JP4661972B2 - Rotor - Google Patents

Description

  The present invention relates to a rotor, and more particularly to the shape of a rotor core.

  Patent Document 1 describes a rotor that reduces cogging torque, reduces the harmonic content of the induced voltage, and reduces vibration and noise. The rotor has a rotor core and a plurality of permanent magnets. The plurality of permanent magnets are annularly arranged around the rotation axis. The plurality of permanent magnets are embedded in the rotor core. The diameter of the outer peripheral side surface of the rotor core is small at both ends of the permanent magnet.

JP 2005-52825 A

  However, in Patent Document 1, no consideration is given to vibration caused by the swing of the rotor, and such vibration cannot be reduced. The term “rotation of the rotor” as used herein refers to a phenomenon in which the center of the rotor rotates around the center of the stator due to, for example, a shift between the center of the rotor and the center of the stator.

  Such swinging increases the electromagnetic excitation force in the radial direction, thereby increasing vibration.

  Then, an object of this invention is to provide the rotor which can suppress the vibration resulting from the whirling of a rotor.

A first aspect of the rotor according to the present invention is a permanent magnet (20) arranged in a ring around a predetermined axis (P), and magnetic poles having different polarities around the axis by the permanent magnet. 2N (N is a natural number) magnetic pole faces (11) presented in a radial direction centered on the axis, and provided on the magnetic pole face side with respect to the permanent magnet, and an angle around the axis in ((N + 1) × 2) and a core rotor (10) having at least one exists magnetic barrier portion to each of the equally divided areas (111), each present in the area ((N + 1) × 2) The magnetic barrier portions are provided at equal intervals in the circumferential direction centered on the axis (P), and the magnetic barrier portions are provided at both ends of the permanent magnet in the circumferential direction in the circumferential direction. Different from the gap (121) .

The 2nd aspect of the rotor concerning this invention is a rotor concerning a 1st aspect, Comprising: The said magnetic barrier part (111) is a groove part (112) provided in the said magnetic pole surface.

A third aspect of the rotor according to the present invention is the rotor according to the first aspect, wherein the magnetic barrier portion (111) is a nonmagnetic material provided between the permanent magnet and the magnetic pole surface. (113).

A fourth aspect of the rotor according to the present invention is the rotor according to the first aspect, wherein the rotor core further includes a plurality of electromagnetic steel plates stacked in a direction along the axis (P). And at least a plurality of the plurality of electromagnetic steel sheets are fitted with each other and provided with irregularities (114) for fixing in the direction along the axis, and the irregularities are provided as the magnetic barrier portions (111). Function.

A fifth aspect of the rotor according to the present invention is the rotor according to the third or fourth aspect, wherein the magnetic barrier portion (111) is a circle having the largest diameter passing through the permanent magnet (20). R1) is provided on the opposite side of the axis (P).

  According to the first aspect of the rotor according to the present invention, the rotating electrical machine can be realized by arranging the stator so as to face the magnetic pole surface via the air gap in the radial direction.

  In such a rotating electrical machine, the rotor core is provided with at least one magnetic barrier portion in each of the regions obtained by equally dividing the circumference of the axis by ((N + 1) × 2). Therefore, the magnetic barrier portion has a period of the (N + 1) -order harmonic component of the magnetic flux density that the rotor supplies to the stator (the fundamental wave is a sine wave having one period around the axis as one period). Therefore, the (N + 1) -order harmonic component can be reduced in a relatively balanced manner.

The (N + 1) -order harmonic component is generated due to the swing of the rotor, and the harmonic component increases the (2N + 1) -order electromagnetic excitation force. The (2N + 1) th order electromagnetic excitation force is the main factor that increases the vibration. Since the (N + 1) th order harmonic component of the magnetic flux density can be reduced, the vibration caused by the swing of the rotor can be more efficiently performed. Can be reduced. In addition, since the magnetic barrier portion is provided at a position corresponding to the period of the (N + 1) -order harmonic component, the (N + 1) -order harmonic component can be appropriately reduced.

According to the second aspect of the rotor according to the present invention, the air gap between the rotor and the stator can be increased at the position where the groove is provided, so that the groove can function as a magnetic barrier.

