JP2001049410A - Production of super-elasticity alloy wire rod, production of antenna parts of portable communication apparatus and antenna parts of portable communication apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve durability for repeated bending or the like by controlling the holding time in linear memorizing heat treatment to the one equal to or above the specified time and applying tension of the value equal to or above the specified one for applying linearity to a Ti-Ni alloy wire rod for a time equal to or above the specified one in the process of the holding to the memorizing treating temp. SOLUTION: A Ti-Ni alloy wire rod having an alloy compsn. contg., by atom, 48 to 52% Ni and 48 to 52% Ti, and in which the total content of Ni and Ti is controlled to >=95% is subjected to linear memorizing heat treatment in which this is held to a memorizing treating temp. decided within the range of 300 to 600 deg.C. At this time, the holding time in the linear memorizing treatment is controlled to >=4 min, and also, in the process of the holding to the memorizing treating temp., tension of >=1.5 kg/mm2 for the application of linearity is applied to the Ti-Ni alloy wire rod for >=1 min. The linear memorizing heat treatment is executed so that it is continuously carried in a tunnellike heating furnace having a heating source at the inside, and the length of a heating zone in which the heat treating temp. is secured is controlled to 1.5 to 10 m.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a superelastic alloy wire made of a Ti--Ni alloy, a method of manufacturing an antenna component of a portable communication device using the same, and a portable device realized by the method. The present invention relates to an antenna component of a communication device.

[0002]

2. Description of the Related Art Conventionally, an antenna of a mobile communication device such as a cellular phone sometimes bends or breaks due to a lateral load when being carried in a portable state. Therefore, in order to improve the durability against such a load, an antenna made of a superelastic alloy is used. Since the Ti-Ni-based superelastic alloy can reversibly recover the deformation with unloading even when a large deformation exceeding the normal elastic elongation range is applied, and is excellent in durability against repeated deformation, the above-described antenna It is suitably used for

[0003]

An antenna made of a superelastic alloy wire as described above is subjected to a linear memory heat treatment so that a transformation point contributing to the superelastic effect becomes a predetermined temperature. In this case, the transformation temperature of the Ti—Ni-based superelastic alloy can be adjusted by the components and the heat treatment conditions (temperature, holding time and cooling rate), as is well known. Usually, in order to memorize a linear shape in the superelastic alloy wire, a linear memory heat treatment is performed for 1 minute to several minutes. By this heat treatment, the transformation temperature of the superelastic alloy wire becomes
The temperature is adjusted so as to be in a temperature range suitable for exhibiting the superelastic effect.

[0004] By the way, superelastic alloy wires obtained by the above-mentioned linear memory heat treatment are required to have linearity at room temperature and durability against repeated deformation due to bending and elongation. As the number of antennas increases, it has been required to meet even more severe conditions regarding the durability of the antenna. Various techniques have been conventionally proposed to improve the repetitive durability characteristics of Ti-Ni-based superelastic alloy wires, and for example, attempts have been made to devise the conditions for the above-mentioned linear memory heat treatment, but there is room for improvement. Are many.

An object of the present invention is to improve the durability against repeated bending and the like by subjecting a Ti-Ni alloy wire to a linear memory heat treatment to form a superelastic alloy wire under a certain condition. An object of the present invention is to provide a method of manufacturing a superelastic alloy wire that can be used, a method of manufacturing an antenna component of a portable communication device using the same, and an antenna component of a portable communication device having excellent durability realized by the method. .

[0006]

Means for Solving the Problems and Actions / Effects In order to solve the above-mentioned problems, a method for producing a superelastic alloy wire according to the present invention has a Ni content of 48 to 52 atomic% and a Ti content of 4%.
8 to 52 atomic%, the total content of Ni and Ti is 95 atomic%
When performing a linear memory heat treatment on a Ti-Ni-based alloy wire having the above alloy composition at a memory processing temperature determined within a range of 300 to 600 ° C., a holding time of the linear memory heat treatment For more than 4 minutes,
In addition, during the holding at the memory processing temperature, a tension of 1.5 kg / mm ² or more for imparting linearity is applied to Ti-Ni.
It is characterized in that it is applied to a system alloy wire for at least one minute.

[0007] The superelastic alloy referred to in the present invention refers to an alloy capable of reversibly recovering a strain of 1% or more due to application of a load upon unloading.

When a linear memory heat treatment is applied to a Ti—Ni-based alloy wire, as is well known, the heat treatment is usually performed for one to several minutes so that the transformation point contributing to the manifestation of the superelastic effect becomes a predetermined temperature. It is performed in the form of applying. The present inventors have paid attention to the conditions of this linear memory heat treatment, secured the heat treatment holding time longer than before, and by applying a constant tension to the alloy wire during the temperature holding of the heat treatment. The inventors have found through experiments that linearity and high durability are realized, and have completed the present invention. The point is that the holding time of the linear memory heat treatment is set to 4 minutes or more, and the tension of 1.5 kg / mm ² or more for imparting linearity is given to Ti- while holding at the memory processing temperature.
The point is that it is applied to the Ni-based alloy wire rod for 1 minute or more. As a result, the obtained superelastic alloy wire has excellent linearity, and also has a remarkably improved repetition durability against bending and stretching.

If the holding time of the linear memory heat treatment is less than 4 minutes, the resulting superelastic alloy wire will have insufficient durability against repeated bending and stretching. The upper limit of the holding time is appropriately determined in consideration of the productivity of the superelastic alloy wire rod.
Since heating for more than a minute does not easily cause a further increase in the durability improving effect, this can be used as a guide for setting the upper limit value of the holding time. The above holding time is more desirably 6 to 8 minutes.

