JPH0356057A - Apparatus for controlling rotation of movable element - Google Patents

Abstract

PURPOSE: To control all points on a matrix panel formed of a plurality of units using a small number of electrodes and control components by employing an arcuate inner face in the pole of an electromagnet and setting the open angle with respect to the rotary axis of each arc in the range of 70 deg.-110 deg.. CONSTITUTION: An electromagnet 1 has three poles 4, 4', 4" and a base part 3 wherein the poles are arranged arcuately on a circumference having a common center 8 at an open angle γ in the range of 70 deg.-110 deg., preferably at about 82 deg.. A permanent magnet 2 has two flat and parallel side faces 6, and two arcuate faces 7, 9 corresponding to north and south poles. A groove 5 in the permanent magnet 2 extends longitudinally along the faces 7, 9 on the center line thereof in parallel with the rotational axis 8. First groove 5 is located between one poles 5 and the other groove 5 is located in the space between other two poles.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for electromagnetically controlling the rotation of a movable element about its axis.

PRIOR ART It is a known technique to move a rotatable element containing a permanent magnet about its axis, for example as described in EP-A-87.104786.6 and EP-A-88, of which the applicant is the applicant. It is described in .100015.2. EP-A-87.10478
In 6.6, such a technique is used to rotate a cylinder containing a permanent magnet and stop it at a preselected position. This cylinder forms part of a device for displaying information, and its rotation is used to change the information appearing on the display.

EP-A-88. In IOOOl5.2, some preferred embodiments of electromagnets for controlling the rotation of this permanent magnet are shown. These electromagnets were primarily designed to move a cylinder containing a permanent magnet into six different positions by selectively actuating at least one of the electromagnet's magnetic poles. The end result of this is that a dieball magnetic field is formed where at least one of the nuclei is a multiball nucleus, ie the north or south pole (or both) is formed by at least two magnetic poles of the electromagnet.

The main drawback of this device is that misalignment of the permanent magnets can occur, ie, the permanent magnets can end up in a position that is only a few degrees off from the desired position. This misalignment significantly adversely affects the operation of the entire device. This is especially true when this device is used to display information.

Purpose of the Invention The present invention solves the problem of non-alignment of permanent magnets! The object of the present invention is to solve the above-mentioned problems by means of an unobtrusive device.

SUMMARY OF THE INVENTION According to the present invention, there is provided a device for controlling the rotation of a movable element symmetrical about an axis about the axis, the apparatus comprising a fixed electromagnet for controlling a permanent magnet built into the movable element; an arrangement in which the stationary electromagnet has three equally spaced magnetic poles each having at least one coil of one or more windings, wherein at least the inner surface of the magnetic poles of the electromagnet is shaped in the shape of a circular arc;
Further, there is provided a device characterized in that the opening angle of each of these circular arcs with respect to the rotational axis is about 70 degrees to about 110 degrees.

Further, according to the present invention, in a method for electromagnetically controlling the rotation of a movable element containing at least one permanent magnet about its axis, the electromagnet is actuated by simultaneously passing current through three coils. , this current has a strength weaker than the critical strength of the related hysteresis loop for each coil, and the sum of these currents has a strength exceeding the critical strength, and the current is applied to two of the coils. A method is provided, characterized in that a third coil is caused to flow in a first direction and a third coil is caused to flow in a second direction, which is opposite to the first direction.

Furthermore, the present invention also relates to a matrix panel formed using a plurality of the above-described devices.

In the drawings, similar or corresponding parts are designated by the same reference numerals. FIG. 1 is a cross-sectional view of a device formed by an electromagnet 1 and a permanent magnet 2. FIG. This electromagnet l has three magnetic poles 4.4', 4'' and a base 3. The magnetic poles 4.4', 4'' are in the form of arcs arranged on a circumference with a common center 8, The length of is the first
The opening angle indicated by α in the figure is about 70 degrees to about 110 degrees. In practice, this angular range has been determined experimentally to be particularly effective in avoiding permanent magnet misalignment, and the optimum angle is about 82 degrees.

This electromagnet can be used with any type of permanent magnet, the most accurate positioning of which is achieved when using a permanent magnet 2 of the type shown in FIG.

The permanent magnet 2 has two substantially parallel flat sides 6 and two arcuate surfaces 7.9 corresponding to the north and south poles. In the preferred embodiment, the aperture angle of 7.9 is similar to the aperture angle of the pole 4-4''.

The main feature of the permanent magnet 2 is that each side 7.9 is provided with a groove 5. This groove 5 extends longitudinally along the surfaces 7.9 and is located on the center line of these surfaces and parallel to the axis of rotation 8 of the permanent magnet 2. In this way the magnetic flux is transferred to the magnetic pole 4'
through two positions on the surface 7 bounded by the groove 5 of this surface 7 to the permanent magnet 2, and from the permanent magnet 2 two similar positions bounded by the groove 5 on the surface 9. via the magnetic poles 4'' and 4. The converse is also true.

In this way, when the device is correctly dimensioned and assembled in each selected position of the permanent magnet, the first groove 5 is located in the middle of one of the magnetic poles, and the other magnetic pole 5 is located between the other two magnetic poles. located in the middle of the space.

In order to further improve the direction control of the magnetic flux, the magnetic poles 4 −
4'' may be changed as shown in FIGS. 2 and 3.

In the modification shown in FIG. 2, the groove 11 is provided inside the magnetic pole 10. That is, it is provided on the side facing the permanent magnet.

In the modification shown in FIG. 3, the magnetic pole l2 has an end slot. That is, there is a slot or gap 13 at its upper end.

