JPH02269447A - Motor - Google Patents

Abstract

PURPOSE:To obtain a motor of which the cogging torque is small by a method wherein the sum of the numbers of teeth of one set of a short-tooth block and a long-tooth block adjacent to each other is set to be equal to Q (Q is an integer of 2 or above) when the effective pitch of the whole of three sets of short-tooth blocks and long-tooth blocks being successive is about (360 deg./P).Q. CONSTITUTION:The disposition of long teeth and short teeth is contrived so that short-tooth blocks and long-tooth blocks in the number of integral multiples of three are disposed alternately, and thereby a cogging torque is reduced. If the total sum of the numbers of teeth of one set of the short-tooth block and the long-tooth block adjacent to each other is made different from multiples of three, the phase of the teeth can be changed easily. If the effective pitch of the whole of three sets of the short-tooth blocks and the long-tooth blocks being successive is set to be equal to (360 deg./P).Q and the total sum of the numbers of teeth of one set of the short-tooth block and the long-tooth block adjacent to each other is set to be equal to Q, in addition, a phase difference between winding groups of three phases can be made equal to 120 degrees (electrical angle) and thus a three-phase winding can be disposed uniformly.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electric motor having a field portion having field iut 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 NC equipment. 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 shaft 1. FIG. The magnet 3 has four 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. One of the magnet 3 and the armature core 4 is rotatably supported relative to the other (in this example, the magnet 3 is configured to rotate relative to the armature core 4).

The armature core 4 is provided with 12 winding grooves 5 at equal angular intervals, 12 teeth 6 are formed between each winding groove, and three-phase windings A1 to A4 are formed. ．． Bl~B4. C1-0
0 winding Al, A2 . A3. A4 is 3
One end of the windings A2 and A4 are respectively stored in both winding grooves in which the winding A1 is stored. Similarly, one ends of windings A1 and A3 are stored in both winding grooves in which winding A2 is stored, and one ends of winding A2 and A3 are stored in both winding grooves in which winding A3 is stored, respectively. One end of the winding A4 is stored in both winding grooves in which the winding A4 is stored, and one ends of the windings A1 and A3 are respectively stored in the tail, and the other phase winding MBI-B4. C1~C
The same applies to 4. Hereinafter, A1-A4 will be collectively referred to as the A-phase winding group, B1-B4 will be referred to as the B-phase winding group, and 0
1 to C4 are a C-phase winding group. Magnet 3 in the field part
The generated magnetic flux flows into or out of each tooth of the armature core 4,
It is linked to the A, B, and C phase winding groups. There is an electrical phase difference of 120 degrees between the A, B, and C phase winding groups. Here, 180 degrees of electrical angle is 360 degrees of one magnetic pole pitch of the field part.
It corresponds to °/P (P is the number of magnetic poles in the field part) (in this example,
Since it is P-4, 90 degrees of mechanical angle is one magnetic pole pitch,
(equivalent to 180 electrical degrees).

FIG. 2 shows a configuration diagram of the drive circuit. Figure 1 Volume allA
1 to 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 winding group. 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 signals PI, P2. Output P3. The drive unit 11 receives a command signal F and three-phase signals PI, P2 . P3 is input, and three-phase sinusoidal currents 11, 12, and 13 proportional to the product of both are output. As a result, the interaction between the currents 11, 12, and 13 flowing to the A, B, and C phase winding groups and the magnetic flux of the 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 (an amount related to permeance) of the armature core 4 is caused by the winding grooves a to l. Since the winding grooves a-2 of the Mitsuko iron core 4 are arranged at equal angular intervals (30 degree intervals), the fundamental harmonic component of the magnetic non-uniformity of the armature core 4 is the 12th coil. Becomes an ingredient. Therefore, based on this, harmonic components such as the 24th, 36th, etc. are included. Cogging torque occurs when the component of magnetic non-uniformity present in 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 Harmonic components such as 12th order, 24th order, etc. are generated.

The twelfth 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 using this method, the basic order of the cogging torque must be made considerably high, and many auxiliary grooves must be provided in the armature core, making it impractical. Moreover, even when many auxiliary grooves were provided, the cogging torque could not be sufficiently reduced because the basic component of the cogging torque coincided with the basic component of the armature core.

