JP6060376B2 - Self-starting permanent magnet synchronous motor and air blower equipped with the same - Google Patents

Description

  The present invention mainly relates to a self-starting permanent magnet synchronous motor and a blower for driving a ventilator such as a pipe fan or a general ventilator, a cooling fan for incorporating a device, or the like.

  Conventionally, a self-starting permanent magnet synchronous motor of this type has a configuration disclosed in Patent Document 1.

  The self-starting permanent magnet synchronous motor will be described below with reference to FIGS.

  As shown in FIGS. 8 to 9, the self-starting permanent magnet synchronous motor 101 includes a rotating shaft 102, a rotor 103 that is integrated with the outer periphery of the rotating shaft 102 and is rotatably held, and the rotor 103. The outer periphery is constituted by a stator 105 in which an armature winding 104 is wound in close proximity to the rotor 103 in a non-contact manner.

  The rotor 103 of the self-starting permanent magnet synchronous motor includes a laminated iron core 107, a starting squirrel cage conductor 110, and a permanent magnet 111 embedded in the starting squirrel cage conductor 110. Forming. The laminated iron core 107 is formed by laminating a circular rotor core to a predetermined thickness in the axial direction. The starting cage conductor 110 is formed by integrally molding a plurality of conductor bars 108 formed near the outer diameter of the rotor 103 and end rings 109 provided at both ends of the conductor bars 108 by aluminum die casting. The permanent magnet 111 is embedded in the starting cage conductor 110 on the inner diameter side of the conductor bar 108.

  The rotor core of the rotor 103 includes a plurality of rotor slots 112 for forming the conductor bars 108 near the outer periphery of the rotor 103 and a permanent magnet 111 embedded in the inner diameter side of the rotor slot 112. A slit 113 and a circular shaft hole 114 for press-fitting the rotating shaft 102 are formed.

  Therefore, a cylindrical shaft hole 114 for press-fitting the rotating shaft 102 is formed at the center of the rotor 103. The rotor 103 is configured to be rotatable by press-fitting and integrating the rotating shaft 102.

JP 2001-86670 A

  The self-starting permanent magnet synchronous motor 101 operates as an induction motor by the starting squirrel-cage conductor 110 of the rotor 103 at the time of starting. When the motor is accelerated to near the synchronous speed, the rotor magnetic pole of the permanent magnet 111 embedded in the rotor 103 is drawn into the synchronous magnetic field generated by the armature winding 104 and is operated as a synchronous machine. .

  Such a conventional self-starting permanent magnet synchronous motor 101 reduces the resistance value of the starting squirrel-cage conductor 110 of the rotor 103 to reduce the rotational speed at the maximum torque when operating as an induction motor. Make it high. In addition, the maximum torque is increased so that the synchronous pull-in is smoothly performed.

  However, the rotor core of the rotor 103 of the self-starting permanent magnet synchronous motor 101 includes a rotor slot 112 for forming the conductor bar 108, a slit 113 for embedding the permanent magnet 111, and the rotating shaft 102. The shaft hole 114 is used for press-fitting. Therefore, the rotor core is deformed when the rotary shaft 102 is press-fitted into a cylindrical shaft hole 114 formed at the center of the rotor 103. Due to the deformation of the rotor core, the stress of the starting squirrel-cage conductor 110 is increased to cause distortion. For this reason, when the conductor resistance value increases, the torque characteristics may decrease, which may cause a decrease in synchronous pullability.

  Therefore, the present invention solves the above-described conventional problems, and smooth synchronous pull-in by reducing the deformation of the rotor core that occurs when the rotary shaft is press-fitted into the rotor of the self-starting permanent magnet synchronous motor. It is an object of the present invention to provide a self-starting permanent magnet synchronous motor having the characteristics.

