JP2014064428A - Rotor and rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve strength of a rotor against centrifugal force and prevent an increase in eddy current loss of a permanent magnet due to a decrease in shielding effectiveness in a protective ring.SOLUTION: A permanent magnet (101) is made up of n cylindrical split magnets (111, 111, 111). A protective ring (102) is made up of n cylindrical split rings (112, 112, 112). The n split rings (112, 112, 112) are provided on respective outer circumferences of the n split magnets (111, 111, 111) in such a manner that (n-1) second air gaps (S112, S112) between the n split rings (112, 112, 112) communicate with (n-1) first air gaps (S111, S111) between the n split magnets (111, 111, 111), respectively.

Description

  The present invention relates to a rotating electric machine, and more particularly to a rotor structure.

  Conventionally, in a rotating electric machine such as an electric motor (for example, a surface magnet type motor) or a generator, a retaining ring is provided on the outer periphery of the permanent magnet in order to prevent the permanent magnet from scattering due to the centrifugal force accompanying the rotation of the rotor. Is provided. When the retaining ring is provided in this way, the temperature of the retaining ring rises due to eddy current loss generated in the retaining ring during the rotational operation of the rotor, and as a result, the permanent magnet provided on the inner periphery of the retaining ring is reduced. There is a possibility that the magnetic strength will deteriorate. Therefore, in the rotor of Patent Document 1, the temperature of the permanent magnet is increased by eddy currents by alternately laminating a plurality of permanent magnets with a magnet breakage prevention ring and a plurality of insulating materials along the rotational axis direction. Is suppressed.

JP 2004-180349 A

  However, in the rotor of Patent Document 1, since the retaining ring is not provided on the outer periphery of the insulating material, the insulating material may be scattered by the centrifugal force during the rotation of the rotor. For this reason, it is difficult to improve the strength of the rotor against centrifugal force.

  If the rotor is configured by removing the insulating material as described above from the rotor of Patent Document 1 and laminating a plurality of split rings (magnet breakage prevention rings) and a plurality of split magnets (permanent magnets) in the axial direction, When there is a dimensional error in the axial length of the split ring and the split magnet, the boundary portion between the split rings is not the boundary portion between the split magnets (for example, the central portion of the outer peripheral surface of the split magnet) There is a risk of overlapping. In this case, since the shielding effect by the eddy current (characteristics that hinder the transmission of the harmonic magnetic flux) is reduced at the boundary portion between the split rings, the split magnets are formed at the inner periphery of the boundary portion between the split rings. Eddy current loss will increase.

  Accordingly, an object of the present invention is to provide a rotor capable of improving the strength against centrifugal force of the rotor and suppressing an increase in eddy current loss of the permanent magnet due to a decrease in the shielding effect in the retaining ring.

  The first invention includes a rotor core (100), a cylindrical permanent magnet (101) provided on the outer periphery of the rotor core (100), and a cylindrical holding ring provided on the outer periphery of the permanent magnet (101). (102), and the permanent magnet (101) is divided into n cylindrical sections arranged in parallel in the axial direction of the rotor core (100) with the space between them being separated by a first gap (S111). The holding ring (102) is composed of a magnet (111), and each of the holding rings (102) is separated by a second gap (S112), and n cylindrical shapes arranged in parallel in the axial direction of the rotor core (100). The divided ring (112) includes the n divided rings (112) and the n divided second rings (S112) between the n divided rings (112). The n pieces so as to communicate with (n−1) first gaps (S111) between the divided magnets (111) The rotor is provided on the outer periphery of each of the divided magnets (111).

  In the first invention, the eddy current path in the retaining ring (102) can be divided by the (n-1) second gaps (S112), so the eddy current loss of the retaining ring (102) can be reduced. Can be reduced. Furthermore, the eddy current path in the permanent magnet (101) can be divided by (n-1) first gaps (S111), and (n-1) second second of the retaining ring (102). The n divided magnets (111) and the n divided rings (112) are connected so that the air gap (S112) communicates with the (n−1) first air gaps (S111) of the permanent magnet (101), respectively. By arranging, the portion of the retaining ring (102) where the shielding effect is reduced can be arranged in the portion of the permanent magnet (101) where the eddy current path is divided. Further, it is not necessary to provide an insulating material (a member not held by the split ring (112)) between the n split magnets (111) held by the split ring (112).

