KR19980079929A - Permanent magnet rotary electric machine - Google Patents

Abstract

In a permanent magnet rotary electric machine comprising a stator and a rotor in which a plurality of permanent magnets are embedded in the rotor core, the stator slot pitch angle s, the slit width angle S of the stator, and the pole piece of the rotor. Since the angle θ has a relationship of θ = n × τs + A × S (n is an integer and A is a constant of 0 ≦ A ≦ 1 depending on the flow of magnetic flux in the slot portion), the waveform of the induced voltage is closer to the sine wave. can do. As the permanent magnet having a plurality of magnetic centers is used, the magnetic flux acting in the gap increases, and the efficiency is improved because it is concentrated in the energizing section.

Description

Permanent magnet rotary electric machine

BACKGROUND ART Permanent magnet rotary electric machines are widely used as brushless DC motors of 1 kW or less because magnetic fluxes of field magnetic poles can be obtained from permanent magnets and control of high efficiency is relatively easy compared to induction motors.

BACKGROUND ART In a permanent magnet rotary electric machine, as described in Japanese Patent Laid-Open No. Hei 6-339240, a motor having high torque and high efficiency has been developed. This has the following configuration.

The stator has a plurality of slots, in which three-phase stator windings are wound. The rotor is fixed by fitting the rotor core to the rotating shaft. In the rotor core, a plurality of permanent magnets having an arcuate cross section perpendicular to the rotating shaft are assembled. The stator surrounds the rotor and there is a predetermined gap between the stator core and the rotor core.

Each permanent magnet is arranged so that the convex portion faces the rotation axis side (center side). The permanent magnet is magnetized so that the N pole and the S pole are alternated. The magnetization of this permanent magnet causes magnetic anisotropy (magnetic orientation), and the magnetism is concentrated at one point. That is, the self-center is one. The electric motor controls the rotation speed with an inverter of 120 degree energization in order to perform a shiftable operation.

Further, in the permanent magnet type rotor, the rotor iron core is made by stacking a plurality of steel sheets punched out by punching holes for inserting permanent magnets. The steel sheets are laminated so that the punching holes coincide. In the permanent magnet rotor, it is necessary to reliably fix the permanent magnet inside the iron core.

Japanese Patent Application Laid-Open No. 7-322538 has a bow-shaped permanent magnet in which a recessed permanent magnet is disposed toward a rotation axis side, and a suppressor is provided between the permanent magnet and the rotation shaft to fix the permanent magnet to the rotor iron core. A permanent magnet rotor is described.

Japanese Patent Laid-Open No. 9-9537 describes a permanent magnet type rotor in which a magnet is arranged in a V shape inside a rotor iron core.

The present invention relates to a permanent magnet rotary electric machine having a rotor having a plurality of permanent magnets embedded in a rotor iron core.

In the conventional permanent magnet rotary electric machine as described above, various gap magnetic flux distributions can be obtained by the arrangement of magnetism of the permanent magnet. The torque of the motor is generated only while current is flowing in the stator winding, and can be expressed by the following equation.

T: torque of motor, m: constant of motor, K: constant related to winding of stator winding, B: magnetic flux density of gap, Lq: q-axis inductance, Ld: d-axis inductance,

Iq: q-axis winding current, Id: d-axis winding current

In order to increase the torque in Equation 1, it is necessary to increase the magnetic flux density of the gap and to concentrate the magnetic flux of the magnet.

Further, in the manner of energizing 120 degrees (electric angle), since the 120 degrees (electric angle) of the magnetic flux generated by the permanent magnet as one pole acts as a torque, the oblique portion of FIG. 3 of Japanese Patent Application Laid-Open No. 6-339240 The magnetic flux in the non-conduction section, i.e., 0 degrees to 30 degrees and 150 degrees to 180 degrees (electric color) in the region becomes useless.

