JPH02276440A - Motor - Google Patents

Abstract

PURPOSE:To reduce the cogging torque by equipping an armature core with short teeth and long teeth and making the ratio of the effective pitch of any of the short teeth to that of any of the long teeth equal to an appropriate value. CONSTITUTION:3P number of teeth are formed between the winding grooves (a)-(l) of an armature core 4, with L number of long teeth having larger effective pitches than D (=120 deg./P) and M number of short teeth having smaller effective pitches than D, L+M equalling 3P, and L>=3 and M>=3, wherein P is 2 or a larger even number and L and M are integers. The number of short- tooth blocks and that of long-tooth blocks are regulated to integral multiples of three, the sum of the number of the teeth of one of the short-tooth blocks and that of the teeth of the adjacent long-tooth block thereto is made unequal to integral multiples of three, and the ratio of the effective pitch of any of the short teeth to that of any of the long teeth is made approx. G:H, wherein G and H are integers and G<H.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electric motor having a field portion having field magnetic poles and an armature core having a winding groove.

Conventional configuration and its problems In a motor in which winding grooves are provided in the armature core to house multiphase windings, the magnetic flux of the field part is transferred to the teeth formed between the winding grooves. It has the advantage that the output is large because it can converge.

Therefore, it is widely used as a driving power source for industrial robots and NCR machines. However, in such a motor, cogging torque is generated due to the interaction between the magnetic poles of the field section and the winding grooves of the armature core. This will be explained below with reference to the drawings, taking a brushless DC motor as an example.

FIG. 1 is a diagram showing the main parts of the structure of a conventional electric motor.A ring-shaped magnet 3 is attached to the outer periphery of a ferromagnetic rotor 2 attached to a zero-rotation axis I. FIG. The magnet 3 has 411 magnetic poles magnetized at equal angular intervals, forming a field portion. An armature core 4 is arranged at a predetermined gap from the magnet 3 of the field section. Either the magnet 3 or the armature core 4 is rotatably supported relative to the other (in this example, the armature core 4
(The magnet 3 is made to rotate relative to the
, the armature core 4 has 12 winding grooves 5 at equal angular intervals.
Twelve teeth 6 are formed between each winding groove, and three-phase windings A1 to A4 . Bl-B4. C1~
C4 is wrapped.

Winding AI, A2. A3. A4 is wound so as to surround the three teeth, and one ends of the windings A2 and A4 are respectively stored in both winding grooves in which the winding A1 is stored.

Similarly, one end of the S wire Al and A3 is stored in both winding grooves in which the winding A2 is stored, and one end of the S wire Al and A3 is stored in both the winding grooves in which the winding A3 is stored, respectively. and A4 are accommodated, and both winding grooves in which the winding A4 is accommodated accommodate one ends of the windings At and A3, respectively.

Q of other phases, lines B 1 to B4. The same applies to Cl-C4. Hereinafter, A1-A4 will be collectively referred to as the A-phase winding group, 81-B4 will be referred to as the B-phase winding group, and C1-C4 will be referred to as the C-phase winding group.
Let it be a phase winding group. The magnetic flux generated by the magnet 3 in the field section flows into or out of each tooth of the armature core 4, resulting in A, B, 'C
It is linked to the phase winding group. A, B.

There is an electrical phase difference of 120 degrees between the C-phase winding groups. Here, 180 degrees of electrical angle corresponds to 1 magnetic pole pitch of 360 degrees/P (P is the number of magnetic poles of field section) (in this example, since P=4, 90 degrees of mechanical angle is 1 It is a magnetic pitch and corresponds to 180 electrical degrees).

Figure 2 shows the configuration diagram of the drive circuit, and the windings A1 to A1 in Figure 1 are shown in Figure 2.
A4 are connected in series in consideration of each winding direction to form an A-phase winding group. Similarly, windings 81 to B4 are connected in series considering each winding direction to form a B phase winding group, and windings C1 to C4 are connected in series considering each winding direction to form a C phase winding group. It forms a group of windings. The 3-phase winding group is star-connected, and the 0 position detection unit 12 whose terminal is connected to the drive unit 11 detects the rotational position of the magnet 3 and detects the 3-phase winding that changes with the rotation of the magnet 3. sinusoidal signal P
L, P2. Output P3. The drive unit 11 receives a command signal F and three-phase signals Pi, P2 . P3 is input, and a three-phase sinusoidal current proportional to the product of both +
1. , I2. Outputs +3. As a result, current 11. +2. The interaction between I3 and the magnetic flux of magnet 3 generates a rotational force in a predetermined direction.