  According to a second aspect, in the first aspect, the axial length (L2) of the split ring (112) is the axial length of the split magnet (111) corresponding to the split ring (112) ( The rotor is characterized by being different from L1).

  In the second aspect of the invention, the split magnet is determined by the difference between the axial length (L2) of the split ring (112) and the axial length (L1) of the split magnet (111) corresponding to the split ring (112). Dimensional errors in the axial lengths of (111) and split ring (112) can be tolerated. That is, it is possible to suppress the displacement of the first gap (S111) and the second gap (S112) due to the dimensional error in the axial length.

  According to a third invention, in the second invention, the first gap (S111) in which the axial length (D2) of the second gap (S112) corresponds to the second gap (S112). The axial length (L2) of the split ring (112) is longer than the axial length (D1) of the split magnet (111) corresponding to the split ring (112). The rotor is characterized in that it is shorter than.

  In the third invention, the first gap of the permanent magnet (101) in which the axial length (D2) of the second gap (S112) of the retaining ring (102) corresponds to the second gap (S112). The n divided magnets (111) and the n divided rings (112) are arranged so as to be longer than the axial length (D1) of (S111).

  According to a fourth invention, in any one of the first to third inventions, further comprising a cylindrical reinforcing ring (103) provided on an outer periphery of the holding ring (102). Rotor.

  In the fourth aspect of the present invention, scattering of the retaining ring (102) due to centrifugal force during rotation of the rotor (11) can be prevented.

  5th invention is equipped with the rotor (11) which is any one of the said 1st-4th invention, and the stator (12) by which the said rotor (11) is penetrated, It is characterized by the above-mentioned. It is a rotating electrical machine.

  In the fifth aspect of the invention, the strength of the rotor (11) against the centrifugal force can be improved, and an increase in eddy current loss of the permanent magnet (101) due to a decrease in the shielding effect in the retaining ring (102) can be suppressed.

  According to the first invention, the portion of the retaining ring (102) where the shielding effect is reduced can be disposed in the portion of the permanent magnet (101) where the eddy current path is divided. An increase in eddy current loss of the permanent magnet (101) due to a decrease in the shielding effect in (102) can be suppressed. Further, since it is not necessary to provide an insulating material between the n divided magnets (111) held by the divided ring (112), the strength of the rotor (11) against the centrifugal force can be improved.

  According to the second invention, it is possible to suppress the displacement of the first gap (S111) and the second gap (S112) due to the dimensional error of the axial length, so that the (n) of the retaining ring (102) -1) The rotor (11) in which the second air gaps (S112) communicate with the (n-1) first air gaps (S111) of the permanent magnet (101) can be easily manufactured. it can.

  According to the third invention, the axial length (D2) of the second gap (S112) of the retaining ring (102) is the first length of the permanent magnet (101) corresponding to the second gap (S112). Since it is longer than the axial length (D1) of the air gap (S111), the eddy current loss of the retaining ring (102) can be reduced while suppressing the deterioration of the magnetic performance of the permanent magnet (101). .

  According to the fourth invention, since the scattering of the retaining ring (102) due to the centrifugal force during rotation of the rotor (11) can be prevented, the strength of the rotor (11) against the centrifugal force can be further improved.

  According to the fifth invention, the strength of the rotor (11) against the centrifugal force can be improved, and an increase in eddy current loss of the permanent magnet (101) due to a decrease in the shielding effect in the retaining ring (102) can be suppressed. Therefore, it is possible to suppress the deterioration of the magnetic characteristics of the rotating electrical machine (10).

