JPH05304737A - Permanent magnet type motor - Google Patents

Abstract

PURPOSE:To reduce unnecessary cogging torque by providing non-uniform width for a rotor core portion between a gap portion and an outer peripheral face of a permanent magnet for a field for respective poles. CONSTITUTION:Thickness of the portion of a rotor core 2' located between permanent magnets 6 to 9 for the field and the gap portion of the outer peripheral side is made in such a manner that the thickness will not become smaller as the relevant position of the respective permanent magnets 6 to 9 moves from the center position of each magnet to both the end sides. That is, the thickness gradually increases as the relevant position moves from the portion of rotor core 2' corresponding to the center position of the permanent magnets 6 to 9 for one pole portion to the respective directions at both end sides of the permanent magnets 6 to 9, or the thickness is the same up to the middle and then gradually increases thereafter. By doing this, the magnetic flux density component for higher harmonics in the gap portion can be made smaller so that unnecessary cogging torque can be reduced.

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 used as a motor for driving a compressor of a refrigerator or an air conditioner.

[0002]

2. Description of the Related Art In recent years, as a motor for driving a compressor of a refrigerator or an air conditioner, a permanent magnet type motor whose rotation speed is easily controlled is generally used. Hereinafter, the permanent magnet type motor generally used as described above will be described with reference to FIGS. 28 to 34.

In FIG. 28, reference numeral 141 denotes a stator having a substantially annular shape, and a semi-closed slot 141a having an opening portion 141b on the inner peripheral surface side is formed in an iron core portion of the stator 141.
For example, twelve pieces are formed so that they are arranged at substantially equal intervals in a substantially circular shape. And, in these semi-closed slots 141a, as shown in the figure, six stator coils 143u, 1
43v, 143w and 144u, 144v, 144w are wound and stored. The six stator coils 143u to 144w are configured to be supplied with a three-phase DC excitation power supply. The stator coils 143u and 144u are included in the U-phase of the three-phase DC excitation current.
However, the stator coils 143v and 144v are connected to the V phase, and the stator coils 143w and 144w are connected to the W phase, respectively.

In the figure, reference numeral 142 denotes a rotor which is arranged in the inner peripheral surface of the stator 141 with a slight gap portion 150 interposed therebetween and is constituted by laminating thin silicon steel plates. As shown, the rotating shaft 145 is fitted to the center position of the iron core portion of the rotor 142. And the rotating shaft 1
Around the 45, field permanent magnets 146, 14 made of ferrite and having an arc shape with a central angle of about 90 degrees are formed.
7, 148 and 149 are annularly arranged at orthogonal positions and at equal intervals, and each surrounds the rotating shaft 145 at the center position. Then, between the permanent magnets for field 146 to 149 and the iron core portion of the rotor 142, there is a minimum gap (not shown) of about 0.1 mm to 0.5 mm for assembling the rotor 142. It was created so that it cannot be done.

Of the field permanent magnets 146 to 149 provided on the rotor 142, the field permanent magnets 146 and 148 facing each other are magnetized to the N pole and the other field magnets facing each other. On the contrary, the permanent magnets 147 and 149 are magnetized to the S poles so that the N poles and the S poles are alternately arranged.

In the permanent magnet type motor having the above-described structure, a motor driving device (not shown) outputs a U-phase, a V-phase, and a W-phase corresponding to the stator coils 143u to 144W of the stator 141, respectively. The rotor 142 is configured to be rotationally driven by a magnetic attraction force and a repulsive force generated by energizing each of the two phases in a predetermined order at an electrical angle of 120 degrees.

By the way, in the permanent magnet type motor having such a structure, the magnetic flux distribution of the air gap portion 150 existing between the stator 141 and the rotor 142 may have various distributions depending on the design such as air gap size. Normally, it has a substantially trapezoidal wave shape with respect to the electrical angle as shown in FIG. And, in such a void magnetic flux density distribution,
Many harmonic magnetic flux density components such as the next and seventh harmonics are included, and a large number of energy components are present in the air gap by these harmonic magnetic flux density components.

On the other hand, the stator coils 143u to 144w
Is 30 degrees to 15 degrees per pole for the DC excitation current in terms of electrical angle.
As shown in FIG. 32, the magnetic flux of a portion corresponding to one electrical pole of 30 ° to 150 ° is applied to generate a driving torque by energizing for 120 ° of 0 °. ing.

Here, the drive torque generated for one phase of the motor can be expressed by the following equation (2) from the current determined by the voltage / current equation of the following equation (1). V = R × i + L × d (i) / dt + k × N × B (1) V: voltage R: resistance of stator coil i: current L: inductance of stator coil k: number of turns of stator coil Constant N: Number of rotations of rotor B: Magnetic flux density of air gap acting on stator coil in energization section T = G × B × I (2) T: Driving torque of motor G: Number of turns of stator coil Constant I: winding current

From these relational expressions (1) and (2), when the rotation speed of the rotor 142 increases, the stator coil 143 is increased.
The DC exciting current flowing through u to 144w is reduced, and the drive torque of the motor is also reduced accordingly.
Therefore, conventionally, as shown in FIG. 33, the time is accelerated by passing electricity so that the magnetic flux of a portion corresponding to 15 to 135 degrees in electrical angle for one pole acts on the stator coils 143u to 144w. By reducing the magnetic flux density of the air gap acting on the stator coils 143u to 144w, the current flowing does not decrease even when the rotation speed increases, and the required driving torque is obtained. They were facing each other by adopting the method of driving.

[0011]

The conventional permanent magnet type motor having the above-mentioned structure has the following problems.

