JP2008187828A - Rotor of permanent magnet type rotary electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotor of a permanent magnet type rotary electric machine, which holds permanent magnets disposed on the external circumferential surface of a rotor core, and enables manufacture of a holding circle having soft magnetic phase portions corresponding to permanent magnets and non-magnetic phase portions sandwiched between the soft magnetic portions which are provided alternately, and can be easily assembled to a rotor core of the holding circle. <P>SOLUTION: The rotor 14 has a structure in which a plurality of permanent magnets 17 are disposed on the external circumferential surface of the rotor core 15 and a holding circle 18 disposed in a state of contacting the external circumferential surface of the permanent magnets 17 is provided. The holding circle 18 is constituted so that a circle made of an austenite stainless steel is subjected to partial plastic processing and portions 18a corresponding to the permanent magnets 17 can form a soft magnetic phase and portions 18b corresponding to spaces of adjacent permanent magnets 17 can form a non-magnetic phase. The holding circle 18 is fixed on the external circumferential surface of the rotor core 15 by welding in a portion 18b. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rotor of a permanent magnet type rotating electrical machine.

  As a rotor of a permanent magnet type rotating electric machine, there is one in which a permanent magnet is bonded to the outer peripheral surface of a rotor iron core. If the permanent magnet is simply bonded to the outer peripheral surface of the rotor core, the adhesive cannot withstand the tensile force of centrifugal force during high-speed rotation, and the permanent magnet may be scattered. In order to prevent the permanent magnets from scattering, a retaining ring made of a nonmagnetic material is fitted into the outer peripheral surface of the permanent magnet to fix the permanent magnet to the rotor core.

  When a nonmagnetic material is used for the retaining ring, the retaining ring acts as a gap magnetically. For this reason, increasing the thickness of the retaining ring is the same as increasing the gap (gap) with the stator (stator), which is not preferable for motor characteristics such as torque reduction. On the other hand, when a ferromagnetic material such as steel is used for the holding ring, the leakage magnetic flux that flows from the magnetic pole to the adjacent magnetic pole through the holding ring increases, so that the amount of the main magnetic flux decreases and the torque is also reduced.

In order to eliminate such problems, the retaining ring surrounding the outer periphery of the permanent magnet is made of austenitic steel that exhibits ferromagnetism by cold working, and a part of the retaining ring is heated substantially after the cold working, so that the non-magnetic phase is partially partially heated. A rotator (rotor) has been proposed (see Patent Document 1). As shown in FIG. 4, the rotor described in Patent Document 1 has a permanent magnet 32 attached around the rotor yoke 31 and a holding ring 33 attached around the permanent magnet 32. The retaining ring 33 is made by cutting a thick austenitic stainless steel pipe and using cold working to obtain a predetermined ring size. The portion 33a located between the magnetic poles of the retaining ring 33 is not heated by laser irradiation. It is considered magnetic.
JP-A-6-133480

  When the retaining ring 33 of the rotor described in Patent Document 1 is formed, it is heated with a laser or the like in order to form a nonmagnetic portion in a ferromagnetic pipe formed with a predetermined ring size by applying cold working. An annealing process is required. At that time, when local heating is applied to partially demagnetize, there is a concern that the pipe (tube) may be distorted due to thermal effects.

  Further, in the configuration in which the retaining ring 33 is a circular tube having no irregularities and is merely fitted to the outside of the permanent magnet 32, the ferromagnetic phase and the nonmagnetic phase are apparently the same, so when assembling the retaining ring 33, There is a possibility that the retaining ring 33 is assembled in a state where the ferromagnetic phase does not correspond to the permanent magnet 32. Even when the ferromagnetic phase of the holding ring 33 is assembled in a state corresponding to the permanent magnet 32, the holding ring 33 and the permanent magnet 32 move relative to each other in the circumferential direction of the rotor, and the ferromagneticity of the holding ring 33 is reached. There is a possibility that the phase is shifted to a position not corresponding to the permanent magnet 32.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to hold a permanent magnet disposed on an outer peripheral surface of a rotor core, and to form a soft magnetic phase portion corresponding to the permanent magnet and the soft magnetism. It is an object of the present invention to provide a rotor of a permanent magnet type rotating electrical machine that is easy to manufacture a retaining ring having alternating nonmagnetic phase portions sandwiched between phase portions and to assemble the retaining ring to a rotor core.

