Vehicle Ethernet Cable

Abstract

The present invention relates to an Ethernet cable for vehicles that is based on Low Voltage Differential Signal (LVDS) and enables large-capacity data communication and high-speed transmission required by vehicle network systems, minimizes the overall outer diameter and weight, and has excellent vibration resistance and electrical properties.

Description

[Technical Field]

[0001] The present invention relates to an Ethernet cable for vehicles, and more particularly to an Ethernet cable for vehicles that is based on Low Voltage Differential Signaling (LVDS) and enables large-capacity data communication and high-speed transmission required by vehicle network systems, minimizes overall outer diameter and weight, and has excellent vibration resistance and electrical properties. [Background technology]

[0002] Recently, with the integration of ICT (Information and communication technology) into vehicles, vehicle network systems are evolving into in-vehicle infotainment (IVI) systems that not only provide communication functions between devices within a vehicle, but also provide connected car functions, V2X communication, autonomous driving, remote control services, and more.

[0003] Therefore, there is an increasing demand for large-capacity data processing and high-speed transmission in vehicle network systems. In this regard, a Low Voltage Differential Signal (LVDS) system method that can reduce power consumption by using a low voltage and enable high-speed transmission can be applied.

[0004] LVDS is a general interface standard for high-speed data transmission. In particular, Ethernet cables, which have high transmission characteristics, support a relatively wide bandwidth, and are flexible and heat-resistant, while also being relatively inexpensive to manufacture, are commonly used as a transmission medium for data transmission between various electrical equipment such as lidar sensors, semiconductors, displays, and camera modules within a vehicle.

[0005] Fig. 6 shows a cross-sectional view of an example of a conventional vehicle Ethernet cable. As shown in Fig. 6, the conventional vehicle Ethernet cable 100' comprises a pair of conductor wires 20 twisted together at a large twist pitch, including a plurality of wires 21 and an insulator 23 encasing the entire wires, and an outer jacket 40 encasing the pair of conductor wires 20.

[0006] However, conventional vehicle Ethernet cables 100' require multiple Ethernet cables 100' in proportion to the types of signals to be transmitted, and are not adequately protected against noise caused by mutual influence between the cables.Furthermore, conventional vehicle Ethernet cables 100' are not adequately protected against vibration and impact, and therefore cannot ensure sufficient durability as a vehicle cable.

[0007] Furthermore, when Ethernet cables such as general UTP cables and STP cables are applied to vehicles, there is a problem that such cables are not designed taking into account the electrical characteristics of the LVDS standard, which can cause adverse effects such as malfunctions or transmission loss.

[0008] In addition, when Ethernet cables such as general UTP cables and STP cables are applied to vehicles, they have a structure including four pairs of eight conductor wires, two of which are twisted at a large twist pitch. However, four of the eight conductor wires are usually used for grounding or as spare wires, which results in unnecessary resource waste and increased costs.

[0009] To solve these problems, there is a strong demand for vehicular Ethernet cables that are based on Low Voltage Differential Signaling (LVDS) and enable the large-capacity data communication and high-speed transmission required by vehicular network systems, minimize the total weight, and have excellent electrical properties such as durability against vibration and attenuation or near-end crosstalk. Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention aims to provide a vehicle Ethernet cable that enables large-capacity data communication and high-speed transmission required by vehicle network systems based on Low Voltage Differential Signal (LVDS), minimizes the overall outer diameter and weight, and has excellent vibration resistance and electrical properties. [Means for solving the problem]

[0011] In order to solve the above problem, the present invention provides a pillar member and a periphery of the pillar member, the total cross-sectional area of ​​which is 0.15 to 0.17 mm 2 The present invention provides an Ethernet cable for vehicles, characterized in that the cable comprises four conductor wires each including a plurality of wires and an insulator encasing the plurality of wires, the four conductor wires being twisted together at a twisting pitch of 26 to 34 millimeters (mm), and each pair of the four conductor wires being two wires each can transmit different Low Voltage Differential Signaling (LVDS).

