JP2016220286A - Device and method of manufacturing embedded magnet type rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device of manufacturing an embedded magnet type rotor capable of performing stabilization treatment of a permanent magnet without using extra facilities and to provide a method of manufacturing the same.SOLUTION: After the completion of the magnetization of a magnet material 36, an opposite magnetic field is applied to a rotor core 12 (permanent magnet 13) in a high-temperature state by using a magnetic field generated by a magnetized mold 43. Namely, a rotor core 12 is rotated by at least an angle obtained by dividing 360° by the number of magnetic poles of the rotor. By applying an opposite magnetic field which is a magnetic field opposite to the magnetization direction to the permanent magnet 13 after magnetization, a part where is easily demagnetized in the permanent magnet 13 is demagnetized. When magnetization is completed, the permanent magnet 13 is kept in a certain high-temperature state. Therefore, a demagnetizing effect by heating for stabilizing the magnetic characteristics of the permanent magnet 13 is obtained.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an embedded magnet rotor manufacturing apparatus and an embedded magnet rotor manufacturing method.

  Conventionally, an embedded magnet type motor in which a permanent magnet serving as a field source is embedded in a rotor core is known. As described in Patent Document 1, for example, rare earth bonded magnets may be employed as permanent magnets in addition to sintered magnets. A rotor using this bonded magnet is manufactured, for example, as follows. That is, while applying a magnetic field to the rotor core, the molten magnet material is injected and filled into the magnet slots of the rotor core. When the filled magnet material is cooled and solidified, the manufacture of the rotor is completed. Since the magnet material is magnetized while filling the magnet material into the magnet slot, the number of manufacturing steps of the rotor is reduced.

Japanese Patent Application Laid-Open No. 11-206075 JP 2006-294936 A

  The magnetic characteristics of the permanent magnet used in the rotor affect the torque generated by the motor. For this reason, the permanent magnet used for the rotor is required to have stable magnetic properties. However, demagnetization may occur in the permanent magnet. Demagnetization refers to a phenomenon in which an irreversible decrease in magnetic force occurs, for example, when a magnetized permanent magnet is heated, a reverse magnetic field is applied, or both are performed.

  Therefore, in order to suppress changes in the motor characteristics caused by demagnetization during use of the motor, a so-called withering process is performed on the permanent magnet of the rotor. The withering process refers to a process for stabilizing the magnetic characteristics of the permanent magnet. For example, as described in Patent Document 2, the permanent magnet is heat-treated at the highest temperature expected at the time of use or higher than the highest temperature. Thereby, demagnetization of the permanent magnet in use is suppressed. Conventionally, a reverse magnetic field may be applied to the rotor as a withering process.

  However, after the manufacture of the rotor is completed, an additional facility for heating or applying a reverse magnetic field to the permanent magnet or the rotor provided with the permanent magnet is necessary in order to perform the withering process separately.

  An object of the present invention is to provide an embedded magnet type rotor manufacturing apparatus and an embedded magnet type rotor manufacturing method capable of performing permanent magnet stabilization without using extra equipment.

  An apparatus for manufacturing an embedded magnet type rotor that can achieve the above object is as follows. That is, in an embedded magnet rotor manufacturing apparatus in which bonded magnets, which are a kind of permanent magnet, are embedded in a plurality of magnet holes provided in a core, magnetic fields having different polarities are alternately arranged along the circumferential direction of the core. A magnetizing device generated in the magnet, a filling device for filling the magnet hole of the core with a magnet material, and the bonded magnet obtained by magnetizing the magnet material filled in the magnet hole through application of the magnetic field. On the other hand, a drive source that rotates the core and the magnetizing device relative to each other until the magnetic field is applied as a reverse magnetic field that is a magnetic field in a direction opposite to the magnetization direction of the bond magnet.

  According to this configuration, the same magnetizing apparatus can be used to magnetize the magnet material and to stabilize and demagnetize the magnetized bonded magnet before use. There is no need for a dedicated device that generates a reverse magnetic field for stabilizing demagnetization before use.

  In the above-described embedded magnet type rotor manufacturing apparatus, it is preferable that the magnetizing device has a plurality of magnetic field generating sources that generate the magnetic field so as to surround the core. The drive source may be a rotary actuator coupled to the core.

According to this configuration, the core can be rotated relative to the plurality of magnetic field generation sources through driving of the rotary actuator.
In the above-described embedded magnet type rotor manufacturing apparatus, when a reverse magnetic field is applied to the bond magnet, at least one rotation angle of the core with respect to the position of the core when the magnet material is magnetized It is preferable to have a control device that controls the driving of the rotary actuator so that the core rotates by an angle obtained by dividing 360 ° by the number of magnetic poles of the rotor.

  According to this configuration, the magnetized bond magnet is rotated to a position corresponding to at least a magnetic field generation source adjacent to the magnetic field generation source that generates a magnetic field applied during magnetization. Since the plurality of magnetic field generation sources alternately generate magnetic fields having different polarities along the circumferential direction of the core, a magnetic field in a direction opposite to its own magnetization direction is applied to the magnetized bond magnet. Thereby, the stabilization demagnetization before using the magnetized bond magnet is performed.

