JP6357859B2 - Permanent magnet embedded rotary electric machine - Google Patents

Description

  The present invention relates to a rotating electrical machine having a rotor such as an electric motor or a generator, and more particularly to a permanent magnet embedded rotating electrical machine in which a permanent magnet is embedded in a rotor.

  In a permanent magnet embedded type rotating electrical machine, permanent magnets for a plurality of poles are embedded in the rotor along the circumferential direction of the rotor. In this permanent magnet embedded rotary electric machine, a magnet torque corresponding to the amount of magnetic flux generated from the permanent magnet and interlinked with the stator winding, and a reluctance torque that rotates the rotor core in a direction that reduces the magnetic resistance of the rotor core. Occurs in the rotor. Accordingly, the permanent magnet embedded rotary electric machine is widely used as a small high-output high-efficiency rotary electric machine.

  FIG. 11 is a cross-sectional view showing a configuration of a rotor 1 of a conventional permanent magnet embedded rotary electric machine. In the example shown in FIG. 11, the rotor 1 has a rotor core 2 formed by laminating rotor steel plates. In the rotor core 2, four sets of two slots 3 and 3 'are formed along the circumferential direction. Permanent magnets 4 and 4 'are inserted into the slots 3 and 3', respectively. A set of the two slots 3 and 3 ′ and the two permanent magnets 4 and 4 ′ constitutes one pole of the rotor core 2. The permanent magnets 4 and 4 ′ for one pole have the same polarity of magnetic poles with respect to the outer peripheral surface of the rotor core 2.

  Between the two slots 3 and 3 ′ constituting one pole, there is a center bridge 8 which is a thin portion of the rotor core 2. Further, between each slot 3 (3 ') and the outer periphery of the rotor core 2, there is a side bridge 9 (9') that is a thin portion of the rotor core 2.

  Of the inner wall surface of each slot 3 (3 ′), the inner wall surface on the inner peripheral side (the side closer to the rotation center) of the rotor 1 projects in the radial direction of the rotor 1 and the end surface of the permanent magnet 4 (4 ′). Two protrusions 7 (7 ′) that engage with the two are formed. These protrusions 7 (7 ') sandwich the permanent magnet 4 (4') from both sides in the circumferential direction of the rotor 1, and are positioned and fixed in the slot 3 (3 '). In each slot 3 (3 ′), an area facing the center bridge 8 includes an inner cavity 3a (3a ′) in which the permanent magnet 4 (4 ′) is not clogged, and the side bridge 9 (9 ′). There is an outer cavity 3b (3b ') in which the permanent magnet 4 (4') is not clogged.

A torque T shown in the following equation is generated in the rotor 1 of the permanent magnet embedded rotary electric machine.
T = P × ψa × Iq + P × (Ld−Lq) × Id × Iq (1)
In the above formula (1), P is the number of pole pairs of the rotor 1, ψa is the number of magnetic fluxes linked to the stator winding, Id and Iq are the d-axis component and q-axis component of the current flowing in the stator winding, Ld Is a d-axis inductance, and Lq is a q-axis inductance. Here, the d axis passes through the center bridge 8 between the two slots 3 and 3 'from the axis passing through the center of the magnetic pole of the rotor 1, that is, in the example of FIG. Is the axis. The q-axis is an axis in the direction between the magnetic poles that is deviated by 90 degrees in electrical angle from the d-axis. In the above formula (1), the first term on the right side is the magnet torque, and the second term on the right side is the reluctance torque.

  As shown in the above equation (1), the reluctance torque can be increased by increasing the difference between the d-axis inductance Ld and the q-axis inductance Lq. In the configuration shown in FIG. 11, the q-axis inductance Lq is small because the magnetic flux in the q-axis direction passes through a magnetic path with a low magnetic resistance made of the steel plate of the rotor core 2. On the other hand, the magnetic path of the magnetic flux in the d-axis direction has a high magnetic resistance because of the permanent magnets 4 and 4 '. For this reason, d-axis inductance becomes large. Therefore, according to the rotor 1 of the permanent magnet embedded rotary electric machine shown in FIG. 11, the reluctance torque can be increased.

