JP2023049628A - Rotary electric machine - Google Patents

Abstract

To provide a motor capable of obtaining sufficiently large running torque even in a case where a rotary shaft is rotated at a low speed, and suppressing generation of heat from a stator (especially an electromagnetic coil).SOLUTION: A stator 12 of a rotary electric machine 10 comprises a yoke 24 and a plurality of teeth 26. Each of the plurality of teeth includes a rod part 32 protruding radially inside of the yoke and a flange part 34 wider than the rod part. An expanded part 36 is provided between the rod part and the flange part. The expanded part becomes wider gradually in a direction from the rod part to the flange part. Crossing angles θ1 and θ2 of the rod part and the expanded part ranges from 108° to 130°. A distance T1 from an inner peripheral end to an outer peripheral end of the flange part ranges from 0.2 mm to 2.0 mm.SELECTED DRAWING: Figure 2

Description

The present invention relates to a rotating electrical machine that includes a stator and a rotor.

A rotating electrical machine includes a stator and a rotor. The stator has a plurality of teeth. A slot is formed between adjacent tooth portions. An electromagnetic coil is provided in the slot. On the other hand, the rotor has permanent magnets.

A rotating electrical machine functions, for example, as a motor. In this case, the electromagnetic coil is energized. As the power is supplied, the electromagnetic coil becomes magnetized and an alternating magnetic field is formed. This alternating magnetic field and the magnetic field of the permanent magnet repel each other. Alternatively, the two magnetic fields attract each other. The rotor rotates due to the above repulsion and attraction.

The motor, for example, imparts rotational driving force to the rotating body. When the rotating body is a propeller of a flying object, the motor is required to have a performance capable of continuously outputting high torque at low rotation when the flying object takes off or hovers. In order to obtain this performance, it is conceivable to increase the size of the motor. However, in this case, the weight of the motor increases. Therefore, the flying object also becomes large and heavy.

Therefore, attempts have been made to obtain high torque while avoiding the need for a large motor. For example, Patent Literature 1 proposes a structure in which the arc angle of teeth facing a permanent magnet is defined. Note that Patent Document 1 exemplifies a motor having 16 permanent magnets and 18 tooth portions. In this case, the number of tooth portions facing the N pole or S pole of one permanent magnet is approximately one.

Patent document 2 and patent document 3 also propose a structure for obtaining high torque in a motor.

Japanese Patent Application Laid-Open No. 2005-80381 JP 2007-151332 A JP 2007-209197 A

In order to further reduce the size and weight of flying objects, there is a demand for further miniaturization of motors. However, it is not easy to obtain high torque with a small motor.

In order to obtain high torque even with a small size, it is conceivable to increase the number of permanent magnets. However, in this case, the amount of magnetic flux from the permanent magnet increases. If the stator cannot sufficiently accommodate this amount of flux, a so-called leakage flux will occur. Leakage magnetic flux contributes to the heat generation of the stator (particularly the electromagnetic coil). Moreover, when the rotating electric machine is made to function as a generator, there is a possibility that the amount of power generation will be reduced. Thus, leakage magnetic flux causes various inconveniences.

An object of the present invention is to solve the problems described above.

According to one embodiment of the present invention, a yoke portion having an annular shape and a plurality of tooth portions protruding radially inwardly of the yoke portion from an inner peripheral edge of the yoke portion are provided, and the plurality of tooth portions a stator in which slots are formed between tooth portions adjacent to each other in the tooth portions;
a rotor disposed inside the stator and facing the plurality of teeth;
A rotating electrical machine comprising
The rotor has a rotor core that holds permanent magnets with 16 to 32 poles, and a rotating shaft that rotates integrally with the rotor core,
Each of the plurality of teeth includes a rod portion protruding radially inwardly of the yoke portion from an inner peripheral edge of the yoke portion, and a rod portion closer to the rotor than the rod portion and wider than the rod portion. and a flared portion that is interposed between the neck portion and the collar portion and that widens from the neck portion toward the collar portion,
The crossing angle between the rod portion and the expanding portion is 108° to 130°,
A rotary electric machine is provided in which the distance from the inner peripheral end of the collar portion to the outer peripheral end thereof is 0.2 mm to 2.0 mm.

In the present invention, in the tooth portion of the stator, the intersection angle of the expanded portion with respect to the rod portion is set within a predetermined range. Also, in the tooth portion, the thickness of the collar portion is set within a predetermined range. When the shape of the tooth portion is defined in this way, the collar portion can sufficiently receive the magnetic flux of the permanent magnet. Therefore, even if the number of poles is as large as 16 to 32, the stator can sufficiently receive the magnetic flux of the permanent magnets. Therefore, for example, a sufficiently large rotational torque can be obtained even when the rotating shaft rotates at a low speed.