  In the above-described embedded magnet type rotor manufacturing apparatus, a temperature sensor for detecting the temperature of the core may be provided. In this case, when the controller is heated to such an extent that the magnet material has fluidity, the temperature of the core detected through the temperature sensor is such that the magnet material having fluidity is solidified. The core may be rotated through the rotary actuator when the temperature drops to a threshold temperature set on the basis of the temperature.

  According to this configuration, a reverse magnetic field is applied in a state where the bonded magnet is solidified. That is, when the rotor is used in a state where the bonded magnet is solidified, stabilization demagnetization before use is performed on the bonded magnet in a state close to an actual usage state. For this reason, demagnetization during actual use of the rotor is suitably suppressed.

  In the manufacturing apparatus, the control device may include a counter that measures an elapsed time after the magnet material is filled in the magnet hole. In this case, when the magnet material is heated to such a degree that the magnet material has fluidity, the elapsed time detected through the counter reaches a temperature at which the magnet material having fluidity is solidified. The core may be rotated through the rotary actuator when a threshold time set based on the time required to decrease is reached.

  According to this configuration, a reverse magnetic field is applied in a state where the bonded magnet is solidified. That is, when the rotor is used in a state where the bonded magnet is solidified, stabilization demagnetization before use is performed on the bonded magnet in a state close to an actual usage state. For this reason, demagnetization during actual use of the rotor is suitably suppressed.

In the above-described embedded magnet type rotor manufacturing apparatus, the temperature at which the magnet material having fluidity is solidified is preferably set based on the temperature when the rotor is used.
According to this configuration, the stabilized demagnetization before use is performed on the bonded magnet in a state close to the temperature when the rotor is used. For this reason, demagnetization during actual use of the rotor is suitably suppressed.

In the above-described embedded magnet type rotor manufacturing apparatus, the magnetic field generation source preferably includes a permanent magnet that always generates the magnetic field or a coil that generates the magnetic field when energized.
As in this configuration, both the permanent magnet and the coil can be used as a magnetizing source or a source for generating a reverse magnetic field.

  In the above-described embedded magnet type rotor manufacturing apparatus, the filling device gives fluidity by heating the magnet material and injects the fluid material into the magnet hole of the core. It may be.

  In order to stabilize the magnetic properties of the bonded magnet, the bonded magnet may be heated. In this regard, according to the above configuration, the magnet material is magnetized while being filled in the magnet hole in a state of being heated to such a degree that it has fluidity. That is, the effect of stabilizing demagnetization by heating the bonded magnet can be obtained. For this reason, the heating apparatus for exclusive use which heats a bonded magnet anew is unnecessary.

  The manufacturing method of the interior magnet type rotor that can achieve the above object is as follows. That is, in a method of manufacturing an embedded magnet type rotor in which a bonded magnet, which is a kind of permanent magnet, is embedded in a plurality of magnet holes provided in a core, magnetic fields having different polarities are alternately arranged along the circumferential direction of the core. A first step of attaching the core to the magnetizing device generated in the second step, a second step of filling the magnet hole of the core with a magnet material, and a magnet material filled in the magnet hole through application of the magnetic field. The core and the magnetizing device are connected to each other up to a position where the magnetic field is applied as a reverse magnetic field that is a magnetic field opposite to the magnetization direction of the bond magnet with respect to the bond magnet obtained by being magnetized. A third step of relative rotation.

  According to this manufacturing method, by using the same magnetizing device, it is possible to perform magnetization demagnetization of the magnet material and stabilization demagnetization before using the magnetized bond magnet. There is no need for a dedicated device that generates a reverse magnetic field for stabilizing demagnetization before use.

  According to the interior magnet rotor manufacturing apparatus and the interior magnet rotor manufacturing method of the present invention, the permanent magnet stabilization process can be performed without using extra equipment.

The perspective view of an embedded magnet type | mold rotor. The perspective view which shows the state which decomposed | disassembled the manufacturing apparatus of an embedded magnet type | mold rotor. The top view which looked at the magnetization metal mold | die from the embedded magnet type | mold rotor side. The top view which looked at the magnetization metal mold | die from the embedded magnet type | mold rotor side. The top view which looked at the magnetization metal mold | die from the embedded magnet type | mold rotor side. The top view which looked at the other example of the magnetization metal mold | die from the interior magnet type | mold rotor side.

  Hereinafter, an embodiment of a manufacturing apparatus of an embedded magnet type rotor and a manufacturing method of an embedded magnet type rotor will be described. The embedded magnet type rotor constitutes an IPM motor (Interior Permanent Magnet Motor). The IPM motor is used as a generation source of steering assist force in an electric power steering device (EPS), for example.

<Structure of embedded magnet rotor>
First, the structure of the embedded magnet type rotor will be described.
As shown in FIG. 1, the rotor 11 has a cylindrical rotor core 12 formed by laminating a plurality of electromagnetic steel plates, and ten permanent magnets 13 embedded in the rotor core 12.