The cross-sectional view for demonstrating the structural example of a rotary electric machine. The longitudinal cross-sectional view for demonstrating the structural example of a rotary electric machine. The enlarged view for demonstrating the principal part of a rotor. The longitudinal cross-sectional view for demonstrating the modification of a rotor.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

[Rotating electrical machine]
1 and 2 show a transverse section and a longitudinal section, respectively, of a rotating electrical machine (10) according to an embodiment of the present invention. For example, the rotary electric machine (10) is used as an electric motor for driving a compressor (not shown) of an air conditioner. In this example, the rotating electrical machine (10) constitutes a surface magnet type motor (SPM motor). The rotating electric machine (10) includes a rotor (11) and a cylindrical stator (12) through which the rotor (11) is inserted, and is accommodated in a casing (30) (for example, a casing of a compressor). . The rotor (11) includes a rotor core (100), a permanent magnet (101), and a holding ring (102). The rotor core (100) is fixed to the drive shaft (20).

  In the following description, the “axial direction” refers to the direction of the axis of the drive shaft (20) (that is, the center of the rotation axis of the rotor core (100)), and the “radial direction” refers to the drive shaft ( 20) is the direction orthogonal to the axial direction, and the “outer peripheral side” is the side farther from the axis of the drive shaft (20), and the “inner peripheral side” is the drive shaft (20 ) Is closer to the axis. The “longitudinal section” is a section along the axial direction, and the “transverse section” is a section orthogonal to the axial direction.

<Stator>
The stator (12) includes a cylindrical stator core (201) and a coil (202).

《Stator core》
The stator core (201) is a laminated core formed by punching an electromagnetic steel plate by press working to produce a laminated plate, and laminating a plurality of laminated plates in the axial direction. The stator core (201) includes a back yoke portion (211), a plurality of teeth portions (212, 212,...), And a plurality of flange portions (213, 213,...).

  The back yoke portion (211) is formed on the outer peripheral portion of the stator core (201) and is formed in an annular shape. The outer periphery of the back yoke portion (211) is fixed to the inner surface of the casing (30).

  The teeth part (212) is formed in a rectangular parallelepiped shape extending in the radial direction from the inner peripheral surface of the back yoke part (211). Between the teeth portions (212, 212,...), Coil slots (S200, S200,...) For accommodating the coils (202) are formed.

  The brim portion (213) is continuously formed on the inner peripheral side of the teeth portion (212). The brim portion (213) is configured to have a larger width (length in the circumferential direction) than the tooth portion (212), and the inner circumferential surface is formed into a cylindrical surface. The cylindrical surface of the flange (213) faces the outer peripheral surface (cylindrical surface) of the rotor (11) with a predetermined distance (air gap (G)).

"coil"
The coil (202) is wound around the tooth portion (212). That is, the wound coil (202) is accommodated in the coil slot (S200). Thereby, an electromagnet is formed in each of the tooth portions (212, 212,...).

<Rotor>
The rotor (11) includes a rotor core (100), a permanent magnet (101), and a holding ring (102).

<Rotor core>
The rotor core (100) is formed in a cylindrical shape. A shaft hole (110) is formed at the center of the rotor core (100). The drive shaft (20) is fixed to the shaft hole (110) by press fitting or the like.

"permanent magnet"
The permanent magnet (101) is formed in a cylindrical shape so as to cover the outer periphery of the rotor core (100). For example, the permanent magnet (101) is bonded to the outer periphery of the rotor core (100). The permanent magnet (101) is composed of n (n is a natural number, in this example, n = 3) divided magnets (111, 111, 111). The split magnet (111) is formed in a cylindrical shape. Further, the divided magnets (111, 111, 111) are arranged in parallel in the axial direction with a gap (S111) (first gap) therebetween. For example, the split magnet (111) is configured by a magnet using a rare earth metal (for example, a neodymium iron boron-based magnet) or a ferrite magnet. In this example, each of the divided magnets (111, 111, 111) is configured by assembling four arc-shaped magnets into a cylindrical shape. The split magnet (111) may be constituted by a single anisotropic ring magnet formed in a cylindrical shape.

