JPS58262B2 - small motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small motor that can be used, for example, as an electromechanical converter in a quartz watch or the like.

In conventional small motors, stator magnetic poles that face each other with a rotor in between have generally had a symmetrical shape, regardless of whether the motor is a two-pole motor or a multi-polar motor.

In addition, small step motors for watches in particular have various drawbacks, such as the complicated structure and the strict requirement for relative positional accuracy of the stator magnetic poles with respect to the rotor.
This resulted in an increase in manufacturing costs.

A feature of the present invention is that one of the opposing stator magnetic poles is one pole and the other is two poles, and both stator magnetic poles are connected to the legs of the yoke that are connected to the ends of the U-shaped or U-shaped yoke. It is located in a straight line.

An object of the present invention is to provide a small motor for a timepiece that has an extremely simple configuration, is easy to manufacture and assemble, and operates stably.

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

In FIG. 1, 1 is a stator integrally formed of a magnetic material, and 2 is a permanent magnet rotor which is radially polarized with two poles and fixed to a rotor stem 2a.

The stator 1 is composed of a U-shaped yoke 3, and stator magnetic poles 45 which are connected to the tips of the two legs 3a of the yoke in a mutually opposing position.

6 is a bobbin around which an excitation coil 7 is wound, and is fitted into the leg piece 3a.

Next, the stator magnetic poles 4 and 5 will be explained in more detail.

The stator magnetic pole 4 extends straight and long from the leg piece 3a, and the surface facing the rotor 2 is a straight line.

On the other hand, the stator magnetic pole 5 has two magnetic pole parts 5a and 5b protruding from each other at a predetermined opening angle.

The magnetic pole portions 5a and 5b are formed in different shapes, and are also formed at asymmetrical positions with respect to the straight line 10 connecting the shortest position A of the stator magnetic pole 4 with respect to the rotor 2 and the axis O of the rotor 2. By making the air cap between the magnetic pole part 5a and the rotor 2 smaller than that between the magnetic pole part 5b and the rotor 2, the static stable stop line 11 that allows the rotor 2 to stably stop in the non-energized state and the movement of the stator in the energized state are achieved. It is designed to create a slip angle θ2 with the target magnetic center line 12.

Therefore, the operation of the motor according to the present invention will be explained with reference to FIGS. 2 to 7.

In the non-energized state, the rotor 2 has its N and S poles, the magnetic pole portions 5a and 5b of the stator magnetic pole 5, and the stator magnetic pole 4.
On the other hand, the rotor 2 is magnetically balanced and stopped in the state shown in the second figure, that is, with the N and S poles of the rotor 2 aligned with the statically stable stop line 11 rotated by θ1 counterclockwise from the center line 10.

Therefore, in the state shown in the second figure, suppose that the stator magnetic pole 4 is excited to the north pole and the stator magnetic pole 5 is excited to the south pole (this state is shown in FIG. 3).

), the clockwise rotational torque for the rotor 2 is:
The attractive force exerted by the stator magnetic pole 4 on the S pole of the rotor 2 and the repulsive force exerted on the N pole of the rotor 2, and the magnetic pole part 5b exerted on the S pole of the rotor 2.
The repulsive force exerted on the poles and the attractive force exerted on the north pole of the rotor 2 act, and the attractive force exerted by the magnetic pole portion 5a on the north pole of the rotor 2 acts as a counterclockwise rotational force on the rotor 2.

At this time, the clockwise rotational force exceeds the counterclockwise rotational force in FIG. 3, and the rotor 2 rotates clockwise by an angle θ2 from the state shown in FIG. The rotor 2 is magnetically balanced and stops at the position where the N and S poles of the rotor 2 coincide with the line 12, and does not rotate any further.

When the coil 7 is no longer energized, the rotor 2 returns to the second illustrated position.

Further, in the state shown in the second figure, when the stator magnetic pole 4 is excited to the S pole and the stator magnetic pole 5 is excited to the N pole, contrary to the above, (
This state is shown in FIG.

), the counterclockwise rotational force on the rotor 2 includes an attractive force between the stator magnetic pole 4 and the N pole of the rotor 2, a repulsive force between the stator magnetic pole 4 and the S pole of the rotor 2, and a magnetic pole portion 5b.
The attractive force between the S pole of the rotor 2 and the S pole of the rotor 2, and the repulsive force between the magnetic pole part 5b and the N pole of the rotor 2 act, respectively, and the clockwise rotational force on the rotor 2 is generated by the force between the magnetic pole part 5a and the N pole of the rotor 2.
A repulsive force acts between the N pole and the N pole.

