JP3749875B2 - Manufacturing method of high precision foamed coaxial cable - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a high-precision foamed coaxial cable in which an insulator on the outer periphery of an inner conductor is formed of a porous tape body, and an outer conductor is formed of a braided body of a conductive thin wire. The present invention relates to a method for manufacturing a high-precision foamed coaxial cable in which the thickness of an insulator and an outer conductor and fluctuations in the outer diameter are reduced in order to make the characteristic impedance value ± 1Ω, and these are formed into a perfect circle.
[0002]
[Prior art]
With the progress of the advanced information society in recent years, there is an increasing demand for an increase in transmission speed and an improvement in transmission accuracy of information communication devices and semiconductor element test / inspection devices applied to the devices. For this reason, even in the case of a coaxial cable and a coaxial cord that are applied to the devices and apparatuses, an increase in transmission speed and an improvement in transmission accuracy are required.
[0003]
Here, typical electrical characteristics required for the coaxial cable are described as follows.
[0004]
Propagation delay time (Td) = √ε / 0.3 (nS / m)
Relative transmission speed (V) = 100 / √ε (%)
Characteristic impedance (Zo) = 60 / √ε · LnD / d (Ω)
Capacitance (C) = 55.63ε / LnD / d (PF / m)
Where ε is the dielectric constant of the insulator, D is the outer diameter of the insulator (the inner diameter of the outer conductor), and d is the outer diameter of the conductor (the outer diameter of the inner conductor).
[0005]
Therefore, the transmission characteristics of the coaxial cable are related to the relative dielectric constant of the insulator, the outer diameter of the inner conductor and the insulator. The smaller the value of the relative dielectric constant, the better the transmission characteristics, and the inner conductor. As for the outer diameter of the insulator, it can be understood that the ratio and variation are largely involved. In particular, with respect to the characteristic impedance and capacitance, the relative dielectric constant of the insulator is small and its variation is small, and there are few variations such as the outer diameter of the inner conductor and the insulator (inner diameter of the shield layer). It can be understood that it is ideal to form the shape of a more perfect circular cylinder.
[0006]
[Problems to be solved by the invention]
However, the conventional coaxial cable has the following problems (1) to (3).
[0007]
(1) The inner conductor applied to the coaxial cable is an AWG 20-30 silver-plated annealed copper wire or a twisted conductor obtained by twisting them, but the outer diameter tolerance of the silver-plated annealed copper wire is ± 3/1000 mm. Yes, in the case of twisted conductors, for example, when these seven twists are twisted, the tolerance of the twisted outer diameter becomes ± 3 × 3/1000 mm. For this reason, if the cable is made within the tolerance of the outer diameter of those, it becomes a large variation factor in the above-mentioned characteristic impedance, capacitance and the like. This effect increases as the inner conductor becomes thinner.
[0008]
(2) The foam insulator applied to the coaxial cable is designed to reduce the propagation delay time of the cable as much as possible and increase the transmission speed. At present, the porosity (foaming rate) is set to 60% or more. By providing a large number of gaps, the dielectric constant (ε) of the insulator is set to 1.4 or less, thereby shortening the transmission time, reducing the attenuation, and the like. As an insulator material having a porosity of 60% or more and a relative dielectric constant of 1.4 or less, a porous tape body of polytetrafluoroethylene (PTFE) (Japanese Patent Publication Nos. 42-13560 and 51-18991) In the outer circumference of the inner conductor and is fired during or after winding. As another porous tape body, a polyethylene tape body having a weight average molecular weight of 5 million or more is applied. Is applied (Japanese Patent Application No. 2000-110443).
[0009]
However, these insulator layers have large variations in thickness and porosity due to the properties of the porous tape body, and there is a strong demand for improvement in the stability of the transmission characteristics of the coaxial cable. In particular, a coaxial cable with an inner conductor size of AWG24 or larger and a characteristic impedance value of 50Ω is stabilized by eliminating variations in transmission characteristics due to variations in thickness, outer diameter, porosity, firing, etc. It is a big obstacle on the top.
[0010]
In addition, since the insulator layer is formed by laminating and winding a porous tape body on the outer periphery of the inner conductor, an irregularity of the outer shape due to the gap portion and the overlap occurs in the overlapping portion of the tape body on the outer periphery of the conductor, and the relative dielectric constant In addition, the variation in the outer diameter becomes extremely large.
