KR20070020458A - High-precision foamed coaxial cable - Google Patents

Abstract

The object of the present invention is to reduce the change in shape of the insulator and the outer conductor even when mechanical stress such as bending, torsion or slippage is added to the cable, so that the appearance and the outer diameter can be maintained, and the variation in the characteristic impedance can be reduced. To provide. A plurality of conductors are formed in the inner conductor 1 formed by combining the conductors, the insulator 2 formed by winding the porous tape body 21 around the outer conductor of the inner conductor 1, and the outer circumference of the insulator 2. In the high-precision foamed coaxial cable 10 composed of the outer conductor 3 formed by braiding the fine wires, the insulator 2 has a round shape in the outer shape and an outer diameter of the insulator 2 immediately after being wound. Reduction ratio 2 to 4 with respect to the outer diameter of the outer conductor 3, and the outer shape of the outer conductor 3 in a round shape, and the outer diameter of the outer conductor 3 to the outer diameter of the outer conductor 3 immediately after braiding. It shape | molds to% and let the precision of the characteristic impedance value be ± 1 kPa.

Inner conductor, insulator, outer conductor, coaxial cable, porous tape

Description

High precision foam coaxial cable {HIGH-PRECISION FOAMED COAXIAL CABLE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-precision foamed coaxial cable in which the insulator of the inner conductor outer periphery is formed by a porous tape body, and the outer conductor is formed of a braided shield body, and in particular, even when mechanical stress such as bending and torsion is added, changes in characteristic impedance values Low precision foam coaxial cable.

In recent years, with the progress of the highly information society, there is a growing demand for speeding up transmission speeds and improving transmission accuracy of information communication devices and test and inspection devices for semiconductor devices used in the information communication devices. For this reason, also in the coaxial cable and coaxial cord applied to these apparatus, apparatus, etc., the speed of transmission speed and the improvement of transmission precision are calculated | required.

In the transmission characteristics of the coaxial cable, the relative dielectric constant of the insulator and the outer diameter of the inner conductor and the insulator are involved, and the smaller the value of the relative dielectric constant, the better the transmission characteristics, and the ratio and the outer diameter of the inner conductor and the insulator. Variation is greatly involved. In particular, with respect to characteristic impedance and capacitance, the dielectric constant of an insulator is small, the fluctuation | variation is small, and the fluctuation | variation of the outer diameter (inner diameter of a shield layer), etc. of an inner conductor and an insulator is small, and their shape is more round cylinder shape. It is ideal to be formed.

As a high-precision foam coaxial cable which made the fluctuation | variation of a characteristic impedance value small, the coaxial cable of patent document 1 is known, for example.

Patent document 1 discloses an inner conductor in which a plurality of conductive wires are combined, a low dielectric constant foam insulator made of a porous tape body formed on the outer periphery of the inner conductor, and an outer side made of a plurality of conductive fine wires braided on the outer periphery of the foam insulator. In a high-precision foam coaxial cable composed of a conductor and an outer sheath made of a resin having heat resistance formed on the outer circumference of the outer conductor, the precision of the outer diameter of the inner conductor is 4/1000 mm or less, and the accuracy of the outer diameter of the foamed insulator Is ± 0.02 mm, the shape is formed in the shape of a circle, the precision of the outer diameter dimension of the outer conductor is ± 2% of the center value of the outer diameter, and the shape is formed in the shape of a circle, and the interior is provided with a foam insulator. Disclosed is a high-precision foamed coaxial cable in which the accuracy of characteristic impedance values between a conductor and an external conductor is ± 1 kW.

According to the high-precision foam coaxial cable described in Patent Document 1, it is possible to reduce the fluctuations in the irregularities and outer diameters of the outer conductors, insulators, and outer conductors constituting the high-precision foamed coaxial cable, thereby improving the accuracy of the outer diameter dimension, thereby improving the accuracy of each member. It can be made circular and can reduce fluctuations in characteristic impedance.

Patent Document 1: Japanese Patent Laid-Open No. 2003-234026

However, according to the conventional high precision foamed coaxial cable of Patent Document 1, in order to reduce the fluctuations in the characteristic impedance of the cable, the outer diameter of the insulator and the outer conductor is set to a predetermined value and the outer shape is as circular as possible. Secondary molding is performed by pressing the insulated core and the outer conductor core through a die having a predetermined inner diameter. However, the secondary molding is molded to make the outer diameter of the insulator and the outer conductor a predetermined value and to make the respective shapes the original. Since it is only present, the insulator and the outer conductor are not fastened, and the insulator does not say that the holding force holding the inner conductor and the shape holding force holding the shape of the insulator itself are sufficiently strong. In addition, in the external conductor, since molding was not performed in consideration of keeping the thickness constant, it was not possible to sufficiently reduce the fluctuation of the thickness of the external conductor and to closely adhere the external conductor and the insulator.