  In order to achieve the above object, according to the first aspect of the present invention, a plurality of permanent magnets are disposed on the outer peripheral surface of the rotor core, and a retaining ring is disposed in contact with the outer peripheral surface of the permanent magnet. It is the rotor of the permanent magnet type rotary electric machine provided. The retaining ring is formed by partially plasticizing a ring made of austenitic stainless steel, a portion corresponding to the permanent magnet forms a soft magnetic phase, and a portion corresponding to between adjacent permanent magnets It is comprised so that a nonmagnetic phase may be comprised.

  In this invention, the retaining ring is formed by partially plasticizing an austenitic stainless steel ring (pipe). In the circular ring, a portion subjected to plastic working becomes a soft magnetic phase, and a portion not subjected to plastic working retains a nonmagnetic phase. Therefore, unlike the prior art, useless processing of returning the portion once made to the ferromagnetic phase to the nonmagnetic phase again becomes unnecessary. In addition, unlike the prior art, when manufacturing the retaining ring, there is a concern that the retaining ring may be distorted due to thermal effects because it is not necessary to partially heat the portion that has been converted to the non-magnetic phase. Absent. Further, in the present invention, the plastic working is partially performed on the ring (pipe), so that the portion subjected to the plastic working has a distance from the center of the circular ring to the portion not subjected to the plastic working. It will be in a different state. Therefore, unlike the conventional technology, the soft magnetic phase part and the non-magnetic phase part can be easily distinguished, and when the retaining ring is assembled, the soft magnetic phase part can be easily matched with the permanent magnet. Can be assembled.

  According to a second aspect of the present invention, in the first aspect of the present invention, the portion subjected to the plastic working is formed as a bulging portion that bulges toward the outside of the ring, and the permanent magnet Is fixed to the outer peripheral surface of the rotor core by the holding ring in a state in which the relative movement in the circumferential direction of the rotor core with respect to the holding ring is restricted by engaging with the bulging portion. In the present invention, when the retaining ring is assembled, the soft magnetic phase portion can be automatically assembled in a state where it corresponds to the permanent magnet automatically by assembling the bulging portion so as to cover the permanent magnet.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the retaining ring is fixed to the outer peripheral surface of the rotor core by welding at the portion of the nonmagnetic phase.
In the configuration in which the retaining ring is merely fitted to the outside of the permanent magnet, if the retaining ring is thin, the strength is insufficient, and the retaining ring may be deformed in the direction of loosening due to centrifugal force during high-speed rotation. On the other hand, if the retaining ring is too thick, deformation that causes loosening can be prevented, but the ferromagnetic stainless steel constituting the retaining ring can be used for electromagnetic steel sheets and silicon steel sheets that are the material of the rotor core and stator (stator). In comparison, there is a problem that the magnetic resistance is high, resulting in a decrease in rotational torque. However, in this invention, since the retaining ring is fixed to the rotor core by welding, the centrifugal force during high-speed rotation can be obtained even when the rotor is assembled and used in a rotating electrical machine even if the retaining ring is thin. Therefore, it is possible to prevent deformation so as to be loosened. Therefore, by reducing the thickness of the retaining ring, the magnetic resistance between the permanent magnet and the stator can be further reduced, and the torque can be improved.

  According to the present invention, the permanent magnet disposed on the outer peripheral surface of the rotor core is held, and the soft magnetic phase portion corresponding to the permanent magnet and the nonmagnetic phase portion sandwiched between the soft magnetic phase portions are alternately arranged. It is possible to provide a rotor of a permanent magnet type rotating electrical machine in which the retaining ring having the retaining ring can be easily assembled and the retaining ring can be assembled to the rotor core.

