JPS62185545A - Rotary electric machine - Google Patents

Abstract

PURPOSE:To reduce a skew amount without increasing the number of slots by performing the skew of S slots obtained by S=l/m (l is integer number in case of 1<=l<=m) when the relation of NSX(M+1)/P=n/m (n, m are integer numbers) holds among the number of slots (NS) and the number of poles (P), and the number of grooves (M) provided on tees. CONSTITUTION:A 4-pole permanent magnet rotary electric machine is composed of a field core 1, permanent magnets 21-24, an armature core 3, an armature winding 4, and tees 51-59, etc. In the rotary poles having 9 of the number NS of slots 31, 4 of the number P of poles and NS/P=n/m=9/4, the S slots obtained by S=l/m=l/4 (where l is integer number in case of 1<=l<m) are skewed. Thus, when 1/4 slots is, for example, skewed, the positional relationship between the pole center line of permanent magnets 21-24 and the center line of the tees 51-59 is so skewed that 1/4 slot is displaced at the end of the axially opposite side, the pole center line is uniformly distributed on a tee pitch to reduce a slot ripple.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method in which an armature winding is housed in an armature core with a semi-closed groove,
For example, A where the armature core or field poles are skewed.
This invention relates to a rotating electrical machine such as a permanent magnet rotating electrical machine used in a C servo motor.

[Conventional technology]

In small to medium capacity induction machines, synchronous machines, etc., armature cores with semi-closed grooves, which are easy to accommodate and fix coils, have been widely used. When such a semi-closed groove iron core is used, the so-called slot ripple occurs in which the permeance of the magnetic circuit pulsates due to the influence of the opening. This throttle ripple appears as a harmonic component of cogging torque or induced voltage, and is a cause of deterioration in performance. In recent years, AC servo motors have come to be used as drive devices for robots and machine tools, and low rotational ripple and torque ripple have become important factors, and a reduction in slot ripple is particularly desired. There is.

Most of these AC servo motors are synchronous type motors using permanent magnets, and as shown in Figure 5, there are usually multiple The rotor is made up of a rotor with magnetic poles attached to it, and a stator with an armature winding 0) housed in an armature core (2) in a semi-closed slot provided around the rotor. In a servo motor having such a configuration, it is usually effective to skew the armature core by one slot to reduce slot ripple.

[Problem that the invention seeks to solve]

As described above, in order to reduce slot ripple, it is effective to skew one slot, but this skew has the following problems. First, the slot inner surface of the laminated core becomes stepped, the slot area decreases, the space factor increases, and the winding insertion workability deteriorates. Second, since the winding must be inserted in an involute curve, workability deteriorates. Thirdly, armature copper loss increases because the winding length becomes longer. In addition, when skewing the permanent magnet of the field, it is necessary to prepare a number of magnet molds depending on the amount of skew, and it is difficult to manufacture a flat motor with a short axial length due to the large skew angle. It is.

Because of the above-mentioned problems, it would be better to use an armature core with a large number of slots that can reduce the skew amount by one slot, but it may reduce the number of turns of the winding or reduce the width of the teeth part. In many cases, it is not possible to increase the number of slots due to design constraints, manufacturing problems, workability, cost, etc.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a rotating electric machine that can reduce the amount of skew without increasing the number of slots.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a rotating electric machine in which the armature winding is housed in a semi-closed slot of the armature core and the armature core or the field magnetic poles of the rotor are skewed. M grooves (M is O or an even number) are provided on the surface of the teeth facing the rotor, and Ns
(M + ], ) / P = n/m (n and m are mutually prime integers, m>1), then S2Q/
S score 8 found by m (1≦Qcum, Q is an integer)
It is characterized by causing a minute skew.

[Effect]

By taking the above measures, the distribution of the center line of each magnetic pole is uniformly distributed over one slot pitch, and the influence of slot ripple can be suppressed with a skew of 8 minutes of S-scott, which is less than 1 slot. Can be removed.

[Embodiments of the invention]

Example 1 A first example of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram showing a cross section of a four-pole permanent magnet rotating electrical machine according to this embodiment. The windings are shown for only one slot, and the others are omitted for the sake of simplification, but they are similar to FIG. 5. It is similar. In Fig. 1, ■ is the field core, (21) to (24)
) is the permanent magnet that constitutes the magnetic pole, (3) is the armature core, (
51) to (59) are teeth, the number of slots N5 = 9, the number of poles P = 4, and when m and n are mutually prime integers,
N3/P = n/m = 9/4. In a rotating electric machine with such a cross section, S = fl/m = l/4 (1≦
A skew of 8 minutes is performed as determined by Q<, m, and fl are integers). That is, 1/4.1/2 or 3
/4 slots worth of skew will be performed.

Next, the operation of this first embodiment will be explained.

This shows the case where 1/4 slot skew is performed on the rotating electrical machine shown in FIG. In FIG. 2(a), the broken lines indicate the magnetic pole center lines of the permanent magnets (21) to (24), and the solid lines indicate the center lines of the teeth (51) to (59).

The positional relationship of FIG. 1 in FIG. 2(a) is at the end "A'"
corresponds to 1/4 at the axially opposite end "B Fl"
The relative positional relationship between the solid line and the broken line is skewed by the amount of the slot. FIG. 2(b) shows the distribution of the magnetic pole center lines (dashed lines) in FIG. It is distributed within the width shown by the arrow, and the total of the four poles is uniformly distributed over one tooth pinch as shown by T.