First, among the energy components generated by the above-mentioned air gap harmonic magnetic flux density components, especially the air energy components such as the 12th, 24th, and 36th order are in the iron core portion of the stator 141. Due to the presence of the opening portions 141b of the twelve semi-closed slots 141a, the interaction with the higher harmonic components of the air gap magnetic flux density causes FIG.
As shown in the actual measurement example, so-called cogging torque is generated. Furthermore, the stator 141 and the rotor 14
The magnetic flux density distribution in the air gap portion 150 existing between the two is because the magnetic flux in the vicinity of the magnetic pole boundary passes through the iron core portion of the rotor 142 and is short-circuited to the opposite poles of the field permanent magnets 146 to 149. The distribution changes from a rectangular wave shape to a shape slightly closer to a sine wave shape, and cogging torque is generated. Although this cogging torque is superposed on the drive torque of the motor, it does not act as an effective drive torque and is an unnecessary torque that gives vibration to the rotor 142. Therefore, there is a problem that this cogging torque is transmitted to the frame of the motor or a device driven by the motor, and causes vibration or noise generated due to the vibration.

Further, a portion having an electric angle of 120 degrees for energization is 30 to 150 degrees as an electric angle shown in FIG.
Even if the shaded portion corresponding to the angle is changed to the shaded portion corresponding to the electrical angle of 15 to 135 degrees shown in FIG. 33, the change in the air gap magnetic flux density acting on the stator coils 143u to 144w is changed. Is not large, and as shown in FIG. 34, only a slight improvement is obtained as compared with the normal rotation speed.

[0014]

The present invention has been made in order to solve the above-mentioned technical problems, and is a stator in which a plurality of stator coils are wound around a substantially annular stator core. An arc-shaped permanent magnet for field magnets is continuously and alternately formed as a north pole and a south pole on a rotor and a rotor core that is concentric with the inner peripheral surface of the stator and has a slight gap. In the permanent magnet type motor, which has a rotor arranged in a substantially circumferential shape as described above and drives the rotor to rotate by sequentially energizing the stator coil, The present invention provides a permanent magnet type motor characterized in that the width of the rotor core portion existing between the outer peripheral surface and the gap portion is not uniform.

Further, the width of the rotor core portion is formed so as not to be narrowed at least in the respective directions from the pole center position of the field permanent magnet for one pole toward both ends. A permanent magnet characterized in that it is formed so as not to be narrowed at least from one end side of the pole permanent magnet for field magnet toward the other end side, and the widest part is directed in the same direction. A magnet type motor is provided.

Further, a stator in which a plurality of phases of stator coils are wound around a substantially annular stator iron core, and a rotor arranged concentrically with the inner peripheral surface of the stator and having a slight gap therebetween. An arc-shaped permanent magnet for field magnets is continuously and alternately arranged on the iron core to form N poles and S poles.
A permanent magnet type motor having a rotor arranged in a substantially annular shape so as to form a pole, and rotatingly driving the rotor by sequentially energizing the stator coil. A gap is formed in the rotor core portion on the inner side or outer side or both sides thereof in the radial direction so as not to be narrowed at least in the respective directions from the vicinity of the pole center position of the field magnet. , Especially this gap is the inner peripheral surface of the permanent magnet for the field,
By an arc surface formed by an arc having a curvature smaller than that of the arc forming the inner peripheral surface, or by an outer peripheral eye of the field permanent magnet and an arc having a curvature larger than the curvature of the arc forming the outer peripheral surface. The present invention provides a permanent magnet type motor characterized by being formed by a formed arc surface.

Further, a stator in which a plurality of phases of stator coils are wound around a substantially annular stator iron core, and a rotor arranged concentrically with the inner peripheral surface of the stator and having a slight gap therebetween. An arc-shaped permanent magnet for field magnets is continuously and alternately arranged on the iron core to form N poles and S poles.
With a rotor positioned in a substantially annular shape so as to become a pole,
In a permanent magnet type motor that drives the rotor to rotate by sequentially energizing the stator coils, the width of the rotor core portion existing between the outer peripheral surface of the field permanent magnet for one pole and the gap portion. Is formed so that it does not become narrower at all as it goes from the pole ends to the pole center position,
In addition, the residual magnetic flux density of the permanent magnet for the field is Br (tesl
a), the thickness dimension on the pole both ends of the rotor core that separates the air gap portion existing between the stator and the rotor and the field permanent magnet is t (mm), and the field permanent magnet. When the thickness dimension of the magnet in the light direction is 1 (mm), the thickness dimension t of the rotor core is within the range of Br × 0.05 × l ≦ t ≦ Br × 0.35 × l. The present invention provides a characteristic permanent magnet type motor.

[0018]

In the permanent magnet type motor of the present invention, the rotor core existing between the arc-shaped permanent magnet for field magnet and the air gap part is
It is formed to have the same width up to the middle as it goes from the center position of the pole permanent magnet for the field magnet to both ends, or to gradually widen from the center position, or to form an arc shape. A gap is formed on the inner circumference side or the outer circumference side of the field permanent magnet so as not to be narrowed at least in the respective directions from the vicinity of the pole center position of the field permanent magnet to both ends. As a result, it is possible to obtain the harmonic magnetic flux density component of the void magnetic flux distribution in the void portion reduced, so that it is possible to reduce unnecessary cogging torque as much as possible.

Further, from the void portion on one end side of the arc-shaped permanent magnet for field magnet toward the void portion on the other end side,
The air gap magnetic flux density in the air gap is constant halfway and then gradually decreases, or gradually decreases from one end side to the other end side. It is possible to greatly change the amount of the air gap magnetic flux density applied by the child coil.

Further, the width of the rotor core existing between the arc-shaped permanent magnet for field magnet and the void portion is formed so as not to be narrowed at least from the pole both ends toward the pole center position. Since the air gap magnetic flux distribution for 120 degrees (electrical angle) in the air gap portion for one pole can be made substantially constant, it becomes possible to reduce the torque ripple as much as possible.

[0021]

EXAMPLE As a first example of the present invention, a three-phase 4
A case where the present invention is applied to a pole permanent magnet type motor will be described with reference to FIGS.