Therefore, there is still room for improvement in the problem that the outer diameter and the outer shape change and the characteristic impedance value changes accordingly when mechanical stress such as bending, torsion or slippage is added to the cable. This problem is inevitably a problem in the case of an electric wire or a cable which constitutes an insulator by winding a porous tape body having a porosity of 60% or more, and in a cable applied to a test and inspection device such as the semiconductor element described above. It is a problem that must be solved.

In addition, the high-precision foam coaxial cable is applied to, for example, a test / inspection apparatus for an information communication device and a semiconductor element applied to the device, but the characteristics required for the coaxial cable applied to the device and the device have flexibility, The influence of mechanical stress such as bending, torsion and slippage is small, the transmission characteristics, in particular, the characteristic impedance value is stable, and the variation of the characteristic value is small even when mechanical stress is added.

Here, the coaxial cable has flexibility and as conditions for withstanding mechanical stress such as bending, torsion, and slipping,

(1) Each element wire constituting the inner conductor has flexibility, and each element wire can move when twisted wire is used.

(2) The inner conductor and the insulator are not closely integrated and can be moved individually.

(3) The outer conductor is composed of a braid and the movement of each element wire of the braid is free.

(4) The insulator and the outer conductor are not closely integrated and can be moved individually.

(5) The outer conductor and the shell are not integrally integrated and can be moved individually.

Such conditions are required, that is, that each member constituting the cable is free.

On the other hand, as a condition for improving the accuracy of the characteristic impedance value of a coaxial cable,

(1) Each element wire constituting the inner conductor is integrally formed in a round shape, and the fluctuation of the outer diameter is small.

(2) The insulator has a constant dielectric constant, is formed in a round shape, has small fluctuations in the outer diameter, and is integrally integrated with the inner conductor. Moreover, there is a shape holding force of the insulator itself.

(3) The outer conductor is integrally formed in a round shape, and there is no variation in outer diameter and thickness, and the outer conductor is tightly integrated with the insulator.

(4) The outer shell is intimately integrated with the outer conductor and regulates the movement of the outer conductor in the outer shell.

In order to achieve the cabling and improve the characteristic impedance value, the shape holding force of the insulator is required, and the close integration of each member and the round shape are completed to reduce the fluctuation of the outer diameter and the relative dielectric constant. This condition becomes an indispensable condition.

In other words, the coaxial cable is flexible, and it is completely opposite to the conditions to withstand mechanical stress such as bending, torsion, and slippage, and to improve the accuracy of the characteristic impedance value. It is difficult to realize a coaxial cable that can withstand even when a mechanical stress is added, and that the characteristic impedance value is accurate.

Accordingly, an object of the present invention is to provide a high-precision foam coaxial cable that can solve the above problems.

MEANS TO SOLVE THE PROBLEM In order to achieve the said objective, in order to achieve the said objective, the internal conductor comprised by combining a conductor, the insulator comprised by winding a porous tape body in the outer periphery of the said inner conductor, and the braided several conductive fine wire in the outer periphery of the said insulator In the high-precision foam coaxial cable composed of an outer conductor, the outer shape of the insulator is round and the outer diameter of the insulator is molded at a reduction ratio of 3 to 5% with respect to the outer diameter of the insulator immediately after the winding, and The outer shape of the outer conductor is round and the outer diameter of the outer conductor is molded at a reduction ratio of 2 to 4% with respect to the outer diameter of the outer conductor immediately after the braiding, and the accuracy of the characteristic impedance value is set to ± 1 kW. It is to provide a high precision foam coaxial cable.

In a preferable aspect of the present invention, the following configuration is provided.

(1) The cross-sectional area of the insulator is compression molded to 90% of the cross-sectional area immediately after the winding.

(2) The bite rate of the said external conductor to the said insulator shall be 10% or more and less than 35%.

(3) The variation of the characteristic impedance value when the mechanical stress wound on the 5.0 mm diameter rod is added is ± 5 kPa or less.

(4) The precision of the outer diameter of the inner conductor is ± 4/1000 mm, the precision of the outer diameter of the insulator is ± 0.02 mm, and the precision of the outer diameter of the outer conductor is ± 2% of the center of the outer diameter. It is configured by.

