JPH02276443A - Motor - Google Patents

Abstract

PURPOSE:To reduce the cogging torque by making winding grooves arranged in an armature core as specified and making the sum of the number of the teeth of a short-tooth block and that of the teeth of the adjacent long-tooth block thereto equal to a certain 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 sum of the number of the teeth of a short-tooth block and that of the teeth of the adjacent long- tooth block thereto is made equal to Q when the effective pitches of the whole of continuous three groups of short-tooth blocks and long-tooth blocks are approx. (360 deg./P).Q, wherein Q is 2 or a larger integer.

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 winding grooves.

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@ 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. An annular magnet 3 is attached to the outer periphery of a ferromagnetic rotor 2 attached to a rotating shaft 1. 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 triad core 4). The armature core 4 is provided with 12 winding grooves 5 at equal angular intervals, and 12 teeth 6 are provided between each winding groove.
are formed, and three-phase windings A1 to A4 . Bl~B4. C1
0 winding AI, A2.~C4 is wound. A3. A4
is wound around three teeth, and both winding grooves in which winding AI is housed have windings A2 and A4, respectively.
One end of the 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 A4 is housed, and one ends of windings A1 and A3 are housed in both winding grooves in which winding A4 is housed. Windings Bl to B4 of other phases. C1
The same applies to ~C4. Hereinafter, A1 to A4 will be collectively referred to as a human-phase winding group, Bl to B4 will be a B-phase winding group, and 01 to C4 will be a C-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, and interlinks with the A, B, and C phase winding groups. A, B, C
There is an electrical phase difference of 120 degrees between the phase winding groups. Here, 180 degrees of electrical angle is 1 magnetic pitch of field part 3
This corresponds to 60°/P (P is the IUI number of the field part) (in this example, since P=4, 90 degrees of mechanical angle is one magnetic pole pitch and corresponds to 180 degrees of electrical angle).

Figure 2 shows the configuration diagram of the drive circuit, Volume f! of Figure 1! Al
-A4 are connected in series in consideration of each winding direction to form an A-phase winding group. Similarly, windings B1-84 are connected in series considering each winding direction to form a B-phase winding group, and windings Cl-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 signal P
I, P2. Output P3. The drive unit 11 receives a command signal F and three-phase signals PL, P2 . P3 is input, and a three-phase sinusoidal current 1 proportional to the product of both is input.
Outputs 1, 12, and 13. 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 (It related to permeance) of the armature core 4 is caused by the winding groove a % l.

Since the winding grooves a-1 of the armature 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 ignition component. becomes. Therefore, based on this, the 24th, 36th, etc.
・Contains harmonic components such as. The cogging torque is
The cogging torque of this conventional example is generated when the magnetic non-uniformity component of the armature core 4 and the harmonic component of the period/waveform of the magnet 3 match (match).
2nd order, 24th order, etc. harmonic components 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. Not. Further, even when a large number of auxiliary grooves are provided, the cogging torque cannot be sufficiently reduced because the basic component of the cogging torque matches 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 (
Equipped with a field part having 111 magnetic windings (P is an even number of 2 or more) at approximately equal angular intervals on the circumference, and an armature core in which 3 phase windings are housed in 3P winding grooves. and 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 between the winding grooves. formed and the effective pitch is D=
It has L long teeth (however, L is an integer) larger than 120°/P and M short teeth whose effective pitch is smaller than D (however, M is an integer), and the long teeth and the short teeth are The number of blocks is L+M=3P L ≧ 3 M ≧ 3, and each of the 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, The tooth blocks 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 The above objective is achieved by making the sum of the number of teeth and the number of teeth of the long tooth block equal to Q.

Further, in the present invention, a permanent magnet material is used to form a field part having field magnetic poles of PM (where P is an even number of 2 or more) at equiangular intervals on the circumference, and a field part having 3P windings. An electric motor is provided with an armature core in which three-phase windings are housed in a service 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 each having a plurality of long tooth blocks each consisting of the long teeth, and the long tooth blocks are arranged alternately on the circumference to the short tooth blocks, and three consecutive long tooth blocks are provided.
& [The overall effective pitch of the short tooth block and the long tooth block of i is (360@/P) ・Q (however, Q is 2
The above object is achieved by making the sum of the number of teeth of the short-toothed broso of the adjacent set and the number of teeth of the long-toothed block equal to Q.

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=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 objective is achieved by making the sum of the number of teeth and the number of teeth of the long tooth block equal to Q.

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. 3 consecutive and alternately arranged on the circumference
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
The above object is achieved by making the sum of the number of teeth of the short tooth block and the number of teeth of the long tooth block of one adjacent set equal to Q when the number of teeth is about 100% (an integer greater than or equal to).

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
The 12 winding grooves a-1 and 12 teeth face each other 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 wound, and evA and Al-A4 are connected in series considering the winding direction to form the A-phase winding group.