[0011]
In addition, since this insulator layer is formed by winding a porous tape body having a very low mechanical strength, in order to eliminate elongation and breakage during winding of the tape body itself, and to extend and break the ultrafine internal conductor. In order to eliminate this, the tension of the tape body needs to be extremely small. For this reason, the insulator after winding is further increased in unevenness in outer shape and variation in outer diameter, is very weak in contact with the inner conductor, and is further expanded in variation in relative permittivity and outer diameter.
[0012]
Furthermore, this insulator layer has a relatively low dielectric constant mainly for the purpose of increasing the transmission speed by minimizing the propagation delay time of the cable, so that the mechanical strength, that is, the bending and twisting that the coaxial cable undergoes. However, it still has the disadvantage that it is difficult to maintain the structural dimensions of the coaxial cable due to mechanical stress such as pressing and sliding. The biggest drawback is that it is difficult to maintain the insulator outer diameter at a predetermined outer diameter to eliminate the variation and to form the insulator in a cylindrical shape.
[0013]
(3) The outer conductor that is largely involved in the transmission characteristics of the coaxial cable is a conventional type of coaxial cable in which a plastic tape body having a metal layer such as copper is wound around the outer periphery of the insulator or vertically attached. Or a braided body braided with silver-plated annealed copper wire or tin-plated annealed copper wire with an outer diameter tolerance of ± 3/1000 mm according to JIS standards, and further, the above tape body and the above braided body A combination of the above and the like has been applied.
[0014]
However, when the tape body is wound or vertically attached, the flexibility of the cable is insufficient, and the external conductor is easily broken due to mechanical stress such as bending or twisting applied to the cable. The function cannot be performed. In the braided body of silver-plated annealed copper wire, since the sliding property of silver is small, the frictional force due to the contact between the silver-plated annealed copper wires increases, and each braided body is configured by mechanical stress such as bending and twisting applied to the cable. There is no movement of the wire, the cable lacks flexibility, the insulation layer is deformed, the characteristic impedance value fluctuates, the influence of mechanical stress cannot be reduced, the cable life is shortened, etc. Built-in topic.
[0015]
In a braided body of tin-plated annealed copper wire, when used at a high temperature (80 ° C. or higher), copper diffuses into the tin-plated layer and promotes the generation and growth of tin whiskers by diffusion stress. When this whisker grows greatly, it may break through the ultrathin insulator and cause a short circuit with the internal conductor. Further, as described in the description of the insulator in (2) above, each of the above outer conductors is formed on the outer periphery of the insulator with the unevenness of the outer shape of the insulator and the variation of the outer diameter. The inside and outside of the conductor was uneven, and the variation in outer diameter remained large, and there were many gaps between the outer conductor and the insulator layer, leaving a factor of variation in the relative permittivity.
[0016]
The present invention has been made in view of the above point, and secondary molding of a high-foam insulator of a coaxial cable having a high-foam insulator (foaming degree of 60% or more) to which a porous tape body is applied and an outer conductor. In addition, the thickness and outer diameter can be made uniform and the outer shape can be made into a perfect circle, improving the accuracy of the characteristic impedance value between the inner conductor and the outer conductor, and stabilizing the secondary molding process. An object of the present invention is to provide a method for producing a highly accurate foamed coaxial cable.
[0017]
[Means for Solving the Problems]
In order to solve the above-described problems, a method for manufacturing a high-precision foamed coaxial cable according to the present invention includes an inner conductor, a foamed insulator formed on the outer periphery of the inner conductor, and an external formed on the outer periphery of the foamed insulator. In a method of manufacturing a high-precision foamed coaxial cable having a conductor, a winding step of forming a foamed insulator by winding a porous tape body having a porosity of 60% or more around the inner conductor supplied from a supply unit; , The foam insulation formed in the winding step, By a primary molding step of inserting and molding a primary molding die having a predetermined inner diameter and a secondary molding step of inserting and molding a secondary molding die having a predetermined inner diameter, An insulator molding process in which a molding die having a predetermined inner diameter is inserted to form a predetermined outer diameter and a perfect circle, and a plurality of conductive thin wires are braided on the outer periphery of the foamed insulator formed in the insulator molding process. A braiding step for forming the outer conductor, and an outer conductor forming step for forming the outer conductor formed in the braiding step into an outer conductor forming die having a predetermined inner diameter and forming a predetermined outer diameter and a perfect circle. It is characterized by that.
[0018]
According to this configuration, the thickness and the outer diameter of the foamed insulator formed by winding the porous tape body around the inner conductor outer periphery and the outer conductor formed of the braided body around the outer periphery of the foamed insulator are made uniform and rounded. It is possible to improve the close integration of the inner conductor and the foamed insulator, and the foamed insulator and the outer conductor.