(5) The porous tape body has a porosity of 6O% or more, wound around the inner conductor at a winding force of 0.7O kg / mm 2, a winding interval of 9 to 10 times the outer conductor outer diameter, and a winding angle of 75 to 80 degrees. It is composed.

(6) The outer conductor is braided with a two-layer plated copper wire having a tin alloy plating having a thickness of 0.2 to 0.5 μm to a silver plated copper wire having a thickness of 1 to 3 μm and having an outer diameter tolerance of ± 2/1000 mm. When the finishing thickness at the time of making a process is 1, the external shape is made into a round shape, and it is comprised by making the fluctuation | variation of the thickness into 5 to 10%.

(7) The outer conductor is braided with a nickel-plated copper wire having a thickness of 1 to 3 μm and a tin alloy plate having a thickness of 0.2 to 0.5 μm with a two-layer plating copper wire having an outer diameter tolerance of ± 2/1000 mm and braided. When the finishing thickness at the time of making a process is 1, the external shape is made into a round shape, and it is comprised by making the fluctuation | variation of the thickness into 5 to 10%.

(8) The said tin alloy plating consists of tin and copper, and the content rate of copper is 0.6 to 2.5%.

According to the high-precision foamed coaxial cable of the present invention, even if mechanical stress such as bending, torsion or slippage is added to the cable, the shape change of the insulator and the outer conductor is reduced, so that the appearance and the outer diameter can be maintained, and the variation of the characteristic impedance value is reduced. It is possible to provide high precision foamed coaxial cable.

1 is a schematic diagram showing the configuration of a high precision foamed coaxial cable of the present invention.

Fig. 2 is a schematic diagram showing the configuration of a portion of an insulated wire core of a high precision foamed coaxial cable according to the embodiment of the present invention.

3 is a view for explaining a method of winding up a porous tape body to an inner conductor and a molding method of an outer diameter of an insulator.

4 is a view for explaining a braiding method of a braided body with an insulated wire core and a shaping method for an outer conductor outer diameter.

[Description of the code]

1: internal conductor

2: insulator

3: outer conductor

4: outer shell

5: Insulated wire core

10: coaxial cable

15: Tape body supply part

21: porous tape

30a, 30b, 30c, 41, 42: guide die

31a, 31b, 43: forming dies

40: braiding device

44: braided wire

EMBODIMENT OF THE INVENTION Hereinafter, although embodiment of this invention is described with reference to drawings, this invention is not limited to these.

(Whole structure of high precision foam coaxial cable)

1 is a schematic diagram showing the configuration of a high-precision foam coaxial cable according to an embodiment of the present invention. The high precision foamed coaxial cable shown in FIG. 1 includes an insulator 2, an outer conductor 3 made of a braided body, and an outer sheath 4 in an inner conductor 1 having a plurality of element wires. It is comprised by covering with.

Fig. 2 is a schematic diagram showing the configuration of a portion of an insulated wire core of a high precision foamed coaxial cable according to the embodiment of the present invention. The insulated wire core 5 consists of the internal conductor 1 and the insulator 2, and is comprised by winding the porous tape body 21 which is an insulator to the internal conductor 1 specifically ,.

(Configuration of Each Part of High Precision Foamed Coaxial Cable)

The inner conductor 1 is constituted by a twisted line, each element wire can be moved, the twisted outer diameter is uniform, the variation thereof is small, and the shape is round. Specifically, for example, the inner conductor 1 (the conductor size is described in the example in which AWG # 26 is applied) is an interlocking wire coated with silver plating having a thickness of 1 to 3 µm, and the outer diameter thereof is 0.16 mm. Seven jointed conductors having an outer diameter of 2/1000 mm or less shall be used. The combined pitch can withstand flexibility even if mechanical stresses such as bending, torsion, and slippage are added, and is 15 times or less of the finish outer diameter for better adhesion with the wound insulator 2, and the precision of the outer diameter is 4 It is preferable to set it as / 1000 mm or less.

The insulator 2 is composed of a porous tape body 21 and is integrally integrated with the inner conductor 1 so that the relative dielectric constant thickness and outer diameter are small, the insulator 2 is round, and the insulator 2 itself is formed. It has a shape holding force for maintaining the shape.

When the outer diameter of the insulator 2 formed by winding the porous tape body 21 is 1, the outer shape of the insulator 2 is rounded by secondary molding, and the finished outer diameter is 3 to 5%. It reduces to 3.5 to 4.5% and sets it as 0.95 to 0.97, and makes the space | gap part with the internal conductor 1 uniform. By this tight integration, even if mechanical stress such as bending, torsion, or slippage is added, the variation in characteristic impedance value can be reduced.

