JP2619674B2 - Permanent magnet type stepping motor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a permanent magnet type stepping motor, and more particularly to an improvement of a permanent magnet type stepping motor used for driving peripheral devices of an electronic computer and office equipment. .

[Problems to be solved by the invention]

FIGS. 2 (a) and 2 (b) show one embodiment of a conventional permanent magnet type stepping motor.

2 (a) and 2 (b), 1 is a stator housing, 2 is a stator iron core, 3 is a stator winding, and 4 and 4 are end brackets.

A plurality of stator magnetic poles (eight in the illustrated example) 2-1 to 2-8 are radially implanted on the inner periphery of the stator core 2, and a plurality of pole teeth 2 are provided at the tip of each stator magnetic pole. -20 are provided at an equal pitch, and windings 3-1 to 3-
8 are wound.

On the outer circumference of the rotor magnetic poles 7 and 8, pole teeth 7-10 and 8-10 are respectively provided over the entire circumference at the same pitch as the pole teeth 2-20 provided on the stator magnetic poles. The positions of the respective pole teeth are shifted by 1/2 pitch, are fixed integrally with the rotor shaft 6 with the permanent magnet 9 interposed therebetween, and are fixed to the pole teeth 2-20 of the stator by bearings 5,5. And the pole teeth 7-10 and 8-10 of the rotor are rotatably supported by facing each other via a gap.

The stator windings are usually connected in series with windings wound symmetrically with respect to the axis to form four sets of windings, and each winding is energized sequentially, so that the energized winding is wound on the magnetic pole Are magnetized and the rotor pole teeth opposed to the pole teeth of the magnetic pole are attracted to generate rotational force, and when the rotor pole teeth reach the position where they are aligned with the pole teeth of the stator, the rotational force is lost. Stop.

Assuming now that the windings 3-1 and 3-5 are energized in FIG. 2 (b), the stator magnetic poles 2-1 and 2-5 are magnetized,
Assuming that the pole teeth of the rotor magnetic poles 7 and 8 are aligned with respect to the pole teeth of the respective stator magnetic poles, the stator magnetic poles 2-2 and 2-5 adjacent to the stator magnetic poles 2-1 and 2-5, respectively. 2-8 and 2
-4 and 2-6, and furthermore, the pole teeth provided at the tip of each of 2-3 and 2-7 at a right angle position are not aligned with the pole teeth of the rotor magnetic pole at the opposing positions. The angle is shifted by a certain theoretical value.

That is, the pole teeth provided on the stator magnetic poles 2-2 and 2-6 are rotated clockwise by an angle of 1/4 of the pitch of the pole teeth of the rotor magnetic poles with respect to the pole teeth of the rotor magnetic poles facing each other. The pole teeth provided on the stator magnetic poles 2-3 and 2-7 at the shifted positions are as follows.
Positions shifted clockwise by 2/4 of the pitch of the pole teeth of the rotor magnetic poles with respect to the pole teeth of the rotor magnetic poles facing each other, and pole teeth provided on the stator magnetic poles 2-4 and 2-8 Are disposed so as to be clockwise shifted by 3/4 of the pitch of the pole teeth of the rotor magnetic poles with respect to the pole teeth of the rotor magnetic poles facing each other. Winding 3 from position
When the currents of -1 and 3-5 are stopped and the windings 3-2 and 3-6 are energized, the stator rotates rightward by 1/4 of the pole tooth pitch of the rotor magnetic poles and stops.

This rotation angle is referred to as the step angle of the stepping motor, and is a numerical value unique to / 4 of the pole tooth pitch of the rotor magnetic pole, and indicates the resolution of the stepping motor.

To rotate further to the right, the right adjacent stator pole 2-
It is sufficient to energize the windings 3-3 and 3-7 to magnetize 9 and 2-7. Similarly, to rotate to the left, it is sufficient to energize the winding of the stator magnetic pole adjacent to the left of the currently magnetized stator magnetic pole. Since the direction of rotation can be controlled by the right or left side of the winding, the angle, speed,
Since the direction can be controlled, it has been used very often as a control motor.

