JPS6142259A - Motor - Google Patents

Abstract

PURPOSE:To reduce a cogging torque by specifying the disposition of a groove for windings more than the number of poles of a field. CONSTITUTION:A magnet 3 mounted on a rotor 2 has field poles of P poles (P is even number), and an armature core 4 has teeth formed between grooves (a)- (l) for T pieces (T is P or larger integer number) of windings wound with windings of 3 phases. The core 4 has L pieces (L is integer number) of long teeth at the effective pitch larger than D=360 deg./T, and M pieces (M is integer number) of short teeth at the effective pitch smaller than D, and the numbers of the long and short teeth are set to L>=3, M>=3. Short tooth blocks of two or more short teeth and long tooth blocks of at least one long tooth are the same number, the short and long tooth blocks are alternately disposed on the circumference, and the numbers of the long and short blocks are integer number magnification of 3.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electric motor having an armature core having more winding grooves than the number of magnetic poles in a field section.

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 force for industrial robots and N0 equipment. However, in such a motor, cogging torque occurs due to interaction between the magnetic poles of the field section and the winding grooves of the armature core. Hereinafter, this will be explained with reference to the drawings, taking a plasticine type 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 to form a field section. 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 armature iron 1
4). The electric machine and child core 4 are provided with 12 winding grooves 5 at equal angular intervals, and 12 teeth 6 are formed between each winding groove to accommodate a 34' winding. A1-A4, 81-B4
, 01 to C4 are wound. Winding AI, A2. A
3. A4 is wound so as to surround three teeth, and both winding grooves in which the winding A1 is housed each contain a winding A4.
2 and one end of A4 paper are stored. Similarly, both winding grooves in which winding A2 is stored have windings A1 and A3 respectively.
One end is stored in both winding grooves in which winding A3 is stored, and one ends of winding man 2 and A4 are stored in both winding grooves in which winding A4 is stored, respectively. winding person 1
and one end of the A3 paper are stored. Windings B1 to B of other phases
The same applies to 4.01 to C4. Below, A1-A
4 are collectively referred to as a human-phase winding group, B1 to B4 are a B-phase winding group, and C1 to C4 are a C-phase winding group. The magnetic flux generated by the magnet 3 in the field s flows into or out of each tooth of the armature iron 11) and 4, and interlinks with the winding groups of the human, B, and C phases. There is an electrical phase difference of 120 degrees between the A, B, and C phase winding groups. Here, 180 degrees of electrical angle corresponds to one magnetic pole pitch of the field part 3 e o 0/P (P is the number of magnetic poles of the field part) In this example, since P=4, the mechanical angle is 9
Q degree is one magnetic pole pitch, which corresponds to 180 electrical degrees).

FIG. 2 shows a configuration diagram of the drive circuit. Winding A1~ in Figure 1
A4 are connected in series in consideration of each winding direction to form a human phase winding group. Similarly, windings B1 to B4 are connected in series considering each winding direction to form a B-phase winding group,
The windings 01 to C4 are connected in series in consideration of each winding direction to form a C-phase winding group. The three-phase winding group is connected in a star shape, and its terminals are connected to the drive section 11. The position detection unit 12 detects the position of 30 rotations of the magnet, and generates a three-phase sinusoidal signal P1 that changes as the magnet 30 rotates.
．． P2. Output P3. The drive unit 11 receives a command signal F.
and the three-phase signal P1. of the position detection section 12. P2. P3 is input, and a three-phase sinusoidal current 11 proportional to the product of both is input.
．． Outputs 12.13. As a result, currents 11.12. ．． 13 and the magnetic flux of the magnet 3, a rotational force in a predetermined direction is generated.

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/ref is caused by the magnetic energy stored in the magnetic field between the field part and the armature core changing in accordance with the relative rotation of the two. especially,
This occurs in relation to both the magnetic poles of the field part and the grooves of the armature core, and as shown in Figure 1, the magnet 3 of the field part and the armature core 4
When both have magnetic periodicity, a cogging torque of a component (matching component) that exists in common in both occurs. FIG. 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 related to the square of the magnetic flux density, the basic harmonic component of the magnetic period/waveform of the magnet 3 in the field part with the characteristics shown in Fig. 4 is the fourth harmonic. It becomes a wave 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 1L-1. Since the winding grooves IL~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 order component. becomes. Therefore,
Based on this, the 24th, 36th, etc.
Contains harmonic components such as Cogging torque occurs 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), so the cogging torque of this conventional example is the 12th
Harmonic components such as the 24th order, 24th order, etc. are generated.