In either case, the groove 11 and the slot 13 are provided at the position where the permanent magnet pl5 stops (in front of the magnetic pole 4' in FIG. 1). A simple grooved pole and a pole with a slot at the end are both illustrated in the perspective view of FIG. However, it is clear that the magnetic poles of the electromagnets should be of the same shape in one embodiment. Generally, the most preferred type of pole is a grooved pole.

As shown in FIG. 4, each pole 4.4', 4'' is provided with a coil 14, 15.16. Each of these coils consists of a preselected number of turns of wire.

In order to activate the electromagnet, the first coil or coil 15 of the magnetic pole 4' must have a strength sufficient to energize this magnetic pole 4', but less than the critical strength of the associated hysteresis loop. A current having a certain magnitude is supplied in the first direction. The same current is applied to poles 4 and 4'' and to pole 4'
The current is supplied in a direction opposite to the direction in which the first current supplied to the current flows. In this way, when current is simultaneously applied to the magnetic poles 4.4' and 4'', the combined effect of these currents is to operate the electromagnet l.This creates a multi-ball core die-ball magnetic field.For example, the magnetic pole 4. ' is the north pole, while the south pole is formed by the magnetic poles 4 and 4''.

Thus, the number of electrodes required for each device is three. A matrix panel implemented by a plurality of such devices is schematically shown in circuitry in FIG. In this figure, the magnetic pole 4-4'' is shown much smaller than in FIG. 1 to simplify the drawing.

As mentioned above, each pole of the electromagnet has one coil per electrode, and each electrode connects to all poles in the same row, column, or diagonal. In FIG. 5, for example, all the magnetic poles 4' on the left column are connected by electrodes 18. Electrodes 20 connect all poles 4 of the bottom row
” is connected.

Moreover, the electrode 21 is connected to all the magnetic poles 4 located on the same diagonal line.
is connected to.

The total number of electrodes for the matrix according to the invention is thus greatly reduced compared to the case with known matrices, and such a matrix is therefore much simpler and easier to manufacture than any conventional matrix. . The device according to the invention also allows much more precise positioning of the elements containing the permanent magnets.

In order to control this element, it is necessary to power all three electrodes across the desired element as described above. For example, as shown in FIG.
When attempting to activate the electrode 18. for element A.
20' and 21 and electrodes 18', 20 and 21 for element B are fed. Other elements, such as element C or element D, are energized by only one or two of the electrodes connecting them (electrode 20 for element C and electrodes 18 and 20 for element B), thereby controlling the electromagnets involved. It does not reach a critical strength sufficient to do so. This makes it possible to control all points of the matrix with a small number of electrodes and a small number of control parts.

Although the present invention has been described above in detail with respect to the preferred embodiments illustrated in the accompanying drawings, the present invention is not limited to these specific embodiments, and many changes and modifications can be made without departing from the spirit of the invention. Of course it can be done.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of an electromagnet and a permanent magnet, Figure 2 is a cross-sectional view of the magnetic poles of an electromagnet with different shapes, and Figure 3 is a cross-sectional view of the magnetic poles of an electromagnet with different shapes.
4 is a side view of the electromagnet, and FIG. 5 is a schematic diagram of the matrix region formed by a plurality of devices. l...Electromagnet, 2...Permanent magnet, 3...Base, 4.4'
, 4"...Magnetic pole, 5...Groove, 6...Side surface, 79...Face,
8. Rotation axis, 10. Magnetic pole, i1. Groove, 12. Magnetic pole, 13. Slot, 14.15.16. Coil, 18 20 21. Electrode.

Claims (1)

[Scope of Claims] 1. A device for controlling the rotation of a movable element symmetrical about an axis about the axis, the fixed electromagnet (1) controlling a permanent magnet (2) built into the movable element. and the fixed electromagnet has at least one coil (14, 15) each consisting of one or more windings.
, 16) with three equally spaced magnetic poles (4, 4'
, 4''), wherein at least the inner surface of the magnetic pole of the electromagnet is formed into a circular arc shape, and the opening angle (α) of each arc with respect to the rotation axis is approximately 70 mm.
A device characterized in that the temperature is from 110 degrees to about 110 degrees. 2. The device according to claim 1, wherein the opening angle (α) of the circular arc is about 82 degrees. 3. The device according to claim 1, wherein the permanent magnet (2)
has a groove (5) along each of its two magnetic poles, and this groove (5) is parallel to the rotational axis (8) of the permanent magnet (2) in the middle of the magnetic pole faces (7, 9). A device characterized by being located at. 4. Device according to claim 3, in which the pole faces (7, 9) of the permanent magnet are in the form of circular arcs with a radius and an opening angle similar to those of the magnetic poles (4-4'') of the electromagnet. 5. A device according to claim 1, characterized in that each pole (10, 12) of said electromagnet has a groove (11), slot (13) or similar portion between said poles. permanent magnet(
2), which is disposed facing the permanent magnet (2) and parallel to the rotation axis (8) of the permanent magnet (2). 6. Device according to claim 1, characterized in that each pole (4-4", 10, 12) of the electromagnet (1) has a single coil consisting of one winding. 7. At least one In a method of electromagnetically controlling the rotation of a movable element containing a permanent magnet about its axis, the electromagnet (1) is activated by simultaneously passing current through three coils (14-16). This current has a strength lower than the critical strength of the related hysteresis loop for each coil, and the sum of these currents has a strength exceeding the critical strength, and the current is applied to two of the coils. in a first direction and, for a third coil, in a second direction, which is opposite to the first direction. 9. A matrix panel formed by a plurality of devices configured to control rotation, wherein the plurality of devices are manufactured according to any one of claims 1 to 6.9. In the matrix panel, three oriented electrodes, vertical, horizontal and diagonal, connect the electromagnets of the movable elements in series, each electromagnet being powered by the three electrodes and energized to control the angular position. A matrix panel characterized by: