JP6765983B2 - Rotating electric machine - Google Patents

Description

The present application discloses a rotary electric machine including a stator, an annular outer rotor arranged around the outer periphery of the stator, and an annular outer rotor.

Conventionally, a permanent magnet type rotary electric machine using a permanent magnet as a magnetic pole of a rotor has been widely known. Generally, in a permanent magnet type rotary electric machine, in order to obtain high torque, it is necessary to increase the amount of magnetic flux (magnet magnetic flux) of the permanent magnet flowing through the stator. On the other hand, when the current flowing through the stator coil is zero or small, when there is no load or when the load is low, if the amount of magnet magnetic flux flowing through the stator is large, there causes a problem that the counter electromotive voltage and iron loss increase. The counter electromotive voltage can be suppressed by performing field weakening control, but when field weakening control is performed, it is necessary to separately pass a negative d-axis current that is for weakening field and does not contribute to output, resulting in an increase in copper loss. Was invited.

Patent Document 1 discloses a variable magnetic flux type rotary electric machine in which the amount of magnetic flux (interlinkage magnetic flux) flowing through the stator is variable. The rotary electric machine of Patent Document 1 is an inner rotor type in which a rotor is arranged inside a stator, and the rotor has a permanent magnet magnetized in the radial direction. An electrical gap is formed between two adjacent permanent magnets in the rotor core. A magnetic flux bypass path is formed between the gap and the outer peripheral edge of the rotor core by the two adjacent permanent magnets. This magnetic flux bypass path is wider and has less magnetoresistance than the magnetic path formed between the gap and the permanent magnet. Therefore, when the current is not applied, a part of the magnetic flux generated from the permanent magnet leaks to the adjacent permanent magnet through the magnetic flux bypass path. This leakage of magnet magnetic flux is suppressed by armature reaction when the stator coil is energized. As a result, when rotating under no load or low load, the amount of magnet magnetic flux flowing through the stator can be reduced, and the counter electromotive voltage and iron loss can be reduced. Further, when rotating under a high load, the magnetic flux leaking to the magnetic flux bypass decreases and the interlinkage magnetic flux increases, so that a high torque can be obtained.

Special Table 2015-521838

Here, among the rotary electric machines, as in Patent Document 1, in addition to the inner rotor type rotary electric machine in which the rotor is arranged inside the stator, the outer rotor type rotary electric machine in which the rotor is arranged outside the stator There is also. In the case of the outer rotor type, even if the radial thickness of the rotor is the same as that of the inner rotor type, the centrifugal force generated by the rotation becomes large. Therefore, the outer rotor type is required to have a smaller rotor radial thickness than the inner rotor type.

The technique disclosed in Patent Document 1 requires a magnetic flux bypass having a sufficient width to be provided between the electrical gap and the outer peripheral edge of the rotor. Such a technique is effective for an inner rotor type having a large radial thickness of the rotor. However, as described above, it is difficult to apply the technique of Patent Document 1 to the outer rotor type, which is required to keep the thickness in the radial direction small in relation to the centrifugal force.

Therefore, an object of the present application is to obtain an outer rotor type rotary electric machine capable of obtaining high torque at high load and reducing back electromotive voltage and iron loss at no load or low load.

The rotary electric machine disclosed in the present application is a stator, an annular outer rotor arranged around the outer periphery of the stator, an outer rotor in which a plurality of core pieces and a plurality of outer magnets are alternately arranged in the circumferential direction, and the outer. A short-circuit member arranged on the outer side in the radial direction of the magnet and magnetically short-circuiting two core pieces located on both sides in the circumferential direction of the outer magnet is provided, and the outer magnet is adjacent in the circumferential direction and in the circumferential direction. are magnetized to the other outer magnets circumferentially opposite, said short-circuit member is made of a soft magnetic material maximum permeability is higher than the core pieces, rather small, the saturation magnetization than the core pieces, the outer magnet Is characterized in that the outer peripheral edge thereof is arranged so as to be radially inside the outer peripheral edge of the core piece .