In order to reduce the resolution, which is one of the performances of the stepping motor, it is common practice to increase the number of stator magnetic poles and the number of pole teeth provided on the rotor magnetic poles, and FIG. , (B), for example, rotor magnetic poles 7 and 8
By providing 50 pole teeth at each of the above, and providing 5 pole teeth at the tips of the 8 stator poles, the one-step angle is 1.
An 8 degree stepping motor is realized, and the step angle can be 0.9 degree by providing 16 stator poles and 100 rotor teeth for each rotor pole.

However, in response to the demand for further reducing the resolution of the stepping motor as described above, the resolution can be infinitely reduced by increasing the number of pole teeth provided on the rotor in principle. However, there is a limit on the number of pole teeth for the same size, and therefore, there is a limitation on work and it is impossible to increase the number of pole teeth.

One means for solving such a problem is disclosed in
No. 277360 and U.S. Pat. No. 4,675,564 are known.

In this known means, the number of magnetic poles of the stator is set to 16 with the same dimensions as the conventional product, and the number of pole teeth Z provided on the rotor magnetic poles is Z =
When 16 m ± 4, the arrangement pitch between the magnetic poles of the stator is α = 360 (1/1) between the corresponding magnetic poles of the adjacent magnetic poles.
14 with 6 ± 1 / 8Z degrees and β = 360 (1/16 ± (1-1 / 8) /
Z) are arranged in such a way that they are combined with each other,
A step angle of 0.45 degrees is realized with 100 rotor teeth.

In the above example, a stator with 16 magnetic poles and a rotor with 100 pole teeth achieved a step angle of 0.45 degrees,
On the other hand, since the magnetic pole arrangement of the stator is no longer equal pitch,
When stacking stator cores, it is not possible to perform rotary stacking to reduce punching errors of the iron cores.

That is, the stator cores punched out one by one cannot be stacked at the same position without being stacked at the same position, and the stator cores cannot be stacked so as to cancel the shape error at the time of punching. For this reason, there remains a problem that the accuracy of the stop position of the rotor cannot be increased.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a permanent magnet type stepping motor having a small step angle, which can solve the above-mentioned problems in the prior art and can be rotated and stacked at the time of laminating the stator cores and is easy to machine.

[Means for solving the problem]

In the permanent magnet type stepping motor of the present invention, 16
The stator poles are arranged at equal intervals at a pitch of 22.5 degrees, a plurality of pole teeth are provided at the tip of each stator pole at the same pitch as the pole poles of the rotor pole, and the pole teeth of the rotor pole are The number of teeth Z of Z =
16m ± 2 (m = 1,2,3 ... positive integer), and the rotor magnetic poles facing the pole teeth of the adjacent stator magnetic poles 2-1 to 2-16 The windings 3-1, 3-2, 3-3, 3-3, 3-2, 3-3, 3-2, 3-3, 3-2, 3-3 are arranged so that the angle of deviation from the teeth is an integral multiple of 1/8 of the pitch of the rotor magnetic poles −3, 3-4 are set as reference windings, and four windings each having a branch number of 4 are sequentially added to each reference winding, and a winding having a branch number of 4 is set as 12 windings.
The larger winding is connected so as to have the opposite polarity to the other windings to form a single-phase winding, thereby forming a four-phase winding.

(Operation)

In the permanent magnet type stepping motor of the present invention, the deviation angle between the position of the pole teeth of each of the adjacent stator magnetic poles 2-1 to 2-16 and the position of the pole teeth of the opposed rotor magnetic pole is determined by the pole of the rotor magnetic pole. It is an integral multiple of 1/8 of the tooth arrangement pitch, and the windings 3-1 to 3-16 wound around the respective stator magnetic poles are connected to the windings 3-1 and 3-3.
−2, 3-3, and 3-4 are set as reference windings, and four windings each having a larger branch number are sequentially added to each reference winding. The larger winding is connected so as to have the opposite polarity to the other windings to form a single-phase winding to form a four-phase winding. By sequentially energizing each phase,
The rotor magnetic pole is rotated by 1/8 of the arrangement pitch of the pole teeth, and the rotor magnetic pole is smaller than the conventional permanent magnet type stepping motor shown in FIGS. 2 (a) and 2 (b). Even if the number of pole teeth is 1/2, the same reference step angle can be obtained.