  Further, in the permanent magnet embedded rotating electric machine shown in FIG. 11, when the rotor 1 rotates at a high speed, a centrifugal force is generated in the rotor core 2. In particular, the side bridge 9 (9 ') between the slot 3 (3') and the outer periphery of the rotor core 2 is subjected to shear stress due to centrifugal force. Further, when considering the increase in torque, it is necessary to increase the tightening allowance when the shaft 12 is press-fitted or shrink-fitted into the rotor core 2, so that the residual stress applied to the rotor core 2 after insertion of the shaft 12 is large. Become. In the permanent magnet embedded rotary electric machine shown in FIG. 11, shear stress and residual stress applied to the side bridges 9 and 9 ′ are alleviated by the center bridge 8 between the two slots 3 and 3 ′ in one pole. This permanent magnet embedded rotary electric machine is disclosed in, for example, Patent Document 1.

JP 2010-81754 A

  By the way, in the above-described conventional permanent magnet-embedded rotary electric machine, stress concentration tends to occur in the permanent magnet fixing protrusion 7 (7 '). For this reason, when the rotor 1 is rotated at a high speed or a large torque is generated, excessive stress is concentrated on the protrusion 7 (7 '), and in the worst case, the protrusion 7 (7') is damaged. In this case, as the number of protrusions increases, the number of parts that can be damaged increases, and the failure risk of the rotating electrical machine increases.

  Further, in the conventional permanent magnet embedded type rotating electric machine, in order to increase the reluctance torque, the current of the stator winding is increased to generate a d-axis direction magnetic flux that weakens the magnetic flux of the permanent magnet 4 (4 '). At this time, magnetic flux leakage from the N pole of the permanent magnet 4 (4 ′) through the center bridge 8 to the S pole of the permanent magnet increases, and the permanent magnet 4 (4 ′) demagnetizes. The problem of lowering the tolerance occurs.

  As a method for preventing the decrease in the demagnetization tolerance, a method of increasing the thickness of the permanent magnet 4 (4 ') in the magnetic axis direction is conceivable. However, when this method is adopted, the amount of necessary magnets increases, so that the material cost increases and the cost of the permanent magnet-embedded rotary electric machine increases.

  The present invention has been made in view of the circumstances as described above, and its purpose is to enable high-speed rotation and large torque, a low risk of failure, a high demagnetization resistance, and a small magnet amount. It is an object of the present invention to provide a configurable permanent magnet embedded rotary electric machine.

  The present invention relates to an embedded permanent magnet type rotating electrical machine in which a plurality of two permanent magnets are embedded per pole in the rotor along the circumferential direction of the rotor. 2 slots are formed in the circumferential direction of the rotor, and two permanent magnets are embedded in the two slots, and the two slots constituting the one pole are formed. Each accommodates a magnet support member made of a non-magnetic material in a region facing the thin portion of the rotor sandwiched between the two slots, and from the thin portion to the circumferential direction of the rotor. A protrusion that protrudes in the radial direction of the rotor and engages with an end face of the permanent magnet is provided at a distant position, and the position is fixed in the slot with the permanent magnet sandwiched between the magnet support member and the protrusion. Permanent magnet filling characterized by It provides real-type rotating electrical machine.

  According to the present invention, each of the two slots for constituting one pole has a magnet support member made of a non-magnetic material in a region facing the thin portion of the rotor sandwiched between the two slots. Contained. For this reason, the width | variety of the nonmagnetic area | region between two permanent magnets can be increased, and a demagnetization tolerance can be increased. Also, since each slot has only one protrusion, the risk of failure can be reduced when configuring a permanent magnet embedded rotating electrical machine that rotates at a high speed or a permanent magnet embedded rotating electrical machine that generates a large torque. it can. Therefore, according to the present invention, it is possible to realize a permanent magnet embedded type rotating electrical machine that is capable of high-speed rotation and large torque, has a low risk of failure, has a high demagnetization resistance, and can be configured with a small amount of magnets. Can do.