In order to achieve this object, the self-starting permanent magnet synchronous motor of the present invention is
A rotation axis;
A rotor integrated with the outer periphery of the rotating shaft and rotatably held;
On the outer periphery of the rotor, there is a stator that is arranged close to the rotor without contact,
The rotor is
A cylindrical laminated core formed by laminating a circular rotor core in the axial direction up to a predetermined thickness; and
A starting squirrel-cage conductor in which a plurality of conductor bars formed near the outer diameter of the rotor and end rings provided at both ends of the conductor bars are integrally formed by aluminum die casting;
It is composed of a permanent magnet embedded on the inner diameter side of this conductor bar,
The rotor core is
A slit for embedding at least a pair of permanent magnets symmetrically with respect to a predetermined diameter;
Having an elliptical shaft hole in the center of the rotor core;
The elliptical shaft hole is
The major axis of the ellipse is arranged in parallel with the diameter,
This achieves the intended purpose.

  According to the present invention, the rotating shaft, the rotor integrated with the outer periphery of the rotating shaft and rotatably held, and the stator disposed in close proximity to the outer periphery of the rotor without contact with the rotor. And the rotor includes a cylindrical laminated core formed by laminating a circular rotor core in the axial direction up to a predetermined thickness, a plurality of conductor bars formed near the outer diameter of the rotor, and the conductor It is composed of a starting squirrel-cage conductor integrally molded by aluminum die casting with end rings provided at both ends of the bar, and a permanent magnet embedded on the inner diameter side of the conductor bar, and the rotor core is composed of at least a pair of permanent magnets And an elliptical axial hole in the center of the rotor core, and the elliptical axial hole has a major axis of the ellipse parallel to the diameter. Configuration of self-starting permanent magnet synchronous motor That.

As a result, deformation of the rotor core that occurs when the rotary shaft is press-fitted into the rotor of the self-starting permanent magnet synchronous motor is mitigated. Therefore, the stress generated in the starting squirrel-cage conductor is reduced, and an increase in the conductor resistance value can be suppressed. As a result, it is possible to obtain an effect that a self-starting permanent magnet synchronous motor having a smooth synchronous pull-in property can be provided.

Sectional drawing which shows the installation state of the ventilator which carries an axial-flow fan An exploded perspective view showing a configuration of a self-starting permanent magnet synchronous motor Exploded perspective view showing the configuration of the rotor of the self-starting permanent magnet synchronous motor A graph showing the rotational speed-torque characteristics of a self-starting permanent magnet synchronous motor mounted on an axial blower (A) Plan view of a rotor core of a conventional self-starting permanent magnet synchronous motor, (B) Plan view showing deformation of the rotor core that occurs when a rotary shaft is press-fitted 1A is a plan view of a rotor core of a self-starting permanent magnet synchronous motor according to Embodiment 1 of the present invention, and FIG. 3B is a plan view showing deformation of the rotor core that occurs when a rotary shaft is press-fitted. (A) Plan view of rotor core of self-starting permanent magnet synchronous motor in Embodiment 2 of the present invention, (B) Plan view showing deformation of rotor core that occurs when rotary shaft is press-fitted A diagram showing a conventional self-starting permanent magnet synchronous motor Plan view of the rotor core of a conventional self-starting permanent magnet synchronous motor

The self-starting permanent magnet synchronous motor according to claim 1 of the present invention includes a rotating shaft, a rotor integrated with the outer periphery of the rotating shaft and rotatably held, and the rotor on the outer periphery of the rotor. The rotor is arranged in a non-contact manner, and the rotor includes a cylindrical laminated core formed by laminating a circular rotor core to a predetermined thickness in the axial direction, and a rotor outer diameter. A plurality of conductor bars formed in the vicinity and end rings provided at both ends of the conductor bar are integrally formed by aluminum die casting, and a starting cage conductor, and a permanent magnet embedded on the inner diameter side from the conductor bar, The rotor core has a slit for embedding at least a pair of permanent magnets in line symmetry with respect to a predetermined diameter, and an elliptical shaft hole at the center of the rotor core, and the elliptical shaft hole Place the major axis of the ellipse parallel to the diameter Configuration to.

