JPS62189966A - Stepping motor - Google Patents

Abstract

PURPOSE:To prevent internal and external teeth from being attracted by a permanent magnet even if the internal and external teeth become minute, by holding them with a non-magnetic plate. CONSTITUTION:As an internal tooth 5 and an external tooth 6 are held with a non-magnetic plate 3, they would not be attracted by a permanent magnet 1 even if the thickness of the internal and external teeth 5 and 6 is small and their rigidity become weak. On that account, the internal and external teeth 5 and 6 can be super-multipolarized and the mutual facing area increased by getting into each counterpart each other.

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to a step motor.

[Background technology]

An example of a proposed step motor that can be made flat and thin is shown in FIGS. 9 and 10. That is, this step motor has a rotor having a disk-shaped permanent magnet 50 formed such that a plurality of magnetic poles N and S (not shown) magnetized in the axial direction alternately become different magnetic poles in the circumferential direction. 51, internal teeth 52 arranged on both sides of the permanent magnet 50 in the axial direction and projecting outward radially, and external teeth 53 projecting inward from the outer circumferential side of the internal teeth 52. The permanent magnets 50 are opposed to each other in substantially the same plane so that the same magnetic poles N in the circumferential direction of the permanent magnets 50 are deviated from each other by π with respect to 1 electrical angle.
A pair of stators 5. which are mutually rubbed in the circumferential direction of π/2 of the electrical angle on both sides of the stator 5. ! , , 55, and excitation coils 56.5 disposed on mutually opposite sides of the stators 54.55 in the axial direction to excite each of the stators 54.55.
7. 58.59 is each stator 54.55
It is a housing that also serves as a yoke.

In this way, the internal teeth 52 and external teeth 53 of the stators 54 and 55 face each other in the radial direction in substantially the same plane, so that the step motor can be made flat and thin.

By the way, the internal teeth 52 and external teeth 5 of this step motor
3 into each other to increase the opposing area or increase the number of poles to achieve a super multi-pole structure, the internal teeth 52 and external teeth 53 will be finely machined, so it is necessary to reduce the plate thickness. be. However, if the plate thickness is made thinner, the rigidity of the inner teeth 52 and outer teeth 53 becomes weaker.
There was a drawback that the permanent magnet 50 of the rotor 51 attracted the magnet.

[Purpose of the invention]

An object of the present invention is to provide a step motor that can prevent internal teeth and external teeth from being attracted to a permanent magnet even if they become minute.

[Disclosure of the invention]

The step motor of the present invention includes a yoke having a disk-shaped permanent magnet formed such that a plurality of magnetic poles magnetized in the axial direction alternately become different magnetic poles in the circumferential direction; The inner teeth arranged on both sides of the permanent magnet and protruding outward radially, and the outer teeth protruding inward from the outer periphery of the inner teeth are mutually connected with the distance between the same magnetic poles in the circumferential direction of the permanent magnet as one electrical angle. a pair of stators held by a non-magnetic plate so as to face each other in the same plane with a deviation of π, and which are mutually offset in the circumferential direction of π/2 of the electrical angle on both sides of the permanent magnet; It is equipped with an excitation coil that excites each of the two.

According to the configuration of the present invention, since the internal teeth and external teeth are held by the non-magnetic plate, even if the plate thickness of the internal teeth and external teeth becomes small and the rigidity becomes weak, they will not be attracted to the permanent magnet. Therefore, it becomes possible to increase the opposing area and achieve ultra-multipolarization.

Embodiment An embodiment of the present invention will be described with reference to FIGS. 1 to 7. In other words, this step motor includes a rotor 4 having a disk-shaped permanent magnet 1 formed such that a plurality of magnetic poles N and S magnetized in the axial direction alternately become different magnetic poles in the circumferential direction; Internal teeth 5 arranged on both sides of the permanent magnet 1 in the axial direction and projecting outward radially, and external teeth 6 projecting inward from the outer circumferential side of the internal teeth 5 form the permanent magnet 1. The same magnetic poles in the circumferential direction are held on the non-magnetic plate 3 so as to face each other on the same plane with a deviation of π from each other, and the distance between the same magnetic poles in the circumferential direction is π/of the electrical angle. A pair of stators 7.8 shifted in two circumferential directions;
Excitation coils 9 and 1o are provided to excite each of these stators 7.8.

The rotor 4 includes a rotating shaft 11, a bushing 12 attached to the rotating shaft 11, and a permanent magnet 1 attached to the bushing 12.

As shown in FIGS. 4 and 5, the permanent magnet 1 is formed at equal intervals so that a plurality of magnetic poles N and S magnetized in the axial direction alternately become different magnetic poles in the circumferential direction, and the same magnetic poles in the circumferential direction Both sides of the permanent magnet 1 in the axial direction are shifted by an electrical angle of π, assuming that the distance N is 1 electrical angle, that is, 2π, and therefore different magnetic poles appear on both sides of the permanent magnet 1 in the axial direction.