[0010] On the other hand, for tensioning for linearity imparting, at its level of less than 1.5 kg / mm ^2, good linearity of the superalloy wire obtained is not ensured. On the other hand,
If the tension level exceeds 10 kg / mm ² , the surface reduction (reduction in wire diameter) of the wire during heat treatment proceeds, and dimensional accuracy may not be obtained. The range of the tension is desirably 2 to
It is better to set within the range of 5 kg / mm ² .

Further, if the holding time in the linear memory heat treatment for applying tension is less than 1 minute, good linearity of the obtained superalloy wire cannot be similarly ensured. In addition, the upper limit of the holding time is appropriately determined in consideration of the productivity of the superelastic alloy wire rod. However, even if the holding time is maintained in a tension applied state for 5 minutes or more, it is difficult to further increase the linearity improving effect. This can be used as a guide for setting the upper limit value of the holding time.

The composition of the Ti—Ni alloy wire has a Ni content of 48 to 52 atomic%, a Ti content of 48 to 52 atomic%,
The total content of Ni and Ti is 95 atomic% or more. If a composition outside this range is used, the resulting superelastic alloy wire cannot have sufficient repetitive durability against bending and elongation. The temperature range of the linear memory heat treatment is 300 to
The temperature is 600 ° C., which is set by appropriately selecting a numerical value within the range according to the transformation temperature aimed at the alloy composition to be employed. However, if the heat treatment temperature is out of the above range, it becomes difficult to adjust the transformation temperature itself, and as a result, it becomes impossible to obtain a superelastic alloy wire having excellent durability characteristics.

In the present invention, preferably, the holding time at the memory processing temperature in the linear memory heat treatment is Ti
-The tension applied to the Ni-based alloy wire rod is 1.5 kg
/ Mm ^{2 for} at least 4 minutes (hereinafter referred to as a first holding step) and a tension of 1.5 kg / mm ² or more for 1 minute or more (hereinafter referred to as a second holding step). . The resulting superelastic alloy wire is bent and
The repetition durability against stretching or the like is further improved.
The tension level in the first holding step is more desirably less than 10 kg / mm ² .

In a preferred embodiment of the present invention, the linear memory heat treatment of the Ti—Ni alloy wire is performed while being continuously transported in a tunnel-shaped heating furnace having a heating source therein. The heating zone length of the heating furnace in which the linear memory heat treatment temperature is secured is set to 1.5 m to 10 m, and the in-furnace transfer speed of the wire rod is adjusted to 1.0 to 10 m / min. Superelastic alloy wires can also be heat-treated by an electric heating method, a dielectric heating method, or the like.However, in these methods, it is difficult to adjust the temperature. In some cases, the durability against the like may be insufficient. On the other hand, if a tunnel-shaped heating furnace that performs heating by radiation or convection from a heating source is used, it is easy to secure uniform heat, and a superelastic alloy having excellent durability can be obtained. In addition, the length of the heating zone is set to 1.5 m to 10 m in consideration of the installation space of the heating furnace and securing a sufficient heating holding time,
In this case, in order to secure a heat treatment holding time of 4 minutes or more in the heating zone, it is necessary to set the transport speed of the wire to 2.5 m / min or less. That is, if the transport speed is 2.5 m / min or more, the heat treatment holding time of 4 minutes or more cannot be secured in the above-described heating zone length. Further, setting the transport speed to less than 1.0 m / min is not realistic because it leads to an extreme decrease in productivity.

Next, the outer peripheral surface of the superelastic alloy wire produced by the above method can be coated with a polymer material in consideration of, for example, a case where the superelastic alloy wire is used as an antenna or the like. In this case, the following method can be adopted. That is, while continuously transporting the superelastic alloy wire subjected to the linear memory heat treatment in the longitudinal direction, the wire is brought into contact with a molten polymer material maintained at a temperature of 300 ° C. or less to coat the polymer material, and In order to suppress the change of the transformation point due to the thermal influence, within 300 seconds after the coating of the molten polymer material, the superelastic alloy wire coated with the polymer material is brought into contact with a cooling medium. Cool it.

Coating the superelastic alloy wire after the linear memory heat treatment with the polymer material which is melted by heating is likely to promote the change of the transformation point.
As a result of extensive studies by the present inventors, the temperature of the softened and melted polymer material is set to 300 ° C. or less, and the softened and melted polymer material is cooled within 300 seconds after the superelastic alloy wire is coated. In addition, the effect of suppressing the transformation point change can be obtained, and for example, the result does not affect the transformation start temperature Ms of the superelastic alloy wire. Therefore, the resulting coated superelastic alloy wire can maintain good linearity, does not deteriorate in bending and elongation, and can reduce variation among lots.

In the present invention, preferably, cooling water can be used as a cooling medium for contacting the superelastic alloy wire coated with the polymer material. Further, as a more preferable form, the superelastic alloy wire is coated with the polymer material by being passed through a molten polymer material supply section for supplying the molten polymer material, and then the molten polymer material is coated. The cooling water tank may be guided to a cooling water tank disposed immediately after the supply unit, and may be cooled by being immersed in the cooling water in the cooling water tank while continuing the conveyance. In any case, the cooling effect after coating can be further enhanced.

In the present invention, it is desirable that the temperature of the cooling water is adjusted to 60 ° C. or less and that the immersion time is set to 5 seconds or more. Cooling water temperature 60
If the temperature is higher than ℃, the cooling effect on the superelastic alloy wire immediately after coating cannot be obtained, and the effect of suppressing the transformation point change may be weakened. A sufficient cooling effect on the immediately following superelastic alloy wire cannot be obtained, and the effect of suppressing the transformation point change may be weakened.