Next, the cogging torque of this conventional example will be explained with reference to FIG. FIG. 3 is a plan view of the magnet 3 and armature core 4 in FIG. ), cogging torque is generated when the magnetic energy stored in the magnetic field between the field part and the armature core changes in accordance with the relative rotation of the two. In particular, it occurs in relation to both the magnetic poles of the field part and the grooves of the armature core.
When both the magnet 3 of the field part and the armature core 4 have magnetic periodicity as shown in FIG. 1, a cogging torque of a component (matching component) that exists in common in both occurs. Figure 4 shows the distribution characteristics of the magnetic flux density generated by the magnet 3 over the entire circumference (360 degrees).Since magnetic energy is an amount related to the square of the magnetic flux density, a field with the characteristics as shown in Figure 4 is shown. The fundamental harmonic component of the magnetic period/waveform of the magnet 3 in the section is the fourth harmonic component.

Here, a sine wave component generated once per rotation is defined as a first harmonic component. That is, the magnet 3 includes harmonic components such as the 8th, 12th, etc. based on the 4th ignition component.

On the other hand, magnetic non-uniformity (N related to permeance) of the armature core 4 is caused by the winding groove a-1. Winding grooves a-2 of armature core 4 are spaced at equal angular intervals (30 degree intervals)
Therefore, the fundamental harmonic component of the magnetic non-uniformity of the armature core 4 is the 12th blow component. Therefore, based on this, harmonic components such as the 24th, 36th, etc. are included. Cogging torque occurs when the magnetic non-uniformity component of the armature core 4 and the harmonic component of the period and waveform of the magnet 3 match (-defeat), so the cogging torque of this conventional example is 12th order,
Harmonic components such as the 24th order, etc. are generated.

The twelfth winding component of the cogging torque is directly related to the fundamental component of the magnetic inhomogeneity of the armature core 4 caused by the twelve winding grooves. Generally, the fundamental component of the armature core 4 is considerably larger than other harmonic components, and as a result, a very large cogging torque was generated in this conventional electric motor.

The present applicant has proposed a method for reducing such cogging torque in Japanese Patent Application No. 53-145489. In Japanese Patent Application No. 53-145489, cogging torque is reduced by increasing the basic harmonic component of cogging torque by providing auxiliary grooves on each tooth of the armature core. However, in order to sufficiently reduce the cogging torque by such a method, the basic order of the cogging torque needs to be significantly higher, and many auxiliary grooves must be provided in the armature core. It is not practical, and even if many auxiliary grooves are provided, the basic component of cogging torque is 'Fi1
The cogging torque could not be sufficiently reduced because it matched the basic components of the machine core.

Purpose of the Invention The present invention takes these points into consideration and provides an electric motor having a field portion having field magnetic poles and an armature core having a winding groove, the motor having extremely low cogging torque. It is something to do.

Structure of the Invention In the present invention, a permanent magnet material is used to form a P pole (
It is equipped with a field part having field magnetic poles (P is an even number of 2 or more) at equal angular intervals on the circumference, and an armature core in which 3-phase windings are housed in 32 winding grooves. , an electric motor in which either one of the field part and the armature core is rotatable relative to the other, and the armature core has 3P teeth formed between the winding grooves. and the effective pinch is D=12
L long teeth larger than 0°/P (L is an integer) and M teeth with an effective pitch smaller than D (M is an integer)
, the number of the long teeth and the short teeth is L0M=3P L ≧ 3 M ≧ 3, and a short tooth block consisting of two or more adjacent short teeth and at least one short tooth. Each has a plurality of long tooth blocks made of the long teeth, the short tooth blocks and the long tooth blocks are arranged alternately on the circumference, and the number of the short tooth blocks and the number of the long tooth blocks are each 3. and the sum of the number of teeth of the short tooth block and the number of teeth of the long tooth block of the adjacent set is different from an integral multiple of 3, and
The ratio of the effective pitch of any of the short teeth to the effective pitch of any of the long teeth is G! H (however, 0.11 is an integer and G <
11), the above objective was achieved.

Further, in the present invention, a permanent magnet material is used to form a field part having P poles (P is an even number of 2 or more) at equal angular intervals on the circumference, and a field part having 3P windings. An electric motor comprising an armature core storing three-phase windings in a wire groove, and one of the field part and the armature core is rotatable relative to the other, The armature core has 3P teeth formed between the winding grooves, and L teeth having an effective pitch larger than D÷120@/P (L is an integer).
long teeth, and M teeth whose effective pitch is smaller than D (however, M
is an integer), the number of the long teeth and the short teeth is L + M = T L ≧ 3 M ≧ 3, and the short tooth block consisting of at least one short tooth and two or more adjacent There is a plurality of long tooth blocks each consisting of the long teeth, and the short tooth blocks and the long tooth blocks are arranged alternately on the circumference, and the number of the short tooth blocks and the number of the long tooth blocks are set respectively. the sum of the number of teeth of the short tooth block and the number of teeth of the long tooth block of the adjacent set is different from an integral multiple of 3, and
The above objective is achieved by setting the ratio of the effective pitch of any of the short teeth to the effective pitch of any of the long teeth to approximately G:H (where G and H are integers and G<H). be.