  As a result, deformation of the rotor core that occurs when the rotary shaft is press-fitted into the rotor of the self-starting permanent magnet synchronous motor is mitigated. Therefore, the stress generated in the starting squirrel-cage conductor is reduced, and an increase in the conductor resistance value can be suppressed. As a result, it is possible to provide a self-starting permanent magnet synchronous motor having a smooth synchronous pull-in property.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
As shown in FIG. 1, the axial blower 1 includes a self-starting permanent magnet synchronous motor 2 and a propeller fan 4 attached to a rotating shaft 3 of the self-starting permanent magnet synchronous motor 2. The ventilator 5 incorporates an axial blower 1, sucks indoor air from the suction port by the axial blower 1, passes through the wall 6 of the building, and discharges it outdoors.

  As shown in FIG. 2, the self-starting permanent magnet synchronous motor 2 includes a rotor 7 and a stator 9 that are rotatably held. The rotor 7 is integrated with the outer periphery of the rotary shaft 3 made of carbon steel and is rotatably held. The stator 9 has an armature winding 8 wound around the outer periphery of the rotor 7 so as not to contact the rotor 7 and in close proximity.

  As shown in FIG. 3, the rotor 7 includes a cylindrical laminated core 11, a starting cage conductor 14 and a permanent magnet 15, and forms a rotor magnetic pole. The laminated iron core 11 is formed by laminating a circular rotor core 10 made of an electromagnetic steel plate to a predetermined thickness in the axial direction. The starting cage conductor 14 is formed by integrally molding a plurality of conductor bars 12 formed near the outer diameter of the rotor 7 and end rings 13 provided at both ends of the conductor bar 12 by aluminum die casting. The permanent magnet 15 is made of a rare earth magnet or the like, and is embedded on the inner diameter side of the conductor bar 12 provided on the starting cage conductor 14.

  Here, the characteristics of the self-starting permanent magnet synchronous motor 2 mounted on the axial blower 1 will be described.

FIG. 4 is a graph showing the rotational speed-torque characteristics of the self-starting permanent magnet synchronous motor 2.
In FIG. 4, the horizontal axis represents the number of rotations of the self-starting permanent magnet synchronous motor 2, and the vertical axis represents the torque. At start-up, a commercial AC power supply is applied to the armature winding 8 of the stator 9, whereby a current flows through the armature winding 8 of the stator 9. A rotating magnetic field is generated from the armature winding 8 of the stator 9 by the magnetomotive force due to the current. Then, the rotor 7 is started as an induction motor by the interaction with the induced current generated in the starting cage conductor 14 of the rotor 7 (region A in FIG. 4).

  On the other hand, when the rotor 7 is accelerated to near the synchronous speed of the rotating magnetic field of the stator 9, the rotor magnetic pole by the permanent magnet 15 of the rotor 7 rotates at the synchronous speed that the armature winding 8 of the stator 9 creates. It is drawn into the magnetic field and operates as a synchronous machine (region B in FIG. 4).

  Therefore, the self-starting permanent magnet synchronous motor can be smoothly pulled in synchronously by increasing the rotation speed at the maximum torque and increasing the maximum torque value in the region A of FIG. 4 operating as an induction motor.

  In the region A of FIG. 4, in order to achieve the desired rotational speed-torque characteristics, the resistance value of the starting cage conductor 14 as a whole may be reduced. That is, while increasing the cross-sectional area of the conductor bar 12 and the end ring 13 and forming the starting cage conductor 14 by aluminum die casting, the resistance value of the starting cage conductor 14 as a whole is sufficiently filled with aluminum. Becomes smaller.

  Next, the deformation | transformation of the rotor core 10 produced when the rotating shaft 3 is press-fitted in the rotor core 10 and the rotor 7 is demonstrated.

  5 to 7 show the deformation of the rotor core that occurs when the conventional rotor core and the rotary shaft are press-fitted.

  A conventional rotor core 10A shown in FIG. 5 has a plurality of rotor slots 16 for forming the conductor bars 12 near the outer periphery, and a pair symmetrically with respect to the diameter 17 on the inner diameter side of the rotor slots 16. The permanent magnet 15 is embedded with a slit 18A and a substantially circular shaft hole 19A for press-fitting the rotary shaft 3.