Moreover, since the stator sufficiently receives the magnetic flux of the permanent magnet, leakage magnetic flux is reduced. As a result, the magnetic flux linkage and eddy currents in the electromagnetic coil are reduced. For the above reasons, the heat generation of the stator (especially the electromagnetic coil) can be suppressed.

FIG. 1 is a schematic horizontal cross-sectional view of a main part of a rotating electric machine according to an embodiment of the present invention. 2 is an enlarged view of a main part of FIG. 1. FIG. FIG. 3 is an overall schematic plan view of the rotor core. FIG. 4 is an overall schematic plan view of one electromagnetic steel sheet forming the rotor core. FIG. 5 is an exploded perspective view of the main parts of the rotor core. FIG. 6 is an exploded perspective view of essential parts of another rotor core. 7 is an enlarged view of a main part of FIG. 1. FIG. FIG. 8 is a schematic horizontal cross-sectional view of main parts of a rotating electric machine according to another embodiment of the present invention. 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.

FIG. 1 is a schematic horizontal cross-sectional view of a main part of a rotary electric machine 10 according to this embodiment. The rotating electric machine 10 includes a substantially annular stator 12 and a rotor 14 arranged inside the stator 12 . The rotating electrical machine 10 is, for example, a three-phase motor having U-phase, V-phase, and W-phase.

First, the stator 12 will be explained. Stator 12 has a stator core 20 . The stator core 20 is, for example, a laminate in which magnetic bodies such as electromagnetic steel sheets are laminated.

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 peripheral edge of the yoke portion 24) is within the range of 230 mm to 450 mm. This outer diameter is smaller than the outer diameter of a general motor that rotates the propeller of a flying object. That is, the rotating electric machine 10 is small.

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

Slots 28 are formed between adjacent tooth portions 26 . If the rotating electrical 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 portions 26 and slots 28 are both 96 pieces. The number of poles (described later) is 16 poles. Therefore, the rotating electric machine 10 is configured as a so-called 16-pole, 96-slot structure. 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 .

2 is an enlarged view of a main part of FIG. 1. FIG. One tooth portion 26 has a neck portion 32 , a flange portion 34 and a flared portion 36 . The rod portion 32 radially extends along the radial direction of the stator core 20 . The flange portion 34 is provided at the tip of the inner circumference of the tooth portion 26 . The expanding portion 36 is interposed between the rod portion 32 and the collar portion 34 .

The rod portion 32 has a first parallel side 40a and a second parallel side 40b. The separation distance W1 between the first parallel side 40a and the second parallel side 40b can be rephrased as the width dimension of the rod portion 32. As shown in FIG. The width direction is substantially orthogonal to the radial direction of stator core 20 .

The expanded portion 36 gradually widens from the neck portion 32 toward the collar portion 34 . In other words, the flared portion 36 tapers toward the rod portion 32 . The expanded portion 36 has a first inclined side 42a and a second inclined side 42b. The first inclined side 42a intersects the first parallel side 40a of the rod portion 32 at an intersection angle θ1. Similarly, the second inclined side 42b intersects the second parallel side 40b at an intersection angle θ2. In this embodiment, the intersection angle θ1 and the intersection angle θ2 are within the range of 108° to 130°. More preferably, the crossing angle θ1 and crossing angle θ2 are within the range of 120° to 125°. By setting the intersection angle θ1 and the intersection angle θ2 within such ranges, the total of copper loss and iron loss in the stator 12 is reduced. The intersection angle θ1 and the intersection angle θ2 are preferably the same. However, the intersection angle θ1 and the intersection angle θ2 may be different.

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. A straight line drawn from the intersection point P1 toward the intersection point P2 is defined as a first imaginary straight line LN1. A 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 expanding portion 36. As shown in FIG.

A first radial side 44a of the flange portion 34 continues to the first inclined side 42a. A second radial side 44b of the flange portion 34 continues to the second inclined side 42b. 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 W2. The separation distance W2 is the width of the collar portion 34 . The width W2 of the collar portion 34 is greater than the width W1 of the neck portion 32 .

Let G be the interval between adjacent flanges 34 . Let DM be the diameter of the wire forming the electromagnetic coil 30 . The width W2 is, for example, the range in which the spacing G is larger than the diameter DM. In this case, magnetic flux saturation at the collar portion 34 is reduced. As a result, the rod portion 32 can receive a large amount of magnetic flux. Therefore, it is possible to improve the rotational torque of the rotating shaft 50 . Further, it is possible to select a magnetic material having a low saturation magnetic flux density as the material (such as an electromagnetic steel sheet) of the stator core 20 . Therefore, cost reduction can be achieved.

The intersection of 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 of 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). A straight line drawn from the intersection point P3 to the intersection point P4 is assumed to be a second virtual straight line LN2. A second imaginary straight line LN2 represents the inner peripheral end of the expanded portion 36 and the outer peripheral end of the collar portion 34 .