With such a configuration, in a no-load or low-load state where there is no or little current magnetic flux, a part of the magnet magnetic flux is short-circuited via the short-circuit member. As a result, the magnet magnetic flux flowing through the stator is reduced in the no-load / low-load state, and the counter electromotive voltage and iron loss can be reduced. Further, in a high load state where the current magnetic flux increases, the short-circuit member is magnetically saturated by the current magnetic flux, so that the short-circuited magnet magnetic flux decreases and the magnet magnetic flux flowing through the stator increases. As a result, a high torque can be output in a high load state.

Before SL shorting member has its circumferential end surface is disposed in contact or closely facing the circumferential end faces of the two core pieces, the contact with the maximum permeability than the core pieces are made of high soft magnetic material Alternatively, it may include a first member having a smaller saturation magnetization than the closely opposed core pieces.

With such a configuration, the magnetic resistance of the short-circuit magnetic path of the magnet magnetic flux is reduced, and the magnet magnetic flux flowing through the stator can be further reduced in the no-load / low-load state. As a result, the counter electromotive voltage and the iron loss can be further reduced in the no-load / low-load state.

Further, the short-circuit member is made of a soft magnetic material having an inner peripheral surface thereof which is arranged so as to be in contact with or close to the outer peripheral surfaces of the two core pieces and has a higher maximum magnetic permeability than the core piece, and the contact. Alternatively, it may include a second member having a smaller saturation magnetization than the closely opposed core pieces.

In this case, the second member may be a fixing outer cylinder that surrounds and fixes the outer periphery of the outer rotor.

With such a configuration, it is not necessary to provide a second member separately from the fixing outer cylinder, and the number of parts and cost of the rotary electric machine can be reduced.

Further, the short-circuit member and the core piece may face each other in close proximity to each other through a gap.

With such a configuration, the change characteristic of the interlinkage magnetic flux with respect to the load state can be adjusted by adjusting the size of the gap.

According to the rotary electric machine disclosed in the present application, a part of the magnet magnetic flux is short-circuited via the short-circuit member in a no-load or low-load state where there is no or little current magnetic flux. As a result, the magnet magnetic flux flowing through the stator is reduced in the no-load / low-load state, and the counter electromotive voltage and iron loss can be reduced. Further, in a high load state where the current magnetic flux increases, the short-circuit member is magnetically saturated by the current magnetic flux, so that the short-circuited magnet magnetic flux decreases and the magnet magnetic flux flowing through the stator increases. As a result, a high torque can be output in a high load state.

It is a schematic vertical sectional view of a rotary electric machine. It is a schematic cross-sectional view of a rotary electric machine. It is an enlarged view of part A of FIG. It is an image figure which shows the flow of the magnet magnetic flux in a low load state. It is an image figure which shows the flow of the magnet magnetic flux in a high load state. It is a figure which shows the simulation result of the magnet magnetic flux in a no-load state. It is a figure which shows the simulation result of the current magnetic flux in a high load state. It is a figure which shows the simulation result of the magnet magnetic flux in a high load state. It is a figure which shows another example of an outer rotor. It is a figure which shows another example of an outer rotor.

Hereinafter, the rotary electric machine 10 disclosed in the present application will be described with reference to the drawings. In the following, a dual rotor type rotary electric machine having rotors on both the inside and outside of the stator will be described as an example. However, the technique of the present application is an outer rotor having a rotor arranged on the outside of the stator. As long as it is a type, it may be applied to either a dual rotor type or a single rotor type.

FIG. 1 is a schematic vertical sectional view of the rotary electric machine 10. Further, FIG. 2 is a schematic cross-sectional view of the rotary electric machine 10. FIG. 3 is an enlarged view of part A of FIG. The rotary electric machine 10 is a dual rotor type rotary electric machine having one stator 14 and two rotors 16 and 18. More specifically, as shown in FIGS. 1 and 2, an inner rotor 16 is fixed to the outer peripheral surface of the rotating shaft 20, a stator 14 is arranged around the outer circumference of the inner rotor 16, and further, the stator 14 is arranged. The outer rotor 18 is arranged around the outer circumference of the.