  5A shows the rotor core 10A before the rotary shaft 3 is press-fitted, and FIG. 5B shows the deformation of the rotor core 10A when the rotary shaft 3 is press-fitted into the circular shaft hole 19A. Indicates.

  As shown in FIG. 5 (B), when the rotary shaft 3 made of carbon steel is pressed into the shaft hole 19A of the rotor core 10A made of electromagnetic steel, the rotor core 10A having a lower elastic modulus than the rotary shaft 3 As shown by the broken line of the hole 19A, it tries to deform uniformly in the outer diameter direction. However, since the permanent magnet 15 different from the elastic modulus of the rotor core 10A is embedded in the slit 18A of the rotor core 10A, deformation occurs in the direction of the diameter 17 as shown by the broken line in FIG. The deformation extends to a plurality of rotor slots 16 for forming the conductor bar 12 near the outer periphery of the rotor core 10. Then, the stress of the aluminum conductor bar 12 formed in the rotor slot 16 having a lower elastic modulus than the rotor core 10 is increased, and the conductor bar 12 is distorted and deformed. As a result, the overall resistance value of the starting cage conductor 14 increases.

  Therefore, in the region A of FIG. 4, since the rotational speed at the maximum torque is reduced and the value of the maximum torque is reduced, the synchronous pull-in property is reduced.

  FIG. 6 shows the deformation of the rotor core that occurs when the rotor core and the rotating shaft are press-fitted in the first embodiment of the present invention.

  In the rotor core 10B according to the first embodiment of the present invention shown in FIG. 6, the shaft hole 19B for press-fitting the rotary shaft 3 into the conventional rotor core 10A has an elliptical shape, and is on the diameter 17. The major axis of the ellipse is arranged.

  FIG. 6A shows the rotor core 10B before press-fitting the rotary shaft 3, and shows deformation of the rotor core 10B when the rotary shaft 3 is press-fitted into an elliptical shaft hole 19B.

  As shown in FIG. 6B, when the rotary shaft 3 made of carbon steel is press-fitted into the elliptical shaft hole 19B of the rotor core 10B made of an electromagnetic steel plate, the rotor core 10 having a lower elastic modulus than the rotary shaft 3 is used. However, as shown by the broken line of the shaft hole 19B, it tends to deform in the outer diameter direction. Since the major axis of the elliptical shaft hole 19B is arranged in parallel with the diameter 17, the force applied in the direction of the diameter 17 is small, and it is difficult to deform in the direction of the diameter 17 compared to FIG. That is, because the major axis of the elliptical shaft hole 19B provided for press-fitting the rotating shaft 3 is arranged in parallel with the diameter 17, deformation of the rotor core 10B with respect to the press-fitting of the rotating shaft 3 is alleviated. .

With the above configuration, the stress generated in the starting cage conductor 14 made of aluminum is reduced,
An increase in the conductor resistance value can be suppressed. As a result, it is possible to provide a self-starting permanent magnet synchronous motor having a smooth synchronous pull-in property.

  In the present embodiment, the shape of the slit 18B for embedding the permanent magnet 15 has been described as a rectangular shape, but it may be in another shape such as an arc shape.

(Embodiment 2)
FIG. 7 is a diagram showing a rotor core 10C of the self-starting permanent magnet synchronous motor according to the second embodiment of the present invention.

  In this figure, the difference from Embodiment 1 (the rotor core 10B shown in FIG. 6) is that the slit 18C for embedding the permanent magnet 15 is divided into four or more on a substantially circular arc in line symmetry with a predetermined diameter 17. It is a point that is arranged.

  And the space | interval of adjacent slit 18C has taken the space | interval D1 formed in the part equivalent to the diameter 17 larger than the space | interval D2 of the slits 18C of another part.

  Also, the same components as those in FIG. 6 are denoted by the same reference numerals, and description thereof is omitted. Moreover, since it is the same also about the block diagram which shows the ventilation apparatus 5 which mounted the axial-flow fan 1 of FIG. 1, and the self-starting permanent magnet synchronous motor 2 of FIG. 2, the description is abbreviate | omitted.

