JPS62209301A - Positioner - Google Patents

Abstract

PURPOSE:To enhance performance and to enlarge a measuring range regardless of the presence of disturbance, by a method wherein a predetermined current is made to flow to an electromagnetic coil and the leak magnetic flux in a closed magnetic circuit different depending on the distance from the coil is measured by a magnetic detector and the position of said detector is detected. CONSTITUTION:A pair of the exciting coils 15 connected to a power source 9 in series are reverse in a winding direction to each other and the output of a magnetic detector 16 extracts the same frequency component as exciting frequency through a lock-in amplifier 20. When a current is supplied to a pair of the coils 15 using the positioner 11 thus constituted, leak magnetic fluxes decreasing as it is separated from the coils 15 and right to light reversed in direction from the center in the longitudinal direction flows into a closed magnetic circuit 12. The magnetic detector 16 moving through the closed magnetic circuit 12 detects the leak magnetic flux and the position of the magnetic detector 16 is known from detection information. This leak magnetic flux can be detected regardless of disturbance, and the enhancement of performance and the enlargement of a measuring range are realized.

Description

[Detailed Description of the Invention] [Summary] In a positioner that measures leakage magnetic flux in a closed magnetic circuit, the closed magnetic circuit is excited by an electromagnetic coil, the leakage magnetic flux in the closed magnetic circuit is measured by a magnetic detector, and the leakage magnetic flux in the closed magnetic circuit is measured by a magnetic detector. This is a high-performance positioner that detects the position and movement of the device.

[Industrial application field]

The present invention relates to a positioner (potentimeter), and more particularly to an improvement in a positioner configured to measure leakage magnetic flux in a closed magnetic circuit with a magnetic detector and detect the position of the detector.

[Conventional technology]

Fig. 6 is a perspective view showing the basic configuration of a conventional positioner that uses a permanent magnet and a magnetic detector, and Fig. 7 shows a conventional positioner that uses a closed magnetic circuit using a pair of permanent magnets and a magnetic detector. FIG. 3 is a side view showing the basic configuration.

In FIG. 6, a positioner 1 has a permanent magnet 2 and a magnetic detector 3 disposed facing each other in free space, one of which moves in the opposite direction. The magnetic detector 3 detects the strength of the magnetic field generated by the permanent magnet 2 and propagated in free space, and the facing distance l can be determined.

However, such a positioner 1 has a narrow measurement range, that is, a positioner 1 that combines a permanent magnet 2 with a magnetic force of 8000e and a magnetic detector 3 containing a magnetoresistive detection element made of a ferromagnetic metal thin film. In this case, the measurement range in which linear characteristics can be obtained is about 4 to 30 mm.

In FIG. 7, the positioner 4 moves in the length direction of the magnetic plates 6 between a pair of permanent magnets 5, a pair of magnetic plates 6 facing each other with the permanent magnets 5 at their ends, and the opposing magnetic plates 6. A pair of permanent magnets 5 are inserted so that their polarities face in opposite directions.

The positioner 4 configured in this way has a magnetic force of 800
When using a permanent magnet 5 of 0e, the measurement range is 20
It is 0 mm or more, and the measurement range can be expanded to about 7 times that of positioner 1.

[Problem that the invention seeks to solve]

As explained above, conventional positioners using permanent magnets and magnetic detectors have expanded the measurement range by constructing a closed magnetic circuit made up of permanent magnets and magnetic plates, but the measurement range is limited by the external magnetic field (disturbance). There was a problem that it was influenced by

Therefore, for example, even if a magnetic detector capable of detecting several mV is used, it is difficult to improve the performance of the positioner and expand the measurement range, as when using a positioner with a detection output of several tens of mV/mm. Ta.

Note that there is a linear scale that competes with the positioner of the present application. There are two types of linear scales: a magnetic scale that combines a magnetic storage medium and a magnetic detector, and a linear encoder that uses light. However, while the magnetic scale can easily detect the distance traveled by the magnetic detector, it stops Linear encoders have the drawback of not being able to detect the position of the magnetic sensing element, or of requiring cumbersome means to detect the stop position.Linear encoders require a plate with many fine grooves, making it difficult to manufacture the plate with high precision. It has the disadvantage of being.