Purpose of the Invention The present invention takes these points into consideration, and provides an electric motor with extremely low cogging torque, which is equipped with a field part having field magnetic poles and an armature core having winding grooves. 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 in which field magnetic poles (P is an even number of 2 or more) are arranged at equal angular intervals on the circumference, and an armature core in which 3-phase windings are housed in 3P 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 pitch is D=12
L long teeth larger than 0°/P (L is an integer) and M teeth whose effective pitch is 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 a short tooth block consisting of two or more adjacent short teeth and at least one of the long teeth. Each has a plurality of long tooth blocks each consisting of teeth, the short tooth blocks and the long tooth blocks are arranged alternately on the circumference, and three continuous tooth blocks are arranged.
When the overall effective pitch of a pair of the short tooth block and the long tooth block is approximately (360°/P) Q (where Q is an integer of 2 or more), the teeth of the adjacent short tooth block The above object is achieved by making the sum of the number of teeth and the number of teeth of the long tooth block equal to Q, and by providing an auxiliary groove on at least the long teeth.

Further, in the present invention, a permanent magnet material is used to form a field part having P poles (where P is an even number of 2 or more) field iut poles at approximately 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 is
3P teeth are formed between the winding grooves, L long teeth (where L is an integer) with an effective pitch greater than D=120°/P, and M teeth (where L is an integer) with an effective pitch 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 a short tooth block consisting of at least one short tooth and two or more short teeth Each has a plurality of long tooth blocks each consisting of the adjacent long teeth, the short tooth blocks and the long tooth blocks are arranged alternately on the circumference, and three continuous teeth blocks are provided.
The overall effective pitch of the short tooth block and the long tooth block of the pair is (360'/P) ・Q (however, Q is 2
or above), the sum of the number of teeth in the short tooth block and the number of teeth in the long tooth block of adjacent III is made equal to Q, and by providing an auxiliary groove at least on the long teeth, the above-mentioned It has achieved its purpose.

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. 3 consecutive and alternately arranged on the circumference
When the overall effective pitch of a pair of the short tooth block and the long tooth block is approximately (360"/P) Q (where Q is an integer of 2 or more), the teeth of the adjacent short tooth block The above object is achieved by making the sum of the number of teeth and the number of teeth of the long tooth block equal to Q, and by providing an auxiliary groove on at least the long teeth.

The purpose has been 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 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 (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. 3 consecutive and alternately arranged on the circumference
When the overall effective pitch of the short tooth block and the long tooth block of m is about (360"/P) ・Q (where Q is an integer of 2 or more), the teeth of one set of adjacent short tooth blocks The above object is achieved by making the sum of the number of teeth and the number of teeth of the long tooth block equal to Q, and by providing an auxiliary groove on at least the long teeth.

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 a to 1 and the 12 teeth with a predetermined gap.