  An insertion hole 14 into which a motor rotation shaft (not shown) is inserted is provided at the center of the rotor core 12. The insertion hole 14 penetrates along the axial direction of the rotor core 12. A key groove 14 a is formed on the inner peripheral surface of the insertion hole 14. The key groove 14a is provided over the entire length of the insertion hole 14 in the axial direction. Further, around the insertion hole 14 of the rotor core 12, ten magnet holes 15 equal in number to the permanent magnets 13 are provided. Each magnet hole 15 penetrates along the axial direction of the rotor core 12. When the rotor core 12 is viewed from the axial direction, the magnet holes 15 are provided at regular intervals along the circumferential direction of the rotor core 12. Further, when the rotor core 12 is viewed from the axial direction, each magnet hole 15 has a V shape that opens from the inner peripheral surface of the rotor core 12 toward the outer peripheral surface.

  A permanent magnet 13 is embedded in each magnet hole 15. In this example, a resin-bonded bonded magnet is employed as the permanent magnet 13. This bonded magnet is manufactured by molding and magnetizing a mixture of magnet powder (magnetic powder) and synthetic resin (binder / binder) into a predetermined shape.

<Embedded magnet rotor manufacturing equipment>
Next, an apparatus for manufacturing an embedded magnet type rotor will be described.
As shown in FIG. 2, the manufacturing apparatus 21 includes an injection device 22, a magnetizing device 23, and a control device 24 that controls them.

  The injection device 22 includes a hopper 31, a heating cylinder 32, a heater 33, an injection screw 34, and an injection nozzle 35. The hopper 31 and the heater 33 are provided on the outer wall of the heating cylinder 32, respectively. The injection screw 34 is provided inside the heating cylinder 32. The injection nozzle 35 is provided at the distal end portion (right end portion in the drawing) of the heating cylinder 32.

  A granular magnet material (pellet) 36 is put into the hopper 31. The magnet material 36 is obtained by mixing a magnet powder such as a rare earth magnet with a synthetic resin and molding and solidifying it into a predetermined shape. As the synthetic resin, any of a thermoplastic resin and a thermosetting resin may be adopted as long as fluidity can be secured. The magnet material 36 put into the hopper 31 is fed into the heating cylinder 32. The magnet material 36 fed into the heating cylinder 32 is melted by receiving heat from the heater 33 while being fed toward the injection nozzle 35 through the rotation of the injection screw 34. The molten high-temperature magnet material 36 is injected from the injection nozzle 35 to the outside through the rotation of the injection screw 34.

The magnetizing device 23 has a case 41, a motor 42 and a magnetizing mold 43.
The case 41 is provided in a bottomed cylindrical shape with an upper portion opened by a nonmagnetic material. The motor 42 is provided at the bottom of the case 41. A connecting shaft 45 is connected to the rotating shaft 44 of the motor 42. The connecting shaft 45 projects through the center portion of the bottom wall of the case 41 and protrudes into the case 41. The connecting shaft 45 is provided to be rotatable relative to the case 41. A key 45 a that fits in the key groove 14 a of the rotor core 12 is provided in a portion of the connecting shaft 45 that is located inside the case 41. The key 45 a extends along the axial direction of the connecting shaft 45. However, the key 45 a is separated from the inner bottom surface of the case 41. The motor 42 is controlled by the control device 24.

  The magnetizing mold 43 has 20 permanent magnets 51 and 10 magnetizing yokes 52. As the permanent magnet 51, for example, a neodymium-iron-boron (Nd—Fe—B) sintered magnet is employed. The width of the permanent magnet 51 in the circumferential direction of the magnetizing mold 43 is set so as to increase from the center of the magnetizing mold 43 toward the outside along the radial direction. The width of the magnetizing yoke 52 in the circumferential direction of the magnetizing mold 43 is set so as to decrease from the center of the magnetizing mold 43 toward the outside along the radial direction. The magnetizing mold 43 has a cylindrical shape as a whole by combining the permanent magnet 51 and the magnetizing yoke 52.

  In the circumferential direction of the magnetizing mold 43, a magnetizing yoke 52 is interposed between the two permanent magnets 51, 51. In the circumferential direction of the magnetizing mold 43, different magnetic poles (N pole, S pole) are provided on the two sides of the permanent magnet 51. In the circumferential direction of the magnetizing mold 43, the two permanent magnets 51 and 51 adjacent to each other are provided such that magnetic poles having different polarities are in contact with each other. Further, in the circumferential direction of the magnetizing mold 43, the two permanent magnets 51, 51 existing on both sides of the magnetizing yoke 52 are provided so that the magnetic poles having the same polarity face each other via the magnetizing yoke 52. It has been.

  The magnetizing mold 43 is maintained in the state accommodated in the case 41. The magnetizing mold 43 may be fixed inside the case 41. The inner diameter of the magnetizing mold 43 is set slightly larger than the outer diameter of the rotor core 12. A space surrounded by the inner peripheral surface of the magnetizing mold 43 functions as a magnetized space 53 in which the rotor core 12 is accommodated. The height of the magnetized space 53 (permanent magnet 51, magnetized yoke 52) in the axial direction is set to be approximately the same as or slightly higher than the height of the rotor core 12 in the axial direction.

