JPH0412636B2 - - Google Patents

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 propagating magnetostrictive lines was developed by the applicant of the present application, and the developed technology was disclosed in Japanese Patent Application No. 53-22281 (Japanese Unexamined Patent Publication No. 53-22281).
-115172 Publication), Japanese Patent Application No. 53-22282 (Japanese Patent Application No.
-115173), etc., and was published in Yokogawa New Technology Report '79, P3 (1979), etc., and is already well known. Such a known magnetostrictive potentiometer is shown in FIG.

In FIG. 1, 10 is a magnetostrictive wire, 20 is a drive unit composed of a drive coil 21 and a permanent magnet 22 for generating ultrasonic waves, and 30 is a detection coil 31 and a permanent magnet 3.
This is a detection unit composed of 2 and 2. 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 is determined by detecting the time taken for the ultrasonic signal generated by the drive section 20 to reach the detection section 30. The device of FIG. 1 having such a configuration is suitable for application as a non-contact potentiometer, for example, to a position feedback element of a recorder.

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 mounting part 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 proposed Japanese Patent Application No. 58-186343 (Japanese Unexamined Patent Publication No.
No. 60-78318) also proposed a rotating magnetostrictive potentiometer using a magnetostrictive wire wound approximately in an annular shape.

FIG. 2 is a block diagram of such a rotary magnetostrictive potentiometer. In FIG. 2, 40 is a magnetostrictive wire, and this magnetostrictive wire is wound approximately in an annular shape. Reference numeral 50 denotes a support portion that supports the magnetostrictive wire 40, and this support portion is wound approximately in an annular shape along the outer periphery of the magnetostrictive wire 40 at a constant gap. 61 to 64 are magnetostrictive wires 4, respectively.
0 and the support part 50. Distortion delay line 40
The supporting portion 50 and the connecting portions 61 to 64 are formed by etching a metal plate having a large magnetostrictive property, such as Ni. Since the connecting portions 61 to 64 are formed by etching in this manner, these connecting portions can be formed extremely thin (0.1 mm to 0.2 mm in the embodiment). The peripheral surface of the support portion 50 is attached to a fixing member (not shown). Reference numeral 70 denotes a drive unit having a coil 71 for generating ultrasonic waves and a permanent magnet (not shown). This driving section is connected to one end 4 of the magnetostrictive wire 40.
1 is fixedly attached. 80 is a rotating shaft, 90 is a mounting member, and 100 is a detection section. The detection unit 100 is attached to the rotating shaft 80 via a mounting member 90. In the detection unit 100, 1
01 and 102 are cores, respectively, 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 a permanent magnet 103 in between,
This constitutes a detection head. The detection unit 100 having such a configuration is attached to the rotating shaft 80 via the attachment member 90 so that the magnetostrictive wire 40 is inserted into the detection head with one side open. As a result, when the rotating shaft 80 is rotated, the detection unit 100 detects the magnetostrictive line 4 with this rotating shaft 80 as an axis.
Rotates in an arc along 0.

In the magnetostrictive potentiometer having such a configuration, the ultrasonic generation coil 7 constituting the drive unit 70
When a pulse current is supplied to the magnetostrictive wire 40 in the coil 71, a local change in the magnetic field occurs in the magnetostrictive wire 40, and this change is converted into a longitudinal elastic wave (ultrasonic wave) by the magnetostrictive effect, and the inside of the magnetostrictive wire 40 is transmitted to the detection section. It propagates towards 100. On the other hand, the detection head constituting the detection unit 100 forms a magnetic path in which the magnetic flux generated in the permanent magnet 103 returns to the permanent magnet 103 through the core 101 → magnetostrictive wire 40 → core 102. 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.
A pulse voltage is generated according to the displacement position of 00.

Here, after applying a pulse current to the ultrasonic generation coil 71 that constitutes the drive section 70, the detection section 10
0, that is, the time t1 required for the detection unit 100 to detect the direct wave from the coil 71 and the reflected wave reflected from the end face 42 of the magnetostrictive wire 40 and returned. By measuring t2, the displacement position of the detection section 100, which is a movable section, can be detected. Equation (1) below shows the calculation contents of t1 and t2, and by performing such calculation, it is possible to obtain a displacement position signal from which the influence of sound speed has been removed.

(t2-t1)/(t2+t1) = d2/(d1+d2)...(1) Here, t1=d1/c t2=(2d2+d1)/c d1=distance from the drive section 70 to the detection section 100 d2=detection Distance c between the section 100 and the end surface 42 of the magnetostrictive wire 40=sonic speed In other words, the ratio of the sum and difference of the delay times t1 and t2 becomes a signal representing the displacement position of the detecting section 100, which is a movable section.

Conventionally, such magnetostrictive wires 10 or 40 have been formed by, for example, etching a rolled magnetostrictive material sheet into a predetermined shape, or by forming a pipe-like member into a predetermined shape.

However, if such a rolled magnetostrictive sheet formed into a predetermined shape by etching or a pipe-shaped member formed into a predetermined shape is used as is, the propagation loss of longitudinal acoustic wave signals will be reduced. However, there are problems such as the propagation velocity being anisotropic and the electro-mechanical coupling coefficient being small, resulting in a small output 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.

[Objective of the Invention] The present invention was made in order to improve these problems, and it provides a magnetostrictive material that can obtain a magnitude output signal, has little propagation loss of longitudinal acoustic wave signals, and has excellent mechanical strength. It is intended to obtain.

[Summary of the invention]

The present invention, which achieves these objects, is composed of a magnetostrictive material made of a highly pure electroformed nickel sheet, and a nickel chemical plating layer containing phosphorus adhered to the surface of the magnetostrictive material, which can be subjected to high-temperature heat treatment. It is characterized by the fact that it has been applied.

〔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 Ni is used, and a thin (about 20 μm)
Ni is deposited as chemical plating layer B. Then, as the heat treatment, heating is performed at, for example, about 650° 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
When material A is annealed, its hardness decreases and its electro-mechanical coupling coefficient increases, and since the Ni plating layer B on the surface contains phosphorus, its hardness increases due to heat treatment, making it difficult for structural materials and the propagation of longitudinal waves. A good material can be obtained. 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 0.0012.
(1/mm), but when only the heat treatment described above is applied, the output voltage increases to 150 mV, but the logarithmic attenuation rate also increases to 0.006 (1/mm), and chemical plating layer B is applied. When post-heat treatment was performed, the output voltage further increased to 205 mV and the logarithmic attenuation rate decreased to 0.0005 (1/mm), confirming that the present invention can realize a magnetostrictive material with excellent properties.

Note that the reflective end 4 of the magnetostrictive wire 40 in FIG.
By forming 2 to extend 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 for the movable 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.

In addition, when generating longitudinal elastic waves,
An electrostrictive element may also be used.

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 described above, according to the present invention, it is possible to obtain a magnetostrictive material that can provide a magnitude output signal, has little propagation loss of longitudinal acoustic wave signals, and has excellent mechanical strength.

[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
... Connecting section, 70 ... Drive section, 80 ... Rotating shaft, 9
0... Mounting member, 100... Detection section, A... Magnetostrictive material, B... Chemical plating layer.

Claims (1)

[Claims] 1. Consisting of a magnetostrictive material made of a highly pure electroformed nickel sheet, and a nickel chemical plating layer containing phosphorus adhered to the surface of this magnetostrictive material, and subjected to high-temperature heat treatment. A magnetostrictive material characterized by