JPS60164375A - Magnetostrictive material - Google Patents

Abstract

PURPOSE:To increase the output of signals, to reduce loss of longitudinal elastic wave signals during propagation, and to augment mechanical strength by a method wherein the surface of a high-purity magnetostrictive material is coated with a chemical plate layer of the same material and then subjected to heat treatment. CONSTITUTION:On the surface of a high-purity magnetostrictive material A, a chemical plate layer is deposited by using a material B same as the material A except that it contains some P. The magnetostrictive material A may for example be electroformed Ni. The surface of the material A is thinly plated with an Ni layer B that is formed by a chemical process. Heat treatment follows that lasts for about 30min at about 650 deg.C. With the material being constituted as such, the pure Ni inside the material A is annealed to grow less hard while its electromechanical bondage coefficient grows higher. The surface layer B composed of Ni is hardened in the heat treatment because it contains some P, resulting in a good structural material excellent in its longitudinal wave propagating feature.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to magnetostrictive materials used in magnetostrictive potentiometers and the like.

[Prior art]

A magnetostrictive potentiometer that uses ultrasonic waves that propagate magnetostrictive lines was developed by Ideto Kokui, and the developed technology is disclosed in Japanese Patent Application No. 53-22281 and Japanese Patent Application No. 53-22282.
Yokogawa New Technology Report)'
79, P3 (1979), etc., and is already well known. Such a known Ni strain potentiometer is shown in FIG.

In FIG. 1, 10 is a magnetostrictive wire, 20 is a drive unit formed by a drive coil 21 for generating ultrasonic waves and a water-immersed magnet 22, and 30 is a detection unit consisting of a detection coil 31 and a permanent grinding stone 32. be. The detection section 30 is movable on the magnetostrictive wire 10 and receives an ultrasonic signal generated by the drive section 20 and propagated on the magnetostrictive wire 10. The displacement position of the detection section 30 can be determined by detecting the time taken for the ultrasonic signal generated by the drive section zO to reach the detection section 30. The position #C in FIG. 1 having such a configuration is suitable for application as a non-contact potentiometer, for example, to a position feedback element of a recording layer.

However, when the device shown in Figure 1 with such a configuration is used as a position feedback element of a recorder, etc., (1) it requires a longer configuration than the range to be measured, which takes up space within the device to be incorporated; rate becomes higher.

(2) Since the diameter and length of each coil differ depending on the device, each potentiometer must be redesigned when it is applied to a different model.

There are drawbacks such as.

Therefore, in order to solve these drawbacks, the applicant of the present application has also proposed a rotary magnetostrictive potentiometer using a magnetostrictive wire formed in a circular ring shape in Japanese Patent Application No. 58-186343. .

FIG. 2 is a block diagram of such a rotary magnetostrictive potentiometer. In FIG. 2, 4o is a magnetostrictive line, and this magnetostrictive line is formed in a substantially circular ring shape. 5o is magnetostrictive wire 4
This support part supports the magnetostrictive ta 40 and is formed approximately in an annular shape along the outer periphery of the magnetostrictive ta 40 with a certain gap therebetween. 01 to 64 are sugar portions that connect the magnetostrictive member a40 and the support portion 50, respectively. Distortion delay line 4
The supporting portion 50 and the sugar portions 61 to 64 are entirely formed by etching a plate of a metal such as Ni, which has a large magnetostrictive property. Since the sugar parts 61 to 64 are formed by etching in this way, these sugar parts are made extremely thin (0.1 mm in the example).
...0.2 mm). Support part 50
has its peripheral surface attached to a fixing member (not shown).

7o is a drive unit having a coil 71 for generating ultrasonic waves and a permanent magnet (not shown). This drive section is fixedly attached to one end 41 of the magnetostrictive wire 4o. 8o is a rotating shaft, 90 is a mounting member, and loo is a detection unit. Detection unit 10
= O is taken (= taken to the rotating shaft 8o via the J member 9o (-
I'm getting 1 digit. In the detection unit 100, 101.10
2 is a core, and 103 is a permanent magnet. A detection coil 104 for detecting ultrasonic waves is wound around the core 101 . The cores 101 and 102 are assembled in a U-shape with the permanent magnet 103 in between, thereby forming a detection head 414. The detection unit 100 having such a configuration is mounted on the rotation III 18o via the IJ member 90 so that the magnetostrictive wire 4o is inserted into the detection head with one side open. As a result, when the rotating shaft 8o is rotated, the detection unit 100 detects the magnetostrictive line 4 with this rotating shaft 8o as an axis.
Rotates in an arc along 0.

In the magnetostrictive potentiometer having such a configuration, when a pulse current is supplied to the ultrasonic generation coil 71 constituting the drive unit 7o, a local change in the magnetic field occurs in the magnetostrictive wire 40 in the coil 71, and the change is caused by the magnetostriction. Due to the effect, the inside of the magnetostrictive wire 40 is converted into a longitudinal elastic wave (ultrasonic wave) and detected by the detection unit 100.
propagate towards. - The detection head constituting the force detection unit 100 forms a magnetic path in which the magnetic flux generated in the permanent magnet 103 passes through the core 101 → magnetostrictive wire 40 → core 102 and returns to the permanent magnet 103 again. 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, a pulse voltage is generated in the detection coil 104 according to the displacement position of the detection unit 100. Occur.

