JPH06339241A - Permanent magnet type motor and manufacture thereof - Google Patents

Abstract

PURPOSE:To improve manufacturing properties of a permanent magnet and a rotor and to improve performance such as a driving efficiency, etc. CONSTITUTION:Permanent magnets 27 to be assembled in a rotor core 25 in a rotor 23 are formed in a circular-arc shape in section, and so disposed that protrusions 27a side are directed toward an inside in a rotor core 25. A size between an outer surface of a recess 27b of the magnets 27 and an outer periphery of the core 25 can be increased in the core 25 to obtain a mechanical strength of the part, and hence processing of the core 25 is facilitated. When materials of the magnets 27 are magnetized in a state that the materials to become the magnets 27 are assembled, the magnets 27 can be preferably magnetized to its ends.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet type motor having a rotor constructed by incorporating a plurality of permanent magnets inside a rotor core, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Recently, as a permanent magnet type motor, a motor having a structure shown in FIG. 5 has been developed as a motor having high torque and high efficiency. This product has the following configuration.

That is, the stator 1 has 24 slots S1 to S24 formed in the stator core 2 having an annular shape.
U-phase stator windings 1U, 2U, 3U, 4U, V-phase stator windings 1V, 2V, 3V, 4V, and W-phase stator windings 1W, 2W, 3W, 4W are inserted and arranged ( (See Figure 6)
Is configured.

On the other hand, in the rotor 3, the rotor core 5 is fitted and fixed to the rotary shaft 4, and the housing portion 6 formed in the rotor core 5 has four permanent magnets having an arc-shaped cross section. It is configured by inserting the magnet 7 from the axial direction and incorporating it, and is rotatably disposed inside the stator 1 with the inner peripheral portion of the stator core 2 and a predetermined gap 8 being present. Each of the permanent magnets 7 is arranged so that the convex portion 7a side faces the outside (air gap 8 side), and the four permanent magnets 7 are arranged so that the N poles and the S poles alternate in FIG. It is magnetized.

Here, when the rotor 3 is manufactured, as shown in FIG. 7, an arc-shaped magnet material 9 (for example, ferrite) which becomes the permanent magnet 7 is inserted into the housing portion 6 of the rotor core 5, In this state, the magnet material 9 is magnetized by the magnetizing device 10. Reference numeral 11 is an iron core of the magnetizing device 10, and 12 is a slot formed in the iron core 11. A coil (not shown) for passing a current for magnetizing is housed in the slot 11. .

The above-mentioned motor is adapted to be fed by a variable voltage variable frequency power source, a so-called inverter. Then, when the stator windings 1U to 4W of the stator 1 are energized with two phases for each phase of U, V, and W from the inverter in a predetermined order at 120 degrees (electrical angle). The rotor 3 is rotated by the magnetic attraction force and the repulsive force generated thereby.

[0007]

By the way, in the permanent magnet type motor having the above-mentioned structure, high torque and high efficiency can be obtained, but in the rotor core 5, the outer peripheral portion which covers the permanent magnet 7 and faces the air gap 8. Since it is necessary to make the dimension of 5a a magnetic optimum value determined by the strength of the permanent magnet 7 and the thickness of the permanent magnet 7, in order to obtain the dimensional accuracy of the outer peripheral portion 5a, the outer peripheral surface of the rotor core 5 is Need to be post-processed. In this case, since the dimension between the outer surface of the permanent magnet 7 and the outer peripheral surface of the rotor iron core 5 is small and it is necessary to perform processing in consideration of mechanical strength and the like, it takes a lot of time for processing and the work efficiency is high. Needs improvement.

In addition, in the above permanent magnet type motor, in order to insert the magnet material 9 which becomes the permanent magnet 7 into the housing portion 6 of the rotor core 5, the magnet material 9 requires a predetermined dimensional accuracy. Since the magnet material 9 has an arc shape, it is relatively easy to process for obtaining the dimensional accuracy and is excellent in cost.

However, in the state where the magnet material 9 is inserted into the housing portion 6 of the rotor core 5 as described above, the magnetizing device 10 is used.
When magnetizing the magnet material 9 by means of the magnet material 9 as shown in the magnetizing field by the magnetizing device 10 shown in FIG.
The magnetic flux 13a passes through in the radial direction of the magnet material 9 and can be magnetized well in the central portion of the magnetic material, that is, in the vicinity of the central portion of the pole. The magnet material 9 is distributed in the circumferential direction. Therefore, the magnetic flux near the end of the magnetized permanent magnet 7 has a small component toward the air gap 8, and there is a problem that sufficient magnetization cannot be performed near the end of the permanent magnet 7.