According to the third aspect of the rotor according to the present invention, since the magnetic barrier portion is provided away from the magnetic pole surface, the magnetic barrier portion is provided between the rotor side surface (magnetic pole surface) and the stator. Does not interfere with air gap measurement. Therefore, the air gap can be measured regardless of the position of the magnetic barrier portion.

According to the 4th aspect of the rotor concerning this invention, since a magnetic barrier part exhibits the function which fixes an electromagnetic steel plate, and the function of a magnetic barrier, the exclusive fixing | fixed part which exhibits each function, a magnetic barrier Compared with the case where a part is provided, the manufacturing cost can be reduced.

According to the fifth aspect of the rotor of the present invention, it is possible to increase the amount by which the (N + 1) -order harmonic component is reduced by the magnetic barrier portion.

It is sectional drawing which shows the notional structure of the rotor concerning 1st Embodiment. It is a figure for demonstrating a whirling. It is a figure for demonstrating a whirling. It is a figure for demonstrating a whirling. It is a figure for demonstrating a whirling. It is a graph which shows electromagnetic excitation force. It is a graph which shows the component which contributes to a torque among magnetic flux densities. It is sectional drawing which shows the notional structure of the rotor concerning 2nd Embodiment. It is a graph which shows the relationship between the distance from a center to a magnetic barrier part, and the ratio of the 3rd harmonic component with respect to the component which contributes to a torque among magnetic flux densities. It is sectional drawing which shows the notional structure of the rotor concerning 3rd Embodiment. It is sectional drawing which shows the notional structure of a compressor provided with the motor which has this rotor.

First embodiment.
<Configuration of rotor>
FIG. 1 shows a cross section perpendicular to an axis P (described later) of the rotor 1. As illustrated here, the rotor 1 includes a rotor core 10 and a plurality of permanent magnets 20.

  The plurality of permanent magnets 20 are, for example, rare earth magnets (for example, rare earth magnets mainly composed of neodymium, iron, and boron), and are arranged in a ring around a predetermined axis P. In the illustration of FIG. 1, each permanent magnet 20 has a rectangular parallelepiped plate shape. Each permanent magnet 20 has its thickness direction in the radial direction centered on the axis P (hereinafter simply referred to as the radial direction) in the center in the circumferential direction centered on the axis P (hereinafter simply referred to as the circumferential direction). ). Each permanent magnet 20 is not necessarily arranged in the shape shown in FIG. For example, each permanent magnet 20 is viewed in a direction along the axis P (hereinafter simply referred to as the axial direction), and is opposite to the axis P (hereinafter also referred to as the outer peripheral side) or the axis P side (hereinafter also referred to as the inner peripheral side). It may have a V shape that opens to the outer peripheral side or an inner peripheral side.

  In the illustration of FIG. 1, any pair of permanent magnets 20 adjacent in the circumferential direction are arranged facing the magnetic pole surfaces 20 a having different polarities toward the outer peripheral side. Thereby, each permanent magnet 20 functions as a so-called field magnet that supplies field magnetic flux to a stator (not shown).

  In the illustration of FIG. 1, four permanent magnets 20 (so-called four-pole rotor 1) are illustrated, but the rotor 1 may have two permanent magnets 20 and may have six or more permanent magnets. The magnet 20 may be included. In the illustration of FIG. 1, each of the four permanent magnets 20 constitutes one field magnetic pole. However, for example, one field magnetic pole may be constituted by a plurality of permanent magnets 20. In other words, for example, each permanent magnet 20 in FIG. 1 may be divided into a plurality of permanent magnets.

  The rotor core 10 is made of a soft magnetic material (for example, iron). In the illustration of FIG. 1, the rotor core 10 has, for example, a substantially cylindrical shape with the axis P as the center.

  The rotor core 10 is provided with a plurality of magnet storage holes 12 in which a plurality of permanent magnets 20 are stored. Each magnet storage hole 12 has a shape that matches the shape and arrangement of each permanent magnet 20. In the example of FIG. 1, four magnet storage holes 12 are formed.

Each permanent magnet 20 forms 2p (p is an integer of 1 or more) magnetic pole surfaces on the outer peripheral side surface 11 of the rotor core 10 that present magnetic poles having different polarities around the axis in the radial direction. Is done. In the illustration of FIG. 1, two permanent magnets 20 exhibiting a positive magnetic pole surface 20 a each form a positive magnetic pole surface on the outer peripheral side surface 11, and two permanent magnets 20 presenting a negative magnetic pole surface 20 a are respectively outer peripheral side surfaces 11. The magnetic pole surface of the negative electrode is formed. Therefore, in the illustration of FIG. 1, four magnetic pole surfaces are formed on the outer peripheral side surface 11.

