JP2015231253A - Magnet and dynamo-electric machine including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnet capable of enhancing demagnetization durability by converging magnetic flux efficiently, when employing a reverse radial orientation, in a surface permanent magnet field motor (SPM), and to provide a dynamo-electric machine including the same.SOLUTION: A magnet 32 disposed in the circumferential direction of a rotor 3 is oriented so that the magnetic flux is converged to an arbitrary focal point O set on the radial outside of a rotor core 31 on a magnetic pole center line L, and the opposite corners, i.e., the opposite ends of the rotor core 31 in the magnet, located on the radial outside thereof are chamfered.

Description

  The present invention relates to a magnet and a rotating electrical machine including the magnet, and more particularly to a magnet that can be effectively applied to a surface permanent magnet field rotating electrical machine (SPM) and a rotating electrical machine including the magnet.

As one of rotating electric machines, a permanent magnet type synchronous motor using a permanent magnet as a field is generally known.
In such a rotating electrical machine, a permanent magnet is disposed on the rotor, and the rotor is configured to rotate by interaction with a magnetic field disposed on a stator that is installed so as to surround the rotor. Yes.
As a method for incorporating a permanent magnet into a rotor, types such as a surface magnet type (SPM) and an embedded magnet type (IPM) are known.
As described above, in a motor using a permanent magnet, it is necessary to reduce the amount of magnet used in order to reduce the cost. For this reason, it is necessary to efficiently generate a magnetic flux in the magnet.
For example, as shown in FIG. 4 (c), various other methods have been proposed for obtaining a magnetic force from a permanent magnet or a technique for giving a magnet a parallel orientation (for example, Patent Document 1). reference).

Patent Document 1 discloses a technique regarding a rotor of a rotating electrical machine.
The plurality of magnets in the technology are fixed to the outer peripheral surface of the rotor core so that N poles and S poles are alternately arranged.
And each magnet is set as the structure which the magnetic flux which inclines so that the cross section orthogonal to the axis line of a rotating shaft may approach the magnetic pole center line may be set to radial direction outer side.
That is, each magnet is configured to generate a radial magnetic flux that passes through one point on the magnetic pole center line disposed outside the magnet.
Therefore, it is possible to provide a rotor of a rotating electrical machine with good characteristics.

JP 2009-124852 A

As described above, according to the technique described in Patent Document 1, it is possible to efficiently collect the magnetic flux on the teeth of the stator.
However, in order to collect the magnetic flux more efficiently, it is more efficient to concentrate the magnetic flux orientation at an arbitrary point with respect to the magnetic pole width, and such a method has also been proposed.
For example, in the SPM rotor, there are various known methods for increasing the effective magnetic flux and increasing the generated torque by concentrating the magnetic flux orientation at an arbitrary point with respect to the magnetic pole width. As these methods, for example, There are polar anisotropic orientation (see FIG. 4A), Halbach orientation (see FIG. 4B), reverse radial orientation (see FIG. 4D, Patent Document 1), and the like.

Among these, reverse radial alignment is mentioned as the cheapest and easiest method.
In this reverse radial orientation, the structure and shape of the magnet may remain the arc shape used in a normal SPM rotor, and it can be manufactured simply by changing the mold configuration at the time of molding, and it can be mounted relatively easily. This is advantageous in terms of cost.
On the other hand, there is a lower limit on the magnet thickness in the polar anisotropic orientation, and the Halbach orientation has a problem that the assembly cost increases because a large number of magnets are required.
However, there are various problems in adopting this reverse radial orientation.

In other words, the shape of a magnet used in a normal SPM motor is generally an arc shape or a tile shape. Therefore, when reverse radial orientation is applied to the shape, both ends (particularly corners) of the permanent magnet are used. There is a problem that the magnet thickness in the orientation direction becomes extremely thin.
For this reason, since the retention of orientation against an external magnetic field or temperature change is deteriorated and the demagnetization resistance is lowered, it is necessary to solve the problem.

  An object of the present invention is to solve the above-described problems, and in adopting reverse radial orientation in a surface permanent magnet field motor (SPM), the magnetic flux is efficiently converged and the demagnetization resistance is improved. An object of the present invention is to provide a magnet that can be used and a rotating electric machine including the magnet.

  According to the magnet of the present invention, the above-described problem is a magnet disposed in the circumferential direction of the rotor core, and the magnet is set on the magnetic pole center line and on the radially outer side of the rotor core. The magnetic cores are oriented so that the magnetic flux is focused on an arbitrary concentrating point, and both corners of the magnet in the circumferential direction of the rotor core, which are located on the radially outer side of the rotor core, are This is solved by having a chamfered chamfered portion.