Furthermore, since the total distribution T of the four poles is constant regardless of the position of the rotor, the change in magnetic resistance is constant in total.

In other words, it is possible to cancel the slot ripple by a 1/4 slot skew. Figure 3 is an explanatory diagram of the case where 1/2 slot skew is performed on the rotating electrical machine shown in Figure 1. Similarly to Figure 2, Figure 3 (a) shows the relative relationship between the magnetic poles (broken lines) and teeth (solid lines). Figure 3 (b) shows the positional relationship.
shows the distribution of magnetic poles at one tooth pitch. The distribution T of the 4-pole 1-to-tal shown in FIG. 3(b) is also uniformly distributed on the 1-teas pitch and does not depend on the position of the rotor, so that the change in magnetic resistance is constant in total. That is, it is possible to cancel the slot ripple by the skew of 1/2 slot. Also, in the case of a 1/2 slot skew, there are 2 poles at 1 tooth pitch 1-.
Since the distribution is overlapping, it is more advantageous than the 1/4 slot skew in terms of errors such as geometric misalignment of the magnetic poles and teeth, but on the other hand, the amount of skew is twice as large. Furthermore, although not shown, the same explanation can be given to the case of skew of 3/4 slot. It is possible to eliminate the influence of slot ripple with a small amount of skew.

The above is an example of a 9-slot armature core and a 4-pole field, but generally there is N3/P between the number of slots Ns and the number of poles P.
=n/m (n and m are mutually prime integers m) 1
), if we perform skew for S slots expressed as S=ρ/m (1≦Q×m: Q is an integer), we get
As in FIGS. 2 and 3, the total magnetic pole center line of each pole is uniformly distributed on the 1-tooth pitch, making it possible to eliminate the influence of slot ripple. Table 1 shows m when the number of slots Ns is 6 to 36° and the number of poles P is 2.4 and 6.8.
, and the number of slots q per phase per pole when three sets of armature windings are accommodated. ☆ in Table 1
The mark indicates a commonly used integer slot where q is an integer; in this case, all m values are 1, and at least 1
Unless the skew is equal to the slot, the influence of =7-slot ripple cannot be eliminated. In Table 1, select a combination where m > 1 and calculate 1/m~
By performing skew for (m-1)/m slots, it is possible to eliminate slot ripple with a gap of less than one slot. However, when the 3-set type machine winding is housed in the iron core with the selected number of slots, q = Ns/3P = j/k
(j and k are mutually prime integers) denominator k of q
If is divisible by 3, it is not possible to wind the three-phase windings in a perfectly balanced manner.

Therefore, if k is not divisible by 3 and a combination is selected such that gm is the largest (0 mark in Table 1), an armature with the least amount of skew, no slot ripple, and three-phase balance will be constructed. It becomes possible to do so.

Margin table below - 1 Embodiment 2 Figure 4 is a diagram showing a second embodiment of the present invention.The points that differ from the embodiment in Figure 1 are teeth (51) of the armature core ■.
(59) Two grooves 0 are provided on the surface facing the gap. These two grooves 0 are provided so that the change in magnetic resistance at the teeth is evenly divided into three, and the apparent
The slot iron core has the same change in magnetic resistance as the 27 slot iron core. For this reason, a 9-slot core requires a skew of at least 1/4 slot, but this is reduced to a 1/4 slot skew in a 27-slot core. Generally, by providing an even number (M) of grooves to uniformly divide the magnetic change in the teeth into an odd number of grooves, an iron core with the number of slots Ns looks like Ns×(M+1) slots, and the gap 1 It becomes possible to reduce the amount.

The case where M=O corresponds to the first embodiment.

〔Effect of the invention〕

As explained above, according to the present invention, the relationship between the number of slots Ns, the number of poles P, and the number of grooves M (M is O or an even number) provided on the teeth is NsX(M+1)/P=n/m (n and m are mutually prime integers, and when m>1), S=l
/m (1≦Q<m: Q is an integer) by implementing the 8-minute skew of the S thrower, the influence of slot ripple can be removed with a 8-minute skew of the S thrower, which is less than one slot.

Therefore, it is possible to obtain a rotating electrical machine that can reduce the amount of skimming without significantly increasing the number of slots.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view schematically showing the first embodiment of the present invention, FIGS. 2 and 3 are explanatory diagrams showing the operation of the first embodiment,
FIG. 4 is a cross-sectional view schematically showing the second embodiment, and FIG. 5 is a cross-sectional view schematically showing a conventional rotating electric machine. 1... Field iron core, 2, 21.22.23.24... Permanent magnet, 3...
Armature core, 4...Armature winding, 5.51~5
9...Teeth, 6.Groove. ＼ Ri

Claims (2)

[Claims] (1) In a rotating electrical machine in which the armature winding is housed in a half-closed slot in the armature core and the field magnetic poles of the armature core or rotor are skewed, the surface of the teeth of the armature core facing the rotor M grooves (M is 0 or an even number) are provided, and the number of slots N_s in the armature core, the number M of grooves in the teeth, and the number of poles P.
When there is a relationship between N_s×(M+1)/P=n/m (n and m are mutually prime integers and m>1), S=l/
A rotating electrical machine characterized by having a skew of S slots determined by m (1≦l<m, where l is an integer). (2) The number of phases is 3, N_s×(M+1)/3P=j/
Claim 1, characterized in that the number of slots N_s is selected so that when k (j and k are mutually prime integers), k is not divisible and m is the largest value.
Rotating electric machine as described in section.