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 collar portion 34 . The distance between the third imaginary straight line LN3 and the second imaginary straight line LN2 is assumed to be T1. The separation distance T1 represents the distance from the inner peripheral end of the collar portion 34 to the outer peripheral end of the collar portion 34 . The separation distance T1 is hereinafter defined as the thickness of the flange portion 34 .

A preferable range of the thickness T1 of the collar portion 34 is 0.2 mm to 2.0 mm. A more preferable range for the thickness T1 is 0.3 mm to 1.1 mm. When the thickness T1 is set within such a range, the total of copper loss and iron loss in the stator 12 is reduced.

The outer peripheral end of the rod portion 32 is a portion 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 collar portion 34 is defined as the total length LO of the tooth portion 26 (see FIG. 2). Typically, the total length LO is in the range 40mm-45mm. Further, in a typical example, when the total length LO is 100%, the total length of the neck portion 32 is 96% or more. In this case, the distance from the inner peripheral end of the collar portion 34 to the inner peripheral end of the rod portion 32 is 4% or less of the total length LO of the teeth portion 26 .

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 the wire around the tooth portion 26 . Distributed winding is performed in this embodiment. FIG. 1 illustrates a so-called two-turn case.

As shown in FIG. 2 , the inner peripheral end of the electromagnetic coil 30 is positioned within the slot 28 in a cross section perpendicular to the axial direction of the rotating shaft 50 . The inner peripheral end of the electromagnetic coil 30 is positioned between the inner peripheral end of the collar 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 expanded portion 36 (the inner peripheral end of the rod portion 32 ) and the outer peripheral end of the rod portion 32 . A distance from the inner peripheral end of the collar portion 34 to the inner peripheral end of the electromagnetic coil 30 is defined as an offset amount OF. A preferable range of the offset amount 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 amount OF is 2 mm to 4.4 mm. A more preferable range of the offset amount OF is 5.6% to 10.3% of the total length LO of the tooth portion 26. FIG.

If the offset amount OF is less than 5% of the total length LO of the tooth portion 26, the winding amount of the electromagnetic coil 30 increases. Therefore, the volume of the electromagnetic coil 30 is increased. As a result, the amount of magnetic flux received from the permanent magnets 54 of the rotor 14 increases. Therefore, there is concern that the amount of heat generated by the electromagnetic coil 30 will increase. Also, the copper loss increases. When the offset amount OF exceeds 11%, the copper loss becomes small. However, since the exposed area of the rod portion 32 increases, iron loss increases. As a result, the calorific value increases. Also, since the amount of winding of the electromagnetic coil 30 is reduced, the volume of the electromagnetic coil 30 is reduced. Therefore, the output of the rotating electric machine 10 as a motor is reduced.

When the total length LO of the tooth 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 .

The rotor 14 will be explained. As shown in FIG. 1 , the rotor 14 is arranged inside the teeth 26 .

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

As shown in FIG. 3, the rotor core 52 has a plurality of electromagnetic steel plates 60. As shown in FIG. The rotor core 52 is formed by laminating a plurality of electromagnetic steel sheets 60 . That is, the rotor core 52 is a laminate of a plurality of electromagnetic steel plates 60 .

As shown in FIG. 4, one electromagnetic steel sheet 60 is a thin annular body. The electromagnetic steel sheet 60 has an inner ring portion 62 positioned on the inner circumference and an outer ring portion 64 positioned 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 (10 in the example of FIG. 4) connecting portions 66 . Thus, the connecting portion 66 connects the outer peripheral edge of the inner annular portion 62 and the inner peripheral edge of the outer annular portion 64 .

A circular first insertion hole 70 is formed in the inner annular portion 62 . The rotary shaft 50 shown in FIG. 1 is passed through the first insertion hole 70 . A center O of the rotating shaft 50 coincides with the center of the first insertion hole 70 .

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

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 the range of 1:1.5 to 1:3.5. In this case, Rin:Rout=1:1.5-3.5.

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 . One second insertion hole 74 is rectangular. The two second insertion holes 74 are close to each other and form a set. A set of second insertion holes 74 (two second insertion holes 74 adjacent to each other) is hereinafter referred to as a "hole group 76". The distance between adjacent hole groups 76 is greater than the distance between second insertion holes 74 in one hole group 76 . A separation angle (phase difference) α between adjacent hole groups 76 is 22.5° in this case.

A permanent magnet 54 is inserted into the second insertion hole 74 . Since the number of second insertion holes 74 is 32, the number of permanent magnets 54 is also 32. As shown in FIG. Two permanent magnets 54 are inserted into one set of hole groups 76 such that the same magnetic poles face the outer periphery. In FIG. 3, the north pole of the permanent magnet 54 is shown with a mesh. On the other hand, the south pole is not meshed. The same applies to subsequent drawings.

As can be seen from FIG. 3, in any one set of holes 76, the north poles of the two permanent magnets 54 face the outer circumference. 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 circumference. In the following description, simply referring to "N pole" or "S pole" indicates a magnetic pole facing the outer circumference. In stator 12, two south poles are interposed between two north poles and another two north poles.