[0019]
That is, The insulator forming step is characterized by comprising a primary forming step of forming through a primary forming die having a predetermined inner diameter and a secondary forming step of forming through a secondary forming die having a predetermined inner diameter. .
[0020]
According to this configuration, Foam insulator formed by winding a porous tape body having a porosity of 60% or more When forming with a forming die, it is possible to perform stable molding without damaging, stretching, or breaking the foamed insulation core.
[0021]
Further, it has an outer shape holding layer step of forming an extremely thin outer shape holding layer by winding on the outer periphery of the foamed insulator formed into a predetermined outer shape and a perfect circle shape by the insulator forming step. .
[0022]
According to this configuration, it is possible to continuously maintain the outer diameter and outer shape of the foamed insulator formed in a perfect circular shape with a predetermined outer diameter.
[0023]
The outer conductor forming step includes a primary forming step of inserting and forming the outer conductor into a primary forming die having a predetermined inner diameter, and a secondary forming step of inserting and forming a secondary forming die having a predetermined inner diameter. It is characterized by consisting of.
[0024]
According to this configuration, the outer conductor is brought into close contact with the foamed insulator, the thickness and outer diameter thereof are uniformized, and disconnection, deformation, elongation, damage, etc. are eliminated in the outer conductor molding process for making the outer shape a perfect circle. Stabilize and thereby improve productivity.
[0025]
The outer conductor forming step is characterized in that the outer conductor is formed by rotating the outer conductor forming die at a predetermined rotational speed.
[0026]
According to this configuration, the outer conductor molding in the outer conductor molding process can be stabilized, and disconnection, deformation, elongation, damage, etc. can be eliminated.
[0027]
The outer conductor forming step is characterized in that ultrasonic vibration is applied to the outer conductor forming die to give a predetermined vibration in the outer diameter direction of the outer conductor.
[0028]
According to this configuration, the outer conductor molding in the outer conductor molding process can be stabilized, and disconnection, deformation, elongation, damage, etc. can be eliminated.
[0029]
Further, the outer conductor forming step is provided after the braiding step, or is provided alone immediately before the outer sheath forming step of the outer conductor formed on the outer periphery of the outer conductor, or after the braiding step and the outer sheath formation. It is characterized in that it is provided either before or after the process.
[0030]
According to this structure, the shaping | molding precision of an outer conductor shaping | molding can be improved more.
[0031]
Further, in the outer conductor molding step, when the frictional force between the outer conductor inserted through the primary molding die and the primary molding die is a predetermined value or more, the secondary molding die is rotated at a predetermined rotational speed. It is characterized by.
[0032]
According to this configuration, the outer conductor can be more stably molded in the outer conductor molding step, and the molding accuracy can be further improved.
[0033]
Further, in the outer conductor forming step, when a frictional force between the outer conductor inserted through the primary forming die and the primary forming die is a predetermined value or more, ultrasonic vibration is applied to the secondary forming die. It is characterized by.
[0034]
According to this configuration, the outer conductor can be more stably molded in the outer conductor molding step, and the molding accuracy can be further improved.
[0035]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0036]
(Embodiment)
FIG. 1 is a process diagram for explaining a method of manufacturing a high-precision foamed coaxial cable according to an embodiment of the present invention.
[0037]
FIG. 2 shows the configuration of the high-precision foamed coaxial cable formed in the manufacturing process of FIG. This high-precision foamed coaxial cable is configured by covering an inner conductor 1 having a plurality of strands with a foam insulator 2, an outer conductor 3 made of a braided body, and a jacket 4 in this order. However, the outer conductor 3 is also referred to as a braided body 3 in the following description.
[0038]
Further, the manufacturing process of the high-precision foamed coaxial cable shown in FIG. 1 includes three processes: an insulator forming process P1, an outer conductor (braided body) forming process P11, and an outer jacket forming process P21. The insulator forming process P1 includes an internal conductor supplying process P2, a tape winding process P3, an insulator forming process P4, and a winding process P5. The outer conductor (braided body) forming step P11 includes an insulated wire core supplying step P12, an insulator forming step P13, a braiding step P14, a braided body forming step P15, and a winding step P16. The jacket forming process P21 includes a braided wire core supplying process P22, a braided body forming process P23, a jacket covering process P24, and a winding process P25.
[0039]
The feature of the present embodiment lies in the insulator forming step P1 and the outer conductor (braided body) forming step P11.