For example, a wire having a wire diameter of 0.
When a wire having a thickness of 6 to 1.2 mm is made of the above-described Ti-Ni-based superelastic alloy wire, an elastic polymer having a softening temperature of 100 to 300 ° C is used as the polymer.
It is desirable to coat with a coating thickness of 0.2 to 0.6 mm. If the softening temperature of the elastic polymer material is lower than the lower limit of the above range, heat resistance is insufficient and practically hindered as a coated wire. Conversely, softening temperature is 300
C. or higher, the temperature of the molten polymer material at which a suitable fluidity can be obtained becomes too high, and the T
The transformation temperature of the i-Ni superelastic alloy wire is likely to change.

Further, the coating thickness of the polymer material is set to 0.2 to
The reason for setting the thickness to 0.6 mm is as follows. First, if the coating thickness is 0.2 mm or less, a sufficient protective effect as the coating cannot be obtained. On the other hand, if the coating thickness is 0.6 mm or more, on the contrary, the thermal effect of the molten polymer material on the wire becomes large, and the transformation point may be changed. The coating thickness of the polymer material is adjusted, for example, by adjusting the supply amount of the molten polymer material in the polymer material supply unit and the feed speed of the superelastic alloy wire passing through the polymer material supply unit. It becomes possible. That is, if the supply amount of the molten polymer material is reduced, the coating thickness is reduced, and if it is increased, the coating thickness is increased. Further, the coating thickness becomes thinner when the feed speed of the wire is increased, and the coating thickness becomes thicker when the feeding speed is reduced.
By appropriately adjusting these, a polymer material coating having the above thickness can be formed.

Further, it is desirable that the elastic polymer material is a thermoplastic urethane polymer material. According to this thermoplastic urethane-based polymer material, not only the softening temperature is within the above range, but also it is particularly excellent in integral molding when the continuous polymer material is coated on the outer peripheral surface of the Ti-Ni-based superelastic alloy wire. For example, even when a Ti or Ni-based scale layer is formed on the surface, a uniform and highly adhered coating state can be obtained. On the other hand, when this is used for an antenna or the like, a bending load accompanying bending and stretching is frequently applied, so that a material having high durability and deformation followability is required.
The above thermoplastic urethane polymer material satisfies such conditions.

For example, when the wire diameter is equal to 0.
A wire of 6 to 1.2 mm is composed of a Ti-Ni-based superelastic alloy wire mainly containing Ti and Ni, and by the above-described method, a constant tension is applied to the superelastic alloy wire together with the heat treatment. If it is applied, a highly durable superelastic alloy wire rod that achieves linearity and high durability can be obtained.

Next, in the method of manufacturing an antenna part of a portable communication device according to the present invention, the superelastic alloy wire obtained as described above is cut into a predetermined length, and the cut coated superelastic alloy wire is cut. The coating polymer material at both ends is peeled off and removed, a tip cover is attached to one of the peeling ends, and a mounting bracket is attached to the other peeling end. According to this method, linearity is ensured, and repeated bending and
An antenna component of a portable communication device having durability against follow-up deformability such as stretching can be suitably manufactured.

By adopting the above-mentioned manufacturing method of the present invention, the following antenna component of the portable communication device of the present invention is realized: Ni content of 48 to 52 atomic%, T
The alloy composition has an i content of 48 to 52 atomic%, a total content of Ni and Ti of 95 to 100 atomic%, a wire diameter of 0.6 to 1.2 mm, and a reverse transformation end temperature. Af
The antenna body is composed of a superelastic alloy wire whose temperature is adjusted to 15 to 40 ° C., and the following durability test is performed. That is, the base end of the antenna body is sandwiched between a pair of test holding members by 10 mm or more. At the same time, the tip of the antenna body extends linearly from the edge of the clamping surface of both test holding members, while both test holding members follow the clamping surface on the extension side of the antenna body and have a radius of curvature. 25m
An arc-shaped guide surface which is separated outward at m and a bending holding surface which follows the guide surface and is substantially perpendicular to the clamping surface are formed, and the extended portion of the antenna body is formed with the edge of the clamping surface. After bending the test holding member in a direction substantially perpendicular to the position where the tip side is in close contact with the bending holding surface along the guide surface, the returning operation is defined as one cycle, and the cycle is alternately performed on the test holding members on both sides. When the durability test is repeated, the number of cycles until the wire breaks is 5000 cycles or more.

In the above configuration, first, the antenna main body is made of the superelastic alloy wire of the present invention having the above-described composition, and the wire diameter is adjusted to a value suitable for the antenna.
6 to 1.2 mm. Further, the reason why the reverse transformation end temperature Af is adjusted to 15 to 40 ° C. is that when the temperature is outside this range, the superelastic effect cannot be sufficiently secured, and the return to bending deformation is not complete. This is because of difficulty.

On the premise of the above, the linear storage heat treatment
When the tension is 1.5kg / mm ²Less than 4 minutes
Above and 1.5 kg / mm²With the above tension applied
Applying the production method of the present invention for at least 1 minute in a state
Then, the above-mentioned endurance test was performed on the antenna body (in the experimental example described later).
Is called 25R bending test)
The number of cycles is more than 5,000 times.
Antenna parts with extremely excellent repeated durability characteristics
It is done.