<Method for manufacturing rotor core>
Next, a method for manufacturing the embedded magnet type rotor will be described. The rotor core 12 is manufactured in advance by stacking a plurality of punched plates obtained by punching.

[1. Magnetization preparation process]
When manufacturing the rotor 11, first, the rotor core 12 is attached to the magnetizing device 23. Specifically, the rotor core 12 is inserted into the magnetizing space 53 of the magnetizing mold 43 from above with the key groove 14 a of the rotor core 12 and the key 45 a of the connecting shaft 45 aligned. As the rotor core 12 is inserted into the magnetized space 53, the connecting shaft 45 is inserted into the insertion hole 14 of the rotor core 12 and the key 45a is inserted into the key groove 14a from below. When the rotor core 12 is inserted into the magnetized space 53 to the position where it is placed on the inner bottom surface of the case 41, the attachment of the rotor core 12 to the magnetizing device 23 is completed. In the circumferential direction of the rotor core 12, the key 45 a engages with the key groove 14 a, so that the connecting shaft 45 can rotate integrally with the rotor core 12.

In the state where the rotor core 12 is attached to the magnetizing device 23, the positional relationship in the circumferential direction between the rotor core 12 and the magnetizing mold 43 is as follows.
As shown in FIG. 3, the inner part of the V shape of the magnet hole 15 faces the inner peripheral part of the magnetized yoke 52. Further, the boundary portion between the two magnet holes 15 and 15 adjacent to each other in the circumferential direction of the rotor core 12 is an inner circumferential portion of the permanent magnet 51 (more precisely, the two permanent magnets 51 and 51 that are in contact with each other in the circumferential direction). It faces the boundary part. The rotor core 12 is maintained in a state where it is placed in a magnetic field emitted from the magnetizing mold 43 (each permanent magnet 51) existing around the rotor core 12.

[2. Injection molding simultaneous magnetization process]
Next, a high-temperature magnet material 36 having fluidity is injected into each magnet hole 15 of the rotor core 12 through the injection device 22. A magnetic field emitted from the magnetizing mold 43 existing around the rotor core 12 is always applied to each magnet hole 15. For this reason, the high-temperature magnet material 36 having fluidity is filled in each magnet hole 15 while being magnetized. The rotor core 12 is heated by the heat of the high-temperature magnet material 36 being transmitted.

  As indicated by arrows in FIG. 3, a magnetic flux φ <b> 1 emitted from the magnetizing mold 43 (permanent magnet 51) is applied to the magnet material 36 filled in each magnet hole 15 of the rotor core 12. Magnetic flux φ1 passes through in the order of “magnetization yoke 52 adjacent to N pole of permanent magnet 51 → rotor core 12 → magnet material 36 → rotor core 12 → magnetization yoke 52 adjacent to S pole of permanent magnet 51”. Thereby, a magnetic path in the direction from the outside of the V shape toward the inside or a magnetic path from the inside to the outside of the V shape is formed in the magnet material 36.

  As shown in FIG. 4, the magnetic material 36 filled in the magnet hole 15 of the rotor core 12 is formed so that the inner portion of the V shape becomes an N pole, or the V shape is formed. The inner part is magnetized so as to be an S pole. Thereby, the magnet material 36 has a function as the permanent magnet 13.

  In FIG. 4, the polarity (N, S) of the magnetic field applied to each magnet material 36 is attached to each magnetized yoke 52 for convenience. A letter “N” is given to the magnetized yoke 52 through which the magnetic flux φ1 toward the rotor core 12 (the magnetic flux φ1 going from the inside to the outside of the V shape of the magnet material 36) passes. The magnetized yoke 52 through which the magnetic flux φ1 coming out of the rotor core 12 (magnetic flux φ1 going from the outside of the V shape of the magnet material 36 to the inside) passes is marked with the letter “S”. When an N pole magnetic field is applied to the V-shaped inner portion, the polarity of the V-shaped inner portion of the magnet material 36 is the S pole. When an S-pole magnetic field is applied to the V-shaped inner portion, the polarity of the V-shaped inner portion of the magnet material 36 is N-pole. Incidentally, although illustration is omitted, the outer portion of the magnet material 36 at V is magnetized so as to have a polarity opposite to the polarity of the inner portion of the V-shape.

  Thus, in the manufacturing method of the rotor 11 using the manufacturing apparatus 21, the step of injecting the magnet material 36 into each magnet hole 15 of the rotor core 12, and the step of magnetizing the magnet material 36 filled in each magnet hole 15, Are performed almost simultaneously.