In addition, since the magnetic poles of the stator core are arranged at the same pitch, when laminating the cores, it is possible to reduce the punching error of the core by rotating and stacking, thereby obtaining a step motor with high step angle accuracy. I can do it.

〔Example〕

In the permanent magnet type stepping motor according to the present invention, 16 fixed individual magnetic poles 2-1 to 2-16 are equally distributed on the stator core 2 as shown in FIGS. 1 (a) and 1 (b). A plurality of pole teeth are arranged at the tip of each stator pole at the same pitch as the pole teeth of the rotating individual magnetic poles 7 and 8 facing each other with a gap therebetween. Is Z = 16m ± 2 (m = 1,2,3
... positive integer).

The relationship between the number of pole teeth Z of the rotor magnetic poles 7 and 8 and the step angle in the present invention is as shown in Table 1, but the value of m is calculated for convenience up to 12, and the value of the step angle is below the decimal point. Posted to the fourth place.

1 (a) to 1 (c) are side views of a permanent magnet type stepping motor embodying the present invention, and a development view showing a correlation between stator magnetic poles and pole teeth and rotor magnetic poles. 5 shows a half and a winding connection diagram, and shows an example in the case where m = 3 and +2 in the relationship between the number of teeth Z and the step angle shown in Table 1. FIG.

In this example, as shown in FIG. 1 (b), the stator magnetic poles 2-1 to 2-8 are arranged at equal intervals of 22.5 degrees, and the tip of each stator magnetic pole has a pole tooth 2-. 21 to 2-23 are provided at the same pitch as the arrangement pitch of the pole teeth of the rotor magnetic poles 7 and 8 facing each other via the gap.

In this example, the number Z of pole teeth arranged on the rotor magnetic poles 7 and 8 respectively.
Is set to m = 3 according to the relational expression of Z = 16 m ± 2, and the value of +2 is taken, so that Z = 50, and the arrangement pitch of the pole teeth of the rotor magnetic poles 7, 8 is 7.2 degrees.

The pitch between the pole tooth 2-21 provided at the tip of the stator magnetic pole 2-1 and the pole tooth 2-21 of the adjacent stator magnetic pole 2-2 is 22.5 degrees, and oppose each other via a gap between the pitches. The number of pole teeth of the rotor magnetic pole is three, and the pitch between the left end of the pole tooth 16-1 and the left end of 16-4 is 7.2 × 3 = 21.6 degrees.
-1 and the stator magnetic pole 2 adjacent to the pole teeth 2-21
The angle difference between the pole tooth 2-21 and the pitch 22.5 degrees provided at the tip of -2 is 22.5-21.6 = 0.9 degrees, which is 1/8 of the 7.2-degree pitch of the pole teeth of the rotor magnetic pole. Hit.

The deviation angle between the pole teeth of the stator magnetic pole and the pole teeth of the rotor magnetic pole increases in proportion to the branch number of the stator magnetic pole.
It returns at -9 and returns from 2-16 to 2-1.

Windings 3-1 to 3-16 are wound around the stator magnetic poles, respectively, and the windings are wound as shown in FIG. 1 (c).
2, 3-3, 3-4 are set as reference windings, and four windings having branch numbers larger by four than the branch numbers of the respective windings are sequentially provided on each reference winding, and the winding numbers having the branch numbers larger by four are successively provided. The winding and the winding with the 12th larger branch number are connected in series so as to have the opposite polarity to the other windings.

That is, in FIG. 1 (b), the windings 3-1, 3-5, 3-9, 3-1
3 are connected in series to form the A-phase, and the windings 3-2, 3-
6,3-10,3-14 are connected in series to form a B-phase,
The windings 3-3, 3-7, 3-11 and 3-15 are connected in series, and C-
And windings 3-4, 3-8, 3-12, 3-16 are connected in series to form a D-phase, and windings 3-5, 3-6, 3
−7,3−8 and 3−13,3−14,3−15,3−16 are respectively connected to have the opposite polarity to the other windings.