Similarly, the winding Bl is wound from the winding groove C to r, the winding B2 is wound from the winding groove f to i, and the winding B1 is wound from the winding groove i to l. The wire B3 is wound, and the winding groove t
A winding B4 is wound from the winding to the winding C, and the windings B1 to B4 are connected in series in consideration of the winding direction to form a third winding group. Further, the S wire 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, a winding C4 is wound across the winding groove e, and the windings 01 to C4 are They are connected in series in consideration of the direction of rotation to form a C-phase winding group. The drive circuit of this embodiment has the same configuration as that 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 a tooth is the angle formed by the center of the winding grooves at both ends of the tooth.The number of winding grooves is T=3・P=12 (P is the number of magnetic poles in the field part and P=4 ), 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 er are short teeth. Tooth, tooth f-g is short tooth, tooth g
-h is a short tooth, tooth h-4 is a long tooth, tooth 1-j is a short tooth, tooth j-
1 is a short tooth, tooth 12-a is a short tooth, and tooth 12-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 the winding grooves a and d (a, b, c, d), between the winding grooves e and h (e, f, g, h), and between the winding grooves i and l (i, In j, j2), 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), between the winding grooves and i (h, i), and between the winding grooves 2 and a (I!,).

In a), only long teeth are partially concentrated, forming a long tooth block consisting of one long tooth (does not include short teeth)
. That is, 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-g.

The effective pitches of g-h, i-j, j-, and k-1 are made equal or approximately equal to 360''/(T+3)=24''. Long tooth de, h-i,
The effective pitch of 1-a is 720@/(T+3)=48″
' is made equal or approximately equal to . That is,
The ratio of the effective pitch of short teeth and the effective pitch of long teeth is R:R+L
(R-1). Furthermore, 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 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 -111Th If the amount of variation is reduced, the cogging torque will be reduced. 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 of the magnet 3 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)=l/l 5 of 1M1 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
/3 or less). Similarly, the winding grooves c, f, and i accommodate the B-phase winding group.

l is 1 (a phase shift is provided with a phase difference of 1/15 of the ff pole pitch, and the variation range is 115, which is one magnetic pole pitch. Furthermore, the C phase winding group is A phase shift is provided in grooves e and h with a phase difference of 1/15 of 1 magnetic pole pitch, and the variation range is 1/15 of 1 magnetic pole pitch.
15. A phase winding groove group (a, d, g,
j) and the B phase winding groove group (c, r, i, jl) and the C phase winding groove group (b, e, h, k) are each 1/30 of one magnetic pole pitch. There is a phase difference. Also, the auxiliary grooves a' to C' are in a phase different from the phase of the winding grooves a to 2.
The entire groove consisting of the winding groove a-1 and the auxiliary grooves a' to C' are all different in phase with a phase difference of 1/15. Figure 7 shows the winding/wire groove a-1 and the auxiliary grooves a' to C'.
The waveform of the magnetic fluctuation of the armature core 4 is shown. The magnetic fluctuation due to each winding groove changes smoothly depending on the opening width of the winding groove.

Since the winding groove a-1 and the auxiliary grooves a' to C' have a phase difference of 1/15, the composite magnetic fluctuation component (AC component) is quite small (Fig. 8). Figure 1 shows the magnetic fluctuations of the conventional motor shown in Figure 1. Winding grooves a, d, g
, j are in the same phase, the winding grooves c, f, i, and l are in the same phase, and the winding grooves e, h, and k are in the same phase, so the composition of the conventional motor shown in Fig. 1 is (The conventional example in Fig. 1 has an auxiliary groove a'
~C' is absent).

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.

Sarani, each volume gA1 of this example. A2. A3゜A4. B
l, B2. B3. B4. The effective pitch of CI, C2, C3°C4 is from (16/15 of 1 magnetic pole pitch) = 192 degrees (electrical angle) or less to (415 of 1 magnetic 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 groove 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), Looking at the winding group of phase B, where the angle between the winding groove j and a of A4 is 192° (one long tooth and two short teeth), the winding of B1 Winding groove c-
The angle between f is 192° (one long tooth and two short teeth),
The angle between the winding groove f-4 of B2 is 192° (
(1 long tooth and 2 short teeth), the angle between the winding groove 1-42 of B3 is 144" (3 short teeth), B4
The angle between the winding grooves 1-c is 192@ (one long tooth and two short teeth). Looking at the C-phase winding group, the angle between the C1 winding grooves e and h is 1.
44''' (3 short dentaries), the angle between the winding groove h- of C2 is 192° (1 long tooth and 2 short dentaries), the winding of C3 The angle between −b and the winding groove 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 fluctuation 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 range of variation in 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.
, b', and c' are eliminated, the resulting magnetic fluctuation is smaller than the conventional example shown in Fig. 8. Generally, by devising the arrangement of the 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 adjacent set of short tooth block and long tooth block is different from a multiple of 3, then
The phase of the teeth can be easily varied. In addition, the total effective pitch of three consecutive sets of short tooth blocks and long tooth blocks is set equal to (360°/P) ・Q, and the total number of teeth in one set of adjacent short tooth blocks and long tooth blocks is If it is equal to Q, the phase difference between the three-phase winding group is 120
degree (electrical angle), and three sets of windings can be arranged evenly.