The outer rotor 18 is fixed to the rotating shaft 20 via the connecting member 22. The connecting member 22 is a substantially flat plate-shaped member that is inserted and fixed to the rotating shaft 20. Among the connecting members 22, an annular rib 22a extending toward the outer rotor 18 is provided from the surface facing the outer rotor 18. The tip surface of the annular rib 22a is fixed to the axial end surface of the outer rotor 18. Then, the rotating force of the outer rotor 18 is transmitted to the rotating shaft 20 via the connecting member 22. The configuration of the connecting member 22 shown here is an example, and other configurations may be used as long as the rotational forces of the outer rotor 18 and the inner rotor 16 are transmitted to the rotating shaft 20. For example, the connecting member 22 may be fixed to the inner rotor 16 instead of the rotating shaft 20. In this case, the rotational force of the outer rotor 18 is applied to the rotating shaft 20 via the connecting member 22 and the inner rotor 16. Be transmitted. Further, as another form, the inner rotor 16 may not be fixed to the rotating shaft 20, but the inner rotor 16 and the outer rotor 18 may be fixed to the connecting member 22, and the connecting member 22 may be fixed to the rotating shaft 20. .. In any case, in the dual rotor type rotary electric machine 10, the rotational force of the inner rotor 16 and the outer rotor 18 is transmitted to one rotating shaft 20.

The stator 14 has a stator core 26 and a stator coil 28 wound around the stator core 26. As shown in FIG. 2, the stator core 26 includes an annular yoke 29, a plurality of inner teeth 30 projecting radially inward from the inner circumference of the yoke 29, and a plurality of inner teeth 30 projecting radially outward from the outer circumference of the yoke 29. It is roughly divided into the outer teeth 32 of. The space between the two adjacent inner teeth 30 becomes the inner slot 31, and the space between the two adjacent outer teeth 32 becomes the outer slot 33.

The arrangement pitch angle and phase of the inner teeth 30 are the same as the arrangement pitch angles and phases of the outer teeth 32. In the illustrated example, the inner teeth 30 and the outer teeth 32 are both arranged in the circumferential direction at intervals of 15 degrees, and as a whole, 24 inner teeth 30 and 24 outer teeth 32 are provided. That is, the number of slots is 24 both inside and outside. Such a stator core 26 is composed of a plurality of electromagnetic steel sheets (for example, silicon steel sheets). The plurality of electrical steel sheets are positioned and joined to each other to form the stator core 26.

The stator coil 28 is composed of a three-phase coil, that is, a U-phase coil, a V-phase coil, and a W-phase coil. One end of each of the three-phase coils is connected to an input / output terminal (not shown), and the other ends of each of the three-phase coils are coupled to each other to form a neutral point. That is, the stator coil 28 is star-connected. Of course, instead of the star connection, another connection mode, for example, a delta connection or the like may be adopted.

The windings constituting the coils of each phase are wound around the stator core 26. As a winding method, a distributed winding in which the winding is wound so as to straddle a plurality of slots, a centralized winding in which the winding is wound in one tooth, a toroidal winding in which the winding is wound around a yoke 29, etc. It has been known. In this embodiment, the winding is wound with a toroidal winding, that is, the winding is wound around a yoke 29. In this case, when a current is applied to the stator coil 28, the polarity of the magnetic field formed on the outer teeth 32 side and the polarity of the magnetic field formed on the inner teeth 30 side are reversed. However, if necessary, the winding may be wound in a concentrated winding or a distributed winding. In any case, in the following, the magnetic flux generated when a current is applied to the stator coil 28 is referred to as "current magnetic flux".

The inner rotor 16 is a rotor arranged inside the stator 14, and has an annular inner core 34 and an inner magnet 36 embedded in the inner core 34. The inner core 34 is formed by laminating a plurality of electromagnetic steel sheets (for example, silicon steel sheets). The inner magnet 36 is a permanent magnet that constitutes the magnetic pole of the inner rotor 16. The inner magnet 36 has a substantially rectangular shape that is flat in the axial direction, and is magnetized in the short side direction thereof. The shape, number, arrangement position, etc. of the inner magnet 36 are not particularly limited, but as will be described later, the number of magnetic poles of the inner rotor 16 is preferably the same as the number of magnetic poles of the outer rotor 18. In the present embodiment, the inner rotor 16 is provided with eight pole magnetic poles, and one magnetic pole is composed of two inner magnets 36 arranged in a substantially V shape that opens outward in the radial direction. Therefore, the inner rotor 16 as a whole is provided with twice the number of magnetic poles, that is, 16 inner magnets 36. Further, it is desirable that the d-axis Ldi of the inner rotor 16 and the d-axis Ldo of the outer rotor 18 match. Here, the d-axis Ldi of the inner rotor 16 is a straight line connecting the circumferential center of the gap between the two inner magnets 36 constituting one magnetic pole and the center point of the rotary electric machine 10.

