second connecting portion 662 and the fourth connecting portion 664, and a 27° phase difference is generated between the first connecting portion 661 and the fourth connecting portion 664. In addition, the fourth hole group 764 communicates with the first hole group 761, the second hole group 762, and the third hole group 763.

[0061] The combination of the first to fourth electromagnetic steel plates 601 to 604 constitutes a plate group 80. Another plate group 80 is stacked on top of the first plate group 80. Therefore, the first electromagnetic steel plate 601 of the other plate group 80 is stacked above the fourth electromagnetic steel plate 604 in the first plate group 80, adjacent to the fourth electromagnetic steel plate 604. When the rotor 14 is viewed along its axial direction, the positions of the first hole group 761 and the first connecting portion 661 on the first electromagnetic steel plate 601 in the lower plate group 80 correspond to the positions of the first hole group 761 and the first connecting portion 661 on the first electromagnetic steel plate 601 in the upper plate group 80 (they coincide with each other).

[0062] When the rotor 14 is viewed along its axial direction, the first group of holes 761, the second group of holes 762, the third group of holes 763, and the fourth group of holes 764 are all connected. The permanent magnet 54 passes through all the groups of holes 76 along the stacking direction of the electromagnet plates 60. In addition, the inner ring portions 62 of the first to fourth electromagnet plates 601 to 604 completely overlap each other.

[0063] In contrast, when the rotor 14 is viewed along its axial direction, the second connecting portion 662, the third connecting portion 663, and the fourth connecting portion 664 are located between adjacent first connecting portions 661. A gap is formed between the first connecting portion 661 and the second connecting portion 662. A gap is also formed between the second connecting portion 662 and the third connecting portion 663. A gap is also formed between the third connecting portion 663 and the fourth connecting portion 664. A gap is also formed between the fourth connecting portion 664 and the first connecting portion 661. Therefore, the through holes 72 between adjacent first connecting portions 661 are not closed by the second connecting portion 662, the third connecting portion 663, and the fourth connecting portion 664.

[0064] Therefore, in the rotor core 52, a portion of the through holes 72 overlap each other along the stacking direction of the electromagnetic steel plates 60. In this way, the through holes 72 are connected, and based on this, as... Figure 3 As shown, a flow path 82 (through hole 72) is formed in the rotor core 52 along the stacking direction of the electromagnetic steel plate 60.

[0065] like Figure 6 As shown, a group of plates 81 can also be formed by stacking multiple electromagnetic steel plates 60 in a phase where all the connecting portions 66 overlap each other. In this case, when another group of plates 81 is stacked above and adjacent to the group of plates 81, the connecting portions 66 of the lower group of plates 81 and the connecting portions 66 of the upper group of plates 81 are in a phase that does not overlap. For example, a 9° phase difference is set between the connecting portions 66 of the lower group of plates 81 and the connecting portions 66 of the upper group of plates 81. The next stacked group of plates 81 is also in a phase where the connecting portions 66 of this group of plates 81 do not overlap with the connecting portions 66 of the two already stacked groups of plates 81 (there is a 9° phase difference). The next stacked group of plates 81 is also in a phase where the connecting portions 66 of this group of plates 81 do not overlap with the connecting portions 66 of the three already stacked groups of plates 81 (there is a 9° phase difference). The above stacking can also be repeated. In either case, when the rotor 14 is viewed along the axial direction of the rotor 14, it is... Figure 3 The shape shown is obtained. That is, the rotor core 52 is obtained.

[0066] As described above, the two permanent magnets 54 disposed in the group of holes 76 are either N poles or S poles. That is, the number of poles of the permanent magnets 54 in the group of holes 76 is 1. The two permanent magnets 54 face the rod portion 32 across the flange portion 34. In this embodiment, the number of poles is 16, and the number of teeth 26 is 96. Therefore, the average number of teeth 26 corresponding to the 1 pole (in this embodiment, the two permanent magnets 54 disposed in the group of holes 76) is 6.

[0067] There are 96 teeth 26, therefore, there are also 96 slots 28. Therefore, the average number of slots 28 corresponding to pole 1 is also 6 (see reference). Figure 7 Thus, the average number of teeth 26 or slots 28 corresponding to the magnetic pole of pole 1 can be calculated.

[0068] exist Figure 7 The image shows the moment when one magnetic pole (two permanent magnets 54 disposed in a group of holes 76) faces the six slots 28. In this case, approximately half of the tooth 26 faces the lower S pole, and approximately half of the other tooth 26 faces the upper S pole. Furthermore, all five teeth 26 face the two S poles. Therefore, in this case, the average number of teeth 26 facing the two S poles is also six.