Hereinafter, the same magnetic pole facing the outer periphery of the two permanent magnets 54 housed in one set of hole groups 76 is counted as one pole. That is, two adjacent N poles in one set of hole groups 76 are one pole. Similarly, two adjacent south poles in another set of hole groups 76 are also single poles. In this embodiment, 16 groups of holes 76 are formed. Therefore, the number of magnetic poles is 16 pieces. Thus, the rotary electric machine 10 is a 16-pole, three-phase motor. In this specification, the number of magnetic poles obtained in this manner is defined as "the number of poles".

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 a direction that is inclined with respect to the diameter of the electromagnetic steel plate 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°.

However, the number of connecting portions 66 is not limited to ten. Therefore, the intersection angle β is not limited to 36° either. A preferable number of connecting portions 66 is 10 to 30. A preferred range for the crossing angle β is 12° to 36°. When the intersection angle β is within such a range, the connecting portion 66 exhibits sufficient rigidity. Therefore, the connecting portion 66 is prevented from bending under the total weight of the outer annular portion 64 and the permanent magnets 54 .

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 set the number of connecting portions 66 to 30. In this case, the crossing angle β between adjacent connecting portions 66 is 12°. When the number of poles is 24, it is preferable to set the number of connecting portions 66 to 18. In this case, the crossing angle β between adjacent connecting portions 66 is 20°.

FIG. 5 is an exploded perspective view of the main parts of the rotor core 52. As shown in FIG. In FIG. 5, four electromagnetic steel sheets 60 are shown. To facilitate understanding, the lowermost magnetic steel sheet 60 in FIG. 5 is referred to as the first magnetic steel sheet 601. The hole group 76 of the first electromagnetic steel sheet 601 is referred to as the first hole group 761 , and the connecting portion 66 of the first electromagnetic steel plate 601 is referred to as the first connecting portion 661 . The electromagnetic steel sheet 60 laminated 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 plate 602 is referred to as a second connecting portion 662 . The electromagnetic steel sheet 60 laminated 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 the third hole group 763 , and the connecting portion 66 of the third electromagnetic steel plate 603 is referred to as the third connecting portion 663 . The electromagnetic steel sheet 60 laminated 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 the fourth hole group 764 , and the connecting portion 66 of the fourth electromagnetic steel plate 604 is referred to as the fourth connecting portion 664 .

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

The third electromagnetic steel sheet 603 is laminated on the second electromagnetic steel sheet 602 while being rotated by 45 degrees with respect to the second electromagnetic steel sheet 602 and rotated by 90 degrees with respect to the first electromagnetic steel sheet 601 . In this case, a phase difference of 9° is generated between the second connecting portion 662 and the third connecting portion 663 and a phase difference of 18° is generated between the first connecting portion 661 and the third connecting portion 663 . A third hole group 763 continues to the first hole group 761 and the second hole group 762 .

The fourth electromagnetic steel sheet 604 is rotated by 45 degrees with respect to the third electromagnetic steel sheet 603, rotated by 90 degrees with respect to the second electromagnetic steel sheet 602, and rotated by 135 degrees with respect to the first electromagnetic steel sheet 601. It is laminated on the third electromagnetic steel plate 603 . 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° is generated between the first connecting portion 661 and the fourth connecting portion 664 . A fourth hole group 764 is connected to the first hole group 761 , the second hole group 762 and the third hole group 763 .

A combination of the first to fourth electromagnetic steel plates 601 to 604 is defined as one set of plate group 80 . Another set of plate groups 80 is stacked on one set of plate groups 80 . Therefore, the first electromagnetic steel sheet 601 in another set of plate group 80 is laminated directly above the fourth electromagnetic steel sheet 604 in one set of plate group 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 connecting portion 661 in the first electromagnetic steel plate 601 in the plate group 80 below are the first positions in the plate group 80 above. It corresponds to the position of the first hole group 761 and the first connecting portion 661 in the electromagnetic steel sheet 601 (overlaps each other).

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 continuous. The permanent magnets 54 pass through all the hole groups 76 along the stacking direction of the electromagnetic steel plates 60 . In addition, the inner ring portions 62 of the first to fourth electromagnetic steel plates 601 to 604 all overlap.

On the other hand, 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 the 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 holes 72 between the adjacent first connecting portions 661 are not blocked by the second connecting portion 662, the third connecting portion 663 and the fourth connecting portion 664. FIG.

Therefore, in the rotor core 52 , the through holes 72 partially overlap each other along the stacking direction of the electromagnetic steel plates 60 . Based on the series of through holes 72 in this way, flow paths 82 (through holes 72) are formed in the rotor core 52 along the stacking direction of the electromagnetic steel sheets 60, as shown in FIG.