[0012] Here, the twisting pitch of the four conductor wires may preferably be 29 to 31 millimeters (mm).

[0013] Furthermore, the attenuation per unit length (m) of the cable for a 50 MHz test signal can be 0.25 dB or less.

[0014] In addition, for a 50 MHz test signal of the cable, the near-end crosstalk in a 100 meter (m) transmission section can meet 50 dB or more.

[0015] Here, the average diameter (mm) of the strands constituting the four conductor wires may be 0.16 to 0.18 millimeters (mm).

[0016] In this case, each of the four conductor wires is made up of seven wires, and the seven wires may be arranged so that one wire is placed in the center and six wires are circumscribing it.

[0017] The four conductor wires have an insulator thickness of 0.3 to 0.6 millimeters (mm), and can satisfy a characteristic impedance of 90 to 110 ohms (Ω) for a 50 MHz test signal.

[0018] The pillar members may be made of at least one material selected from the group consisting of polyethylene (PE), fluorinated ethylene propylene (FEP), and polyethylene terephthalate (PET), and may have an outer diameter of 0.5 to 0.6 millimeters (mm).

[0019] The four conductor wires may each have an outer diameter of 1.3 to 1.7 millimeters (mm).

[0020] Here, the outer diameter of the cable may be 4.5 to 6.0 millimeters (mm).

[0021] The vehicle Ethernet cable may further include a shielding layer surrounding the four conductor wires, and the shielding layer may include an aluminum-mylar (Al-mylar) tape layer.

[0022] In this case, the shielding layer may include a braided layer including at least one of tin-plated copper and carbon fiber wrapped around the aluminum mylar (Al-mylar) tape layer.

[0023] The aluminum mylar (Al-mylar) tape layer constituting the shielding layer may be wound in a direction different from the twisting direction of the four conductor wires.

[0024] In this case, the vehicle Ethernet cable may further include an outer jacket that encases the shielding layer. [Effects of the Invention]

[0025] The vehicle Ethernet cable according to the present invention minimizes signal and power loss by adjusting the twist pitch of the four conductor wires, enabling high-capacity data communication and high-speed transmission required by vehicle network systems based on Low Voltage Differential Signaling (LVDS).

[0026] Furthermore, in the vehicle Ethernet cable according to the present invention, the cross-sectional area (mm 2 By adjusting the diameter of the cable, the amount of conductor used can be minimized, reducing cable manufacturing costs, and the overall outer diameter and weight of the cable can be minimized, improving the energy efficiency and interior space efficiency of the vehicle.

[0027] Furthermore, with the vehicle Ethernet cable of the present invention, by placing a pillar member at the center, resistance to vehicle vibrations is improved, and by maintaining roundness, overall cable durability can be improved.

[0028] In addition, according to the vehicle Ethernet cable of the present invention, the twisting direction of the four conductor wires and the cross winding direction of the shielding layer are configured to be different from each other, thereby improving the return loss among electrical characteristics and enabling smooth impedance matching of the Ethernet cable even in a high-speed transmission environment. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a perspective view of a vehicle Ethernet cable according to the present invention in a state where the cable has been stripped in multiple stages. [Figure 2] 1 is a cross-sectional view of a vehicle Ethernet cable according to the present invention. [Figure 3] 10 is a graph showing the results of measuring attenuation and near-end crosstalk for each strand diameter depending on the twist pitch of the four conductor wires constituting the vehicle Ethernet cable according to the present invention. [Figure 4] 10 is a graph showing measured return loss when the aluminum Mylar tape layer of the vehicle Ethernet cable according to the present invention is wound laterally in a direction different from the twisting direction of the four conductor wires. [Figure 5] 10 is a graph showing measured return loss when the aluminum Mylar tape layer of the vehicle Ethernet cable according to the present invention is wound laterally in the same direction as the twisting direction of the four conductor wires. [Figure 6] FIG. 1 is a cross-sectional view of a conventional vehicle Ethernet cable. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. The embodiments described herein are provided so that the disclosure will be thorough and complete, and so that the concept of the invention will be fully conveyed to those skilled in the art. The same reference numerals refer to the same elements throughout the specification.