First, reference numeral 1 in FIG. 1 denotes an annular, disk-shaped stator, and this stator 1 is composed of a stator core 1'and stator coils 3u, 3v, 3w and 4u, 4v, 4w. ing. The stator core 1'has a substantially annular shape, and the stator core 1'has semi-closed slots 1a having openings 1b on the inner peripheral surface side and formed, for example, in a circumferential shape so as to have 12 equal intervals. Has been done. Then, in the semi-closed slot 1a, as shown in the figure, six sets of stator coils 3u to 4 are provided.
The w is wound around a predetermined semi-closed slot 1a and accommodated therein. The stator core 1'and the stator coils 3u to 4w constitute the stator 1. The stator coils 3u to 4w are configured to be supplied with a three-phase direct-current exciting current from a direct-current power supply 11 described later. Among the three-phase direct-current exciting currents, the stator coil 3u is added to the U-phase. And 4u, the stator coil 3v for V phase
And 4v are connected so that the stator coils 3w to 4w respectively correspond to the W phase.

The rotor 2 is arranged on the inner peripheral portion of the concentric circle of the stator 1 so that a slight gap portion 10 is evenly present between the inner peripheral surface of the stator 1. This rotor 2
Rotor core 2 ', rotary shaft 5 and field permanent magnets 6, 7,
It is composed of 8 and 9. The rotor core 2'is
For example, it is formed by laminating a large number of thin plate-shaped silicon steel plates, and as described above, it is arranged such that some void portions 10 are uniformly present between the inner peripheral surface of the stator 1. Further, as shown in FIG. 2, the rotor core 2'has the rotating shaft 5 fitted in the central position. At a position slightly inward of the outer peripheral surface of the rotor iron core 2 ', a circular arc shape having a central angle of about 90 degrees is formed.
For example, four field permanent magnets 6 to 9 made of ferrite
However, they are fixedly arranged in a substantially circumferential shape so that there are equal intervals. Of the field permanent magnets 6 to 9, the field permanent magnets 6 and 8 facing each other are magnetized to, for example, N poles, and the other field permanent magnets 7 and 9 facing each other are opposite. Is magnetized to the S pole, and the N pole and the S pole are alternately arranged. These field permanent magnets 6 to 9
And the thickness of the rotor core 2'existing between the rotor core 2'and the space 10 located on the outer peripheral side of the rotor core 2 '
The thickness of the rotor core 2 does not decrease at all from the respective center positions of the rotor core 2 toward both ends (in other words, the rotor core 2 corresponding to the center position of the one-pole field permanent magnet). It is configured such that the thickness gradually increases from the ‘part” toward both ends of the field permanent magnet, or the thickness is the same halfway and then gradually increases). There is.

Next, the electrical structure of an inverter power source, which is widely used for driving the permanent magnet type motor in this embodiment, will be described with reference to FIG. 1
Reference numeral 1 denotes a DC power supply, and a switching main circuit 12 is connected to the DC power supply 11. This switching main circuit 12 has six pairs of transistors 13 and free wheeling diodes 14, and these six pairs of transistors 13 and free wheeling diodes 14 are three-phase bridge-connected and have three-phase arm portions 12u. , 12v and 12w respectively have common connection points of the transistors 13 connected to output lines corresponding to the U-phase, V-phase and W-phase, respectively. The output lines corresponding to the U-phase, V-phase, and W-phase are connected to the respective terminals of the stator coils 3u and 4u, the stator coils 3v and 4v, and the stator coils 3w and 4w that are Y-connected. Reference numeral 15 is a control circuit for giving a control signal to the transistor 13 arranged in the switching main circuit 12, and the stator coils 3u and 4u, the stator coils 3v and 4v, and the stator coils 3w and 4w adjacent to each other for two phases. The stator coil is energized with the electrical angle shifted by 120 degrees. The control circuit 15 is also connected to the output lines corresponding to the U phase, the V phase, and the W phase, and detects the voltage induced in the stator coils 3u to 4w by the rotation of the rotor 2. , A motor drive signal corresponding to the rotational position of the rotor 2 is obtained. FIG. 4 shows a sequence of energization for each phase, and a DC exciting current of 120 degrees in electrical angle is sequentially applied to each phase.

The operation and action of this embodiment will be described below. First, the control circuit 15 supplies a control signal to the six transistors 13 provided in the switching main circuit 12. When the control signal is supplied to the transistor 13, the two adjacent stator coils 3u and 4u and the stator coils 3v and 4 of the stator coils 3u to 4w are adjacent to each other.
v is energized, and thereafter, the stator coils 3v, 4v, the stator coils 3w, 4w, the stator coils 3w, 4w, and the stator coils 3u, 4u ...
It is energized 0 degrees. In this way, the stator coils 3u to 4w
When sequentially energized for 120 degrees, a rotating magnetic field by the stator 1 is generated, and the rotor 2 starts rotational driving by a magnetic attraction force and a repulsive force.

In the permanent magnet type motor having such a structure, the rotor core 2 is located on the outer peripheral side of the field permanent magnets 6 to 9 in the rotor 2 and is sandwiched between the gap portions 10.
Since the thickness of the part ′ is formed such that the thickness gradually increases from the pole center position to both ends in the field permanent magnet for one pole, the thickness of the pole is smaller than that of the pole center position. Of the magnetic fluxes emitted from the field permanent magnets 6 to 9, the magnetic flux reaching the air gap portion 10 decreases as the distance to the both ends approaches. That is, the magnetic flux is reduced from the pole center position to both ends, and the harmonic magnetic flux density component in the air gap magnetic flux density distribution is reduced, so that it is distributed in a waveform extremely close to the shape of a sine wave as shown in FIG. Become.

Therefore, in the case of this embodiment, the harmonic magnetic flux density component of the air gap magnetic flux density is reduced as much as possible so that the air gap magnetic flux density distribution is approximated to a sinusoidal shape. As shown as an example of actual measurement, since the cogging torque can be reduced, smooth rotation drive can be performed when energized by a drive device (not shown).

Next, a second embodiment will be described with reference to FIG. FIG. 7 shows a rotor according to the second embodiment. The configuration other than the rotor 22, that is, the stator and the electrical configuration are the same as those in the first embodiment, and therefore the illustration is omitted, and the same reference numerals are used in the description. The third to fifth embodiments will be similarly described below.