As described above, in the structure described above, the magnetic flux in the gap 8 generated from the permanent magnet 7 becomes insufficient, which causes a decrease in torque and a decrease in drive efficiency. In order to avoid such a decrease in performance, it may be considered that the permanent magnet 7 is magnetized by itself before being incorporated and the magnetized permanent magnet 7 is incorporated in the rotor core 5. However, with such a configuration, the time and effort for post-processing are further increased, work efficiency is significantly reduced, and the cost of the motor is further increased.

On the other hand, the rotor shown in FIG. 8 may be used as the rotor. The rotor 14 has a rotor core 15 fitted and fixed to a rotor shaft 4, and a housing portion 16 formed in the rotor core 15 has four permanent magnets 1 having a flat cross section.
7 is inserted from the axial direction and incorporated.

In the case of the rotor 14 having such a structure,
When magnetized by the magnetizing device 10 as described above,
The end portion of the permanent magnet 17 can be magnetized relatively well, and the dimension between the permanent magnet 17 and the outer peripheral surface of the rotor core 15 has a margin, so that the rotor for obtaining the dimensional accuracy can be obtained. Post-processing of the outer peripheral portion of the iron core 15 is relatively easy, and there is an advantage that the processing after assembling the rotor 14 does not require labor.

However, in the case of the rotor 14 of FIG. 8, it is necessary to process the permanent magnet 17 into a flat plate shape, but in general, in order to obtain a predetermined dimensional accuracy, in order to finish the permanent magnet 17 in a plane. It takes a lot of time and labor to process, which causes a cost increase as compared with the arc-shaped permanent magnet 7 as shown in FIG.

Further, in the case of the rotor 14 shown in FIG.
Compared with the rotor 3 of FIG. 1, the area of the permanent magnet 17 that can be arranged inside the rotor core 15 (on the cross section shown in FIG. 8) is small, and the magnetic flux generated from the permanent magnet 17 is small. Generally, the torque of a permanent magnet type motor is expressed by the following equation (1).

T = k × B × I (1) where T: motor torque k: constant determined by the number of stator windings, etc. B: air gap magnetic flux density I: current flowing in the stator winding

As can be seen from the equation (1), when the magnetic flux generated by the permanent magnet 17 decreases, the magnetic flux density of the air gap between the stator and the rotor decreases, so that the torque of the motor is reduced. Will be smaller and drive efficiency will be reduced.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a rotor constituted by incorporating a plurality of permanent magnets inside a rotor iron core, the permanent magnet and the rotating magnet. It is an object of the present invention to provide a permanent magnet motor capable of improving the manufacturability of a child and also improving performance such as driving efficiency, and a manufacturing method thereof.

[0018]

In order to achieve the above object, the invention of claim 1 has a stator having stator windings of a plurality of phases and a plurality of permanent magnets inside a rotor core. The stator is provided with a stator and a rotor rotatably arranged with a predetermined air gap inside the stator, and the rotor is rotated by sequentially energizing the stator windings. In the driven permanent magnet type motor, each permanent magnet of the rotor is formed so as to have an arc-shaped cross section, and each of the permanent magnets is arranged on the rotor core so that the convex side faces inward. Have.

According to a second aspect of the present invention, a stator having stator windings of a plurality of phases and a plurality of permanent magnets are incorporated in the rotor core, and the stator and the predetermined stator are provided in the stator. And a rotor that is rotatably disposed in a state where there is a gap, and a rotor is rotatably driven by sequentially energizing the stator windings. The magnet materials that will become permanent magnets are formed so that their cross sections are arcuate, and these magnet materials are installed in the rotor core so that the convex side faces inward. It is characterized by being magnetized by a magnetic device.

[0020]

The permanent magnet incorporated in the rotor core is formed in an arc shape, and these permanent magnets are arranged on the rotor core so that the convex side faces the inner side. Therefore, the arc-shaped permanent magnet has the convex side facing the outer side. The size between the concave-side outer surface of the permanent magnet and the outer peripheral surface of the rotor core can be made larger than in the case where the rotor magnets are arranged facing each other, and post-processing of the outer peripheral portion of the rotor core can be relatively easily performed. .

Further, since the permanent magnet is formed in an arc shape, it is easier to manufacture the permanent magnet than in the case where the permanent magnet is formed in a flat plate shape, and moreover, the area that can be arranged inside the rotor core is also large. As compared with the case where a flat permanent magnet is arranged, the size can be increased, and a large amount of magnetic flux generated by the permanent magnet can be secured.