The 12th order component of the cogging)/ref is directly related to the fundamental component of the magnetic inhomogeneity of the armature core 4 caused by the 12 winding grooves. Generally, the fundamental component of the armature core 4 is considerably larger than other harmonic components. As a result, very large cogging torque occurred 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, it is necessary to make the basic order of the cogging tonnage considerably high, and many auxiliary grooves must be provided in the armature core. Not practical. Further, even when many auxiliary grooves are provided, the basic component of the cogging torque matches the basic component of the armature core, so the cogging torque cannot be sufficiently reduced.

Purpose of the Invention The present invention takes these points into consideration and significantly reduces cogging torque in a motor in which the number of winding grooves in the armature core is greater than the number of magnetic poles in the field section.

Structure of the Invention The present invention includes a field part having P poles (P is an even number) field magnetic poles at equiangular intervals or approximately equiangular intervals on the circumference, and T windings (T is an integer larger than P). An electric motor comprising an armature core in which three-phase windings are heavily wound in a wire groove, and one of the field part and the armature core is rotatable relative to the other, The armature core has an effective pitch of D = 360'/
It has L long teeth larger than T (L integer) and M short teeth whose effective pitch is smaller than D (M is an integer), and the number of the long teeth and short teeth is L ≧3 M ≧3 and an equal 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 the long tooth blocks are arranged alternately on the circumference. , and the above object is achieved by making the numbers of the long tooth blocks and the short tooth blocks each an integral multiple of 3.

Furthermore, in the present invention, a field portion having P-pole (P is an even number) field magnetic poles at equal intervals or approximately equal angular intervals on the circumference;
The armature core includes T winding grooves (T is an integer larger than P) and an armature core in which three-phase windings are wound heavily, and one of the field part and the armature core is connected to the other. In this motor, the armature core has an effective pitch 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 the long teeth and short teeth is L ≧3 M ≧3 and an equal number of short tooth blocks consisting of at least one short tooth and long tooth blocks consisting of two or more long teeth, and the short tooth blocks and the long tooth blocks are arranged alternately on the circumference. , and the above object is achieved by making the number of the long tooth blocks and the short tooth blocks each an integral multiple of three.

DESCRIPTION OF EMBODIMENTS FIG. 5 is a developed plan view of essential parts representing an embodiment of the present invention. In FIG. 6, the magnet 3 attached to the rotor 2 has four magnetic poles at equal angular intervals, and the armature core 4
012 winding grooves I! It faces L~1 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.
, three-phase winding groups are wound in multiple layers similarly to the C-phase winding group (not shown). That is, the winder 1 is wound from the winding grooves a to d, the winder 2 is wound from the winding grooves d to g, and the winder 2 is wound from the winding grooves g to co. The winding A3 is wound, the winding 4 is wound from the winding groove to the winding groove A, and the winding operators 1 to 4 are connected in series considering the winding direction. It forms 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 f to 1, and the winding B2 is wound from the winding groove f to 1. #1lB3 is wound, winding B4 is wound from winding groove 1 to C, and winding B1 to C are wound.
B4 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. is formed. 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. 6, the winding groove I of the armature core 4 is
L to 1 are arranged at non-uniform intervals to make the effective pitch of the teeth formed between the winding grooves 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・P=12 (P is the number of magnetic poles in the field part and pP=a), when arranged at equal angular intervals, the effective pitch of each tooth is D=360°' /T(
In this example, D=j20°/P=30°), so we will call both full-length teeth larger than D, 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-a are short teeth, teeth C-d are short teeth, teeth d-e are long teeth, and teeth θ-f are short teeth. Tooth, tooth f-g is short tooth, tooth g
-h is a short tooth, tooth h-i is a long tooth, tooth i-j is a short tooth, tooth j-
is a short tooth, tooth -1 is a short tooth, and tooth 1-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 to d (a, b, c, d), between the winding grooves e to h (θ, f, g, h), and between the winding grooves l to 1
Between (1+] r k + 1), only short teeth are partially concentrated, forming a short tooth pro-7ri consisting of three short teeth (no long teeth included). Similarly, the winding groove d
to e (d, e) and between the winding groove and the groove (h, i
) and winding grooves l to a (1°a), only long teeth are partially concentrated, forming 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 of a circle.