In particular, when the cross-sectional area of the insulator 2 formed by winding the porous tape body 21 is set to 1, when the finish cross-sectional area of the insulator 2 is compressed to about 90% (0.9) by secondary molding, the flexibility of the insulated wire core is achieved. In addition, since the fluctuation | variation of a characteristic impedance value can be made small, it is preferable.

The porous tape body 21 has a low dielectric constant, a porosity of 60% or more, a precision of ± 5%, a thickness tolerance of ± 3 μm, and a compressive strain distortion of 0.6 to 0.8 when the compressive stress is within 0.24 to 0.28 kg. A plastic porous polytetrafluoroethylene (PTFE) tape body having a% of weight was applied, and the tape body having a width of 4.6 mm and a thickness of 0.09 mm was rolled up by 1/2, and the tape body having a width of 6.9 mm and a thickness of 0.09 mm was applied. It is preferable to configure by winding overlapping 1/2.

The winding angle of the tape body is 65 to 90 degrees, more preferably 70 to 85 degrees, more preferably 75 to 80 degrees, in order to further enhance the adhesion of the tape body. The winding interval is set to 7 to 12 times, more preferably 8 to 11 times, still more preferably 9 to 10 times the inner conductor outer diameter. The winding tension is 0.55 to 0.85 kg / mm 2, more preferably 0.6O to 0.80 kg / mm 2, more preferably 0.65 to 0.75 kg / mm 2, most preferably about 0.7O kg / mm 2, and the winding direction is initially It is preferable to set it as the opposite direction of the association direction of the internal conductor 1, and to make it the opposite direction to the first tape body winding direction in the next tape body winding. It is preferable that the variation of the thickness of the insulator 2 after winding is ± 0.01 mm, and the variation of the outer diameter is ± 0.02 mm.

The method of making the outer shape of the insulator 2 into a round shape, reducing the finished outer diameter, compressing the insulator cross-sectional area, and equalizing the voids between the inner conductor 1 and the insulator 2 may be carried out after winding of the tape body or described later. The insulating wire core 5 is pressed through a molding die for molding the outer diameter of the insulator to a predetermined outer diameter at the time of formation of the braided body layer to be formed by a molding process. This molding process is performed around the inner conductor 1 produced by the porous tape body 21 shown in FIGS. 2A and 2B and the voids a and b outside the insulator 2. In order to close the inner and outer conductors 1 of the insulator 2 by eliminating the defects, and to eliminate the unevenness of the inner and outer circumferences of the insulator 2 due to the winding, the thickness of the insulator becomes uniform by this treatment, and the variation of the outer diameter is eliminated. The outer shape is formed into a round cylindrical shape. For example, after making a tape body winding outer diameter 1.25 mm, it shape | molds by applying the shaping | molding dice of 1.20 mm diameter and 3.0 mm in length. The molding speed is set to 10 m / min, so that stable molding is achieved, and the adhesion between the insulator 2 and the inner conductor 1 is further strengthened to improve the shape retention of the insulator 2 itself.

The outer conductor 3 is composed of a braided body, and has good flexibility by sliding each element wire, has a close integration with the insulator 2 to reduce fluctuations in outer diameter and thickness, and makes the inner diameter circular, and at the same time the outer conductor itself Keep shape.

The outer conductor 3 is applied with a copper wire having an outer diameter of 0.05 to 0.10 mm, a plating layer of silver or nickel having a thickness of 1 to 3 µm, and a plating layer of a tin alloy having a thickness of 0.20 to 0.50 µm on its outer circumference. Then, the interlocking wire having a two-layer plating layer having an outer diameter tolerance of ± 2/1000 mm is applied to braid at a predetermined braid angle and braid density of 95% or more, and the braided outer diameter precision is formed to ± 2%.

The reason why the braid is applied to the outer conductor 3 is that damage is caused to the insulator 2 and the outer conductor 3 when bending, twisting, pressing, slipping or other mechanical stress is applied to the high-precision foam coaxial cable. Not to do that, and to give the cable flexibility.

In addition, applying the interlocking wire having a plating layer such as silver or nickel and two plating layers of a tin alloy plating layer to the braided wire has a low frictional resistance on the surface of the wire and improves slipperiness, thereby adding mechanical stress to the cable. In order that each element wire is easy to move at the time, the stress is dispersed and does not affect the insulator 2, and the shape of the braid is maintained to maintain the insulator 2 and prevent the buckling of the braid, while releasing internal stress. To prevent this.

The reason why the tin alloy plating layer is formed on the outer periphery of each element is to improve the slipperiness described above and to prevent whiskers. The contents of the tin alloy consist of tin and copper, and the content rate of copper is comprised from 0.6 to 2.5%. Moreover, the thing generally called lead-free soldering plating, such as containing 0.3 to 3.5% of silver and 1 to 10% of bismuth, is also applicable. It is effective to apply tin plating having a high conductivity and a small dynamic friction coefficient for the plating configuration of each element wire. However, in tin alone, copper diffuses into the tin plating layer when used under high temperature, and whiskers are generated and grown by diffusion stress. In order to prevent the short between the inner conductor 1 and the outer conductor 3 due to the promoted and grown whisker, and to prevent the whisker, to prevent diffusion of the internal copper, to add an additive to the tin, It is effective to reduce the internal stress caused by the heat treatment and to reduce the thickness of the plating. Here, the provision of a plating layer such as silver plating or nickel plating prevents the diffusion of copper, but the dynamic friction coefficient is large, so that the movement of the wires worsens and the flexibility of the cable is lost.

In order to improve the movement of the wires and to make the cable flexible, a copper wire in which a tin alloy hot-dip layer of 0.20 to 0.50 µm is further applied on the above-described plating layer. The thickness of the plating layer of the underlying silver, nickel, or the like is 1 to 3 mu m because the thickness of copper is required to be 1 mu m or more, but if too thick, the flexibility of the cable is adversely affected. If the thickness of the tin alloy plating is 0.2 μm or less, the underlying silver plating is exposed, and the flexibility is insufficient, and if it is 0.5 μm or more, whiskers are more likely to occur. Here, when the outline of the dynamic friction coefficient of each metal is described, silver is 1.30, copper is 0.90, and the tin alloy is 0.55. From this value, it is effective to apply tin alloy plating having a small dynamic friction coefficient to the wire of the braid. I can understand. In addition, the dynamic friction coefficient of each metal was calculated | required by the Bowden type low cost wear tester.

By shaping the outer diameter precision of the braid to ± 2%, the braid layer is throttled in the longitudinal direction, and the gap of the braid itself is eliminated, and the braid is in close contact with the insulator, and the gap between the braid and the insulator is also The inner diameter of the braided body is more close to the round cylindrical shape, the characteristic impedance value is constant, and the variation is less.

When the outer conductor 3 has the outer diameter of the outer conductor formed by braiding each conductive element wire as 1, the outer shape of the outer conductor is formed into a round shape by secondary molding, and the finish outer diameter thereof is 2 to 4%, more preferably. Preferably, the thickness is reduced by 2.5 to 3.5% to 0.96 to 0.98, the variation in the thickness is within ± 5%, and the variation in the thickness and the outer diameter is reduced. By this tight integration, even if mechanical stress such as bending, torsion, or slippage is added, the variation in characteristic impedance value can be reduced.

In particular, when the outer diameter is reduced, the ratio of the outer conductor 3 (braided wire) to the insulator 2 (hereinafter referred to as a "pinch rate") For example, the braided wire diameter is 0.1 mm and 0.02 mm to the insulator. When the bite ratio when pressed is set to 0.02 / 0.1 × 100% = 20%), 10% or more and less than 35%, more preferably 10% or more and 30% or less, still more preferably 15% or more and 25% or less It is preferable.

The angle of each conductive thin wire braiding the outer conductor 3 with respect to the outer diameter of the insulator 2 (the angle of the conductive thin wire along the outer circumference of the insulator 2) is better when the flexibility is taken into consideration. Since the fluctuation | variation of thickness, an outer diameter, etc. becomes large and the adhesiveness to an insulator worsens, it is preferable that a braid angle is 65-80 degree | times, More preferably, it is 70-75 degree | times.

The outer shape of the outer conductor 3 is rounded, the finished outer diameter is reduced, and the bit rate is set in a predetermined range. The outer diameter of the braided body layer is determined after braiding or during the shaping of the coaxial cable sheath 4 described later. A braided body-attached wire core is inserted into a molding die to be molded to an outer diameter and is formed by a molding process. As a result, the braid can be brought into close contact with the insulator 2, the fluctuations in the thickness, outer diameter, and the like can be reduced, and the voids in the braid can be reduced to increase the shape holding force of the outer conductor. For example, what made the outer diameter of an outer conductor 1.55 mm is press-molded by the shaping | molding die which has an inner diameter of 1.51 mm. By setting the molding speed to 1 to 2 m / min, the adhesion between the insulator 2 and the external conductor 3 is further strengthened, the thickness thereof is uniform, and the variation in the thickness can be within ± 5%.