[0040]
The insulator forming step P4 in the insulator forming step P1 and the insulator forming step P13 in the outer conductor (braided body) forming step P11 have the same contents, and the outer conductor (braided body) forming step P11 is the same. The braid body forming step P15 and the braid body forming step P23 of the outer jacket forming step P21 have the same contents. Therefore, the insulator forming steps P4 and P13 and the braided body forming steps P15 and P23 may be performed independently in one of the steps, or may be performed in duplicate in both steps. If it is carried out repeatedly, the irregularities of the outer diameter of the insulator and the braided body, the fluctuation accuracy of the outer diameter, the accuracy of rounding are improved, and the molding operation is also stabilized.
[0041]
Next, the insulator formation process P1 will be described with reference to FIG.
[0042]
First, in the internal conductor supply step P2, as shown in FIG. 3, the twisted conductor (internal conductor) 1 is replaced with the first, second, and third guide dies 30a, 30b, and 30c of the tape winding device, and the forming die. 31a and 31b are supplied from a supply unit (not shown).
[0043]
The supplied conductor 1 is rotated at a predetermined rotational speed in the direction of arrow Y1 in the tape winding process P3. The rotating conductor 1 is sent in the direction of the arrow Y2 at a predetermined speed, so that the porosity supplied from the tape body supply unit 15 after passing through the first guide die 30a and before the second die 30b. 60% or more of the porous tape body 21 is wound. This is because the porous tape body 21 is wound around the outer periphery of the conductor 1 in a 1/2 layer by rotating the conductor 1 itself in an arrow Y1 direction at an angle of 80 ° and a tape tension of 300 g with respect to the conductor 1, The tape body is once again wound around the outer periphery.
[0044]
The porous tape body 21 wound in this way passes through the second die 30b in the insulator forming step P4, and the tape wound body 10 formed by this passage passes through the second and third guide dies 30b. , 30c are inserted into first and second molding dies 31a, 31b. At the time of this insertion, the foamed insulator 2 is formed by the drawing force due to the inner diameters of the molding dies 31a and 31b. However, the first molding die 31a has an inner diameter of 1.13 mm and a die length of 3.0 mm, and the second molding die 31b has an inner diameter of 1.12 mm and a die length of 3.0 mm, and the passing speed of the tape roll 10 is 10 m / min.
[0045]
The outer diameter of the foamed insulator 2 formed in this way is a perfect circular cylinder, and the contact with the conductor 1 is improved, and uneven thickness, unevenness of the outer diameter, variation in outer diameter, etc. are reduced. The When the tape winding body 10 is formed more smoothly by the porous tape body 21 formed by the forming dies 31a and 31b, the forming dies 31a and 31b and the like can be rotated while rotating at a predetermined rotational speed. . Furthermore, when performing tape winding and baking of a tape body simultaneously, you may heat the shaping | molding dies 31a and 31b to baking temperature. The foamed insulator 2 is wound up in the winding process P5.
[0046]
Next, the outer conductor (braided body) forming step P11 will be described with reference to FIG.
[0047]
First, in the insulated core supply step P12, the tape tape 21 is formed with a predetermined outer diameter and a predetermined outer diameter accuracy by winding the porous tape body 21 around the conductor 1 in the insulator forming step P1. The insulated wire core 10 is supplied to the braiding device 40 and is inserted into the first and second guide dies 41 and 42 of the braiding device 40 and the forming die 43.
[0048]
In the insulator forming step P13, the insulating wire core 10 is guided with a predetermined outer diameter and a predetermined outer diameter accuracy by the first guide die 41 that also serves as a forming die while guiding the insulating wire core 10. The
[0049]
In the braiding step P14, the insulated wire core 10 that has passed through the first guide die 41 has a plurality of braiding strands 44 and the braiding strands 44 are rotated by the braiding device 40 that rotates alternately in the opposite direction. It is knitted and braided immediately before the second guide die 42.
[0050]
After this braiding, in the braided body forming step P15, the outer periphery is formed by being inserted through the second guide die 42 that also serves as a forming die, and the braided body 3 is formed by being further inserted into the forming die 43. Is done. However, the forming die 43 has an inner diameter of 1.5 mm and a die length of 3.0 mm. Only when the braiding device 40 is in operation, the forming die 43 is rotated by a motor (not shown) at a rotational speed of about 10 times the braiding speed. It shall be molded.