Short teeth a-b, b-c, c-6, e-f, f
-g.

The effective pitch of g−hr i−j r j −k r k−1 is equal to or approximately equal to 360′/(T+3)=24°. Long tooth de, h-i,
The effective pitch of l-& is 7200/(T+3)=4
It is made equal or approximately equal to 8°. That is,
The ratio of the effective pitch of short teeth to the effective pitch of long teeth is R:R+1
(R=1). In addition, 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 at equal angular intervals (36Q0/15=24° intervals) or approximately at equal angular intervals. The center of each port (the center seen from the magnetic effect) is located at .

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 3607P of the magnet 3. Therefore, it is only necessary to consider the magnetic non-uniformity of the armature core 4 (magnetic fluctuations caused by the arrangement of the winding grooves and auxiliary grooves) using one magnetic pole pitch of the magnet 3 as the basic period. If it is made smaller, the cogging torque becomes smaller. Winding groove +a of armature core 4 with one magnetic pole pitch of magnet 3 as the basic period
1 and the auxiliary grooves a' to C' are shown in FIG. Winding groove that accommodates the human phase winding group' r d
r g r ] is 1/(T+3)=1/ of one magnetic pole pitch
A phase shift is provided with a phase difference of 15 (winding grooves a, d
+g+] differs in four locations), and its variation range is 3/15 of one magnetic pole pitch=115 (1/3 or less of one magnetic pole pitch). Similarly, the winding grooves c, f, i, and l, which house the B-phase winding group, are provided with a phase shift of 1/16 of the pitch of one magnetic pole, and the variation range is that of the pitch of one magnetic pole. 115. Furthermore, the winding grooves e and h in which the C-phase winding group is housed are provided with a phase shift of 1/16 of the pitch of one magnetic pole, and the variation range is 115 of the pitch of one magnetic pole. is being done. The human phase winding groove group (Otsu, d, g, j), the B phase winding groove group (c, f, i, l), and the C phase winding groove group (b,
e.

There is a phase difference of 1/3 of one magnetic pole pitch between h and k). Further, the auxiliary grooves a' to C' are located in a phase different from the phase of the winding grooves a to 1, and the entire groove consisting of the winding grooves a to 1 and the auxiliary grooves a' to C' is 1/ The phases are all different with a phase difference of 15.

In FIG. 7, the winding grooves a to 1 and the auxiliary grooves a' to C' are shown]1.
2 shows the waveform of magnetic fluctuations in the armature core 4. The magnetic fluctuation due to each winding groove changes smoothly depending on the opening width of the winding groove. Winding grooves a~1 and auxiliary grooves a'~C
' have a phase difference of 1/15, so the composite magnetic fluctuation component (alternating current component) is very small. FIG. 8 shows magnetic fluctuations of the conventional electric motor shown in FIG. Winding groove a.

d, g, and j are in the same phase, and the winding grooves c, f,
i.

l is in the same phase, and the winding grooves e and h are in the same phase, so the composite magnetic fluctuation of the conventional motor shown in Fig. 1 is very large (Fig. 1). In the conventional example, auxiliary grooves a' to C'
(No) 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, person 2, and A3 of this example.