As shown in FIG. 6, a group of plate groups 81 may be provided by stacking a plurality of electromagnetic steel plates 60 in phases in which all the connecting portions 66 overlap each other. In this case, when another plate group 81 is stacked directly above the plate group 81, the connecting portion 66 of the lower plate group 81 and the connecting portion 66 of the upper plate group 81 are in phases that do not overlap. For example, a phase difference of 9° is provided between the connecting portion 66 of the lower plate group 81 and the connecting portion 66 of the upper plate group 81 . The plate group 81 to be laminated next is also set to a phase (a phase difference of 9°) in which the connecting portion 66 of the plate group 81 does not overlap the connecting portion 66 of the two plate groups 81 already laminated. The plate group 81 to be laminated next is also set to a phase (a phase difference of 9°) in which the connection portions 66 of the plate group 81 do not overlap the connection portions 66 of the three plate groups 81 already laminated. The above lamination may be repeated. In either case, when the rotor 14 is viewed in the axial direction of the rotor 14, the shape shown in FIG. 3 is obtained. That is, the rotor core 52 is obtained.

The two permanent magnets 54 located in one set of holes 76 are either north poles or south poles as described above. That is, the number of poles of the permanent magnet 54 in one set of hole groups 76 is one. The two permanent magnets 54 face the rod portion 32 via the collar portion 34 . In this embodiment, the number of poles is 16 and the number of tooth portions 26 is 96. As shown in FIG. Therefore, the average number of tooth portions 26 for one magnetic pole (in this embodiment, two permanent magnets 54 provided in one set of hole groups 76) is six.

Since the number of tooth portions 26 is 96, the number of slots 28 is also 96. As shown in FIG. Therefore, the average number of slots 28 for one magnetic pole is also six (see FIG. 7). Thus, the average number of teeth 26 or slots 28 for one magnetic pole can be calculated.

7 shows the moment when one N pole (two permanent magnets 54 provided in one set of hole groups 76) faces six slots 28. FIG. In this case, about half of the tooth portion 26 faces the lower S pole, and about half of another tooth portion 26 faces the upper S pole. In addition, all five teeth 26 face two S poles. Therefore, even in this case, the average number of tooth portions 26 facing two S poles is six.

It should be noted that when the rotor 14 rotates slightly from FIG. 7, the six teeth 26 as a whole face each other between the two permanent magnets 54 provided in one set of hole groups 76 . Also, about half of the slots 28 face the lower south pole, and about half of the slots 28 face the upper south pole. In addition, all five slots 28 face two south poles. Therefore, even in this case, the average number of slots 28 facing two south poles is six.

The rotor 14 has a rotating shaft 50 . The rotary shaft 50 is rotatably supported by a support member (not shown). The rotating shaft 50 is provided with bearings (not shown). The bearing is interposed between the rotating shaft 50 and the support member.

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 rotor rotates as the electromagnetic coil 30 is energized and the rotating shaft 50 rotates. The rotating body is, for example, a propeller or the like.

The rotary electric machine 10 according to this embodiment is basically configured as described above. Next, the effects of this rotating electric machine 10 will be described.

As described above, the rotor core 52 is formed by stacking a plurality of electromagnetic steel sheets 60 . A through hole 72 is formed in each electromagnetic steel sheet 60 . Therefore, each electromagnetic steel sheet 60 is lightweight. Therefore, the rotor core 52 becomes lightweight. Therefore, the rotating electric machine 10 also becomes lightweight.

Further, as described above, in the present embodiment, the maximum outer diameter of the rotating electric machine 10 is 450 mm. That is, the rotating electric machine 10 is relatively small. Thus, according to the present embodiment, it is possible to reduce the size and weight of the rotary electric machine 10 .

The rotary electric machine 10 is used, for example, as a rotational drive source for a propeller of a flying object. In this case, rotating electric machine 10 is used as a three-phase motor.

In order to drive the rotary electric machine 10 as a three-phase motor, the electromagnetic coils 30 are energized. The electromagnetic coil 30 forms an alternating magnetic field as it is energized. The alternating magnetic field repels or attracts the magnetic field of permanent magnet 54 . Accordingly, the rotating shaft 50 and the rotor core 52 rotate integrally. Therefore, the permanent magnets 54 move in a circle along the outer edge of the rotor core 52 .

In order to obtain high torque when the rotational speed of the rotating shaft 50 is low, it is necessary to use a bearing with a large diameter. The inner diameter of the rotor is sized to support a large diameter bearing. Here, if the ratio of the rotor inner diameter to the rotor outer diameter is within the range of 1:1.5 to 1:3.5, the diameter of the electromagnetic steel plate 60 (the diameter of the rotor 14) is suppressed from increasing. . Therefore, in this case, the rotor 14 can support bearings with a large diameter while being compact.