Similar to the first embodiment, the rotor 22 is arranged on the inner peripheral portion of the concentric circle of the stator 1 so that some void portions 10 are evenly present. This rotor 22
Rotor core 22 ', rotary shaft 5 and field permanent magnet 26,
It is constituted by 27, 28 and 29. The rotor core 22 'is formed by laminating thin silicon steel plates, for example, and the rotating shaft 5 is fitted in the center position.
At a position slightly inside the outer peripheral surface of the rotor iron core 22 'in the radial direction, four permanent magnets 26 for field magnets, which are in the shape of an arc having a central angle of about 90 degrees, are formed.
Nos. 29 to 29 are fixedly arranged in a substantially circumferential shape so as to be evenly spaced. Of these field permanent magnets 26 to 29, the field permanent magnets 26 and 28 facing each other are magnetized to, for example, N poles, and the other field permanent magnets 27 and 29 facing each other are opposite. Is magnetized to the S pole, and the N pole and the S pole are alternately arranged.

The thickness of the rotor core 22 'existing between the field permanent magnets 26 to 29 and the air gap portion 10 is such that the pole center position of the field permanent magnet for one pole is the smallest. The thickness is gradually increased toward both ends. Further, it is located in the vicinity of the outer peripheral surface of the rotor core 22 ′ and between two adjacent field permanent magnets (for example, field permanent magnets 26 and 27) among the field permanent magnets 26 to 29. A space portion a is formed in each of the rotor cores 22 ′ that are formed so as to be orthogonal to each other.

By forming the space portion a in this way, it is possible to reduce the amount of magnetic flux reaching the air gap portion 10 from the field permanent magnets 26 to 29, and further, the space portion a.
It is also possible to adjust the amount of magnetic flux that reaches the void portion 10 by adjusting the size and the like.

The third to fifth embodiments will be described below with reference to FIGS. 8 to 10. FIG. 8 shows a rotor corresponding to the third embodiment. The rotor 32 includes a rotor core 32 ′ formed by laminating a large number of thin silicon steel plates, a rotary shaft 5 fitted in the center position of the rotor core 32 ′, and a ferrite permanent magnet 36 for a field. It is composed of 39. The field permanent magnets 36 to 39 have a semi-cylindrical shape in which the outer peripheral side has an arc shape with a central angle of about 90 degrees. The thickness of the rotor core 32 ′ existing between the arcuate outer peripheral surface and the void portion 10 is 1
The center position of the pole permanent magnet for field magnetism is formed thinnest, and the thickness gradually increases toward both ends.

FIG. 9 shows a rotor corresponding to the fourth embodiment. The rotor 42 includes a rotor core 42 ′ and a rotor core 4 which are formed by laminating a large number of thin silicon steel plates.
The rotary shaft 5 fitted in the center position of 2 ', and the permanent magnets 46 to 49 for field magnets made of ferrite. The field permanent magnets 46 to 49 have a shape of an arc having a central angle of about 90 degrees, the thickness of one pole of the field permanent magnet is the largest at the center position, and the outer peripheral surface side faces both ends. According to the above, the shape is closer to the inner peripheral surface side, that is, the thickness is gradually reduced from the center position toward both ends. By setting the shapes of the field permanent magnets 46 to 49 in this way, the field permanent magnet 46
To 49, the thickness of the rotor core 42 'existing between the outer peripheral surface of the through hole 49 and the void portion 10 is gradually increased from the pole center position of the field permanent magnet for one pole toward both ends. ing.

Further, FIG. 10 shows a rotor corresponding to the fifth embodiment. The rotor 52 includes a rotor core 52 ′ formed by laminating a large number of thin silicon steel plates, a rotary shaft 5 fitted in the center position of the rotor core 52 ′, and a ferrite field permanent magnet 56 to 56. It is composed of 59. The rotor cores in the first to fourth embodiments are
The rotor core 52 'in the present embodiment is in the form of an annular disk, but the rotor core 52' in this embodiment has a form in which two ellipses are overlapped so as to be orthogonal to each other.

The field permanent magnets 56 to 59 have an arcuate shape with a central angle of about 90 degrees, the field permanent magnet for one pole has the largest thickness at the center position, and the outer peripheral surfaces have both ends. The shape is such that it approaches the portion, that is, the thickness gradually decreases from the pole center position toward both ends. Then, the thickness of the rotor core 52 ′ existing between the outer peripheral surfaces of the field permanent magnets 56 to 59 and the gap portion 10 is increased from the center position of one pole of the field permanent magnet toward both ends. I try to gradually thicken it. The rotors of the third to fifth embodiments described above can achieve the same effects as those of the first and second embodiments.

Even if the field permanent magnet in the fifth embodiment has a shape as described in other embodiments, the same effect can be obtained. ..

Next, sixth to eleventh embodiments will be described with reference to FIGS. 11 to 20. In the following embodiments, only the rotor is shown, and the other configurations are the same as those in the above-mentioned embodiments, so the illustration thereof is omitted and the same reference numerals are used in the description.

First, a sixth embodiment will be described with reference to FIG. FIG. 11 shows a rotor corresponding to the sixth embodiment. Similar to the above-described embodiment, a rotor core 62 ′ formed by laminating a large number of thin silicon steel plates, for example, is provided on the inner peripheral portion of the concentric circle of the stator 1 with a slight gap between the inner peripheral portion of the stator 1. The portions 10 are arranged so as to be present uniformly. The rotary shaft 5 is fitted to the center of the rotor core 62 '. Four field permanent magnets 66 to 69 made of, for example, ferrite, which form an arc having a central angle of about 90 degrees, are provided at a position slightly inward of the outer peripheral surface of the rotor iron core 62 '. They are fixedly arranged in a substantially circumferential shape so that they are evenly spaced. Of these field permanent magnets 66 to 69, the field permanent magnets 66 and 68 opposed to each other are magnetized to, for example, N poles, and the other field permanent magnets 67 and 69 opposed to each other are opposite. Is magnetized to the S pole,
The north pole and the south pole are arranged alternately.