The 12 winding grooves of the armature core 4 are marked with A and B in Fig. 1.
Similarly to the C-phase winding group, the three-phase winding group is wound in a form-wound manner (not shown). In other words, the winding AI is wound across the winding grooves a to d. The winding A2 is wound from the winding groove d to g, the winding A3 is wound from the winding groove g to j, and the winding A2 is wound from the winding groove j to a. Line A
4 are wound, and 1 MAI 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 r, the winding B2 is wound from the winding groove f to i, and the winding B2 is wound from the winding groove l to 2. 11iB3 is wound, winding B4 is wound from winding groove l to C, and winding B'1-
84 are connected in series in consideration of the winding direction to form a third winding group. Further, the winding C1 is wound from the winding groove e to h, the winding C2 is wound from the winding groove k to the winding groove k, and the winding C2 is wound from the winding groove k to b. C
3 is wound, and a winding C4 is wound across the winding groove e, and the windings 01 to C4 are connected in series considering the winding direction to form a C-phase winding group. The drive circuit of this embodiment forming the structure is the same as that shown in FIG. 2, and the explanation thereof 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 a tooth is the angle formed by the center of the winding groove at both ends of the tooth. When the number of winding grooves is T = 3 and P = 12 (P is the number of magnetic poles in the field part and P - 4), if they are arranged at equal angular intervals, the effective pitch of each tooth is D = 360°/ T (in this example, D=120'/P-30'), so D
Teeth larger than D will be called long teeth, and teeth smaller than D will be called short teeth. Teeth a-b (represented by the winding grooves at both ends) are short teeth, teeth b-c are short teeth, teeth c-d are short teeth, teeth d-e are long teeth, and teeth e-f are short teeth. Teeth, teeth r-g are short teeth, teeth g
-h is a short tooth, tooth h-4 is a long tooth, tooth i-J is a short tooth, tooth j-
is a short tooth, and -1 is a short tooth, a tooth! -a is a long tooth. That is, the number of long teeth is L-3, and the number of short teeth is M=9. Between winding grooves a and d (a, b, c, d), between winding grooves e and h (e, f, g, h), and between winding grooves i and l (i, In j, Il), only short teeth are partially concentrated, forming a short tooth block consisting of three short teeth (no long teeth included). Similarly, between the winding grooves d and e (d, e) and between the winding grooves and 1 (
h, i) and winding groove 2 to a (2a), only long teeth are partially concentrated, forming a long tooth block consisting of one long tooth (including short teeth). In other words, three sets of short tooth blocks and long tooth blocks are arranged alternately on the circumference. Short teeth a-b, b-c, c-d, e-f, f-
The effective pitch of g, g-hi-j, J-, and ni-1 is
360'/(T+3)=24" or approximately equal. The effective pitch of the long teeth d-e, h-i, and la is equal to or approximately equal to 720"/(T+3)=48@. has been done. That is, the ratio of the effective pitch of the short teeth to the effective pitch of the long teeth is set to R:R+1 (R-1), and each long tooth is provided with one auxiliary groove.
The entire groove of the armature core, which consists of the winding groove and the auxiliary groove, is spaced at equal angular intervals (360 @ / 15-24 @ interval) or approximately at equal angular intervals, with the center of the valley groove (the center seen from the magnetic effect)
is located.

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 one magnetic pole pitch 360°/P of the magnet 3. Therefore, it is only necessary to consider the magnetic non-uniformity of the armature core 4 (magnetic variation caused by the arrangement of the winding groove and the auxiliary groove) with one magnetic pole pitch of the magnet 3 as the basic period, and generally the amount of variation is If , the cogging torque becomes smaller. FIG. 6 shows the phase relationship between the winding grooves a-42 and the auxiliary grooves a' to C' of the armature core 4, with one magnetic pole pitch of the magnet 3 as a basic period.

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

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

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

l is provided with a phase shift of 1/15 of the pitch of one magnetic pole, and its variation range is set to 115 of the pitch of one magnetic pole. Furthermore, a winding groove in which a C-phase winding group is housed;
A phase shift is provided for e and h with a phase difference of 1/15 of one magnetic pole pitch, and the variation range is lT! 17 with single pole pitch
5 has been made.

The A-phase winding groove group (a, d, g, J), the B-phase winding groove group (c, f, i, I!,), and the C-phase winding groove group (b, e , h, k), each having a phase difference of 1/3 of one magnetic pole pitch. Further, the auxiliary grooves a' to C' are located in a phase different from the phase of the winding groove a-2, and the winding groove a
-1 and the entire groove consisting of auxiliary grooves a' to C' is 1/15
The phases are all different with a phase difference of . Figure 7 shows the waveform of the magnetic fluctuation of the armature core 4 due to the winding groove a%N and the auxiliary grooves a' to C'. The magnetic variation changes smoothly. Winding groove a -%-1 and auxiliary grooves a' to C' are 1/1
Since the phases differ by 5, the composite magnetic fluctuation component (alternating current component) is quite small. FIG. 8 shows magnetic fluctuations of the conventional electric motor shown in FIG. Winding grooves a, L g, and J are in phase, and winding grooves c, f, and i
, l have the same phase, and the winding grooves e and h have the same phase, so the composite magnetic fluctuation of the conventional motor shown in Fig. 1 is very large (the conventional motor shown in Fig. 1 For example, auxiliary grooves a' to C
).

Comparing FIG. 7 and FIG. 8, it can be seen that the magnetic fluctuation of the motor of this embodiment is significantly reduced.

As a result, the cogging torque of this embodiment is significantly reduced.

