JPH07316758A - Production of antenna element - Google Patents

Abstract

PURPOSE:To produce an antenna element for mobile object communication apparatus showing superelastic properties even at the transformation temp. or below by working a TiNiX (X=Cu, Cr, V, Mn and Zr) alloy at a specified working ratio and thereafter executing heat treatment at a specified temp. CONSTITUTION:A TiNiX alloy is worked at a working ratio of at least >=30%. The obtd. worked product such as a wire rod, pipe or the like is subjected to heat treatment at 280 to 300 deg.C for about 30min and is subjected to aging treatment. Thus, the wire or tubular antenna element for mobile object communication apparatus showing ultraelastic properties even at the transformation point (As point) of about -20 deg.C or below can be obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an antenna element used in mobile communication equipment and the like.

[0002]

2. Description of the Related Art In recent years, mobile communication devices such as car phones and mobile phones have been remarkably developed due to effective use of frequencies and improvement of systems in accordance with revision of the Radio Law. As the information-oriented society advances, the demand from business use to personal use is steadily progressing due to convenience, price reduction of service charges, expansion of service area, and so on. In addition, with the technological innovation of smaller size and lighter weight, the size of the original shoulder type has been reduced to the handheld type.
Now it is as large as the palm.

An essential element for such a wireless communication device is an antenna for transmitting and receiving radio waves. Among mobile communication devices, mobile phones, transceivers, and the like are required to have harsh reliability against environments such as vibration, shock, temperature and humidity because users handle them while moving outdoors. In particular, with an antenna extending to the outside of the device, there is a risk that the user may accidentally bend and deform it excessively. In addition, it is necessary to design in consideration of safety for users. Therefore, the antenna element is required to be as flexible as possible, and a spring material such as stainless steel or a piano wire is devised and processed. Recently, a new material, a superelastic alloy TiNi-based alloy, has been used.

Stainless wire used for general spring material,
The elastic limit of a piano wire is about 0.5%, and if it is strained more than that, permanent deformation will occur and it will not return to its original shape.

On the other hand, the superelastic TiNi alloy has a much larger elastic limit of about 8% as compared with the above-mentioned stainless wire and piano wire. That is, even if the elongation is up to 8%, no permanent deformation occurs and the original shape is restored. Paying attention to this superelastic function, orthodontic line,
It is used for catheter guide wires of medical equipment, clothes, rims of glasses, and antenna elements.

However, the conventional antenna element using the TiNi-based alloy utilizes the generation of the stress-induced martensite phase, and its superelasticity has temperature dependence.
Below the transformation temperature, there is a problem that the property of superelasticity is lost and the occurrence of residual strain due to deformation is unavoidable. The transformation temperature of conventional TiNi-based alloys is limited to about -20 ° C,
When bending stress is applied in a temperature environment below that, there is a problem that the strain remains and remains deformed.

[0007]

These conventional TiNi
It is an object of the present invention to provide a method for manufacturing an antenna element for mobile communication devices, which solves the problems of the antenna element using a system alloy and exhibits superelasticity even at a transformation temperature (As point) or lower.

[0008]

That is, according to the present invention, T
In a method of manufacturing a linear or pipe-shaped antenna element made of an iNiX (X = Cu, Cr, V, Mn, Zr) -based alloy, the alloy is processed at a processing rate of at least 30% or more and a temperature of 280 to 300 ° C. It is a method for manufacturing an antenna element, characterized in that heat treatment is performed between the antenna elements.

[0009]

When the working rate is set to 30% or more, the working structure is such that sliding deformation, which is permanent deformation, is unlikely to occur. By limiting the aging temperature to 280 to 300 ° C, superelasticity characteristics can be obtained at all environmental temperatures of -30 to 60 ° C in which the mobile communication device is used.

[0010]

EXAMPLES Examples of the present invention will be described in detail.
First, a Ti-51 Niat% alloy was melted by a high frequency vacuum melting method. The surface of the ingot obtained by melting is scratched, then heated to 900 ° C., hot groove roll,
A wire rod having an outer diameter of 1 mm was obtained through a surface pickling process and a cold wire drawing process. The processing rate of this wire was 30%.

As a result of measuring the transformation temperature of this drawn wire, it was -21 ° C.

Next, the drawn wire is 200 mm in length.
The sample was cut into several pieces of wire pieces. Divide each of these samples into several pieces at a temperature between 250 and 350 ° C.
Minute aging treatment was performed. Table 1 shows the results of tensile tests performed on each sample while changing the temperature of the sample.

