JP2010287410A - Hollow core body for coaxial cable, method of manufacturing the same, and coaxial cable and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance strength of an insulator of a hollow core body to prevent degradation of electric characteristics due to collapse of the insulator. <P>SOLUTION: In the manufacturing method of a hollow core body 1 for a coaxial cable provided with an insulator 3 having an inner side insulation layer 3A for covering an inner conductor 2 on an outer circumference of the inner conductor 2, ribs 3r extending from the inner side insulation layer 3A radially, and an outer side insulation layer 3C of a cylindrical shape to be connected with an outer end of a rib 3r, it is established that a thickness Ti of the inner side insulation layer 3A<a thickness Tr of the rib 3r<a thickness To of the outer side insulation layer 3C in a state that the diameter and electric characteristics of the insulator 3 are to be constant. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hollow core body for an ultrafine coaxial cable mainly used for internal wiring of a mobile phone or a notebook personal computer (personal computer) and a manufacturing method thereof, and a coaxial cable including the hollow core body and a manufacturing method thereof.

  Ultra-fine coaxial cables with an outer diameter of about 0.8 mm are used for the internal wiring of mobile phones and notebook computers.

  The ultra-thin coaxial cable is a hollow core body provided with an insulator on the outer periphery of the inner conductor, an outer conductor is provided on the outer periphery of the hollow core body, and an outer sheath is provided on the outer periphery of the outer conductor. (See Patent Document 1).

  The insulator in the hollow core body has a hollow structure with a gap inside so as to have a good dielectric constant.

  Specifically, as shown in FIG. 4, the insulator 11 in the hollow core body 10 includes an inner insulating layer 11A covering the inner conductor 12, ribs 11r extending radially from the inner insulating layer 11A, and outer ends of the ribs 11r. A structure having a cylindrical outer insulating layer 11C to be connected, and a gap 11s is formed by a rib 11r between the inner insulating layer 11A and the outer insulating layer 11C. In FIG. 4, reference numeral 13 denotes an outer conductor, and 14 denotes an outer coating.

  In the conventional hollow core body 10, the inner insulating layer 11A, the rib 11r, and the outer insulating layer 11C are generally formed to have substantially the same thickness.

JP 2003-249129 A

  By the way, in the coaxial cable having the hollow core body as described above, when a caulking type connector is attached to the end portion, the insulator is crushed by tightening the connector at the end portion of the coaxial cable, and the electrical characteristics of the portion are Deterioration may occur and phenomena such as reflection may occur.

  In addition, when manufacturing a coaxial cable, there is a concern that the insulator is crushed and the electrical characteristics are deteriorated in the process of providing the outer conductor on the outer periphery of the hollow core body.

  In view of the above-described problems, an object of the present invention is to increase the strength of an insulator in a hollow core body, suppress collapse of the insulator due to attachment of a connector or the like, and prevent deterioration of electrical characteristics.

  In order to achieve the above-mentioned problems, it is conceivable to increase the outer diameter of the hollow core body or reduce the gap inside the hollow core body. However, in these countermeasures, the outer diameter of the coaxial cable exceeds the allowable standard. The required electrical characteristics may not be obtained.

  In view of the above circumstances, the inventor of the present invention has conducted various experiments and studied. When the thicknesses of the inner insulating layer, rib, and outer insulating layer of the insulator are set to a predetermined relationship, the insulator The inventors have found that it is possible to increase the strength of the insulator while keeping the outer diameter and electrical characteristics (dielectric constant) of the resin at required values, and have come up with the following inventions.

That is, the method for manufacturing a hollow core body according to the present invention includes an inner conductor and an insulator provided on the outer periphery of the inner conductor, and the insulator includes an inner insulating layer covering the inner conductor and an inner insulating layer. A method of manufacturing a hollow core body for a coaxial cable having a radially extending rib and a cylindrical outer insulating layer connected to an outer end of the rib, wherein the outer diameter and electrical characteristics of the insulator are constant. Then, the thickness Ti of the inner insulating layer, the thickness Tr of the rib, and the thickness To of the outer insulating layer,
Ti <Tr <To
It is characterized in that it is set to the relationship.

