KR102603726B1 - Coaxial cable for vehicle - Google Patents

Abstract

The present invention relates to a coaxial cable for vehicles with improved heat resistance and durability so that it can be installed in high temperature spaces within a vehicle.

Description

Coaxial cable for vehicles {COAXIAL CABLE FOR VEHICLE}

The present invention relates to a coaxial cable for vehicles. More specifically, the present invention relates to a coaxial cable for vehicles with improved heat resistance and durability so that it can be installed in high temperature spaces within a vehicle.

Coaxial cable is a communication cable. A coaxial cable as a communication cable may be composed of an inner conductor, an insulator, an outer conductor, and an outer jacket.

These coaxial cables are also applied inside vehicles. While the vehicle is running, the temperature in the vehicle engine room is high due to engine heat.

In the case of coaxial cables, an insulator is interposed between the inner conductor and the outer conductor, and this insulator is often made of foamed resin to lower the dielectric constant and attenuation.

However, when a coaxial cable is installed while exposed to a high-temperature environment inside a vehicle, the general foam insulator can be easily damaged by heat and communication characteristics such as attenuation may deteriorate, and when a general foam insulator is applied, the flexibility of the coaxial cable is improved. However, when installed in a vehicle that continuously experiences vibration or shock, problems such as bending of the coaxial cable may occur.

Therefore, a coaxial cable for vehicles with improved heat resistance and durability is required to be installed inside a vehicle where the temperature rises significantly and vibration and shock continuously occur.

The invention aims to solve the problem of providing a coaxial cable for vehicles with improved heat resistance and durability so that it can be installed in high temperature spaces within a vehicle.

In order to solve the above problem, the present invention includes an inner conductor; an insulator surrounding the inner conductor and constructed by irradiating and crosslinking a foamed resin; a first external conductor surrounding the outside of the insulator; a second external conductor surrounding the outside of the first external conductor; and a cable jacket surrounding the second external conductor, wherein the tensile residual ratio after a heating test using a constant temperature bath for 168 hours (hr) at 136 ± 3 degrees Celsius is 70% or more, and the cable jacket is heated at 136 ± 3 degrees Celsius. It is possible to provide a coaxial cable for a vehicle, characterized in that the elongation residual rate after a heating test using a constant temperature bath for 168 hours (°C) is 45% or more and the total diameter is 3.5 millimeters (mm) to 3.8 millimeters (mm). there is.

In this case, the insulator may be crosslinked expanded polyethylene (XLPE), which is formed by irradiating and crosslinking expanded polyethylene (PE).

In addition, the room temperature tensile strength of the vehicle coaxial cable may be 1.05 Kgf/㎟ or more, and the room temperature elongation of the insulator may be 150% or more.

And, the outer diameter of the insulator may be 2.08 millimeters (mm) to 2.12 millimeters (mm).

Here, the inner conductor is made of annealed copper wire material, and when the diameter is in the range of 0.80 millimeter (mm) to 0.84 millimeter (mm), it can satisfy the standard attenuation standard among the high frequency coaxial cable standards (KS C 3610).

In this case, the first external conductor may be a metal-coated tape.

Additionally, the metal-coated tape may be an aluminum mylar tape.

In addition, the second external conductor may be a braided layer made of tin-plated annealed copper wire with a diameter of 0.08 millimeters (mm) to 0.12 millimeters (mm) and a shielding ratio of 85% to 95%.

Here, the cable jacket may be made of polyvinyl chloride (PVC).

Additionally, the degree of crosslinking of the insulator may be 40% or more.

According to the coaxial cable for vehicles according to the present invention, heat resistance and durability can be improved when installed in a high temperature vehicle interior space by applying irradiation crosslinked expanded polyethylene as an insulator.

In addition, according to the coaxial cable for vehicles according to the present invention, the communication characteristics according to the standard specifications can be satisfied even if the insulator is made of irradiation crosslinked expanded polyethylene.