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

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 in one set of hole groups 76) is six. Thus, in this embodiment, the number of slots 28 facing one magnetic pole is appropriately determined. As a result, the rotational torque of the rotary shaft 50 is increased even though the diameter of the rotary electric machine 10 is relatively small. That is, the rotary electric machine 10 can impart a large rotational driving force to a rotating body such as a propeller, although it is a small and lightweight three-phase motor.

Moreover, in this case, leakage magnetic flux is reduced. As a result, the interlinking magnetic flux of the electromagnetic coil 30 is reduced. Therefore, the eddy current of the electromagnetic coil 30 is reduced, and the heat generation of the electromagnetic coil 30 is suppressed.

Further, in the tooth portion 26, the crossing angles θ1 and θ2 between the rod portion 32 and the widening portion 36 are within the range of 108° to 130°. A 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 tooth portion 26 is within the range of 5 to 11%. By setting the intersection angle θ, the thickness T1, and the offset amount OF within such ranges, the total iron loss and copper loss in the stator 12 can be reduced. Therefore, heat generation of the stator 12 is suppressed.

Also, by appropriately setting the offset amount OF, the leakage magnetic flux is reduced. As a result, for example, the teeth 26, the electromagnetic coil 30, or the like can be prevented from locally increasing in temperature. Therefore, deterioration of the material of the stator core 20 (such as the electromagnetic steel sheet 60) or the material of the electromagnetic coil 30 (such as copper) due to this temperature rise is suppressed.

As described above, according to the present embodiment, it is possible to improve the rotational torque of the rotating shaft 50 while reducing the size and weight of the rotary electric machine 10 . Therefore, when the rotary 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.

A cooling medium (for example, cooling air) is supplied to the rotating electric machine 10 . A portion of the cooling medium passes between stator core 20 and rotor core 52 . Another part of the cooling medium passes through flow passages 82 (through holes 72 ) formed in rotor core 52 . As described above, the rotating electric machine 10 is cooled.

In the rotor core 52, a phase difference is provided between one electromagnetic steel sheet 60 and the electromagnetic steel sheets 60 stacked directly above. Therefore, in the two laminated electromagnetic steel sheets 60, a phase difference is generated between the through holes 72 as well. Therefore, in the rotor core 52, the cooling medium is prevented from concentrating or remaining in one flow passage 82. FIG. In other words, the cooling medium is substantially evenly distributed to the plurality of circulation holes, and then the distributed cooling medium easily flows through the individual circulation holes. Therefore, the entire rotary electric machine 10 is efficiently and substantially evenly cooled.

Stress acts on the rotor core 52 while the rotor core 52 is rotating. Here, in the two laminated electromagnetic steel sheets 60, a phase difference is also generated between the connecting portions 66. As shown in FIG. Therefore, the stress is dispersed between the connecting portions 66 having a phase difference. Therefore, concentration of stress on any connecting portion 66 is avoided. For this reason, the durability of the connecting portion 66 is improved.

As described above, in this embodiment, the yoke portion (24) having an annular shape and a plurality of teeth portions (26) protruding radially inwardly of the yoke portion from the inner peripheral edge of the yoke portion. a stator (12) having a slot (28) formed between adjacent tooth portions among the plurality of tooth portions;
a rotor (14) disposed inside the stator and facing the plurality of teeth;
A rotating electric machine (10) comprising:
The rotor has a rotor core (52) holding a permanent magnet (54) having 16 to 32 poles, and a rotating shaft (50) that rotates integrally with the rotor core,
Each of the plurality of teeth includes a rod portion (32) protruding radially inwardly of the yoke portion from the inner peripheral edge of the yoke portion, and a rod portion closer to the rotor than the rod portion and close to the rod portion. and a widened portion (36) that is interposed between the neck portion and the collar portion and that widens from the neck portion toward the collar portion,
crossing angles (θ1, θ2) between the rod portion and the expanding portion are 108° to 130°;
A rotating electrical machine is disclosed in which the distance from the inner peripheral end of the collar portion to the outer peripheral end thereof is 0.2 mm to 2.0 mm.

As described above, in the present embodiment, in the tooth portion of the stator, the intersection angle of the expanded portion with respect to the rod portion is set within a predetermined range. Also, in the tooth portion, the thickness of the collar portion is set within a predetermined range. By defining the shape of the tooth portion in this manner, the collar portion can sufficiently receive the magnetic flux of the permanent magnet. Therefore, even when the number of poles is large (the number of permanent magnets is large), leakage magnetic flux is reduced. As a result, the magnetic flux linkage and eddy currents in the electromagnetic coil are reduced. For the above reasons, the heat generation of the stator (especially the electromagnetic coil) can be suppressed.

Moreover, even when the number of poles is large, the flange can sufficiently receive the magnetic flux of the permanent magnet, so the number of poles can be increased to 16 to 32 poles. Thereby, for example, even when the rotating shaft rotates at a low speed, a sufficiently large rotating torque can be obtained.