[0031] Recently, with the spread of in-vehicle infotainment (IVI) systems, vehicle networks are being provided with a variety of functions, including satellite navigation, connected car functions, V2X communications, autonomous driving, and remote control services.

[0032] To realize such infotainment functions in vehicles, the number of sensors, radars, or cameras installed inside the vehicle and the vehicle communication cables installed inside the vehicle to connect them to the central processing unit (ECU, etc.) are also increasing significantly. These vehicle cables require the application of cables that can transmit larger amounts of data than before and are capable of high-speed communication.

[0033] In such an environment where high-speed data transmission within a vehicle is required, the Low Voltage Differential Signals (LVDS) method can be applied. This method uses high-speed analog circuit technology to support high bandwidth at low voltage and transmit large amounts of data in gigabit units. In particular, since the main power supply voltage of an automobile is a relatively low voltage of DC 12V or DC 24V, the application of LVDS offers technical and economic advantages in building a vehicle network system.

[0034] Meanwhile, Low Voltage Differential Signaling (LVDS) is an interface standard for high-speed data transmission, and Ethernet cables used as a transmission medium for LVDS must have low signal attenuation to maintain sufficient voltage and waveform to transmit data, and must be configured to minimize electromagnetic interference (EMI) between adjacent Ethernet cables or internal conductors.

[0035] In addition, the use of automotive Ethernet cables connected to various electrical components inside a vehicle is increasing, so they must be lightweight and have sufficient durability to minimize the increase in vehicle weight. They also need to minimize mutual interference, such as noise, between adjacent cables.

[0036] Therefore, an object of the present invention is to provide a vehicle Ethernet cable that is configured to facilitate large-capacity data communication and high-speed transmission required by vehicle network systems based on Low Voltage Differential Signaling (LVDS), minimizes the overall outer diameter and weight, and ensures sufficient durability and excellent shielding performance.

[0037] FIG. 1 is a perspective view of a vehicle Ethernet cable 100 according to the present invention with the sheath removed, and FIG. 2 is a cross-sectional view of the vehicle Ethernet cable 100 according to the present invention shown in FIG.

[0038] As shown in FIGS. 1 and 2, a vehicle Ethernet cable 100 according to the present invention is arranged around a pillar member 10 and the pillar member 10, and has a total cross-sectional area of ​​0.15 to 0.17 mm. 2 The cable includes four conductor wires 20, each of which includes a plurality of strands 21 and an insulator 23 surrounding the strands 21, a shielding layer 30 surrounding the four conductor wires, and an outer jacket 40 surrounding the shielding layer, and the four conductor wires 20 are twisted together at a twisting pitch of 26 to 34 millimeters (mm), and each pair of the four conductor wires 20, each consisting of two wires, is capable of transmitting different Low Voltage Differential Signaling (LVDS).

[0039] The vehicle Ethernet cable 100 according to the present invention has one pillar member 10 disposed at the center, and the pillar member 10 maintains the arrangement of the four conductor wires 20 disposed around the pillar member 10, thereby maintaining the circularity of the cable and protecting the four conductor wires 20 from mechanical vibrations of the vehicle or other external forces during installation of the Ethernet cable 100.

[0040] The pillar member 10 may be made of various polymer resins, such as polyethylene (PE), fluorinated ethylene propylene (FEP), polyethylene terephthalate (PET), polyvinyl chloride (PVC), and polypropylene (PP), and is preferably made of at least one of polyethylene (PE), fluorinated ethylene propylene (FEP), and polyethylene terephthalate (PET). When the pillar member 10 is made of polyethylene terephthalate (PET), it has a relatively high hardness, which can minimize or prevent the pillar member 10 from elongating during cable fabrication.

[0041] The outer diameter of the pillar member 10 is 0.5 to 0.6 mm. If the outer diameter of the pillar member 10 is less than 0.5 mm, there is a problem that the pillar member 10 may stretch or break due to an external force, while if the outer diameter of the pillar member 10 exceeds 0.6 mm, there is a problem that the outer diameter of the pillar member 10 becomes excessively large, which unnecessarily increases the overall outer diameter and weight of the cable.

