JP2013198303A - Rotor structure of permanent magnet type rotary machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotor structure of a permanent magnet type rotary machine that prevents leakage magnetic flux and increase magnetic flux density in a gap even when a rotor core is structured in one body and when a permanent magnet having low remanent flux density is used as a permanent magnet generating main magnetic flux.SOLUTION: A rotor 1 comprises a rotor core 11 in which a shaft 2 is fitted, a plurality of ferrite magnets 12 embedded radially at positions part from the shaft 2 of the rotor core 11, and a plurality of neodymium magnets 13 embedded between the shaft 2 of the rotor core 11 and the ferrite magnets 12. The rotor core 11 is provided with a connection portion 115 connecting rotor core pieces 114, and the neodymium magnets 13 are arranged having the same magnetization direction with the ferrite magnets 12 arranged opposite in radial directions, and also preventing magnetic flux of the ferrite magnets 12 from short-circuiting between the rotor core pieces 114 adjacent in a peripheral direction.

Description

  The present invention relates to a rotor structure of a permanent magnet type rotating machine, and more particularly to a rotor structure of a permanent magnet type rotating machine in which permanent magnets are arranged radially with respect to a rotating shaft.

  2. Description of the Related Art Conventionally, a rotor structure of a permanent magnet type rotating machine is known in which permanent magnets are arranged radially with respect to a rotating shaft to increase the magnetic flux density in the gap of the permanent magnet type rotating machine. As such a rotor structure, a rotor core that is completely integrated by providing a through hole for embedding a permanent magnet in the rotor core (for example, see Patent Documents 1 and 2 below), Two types of structures are known in which the rotor core is separated for each magnetic pole (see, for example, Patent Documents 3 and 4 below).

JP 2000-152534 A JP 2010-4722 A JP 2009-77469 A JP 2011-78298 A

  Here, in the rotor structure in which the above-described conventional rotor core is completely integrated, the rotor core is positioned on both sides in the circumferential direction of the through hole on the radially outer side or radially inner side of the through hole. There will be a connecting portion connecting the rotor cores.

  Even if there is a connecting part, when using a magnet with a high residual magnetic flux density, such as a neodymium magnet, as the permanent magnet that generates the main magnetic flux, the connecting part can be magnetically saturated, so that the leakage flux can be suppressed. A rotating machine having a high magnetic flux density can be obtained.

  However, when the permanent magnet that generates the main magnetic flux is a permanent magnet having a low residual magnetic flux density such as a ferrite magnet, the connecting portion is not magnetically saturated, and the electrical characteristics deteriorate due to a short circuit between the N pole and the S pole of the magnetic flux. There is a risk that.

  Here, if the radial width of the connecting portion is made as small as possible, the magnetic resistance at that portion increases, and even with a magnet having a low residual magnetic flux density, the connecting portion can be magnetically saturated. There arises a problem that the strength of the core is insufficient.

  Further, in the rotor structure in which the above-described conventional rotor core is separated for each magnetic pole, the shaft, the rotor core, and the permanent magnet are separated by structurally separating the above-described connecting portion and providing a non-magnetic ring. By adopting a structure that integrally fixes the rotor core, the rotor core can be separated for each magnetic pole.

  If the rotor core is separated for each magnetic pole in this way, even with a permanent magnet having a low residual magnetic flux density such as a ferrite magnet, the magnetic flux is prevented from being short-circuited between the N pole and the S pole, and the main magnetic flux amount is increased. A rotor structure that can be obtained can be obtained.

  However, when the rotor core is separated, there is a problem that many members and man-hours are required to assemble the separated core with the shaft with high accuracy. Further, as in Patent Document 3, when a rotor is formed by integrating a plurality of separated cores with a shaft and permanent magnets with a resin, the rotor is fixed with a resin so as to cover the outer peripheral surface of the rotor core. As a result, there is a problem that the gap surface is enlarged and the electrical characteristics may be deteriorated.

  For this reason, the present invention prevents leakage magnetic flux even when the rotor core has an integral structure and a permanent magnet having a low residual magnetic flux density is used as the permanent magnet for generating the main magnetic flux. And it aims at providing the rotor structure of the permanent-magnet-type rotary machine which can enlarge the magnetic flux density in a gap.

