JPS60197148A - rotating electric machine - Google Patents

Abstract

PURPOSE:To obtain a rotary electric machine which has less cogging torque by disposing a gap between adjacent permanent magnets within the width of a nonmagnetic portion formed between poles. CONSTITUTION:A 4-pole 3-phase motor 1 has an armature 2 and a rotor 3, and the armature 2 has a core 7 including slots S of the opening of the inner periphery and a winding 8. The slots S are formed of the opening 12 and the toothed portions 13 at both sides. The rotor 3 has permanent magnets 4 on the outer peripheral surface of the rotor core 11, and a gap 5 interposed between the side edges 6 of the magnets 4 is formed in parallel with a rotating axis 10. In this case, a nonmagnetic portion 9 having a width is formed between the poles of the magnets 4, and the gap 5 is disposed within the portion 9. Thus, the width N of the portion 9 can suppress the occurrence in the abrupt variation in the polarity of the adjacent magnets 4 at the position between the opening 12 and the toothed portion 13.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to rotating electric machines, particularly those having a permanent magnet in a mover.

[Background of the invention]

Conventional rotating electrical machines, such as commutatorless motors, are widely used because they are easy to maintain. An example of this is its recent application to servo motors. An important condition for the electric motor used as this servo motor is that rotational pulsation, that is, cogging torque, is small, and precise positioning is particularly desired in the low-speed rotation range.

However, conventionally developed non-commutator motors have the drawback of large cogging torque.

The cause of this? In order to find out, the inventors conducted extensive research and found the following.

A conventional rotor is constructed by arranging a plurality of permanent magnets da-Ad'f around the outer periphery of a rotor core 11, as shown in FIG. These permanent magnets 4a to 4d have an IIT surface shape of a circular arc or a substantially circular arc for ease of manufacture, and the side edges 6 of the mutually adjacent permanent magnets 4a to 4d are parallel to the rotation axis 10. It is arranged like this.

Generally, ferrite magnets are widely used as the permanent magnets 4a to 4d because they have excellent magnetic properties and are inexpensive, but these ferrite magnets have a drawback of poor dimensional accuracy. A permanent magnet 71 made of such a magnetic material. ! , -a6 are used by forming a gap 5 between adjacent side edges 6.6.

FIG. 2 is a developed view showing the permanent magnets 4a to 4dv in FIG. 1.

In the figure, the permanent magnets 4a to 4d are alternately magnetized with 51CN poles and 8 poles so that the polarities are mutual. It is known that skewing the inclination of this magnetization with respect to the rotation axis 10 is good for reducing cogging torque, and the non-magnetized portion 9 between the magnetic poles is also tilted by an angle Q with respect to the rotation axis 10. Indicates the condition.

FIG. 3 shows the magnetic flux distribution of the permanent magnets 4a to 4d in FIG. 2, where the solid line a represents the magnetic flux density on the a-ai line, and the broken line S represents the magnetic flux density on the bb line. From this reason, it can be seen that at 5K, the magnetic flux distribution shows a portion where the magnetic flux density decreases due to the gap 5. This drop is equivalent to the existence of an equivalent non-skew stator slot on the rotor even though it is skew magnetized.Next, the rotor with such a magnetic flux distribution is Rotate within [, Consider the case. The lowering portion and the transition portion 8 between the magnetic poles move while sequentially intersecting the slot opening and tooth portion of the armature core. Since there is a difference in magnetic resistance between the opening and the teeth, it has been found that pulsation of rotational force, that is, cogging torque, occurs due to the interaction between this difference in magnetic resistance and the lowering portion and the transition portion 8.

[Purpose of the invention]

The object of the present invention is to solve the above-mentioned drawbacks and provide a rotating electrical machine with low cogging torque.

[Summary of the invention]

The present invention is characterized by a fixed armature having a multi-phase armature winding, and a movable armature that alternately vibrates a plurality of permanent magnets with different polarities in the movable direction, and is magnetically coupled to the fixed armature. In a rotating electric machine, the gap formed between adjacent permanent magnets is filled with non-magnetic material.
The gap is located within the width of the non-magnetized portion located between the polarities of the permanent magnet, and the magnetic flux distribution of the rotor KyAr
The objective is to reduce the cogging torque by eliminating the drop caused by WK.

[Embodiments of the invention]

+3 Hereinafter, one embodiment of the present invention will be described with reference to FIGS. # to P.

The second diagram shows the use of the present invention in a four-pole, six-phase motor. The electric motor, indicated as a whole by 1, consists of an armature 2 and a rotor 3 as a movable element. The armature 2 has a zero armature winding composed of an iron core 7 and an armature winding 8 having slots 81 to S24 (however, (9) is omitted for S7 to S818) opening on the inner circumferential surface. The windings for one pole each forming one phase U of the line 8 are installed in the slots S1, 86, 87, 812, 813, 818, 819, and 82 AVC, and the integrals for each of the phases are 85 to 810, 811. ~S16°817~
822, 823 to S4, and the windings for one pole of the W phase are 89 to s1d, 815 to 8'20, 82.
1 to 82.83 to S8.

These slots) 81 to B24 provided in the iron core 7 are formed by an opening 12 into which the electric machine prewinding 111i[8 is inserted, and teeth 13 located on both sides of this opening 120 to form a magnetic path.

