JP3088998B2 - Metal cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to at least one central conductor made of a metal material, an internal insulator provided around the central conductor, and a lateral width longer than a peripheral length of an outer periphery of the internal insulator. A tape enclosure comprising a tape in which a plastic layer is laminated on an aluminum foil layer and the aluminum foil layer is inwardly wrapped around an internal insulator, and is wrapped and wound in a vertical direction. The present invention relates to a metal cable having an outer insulating coating provided around the metal cable. Such metal cables, especially coaxial drop-in cables, are mainly used in the field of information communication for drop-in to the end of a multiplex digital network.

[0002]

2. Description of the Related Art Metal cables require good communication characteristics and shielding properties to prevent signal leakage and noise intrusion in communication lines.
Cables are required to have extremely high grade communication characteristics and shielding properties. In particular, the quality of the communication characteristics and shielding properties of the coaxial drop-in cable is extremely important. Furthermore, in the case of a coaxial cable used for leading end drawing, a structure that can be freely rolled up is required, and therefore, the outer conductor needs to be flexible and shielded.

[0003] In order to ensure high shielding properties and communication characteristics, it is preferable to use an aluminum pipe as a shielding body or an external conductor, but there is a drawback in that it lacks flexibility. Therefore, in such a conventional shielded metal cable or coaxial cable drop 1, FIG.
As shown in (a), the inner insulator 3 around the center conductor 2
A tape 4 having a lateral width longer than the peripheral length of the outer periphery of the inner insulator 3, wherein a tape 4 in which a plastic layer 4 b is laminated on an aluminum foil layer 4 a is provided around the inner insulator 3 with the aluminum foil 4 a inside. A shield or an outer conductor is formed by overlapping one edge portion 4A with the edge portion 4B directly in contact with the other internal insulator by a length longer than the peripheral length of The periphery is covered with an external insulating coating 5.

[0004]

SUMMARY OF THE INVENTION However, FIG.
In this conventional shielded metal cable or coaxial drop-in cable, the shield or the outer conductor as the tape enclosure has no contact with the aluminum foil layer at the edge portion of the overlapping tape, and the effect of high-frequency shielding is reduced. There is a high possibility that the seam opens due to the bending or twisting of the cable and the high-frequency shielding effect is lost. Deterioration or loss of the high-frequency shielding effect causes noise to be mixed into the signal and leakage of the signal. Unlike an analog signal, even if the noise and the signal leakage are small in a digital signal, it is extremely serious in the information communication system. Cause injury.

Further, as shown in FIG. 1 (b), as a conventional shielded metal cable or a coaxial drop-in cable, the surplus edge portions 6A, 6A, In some cases, the aluminum foil layers of FIG. 6B are attached to each other to form a fin-shaped surplus portion, and the overlap portion is formed by folding over the surrounding portion already in close contact with the internal insulator.

In the case of the conventional coaxial cable drop shown in FIG. 1 (b), the aluminum foil layers as the inner layers of the tape are improved so as to keep contact with each other at the edge portions. However, this contact portion has no resistance to the tensile stress generated when the cable is bent or twisted, and the contact portion may be peeled off.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a shielded metal cable having a tape-type shield or an outer conductor which does not cause peeling even when the cable is bent or twisted and does not cause a reduction or loss of the shielding effect. Or to obtain a coaxial drop cable.

[0008]

In order to achieve this object, the metal cable according to the present invention does not directly contact the edge portions on both sides in the longitudinal direction of the tape enclosure, and does not directly contact the inner insulator. The aluminum foil layer portions of the surplus edge portions on both sides of the tape that have been tightly surrounded and adhered to each other are attached to each other to form a fin-shaped surplus portion, and the fin-shaped surplus portion is folded in two, and then the fin-shaped surplus portion is formed. The plastic layer of the above is folded on the plastic layer of the surrounding portion which is already in close contact with the inner insulator to form an overlap portion, and the end faces of both edge portions of the tape surrounding body are sealed in the plastic layer. It is characterized by.

According to the present invention, the fin-shaped surplus portions are brought into close contact with the aluminum foil layers to maintain the continuity of the aluminum foil layers,
Also, the fin-shaped surplus portion is folded in two, and then the plastic layer of the fin-shaped surplus portion is folded on the plastic layer of the surrounding portion which is already in close contact with the internal insulator to form an overlap portion, and both sides of the tape surrounding body are formed. Since the end surface of the end portion of the cable is sealed in the plastic layer, peeling is reliably prevented even when the cable is bent or twisted, and loss of the shielding effect is reliably avoided.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a preferred embodiment of the present invention will be described with reference to the drawings.