A4. B1. B2. B3. B4, 01.02゜03.0
The effective pitch of 4 is (16715 of 1 magnetic pole pitch) = 1
From 92 degrees (electrical angle) or less (415 degrees of 1 magnetic pole pitch)
-144 degrees (electrical 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 stored, and the winding groove d in which the winding is wound is A2.
The angle between -g is 192° (1 long tooth and 2 short walls)
, the angular variation between A3's winding groove g and co is 192° (one long tooth and two short walls), and the angle difference between A4's wound winding groove j and a. The angle is 192° (one long tooth and two short walls). Looking at the B-phase winding group, the angle between the B1 winding groove c- is 192° (one long tooth and two short teeth), and the B2 winding groove is 192° (one long tooth and two short teeth). Winding groove f-
The angle between i is 192° (1 long tooth and 2 short teeth)
, the angle between the winding grooves i-1 of B3 is 144° (3 short thicknesses), and the angle between the winding grooves 1-0 of B4 is 192° (1 (long teeth and two short pieces). Looking at the winding group of phase C, the angle between the winding grooves e and h in which C1 is wound is 144° (three short thicknesses), and C
The angle between the two winding grooves h- is 192° (
(1 long tooth and 2 short walls), the angle between -b in the winding groove where C3 is wound is 192° (1 long tooth and 2 short walls), The angle between the winding groove b and e is 1
92° (one long tooth and two short pieces). In this way, if the range of variation of the winding groove in which the windings of each phase are 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 operation 3 becomes easier and automation is possible.

In the embodiment shown in FIG. 6 described above, an auxiliary groove was provided at the tip of the long tooth, but the auxiliary groove is not necessarily necessary.

Even if 7, bI, and CI shown in FIG. 7 are eliminated, the composite magnetic variation is smaller than that of the conventional example shown in FIG. 8. In general, by devising the arrangement of long teeth and short teeth and alternately arranging short tooth blocks and long tooth blocks of integral multiples of 3,
Cogging torque can be reduced. At this time, if the total number of teeth in a pair of adjacent short tooth blocks and long tooth blocks is different from a multiple of three, 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 (3600/P)■Q, and the total number of teeth in one set of adjacent short tooth blocks and long tooth blocks is Q. If it is made equal to , the phase difference between the three-phase winding groups can be made equal to 12 degrees (electrical angle), and the three sets of windings can be equally arranged.

Well, if you provide an auxiliary groove on at least one long tooth,
The cogging torque reduction effect can be increased. Furthermore, the effective pitch of short teeth and the effective pitch of long teeth are R: R+I L
If L< is R2R+3 (R is an integer) and the entire armature core groove consisting of the winding groove and auxiliary groove is arranged at an interval of 1/R of the effective pitch of the short teeth, it is easy. Cogging torque can be reduced. Other examples of such configurations are shown in Table 1.

Table 1 The configuration of Table 1 (mu) is based on the effective pitch of the short teeth in Figure 5 by 2 units of angle (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 intervals of 1 unit angle. The configuration of Table 1CB) is as shown in Fig. 6, where the effective pitch of the short teeth is set to 3 unit angles (one unit angle is 36o0/39.=9.23°), the effective pitch of the long teeth is set to 4 unit angles, and the short teeth are set to 4 units of angle. Auxiliary grooves are provided on the teeth and long teeth, and the entire grooves consisting of the winding groove and the auxiliary groove are arranged at one unit angular intervals. The configuration of Table 1(C) is the fifth
The effective pitch of the short teeth in the figure is 1 unit angle (1 unit angle is 36
00/21 = 17.14°), change the effective pitch of the long teeth by 4 units of angle, provide auxiliary grooves on the long teeth, and make the entire groove consisting of the winding groove and the auxiliary groove at 1 unit angle intervals. This is what was placed.

However, even if the long tooth block does not consist 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 and the short teeth shown in Figure 6. (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 2 unit angles (1 unit angle is 360'/33 = 10.91°), and the effective pitch of the long teeth is 3 unit angles. Auxiliary grooves are provided on the short teeth, and the entire groove consisting of the winding groove and the auxiliary groove is arranged at one unit angle intervals.

In the configuration of Table 2 (C), the effective pitch of the short teeth is set to 3 unit angles (1 unit angle is 3600/33 = 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.

Further, 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 and the effective pitch of the two long teeth are each 2 units angle 1.1
and 3 unit angles, auxiliary grooves are provided on the long teeth, and the entire grooves consisting of the winding groove and the auxiliary groove are arranged at 1 unit angle intervals. The configuration in Table 3 (B) has two fibrillation pitches of 4 and 5 units, 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. They are arranged at unit angle intervals.

