CN1545102A

CN1545102A - Coaxial cable

Info

Publication number: CN1545102A
Application number: CNA2003101122864A
Authority: CN
Inventors: 陈伟乐; 肖翠玉; 陈占山
Original assignee: ZHUHAI YUXUN COAXIAL CABLE CO Ltd
Current assignee: ZHUHAI YUXUN COAXIAL CABLE CO Ltd
Priority date: 2003-11-24
Filing date: 2003-11-24
Publication date: 2004-11-10

Abstract

The invention discloses a coaxial cable, in order to provide a waterproof, moistureproof, stable-transmission, longer-service life coaxial cable. It includes an inner conductor, an insulating layer, an outer conductor and an outer protective case, where the insulating layer is composed of an inner thin layer and a foamed insulating layer, the inner thin layer closely adheres to the inner conductor, the foamed insulating layer is bonded with the inner thin layer, and the inner conductor, the inner thin layer, the foamed insulating layer, the outer conductor and the outer protective case are set in turn from inside to outside in the radial direction. It can be applied to wire transmission systems.

Description

Coaxial cable

Technical field

The present invention relates to a kind of coaxial cable.

Background technology

Coaxial cable is general main by inner wire, insulating barrier, outer conductor and oversheath are formed, in the replacement process of coaxial cable product, difference because of its insulating barrier, successively go through solid polyethylene-insulated coaxial cable, the chemical blowing polyethylene-insulated coaxial cable, vertical cellular type polyethylene-insulated coaxial cable, because it is poor that solid polyethylene coaxial cable exists flexibility, many and the dielectric constant of materials makes shortcomings such as the attenuation constant of cable is big greatly, there is moisture-sensitive in vertical cellular type polyethylene-insulated coaxial cable, shortcomings such as transmission performance instability, the chemical blowing polyethylene-insulated coaxial cable exists environmental protection poor, foam degrees is low, shortcomings such as attenuation constant is bigger than normal, very fast by the 4th generation product---the physically foamed pe insulation coaxial cable replaces.China Patent No. is CN1146607, was on April 2nd, 1997 in open day, name is called " method that is used for insulating material, coaxial cable and the manufacturing coaxial cable of coaxial cable ", this application case is to mix to extrude by optimal proportion and form the physically foamed pe insulation coaxial cable in the conductor being used for the polyethylene material of physical blowing and nucleator, because its environmentally safe, foam degrees height, flexibility is good, attenuation constant is little and transmission performance is stable etc., and advantage has obtained application widely.But in the high-frequency transmission network, the conductive surface state is very big to the influence of high-frequency transmission effect, even after qualified inner wire is used for cable, because of the intrusion of moisture also can cause the inner wire oxidation to influence the transmission performance and the life-span of cable.Though the surface of the foaming insulation layer of physically foamed pe insulation coaxial cable is smooth, but it is one deck film as thin as a wafer, the foaming micro-pore wall that is foamed insulation top layer when extruding mould is connected to form, mechanical strength is very low, be easy to damage, particularly in semi-finished product circulation process or finished product easily cause inner wire and the relative displacement of polyethylene foamed insulating barrier when laying and form the gap that can enter moisture or moisture, and make the inner wire surface oxidation, influence transmission performance, shorten cable useful life.So existing physically foamed pe insulation coaxial cable has the following disadvantages: waterproof, humidity resistance are poor, the transmission performance instability, and the life-span is shorter.

Summary of the invention

Technical problem to be solved by this invention is to overcome the deficiencies in the prior art, and a kind of coaxial cable is provided, and this coaxial cable waterproof, humidity resistance are good, and transmission performance is stable, and the life-span is longer.

Technical scheme used in the present invention is: the present invention includes inner wire, insulating barrier, outer conductor and oversheath, described insulating barrier is made up of interior thin layer and foaming insulation layer, thin layer and described inner wire tight adhesion are together in described, described foaming insulation layer and described interior thin layer are bonded as one, and described inner wire, described interior thin layer, described foaming insulation layer, described outer conductor and described oversheath radially are provided with successively from inside to outside.