1 shows a multi-stage stripped perspective view of one embodiment of a coaxial cable for a vehicle according to the present invention.
FIG. 2 shows a cross-sectional view taken along line A-A' of the coaxial cable for a vehicle according to the present invention shown in FIG. 1.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosure will be thorough and complete, and so that the spirit of the invention can be sufficiently conveyed to those skilled in the art. Like reference numerals refer to like elements throughout the specification.

Figure 1 shows a multi-stage stripped perspective view of one embodiment of the vehicle coaxial cable 100 according to the present invention, and Figure 2 is a cross-sectional view taken along line A-A' of the vehicle coaxial cable 100 according to the present invention shown in Figure 1. shows.

The coaxial cable 100 according to the present invention shown in FIG. 1 includes an inner conductor 10, an insulator 20, a first outer conductor 30, a second outer conductor 40, and It may be configured to include a cable jacket 50.

The internal conductor 10 is provided to transmit communication signal data. The internal conductor 10 is made of a material such as annealed copper wire, which enables flexible bending while improving communication performance, and has lower resistance than aluminum or CCA materials, thereby reducing heat generation. The diameter d1 of the inner conductor may range from 0.80 millimeters (mm) to 0.84 millimeters (mm).

An insulator 20 may be provided outside the inner conductor 10. The insulator 20 functions to insulate the internal conductor 10.

The insulator 20 according to the present invention may be made of a cross-linked resin material. In particular, the insulator 20 of the coaxial cable 100 according to the present invention may be made of irradiation crosslinked expanded polyethylene (XLPE) material. General (foamed) polyethylene (PE) has a low melting point, but cross-linked polyethylene (XLPE) has greatly improved mechanical and thermal properties, enabling higher operating temperatures.

Therefore, the degree of crosslinking (gel fraction) of the irradiation crosslinked expanded polyethylene is preferably at least 40% to enhance heat resistance and satisfy the tensile or elongation residual ratio by the heating test described later. Here, irradiation crosslinking is a method of performing crosslinking by applying electron beams, gamma rays, etc.

The irradiation-crosslinked expanded polyethylene (XLPE) is a material that imparts thermosetting viscoelastic properties by crosslinking expanded polyethylene (PE) to crosslink the foamed polyethylene structure. The present invention provides a material that provides thermosetting viscoelastic properties by crosslinking expanded polyethylene (PE). It utilizes features such as improved heat resistance and strength compared to polyethylene.

That is, conventionally, the insulator 20 of the coaxial cable 100 used a foamed resin by injecting gas to form pores in the insulator 20 manufacturing process. In the case of foamed resin, when the insulator 20 is constructed by foaming, a large number of pores are formed inside, thereby lowering the dielectric constant of the insulator 20 and improving attenuation.

However, foamed resin materials have poor heat resistance and physical properties, so it is difficult to guarantee heat resistance and durability when installed in the interior space of a vehicle where the temperature rises significantly and vibration and shock can continuously occur.

For this purpose, the application of non-foamed cross-linked polyethylene can be considered, but it is difficult to satisfy the communication characteristics.

Therefore, in the case of the coaxial cable 100 according to the present invention, irradiation-crosslinked foamed polyethylene (XLPE) is applied as the insulator 20, and has superior heat resistance and durability than a coaxial cable using general foamed polyethylene (foamed PE) as an insulator. In addition, communication characteristics are improved compared to coaxial cables using general cross-linked polyethylene (XLPE), and communication standards such as attenuation can be satisfied.

Specifically, the coaxial cable 100 according to the present invention has a diameter (d1) of the inner conductor in the range of 0.80 millimeters (mm) to 0.84 millimeters (mm), and an overall diameter (D) of the coaxial cable in the range of 3.5 millimeters (mm) to 3.8 millimeters. (mm), and the insulator 20 is made of irradiation-crosslinked expanded polyethylene (XLPE), and the outer diameter d2 of the insulator 20 is 2.08 millimeters (mm) to 2.12 millimeters (mm). It was confirmed that the standard attenuation specifications among the C 3610 high frequency coaxial cable specifications were satisfied.

