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 enables large-capacity data communication and high-speed transmission required by a vehicle network system based on a Low Voltage Differential Signal (LVDS), minimizes the overall outer diameter and weight, and has excellent vibration resistance and electrical properties. [Background technology]

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

[0003] Therefore, the demand for large-volume data processing and high-speed transmission is increasing in the vehicle network system. In this regard, a low voltage differential signal (LVDS) system method capable of high-speed transmission and reducing power consumption by using a low voltage 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 at the same time 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 in vehicles.

[0005] Fig. 6 shows a cross-sectional view of an example of a conventional Ethernet cable for vehicles. As shown in Fig. 6, the conventional Ethernet cable for vehicles 100' includes a pair of conductor wires 20 including a plurality of strands 21 and an insulator 23 that encases the entire strands, twisted together with a large twist pitch, and an outer jacket 40 that encases the pair of conductor wires 20 as a whole.

[0006] Here, in the conventional Ethernet cable 100' for vehicles, a large number of Ethernet cables 100' must be provided in proportion to the types of signals to be transmitted, and the conventional Ethernet cable 100' is not adequately protected against noise caused by mutual influence between the cables. Moreover, the conventional Ethernet cable 100' for vehicles is not adequately protected against vibration and impact, and therefore cannot ensure sufficient durability as a cable for vehicles.

[0007] Furthermore, when Ethernet cables such as general UTP cables or 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 losses.

[0008] In addition, when an Ethernet cable such as a general UTP cable or STP cable is applied to a vehicle, it has a structure including four pairs in which eight conductor wires are twisted in pairs at a large twist pitch. Here, four of the eight conductor wires are usually used for grounding or as a spare, which leads to a problem of unnecessary resource consumption and increased costs.

[0009] To address these issues, there is a growing 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 an Ethernet cable for vehicles that enables large-capacity data communication and high-speed transmission required for vehicle network systems based on Low Voltage Differential Signal (LVDS), minimizes the overall outer diameter and weight, and has excellent vibration durability 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 strands and an insulator encasing the plurality of strands, 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 is made up of two strands each, and each pair is capable of transmitting 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, for a 50 MHz test signal of the cable, the attenuation per unit length (m) can be satisfied to 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 mm.

[0016] In this case, each of the four conductor wires is composed of seven strands, and the seven strands may be arranged such that one strand is disposed in the center and six strands are circumscribing the central strand.

[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 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, the shielding layer including an aluminum-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 tape layer.

[0023] The aluminum-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 encasing the shielding layer. Effect of the Invention

[0025] According to the vehicle Ethernet cable of the present invention, the twist pitch of the four conductor wires is adjusted to minimize signal and power loss, enabling large-capacity data communication and high-speed transmission required by vehicle network systems based on Low Voltage Differential Signal (LVDS).

[0026] In addition, according to the vehicle Ethernet cable of the present invention, the cross-sectional area (mm 2 ) can minimize the amount of conductor used, reducing cable manufacturing costs, and can improve the energy efficiency and interior space efficiency of the vehicle by minimizing the overall outer diameter and weight of the cable.

[0027] In addition, according to the vehicle Ethernet cable of the present invention, by locating 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 Ethernet cable for vehicles of the present invention, the twisting direction of the four conductor wires and the transverse winding direction of the shielding layer are configured to be different from each other, thereby improving the return loss among the electrical characteristics and smoothly implementing impedance matching of the Ethernet cable even in a high-speed transmission environment. [Brief description of the drawings]