Furthermore, the present invention provides a rotor that forms a field portion having P-pole (P is an even number of 2 or more) permanent magnet magnetic poles at approximately equal angular intervals on the circumference, and a rotor having a predetermined gap between the permanent magnet magnetic poles and the rotor. an armature core that is provided with three-phase windings in 3P winding grooves, and a drive circuit that supplies three-phase currents to the three-phase windings as the rotor rotates. The armature core has 3P teeth formed between the winding grooves, and L teeth having an effective pitch greater than D-120°/P.
However, it has long teeth (L is an integer) and M short teeth (however, M is an integer) whose effective pitch is smaller than D, and the number of the long teeth and the short teeth is L+M=3P L ≧ 3 M ≧ 3, each of a plurality of short tooth blocks consisting of two or more adjacent short teeth and a plurality of long tooth blocks consisting of at least one long tooth, and the short tooth block and the long tooth block are arranged in a circle. They are arranged alternately on the circumference, and the number of the short tooth blocks and the number of the long tooth blocks are each an integral multiple of 3, and the number of teeth of the short tooth blocks and the number of teeth of the long tooth blocks of one adjacent set are equal to each other. The sum is different from an integer multiple of 3, and
The ratio of the effective pitch of any short tooth to the effective pitch of any long tooth is G: H (where G and H are integers and G<H
), the above objective was achieved.

Furthermore, the present invention provides a rotor that forms a field portion having P-pole (P is an even number of 2 or more) permanent magnet magnetic poles at approximately equal angular intervals on the circumference, and a rotor having a predetermined gap between the permanent magnet magnetic poles and the rotor. an armature core that is provided with three-phase windings in 3P winding grooves, and a drive circuit that supplies three-phase currents to the three-phase windings as the rotor rotates. The armature core has 3P teeth formed between the winding grooves, and L teeth (with an effective pitch greater than D=120'/P).
However, it has long teeth (L is an integer) and M short teeth (however, M is an integer) whose effective pitch is smaller than D, and the number of the long teeth and the short teeth is L+M-T L ≧ 3 M ≧ 3, and each has a plurality of short tooth blocks consisting of at least one short tooth and a plurality of long tooth blocks consisting of two or more adjacent long teeth, and the short tooth block and the long tooth block are arranged in a circle. Arranged alternately on the circumference, the number of the short tooth blocks and the number of the long tooth blocks are each an integral multiple of 3, and the sum of the number of teeth of the short tooth blocks and the number of teeth of the long tooth blocks of adjacent 1 & Il. be different from an integer multiple of 3, and the ratio of the effective pitch of any of the short teeth to the effective pitch of any of the long teeth is G:H (however, G and H are integers and G<H
), the above objective was achieved.

DESCRIPTION OF EMBODIMENTS FIG. 5 shows a plan development view of essential parts representing an embodiment of the present invention. In FIG. 5, a magnet 3 attached to a rotor 2 has four magnetic poles spaced at equal angular intervals; Armature core 4
It faces the 12 winding grooves azl and 12 teeth with a predetermined gap.

The 12 winding grooves of the armature core 4 are marked with A and B in Fig. 1.
, the three-phase winding group is wound in a die-wound manner similar to the C-phase winding group (not shown). That is, the winding A1 is wound in the winding grooves a to d, the winding A2 is wound in the winding grooves d to g, and the winding A2 is wound in the winding grooves g to j. A3 is wound, and the winding A is passed from the winding groove j to a.
4 is wrapped and rolled! IIAA1 to A4 are connected in series in consideration of the winding direction to form an A-phase winding group.

Similarly, the winding B1 is wound from the winding groove C to f, the winding B2 is wound from the winding groove i to the winding groove i, and the winding B2 is wound from the winding groove i to 2. The winding B3 is wound in the winding groove 2.
A winding B4 is wound from B1 to C, and the windings B1 to B4 are connected in series in consideration of the winding direction to form a third phase winding group. Furthermore, the winding C1 is wound from the winding groove e to h, and the winding C1 is wound from the winding groove to k.
2 is wound, a winding C3 is wound across the winding groove k to b, and the winding groove e! : The drive circuit of this embodiment, in which the winding C4 is wound across, and the windings C1 to C4 are connected in series in consideration of the winding direction to form a C-phase winding group. is the same as the configuration shown in FIG. 2, and its explanation will be omitted.

