JPH1065417A - Core member for antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna core member which enables press pressing without softening processing and indicating a superelasticity at room temperature by adopting a shape memory alloy having a specific composition for the core member. SOLUTION: A plug 3 is fitted to an end of an antenna use core member 2 by applying press processing to the end. The core member 1 indicates a superelasticity at normal use temperature (environment temperature of the antenna in use, nearly -10 to 40 deg.C), the composition is indicated as Ti50 Ni50-x Fex and is made of a shape memory alloy with X=0.2-2.0. The wire member of the shape memory alloy is preferably hot-processed at a temperature of 350-550 deg.C after cold strip of 30 to 60% of final processing rate. Furthermore, press processing is preferably applied to one point of the core member 1 or over. Moreover, the wire material of the shape memory alloy is formed into a line or a coil shape and the outside if preferably coated by a resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core material for an antenna used in a wireless device such as a portable telephone, in which the antenna is prevented from being bent or cut.

[0002]

2. Description of the Related Art Shape memory alloys (TiNi alloy, CuZn
It is well known that Al alloys have a remarkable shape memory effect accompanying the reverse transformation of martensitic transformation. It is also well known that in the matrix state of the reverse transformation, good superelasticity is exhibited. A spring made of shape memory alloy (superelastic alloy) showing superelasticity releases the deformation at the same time as 8% elongation strain is released.
Unlike a piano wire or the like, it has the advantage that it can be used as a spring without having to be coiled.

[0003] Conventionally, a steel wire such as a piano wire has been used as an antenna core material of a mobile phone. However, there are disadvantages such as easy bending and breaking. In addition, in order to solve these problems, using a superelastic alloy as a core material,
Japanese Utility Model Application Laid-Open No. 63-68207 and Japanese Patent Application Laid-Open No. Hei 3-16402 propose a superelastic alloy as the core material of the antenna in practical use. However, the superelastic alloy used for both the patent proposal and practical use is Ti-Ni
Alloy or Ti-Ni-X alloy (X = Cr, V, Co)
Met.

FIG. 1 shows an external view of a mobile phone antenna. The antenna is attached to the mobile phone via a plug or the like. Figure 2 shows the installation of the antenna core and the plug.
As shown in (1), in order to prevent pull-out, the ends of the core material are generally pressed and attached. In FIG.
4A is a front view of a pressed portion of the antenna core material, and FIG. 5B is a side view of the pressed portion.

[0005]

By the way, in the case of a conventional antenna core material using a superelastic alloy, it is generally necessary to apply a softening treatment to the core material during press working, which is one of the causes of high cost. It has become.

The present invention provides an antenna core material which can be pressed without subjecting the antenna core material to a softening treatment and which exhibits superelasticity at a normal temperature.

[0007]

The antenna core material according to the present invention is characterized in that the core material exhibits superelasticity at a normal temperature (indicating the use environment temperature of the antenna, the range is approximately -10 to 40 ° C),
The composition is indicated by Ti ₅₀ Ni _50-x F _x , where X = 0.5-2.5.
0.
In addition, the wire rod of the shape memory alloy is used in a final processing rate of 30 to 60.
% Cold working, followed by heat treatment at 350 to 550 ° C., characterized in that the core material made of the shape memory alloy is pressed at one or more locations, and further, the shape memory alloy wire is It is characterized in that it is formed in a linear or coil shape, and its outside is covered with a resin.

As a core material for an antenna, Ti ₅₀ Ni _50-x F
e _x alloy (wherein, 0.5 ≦ X ≦ 2.0) by the use of, and excellent superelastic properties without the softening treatment enables pressing, and at customary temperatures. Also,
When the outer surface of the superelastic alloy material is covered with a resin, good bending durability can be obtained.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described.

An alloy having a composition shown in Table 1 was obtained by a high-frequency vacuum melting method.

[0011] *: Comparative example Press workability ○: Processable, △: Difficult to process, ×: Crack generation Super elastic characteristic residual strain ○: <1.5 mm, Δ: <2 mm, ×:> 2 mm

After hot-working the obtained alloy billet, annealing and cold-working were repeated to produce a wire having a final working rate of 40% and a wire diameter of 1 mm. The obtained wire was heat-treated at 450 ° C. to produce a linear spring material and subjected to a three-point bending test. The support point length is 25mm and its center is up to 6
mm, push and unload the load at -10 ° C and 4
The measurement was performed at 0 ° C. and the residual strain was measured. Pressing was performed to a thickness of 0.5 mm using a hydraulic press. Further, experiments were performed in which the final processing rate and the heat treatment conditions were changed. The results are also shown in Table 1. The residual strain is defined in FIG.

As is apparent from Table 1, Ti ₅₀ Ni _50-x
In a Fe _x alloy, X is out of the composition range of 0.5 or more and 2.0 or less,
And the final processing rate is 30-60%, and the heat treatment temperature is 35
When the temperature is outside the range of 0 to 550 ° C., one of the press workability and the superelastic property, or both, are inferior.

[0014]

As described above, according to the present invention, an antenna core material which exhibits superelasticity in a normal temperature range and can be pressed without softening is obtained. Further, the manufacturing cost can be reduced by omitting the softening step.

[Brief description of the drawings]

FIG. 1 is an external view of an antenna.

FIG. 2 is a diagram showing a pressed portion of a core material for an antenna. FIG.
(A) is a front view of a press working part. FIG. 2B is a side view of the press working unit.

FIG. 3 is a load-displacement curve diagram of a superelastic alloy.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cap 2 Antenna core material 3 Plug 4 Front view of pressed part of antenna core material 5 Side view of pressed part of antenna core material

Claims (4)

[Claims] 1. The composition exhibits superelastic properties at a normal temperature, and has a composition
Ti ₅₀ Ni _50-x F _{x in} atomic% (where 0.5 ≦ X
≦ 2.0) A core material for an antenna, comprising a shape memory alloy represented by the following formula: 2. The processing rate of the shape memory alloy according to claim 1 is 3
A core material for an antenna, wherein the core material is subjected to a heat treatment at 350 to 550 ° C. after a cold working of 0 to 60%. 3. A core material for an antenna, wherein at least one part of the shape memory alloy which has been subjected to a heat treatment after the cold working according to claim 2 is pressed. 4. A core material for an antenna, wherein the wire made of the shape memory alloy according to claim 2 or 3 is formed in a linear shape or a coil shape, and the outside thereof is covered with a resin.