These field permanent magnets 66 to 69,
The thickness of the rotor core 62 ′ portion existing between the outer peripheral side and the void portion 10 is continuously and gradually increased from one end side to the other end side of the one-pole field permanent magnet. The rotor core 62 'is formed so as to have an increased thickness, and the thickest part of the rotor core 62' faces the same direction. Therefore, the field permanent magnets 66 to 69 are fixed at slightly distorted positions, and the thickness of the rotor core 62 ′ portion located on the outer peripheral side on one end side of the field permanent magnet for one pole and other This means that the thickness of the rotor core 62 ′ located on the outer peripheral side on the end side has the largest difference in thickness. In this way, the rotor core 62 formed by laminating silicon steel plates
', The rotor shaft 62 fitted to the center position of the rotor core 62', and the rotor 62 by the field permanent magnets 66 to 69.
Is configured.

In the permanent magnet type motor having the rotor 62 having such a structure, the magnetic flux distribution in the gap portion 10 existing between the stator 1 and the rotor 62 has a substantially triangular waveform as shown in FIG. Becomes That is, the air gap magnetic flux distribution in the air gap portion 10 corresponding to the energization section to the stator coils 3u to 4w is the air gap magnetic flux density on the one end side of the thinner one of the rotor iron core 62 'in the one-pole field permanent magnet. And the air gap magnetic flux density decreases on the thicker other end side of the rotor core 62 ′. Therefore, the maximum value of the air gap magnetic flux density is not in the vicinity of the central portion of the one-pole field permanent magnet but in the one end of the rotor iron core 62 'that is thinner.

On the other hand, the stator coils 3u to 4w are energized by 120 degrees corresponding to one pole of 30 to 150 degrees in terms of direct current excitation current, and as shown in FIG. The magnetic flux of a portion corresponding to 30 degrees to 150 degrees acts to generate the driving torque of the motor. As is conventionally done here, as shown in FIG.
As shown in, the electric field is applied to a portion corresponding to an electric angle of 15 degrees to 135 degrees with a field permanent magnet for one pole.
By performing the operation for advancing the energization start time, the air gap magnetic flux density acting on the stator coils 3u to 4w changes greatly, and the driving torque of the motor can be obtained up to a high rotational speed as shown in FIG. Like

A seventh embodiment will be described with reference to FIG. FIG. 12 shows a rotor corresponding to the seventh embodiment. The rotor 72 includes a rotor iron core 72 'formed by laminating a large number of thin silicon steel plates, a rotary shaft 5 fitted in a central position of the rotor iron core 72', and an outer periphery of the rotor iron core 72 '. Four field permanent magnets 7 made of, for example, ferrite, which are provided at a position slightly inward of the surface in the radial direction and which form a substantially arc shape with a central angle of about 90 degrees.
6, 77, 78 and 79. The field permanent magnets 76 to 79 are fixedly arranged in a substantially circumferential shape at equal intervals, and the field permanent magnets 76 and 78 facing each other are magnetized to the N pole.
The other opposing field permanent magnets 77 and 79 are oppositely magnetized to the S pole, and the N pole and the S pole are arranged alternately.

These field permanent magnets 76 to 79 are
It seems that the permanent magnet formed in an arc shape with a substantially constant thickness and a central angle of about 90 degrees is gradually shaved from the substantially central position on the outer peripheral side to the substantially central position in the radial direction of the end face on one end side. It has a shape. That is, the field permanent magnet 7
The thickness of the rotor core 72 ′ located on the outer peripheral side from the substantially central position on the outer peripheral side of 6 to 79 to the one end side is gradually increased toward the end portion. At this time, as shown in FIG.
Nos. 6 to 79 are arranged so that one end side having the smallest thickness faces the same direction.

By forming the field permanent magnets 76 to 79 so as to change the thickness in this manner, it is possible to obtain the driving torque of the motor up to a high rotational speed, as in the sixth embodiment. become.

An eighth embodiment will be described with reference to FIG. FIG. 13 shows a rotor corresponding to the eighth embodiment. The shape of the field permanent magnets 86 to 89 is substantially constant in the radial direction of the end face from one end side to the other end side on the inner peripheral side of the permanent magnet formed in an arc shape having a constant thickness and a central angle of about 90 degrees. As shown in the figure, the permanent magnet for the field is made into a shape that gradually cuts off the part reaching the center position, that is, the shape becomes thinner from the one end side to the other end side. The thinnest end faces of the magnets 86 to 89 on the other end side face the same direction. The field permanent magnets 86 to 89 are arranged at equal intervals, and the rotor core 82 ′ existing between the outer peripheral surface and the void portion 10 is arranged to have a uniform thickness.

When the shape of the field permanent magnets 86 to 89 is such a form, the magnetic flux acting on the stator coils 3u to 4w in the void portion 10 is small on one end side where the thickness is large, and the thickness is the most. Since it is increased on the thin other end side, it is possible to obtain the same effects as those of the sixth to seventh embodiments.

Next, a ninth embodiment will be described with reference to the rotor shown in FIG. A feature of this embodiment is that, unlike the sixth to eighth embodiments, as shown in the figure, a permanent magnet 96 for field magnetism is provided around the rotor core 92 '.
This is a configuration in which Nos. 99 to 99 are fixedly arranged. The shape of the field permanent magnets 96 to 99 is an arc-shaped permanent magnet having a central angle of 90 degrees and a constant thickness, and the outer peripheral surface is located at a substantially central position in the radial direction from the one end side to the other end side. The shape is such that it gradually scrapes away, that is, the shape gradually becomes thinner from the one end side toward the other end side. The field permanent magnets 96 to 99 thus formed are arranged such that the end face on the other end side having the smallest thickness is directed to the same direction on the outer peripheral surface of the rotor iron core 92 'and no gap is formed. Fixed to the rotor by gluing, etc.
2 is configured.

Even with such a rotor 92, as in the sixth to eighth embodiments, the stator coils 3u to 4 are also provided.
Since the amount of magnetic flux acting on w can be made different on the one end side and the other end side, it is possible to achieve the same effect. However, in the present embodiment, the field permanent magnets 96 to 99 are formed with a central angle of 90 degrees and fixedly arranged without a gap, but the same applies even if they are arranged at equal intervals with a slight gap. The effect of can be produced.