The outer rotor 18 is a rotor arranged around the outer periphery of the stator 14, and includes core pieces 38 and outer magnets 40 that are alternately arranged in the circumferential direction. The plurality of core pieces 38 and the outer magnet 40 are arranged alternately to form a substantially annular shape. Each core piece 38 is formed by laminating a plurality of electromagnetic steel sheets (for example, silicon steel sheets).

The outer magnet 40 is a permanent magnet that constitutes the magnetic poles of the outer rotor 18. Since the outer magnet 40 is a permanent magnet, naturally, a constant magnetic flux is always generated from the outer magnet 40. Hereinafter, the magnetic flux generated from the outer magnet 40 is referred to as "magnet magnetic flux", and among the magnet magnetic fluxes, the magnetic flux flowing through the stator 14 and interlinking with the stator coil 28 is referred to as "interlinking magnetic flux".

The outer magnet 40 is substantially rectangular in the axial direction, and one side thereof is arranged so as to be substantially parallel to the circumferential direction. Each outer magnet 40 is magnetized in the substantially circumferential direction. That is, the outer magnet 40 has an N pole at one end in the circumferential direction and an S pole at the other end in the circumferential direction. Further, the magnetization directions of the two outer magnets 40 adjacent to each other in the circumferential direction are opposite to each other in the circumferential direction. That is, the facing surfaces of the two outer magnets 40 adjacent to each other in the circumferential direction are magnetized so as to have the same poles. In this case, one magnetic pole is formed by one side portion in the circumferential direction of each of the two outer magnets 40 adjacent to each other in the circumferential direction. In other words, one outer magnet 40 constitutes a part of one N magnetic pole and a part of one S magnetic pole. The straight line connecting the center of the gap between the two adjacent outer magnets 40 in the circumferential direction and the center point of the rotary electric machine 10 is the d-axis Ldo of the outer rotor 18.

In this example, the number of magnetic poles of the outer rotor 18 is 8 poles, which is the same as the number of magnetic poles of the inner rotor 16. Therefore, eight outer magnets 40 are provided in the entire outer rotor 18. Further, in the present embodiment, the d-axis Ldo of the magnetic pole of the outer rotor 18 and the d-axis Ldi of the magnetic pole of the inner rotor 16 are matched. By matching the two d-axis Ldos and Ldi in this way, the angular relationship between the magnetic poles of the rotors 16 and 18 with respect to the rotating magnetic field of the stator 14 can be made the same on the outer side and the inner side. As a result, it is not necessary to switch the current / voltage control on the outer side and the rotor side. In this embodiment, since the stator coil 28 is toroidally wound, the polarities of the rotating magnetic fields formed on the stator 14 are opposite on the inner side and the outer side. In this case, the magnetic poles of the inner rotor 16 and the magnetic poles of the outer rotor 18 facing each other in the radial direction with the stator 14 interposed therebetween have the same polarity. That is, the N magnetic poles of the inner rotor 16 are arranged on the opposite side of the N magnetic poles of the outer rotor 18 with the stator 14 interposed therebetween, and the inner rotor is arranged on the opposite side of the S magnetic poles of the outer rotor 18 with the stator 14 interposed therebetween. 16 S magnetic poles are arranged.