In each of the embodiments described above, the number of magnetic poles of the magnet 3 in the field section was set to 4, but the present invention is not limited to such a case. For example, if the number of magnetic poles of magnet 3 in the field part is P = 8 VC, T-3P-24
The 3+th winding will be wound heavily in each of the winding grooves,
Table 4 shows an example of reducing cogging torque by arranging short toothed teeth consisting of 7 short teeth and long toothed teeth consisting of 7 long teeth alternately on the circumference. show.

(Margin below) The configuration of Table 4 (A) has the effective pitch of the short teeth set by 1 unit angle (
1 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 (
One unit angle is 360'/65 = 5.638°), 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. are arranged at intervals of one unit angle. In the configuration of Table 4 (C), the effective pitch of the short teeth is 3 unit angles (1 unit angle is 360
'/75=4.8°), 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 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=s, 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 6 shows an example of reducing the cogging)/ref.

The configuration in Table 6(A) has the effective pitch of the short teeth set by 1 unit angle (
One unit angle is 3600/4528 degrees), 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 1 unit angle. They are arranged at intervals. In the configuration shown in 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 the groove consists of the winding groove and the auxiliary groove. 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 with P=4 and the embodiment with P=8, it is possible to configure an electric 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. In general, a field part has P poles (P is an even number) field magnetic poles arranged at equiangular intervals or approximately equiangularly variable intervals on the circumference, and T (T is an integer greater than P) winding grooves. In the case of an electric motor equipped with an armature heavily wound with three-phase windings, an iron and a sowing device, and either one of the field part and the armature core is rotatable relative to the other, the electric machine The child core has L long teeth (L is an integer) with an effective pitch larger than D=360°/T and M short teeth (M is an integer) with an effective pitch smaller than D, and the long teeth and the number of 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,
Cogging torque can be easily reduced by arranging the short tooth blocks and the long tooth blocks alternately on the circumference, and making the numbers of the long tooth blocks and the short tooth blocks each an integral multiple of 3. .

The field also includes a field part having P magnetic poles (P is an even number) at equiangular intervals or approximately equiangularly variable intervals on the circumference, and T magnetic poles (T is P
a larger integer) and a winding groove [an armature core in which three-phase windings are heavily wound; one of the field part and the armature core is rotatable relative to the other In the case of an electric motor, the armature core has an effective pitch of D=36.
It has L long teeth (L is an integer) larger than 0'/T and M short teeth whose effective pitch is smaller than D (M is an integer), and the number of the long teeth and short teeth is L ≧3. M ≧3, and the same number of short tooth blocks consisting of at least one short tooth and long tooth blocks consisting of two or more long teeth are provided, and the short tooth blocks and the long tooth blocks are alternated on the circumference. The cogging torque can be easily reduced by arranging the long tooth block and the short tooth block by making each number an integral multiple of three.

At this time, when the effective pitch of three consecutive sets of short tooth blocks and long tooth blocks is equal to (3600/P)■Q, the number of teeth in the adjacent short tooth block and the number of teeth in the long tooth block If the total number of teeth in an adjacent pair of short tooth block and long tooth block is made to be different from a multiple of 3, the phase difference between the three-phase winding group will be 120.
The phase of the winding groove can be easily varied while maintaining the same electrical angle, which is effective in reducing cogging torque. Furthermore, by providing an auxiliary groove on at least one long tooth, the ratio of the effective pitch of the short teeth to the effective pitch of the long teeth is R:R+
1 (R is an integer), and if the entire armature core groove consisting of the winding groove and auxiliary groove is arranged at an interval of 1/R of the effective pitch of the short teeth, cogging torque can be achieved with a small number of auxiliary grooves. (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 inside and f is placed outside.
Although the %Q cores are arranged, the relationship may be reversed. Furthermore, the field portion is not limited to an annular magnet, and the field portion may be composed of a plurality of magnet 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, for example, a motor for driving an intermediate part of a robot or a motor for driving an IC device is configured based on the present invention, highly accurate rotational drive and position control will be possible.