  The rotor core 10 may be composed of, for example, electromagnetic steel plates stacked in the axial direction. As a result, the electrical resistance in the axial direction of the rotor core 10 can be increased, so that the generation of eddy currents due to the magnetic flux flowing through the rotor core 10 can be reduced. Moreover, the rotor core 10 may be configured by a dust core formed intentionally including an electrical insulator (for example, resin). Since the insulator is included, the electric resistance of the dust core is relatively high, and the generation of eddy current can be reduced.

  The rotor core 10 may be provided with a substantially cylindrical shaft through-hole 13 centered on the axis P, for example. The side surface forming the shaft through hole 13 can be grasped as the inner peripheral side surface with respect to the outer peripheral side surface 11. A shaft (not shown) is fitted into the shaft through-hole 13 to fix the rotor core 10 and the shaft. When the shaft through hole 13 is not provided, for example, end plates (not shown) may be provided on both sides of the rotor core 10 in the axial direction, and the shaft may be attached to the end plate.

  In the illustration of FIG. 1, the rotor core 10 is provided with air gaps 121 on both sides in the circumferential direction of the permanent magnet 20 forming one field magnetic pole. The air gap 121 extends from both sides of the permanent magnet 20 to the outer peripheral side. The gap 121 can suppress a short circuit of the magnetic flux between the magnetic pole surface 20a on the outer peripheral side and the magnetic pole surface 20b on the inner peripheral side of the permanent magnet 20.

  In the illustration of FIG. 1, the gap 121 is connected to the magnet storage hole 12, but may be separated from the magnet storage hole 12. In this case, since a part of the rotor core 10 is interposed between the gap 121 and the magnet storage hole 12, the strength of the rotor core 10 can be improved.

  In the illustration of FIG. 1, a rib portion 14 as a part of the rotor core 10 is interposed between the permanent magnets 20 adjacent in the circumferential direction. The rib portion 14 can improve so-called q-axis reluctance. Therefore, the difference between the d-axis reluctance and the q-axis reluctance can be increased, and as a result, the reluctance torque can be improved.

In the illustration of FIG. 1, the rib portion 14 and the core portion (a part of the rotor core 10) existing on the outer peripheral side of the permanent magnet 20 are connected to each other on the outer peripheral side of the gap 121. The connecting portion 15 is also formed as a part of the rotor core 10. Thereby, the intensity | strength of the core 10 for rotors can be improved. It is desirable that the thickness of the connecting portion in the radial direction is small enough to be easily magnetically saturated by the magnetic flux passing through the connecting portion. Thus, the magnetic flux between the pole faces 20a, 20 b of the permanent magnet 20, the core portion of the outer peripheral side of the permanent magnet 20, connection 15, the rib portion 14, the core portion of the inner peripheral side of the permanent magnet 20 (the rotor some of use core 10) can be prevented from being short-circuited via.

  The rotor core 10 is provided with a magnetic barrier 111. The magnetic barrier portion 111 is provided on the outer peripheral side surface 11 side with respect to the permanent magnet 20. In the illustration of FIG. 1, the magnetic barrier portion 111 is shown as a groove portion 112 formed on the outer peripheral side surface 11. In the illustration of FIG. 1, the groove 112 has a surface 112a along the circumferential direction, and a surface 112b extending from both ends in the circumferential direction of the surface 112a to the outer peripheral side in the radial direction, and the surface 112b is the surface 112a. It is connected with the outer peripheral side surface 11 other than the groove part 112 on the opposite side.

  At least one magnetic barrier portion 111 (in the example of FIG. 1, a groove portion 112) is provided in each of the regions equally divided by the angle around the axis P ((p + 1) × 2). In FIG. 1, an example of such a region is shown as a region sandwiched between two adjacent members out of a radial two-dot broken line centered on the axis P.