[0069] Additionally, when rotor 14 from Figure 7 When the state is slightly rotated, the six teeth 26 are positioned facing each other in the middle of the two permanent magnets 54 located in a group of holes 76. Additionally, approximately half of one slot 28 faces the lower S pole, and approximately half of another slot 28 faces the upper S pole. Furthermore, five slots 28 are generally aligned with the two S poles. Therefore, in this configuration, the average number of slots 28 facing the two S poles is also six.

[0070] The rotor 14 has a rotating shaft 50. This rotating shaft 50 is rotatably supported by a support member (not shown). A bearing (not shown) is disposed on the rotating shaft 50. This bearing is located between the rotating shaft 50 and the support member.

[0071] A rotating body (not shown) is mounted at the top of the rotating shaft 50. The rotating shaft 50 and the rotating body can also be connected by gears or the like. In either case, the rotating body rotates as the rotating shaft 50 is rotated by energizing the electromagnetic coil 30. The rotating body can be, for example, a propeller.

[0072] The rotary motor 10 described in this embodiment is basically configured as described above. Next, the effects of the rotary motor 10 will be explained.

[0073] As described above, the rotor core 52 is formed by stacking multiple electromagnetic steel plates 60. Each electromagnetic steel plate 60 has a through hole 72 formed therein. Therefore, each electromagnetic steel plate 60 is lightweight. Therefore, the rotor core 52 is lightweight. Therefore, the rotary motor 10 is also lightweight.

[0074] Furthermore, as described above, in this embodiment, the outer diameter of the rotary motor 10 is at most 450 mm. That is, the rotary motor 10 is relatively small. Thus, according to this embodiment, miniaturization and weight reduction of the rotary motor 10 can be achieved.

[0075] The rotary motor 10 is used, for example, as a rotational drive source for the propeller of an aircraft. In this case, the rotary motor 10 is used as a three-phase electric motor.

[0076] To enable the rotary motor 10 to function as a three-phase motor, the electromagnetic coil 30 is energized. With this energization, the electromagnetic coil 30 generates an alternating magnetic field. This alternating magnetic field either repels or attracts the magnetic field of the permanent magnet 54. Consequently, the rotating shaft 50 and the rotor core 52 rotate as a unit. Therefore, the permanent magnet 54 moves in a circular motion along the outer edge of the rotor core 52.

[0077] To obtain high torque at low rotational speeds of the rotating shaft 50, a large-diameter bearing is required. The rotor inner diameter is set to a size capable of supporting a large-diameter bearing. Here, when the ratio of the rotor inner diameter to the rotor outer diameter is in the range of 1:1.5 to 1:3.5, it is possible to prevent the diameter of the electromagnetic steel plate 60 (the diameter of the rotor 14) from becoming too large. Therefore, under these conditions, the rotor 14, although small, can support a large-diameter bearing.

[0078] Each electromagnet plate 60 of the rotor core 52 has a connecting portion 66. The intersection angle β between adjacent connecting portions 66 is in the range of 12° to 36°. Accordingly, a suitable number of connecting portions 66 are specified. Thus, the outer ring portion 64 is firmly supported to the inner ring portion 62 by the connecting portions 66. Accordingly, multiple permanent magnets 54 can be held by the rotor core 52. That is, the number of poles can be increased. Therefore, the torque of the rotating shaft 50 can be increased.

[0079] exist Figure 1 In the example, the number of magnetic poles is 16, and the number of slots 28 is 96. Therefore, the number of slots 28 facing the first magnetic pole (the two permanent magnets 54 inserted into a group of holes 76) is 6. Thus, in this embodiment, the number of slots 28 facing the first magnetic pole is suitably specified. Accordingly, although the diameter of the rotary motor 10 is relatively small, the torque of the rotating shaft 50 is also increased. That is, although the rotary motor 10 is a small and lightweight 3-phase motor, it is able to apply a large rotational driving force to rotating bodies such as propellers.

[0080] Furthermore, under these conditions, leakage flux decreases. As a result, the linkage flux of the electromagnetic coil 30 decreases. Therefore, the eddy current in the electromagnetic coil 30 decreases, thereby suppressing the heating of the electromagnetic coil 30.

[0081] Furthermore, the intersection angles θ1 and θ2 between the tooth portion 26, the rod portion 32, and the extension portion 36 are in the range of 108° to 130°. The thickness T1 of the flange portion 34 is in the range of 0.2 mm to 2.0 mm. The offset OF of the electromagnetic coil 30 relative to the tooth portion 26 is in the range of 5% to 11%. By keeping the intersection angle θ, thickness T1, and offset OF within such ranges, the combined iron loss and copper loss in the stator 12 can be reduced. Therefore, the heating of the stator 12 can be suppressed.