Moreover, in the permanent magnet rotary electric machine of Unexamined-Japanese-Patent No. 7-322538 as described above, all the suppression force for fixing a permanent magnet to a rotor iron core is the same direction as a centrifugal force. Therefore, since the portion of the rotor iron core supporting the centrifugal force is only the bridge portion between the permanent magnets, when the number of revolutions is thousands of times, it is necessary to thicken the bridge portion, and the permanent magnets become smaller so that they can be obtained from the permanent magnets. The disadvantage is that the amount of magnetic flux present is reduced.

In the permanent magnet rotary electric machine of the conventional structure, since magnetic flux change exists compared with the surface magnet type in which magnetic flux changes continuously, since magnetic flux changes are severe, a harmonic component exists in an organic voltage waveform, and a waveform exists. It becomes a distortion waveform compared with this sine wave.

Since the distortion waveform makes it difficult to control the sensorlessly, there are many control restrictions.

An object of the present invention is to increase the magnetic flux by the permanent magnet acting in the gap to the maximum, and to reduce the magnetic flux of the portion corresponding to the non-conduction section by the maximum, to increase the drive torque of the motor, to improve the miniaturization or drive efficiency It is to provide a permanent magnet rotary electric machine that makes it possible.

Another object of the present invention is a punching hole for fixing the rotor laminated iron core to the gap side than the magnet, and the pressing force for fixing by the rivets, etc., both in the opposite direction to the centrifugal force and at the same time supports the centrifugal force. By providing a structure which is also supported by rivets and end plates, it is possible to provide a permanent magnet rotary electric machine having a firm permanent magnet fixing means.

Another object of the present invention is to provide a permanent magnet rotary electric machine capable of bringing the waveform of an induced voltage close to a sine wave, facilitating sensorless control, increasing drive torque of the motor, and miniaturizing or improving drive efficiency. It is to offer.

A feature of the present invention for achieving the above object is that a permanent magnet embedded in a rotor iron core has a plurality of bow shapes in a cross section perpendicular to the rotation axis, has a plurality of magnetic centers, and the bow-shaped recess is a stator. It is arrange | positioned so that it may face in a direction.

According to the present invention, in the portion corresponding to the energizing section, the area of the permanent magnet can be increased, and the magnetic flux density by the permanent magnet acting in the gap between the stator and the rotor can be increased, thereby improving the motor efficiency. Can be.

Another feature of the present invention is that when the slot pitch angle (machine angle) of the stator is τs and the slit width angle (machine angle) of the stator is S, the pole piece angle (machine angle) θ of the rotor is almost,

θ = n × τs + A × S

(n is an integer and A is a constant of 0≤A≤1 depending on the flow of the slot magnetic flux).

According to the above feature, the induced voltage waveform is close to the sine wave, facilitates sensorless control, and improves the motor efficiency.

The slot is a groove provided in the stator for winding the stator winding, and the slot pitch angle is a center angle that the slot pitch makes about the rotation axis. A slit is an opening of a slot, and a slit width angle is the center angle which the slit created about the rotation axis. A pole piece is an iron core part between the permanent magnet and the outer periphery of a rotor among the iron cores of a rotor, and a pole piece angle is the center angle which the boundary of a pole piece and a permanent magnet makes centering on a rotation axis.

In addition, the permanent magnet rotary electric machine of the present invention may be used as a permanent magnet rotary electric machine of an outer rotation in which a rotor is disposed around the stator, and the same effect as the above-described effect can be obtained.

1 is a partial sectional view of a permanent magnet rotary electric machine of the first embodiment;

Fig. 2 is a sectional view of the permanent magnet rotary electric machine of the first embodiment.

3 is a diagram showing the pressing force F and the centrifugal force G in the rotor iron core 7;

4 shows a rivet 12 connecting the rotor iron core 7.

Fig. 5 shows the magnetic flux density distribution of the rotor iron core 7;

6 is a view comparing the efficiencies of the first embodiment, the second embodiment, and the conventional example.

FIG. 7 shows eight rivets 12 connecting the rotor iron cores 7.

8 is a diagram showing an induced voltage waveform when the pole piece side angle θ is changed.

Fig. 9 is a graph showing the relationship between the pole piece side angle θ and the waveform variation rate of a permanent magnet;

10 is a diagram showing an induced voltage waveform when ψ is changed.