The rotor 5 located inside the armature 2 has permanent magnets 4a to 4d of the same number as the number of poles on the outer peripheral surface of the rotor core 11, and are arranged so that the polarities are alternately different. These permanent magnets 4a to 6d are attached to the rotating shaft #10 for ease of manufacture.
The cross-sectional shape that is perpendicular to the curve is in the shape of a circular arc or a substantially circular arc. 5th south is 0 permanent magnet 4 which is a perspective prisoner of rotor 3
The gap 5 sandwiched between the side edges 6, 6 of a to 4d is the rotation axis M10 &
It is parallel to C.

Considering the dimensional accuracy of the permanent magnets 4a to 4d and workability during installation, this gap 5 is usually about 0.5 to 2-2, and is filled with a non-magnetic material such as aluminum, zinc, zinc alloy, etc. It may simply be space. In addition, rotor 3
The outer periphery of the magnet is generally covered with a non-magnetic stainless steel plate, aluminum plate, resin, etc., but is not shown in the figure.

The non-commutator motor having such a configuration has a position detector that detects the rotational position of the rotor 30, and upon receiving a signal from the position detector, the armature winding 8V is made conductive in sequence by the conduction control means. Electric advance volume #i! It is operated by the interaction between the current of 8 and the magnetic flux of the permanent magnets di to 4d arranged in the rotor 3.

In this operation, if we look at the flow of magnetic flux of the permanent magnet 4a, we can see that it passes through the air gap G to the iron core 7 as shown by the broken line in the figure.
It flows through the tooth portion 13 and the back portion 14 to the adjacent permanent magnet 4b of the other polarity. (The magnetic flux to the permanent magnet 4d side is omitted.) Since the toothed portions 13 and the openings 12 of the throwers (thrower) 81 to 52jl provided on the iron core 7 have different magnetic resistances, the permanent magnets 4a and 4
The magnetic flux at the magnetic pole tip b tends to flow to a portion with low magnetic resistance, that is, to avoid the opening s12 and flow to the tooth portion 13.

For this reason, the torque tends to vary depending on the position between the magnetic poles of the permanent magnets da, 4b, da, and AeL, and the relative position between the opening 12 and the teeth 13 of the slot 8 facing thereto. However, the rotor of this example is the sixth rotor.
As the permanent magnets 4a to 4d are shown expanded in the figure, a non-magnetized portion 9 having a width N is provided between the magnetic poles of these permanent magnets 4a to 4d, and a permanent magnet is provided within this non-magnetized portion 9. Magnet 4a
A gap 5 between .about.4d is positioned.

Therefore, as shown in the seventh section, the magnetic flux distribution of the permanent magnets 4a to 4d does not show a drop part due to the gap 5, and due to the width N of the non-magnetized part 9, the magnetic flux suddenly changes between different magnetic poles. The changing portions E are separated by a width N.

8A to 8C show the flow of magnetic flux of the permanent magnets +aa and 4d depending on the rotational position of the rotor 3.

As can be seen from this figure, the magnetic flux flows more easily to the teeth #13 and 15', which have smaller magnetic resistance than the opening 12, or the width N of the non-magnetized part 9 is substantially larger than that of the adjacent permanent magnets aa, ab. This prevents a sudden change in polarity from occurring between the opening 12 and the teeth adjacent to the opening 12.

Therefore, an electric motor with small cogging torque can be obtained.

In another embodiment of the present invention, as shown in FIG. 9, the permanent magnets 4a to 4d are skew-magnetized at an angle of 0 with respect to the rotational axis 10, and the gap 5 is used as a non-magnetized portion between the magnetic poles. 9 width N internal pressure position K.

tOf Figure 9 shows the magnetic flux distribution in Figure 8, where the solid line a is a-
On am, break #b indicates the magnetic flux density of &l+j on b-bll.

As can be seen from this figure, the magnetic flux distribution lines a and b are shifted by α in the rotation direction due to the skew, and there is a gap 5 between the magnetic flux bands.
There is no influence.

Therefore, during operation, the magnetic pole ends of the permanent magnets 4a to 4d pass through the opening 12 and the toothed portion 13 of the iron core 7 sequentially in the direction of the rotational axis 10 with time shifts.

Therefore, cogging torque can be further reduced.

Note that the present invention is not limited to the above embodiments, and various modifications are possible.

For example, the movable element can be used not only for rotary motion, but also for linear motion, and for movable elements in which the fixed armature and the movable element are arranged facing each other in the axial direction. be.

Furthermore, the present invention is applicable not only to electric motors but also to generators, and in the generator, harmonic components of the output voltage waveform can be reduced.

〔Effect of the invention〕

According to the present invention, the armature includes an armature in which an armature winding is housed in a slot provided in an iron core, and a mover magnetically coupled to the armature, and the mover has a plurality of permanent magnets. In this case, the gap between adjacent permanent magnets is located within the width of the non-magnetized part between the magnetic poles.
A rotating electrical machine with less cogging torque can be obtained.

[Brief explanation of drawings]

Figure 4 3 3 3 Nose 1Ot211 (a an

Claims (1)

[Claims] 1. An armature having a plurality of phases of armature windings in slots, and a plurality of permanent magnets having alternately different polarities in the movable direction, and magnetically coupled to the armature. and a mover having a gap between the adjacent permanent magnets, characterized in that the gap is located within the width of a non-magnetized portion provided between the magnetic poles of the permanent magnets. rotating electric machine. 2. The rotating electric machine according to claim 1, wherein the permanent magnet is magnetized in a skew with respect to the rotation axis. 3. The rotating electric machine according to claim 1 or 2, wherein the movable element rotates. 4. The rotating electric machine according to claim 1 or 2, wherein the movable element moves linearly.