  In the above configuration, the outer diameter of the insulator is set in advance corresponding to the standard outer diameter of the coaxial cable including the hollow core body manufactured by the manufacturing method of the present invention. For example, when the coaxial cable is a very thin coaxial cable having an outer diameter of about 0.8 mm, the outer diameter of the insulator is set to 0.6 mm or an approximate value thereof. In addition, the electrical characteristic of the insulator is specifically a dielectric constant, and when the coaxial cable including the hollow core body manufactured by the manufacturing method of the present invention is an ultrafine coaxial cable, the characteristic impedance is 50Ω. Thus, the dielectric constant ε of the insulator is set to 1.382.

  In the hollow core body obtained by the above manufacturing method, the strength of the insulator can be increased while maintaining the outer diameter and electrical characteristics of the insulator at required values, and this can be confirmed from the experimental results. Therefore, it is possible to eliminate the collapse of the insulator due to the attachment of the connector.

Furthermore, in the present invention, the thickness To of the outer insulating layer is set to the thickness Ti of the inner insulating layer,
2 × Ti ≦ To ≦ 3 × Ti
It is desirable to set this relationship.

  In the above configuration, the strength of the insulator can be further increased, and the collapse of the insulator can be reliably eliminated.

  The method for manufacturing a coaxial cable according to the present invention is a method for manufacturing a coaxial cable in which an outer conductor and an outer coating for covering the outer conductor are provided on the outer periphery of the hollow core body, and the hollow core body is It manufactures with the manufacturing method of the hollow core body which was made.

Furthermore, the hollow core body according to the present invention includes an inner conductor and an insulator provided on the outer periphery of the inner conductor, and the insulator extends radially from the inner insulating layer covering the inner conductor and the inner insulating layer. A hollow core body for a coaxial cable having a rib and a cylindrical outer insulating layer connected to the outer end of the rib, the inner insulating layer thickness Ti, the rib thickness Tr, and the outer insulating layer thickness of the insulator. To
Ti <Tr <To
It is characterized by being set to the relationship of.

  Further, the coaxial cable according to the present invention is a coaxial cable provided with a hollow core body, and provided with an outer conductor and an outer sheath covering the outer conductor on the outer periphery of the hollow core body. It is a hollow core body according to the present invention.

  According to the present invention, since the strength of the insulator in the hollow core body is improved, the insulation is prevented from being crushed by attaching a connector or the like, and electrical characteristics can be prevented from being deteriorated due to the insulation being crushed.

  In this case, the outer diameter and electrical characteristics of the insulator are maintained at the required values, and the outer diameter of the hollow core body and coaxial cable is larger than the allowable standard, or the required electrical characteristics cannot be obtained. There is no.

Sectional drawing of the hollow core body obtained by the manufacturing method of this invention. The schematic block diagram of the measuring apparatus which measures mechanical characteristics, such as a hollow core body obtained by the manufacturing method of this invention. Sectional drawing of the coaxial cable obtained by the manufacturing method of this invention. Sectional drawing of the coaxial cable containing the conventional hollow core body.

  The details of the present invention will be described with reference to FIG. 1. A coaxial cable hollow core body 1 obtained by the manufacturing method of the present invention includes an inner conductor 2 and an insulator 3 provided on the outer periphery of the inner conductor 2. Consists of. The insulator 3 is entirely made of resin, for example, fluorine resin, and is connected to the inner insulating layer 3A covering the inner conductor 2, the ribs 3r extending radially from the inner insulating layer 3A, and the outer ends of the ribs 3r. A gap 3s is formed between the ribs 3r and 3r adjacent to each other in the circumferential direction. In this embodiment, the inner conductor 2 is a bundle of many thin wires. Further, the number of ribs 3r is six and they are provided radially and equiangularly.

In the above configuration, the thickness Ti of the inner insulating layer 3A of the insulator 3, the thickness Tr of the rib 3r, and the thickness To of the outer insulating layer 3C are:
Ti <Tr <To ……………………… (I)
The relationship is set. This is based on the result of an experiment described later.