FIG. 1 (b) shows a state in which A → is applied to the fixed winding, in which the pole teeth of the stator magnetic pole 2-1 and the pole teeth of the rotor magnetic pole face each other and are aligned. And the stator poles 2-
The pole tooth 2 and the pole tooth of the rotor magnetic pole face each other with a deviation of 0.9 degrees.
The pole teeth of the stator pole 2-3 and the pole teeth of the rotor pole are 0.9 ×
2 = 1.8 degrees and facing each other. The deviation angle between the pole teeth of the other stator magnetic poles and the pole teeth of the rotor magnetic poles increases at an integral multiple of 0.9 degrees.

Next, the energization of A → is stopped, and the energization of B → energizes the pole teeth 2-21 to 2-23 of the stator magnetic pole 2-2 and the pole teeth 16 of the rotor magnetic pole.
-4 to 16-6 are sucked, and the rotor rotates right by 0.9 degrees and stops. Further, when the power supply to B → is stopped and the power supply to C → is applied, the rotor magnetic pole rotates 0.9 degrees to the right and stops.

As described above, the permanent magnet type stepping motor according to the present invention operates at a step angle of 0.9 degrees by sequentially energizing the four-phase windings.

In the above embodiment, the number Z of the pole teeth provided on the rotor magnetic pole is Z =
Although the case where m = 3 and +2 is described in the relational expression of 16m ± 2, all cases in Table 1 showing the relationship between the number Z of pole teeth and the step angle when the numerical value of m is changed are also performed. it can.

For example, under the conditions of m = 6 and +2, the number of pole teeth Z is 98 and the step angle is 0.4591 degrees, which is almost the same as that of the improved conventional example, and the magnetic poles of the stator are arranged at equal intervals. In addition, since the arrangement of the pole teeth is also symmetric, when stacking the iron core of the stator, so-called rotary stacking can be performed by moving the position of the magnetic pole and stacking, and the shape error generated when punching the iron core is As a result, the positioning accuracy of the pole teeth of the stator magnetic poles is increased, and the stopping position accuracy of the rotor is improved.

According to the results of a product having substantially the same dimensions, the error rate of the stop position accuracy was about 5% in the conventional product, but could be reduced to about 2% or less by the structure of the present invention.

〔The invention's effect〕

In the permanent magnet type stepping motor according to the present invention, since the stator magnetic poles are arranged symmetrically as described above, when laminating the stator cores, so-called rotary stacking can be performed, and an error generated when punching the iron cores is performed. Can be distributed over the entire circumference, the accuracy of the stop position of the rotor can be increased, and the error rate can be reduced to half or less of that of the conventional technology.

[Brief description of the drawings]

1 (a) is a side view of a permanent magnet type stepping motor according to the present invention, FIG. 1 (b) is a developed view showing a correlation between a stator and pole teeth of a rotor, and FIG. 1 (c). FIGS. 2A and 2B are a sectional view and a side view of a conventional permanent magnet type stepping motor. 1 ... stator housing, 2 ... stator iron core, 2-1 to
2-16: stator poles, 2-20 to 2-23, 7-10, 8-10, 1
6-1 to 16-7: pole teeth, 3: stator winding, 3-1 to
3-16: winding, 4: end bracket, 5: bearing, 6: rotor shaft, 7, 8: rotor magnetic pole, 9: permanent magnet.

Claims (1)

(57) [Claims] 1. A stator in which 16 stator magnetic poles are radially implanted in a stator yoke, a plurality of pole teeth are provided at the tip of each stator magnetic pole, and a winding is wound around each stator magnetic pole. A plurality of rotor magnetic poles which are opposed to the pole teeth of the stator magnetic pole via a gap, and whose outer periphery is provided with pole teeth at substantially the same pitch as the pole teeth, and which are axially separated from each other; In a permanent magnet type stepping motor having a rotor composed of a permanent magnet magnetized with N and S poles in the axial direction sandwiched between the stator magnetic poles, the 16 stator magnetic poles are arranged at an equal pitch, The windings wound around the stator magnetic poles are connected so as to form four-phase windings, and the number of teeth Z is Z = 16m ± 2 (where m = 1,2) A permanent magnet type stepping motor characterized in that pole teeth are provided so as to be a positive integer such as, 3,.