[0051]
Further, when the braided body 3 is molded by the molding die 43, the braided body 3 is pulled and drawn in the length direction thereof, so that the gap of the braided body 3 itself disappears and the braided body 3 becomes more of the foamed insulator 2. The gap between the braided body 3 and the foamed insulator 2 disappears and the inner diameter of the braided body 3 becomes closer to the value of the outer diameter of the foamed insulator 2, the thickness of the braided body 3 is uneven, the irregularities of the outer diameter, The variation in outer diameter and the like are reduced to approach the shape of a perfect circular cylinder, and the characteristic impedance value becomes constant and its fluctuation is reduced. The braided body (braided body core) 3 is wound in the winding process P16.
[0052]
In addition, in the braided body forming step P15, as shown in FIG. 5, ultrasonic vibration may be applied to the forming die 43 of the braided body 3 so that predetermined vibration is applied in the outer diameter direction of the braided body 3 for forming. .
[0053]
That is, when forming the braided body 3 by inserting the braided body 10a braided with the braiding element wire 44, which is a conductive thin wire, into the forming die 43 to form the braided body 3, the ultrasonic oscillating apparatus 51 The outer conductor is formed by applying ultrasonic vibration having a frequency of 20 to 45 KHz, an amplitude of 5 μm, and an output of 200 to 700 W. By this molding, the braided body 3 is tightly integrated with the foamed insulator 2, the thickness of the braided body 3 is made uniform, and the outer diameter unevenness is eliminated and the braided body 3 is molded into a perfect circle.
[0054]
Here, the outlet diameter 52 of the forming die 43 is 1.50 mm, the inlet diameter 53 of the die 43 is 1.7 mm, and the length of the outlet diameter 52 portion of the die 43 is 3.0 mm, and is made of a stainless steel material or the like. A resonance disk 55 that applies radial vibration to the die 43 is provided on the outer surface of the molding die 43, and a vibrator 56 that vibrates the resonance disk 55 is provided on the outer surface of the resonance disk 55. It has been.
[0055]
The vibrator 56 is configured to vibrate by the ultrasonic oscillation device 51 and transmit only when the braiding device 40 is in operation. The ultrasonic oscillation device 51 that oscillates only when the braiding device 40 is operated by the rotation detection device 57 of the braiding device vibrates the forming die 43 by converting electrical vibration into mechanical vibration through the vibrator 56.
[0056]
The forming die 43 forms the braided body 3 in contact with the die 43 by vibration and the die hole diameter under the above-described vibration conditions. Where the outer diameter of the braided body 3 is uneven and the fluctuation of the outer diameter is large, the frictional force between the braided body 3 and the die 43 is reduced by vibration or eliminated to eliminate the disconnection and scratches of the braided body 3, and further foam insulation. The body 2 and the internal conductor 1 are molded without disconnection, elongation, damage or the like.
[0057]
In addition, the braided body forming step P15 is provided after the braided step P14 in the above description. Alternatively, the braided body forming step P15 is provided alone immediately before the outer cover forming step P21, or after the braided step P14 and the outer cover forming step. You may provide in both immediately before P21.
[0058]
In the braid body forming step P15, the braid body 3 may be more stably formed by the control configuration shown in FIG.
[0059]
First, the braided body core is inserted into the second guide die 42 that also serves as a forming die, and the contact friction force (contact pressure) between the die 42 and the braided body core generated by this insertion is detected by the frictional force detector 61. Detect with. The detected frictional force is compared with a preset tensile strength (elongation) of the braided body core by the frictional force comparison unit 62. As a result, when the contact friction force is large, the motor control unit 63 rotates the motor 64 for rotating the forming die 43. Thus, when the forming die 43 rotates, the frictional force (pressure) applied to the braided body core when the forming die 43 forms the braided body core decreases, and stable outer conductor molding can be performed.
[0060]
In actual implementation, the diameter of the second guide die 42 is 1.60 mm, the diameter of the forming die 43 is 1.50 mm, and the forming die 43 is rotated at a rotational speed that is about 10 times the braiding speed. The contact frictional force between the forming die and the braided body core is a value at which the braided body is deformed. 100 gf / mm ² When it became above, it was rotated.
[0061]
Furthermore, in the braid body forming step P15, the braid body 3 may be more stably formed by the control configuration shown in FIG.
[0062]
As described with reference to FIG. 6 above, when the contact friction force and the tensile force are compared by the friction force comparison unit 62 and the contact friction force is large, the ultrasonic oscillation device is connected via the ultrasonic oscillation control unit 71. 51 is transmitted, the vibration is transmitted to the forming die 43 via the resonance disk 55 and the vibrator 56, and the braided body core is formed by the vibration of the forming die 43. Due to the ultrasonic vibration of the forming die 43, the contact frictional force applied to the braided wire core decreases and decreases, and the frictional force (pressure) applied to the braided wire core when forming the braided wire core with the forming die 43 is reduced. As a result, the outer conductor can be stably molded.
