JPS5852426B2 - Electric motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric motor having a structure in which magnetic poles forming an armature core are opposed to permanent magnets forming a multi-pole magnetized rotor.

Generally, in a motor having an armature core with one magnetic pole and windings thereon, as the number of permanent magnet poles increases, the number of magnetic poles and the number of windings also increase.

As a result, when the number of poles is large, the number of winding steps increases and manufacturing becomes complicated, making it difficult to increase the number of poles of a permanent magnet.

Therefore, for example, when speed control is performed using the back electromotive force induced in the winding, the ripple frequency included in the back electromotive force is low, so the cutoff frequency of the ripple removal filter is set low. As a result, there was a problem that the control gain could not be increased.

In order to solve such problems, the number of windings was reduced by increasing the opposing pitch of the magnetic poles for the winding of the armature core to an odd number of 3 or more times the pitch of one magnetic pole of the permanent magnet. An electric motor having a structure as illustrated in FIG. 1 has been proposed (not publicly known).

To explain this further, the permanent magnet 2 attached to the rotor 1 is an annular magnet magnetized with 10 poles at equal angular intervals (36 degrees) or approximately at equal angular intervals t.

The armature core 3 has three main magnetic poles 4a, 4b, 4 for windings.
c and three auxiliary magnetic poles 5a, 5b5c.

Main magnetic pole 4a for each winding. 4b, 4c) These are one winding 6a, 6b, respectively.

6c is wrapped.

The centers of the magnetic poles 4a to 4c 5a to 5c are arranged at equal angular intervals (600) or at approximately equal angular intervals,
The effective opposing pitch of the main magnetic poles 4a to 4c for each winding through which the magnetic flux from the permanent magnet 2 flows in and out is 1 of the permanent magnet 2.
3 times the magnetic pole pitch (108°) is approximately equal to approximately 109
．． 1 degree, and the effective opposing pinch of each of the auxiliary magnetic poles 5a to 5c is about 10.9 degrees.

Further, in the portions of the main magnetic poles 4a to 4c for each winding that face the magnetized surfaces of the permanent magnets 2, there are auxiliary grooves 7 having almost the same magnetic effect as the grooves 8 between the magnetic poles. Nine pieces are provided in each direction perpendicular to the plane of the drawing.

The entire groove of the armature core 3, consisting of the auxiliary groove 7 and the groove 8 between the magnetic poles, is spaced at equal angular intervals or approximately at equal angular intervals (10 out of 3600/33) with respect to the center 0 of the armature core 3. ．．
9°) is placed.

The effect of the auxiliary groove 7 will be described later.

The main magnetic poles 4 a , 4 b z 4 c for winding are divided into three independent phases due to their relative positional relationship with the magnetic poles of the permanent magnet 2.

The magnetic flux flowing into the windings 6a, 6bt6c is equal to the magnetic flux flowing from the permanent magnet 2 from the tips of the winding magnetic poles 4a, 4b, 4c, so the windings 6a, 6b, 6c are independent three-phase (this What I know is this.

Therefore, if the rotational position of the permanent magnet 2 is detected by a magnetically sensitive element such as a Hall element, and the windings carrying a constant current are sequentially switched by a semiconductor switch such as a transistor, the rotor 1 is moved in the same direction. It can be rotated.

Next, the cogging force of the electric motor and the effect of the auxiliary groove 7 illustrated in FIG. 1 will be explained.

Generally, cogging force is generated when the magnetic energy stored in the magnetic field between the permanent magnet 2 and the armature core 3 changes depending on the rotational position I of the armature core.

Since magnetic energy is a quantity related to the square of the magnetic flux density, the permanent magnet 2 has a magnetic fluctuation of its harmonic component, with one magnetic pole pitch as a fundamental period.

Therefore, with one magnetic pole pitch of the permanent magnet 2 as the fundamental period,
It is only necessary to consider the magnetic variation of the armature core 3, and generally speaking, if the amount of variation is reduced, the cogging force will be reduced.

Magnetic fluctuations in the armature core 3 are caused by the grooves 8 between the magnetic poles and the auxiliary grooves 7, and the magnetic fluctuations due to these grooves correspond to the permeance (reciprocal of magnetic resistance) seen from each point on the surface of the permanent magnet 2. Locational variation (expressed by this)

This will be explained with reference to FIG.