The tenth and eleventh embodiments will be described below with reference to FIG.
16 and FIG. 16. First, as a tenth embodiment, as shown in FIG. 15, a field permanent magnet for one pole, for example, most of the upper section having a substantially trapezoidal shape is N-shaped.
It is formed by magnetizing the poles, and by forming a small portion having a substantially triangular lower cross section as the S pole, it is possible to cause the magnetic flux to be canceled by the N pole and the S pole in these portions. In this configuration, the strength of the magnetic flux is increased.

In the eleventh embodiment, as shown in FIG. 16, the height of the field permanent magnet for one pole is changed between one end side and the other end side. The height α on one end side is made lower than the height β on the other end side so that the magnetic flux acting on the stator coils 3u to 4w is made stronger or weaker.

By fixing the field permanent magnets formed as in the tenth and eleventh embodiments to the rotor core with the weak magnetic flux side or the strong magnetic flux side facing the same direction. The same effects as those of the sixth to ninth embodiments can be obtained.

Next, twelfth and thirteenth embodiments will be described with reference to FIGS. In the following embodiments, only the rotor is shown, and the other configurations are the same as those in the above embodiments, so the illustrations are omitted and the same reference numerals are used in the description.

First, a twelfth embodiment will be described with reference to FIG. FIG. 21 shows a rotor corresponding to the twelfth embodiment. Similar to the above-described embodiment, a rotor core 102 ′ formed by laminating a large number of thin silicon steel plates, for example, is provided on the inner peripheral portion of the concentric circle of the stator 1 with a slight gap between the inner peripheral portion of the stator 1. It is arranged so that the portions 10 are evenly interposed. The rotor core 102 'has a rotary shaft 5 at the center position.
Are fitted. At a position slightly inward of the outer peripheral surface of the rotor core 102 'in the radial direction, four permanent magnets 106 to 109 made of, for example, ferrite, which form an arc having a central angle of about 90 degrees, are formed. Are formed at equal intervals and in a substantially circumferential shape, and the field permanent magnets 106 to 109 are included in the holes 103. Then, these field permanent magnets 106 to 1
09, the field permanent magnets 106 and 108 facing each other are magnetized to, for example, N poles, and the other opposing field magnets 107 and 109 are oppositely magnetized to S poles, and N. The poles and the S poles are arranged alternately.

These field permanent magnets 106 to 109
And the thickness of the rotor core 102 ′ portion existing between the outer peripheral side and the void portion 10 is different from the above-described embodiment, and any portion is formed substantially uniformly, but in this embodiment, A gap 100 is formed radially inward of the field permanent magnets 106 to 109. The gap 100 has a hole 103 for containing the field permanent magnets 106 to 109,
It is formed by the field permanent magnets 106 to 109 because the hole 103 has a characteristic shape. The shape of the hole 103 will be described.
The outer side in the radial direction of 3 is formed by an arc having the same curvature as the arc forming the outer peripheral surface of the permanent magnets for field 106 to 109, but the inner side in the radial direction of the permanent magnets for field 106 to 109. It is formed by an arc having a smaller curvature than the arc forming the inner peripheral surface. Therefore, the outer peripheral surfaces of the field permanent magnets 106 to 109 are in close contact with the hole 103, but the inner peripheral surface is in contact only in the vicinity of the pole center position, and is not in close contact with other portions. A gap 100 is formed in the gap.

As described above, the field permanent magnets 106 to 10
The magnetic flux density distribution in the void portion 10 can be approximated to a sine wave shape by configuring the inside of the radial direction 9 so as not to narrow at least the width of the gap from the pole center position toward both ends. And again
Comparing the ratio of the air gap magnetic flux density with respect to the fundamental component of the harmonic of the present example, the content of the harmonic of the present example can be reduced as shown in FIG. It is possible to reduce it as much as possible.

Further, FIG. 22 shows a rotor corresponding to the thirteenth embodiment. The rotor 112 is provided on the rotor core 112 ′, which is formed by laminating a large number of thin silicon steel plates, the rotary shaft 5 fitted to the center position of the rotor core 112 ′, and the rotor core 112 ′. It is composed of one hole 113 and ferrite permanent magnets 116 to 119 enclosed by the hole 113.

The hole 113 is different from the twelfth embodiment.
The inner side of the hole 113 in the radial direction is formed with an arc having the same polarities as the arc forming the inner peripheral surfaces of the field permanent magnets 116 to 119, but the outer side in the radial direction is It is formed by an arc having a greater ratio than the polarities of the arcs forming the outer peripheral surfaces of the field permanent magnets 116 to 119. Therefore, the inner peripheral surfaces of the field permanent magnets 116 to 119 have holes 1
Although it is in close contact with the outer peripheral surface 13, the outer peripheral surface only contacts only in the vicinity of the pole center position, and the gap 110 is formed in the other portion which is not in close contact. Field permanent magnet 11 at this time
The distance between the outer peripheral surfaces of 6 to 119 and the outer peripheral surface of the rotor iron core 112 'is formed to be substantially uniform in any part.

As described above, the field permanent magnets 116 to 1
Even if the gap 110 is formed on the outer peripheral side of 19, it is possible to obtain the same effect as that of the twelfth embodiment, and further, a gap is formed on both the inner peripheral side and the outer peripheral side of the field permanent magnet. Even if formed, the same effect can be obtained.

Further, in the twelfth and thirteenth embodiments, the gap is formed by the field permanent magnet and the hole, but the gap is formed in a portion different from the hole containing the field permanent magnet. Various modifications can be made, such as provision, within the range not departing from the gist of the present invention.

Next, fourteenth to fifteenth embodiments will be described with reference to FIGS. 24 to 27. In the following embodiments, only the rotor is shown, and the other configurations are the same as those in the above embodiments, so the illustrations are omitted and the same reference numerals are used in the description.