In the embodiment shown in FIG. 5, the winding groove a of the armature core 4 is
-1 are arranged at unequal angular intervals, and the effective pitch of the teeth formed between the winding grooves is made non-uniform. Here, the effective pitch of the tooth is the angle formed by the center of the winding grooves at both ends of the tooth, and the number of winding grooves is T-3・P-12 (P is the number of magnetic poles in the field part) P-4), the effective pitch of each tooth when arranged at equal angular intervals is D=360"/T (in this example, D-120'/P-30'). Note that the teeth larger than D are lengthened. teeth, and teeth smaller than D are called short teeth.Teeth a-b (teeth are represented by winding grooves at both ends) are short teeth, teeth 6-c are short teeth, and teeth c-d are short teeth. Short teeth, teeth d-e are long teeth, teeth e-f are short teeth, teeth f-g are short teeth, teeth g
-h is a short tooth, tooth h-1 is a long tooth, tooth i-j is a short tooth, tooth j-
is a short tooth, tooth -N is a short tooth, and tooth ε-a is a long tooth. In other words, the number of long teeth is L-3 and the number of short teeth is M=9.0 between winding grooves a and d (a, b, c, d) and between winding grooves e and h. (e, f, g, h) and winding grooves i to l
Between ct, j, and ff1), only the short teeth are partially concentrated, forming a short tooth block consisting of three short teeth (no long teeth included). Between the wire grooves d and e (d, e), between the winding grooves i and i (h, i), and between the winding grooves i and a (ffi, a), only the long teeth are partially The long tooth block is concentrated in the teeth and forms a long tooth block consisting of one long tooth (not including short teeth), that is, three sets of short tooth blocks and long tooth blocks are arranged alternately on the circumference. ing. Short teeth a-b, b-c, c-d, e-
f, f-g, g-h.

The effective pitch of i−j+j − and −1 is 360”/
(T+3)=24° or approximately equal. Long tooth de, h-i, I! , -a is equal to or approximately equal to 720'/(T+3)=48'. In other words, the ratio of the effective pitch of the short teeth to the effective pitch of the long teeth is R; R+1 (R=1
), each long tooth is provided with one auxiliary groove, and the entire armature core groove consisting of the winding groove and the auxiliary groove is spaced at equal angular intervals (360°/15-24＠ The centers of the valley grooves (the centers seen from the magnetic effect) are arranged at substantially equal angular intervals.

Next, the cogging torque of this embodiment will be explained. As already explained, cogging torque occurs when the harmonic components of the magnetic inhomogeneity caused by the winding grooves in the armature core match the harmonic components of the magnetic period and waveform caused by the magnetic poles of the field section. . The magnetic period/waveform of the magnet 3 in the field section is a periodic function whose period is 1M1 pole pitch 360°/P of the magnet 3. Therefore, 1 of magnet 3
The magnetic non-uniformity of the armature core 4 (magnetic fluctuations caused by the arrangement of the winding grooves and auxiliary grooves) can be considered with the magnetic scratch pitch as the basic period. Cogging torque becomes smaller. magnet 3
FIG. 6 shows the phase relationship between the winding groove a-1 and the auxiliary grooves a' to C' of the armature core 4, with one magnetic pole pitch as the basic period.

Winding grooves a, d, and g accommodate the A-phase winding group.

j is provided with a phase shift with a phase difference of 1/(T+3)-1/15 of l magnetic pole pitch (winding grooves a, d).

The phases of g and j differ in 4 or more places), and their fluctuation range is 3/15 of 1 magnetic pole pitch = 115 (1 of 1 magnetic pole pitch)
Similarly, the winding grooves c, f, and i accommodate the B-phase winding group.

A phase shift is provided for l with a phase difference of 1/15 of one magnetic pole pitch, and the variation range is set to 115 of l magnetic pole pitch. Furthermore, a winding groove in which a C-phase winding group is housed;
e, h, k are provided with a phase shift of l/15 phase difference of 1M1 pole pitch, and the variation range is 0 person phase winding groove group (a,
d, g, j) and B phase winding groove group (c,
r, t, l) and C phase winding groove group (b, e
, h, k) of 1 magnetic pole pitch.
There is a phase difference of /3. Further, the auxiliary grooves a' to C' are located in a phase different from the phase of the winding grooves a to r, and the winding grooves az
The entire groove consisting of the auxiliary grooves a' to C' has a phase difference of 1/15. Figure 7 shows the winding groove a.
-l and auxiliary grooves a' to C' showing the waveform of the magnetic fluctuation of the armature core 4.0 The magnetic fluctuation due to each winding groove changes gently depending on the opening width of the winding groove. do.

Since the winding groove a-1 and the auxiliary grooves a' to C' have a phase difference of 1/15, the composite magnetic fluctuation (AC bone) is considerably small. FIG. 8 shows the zero winding grooves a, d, and the magnetic fluctuations of the conventional motor shown in FIG.
g and j have the same phase, winding grooves c, r, t, and z have the same phase, and winding grooves e and h have the same phase, so the conventional electric motor shown in Fig. 1 The composite magnetic fluctuation is very large (the conventional example in Fig. 1 does not have auxiliary grooves a' to C').
.

Comparing Figures 7 and 8, it can be seen that the magnetic fluctuations of the motor in this example are significantly smaller.As a result, the cogging torque in this example is significantly reduced. .