  In the example of FIG. 1, the magnetic barrier portions 111 are provided by the number calculated by doubling the value obtained by adding 1 to the number of magnetic pole pairs (hereinafter referred to as the number of pole pairs) p of the rotor 1. The number of pole pairs p of the rotor 1 can be grasped as the number of pairs of magnetic pole faces formed on the outer peripheral side surface 11 of the rotor core 10. In the example of FIG. 1, since the number of pole pairs p of the rotor 1 is 2, 6 (= (2 + 1) × 2) magnetic barrier portions 111 are provided.

  A rotating electrical machine can be realized by disposing a stator (not shown) so as to face the outer peripheral side surface 11 through an air gap in the radial direction with respect to the rotor 1. In addition, according to the present rotor 1, for example, when the rotor 1 is rotated by passing a current through a coil of the stator, vibration due to the swing of the rotor 1 can be reduced. Hereinafter, the magnetic flux density resulting from the swinging will be described, and then the reduction of vibration will be specifically described.

<Magnetic flux density due to swing>
Although the rotor 1 ideally rotates around the rotation axis P, in practice, for example, a difference occurs between the center of the rotor 1 and the center of the stator, so that the rotor 1 is A swing around P is also performed in parallel. Here, the rotation operation is a rotation operation of the rotor 1 about the axis P, and the swinging is a revolution operation in which the center of the rotor 1 rotates about the axis P.

The air gap between the rotor 1 and the stator fluctuates due to this swinging. For example, as shown in FIG. 2, an air gap in the case where the center Q1 of the rotor 1 is shifted downward from the center Q2 of the stator will be considered. In FIG. 2, the rotor 1 is shown in a simplified manner, and the surface of the stator that faces the rotor 1 is shown by a broken line. The deviation between the center Q2 of the stator and the center Q1 of the rotor 1 but in practice is about 0.1 mm, it is exaggerated such deviation.

As shown in FIG. 2, the air gap is largest in the upper side, smallest lower side, and the air gap when the position of the center Q2 of the center Q1 of the rotor 1 stator in left-right direction coincides Almost matches.

Next, when the rotor 1 rotates, for example, a change in the air gap at a position passing through the point A located at the top of the paper surface will be considered. Initially, the air gap at point A takes the maximum value. Then, by rotating with a whirling the rotor 1, for example, counter-clockwise, the air gap at the point A decreases. And when rotated 90 degrees rotation angle, as shown in FIG. 3, the air gap at the point A, substantially coincides with the air gap when the center Q2 of the center Q1 of the rotor 1 stator are matched to each other .

The air gap at point A also decreases with subsequent rotation. Then, as shown in FIG. 4, when the air is rotated 180 degrees at the rotation angle, the air gap at the point A takes the minimum value. Subsequent rotation increases the air gap at point A. Then, as shown in FIG. 5 when rotated 270 degrees rotation angle, the air gap at the point A substantially coincides with the air gap when the center Q2 of the stator and the center Q1 of the rotor 1 are matched with each other. The air gap at point A is increased by the subsequent rotation, and the maximum value is again obtained when the rotation angle is rotated 360 degrees.

  As can be understood from the fluctuation of the air gap at the point A, the air gap at the point A has many cosine wave components having a rotation angle of 360 degrees as one cycle.

  In view of the fact that the magnetic resistance increases as the air gap increases, the permeance fluctuates similarly to the fluctuation of the air gap due to the swing of the rotor 1. Therefore, if the fluctuation of the air gap at the point A is grasped by the cosine wave component, the permeance Rm passing through the point A can be expressed by the following equation.

  Rm = 1 + a · cos θ (1)

However, the permeance when the center Q1 of the rotor 1 coincides with the center Q2 of the stator is normalized to 1. Also a is a value resulting from the deviation of the center Q2 of the stator and the center Q1 of the rotor. a increases as the deviation between the center Q1 of the rotor 1 and the center Q2 of the stator increases.

When the center Q1 of the rotor 1 and the center Q2 of the stator coincide with each other, the magnetomotive force B1 resulting from the rotational operation is expressed by the following equation.

  B1 = cos (pθ) (2)

  For simplicity, the phase difference between the permeance Rm and the magnetomotive force B1 is set to zero. The magnetomotive force B1 is grasped by standardizing the amplitude of the magnetic flux density to 1.

  The magnetic flux density B2 flowing between the rotor 1 and the stator at the point A is represented by the product of the magnetomotive force B1 resulting from the rotational operation and the permeance Rm that varies due to the swing.