Hereinafter, an embodiment in which the present invention is embodied in a surface magnet type electric motor as a permanent magnet type rotating electrical machine will be described with reference to FIGS. 1 and 2.
As shown in FIG. 1, the stator (stator) 11 has a cylindrical shape, and a plurality of teeth 12 are provided at equal intervals on the inner side. A coil (winding) 13 is wound around the tooth 12. The winding method of the coil 13 may be distributed winding or concentrated winding.

  A rotor (rotor) 14 is disposed inside the stator 11. The rotor 14 includes a rotor core 15 in which a plurality of (for example, several tens) disk-shaped electromagnetic steel plates made of a high permeability material such as an electromagnetic steel plate are stacked, and a rotor shaft (rotating shaft) inserted through the center of the rotor core 15. 16). The electromagnetic steel plates are integrally fixed with an adhesive or the like as necessary. The rotor 14 is rotatably supported by a bearing of a housing (not shown) via a rotor shaft 16 with the outer peripheral surface of the rotor core 15 spaced apart from the teeth 12.

  On the outer peripheral surface of the rotor core 15, a plurality of arc-shaped permanent magnets 17 (six in this embodiment) whose cross-sectional shape is centered on the rotation center of the rotor core 15 are arranged at equal intervals in the circumferential direction. Yes. Each permanent magnet 17 is fixed to the rotor core 15 with a holding ring 18 arranged in contact with the outer peripheral surface of the permanent magnet 17. As the permanent magnet 17, a rare earth magnet having a stronger magnetic force than other permanent magnets is used. In this embodiment, a neodymium-iron-boron magnet (Nd-Fe-B magnet) is used.

  The retaining ring 18 is a part corresponding to a portion between adjacent permanent magnets 17 by forming a soft magnetic phase in a portion 18 a corresponding to the permanent magnet 17 by performing plastic processing on a ring made of austenitic stainless steel. It is comprised so that 18b may comprise a nonmagnetic phase. The retaining ring 18 is formed as a bulging portion in which a plastic-worked portion 18a bulges toward the outer side of the annular ring, and the permanent magnet 17 engages with the bulging portion and In a state where relative movement of the rotor core 15 in the circumferential direction is restricted, the rotor core 15 is fixed to the outer peripheral surface of the rotor core 15 by the holding ring 18. The retaining ring 18 is formed in such a thickness that the deformation occurs such that the retaining ring 18 is loosened by centrifugal force during high-speed rotation when the retaining ring 18 is simply fitted to the outside of the permanent magnet 17. . The rotor core 15 is formed with convex portions 15a at positions corresponding to between the adjacent permanent magnets 17, and the holding ring 18 is fixed to the convex portions 15a of the rotor core 15 by welding at a nonmagnetic phase portion 18b. .

Next, a method for manufacturing the rotor 14 configured as described above will be described.
First, a method for manufacturing the retaining ring 18 will be described. When manufacturing the retaining ring 18, an austenitic stainless steel ring (pipe) is prepared, and plastic processing is performed at a desired location by roll processing from the inside. For example, as shown in FIG. 2, a pressing process is performed with a roll 22 at a predetermined position inside an austenitic stainless steel ring (pipe) 21 using a mold 20 having a recess 20 a. The predetermined position is a portion corresponding to the permanent magnet 17 when it is disposed outside the permanent magnet 17 disposed on the outer peripheral surface of the rotor core 15 in a state where the annular ring 21 is formed on the retaining ring 18. In this embodiment, since the rotor 14 has six permanent magnets 17, roll processing with the rolls 22 is performed at six positions at predetermined intervals along the circumferential direction of the ring 21.

  Since the circumferential direction length of the ring-processed portion of the annular ring 21 is increased, the annular ring 21 expands in the radial direction, the expansion amount is restricted by the recess 20a, and the width of the permanent magnet 17 (corresponding to the circumferential direction of the rotor core 15). The portion 18a is formed as a bulging part having the same width as the length of The bulge is softened by processing-induced transformation. When the six rolls are finished, the retaining ring 18 is completed in which the soft magnetic phase portions 18a and the nonmagnetic phase portions 18b alternately exist at predetermined intervals in the circumferential direction.