[Brief explanation of the drawing]

Figure 1 is a structural diagram of the main parts of a conventional electric motor, Figure 2 (d) is a configuration diagram of its drive circuit, Figure 3 is a plan development of the electric motor in Figure 1, and Figure 4 is the magnetic flux of the magnet in the field section. Figure 5 is a diagram showing the distribution of density, Figure 5 is a plan development view of a motor according to an embodiment of the present invention, Figure 6 is the winding when looking at the armature core in Figure 5 with one magnetic pole pitch of the magnet as the basic period. FIG. 7 is a diagram showing the magnetic fluctuation height of the embodiment shown in FIG. 5, and FIG. 8 is a diagram showing the magnetic fluctuation height of the conventional example shown in FIG. 1. Yes. 2...Rotor, 3... -Magnet, 4...
Armature core, 6. &~l... Winding groove, 6...
Teeth, a'-C' Auxiliary groove, A1-Person 4. B1~B4
, 01-C4... winding. Name of agent: Patent attorney Toshio Nakao and one other person

Claims (10)

[Claims] (1) A field part having P poles (P is an even number) field magnetic poles at equiangular intervals or approximately equiangular intervals on the circumference, and T (T is an integer greater than P) winding grooves. An electric motor comprising an armature core in which three-phase windings are heavily wound, and either one of the field part and the armature core is rotatable relative to the other, and the armature core has an effective pitch of D=36
It has L long teeth (L is an integer) larger than 0°/T and M short teeth (M is an integer) whose effective pitch is smaller than D, and the number of the long teeth and short teeth is L≧3. M≧3, and 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 are provided, and the short tooth blocks and the long tooth blocks are alternated on the circumference. , and the number of the long tooth blocks and the short tooth blocks are each an integral multiple of 3. (2) When the overall effective pitch of three consecutive short tooth blocks and long tooth blocks is equal to (360°/P)■Q,
2. The electric motor according to claim 1, wherein the sum of the number of teeth of the short tooth block and the number of teeth of the long tooth block in an adjacent set is equal to Q. (3) The electric motor according to claim (1), characterized in that the total number of teeth in a pair of adjacent short tooth blocks and long tooth blocks is different from a multiple of three. (4) The electric motor according to claim (1), characterized in that at least one long tooth is provided with an auxiliary groove. (5) The ratio of the effective pitch of short teeth to the effective pitch of long teeth is R:
R+1 (R is an integer), and the entire armature core 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 electric motor described in scope item (4). (6) A field part having P poles (P is an even number) field magnetic poles at equiangular intervals or approximately equiangular intervals on the circumference, and T (T is an integer greater than P) winding grooves. An electric motor comprising an armature core in which three-phase windings are heavily wound, and either one of the field part and the armature core is rotatable relative to the other, and the armature core has an effective pitch of D=3
It has L long teeth (L is an integer) larger than 60°/T and M short teeth (M is an integer) whose effective pitch is smaller than D,
The numbers of the long teeth and short teeth are L≧3 and M≧3, and the short teeth block has the same number of short teeth blocks consisting of at least one short tooth and the same number of long teeth blocks consisting of two or more long teeth, and the short teeth An electric motor characterized in that blocks and the long tooth blocks are arranged alternately on a circumference, and the numbers of the long tooth blocks and the short tooth blocks are each an integral multiple of 3. (7) When the overall effective pitch of three consecutive short tooth blocks and long tooth blocks is equal to (360°/P)・Q,
6. The electric motor according to claim 6, wherein the sum of the number of teeth of the short tooth block and the number of teeth of the long tooth block in an adjacent set is equal to Q. (8) The electric motor according to claim (6), characterized in that the total number of teeth in a pair of adjacent short tooth blocks and long tooth blocks is different from a multiple of three. (9) The electric motor according to claim (6), characterized in that at least one long tooth is provided with an auxiliary groove. (10) The ratio of the effective pitch of short teeth to the effective pitch of long teeth is R
:R+1 (R is an integer), and the entire armature core groove consisting of a winding groove and an auxiliary groove is arranged at an interval of 1/R of the effective pitch of the short teeth. The electric motor described in paragraph (9) of the scope of