  The rotor structure of the permanent magnet type rotating machine according to the first invention for solving the above-mentioned problems is a rotor structure of a permanent magnet type rotating machine in which permanent magnets are arranged radially with respect to the rotating shaft. A rotor core in which a shaft is inserted and rotates integrally with the shaft; and a plurality of main permanent magnets that are radially embedded at positions separated from the shaft of the rotor core to generate a main magnetic flux. A plurality of auxiliary permanent magnets embedded between the main permanent magnet and the shaft of the rotor core, the residual magnetic flux density being high with respect to the main permanent magnet. It is provided with a connecting portion that connects between the rotor core pieces located on both sides of the magnet in the circumferential direction, and the auxiliary permanent magnet has the same magnetization direction as that of the main permanent magnet arranged to face the radial direction. And before adjoining in the circumferential direction Flux of the main permanent magnet in the rotor core pieces is characterized in that it is arranged to prevent a short-circuit.

  The rotor structure of a permanent magnet type rotating machine according to a second aspect of the present invention for solving the above problem is the rotor structure of the permanent magnet type rotating machine according to the first aspect of the present invention, wherein the auxiliary permanent magnet is the shaft. And the main permanent magnet between the main permanent magnet and the auxiliary permanent magnet of the connecting portion, and are adjacent to each other in the circumferential direction. The magnetic flux of the main permanent magnet is prevented from being short-circuited between the rotor core pieces.

  A rotor structure of a permanent magnet type rotating machine according to a third aspect of the present invention for solving the above-described problems is the rotor structure of the permanent magnet type rotating machine according to the first aspect of the present invention, wherein the auxiliary permanent magnet is connected to the shaft. By magnetically saturating between the auxiliary permanent magnets disposed between the main permanent magnets and on the side of the main permanent magnets and facing the rotor core piece of the connecting portion, Further, the magnetic flux of the main permanent magnet is prevented from being short-circuited between the adjacent rotor core pieces.

  According to the rotor structure of the permanent magnet type rotating machine according to the present invention described above, the rotor core is an integral structure, and the permanent magnet generating the main magnetic flux is a permanent magnet having a low residual magnetic flux density such as a ferrite magnet. Can prevent leakage magnetic flux and provide a rotating machine with high magnetic flux density in the gap.

It is sectional drawing which shows the rotor structure of the permanent magnet type rotary machine which concerns on Example 1 of this invention. It is sectional drawing which shows the rotor core of the rotor structure of the permanent magnet type rotary machine which concerns on Example 1 of this invention. It is sectional drawing which shows the rotor structure of the permanent magnet type rotary machine which concerns on Example 2 of this invention. It is sectional drawing which shows the rotor core of the rotor structure of the permanent magnet type rotary machine which concerns on Example 2 of this invention.

  Hereinafter, a rotor structure of a permanent magnet type rotating machine according to the present invention will be described with reference to the drawings.

  The rotor structure of the permanent magnet type rotating machine according to the first embodiment of the present invention will be described in detail with reference to FIGS.

  As shown in FIG. 1, in the rotor structure of the permanent magnet type rotating machine according to the present embodiment, the rotor 1 is inserted into a shaft 2 made of a non-magnetic material and rotates integrally with the shaft 2. Compared with the core 11, the ferrite magnets 12 as a plurality of (8 in FIG. 1) main permanent magnets that are radially embedded in the rotor core 11 and generate the main magnetic flux, and the ferrite magnets 12 that are also embedded in the rotor core 11 Thus, a plurality of (eight in FIG. 1) auxiliary permanent magnets 13 having high residual magnetic flux density are provided.

  As shown in FIG. 2, the rotor core 11 has a shaft hole 111 formed in the axial center and into which the shaft 2 is fitted, and is radially arranged with a gap between the shaft hole 111 and the shaft hole 111 on the radially outer side of the shaft hole 111. A plurality of (the same number as the ferrite magnet 12; eight in FIG. 2) first magnet holes 112 and a plurality (the same number as the neodymium magnets) disposed in the gap between the shaft hole 111 and the first magnet hole 112. 2 in FIG. 2) second magnet holes 113.