B2 = Rm · B1
= (1 + a · cos θ) cos (pθ)
= Cos (pθ)
+ A / 2 · {cos (p + 1) θ + cos (p−1) θ} (3)

The cos (pθ) shown on the right side of the equation (3) is the magnetic flux density resulting from the rotation operation. A {cos (p + 1) θ + cos (p−1) θ} shown on the right side of the equation (3) is a magnetic flux density caused by swinging. When the rotor 1 is steadily rotating, the value a is considered to take a constant value without depending on the angle θ because of the symmetry of the rotor and the stator. Due to the rotation, a (p ± 1) -order harmonic component is generated with a cosine wave having a rotation angle of 360 degrees as one period as a fundamental wave.

  Here, it is assumed that the phase difference between the permeance Rm and the magnetic flux density B1 is zero. However, even if this phase difference is calculated as φ, a (p ± 1) -order harmonic component may be generated in the magnetic flux density B2. I can guide.

Further, as shown in the equation (2), the permeance Rm caused by the swinging is expressed by cos θ, but actually has a plurality of harmonic components. Therefore, although the magnetic flux density B2 actually includes an nth-order harmonic component, the main component of fluctuation of the permeance Rm can be expressed by cos θ as shown in the equation (2). p ± 1) It contains more harmonic components than the other harmonic components.

  The p-order harmonic component is generated due to the rotational operation of the rotor 1 and contributes to the torque of the rotating electrical machine and does not cause an increase in vibration. Other harmonic components are components that can cause vibration as a factor of the radial electromagnetic excitation force. In particular, the electromagnetic excitation force whose order is the sum of p and p + 1 (2p + 1) is a relatively large factor that increases vibration. Such an opinion has been experimentally confirmed by the present applicant. The (2p + 1) -th order electromagnetic excitation force is calculated using the p-order harmonic component and the (p + 1) -order harmonic component as factors.

<Reducing vibration>
In the rotor 1 shown in FIG. 1, {(p + 1) × 2} magnetic barrier portions 111 are respectively provided in regions divided by {(p + 1) × 2} equally around the axis P. . Therefore, the magnetic barrier 111 is provided in the vicinity of the position corresponding to the period of the (p + 1) -order harmonic component. Since the magnetic barrier 111 causes an increase in magnetic resistance, the (p + 1) -order harmonic component of the magnetic flux density B2 can be reduced in a well-balanced manner.

  In the illustration of FIG. 1, the magnetic barrier portions 111 are provided at substantially equal intervals in the circumferential direction. Thereby, the magnetic barrier part 111 is provided corresponding to the period of the (p + 1) -order harmonic component. If the position of the magnetic barrier unit 111 coincides with the position corresponding to the peak and valley of the (p + 1) -order harmonic component, the (p + 1) -order harmonic component can be reduced most.

  As described above, since the (p + 1) -order harmonic component can be reduced in a balanced manner, the (2p + 1) -order electromagnetic excitation force generated by the p-order harmonic component and the (p + 1) -order harmonic component can be reduced. The vibration can be efficiently reduced as compared with the reduction of other order harmonic components.

  FIG. 6 shows an example of a fifth-order electromagnetic excitation force with respect to the square of the magnetic flux density B2 (that is, the radial electromagnetic excitation force). In the illustration of FIG. 6, the fifth-order electromagnetic excitation force for the rotor that does not have the magnetic barrier 111 is indicated by a solid line, and the fifth-order electromagnetic excitation force for the rotor 1 of FIG. Has been. As shown in FIG. 6, according to the rotor 1 having the magnetic barrier unit 111, the fifth-order electromagnetic excitation force can be reduced. In the illustration of FIG. 6, the amplitude of the fifth-order electromagnetic excitation force is reduced by about 10%.

  FIG. 7 shows an example of a component (here, a second harmonic component) that contributes to the torque in the magnetic flux density B2. In the illustration of FIG. 7, the magnetic flux density B1 for the rotor that does not have the magnetic barrier 111 is shown by a solid line, and the magnetic flux density B1 for the rotor 1 of FIG. 1 is shown by a broken line. As shown in FIG. 7, according to the rotor 1 having the magnetic barrier 111, the amplitude of the component contributing to the torque is hardly reduced.