[0042] The Ethernet cable 100 for a vehicle according to the present invention includes four conductor wires 20 that are responsible for transmitting signals within the vehicle, and the four conductor wires 20 are arranged so as to circumscribe the pillar member 10 at the center, thereby minimizing the outer diameter of the cable.

[0043] Here, each pair of the four conductor wires 20 is configured with two conductor wires and is responsible for transmitting different Low Voltage Differential Signaling (LVDS) signals. Specifically, the four conductor wires 20 are arranged on opposite sides of the pillar member 10 disposed in the center, and each pair of two conductor wires 20a, 20b and 20c, 20d is connected to connector terminals connected to vehicle electrical components, thereby performing a communication function.

[0044] When configured in this manner, the vehicle Ethernet cable 100 of the present invention can use all four conductor wires 20 for data transmission, thereby eliminating the need for conductor wires for grounding or spare functions as in a typical UTP cable and preventing unnecessary expansion of the cable's outer diameter. Furthermore, since the vehicle Ethernet cable 100 is capable of transmitting larger amounts of data than a conventional vehicle Ethernet cable consisting of one pair of conductor wires, it is possible to reduce the number of cables laid inside the vehicle, which has the advantage of making maintenance such as organizing the cable wiring more convenient.

[0045] The four conductor wires 20 have a total cross-sectional area (mm 2 ) is 0.15~0.17mm 2 The total cross-sectional area of ​​the plurality of wires 21 (mm 2 ) is precisely adjusted so that the attenuation per unit length (m) for the 50 MHz test signal of the Ethernet cable 100 is 0.25 dB or less.

[0046] Here, attenuation is a value that measures how much the signal strength along a cable is lost and weakened when transmitted over a certain distance. If a cable has low attenuation characteristics, it can be understood that it has better transmission capabilities than a cable with high attenuation characteristics.

[0047] The sum of the cross-sectional areas (mm 2 ) is larger, the resistance of the signal and power flowing inside the conductor wire 20 is reduced, and the attenuation characteristics are improved.

[0048] The sum of the cross-sectional areas of the plurality of wires 21 (mm 2 ) is 0.15mm 2 If the total cross-sectional area of ​​the plurality of wires 21 is less than 1 / 2 mm, the attenuation characteristics of the cable will be significantly reduced. 2 If the area is greater than 0.17 mm2, the attenuation characteristics of the cable can be improved, but the conductor content in the cable increases excessively, which increases the manufacturing cost and increases the weight and outer diameter of the cable.

[0049] Preferably, each of the four conductor wires 20 is composed of seven element wires 21, and the seven element wires 21 may be arranged so that one element wire is arranged in the center and six element wires 21 are arranged around it in a circumscribing manner. In this configuration, the average diameter (mm) of each of the seven element wires 21 constituting each of the four conductor wires 20 is 0.16 to 0.18 millimeters (mm), and the total cross-sectional area of ​​the seven element wires 21 is 0.15 to 0.17 mm. 2 The range may be configured to maintain a

[0050] Each of the four conductor wires 20 is a stranded conductor formed by twisting together a plurality of strands 21 at a regular pitch. When configured as such, the conductor wires have excellent banding characteristics, are easy to install in the complex electrical space inside a vehicle, and are characterized by excellent durability.

[0051] The plurality of wires 21 constituting each of the four conductor wires 20 can be made of a metal material such as copper, aluminum, or silver, which has low resistance and good electrical conductivity, or an alloy of these metals.

[0052] The insulator 23 may be formed by extruding an insulating composition containing a polymer resin having electrical insulating properties as a base resin, and the polymer resin is not particularly limited as long as it can realize electrical insulating properties, but may be made of a material such as polypropylene (PP).

[0053] Meanwhile, in order to stably transmit high-frequency band signals using the Ethernet cable 100, it is necessary to adjust the characteristic impedance according to the input / output impedance of devices connected to the Ethernet cable. Such adjustment of the characteristic impedance can be achieved, for example, by adjusting the thickness of the insulator 23, the dielectric constant of the material of the insulator 23, the dielectric constant of the material of the pillar member 10, etc. In particular, the inventors were able to satisfy the characteristic impedance condition range of 90 to 110 ohms (Ω), which is required for the vehicle Ethernet cable 100 of the present invention, by adjusting the thickness of the insulator 23.

[0054] Specifically, as the thickness of the insulator 23 increases and the outer diameter of the conductor wire 20 increases, the capacitance of the cable tends to decrease, the attenuation tends to decrease, and the characteristic impedance value tends to increase, while as the thickness of the insulator 23 decreases and the outer diameter of the conductor wire 20 decreases, the capacitance of the cable tends to increase, the attenuation tends to increase, and the characteristic impedance value tends to decrease.

[0055] Therefore, it has been experimentally confirmed that when the thickness of the insulator 23 is formed to be 0.3 to 0.6 millimeters (mm) and the outer diameter of the conductor wire 20 due to the thickness of the insulator 23 is 1.3 to 1.7 millimeters (mm), the characteristic impedance of the vehicle Ethernet cable 100 can be configured to satisfy 90 to 110 ohms (Ω) for a 50 MHz test signal.

[0056] It has been confirmed that if the twisting pitch of the four conductor wires 20 is less than 26 mm, the length of the entire conductor wires 20 twisted together at a short twisting pitch increases, which is counter to weight reduction, and if the twisting pitch of the four conductor wires 20 exceeds 34 mm, it becomes difficult to maintain the twisting pitch due to the restoring force of the cable itself, and in particular, the effect of attenuating crosstalk between the four conductor wires 20 may decrease.

[0057] Therefore, the vehicle Ethernet cable 100 according to the present invention is characterized in that the four conductor wires 20 are twisted together at a twisting pitch of 26 to 34 mm, preferably 29 to 31 mm. When the four conductor wires 20 are twisted together at the above-mentioned pitch range, the outer diameter of the twisted four conductor wires 20 can be 3.4 to 3.8 mm.

[0058] The shielding layer 30 is a component that is provided to completely encase the four conductor wires 20, and the shielding layer 30 functions to reflect or absorb and block electromagnetic waves emitted to the outside from the four conductor wires 20 and electromagnetic waves that attempt to penetrate from the outside into the Ethernet cable 100 according to the present invention.

[0059] The shielding layer 30 may include, for example, an aluminum-mylar (Al-mylar) tape layer 31 including one or more aluminum-mylar tapes in which aluminum foil is attached to a polyester film, and / or a braided layer 33 including at least one of tin-plated copper and carbon fiber (including metal-plated carbon fiber). When the shielding layer 30 includes both the aluminum-mylar tape layer 31 and the braided layer 33, the aluminum-mylar tape layer 31 may be wound laterally to wrap around the four conductor wires 20, and the braided layer 33 may be arranged in a structure in which the aluminum-mylar tape layer 31 is wrapped around the four conductor wires 20, and the braided layer 33 is wrapped around the aluminum-mylar tape layer 31.

[0060] Here, the thickness of the aluminum-mylar tape layer 31 constituting the shielding layer 30 may be about 0.017 to 0.033 mm, and the thickness of the braided layer 33 may be about 0.08 to 0.12 mm. When the thickness of the aluminum-mylar tape layer 31 and / or the braided layer 33 constituting the shielding layer 30 is within this range, crosstalk between adjacent Ethernet cables can be appropriately blocked and an increase in the outer diameter of the Ethernet cable can be minimized.

[0061] The one or more aluminum-mylar (Al-mylar) tapes constituting the aluminum-mylar tape layer 31 are wound transversely around the four conductor wires 20 in a direction different from the twisting direction of the four conductor wires 20. In this case, the electrical characteristics of the vehicle Ethernet cable 100 of the present invention can be satisfied, as will be described later.