  The first magnet hole 112 is a through hole having a substantially rectangular shape in cross-section, and is arranged at equal intervals in the circumferential direction, and the ferrite magnet 12 is inserted therein. In the present embodiment, the first magnet hole 112 has a shape in which the rotor core 11 is cut out from the outer peripheral surface side, and its radially outer end portion is circumferential in order to constrain the radial position of the ferrite magnet 12. The width of is narrow.

  As a result, the ferrite magnet 13 is disposed radially inward by a predetermined distance with respect to the outer diameter of the rotor core 11, and the rotation located between the first magnet holes 112 adjacent to each other in the circumferential direction. The child core piece 114 has a radially outer end portion that is separated from a radially outer end portion of the rotor core piece 114 adjacent in the circumferential direction.

  Further, the second magnet hole 113 is a through hole having a substantially rectangular shape in cross section, and similarly to the first magnet hole 112, the second magnet hole 113 is arranged at equal intervals in the circumferential direction, and the neodymium magnet 13 is inserted therein. In the present embodiment, the second magnet hole 113 has a shape in which the rotor core 11 is cut out from the shaft hole 111 side, and has a gap with the first magnet hole 112. The gap serves as a connecting portion 115 that connects the rotor core pieces 114 adjacent to each other in the circumferential direction.

  In FIG. 1, an arrow indicated by a thick line indicates the magnetization direction of the ferrite magnet 12, and an arrow indicated by a thin line indicates the magnetization direction of the neodymium magnet 13. As shown in FIG. 1, the ferrite magnet 12 and the neodymium magnet 13 that are opposed to each other with the coupling portion 115 interposed therebetween are inserted into the first magnet hole 112 and the second magnet hole 113 so that the magnetization directions are equal to each other. ing.

  Here, the magnetic pole appearing on the stator-side surface (not shown) of the rotor core 11 is constituted by the main magnetic flux generated by the two ferrite magnets 12 magnetized in the direction indicated by the arrows in FIG. 1 per magnetic pole.

  At this time, in the rotor structure of the permanent magnet type rotating machine according to the present embodiment, the connecting portion 115 positioned between the ferrite magnet 12 and the neodymium magnet 13 was magnetized in the direction indicated by the arrow in FIG. By magnetically saturating with the magnetic flux of the neodymium magnet 13, the magnetic flux of the ferrite magnet 12 is prevented from being short-circuited between the N pole and the S pole, and the amount of main magnetic flux constituting the magnetic pole is increased to increase the magnetic flux density in the gap. Can do.

  Further, since the rotor core 11 is integrated, there is no need for a process of integrating the divided rotor core with a permanent magnet and a shaft as in Patent Document 3 described above, and the rotor 1 and a stator (not shown) The air gap between them can be made small and the rotor 1 can be integrated with high accuracy. The amount of the neodymium magnet 13 used is not limited to the above-described embodiment, and the amount used is minimized based on the stress acting on the connecting portion 115 and the magnitude of the magnetic flux density in the gap. It is preferable to determine the magnet shape.

  According to the rotor structure of the permanent magnet type rotating machine according to the above-described embodiment, the rotor core 1 has an integral structure, and a permanent magnet having a low residual magnetic flux density such as a ferrite magnet 12 as a permanent magnet that generates a main magnetic flux. Even in the case of using a rotating machine, leakage magnetic flux can be prevented and a rotating machine having a high magnetic flux density in the gap can be provided.

  Further, as a means for suppressing torque pulsation in a permanent magnet type rotating machine in which permanent magnets are arranged radially with respect to the rotating shaft, the outer diameter of the rotor core 11 is large at the center of the magnetic pole and small between the poles. If you want to change the curvature of the stator side surface of the rotor core, for example, if the rotor core is separated, it takes many members and man-hours to maintain the gap accurately. If the accuracy is poor, the motor characteristics may be deteriorated such as an increase in torque pulsation. On the other hand, in the rotor structure of the permanent magnet type rotating machine according to this embodiment, the rotor core 11 is integrated. Since the gap accuracy depends only on the machining accuracy of the rotor core 11, the rotor 1 can be easily assembled by press fitting and shrink fitting.