It is sectional drawing which shows the structure for 1 pole of the rotor which is 1st Embodiment of this invention. It is sectional drawing which shows the flow of the magnetic flux at the time of no load of the permanent magnet embedding type rotary electric machine which is a comparative example of the embodiment. It is sectional drawing which shows the flow of the magnetic flux at the time of load of the permanent magnet embedding type rotary electric machine. 4 is a graph showing a relationship between a distance between a permanent magnet and a center bridge and a demagnetization factor in the same embodiment. It is sectional drawing which shows the structure for 1 pole of the rotor which is 2nd Embodiment of this invention. It is sectional drawing which shows the structure for 1 pole of the rotor which is 3rd Embodiment of this invention. It is sectional drawing which shows the structure for 1 pole of the rotor which is 4th Embodiment of this invention. It is sectional drawing which shows the structure for 1 pole of the rotor which is 5th Embodiment of this invention. It is sectional drawing which shows the structure for 1 pole of the rotor which is 6th Embodiment of this invention. It is sectional drawing which shows the structure for 1 pole of the rotor which is 7th Embodiment of this invention. It is sectional drawing which shows the structure of the rotor of the conventional permanent magnet embedding type rotary electric machine.

  Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
FIG. 1 is a cross-sectional view showing the configuration of one pole of a rotor 1A of a permanent magnet embedded rotary electric machine according to a first embodiment of the present invention. In FIG. 1, illustration of a rotating shaft and a stator that the rotor 1A has in the center is omitted.

  The rotor 1A has a rotor core 2A in which high permeability steel plates are stacked in the direction of the rotation axis. In addition to this structure, the rotor core 2A may be configured by molding magnetic iron powder into a necessary shape. The rotor core 2A is formed with two slots 3 and 3 'arranged in the circumferential direction of the rotor core 2A in order to form one pole. These two slots 3 and 3 'sandwich a center bridge 8 which is a thin portion of the rotor core 2A. Further, between the ends of the two slots 3 and 3 ′ opposite to the center bridge 8 and the outer periphery of the rotor core 2A are side bridges 9 and 9 ′ that are thin portions of the rotor core 2A. ing. In the rotor core 2A, the region on the inner peripheral side of the permanent magnets 4 and 4 'and the outer peripheral edge 15 on the outer peripheral side are connected to each other via the center bridge 8 and the side bridges 9 and 9'.

  In the present embodiment, the two slots 3 and 3 ′ have end portions near the center bridge 8 close to the rotation center axis (not shown) of the rotor core 2A, and end portions near the side bridges 9 and 9 ′. Is located near the outer periphery of the rotor core 2A, and has a V-shape as a whole when viewed with the rotation center axis facing down. Two permanent magnets 4 and 4 'are embedded in the two slots 3 and 3' for one pole having the V shape. These permanent magnets 4 and 4 'have magnetic poles of the same polarity facing the outer peripheral surface of the rotor core 2A.

  In each slot 3 (3 '), a magnet support member 10 (10') is accommodated in a region 3a (3a ') facing the center bridge 8. The magnet support members 10 and 10 'are in contact with the inner ends 6 and 6' of the permanent magnets 4 and 4 'facing each other. The magnet support member 10 (10 ') is made of a nonmagnetic material such as insulating paper or resin in order to prevent magnetic flux leakage.

  On the other hand, on the inner wall of the rotor core 2A in each slot 3 (3 ′) (on the side close to the rotation center axis), it protrudes in the radial direction of the rotor core 2A at a position away from the center bridge 8. A protrusion 7 (7 ') is formed. The protrusion 7 (7 ') is engaged with the outer end 5 (5') of the permanent magnet 4 (4 ') near the poles of the rotor core 2A.

  In each slot 3 (3 ′), the permanent magnet 4 (4 ′) is positioned between both sides of the rotor core 2A in the circumferential direction by the magnet support member 10 (10 ′) and the protrusion 7 (7 ′). It is fixed.