FIG. 2 shows a preferred embodiment of a metal cable or a coaxial drop cable 10 according to the present invention, wherein the metal cable or the coaxial drop cable 10 is made of at least one metal material (in the embodiment shown, one wire is used). A central conductor (core wire) 11, an internal insulator 12 provided around the central conductor 11, and a lateral width longer than the circumference of the outer periphery of the internal insulator 12. Tape 13
And a plastic layer 13b on the aluminum foil layer 13a.
A tape envelope 13 formed by wrapping a tape 13 laminated with the aluminum foil layer 13a around the inner insulator 12 with the aluminum foil layer 13a in the longitudinal direction, and an outer insulating coating provided around the tape envelope 13 14. The tape enclosure 13 can function as a shield that simply shields the center conductor 11, or can function as an outer conductor in a coaxial cable.

In the case of the metal cable or the coaxial lead-in cable 10 according to the present invention, the end portions on both sides in the longitudinal direction of the tape enclosure 13 are not brought into direct contact with the internal insulator, but are tightly enclosed around the entire circumference of the internal insulator. The aluminum foil portions 13a of the surplus edge portions 13A and 13B on both sides of the surplus tape are adhered to each other to form a fin-shaped surplus portion 15, and the fin-shaped surplus portion 15 is folded in two, and then the fin-shaped surplus portion is formed. The plastic layer 13b is folded over the surrounding plastic layer 13b which is already in close contact with the internal insulator to form an overlap portion, and the end surfaces 13A ', 13B of both edges in the longitudinal direction of the tape envelope 13 are formed. 'In the plastic layer 13b.

In the embodiment shown in FIG. 2, the metal cable or the coaxial drop-in cable 10 has one surplus edge portion 13A and the other surplus edge portion 13B equal in length (see FIG. 2A). ), The fin-shaped surplus portion 15 is folded in half and then the plastic layer 1 of the fin-shaped surplus portion is
3b is folded over the plastic layer 13b of the surrounding portion which is already in close contact with the internal insulator 12 to form an overlap portion, and the end surfaces 13A 'and 13B' of both edge portions in the longitudinal direction of the tape surrounding body 13 are formed. Is enclosed in the plastic layer 13b (see FIG. 2B).

FIG. 3 shows another preferred embodiment of the present invention. In this embodiment, the metal cable or the coaxial lead-in cable 10 has a tape adhered to the inner insulator 12 so that one surplus edge portion 13A is almost twice as long as the other surplus edge portion 13B. Surround (Fig. 3 (a)
), The longer surplus edge portion 13A is wrapped around the shorter surplus edge portion 13B.
A is folded in two, and then the plastic layer 13b of the fin-shaped surplus portion 15 is folded over the plastic layer 13b of the surrounding portion already in close contact with the internal insulator 12 to form an overlap portion, and the tape surrounding body 13 is formed. The end faces 13A 'and 13B' of the edge portions on both sides in the longitudinal direction are sealed in the plastic layer 13b (see FIG. 3B).

In the illustrated embodiment, the thickness of the tape is exaggerated and the overlap portion is shown to be extremely raised. However, in actuality, the tape is an extremely thin tape and does not rise as shown. , Approximates a substantially circular contour. Further, in the embodiment shown in FIG.
A similar tape as a shield 25 having an outer conductor 23 formed of the above-described tape enclosure according to the present invention around the outer insulator 22 and a metal braid 24 interposed outside the outer conductor 23 A shielded coaxial cable 27 having an enclosure and an outer insulating coating 26 on the outermost side
It is.

[0016]

In the conventional example shown in FIG. 1 (b), although the aluminum foil layers (4a) as the inner layers of the tape are improved so as to keep contact with each other at the edge portion, the edge portion (6) of the tape is improved.
A, 6B) at the end face (6A ', 6B').
Since a) is exposed, the contact portion between the aluminum foil layers (4a) has no resistance to the tensile stress generated when the cable is bent or twisted at the time of laying or wiring the cable. 4a) mutual contact parts peel off,
Therefore, there is a possibility that the shielding effect against high-frequency electromagnetic fields may be reduced. However, according to the metal cable or the coaxial lead-in cable of the present invention, the end portions on both sides in the longitudinal direction of the tape enclosure are not directly in contact with the internal insulator, and the tape that is tightly surrounded and surrounded around the entire circumference of the internal insulator is not provided. The aluminum foil portions of the remaining edge portions on both sides are adhered to each other to form a fin-shaped surplus portion, the fin-shaped surplus portion is folded in half, and the plastic layer of the fin-shaped surplus portion is already in close contact with the internal insulator. The wrapped portion is folded over the plastic layer to form an overlap portion, and the end faces of both longitudinal edge portions of the tape enclosure are sealed in the plastic layer, thereby maintaining the continuity of the aluminum foil. Fins that can prevent the reduction of the shielding effect and form an overlapped part that is folded in two and then folded over the surrounding part that is already in close contact with the inner insulator By the surplus portion,
Prevents peeling even when bending or twisting the cable,
Loss of the shielding effect can be reliably avoided.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a conventional shielded metal cable or a coaxial drop cable, and FIG. 1 (a) shows one end portion at an end portion directly contacting another internal insulator. The outer conductor in the form of a tape which is overlapped and wrapped in the vertical direction is shown, and (b) shows the aluminum foil portions on both sides of the surplus tape on both sides of the surplus tape, which are in close contact with the entire circumference of the inner insulator. Adhere to each other to form a fin-shaped surplus,
Fig. 3 shows an outer conductor in the form of a tape which has been folded over an enclosing part already in close contact with the inner insulator to form an overlap.