As described above, in the present invention, the magnetic flux is oriented so that the magnetic flux is focused on an arbitrary focusing point set on the magnetic pole center line and outside the rotor core in the radial direction. Although it can be increased and the size of the magnetic circuit part can be reduced, both corners of the rotor core in the circumferential direction and chamfered at both corners located radially outside the rotor core Therefore, the magnetic flux can be efficiently focused on the focusing point.
Therefore, it is not necessary to extremely reduce the magnet thickness in the orientation direction at both ends of the magnet, and the magnetic flux can be efficiently focused.

Further, at this time, as described in claim 2, it is preferable that the chamfered portion is chamfered at an angle along a reverse radial orientation vector from the whole magnet toward the focusing point.
Such a configuration is preferable because the angle of the chamfered portion and the angle of the orientation vector coincide with each other, so that the magnetic flux can be more efficiently concentrated.

Furthermore, at this time, specifically, as described in claim 3, the magnet may be a ferrite magnet or a neo-geo magnet.
More specifically, as described in claim 4, the magnet may be configured to be used in a continuous pole type rotor and to form one magnetic pole.
Further, the rotating electrical machine according to the present invention is arranged in the circumferential direction of the outer surface of the rotor core, the shaft serving as the rotation center axis, the rotor core fixed to the shaft and supported rotatably. A rotor provided with the magnet according to any one of claims 1 to 4, and a rotor disposed so as to cover an outer surface of the rotor. And at least a stator that generates a magnetic field.

According to the present invention, since both end portions in the circumferential direction of the rotor core are chamfered at both corners located on the outer side in the radial direction of the rotor core, the magnetic flux can be efficiently focused on the focusing point, Therefore, it is not necessary to extremely reduce the magnet thickness in the orientation direction at both ends of the magnet.
For this reason, the orientation retention with respect to an external magnetic field and a temperature change is improved, and the demagnetization resistance is also improved.
Furthermore, by making the chamfer angle along the orientation vector, the magnetic flux can be more efficiently focused on the converging point, and thus the above effect can be enhanced.
As described above, according to the present invention, in adopting the reverse radial orientation in the surface permanent magnet field motor (SPM), the magnetic flux can be efficiently converged and the demagnetization resistance can be improved.

It is explanatory drawing which shows the radial direction cross section of the rotary electric machine which concerns on one Embodiment of this invention. It is explanatory drawing which shows the orientation direction of the magnet which concerns on one Embodiment of this invention. It is a figure which shows the said equivalent location which concerns on the X section enlarged view of FIG. 2, and a modification. It is explanatory drawing which shows a prior art example.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Note that the configuration described below does not limit the present invention and can be variously modified within the scope of the gist of the present invention.
In the present embodiment, in adopting reverse radial orientation in a surface permanent magnet field motor (SPM), a magnet capable of efficiently converging a magnetic flux and improving demagnetization resistance is adopted. Related to the motor.

1 to 3 show an embodiment of the present invention. FIG. 1 is an explanatory view showing a radial section of a rotating electrical machine, FIG. 2 is an explanatory view showing an orientation direction of a magnet, and FIG. It is a figure which shows the said equivalent location which concerns on the X section enlarged view of, and a modification.
FIG. 4 is an explanatory view showing a conventional example.

First, an example of the configuration of a motor M (corresponding to “rotary electric machine”) on which the magnet 32 according to the present embodiment is mounted will be briefly described with reference to FIG.
The motor M is a surface permanent magnet field motor (SPM motor), and a plurality of magnets 32 are disposed on the side surface of the rotor 3.
The motor M includes a shaft 1 serving as an output shaft, a stator 2 (corresponding to “stator”), and a rotor 3 (corresponding to “rotor”).

The stator 2 is formed in a substantially cylindrical shape. Although not shown, the stator 2 includes a plurality of teeth extending radially inward and windings wound around the teeth.
Power is supplied to a winding constituting the stator 2 from a power supply device (not shown), whereby a rotating magnetic field is generated in the stator 2, and the rotor 3 is rotated by the rotating magnetic field.

A shaft 1 penetrating in the axial direction is fixed at the center of the rotor 3, and the rotor 3 is rotatably supported inside the stator 2.
The rotor 3 includes a substantially cylindrical rotor core 31 (corresponding to a “rotor core”) and a plurality of magnets 32 fixed to the outer peripheral side surface of the rotor core 31.
In this embodiment, ten magnets 32 having five N poles and five S poles are used, and the N poles and the S poles alternate along the circumferential direction of the outer peripheral side surface of the rotor core 31. It is arranged (projected) at equal intervals.
Thus, in this embodiment, the surface magnet type (SPM) rotor 3 is used.