  In each slot 3 (3 ′), the region from the side bridge 9 (9 ′) to the protrusion 7 (7 ′) is an outer cavity 3b (3b ′) in which the permanent magnet 4 (4 ′) is not clogged. Yes.

  In the present embodiment, the permanent magnet 4 (4 ′) has the outer end 5 (5 ′) near the pole of the rotor core 2A supported by the protrusion 7 (7 ′), while the pole of the rotor core 2A. The inner end 6 (6 ′) near the center is supported by a magnet support member 10 (10 ′). Thus, in this embodiment, there is only one protrusion for supporting the permanent magnet 4 (4 ') per slot. Therefore, compared to the conventional example (FIG. 11) having two protrusions per slot, the rotor core 2A in the present embodiment has a reduced risk of failure because the number of protrusions on which stress concentration easily occurs during high-speed rotation. Has the effect of reducing. Even if the protrusions are provided at two locations per slot, in this case, the stress at the time of high-speed rotation is distributed to the protrusions and the magnet support material 10 (10 ′), so that the risk of damage to the protrusions is reduced and the rotation is reduced. The risk of electric machine failure is also reduced.

  In this embodiment, since the magnet support member 10 (10 ′) made of a nonmagnetic material is interposed between the permanent magnet 4 (4 ′) and the center bridge 8 in each slot 3 (3 ′), The width of the nonmagnetic region between the two permanent magnets 4 and 4 ′ can be increased, and the demagnetization tolerance of the permanent magnets 4 and 4 ′ can be increased.

  Hereinafter, this effect will be described with reference to a comparative example. 2 and 3 show, as a comparative example, the flow of magnetic flux in a permanent magnet embedded type rotating electrical machine using a rotor 1A 'having a configuration in which the magnet support member 10 (10') is not provided in FIG. Here, FIG. 2 shows the flow of magnetic flux when there is no load, and FIG. 3 shows the flow of magnetic flux when a current is passed through the stator winding in the stator winding slot 14. As shown in FIG. 2, when no load is applied, only the magnetic flux of the permanent magnet 4 (4 ') is generated. In this case, the magnetic flux leakage through the center bridge 8 is slight and hardly occurs. However, when a load is applied to the permanent magnet embedded rotary electric machine and a current is passed through the stator winding in the stator winding slot 14, as shown in FIG. Unlike the line in FIG. 2, magnetic flux leakage occurs in the center bridge 8.

  Magnetic flux leakage at the center bridge 8 is more likely to occur as the permanent magnet 4 (4 ') is closer to the center bridge 8, and accordingly, demagnetization of the permanent magnet 4 (4') is likely to occur. Therefore, the demagnetization resistance of the permanent magnet 4 (4 ') is reduced, and it is difficult to increase the torque. Therefore, in order to increase the demagnetization tolerance, the thickness of the center bridge 8 is reduced so as to increase the magnetic flux by increasing the thickness of the permanent magnet 4 (4 ′) in the magnetic axis direction or to prevent magnetic flux leakage. Is required. However, if the thickness of the permanent magnet 4 (4 ') is increased, the amount of necessary magnets increases, the material cost increases, and the manufacturing cost of the permanent magnet embedded rotary electric machine increases. On the other hand, when the width of the center bridge 8 is narrowed, the strength of the center bridge 8 is weakened, causing a problem that the permanent magnet embedded rotary electric machine cannot cope with high-speed rotation.

  Therefore, in the present embodiment, as shown in FIG. 1, a magnet support member 10 (10 ′) made of a non-magnetic material between the permanent magnet 4 (4 ′) and the center bridge 8 in the slot 3 (3 ′). Is inserted to increase the width of the non-magnetic region between the two permanent magnets 4 and 4 '.

  FIG. 4 is a graph showing the relationship between the distance between the permanent magnets 4 and 4 ′ and the center bridge 8 and the demagnetization factor. This graph was obtained by magnetic field analysis using the finite element method by the present inventors. In FIG. 4, the demagnetization factor on the vertical axis is a value indicating the ratio of demagnetization, and the demagnetization factor and the demagnetization tolerance are in an inversely proportional relationship. That is, when the demagnetization factor decreases, the demagnetization tolerance increases, and when the demagnetization factor increases, the demagnetization tolerance decreases.