[Means for solving problems]

FIG. 1 is a schematic side view showing an outline of a positioner according to a first embodiment of the present invention. A pair of electromagnetic coils 15 and a magnetic detector 16
and a power source 19 having a pair of electromagnetic coils 15 connected in series. The pair of electromagnetic coils 15 are wound so as to have opposite polarities.

According to FIG.
a magnetic detector 16 that moves in a direction parallel to the closed magnetic circuit 12;
A positioner comprising: an electromagnetic coil 15 that excites the coil; and a power source 19 that energizes the coil 15.
In addition, the power source 19 is an AC power source or a DC biased AC power source, and a large number of electrodes are provided on the inner surface of the magnetic plate 14 facing the magnetic detector 16 in a direction crossing the moving direction of the magnetic detector 16. The effect is enhanced by a positioner characterized by forming unevenness.

[Effect]

According to the above means, a predetermined current is passed through the electromagnetic coil, and a magnetic detector measures the leakage magnetic flux in the closed magnetic circuit, which varies depending on the distance from the coil, and detects the position of the detector. Detection is possible regardless of the presence or absence of disturbances, that is, measurements can be made without including disturbances, and the performance of bosisilana can be improved and the measurement range expanded.

〔Example〕

FIG. 2 is a side view showing the main structure of a positioner according to a first embodiment of the present invention, FIG. 3 is an output characteristic diagram of the positioner, and FIG. 4 is a second embodiment of the present invention. FIG. 5 is an enlarged side view of a part of the magnetic plate related to the positioner, and is an output characteristic diagram of the positioner equipped with the magnetic plate.

In FIG. 2, in which the same reference numerals are used for parts common to those in FIG. Excitation coil 15 and shaft 1 that can move left and right
7, a drive body 1B fixed to the middle part of the shaft 17, and a magnetic detector 16 fixed to one end (upper end) of the drive body 18.
, an AC power source 19 having a pair of coils 15 connected in series, and a lock-in amplifier 20.

The magnetic body 12 includes a pair of plate parts 4 facing each other in the vertical direction, the shaft 17 is movable in a direction parallel to the plate part 14, and the magnetic detector 16 is connected to the inner surface of the upper magnetic plate part 14 as appropriate. They face each other with a gap.

A pair of excitation coils 1 connected in series and connected to a power source 19
In No. 5, the winding direction of one winding direction is opposite to that of the other winding direction, and the output of the magnetic detector I6 is passed through a lock-in amplifier 20 or the like to extract the same frequency component as the excitation frequency (for example, 12 KHz).

In the positioner 11 configured in this manner, when the pair of coils 15 are energized, the amount of energy in the closed magnetic circuit 12 decreases as the distance from the coil 15 increases, and the magnetic field increases in the length direction (horizontal direction).
Reverse track numbers from the center to the right and left. Second leakage magnetic flux H
flows, and the magnetic detector 16 moving in the closed magnetic circuit 12 detects the leakage magnetic flux H, and the position of the magnetic detector 16 is known from the detected information.

In Fig. 3, the vertical axis is the output (mV) of the magnetic detector 16.
, the horizontal axis is the position y1 (mm) of the magnetic detector 16 with the center of the closed magnetic circuit 12 as the origin, and the output characteristic A of the magnetic detector 16 is approximately 1 mV except for the end near the coil 15.
/mm becomes a straight line.

In Fig. 4, a closed magnetic circuit board portion 2 made of a high magnetic permeability material is shown.
Reference numeral 1 corresponds to the above-mentioned plate part 14, and on its inner surface facing the magnetic detector 16, there are a number of protrusions 22 perpendicular to the moving direction of the magnetic detector 16, for example, a number of protrusions 22 with a height of 5 μm and a width of 20 μm. are formed at a pitch of 40 μm. Such protrusions 22 have the effect of increasing leakage of magnetic flux and increasing the output efficiency of the magnetic detector 16.