The outer shell 4 is formed by extrusion molding of the FEP resin with its thickness being 0.5 or more times the thickness of the outer conductor 3 and the adhesion force with the braided layer being 20 g / mm 2 or more at 23 ° C. . Here, the reason for limiting the thickness is to maintain the shape of the braid when the mechanical stress is applied to the cable and to prevent buckling, and the reason for limiting the adhesion is that if the adhesion is less than 20 g / mm 2, the inside of the braid is This is because the release of stress cannot be suppressed, and as a result, the stability of the accuracy of the characteristic impedance value is insufficient. When adhesive force is 20 g / mm <2> or more, release | release of internal stress can be suppressed.

(Manufacturing method of high precision foam coaxial cable)

3 is a view for explaining a method of winding up a porous tape body to an inner conductor and a molding method of an outer diameter of an insulator. With reference to FIG. 3, the winding method of the porous tape body 21 and the shaping | molding method of the outer diameter of the insulator 2 are demonstrated.

The inner conductor 1, which is an associative conductor, is supplied to the first, second, and third guide dice 30a, 30b, 30c of the tape winding device, and the molding dies 31a, 31b from a supply unit (not shown). The supplied inner conductor 1 is rotated at a predetermined rotational speed in the direction of the arrow Y1. This rotating inner conductor 1 is sent in the direction of arrow Y2 at a predetermined speed, and after passing through the first guide die 30a, the tape body supply part 15 in front of the second die 30b. ), The porous tape body 21 is wound up. This makes the porous tape 21 21 with respect to the inner conductor 1 at an angle of 80 ° and a tape tension of 300 g, and rotates in the direction of arrow Y1 of the inner conductor 1 itself to the outer periphery of the inner conductor 1. It winds up by 1/2 superimposing and winding up a tape body once again on the outer periphery.

Thus, the tape winding body which wound the porous tape body 21 and passed through the 2nd dice | dies 30b is the 1st and 2nd shaping | molding dice 31a and 31b arrange | positioned between the 2nd and 3rd guide dice | dies 30b and 30c. Penetrated in). Here, the fluctuation | variation of an outer diameter is shape | molded as +/- 2% in the 1st shaping | molding die 31a of 1.13 mm of internal diameters and 3.0 mm of internal diameter lengths. The porous tape body 21 which has passed through the first molding die 31a is then inserted into the second molding die 31b, where a predetermined outer diameter and its tolerance are obtained in the dimensions of 1.12 mm inner diameter and 3.00 mm inner length. Is molded into. By the above molding process, the outer diameter of the porous tape body 21 becomes a round cylindrical body shape, and adhesion with the conductor 1 improves, and the thickness nonuniformity, the unevenness | corrugation of an outer diameter, the fluctuation of an outer diameter, etc. are reduced. When shaping | molding the porous tape body 21 shape | molded by the shaping | molding dice 31a and 31b more smoothly, shaping | molding dice | dies 31a and 31b etc. can also be rotated by predetermined rotation speed. In addition, when winding up a tape and baking a tape body simultaneously, you may heat shaping | molding dice 31a and 31b to baking temperature.

4 is a view for explaining a braiding method of a braided body with an insulated wire core and a shaping method for an outer conductor outer diameter. 4, the outline | summary of the braiding method of a braided body, and the shaping | molding method of the outer diameter of the outer conductor 3 is demonstrated.

The tape winding insulation wire core 5 wound around the outer conductor 1 of the inner conductor 1 and formed with a predetermined outer diameter and a predetermined outer diameter precision is supplied to the braiding device 40, and the first, It penetrates into the 2nd guide dice 41 and 42 and the shaping | molding die 43. As shown in FIG.

In addition to guiding the insulated wire core 5, the first guide die 41 forms the insulated wire core 5 before braiding with a predetermined outer diameter and a predetermined outer diameter precision. The insulated wire core 5 which passed the 1st guide die 41 has a some braided element wire 44, and the braided element wire 44 is rotated by the rotation of the braiding apparatus 40 which rotates in an opposite direction alternately. It is incorporated and braided just before the second guide die 42. The second guide die 42 guides the braid 3, and also forms the outer circumference of the braid 3.