《Retaining ring》
The retaining ring (102) is formed in a cylindrical shape so as to cover the outer periphery of the permanent magnet (101). For example, the retaining ring (102) is shrink fitted on the outer periphery of the permanent magnet (101). The holding ring (102) is composed of n (three in this example) split rings (112, 112, 112). That is, the number of divisions of the division ring (112) is the same as the number of divisions of the division magnet (111). The split ring (112) is formed in a cylindrical shape. Further, the split rings (112, 112, 112) are arranged in parallel in the axial direction with a gap (S112) (second gap) therebetween. More specifically, the split ring (112, 112, 112) has (n−1) (two in this example) gaps (S112, S112) of the retaining ring (102) and (n−) of the permanent magnet (101). 1) It is provided on the outer periphery of each of the divided magnets (111, 111, 111) so as to communicate with each of the gaps (S111, S111). For example, the split ring (112) is made of a nonmagnetic material.

<Main parts of the rotor>
Next, with reference to FIG. 3, the principal part of a rotor (11) is demonstrated. The axial length (L2) of the split ring (112) is equal to the split magnet (111) corresponding to the split ring (112) (more specifically, the split provided on the inner periphery of the split ring (112)). It is configured to be different from the axial length (L1) of the magnet (111). In this example, the axial length (L2) of the split ring (112) is shorter than the axial length (L1) of the split magnet (111). Further, the axial length (D2) of the gap (S112) of the retaining ring (102) is equal to the gap (S111) of the permanent magnet (101) corresponding to the gap (S112) (more specifically, the gap ( This is different from the axial length (D1) of the air gap (S111) communicating with S112). In this example, the axial length (D2) of the gap (S112) is longer than the axial length (D1) of the gap (S111).

  Axial length of the permanent magnet (101) (that is, the sum of the axial length (L1, L1, L1) of the split magnet (111, 111, 111) and the axial length (D1, D1) of the air gap (S111, S111)) Is the same as the axial length (L0) of the rotor core (100). Also, the axial length of the retaining ring (102) (that is, the axial length (L2, L2, L2) of the split ring (112, 112, 112) and the axial length (D2, D2) of the gap (S112, S112) (Total) is also the same as the axial length (L0) of the rotor core (100).

<Eddy current loss of retaining ring>
As the eddy current loss of the retaining ring (102) increases, the temperature rise amount of the retaining ring (102) increases. For example, as the rotational speed of the rotor (11) increases, the eddy current loss of the holding ring (102) that occurs during the rotation of the rotor (11) increases. As the amount of temperature rise of the retaining ring (102) increases, the amount of heat transferred from the retaining ring (102) to the permanent magnet (101) increases, so the temperature of the permanent magnet (101) increases and the magnet performance increases. Since the holding force is reduced, the demagnetization resistance against a reverse magnetic field by the stator (12) is deteriorated. Thus, as the eddy current loss of the retaining ring (102) increases, the magnetic characteristics of the rotating electrical machine (10) deteriorate.

<Eddy current loss of permanent magnet>
On the other hand, the smaller the eddy current in the retaining ring (102), the smaller the eddy current loss in the retaining ring (102). However, the retaining effect on the retaining ring (102) is to prevent transmission of harmonic magnetic flux. Characteristic) is reduced, and eddy currents generated in the permanent magnet (101) arranged on the inner periphery of the retaining ring (102) are increased. Moreover, since the temperature of the permanent magnet (101) increases as the eddy current loss of the permanent magnet (101) increases, the demagnetization resistance of the permanent magnet (101) deteriorates. Thus, as the eddy current loss of the permanent magnet (101) increases, the magnetic characteristics of the rotating electrical machine (10) deteriorate.