  Further, from a high permeability material having a plurality of (for example, several tens) substantially disk-shaped electromagnetic steel plates having convex portions at predetermined intervals on the periphery, and having convex portions 15a at equal intervals in the circumferential direction on the outer peripheral surface. The resulting rotor core 15 is formed. A plurality of permanent magnets 17 are arranged on the outer peripheral surface of the rotor core 15 at equal intervals in the circumferential direction so that each permanent magnet 17 is located between the convex portions 15a. The permanent magnet 17 is attracted to the outer peripheral surface of the rotor core 15 by its magnetic force.

  Then, with respect to the rotor core 15 having the permanent magnet 17 adsorbed on the outer peripheral surface, the retaining ring 18 is disposed in a state where the portion 18a corresponds to the permanent magnet 17, and the retaining ring 18 is disposed in the nonmagnetic phase portion 18b. Welding to the convex portion 15a. In order to minimize the processing-induced transformation magnetization due to residual stress and strain after welding, it is preferable to perform welding with low heat input and deep penetration like electron beam welding or pulse laser welding. In this way, the magnetization of the portion 18b is minimized only in the vicinity of the weld bead, and the portion slightly away from the beam remains in the nonmagnetic austenite structure, so that a partial heat treatment such as local magnetic annealing is not required. It is only necessary to lightly heat only the beam welded portion to prevent cooling cracks. Thus, the manufacture of the rotor 14 is completed.

Next, the operation of the electric motor configured as described above will be described.
When the motor is driven in a loaded state, the coil 13 of the stator 11 is energized and a rotating magnetic field acts on the rotor 14. Then, the rotor 14 is rotated by the action of the rotating magnetic field and the magnetic flux of the permanent magnet 17. When the entire retaining ring 18 for preventing the permanent magnet 17 from scattering during high-speed rotation is formed of a non-magnetic material (non-magnetic material), the retaining ring 18 acts magnetically as a gap, and the stator 11 (teeth 12) and the permanent magnet 17 are the same as the gap (air gap) is increased, and the motor characteristics such as torque reduction are reduced. On the other hand, when the entire retaining ring 18 is formed of a ferromagnetic material, the leakage magnetic flux that flows from the magnetic pole to the adjacent magnetic pole through the retaining ring 18 increases, so that the amount of the main magnetic flux decreases and the torque is reduced. Bring.

  However, in this embodiment, the retaining ring 18 includes a portion 18a corresponding to the permanent magnet 17 as a soft magnetic phase, and a nonmagnetic phase portion 18b exists between the soft magnetic bodies. Therefore, the magnetic resistance between the stator 11 and the permanent magnet 17 is reduced. As a result, the amount of magnetic flux that goes out of the permanent magnet 17 toward the stator 11 increases, and the torque is improved. Since the holding ring 18 is fixed to the rotor core 15 by welding, even if the thickness of the holding ring 18 is reduced, the holding ring 18 is loosened by the centrifugal force when the rotor 14 rotates at high speed. Deformation is prevented. Therefore, by reducing the thickness of the retaining ring 18, the magnetic resistance between the permanent magnet 17 and the stator 11 can be further reduced, and the torque can be improved. In addition, since the soft magnetic phase portion 18a is partitioned by the nonmagnetic phase portion 18b, a part of the magnetic flux emitted from the magnetic pole is prevented from flowing into the adjacent magnetic pole through the retaining ring 18 as a leakage magnetic flux. The As a result, a decrease in the amount of main magnetic flux is suppressed, contributing to an improvement in torque.