As described above, the stator coil 28 may be a distributed winding or a concentrated winding in which the winding is wound around the teeth 30 and 32 instead of the toroidal winding in which the winding is wound around the yoke 29. In the case of distributed winding or concentrated winding around the teeth 30 and 32, the winding method is such that the winding directions of the windings are opposite to each other on the outer side and the inner side, and the winding method is the same as each other. , There is. When the winding directions of the windings are outer / inner and opposite to each other, the polarities of the rotating magnetic fields generated by applying the current are opposite to each other in the outer / inner. In this case, it is desirable that the magnetic poles of the inner rotor 16 and the magnetic poles of the outer rotor 18 facing each other in the radial direction with the stator 14 interposed therebetween have the same polarity as in the case of toroidal winding. On the other hand, when the winding directions of the windings are the same for the outer / inner, the polarities of the rotating magnetic fields generated by applying the current are the same for the outer / inner. In this case, it is desirable that the polarities of the magnetic poles of the inner rotor 16 and the magnetic poles of the outer rotor 18 facing each other in the radial direction with the stator 14 interposed therebetween have opposite polarities, contrary to the case of toroidal winding.

The rotary electric machine 10 is further provided with a short-circuit member that magnetically short-circuits two core pieces 38 located on both sides in the circumferential direction with the outer magnet 40 interposed therebetween. There are various possible forms of the short-circuit member, but in this example, the first member arranged on the radial outer side of the outer magnet 40 is used as the short-circuit member.

That is, as is clear from FIG. 3, in this example, the radial thickness of the outer magnet 40 is smaller than the radial thickness of the core piece 38. The outer peripheral edge of the outer magnet 40 is located radially inside the outer peripheral edge of the core piece 38, and the inner peripheral edge of the outer magnet 40 is located radially outside the inner peripheral edge of the core piece 38. From another viewpoint, a concave portion surrounded by the circumferential end surface of the pair of core pieces 38 and the outer peripheral surface of the outer magnet 40 is formed on the outer side in the radial direction of the outer magnet 40. The first member 42 is arranged in this recess.

The circumferential end faces of the first member 42 are in contact with the circumferential end faces of the two core pieces 38, and the first member 42 follows a magnetic path of magnetic flux flowing from one core piece 38 to the other core piece 38. Constitute. The first member 42 is made of a soft magnetic material having a higher maximum magnetic permeability than the core piece 38, and has a smaller saturation magnetization than the two contacting core pieces 38. Therefore, the short-circuit member (first member 42) is more likely to have magnetic flux flowing under a lighter load than the core piece 38, and is more likely to undergo magnetic saturation at a higher load. The short-circuit member (first member 42) is provided in order to make the amount of interlinkage magnetic flux variable according to the load state, which will be described in detail later.

The rotary electric machine 10 of this example further includes a fixing outer cylinder 44 that surrounds and fixes the outer circumference of the core piece 38. The fixing outer cylinder 44 is provided to prevent the core piece 38 and the outer magnet 40 from being separated by surrounding and restraining the core piece 38 and the outer magnet 40. The fixing outer cylinder 44 is made of a non-magnetic material, for example, stainless steel or the like. The fixing outer cylinder 44 may be made of a soft magnetic material, as will be described in detail later. In this case, the fixing outer cylinder 44 is a short-circuit member that magnetically short-circuits the two core pieces 38. Act as part.

Next, in the outer rotor 18, the reason why the outer magnet 40 is magnetized in the circumferential direction and the short-circuit member (first member 42) is arranged on the outer peripheral side of the outer magnet 40 will be described. As a matter of course, since the outer rotor 18 is arranged on the outer side in the radial direction of the stator 14, the distance from the center of rotation is large, and the centrifugal force due to the rotation tends to be large. Therefore, in order to suppress the increase in centrifugal force, the outer rotor 18 is required to suppress the thickness in the radial direction as compared with the inner rotor 16.

Further, a current magnetic flux is generated as the current is applied to the stator coil 28, and a part of the current magnetic flux is radially from the outer teeth 32 to the outer rotor 18 or from the outer rotor 18 to the outer teeth 32. Proceed to. Therefore, when the outer magnet 40 is magnetized in the radial direction, a so-called "reverse magnetic field" is generated in which a current magnetic flux flows in the direction opposite to the direction of magnetization of the outer magnet 40. When such a reverse magnetic field is generated, demagnetization occurs in which the magnetic force of the outer magnet 40 is reduced. Then, the demagnetization of the outer magnet 40 causes a decrease in the magnet torque, which in turn causes a decrease in the output torque of the rotary electric machine 10.