Further, in the above-mentioned antenna component, the outer peripheral surface of the antenna body except for both end portions has a softening temperature of 10 °.
It can be covered with a thermoplastic urethane-based polymer material having a temperature of 0 to 300 ° C and a thickness of 0.2 to 0.6 mm. By forming the covering part of the antenna main body with the thermoplastic urethane-based polymer material as described above, the variation of the transformation point is small, the bending and stretching characteristics are good, and the antenna has excellent linearity. Parts are realized. Furthermore, the coating layer has excellent durability and deformation followability, and can maintain a good appearance over a long period of time.

[0028]

Embodiments of the present invention will be described below with reference to the drawings. The superelastic alloy wire is, for example, Ti-N
It is composed of a superelastic alloy such as an i-alloy. Specifically,
Ni content is 48 to 52 atomic%, Ti content is 48 to 5
An alloy having a content of 2 atomic% and a total content of Ni and Ti of 95 to 100 atomic% is used. This alloy has substantially the same or similar composition as that of a so-called TiNi-based shape memory alloy. For example, a high-frequency dielectric heating type vacuum melting furnace or a plasma melting method with relatively little component fluctuation is used to form Ti and -Ni. Is mixed in a predetermined amount in the above ratio to form an alloy ingot, which is manufactured by wire processing.

This wire rod processing can be performed, for example, as follows. First, as shown in FIG.
By a pair of rolling rolls 3 in which a predetermined recess 2 is formed,
Hot rolling at a temperature of 700 ° C to 950 ° C, and an appropriate diameter (φ
(4.5 mm). The round bar 1 obtained in this manner is placed at 500 ° C. to 800 ° C. using a warm drawing die 4.
C. Warm drawing is repeated several times to reduce the diameter. And
Finally, the wire is cold drawn by the cold drawing die 5 so as to have a desired wire diameter (for example, φ1.0 mm), and is wound around the coil 50. The wire diameter of this wire is 0.6-1.2m
m.

In a shape memory alloy such as a Ti—Ni alloy, the superelastic effect and the shape memory effect are expressed in a so-called two-sided relationship due to the transformation temperature of the thermoelastic martensitic transformation. More specifically, the relationship between the onset temperature Ms of martensitic transformation and the use temperature θ determines whether to use the superelastic effect or to use the shape memory effect. This is because the situation remains the same even if the composition of the alloy is the same (because, as described later, the transformation temperature can be changed depending on the heat treatment conditions even if the alloy has the same composition). In addition, Ti-N
In the i-based alloy, there are generally two stages between the three phases of a martensite phase on the lowest temperature side, an intermediate phase generally called an R phase generated on the higher temperature side, and a parent phase generated on the highest temperature side. It is known to cause metamorphosis. Of these, transformation between the R phase and the parent phase is widely used because of its high reversibility and low temperature hysteresis (= As-Ms: As is the onset temperature of reverse transformation). In the present invention, this R phase is also defined as being included in the martensite phase in a broad sense.

When utilizing the superelastic effect as in the present invention, it is necessary that Ms <θ. Ti-
When a Ni-based alloy wire is used as an antenna wire, Ms
<Θ, a deformation load such as bending is applied in the matrix state at the use temperature θ. The matrix undergoes a stress-induced martensitic transformation in such a way as to produce a variant with an orientation that gives the greatest strain to the direction of the deformation load. That is, the martensite phase is generated at θ which is higher than the original Ms. However, thermodynamically, the driving force of the martensitic transformation is supplemented by the elastic energy of the deformation, and the apparent Ms increases. It is interpreted to be. In this specification, Ms, As,
All transformation temperatures such as Af are defined as those measured in the state where no external load or constraint load is applied.

The above-mentioned deformation proceeds based on the generation and growth of the stress-induced martensite phase without accompanying the slip deformation of the crystal. From this state the temperature rises and the liquid thaws,
When the load is relaxed, the stress-induced martensite phase immediately reverse-transforms to the parent phase and returns to the state shown in FIG.
In other words, when the load is removed, the martensitic phase undergoes a reverse transformation and returns to its original shape, resulting in a behavior similar to elastic deformation (so-called transformation pseudoelasticity). Because it is considerably larger than the deformation, it is called the superelastic effect. In this case, it is desirable to satisfy Af <θ in order to almost completely return to the original shape when the deformation load is eliminated.

Next, as is well known, the transformation temperature of the shape memory alloy can be adjusted by heat treatment conditions (temperature, holding time and cooling rate). The wound wire 6 is subjected to a linear memory heat treatment for one to several minutes in order to memorize the linear shape. By this heat treatment, the transformation temperature (Ms point) of the wire is determined. The wire 6 drawn out from the coil 50 is inserted into a tunnel furnace while applying a certain tension to the wire 6 so that the wire 6 is straightened.
(For example, in the case of an antenna, it is heated to an appropriately adjusted temperature so as to obtain a transformation temperature showing a superelastic behavior at -20 ° C to 40 ° C, and then rapidly cooled by being poured into a coolant such as water. Thereafter, an acid washing step may be performed as a rust preventive treatment. In the case of a superelastic alloy, the Ms point is generally equal to or lower than room temperature, and is adjusted to 30 to -20 ° C. so that the deformation stress-induced martensitic transformation required for the expression of a sufficient transformation pseudoelastic effect occurs. The Af point is set to 15 to 20 ° C. The range of the linear memory heat treatment temperature in this case is 300 to 600 ° C.
It is. At the end of this process, the wire 6 is a super-elastic alloy wire 6 that stores a linear shape.

