JPS60137079A - Nonlinear contactless potentiometer - Google Patents

Abstract

PURPOSE:To obtain the prescribed nonlinear function output having a fast responding speed by disposing two magnetoresistance elements of the same characteristics at a point symmetry with respect to the center of the rotation of a semicircular rotary magnetic field, and rotating said field. CONSTITUTION:Two linear square magnetoresistance elements 10, 11 of the same characteristics are disposed at a point symmetry with respect to the center 13 of rotation of a semicircular rotary magnetic field 12. The electrodes of one ends of the elements 10, 11 are connected with the different electrodes of a power source 14, and the electrodes of the other ends are connected with a common output terminal 15. In this structure, the interval between the elements 10 and 11 is represented by S and the rotating angle of the field 12 from the position of the broken line 16 is represented by theta and rotated, the output voltage exhibits a nonlinearity like a sine function as the magnetic field 12 rotates, and the nonlinearity degree increases as the interval S increases as shown by the line (a).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a non-linear non-contact potentiometer using two magnetoresistive elements.

Recently, there has been a growing trend to replace some of the functions of mechanical devices with electrical means. For example, this is the case when the function of converting the rotational motion of a machine into linear motion is performed electrically. However, although there are of course cases in which these conversions can be performed simply,
Non-linear elements are often added during conversion. Therefore, in such a case, a function compensation circuit for compensating for nonlinear elements is required in the servo control circuit that electrically controls the machine.

Such compensation methods include making use of the nonlinear characteristics of a transistor, which uses the fact that the current-voltage characteristics of a diode follow the 3/2 power law, and also using a sliding contact type potentiometer with many terminals. There are functions such as approximation.

However, the nonlinearity of transistors and diodes is originally 3/
Since it is a square law, there is a limit to the ability to obtain a curve approximation or a tangent curve approximation. In addition, since sliding potentiometers are directly coupled to and interlocked with mechanically moving shafts or plungers, they have drawbacks such as a shortened lifespan and hysteresis characteristics, a decrease in response speed, and poor linearity. I can't get anything satisfying.

The present invention provides a non-contact non-linear potentiometer that specifies the mutual distance between two linear magneto-electric conversion elements with respect to a magnetic field and obtains a predetermined non-linear function output.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In FIG. 1, the magnetoresistive elements 10 and 11 are made as rectangular linear magnetoresistive elements having the same shape and characteristics. The linear square type refers to one that is made square and linear as a whole even though the magnetically sensitive portion is made in a rectangular shape. Two magnetoresistive elements 1 (1, I) are distributed in a semicircular rotating magnetic field 120 in a point-symmetrical function with respect to the rotation center 13.The electrode at one end of the magnetoresistive element 'j'lo, 11 is connected to the power source. , for example, are connected to different poles of the DC power supply 14, and the electrodes at the other end are connected to a common output terminal 15.

In such a configuration, when the distance between the magnetoresistive elements 10 and 11 is set to 2S, and the magnetic field 12 is rotated from the position of the broken line 16 at a rotation angle of θ, the output voltage will change to the magnetic field 1 as shown in FIG.
It shows nonlinearity like a sine function according to 20 rotations,
As the distance S increases, the degree of non-linearity increases.

The output obtained in this way is a linearity compensation element when converting a mechanical rotation system of a pen recorder or similar device into a linear motion system, and a speed compensation element of an electronically controlled sewing machine using an IO circuit. Good linearity compensation can be achieved if used as

In the above embodiment, by changing the spacing between the two magnetoresistive elements, it is possible to obtain nonlinear function outputs with different characteristics, and even by changing the shape of the magnetic field acting on the magnetoresistive elements. , for example, by making the shape a 174 circle or a quadrilateral, non-linear outputs with different characteristics can be obtained.

FIG. 3 shows the schematic structure of the potentiometer.

A non-magnetic rotary shaft 18 supported by a bearing 17 is rotatably fixed to a cylindrical housing 16.

A permanent magnet 19 is fixed to the tip of the shaft 18,
Magnetoresistive element 22.2 placed at a position facing this
Apply a magnetic field to 3. Magnetoresistive elements 22 and 23 are connected to the substrate 20
The magnetic material yoke 2I is affixed to the surface of the magnetic material yoke 2I supported by the magnetic material yoke 2I.

The magnetic material yoke 2I is not limited to a flat plate shape, but as shown in FIG.
Since the magnetic field for 2.23 is concentrated and the acting magnetic flux density is increased, the output characteristics can be significantly improved.

In addition, instead of the magnetic material yoke 21, as shown in FIGS.
When a permanent magnet as shown in FIG. 1 is used, the magnetic field acting on the magnetoresistive elements 22 and 23 is sharply cut due to attraction or repulsion with the magnet 19, and the magnetic field strength is increased to promote the magnetoresistive effect. Especially FIG. 5(b).

This is noticeable in the U-shaped cross-section magnet 26.29 of tel.

As described above, according to the present invention, a predetermined nonlinear function output with a high response speed can be obtained by changing the interval between two linear magnetoresistive elements.

Therefore, the complicated operations that were conventionally performed using mechanical cams can be processed using more advanced electronic control technology, which opens the door to electrically controlling mechanical operations, resulting in more precise It is possible to perform high-speed mechanical operations.

In addition, since it is performed without contact, the potentiometer does not wear out and has a semi-permanent lifespan.

The potentiometer of the present invention can cause the rotary motion system of a sewing machine, pen recorder, Ben oscilloscope, NO machine tool, autorotator, etc. to perform a "C" operation in response to an electric signal, and can simplify the mechanical part of the machine.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of the inventive potentiometer, and FIG.
The figure shows the output characteristic diagram of FIG. 1, FIG. 3 is a schematic diagram of the configuration of the potentiometer of the present invention, and FIGS. 4 and 5 show examples of the magnetic material yoke according to the potentiometer of the present invention. In the figure, In, II, 22.23 are magnetoresistive elements, 12 is a magnetic field,! 3 is the rotation center, 15 is the output terminal, 19 is the magnet,
21, 24, 25, 26, 27, 28, and 29 are magnetic yokes. Patent applicant Denki Acoustic Co., Ltd.

Claims (1)

[Claims] 1. A voltage divider circuit configured by connecting a pair of linear magnetoresistive elements arranged separately in series, and a magnetic field that rotates about a rotation center located between the elements while acting on the elements. A non-linear device, characterized in that the pair of elements are arranged perpendicularly and parallel to a virtual line passing through the center of rotation, and a distance between the elements is specified to obtain a non-linear function output for each distance. Contactless potentiometer.