This embodiment discloses a rotary electric machine in which the average number of slots per magnetic pole is six when the stator and the rotor are viewed in the axial direction of the stator.

In this case, the average number of slots and teeth facing one magnetic pole is determined appropriately. As a result, even if the diameter of the rotating electrical machine is relatively small, the rotating torque of the rotating shaft is increased. Therefore, when the rotating electrical 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 in spite of its small size and light weight. That is, the rotating electric machine can continuously output high torque.

Moreover, in this case, leakage magnetic flux is reduced. As a result, the magnetic flux linkage of the electromagnetic coil is reduced. Therefore, eddy currents in the electromagnetic coil are reduced, and heat generation of the electromagnetic coil is suppressed.

In addition, the number of poles and the number of slots are defined as above. In this case, a large rotational torque can be obtained in the rotating shaft while avoiding an excessive increase in the diameter of the rotating electric machine. Therefore, it is possible to obtain a small-sized motor with high output.

In this embodiment, the rotor core includes a first insertion hole (70) in which the rotating shaft is arranged, a plurality of through holes (72) formed radially outside the first insertion hole, and the plurality of through holes (72). a plurality of second insertion holes (74) formed radially outward of the through holes and into which the permanent magnets are inserted;
The rotor core includes an inner annular portion (62) positioned between the plurality of through holes and the first insertion hole, and a plurality of rotor cores positioned radially outwardly of the plurality of through holes. Disclosed is a rotating electric machine having an outer ring portion (64) formed with a second insertion hole and a plurality of connecting portions (66) connecting the inner ring portion and the outer ring portion.

A through hole is provided between the adjacent connecting portions. That is, the rotor core is formed with a plurality of through holes. The rotor core is lightweight due to the through holes. Therefore, the weight of the rotary electric machine can be reduced.

In this embodiment, the rotor core is a laminate of a plurality of electromagnetic steel sheets (60), and each of the plurality of electromagnetic steel sheets has the first insertion hole, the plurality of through holes and the plurality of through holes. A rotating electric machine is disclosed in which a second insertion hole is formed, and each of the plurality of electromagnetic steel plates has the inner annular portion, the outer annular portion, and the connecting portion.

In order to obtain a single-member rotor core having a large thickness, for example, it is necessary to form a first insertion hole, a through hole, and a second insertion hole by punching a cylindrical workpiece. However, it is not easy to perforate a thick work. On the other hand, when the rotor core is obtained by laminating the magnetic steel sheets having the above-described shape, the first insertion hole, the through hole, and the second insertion hole are formed only by laminating the magnetic steel sheets.

Individual electromagnetic steel sheets are obtained, for example, by punching a thin disk-shaped workpiece and forming a first insertion hole, a through hole, and a second insertion hole. Punching a thin disk-shaped work can be performed more easily than punching a thick work. Therefore, it is possible to easily manufacture the rotor core.

This embodiment discloses a rotating electrical machine in which the plurality of magnetic steel sheets are laminated in the first mode or the second mode.

In a first aspect, the plurality of connecting portions (661) of one of the plurality of electromagnetic steel plates (601) adjacent to each other and the other of the plurality of electromagnetic steel plates adjacent to each other ( 602) are laminated so that they do not overlap when the rotor is viewed in the axial direction of the rotor.

In a second aspect, a plurality of plate groups (81) each having the plurality of electromagnetic steel sheets are laminated in the axial direction, and the plurality of the plurality of plate groups in one of the plurality of plate groups adjacent to each other The connecting portion (661) and the plurality of connecting portions (662) of the other plate group adjacent to each other in the plurality of plate groups are positioned so as not to overlap each other when the rotor is viewed in the axial direction. It is a mode in which it is laminated on.

Since the connecting portions of two (or two groups of) electromagnetic steel plates stacked vertically do not overlap each other, concentration of stress on a connecting portion of an arbitrary phase can be avoided. That is, the stress is appropriately distributed for each of the coupling portions that are out of phase. As a result, the durability of the connecting portion is improved.

This embodiment discloses a rotating electric machine in which the outer diameter of the stator is within the range of 230-450 mm. 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".

A rotating electrical machine with such an outer diameter is relatively small. That is, the rotary electric machine can continuously output high torque while being small.

It should be noted that the present invention is not limited to the above-described embodiments, and can take various configurations without departing from the gist of the present invention.

In the above-described embodiment, the rotary electric machine 10 with 16 poles and 96 slots is exemplified. However, the number of poles or slots 28 is not particularly limited. For example, as shown in FIG. 8, a rotating electrical machine 90 with 24 poles and 144 slots may be used. Alternatively, as shown in FIG. 9, a rotating electrical machine 100 with 32 poles and 192 slots may be used. In both cases, the number of slots 28 per pole is six. 8 and 9, the electromagnetic coil 30 is omitted.