Next, the linear memory heat treatment step will be described with reference to FIG.
This will be described in more detail with reference to FIG. First, the wire coil 50 wound to a desired wire diameter is rotatably installed at the material supply position 7. On the other hand, at a winding position 8 at the end of the wire 6 fed from the wire coil 50 in the transport direction, a winding drum 9 for winding the wire 6 after the linear memory heat treatment is rotatably installed. A motor 11 provided with a pulse generator 10 is connected to the winding drum 9, and the rotation speed of the winding drum 9 is adjusted by controlling the motor 11 to adjust the feed speed (winding speed) of the wire 6. It can be controlled to be constant. In this manner, the wire 6 fed from the coil 50 at a constant feed speed reaches the heat treatment device 13 via the dancer roll 12.

The heat treatment apparatus 13 is configured as a tunnel-shaped (or annular) heating furnace, in which a resistance heating element 20 such as a resistance heating wire coil is disposed, and the wire 6 is radiated or convected by the energized heating. It is designed to be heated. The length L of the heating zone 13a for maintaining the temperature of the heat treatment apparatus 13 is set to 1.5 m or more and 10 m or less.
By controlling the rotation speed of the motor 11, the paper is continuously conveyed at a speed of 1.0 to 10 m / min.

The wire 6 that is continuously conveyed has a working temperature.
Endurance of bending and stretching while ensuring straightness
In order to impart heat resistance, the heat treatment
4 minutes or more (preferably 6 to 8 minutes) in the
Heat treatment is performed. Also, to ensure linearity, at least
1.5kg / mm for 1 minute (preferably 2-3 minutes) ²
Above (desirably 2 to 5 kg / mm²) Tension of wire 6
The heat treatment is performed in a state in which is added.

The tension applied to the wire 6 can be adjusted, for example, by adjusting the winding torque of the winding drum 9 or by providing a tension adjusting section 51 in the middle of the conveying path of the wire 6, for example, by adjusting the tension of the tension adjusting section 51. This can be performed by adjusting the position of the roller 52 or the like. In this case, the transported wire 6
Considering that the linear memory heat treatment is performed continuously, it can be said that a form in which the desired value of tension is fixedly and constantly applied is desirable. That is, in the linear memory heat treatment, the wire 6
, The tension of the above level is constantly applied.

On the other hand, according to the results of intensive studies by the present inventors, the tension applied to the wire 6 is 1.5 kg / m
In the state of less than m ² (preferably less than 1.0 kg / mm ² ), 4 minutes or more is secured (first holding step), and the tension is 1.
5 kg / mm ² or more for 1 minute or more (preferably 2 to
3 kg / mm ² ) (second holding step)
It has been found that it is desirable to further improve the repeated durability against bending and stretching. In such a process, for example, in the apparatus of FIG. 2, first, the tension level is set to be low to perform the first holding step, and subsequently, the same apparatus is used to set the tension level to be high to perform the second holding step. It can be implemented by performing a two-stage linear storage process. When these two holding steps are performed at different heat treatment holding times using the same apparatus,
For example, the holding time can be adjusted by the wire feed speed.

The wire 6 subjected to the direct memory heat treatment is
The superelastic alloy wire 6 stores a linear shape in a form showing a predetermined transformation temperature. The wire 6 after the linear memory heat treatment is immersed in a coolant such as water in the cooling bath 14 and rapidly cooled so that the transformation temperature does not change during cooling. As shown in FIG. 3, the upper part of the cooling tank 14 extends in the transport direction.
The cooling water supply unit 15 has a cross section perpendicular to the conveying direction of the wire 6 formed in a substantially inverted trapezoidal shape, and a receiving tank 16 for receiving the cooling water overflowing from the cooling water supply unit 15. Is recirculated from the receiving tank 16 to the cooling water supply unit 15. After the linear memory heat treatment, the wire 6 is cooled by the cooling water, thereby avoiding a change in the transformation temperature of the superelastic alloy wire 6. After cooling, an acid pickling step may be performed as a rust preventive treatment. The wire 6 having passed through the cooling bath 14 is wound around the winding drum 9 via the capstan 17.

For example, when the above-mentioned wire 6 is coated with a polymer material, the following steps can be performed. As shown in FIG. 9, the supply drum 29 around which the wire 6 after the above processing is wound is rotatably installed at a supply position 30. On the other hand, at a winding position 31 at the end in the transport direction of the wire 6 fed from the material supply position 30, a winding drum 32 for winding the coated wire 6 is rotatably installed. A motor 34 provided with a pulse generator 33 is connected to the winding drum 32, and the rotation speed of the winding drum 32 is adjusted by controlling the motor 34, so that the feeding speed (winding speed) of the wire 6 is adjusted. It can be controlled to be constant. The wire 6 fed out at a constant feed speed from the supply drum 29 in this manner reaches the polymer material coating machine 36 via the dancer roll 35.

This polymer material coating machine 36 is fitted with a male die 38 having a passage 37 through which the wire 6 is inserted in a substantially truncated conical central portion, and a conical portion of the male die 38. And a female die 39 that fits into the female die 39. The central part of the female die 39 is processed so as to form a gap, and a storage part 41 of the polymer material 40 is formed between the female die 39 and the tip of the male die 38. Have been. The exit side of the female die 39 is perforated to have substantially the same diameter as the desired thickness of the polymer material coating. The male and female dies 38, 39 are normally loosely fitted at a certain interval in a normal state, and are heated to a temperature higher than the melting point of the polymer material within this interval, and are softened and melted. The polymer material 40 in the state is press-fitted from one end side and reaches the storage portion 41 from the annular portion of the male die 38.