In the rotary electric machine 10 disclosed in the present application, as described above, the outer magnet 40 is magnetized in the circumferential direction. Therefore, it becomes easier to suppress the radial thickness of the outer magnet 40 as compared with the case of magnetizing in the radial direction, and by extension, the radial thickness of the outer rotor 18 can be suppressed. Further, by magnetizing the outer magnet 40 in the circumferential direction, it is possible to suppress a reverse magnetic field in which the current magnetic flux travels in the direction opposite to the magnetization, and it is possible to effectively prevent demagnetization of the outer magnet 40.

By the way, in order to increase the output torque of the rotary electric machine 10, it is necessary to increase the amount of magnet magnetic flux flowing into the stator 14, that is, the amount of interlinkage magnetic flux. On the other hand, if the amount of interlinkage magnetic flux is large, there causes a problem that the counter electromotive voltage and the iron loss become large in a state where the current flowing through the stator coil 28 is zero or small, that is, in a no-load state or a low load state. The counter electromotive voltage can be suppressed by performing field weakening control, but when field weakening control is performed, it is necessary to separately pass a negative d-axis current for weakening field that does not contribute to output, which increases copper loss. Invite.

That is, it is desired that the amount of interlinkage magnetic flux is variable according to the load state so that it is large in the high load state / high torque output state and small in the no-load / low load state. Therefore, in the rotary electric machine 10 disclosed in the present application, a first member 42 that functions as a short-circuit member is provided on the radial outer side of the outer magnet 40 in order to make the amount of interlinkage magnetic flux variable according to the load state. ..

As described above, the first member 42 is made of a soft magnetic material having a higher maximum magnetic permeability than the core piece 38, and has a smaller saturation magnetization than the core piece 38. The flow of the magnetic flux of the magnet when the first member 42 is provided will be described with reference to FIGS. 4 and 5. In FIGS. 4 and 5, the broken line indicates the flow of the magnetic flux of the magnet. Further, FIG. 4 shows a no-load state, and FIG. 5 shows a high-load state.

In the no-load state or low-load state, as shown in FIG. 4, a part of the magnet magnetic flux goes to the first member 42, which has a high maximum magnetic permeability, a smaller magnetoresistance than the core piece 38, and a magnetic flux easily flows. It flows. As a result, a part of the magnet magnetic flux generated from one end (N pole) of the outer magnet 40 flows to the other end (S pole) of the outer magnet 40 without flowing to the stator 14. That is, a part of the magnetic flux of the magnet is short-circuited without flowing to the stator 14. By short-circuiting a part of the magnet magnetic flux in this way, the amount of magnet magnetic flux flowing to the stator 14, that is, the amount of interlinkage magnetic flux is significantly reduced as compared with the case where the first member 42 is not provided.

On the other hand, in a high load state in which a relatively large current is passed through the stator coil 28, as shown in FIG. 5, the magnet magnetic flux flowing through the first member 42 (short-circuited magnet magnetic flux) is significantly reduced, and most of the magnet magnetic flux is generated. Flows to the stator 14. This is because a large amount of current magnetic flux (magnetic flux having a high magnetic flux density) is generated in a high load state. The current magnetic flux generated in a large amount flows to the first member 42 with priority over the magnet magnetic flux. Further, since the saturation magnetization of the first member 42 is lower than the saturation magnetization of the core piece 38, the first member 42 is magnetically saturated before the core piece 38. As a result, in a high load state, the first member 42 tends to be magnetically saturated by the current magnetic flux. When the first member 42 is magnetically saturated by the current magnetic flux, most of the magnet magnetic flux does not flow to the first member 42 but flows to the stator 14. As a result, the amount of interlinkage magnetic flux can be kept large in a high load state.

That is, in the rotary electric machine 10 disclosed in the present application, a short-circuit member (first member 42) having a high maximum magnetic permeability and a small saturation magnetization is provided on the outer side in the radial direction of the outer magnet 40, so that the amount of interlinkage magnetic flux can be determined. It can be large in the high load state and high torque output state, and can be small in the no load state or low load state. As a result, in the outer rotor type rotary electric machine, it is possible to output a high torque in a high load state while suppressing the occurrence of back electromotive voltage and iron loss in a no-load or low-load state.