[3. Stabilization process]
Next, a process for stabilizing the magnetic characteristics of the permanent magnet 13 is performed. That is, after the magnet material 36 is solidified, the rotor core 12 is rotated by driving the motor 42. However, for a while after the magnet material 36 is solidified, the temperature of the magnet material 36 (permanent magnet 13) is lower than the temperature at the time of injection, but is expected to be at a certain high temperature, for example, at least when the permanent magnet 13 is used. Is maintained at a maximum temperature or higher than the maximum temperature.

  As shown in FIG. 5, the control device 24 controls power feeding to the motor 42 so that the rotor core 12 rotates at least by an angle θ represented by the following expression (α). However, “n” is the number of magnetic poles of the rotor 11 (number of permanent magnets 13). “360 °” is an angle of one rotation of the rotor core 12.

θ = (1 / n) · 360 ° (α)
Here, since the number of magnetic poles of the rotor 11 is 10, the rotor core 12 is rotated by at least 36 °. In addition, you may rotate the rotor core 12 exceeding 36 degrees.

  For example, when the rotor core 12 is rotated by 36 °, the inner part of the V shape of each permanent magnet 13 (magnet hole 15) is opposed to the circumferential direction of the rotor core 12 during the magnetization process. It faces the inner peripheral portion of the magnetized yoke 52 adjacent to the magnetic yoke 52. For this reason, a magnetic field having a polarity opposite to that when magnetized, that is, a magnetic field in a direction opposite to the magnetization direction (magnetization direction) of each permanent magnet 13 is applied to each permanent magnet 13. The N-pole magnetic field is applied to the permanent magnet 51 (the V-shaped inner portion is the N-pole permanent magnet 51) to which the S-pole magnetic field is applied during magnetization. The S-pole magnetic field is applied to the permanent magnet 51 (the V-shaped inner portion is the S-pole permanent magnet 51) to which the N-pole magnetic field is applied during magnetization.

  As indicated by arrows in FIG. 5, the direction of the magnetic flux φ1 from the magnetizing yoke 52 and the direction (magnetization direction) of the magnetic flux φ2 from the permanent magnet 13 are opposite to each other. Therefore, a part of the magnetic flux φ <b> 2 from the permanent magnet 51 is canceled by the reverse magnetic flux φ <b> 1 from the magnetizing yoke 52. The permanent magnet 51 has a portion that is not easily demagnetized and a portion that is easily demagnetized. The portion that is easily demagnetized is demagnetized by applying a magnetic flux φ1 in the reverse direction of the magnetized yoke 52.

  Here, for the purpose of stabilizing demagnetization (so-called withering treatment) performed before use of the permanent magnet 13 for the purpose of suppressing and stabilizing the magnetic characteristics of the permanent magnet 13 with time, the following (A), (B There are two ways.

(A) A method of demagnetizing the permanent magnet 13 before use by heating the permanent magnet 13 to a maximum temperature expected when the permanent magnet 13 is used or a temperature higher than the maximum temperature.
(B) A method of demagnetizing the permanent magnet 13 before use by applying a reverse magnetic field to the permanent magnet 13.

  In this example, after the magnetization is completed, a reverse magnetic field is applied in a state where the temperature of the permanent magnet 13 is maintained at least at the highest temperature expected at the time of use or higher than the highest temperature. That is, (A) and (B) two stabilization demagnetizations are performed together.

  Whether or not the permanent magnet 13 is demagnetized during use depends on the reverse magnetic field and temperature applied to the permanent magnet 13. As long as only one of the temperature rise and the application of the reverse magnetic field is applied, even if the temperature rise and the application of the reverse magnetic field are combined, the resistance to demagnetization of the permanent magnet 13 is greatly reduced. There is a risk. (A), (B) By performing two stabilization demagnetizations, the magnetic characteristics of the permanent magnet 13 are stably maintained even under actual use conditions. By the way, the bond magnet has a weak coercive force compared to a sintered magnet because it contains a synthetic resin as a binder. For this reason, the manufacturing method of this example is suitable for a bonded magnet.

[4. Extraction process]
Next, the rotor core 12 in which the permanent magnets 13 are embedded is taken out from the magnetizing device 23 by a take-out device (not shown).

[5. Cooling process]
Finally, if the removed rotor core 12 is cooled by a cooling device (not shown), the manufacture of the rotor 11 is completed.

<Effect of Embodiment>
Therefore, according to the present embodiment, the following effects can be obtained.
(1) After the magnet material 15 is filled with the high-temperature magnet material 36 having fluidity and the magnetization is completed, the rotor core 12 (permanent magnet 13) in the high-temperature state is utilized by using the magnetic field emitted from the magnetizing mold 43. ) Is applied with a reverse magnetic field. This is equivalent to two stabilization demagnetization (a method of heating to a high temperature and a method of applying a reverse magnetic field) performed on the permanent magnet 13. For this reason, it is not necessary to separately provide special equipment for performing stabilization processing on the permanent magnet 13, such as a heating device for heating the rotor 11 and a magnetic field generator for applying a reverse magnetic field to the rotor 11.