The wire 6 that has reached the polymer material coating machine 36
While passing through the storage part 41 through the passage 37 of the male die 38, while adjusting the coating thickness of the polymer material 40 by the supply amount of the softened and melted polymer material 40 and the feed speed of the wire 6 The polymer material 40 is coated on the outer peripheral surface. Normally, fine surface irregularities exist on the outer peripheral surface of the wire of the wire 6, and when the wire 6 passes through the storage portion 41, the polymer material 40 that has been softened and melted has the fine surface irregularities. It will penetrate and adhere to the part at least partially buried. The polymer material 40 that has been softened and melted is controlled in a heating state in which the melting point of the polymer material is equal to or higher than the melting point of the polymer material. The temperature of the softened and melted polymer material is set to 300 ° C. or less, and the time from exiting the storage section 41 to cooling is set to within 300 seconds.

The polymer material 40 coated on the wire 6 is made of a thermoplastic polymer material, particularly thermoplastic rubber or elastomer, which is excellent in integral molding, follows the bending and deformation of the coil after coating, and has durability. It is advantageous. In particular,
Polyurethane-based thermoplastic elastomer, polyolefin-based thermoplastic elastomer, polystyrene-based thermoplastic elastomer, polyester-based thermoplastic elastomer, poamide-based thermoplastic elastomer, 1,2-polybutadiene-based thermoplastic elastomer, ethylene-vinyl acetate-based thermoplastic elastomer, poly There are vinyl chloride-based thermoplastic elastomers, natural rubber-based thermoplastic elastomers, fluoro rubber-based thermoplastic elastomers, trans-polyisoprene-based thermoplastic elastomers, chlorinated polyethylene-based thermoplastic elastomers, and the like. A polyurethane thermoplastic elastomer, which is a polymer material, can be suitably used in the present invention.

The coated superelastic alloy wire 42, which is covered with the polymer material 40 in close contact with the outer peripheral surface, is provided in a primary cooling tank 43.
Will be cooled immediately. As shown in FIG. 10, the primary cooling tank 43 has a cooling water supply unit 44 whose upper part is formed in a substantially inverted trapezoidal cross section orthogonal to the transport direction of the coated superelastic alloy wire 42 over the transport direction. Receiving tank 4 for receiving the cooling water overflowing from cooling water supply section 44
The cooling water overflows from the receiving tank 45 to the cooling water supply unit 44. After coating with the polymer material 40,
By immediately cooling the coated superelastic alloy wire 42 with the cooling water, a change in the transformation temperature of the superelastic alloy wire due to the thermal effect of the resin coating is avoided. The temperature of the cooling water is 20 to 50 ° C., and the immersion time is 5 to 50 seconds.

From the coated superelastic alloy wire 42 that has passed through the primary cooling tank 43, water adhering to the outer peripheral portion is removed by a drainer roll 46 that rotates at substantially the same speed as the winding speed. The outer diameter after coating (and thus the coating thickness of the polymer material) is measured. Next, the coated superelastic alloy wire rod 42 is again water-cooled in a secondary cooling tank 48 having substantially the same configuration as described above, and the capstan 4
After passing through 9, it is wound on a winding drum 32. The coated superelastic alloy wire 42 wound on the winding drum 32 is processed according to its use.

FIG. 4 illustrates a portable telephone 18 as an example of a mobile communication device, which comprises a telephone body (device body) 19 and an antenna 20 attached thereto. As shown in FIG. 5, the antenna 20 includes an antenna body 21 formed in a wire shape, a tip cover 22 attached to one end thereof, a mounting bracket 23 attached to the other end thereof, and an antenna Attach the main body 21 to the mounting bracket 2
On the third side, a connection screw 24 for connecting to the telephone body 19 is provided.

For example, when processing the superelastic alloy wire 6 into the mobile communication device antenna 20 as described above, it can be attached in the following manner. Normal,
This kind of antenna 20 has its outer peripheral surface covered with a coating 25 such as a polymer material to protect the wire 6 itself or from the viewpoint of aesthetics. First, the wire 6 is fixed to a predetermined length. After slicing, the coated polymer material 25 at both ends is peeled off to expose the strand. As shown in FIG. 6 (a), the fixedly cut coated wire (antenna body) 21
Is inserted through a mounting hole 23a of the mounting bracket 23, and the mounting bracket 23 is caulked radially from the outside by a caulking mold 26 as shown in FIG.
The antenna body 21 and the mounting bracket 23 are integrated. As shown in FIGS. 6 (a) and 6 (b), the caulking mold 26 has a small diameter portion 26b and a large diameter portion 26c formed in the cavity portion 26a, and as shown in FIG. 6 (c). The mounting member 23 is compressed in the radial direction by the small diameter portion 26b to form the caulked portion 23b, and the large diameter portion 23c is formed at the end corresponding to the large diameter portion 26c. A step 23d is formed at the boundary between the swaged portion 23b and the large diameter portion 23c.

As shown in FIG. 7, the connection screw 24 has a male screw portion 24a formed on the outer peripheral surface thereof, and a through hole 24b formed in the axial direction thereof, through which the antenna body 21 is inserted. Here, the connection screw 24 is
The inner diameter of b is set so as to correspond to the outer diameter of the caulked portion 23b of the mounting bracket 23, so that the mounting bracket 23 is prevented from coming off at the aforementioned step 23d.

When mounting the antenna 20 on the telephone body 19, as shown in FIG.
The mounting is completed by inserting the male screw portion 24a of the connection screw 24 into the female screw portion 19b formed on the connection hole 19a side, while inserting it into the connection hole 19a formed on the side. At this time, the connection hole 1
It comes into contact with an antenna terminal 19c formed at the bottom of 9a.