Furthermore, each winding AI, A2 . A3゜A4. B
l, B2. B3. B4. The effective pitch of CI, C2, C3°C4 is from (16/15 of 1m pole pitch) = 192 degrees (electrical angle) or less to (415 of 1m pole pitch) = 144 degrees (
electric angle) or more. Here, the effective pitch of the winding is the angle formed between the centers of the winding grooves in which the winding is housed. Looking at the A-phase winding group, the angle between the A1 winding grooves a and d is 144° (3 short dentary bones)
, A2 winding groove d - gr! The angle of is 1
92° (one long tooth and two short teeth), the angle between A3's winding groove g-J is 192＠ (one long tooth and two short teeth)
(2 short dentary bones), the angle between the winding groove j-a of A4 is 192° (1 long tooth and 2 short dentary bones), B
Looking at the winding group of the phase, the angle between the winding groove c-4 of B1 is 192° (one long tooth and two short teeth), and the angle between the winding groove c-4 of B1 is 192° (one long tooth and two short teeth) The angle between the wire groove fi is r92
° (1 long tooth and 2 short teeth), the angle between the winding groove l-1 of B3 is 144° (3 short teeth), B
The angle between the winding groove l-0 of No. 4 is 192@(1
Looking at the C-phase winding group, which has three long teeth and two short teeth, the angle between the winding grooves e and h in which CI is wound is 144° (three short teeth bone), the angle between the wound winding groove h- of C2 is 192° (one long tooth and two short teeth), and the angle between the wound winding groove h- of C3 is -b The angle between is 192
° (1 long tooth and 2 short dentary bones), the angle between the winding groove be and e of C4 is 192° (1 long tooth and 2 short dentary bones). In this way, the variation range of the winding groove in which the windings of each phase are housed is reduced (1/1 of the pitch of one magnetic pole).
3 or less), and if the variation range of the effective pitch of the winding is made small (from 192 degrees or less to 144 degrees or more), the winding work becomes easier and automation becomes possible.

In the embodiment shown in FIG. 5 described above, an auxiliary groove was provided at the tip of the long tooth, but the auxiliary groove is not necessarily necessary.
Even if + b ' * c ' is eliminated, the resultant magnetic fluctuation is smaller than the conventional example shown in Figure 8. In general, by devising the arrangement of long teeth and short teeth, a short tooth block with an integral multiple of 3 is created. Cogging torque can be reduced by alternately arranging long tooth blocks. At this time, if the total number of teeth in the short tooth block and long tooth block of adjacent tm is made different from a multiple of 3, the phase of the teeth can be easily varied.

Also, the total effective pitch of the consecutive 3g short tooth block and long tooth block is set equal to (360°/P) ・Q, and the total number of teeth of the adjacent 1 & Il short tooth block and long tooth block is set to Q. If they are made equal, the phase difference between the three-phase winding groups can be made equal to 120 degrees (electrical angle), and the three-phase windings can be equally arranged.

Also, if an auxiliary groove is provided on at least one long tooth,
The cogging torque reduction effect can be increased. Furthermore, by setting the effective pitch of the short teeth and the effective pitch of the long teeth to R:R+1 or R:R+3 (R is an integer), the entire armature core groove consisting of the winding groove and the auxiliary groove is set to the effective pitch of the short teeth. If they are arranged at intervals of 1/R of the pitch, the cogging torque can be easily reduced. Other examples of such configurations are shown in Table 1.

Table 1 The configuration of Table 1 (A) is based on the effective pitch of the short teeth shown in Figure 5 by 2 units of angle (l unit angle is 360"/27 = 13.33°)
The effective pitch of the long teeth is set to 3 unit angles, auxiliary grooves are provided on the short teeth and long teeth, and the entire groove consisting of the winding groove and the auxiliary groove is arranged at 1 unit angle intervals.Table 0 In the configuration of 1(B), the effective pitch of the short teeth in Fig. 5 is set to 3 unit angles (1 unit angle is 60°/39-9.23°), and the effective pitch of the long teeth is set to 4 unit angles. , auxiliary grooves are provided on the short teeth and long teeth, and the entire groove consisting of the winding groove and the auxiliary groove is arranged at 1 unit angular intervals. The effective pitch of the teeth is 1 unit angle (l unit angle is 360
'/21-17.14°), and the effective pitch of the long teeth is 4.
Auxiliary grooves are provided on the long teeth in unit angle, and the entire grooves consisting of the SwA groove and the auxiliary groove are arranged at intervals of one unit angle.

Furthermore, even when the long tooth block consists of three long teeth and the short tooth block consists of one short tooth, cogging torque can be reduced. Such a configuration is shown in Table 2.

(Margin below) Table 2 The configuration in Table 2 (A) consists of three sets of long tooth blocks consisting of three long teeth and three short tooth blocks consisting of one short tooth arranged alternately on the circumference. (Exchange the number of short teeth and long teeth in Figure 5), set the short tooth Φ effective pitch by 1 unit angle (1 angle! ;! 360
” /21 = 17.14”), set the effective pitch of the long teeth to 2 unit angles, provide auxiliary grooves on the long teeth, and make the entire groove consisting of the winding groove and the auxiliary grooves at 1 unit angle intervals. This is what was placed. In the configuration shown in Table 2 (B), the effective pitch of the short teeth is 2 unit angles (1 unit angle is 360@/33=10
．． 91"), the effective pitch of the long teeth is 3 unit angles, auxiliary grooves are provided on the long teeth and short teeth, and the entire groove consisting of the winding groove and auxiliary groove is arranged at 1 unit angle intervals. In a certain configuration shown in Table 2 (C), the effective pitch of the short teeth is set by 3 unit angles (
l unit angle is 360"/33-10.91°), the effective pitch of the long teeth is set to 4 unit angles, auxiliary grooves are provided on the long teeth and short teeth, and the entire groove consisting of the winding groove and the auxiliary groove is are arranged at 1 unit angle intervals.

Moreover, even when the long tooth block consists of two long teeth and the short tooth block consists of two short teeth, cogging torque can be reduced. Such a configuration is shown in Table 3.

Table 3 The configuration of Table 3 (A) shows that the effective pinch of the two short teeth is all 1 unit angle (1 unit angle is 360°/21 = 17.14
°), the effective pitches of the two long teeth are set to 2 and 3 unit angles, respectively, auxiliary grooves are provided on the long teeth, and the entire groove consisting of the winding groove and the auxiliary groove is arranged at 1 unit angle intervals. In the configuration shown in Table 3 (B), the effective pitch of the two short teeth is all 3 unit angles (1 unit angle is 360°/45-
8°), the effective pitch of the two long teeth is 4 units angle and 5 unit angle, respectively, auxiliary grooves are provided on the long teeth and short teeth, and the entire groove consisting of the winding groove and the auxiliary groove is 1 unit angle. They are arranged at angular intervals.

In each of the above embodiments, the number of magnetic poles of the magnet 3 in the field section is set to P-4, but the present invention is not limited to such a case.For example, the number of magnetic poles of the magnet 3 in the field section is If P-8 is used, three-phase windings will be wound in T-3P-24 winding grooves, but a short tooth block consisting of seven short teeth and one short tooth block will be wound. Table 4 shows an example in which cogging torque is reduced by arranging three sets of long tooth blocks alternately on the circumference.

(Margin below) The configuration of Table 4 (A) has the effective pitch of the short teeth set by 1 unit angle (
One unit angle is 360@/27-13.33°), the effective pitch of the long teeth is set to 2 unit angles, and an auxiliary groove is provided on the long teeth, so that the entire groove consisting of the winding groove and the auxiliary groove is They are arranged at 1 unit angle intervals.

The configuration in Table 4 (B) has an effective pitch of short teeth of 2 units angle (
1 unit angle is 360@/65=5. '538°),
The effective pitch of the long teeth is set to 3 unit angles, and auxiliary grooves are provided on the long teeth and short teeth, so that the entire groove consisting of the winding groove and the auxiliary groove is 1.
The configuration in Table 4 (C), which is arranged at unit angle intervals, has an effective pitch of short teeth of 3 unit angles (1 unit angle is 36
0j/75-4.8°), set the effective pitch of the long teeth to 4 units of angle, provide auxiliary grooves on the long teeth and short teeth, and make the entire groove consisting of the winding groove and auxiliary groove 1 unit. They are arranged at angular intervals.

In addition, when the number of magnetic poles of the magnet 3 in the field part is set to P=8, three sets of short tooth blocks consisting of one short tooth and long tooth blocks consisting of seven long teeth are arranged alternately on the circumference. Table 5 shows an example in which the cogging torque is reduced by the arrangement.

The configuration in Table 5(A) has the effective pitch of the short teeth set by 1 unit angle (
One unit angle is 360"/45 = 8 degrees), the effective pitch of the long teeth is set to 2 unit angles, and an auxiliary groove is provided on the long teeth, so that the entire groove consisting of the winding groove and the auxiliary groove is one unit. The configuration shown in Table 5 (B), which is arranged at angular intervals, has an effective pitch of short teeth of 2 units of angle (1 unit of angle is 360' / 69 = 5
．． 217"), the effective pitch of the long teeth is 3 unit angles, auxiliary grooves are provided on the long teeth and short teeth, and the entire groove consisting of the winding groove and auxiliary groove is arranged at 1 unit angle intervals. The configuration of Table 5 (C) is as follows: The effective pitch of the short teeth is set to 3 unit angles (1 unit angle is 360°/93 = 3.871"), and the effective pinch of the long teeth is set to 4 unit angles. Auxiliary grooves are provided on the long teeth and short teeth, and the entire grooves consisting of the winding groove and the auxiliary groove are arranged at one unit angle interval.

Although various embodiments have been described, the present invention is not limited to such embodiments.

For example, by combining the embodiment with P=4 and the embodiment with P-8, it is possible to configure a motor in which the number of magnetic poles in the field section is P=12. In addition, by simply doubling the configuration of the embodiment shown in FIG.
It is possible to construct a motor with twice the number of magnetic poles and twice the number of winding grooves.