As the number of poles and the number of slots 28 increase, the distance X from the center of rotation of the rotor 14 (the center O of the rotating shaft 50) to the outer peripheral edge of the stator core 20 tends to increase. Since twice the distance X is the outer diameter of the rotary electric machine 10, the outer diameter is increased in this case. However, by setting the dimensions of each part, the intersection angle, etc., to the same numerical range as that of the rotating electrical machine 10 illustrated in FIG. Therefore, the rotating electrical machines 90 and 100 can also be reduced in size and weight.

Moreover, the rotational torque of the rotary shaft 50 can be improved by setting the dimensions of each part, the crossing angle, etc. within the same numerical range as the rotary electric machine 10 illustrated in FIG. Therefore, according to the rotary electric machines 90 and 100, it is possible to continuously output high torque. That is, in rotating electric machines 90 and 100, the same effects as those of rotating electric machine 10 can be obtained.

Instead of winding a wire around the tooth portion 26, the metal conductor shown in FIG. 1 of Japanese Patent Application Laid-Open No. 2020-39207 may be used. This metal conductor has two legs. By inserting a predetermined number of metal conductor legs into slots 28, an electromagnetic coil is formed.

The rotary electric machine 10, 90, 100 may function as a generator. In this case, an alternating current is applied to the electromagnetic coil 30 from an external power source.

DESCRIPTION OF SYMBOLS 10, 90, 100... Rotary electric machine 12... Stator 14... Rotor 20... Stator core 24... Yoke part 26... Teeth part 28... Slot 30... Electromagnetic coil 32... Neck part 34... Flange part 36... Expansion part 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 magnets 60, 601 to 604 Electromagnetic steel plate 62 Inner annular portion 64 Outer annular portion 66, 661 to 664 Connecting portion 70 First insertion hole 72 Through hole 74 Second insertion hole 76, 761 to 764 Hole group 80, 81 Plate group 82... Distribution path LN1... First imaginary straight line LN2... Second imaginary straight line LN3... Third imaginary straight line LO... Total length of tooth portion OF... Offset amount α... Phase difference β, θ1, θ2... Crossing angle

Claims (6)

A yoke portion having an annular shape and a plurality of tooth portions protruding radially inwardly of the yoke portion from an inner peripheral edge of the yoke portion, wherein the plurality of tooth portions are adjacent to each other. a stator with a slot formed therebetween;
a rotor disposed inside the stator and facing the plurality of teeth;
A rotating electrical machine comprising
The rotor has a rotor core that holds permanent magnets with 16 to 32 poles, and a rotating shaft that rotates integrally with the rotor core,
Each of the plurality of teeth includes a rod portion protruding radially inwardly of the yoke portion from an inner peripheral edge of the yoke portion, and a rod portion closer to the rotor than the rod portion and wider than the rod portion. and a flared portion that is interposed between the neck portion and the collar portion and that widens from the neck portion toward the collar portion,
The crossing angle between the rod portion and the expanding portion is 108° to 130°,
The rotary electric machine, wherein the distance from the inner peripheral end of the collar portion to the outer peripheral end thereof is 0.2 mm to 2.0 mm. 2. The electric rotating machine according to claim 1, wherein the 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. The rotary electric machine according to claim 1, wherein the rotor core includes a first insertion hole in which the rotating shaft is arranged, a plurality of through holes formed radially outward of the first insertion hole, and the plurality of a plurality of second insertion holes formed radially outside the through holes and into which the permanent magnets are inserted;
The rotor core includes an inner annular portion positioned between the plurality of through holes and the first insertion hole, and a plurality of second insertion holes positioned radially outside the plurality of through holes. A rotating electric machine, comprising: an outer annular portion formed with a hole; and a plurality of connecting portions that connect the inner annular portion and the outer annular portion. 4. The rotary electric machine according to claim 3, wherein the rotor core is a laminate of a plurality of electromagnetic steel sheets, and each of the plurality of electromagnetic steel sheets has the first insertion hole, the plurality of through holes and the plurality of through holes. second insertion holes are formed, and each of the plurality of electromagnetic steel plates has the inner annular portion, the outer annular portion, and the connecting portion. 5. The rotating electric machine according to claim 4, wherein the plurality of electromagnetic steel sheets are laminated in a first mode or a second mode,
In the first aspect, the plurality of connecting portions of one of the plurality of electromagnetic steel sheets adjacent to each other and the plurality of connecting portions of the other of the plurality of electromagnetic steel sheets adjacent to each other. and are laminated so that they do not overlap when the rotor is viewed in the axial direction of the rotor,
In the second aspect, a plurality of plate groups each having the plurality of electromagnetic steel sheets are laminated in the axial direction, and the plurality of connecting portions of one of the plate groups 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 so that they do not overlap when the rotor is viewed in the axial direction. electric machine. The rotating electric machine according to any one of claims 1 to 5, wherein said stator has an outer diameter within a range of 230 to 450 mm.

Images