[0063]
In actual implementation, the diameter of the second guide die 42 is 1.60 mm, the diameter of the molding die 43 is 1.50 mm, and the molding die 43 is vibrated in the same manner as described above, and the second guide die 42 and the braided body core The contact friction force of 100 gf / mm is a value at which the braided body 3 is deformed. ² When it became above, it was vibrated.
[0064]
After performing the insulator forming step P1 and the outer conductor (braided body) forming step P11, the outer coat forming step P21 is performed, so that as shown in FIG. A foamed insulator 2 formed by winding a porous tape body around the outer periphery of the conductor 1, an external conductor 3 formed of a braid provided on the outer periphery of the foamed insulator 2, and an external provided on the outer periphery of the external conductor 3 A high-precision foamed coaxial cable 80 composed of the cover 4 is formed.
[0065]
In addition, an outer diameter holding layer 86 may be formed on the outer periphery of the foamed insulator 2 as in the high-precision foamed coaxial cable 85 shown in FIG. The outer diameter holding layer 86 is formed by holding a plastic tape body on the outer periphery of the foamed insulator 2 with a winding angle of 80 degrees without overlapping. This outer diameter holding layer 86 is for preventing the outer diameter of the foamed insulator 2 from returning to the original with the passage of time after the outer diameter of the foamed insulator 2 is molded within ± 1%, for example. A polyethylene terephthalate tape having a thickness of 0.025 mm and a width of 7.5 mm can be applied.
[0066]
Next, FIG. 9 shows the fluctuation of the insulator outer diameter (mm) when the foamed insulator is formed by applying the insulator formation step P1 described above, and shows the fluctuation of the insulator outer diameter (mm) when not applied. As shown in FIG. 10, both were compared.
[0067]
As a result, it has been clarified that when the foamed insulator is molded with a molding die, the outer diameter thereof becomes constant and becomes a perfect circle, and the variation thereof is small. The outer diameter was measured using a laser type outer diameter measuring instrument (manufactured by Takikawa Engineering Co., Ltd.) at intervals of 100 mm in the length direction.
[0068]
Moreover, the fluctuation | variation of the outer diameter (mm) of an external conductor (braided body) at the time of shape | molding an external conductor (braided body) by applying the external conductor (braided body) formation process P11 is shown in FIG. The fluctuation of the outer diameter (mm) of the conductor (braid) is shown in FIG. 12, and both were compared.
[0069]
As a result, it is shown that by forming the outer conductor with a forming die, the outer diameter becomes constant and becomes a perfect circle, and the variation thereof is also reduced. The outer diameter was measured by the same method as the outer diameter measurement of the foamed insulator.
[0070]
Further, FIG. 13 shows measured values of characteristic impedance values (Ω) when foamed insulators and outer conductors are molded by applying the insulator forming step P1 and the outer conductor (braided body) forming step P11. The measured value of the characteristic impedance value (Ω) is shown in FIG. 14, and both were compared.
[0071]
As a result, when the foamed insulator and the outer conductor are molded, the characteristic impedance values are all shown as 51.0 ± 1Ω with a margin. The characteristic impedance value was measured by the TDR method.
[0072]
【The invention's effect】
As described above, according to the present invention, a high-precision foamed coaxial cable having an inner conductor, a foamed insulator formed on the outer periphery of the inner conductor, and an outer conductor formed on the outer periphery of the foamed insulator. In the manufacturing method, a winding step of forming a foamed insulator by winding a porous tape body having a porosity of 60% or more around an internal conductor supplied from a supply unit, and a foamed insulator formed by the winding step The By a primary molding step of inserting and molding a primary molding die having a predetermined inner diameter and a secondary molding step of inserting and molding a secondary molding die having a predetermined inner diameter, Insulator molding process for forming a circular shape with a predetermined outer diameter, a braiding process for forming an external conductor by braiding a plurality of conductive thin wires on the outer periphery of the foamed insulator formed in the insulator molding process, and a braiding process The outer conductor formed in step (b) was inserted into an outer conductor molding die having a predetermined inner diameter, and the outer conductor was molded into a predetermined outer diameter and a perfect circle. Therefore, the outer diameter of the high-foamed insulator is not round and uneven, and it is formed in a perfect circle, and the outer conductor of the braided body has no irregularity and variation in outer diameter, and is stably molded into a perfect circle. This makes it possible to manufacture a highly accurate foamed coaxial cable having a characteristic impedance value of ± 1Ω.