FIG. 2A shows the magnetic fluctuation caused by the groove 8 between the magnetic poles.

When the fluctuations (broken lines) of the six grooves around the entire circumference are combined, there are three valleys as shown by the solid lines in the figure.

Figure 2B shows the magnetic composite fluctuation when the auxiliary groove 7 is provided.
is shown by a solid line.

Each broken line in the figure indicates a variation due to each groove in the auxiliary groove 7 or the groove 8 between the magnetic poles.

The auxiliary groove 7 and the groove 8 between the magnetic poles have almost the same magnetic effect, and the 33 grooves are 1/33 of the pitch of one magnetic pole.
They are arranged with a phase difference of .

That is, when the basic period is one magnetic pole pitch of the permanent magnet 2, the phase of the auxiliary groove 7 is different from the phase of the groove 8 between the magnetic poles (here, the phase of all the grooves is made to be different). ).

As a result, the magnetic variation of the armature core of the motor shown in FIG. 1 becomes as shown by the solid line in FIG. 2B.

If we compare this with the case where the auxiliary groove 7 is not provided, that is, the solid line in Fig. 2A, the fluctuation frequency (the reciprocal of the pitch between the valleys of the magnetic fluctuation) becomes higher and the magnitude decreases. ing.

Therefore, the amount of magnetic fluctuation of the armature core 3 is reduced,
The cogging force decreases.

Additionally, in general, when the frequency of the magnetic variation of the armature core 3 is high, the magnitude of the corresponding component of the magnetic variation of the permanent magnet 2 becomes small, and the interaction between the two becomes smaller. Since the cogging force becomes smaller, the cogging force in this example becomes even smaller.

In addition, more specific data in FIG. 2 is as follows.

In Figure 2A, the distance between the two peaks on the dashed line: 2.7 mm (30/11 in the middle).The distance between the three peaks: 30. In Figure 2B, the number of peaks on the dashed line: 33.The distance between the peaks on the dashed line: 2.7 tomo (middle school 90/33) Number of peaks on the solid line: 33 Interval between peaks in the solid line = 2.7 tomo (middle school 90/33) From the above explanation, it is clear that the electric motor disclosed in FIG. teeth,
It is advantageous in that it is simple to manufacture due to the small number of windings, and the cogging force is small due to the effect of the auxiliary groove.

However, since the effective opposing pitch of the magnetic poles for the winding is an integer multiple of 3 or more than the pitch of one magnetic pole of the permanent magnet, the maximum value of the magnetic flux flowing into the magnetic pole for the winding is at most from one magnetic pole. It's just magnetic flux flowing in, and the utilization rate of the magnetic poles is poor.

In other words, the electric motor has poor efficiency.

The present invention provides an efficient electric motor that is further improved in these respects.

Hereinafter, the present invention will be explained based on illustrated embodiments.

FIG. 3 is a block diagram of a main part of an embodiment of the present invention, and FIG. 4 is a schematic plan development view thereof.

In Fig. 3, the permanent magnets 2 attached to the rotor 1 are magnetized with alternating north and south poles at equal pitch intervals (36°) or approximately at equal pitch intervals. It is an annular magnet, and is similar to the case of the electric motor shown in FIG.

6 main magnetic poles 12 al, 12a2゜12b1, 12
Main magnetic pole structure 11 having b2, 12c1, 12C2
and six auxiliary magnetic poles 14a.

Auxiliary magnetic pole arrangement 13 having 14b, 14c, 14d, 14e, 14f and their magnetic pole arrangement 11 and 13
An armature core is constituted by a connecting magnetic body 15 that magnetically couples the two.

The main magnetic pole structure 11 and the auxiliary magnetic pole structure 13 can be constructed by, for example, bending an iron plate.

Furthermore, a winding 16a is wound around the base of the two main magnetic poles 12a1 and 12a2, where the magnetic fluxes flowing in and out of the main magnetic poles are focused.

Similarly, the windings 16b are connected to the main magnetic poles 12b1 and 12b2.
Main magnetic poles 12c1 and 12C2# windings 16c are provided.

The main magnetic poles 12al, 12a2.12bt, 12b
212C, 12C2 and auxiliary magnetic poles 14a to 14c
The part I facing the permanent magnet 2 is the groove 17 between the magnetic poles.
An auxiliary groove 18 is provided which has almost the same effect as the magnetic pole.
0'/33 (10.9°) (the angular interval is constant when looking from the center of the armature core to the middle part of the valley groove).