11 shows the relationship between ψ and waveform variation rate.

12 is a diagram showing an induced voltage waveform when the slit width angle S is changed.

Fig. 13 shows the relationship between the slit width angle S and the waveform variation rate;

14 is a diagram showing an induced voltage waveform when the slot pitch [tau] s is changed.

Fig. 15 is a diagram comparing magnetic flux densities of gap portions in the first embodiment and the prior art example.

16 shows a permanent magnet rotary electric machine of a second embodiment;

17 shows a permanent magnet rotary electric machine having a magnetic center of 2 out of 3 points;

18 shows a permanent magnet rotary electric machine having a magnetic center of 2 out of 5 points;

Fig. 19 shows the relationship between the gap magnetic flux density / magnetic magnetic flux density and efficiency;

20 shows the relationship between the number of magnetic centers and the efficiency.

21 is a longitudinal sectional view of a scroll compressor using an electric motor of the present invention.

Explanation of symbols for the main parts of the drawings

a, b, c, d, e: magnetic flux concentration points

1: stator

2: stator iron core

3: stator slot

4: stator opening

5: gap

6: rotor

7: rotor iron core

8a: permanent magnet

9: axis of rotation

θ: pole piece angle of permanent magnet

ψ: polar color of the permanent magnet

S: Slit width angle of stator

τs: slot pitch angle

(First embodiment)

A three-phase, four-pole permanent magnet rotary electric machine according to a first embodiment of the present invention will be described. 2 is a cross-sectional view perpendicular to the rotation axis of the permanent magnet rotary electric machine. FIG. 1 is an enlarged view of a portion of one pole of four poles of the permanent magnet rotary electric machine of FIG. 2. In FIG. 2, the stator 1 includes a stator iron core 2 having 24 slots 3 and stator windings U +, U- and V phases of the U phase inserted into the slot 3. It consists of stator windings W +, W- on V +, V- and W. Each slot 3 has an opening 4. The opening 4 is also called a slit.

The rotor 6 includes a rotor shaft 9, a rotor iron core 7 fitted and fixed to the rotor shaft 9, and a permanent magnet 8 made of ferrite inserted into the rotor iron core 7 and assembled. It is mainly composed of four. The stator 1 surrounds the rotor 6 and there is a predetermined gap 5 between the stator 1 and the rotor 6.

The portion of the iron core 7 between the permanent magnet 8 and the outer circumference of the rotor 6 is called a pole piece.

The shape of the cross section of the permanent magnet 8 perpendicular to the rotation axis 9 is bow-shaped, and the center of the bow is two points a and b as shown in FIG. The permanent magnet 8 is arranged on the rotor iron core 7 so that the concave portion faces the stator direction. The four permanent magnets 8 are magnetized so that the N poles and the S poles alternate with each other so that the polarities of the adjacent permanent magnets 8 are reversed.

The permanent magnet 8 is magnetized so that the magnetic flux concentrates at two positions a and b as shown in FIG.

The permanent magnet 8 shown in FIG. 5 has two bow-shaped cross sections with a center of curvature. The distance between adjacent permanent magnets 8, i.e., the width of the auxiliary magnetic pole, is minimized at the middle portion in the radial direction, and the distance is increased from the middle portion toward the outer circumferential side.

For example, in a motor with an output of 1 kw and a radius of 112 mm, the distance between two magnetic center points (shown as d1 in FIG. 5) is 1 mm, the minimum distance from adjacent permanent magnets is 1 mm x 2, from the middle radius. As it falls, the distance increases, and the maximum value (d4 × 2 in FIG. 5) is about 3 mm × 2. Moreover, it is a distance of 0.5 mm with the surface of the rotating shaft 9.

The rotor iron core 7 of FIG. 1 is produced by laminating a large number of silicon steel sheets. In the silicon steel sheet, a hole 7b for inserting the permanent magnet 8 and a hole 7b for pushing the rivet connecting the silicon steel sheet are formed. The hole 7b is provided on the outer circumferential side of the permanent magnet 8a.