Thin layer is the solid viscosity heat insulating lamina of being made by the polyolefin material in described.

The invention has the beneficial effects as follows: owing between inner wire and foaming insulation layer, the interior thin layer that the layer of polyethylene Insulation Material is mixed with sizing is set, should not only be bonded as one by interior thin layer with inner wire, and also be bonded as one with the polyethylene foamed insulating barrier, thereby make cable in semi-finished product circulation process or finished product lay Shi Buhui and make inner wire and polyethylene foamed insulating barrier produce relative displacement and form the gap that can enter moisture or moisture, waterproof, the humidity resistance of cable have been improved, make its transmission performance more stable, the life-span is longer.

Description of drawings

Fig. 1 is a structure cross-sectional schematic of the present invention;

Embodiment

As shown in Figure 1, the present invention includes inner wire 1, insulating barrier, outer conductor 3 and oversheath 4, wherein insulating barrier is made up of interior thin layer 5 and foaming insulation layer 6, and described inner wire 1, interior thin layer 5, foaming insulation layer 6, outer conductor 3 and oversheath 4 are provided with successively from inside to outside.

Inner wire 1 is the carrier of information such as transmission cable TV signal, digital signal, transmission frequency bandwidth, frequency height, general transmission frequency is at 5MHz～1000MHz or higher, and requiring inner wire 1 is that size uniformity, the flawless rounding conductor of smooth in appearance are to guarantee transmission quality.Interior thin layer 5 is to extrude one deck polyolefin material evenly to mix the solid viscosity heat insulating lamina that is extruded in outside the inner wire with sizing outside inner wire 1, this thin layer can closely adhere to each other with inner wire, can stop moisture moisture to enter effectively, prevent the inner wire oxidation stain and influence its transmission performance; Also can peel off simultaneously and be beneficial to continued access, interior thickness of thin layer is generally about 0.3mm below 1mm.Foaming insulation layer 6 is after the high expanded polyolefin material of physics and nucleator are mixed by optimal proportion, add in the physics bubble extruder occurred frequently, the nitrogen that in extruder, adds stable chemical performance, rotatablely move through screw rod and to become compression with fused polyolefin mixture and nitrogen are mixing, the foaming body of uniform and smooth, extrude the back and form the foamed insulation body, and with interior thin layer 5 bonding becoming one, this foaming layer is the foaming structure high conformity not only, and smooth in appearance rounding, this insulating barrier dielectric constant is little, dielectric loss value is low, so good electric property and transmission performance are arranged in high-frequency transmission.Outer conductor 3 also claims screen, it is one deck outer conductor that outside foaming insulation layer 6, increases, its effect is the loop that is made of the signal of telecommunication internal and external conductor, guarantee that the signal of telecommunication transmits in outer conductor, transmission signals is not revealed, also make the external electromagnetic signal can not invade outer conductor inside, thereby prevented external interference.Oversheath 4; it is the outermost layer of cable; cable is played comprehensive protective effect; as moistureproof, prevent ageing of insulation, anti-slight mechanical damage etc., also can make some marks and sign on its outer surface, as manufacturer's title, product type, specification, metering or product user title etc.; described oversheath 4 can be a pe sheath; also can be pvc sheath, can also make two sheaths or low smoke and zero halogen sheath according to specific (special) requirements, present embodiment adopts pvc sheath.

Claims

1, a kind of coaxial cable, comprise inner wire (1), insulating barrier, outer conductor (3) and oversheath (4), described inner wire (1), described insulating barrier, described outer conductor (3) and described oversheath (4) radially are provided with successively from inside to outside, it is characterized in that: described insulating barrier is made up of interior thin layer (5) and foaming insulation layer (6), in described thin layer (5) be arranged on described inner wire (1) outer and with described inner wire (1) tight adhesion together, described foaming insulation layer (6) is arranged on and is bonded as one between thin layer (5) and the described outer conductor (3) and with described interior thin layer (5) in described.

2, coaxial cable according to claim 1 is characterized in that: thin layer (5) is the solid viscosity heat insulating lamina of being made by the polyolefin material in described.