This is similar to the electric motor shown in FIG.

In addition, FIG. 4A shows the distribution of baked rice density on the surface of the permanent magnet 2, and B- in the same figure shows the main magnetic pole 12a1.12a2+1.
2bt, 12b212c1, and 12C2; and an auxiliary magnetic pole structure 13 including auxiliary magnetic poles 14a to 14f. FIG.

The magnetic fluxes interlinking with the windings 16a, 16b, and 16c have a phase difference of 2/3 of one magnetic pole pitch (36°) in terms of rotation angle.

Therefore, if the rotational position of the permanent magnet 2 is detected by, for example, a magnetically sensitive element and a semiconductor switch is used to switch and control the windings that conduct a constant current, the rotor 1 can be rotated in the same direction.

As is clear from FIGS. 3 and 4, in this embodiment, the auxiliary magnetic poles are arranged between the main magnetic poles so that unnecessary magnetic flux does not interlink with the windings.

As a result, the maximum value of the magnetic flux interlinking with the winding is approximately equal to the two poles of the permanent magnet, and the efficiency of the motor is improved.

Further, by providing the auxiliary groove 18, the cogging force of the motor of this embodiment is significantly reduced by E, as in the motor of FIG.

That is, when one magnetic pole pitch of the permanent magnet 2 is taken as the basic period, the phase of the auxiliary groove 18 is made to be different from the phase of the groove 17 between the magnetic poles, and the magnetic field of the armature core when the auxiliary groove 18 is not provided. By canceling out the magnetic variation E (the variation caused by the groove 17 between the magnetic poles) by the magnetic variation E caused by the auxiliary groove 18, the composite magnetic The variation is reduced by providing the auxiliary groove 18.

Therefore, the electric motor of this embodiment has a small cogging force and is highly efficient.

In this embodiment, the frequency of the magnetic fluctuations resulting from the synthesis of the armature core is higher than the frequency of the magnetic fluctuations due to the grooves between the magnetic poles, so the cogging force is considerably small.

In order to increase the frequency of the composite magnetic variation, auxiliary grooves 18 having almost the same magnetic effect as the grooves 17 between the magnetic poles are provided, and the entirety of these grooves is aligned with respect to the center of the armature core. The grooves are arranged at equal angular intervals E, and the total number of grooves (33 pieces) is made different from an integral multiple of the number of magnetic poles (10 pieces) of the permanent magnet 2. Care is taken so that the phases of the valley grooves are as different as possible (in this example, the phases of all the grooves are different).

As a result, the frequency of the composite magnetic fluctuation can be increased stably and reliably, and the cogging force of the motor of this embodiment can be reduced by a large width i.

In the embodiment shown in FIGS. 3 and 4, the windings 16a to
16c on each main magnetic pole 12at.

The effective opposing pitch of 12a2, 12b1, 12b2, 12C1, 12c2 and the effective opposing pinch of the auxiliary magnetic poles 14a to 14f located between these main magnetic poles are equal to one magnetic pole pitch of the permanent magnet. Or, if they are made approximately equal, the maximum value of the magnetic flux interlinking with each winding 16a to 16c will be larger.

In other words, efficiency can be further improved. Such an embodiment is shown in FIG.

That is, FIG. 5 is a schematic plan development view of another embodiment of the present invention.

In the figure, A represents the distribution of the magnetic poles and surface magnetic flux density of the permanent magnet 2, and B represents the arrangement relationship of the main magnetic pole, auxiliary magnetic pole, and auxiliary groove.

In contrast to the permanent magnet 2, six main magnetic poles 22al, 22a2, 22b have an opposing pitch of approximately one magnetic pole pitch.
,.

A main magnetic pole structure 21 having 22b2, 22c0, 22c2, three auxiliary magnetic poles 24a, 24b, 24c having an opposing pitch of approximately 1 magnetic pole pitch, and 1/3 thereof.
Three auxiliary magnetic poles 24d, 24e with an opposing pitch of
, 24f are arranged.

The main magnetic pole structure 21 and the auxiliary magnetic pole structure 23 are magnetically coupled as in the embodiment shown in FIG. 3, and constitute an armature core.