As shown in Fig. 3, when the rivet is pushed into the hole 7a, the pressing force F is applied in a concentric shape than the hole 7a. The pressing force F is a force in a direction opposite to the centrifugal force G generated as the rotor 6 rotates, and can firmly fix the permanent magnet 8a.

In addition, since the rivet 12 is fixed to the end plate 13 as shown in FIG. 4, the centrifugal force G can be supported by the end plate 13. Here, the change of the magnetic flux which the permanent magnet 8 makes, and the change of efficiency were examined about the rotor 6 whose hole 7b is located in the outer peripheral side rather than the permanent magnet 8.

The electric motor used for examination is an electric motor with a 1-kw output, 0.19 kg-m of torque (constant), and a rated speed of 5000 rpm. 5 shows magnetic flux density distribution in the electric motor of this embodiment. Fig. 6 shows the difference in the rotational speed-efficiency characteristics between the motor of this embodiment in the case of using a magnetic rivet and a conventional electric motor (see Fig. 6 of JP-A 7-322538) in which the rivet is pushed on the side of the rotating shaft rather than the permanent magnet. Indicates.

5 shows that even if the hole 7a is provided in the outer peripheral side rather than the permanent magnet 8, there is little influence on the magnetic flux density distribution. It is clear from FIG. 6 that efficiency does not deteriorate even if the rivet of a magnetic body is used.

However, if the rivet 12 is not electrically insulated from the rotor core 7, a large overcurrent loop occurs in the direction of the rotational axis of the rotor 6, so that the efficiency is lowered. Therefore, the rivet 12 is preferably electrically insulated from the rotor core 7. The rivet 12 is preferably an insulator or an insulated magnetic body.

The rotor 6 shown in FIG. 7 uses two poles 7b in each of four pole pieces, and uses a pair of magnetic rivets 12 and a non-magnetic rivet 14 in pairs. The rotor 6 is a rotating electric machine that is asymmetrical in the range of one pole, but can be balanced in the entire circumference of the rotor 6.

The center angle (hereinafter referred to as pole piece angle) θ that the pole piece of the rotor 6 is centered on the rotation axis, the center angle (hereinafter referred to as slot pitch angle) τs that the slot pitch is centered on the rotation axis, s, and the slit If the center angle (hereinafter referred to as slit width angle) made around this axis of rotation is represented by S,

θ = n × τs + A × S (n is an integer, A is a constant of 0 ≦ A ≦ 1 depending on the flow of the slot magnetic flux, and the angle is a machine angle). When the slot pitch angle [tau] s is 15 degrees and the slit width angle S is 6.7 degrees, n = 3 and A = 0.7 are the pole piece angles [theta] to 49.7 degrees. In practice, the pole piece angle may be selected within the range of θ = n × τs + A × S ± 1.

In order to clarify the relationship between the waveform of the induced voltage and the pole piece angle θ, the induced voltage waveform when the pole piece angle θ is changed to θ = 54.7, 49.7, 44.7 degrees is shown in FIG. 8. However, the center angle ψ = 88.2 degrees and the slit width angle S = 6.7 degrees made by the permanent magnet 8 about the rotation axis are made constant.

From Fig. 8, the induced voltage waveforms are five mountain-shaped convex waveforms when θ = 54.7 degrees, and five valley-shaped concave waveforms when θ = 44.7 degrees. The closest sine wave to the induced voltage waveform is when θ = 49.7 degrees. In order to quantitatively evaluate the sine wave, if the induced voltage waveform is a sine pie, the peak voltage at 90 degrees of electric angle is √2 times the effective value, so that the waveform variation rate = voltage at 90 degrees of electrical angle / (effective voltage value x√ The value was defined by defining 2). Convex waveforms have a rate of change greater than one, and concave waveforms have a rate of change less than one. As the rate of change approaches 1, the waveform is closer to sinusoidal. The results are shown in FIG.

From Fig. 9, the waveform variation ratio close to 1 is the case where θ = 49.7 degrees, and the superiority of the electric motor having the relationship of θ, τs, and S obtained in this embodiment can be quantitatively evaluated.