[0050]

[Experimental Examples] Next, in order to confirm the effects of the present invention, the following various experiments were performed. First, as a superelastic alloy material, a TiNi-based alloy material having a composition of 56 atomic% and the remaining Ti was melted by high-frequency melting, and was hot-rolled, warm-drawn, and cold-drawn to a wire diameter of 0.8 mm. Was obtained.

(Experimental Example 1) The above superelastic alloy wire was subjected to a linear memory heat treatment by a heat treatment apparatus 13 shown in FIG. The straight line storage process is performed by the above-described two-stage process. In the first holding process, the tension level is set to 1.0 kg / mm ² ,
The retention time was set in the range of 0 to 10 minutes. On the other hand, in the second holding step, the tension level was set to 2 kg / mm ² and the holding time was variously set within a range of 1 to 3 minutes (that is, the total heat treatment holding time for the wire 6 was 2 to 13 minutes). . However, the heat treatment apparatus 13 has a set heat treatment temperature of 45.
This is a tunnel furnace having a zone length of 6 m, which is maintained at a temperature of 0 ° C. (± 1 ° C.). The wire feed speed is 0.6 to 2 m / min in the first holding step, and 2.0 to 2.0 m in the second holding step. 6.0m
/ Min.

A length of 200 mm is cut out from the superelastic alloy wire after the linear memory heat treatment by electric discharge machining, and a test piece 27 of the form shown in FIG. Was used to perform a 25R bending test.

That is, the base end of the wire rod piece 6 ′ is
mm between the pair of test holding members 28, 28 and the pressing surfaces 2 of the test holding members 28, 28.
The distal end side of the wire rod 6 is linearly extended from the edges of 8a and 28a. On both test holding members 28, 28, the arcuate guide surfaces 2 that follow the pressing surfaces 28a, 28a on the extension side of the wire rod 6 'and are separated outward with a radius of curvature of 25 mm are provided.
8b, 28b and bending holding surfaces 28c, 28c that follow the guide surfaces 28b, 28b and are substantially perpendicular to the clamping surfaces 28a, 28a. After bending the extending portion of the wire piece 6 'to the test holding member 28 in a direction substantially perpendicular to the edge of the pinching surface 28a, along the guide surface 28b, to the position where the distal end is in close contact with the bending holding surface 28c, and then returns. The operation to be performed is defined as one cycle, and the cycle is alternately repeated for the test holding members 28 on both sides. Then, the evaluation is performed based on the number of endurance cycles at that time, with the endurance until the wire is broken. Table 1 shows the results.

[0054]

[Table 1]

That is, from the results shown in Table 1, the heat treatment apparatus 1
The heat treatment time of No. 3 is set to 4 minutes or more, and by applying tension in the longitudinal direction of the superelastic alloy wire 6 for at least 1 minute or more of the heat treatment time, the number of endurance cycles is remarkably improved, and 5,000 times or more is achieved. You can see that it is done. Conversely, if the heat treatment time is less than 4 minutes, the number of endurance cycles is low. Therefore, when performing the linear memory heat treatment on the superelastic alloy wire 6, the heat treatment time is set to 4 minutes or more, and at least one of the heat treatment times is set.
It can be seen that by applying tension in the longitudinal direction of the superelastic alloy wire for minutes, a highly durable superelastic alloy wire 6 excellent in repeated bending durability can be obtained.

(Experimental Example 2) The heat treatment time of Experimental Example 1 was set to 10
For at least 3 minutes of this heat treatment time, a polymer material was coated on the wire rod to which tension was applied in the longitudinal direction using the apparatus shown in FIG. However, polyurethane was used as the polymer material, and the temperature of the molten polymer material at the time of coating was set variously in the range of 150 to 350 ° C. The coating thickness was 0.4 mm. Further, the primary cooling tank 43 (the temperature of the cooling water is 25
° C) to the inlet and adjust the wire feed speed to 0.0
It was fixed at 4 m / sec. As a result, the time from when the polymer material is coated on the wire until it is immersed in the cooling water is 5 to 3 times.
It is set to various values of 0 seconds.

Then, a test piece for measuring the transformation point was cut out from the superelastic alloy wire. While the test piece was cooled and heated by DSC (differential scanning calorimeter), a differential heat curve was obtained, and the Ms point (martensite transformation start temperature) was read as the transformation temperature. Table 2 shows the results.

[0058]

[Table 2]

That is, from the results in Table 2, it is found that the dispersion temperature of the transformation point is small by maintaining the melting temperature of the polyurethane (polymer material) at 300 ° C. or lower, and the change rate of the transformation point at 350 ° C. It can be read that it is great. Further, if the coating is immersed in cooling water within 300 seconds after the coating, the variation of the transformation point is small, but the change of the transformation point becomes large at 300 seconds. Therefore, when a superelastic alloy wire is coated with a polymer material, the melting temperature is set to 3
While maintaining the temperature at not more than 00 ° C., and immersing the coated superelastic alloy wire in cooling water within 300 seconds after the coating of the molten polymer material, the transformation point due to the thermal influence at the time of coating the polymer material is obtained. Can be suppressed.

(Experimental Example 3) The above-mentioned wire was coated with a polymer material using the apparatus shown in FIG. However, polyurethane is used as the polymer material, the temperature of the molten polymer material at the time of coating is 160 ° C., and the coating thickness is 0.4 mm.
And Further, the distance from the exit side of the female die 39 to the entrance of the primary cooling tank 43 was 0.5 m, and the wire feed speed was fixed at 0.04 m / sec. Thereby, the cooling water temperature of the primary cooling tank 43 is set to various values of 20 to 70 ° C.
Further, the time during which the wire after coating the polymer material was immersed in the cooling water was set to various values of 5 to 60 seconds by changing the dimensions of the primary cooling tank 43.

