JPS6078318A - Magnetostriction potentiometer - Google Patents

Abstract

PURPOSE:To obtain a constitution where even a round magnetostriction wire can be supported without the influence upon signals by etching magnetostrictive materials to form the magnetostriction wire and a supporting part, which is connected to this wire through a connecting part, into one body. CONSTITUTION:When a pulse current is supplied to an ultrasonic wave generating coil 41 constituting a driving part 40, a local change of magnetic field is caused in a magnetostriction wire 10 in the coil 41. This change is converted to a longitudinal elastic wave, and it is propagated toward a detecting part 70 in the magnetostriction wire 10. Then, the permeance of the magnetic path is changed, and a pulse voltage is generated in a detecting coil 74 after a time corresponding to the displaced position of the detecting part 70. A time t1, which is required when the direct wave form the coil 41 is detected by the detecting part 70, and a time t2 which is required when the reflected wave which is reflected on an end face 12 of the magnetostriction wire 10 and is returned is detected by the detecting part 70 are measured to detect the displaced position of the detecting part 70. Since a ratio of the difference to the sum between delay times t1 and t2 is the signal indicating the displaced position of the detecting part 70 as a movable part, a potentiometer having an inexpensive constitution is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a magnetostrictive potentiometer that uses ultrasonic waves.

[Prior art]

8 A magnetostrictive potentiometer using sound waves was developed by the applicant of the present application, and the developed technology was disclosed in Japanese Patent Application No. 53-2.
No. 2281, Japanese Patent Application No. 53-22282, etc., and many applications have been filed, including the horizontal new technology report “79P3 (1979
), etc., and some of them are already known. Such a known magnetostrictive potentiometer is shown in FIG.

In FIG. 1, 10 is a magnetostrictive wire, 20 is a movable drive unit composed of an ultrasonic generation coil 21 and a permanent magnet 22, and 30 and 40 are detection coils 31 and 41 and permanent magnets 32 and 42, respectively. The detection unit is composed of: The detection units 30 and 40 are fixed to both fqi of the magnetostrictive wire 10,
The ultrasonic signal generated by the drive unit 20 and propagated through the magnetostrictive wire 10 is received. The displacement position of the drive unit 20 is determined by detecting the difference in time until the ultrasonic signals reach the detection units 30 and 40. The device shown in FIG. 1 having such a configuration is suitable for use as a non-contact potentiometer, for example, as a position return element for a recording needle.

When the magnetostrictive wire 10 used in the magnetostrictive potentiometer having such a configuration is attached to a fixed member, if the magnetostrictive wire 10 is supported at other than both ends, the output will be attenuated and an error will occur. Therefore, in the potentiometer shown in FIG. 1, the magnetostrictive wire 10 is supported by detecting sections 30 and 40 fixed at both ends thereof. On the other hand, as the magnetostrictive wire 10, a thin material such as a thin pipe or a thin ribbon is more suitable than a thick material because the influence of eddy current IM loss or propagation attenuation is smaller. However, the above-mentioned both-end support method cannot support magnetostrictive wires that are thin and have extremely weak strength, and furthermore, there are problems such as the inability to support magnetostrictive wires having shapes other than round, equilinear lines.

[Object of the present invention]

The present invention has been made in order to improve these problems, and is capable of supporting magnetostrictive wires that are thin and have shapes other than straight lines, such as round magnetostrictive wires, without affecting the signal. The object of the present invention is to obtain a magnetostrictive potentiometer with a simple overall configuration that can be used. Examples of the present invention will be described in detail below.

〔Example〕

FIG. 2 is a +16 diagram of an embodiment of the magnetostrictive potentiometer according to the present invention. In Figure 2, 10 is a magnetostrictive line,
This magnetostrictive wire has a round shape. Reference numeral 20 denotes a support part that supports the magnetostrictive wire w10, and this support part is formed in a shape of nine cubes along the outer periphery of the magnetostrictive wire 10 with a constant gap therebetween. 31 to 34 connect the magnetostrictive wire 10 and the support part 20, respectively! This is the J section. The strain retardation line 10, the support portion 20, and the connecting portions 31 to 34 are all formed by etching a metal plate having a large magnetostriction characteristic, such as Ni. Since the connections s31 to s34 are formed by etching in this way, according to the present invention, these connections are made extremely thin (0.1M...0 in the example).
．． 2mm) can be formed. The support portion 20 has its peripheral surface attached to a fixing member (not shown). 40 is a coil 41 for generating ultrasonic waves (and a permanent magnet 42 shown in FIG. 1).
). This drive unit is fixedly attached to one @ 11 of the magnetostrictive wire 10. 50 is the rotation axis, 6
0 is a mounting member, and 70 is a detection section. The detection unit 7o is attached to the rotating shaft 50 via a mounting member 60.