  In this embodiment, as shown in FIG. 1, magnet support members 10 and 10 ′ made of a nonmagnetic material are inserted between the permanent magnets 4 and 4 ′ and the center bridge 8, respectively. The distance between 'and the center bridge 8 is increased. Therefore, according to the present embodiment, it is possible to increase the demagnetization tolerance by decreasing the demagnetization factor.

  As described above, according to the present embodiment, in each of the two slots 3 and 3 ′ for constituting one pole, the magnet support member 10 (10) made of a nonmagnetic material in the region facing the center bridge 8. Since each of ') is accommodated, the width of the nonmagnetic region between the two permanent magnets 4 and 4' can be increased, and the demagnetization resistance can be increased. Further, since each slot 3 and 3 ′ is provided with only one protrusion 7 (7 ′), a permanent magnet embedded rotary electric machine that rotates at a high speed and a permanent magnet embedded rotary electric machine that generates a large torque are constituted. In case the failure risk can be reduced. Therefore, according to this embodiment, a permanent magnet embedded type rotating electrical machine that can be configured with a small amount of magnets that can rotate at high speed and increase torque, has a low risk of failure, has a high demagnetization resistance, and can be realized. be able to.

Second Embodiment
FIG. 5 is a cross-sectional view showing a configuration of one pole of a rotor 1B of a permanent magnet embedded rotary electric machine according to a second embodiment of the present invention. The rotor 1B has a rotor core 2B. Similar to the first embodiment, the rotor core 2B is formed with two slots 3 and 3 ′ as one pole.

  The difference between the rotor core 2A of the first embodiment and the rotor core 2B of the present embodiment is the difference in the arrangement of the slots 3 and 3 '. In other words, in the present embodiment, the two slots 3 and 3 ′ have their respective end portions near the center bridge 8 positioned near the outer periphery of the rotor core 2 </ b> B, and the respective end portions on the opposite side to the center bridge 8. It is located near the rotation center axis of 2B, and has an inverted V shape as a whole when viewed with the rotation center axis facing downward.

  Also in this embodiment, the same effect as the first embodiment can be obtained. Further, according to the present embodiment, since the slots 3 and 3 ′ are arranged in an inverted V shape in the rotor core 2 </ b> B, still another effect can be obtained. This effect will be described as follows.

  First, in an interference fitting process of a shaft (not shown) to the rotor 1B, residual stress remains in the rotor steel material in the circumferential direction. This residual stress remains even during high-speed rotation of the rotor 1B. When the inventors of the present application calculated by the finite element method, it was confirmed that this residual stress hardly occurs on the circumference having the same radius as that of a portion such as a hole or a depression in the rotor steel (that is, There is no hole, no depression, and no stress is left unless it is a ring-shaped part).

  Therefore, in the rotor core 2A in the first embodiment, the inner cavities 3a and 3a 'facing the center bridge 8 in the slots 3 and 3' are closest to the rotation center axis of the rotor core 2A. For this reason, residual stress concentrates in the circumference of the circle in contact with the inner cavities 3a and 3a '. On the other hand, in the rotor core 2B according to the present embodiment, residual stress is concentrated in the circumference of a circle inscribed in each of the end portions on the opposite side of the center bridge 8 in the slots 3 and 3 '.

  On the other hand, when the rotor 1B rotates at high speed, tensile stress (centrifugal stress) due to centrifugal force is generated in the center bridge 8. In the rotor core 2A in the first embodiment, the position of the center bridge 8 is close to the inscribed circle where the residual stress is concentrated, whereas in the rotor core 2B in the present embodiment, the position of the center bridge 8 is It moves away from the inside of the inscribed circle where the residual stress is concentrated to the outside in the radial direction of the rotor core 2B.