Next, in order to clarify the relationship between the waveform of the induced voltage and the center angle ψ made by the permanent magnet 8 about the rotation axis, the induced voltage waveform in the case of changing ψ = 88.2 and 78.2 degrees is shown in FIG. However, the pole piece angle θ = 49.7 degrees and the slit width angle S = 6.7 degrees are made constant. The relationship between (psi) and waveform variation rate is shown in FIG.

It can be seen from FIG. 10 that the shape of the induced voltage waveform hardly changed even when? Was changed. It can be seen from FIG. 11 that the waveform fluctuation rates are almost the same. Thus, it can be seen that ψ does not change the induced voltage waveform.

Finally, in order to clarify the relationship between the waveform of the induced voltage and the slit width angle S, the induced voltage waveform when the slit width angles S = 8.7, 6.7, and 2.7 degrees are shown in FIG. However, the pole piece angle θ = 49.7 degrees and ψ = 88.2 degrees are made constant. 13 shows a relationship between the S and the waveform variation rate.

It can be seen from FIG. 12 that the shape of the induced voltage waveform changes when S changes. It can be seen from FIG. 13 that the waveform fluctuation rate is greatly changed. Therefore, it can be seen that S is closely related to the induced voltage waveform.

In addition, when the slot pitch tau s changes, the induced voltage waveform changes. The induced voltage waveform in the case where the slot pitch tau s = 15, 30 and other conditions are constant for confirmation is shown in FIG. It can be seen from FIG. 14 that the induced voltage waveform changes when the slot pitch tau s changes.

In view of the above, in order to bring the induced voltage waveform closer to the sinusoidal wave, the pole piece angle θ is almost equal to the slot pitch angle τs and the slit width angle S.

It is necessary to have a relationship shown by θ = n × τs + A × S (n is an integer, A is a constant of 0 ≦ A ≦ 1 depending on the flow of the slot magnetic flux, and the angle is a machine angle).

In addition, the constant A showing the effectiveness of the slit width angle S in the variation of the induced voltage waveform varies depending on the strength of the magnet and the slot shape, but when the magnet is ferrite, A = 0.7.

On the other hand, although n, the induced voltage waveform and n,

In the case of 2n × τs + A × Sθ (2n + 1) × τs + A × S (n is an integer),

Become a concave waveform,

(2n + 1) × τs + A × Sθ (2n + 2) × τs + A × S (n is an integer)

In the case of, it becomes a convex waveform.

In the above embodiment, specifically showing as τs = 15 degrees, A = 0.7, S = 6.7 degrees,

4.7θ19.7

19.7 θ 34.7 ...

34.7 θ 49.7 ...

49.7θ64.7 ... becomes a convex waveform.

Since the peak value of the induced voltage increases stepwise when changing from the concave waveform to the convex waveform, a condition in which θ changes from the concave waveform to the convex waveform, that is, the case where n is odd is effective.

As described above, the electric motor configured as described above is powered by an inverter power supply. The so-called 120 degrees which the U phase shifts a 120 degree phase and energizes adjacent stator windings (for example, U1 and U2 of U phase, V1 and V2 of V phase, and W1 and W2 of W phase) of each phase of V phase and W phase. As the energization is performed, a rotor magnetic field generated by the stator 1 is generated, and the rotor 6 rotates by magnetic attraction force and repulsion force.

At this time, the magnetic flux density distribution of the permanent magnet 8 acting on the gap 5 is concentrated in the energizing section 120 degrees larger than the conventional example, so that the motor efficiency is improved. The magnetic flux density distribution of the transmitter of this embodiment is shown in FIG.

FIG. 15 shows a difference in magnetic flux density distribution of the gap portion from the present example and the conventional example in which the magnetic center of the permanent magnet is one point.