A winding 26a is wound around the main magnetic poles 22a1 and 22a2I, a winding 26b is wound around the main magnetic poles 22b and 22b2, and a winding 26c is wound around the main magnetic poles 22c1 and 22c2.

Since the operation of this embodiment as an electric motor is the same as that of the embodiments shown in FIGS. 3 and 4, the explanation here will be omitted, and the cogging force will be explained.

The grooves a1 to a4 between the magnetic poles have a relative positional relationship with the magnetic poles of the permanent magnet 2 (phase when one magnetic pole pitch is the basic period) f
Similarly, the grooves b1 to b4 between the magnetic poles
and c1 to c4 are also in phase.

In addition, grooves a 1 to a 4, grooves b1 to b4, and groove C4''-'
There is a phase difference with C4 of 1/3 of one magnetic pole pitch.

These grooves a1 to a4. b1-b4. FIG. 6 AI shows the magnetic fluctuations due to c1 to c4.

On the other hand, the main magnetic poles 22a1 to 22c2 and the auxiliary magnetic pole 24a
~ One auxiliary groove (or slit) d1~d3, e1~e3, fl~ in the center part of ~24c, respectively
f3 is provided.

These bucket-shaped grooves IcJ and magnetic itb+ are shown in Figure 6B.
IC is shown.

Therefore, the amount of change in the synthetic leather is as shown in Figure 6-C, and compared to the case without auxiliary grooves [Figure 6A], the amount of fluctuation is smaller.
Furthermore, the fluctuation frequency (the reciprocal of the pitch between the troughs of the magnetic fluctuation) also increases.

As a result, the cogging force becomes smaller. Example E As shown, the effective opposing pinch of each main magnetic pole with windings and the effective opposing pinch of the auxiliary magnetic pole located between these main magnetic poles are defined as one magnetic pole of the permanent magnet. If the pitch is equal to or approximately equal to the pitch, an efficient electric motor will be obtained.

Furthermore, the torque ripple is reduced, resulting in an electric motor with less torque fluctuation.

Further, even if the entire groove consisting of the groove between the magnetic poles and the auxiliary groove is not arranged at equal angular intervals with respect to the center of rotation, the cogging force can be reduced by providing the auxiliary groove.

In general, the relative positional relationship (1 If the magnetic fluctuations caused by the grooves between the magnetic poles are offset by the magnetic fluctuations caused by the auxiliary grooves (with respect to the phase when the magnetic pole pitch is the basic period), the magnetic fluctuation of the synthetic skin of the armature core By providing an auxiliary groove, the amount of fluctuation in the amount of vibration is reduced, and the cogging force is also reduced.

In particular, if an auxiliary groove is provided to increase the frequency of fluctuation, the cogging force can be easily reduced.

Furthermore, in each of the embodiments shown in FIG. 3 (FIG. 4) or FIG. 5 of the present invention, the auxiliary magnetic pole provided in the armature core also has the effect of reducing cogging force.

This will be explained. Considering the case where the auxiliary magnetic pole is eliminated, the width of the groove between the magnetic poles formed at that location becomes wider, and the magnitude of magnetic fluctuation becomes larger.

In order to offset the magnetic fluctuations caused by this wide groove with the auxiliary groove, it is necessary to provide a wide and deep auxiliary groove.

As a result, the number of auxiliary grooves provided for the magnetic poles of the armature core is significantly reduced, and not only is it not possible to sufficiently reduce the magnetic fluctuations of the synthetic skin of the armature core, but also the frequency of fluctuations cannot be made very high. Therefore, it is not possible to reduce the cogging force sufficiently.

On the other hand, if the auxiliary magnetic poles are provided at required locations between the main magnetic poles as in the present invention, the grooves formed between the magnetic poles can be made small regardless of the width of the main magnetic poles.

Therefore, the narrow auxiliary groove can provide the same or almost the same magnetic effect as the groove between the magnetic poles.

As a result, it becomes possible to effectively arrange a large number of auxiliary grooves, and the cogging force can be easily reduced.

In the above description, windings were applied to the main magnetic pole structure having an integral main magnetic pole. Even if the pole blocks A, B, and C are each magnetically connected to the auxiliary magnetic pole structure 23 separately, the effects of the present invention can be obtained.