  In addition, the relationship of the said (A) type shall be set on condition that the outer diameter of the insulator 3 (it is also the outer diameter of the outer side insulating layer 3C) is kept constant, and this is not changed.

  Further, the relationship of the formula (a) is set on the condition that the electrical characteristics of the insulator 3, specifically, the dielectric constant is kept constant and is not changed.

  In this case, the dielectric constant of the insulator 3 is calculated. The method of calculating the dielectric constant of the insulator 3 will be described as follows.

First, considering the dielectric constant εb of a layer (intermediate insulating layer 3B) composed of the rib 3r and the gap 3s therebetween, the dielectric constant εb is:
εb = 1 + (ε−1) × K (b)
It is.

Here, ε is a dielectric constant of a fluororesin that is a material resin of the insulator 3, and ε = 2.041. Further, K is a filling rate and indicates a ratio occupied by the ribs 3r in the cross-sectional area of the intermediate insulating layer 3B.
K = rib height × thickness × number / [π / 4 × (inner diameter of outer insulating layer ²⁻ outer diameter of inner insulating layer ² )] …… (c)
It is.

  The filling rate K is 6 ribs 3r, the height of the ribs 3r is 0.228 mm, the thickness Tr is 0.03 mm, and the outer insulating layer 3C as in Example 3 shown below. When the inner diameter of the inner insulating layer 3A is 0.51 mm and the outer diameter of the inner insulating layer 3A is 0.282 mm, the filling factor K is 0.14, and the dielectric constant εb of the intermediate insulating layer 3B is 1.15.

Next, the dielectric constant εo of the entire insulator 3 is
εo = εa × εb × εc × P
/ (Εa × εb × Q + εb × εc × R + εa × εc × S) (D)
Can be expressed as

Here, εa is the dielectric constant of the inner insulating layer 3A, and εc is the dielectric constant of the outer insulating layer 3C. For P, Q, R, and S,
P = ln (outer diameter of outer insulating layer / effective outer diameter of inner conductor) ............ (e)
Q = ln (outer diameter of outer insulating layer / inner diameter of outer insulating layer) ............ (f)
R = ln (outer diameter of inner insulating layer / effective outer diameter of inner conductor)
S = ln (inner diameter of outer insulating layer / outer diameter of inner insulating layer)
It is represented by each formula.

  The dielectric constant εo of the insulator 3 is obtained from the above equation (d) and the equations (e) to (h). The specific numerical value is εo = 1.382.

  Next, the inventor of the present invention (1) the outer diameter of the insulator 3 is constant, (2) the dielectric constant εo of the insulator 3 obtained by calculation is a predetermined value (εo = 1.382). Under the condition of being, various hollow core bodies were prepared by changing the internal shape of the insulator 3, and some of the hollow core bodies were designated as Examples 1 to 5. Specifically, in Examples 1 to 5, the number of the ribs 3r is 6, the thickness Tr is thicker than the thickness Ti of the inner insulating layer 3A, and the thickness To of the outer insulating layer 3C is thicker than the rib thickness Tr. ing.

  Moreover, the other thing created on the same conditions was made into Comparative Examples 1-5. In the conventional example, the thickness Tr of the rib 3r, the thickness Ti of the inner insulating layer 3A, and the thickness To of the outer insulating layer 3C are equal to each other.

  And each Example 1-5, Comparative Examples 1-5 created as mentioned above, and each hollow core body 1 of a prior art example are between the base 4 and the pressurization stand 5 of the measuring apparatus shown in FIG. A compression test was carried out by placing, and as a mechanical property, the reaction force when contracted by 5% was measured.

  Table 1 shows the internal dimensions and mechanical characteristics of the insulators 3 of Examples 1 to 5, Comparative Examples 1 to 5, and the conventional example.