It can be seen from FIG. 15 that the maximum magnetic flux density of the gap portion of the present invention is 0.485 tesla and about 1.3 times the magnetic flux density of 0.375 tesla of the permanent magnet. However, in the conventional example, since it is about 1.1 times, it turns out that this invention is superior to the conventional example. In addition, it can be seen that the magnetic flux density of the non-energized section of the electric motor of the present embodiment is smaller than the magnetic flux density of the non-energized section of the conventional example and is concentrated in the energized section (the electric angle of 30 degrees to 150 degrees in FIG. 15) having a magnetic flux of 120 degrees. have.

6 shows a comparison of the motor efficiency between the present embodiment and the conventional example. In FIG. 6, in this embodiment and the prior art example, control is carried out in a current phase in which the motor efficiency is maximum. It can be seen from FIG. 6 that the present embodiment is particularly effective in improving efficiency at low rotational speeds.

(2nd Example)

16 shows a permanent magnet rotary electric machine as a second embodiment of the present invention. In this embodiment, a V-shaped permanent magnet 8a having two magnetic centers is used. The recessed part of the permanent magnet 8a is arrange | positioned so that it may become the stator 9 side.

Also in this case, the magnetic flux density distribution of the permanent magnet 8 acting on the gap is larger than that of the conventional example and is concentrated in a 120 degree energization section, thereby improving the motor efficiency. 6 shows a comparison of the motor efficiency between the present embodiment and the conventional example. It can be seen from FIG. 6 that, similarly to the case of the first embodiment (FIG. 1), the effect of efficiency improvement is particularly great at a low rotational speed. That is, the shape which can obtain the generated magnetic flux maximum of a permanent magnet among the determined rotor outer diameter and shaft length becomes high efficiency.

In addition, in the present invention, in a case other than 120-degree energization, for example, 180-degree energization may be used, and the number (number of poles) of the permanent magnets may be other than four poles. The number of slots of the stator may also be other than 24. The permanent magnet 8 may be other than a ferrite magnet, or may be a part of an ellipse as long as it is a bow. The present invention may be modified in various ways without departing from the scope of the present invention.

Here, the motor using the bow-shaped permanent magnet 8 described in the first embodiment is compared with the motor using the V-shaped permanent magnet 8a of the present embodiment.

The torque of the permanent magnet rotary electric machine in which the permanent magnet is embedded in the rotor iron core 7 may be represented by Equation 2 in addition to Equation (1).

T: torque of motor, ψ: magnetic flux by permanent magnet, Lq: q-axis inductance

Ld: d-axis inductance, Iq: q-axis winding current, Id: d-axis winding current

In Equation 1, the first term is a torque caused by the main magnetic flux of the permanent magnet, and is proportional to the surface area of the rotating shaft side of the permanent magnet. The second term is the reluctance torque caused by the auxiliary magnetic poles of the iron cores between the adjacent magnets, and is proportional to the distance between the adjacent magnets. The torque of the surface magnet electric motor in which a permanent magnet is disposed on the surface of the rotor iron core 7 is only claim 1 and does not have the second claim. The torque of the magnet-embedded electric motor as in the first embodiment and the present embodiment has both of claims 1 and 2, so that the torque is higher than that of the surface magnet electric motor.

When comparing the electric motor using the bow-shaped permanent magnet 8 with the pole-type angle θ of the rotor iron core and the motor using the V-shaped permanent magnet 8a, the permanent magnet ( 8) the surface area of the rotating shaft side is large. Therefore, since the main magnetic flux which a permanent magnet produces by the electric motor side using the bow-shaped permanent magnet 8 is large, the torque by Claim 1 is large.

The distance between adjacent magnets is large with the electric motor using the V-shaped permanent magnet 8a. Therefore, the reluctance torque according to claim 2 is large in the motor using the V-shaped permanent magnet 8a. However, reluctance torque is hardly generated when 120 degree electricity supply is conducted. Therefore, when 120 energization is performed, the electric motor using the bow permanent magnet 8 has a large torque.

