JPH0667170B2 - Outer rotor type stepping motor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a stepping motor, and more particularly to an outer rotor type stepping motor in which a rotor is provided outside a stator.

[Prior Art] FIGS. 1 (a) and 1 (b) show a conventional stepping motor, in which a plurality of magnetic poles 1-2 to 1-9 are provided on an annular yoke 1-1 of a stator 1. Radially implanted toward the center, pole teeth 1-10 are formed at the tips of the magnetic poles, and stator windings 2-2 to 2-9 are wound around each magnetic pole.

Further, rotor poles 6-1 and 6-2 having pole teeth 6-10 on the outer circumference thereof are sandwiched with a permanent magnet 7 and integrally fixed to the rotor shaft 5 to form the rotor 6, and The child shaft 5 is supported by a bearing 4, and the rotor 6 is rotated while being arranged to face the stator 1 with a gap therebetween. In addition, 3 shows an end bracket.

In the conventional stepping motor shown in FIGS. 1 (a) and 1 (b), the pole teeth provided on each of the adjacent magnetic poles of the plurality of magnetic poles provided on the stator are 1/1 / the pitch of the rotor pole teeth. Stator winding 2 wound around each magnetic pole, which is arranged by shifting 4 pitches in sequence
By sequentially energizing the rotor 6, the rotor 6 rotates by 1/4 of the pitch of the pole teeth. Therefore, the rotation angle of the rotor 6 is proportional to the number of times the energized winding is switched, and the rotation angle is controlled. Since the device is simple, it is widely used in many control devices.
In order to improve the control quality by utilizing this feature, it is necessary to make the rotation angle of the stepping motor fine, and the rotation angle becomes finer as the number of pole teeth provided on the rotor increases.

However, in the stepping motor shown in FIG. 1, since the rotor is provided inside the stator, the outer diameter of the rotor must be smaller than the outer diameter of the stator.
If the number of pole teeth provided on the outer circumference of a rotor with a certain outer diameter is increased, the shape of pole teeth becomes smaller, and there is a limit to the number of pole teeth due to the shape of teeth that can be economically processed. In order to increase the number of pole teeth beyond that, it is necessary to increase the outer diameter of the rotor, and the outer diameter of the stator is inevitably increased in the conventional configuration, and a small rotation angle is obtained with a small stepping motor. There was a problem that I could not.

In order to solve this problem, an outer rotor type stepping motor in which a rotor is arranged outside a stator has been proposed as shown in FIG. By doing so, the diameter of the gap in which the pole teeth provided on the outer side of the stator and the pole teeth provided on the inner side of the rotor face each other can be increased, so that the number of pole teeth that can be provided on this gap is increased and It is possible to obtain a small angle of rotation without increasing.

However, in the outer rotor type stepping motor shown in FIG. 2, since the inside and outside of the stator and the rotor of the conventional structure are interchanged as they are, the diameter on the rotor side becomes large and therefore the heavy permanent magnet. Since the rotor core and the two rotor cores are provided, there is a problem that the inertial performance rate of the rotor increases and the response performance deteriorates.

[Object of the Invention]

An object of the present invention is to solve the problems of the conventional outer rotor type stepping motor and to obtain a stepping motor having good response performance.

[Outline of Invention]

The outer rotor type stepping motor of the present invention has a plurality of magnetic poles radially radially outwardly planted on the outer periphery of an annular yoke, and each of the above magnetic poles of a stator iron core having pole teeth at the tips of the magnetic poles. An outer rotor type stepping motor comprising a stator formed by winding respective windings, and a rotor provided on the outer periphery of the stator and having pole teeth opposed to the pole teeth via a gap, The stator iron core is formed by two annular yokes that sandwich a permanent magnet and are axially separated from each other, and an even number of magnetic poles that radially extend outward in the radial direction and are spaced apart from each other in the circumferential direction. , Each of the magnetic poles is axially bent at a position adjacent to the annular yoke, the odd-numbered one of the magnetic poles is connected to one of the annular yokes, and the even-numbered one of the magnetic poles is the annular shape. Connected to the other side of the yoke And wherein the door.

[Structure of Invention]

 Embodiments of the present invention will be described below with reference to the drawings.