At this time, the counterclockwise rotational force overcomes the clockwise rotational force, and the rotor 2 suddenly rotates counterclockwise from the state shown in the fifth figure to the state shown in the sixth figure, and becomes dynamic as shown in the seventh figure. The rotor 2 is magnetically balanced and stopped at a position where the N and S poles of the rotor 2 coincide with the magnetic center line 12.

Then, when the power is turned off, the rotor 2 further changes the angle θ2.
Rotate only counterclockwise and remain statically stable.

By supplying the excitation coil 7 with an inverted pulse signal as shown in Figure 8, the rotor 2 is always rotated counterclockwise once.
Rotates intermittently by 80 degrees.

Furthermore, the motor according to this embodiment has a characteristic stator shape that has not been seen before, in which the stator magnetic poles 4 extend straight and long from the leg pieces 3a, and the surface facing the rotor 2 is straight, as described above. For this purpose, Figure 2~
As shown in the operational diagram of FIG. 7, the magnetic flux between the rotor 2 and the stator magnetic poles 4 can move as the rotor 2 rotates.

That is, the magnetic flux between the rotor 2 and the stator magnetic poles 4 moves so as to connect the most efficient magnetic path.

The present invention described in detail above is based on a positional relationship in which the static stable stop line of the rotor and the dynamic magnetic center line of the stator are different, so that one of the opposing stator magnetic poles is made into two poles and the other is made into one pole. Therefore, self-starting of the rotor in a fixed direction is possible.

Furthermore, since the air gap between the rotor and the stator magnetic poles is large, stable operation is possible even if slight variations occur in the relative positional accuracy and magnetic flux density between the rotor and stator.

Furthermore, since the single-pole stator magnetic pole extends in a long straight line on the surface facing the rotor, the magnetic flux between the stator magnetic pole and the rotor moves to connect the most efficient magnetic path, thus improving drive efficiency. This reduces current consumption.

Furthermore, since the opposing gap between the stator magnetic poles is large, the stator can be easily attached even after the rotor is assembled first.

Furthermore, even if the stator poles are integrally connected to both ends of the U-shaped yoke and the stator is constructed as one component, the leg piece of the yoke and one of the stator magnetic poles connected to the leg piece of the yoke are straight, so the coil bobbin It can be installed by sliding it from the side, making manufacturing and assembly easy.

Further, since the leg piece into which the coil bobbin fits is narrow and has the same width as one stator magnetic pole, the volumetric efficiency of the coil, that is, the ratio of ampere turns to the volume of the coil is increased.

It has various other remarkable effects such as being able to be manufactured at low cost.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which FIG. 1 is a partially sectional plan view, FIGS. 2 to 7 are operation explanatory diagrams, and FIG. 8 is a waveform diagram of a drive signal. It is. 1... Stator, 2... Rotor, 3... Yoke,
4... Stator magnetic pole on the 1st pole side, 5... Stator magnetic pole on the 2nd pole side, 5a, 5b... Magnetic pole part, 7... Coil,
11... Static stable stop line of the rotor, 120-dynamic magnetic center line of the rotor.

Claims (1)

[Claims] 1. A small motor comprising a stator, a coil, and a rotor formed of permanent magnets and magnetized into two poles, wherein the stator comprises a yoke formed substantially in a U-shape and a yoke formed of a substantially U-shaped yoke. It consists of two stator magnetic poles that are integrally connected to the ends of both parallel leg pieces, and one of the stator magnetic poles is formed into one pole and the other is formed into two poles, and the stator magnetic pole on the one pole side is in a straight line with the leg piece to which it is connected, and the two magnetic pole parts of the stator magnetic pole on the two-pole side are in a straight line that passes through the center of the rotor and is orthogonal to the stator magnetic pole on the one-pole side. A small motor, characterized in that the coil is inserted into the leg piece, which is asymmetrically located on both sides of the leg piece and to which a stator magnetic pole on one pole side is connected. The two magnetic pole portions of the stator magnetic pole on the 22-pole side have different shapes.The two magnetic pole portions of the stator magnetic pole on the 32-pole side of the small motor according to claim 1 have different shapes. A small motor according to claim 1 or 2, in which the gaps are different.