  As described above, according to the present rotor 1, the fifth-order electromagnetic excitation force is suppressed while suppressing the reduction in the amplitude of the component contributing to the torque, as compared with the rotor not having the magnetic barrier 111. Can be reduced. The fifth-order electromagnetic excitation force is generated due to the swinging motion of the rotor 1 and becomes a main factor for increasing the vibration. According to the present rotor 1, the fifth-order electromagnetic excitation force can be reduced, which is efficient. Vibration can be reduced. Moreover, since the fall of the amplitude of the component which contributes to a torque is suppressed, reducing a torque, the fall of a torque can be suppressed.

  As described above, the magnetic flux density B2 includes (p ± 1) order harmonic components due to the swing of the rotor 1. In the rotor 1 of FIG. 1, since ((p + 1) × 2) magnetic barrier portions 111 are provided in the rotor core 10, (p + 1) -order harmonic components can be reduced in a balanced manner. On the other hand, by providing ((p−1) × 2) magnetic barrier portions 111 in the rotor core 10, (p−1) -order harmonic components can be reduced in a balanced manner. (P-1) The electromagnetic excitation force in the radial direction is increased also by the next harmonic component, resulting in an increase in vibration. In this case, the (p-1) order harmonic component can be reduced. Vibration can be reduced. In addition, as can be understood from the equation (2), the magnetic flux density B2 includes the (p-1) -order harmonic component having a relatively large amplitude, so that the vibration can be efficiently reduced by reducing this. However, as described above, since the (2p + 1) -th order electromagnetic excitation force greatly affects the vibration, the vibration reduction effect is low as compared with the case where the (p + 1) -order harmonic component is reduced.

  Further, (((p + 1) × 2) + ((p−1) × 2)) magnetic barrier portions 111 are provided in the rotor core 10 according to the (p ± 1) -order harmonic component. It may be. In this case, the (p ± 1) order harmonic component can be reduced, and hence vibration can be further reduced. Note that some of the magnetic barrier portions 111 corresponding to the (p + 1) -order harmonic component and some of the magnetic barrier portions 111 corresponding to the (p-1) -order harmonic component are provided at the same position in the circumferential direction. In such a case, for each of these, one magnetic barrier 111 may be provided at that position.

  In the following, other modes are exemplified as the magnetic barrier unit 111, but the number and the position in the circumferential direction of the magnetic barrier unit 111 are the same as those in the first embodiment, and thus detailed description thereof is omitted.

Second embodiment.
The rotor 1 shown in FIG. 8 is different from the rotor 1 shown in FIG.

  The magnetic barrier 111 is shown as a hole 113. Since the hole 113 is filled with a fluid such as air or a refrigerant, the hole 113 can function as a magnetic barrier. The hole 113 is provided between the outer peripheral side surface 11 of the rotor core 10 and the permanent magnet 20 (more specifically, between the ring passing through the permanent magnet 20 and the outer peripheral side surface 11). The magnetic barrier 111 is not limited to the hole 113, and the hole 113 may be filled with a nonmagnetic material. If the nonmagnetic material is filled, the strength of the rotor 1 can be improved.

In the illustration of FIG. 8 , the magnetic barrier portion 111 (hole 113) has a long shape when viewed in the axial direction, and is arranged so that its long side is in the circumferential direction. If the gap 121 is formed in the rotor core 10, the magnetic barrier 111 may be provided avoiding the gap 121 as shown in FIG. 8 .

  Even with such a magnetic barrier 111, it is possible to reduce the vibration caused by the swing of the rotor 1 as in the first embodiment. Further, since the magnetic barrier 111 is provided between the outer peripheral side surface 11 and the permanent magnet 20, it is not necessary to form a groove on the outer peripheral side surface 11. Therefore, the air gap can be measured at any position in the circumferential direction of the outer peripheral side surface 11. In other words, the magnetic barrier 111 does not hinder measurement of the air gap. Therefore, the workability of air gap measurement can be improved.

The magnetic barrier portion 111 preferably has a radial position closer to the outer peripheral side surface 11. FIG. 9 shows the relationship between the distance from the center Q2 of the rotor 1 to the magnetic barrier 111 and the ratio of the third harmonic component to the component (second harmonic component) contributing to the torque of the magnetic flux density B2. Yes. FIG. 10 shows the result for the rotor 1 in which the radius of the outer peripheral side surface 11 with respect to the center Q2 is 29.8 mm. In the graph, data in which the distance between the center Q2 and the magnetic barrier 111 is 29.8 mm indicates a case where the magnetic barrier 111 is not provided in the rotor core 10.