  As described above, according to the present embodiment, the center bridge 8 where the tensile stress due to the centrifugal force is concentrated during the high speed rotation of the rotor 1B is away from the inscribed circle where the residual stress due to the interference fitting process is concentrated. The strength of the center bridge 8 when the child 1B rotates at high speed can be increased. Therefore, it can be said that the rotor 1B according to the present embodiment is advantageous in terms of high-speed rotation and large torque compared to the rotor 1A of the first embodiment.

<Third Embodiment>
FIG. 6 is a cross-sectional view showing a configuration of one pole of a rotor 1C of a permanent magnet embedded rotary electric machine according to a third embodiment of the present invention. Similar to the first embodiment, the rotor core 2C of the rotor 1C is formed with two slots 3 and 3 'for one pole. In the rotor core 2C in the present embodiment, the slots 3 and 3 ′ for one pole are arranged in a single character shape. Other points are the same as in the first embodiment. Also in this embodiment, the same effect as the first embodiment can be obtained.

<Fourth embodiment>
FIG. 7 is a cross-sectional view showing a configuration of one pole of a rotor 1D of a permanent magnet embedded rotary electric machine according to a fourth embodiment of the present invention. In the rotor core 2D of the rotor 1D, two slots 3 and 3 ′ are formed as one pole. As in the first embodiment, the two slots 3 and 3 ′ are V-shaped as a whole when viewed from the center of the rotation axis. Unlike the first embodiment, the rotor 1D in the present embodiment has notches 11 and 11 ′ that allow the outer cavities 3b and 3b ′ in the slots 3 and 3 ′ to communicate with the outside of the rotor 1D, respectively. Yes. Other configurations are the same as those in the first embodiment. Also in this embodiment, the same effect as the first embodiment can be obtained.

  The rotor core 2D in this embodiment has a configuration in which slots 3 and 3 'communicate with the outer periphery of the rotor core 2D. Hereinafter, the reason why this configuration is adopted will be described.

  When the rotor 1D rotates at a particularly high speed, a strong centrifugal force is generated in each part of the rotor core 2D. At this time, if the rotor cores 2A to 2C have the center bridge 8 and the side bridges 9 and 9 'as in the first embodiment, the second embodiment, and the third embodiment, the center bridge 8 and the side bridge A large stress is generated in the bridges 9 and 9 '. In this case, a tensile stress acts on the center bridge 8 due to the centrifugal force generated by the rotation of the rotors 1A to 1C, whereas shear stress occurs on the side bridges 9 and 9 '. For this reason, in order to prevent damage to the rotors 1A to 1C due to high-speed rotation, it is necessary to sufficiently increase the strength of the side bridges 9 and 9 'rather than the center bridge 8. However, it is generally difficult to design the strength of the center bridge 8 and the side bridges 9 and 9 '.

  Therefore, in the present embodiment, a configuration in which the slots 3 and 3 'communicate with the outer periphery of the rotor 1D, that is, a configuration without the side bridges 9 and 9' in the first embodiment is adopted as the configuration of the rotor core 2D. According to this embodiment, since the rotor core 2D does not have the side bridges 9 and 9 'on the outermost periphery, no assembly residual stress remains on the outermost periphery of the rotor core 2D. The stress generated by the centrifugal force during rotation of the rotor 1D is concentrated on the center bridge 8. However, since the stress acting on the center bridge 8 is a tensile stress, the center bridge 8 is damaged by adjusting the width of the center bridge 8 or the like. It is easy to deal with such that Moreover, the configuration of the rotor 1D in which the outer cavities 3b and 3b 'communicate with the outermost periphery of the rotor core 2D provides the following significant advantages.

  The rotor core 2D in the present embodiment has fewer magnetic flux leakage paths than the rotor cores 2A to 2C of the first, second, and third embodiments having the side bridges 9 and 9 '. For this reason, the magnetic fluxes of the permanent magnets 4 and 4 'are easily interlinked with the stator winding, which contributes to an increase in torque.