[0073]
In particular The insulator forming step includes a primary forming step for forming by inserting through a primary forming die having a predetermined inner diameter, and a secondary forming step for forming by inserting through a secondary forming die having a predetermined inner diameter. Therefore, it is possible to stably obtain a perfect circular insulator with small variations in thickness and outer diameter, in close contact with the inner conductor, and to obtain a stable high-precision foamed coaxial cable that eliminates disconnection and elongation due to molding of the insulator. Can do.
[0074]
In addition, an outer shape holding layer step of forming an extremely thin outer shape holding layer by winding on the outer periphery of the foamed insulator formed in a perfect circle shape with a predetermined outer shape by the insulator forming step was provided. Therefore, since the outer diameter of the insulator of the high-precision foamed coaxial cable and its perfect circular outer shape can be maintained in the molding process, fluctuations in the characteristic impedance value can be reduced.
[0075]
Further, the outer conductor forming step includes a primary forming step in which an outer conductor is inserted into a primary forming die having a predetermined inner diameter and a secondary forming step in which the outer conductor is formed through a secondary forming die having a predetermined inner diameter. It was. Therefore, a perfect circular braided body with a small thickness and outer diameter variation, intimate contact with the insulator, and a constant thickness can be stably obtained. Wire breakage, elongation, damage, peeling of plating, etc. This eliminates the need for stable molding processes and improves quality and productivity.
[0076]
In the outer conductor forming step, the outer conductor is formed by rotating the outer conductor forming die at a predetermined rotational speed. Therefore, even if the outer conductor has a large or uneven outer diameter, the pressure passing through the molding die hole can be reduced by the rotation of the molding die, so that the molding is stabilized and the productivity is improved.
[0077]
In the outer conductor molding step, ultrasonic vibration is applied to the outer conductor molding die so that predetermined vibration is applied in the outer diameter direction of the outer conductor. Therefore, the molding of the outer conductor is stabilized, and there is no damage to the braided body due to rubbing with the molding die and peeling of the plating.
[0078]
In addition, the outer conductor forming step is provided after the braiding step, is provided alone immediately before the outer sheath forming step of the outer sheath formed on the outer periphery of the outer conductor, or both after the braiding step and immediately before the outer sheath forming step. One of them was provided. Therefore, the outer diameter and shape of the outer conductor can be maintained, and a highly accurate foamed coaxial cable having a characteristic impedance value of ± 1Ω can be manufactured.
[0079]
Further, in the outer conductor forming step, when the frictional force between the outer conductor inserted into the primary forming die and the primary forming die is a predetermined value or more, the secondary forming die is rotated at a predetermined number of rotations. Accordingly, it is possible to mold even the outer conductor having a large or uneven outer diameter, variation, and the like, and the molding of the outer conductor can be stabilized and the molding accuracy can be improved.
[0080]
Further, in the outer conductor molding step, ultrasonic vibration is applied to the secondary molding die when the friction force between the outer conductor inserted into the primary molding die and the primary molding die is a predetermined value or more. Accordingly, there are no scratches on the outer conductor in the outer conductor molding step, peeling of the plating layer, and the like, so that molding can be stabilized and the quality of the outer conductor can be improved.
[Brief description of the drawings]
FIG. 1 is a process diagram for explaining a manufacturing method of a high-precision foamed coaxial cable according to an embodiment of the present invention.
FIG. 2 is a perspective view showing a configuration of a high-precision foamed coaxial cable.
FIG. 3 is a view for explaining a method of winding a porous tape body in a high-precision foamed coaxial cable.
FIG. 4 is a view for explaining a method of manufacturing an outer conductor in a high-precision foamed coaxial cable.
FIG. 5 is a view showing a configuration in which ultrasonic vibration is applied to a forming die for an outer conductor in a high-precision foamed coaxial cable.
FIG. 6 is a diagram showing a configuration in which a forming die for an outer conductor in a high-precision foamed coaxial cable is rotated in accordance with frictional force detection.
FIG. 7 is a diagram showing a configuration in which ultrasonic vibration is applied to a forming die of an outer conductor in a high-precision foamed coaxial cable according to frictional force detection.
FIG. 8 is a cross-sectional view showing a state in which an outer diameter holding layer is formed on the outer periphery of the foamed insulator in the high-precision foamed coaxial cable.
FIG. 9 is a diagram showing fluctuations in the outer diameter of the insulator when a foamed insulator is molded by applying the insulator forming step of the present embodiment.