On the other hand, each magnet material to be a permanent magnet of the rotor is formed so that its cross section has an arc shape, and these magnet materials are incorporated into the rotor core so that the convex side faces inward. By magnetizing each of these magnet materials by a magnetizing device, it is possible to satisfactorily magnetize the ends of the magnet material.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the present invention is applied to a three-phase, four-pole permanent magnet type motor will be described below with reference to FIGS. First, in FIG. 1, the stator 21 has the same structure as that of the conventional structure, and the U-phase stator windings 1U, 2U, 3U, 4U and V phase stator winding 1
V, 2V, 3V, 4V, and W phase stator winding 1W,
It is configured by inserting and arranging 2W, 3W, and 4W.

On the other hand, the rotor 23 has a rotary shaft 24.
The rotor core 25 is fitted and fixed to the rotor core 25, and four permanent magnets 27 having an arc-shaped section in this case, which are arc-shaped in this case, are inserted into the housing portion 26 formed in the rotor core 25 from the axial direction and incorporated. The stator 21 is rotatably disposed inside the stator 21 with the inner peripheral portion of the stator core 22 and a predetermined gap 28. The rotor core 25 is formed by stacking a large number of silicon steel plates having holes for forming the storage portion 26.

Each of the permanent magnets 27 is arranged so that the convex portion 27a side faces inward, and the four permanent magnets 27 are attached so that the N poles and the S poles alternate in FIG. It is magnetized.

Here, when manufacturing the rotor 23, as shown in FIG.
As shown in FIG. 5, an arc-shaped magnet material 29 (for example, ferrite) that becomes the permanent magnet 27 is inserted into the housing portion 26 of the rotor core 25, and in this state, the magnet material 29 is magnetized by the magnetizing device 30. I am trying to do it. In FIG.
Reference numeral 31 is an iron core of the magnetizing device 30, 32 is a slot formed in the iron core 31, and a coil (not shown) for passing a current for magnetizing is housed in the slot 32.

When magnetized in the state of FIG. 3, however, the magnetic flux 33a passing through the central portion of the magnet material 29, that is, the central portion of the pole, as seen in the magnetic field generated by the magnetizing device 30 of FIG. The magnetic flux 33b passing through the end portion of the magnet material 29, that is, the vicinity of the end portion of the pole, passes through the radial direction of the magnet material 29 and is distributed in a direction in which magnetization is easy. Therefore, as the magnetized permanent magnet 27, the end portion can be magnetized more favorably than in the case of the conventional permanent magnet 7 (see FIG. 7).

On the other hand, FIG. 2 shows a drive unit for a permanent magnet type motor. In FIG. 2, a switching main circuit 35 is connected to the DC power supply 34. The switching main circuit 35 is configured by connecting six transistors 36 and a free wheeling diode 37 in a three-phase bridge connection. In the switching main circuit 35, the transistor 3 included in each of the three-phase arm portions 35U, 35V, 35W
The common connection points of 6 are connected to the output lines U, V, W to the corresponding motors. These output lines U, V, W
Is the stator winding 1U, 2U, 3 of each phase of the stator 21.
U, 4U, and 1V, 2V, 3V, 4V, and 1W,
It is connected to 2W, 3W and 4W.

The control circuit 38 is a switching main circuit 35.
By controlling each of the transistors 36 of, the phases of the stator windings 1U to 4U, 1V to 4V, 1W to 4W corresponding to the adjacent two phases of the stator windings are changed by 120 degrees (electrical angle). It is configured to energize by shifting, that is, energize a known 120 degree (electrical angle). The control circuit 38 is also connected to the output lines U, V, W, and the rotation of the rotor 23 causes the stator windings 1U to 4U, 1V to 4V,
The induced voltage induced in 1 W to 4 W is detected, and the rotor 2
A motor drive signal corresponding to the rotational position of No. 3 is obtained.

In the permanent magnet type motor, however, the stator windings 1U to 4U and 1V to 4 are controlled by the control circuit 38.
When electricity is applied to V, 1W to 4W in a predetermined order, a rotating magnetic field is generated by the stator 21, and the rotor 23 is rotated by the magnetic attraction force and repulsive force that accompany it.

According to the above-mentioned embodiment, the following effects can be obtained. That is, the permanent magnets 27 incorporated in the rotor iron core 25 are formed in an arc shape, and the permanent magnets 27 are arranged in the rotor iron core 25 so that the convex portions 27a side faces inward. Compared with the one in which the convex side faces the outside (see FIG. 5),
The dimension between the outer surface of the recess 27b of the permanent magnet 27 and the outer peripheral surface of the rotor core 25 can be increased. Therefore, the rotor core 2
Since the mechanical strength of the outer peripheral part of 5 can be sufficiently secured,
Post-processing of the outer peripheral portion of the rotor iron core 25 can be performed relatively easily, and thus workability is improved, work efficiency is improved, and cost can be reduced.