Next, the simulation results of the flow of magnetic flux in the rotary electric machine 10 illustrated in FIGS. 1 to 3 will be described. FIG. 6 shows the simulation results of the magnet magnetic flux in the no-load state, FIG. 7 shows the current magnetic flux in the high load state, and FIG. 8 shows the simulation results of the magnet magnetic flux in the high load state. In addition, in FIGS. 6 to 8, the density of black ink indicates the magnetic flux density, and the darker the color of black ink, the higher the magnetic flux density.

As shown in FIG. 6, in the no-load state, a part of the magnet magnetic flux generated by the outer magnet 40 passes from one end in the circumferential direction of the outer magnet 40, passes through the radial outside of the outer magnet 40, and the circumferential direction of the outer magnet 40 and the like. Head to the edge. That is, a part of the magnetic flux of the magnet is short-circuited without flowing to the stator 14. Then, by short-circuiting a part of the magnet magnetic flux, the amount of interlinkage magnetic flux can be reduced, and the counter electromotive voltage and iron loss can be effectively suppressed.

On the other hand, in a high load state, as shown in FIG. 7, the current magnetic flux flows into the first member 42, and the first member 42 is magnetically saturated. Therefore, as shown in FIG. 8, the magnet magnetic flux hardly flows into the first member 42, and most of it flows into the stator 14. As a result, in a high load state, the amount of interlinkage magnetic flux can be increased, and a high torque can be obtained.

In addition, the applicant of the present application simulated the amount of loss in each of the high load state and the low load state. As a result, the amount of loss in the high load state is almost the same regardless of the presence or absence of the short-circuit member (first member), but the amount of loss in the low load state is compared with the case where the short-circuit member is not provided. It was found that the value was reduced by about 10 to 20% when the short-circuit member was provided. That is, according to the rotary electric machine 10 disclosed in the present application, the loss amount in the no-load / low load state can be reduced while preventing the increase in the loss amount in the high load state, and the efficiency of the rotary electric machine 10 as a whole can be improved.

The configuration described so far is an example, and a short-circuit member made of a material having a higher maximum magnetic permeability than the core piece 38 and having a smaller saturation magnetization than the core piece 38 is arranged on the outer side in the radial direction of the outer magnet 40. If so, other configurations may be modified as appropriate.

For example, in the above description, the example in which the first member 42 that contacts the peripheral end surface of the core piece 38 is provided has been given, but instead of or in addition to the first member 42, it contacts the outer peripheral surface of the core piece 38. A second member may be provided. For example, as shown in FIG. 9, instead of providing the first member 42, a second member 46 that comes into contact with the outer peripheral surface of the core piece 38 may be provided. The second member 46 is made of a soft magnetic material having a higher maximum magnetic permeability than the core piece 38, and has a smaller saturation magnetization than the core piece 38 in contact with or adjacent to the core piece 38. The second member 46 may be provided separately from the fixing outer cylinder 44 that surrounds and fixes the outer circumference of the outer rotor 18, or the fixing outer cylinder 44 may be provided as the second member 46.

Even in this case, in the no-load / low-load state, a part of the magnet magnetic flux flows to the second member 46 and short-circuits, so that the amount of interlinkage magnetic flux can be reduced. Further, in a high load state, the second member 46 is magnetically saturated by the current magnetic flux, and the magnet magnetic flux is less likely to flow to the second member 46, so that the amount of interlinkage magnetic flux increases. That is, even in this case, the amount of interlinkage magnetic flux is small in the no-load / low-load state and large in the high-load state. As a result, it is possible to obtain a high torque in a high load state while suppressing a counter electromotive voltage and iron loss in a no-load / low load state.

However, the distance between the second member 46 and the outer magnet 40 is larger than that of the first member 42, and the magnet magnetic flux of the second member 46 is larger when the second member 46 is used than when the first member 42 is used. The short-circuit magnetic path becomes long and the magnetic resistance increases. As a result, the short circuit of the magnet magnetic flux disappears earlier (at the stage where the current value is low) and the amount of interlinkage magnetic flux becomes larger when the second member 46 is used than when the first member 42 is used. .. In other words, it can be said that providing the second member 46 in place of the first member 42 is advantageous for operation in a high load state.