FIG. 17 shows an example where the magnetic center is three points a, b, and c, and FIG. 18 shows an example where five points are a, b, c, d, and e. In this embodiment, by increasing the magnetic center, the area of the permanent magnet generating magnetic flux can be increased, the magnetic flux effect of the magnetic flux can be increased, and the magnetic flux density of the gap portion can be made higher than the magnetic flux density of the magnet. However, since the iron loss increases, an effective section exists in the value of the gap magnetic flux density / magnetic magnetic flux density.

19 shows the relationship between the gap magnetic flux density / magnetic magnetic flux density and the efficiency when the rotation speed is 1000, 3000, and 5000 rpm. From Fig. 19, when the gap magnetic flux density / magnet magnetic flux density is larger than 1.2, the case of 3000 rpm is higher than that of 5000 rpm, and the tendency of efficiency deterioration with increasing iron loss starts to appear. If the gap magnetic flux density / magnet magnetic flux density is greater than 1.5, the efficiency starts to decrease despite the large number of revolutions. Therefore, the ratio of the gap magnetic flux density / magnetic magnetic flux density is preferably 1.2 to 1.5.

FIG. 20 shows the relationship between the number of magnetic centers and the efficiency when the rotation speeds are 1000, 3000, and 5000 rpm. It can be seen from FIG. 20 that the magnetic surface is increased and the magnetic flux is concentrated as much as the magnetic center is, so that the efficiency is increased. However, since the same stator 1 is used, it is most efficient when the magnetic center is two points in the case of high rotational speed by the influence of iron loss.

(Third Embodiment)

21 shows an example in which the permanent magnet electric motor of the present invention is applied to a scroll compressor for an air conditioner. First, the overall configuration will be described.

In the scroll compressor shown in FIG. 21, a pump portion (compression mechanism portion) is disposed in an upper portion of the hermetic container 21, and an electric motor portion is stored in a lower portion thereof. The pump part has the fixed scroll 22, the revolving scroll 23, the frame 24, and the Oldham ring 31 as main components. The suction pipe 32 connected to the external cycle is press-fitted into the suction port 27 of the fixed scroll 22.

The compression chamber 26 is formed by the fixed scroll 22 and the revolving scroll 23.

The eccentric portion 25a of the crankshaft 25 is rotatably fitted in the boss portion of the revolving scroll. In the groove of the plywood portion and the groove (not shown) of the frame 24, the Oldham ring 31 is arrange | positioned so that sliding is possible. The frame 24 is provided with a seat surface for supporting the plywood of the revolving scroll 23, a surface on which the Oldham ring 31 slides, and a thrust surface for supporting the crankshaft 25 and the spindle support.

Moreover, the frame outer peripheral part is fastened by the fixed scroll 22 and the bolt 33, and the outer peripheral side is fixed to the airtight container 21 by spot welding. A rotor 30 constituting an electric motor is attached to the crank shaft 25. The stator 29 constituting the electric motor is fixed in the sealed container 21. 36 is a bearing supporting the lower part of the crankshaft 25.

When the permanent magnet electric motor of the present invention is applied to a scroll compressor, since the motor efficiency is good, heat exchange can be performed with high power efficiency.

The permanent magnet rotary electric machine described in the above embodiment, in any case, is a permanent magnet rotary electric machine of inner rotation in which the stator surrounds the rotor. However, you may apply this invention to the permanent magnet rotary electric machine of the outer rotation which a rotor encloses a stator. When the permanent magnet is placed on the outer rotor such that the pole piece angle θ, the slot pitch angle τs and the slit width angle S are in a relationship of θ = n × τs + A × S, the permanent magnet rotary electric machine of the outer rotation is subjected to an induced voltage. It is possible to make the waveform close to the sine wave, facilitate the sensorless control, and increase the driving torque.

According to the permanent magnet rotary electric machine of the present invention, it is possible to increase the magnetic flux acting in the gap as much as possible, and also by concentrating on the conduction section of 120 degrees, miniaturization of the rotor or high efficiency as shown in FIG. Exert.

Further, according to the permanent magnet rotary electric machine of the present invention, since the punching hole for fixing the rotor laminated iron core is on the gap side than the magnet, the pressing force for fixing by the rivets and the like becomes opposite to all centrifugal forces.