Further, since the permanent magnet 27 is formed in an arc shape, when the permanent magnet is formed in a flat plate shape (see FIG. 8).
The permanent magnet 17 can be manufactured more easily than the above, and the area that can be arranged inside the rotor core 25 can be made larger than that in the case where a flat permanent magnet is arranged.
It is possible to secure a large amount of magnetic flux generated by Therefore,
It is also excellent in terms of torque and drive efficiency.

On the other hand, each magnet material 29 which becomes the permanent magnet 27 of the rotor 23 is formed so as to have an arc-shaped cross section, and each magnet material 29 is formed on the rotor core 25 with a convex portion 27.
By assembling so that the a side faces inward, and magnetizing each of the magnet materials 29 by the magnetizing device 30 in this state, it is possible to satisfactorily magnetize the ends of the magnet material 29 as described above. become. Therefore, also in this aspect, the torque and the driving efficiency can be improved.

FIG. 4 shows a second embodiment of the present invention, which is different from the first embodiment in the following points. That is, each permanent magnet 39 incorporated inside the rotor iron core 25 of the rotor 23 is formed in an arc shape which is a part of an ellipse, rather than an arc shape like the permanent magnet 27 of the first embodiment. The convex portions 39a are arranged so as to face inward.
In the case of the second embodiment, the permanent magnet 39 on the sectional view is
The area can be made larger than that of the first embodiment, and the torque and drive efficiency can be further improved.

The present invention is not limited to the embodiments described above and shown in the drawings. For example, the permanent magnets 27, 39 may be made of materials other than ferrite, and the driving method may be 120 degrees ( (Electrical angle) Not limited to energization, 1
It may be carried out by appropriately modifying it within a range not departing from the gist such as energizing at 80 degrees (electrical angle).

[0036]

According to the permanent magnet type motor of the first aspect of the present invention, each permanent magnet of the rotor is formed so as to have an arc-shaped cross section, and each of the permanent magnets has a rotor core having a convex portion on the inner side. By arranging the magnets so that they face each other, the manufacturability of the permanent magnets and the rotor can be improved, which can contribute to cost reduction, and can also improve performance such as torque and drive efficiency. It has an excellent effect.

According to the method of manufacturing a permanent magnet type motor according to the second aspect, each magnet material serving as a permanent magnet of the rotor is formed so as to have an arc-shaped cross section, and each magnet material is formed into a rotor core. Install so that the convex side faces inward,
In this state, by magnetizing each of these magnet materials with a magnetizing device, the permanent magnets can be magnetized well, and performance such as torque and drive efficiency can be improved. Produce the effect.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a motor showing a first embodiment of the present invention.

FIG. 2 is an electrical configuration diagram.

FIG. 3 is an operation explanatory view showing a magnetized state.

FIG. 4 is a sectional view of a rotor showing a second embodiment of the present invention.

5 is a diagram corresponding to FIG. 1 showing a conventional configuration.

FIG. 6 is a diagram showing a slot arrangement of a stator winding.

FIG. 7 is a view corresponding to FIG.

FIG. 8 is a sectional view of a rotor showing a different conventional configuration.

[Explanation of symbols]

1U to 4U, 1V to 4V, 1W to 4W are stator windings, 21 is a stator, 23 is a rotor, 25 is a rotor core, 27 is a permanent magnet, 27a is a convex portion, 28 is a void, 29
Is a magnet material, 30 is a magnetizing device, 39 is a permanent magnet, 39a
Is a convex part.

Claims (2)

[Claims] 1. A stator having stator windings of a plurality of phases,
The rotor core is configured by incorporating a plurality of permanent magnets inside, and the stator includes a stator and a rotor rotatably disposed in a state in which a predetermined gap is present. In a permanent magnet type motor for rotating and driving the rotor by sequentially energizing the wires, each permanent magnet of the rotor is formed to have an arc-shaped cross section, and each of the permanent magnets is projected on the rotor core. The permanent magnet type motor is characterized in that it is arranged so that its side faces inward. 2. A stator having stator windings of a plurality of phases,
The rotor core is configured by incorporating a plurality of permanent magnets inside, and the stator includes a stator and a rotor rotatably disposed in a state in which a predetermined gap is present. In a method of manufacturing a permanent magnet type motor for rotating and driving the rotor by sequentially energizing a wire, each magnet material that becomes a permanent magnet of the rotor is formed so that its cross section has an arc shape, and each of these magnets is formed. A method for manufacturing a permanent magnet type motor, characterized in that a material is incorporated into the rotor core such that a convex side faces inward, and in this state, each of the magnet materials is magnetized by a magnetizing device.