In the detection unit 70, 71 and 72 are cores, and 73 is a permanent magnet. A detection coil 74 for detecting ultrasonic waves is wound around the core 71 . Cores 71 and 72 are permanent magnets 7
3 is placed in a U-shape, thereby forming a detection head.

411 like this! A certain detection unit 70 is arranged so that the magnetostrictive wire 10 is inserted into the detection head whose negative side is open.
It is attached to the rotating shaft 50 via a J-shaped member 60.

When the rotating shaft 50 is rotated, the detecting section 70 rotates in an arc shape along the magnetostrictive line 1o about this rotating shaft.

In a magnetostrictive potentiometer with such a configuration, when a pulse current of g+ is supplied to the ultrasonic generation coil 41 constituting the drive section 40, a local change in the magnetic field occurs at 1° of the magnetostrictive wire in the coil 41, and the change occurs. is converted into a longitudinal elastic wave (ultrasonic wave) by the magnetostrictive effect and propagates within the magnetostrictive wire 10 toward the detection unit 70. On the other hand, in the detection head constituting the detection unit 70, the magnetic flux generated by the permanent magnet 73 is transferred from the core 71 to
A magnetic path from the magnetostrictive wire 1o to the core 72 and back to the permanent magnet 73 is formed.

When a magnetostrictive signal enters such a magnetic path, the permeance of the magnetic path changes due to the inverse magnetostrictive effect, causing a change in magnetic flux, and as a result, the detection coil 74 receives a signal after a time corresponding to the displacement position of the detection section 7°. A pulse voltage is generated.

Here, the ultrasonic generation coil 41 that constitutes the drive unit 40
The time from when a pulse current is applied to when a detection pulse signal is generated at the detection unit 70 is such that the direct wave from the coil 41 and the reflected wave reflected from the end face 12 of the magnetostrictive wire 10 are detected by the detection unit. Time required for detection of 70 t 1. t
By measuring 2, it is possible to detect the displacement position of the detection section 70, which is a movable section.

The following formula (1) is t1. This shows the calculation contents of t2. By performing such calculation, it is possible to obtain a displacement position signal from which influences such as changes in humidity on the speed of sound are removed.

(t2-tl)/(t2+tl) =d2/(dl+d2)・・・・・・・・・・・・
・・・・・・・・・・・・(1) Here, tl=dl/
C t2 = a27 c dl = distance d2 between the drive unit 40 and the detection unit 70 - distance C between the detection unit 70 and the end face 12 of the magnetostrictive wire 10 - speed of sound, that is, delay time t1. The ratio of the sum and difference of t2 becomes a signal representing the displacement position of the detecting section 7o, which is a movable section.

In the magnetostrictive potentiometer according to the present invention having such a configuration, the connecting portions 31 to 34 are formed integrally with the magnetostrictive wire 10 and the support portion 20 by etching, so that the connecting portions 31 to 34 are formed in the same manner as in the embodiment. It can be configured extremely thinly. As a result, according to the present invention, it is possible to obtain a magnetostrictive potentiometer having a support portion 20 that supports the magnetostrictive wire 10, which has a weak strength inside the womb, with almost no effect on the propagating longitudinal elastic waves. Further, according to the present invention, even a round magnetostrictive wire 10 can be supported, and since the magnetostrictive wire 10 and the support part 20 are formed by integral molding, the structure is simple, and moreover, the support part 20 is used. As a result, it is possible to obtain a magnetostrictive potentiometer that is easy to attach to the device and has an inexpensive structure.

(Other Examples) Although Fig. 2 shows an example of a magnetostrictive potentiometer in which the magnetostrictive wire is made into a round shape, Fig. 3 is a configuration diagram of an example of a linear magnetostrictive potentiometer in which the magnetostrictive wire is made into a linear shape. be. In FIG. 3, 10 is a YJ cotton wire magnetostrictive wire, 20 is a support part, 31...34 are connecting parts, 40 is a drive part attached to the end 11 of the magnetostrictive wire 10, and 70 is a displaceable detector. In the potentiometer of FIG. 3 having such a configuration, a linear magnetostrictive potentiometer having the same effect as that of FIG. 2 can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional magnetostrictive potentiometer, and FIGS. 2 and 3 are block diagrams showing embodiments of the magnetostrictive potentiometer according to the present invention. 10...m strain line, 20...support part, 3
1-34... Connecting part, 40... Drive part,
70...detection section.

Claims (1)

[Claims] A magnetostrictive potentiometer characterized in that a magnetostrictive wire and a support part to which a II recording magnetostrictive wire is connected via a connecting part are formed by integrally molding a magnetostrictive material by etching.