When changing the insulator 20 from a foamed resin to a irradiation-crosslinked foamed resin, communication performance, especially attenuation, may become a problem. However, if the diameter conditions of the inner conductor, insulator 20, and the entire cable are satisfied as above, heat resistance can be improved. It was confirmed that there was no problem in communication performance even when cross-linked expanded polyethylene was used as a cross-linked resin with improved durability.

Among the KS C 3610 high-frequency coaxial cable standards, the standard attenuation standard measures the ratio of the output signal to the input signal for various frequencies using a network analyzer on a sample of 10 meters (m) or more, and measures the amount of signal loss in dB units. This can be done by converting to 1 meter units.

In addition, even if the insulator 20 is made of foamed resin, for example, foamed polyethylene, the tensile strength and elongation in a room temperature environment may not be a problem, but the coaxial cable 100 may not be used in a high temperature vehicle interior environment. When installing, it may be difficult to satisfy the required tensile strength and elongation rate, so it is necessary to verify this through tensile residual rate and elongation residual rate tests.

Therefore, the coaxial cable 100 according to the present invention uses irradiation-crosslinked expanded polyethylene as the insulator 20, and meets the requirements for rubber and plastic insulated wire test methods KS C 3004 (C IEC 60811-1-1) and Low Voltage Primary Cable. Through testing according to the SAE J1128 test method (standard), the tensile residual ratio after a 168 hour (hr) constant temperature bath heating test at 136 ± 3 degrees Celsius (℃) was more than 70%, and the It was confirmed that the enhanced tensile residual rate and extension residual rate conditions of 45% or more were satisfied after the 168-hour (hr) constant temperature bath heating test.

The heating test is performed by hanging a sample on a stand in a state of less than 2% of the internal volume of the thermostat and in a non-contact condition with adjacent samples and the inner wall of the tester, heating it for the above-mentioned temperature and time, taking it out to room temperature, and measuring the residual ratio after 4 hours. You can.

For reference, the room temperature tensile strength of the vehicle coaxial cable 100 according to the present invention is 1.05 Kgf/㎟ or more, and the room temperature elongation of the insulator 20 may be 150% or more.

However, in the case of the coaxial cable (100) to which a conventional foamed resin is applied, the tensile residual ratio after 48 hours (hr) at 100 ± 2 degrees Celsius (℃) is more than 80%, and the remaining tensile strength at 100 ± 2 degrees Celsius (℃) is 48% or more. The conditions for tensile residual and elongation residual that the elongation residual after the time (hr) heating test is 60% or more are satisfied, but the tensile residual after the 168 hour (hr) heating test at 136 ± 3 degrees Celsius is more than 70%, It was confirmed that the durability in a high-temperature vehicle interior environment was not reliable as the condition of elongation residual ratio of more than 45% after a 168-hour (hr) heating test at 136 ± 3 degrees Celsius (℃) was not satisfied.

In reality, the internal temperature of the engine room, etc. may rise to over 100 degrees when the vehicle is driven, so a heating test for about 48 hours (hr) at 100 ± 2 degrees Celsius (℃) cannot be a sufficient durability test for automotive coaxial cables. .

Additionally, a first external conductor 30 may be provided outside the insulator 20.

The first external conductor 30 may be a metal-coated tape, and specifically, the metal-coated tape may be an aluminum mylar tape.

The first external conductor 30 is provided to primarily electrically shield the internal conductor 10.

A second external conductor 40 surrounding the first external conductor 30 may be provided outside the first external conductor 30 .

The first external conductor 30 is a metal sheet added to a tape, etc., and the first external conductor 30 and the second external conductor 40 can perform an independent shielding layer function while being insulated from each other. .