According to this embodiment, the following effects can be obtained.
(1) The rotor 14 includes a plurality of permanent magnets 17 disposed on the outer peripheral surface of the rotor core 15 and a holding ring 18 disposed in contact with the outer peripheral surface of the permanent magnet 17. 18 is made of austenitic stainless steel, a portion 18a corresponding to the permanent magnet 17 forms a soft magnetic phase, and a portion 18b corresponding to between adjacent permanent magnets 17 forms a nonmagnetic phase. Therefore, in a state where the rotor 14 is assembled and used in a rotating electrical machine, the magnetic resistance between the permanent magnet 17 and the stator 11 is smaller than when the entire retaining ring 18 is formed of a nonmagnetic material, and Compared with the case where the entire holding ring 18 is made of a ferromagnetic material, a part of the magnetic flux emitted from the magnetic pole is prevented from leaking through the holding ring 18 and flowing to the adjacent magnetic pole. As a result, torque can be improved.

  (2) The retaining ring 18 is formed by partially plasticizing a ring (pipe) 21 made of austenitic stainless steel, and the part subjected to the plastic processing becomes a soft magnetic phase. The part not subjected to plastic working retains the nonmagnetic phase. Accordingly, the portion 18a subjected to the plastic working is in a state where the distance from the center of the holding ring 18 is different from the portion 18b not subjected to the plastic working. Therefore, unlike the prior art, the soft magnetic phase (ferromagnetic phase) portion 18a and the nonmagnetic phase portion 18b can be easily distinguished, and when the retaining ring 18 is assembled, the soft magnetic phase portion 18a is made permanent. It can be easily assembled in a state corresponding to the magnet 17.

  (3) The retaining ring 18 is formed as a bulging portion in which a plastic-worked portion 18a bulges toward the outside of the retaining ring 18, and the permanent magnet 17 is engaged with the bulging portion. The rotor core 15 is fixed to the outer peripheral surface of the rotor core 15 by the holding ring 18 in a state where relative movement of the rotor core 15 with respect to the holding ring 18 in the circumferential direction is restricted. Accordingly, when the retaining ring 18 is assembled, the soft magnetic phase portion 18a is automatically assembled in a state where it corresponds to the permanent magnet 17 automatically by assembling the portion (bulging portion) 18a so as to cover the permanent magnet 17. Can do. In addition, the gap between the soft magnetic phase portion 18a and the teeth 12 can be made smaller compared to the case where the soft magnetic phase portion 18a (bulging portion) is formed so as to protrude to the inside of the retaining ring 18. Can be further improved.

  (4) The retaining ring 18 is fixed to the rotor core 15 by welding at the nonmagnetic phase portion 18b. Therefore, even when the thickness of the retaining ring 18 is reduced, it is possible to prevent the rotor 14 from being deformed so as to be loosened by centrifugal force during high-speed rotation in a state where the rotor 14 is assembled and used in a rotating electrical machine. . Therefore, by reducing the thickness of the retaining ring 18, the magnetic resistance between the permanent magnet 17 and the stator 11 can be further reduced, and the torque can be further improved.

  (5) Since the rotor core 15 has convex portions 15a formed at regular intervals in the circumferential direction and the retaining ring 18 is welded to the convex portion 15a, the retaining ring 18 is welded to the rotor core 15 that does not have the convex portion 15a. Compared to the case, welding can be performed easily. When the portion 18b is welded to the rotor core 15 that does not have the convex portion 15a, it is necessary to process the portion 18b of the retaining ring 18 so as to be convex inward, so that the processing of the retaining ring 18 is troublesome. There is no need to perform any special processing.

  (6) When the retaining ring 18 is welded to the rotor core 15, welding with low heat input and deep penetration is performed, such as electron beam welding or pulse laser welding. Therefore, the magnetization of the portion 18b is minimized only in the vicinity of the weld bead, and the portion slightly away from the beam remains in the nonmagnetic austenite structure, so that a partial heat treatment such as local magnetic annealing is not required. It only needs to be heated after heating to prevent cooling cracks.