In addition, the structure supporting the centrifugal force as a structure supporting the rivet and the end plate in addition to the bridge portion can provide a permanent magnet rotary electric machine having strong permanent magnet fixing means.

According to the permanent magnet rotary electric machine of the present invention, the pole piece angle θ of each permanent magnet of the rotor is approximately equal to the slot pitch angle τs and the slit width angle S,

θ = n × τs + A × S (n is an integer, A is a constant of 0 ≦ A ≦ 1 depending on the flow of magnetic flux in the slot portion, and angle is a machine angle). It has a close effect, facilitates sensorless control, increases the drive torque of the electric motor, and enables miniaturization or improved drive efficiency.

Claims (11)

In a permanent magnet rotary electric machine comprising a stator and a rotor in which a plurality of permanent magnets are embedded in the rotor core, Each of the permanent magnets has a plurality of bow-shaped shapes in a cross section perpendicular to the rotation axis, has a plurality of magnetic centers, and the bow-shaped recesses are arranged so as to face the stator direction. Permanent magnet rotary electric machine. The permanent magnet rotary electric machine according to claim 1, wherein the permanent magnet is arranged so that the magnetic flux is concentrated in a 120 degree section at an electrical angle. The permanent magnet rotary electric machine according to claim 1, wherein the maximum magnetic flux density of the gap generated by the permanent magnet is 1.2 to 1.5 times the magnetic flux density of the permanent magnet. 2. The pole piece angle (mechanical angle) θ of the rotor is approximately equal to 2 when the slot pitch angle (machine angle) of the stator is τs and the slit width angle (machine angle) of the stator is S. , θ = n × τs + A × S (where n is an integer and A is a constant of 0 ≦ A ≦ 1 depending on the flow of magnetic flux in the slot portion). The pole piece angle (machine angle) θ of the rotor according to claim 1, wherein when the slot pitch angle (machine angle) of the stator is τs and the slit width angle (machine angle) of the stator is S, θ = n × τs + A × S ± 1 (where n is an integer and A is a constant of 0 ≦ A ≦ 1 depending on the flow of magnetic flux in the slot portion). 2. The pole piece angle (mechanical angle) θ of the rotor is approximately equal to 2 when the slot pitch angle (machine angle) of the stator is τs and the slit width angle (machine angle) of the stator is S. , θ = n × τs + A × S (n is an integer, A is a constant of 0 ≦ A ≦ 1 depending on the flow of magnetic flux in the slot portion), and the cross-sectional shape of each permanent magnet of the rotor is a magnetic center. The permanent magnet rotary electric machine characterized in that it forms so that it may become linear as at least two points, and these permanent magnets are magnetically continuous. The permanent magnet rotary electric machine according to claim 1, wherein the distance between adjacent permanent magnets is minimum in the middle portion of the rotor in the radial direction and increases from the middle portion toward the outer circumference. In a permanent magnet rotary electric machine comprising a stator and a rotor in which a plurality of permanent magnets are embedded in the rotor core, the slot pitch angle (machine angle) of the stator is τs, and the slit width angle of the stator (machine When the angle) is S, the pole piece angle (machine angle) θ of the rotor is almost θ = n × τs + A × S (n is an integer and A is a constant of 0≤A≤1 depending on the flow of magnetic flux in the slot portion). In a permanent magnet rotary electric machine comprising a stator and a rotor in which a plurality of permanent magnets are embedded in the rotor core, the slot pitch angle (machine angle) of the stator is τs, and the slit width angle of the stator (machine When the angle) is S, the pole piece angle (machine angle) θ of the rotor is almost θ = n × τs + A × S ± 1 (n is an integer, A is a constant of 0≤A≤1 depending on the flow of magnetic flux in the slot portion), the permanent magnet rotary electric machine characterized by the above-mentioned. 9. A permanent magnet rotary electric machine according to claim 8, wherein n is odd and A is about 0.7. The permanent magnet rotary electric machine according to claim 8, wherein the rotor is rotated by energizing the stator windings of each phase by 120 degrees at an electrical angle.