In the present invention, as shown in FIGS. 3 (a) to 3 (c), in the outer rotor type stepping motor, the permanent magnet 7 is removed from the rotor 6 and provided on the stator side, and the rotor pole 6-1, 6-2
To reduce the inertial performance rate of the rotor 6 as well as two annular yokes 1-1 which axially separate the stator iron core with the permanent magnet 7 therebetween and the outer peripheral position of the permanent magnet 7. An even number of magnetic poles 8-1 radially arranged radially outward from the odd-numbered magnetic poles 8-1 sequentially arranged in the circumferential direction
And an even-numbered magnetic pole 8-2, and these magnetic poles 8-1 and 8-2 are bent in the axial direction by δ alternately in the opposite direction at positions adjacent to the annular yoke 1-1. The odd-numbered magnetic pole 8-1 is connected to one of the two annular yokes 1-1, and the even-numbered magnetic pole 8-2 is the other of the two annular yokes 1-1. So that the pole teeth of each magnetic pole of the stator iron core are arranged to face the pole teeth of the rotor pole of the rotor 6 via a gap.

The axial length of the magnetic poles 8-1 and 8-2 of the stator iron core, that is, the thickness is the axial length of the rotating pole integrated with the rotor,
That is, it is substantially the same as the thickness.

Since the outer rotor type stepping motor of the present invention has the above-described structure, the stator winding 2-2 wound around each magnetic pole is used.
The rotor 6 is rotated by an angle corresponding to 1/4 of the arrangement pitch of the pole teeth of the rotor 6 by sequentially energizing ~ 2-9.

〔The invention's effect〕

The present invention having the above-mentioned configuration has the following effects.

(1) Compared with the conventional outer rotor type stepping motor shown in FIG. 2, since the rotor does not have a permanent magnet, the axial length of the rotor pole can be shortened, and the weight can be reduced for rotation. The inertial ratio of the child is reduced and the response performance is improved.

(2) Since the axial length of the magnetic poles of the stator iron core is almost equal to the length of the rotor poles facing each other, and is shortened by the length of the permanent magnet, the amount of winding wound around this portion at the same ampere-turn is The efficiency is reduced.

[Brief description of drawings]

1 (a) and 1 (b) are a longitudinal sectional front view and a longitudinal side view of a conventional stepping motor, FIG. 2 is a longitudinal sectional front view of a conventional outer rotor type stepping motor, and FIG. 3 (a) is an outer rotor of the present invention. Side view of a vertical stepping motor, Fig. 3
(b) and (c) are cross-sectional views taken along line AA and BB of FIG. 3 (a),
4 (a) and 4 (b) are longitudinal sectional front views and side views of the magnetic poles and the stator yoke of one stator iron core, and FIGS. 5 (a) and 5 (b) are the other stator iron cores. 6A and 6B are longitudinal sectional front views of the magnetic poles and the stator yoke, and FIGS. 6A and 6B are longitudinal sectional front views showing a state in which the magnetic poles and the stator yokes of the one and the other stator iron cores are combined. FIG. 6 (c) is a side view thereof. 1 ...... Stator, 1-1 ...... Annular yoke, 1-2 to 1-9 ...... Magnetic pole, 1-10, 6-10 ...... Pole tooth, 2, 2-2 to 2-9 ...... Fixed Child winding, 3 ... End bracket, 4 ... Bearing, 5 ... Rotor shaft, 6 ... Rotor, 6-1, 6-2 ... Rotor pole, 7 ...
… Permanent magnets, 8-1, 8-2 …… Magnetic poles of the stator core.

Claims (4)

[Claims] 1. A plurality of magnetic poles are radially radially outwardly planted on the outer circumference of an annular yoke, and a winding is provided on each of the magnetic poles of a stator iron core having pole teeth at the tips of the magnetic poles. In the outer rotor type stepping motor comprising a stator formed by winding and a rotor provided on the outer periphery of the stator and having pole teeth opposed to the pole teeth through a gap, the stator iron The core is formed by two annular yokes that sandwich a permanent magnet and are axially separated from each other, and an even number of magnetic poles that radially extend outward in the radial direction and are separated from each other in the circumferential direction. Is bent in the axial direction at a position adjacent to the annular yoke, the odd-numbered ones of the magnetic poles are connected to one of the annular yokes, and the even-numbered ones are connected to the other of the annular yokes. Outer rotor type switch characterized by being connected Ppingumota. 2. The outer rotor type stepping motor according to claim 1, wherein the stator iron core is formed by laminating thin iron plates. 3. The outer rotor type stepping motor according to claim 1, wherein the stator iron core is formed by sintering powder of a magnetic material. 4. The iron core of the stator is formed by fixing powder of magnetic material with resin to form the stator iron core.
The outer rotor type stepping motor according to the item.