The embodiment is not limited to the above, and may be embodied as follows, for example.
O When manufacturing the holding ring 18, you may make it perform a press process with the roll 22 in the predetermined position by the roll process from the outer side of the ring 21 made from austenitic stainless steel. In this case, as shown in FIG. 3, the soft magnetic phase portion 18 a as a whole has a shape located inside the nonmagnetic phase portion 18 b that is not subjected to roll processing, but is in contact with the outer peripheral surface of the permanent magnet 17. The contact area is formed on an outwardly convex circular arc surface. Accordingly, even in this case, the retaining ring 18 can easily distinguish between the soft magnetic phase (ferromagnetic phase) portion 18a and the nonmagnetic phase portion 18b, and when the retaining ring 18 is assembled, The part 18a can be easily assembled in a state where it corresponds to the permanent magnet 17.

  ○ In the manufacturing method of the rotor 14, instead of performing the preparation of the rotor core in which a plurality of permanent magnets 17 are bonded to the outer peripheral surface of the rotor core 15 made of a high magnetic permeability material at equal intervals in the circumferential direction. A structure in which a plurality of permanent magnets 17 are bonded to the outer peripheral surface of the rotor core 15 at equal intervals in the circumferential direction may be prepared or purchased in advance.

The number of poles of the rotor 14, that is, the number of permanent magnets 17 is not limited to six.
The permanent magnet 17 is not limited to the Nd—Fe—B magnet, and may be a rare earth magnet (samarium-cobalt magnet) other than the Nd—Fe—B magnet, or a magnet other than the rare earth magnet. However, the use of rare earth magnets makes it easier to reduce the size of the rotating electrical machine.

○ The rotating electrical machine is not limited to an electric motor but may be applied to a generator.
The following technical idea (invention) can be understood from the embodiment.
(1) In the invention according to claim 3, the rotor core has convex portions formed at equal intervals in the circumferential direction, and the holding ring is welded to the convex portions.

(2) In the invention described in claim 3 or the technical idea (1), the welding is spot welding.
(3) A method for manufacturing a rotor of a permanent magnet type rotating electrical machine, wherein a plurality of permanent magnets are disposed on the outer peripheral surface of the rotor core, and a retaining ring is disposed in contact with the outer peripheral surface of the permanent magnet. There,
By applying plastic working at a predetermined interval in the circumferential direction to an austenitic stainless steel ring, a portion corresponding to the permanent magnet forms a soft magnetic phase, and an adjacent permanent magnet is formed. The holding ring formed so that the portion corresponding to the non-magnetic phase forms a non-magnetic phase is arranged so that the portion of the non-magnetic phase corresponds to the space between the permanent magnets arranged on the outer peripheral surface of the rotor core. A method of manufacturing a rotor of a permanent magnet type rotating electrical machine in which a ring is welded to the rotor core in a nonmagnetic phase portion.

The schematic diagram of the rotary electric machine of one Embodiment. The model perspective view which shows the manufacturing state of a holding | maintenance ring. The partial schematic diagram of the rotary electric machine of another embodiment. The schematic diagram of the rotor of a prior art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 14 ... Rotor, 15 ... Rotor core, 17 ... Permanent magnet, 18 ... Holding ring, 18a, 18b ... Part, 21 ... Ring.

Claims (3)

A rotor of a permanent magnet type rotating electrical machine including a plurality of permanent magnets arranged on the outer peripheral surface of the rotor core and a holding ring arranged in contact with the outer peripheral surface of the permanent magnet,
The retaining ring is formed by partially plasticizing an austenitic stainless steel ring so that a portion corresponding to the permanent magnet forms a soft magnetic phase, and a portion corresponding to between adjacent permanent magnets is nonmagnetic. A rotor of a permanent magnet type rotating electrical machine, wherein the rotor is configured to form a phase.   The portion subjected to the plastic working is formed as a bulging portion that bulges toward the outside of the annular ring, and the permanent magnet engages with the bulging portion to surround the rotor core with respect to the holding ring. The rotor of a permanent magnet type rotating electrical machine according to claim 1, wherein the rotor is fixed to the outer peripheral surface of the rotor core by the holding ring in a state where relative movement in a direction is restricted.   The rotor of a permanent magnet type rotating electric machine according to claim 1, wherein the retaining ring is fixed to the outer peripheral surface of the rotor core by welding in the nonmagnetic phase portion.

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