Also, if an auxiliary groove is provided on at least one long tooth,
The cogging torque reduction effect can be increased (possibly), and the effective pitch of the short teeth and the effective pitch of the long teeth can be set to R:R+1 or R:R+3 (R is an integer). Cogging torque can be easily reduced by arranging the entire grooves of the child core 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 angles (1 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 360°/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 grooves consisting of the winding groove and the auxiliary groove are arranged at one unit angle intervals. The configuration in Table 1 (C) is based on the effective pitch of the short teeth in Figure 5 by 1 unit angle (1 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 winding groove and the auxiliary groove are arranged at intervals of one unit angle.

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 3 sets of long tooth blocks consisting of 3 long teeth and 3 sets of short tooth blocks consisting of 1 short tooth arranged alternately on the circumference. (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'), the effective pitch of the long teeth is set to 2 unit angles, 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. It is. In the configuration shown in Table 2 (B), the effective pitch of the short teeth is set to 2 unit angles (1 unit angle is 360 @ / 33 = 10.91°), and the effective pitch of the long teeth is set to 3 unit angles. An auxiliary groove is provided on the short tooth, and the entire groove consisting of the winding groove and the auxiliary groove is
In the configuration shown in Table 2 (C), which is arranged at unit angle intervals, the effective pitch of the short teeth is 3 unit angles (1 unit angle is 3 unit angles).
60°/33=10.91@), 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 auxiliary groove 1 unit angle. They are arranged at 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 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 pitch of the two long teeth is 2 unit angle and 3 unit angle, 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 of 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-described embodiments, 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 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 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, an auxiliary groove is provided on the long teeth, and 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 (
One unit angle is 360'/65 = 5.538@), 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 groove consists of the winding groove and the auxiliary groove. In the configuration shown in Table 4 (C), in which the whole of
"/75=4.8@), the effective pitch of the long teeth is set to 4 unit angle, 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 unit. They are arranged at angular intervals.

In addition, when the M1 stroke number 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. Place it in
Table 5 shows an example of reducing cogging torque.

The configuration in Table 5(A) has the effective pitch of the short teeth set by 1 unit angle (
1 unit angle is 360''/45=8'), the effective pitch of the long tooth is 2 unit angle, and an auxiliary groove is provided on the long tooth.
The entire grooves consisting of the winding groove and the auxiliary groove are arranged at one unit angular intervals. In the configuration of Table 5 (B), the effective pitch of the short teeth is 2 unit angles (l 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. In the configuration of Table 5(C), the effective pitch of the short teeth is set to 3 unit angles (1 unit angle is 360'/93=3.871'),
The effective pitch of the long teeth is set to 4 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.
They are arranged at unit angle intervals.

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°/T
It has L (however, L is an integer) long teeth that are larger than D, and M (however, M is an integer) short teeth whose effective pitch is smaller than D, 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. , and by increasing the number of short tooth protrusions and long tooth blocks to integral multiples of 3, the cogging torque can be easily reduced.

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 the short tooth block and long tooth block of consecutive 3) Jl is (360'
/P) ・When Q is equal to Q (however, Q is an integer of 2 or more), if the sum of the number of teeth of an adjacent set of short tooth blocks and the number of teeth of long tooth blocks is equal to Q, then ・3 phase Although the Q phase between the winding groups is maintained 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 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 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 portion is not limited to an annular magnet, and may be formed of a plurality of magnetic pole pieces. In addition, various modifications can be made without changing the gist of the present invention.

Effects of the Invention The present invention is a motor in which the number of winding grooves is greater than the number of magnetic poles in the field section, and the cogging torque is significantly reduced by arranging the winding grooves in a special manner. Therefore,
If the present invention is used to construct, for example, an electric motor for driving an intermediate portion of a robot or an electric motor for driving an NC device, 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 the electric 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 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-j! ... Winding groove, 6 ... Teeth, a'-C' ... Auxiliary groove, A1-A4, 81-B4. C1-C4...
・Winding wire. Name of agent: Patent attorney Shigetaka Awano, Haka 1 Hiroshi III
Mawarizu sel ku most

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 An electric motor in which the sum of the number of teeth and the number of teeth of the long tooth block is equal to Q. (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 An electric motor in which the sum of the number of teeth and the number of teeth of the long tooth block is equal to Q. (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 An electric motor in which the sum of the number of teeth and the number of teeth of the long tooth block is equal to Q. (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 An electric motor in which the sum of the number of teeth and the number of teeth of the long tooth block is equal to Q.