  Furthermore, the rotor core 2D of this embodiment has an advantage also in the cooling surface. That is, the rotor core 2D of this embodiment has good ventilation in the direction of the rotation axis, which is advantageous for cooling, particularly for magnet cooling. Therefore, by adopting the rotor core 2D according to the present embodiment, it is possible to relax the regulations regarding the motor capacity.

<Fifth Embodiment>
FIG. 8 is a cross-sectional view showing a configuration of one pole of a rotor 1E of a permanent magnet embedded rotary electric machine that is a fifth embodiment of the present invention. In the rotor core 2E of the rotor 1E, two slots 3 and 3 ′ are formed as one pole. As in the second embodiment, the slots 3 and 3 ′ for one pole are arranged in an inverted V shape. Unlike the second embodiment, the rotor core 2E according to the present embodiment has notches 11 and 11 for communicating the outer cavities 3b and 3b ′ of the slots 3 and 3 ′ with the outer periphery of the rotor core 2E, respectively. 'have. Other configurations are the same as those of the second embodiment.

  According to this embodiment, the same effect as the second embodiment can be obtained. Further, according to the present embodiment, as in the fourth embodiment, since the rotor core 2E is not provided with a side bridge, the same effects as in the fourth embodiment can be obtained. In the present embodiment, since there is no side bridge and the slots 3 and 3 ′ are arranged in an inverted V shape, the permanent magnets 4 and 4 ′ are arranged on the outer peripheral edge portion outside the slots 3 and 3 ′. 15 is supported by uniform stress over the entire length. For this reason, it is hard to generate | occur | produce a stress inside permanent magnet 4 and 4 ', and it can protect permanent magnet 4 and 4' from a failure | damage.

<Sixth Embodiment>
FIG. 9 is a cross-sectional view showing a configuration of one pole of a rotor 1F of a permanent magnet embedded rotary electric machine according to a sixth embodiment of the present invention. Similar to the third embodiment, the rotor core 2F of the rotor 1F has two slots 3 and 3 ′ arranged in a single character as one pole. Similarly to the fourth embodiment, the rotor core 2F in the present embodiment has notches 11 and 11 that communicate the outer cavities 3b and 3b ′ of the slots 3 and 3 ′ with the outer periphery of the rotor core 2F, respectively. 'have. Other configurations are the same as those of the third embodiment. According to this embodiment, the same effect as the third embodiment and the fourth embodiment can be obtained.

<Seventh embodiment>
FIG. 10 is a cross-sectional view showing a configuration for one pole of a rotor 1G of a permanent magnet embedded rotary electric machine according to a seventh embodiment of the present invention. The present embodiment is a modification of the fifth embodiment.

  In the rotor core 2G of the rotor 1G, the slots 3 and 3 'for one pole are arranged in an inverted V shape as in the fifth embodiment. The outer peripheral edge portion 15 for one pole has a substantially arc-shaped cross-sectional shape, and is connected to the core portion of the rotor core 2G via the center bridge 8 at the center in the rotation direction of the rotor core 2G. The outer peripheral surface of the outer peripheral edge portion 15 has a radius of curvature smaller than the distance from the rotation center axis Q to the outermost peripheral portion of the rotor core 2G. This is because the harmonic component of torque is reduced by making the outer peripheral edge portion 15 in such a shape, and the fundamental component of torque generated in the rotor 1G is increased by the reduced amount. Note that the radius of curvature of a part of the outer peripheral edge portion 15 instead of the entire outer peripheral edge portion 15 may be made smaller than the distance from the rotation center axis Q to the outermost peripheral portion of the rotor.

  As in the fifth embodiment, a magnet support member 10 (10 ') made of a nonmagnetic material is inserted into the inner cavity 3a (3a') facing the center bridge 8 in the slot 3 (3 '). On the other hand, a protrusion 17 (17 ') protruding in the direction of the rotation axis Q of the rotor 1G is formed in the vicinity of the end of the outer peripheral edge 15 in the inner wall of each slot 3 (3'). The protrusion 17 (17 ') is engaged with the outer end 5 (5') of the permanent magnet 4 (4 ') near the poles of the rotor 1G. In the present embodiment, the permanent magnet 4 (4 ′) is sandwiched by the magnet support member 10 (10 ′) and the protrusion 17 (17 ′) from both sides in the circumferential direction of the rotor 1G and placed in the slot 3 (3 ′). Positioning is fixed. In the present embodiment, the position of the protrusion 17 (17 ′) is different from that of the fifth embodiment. Except for this point, a configuration for fixing the permanent magnet 4 (4 ′) in the slot 3 (3 ′). Is basically the same as in the first to sixth embodiments. Therefore, according to this embodiment, the same effect as the first to sixth embodiments can be obtained.