Then, a test piece for measuring the transformation point was cut out from the superelastic alloy wire by electric discharge machining. While the test piece was cooled and heated by DSC (differential scanning calorimeter), a differential heat curve was obtained, and the Ms point (martensite transformation start temperature) was read as the transformation temperature. Table 3 shows the results.

[0062]

[Table 3]

That is, from the results shown in Table 3, when the temperature of the cooling water is 50 ° C. or less and the immersion time exceeds 10 seconds, the change in the transformation point tends to be small. It can be seen that when the immersion time is 10 seconds or less at a temperature equal to or higher than 0 ° C., the variation in the transformation point tends to increase. Therefore, when the temperature of the cooling water is 50 ° C. or less and the immersion time is 20 seconds or more, it is possible to obtain a sufficient cooling effect for the wire coated with the polymer material, and furthermore, to suppress the change of the transformation point. It turns out that it is desirable for obtaining the effect.

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing a manufacturing process of a superelastic alloy wire.

FIG. 2 is an explanatory view schematically showing the method of the present invention.

FIG. 3 is an enlarged side view of a cooling tank.

FIG. 4 is a front view of a mobile phone.

FIG. 5 is a front view of an antenna formed of a superelastic alloy wire.

FIG. 6 is a process explanatory view showing a method of joining another member to the antenna main body by caulking.

FIG. 7 is a sectional view showing an attachment structure of the antenna to the telephone body.

FIG. 8 is an explanatory view showing a method of a 25R bending test.

FIG. 9 is an explanatory view schematically showing a polymer material coating method.

FIG. 10 is an enlarged side view of the primary cooling tank.

[Explanation of symbols]

 Reference Signs List 6 wire rod 13 heat treatment device 18 portable telephone (mobile communication device) 19 telephone body (device main body) 20 antenna 21 antenna body 23 mounting bracket 23b caulking portion 27 test device 28 test holding member 36 polymer material coating machine

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C22F 1/00 691 C22F 1/00 691C 693 693A 694 694Z

Claims (6)

[Claims] 1. A Ni content of 48 to 52 atomic%, a Ti content of 48 to 52 atomic%, and a total content of Ni and Ti of 9
When performing a linear memory heat treatment on a Ti—Ni-based alloy wire having an alloy composition of 5 atomic% or more by maintaining the temperature at a memory processing temperature determined within the range of 300 to 600 ° C., The holding time of the heat treatment is set to 4 minutes or more, and during the holding at the memory processing temperature, the tension of 1.5 kg / mm ² or more for imparting linearity is applied to the Ti-N.
A method for producing a superelastic alloy wire, wherein the method is applied to the i-type alloy wire for at least one minute. 2. The method according to claim 1, wherein the storage processing is performed in the linear storage heat treatment.
The holding time at the processing temperature is different from that of the Ti-Ni alloy wire.
1.5 kg / mm ²Less than
10 minutes or more and the tension is 1.5 kg /
mm²2. The method according to claim 1, wherein said condition is maintained for at least one minute.
Manufacturing method of super elastic alloy wire. 3. The linear memory heat treatment of the Ti—Ni-based alloy wire is performed while being continuously transported in a tunnel-shaped heating furnace having a heating source therein, and the temperature of the linear memory heat treatment is ensured. The production of a superelastic alloy wire according to claim 1 or 2, wherein a heating zone length of the heating furnace is 1.5 m to 10 m, and a transfer speed of the wire in the furnace is adjusted to 1.0 to 10 m / min. Method. 4. While continuously transporting the superelastic alloy wire subjected to the linear memory heat treatment in the longitudinal direction, the wire is brought into contact with a molten polymer material maintained at a temperature of 300 ° C. or less to coat the polymer material, In order to suppress the change of the transformation point due to the thermal effect at the time of coating of the polymer material, the superelastic alloy wire coated with the polymer material is removed within 300 seconds after the coating of the molten polymer material. The method for producing a superelastic alloy wire according to any one of claims 1 to 3, wherein the superelastic alloy wire is cooled by being brought into contact with a cooling medium. 5. The superelastic alloy wire according to claim 1 is cut into a predetermined length, and the coated polymer material at both ends of the cut superelastic alloy wire is peeled off.
Remove and attach the tip cover to one of the peeling ends,
A method for manufacturing an antenna component of a portable communication device, wherein a mounting bracket is attached to the other peeled end. 6. The Ni content is 48 to 52 atomic%, the Ti content is 48 to 52 atomic%, and the total content of Ni and Ti is 9%.
An antenna body made of a superelastic alloy wire having an alloy composition of 5 to 100 atomic%, a wire diameter of 0.6 to 1.2 mm, and a reverse transformation end temperature Af adjusted to 15 to 40 ° C. The following durability test is performed: the base end of the antenna main body is sandwiched between a pair of test holding members by 10 mm or more, and the antenna main body is cut from the edge of the pressing surface of both test holding members. The test holding member has an arc-shaped guide surface that follows the clamping surface on the extension side of the antenna main body and is separated outward with a radius of curvature of 25 mm. A bending and holding surface is formed following the guide surface and substantially perpendicular to the clamping surface, and the extended portion of the antenna main body is placed on the test holder in a direction substantially perpendicular to the edge of the clamping surface. An endurance test in which the operation of returning to the holding member after bending to a position where the tip side is in close contact with the bending holding surface along the guide surface is set as one cycle, and the cycle is alternately repeated for the test holding members on both sides. The number of cycles until the wire breaks is 500
An antenna component for a portable communication device, wherein the antenna component has 0 cycles or more.