  (2) Two stabilizing demagnetizations are performed on the permanent magnet 13 before use, so that the magnetic characteristics of the permanent magnet 13 are stabilized for a long time. That is, when the IPM motor is used, a magnetic field from a stator coil (not shown) is constantly applied to the permanent magnet 13 as a reverse magnetic field with respect to the permanent magnet 13, and demagnetization of the permanent magnet 13 due to the reverse magnetic field is suppressed. The For example, in a situation where the IPM motor is generating a large torque in an overload state, the permanent magnet 13 is heated with heat generated by a large current flowing through the stator coil. Is also suppressed. For this reason, during use of the IPM motor, a reduction in motor torque due to demagnetization of the permanent magnet 13 is suppressed. Since the motor characteristics hardly change, the motor characteristics are stabilized.

  (3) After the manufacture of the rotor 11 is completed, it is not necessary to heat the cooled rotor 11 again and to heat it to a high temperature or to apply a reverse magnetic field as a process for stabilizing demagnetization. For this reason, the manufacturing cycle time of the rotor 11 can be shortened. In other words, the productivity of the rotor 11 can be improved.

  (4) A motor 42 is employed as a rotary actuator that rotates the rotor core 12. Through the driving of the motor 42, the rotor core 12 can be rotated relative to the plurality of permanent magnets 51 (magnetic field generation sources).

  (5) When applying a reverse magnetic field to the permanent magnet 13, the control device 24 uses the position of the rotor core 12 when magnetizing the magnet material 36 as a reference and is at least 360 ° of one rotation angle of the rotor core 12. Then, the drive of the motor 42 is controlled so that the rotor core 12 rotates by an angle obtained by dividing by the number of magnetic poles of the rotor 11. According to this configuration, the magnetized permanent magnet 13 is rotated to a position corresponding to at least the magnetizing yoke 52 adjacent to the magnetizing yoke 52 that generates a magnetic field applied during magnetization. Since the plurality of magnetized yokes 52 alternately generate magnetic fields having different polarities along the circumferential direction of the rotor core 12, a magnetic field in a direction opposite to its magnetization direction is applied to the magnetized permanent magnet 13. The Thereby, the stabilization demagnetization before use of the magnetized permanent magnet 13 is performed suitably.

  (6) A reverse magnetic field is applied with the permanent magnet 13 solidified. That is, the rotor 11 is used in a state where the permanent magnet 13 is solidified, and the permanent magnet 13 is subjected to stabilization demagnetization before use in a state close to the actual use state. For this reason, demagnetization during use of the rotor 11 is suitably suppressed.

(7) A permanent magnet 51 that always generates a magnetic field is employed as the magnetic field generation source of the magnetizing mold 43. For this reason, the power supply device for generating a magnetic field is unnecessary.
(8) As an apparatus for filling the magnet material 36 into the magnet hole 15, the magnet material 36 is heated to have fluidity, and the magnet material 36 having fluidity is injected into the magnet hole 15 of the rotor core 12. A device 22 is employed. According to this configuration, the magnet material 36 is magnetized while being filled in the magnet hole 15 while being heated to such a degree that it has fluidity. That is, a stabilizing demagnetizing effect by heating the permanent magnet 13 is obtained. For this reason, the heating apparatus for exclusive use which heats the permanent magnet 13 anew is unnecessary. Further, it is not necessary to provide the magnetizing device 23 with a heating device for heating the permanent magnet 13 or the rotor core 12.

<Other embodiments>
In addition, you may implement this Embodiment as follows.
-Before attaching the rotor core 12 to the magnetizing mold 43, the rotor core 12 may be heated by a heating device (not shown) (preheating step). Thus, by injecting the rotor core 12 before injecting the melted magnet material 36, the magnet material 36 injected into the magnet hole 15 is easily maintained at a high temperature. By ensuring the fluidity of the magnet material 36, the magnet material 36 is easily filled in the magnet hole 15.

The two permanent magnets 51 and 51 that are in contact with each other in the circumferential direction of the magnetizing mold 43 may be provided as a single magnetizing permanent magnet.
In this example, when the rotor core 12 is rotated after the magnet material 36 is solidified, the solidification may be detected as follows, for example. That is, as shown by a two-dot chain line in FIG. 2, the temperature sensor 61 is provided in the vicinity of the rotor core 12, for example, on the inner wall of the case 41. At this time, the temperature sensor 61 is provided in the magnetizing mold 43 so as not to interfere with the interference. The control device 24 drives the motor 42 when the temperature of the rotor core 12 detected through the temperature sensor 61 falls to the threshold temperature after the injection of the magnet material 36 in the high temperature state is completed. The threshold temperature is determined by experiments or the like, and is set based on the temperature at which the molten magnet material 36 is solidified. The threshold temperature may be set to, for example, a maximum temperature expected during use or a temperature higher than the maximum temperature.

  According to this configuration, a reverse magnetic field is applied in a state where the magnet material 36 (permanent magnet 13) is solidified. That is, the rotor 11 is used in a state in which the permanent magnet 13 is solidified, and thus the permanent magnet 13 is stabilized and demagnetized before use in a state close to the actual use state. For this reason, demagnetization during actual use of the rotor 11 is suitably suppressed. When the threshold temperature is set to the highest temperature expected during use or higher than the highest temperature, the permanent magnet 13 is stabilized before use in a state close to the temperature during use of the rotor 11. Demagnetization is performed. For this reason, the demagnetization during use of the actual rotor 11 is suppressed more suitably.