[0082] Furthermore, by appropriately setting the offset OF, the leakage flux is reduced. This prevents localized temperature rises, such as in the tooth section 26 or the electromagnetic coil 30. Therefore, it can suppress the degradation of the materials (electromagnetic steel plate 60, etc.) of the stator core 20 or the electromagnetic coil 30 (copper, etc.) caused by such temperature rises.

[0083] As described above, according to this embodiment, it is possible to simultaneously reduce the size and weight of the rotary motor 10 while increasing the torque of the rotating shaft 50. Therefore, when the rotary motor 10 is used as an electric motor, it can continuously output high torque. Furthermore, as described above, heat generation in the rotary motor 10 is suppressed.

[0084] A cooling medium (e.g., cooling air) is supplied to the rotary motor 10. A portion of the cooling medium passes between the stator core 20 and the rotor core 52. Another portion of the cooling medium passes through a flow path 82 (through hole 72) formed in the rotor core 52. In this way, the rotary motor 10 is cooled.

[0085] In the rotor core 52, a phase difference is established between one electromagnetic steel plate 60 and the electromagnetic steel plate 60 stacked above and adjacent to it. Therefore, a phase difference is also generated between the through holes 72 in the two stacked electromagnetic steel plates 60. This prevents the cooling medium from concentrating or stagnating in a single flow path 82 within the rotor core 52. In other words, the cooling medium is distributed approximately equally among the multiple flow holes, and the distributed cooling medium then easily passes through each flow hole. Therefore, the rotating motor 10 as a whole is cooled efficiently and approximately evenly.

[0086] As the rotor core 52 rotates, it is subjected to stress. Here, a phase difference also arises between the connecting portions 66 of the two stacked electromagnet plates 60. Therefore, the stress is distributed among the connecting portions 66 that generate the phase difference. This prevents stress concentration at any single connecting portion 66. For this reason, the durability of the connecting portions 66 is improved.

[0087] As described above, this embodiment discloses a rotary motor (10) having a stator (12) and a rotor (14). The stator (12) has a yoke (24) and a plurality of teeth (26). The yoke (24) is annular in shape. The plurality of teeth (26) protrude radially inward from the inner periphery of the yoke. Adjacent teeth in the plurality of teeth form grooves (28) between each other. The rotor (14) is disposed inside the stator and faces the plurality of teeth. The rotor has a rotor core (52) and a rotating shaft (50). The rotor core (52) holds permanent magnets (54) with a pole number of 16 to 32. The rotating shaft (50) rotates integrally with the rotor core. The rotor core is a stack of a plurality of electromagnetic steel plates (60). A first insertion hole (70) and a plurality of through holes (7) are formed on each of the plurality of electromagnetic steel plates. 2) and a plurality of second insertion holes (74), wherein the first insertion hole (70) is used to configure the rotating shaft; the plurality of through holes (72) are formed radially outside the first insertion hole; the plurality of second insertion holes (74) are formed radially outside the plurality of through holes and the permanent magnet is inserted therein, and each of the plurality of electromagnetic steel plates has an inner ring portion (62), an outer ring portion (64) and a plurality of connecting portions (66), wherein the inner ring portion (62) is located between the plurality of through holes and the first insertion hole; the outer ring portion (64) is located radially outside the plurality of through holes and has the plurality of second insertion holes; the plurality of connecting portions (66) connect the inner ring portion and the outer ring portion, and the cross angle (β) of the connecting portions of the plurality of connecting portions adjacent to each other in the circumferential direction of the rotor is 12° to 36°, and in the rotor core, the plurality of electromagnetic steel plates are stacked in a first manner or a second manner.

[0088] The first method is to stack the electromagnetic plates in such a way that the plurality of connecting portions (661) of one of the plurality of electromagnetic plates adjacent to each other and the plurality of connecting portions (662) of the other of the plurality of electromagnetic plates adjacent to each other are located in a position that does not overlap when the rotor is viewed along the axial direction of the rotor.

[0089] The second method is to stack multiple plates (81) having the multiple electromagnetic steel plates in a manner that is as follows: multiple plate groups (81) are stacked along the axial direction, and the multiple connecting portions (661) of one of the multiple plate groups adjacent to each other and the multiple connecting portions (662) of the other of the multiple plate groups adjacent to each other are located in a position that does not overlap when the rotor is viewed along the axial direction.