  The rotor structure of the permanent magnet type rotating machine according to the second embodiment of the present invention will be described in detail with reference to FIGS.

  As shown in FIGS. 3 and 4, the rotor structure of the permanent magnet type rotating machine according to the present embodiment is the same as the rotor structure of the permanent magnet type rotating machine according to the first embodiment shown in FIGS. On the other hand, the number and arrangement of neodymium magnets are different. The other structure is substantially the same as the rotor structure of the permanent magnet type rotating machine according to the first embodiment. Hereinafter, the members having the same functions as those described in the first embodiment are given the same names, and are described in detail. Description is omitted.

  As shown in FIG. 3, in the rotor structure of the permanent magnet type rotating machine according to the present embodiment, the rotor 3 is inserted into a shaft 2 made of a non-magnetic material and rotates integrally with the shaft 2. The core 31, a plurality of (8 in FIG. 3) ferrite magnets 32 that are radially embedded in the rotor core 31 and generate main magnetic flux, and the residual magnetic flux density that is also embedded in the rotor core 31 compared to the ferrite magnet 32. And a plurality of (16 in FIG. 3) neodymium magnets 33.

  As shown in FIG. 4, the rotor core 31 is arranged radially with a shaft hole 311 formed in an axial center portion into which the shaft 2 is inserted, and the shaft hole 311 radially outside the shaft hole 311. A plurality of (the same number as the ferrite magnet 32; eight in FIG. 4) first magnet holes 312 and a plurality (the same number as the neodymium magnets) disposed in the gap between the shaft hole 311 and the first magnet hole 312. (16 in FIG. 4) second magnet holes 313.

  The first magnet hole 312 is a substantially rectangular through hole in cross section, and is disposed at equal intervals in the circumferential direction, and the ferrite magnet 32 is inserted therein.

  The second magnet hole 313 is a substantially rectangular through hole in a sectional view, and is disposed with a gap in the circumferential direction, into which the neodymium magnet 33 is inserted. In the present embodiment, the second magnet hole 313 is formed by cutting out both ends in the circumferential direction with respect to the inner surface in the radial direction of the first magnet hole 312 with respect to one first magnet hole 312. It consists of two small magnet holes 313a and 313b. In other words, a configuration in which small magnet holes 313a and 313b are respectively arranged on both sides in the circumferential direction of a radially inner base end portion (hereinafter referred to as a joint) 316 of the rotor core piece 314 with respect to one rotor core piece 314. It has become.

  Thereby, the second magnet hole 313 is in a state in which the small magnet holes 313a and the small magnet holes 313b are alternately arranged with respect to the circumferential direction, and the small magnet holes 313a and the small magnet holes 313b are respectively surrounded. It is in the state arrange | positioned at equal intervals with respect to the direction.

  In FIG. 3, an arrow indicated by a thick line indicates the magnetization direction of the ferrite magnet 32, and an arrow indicated by a thin line indicates the magnetization direction of the neodymium magnet 33. As shown in FIG. 3, the ferrite magnets 32 and the neodymium magnets 33 arranged radially inside are inserted into the first magnet hole 312 and the second magnet hole 313, respectively, so that the magnetization directions are equal. ing. Thereby, the neodymium magnets 33 located on both sides in the circumferential direction of the joint 316 are in a state where the N poles or the S poles face each other.

  The second magnet hole 313 has a gap with the shaft hole 311, and the gap between the shaft hole 311 and the first magnet hole 312 causes the rotation adjacent to each other in the circumferential direction. A connecting portion 315 that connects the child core pieces 314 is formed.

  Here, the magnetic pole that appears on the stator-side surface (not shown) of the rotor core 31 is constituted by a main magnetic flux generated by two ferrite magnets 32 that are magnetized in the direction indicated by the arrows in FIG.

  At this time, in the rotor structure of the permanent magnet type rotating machine according to the present embodiment, the magnetic flux of the neodymium magnet 33 which is disposed so as to face the joint 316 across the joint 316 and is magnetized in the direction indicated by the arrow in FIG. By magnetic saturation, the magnetic flux of the ferrite magnet 32 can be prevented from being short-circuited between the N pole and the S pole, the amount of main magnetic flux constituting the magnetic pole can be increased, and the magnetic flux density in the gap can be increased.