On the other hand, when the first member 42 is used instead of the second member 46 as the short-circuit member, the magnetic resistance of the short-circuit magnetic path of the magnetic flux becomes small. Therefore, the short-circuit amount of the magnet magnetic flux can be increased, and the counter electromotive voltage and the iron loss in the no-load / low-load state can be suppressed more effectively than in the case of FIG. In other words, it can be said that the case where only the first member 42 is provided without providing the second member 46 is more advantageous for reducing the loss in the no-load / low-load state.

Further, the second member 46 may be provided together with the first member 42. In this case, the magnetic resistance of the short-circuit magnetic path of the magnetic flux is reduced, and the volume of the entire short-circuit member (first member 42 and second member 46) is increased, so that the saturation magnetization is increased. As a result, the short-circuit amount of the magnet magnetic flux can be increased, and the counter electromotive voltage and the iron loss in the no-load / low-load state can be suppressed more effectively than in the cases of FIGS. 2 and 8. Further, since the short-circuit member is not magnetically saturated until the load becomes relatively high, the state in which the counter electromotive voltage and the iron loss are suppressed can be maintained until the current becomes relatively high.

Further, in the description so far, the short-circuit members (first member 42, second member 46) are brought into contact with the core piece 38, but a gap G is provided between the short-circuit member and the core piece 38. May be good. That is, the short-circuit member and the core piece 38 may be configured to face each other in close proximity to each other without contacting each other. For example, as shown in FIG. 10, a gap G may be provided between the circumferential end of the first member 42 and the circumferential end of the core piece 38. Then, by adjusting the size of the gap G, the magnetic resistance of the short-circuit magnetic path of the magnetic flux can be adjusted, and by extension, the variable characteristic of the amount of interlinkage magnetic flux with respect to the load can be adjusted.

Further, the configurations of the rotary electric machine 10 described so far are all examples, and may be appropriately changed according to the required specifications. For example, the rotary electric machine 10 may be a single rotor type / outer rotor type rotary electric machine 10 that does not have an inner rotor 16. Further, the number of magnetic poles, the number of teeth, and the like mentioned in the above description may be changed as appropriate.

10 rotary electric machine, 14 stator, 16 inner rotor, 18 outer rotor, 20 rotary shaft, 22 connecting member, 26 stator core, 28 stator coil, 29 yoke, 30 inner teeth, 32 outer teeth, 38 core pieces, 40 outer magnets, 42 First member, 44 fixing outer cylinder, 46 second member.

Claims (5)

With the stator
An annular outer rotor arranged around the outer periphery of the stator, the outer rotor in which a plurality of core pieces and a plurality of outer magnets are alternately arranged in the circumferential direction.
A short-circuit member arranged on the outer side in the radial direction of the outer magnet and magnetically short-circuiting two core pieces located on both sides in the circumferential direction of the outer magnet.
With
The outer magnet is magnetized in the circumferential direction and in the opposite direction to the other outer magnets adjacent to the circumferential direction.
The short-circuit member is maximum permeability than the core pieces is a high soft magnetic material, rather small, the saturation magnetization than said core pieces,
The outer magnet is arranged so that its outer peripheral edge is radially inside the outer peripheral edge of the core piece.
A rotating electric machine that is characterized by that. The rotary electric machine according to claim 1.
Before SL shorting member has its circumferential end surface is disposed in contact or closely facing the circumferential end faces of the two core pieces, the contact with the maximum permeability than the core pieces are made of high soft magnetic material Or it contains a first member with a smaller saturation magnetization than the closely opposed core pieces,
A rotating electric machine that is characterized by that. The rotary electric machine according to claim 1 or 2.
The short-circuit member is arranged so that its inner peripheral surface is in contact with or close to the outer peripheral surfaces of the two core pieces, and is made of a soft magnetic material having a higher maximum magnetic permeability than the core piece and is in contact with or close to the core piece. Includes a second member with a smaller saturation magnetization than the opposing core pieces,
A rotating electric machine that is characterized by that. The rotary electric machine according to claim 3.
The second member is a rotary electric machine characterized in that it is a fixing outer cylinder that surrounds and fixes the outer circumference of the outer rotor. The rotary electric machine according to any one of claims 1 to 4.
A rotary electric machine characterized in that the short-circuit member and the core piece are close to each other with each other via a gap.