  It is also possible to detect that the magnet material 36 has solidified without providing the temperature sensor 61. That is, as indicated by a two-dot chain line in FIG. For example, the control device 24 drives the motor 42 when the elapsed time after the injection of the molten magnet material 36 has reached the threshold time. The threshold time is determined by experiments or the like, and is set based on the time from when the injection of the magnet material 36 is completed until the temperature of the magnet material 36 is lowered to the extent that the magnet material 36 is solidified. . The threshold time may be set, for example, to a time from when the injection of the magnet material 36 is completed until the temperature of the magnet material 36 is reduced to an estimated temperature when the rotor is used.

  Also with this configuration, a reverse magnetic field is applied in a state where the magnet material 36 (permanent magnet 13) is solidified. That is, stabilization demagnetization before use is performed on the permanent magnet 13 in a state close to the actual use state. For this reason, demagnetization during actual use of the rotor 11 is suitably suppressed. Further, when the threshold time is set based on the time from when the magnet material 36 is filled in the magnet hole 15 until the temperature is lowered to the extent that the magnet material 36 is solidified, the permanent magnet 13 is kept close to the temperature when the rotor 11 is used. In contrast, stabilization demagnetization before use is performed. For this reason, the demagnetization during use of the actual rotor 11 is suppressed more suitably.

  In this example, the permanent magnet 51 is employed as the generation source of the magnetizing magnetic field. However, instead of the permanent magnet 51, an electromagnet (magnetizing yoke, coil) may be employed. As shown in FIG. 6, the magnetizing mold 43 has the same number of electromagnets 71 as the permanent magnets 13 embedded in the rotor 11. The electromagnet 71 has a core 72 and a coil 73 provided on the core 72. The coil 73 generates a magnetic field when energized. As a method of magnetizing the magnet material 36, any of a static magnetic field generation method that generates a high magnetic field and a pulse magnetic field generation method that instantaneously generates a high magnetic field can be employed. In the static magnetic field generation method, a direct current is supplied to the coil 73 to generate a static magnetic field in the electromagnet 71, and the magnet material 36 is magnetized by the static magnetic field. In the pulse magnetic field generation method, a pulse current is supplied to the coil 73 to generate a pulse magnetic field in the electromagnet 71, and the magnet material 36 is magnetized by the pulse magnetic field. When the pulse magnetic field generation method is employed, a magnetic field for magnetization is applied at an arbitrary timing from the start of filling of the magnet material 36 to the completion of filling. After the filling of the magnet material 36 is completed, a magnetic field for withering treatment (for demagnetization), that is, a reverse magnetic field in a direction opposite to the magnetic field for magnetization is applied. The pulse magnetic field need only be applied at least once. It is also possible to construct a magnetizing mold 43 in which the permanent magnet 51 and the electromagnet 71 are mixed. Moreover, it is also possible to employ only the coil 73 as the generation source of the magnetizing magnetic field.

  In this example, the motor 42 is used as a drive source for rotating the rotor core 12, but another rotary actuator such as a rotary solenoid may be used instead of the motor 42.

  In this example, the rotor core 12 is rotated relative to the magnetizing device 23 (more precisely, the magnetizing mold 43), but the magnetizing device 23 is rotated relative to the rotor core 12. Also good. In this case, for example, the rotating shaft 44 of the motor 42 is connected to the bottom of the case 41. Moreover, it is preferable to regulate the rotation of the rotor core 12 through a regulating mechanism (not shown). Further, both the rotor core 12 and the magnetizing device 23 may be rotated.

-Although the rotor core 12 of this example consists of an electromagnetic steel plate, you may use soft magnetic materials, such as electromagnetic soft iron, for example.
The permanent magnet 13 of this example has a V-shaped cross section perpendicular to the axial direction of the rotor core 12, but the shape of the permanent magnet 13 is not limited to this. For example, the permanent magnet 13 may have a cross-sectional shape that is orthogonal to the axial direction of the rotor core 12 that is linear or U-shaped.

The rotor 11 of this example has a 10-pole structure, but the number of magnetic poles of the rotor 11 is not particularly limited and may be changed as appropriate.
The magnetizing device 23 of this example has the case 41, but the magnetizing device 23 can be configured by omitting the case 41. For example, the magnetizing mold 43 may be supported by a support device (not shown). Further, only a portion corresponding to the bottom wall of the case 41 may be provided.