The first external conductor 30 functions as a primary shielding layer, and the second external conductor 40 functions as a secondary shielding layer to ensure stable shielding performance.

The second external conductor 40 may be a braided layer composed of a plurality of tin-plated annealed copper wires 41. Since the braided layer is made of tin-plated annealed copper wire, corrosion resistance can be improved compared to the case where a braided layer made of aluminum is used, and the tensile strength, etc. can be improved compared to the case where the braided layer is made of CCA, etc., so the braided layer By using a tin-plated annealed copper wire (41), corrosion resistance and durability against corrosion can be improved in a harsh vehicle interior environment.

It is preferable that the shielding ratio of the braided layer of tin-plated annealed copper wire with a diameter of about 0.08 millimeters (mm) to 0.12 millimeters (mm) constituting the second external conductor 40 is about 85% to 95%. For this purpose, the sum/number of braided layers can be configured to be about 6/16.

And, the outer diameter of the second external conductor 40 may be 2.3 millimeters (mm) to 2.7 millimeters (mm).

Additionally, a cable jacket 50 may be provided outside the second external conductor 40.

The cable jacket 50 is preferably made of a material such as polyvinyl chloride (PVC), and the overall diameter of the coaxial cable 100 is 3.5 millimeters (mm) to 3.8 millimeters (mm). The thickness can be determined to be in the order of millimeters (mm). Since the cable jacket 50 is made of polyvinyl chloride (PVC), it is more resistant to corrosion than when made of polyethylene, etc., and has the effect of mitigating bending of the coaxial cable, so the coaxial cable of the present invention is used. It can provide sufficient durability even when installed inside a vehicle where there are severe temperature differences and vibrations depending on whether the vehicle is running or the season.

Although this specification has been described with reference to preferred embodiments of the present invention, those skilled in the art may make various modifications and changes to the present invention without departing from the spirit and scope of the present invention as set forth in the claims described below. It will be possible to implement it. Therefore, if the modified implementation basically includes the elements of the claims of the present invention, it should be considered to be included in the technical scope of the present invention.

100: coaxial cable
10: inner conductor
20: insulator
30: first external conductor
40: second external conductor
50: cable jacket

Claims (10)

As a coaxial cable for vehicles,
An inner conductor made of annealed copper wire material and having a diameter of 0.80 millimeter (mm) to 0.84 millimeter (mm);
An insulator that surrounds the inner conductor and is made of crosslinked expanded polyethylene (XLPE), which is made by irradiating and crosslinking expanded polyethylene (PE) to have a crosslinking degree of 40% or more, and has an outer diameter of 2.08 millimeters (mm) to 2.12 millimeters (mm). ;
a first outer conductor surrounding the outside of the insulator and made of aluminum mylar tape;
A second outer conductor surrounding the outside of the first outer conductor and made of tin-plated annealed copper wire with a diameter of 0.08 to 0.12 millimeters (mm) and a braided layer with a shielding ratio of 85% to 95%; and,
It includes a cable jacket surrounding the second external conductor,
The automotive coaxial cable has a tensile residual percentage of 70% or more after a heating test using a thermostat at 136 ± 3 degrees Celsius (℃) for 168 hours (hr), and a tensile residual rate of 70% or more after a heating test using a thermostat at 136 ± 3 degrees Celsius (℃) for 168 hours (hr). The elongation residual rate after the heating test is more than 45%,
The room temperature tensile strength of the automotive coaxial cable is 1.05 Kgf/㎟ or more, and the room temperature elongation of the insulator is 150% or more,
A coaxial cable for vehicles having an overall diameter of 3.5 millimeters (mm) to 3.8 millimeters (mm) and satisfying the standard attenuation specifications among the high frequency coaxial cable specifications (KS C 3610). delete delete delete delete delete delete delete According to paragraph 1,
A coaxial cable for vehicles, wherein the cable jacket is made of polyvinyl chloride (PVC). delete

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