In FIG. 5, the vertical axis is the output (mV) of the magnetic detector 16.
, the horizontal axis is the position (mm) of the magnetic detector 16 with the origin at the center of the closed magnetic circuit including the plate portion 21, and the output characteristic B at that time has a shape in which a sine wave is superimposed on the output characteristic A shown by a dotted line. This corresponds to the amount by which the sine wave protrudes from characteristic A, and the output efficiency of the magnetic detector 16 can be increased.

Note that the protrusions 22 (irregularities) can be formed by a vapor deposition method or a photolithography technique using an aqueous solution of ferric chloride and nitric acid as an etching solution, and the cross-sectional shape of the protrusions 22 is not limited to the rectangular shape of the embodiment. A similar effect can be obtained even if the shape is triangular or trapezoidal.

Further, the protrusions 22 formed on the pair of opposing plate parts 21 are shifted, for example, so that the protrusions 22 of one magnetic body 21 and the recesses (middle between adjacent protrusions 22) of the other magnetic body 21 face each other, The measurement accuracy of a positioner equipped with a pair of magnetic detectors 16 facing each magnetic plate portion 22 is approximately twice as high as that of a positioner in which the opposing protrusions 22 directly face each other.

Further, in the above embodiment, the AC power supply or DC biased AC power supply 19 is used to obtain a leakage magnetic field that is detected without being affected by disturbance, and to extract the same frequency component as the excitation frequency from the output of the detector 16. Yes, AC power supply 1
If a DC power supply is used instead of the coil 15, the frequency component cannot be extracted from the output of the detector 16, but it has the effect of obtaining a detection output that is not affected by disturbances. However, it should be noted that by eliminating one of the coils 15 and connecting the ends of the magnetic plates 14 (or 21), it is possible to obtain a detection output unaffected by disturbances for applications with a narrow measurement range.

〔Effect of the invention〕

As explained above, according to the present invention, in order to detect the position of the magnetic detector without being affected by disturbance, the detection output can be made highly accurate, and thereby the measurement range can be expanded. Use power. By forming irregularities on the inner surface of the plate portion of the closed magnetic circuit, it was possible to enhance the effects of increasing precision and expanding the measurement range.

[Brief explanation of drawings]

1 is a schematic side view showing an outline of a positioner according to a first embodiment of the present invention; FIG. 2 is a side view showing the main structure of a positioner according to a first embodiment of the present invention; The figure is an output characteristic diagram of the positioner, FIG. 4 is an enlarged side view of a part of the magnetic plate related to the positioner according to the second embodiment of the present invention, and FIG. 5 is a positioner equipped with the RE fa magnetic plate. Figure 6 is a perspective view showing the basic configuration of a conventional positioner using a permanent magnet and a magnetic detector, Figure 7 is a closed magnetic circuit using a pair of permanent magnets and a magnetic detector. 1 is a side view showing the basic configuration of a conventional positioner. In the figure, 11 is a positioner, 112 is a closed magnetic circuit, 14.21 is a magnetic plate, 15 is an electromagnetic coil, 16 is a magnetic detector, 19
22 indicates a power source, and 22 indicates a protrusion (unevenness). Oka [August's horizontal 3F research method / da J
A's, 4th day (awakening ■ Showan 2 Figure 4 of the 7th society J anti-color positive βd-n this arm 1 figure ¥!-5 Lu

Claims (3)

[Claims] (1) A closed magnetic circuit (12) in which a pair of magnetic plates (14) face each other
), a magnetic detector (16) that moves between opposing magnetic plates (12) in a direction parallel to the magnetic plate (14), an electromagnetic coil (15) that excites the closed magnetic circuit (12), and A positioner characterized by comprising a power source (19) for energizing a coil (15). (2) The positioner according to claim 1, wherein the power source (19) is an AC power source or a biased AC power source. (3) The magnetic plate (
14) The positioner according to claim 1, wherein a large number of projections and depressions are formed on the inner surface of the magnetic detector in a direction perpendicular to the moving direction of the magnetic detector.