The effects of the present invention can be obtained in the same way even when the auxiliary magnetic pole structure is divided; If the armature core is constituted by the auxiliary magnetic pole structure, the arrangement precision of each magnetic pole and the arrangement of the auxiliary grooves will be improved, and the effect will be stable.

In addition, in the above explanation (in this case, the permanent magnet was used as the rotor and the armature iron core was used as the stator), this relationship may be reversed, and it is not limited to the external type, but the internal type. It goes without saying that the effects of the present invention can be obtained even as a mold, and it is included in the present invention.

Further, although the above description has been made using a three-phase drive type electric motor as an example, the present invention can also be implemented using a general multi-phase drive type electric motor.

Further, the number of main magnetic poles to which windings are applied may be more than two, and the number of main magnetic poles and auxiliary magnetic poles, the number of auxiliary grooves, and their arrangement are limited to the illustrated embodiments only. It goes without saying that the present invention is not limited, and that various modifications can be made without changing the spirit of the present invention.

As is clear from the above explanation and description, the electric motor of the present invention is
The electric motor is easy to manufacture because it has a small number of windings, is efficient because it utilizes the magnetic poles well, and has a small cogging force because of the provision of auxiliary grooves.

Therefore, if an electronic commutator type electric motor for audio equipment is constructed based on the present invention, it is possible to provide a small, lightweight, large torque electric motor at low cost with minimal vibration and torque unevenness.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the main parts of an example of an electric motor that is not known as an improvement on the conventional motor, FIGS. 2A and B are diagrams showing magnetic fluctuations, and FIG. Part configuration diagram, 4th
Figures A and B are diagrams showing the distribution of magnetic flux density and the arrangement relationship of each magnetic pole structure in the embodiment shown in Figure 3, developed in a plane.
Figures A and B are diagrams showing the distribution of magnetic flux density and the arrangement relationship of each magnetic pole structure in another embodiment 1 of the present invention in plan view, and Figures 6A, B, and C are diagrams showing the embodiment of the present invention. It is a figure which shows the magnetic fluctuation part for demonstrating the effect of an example. 1...Rotor, 2...Permanent magnet, 11
, 21... Main magnetic pole structure, 12a1-12
C2, 22a1-22c2... Main magnetic pole, 13
, 23... Auxiliary magnetic pole structure, 14 a-14
f, 24 a~24 f=--auxiliary magnetic pole, 15
......Connected magnetic bodies, 16a to 16c. 26a-26c...Winding, 17...Groove, 18...Auxiliary groove, al-a4. b1-b4.
C1-C4""" groove, d1-d3, el""C3,
f1-f3 - auxiliary grooves.

Claims (1)

[Claims] 1 N poles at equal pitch intervals or approximately equal pitch intervals,
A permanent magnet magnetized with alternating S poles as TCP poles (here P is an even number of 2 or more), and an armature core having a plurality of main magnetic poles and auxiliary magnetic poles arranged opposite to the permanent magnet. , comprising a plurality of armature windings, the main magnetic pole and the auxiliary magnetic pole are located in a non-contact state between the other magnetic pole facing each other, and the armature winding is The permanent magnet is wound around the base of the main magnetic pole to focus magnetic flux flowing in and out of the two or more main magnetic poles, and is attached to at least one of the main magnetic pole and the auxiliary magnetic pole. An auxiliary groove is provided at a position facing the magnet, and the phase of the groove between the main magnetic pole and the auxiliary magnetic pole and the auxiliary groove when one magnetic pole pitch (=36007P) of the permanent magnet is taken as a basic period. By changing the phase of the magnetic poles of the permanent magnet, the magnetic fluctuation caused by the groove between the main magnetic pole and the auxiliary magnetic pole can be reduced by the magnetic fluctuation caused by the auxiliary groove. An electric motor characterized in that the magnetic fluctuation of the synthetic skin of the armature core is reduced by canceling it out. 2. The effective opposing pitch of each main magnetic pole around which the armature winding is wound (and the auxiliary magnetic pole located between these main magnetic poles) is equal to one magnetic pole pitch of the permanent magnet, or The electric motor according to claim 1, characterized in that the total number of grooves in the armature core consisting of the groove between the main magnetic pole and the auxiliary magnetic pole and the auxiliary groove is the number of magnetic poles of the permanent magnet. 2. The electric motor according to claim 1, wherein the electric motor is different from an integral multiple of P.