  Looking at the data in Table 1, as in Examples 1 to 5, the thickness Ti of the inner insulating layer 3A, the thickness Tr of the rib 3r, and the thickness To of the outer insulating layer 3C have a relationship of Ti <Tr <To. In this case, the reaction force against compression is larger than that of the conventional example and Comparative Examples 1 to 5, and it is understood that the mechanical properties are excellent. This is because the rib 3r is comparatively thick, so that it is difficult to undergo buckling deformation, and the outer insulating layer 3C, which is a portion that directly receives a compression external force, has a sufficient thickness to maintain a cylindrical shape. it is conceivable that.

  In the conventional example, the thickness Ti of the inner insulating layer 3A, the thickness Tr of the rib 3r, and the thickness To of the outer insulating layer 3C are the same. In Comparative Examples 1 to 5, the inner insulating layer 3A, the rib 3r, and the outer The thickness relationship with the insulating layer 3C is different from those in Examples 1 to 5, and does not have a relationship of Ti <Tr <To.

  Further, according to the data in Table 1, the insulator 3 is also obtained when the thickness To of the outer insulating layer 3C is 2 × Ti ≦ To ≦ 3 × Ti with respect to the thickness Ti of the inner insulating layer 3A. It can be seen that the strength of is increasing.

  FIG. 3 shows a cross-sectional shape of a coaxial cable obtained by the manufacturing method of the present invention. The coaxial cable 6 includes a hollow core body 1, and an outer conductor 7 and an outer covering 8 that covers the outer conductor 7 are provided on the outer periphery of the hollow core body 1. Among these, the hollow core body 1 is manufactured by the manufacturing method of the hollow core body demonstrated with reference to FIG. Therefore, in the insulator 3 of the hollow core body 1, the thickness Ti of the inner insulating layer 3A, the thickness Tr of the rib 3r, and the thickness To of the outer insulating layer 3C have a relationship of Ti <Tr <To. This is the same as in the case of FIG.

DESCRIPTION OF SYMBOLS 1 ... Hollow core body 2 ... Internal conductor 3 ... Insulator 3A ... Inner insulating layer, Ti ... Thickness of inner insulating layer 3r ... Rib, Tr ... Thickness of rib 3C ... Outer insulating layer, To ... Thickness of outer insulating layer

Claims (5)

The insulator comprises an inner conductor and an insulator provided on the outer periphery of the inner conductor. The insulator includes an inner insulating layer covering the inner conductor, a rib extending radially from the inner insulating layer, and a cylinder connected to the outer end of the rib. A hollow core body for a coaxial cable having a shaped outer insulating layer,
With the outer diameter and electrical characteristics of the insulator being constant, the inner insulating layer thickness Ti, the rib thickness Tr, and the outer insulating layer thickness To are:
Ti <Tr <To
The manufacturing method of the hollow core body for coaxial cables characterized by setting to the relationship of these. The thickness To of the outer insulating layer with respect to the thickness Ti of the inner insulating layer,
2 × Ti ≦ To ≦ 3 × Ti
The manufacturing method of the hollow core body for coaxial cables according to claim 1, wherein the relationship is set as follows. A method for producing a coaxial cable comprising a hollow core body and provided with an outer conductor on the outer periphery of the hollow core body and an outer coating for covering the outer conductor,
A method for manufacturing a coaxial cable, wherein the hollow core body is manufactured by the manufacturing method according to claim 1. The insulator comprises an inner conductor and an insulator provided on the outer periphery of the inner conductor. The insulator includes an inner insulating layer covering the inner conductor, a rib extending radially from the inner insulating layer, and a cylinder connected to the outer end of the rib. A hollow core body for a coaxial cable having an outer insulating layer having a shape,
The thickness Ti of the inner insulating layer of the insulator, the thickness Tr of the rib, and the thickness To of the outer insulating layer are:
Ti <Tr <To
A hollow core body for a coaxial cable, characterized in that the relationship is set as follows. A coaxial cable provided with a hollow core body, and provided with an outer conductor on the outer periphery of the hollow core body and an outer covering for covering the outer conductor,
The said hollow core body is a hollow core body of Claim 4, The coaxial cable characterized by the above-mentioned.

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