<effect>
In the rotating electrical machine (10) according to this embodiment, since the split rings (112, 112, 112) constituting the holding ring (102) are separated by the air gaps (S112, S112), eddy currents in the holding ring (102) The path can be divided by the gap (S112, S112). Thereby, the eddy current loss of the holding ring (102) can be reduced. Furthermore, since the split magnets (111, 111, 111) that make up the permanent magnet (101) are separated by air gaps (S111, S111), the eddy current path in the permanent magnet (101) is separated by the air gaps (S111, S111). can do. By arranging the split magnets (111, 111) and the split rings (112, 112) so that the gaps (S112, S112) of the retaining ring (102) communicate with the gaps (S111, S111) of the permanent magnet (101), respectively. In the retaining ring (102), the portion where the shielding effect (shielding effect due to the eddy current of the retaining ring (102)) is reduced is the portion where the path of the eddy current is divided in the permanent magnet (101) (ie, the eddy current). It is possible to arrange (superimpose) on a portion where current is difficult to generate. Thereby, the increase in the eddy current loss of the permanent magnet (101) by the fall of the shielding effect in a holding ring (102) can be suppressed.

  Further, since it is not necessary to provide an insulating material (member not held by the split ring (112, 112, 112)) between the split magnets (111, 111, 111) held by the split ring (112, 112, 112), the rotor (11) with respect to the centrifugal force Strength can be improved.

  As described above, it is possible to improve the strength against the centrifugal force of the rotor (11) and to suppress an increase in eddy current loss of the permanent magnet (101) due to a decrease in the shielding effect in the retaining ring (102). Degradation of the magnetic properties of the electric machine (10) can be suppressed.

  Further, the split magnet (111, 111, 111) and the split ring (112) are divided so that the axial length (L2) of the split ring (112) is different from the axial length (L1) of the split magnet (111) corresponding to the split ring (112). Since the ring (112, 112, 112) is configured, the split magnet (111) and the split magnet are divided by the difference between the axial length (L1) of the split magnet (111) and the axial length (L2) of the split ring (112). A dimensional error in the axial length of the ring (112) can be tolerated. That is, it is possible to suppress displacement of the gaps (S111, S111) of the permanent magnet (101) and the gaps (S112, S112) of the retaining ring (102) due to the dimensional error of the axial length. Therefore, the split magnets (111, 111, 111) and the split rings (112, 112, 112) are easily arranged so that the gaps (S112, S112) of the retaining ring (102) communicate with the gaps (S111, S111) of the permanent magnet (101), respectively. be able to. Thereby, the rotor (11) in which the gaps (S112, S112) of the retaining ring (102) communicate with the gaps (S111, S111) of the permanent magnet (101) can be easily manufactured.

  Note that the eddy current loss of the retaining ring (102) decreases as the axial length (D2, D2) of the gap (S112, S112) of the retaining ring (102) increases. On the other hand, the shorter the axial length (D1, D1) of the gaps (S111, S111) of the permanent magnet (101), the smaller the deterioration of the magnetic performance of the permanent magnet (101). Therefore, the split magnets (111, 111, 111) are configured such that the axial length (L2) of the split ring (112) is shorter than the axial length (L1) of the split magnet (111) corresponding to the split ring (112). And the split ring (112, 112, 112), and the axial length (D2) of the gap (S112) of the retaining ring (102) is the axial direction of the gap (S111) of the permanent magnet (101) corresponding to the gap (S112). By arranging the split magnets (111, 111, 111) and the split rings (112, 112, 112) so as to be longer than the length (D1), the deterioration of the magnetic performance of the permanent magnet (101) is suppressed, and the retaining ring (102) Eddy current loss can be reduced.

[Modification of rotor]
As shown in FIG. 4, the rotor (11) may include a reinforcing ring (103) formed in a cylindrical shape in addition to the configuration shown in FIGS. The reinforcing ring (103) is provided on the outer periphery of the holding ring (12). For example, the reinforcing ring (103) is made of carbon fiber reinforced plastic (CFRP). In this example, the axial length of the reinforcing ring (103) is the same as the axial length (L0) of the rotor core (100).

