JPS6041476B2 - Contactless magnetic potentiometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a contactless magnetic potentiometer using a Hall element.

Various magnetic potentiometers using Hall elements have been proposed in the past. For example, the Hall element is rearranged near the periphery of a circular magnet magnetized in the diametrical direction, and the Hall voltage is determined by changes in magnetic flux caused by the rotation of the circular magnet. Or, a Hall element is arranged opposite to the axial surface of a circular magnet magnetized with two poles in the axial direction of the rotating shaft,
Some devices are known in which hole fin pressure is obtained by changing the magnetic flux when the permanent magnet is rotated.

In such a magnetic potentiometer, in order to obtain an output voltage waveform as, for example, a sine wave, the permanent magnet must be magnetized so that the magnetic flux density on the surface facing the Hall element changes to a sine wave. This magnetization method was difficult.

Furthermore, it is extremely difficult to obtain an arbitrary output voltage waveform such as a triangular wave. In view of the above-mentioned drawbacks, the present invention simplifies the structure and manufacturing method by arranging the magnet obliquely with respect to the Hall element, thereby creating a desired waveform without complicated attachment to the magnet. It is an object of the present invention to provide a contactless magnetic potentiometer that can obtain an output voltage of .

Hereinafter, embodiments using the present invention will be described in detail with reference to the drawings.

In FIGS. 1 to 3, reference numeral 1 designates a first yoke that is rotatable by transmitting angular displacement, and has a rotating shaft portion la formed on its upper surface, and mutually extending toward the center of the rotating shaft portion la on its lower surface. A slope lb is formed which is inclined in the opposite direction, and is rotatably attached to a case (not shown).

2 and 3 are rectangular permanent magnets magnetized in the thickness direction (vertical direction in FIG. 2), and the magnets 2 and 3 are magnetized so that the polarities are opposite to each other in the vertical direction in FIG. It is fixed to the cross section lb of the yoke.

A second yoke 4 is arranged perpendicular to the rotational axis of the first yoke 1, and is fixed to a frame (not shown) with a slight gap between the permanent magnets 2 and 3. .

Reference numeral 5 denotes a Hall element fixed to the surface of the second yoke 4 facing the permanent magnets 2 and 3.

Generally, a Hall element outputs a Hall voltage proportional to a change in applied magnetic flux density, and in the case of a magnetic field generating means that rotates in a plan view parallel to the Hall element,
In Fig. 1, the magnetic field is uniform in the left and right directions with respect to the horizontal line passing through the center of rotation of the first yoke 1, and the strength of the magnetic field increases linearly with opposite polarity in the up and down directions. It is expressed as a trigonometric function whose variable is the magnetic flux density applied to the Hall element with respect to the rotation angle of the generating means.

Therefore, in the present invention, the permanent magnets 2 and 3 are arranged obliquely relative to the Hall element so as to be close to the Hall element in a direction from the rotational axis of the first yoke 1. In addition, since the magnetic flux density B is generally expressed as a function of the quotient of the thickness of the permanent magnet and the length of the gap, the horizontal axis is the distance x in the vertical direction from the horizontal line passing through the center of rotation of the first yoke 1. As shown in Figure 4, which shows the magnetic flux density B as a vertical koji,
Its characteristics vary depending on the length of the gap and the roughness of the permanent magnets 2 and 3. For example, when the magnetic angle of the permanent magnets 2 and 3 is small, it becomes like the one-dot chain line in the same figure, and the head angle becomes smaller. If it is large, it will look like the two-dot chain line in the figure.

Therefore, in this embodiment, if the angles of the permanent magnets 2 and 3 are appropriately selected so as to have the characteristics shown by the solid line in the figure, the individual characteristics of the permanent magnets 2 and 3 are shown by the broken line branching from the solid line in the figure. However, the first part of permanent magnets 2 and 3
Because the parts near the center of rotation of yoke 1 are close together,
Due to the interaction of the magnetic flux flows from both permanent magnets 2 and 3, it is approximated by a straight line passing through the origin, as shown by the solid line in the figure, and the magnetic flux density B is approximately a straight line with respect to the distance from the rotation center of the first yoke. These permanent magnets can be changed to
, 3 are fixed to the first yoke, the waveform of the Hall voltage generated in the Hall element 5 can be output as an approximate sine wave.

Furthermore, as shown by the characteristics indicated by the two-dot chain line in Fig. 4, the permanent magnet 2
, 3, the output voltage of the Hall element 5 can be output as a triangular waveform, as is clear from the relationship between the rotation angle of the first yoke 1 and the characteristics shown in the figure. .

FIG. 5 shows a more specific embodiment using the present invention, and the configuration of the main parts is the same as the embodiment shown in FIGS. 1 to 3. In the figure, a first yoke and a second yoke 4, to which permanent magnets 2 and 3 are fixed at an oblique angle, are integrally attached with a non-magnetic material 6, and are attached to an upper case 7 so as to be able to rotate together. It is attached to the bearing section 8. Permanent magnets 2, 3
The Hall element 5 arranged in the gap between the second yoke 4 and the second yoke 4 is
It is fixed on a support stand 10 fixed to the lower case 9. In the embodiment shown in FIG. 5, the permanent magnets 2, 3 and the first,
Since the second yoke rotates integrally, there is an advantage that no eddy current flows through the second yoke.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but includes, for example,
The permanent magnet may have a semicircular or triangular shape, and two Hall elements may be arranged at positions separated by 90 degrees in electrical angle, and their output voltages may be calculated to achieve various compensation effects. You can also do this. As described above, the present invention has an extremely simple structure in which the rotating permanent magnets 2 and 3 are appropriately inclined and arranged relative to the Hall element 5, so that the output voltage waveform of the Hall element 5 can be changed to a sine wave or , it has the advantage that it can be set to a triangular waveform.

[Brief explanation of drawings]

FIG. 1 is a front view showing an embodiment using the present invention, FIG. 2 is a side view thereof, and FIG. 3 is a sectional view taken along line A--A of the embodiment in FIG. FIG. 4 is a characteristic diagram showing the distribution state of magnetic flux density, and FIG. 5 is a sectional view showing a main part of a more specific embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... First yoke, 2, 3... Permanent magnet, 4... Second yoke, 5... Hall element, 6...
...Nonmagnetic material, 7. ．． ．． Upper case, 8...bearing member,
9... Lower case, 10... Support stand. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. A first yoke having an axis through which angular displacement is transmitted;
a second yoke disposed opposite to the first yoke;
a Hall element installed parallel to the second yoke between the first and second yokes; and a Hall element magnetized in the thickness direction and inclined with respect to the Hall element. 1. A non-contact magnetic potentiometer comprising: a pair of permanent magnets fixed to a magnet; and bearing means rotatably supporting the first yoke or the first and second yokes. 2. a first yoke having an axis through which angular displacement is transmitted;
a second yoke disposed opposite to the first yoke;
a Hall element installed parallel to the second yoke between the first and second yokes; and a Hall element magnetized in the thickness direction and inclined with respect to the Hall element. and bearing means rotatably supporting the first yoke or the first and second yokes, the pair of permanent magnets being fixed to the first yoke. The first electrodes are tilted in opposite directions toward the center of rotation, and the polarities of the surfaces facing the Hall element are opposite to each other.
A non-contact magnetic potentiometer characterized by being fixed to a yoke.