Furthermore, each winding AI, A2 . A3゜A4. B
l, B2. B3. B4. The effective pitch of CI, C2, C3°C4 ranges from (16/15 of 1 magnetic pole pitch) -192 degrees (electrical angle) or less to (415 of 11 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)
, the angle between the winding grooves d and g of A2 is 192"
(1 long tooth and 2 short dentary bones), the angle between the winding groove g-j of A3 is 192" (1 long tooth and 2 short dentary bones), A4 The angle between the winding grooves j and a is 1
92' (one long tooth and two short teeth), the B phase winding group has B1 winding groove c-f.
The angle between them is 192@ (one long tooth and two short dentaries), B
The angle between the two winding grooves r- is 192' (1
(3 long teeth and 2 short dentaries), the angle between the groove i-1 for the wound winding of B3 is 144° (3 short dentaries), for the wound winding of B4 The angle between the grooves 1-c is 192° (one long tooth and two short teeth).If we look at the C-phase winding group, the grooves e-h for the windings in which the CI is wound are The angle between is 144
'(3 short dentary bones), the angle between the wound winding groove h- of C2 is 192''' (1 long tooth and 2 short dentary bones),
The angle between -b and the groove for winding C3 is 192° (
1 long tooth and 2 short dentary bones), the angle between the winding groove b and e of C4 is 192° (1 long tooth and 2 short dentary bones), In this way, if the range of variation of the winding groove in which the @ wire of each phase is housed is reduced (to 1/3 or less of the pitch of one magnetic pole), and the range of variation of the effective pitch of the winding is reduced. (from 192 degrees or less to 144 degrees or more), the winding work becomes easier and automation is 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.
, b I, CI (even if the resultant magnetic fluctuation is smaller than the conventional example shown in Fig. 8). Cogging torque can be reduced by alternately arranging blocks and long tooth blocks.At this time, if the total number of teeth of the short tooth blocks and long tooth blocks of the adjacent strings is different from a multiple of 3, it is possible to reduce the cogging torque. The phase of the teeth can be varied.Also, the overall effective pitch of three consecutive sets of short tooth blocks and long tooth blocks is set equal to (360"/P) ・Q, and one set of adjacent short teeth If the total number of teeth of the block and the long tooth block is made equal to Q, the phase difference between the three-phase winding groups can be made equal to 120 degrees (electrical angle), and the three sets of 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 (possible. Furthermore, the effective pitch of the short teeth and the effective pinch of the long teeth are set to R: R+1 or RjR+3 (R is an integer), and the armature core consists of winding grooves and auxiliary grooves. The cogging torque can be easily reduced by arranging the entire grooves at intervals of 1/R of the effective pitch of the short teeth.Table 1 shows other examples of such a configuration.

Table 1 In the configuration of Table 1 (A), the effective pitch of the short teeth in Fig. 5 is 2 unit angle (l unit angle is 360@/27-13.33')
Table 1: 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. 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 360°/39-9.23°), and the effective pitch of the long teeth is set to 4 unit angles. The configuration shown in Table 1 (C), in which 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, is the fifth
The effective pitch of the short teeth in the figure is 1 unit angle (1 unit angle is 36
0@/21=17.14°), the effective pitch of the long teeth is set to 4 unit angles, auxiliary grooves are provided on the long teeth, and the entire groove consisting of the winding groove and the auxiliary groove is spaced at 1 unit angle intervals. This is what was placed.

Moreover, 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.

Table 2 The configuration of Table 2 (A) consists of a long tooth block consisting of three long teeth and a short tooth block consisting of one short tooth, arranged alternately on the circumference and the short teeth shown in Figure 5. (exchanging the number of long teeth) and the effective pitch of short teeth by 1 unit angle (1 unit angle is 360"
/21-17.14”) and set the effective pitch of the long teeth to 2.
In the configuration shown in Table 2 (B), where an auxiliary groove is provided on the long teeth and the entire groove consisting of the winding groove and the auxiliary groove is arranged at intervals of 1 unit angle, the effective effect of the short teeth is Pitch by 2 units of angle (1 unit of angle is 360°/33=10.91°)
The effective pitch of the long teeth is set to 3 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 arranged at intervals of 1 unit angle.

In the configuration of Table 2 (C), the effective pitch of the short teeth is set to 3 unit angles (1 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 arranged at intervals of 1 unit angle.

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 In the configuration of Table 3 (A), the effective pitch 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 set to 4 unit 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. They are arranged at angular intervals.

In each of the embodiments described above, the number of magnetic poles of the magnet 3 in the field section was set to P=4, but the present invention is not limited to such a case. For example, if the number of magnetic poles of the magnet 3 in the field section is set to P = 8, three-phase windings will be pattern-wound in T = 3P - 24 winding grooves, but 7 Table 4 shows an example in which cogging torque is reduced by alternately arranging three sets of short tooth blocks consisting of short teeth and one long tooth block consisting of one long tooth on the circumference.

(Margin below) The configuration in Table 4 (A) is based on the effective pitch of the short teeth by one 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 shown 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
0"/75=4.8@), set the effective pitch of the long teeth to 4 unit angles, provide auxiliary grooves on the long teeth and short teeth, and make the entire groove consisting of the winding groove and the auxiliary groove 1. They are arranged at unit angle 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'), 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. They are arranged at angular intervals. In the configuration of Table 5 (B), the effective pitch of the short teeth is 2 unit angles (1 unit 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. It is.

The configuration in Table 5(C) has the effective pitch of the short teeth set by 3 unit angles (
One unit angle is 360'/93=3.871'), 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 a groove consisting of a winding groove and an auxiliary groove is created. are arranged at intervals of one unit angle.

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

For example, by combining the embodiment in which P=4 and the embodiment in which P=8, an electric motor in which the number of magnetic poles in the field section is P=121 can be configured. 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, the field part has P-pole field M1 magnetic poles at approximately equal angular intervals (equal angular intervals or approximately equal angular intervals) on the circumference, and a 3-phase magnetic field 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 that is equipped with an armature core that houses three-phase windings, and in which either the field part or 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.

Furthermore, if the sum of the number of teeth in an adjacent pair of short tooth blocks and the number of teeth in a long tooth block is a multiple of 3, the phase of the winding groove can be easily varied, and the cogging torque can be reduced. Effective in reducing Furthermore, the effective pitch of three consecutive sets of 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 pair of short tooth blocks and the number of teeth in a long tooth block is equal to Q, then a three-phase winding group The phase of the winding groove can be easily varied while maintaining the phase between 120 degrees (electrical angle), 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 easily reduced significantly. can(
However, the total number of grooves is not an integral multiple of the number of magnetic poles P).

In the above embodiment, the magnet is placed on the inside and the armature core is placed on the outside (although the relationship may be reversed. May constitute a field part, and others.
Various modifications can be made without changing the spirit of the 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. A diagram showing the phase relationship of the winding grooves when looking at the armature core in the figure, Figure 7 is a diagram showing the magnetic fluctuation of the example shown in Part 5, and Figure 8 is the same as 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-j! ...Winding groove, 6...Teeth, a'-c'...Auxiliary groove, Al to A4. Bl~B4. C1~C4...
...winding wire. Name of agent: Patent attorney Shigetaka Awano

Claims (4)

[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, and three consecutive
When the overall effective pitch of the short tooth block and the long tooth block of a pair is approximately (360°/P)・Q (where Q is an integer of 2 or more), the teeth of the adjacent short tooth block and the number of teeth of the long tooth block is equal to Q, and at least the long teeth are provided with auxiliary grooves. (2) 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, and three consecutive
When the overall effective pitch of the short tooth block and the long tooth block of a pair is approximately (360°/P)・Q (where Q is an integer of 2 or more), the teeth of the adjacent short tooth block and the number of teeth of the long tooth block is equal to Q, and at least the long teeth are provided with auxiliary grooves. (3) 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=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 three continuous teeth blocks are provided.
When the overall effective pitch of the short tooth block and the long tooth block of a pair is approximately (360°/P)・Q (where Q is an integer of 2 or more), the teeth of the adjacent short tooth block and the number of teeth of the long tooth block is equal to Q, and at least the long teeth are provided with auxiliary grooves. (4) 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, the short tooth blocks and the long tooth blocks are arranged alternately on the circumference, and three continuous teeth blocks are provided.
When the overall effective pitch of the short tooth block and the long tooth block of a pair is approximately (360°/P)・Q (where Q is an integer of 2 or more), the teeth of the adjacent short tooth block and the number of teeth of the long tooth block is equal to Q, and at least the long teeth are provided with auxiliary grooves.