[0029] [Figure 1] FIG. 2 is a perspective view of a vehicle Ethernet cable according to the present invention in a multi-stage stripped state. [Diagram 2] 1 is a cross-sectional view of a vehicle Ethernet cable according to the present invention. [Diagram 3] 1 is a graph showing the results of measuring attenuation and near-end crosstalk for each diameter of wires depending on the twist pitch of the four conductor wires constituting the vehicle Ethernet cable according to the present invention. [Figure 4] 13 is a graph showing measured return loss when an aluminum-Mylar tape layer of an Ethernet cable for vehicles according to the present invention is wound transversely in a direction different from the twisting direction of four conductor wires. [Diagram 5] 11 is a graph showing measured return loss when an aluminum-Mylar tape layer of an Ethernet cable for vehicles according to the present invention is wound transversely in the same direction as the twisting direction of four conductor wires. [Figure 6] FIG. 1 is a cross-sectional view of a conventional vehicle Ethernet cable. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiment 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 will fully convey the concept of the invention 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] In order to realize the infotainment functions of such 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. For such vehicle cables, the amount of data transmitted is larger than before, and it is necessary to apply cables that can communicate at high speed.

[0033] In such an environment where high-speed data transmission is required within a vehicle, the Low Voltage Differential Signals (LVDS) method can be applied. This is capable of supporting high bandwidth at low voltage and transmitting gigabit-sized large capacity data by using high-speed analog circuit technology. In particular, since the main power supply voltage of an automobile is a relatively low voltage of DC12V or DC24V, the application of LVDS has technical and economic advantages in constructing 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 in order to transmit data while maintaining sufficient voltage and waveform, and must be configured to minimize electromagnetic interference (EMI) between adjacent Ethernet cables or internal conductors.

[0035] In addition, the use of Ethernet cables for vehicles connected to various electrical components inside the vehicle is increasing, so they must be lightweight and have sufficient durability to minimize the increase in the vehicle load. In addition, there is a demand to minimize mutual influences such as noise between adjacent cables.

[0036] Therefore, an object of the present invention is to provide an Ethernet cable for vehicles that is configured to facilitate large-capacity data communication and high-speed transmission required by a vehicle network system based on a Low Voltage Differential Signal (LVDS), has a minimized 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 exterior 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 FIG. 1 and FIG. 2, a vehicle Ethernet cable 100 according to the present invention is arranged around a 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 plurality of 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). Each pair of the four conductor wires 20, each of which is composed 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 to maintain the circularity of the cable and to protect the four conductor wires 20 against mechanical vibrations of the vehicle and other external forces during installation of the Ethernet cable 100.

[0040] The pillar member 10 may be made of various polymer resins, for example, polyethylene (PE), fluorinated ethylene propylene (FEP), polyethylene terephthalate (PET), polyvinyl chloride (PVC), polypropylene (PP), etc., and is preferably made of at least one of polyethylene (PE), fluorinated ethylene propylene (FEP), and polyethylene terephthalate (PET). Here, when the pillar member 10 is made of polyethylene terephthalate (PET), it has a relatively high hardness, and it is possible to minimize or prevent the pillar member 10 from elongating during cable manufacture.

[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, unnecessarily increasing 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 which 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 composed of two conductor wires and can transmit different low voltage differential signals (LVDS). Specifically, the four conductor wires 20 are arranged on the opposite side of the pillar member 10 arranged in the center, and each pair of the pairs, each composed of two conductor wires 20a, 20b and 20c, 20d, can be connected to connector terminals connected to vehicle electrical components to perform 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 omitting conductor wires for grounding or spare function as in general UTP cables, thereby preventing unnecessary expansion of the outer diameter of the cable.In addition, while enabling larger volumes of data transmission than when using a conventional vehicle Ethernet cable including one conductor wire pair, the number of cables laid inside the vehicle can be reduced, resulting in convenient maintenance such as organizing the cable wiring.

[0045] The four conductor wires 20 have a total cross-sectional area (mm 2 ) is 0.15~0.17mm 2 The conductor may be a stranded conductor including a plurality of wires 21. Here, the sum of the cross-sectional areas 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 measurement of how much the signal strength traveling along a cable is lost and weakened when it is transmitted over a certain distance. If a cable has low attenuation characteristics, it can be understood to have 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 characteristic is improved.