[0013]

[Table 1] ◯: No residual strain ×: Residual strain −: Not measurable

In Table 1, the samples under the aging treatment conditions of 250 ° C.
Not softened and fractured in a tensile test. All the samples under the conditions of 280 ° C. and 300 ° C. exhibited superelasticity from −30 ° C. to 60 ° C. Further, the residual strain was confirmed at −30 ° C. for the sample under the condition of 320 ° C., and the residual strain was confirmed at −30 ° C. and −20 ° C. for the sample under the condition of 350 ° C. From these results, it was found that the samples treated under the conditions of 280 ° C. and 300 ° C. have superelasticity at all environmental temperatures in which the antenna element is used.

FIG. 1 shows a load-elongation curve obtained by measuring a sample treated under an aging treatment condition of 300 ° C. for 30 minutes, which is a manufacturing method of the present invention, with a tensile tester at different temperatures.
From the characteristic curve at −30 ° C. in FIG.
As can be seen from the characteristic curve of the sample at + 60 ° C, the load-elongation curve hardly changes from -30 ° C to + 60 ° C in this sample. The relationship between the amount of deformation and the load is almost linear and proportional. That is, the antenna element using the TiNi alloy manufactured by the manufacturing method of the present invention is
Good superelastic properties are exhibited at all temperatures between 30 ° C and + 60 ° C.

FIG. 2 shows the load obtained by measuring the sample treated under an aging treatment condition of 350 ° C. for 30 minutes with a tensile tester.
An elongation curve is shown. As can be seen from the characteristic curve at −30 ° C. in FIG. 2A and the characteristic curve at + 60 ° C. in FIG. 2G, residual strain that is permanent strain was confirmed at −30 ° C. and −20 ° C. in this sample. , -10 ℃ to + 60 ℃
Until then, there was almost no change in the load-elongation curve. However, when the yield stress is exceeded, the load-elongation curve has a rectangular shape in which the stress is substantially constant with respect to the elongation. Further, it can be seen that the portions where the curves where the stress is constant are parallel to each other change with temperature and have temperature dependence. That is, this parallel part is structurally a parallel part due to the appearance of a stress martensite phase and has temperature dependence,
As an antenna element, a 350 ° C. processing material is out of the scope of the present invention.

[0017]

According to the antenna element manufacturing method of the present invention, it is possible to obtain an antenna element exhibiting excellent superelasticity characteristics in all environmental temperatures in which mobile communication equipment is used, from -30 ° C to + 60 ° C. It will be possible.

[Brief description of drawings]

FIG. 1 is an aging treatment condition 300 in the manufacturing method of the present invention.
The characteristic view which shows the load-elongation curve of the sample processed at 30 degreeC x 30 minutes. FIG. 1A is a characteristic diagram when the measurement temperature is −30 ° C. FIG. 1B is a characteristic diagram when the measurement temperature is −20 ° C. Figure 1
(C) is a characteristic diagram at a measurement temperature of -10 ° C. Figure 1 (d)
Is a characteristic diagram when the measurement temperature is 0 ° C. FIG. 1E is a characteristic diagram when the measurement temperature is 20 ° C. FIG. 1F is a characteristic diagram when the measurement temperature is 40 ° C. FIG. 1 (g) is a characteristic diagram when the measurement temperature is 60 ° C.

FIG. 2 is a characteristic diagram showing a stress-strain curve of a sample treated under an aging treatment condition of 350 ° C. for 30 minutes. FIG. 2A is a characteristic diagram when the measurement temperature is −30 ° C. FIG. 2B shows a measured temperature of −20.
Characteristic diagram at ℃. FIG. 2C is a characteristic diagram when the measurement temperature is −10 ° C. FIG. 2D is a characteristic diagram when the measurement temperature is 0 ° C. FIG. 2E is a characteristic diagram when the measurement temperature is 20 ° C. Figure 2
(F) is a characteristic diagram when the measurement temperature is 40 ° C. FIG. 2G is a characteristic diagram when the measurement temperature is 60 ° C.

Claims (1)

[Claims] 1. TiNiX (X = Cu, Cr, V, M
In the method for manufacturing a linear or pipe-shaped antenna element made of an n, Zr) -based alloy, the alloy is at least 30%.
A method of manufacturing an antenna element, characterized in that the antenna element is processed at the above processing rates and heat-treated at 280 to 300 ° C.