[0090] In this rotary motor, the connecting part is shaped like a windmill blade. Furthermore, in a single electromagnetic steel plate, the angle between one connecting part and the adjacent connecting part is specified to be within the range of 12° to 36°. By specifying the angle in this way, a connecting part exhibiting sufficient rigidity can be obtained even with a large number of poles (16 to 32 poles, or a large number of permanent magnets). Therefore, the connecting part is less prone to bending. Additionally, the durability of the connecting part is improved.

[0091] Furthermore, due to the large number of poles (16 to 32 poles, meaning a high number of permanent magnets), sufficient magnetic flux density can be obtained. Therefore, high torque can be achieved.

[0092] Furthermore, because multiple through holes are formed in the rotor core, the rotor core is lighter. Therefore, a lighter rotary electric motor can be achieved. For the reasons stated above, a lighter rotary electric motor can be achieved while still obtaining sufficiently high torque.

[0093] To obtain a rotor core with significant thickness as a single component, it is necessary to form the first insertion hole, through hole, and second insertion hole by piercing a cylindrical workpiece, for example. However, piercing a thick workpiece is not easy. In contrast, when the rotor core is obtained by stacking electromagnetic steel sheets of the aforementioned shape, the first insertion hole, through hole, and second insertion hole are formed simply by stacking the electromagnetic steel sheets.

[0094] For example, each electromagnetic steel plate is obtained by stamping a thin-walled, circular plate-shaped workpiece to form a first insertion hole, a through hole, and a second insertion hole. Stamping a thin-walled, circular plate-shaped workpiece is easier to perform than piercing a thick workpiece. Therefore, the rotor core can be easily manufactured.

[0095] In a stacked network of two (or two groups of) electromagnetic steel plates, the connecting parts do not overlap, thus avoiding stress concentration at the connecting parts in any phase. That is, stress is appropriately distributed to the connecting parts with different phases. Therefore, the durability of the connecting parts is improved.

[0096] This embodiment discloses a rotary motor in which, when the stator and the rotor are viewed along the axial direction of the stator, the average number of slots corresponding to the 1st pole is 6.

[0097] In this case, the average number of slots and teeth facing the first pole is appropriately specified. Accordingly, even when the diameter of the rotary motor is relatively small, the torque of the rotating shaft increases. Therefore, when using the rotary motor as a three-phase motor, despite its small size and light weight, a large rotational driving force can be applied to the rotating body mounted on the rotating shaft. That is, the rotary motor can continuously output high torque.

[0098] Furthermore, in this situation, leakage flux decreases. As a result, the linkage flux of the electromagnetic coil decreases. Therefore, the eddy current in the electromagnetic coil decreases, and the heating of the electromagnetic coil is suppressed.

[0099] In addition, the number of poles and slots are specified as described above. In this case, it is possible to obtain a large torque on the rotating shaft while avoiding an excessively large diameter of the rotary motor. Therefore, a small but high-output motor can be obtained.

[0100] This embodiment discloses a rotary electric motor, wherein the outer diameter of the stator is in the range of 230 to 450 mm. Furthermore, "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, "outer diameter of the stator" can also be referred to as "outer diameter of the rotary electric motor."

[0101] This type of rotary motor has a relatively small outer diameter. That is, the rotary motor is small but can continuously output high torque.

[0102] Furthermore, the present invention is not limited to the embodiments described above, and various structures can be adopted without departing from the spirit of the present invention.

[0103] The above embodiment exemplifies a 16-pole, 96-slot rotary motor 10. However, the number of poles or slots 28 is not particularly limited thereto. For example, as... Figure 8 As shown, it could also be a 24-pole, 144-slot rotary motor 90. Or, as... Figure 9 As shown, it can also be a 32-pole, 192-slot rotary motor 100. In either case, the number of slots 28 corresponding to 1 pole is 6. Additionally, in Figure 8 and Figure 9 The electromagnetic coil 30 is omitted from the text.

[0104] The greater the number of poles and slots 28, the greater the tendency for the distance X from the rotation center of rotor 14 (center O of rotation shaft 50) to the outer periphery of stator core 20 to be. Since twice the distance X is the outer diameter of the rotary motor 10, the outer diameter becomes larger in this case. However, by adjusting the dimensions of each part or the cross angle, etc., to... Figure 1 With the same numerical range as the rotary motor 10 shown, the maximum outer diameter of the rotary motors 90 and 100 is 450 mm. Therefore, the rotary motors 90 and 100 can also be miniaturized and lightweight.