[0062] The outer jacket 40 is disposed to encase the shielding layer 30 and serves to protect the four conductor wires 20 from external pressure and impact.

[0063] The outer jacket 40 may be made of various polymer resin materials such as polypropylene, polyvinyl chloride, polyethylene, etc., and may be made by extruding a composition containing polypropylene resin, which has excellent heat resistance, as a base resin.

[0064] The thickness of the outer jacket 40 can be selected within the range of 0.48 to 0.68 mm. If the thickness of the outer jacket 40 is less than 0.48 mm, the cable may be broken or damaged due to external friction or bending, while if the thickness exceeds 0.68 mm, the cable flexibility may decrease and the overall outer diameter of the cable may increase. The outer diameter of the Ethernet cable of the present invention, depending on the thickness of the outer jacket 40, may be 4.5 to 6.0 mm.

[0065] FIG. 3 shows a graph of measured attenuation and near-end crosstalk (NEXT) for each strand diameter depending on the twist pitch of the four conductor wires 20 constituting the vehicle Ethernet cable 100 according to the present invention.

[0066] As described above, for stable long-distance communication based on Low Voltage Differential Signal (LVDS), the vehicular Ethernet cable 100 according to the present invention must have an attenuation per unit length (m) of 0.25 dB or less for a 50 MHz test signal.

[0067] In this specification, the attenuation of the vehicle Ethernet cable according to the present invention is measured with reference to TIA-EIA-644-A defined by the Electronic Industries Association of America and the Open Alliance, a vehicle internet system standard. The actual measured value of attenuation according to this measurement method is measured as a negative value, but since the same value is indicated as a positive value in the standard, the attenuation value measured in the present invention is indicated as a positive value.

[0068] Here, the attenuation of the cable can be adjusted by adjusting the cross-sectional area or diameter of the plurality of strands inside the conductor wire 20 to realize the desired attenuation characteristics of the cable.

[0069] The vehicle Ethernet cable 100 of the present invention was manufactured as in Comparative Example 1, Example 1, and Comparative Example 2, with the average diameter of the seven strands 21 constituting each of the four conductor wires 20 as shown in Table 1 below. The attenuation per 100 m of each cable was measured according to the twisting pitch of the four conductor wires 20, and is shown in Figure 3.

[0070] [Table 1]

[0071] 3, in Comparative Example 1, the seven strands 21 constituting each of the four conductor wires 20 had a relatively small average diameter of 0.16 mm, which increased the internal conductor resistance of the conductor wires 20. This resulted in a too large range of twist pitches for achieving an attenuation of 25 dB or less per 100 m of cable, making it impossible to manufacture a cable composed of properly twisted conductor wires. It was confirmed that the minimum twist pitches for achieving an attenuation of 25 dB or less per 100 m of cable were approximately 17.8 mm and approximately 26.4 mm for Example 1 and Comparative Example 2. As the cross-sectional area or diameter of the strands constituting the conductor wire 20 increases, the conductor resistance decreases. Therefore, it is preferable to increase the diameter of the strands in terms of the attenuation characteristics of the cable. However, the vehicle Ethernet cable 100 of the present invention aims to solve the problem of reducing the outer diameter and weight of the entire cable by minimizing the amount of conductor used, as well as improving the attenuation characteristics of the cable. Therefore, in terms of attenuation and weight reduction in the vehicle Ethernet cable of the present invention, the average diameter (mm) of the strands constituting the conductor wire should be approximately 0.17 mm. Through additional experiments, it was confirmed that the average diameter (mm) of the strands constituting the conductor wire is preferably 0.166 to 0.174 mm, taking into account margins or measurement errors.

[0072] Meanwhile, as the twisting pitch of the four conductor wires 20 completed according to Example 1 or the resulting conductor length increases, a phenomenon occurs in which communication characteristics deteriorate due to near-end crosstalk (NEXT). Here, near-end crosstalk (NEXT) refers to a phenomenon in which electrostatic or electromagnetic coupling occurs between adjacent conductors, causing a signal current in one conductor to be induced in another conductor, resulting in noise or signal interference.