  Further, since the rotor core 31 is integral, there is no need for a process of integrating the divided rotor core with a permanent magnet and a shaft as in Patent Document 3 described above, and the rotor 3 and a stator (not shown) The air gap between them can be made small and the rotor 1 can be integrated with high accuracy. In addition, the usage-amount of the neodymium magnet 33 is not limited to this Example mentioned above, If the usage-amount and magnet shape are determined based on the stress which acts on the connection part 315, and the magnitude | size of the magnetic flux density in a gap. Is preferred.

  According to the rotor structure of the permanent magnet type rotating machine according to the present embodiment described above, the rotor core 3 has an integral structure, like the rotor structure of the permanent magnet type rotating machine according to the first embodiment described above. Even when a permanent magnet having a low residual magnetic flux density such as a ferrite magnet 12 is used as a permanent magnet for generating magnetic flux, leakage magnetic flux can be prevented and a rotating machine having a high magnetic flux density in the gap can be provided.

  Further, as a means for suppressing torque pulsation in a permanent magnet type rotating machine in which permanent magnets are arranged radially with respect to the rotating shaft, the outer diameter of the rotor core 31 is large at the center of the magnetic pole and small between the poles. If you want to change the curvature of the stator side surface of the rotor core, for example, if the rotor core is separated, it takes many members and man-hours to maintain the gap accurately. If the accuracy is poor, the motor characteristics may be deteriorated such as an increase in torque pulsation. On the other hand, in the rotor structure of the permanent magnet type rotating machine according to this embodiment, the rotor core 31 is integrated. The accuracy of the gap depends only on the processing accuracy of the original rotor core 31, and the rotor 1 can be easily assembled by press fitting and shrink fitting.

  The present invention relates to a rotor structure of a permanent magnet type rotating machine, and is particularly suitable for application to a rotor structure of a permanent magnet type rotating machine in which permanent magnets are arranged radially with respect to a rotating shaft.

DESCRIPTION OF SYMBOLS 1,3 Rotor 2 Shaft 11,31 Rotor core 12,32 Ferrite magnet 13,33 Neodymium magnet 111,311 Shaft hole 112,312 First magnet hole 113,313 Second magnet hole 114,314 Rotor core piece 115 , 315 Connection part 316 Joint

Claims (3)

In the rotor structure of a permanent magnet type rotating machine in which permanent magnets are arranged radially with respect to the rotating shaft,
The rotor is
A rotor core that engages with the shaft and rotates integrally with the shaft;
A plurality of main permanent magnets that are radially embedded in positions separated from the shaft of the rotor core and generate a main magnetic flux;
A plurality of auxiliary permanent magnets embedded between the main permanent magnet and the shaft of the rotor core having a high residual magnetic flux density with respect to the main permanent magnet;
The rotor core includes a connecting portion that connects between rotor core pieces located on both sides in the circumferential direction of the main permanent magnet,
The auxiliary permanent magnet has a magnetization direction that is the same as that of the main permanent magnet arranged opposite to the radial direction and between the rotor core pieces adjacent to the circumferential direction. A rotor structure for a permanent magnet type rotating machine, wherein the rotor structure is arranged to prevent magnetic flux from being short-circuited. The auxiliary permanent magnet is disposed between the shaft and the main permanent magnet and on the shaft side, and magnetically saturates between the main permanent magnet and the auxiliary permanent magnet of the connecting portion, The rotor structure of the permanent magnet type rotating machine according to claim 1, wherein the magnetic flux of the main permanent magnet is prevented from being short-circuited between the rotor core pieces adjacent to each other in the circumferential direction. The auxiliary permanent magnet is disposed between the shaft and the main permanent magnet and on the main permanent magnet side, and magnetic saturation occurs between the auxiliary permanent magnets facing each other across the rotor core piece of the connecting portion. The rotor structure of the permanent magnet type rotating machine according to claim 1, wherein the magnetic flux of the main permanent magnet is prevented from being short-circuited between the rotor core pieces adjacent to each other in the circumferential direction. .

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