FIG. 10 is a diagram showing fluctuations in the outer diameter of the insulator when the insulator forming step is not applied.
FIG. 11 is a diagram showing fluctuations in the outer diameter of the outer conductor (braid) when the outer conductor (braid) is formed by applying the outer conductor (braid) forming step of the present embodiment.
FIG. 12 is a diagram showing fluctuations in the outer diameter of the outer conductor (braided body) when the outer conductor (braided body) forming step is not applied.
FIG. 13 is a diagram showing measured values of characteristic impedance values when a foamed insulator and an outer conductor are molded by applying the insulator forming step and the outer conductor (braided body) forming step.
FIG. 14 is a diagram showing measured values of characteristic impedance values when the insulator forming step and the outer conductor (braided body) forming step are not applied.
[Explanation of symbols]
1 Inner conductor
2 Foam insulator
3,10a Outer conductor (braided body)
4 Jacket
10 Insulated wire core
15 Tape body supply unit
21 Porous tape body
30a, 30b, 30c, 41, 42 Guide dice
31a, 31b, 43 Molding dies
40 Braiding device
44 Wire for braiding
51 Ultrasonic oscillator
52 Outlet diameter of forming die 43
53 Entrance diameter of die 43
55 Resonant disk
56 vibrator
57 Rotation detection device for braiding device
61 Friction force detector
62 Friction force comparison part
63 Motor controller
64 motor
71 Ultrasonic oscillation controller
80 Cross section of high-precision foamed coaxial cable of this embodiment
85 Cross section of high precision foamed coaxial cable with outer diameter retaining layer
86 Outer diameter retention layer
Y1 direction of rotation
Y2 moving direction

Claims (8)

In a method for producing a high precision foamed coaxial cable having an inner conductor, a foamed insulator formed on the outer periphery of the inner conductor, and an outer conductor formed on the outer periphery of the foamed insulator,
A winding step of forming a foamed insulator by winding a porous tape body having a porosity of 60% or more around the inner conductor supplied from a supply unit;
A primary forming step of forming the foamed insulator formed in the winding step through a primary forming die having a predetermined inner diameter and a secondary forming step of forming through a secondary forming die having a predetermined inner diameter. , An insulator forming step for forming a predetermined outer diameter and a perfect circle,
A braiding step of forming the outer conductor by braiding a plurality of conductive thin wires on the outer periphery of the foamed insulator formed in the insulator molding step;
A high-precision foamed coaxial cable comprising an outer conductor forming step of forming the outer conductor formed in the braiding step into an outer conductor forming die having a predetermined inner diameter and forming the outer conductor into a predetermined outer diameter and a perfect circle. Manufacturing method.   The outer shape holding layer step of forming an ultrathin shape outer shape holding layer by winding on the outer periphery of the foamed insulator formed into a predetermined outer shape and a perfect circle shape by the insulator forming step. A method for producing a high-precision foamed coaxial cable according to 1. The outer conductor forming step includes a primary forming step of forming the outer conductor through a primary forming die having a predetermined inner diameter, and a secondary forming step of forming through a secondary forming die having a predetermined inner diameter. The method for producing a high precision foamed coaxial cable according to claim 1 or 2 . It said outer conductor forming step, high-precision foamed coaxial cable manufacturing method according to claim 1 or 3, characterized in that shaping is rotated by the outer conductor of the outer conductor forming die at a predetermined rotational speed.   2. The high-precision foamed coaxial according to claim 1, wherein in the outer conductor forming step, an ultrasonic vibration is applied to the outer conductor forming die to apply a predetermined vibration in an outer diameter direction of the outer conductor. Cable manufacturing method. The outer conductor forming step is provided after the braiding step, or is provided alone immediately before the outer shell forming step of the outer conductor formed on the outer periphery of the outer conductor, or after the braiding step and immediately before the outer jacket forming step. The method for manufacturing a high-precision foamed coaxial cable according to any one of claims 1, 3 , 4 , and 5 , wherein: In the outer conductor forming step, when the frictional force between the outer conductor inserted through the primary forming die and the primary forming die is a predetermined value or more, the secondary forming die is rotated at a predetermined number of rotations. The manufacturing method of the highly accurate foaming coaxial cable of Claim 3 . In the outer conductor molding step, ultrasonic vibration is applied to the secondary molding die when a frictional force between the outer conductor inserted into the primary molding die and the primary molding die is a predetermined value or more. The manufacturing method of the highly accurate foaming coaxial cable of Claim 3 .

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