First, a fourteenth embodiment will be described with reference to the rotor 122 shown in FIG. Similar to the above-described embodiment, a rotor core 122 ′ formed by laminating a large number of thin silicon steel plates, for example, is provided on the inner peripheral portion of the concentric circle of the stator 1 with a slight amount of shooting between the inner peripheral portion of the stator 1. It is arranged so that the portions 10 are evenly interposed. This rotor core 122 '
The rotary shaft 5 is fitted in the central position of the. At a position slightly inward of the outer peripheral surface of the rotor core 122 'in the radial direction, four permanent magnets 126 to 129 having a central angle of about 90 degrees and having an arc shape and made of, for example, ferrite. Are arranged at equal intervals and in a substantially circumferential shape. Of these field permanent magnets 126 to 129, the field permanent magnets 126 and 128 facing each other are magnetized to, for example, N poles, and the other field permanent magnets 127 and 129 facing each other. Is magnetized to the S pole, and N
The poles and the S poles are arranged alternately.

These field permanent magnets 126 to 129
And the thickness of the rotor core 122 'existing between the air gap portion 10 located on the outer peripheral side of the rotor core 122',
6 to 129, the thickness is not reduced at least from the pole ends toward the pole center position (conversely speaking, the rotor core 1 corresponding to the pole center position).
The 22 'portion is thickest and is gradually thinned so that at least the thickness does not spread toward the pole ends).

These field permanent magnets 126 to 129
Has a residual magnetic flux density of Br (Tesla), a radial thickness dimension of 1 (mm), and a rotor iron core 122 'on both pole sides having a thickness dimension of t.
(mm). At this time, the rotor core 122 '
The thickness t (mm) of the portion corresponding to the extreme end sides of is in a relation as shown by Br × 0.05 × l ≦ t ≦ Br × 0.35 × l.

Further, FIG. 25 shows a rotor 132 corresponding to the fifteenth embodiment. This rotor 132
Is a rotor core 132 'formed by laminating a large number of thin silicon steel plates, a rotary shaft 5 fitted to the center position of the rotor core 132', and a ferrite field provided on the rotor core 132 '. It is composed of permanent magnets 136 to 139 for magnetism.

The point different from the fourteenth embodiment is the shape of the field permanent magnets 136 to 139, and the field permanent magnets 136 to 139 of this embodiment have a shape on the outer peripheral side which is the same as that of the fourteenth embodiment. This is the same as the field permanent magnets 126 to 129 in the example, but the inner peripheral side is formed in a straight line shape, and has an overall shape like a kamaboko. At this time, the thickness dimension l (mm) of the permanent magnets 136 to 139 for field use is the value obtained by averaging the whole.

The distributions of the air gap magnetic flux densities and the combined torques in the fourteenth and fifteenth embodiments are shown in FIGS. 26 and 27. The rotor core 122 having the shapes as in these embodiments is shown.
And 132, the field permanent magnets 126 to 129.
In addition, among the magnetic fluxes emitted from the field permanent magnets 136 to 139, the magnetic flux tends to flow toward the pole both ends by passing through the rotor cores 122 ′ and 132 ′ from the pole ends toward the pole center position. Since magnetic poles are sized so that magnetic saturation easily occurs on both pole sides as compared with the pole center position, the magnetic flux flows from the air gap portion 10 to the stator core 1 '. That is, in the conventional example, the magnetic flux increases at the pole center position in the air gap portion 10, but this magnetic flux flows toward both pole ends and, moreover, gradually flows from the air gap portion 10 to the stator 1, so that the air gap magnetic flux density is averaged. As shown in FIG. 26, the upper end portion of the sine wave shape is substantially flat in a 120 degree (electrical angle) section of at least one pole. Therefore, when a substantially constant current flows through the stator coils 3u to 4w in this 120-degree (electrical angle) section, the combined torque generated by the interaction has a waveform with very few irregularities as shown in FIG. It is possible to obtain various rotary drive.

Although the first to fifteenth embodiments described above are applied to a three-phase four-pole permanent magnet type motor, the present invention is not limited to this type of motor, and various modifications are possible. It is possible to carry out.

Further, in the above-mentioned embodiment, the rotor core constituted by laminating a plurality of thin silicon steel plates is applied, but the present invention is not limited to this, and it is made of a magnetic material. Any rotor core can be applied and implemented, and the same effects as those of the above-described embodiment can be achieved.

Further, in the above-mentioned embodiment, the permanent iron core type motor to which the permanent magnet made of ferrite is applied is explained, but the present invention is not limited to this, and the permanent magnet such as alnico or rare earth is used. It is also possible, and it is possible to obtain the same effect as the above-mentioned embodiment. Furthermore,
The method of driving the motor is not limited to the method described above,
It is also possible to adopt various driving methods.

[0070]

According to the permanent magnet type motor of the present invention, the width of the rotor core portion existing between the outer peripheral surface of the field permanent magnet and the air gap portion is set to one pole of the field permanent magnet. The width is gradually increased from one end side to the other end side, or is formed to have the same width in the middle and then gradually widened, or one pole is formed on the inner or outer circumference side of the arc-shaped permanent magnet for field. Since it is configured to form a gap so that it does not narrow at least from the vicinity of the pole center position of the field permanent magnet toward each direction on both ends, Since the harmonic magnetic flux density component can be reduced as much as possible, the cogging torque is reduced, and the vibration generated by the permanent magnet type motor and the equipment driven by this motor, and the noise generated by this vibration are also reduced. Etc. can be reduced, in which excellent effects such as.

Further, the air gap magnetic flux density of the one-pole field permanent magnet on which the stator coil acts can be changed greatly depending on the conduction angle from one end side to the other end side. Therefore, it has an excellent effect that the driving torque of the motor can be obtained up to the range of high rotation speed.

[Brief description of drawings]

FIG. 1 is a plan view of a permanent magnet type motor according to a first embodiment.

FIG. 2 is an enlarged view of the rotor in FIG.

FIG. 3 is an electrical configuration diagram of a permanent magnet type motor.

FIG. 4 is a diagram showing an energization sequence to a stator coil.