Using a permanent magnet material, there is a field part having P-pole field magnetic poles at equiangular intervals (equal angular intervals or approximately equiangular intervals) on the circumference, and a 3-phase magnet in T winding grooves. In the case of a motor equipped with an armature core containing windings of D-360”/
It has L long teeth larger than T (L is an integer) and M short teeth whose effective pitch is smaller than D (M is an integer), and the number of long teeth and short teeth is L ≧ 3. M ≧ 3, and has the same number of short tooth blocks consisting of two or more short teeth and long tooth blocks consisting of at least one long tooth, and the short tooth blocks and long tooth blocks are arranged alternately on the circumference. In addition, the cogging torque can be easily reduced by increasing the number of short tooth blocks and long tooth blocks by an integral multiple of three.

In addition, a permanent magnet material is used to form a field part having P-pole field magnetic poles at equiangular intervals (equal angular intervals or approximately equiangular intervals) on the circumference, and T winding grooves. In the case of a motor in which a port is installed on the armature core containing three-phase windings, and one of the field part and the armature core is rotatable relative to the other, the armature core is Pitch is D=360
L long teeth larger than °/T (L is an integer),
A short tooth block having M short teeth with an effective pitch smaller than D (M is an integer), the number of long teeth and short teeth being L ≧ 3 M ≧ 3, and consisting of at least one short tooth. and the same number of long tooth blocks consisting of two or more long teeth, short tooth blocks and long tooth blocks are arranged alternately on the circumference, and the number of short tooth blocks and long tooth blocks is 3 each. Cogging torque can be easily reduced by multiplying by an integer.

In addition, if the sum of the number of teeth in the short tooth block and the number of teeth in the long tooth block of the adjacent 1 & [l is made different from a multiple of 3, the phase of the winding groove can be easily varied, and the cogging torque It is effective in reducing Furthermore, the effective pitch of three consecutive short tooth blocks and long tooth blocks is (360°/P
) ・When Q is equal to (Q is an integer greater than or equal to 2), if the sum of the number of teeth in an adjacent set of short tooth blocks and the number of teeth in long tooth blocks is equal to Q, then a three-phase winding While maintaining the phase between the groups at 120 degrees (electrical angle), the phase of the winding groove can be easily varied, which is effective in reducing cogging torque.

Furthermore, the ratio of the effective pitch of the short teeth to the effective pitch of the long teeth is R
:R+1 (where R is an integer) or at least 1
If an auxiliary groove is provided on each of the long teeth, and the entire groove consisting of the winding groove and the auxiliary groove is arranged at an interval of 1/R of the effective pitch of the short teeth, the cogging torque can be significantly reduced. can(
However, the total number of grooves is not an integral multiple of the number of magnetic poles P).

In the above embodiments, the magnet is placed on the inside and the armature core is placed on the outside, but the relationship may be reversed.

Further, the field section is not limited to an annular magnet, but may be formed of a plurality of m-pole pieces of magnets, and various other modifications can be made without changing the gist of the present invention.

Effects of the Invention The present invention provides an armature core with short teeth and long teeth and arranges them in a special relationship, thereby realizing an electric motor with extremely low cogging torque. Therefore, based on the present invention, it is possible to use, for example, an electric motor for driving between robots,
If it is configured as a drive motor for C equipment, highly accurate rotational drive and position control will be possible.

[Brief explanation of drawings]

Figure 1 is a structural diagram of the main parts of a conventional electric motor, Figure 2 is a configuration diagram of its drive circuit, Figure 3 is a plan development view of the electric motor in Figure 1,
Fig. 4 is a diagram showing the distribution of magnetic flux density of the magnet in the field part, Fig. 5 is a plan development view of a motor according to an embodiment of the present invention, and Fig. 6 is a diagram showing the distribution of the magnetic flux density of the magnet in the field part. A diagram showing the phase relationship of the winding grooves when looking at the armature core shown in the figure, Figure 7 is a diagram showing the magnetic fluctuation of the embodiment shown in Figure 5, and Figure 8 is a diagram showing the magnetic variation shown in Figure 1. FIG. 3 is a diagram showing magnetic fluctuations in a conventional example. 2...Rotor, 3...Magnet, 4
・・・・・・Armature core, 5. a-1... Winding groove, 6... Teeth, a'~CI, ,, ,...
Auxiliary groove, At-A4. Bl~B4. C1~C4...
...winding wire. Name of agent: Patent attorney Shigetaka Awano (1 person) Figure 1 Y' Fossa Figure Tomi Figure

Claims (12)