FIG. 2 is a schematic cross-sectional view of a preferred embodiment of a shielded metal cable or a coaxial drop cable according to the present invention;
(A) shows a state in which the length of the surplus edge portion is made equal to form a fin-shaped surplus portion, and the tape is wrapped and wound in the vertical direction. Fig. 4 shows an outer conductor in the form of a tape having a wrap portion formed thereon.

FIG. 3 is a schematic sectional view of a preferred embodiment of a shielded metal cable or a coaxial drop cable according to the present invention;
(A) shows a state in which one surplus edge portion is twice as long as the other surplus edge portion to form a fin-like surplus portion, and the tape is wrapped around in the vertical direction, and (b) shows Fig. 3 shows an external conductor in the form of a tape in which the fin-shaped surplus is folded in half and then the overlap is formed.

FIG. 4 is a partially cutaway perspective view of a shielded coaxial drop cable according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Shielded metal cable or coaxial lead-in cable (conventional example) 2 Center conductor 3 Inner insulator 4 Tape (shield or outer conductor) 4a Aluminum foil layer 4b Plastic layer 4A, 4B Edge part 5 External insulation coating 6A, 6B Surplus end Edge portion 10 Shielded metal cable or coaxial lead-in cable (the present invention) 11 Center conductor (core wire) 12 Internal insulator 13 Tape (shield or outer conductor) 13a Aluminum foil layer 13b Plastic layer 13A, 13B Surplus edge portion 14 External insulation Coating 15 Fin-shaped surplus portion 21 Center conductor 22 Insulator 23 Tape (outer conductor) 24 Metal braid 25 Tape (shielding) 26 External insulating coating 27 Shielded coaxial lead-in cable

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01B 11/06 H01B 7/18

Claims (6)

(57) [Claims] 1. A tape having at least one central conductor made of a metal material, an internal insulator provided around the central conductor, and a tape having a lateral width longer than a peripheral length of an outer periphery of the internal insulator. A tape laminated with a plastic layer on a foil layer, with the aluminum foil layer inside around the inner insulator,
In a metal cable having a tape envelope formed by wrapping around in a longitudinal direction and an external insulating coating provided around the tape envelope, the length of the tape envelope is reduced.
The edges on both sides in the hand direction are not in direct contact with the inner insulator, but are adhered to the entire circumference of the inner insulator. Form a fin-shaped surplus part, fold this fin-shaped surplus part in two, and then plasticize the fin-shaped surplus part.
Tsu Pula surrounding parts in close contact click layer already inside the insulator
End portions of the edge portion on both sides in the longitudinal direction of the tape enclosure by folding over the stick layer to form an overlap portion
Metal cable characterized in that its surface is sealed in a plastic layer . 2. A method for equalizing the length of one surplus edge portion and the other surplus edge portion, folding the fin-shaped surplus portion in half, and then forming the surplus portion on the surrounding portion already in close contact with the internal insulator. The metal cable according to claim 1, wherein the overlap portion is formed by folding the cable. 3. A tape is tightly surrounded around the inner insulator so that one surplus edge portion is almost twice as long as the other surplus edge portion, and the longer surplus edge portion is shorter. The longer surplus edge portion was folded in two so as to surround the surplus edge portion, and then the fin-shaped surplus portion was folded over the surrounding portion already in close contact with the internal insulator to form the overlap portion. The metal cable according to claim 1. 4. The metal cable according to claim 1, wherein the tape enclosure is a shield that shields a central conductor. 5. The metal cable according to claim 1, wherein the tape surrounding body is an outer conductor outside a center conductor in the coaxial cable. 6. The metal cable according to claim 1, wherein the tape surrounding body is a shield that shields both a center conductor and the outer conductor in the coaxial cable. .