  The outer cavity 3b (3b ') of the slot 3 (3') is recessed toward the rotation center axis Q as shown by a broken line 3w in FIG. As described in the second embodiment, since the slots 3 and 3 ′ are arranged in an inverted V shape in this embodiment, as shown in FIG. 10, the rotation center axis Q is the center. Residual stress is concentrated in a region on the circumference of the inscribed circle 21 in contact with the outer cavity 3b (3b ′) of the slot 3 (3 ′).

  On the other hand, since the slots 3 and 3 ′ are arranged in an inverted V shape, the inner peripheral end 8 b of the center bridge 8 is located away from the inscribed circle 21 when viewed from the rotation center axis Q. For this reason, also in this embodiment, the effect similar to the said 2nd Embodiment is acquired.

  One feature of the present embodiment is a q-axis protrusion 19. The q-axis protrusion 19 protrudes in the centrifugal direction (direction away from the rotation center axis Q) through the gap between the two outer peripheral edge portions 15 at the center position between the poles of the rotor 1G.

  In the present embodiment, by providing the q-axis protrusion 19, the magnetic resistance of the magnetic path of the magnetic flux in the q-axis direction can be lowered and the reluctance torque can be increased. Therefore, according to the present embodiment, it is possible to realize a permanent magnet embedded rotary electric machine that can obtain a larger torque than the first to sixth embodiments.

1A, 1B, 1C, 1D, 1E, 1F, 1G ... Rotor, 2A, 2B, 2C, 2D, 2E, 2F, 2G ... Rotor core, 3, 3 '... Slot, 3a, 3a' ... ... inner cavity, 3b, 3b '... outer cavity, 4, 4' ... permanent magnet, 5, 5 '... permanent magnet outer peripheral end, 6, 6' ... permanent magnet inner peripheral end , 7, 7 ', 17, 17' ... projection, 8 ... center bridge, 9, 9 '... side bridge, 10, 10' ... magnet support member, 11, 11 '... notch, 12 ...... Shaft, 13 ... Stator, 14 ... Slot for stator winding, 15 ... Outer peripheral edge, 19 ... q-axis projection.

Claims (4)

In a permanent magnet embedded rotary electric machine in which a plurality of two permanent magnets per pole are embedded in the rotor along the circumferential direction of the rotor,
The rotor has two slots arranged in the circumferential direction of the rotor to form one pole, and two permanent magnets are embedded in the two slots,
Each of the two slots constituting the one pole communicates with the outer periphery of the rotor on the outer side in the rotation direction, and is not in a region facing the thin portion of the rotor sandwiched between the two slots. Each of the magnet support members made of a magnetic material is accommodated, and a protrusion that protrudes in the radial direction of the rotor and engages with the end surface of the permanent magnet is provided at a position away from the thin portion in the circumferential direction of the rotor. and, the magnet support member and the Ri name located fixed to the inside slot across the permanent magnet by the projections, of the two slots constituting the one pole around the rotation center axis of the rotor A permanent magnet-embedded rotary electric machine having the thin-walled portion in the outer circumferential direction of the rotor rather than a contact circle . 2. The permanent magnet embedded electric motor according to claim 1, wherein the rotor has a q-axis protrusion that protrudes in a direction away from a rotation center axis of the rotor between adjacent poles. The permanent magnet-embedded rotary electric machine according to claim 1, wherein the magnet support member is an insulating paper. The permanent magnet-embedded rotating electrical machine according to claim 1, wherein the magnet support member is a resin.

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