As shown in FIG. 9 , the magnetic barrier portion 111 can reduce the third-order harmonic component as it is closer to the outer peripheral side surface 11. Then, when the magnetic barrier portion 111 is at a position where the magnetic barrier portion 111 is in contact with the circumscribed circle R1 of the permanent magnet 20 from the outer peripheral side (the distance between the center Q2 and the magnetic barrier portion 111 is the radius of the circumscribed circle R1), The second harmonic component coincides with that when the magnetic barrier 111 is not provided. Therefore, the magnetic barrier portion 111 is required to be positioned between the circumscribed circle R1 of the permanent magnet 20 and the outer peripheral side surface 11.

Note that the air gap 121 may be grasped as the magnetic barrier 111 as in the first embodiment. In the example of FIG. 8 , for example, the air gap 121 may be grasped as the magnetic barrier portion 111 without providing the four holes 113 close to the air gap 121.

Third embodiment.
The rotor 1 shown in FIG. 10 is different in the magnetic barrier 111 from the rotor 1 shown in FIG.

  The rotor core 10 is composed of a plurality of electromagnetic steel plates stacked in the axial direction. The plurality of electromagnetic steel plates are fixed to each other by the projections and recesses provided in each of them being fitted in the axial direction. Such irregularities are provided by pressing a predetermined member into the magnetic steel sheet along the axial direction to form a concave portion on one surface and a convex portion on the other surface at the same position. Thus, the irregularities are formed by deformation of the electrical steel sheet. Therefore, the magnetic properties of the unevenness deteriorate. Moreover, since the convex part of one magnetic steel sheet and the concave part which contacts this with an axial direction are not completely continuous, a magnetic characteristic deteriorates also in this boundary.

In consideration of the deterioration of the magnetic characteristics, the rotor 1 shown in FIG. 10 employs the unevenness 114 that fixes the electromagnetic steel plates to each other as the magnetic barrier portion 111. The unevenness 114 is provided as described in the second embodiment for the position in the radial direction as described in the first embodiment for the position in the circumferential direction. However, when the capability of the unevenness 114 as a magnetic barrier is smaller than the capability of the hole 113 as a magnetic barrier, it is better to be positioned closer to the outer peripheral side surface 11 than the circumscribed circle R1 of the permanent magnet 20.

  Thereby, the vibration of the rotor 1 can be reduced, and the workability of the air gap measurement can be improved as in the second embodiment. In addition, since the magnetic barrier unit 111 exhibits a function of fixing a plurality of electromagnetic steel plates and a function of a magnetic barrier for reducing vibrations, a dedicated fixing unit and a magnetic barrier unit that exhibit each function are provided. Compared with this, the manufacturing cost can be reduced.

Note that the air gap 121 may be grasped as the magnetic barrier 111 as in the first embodiment. In the example of FIG. 10 , the air gap 121 may be grasped as the magnetic barrier unit 111 without providing the four irregularities 114 close to the air gap 121. However, it is desirable to provide a certain number of irregularities 114 for fixing the electromagnetic steel sheets because the greater the number of the unevennesses 114, the greater the force for fixing the electromagnetic steel sheets.

Fourth embodiment.
The rotor 1 described in the first to third embodiments is used for a motor for a hermetic compressor, for example. FIG. 11 is a longitudinal sectional view of a compressor to which the motor is applied. The compressor shown in FIG. 11 is a high-pressure dome type rotary compressor, and for example, carbon dioxide is adopted as the refrigerant. In FIG. 11 , an accumulator K100 is also shown.

  This compressor includes a hermetic container K1, a compression mechanism K2, and a motor K3. The compression mechanism K2 is disposed in the sealed container K1. The motor K3 is disposed in the sealed container K1 and above the compression mechanism K2. Here, the upper side means the upper side along the central axis of the sealed container K1, regardless of whether the central axis of the sealed container K1 is inclined with respect to the horizontal plane.

  The motor K3 drives the compression mechanism part K2 via the rotating shaft K4. The motor K3 includes a rotor 1 and a stator 3.