  In this case, as described above, the rotation shaft 3 is press-fitted into the elliptical shaft hole 19C, thereby deforming the shaft hole 19C of the rotor core 10C. Slits 18C for embedding the permanent magnets 15 are arranged in four parts on a substantially arc. Therefore, the stress generated in the permanent magnet 15 is dispersed, and deformation generated in the direction of the diameter 17 can be further reduced.

Therefore, the stress generated in the starting squirrel-cage conductor 14 made of aluminum provided in the vicinity of the outer periphery of the rotor 7 is further reduced, and an increase in the conductor resistance value can be further suppressed. as a result,
It is possible to provide a self-starting permanent magnet synchronous motor having smoother pull-in property.

  Further, in the self-starting permanent magnet synchronous motor 2 of the present invention, the major axis of the elliptical shaft hole 19C for press-fitting the rotary shaft 3 provided in the rotor core 10C is arranged in parallel with the predetermined diameter 17. The deformation generated in the rotor core 10C can be reduced by press-fitting the rotary shaft 3 into the shaft hole 19C. And the stress which arises in the starting cage conductor 14 which consists of aluminum provided in the outer periphery vicinity of the rotor 7 reduces, and it can suppress the increase in a conductor resistance value. Therefore, it is possible to smoothly perform synchronous pull-in by increasing the rotation speed at the maximum torque during operation of the induction motor and increasing the maximum torque value.

  Moreover, since the space | interval D1 is taken larger than the space | interval D2, the force added to the direction orthogonal to the diameter 17 is prevented by the slit 18C. On the other hand, the force applied in the direction of the diameter 17 escapes in the outer peripheral direction by the interval D1, and the entire deformation is suppressed.

  In the self-starting permanent magnet synchronous motor according to the present invention, the shaft hole for rotating shaft press-fitting provided in the central portion of the rotor core has an elliptical shape, so that deformation of the rotor core during press-fitting of the rotating shaft is alleviated. Since the stress generated in the starting squirrel-cage conductor is reduced, a change in the conductor resistance can be suppressed and the synchronous pull-in property is improved. It is useful as a self-starting permanent magnet synchronous motor and a blower for driving a ventilation device such as a pipe fan or a general type ventilation fan, or a cooling fan for incorporating a device.

DESCRIPTION OF SYMBOLS 1 Axial-flow fan 2 Self-starting permanent magnet synchronous motor 3 Rotating shaft 4 Propeller fan 5 Ventilator 6 Wall 7 Rotor 8 Armature winding 9 Stator 10 Rotor core 10A, 10B, 10C Rotor core 11 Laminated core 12 Conductor bar 13 End ring 14 Starting cage conductor 15 Permanent magnet 16 Rotor slot 17 Diameter 18 Slit 18A, 18B, 18C Slit 19 Shaft hole 19A, 19B, 19C Shaft hole

Claims (4)

A rotation axis;
A rotor integrated with the outer periphery of the rotating shaft and rotatably held;
On the outer periphery of this rotor,
This rotor has a stator that is placed in close proximity without contact,
The rotor is
A cylindrical laminated core formed by laminating a circular rotor core in the axial direction up to a predetermined thickness; and
A starting squirrel-cage conductor in which a plurality of conductor bars formed near the outer diameter of the rotor and end rings provided at both ends of the conductor bars are integrally formed by aluminum die casting;
It is composed of permanent magnets embedded on the inner peripheral side of this conductor bar,
The rotor core is
A slit for embedding at least a pair of permanent magnets symmetrically with respect to a predetermined diameter;
Having an elliptical shaft hole in the center of the rotor core;
The elliptical shaft hole is
A self-starting permanent magnet synchronous motor in which an ellipse major axis is arranged in parallel with the diameter. The self-starting permanent magnet synchronous motor according to claim 1, wherein the slits are arranged in an even number of four or more in line symmetry with the diameter. The self-starting permanent magnet synchronous motor according to claim 2, wherein an interval between the adjacent slits is set such that an interval between the diameter portions is larger than other intervals. A blower equipped with the self-starting permanent magnet synchronous motor according to claim 1.

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