[0073] In particular, the vehicle Ethernet cable 100 of the present invention, which transmits LVDS signals, must have attenuation characteristics and minimize electromagnetic interference (EMI) caused by crosstalk between adjacent pairs inside the cable. Therefore, the inventors, referring to the LVDS system standard TIA EIA 644 A defined by the Electronic Industries Association and the Open Alliance vehicle internet system standard, adjusted the twist pitch of the four conductor wires 20 so that the near-end crosstalk over a 100-meter transmission section for a 50 MHz test signal in the vehicle Ethernet cable 100 would be 50 dB or more. Similarly, while the actual measured value of attenuation using the above measurement method is measured as a negative value, the same value is indicated as a positive value in the above standard, so the attenuation value measured in the present invention is indicated as a positive value.

[0074] As shown in Figure 3, measurements of near-end crosstalk (NEXT) depending on the twist pitch of the Ethernet cable manufactured based on Example 1 confirmed that the twist pitch range for achieving a near-end crosstalk of 50 dB or more of the cable is approximately 34.2 mm or less. Therefore, it was confirmed that when the twist pitch of the four conductor wires 20 is approximately 26 to 34 mm, preferably 29 to 31 mm, the vehicle Ethernet cable 100 of the present invention can satisfy all of the attenuation and near-end crosstalk requirements.

[0075] That is, the vehicle Ethernet cable 100 according to the present invention has a cross-sectional area (mm 2) is 0.15~0.17mm 2 If the four conductor wires 20 are configured with a twisting pitch of 26 to 34 mm while satisfying the above range, the amount of conductor used can be minimized, reducing cable manufacturing costs, while minimizing the overall outer diameter and weight of the cable, improving the energy efficiency and interior space efficiency of the vehicle.

[0076] FIG. 4 shows a graph of measured return loss (RL) when the aluminum Mylar tape layer 31 of the vehicle Ethernet cable 100 according to the present invention is wound laterally in a direction different from the twisting direction of the four conductor wires 20, and FIG. 5 shows a graph of measured return loss when the aluminum Mylar tape layer 31 of the vehicle Ethernet cable 100 according to the present invention is wound laterally in the same direction as the twisting direction of the four conductor wires 20.

[0077] Specifically, for the vehicle Ethernet cable 100 of the present invention, the four conductor wires 20 were twisted together in the S direction, and the aluminum Mylar tape layer 31 was wound transversely in the S direction and Z direction, respectively, and installed on a transmission line, and the return loss was measured for each frequency (MHz) of the Ethernet cable 100.

[0078] Here, return loss refers to the degree of impedance matching between a cable and a connector. It generally refers to the structural return loss, which is the loss caused by minute vibrations that occur along the length of the cable, and the return loss of the input signal that occurs at the connection point of the cable (connector, patch cord, etc.). The smaller the return loss value, the smaller the reflection and the better the impedance matching.

[0079] As shown in FIG. 4, when the four conductor wires 20 are twisted in the S direction and an aluminum-mylar (Al-mylar) tape layer 31 is wound transversely on top of them in the Z direction, the unraveling of the aluminum-mylar tape layer 31 provided on the top of the four conductor wires 20 is minimized, the internal structure is maintained in a stable state, and a relatively small return loss value is measured.

[0080] In addition, when the aluminum mylar tape layer 31 is wound in a direction different from the twisting direction of the four conductor wires 20, it can be confirmed that the return loss values ​​measured in the entire test frequency (MHz) range have a sufficient margin compared to the return loss limit (RL limit).

[0081] Here, the return loss limit value is a value experimentally derived for the return loss of the vehicle Ethernet cable 100, and if the measured return loss value is greater than the RL Limit, the connection portion of the Ethernet cable may be damaged or the data transmission speed may decrease, resulting in an overall degradation of the performance of the LVDS system.