The magnet 32 has a central portion in the circumferential direction of the rotor core 31 formed in a curved shape so as to follow the arc shape of the rotor 3, and the corners on the both ends in the circumferential direction of the magnet 32 and on the radially outer side are It is chamfered.
That is, the corner is an inclined surface (linear shape in a cross-sectional plan view).
The chamfered portion is hereinafter referred to as a “chamfered portion 32a”.
Further, the magnet 32 is formed so as to have reverse radial orientation.

With this configuration, when power is supplied from a power supply device (not shown), a rotating magnetic field is generated in the stator 2, and the rotor 3 rotates due to interaction with a plurality of magnets 32 incorporated in the rotor 3. To do.
This rotational force is output by the shaft 1.

Next, the magnet 32 will be described with reference to FIG. 2 and FIG.
As described above, the chamfered portions 32a and 32a are respectively formed at the corners on both ends in the circumferential direction of the magnet 32 and on the radially outer side.
And since the magnet 32 is formed so that it may become reverse radial orientation, it is approaching the magnetic pole center line L (a line along the radial direction of the rotor 3 and passing through the circumferential center of each magnet 32). An inclined magnetic flux is generated, and this magnetic flux is collected at a converging point O on the magnetic pole center line L (concentrated outward in the radial direction of the rotor core 31 on the magnetic pole center line L).

At this time, since the chamfered portions 32a and 32a are formed in the magnet 32, the magnetic flux can be efficiently collected at the concentrating point O as shown in FIG.
At this time, it is preferable that the chamfering angle of the chamfered portion 32 a matches the orientation angle of the magnet 32.
That is, it is preferable to set the chamfering angle according to the position of the converging point O (concentrating points O1 to O3) according to the orientation angle of the magnet 32.

As described above, since the magnet 32 has a shape for concentrating the magnetic flux at the converging point O, the shape of the surface magnetic flux becomes a shape close to a sine wave, so that distortion of the induced voltage can be reduced.
Further, since the angle formed by the magnetic flux vector at the circumferential end of the magnet 32 is increased by forming the chamfered portion 32a, the short-circuit magnetic flux between the poles is reduced and the effective interlinkage magnetic flux is increased.

Furthermore, by forming the chamfered portion 32a, it is possible to prevent the end of the magnet 32 from being cracked or chipped during assembly, and the amount of magnet is reduced, so that the inertia of the rotor 3 can be reduced.
In addition, as a kind of the magnet 32, what kind of thing may be used in the range which does not deviate from the meaning of this invention, However, A ferrite magnet and a neodymium magnet are used suitably.

Further, FIG. 3B shows an example of a continuous pole type rotor 3 as a modified example.
In the rotor 3 illustrated in FIG. 3B, a plurality of N-pole or S-pole magnets 32 are used, and salient poles 33 are disposed between the magnets 32 and 32.
As described above, as shown in FIG. 3B, even when the continuous pole type rotor 3 is employed as the rotor 3, the above configuration is effectively applied to the magnet 32 having one magnetic pole.

As described above, in the present embodiment, when adopting the reverse radial orientation, the effective magnetic flux is increased only by chamfering at both ends of the magnet 32 without forming the thickness in the orientation direction extremely thin. Can do.
Therefore, it is possible to maintain orientation against external temperature changes and ensure demagnetization resistance.

1 .. Shaft 2. Stator (stator) 3. Rotor (rotor)
31. Rotor core (rotor core),
32 .. Magnet, 32a ... Chamfer, 33 ... Salient pole,
L ... Magnetic pole center line, O ... Concentration point, M ... Motor (rotary electric machine)

Claims (5)

A magnet disposed in a circumferential direction of the rotor core,
The magnet is oriented so that the magnetic flux is focused on an arbitrary focusing point set on the magnetic pole center line and radially outside the rotor core. The magnet is characterized in that both corner portions located at both ends in the direction and located radially outside the rotor core are chamfered chamfered portions.   The magnet according to claim 1, wherein the chamfered portion is chamfered at an angle along a reverse radial orientation vector from the entire magnet toward the converging point.   The magnet according to claim 1, wherein the magnet is a ferrite magnet or a neo-geo magnet.   The magnet according to any one of claims 1 to 3, wherein the magnet is used in a continuous pole rotor and forms one magnetic pole. A shaft serving as a rotation center axis;
The rotor core fixed to the shaft and rotatably supported together, and the magnet according to any one of claims 1 to 4 disposed in a circumferential direction of the outer surface of the rotor core. A rotor with
A rotating electrical machine comprising at least a stator disposed so as to cover an outer surface of the rotor and generating a rotating magnetic field when power is supplied from a power supply device.

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