The braid 3 having passed through the second guide die (braiding die) 42 is inserted into the shaping die 43 having an inner diameter of 1.50 mm in inner diameter and 3.00 mm in inner diameter, and is formed by the shaping die 43. The braid 3 is molded. By this molding, since the braid 3 is stretched and throttled in its longitudinal direction, the void portion of the braid 3 itself is eliminated, and the braid 3 is in close contact with the insulator 2 and the braid 3 ), The gap between the insulator 2 is eliminated, the inner diameter of the braid body 3 becomes closer to the value of the outer diameter of the insulator 2, and the nonuniformity of the thickness of the braid body 3, the unevenness of the outer diameter, the fluctuation of the outer diameter, etc. It is reduced, so it is close to the round cylinder shape, and the uniformity and characteristic variation of the characteristic impedance value are reduced.

(First embodiment)

By the method described in embodiment of this invention, the insulation wire core 5 was shape | molded by changing the reduction rate (compression rate) of the outer diameter of the insulator 2, and the variation of the outer diameter of each insulation wire core 5 was investigated. The inner conductor 1 is a copper wire with silver plating having a thickness of 1 μm and an outer diameter of 0.16 mm, and seven joint conductors were used in which the outer diameter precision was 2/1000 mm or less. The porous tape body 21 used the thing of 80% of porosity, the winding angle of the tape body was 80 degree, and the winding tension was 0.7Okg / mm <2>. The results are shown in Table 1.

TABLE 1

Relationship between outer diameter compressibility of insulation and fluctuation of outer core diameter

Insulator Outer Diameter Compression Ratio (%) Variation of Insulation Core Outer Diameter 0 0.008 4 0.004 10 0.006

When the compressibility of the outer diameter of the insulator 2 was increased (10%), the tensile force at the time of passing the forming die at the time of forming the outer shape and the outer diameter was increased, and the insulation wire core 5 was stretched and further disconnected. The best results were obtained when the outer diameter of the insulator 2 was molded by compression of 3 to 5%, in particular 4%.

(2nd Example)

By the method described in the embodiment of the present invention, the bit rate of the braided body to the insulator 2 (insulation core 5) is changed to shape the coaxial cable 10, and the braid of each coaxial cable 10 is formed. The variation of the outer diameter and characteristic impedance values was investigated. The results are shown in Table 2. The braided wire used for a braided body is the copper wire with a 2-layer plating which gave the silver plating copper wire of 1 micrometer in thickness, and the tin alloy (0.75% copper) plating of 0.5 micrometer in thickness. The variation of the characteristic impedance value was measured by applying the TDR measuring method, and the standard deviation was calculated.

[Table 2]

Relationship between the bite rate of the braided body and the fluctuation of braided outer diameter and characteristic impedance

% Bite of braid Variation of Braided Outer Diameter Variation of characteristic impedance 5 0.008 0.465 15 0.005 0.342 25 0.003 0.199 35 0.004 0.250

By increasing the bite rate of the braid, the insulator and the braid were integrated, the roundness of the braid was improved, and the fluctuation of the characteristic impedance value could be reduced. However, when the bit rate is set to 35% or more, it is preferable that the bit rate is set to less than 35% because the frictional resistance between the molding die and the braid is large, causing disconnection, and impairing the flexibility of the cable. According to the present invention, the accuracy of the characteristic impedance value can be set to ± 1 Hz, ± 0.5 Hz, and ± 0.35 Hz.

(Third Embodiment)

By the method described in the embodiment of the present invention, the coaxial cable 10 is formed by varying the bite rate of the braided body to the insulator 2 (insulation core 5) and the type of plating of the braided element wires. The change of the characteristic impedance value (bending test) and the flexibility (flexibility test) of the coaxial cable 10 when the mandrel rod of the outer diameter 5φ of the coaxial cable 10 was wound 5 times were investigated. The results are shown in Table 3. The braided wire used for the braided body used the 1-micrometer-thick silver-plated copper wire and the 1-micrometer-thick silver plating copper wire with the 2-layer plating copper wire with 0.5-micrometer-thick tin alloy (0.75% copper) plating.

The bending test measures the characteristic impedance value (A) of the cable cut to 500 mm, wound about 200 mm of the cable in the mandrel rod having a diameter of 5.0 mm five times with a tension of 200 g, and the characteristic impedance in that state. The value B was measured and the change of the characteristic impedance value was calculated | required from (A)-(B). This is an alternative test that adds mechanical stress, such as bending and twisting, that the cable would normally receive, and shows a change in characteristic impedance.

In the flexibility test, a 72 mm mark was applied to the center of the cable having a length of 150 mm, and two test pieces left for 2 hours at a temperature of 23 ± 2 ° C. and a relative humidity of 65% or less were compressed to both ends by 40 mm. Get the value of the time force. The result is represented by the following symbols.