[0082] On the other hand, as shown in FIG. 5, if the four conductor wires 20 are twisted in the S direction and an aluminum-mylar (Al-mylar) tape is wound transversely on top of them in the S direction, various mechanical stresses such as stress and tensile force applied to the four conductor wires 20 due to bending or banding of the cable will be concentrated in specific areas of the conductor wires 20 in the transverse winding direction of the aluminum-mylar tape layer 31, resulting in a deterioration of communication characteristics. Specifically, measurement results for return loss show that there is little margin for the return loss limit in the frequency range of approximately 80 to 100 MHz, or the limit is exceeded in the high frequency range, which is likely to result in data loss or signal failure due to impedance mismatch.

[0083] Therefore, it has been confirmed that the vehicle Ethernet cable 100 according to the present invention can improve the return loss characteristics among the electrical characteristics of the cable by configuring the twisting direction of the four conductor wires 20 and the horizontal winding direction of the aluminum Mylar tape layer 31 to be different from each other.

[0084] Although the present specification has been described with reference to preferred embodiments of the present invention, those skilled in the art will be able to implement the present invention with various modifications and changes without departing from the spirit and scope of the present invention as set forth in the claims below. Therefore, any modified embodiment that basically includes the elements of the claims of the present invention should be considered to be included in the technical scope of the present invention.

Claims

1. A pillar member; Four conductor wires are arranged around the pillar member and include a plurality of wires having a total cross-sectional area of ​​0.15 to 0.17 mm2 and an insulator surrounding the plurality of wires; The four conductor wires are twisted together at a twist pitch of 26 to 34 millimeters (mm), and each pair of the four conductor wires is capable of transmitting a different Low Voltage Differential Signaling (LVDS) signal.

2. 2. The vehicle Ethernet cable according to claim 1, wherein the twist pitch of the four conductor wires is 29 to 31 millimeters (mm).

3. 2. The vehicle Ethernet cable according to claim 1, wherein the attenuation per unit length (m) of the cable for a 50 MHz test signal is 0.25 dB or less.

4. 2. The vehicle Ethernet cable according to claim 1, wherein the near-end crosstalk of the cable in a 100 meter (m) transmission section for a 50 MHz test signal is 50 dB or more.

5. 2. The vehicle Ethernet cable according to claim 1, wherein the average diameter (mm) of the plurality of strands constituting the four conductor wires is 0.16 to 0.18 millimeters (mm).

6. 2. The vehicle Ethernet cable according to claim 1, wherein each of the four conductor wires is composed of seven strands, and the seven strands are arranged such that one strand is located in the center and six strands are arranged around it so as to circumscribe it.

7. 7. The vehicle Ethernet cable according to claim 6, wherein the four conductor wires have an insulator thickness of 0.3 to 0.6 millimeters (mm) and a characteristic impedance of 90 to 110 ohms (Ω) with respect to a 50 MHz test signal.

8. 2. The vehicle Ethernet cable of claim 1, wherein the pillar member is made of at least one material selected from the group consisting of polyethylene (PE), fluorinated ethylene propylene (FEP), and polyethylene terephthalate (PET), and has an outer diameter of 0.5 to 0.6 millimeters (mm).

9. 8. The vehicle Ethernet cable according to claim 7, wherein the outer diameter of each of the four conductor wires is 1.3 to 1.7 millimeters (mm).

10. 2. The vehicle Ethernet cable according to claim 1, wherein the outer diameter of the cable is 4.5 to 6.0 millimeters (mm).

11. 2. The vehicle Ethernet cable according to claim 1, further comprising a shielding layer surrounding the four conductor wires, the shielding layer comprising an aluminum-mylar (Al-mylar) tape layer.

12. 12. The vehicle Ethernet cable according to claim 11, wherein the shielding layer includes a braided layer including at least one of tin-plated copper and carbon fiber wrapped around the aluminum-mylar (Al-mylar) tape layer.

13. 12. The vehicle Ethernet cable according to claim 11, wherein the aluminum-mylar (Al-mylar) tape layer is wound transversely in a direction different from the twisting direction of the four conductor wires.

14. 12. The vehicle Ethernet cable of claim 11, further comprising an outer jacket encasing the shielding layer.

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