[Claims] (1) Using permanent magnetic material, P pole (however, P is 2
The field part includes a field part having field magnetic poles (the above even number) at equal angular intervals on the circumference, and an armature core in which 3 phase windings are housed in 3P winding grooves. A motor in which either one of the magnetic part and the armature core is rotatable relative to the other, the armature core having 3P teeth formed between the winding grooves, Effective pitch is D=120°
/L long teeth larger than P (however, L is an integer) and M short teeth whose effective pitch is smaller than D (however, M is an integer), and the number of the long teeth and the short teeth is L+M=3P L≧3 M≧3, each having a plurality of short tooth blocks each consisting of two or more adjacent short teeth and a plurality of long tooth blocks consisting of at least one long tooth; and the long tooth blocks are arranged alternately on the circumference, the number of the short tooth blocks and the number of the long tooth blocks are each an integral multiple of 3, and the number of teeth of an adjacent set of the short tooth blocks and the number of the long tooth blocks are The sum of the number of teeth of the long tooth block is different from an integral multiple of 3, and
An electric motor in which the ratio of the effective pitch of any of the short teeth to the effective pitch of any of the long teeth is approximately G:H (where G and H are integers and G<H). (2) The electric motor according to claim (1), characterized in that G:H=R:R+1 (where R is an integer). (3) The electric motor according to claim (2), characterized in that R=1. (4) Using permanent magnetic material, P pole (however, P is 2
The field part includes a field part having field magnetic poles (the above even number) at equal angular intervals on the circumference, and an armature core in which 3 phase windings are housed in 3P winding grooves. A motor in which either one of the magnetic part and the armature core is rotatable relative to the other, the armature core having 3P teeth formed between the winding grooves, Effective pitch is D=120°
/L long teeth larger than P (however, L is an integer) and M short teeth whose effective pitch is smaller than D (however, M is an integer), and the number of the long teeth and the short teeth is L+M=T L≧3 M≧3, each having a plurality of short tooth blocks consisting of at least one short tooth and a plurality of long tooth blocks consisting of two or more adjacent long teeth, and the short tooth block and the long tooth blocks are arranged alternately on the circumference, the number of the short tooth blocks and the number of the long tooth blocks are each an integral multiple of 3, and the number of teeth of an adjacent set of the short tooth blocks and the number of the long tooth blocks are The sum of the number of teeth of the long tooth block is different from an integral multiple of 3, and
An electric motor in which the ratio of the effective pitch of any of the short teeth to the effective pitch of any of the long teeth is approximately G:H (where G and H are integers and G<H). (5) The electric motor according to claim (4), characterized in that G:H=R:R+1 (where R is an integer). (6) The electric motor according to claim (5), characterized in that R=1. (7) A rotor forming a field portion having P-pole (P is an even number of 2 or more) permanent magnet magnetic poles at approximately equal angular intervals on the circumference, and a rotor that is provided with a predetermined gap from the permanent magnet magnetic poles. , an armature core that stores three-phase windings in 3P winding grooves, and a drive circuit that supplies three-phase currents to the three-phase windings as the rotor rotates, The armature core has 3P teeth formed between the winding grooves, L long teeth with an effective pitch larger than D=120°/P (L is an integer), and 3P teeth with an effective pitch larger than D=120°/P. It has M short teeth smaller than D (M is an integer), the number of the long teeth and the short teeth is L+M=3P L≧3 M≧3, and two or more adjacent short teeth and a plurality of long tooth blocks each consisting of at least one of the long teeth, the short tooth blocks and the long tooth blocks are arranged alternately on the circumference, and the number of the short tooth blocks is and the number of the long tooth blocks are each an integral multiple of 3, and the sum of the number of teeth of the adjacent short tooth block and the number of teeth of the long tooth block is different from an integral multiple of 3, and
An electric motor in which the ratio of the effective pitch of any of the short teeth to the effective pitch of any of the long teeth is approximately G:H (where G and H are integers and G<H). (8) The electric motor according to claim (7), characterized in that G:H=R:R+1 (where R is an integer). (9) The electric motor according to claim (8), characterized in that R=1. (10) A rotor that forms a field part having P-pole (P is an even number of 2 or more) permanent magnet magnetic poles at approximately equal angular intervals on the circumference, and a rotor that is provided with a predetermined gap from the permanent magnet magnetic poles. , an armature core that stores three-phase windings in 3P winding grooves, and a drive circuit that supplies three-phase currents to the three-phase windings as the rotor rotates, The armature core has 3P teeth formed between the winding grooves, L long teeth with an effective pitch larger than D=120°/P (L is an integer), and 3P teeth with an effective pitch larger than D=120°/P. It has M short teeth smaller than D (M is an integer), the number of the long teeth and the short teeth is L+M=T L≧3 M≧3, and consists of at least one short tooth. A plurality of short tooth blocks and a plurality of long tooth blocks each consisting of two or more adjacent long teeth are provided, the short tooth blocks and the long tooth blocks are arranged alternately on a circumference, and the number of the short tooth blocks is and the number of the long tooth blocks are each an integral multiple of 3, and the sum of the number of teeth of the adjacent short tooth block and the number of teeth of the long tooth block is different from an integral multiple of 3, and
An electric motor in which the ratio of the effective pitch of any of the short teeth to the effective pitch of any of the long teeth is approximately G:H (where G and H are integers and G<H). (11) The electric motor according to claim (11), characterized in that G:H=R:R+1 (where R is an integer). (12) The electric motor according to claim (11), characterized in that R=1.