  In this example, the permanent magnet 13 is formed by injection into the magnet hole 15 of the rotor core 12, but the permanent magnet 13 can also be formed by compression molding. In this case, instead of the injection device 22, a compression molding device as a filling device is provided. Further, the magnetizing device 23 may be provided with a heating device for heating the magnetizing mold 43 or the rotor core 12 attached to the magnetizing die 43. When the rotor 11 is manufactured, first, the magnet material 36, which is a mixture of magnet powder before magnetization and synthetic resin (thermosetting resin), is mixed into the magnet hole of the rotor core 12 mounted on the magnetizing device 23. 15 and is molded by pressing the filled magnet material 36 with a plunger or the like. Thereafter, the magnet material 36 is cured by heating the rotor core 12 through a heating device. And after magnet material 36 (permanent magnet 13) is magnetized, rotor core 12 is rotated and a reverse magnetic field is applied. In this way, even when the compression molding method is employed, the same magnetizing device 23 can be used to perform both heating and stabilization demagnetization before use by application of a reverse magnetic field. Further, it is not necessary to separately provide a dedicated device that generates at least a reverse magnetic field.

  DESCRIPTION OF SYMBOLS 11 ... Rotor, 12 ... Rotor core, 13 ... Permanent magnet (bonded magnet), 15 ... Magnet hole, 21 ... Manufacturing apparatus, 22 ... Injection apparatus (filling apparatus), 23 ... Magnetizing apparatus, 24 ... Control apparatus, 36 ... Magnet Material: 41 ... Case, 42 ... Motor (drive source, rotary actuator), 45 ... connecting shaft, 51 ... permanent magnet (magnetic field generation source), 52 ... magnetization yoke, 73 ... coil (magnetic field generation source), 61 ... temperature Sensor, 62 ... counter.

Claims (9)

In an apparatus for manufacturing an embedded magnet type rotor in which a plurality of magnet holes provided in a core are each embedded with a bonded magnet, which is a kind of permanent magnet,
A magnetizing device that alternately generates magnetic fields of different polarities along the circumferential direction of the core;
A filling device for filling the magnet hole of the core with a magnet material;
The magnetic field is applied as a reverse magnetic field, which is a magnetic field opposite to the magnetization direction of the bond magnet, to the bond magnet obtained by magnetizing the magnet material filled in the magnet hole through application of the magnetic field. And a drive source for rotating the core and the magnetizing device relative to each other up to a position where the embedded magnet rotor is manufactured. In the manufacturing apparatus of the interior magnet type rotor according to claim 1,
The magnetizing device has a plurality of magnetic field generation sources that generate the magnetic field around the core,
The drive source is an apparatus for manufacturing an embedded magnet rotor that is a rotary actuator coupled to the core. In the manufacturing apparatus of the interior magnet type rotor according to claim 2,
When a reverse magnetic field is applied to the bond magnet, at least 360 °, which is an angle of one rotation of the core, is divided by the number of magnetic poles of the rotor with reference to the position of the core when the magnet material is magnetized. An apparatus for manufacturing an embedded magnet type rotor having a control device for controlling the drive of the rotary actuator so that the core rotates by an angle obtained thereby. In the manufacturing apparatus of the interior magnet type rotor according to claim 3,
A temperature sensor for detecting the temperature of the core;
When the magnet is heated to such an extent that the magnet material has fluidity, the temperature of the core detected through the temperature sensor is set to a temperature at which the magnet material having fluidity is solidified. An apparatus for manufacturing an embedded magnet type rotor that rotates the core through the rotary actuator when the temperature is lowered to a threshold temperature set on the basis of the threshold temperature. In the manufacturing apparatus of the interior magnet type rotor according to claim 3,
The control device includes a counter that measures an elapsed time after the magnet material is filled in the magnet hole,
When the control device is heated to such an extent that the magnet material has fluidity, the elapsed time detected through the counter decreases to a temperature at which the fluid material can be solidified. An apparatus for manufacturing an embedded magnet type rotor that rotates the core through the rotary actuator when a threshold time set based on the time required for the rotation is reached. In the manufacturing apparatus of the interior magnet type rotor according to claim 4 or 5,
The temperature at which the magnet material having fluidity is solidified is set based on the temperature at the time of use of the rotor. In the manufacturing apparatus of the interior magnet type rotor according to any one of claims 2 to 6,
The magnetic field generation source is a permanent magnet type rotor manufacturing apparatus that includes a permanent magnet that always generates the magnetic field or a coil that generates the magnetic field when energized. In the manufacturing apparatus of the interior magnet type rotor according to any one of claims 1 to 7,
The filling device is an apparatus for manufacturing an embedded magnet type rotor that is an injection device that heats the magnet material to give fluidity and injects the magnet material having fluidity into the magnet hole of the core. In the manufacturing method of an embedded magnet type rotor in which a plurality of magnet holes provided in the core are each embedded with a bonded magnet, which is a kind of permanent magnet,
A first step of attaching the core to a magnetizing device that alternately generates magnetic fields having different polarities along the circumferential direction of the core;
A second step of filling the core magnet hole with a magnet material;
The magnetic field is applied as a reverse magnetic field, which is a magnetic field opposite to the magnetization direction of the bond magnet, to the bond magnet obtained by magnetizing the magnet material filled in the magnet hole through application of the magnetic field. A third step of rotating the core and the magnetizing device relative to each other up to a position where the core is positioned.