  A suction pipe K11 is connected to the lower side of the sealed container K1, and a discharge pipe K12 is connected to the upper side of the sealed container K1. Refrigerant gas (not shown) from the accumulator K100 is supplied to the sealed container K1 via the suction pipe K11 and guided to the suction side of the compression mechanism K2. This rotary compressor is a vertical type, and has an oil sump at least under the motor K3.

  The stator 3 is disposed on the outer peripheral side of the rotor 1 with respect to the rotary shaft K4, and is fixed to the sealed container K1.

  The compression mechanism K2 includes a cylindrical main body K20, an upper end plate K8, and a lower end plate K9. The upper end plate K8 and the lower end plate K9 are respectively attached to the upper and lower open ends of the main body K20. The rotation shaft K4 passes through the upper end plate K8 and the lower end plate K9, and is inserted into the main body K20. The rotary shaft K4 is rotatably supported by a bearing K21 provided on the upper end plate K8 and a bearing K22 provided on the lower end plate K9.

  The rotation shaft K4 is provided with a crank pin K5 in the main body K20. The piston K6 is fitted to the crank pin K5 and driven. A compression chamber K7 is formed between the piston K6 and the corresponding cylinder. The piston K6 rotates in an eccentric state or revolves to change the volume of the compression chamber K7.

  Next, the operation of the rotary compressor will be described. Refrigerant gas is supplied from the accumulator K100 to the compression chamber K7 via the suction pipe K11. The compression mechanism K2 is driven by the motor K3, and the refrigerant gas is compressed. The compressed refrigerant gas is transported together with refrigerating machine oil (not shown) from the compression mechanism K2 to the upper side of the compression mechanism K2 via the discharge hole K23, and further from the discharge pipe K12 to the sealed container K1 via the motor K3. Is discharged to the outside.

  The refrigerant gas moves upward in the motor K3 together with the refrigerating machine oil. The refrigerant gas is guided to the upper side of the motor K3, but the refrigerating machine oil moves toward the inner wall of the sealed container K1 by the centrifugal force of the rotor 1. The refrigeration oil is liquefied by adhering to the inner wall of the sealed container K1 in the form of fine particles, and then returns to the upstream side of the flow of the refrigerant gas of the motor K3 by the action of gravity.

  In such a hermetic compressor, by employing the first to third rotors 1 as the rotor 1 of the motor K3, the vibration of the rotor 1 and hence the vibration of the hermetic compressor can be reduced.

DESCRIPTION OF SYMBOLS 1 Rotor 10 Rotor core 20 Permanent magnet 111 Magnetic barrier part 112 Groove part 113 Hole 114 Concavity and convexity 121 Space | gap

Claims (5)

A permanent magnet (20) arranged annularly around a predetermined axis (P);
Magnetic poles having different polarities alternately around the axis by the permanent magnet are provided in 2N (N is a natural number) magnetic pole surfaces (11) that are presented in a radial direction around the axis, and the permanent magnet On the other hand, the rotor core (10) is provided on the magnetic pole face side, and has at least one magnetic barrier portion (111) in each of the regions ((N + 1) × 2) equally divided by the angle around the axis. ) and equipped with a,
The ((N + 1) × 2) magnetic barrier portions respectively present in the region are provided at equal intervals in the circumferential direction around the axis (P),
The magnetic barrier portion is a rotor that is different from air gaps (121) provided at both ends of the permanent magnet in the circumferential direction in the circumferential direction . The rotor according to claim 1, wherein the magnetic barrier portion (111) is a groove portion (112) provided in the magnetic pole surface . The rotor according to claim 1, wherein the magnetic barrier portion (111) is a non-magnetic body (113) provided between the permanent magnet and the magnetic pole surface . The rotor core is
A plurality of electrical steel sheets laminated in a direction along the axis (P)
Further comprising
At least a plurality of the plurality of electromagnetic steel plates are fitted with each other and provided with unevenness (114) for fixing in the direction along the axis, and the unevenness functions as the magnetic barrier portion (111). The rotor according to claim 1 . The rotation according to claim 3 or 4 , wherein the magnetic barrier portion (111) is provided on a side opposite to the axis (P) with respect to a circle (R1) having the largest diameter passing through the permanent magnet (20). Child.

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