  By configuring as described above, scattering of the retaining ring (102) due to centrifugal force during rotation of the rotor (11) can be prevented, so that the strength of the rotor (11) against centrifugal force can be further improved. . Further, since the thickness (radial width) of the retaining ring (102) can be reduced while maintaining the strength of the rotor (11) against centrifugal force, the weight of the rotor (11) can be reduced.

[Modification of split ring and split magnet]
The split magnet (111, 111, 111) has a length (L2) in the axial direction of the split ring (112) that is longer than the length (L1) in the axial direction of the split magnet (111) corresponding to the split ring (112). And the split ring (112, 112, 112), and the axial length (D2) of the gap (S112) of the retaining ring (102) is the axial direction of the gap (S111) of the permanent magnet (101) corresponding to the gap (S112). The split magnets (111, 111, 111) and the split rings (112, 112, 112) may be arranged so as to be shorter than the length (D1). Even in this configuration, the gaps (S111, S111) of the permanent magnet (101) and the gaps (S112) of the retaining ring (102) due to dimensional errors in the axial lengths of the split magnets (111, 111, 111) and the split rings (112, 112, 112). , S112), the rotor (11) in which the gaps (S112, S112) of the retaining ring (102) communicate with the gaps (S111, S111) of the permanent magnet (101) can be suppressed. It can be manufactured easily.

[Modification of rotor core]
Further, the rotor core (100) may be formed in a polygonal column shape (for example, a quadrangular column shape) instead of a cylindrical shape. In this case, the split magnet (111) is configured by assembling a plurality of semi-cylindrical magnets (for example, four semi-cylindrical magnets when the rotor core (100) is formed in a quadrangular prism shape) into a cylindrical shape. May be.

[Other Embodiments]
In the above description, the case where the rotating electric machine (10) constitutes an electric motor has been described as an example, but the rotating electric machine (10) may constitute a generator.

  Moreover, you may implement combining the above embodiment suitably. The above embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its use.

  As described above, the rotating electric machine described above is useful as an electric motor for driving a compressor of an air conditioner.

DESCRIPTION OF SYMBOLS 10 Rotating electric machine 20 Drive shaft 30 Casing 11 Rotor 12 Stator 100 Rotor core 101 Permanent magnet 102 Holding ring 103 Reinforcement ring 111 Split magnet S111 Space | gap (1st space | gap)
112 Split ring S112 gap (second gap)
201 Stator core 202 Coil 211 Back yoke part 212 Teeth part 213 Head part

Claims (5)

Rotor core (100),
A cylindrical permanent magnet (101) provided on the outer periphery of the rotor core (100);
A cylindrical retaining ring (102) provided on the outer periphery of the permanent magnet (101),
The permanent magnet (101) is composed of n cylindrical divided magnets (111) arranged in parallel in the axial direction of the rotor core (100) with a space between them being separated by a first gap (S111). ,
The holding ring (102) is constituted by n cylindrical dividing rings (112) arranged in parallel in the axial direction of the rotor core (100) with a space between them being separated by a second gap (S112). ,
The n number of split rings (112) include (n-1) second gaps (S112) between the n number of split rings (112) between the n number of split magnets (111). A rotor characterized by being provided on the outer periphery of each of the n divided magnets (111) so as to communicate with the (n-1) first gaps (S111). In claim 1,
A rotor characterized in that an axial length (L2) of the split ring (112) is different from an axial length (L1) of the split magnet (111) corresponding to the split ring (112). In claim 2,
The axial length (D2) of the second gap (S112) is longer than the axial length (D1) of the first gap (S111) corresponding to the second gap (S112).
An axial length (L2) of the split ring (112) is shorter than an axial length (L1) of the split magnet (111) corresponding to the split ring (112). Rotor. In any one of Claims 1-3,
The rotor further comprising a cylindrical reinforcing ring (103) provided on the outer periphery of the holding ring (102). The rotor (11) according to any one of claims 1 to 4,
A rotary electric machine comprising a stator (12) through which the rotor (11) is inserted.

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