The stator 7.8, as shown in FIGS. 2 and 3,
Each consists of an inner tooth 5, an outer tooth 6, and a non-magnetic plate 3. The inner tooth 5 and the outer tooth 6 are integrally formed by punching or the like from the same magnetic thin plate. ring 14
The outer teeth 6 are supported by the outer ring 15 and the inner teeth 5
and the external teeth 6 are connected by connecting portions 13 at a plurality of locations, that is, four locations in the embodiment. And the outer diameter is outer ring 15
Internal teeth 5 and external teeth 6 are mounted on a non-magnetic plate 3 having the same diameter as the disk.
is fixed with adhesive. The non-magnetic plate 3 and the internal teeth 5 and external teeth 6 are overlapped and bonded together, but the internal teeth 5 and external teeth 6 may also be formed on the non-magnetic plate 3 by etching. The inner teeth 5 and the outer teeth 6 are formed at equal intervals equal to the number of magnetic poles N appearing in the circumferential direction of the permanent magnet 1, respectively. A pair of positioning protrusions 16 are formed on the periphery of the outer ring 15.

The housings 17 and 1.8 also serve as yokes, and each has an inner cylinder part 19 and an outer cylinder part 20, and each has a bearing 21 at the center.
1 is bearing. Circumferential grooves 22 and 23 are formed on the outer circumferential side of the tip of the inner cylindrical portion 19 and the inner periphery of the tip of the outer cylindrical portion 20, respectively.
The non-magnetic plate 3 of each stator 7.8 is locked, and the positioning protrusion 16 is engaged with a pair of positioning notches (not shown) formed at the tip of the outer cylindrical portion 20, thereby locking the non-magnetic plate 3 of each stator 7.8. It regulates rotation. A pair of housings 1
The stators 7.8 of 7.18 are joined together so that they face each other, but at this time, the stators 7.8 of the stakes 7.8 are connected so that the internal teeth 5 and external teeth 6 are shifted by an electrical angle of π/2 in the circumferential direction. do. Also, assemble the permanent magnet 1 so that it is located between the pair of stators 7 and 8. The axial gear between the permanent magnet 1 and the internal teeth 5 and external teeth 6 is set smaller than the radial gear between the internal teeth 5 and external teeth 6 to reduce leakage magnetic flux.

The excitation coil 9.10 is wound around a coil frame 24 made of an insulator, and this coil frame 24 is connected to the housing 17.
It is housed between the inner cylinder part 19 and the outer cylinder part 20 of 18.

This step motor is operated by an exciting coil 9 under control specified by a pulse train as shown in FIG. IO has mutual phase π
An applied voltage shifted by /2 is supplied.

Furthermore, by excitation of the excitation coils 9 and 10, the internal teeth 5 and external teeth 6 of each stator 7.8 alternately receive magnetic poles N or S as shown in FIG. perform step movements.

According to this embodiment, the inner teeth 5 and the outer teeth 6 are formed on the non-magnetic plate 3.
Therefore, even if the thickness of the inner teeth 5 and the outer teeth 6 becomes smaller and their rigidity becomes weaker, they will not be attracted to the permanent magnet J. Therefore, it is possible to make the internal teeth 5 and the external teeth 6 extremely multipolar, and as shown in FIG. 8, the internal teeth 5 and the external teeth 6 can be inserted into each other to increase the area in which they face each other.

〔Effect of the invention〕

According to the step motor of this invention, the internal teeth and external teeth are held by a non-magnetic plate, so even if the plate thickness of the internal teeth and external teeth becomes smaller and their rigidity becomes weaker, they will not be attracted to the permanent magnet. . This has the effect of increasing the facing area and making it possible to have a large number of poles.

[Brief explanation of drawings]

Fig. 1 is a sectional view of an embodiment of the present invention, Fig. 2 is a partially omitted plan view of the stator, Fig. 3 is a reduced side view thereof, Fig. 4 is a plan view of the permanent magnets of the rotor, and Fig. 5. is a partial side view thereof, FIG. 6 is an explanatory diagram for explaining the stepping motion of the rotor, FIG. 7 is a waveform diagram of the voltage applied to the excitation coil, and FIG. 8 is a partial plan view of a modified example of internal teeth and external teeth. FIG. 9 is a schematic sectional view of the proposed example, and FIG. 10 is a partially omitted plan view of the stator. 1... Permanent magnet, 3... Non-magnetic plate, 4... Rotor, 5... Internal teeth, 6... External teeth, 7.8... Stator, 9, 10... Excitation Coil, N, S...Magnetic pole 1--Partly removed Zaro Figure 1 Figure 5 Figure 6 Procedural Dispute City Sho 1 ((Voluntary) May 10, 1985

Claims (1)

[Claims] A rotor having a disk-shaped permanent magnet formed such that a plurality of magnetic poles magnetized in the axial direction alternately become different magnetic poles in the circumferential direction, and a rotor that is arranged on both sides of the permanent magnet in the axial direction. The inner teeth protruding outward radially and the outer teeth protruding inward from the outer periphery of the inner teeth are on the same plane with a deviation of π from each other between the same magnetic poles in the circumferential direction of the permanent magnet. are held by a non-magnetic plate so as to face each other, and on both sides of the permanent magnet, the angle is π/2 of the electrical angle.
A step motor that includes a pair of stators that are offset in the circumferential direction and excitation coils that respectively excite these stators.