Here, the ultrasonic generation coil 71 constituting the drive unit 70
The time from when a pulse current is applied to when a detection pulse signal is generated in the detection unit 100, that is, the direct wave from the coil 71 and the reflected wave reflected from the end face 42 of the magnetostrictive wire 40 and returned are detected. 119 times t required for the unit 100 to detect 1. By measuring t2, the displacement position of the detection unit 100, which is a movable part, can be detected. The following formula (1) is t1. t 2 Mountains and Flute Mountains F1 Na+, by increasing the number of trigrams to medium and small, the influence of the speed of sound is eliminated! It is possible to obtain a displacement position signal.

(t2.-t1)/(t2+tl)=d2
/ (dl-1-d2)・・・・・・・・・・・・
・・・・・・・・・・・・(1) Here, tl = dl
/ C t2 = (2d2 + dl) / C d1 = distance d2 from the moving part 70 to the detection fllll 100 - distance C between the end face 42 of the magnetostrictive wire 4o of the detection part 100 = 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 detection section 100, which is a movable section.

By the way, conventionally, @G! a10 or 4
For example, a rolled and strained sheet is formed into a predetermined shape by etching, or a pipe-shaped member is formed into a predetermined shape.

+1nL, 7 Yokasho 6 Positive R Equipment Distortion Oh S Note Heiching 1
1. If a material formed into a predetermined shape by a king or a pipe-like member formed into a predetermined shape is used as is, the propagation loss of the longitudinal acoustic wave signal will be reduced;
There are problems such as anisotropy in the propagation velocity and a small electro-mechanical coupling coefficient, resulting in a small output error signal. These drawbacks are that, although a large output signal can be obtained by removing anisotropy or increasing the electro-mechanical coupling coefficient by heat treatment, the propagation loss of the longitudinal acoustic wave signal also becomes large and the hardness is extremely high. This results in drawbacks such as lowering the temperature and making it difficult to handle.

[Purpose of the invention]

The present invention was made in order to improve these problems, and its purpose is to obtain a magnetostrictive material that can obtain a large output signal, has little propagation loss of longitudinal acoustic wave signals, and has excellent mechanical strength. It is something.

[Summary of the invention]

The present invention, which achieves these objects, is characterized in that a chemical plating layer made of the same material as the magnetostrictive material is deposited on the surface of a highly pure magnetostrictive material, and is also heat-treated.

〔Example〕

Examples of the present invention will be described in detail below.

FIG. 3 is a cross-sectional view showing one embodiment of the present invention, where A is a highly pure magnetostrictive material, and B is a chemical plating layer made of the same material as the magnetostrictive material A and containing phosphorus, which is adhered to the surface of the magnetostrictive material A. It is. Here, as the magnetostrictive material A, for example, electroformed Nj is used, and Ni is deposited on the surface thereof as a thin (about 20 μm) chemical plating layer B. Then, as the heat treatment, for example, about 650°
Heat at C for about 30 minutes. Note that these chemical plating and heat treatments are performed after the electroformed Ni sheet is etched into a predetermined shape.

With this configuration, the internal pure Ni material A is annealed to reduce its hardness and increase its electrical-mechanical coupling coefficient, and the Ni plating layer B on the surface contains phosphorus, so it cannot be heated by heat treatment. It has a high hardness and is good for plum afforestation and longitudinal wave propagation material. According to an experimental example, a magnetostrictive wire made by simply etching an electroformed Ni sheet into a predetermined shape has an output voltage of 80 mV and a logarithmic attenuation rate of 0.0.
012 (1/mm), but when only the heat treatment described in n11 is applied, the output voltage increases to 150 mV, but the logarithmic attenuation rate also increases to 0;006 (1/mm), and the chemical plating layer B When heat treatment is performed after depositing, the output voltage further increases to 205 mV and the logarithmic attenuation rate decreases to 0,000!5 (1/mm), making it possible to realize a magnetostrictive material with excellent properties by the present invention. was confirmed.

In addition, the reflective end n1 (4
By extending 2 to be longer than the circumference of the ring of the potentiometer, the effective rotation detection angle can be widened. In this case, the reflective end portion 42 may be formed to extend on the same plane as the circumference, or may be formed to extend so as to intersect with the circumferential direction.

Further, a detecting section for receiving an ultrasonic signal may be provided at one end of the magnetostrictive wire, and a driving section for generating an ultrasonic signal may be provided on the moving body.

Alternatively, a plurality of either the drive section or the detection section may be provided, and the rotation angle may be calculated from the difference in arrival time of the longitudinal acoustic waves to the detection section.

Furthermore, an electrostrictive element may be used to generate longitudinal elastic waves.

Further, the magnetostrictive material is not limited to Ni, and may be other magnetostrictive materials.

Further, in the above embodiment, an example was shown in which the magnetostrictive potentiometer was constructed using a magnetostrictive material, but the present invention is not limited to this, and can be used in various magnetostrictive devices.

〔Effect of the invention〕

As explained above, according to the present invention, a reasonable output signal can be obtained, there is little loss of transmission of the longitudinal acoustic wave signal, and the mechanical strength is also improved. 1 can be lucky.

[Brief explanation of drawings]

1 and 2 are configuration diagrams of a conventional magnetostrictive potentiometer, and FIG. 3 is a sectional view showing an embodiment of the present invention. 40...Magnetostrictive wire, 50...Support part, 61-64...
・Sugar section, 70... Drive section, 80... Rotating shaft, 90.
... Mounting member, 100... Detection section, A... Magnetostrictive material,
B... Ihigaku plating layer.

Claims (1)

[Claims] A magnetostrictive material characterized in that a chemical plating layer of the same material as the magnetostrictive material is applied to the surface of a highly pure magnetostrictive material and is also heat-treated.