FIG. 5 is a diagram showing a distribution of void magnetic flux density in the present invention.

FIG. 6 is a diagram showing actually measured values of cogging torque in the first embodiment.

FIG. 7 is an enlarged view of a rotor according to a second embodiment.

FIG. 8 is an enlarged view of a rotor according to a third embodiment.

FIG. 9 is an enlarged view of a rotor according to a fourth embodiment.

FIG. 10 is an enlarged view of a rotor according to a fifth embodiment.

FIG. 11 is an enlarged view of a rotor according to a sixth embodiment.

FIG. 12 is an enlarged view of a rotor according to a seventh embodiment.

FIG. 13 is an enlarged view of a rotor according to an eighth embodiment.

FIG. 14 is an enlarged view of a rotor according to a ninth embodiment.

FIG. 15 is a diagram showing the shape of a permanent magnet for a field magnet according to a tenth embodiment.

FIG. 16 is a diagram showing the shape of a permanent magnet for field magnets according to an eleventh embodiment.

FIG. 17 is a diagram showing the distribution of air gap magnetic flux densities in the sixth to eleventh embodiments.

FIG. 18 is a diagram showing a relationship between an energization section and a magnetic flux density distribution in an air gap

FIG. 19 is a diagram showing the relationship between the energization section and the air gap magnetic flux density distribution.

FIG. 20 is a diagram showing motor characteristics.

FIG. 21 is an enlarged view of the rotor according to the twelfth embodiment.

FIG. 22 is an enlarged view of a rotor according to a thirteenth embodiment.

FIG. 23 is a comparative diagram of the harmonic components of the conventional example and the present invention.

FIG. 24 is an enlarged view of a rotor according to a fourteenth embodiment.

FIG. 25 is an enlarged view of the rotor according to the fifteenth embodiment.

FIG. 26 is a diagram showing the distribution of air gap magnetic flux density in the fourteenth and fifteenth examples.

FIG. 27 is a diagram showing combined torque in the fourteenth and fifteenth embodiments.

FIG. 28 is a plan view of a conventional permanent magnet type motor.

29 is an enlarged view of the rotor in FIG. 28.

FIG. 30 is a diagram showing a conventional air gap magnetic flux density distribution.

FIG. 31 is a diagram showing actual measured values of conventional cogging torque.

FIG. 32 is a diagram showing a relationship between an energization section and a magnetic flux density distribution in an air gap.

FIG. 33 is a diagram showing the relationship between the energization section and the air gap magnetic flux density distribution.

FIG. 34 is a diagram showing a conventional motor characteristic.

[Explanation of symbols]

 1 Stator 1 ′ Stator core 2 Rotor 2 ′ Rotor core 3u, 3v, 3w Stator coil 4u, 4v, 4w Stator coil 6, 7, 8, 9 Permanent magnet for field 10 Air gap

Claims (7)

[Claims] 1. A stator in which a plurality of phases of stator coils are wound around a substantially annular stator iron core, and a rotor which is concentric with the inner peripheral surface of the stator and has a slight gap therebetween. An iron core is provided with a rotor in which arc-shaped permanent magnets for field magnets are continuously and alternately arranged so as to have N poles and S poles in a substantially circumferential shape, and the rotor coil is rotated by sequentially energizing the stator coil. In a permanent magnet motor for rotating a child, the width of the rotor core portion existing between the outer peripheral surface of the field permanent magnet and the gap portion in one pole is not uniform. Shaped motor. 2. The width of the rotor core portion is formed so as not to be narrowed at least in the respective directions from the pole center position of the field permanent magnet for one pole toward both ends. The permanent magnet type motor according to claim 1. 3. The width of the rotor core portion is formed so as not to become narrower at least from one end side to the other end side of the field permanent magnet for one pole, and the widest portion. 2. The permanent magnet type motor according to claim 1, wherein the magnets are oriented in the same direction. 4. A stator in which a plurality of phases of stator coils are wound around a substantially annular stator iron core, and a rotor which is concentric with the inner peripheral surface of the stator and has a slight gap therebetween. And a rotor in which arc-shaped permanent magnets for field magnets are continuously arranged in a substantially annular shape so as to have N poles and S poles alternately, and the rotor coil is energized sequentially by the rotor. In the permanent magnet type motor for driving the rotor to rotate, the rotor core portion on one side or inside or outside of the field permanent magnet in one pole is located at both ends from near the pole center position of the field permanent magnet. A permanent magnet type motor characterized in that a gap is formed so as not to be narrowed at least in the respective directions of the side. 5. The gap is an arc surface formed by an inner peripheral surface of the field permanent magnet and an arc having a curvature smaller than a curvature of an arc forming the inner peripheral surface, or the field permanent magnet. The permanent magnet motor according to claim 4, wherein the permanent magnet motor is formed by an outer peripheral surface of the magnet and an arc surface formed by an arc having a curvature larger than a curvature of an arc forming the outer surface. 6. A stator in which a plurality of phases of stator coils are wound around a substantially annular stator iron core, and a rotor which is concentric with the inner peripheral surface of the stator and has a slight gap therebetween. And a rotor in which arc-shaped permanent magnets for field magnets are continuously arranged in a substantially annular shape so as to have N poles and S poles alternately, and the rotor coil is energized sequentially by the rotor. In the permanent magnet type motor for rotating the rotor, the width of the rotor core portion existing between the outer peripheral surface of the field permanent magnet for one pole and the air gap portion is increased from the pole end side toward the pole center position. A permanent magnet type motor characterized by being formed so as not to be narrowed at least. 7. The residual magnetic flux density of the permanent magnet for field magnet is set to Br.
(Tesla), the thickness dimension on the pole end sides of the rotor core that separates the air gap portion existing between the stator and the rotor and the permanent magnet for the field is t (mm), When the radial thickness of the permanent magnet is 1 (mm), the thickness t of the rotor core should be within the range of Br × 0.05 × l ≦ t ≦ Br × 0.35 × l. The permanent magnet type motor according to claim 6, which is characterized in that.