[0105] Furthermore, by adjusting the dimensions or intersection angles of each part to match... Figure 1The same numerical range as the example rotary motor 10 can increase the torque of the rotating shaft 50. Therefore, according to the rotary motors 90 and 100, high torque can be continuously output. That is, the same effect as that of the rotary motor 10 can be obtained in the rotary motors 90 and 100.

[0106] Alternatively, Japanese Patent Publication No. 2020-39207 can be used instead of winding wire around the teeth 26. Figure 1 The metal conductor shown has two legs. An electromagnetic coil is formed by inserting a predetermined number of the metal conductor legs into slot 28.

[0107] The rotary motors 10, 90, and 100 can also function as generators. In this case, an alternating current is applied to the electromagnetic coil 30 by an external power source.

Claims

1. A rotary electric motor (10) having a stator (12) and a rotor (14), wherein, The stator (12) has a yoke (24) and a plurality of teeth (26), the yoke (24) being annular in shape; the plurality of teeth (26) protruding from the inner periphery of the yoke toward the radially inner side of the yoke, wherein adjacent teeth in the plurality of teeth form 96 to 192 slots (28) between each other, and the stator (12) has a stator core (20). The rotor (14) is disposed inside the stator and faces the plurality of teeth; The rotary electric motor is characterized in that, The rotor has a rotor core (52) and a rotating shaft (50), wherein the rotor core (52) holds permanent magnets (54) with a pole number of 16 to 32; the rotating shaft (50) rotates integrally with the rotor core. The rotor core is a stack of multiple electromagnetic steel plates (60). Each of the plurality of electromagnetic steel plates has a first insertion hole (70), a plurality of through holes (72), and a plurality of second insertion holes (74), wherein the first insertion hole (70) is used to arrange the rotating shaft; the plurality of through holes (72) are formed radially outside the first insertion hole; and the plurality of second insertion holes (74) are formed radially outside the plurality of through holes and the permanent magnet is inserted therein. Furthermore, each of the plurality of electromagnetic steel plates has an inner ring portion (62), an outer ring portion (64), and a plurality of connecting portions (66), wherein the inner ring portion (62) is located between the plurality of through holes and the first insertion hole; the outer ring portion (64) is located radially outside the plurality of through holes and forms the plurality of second insertion holes; the plurality of connecting portions (66) connect the inner ring portion and the outer ring portion. The number of the plurality of connecting parts is 10 to 30. The intersection angle (β) of adjacent connecting parts in the circumferential direction of the rotor is 12° to 36°. In the rotor core, multiple electromagnetic steel plates are stacked in either the first or the second manner. The first method involves stacking the electromagnetic plates in such a way that the plurality of connecting portions (661) of one of the plurality of electromagnetic plates adjacent to each other and the plurality of connecting portions (662) of the other of the plurality of electromagnetic plates adjacent to each other are located in a position that does not overlap when the rotor is viewed along the axial direction of the rotor. The second method involves stacking multiple groups of plates (81) each having a plurality of electromagnetic steel plates along the axial direction, wherein the plurality of connecting portions (661) of one adjacent group of plates and the plurality of connecting portions (662) of the other adjacent group of plates are located in positions that do not overlap when the rotor is viewed along the axial direction. When the number of poles is 16 to 24, the number of slots is 96 to 144, the number of multiple connecting parts is 10 to 18, and the intersection angle is 36° to 20°. When the number of poles is 24 to 32, the number of slots is 144 to 192, the number of multiple connecting parts is 18 to 30, and the intersection angle is 20° to 12°. The stator has an electromagnetic coil (30) disposed in the slot. The plurality of teeth each have a shank (32), a flange (34), and an extension (36), wherein the shank (32) protrudes radially inward from the inner periphery of the yoke, the flange (34) is closer to the rotor than the shank and is wider than the shank, and the extension (36) is located between the shank and the flange, and its width increases as it moves from the shank toward the flange. The position of the electromagnetic coil facing the inner circumferential end of the rotor is offset within the slot from the inner circumferential end of the rod towards the yoke. The total length of the rod portion is more than 96% of the total length of the tooth portion. The distance, or offset, from the inner circumferential end of the flange to the inner circumferential end of the electromagnetic coil is 5% to 11% of the total length of each of the plurality of teeth.

2. The rotary motor according to claim 1, characterized in that, When the stator and the rotor are viewed along the axial direction of the stator, the average number of slots corresponding to the magnetic pole of pole 1 is 6.

3. The rotary motor according to claim 1, characterized in that, The outer diameter of the stator is in the range of 230 to 450 mm.

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