◎: flexibility vs. ○: in flexibility, △: flexible flexibility.

TABLE 3

The relationship between the bite rate of the braided body, the type of plating of the braided wire and the characteristic impedance change, and the flexibility of the cable

 % Bite of braid Change of characteristic impedance  Cable flexibility Silver plating only 2-layer plating of Ag and Sn alloys 5 12.10 6.94 ◎ 15 9.60 5.31 ○ 25 6.90 4.03 ○ 35 6.21 3.92 △

By applying two-layer plating of Ag and Sn alloys (Cu 0.75%) to the braided wire, the frictional resistance of the wire surface is reduced, and the wires of the braid are moved when mechanical stress such as bending, torsion or slippage is applied to the cable. It is easy to disperse | distribute stress, and the shape of a braid body can be maintained and a change of characteristic impedance value can be made small. According to the present invention, even when the above-described mechanical stress is added, the variation of the characteristic impedance value can be set to ± 5 kPa or less, ± 4.5 kPa or less, and ± 4 kPa or less.

Further, from Tables 2 and 3, when two-layer plating is used for the braided wire material and the bit rate of the braided wire is 15 to 25%, the variation in the characteristic impedance value is small, the flexibility of the cable, the bending, High precision foamed coaxial cable with a small change in characteristic impedance value was obtained for mechanical stress such as torsion and slipping.

It is applicable to the use as a coaxial cable and a coaxial cord in industrial equipment which requires the high speed of transmission speed and the improvement of transmission precision, such as an information communication apparatus and the test and inspection apparatus used for the information communication apparatus.

Claims (9)

High-precision foam consisting of an inner conductor formed by associating a conductor, an insulator formed by winding a porous tape body around the outer circumference of the inner conductor, and an outer conductor formed by braiding a plurality of conductive fine wires on the outer circumference of the insulator In coaxial cable, The outer shape of the insulator is round and the outer diameter of the insulator is molded at a reduction ratio of 3 to 5% with respect to the outer diameter of the insulator immediately after the winding, and the outer conductor is rounded and the outer diameter of the outer conductor is rounded. A high-precision foamed coaxial cable characterized by molding at a reduction ratio of 2 to 4% with respect to the outer diameter of the outer conductor immediately after the braiding, and setting the accuracy of the characteristic impedance value to ± 1 kPa. The high precision foam coaxial cable according to claim 1, wherein the cross-sectional area of the insulator is compression molded to 90% of the cross-sectional area immediately after the winding. The high accuracy foam coaxial cable according to claim 1, wherein the bite rate of the external conductor to the insulator is set to 10% or more and less than 35%. The high-precision foam coaxial cable according to claim 1, wherein a variation in characteristic impedance value when a mechanical stress wound on a 5.0 mm diameter rod is added is ± 5 kPa or less. The precision of the outer diameter of the inner conductor is ± 4/1000 mm, the precision of the outer diameter of the insulator is ± 0.02 mm, and the precision of the outer diameter of the outer conductor is ± It is comprised as 2%, The high precision foam coaxial cable characterized by the above-mentioned. The porous tape body according to claim 1, wherein the porous tape body has a porosity of 6O% or more, a winding force of 0.7O kg / mm 2, a winding interval of 9 to 10 times the inner conductor outer diameter, and a winding angle of 75 to 80 degrees. The high-precision foam coaxial cable, characterized by being wound on. 2. The outer conductor of claim 1 is braided with a two-layer plating copper wire having an outer diameter tolerance of ± 2/1000 mm by applying tin alloy plating having a thickness of 0.2 to 0.5 µm to a silver plating copper wire having a thickness of 1 to 3 µm. And when the finishing thickness at the time of a braiding process is set to 1, the outer shape is made into round shape, and the fluctuation | variation of the thickness is comprised by 5 to 10%, The high precision foamed coaxial cable characterized by the above-mentioned. 2. The outer conductor of claim 1 is braided with a nickel plated copper wire having a thickness of 1 to 3 μm and a tin alloy plating having a thickness of 0.2 to 0.5 μm with a two-layer plated copper wire having an outer diameter tolerance of ± 2/1000 mm. And when the finishing thickness at the time of a braiding process is set to 1, the outer form is made into round shape, and the fluctuation | variation of the thickness is comprised by 5 to 10%, The high precision foamed coaxial cable characterized by the above-mentioned. The high-precision foam coaxial cable according to claim 7 or 8, wherein the tin alloy plating is made of tin and copper, and the content of copper is 0.6 to 2.5%.

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