[0048] The sum of the cross-sectional areas of the plurality of wires 21 (mm 2 ) is 0.15 mm 2 If the total cross-sectional area of ​​the plurality of wires 21 is less than 1 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, resulting in high manufacturing costs and an increase in the weight and outer diameter of the cable.

[0049] Preferably, each of the four conductor wires 20 is composed of seven strands 21, and the seven strands 21 may be arranged such that one strand is arranged in the center and six strands 21 are arranged around it. When configured in this manner, the average diameter (mm) of each of the seven strands 21 constituting each of the four conductor wires 20 is 0.16 to 0.18 millimeters (mm), and the sum of the cross-sectional areas of the seven strands 21 is 0.15 to 0.17 mm. 2 The range may be configured to maintain.

[0050] Each of the four conductor wires 20 is a stranded conductor in which a plurality of wires 21 are stranded at a constant pitch. When configured as such, the conductor wires have excellent banding characteristics, are easy to install in the complex electrical equipment space inside a vehicle, and have excellent durability.

[0051] The multiple strands 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 including a polymer resin having electrical insulating properties as a base resin, and the polymer resin is not particularly limited as long as it can embody electrical insulating properties, and may be made of a material such as polypropylene (PP).

[0053] Meanwhile, in order to stably transmit a high frequency band signal using the Ethernet cable 100, it is necessary to adjust the characteristic impedance according to the input / output impedance of a device 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 present inventors were able to satisfy the characteristic impedance condition range of 90 to 110 ohms (Ω) 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 aforementioned pitch range, the outer diameter of the twisted four conductor wires 20 may be 3.4 to 3.8 mm.

[0058] The shielding layer 30 is a component provided to wrap the entire 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 attempting to penetrate from the outside into the Ethernet cable 100 according to the present invention.

[0059] The shielding layer 30 may include 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 transversely to wrap 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 aluminum-Mylar tape layer 31 constituting the shielding layer 30 may have a thickness of about 0.017 to 0.033 mm, and the braided layer 33 may have a thickness of 0.08 to 0.12 mm. When the aluminum-Mylar tape layer 31 and / or the braided layer 33 constituting the shielding layer 30 have a thickness within the above 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] 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, which 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 preferably made by extruding a composition containing polypropylene resin having excellent heat resistance as a base resin.

[0064] The thickness of the outer jacket 40 may 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 flexibility of the cable may decrease and the overall outer diameter of the cable may increase. The outer diameter of the Ethernet cable of the present invention according to the thickness of the outer jacket 40 may be 4.5 to 6.0 mm.

[0065] FIG. 3 is a graph showing the results of measuring the attenuation and near-end crosstalk (NEXT) for each diameter of the strands according to the twist pitch of the four conductor wires 20 constituting the Ethernet cable for vehicles 100 according to the present invention.

[0066] As described above, in order to achieve stable long-distance communication based on a Low Voltage Differential Signal (LVDS), the Ethernet cable 100 for a vehicle 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 and the Open Alliance, a vehicle internet system standard. The actual measured value of the attenuation according to the above measurement method is measured with a negative sign, but since the same value is shown with a positive sign in the above standard, the attenuation value measured in the present invention is shown with a positive sign.

[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 attenuation characteristics required for 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 according to 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 according to the twist pitch of the four conductor wires 20 was measured and shown in FIG. 3.

[0070] [Table 1]

[0071] 3, in Comparative Example 1, the seven strands 21 constituting each of the four conductor wires 20 have a relatively small average diameter of 0.16 mm, and the internal conductor resistance of the conductor wires 20 increases, so the range of twist pitches for achieving an attenuation of 25 dB or less per 100 m of cable is too wide, making it impossible to manufacture a cable made 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 are about 17.8 mm and about 26.4 mm in 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, and therefore it is preferable to increase the diameter of the strands in terms of the attenuation characteristics of the cable. However, the Ethernet cable 100 for vehicles of the present invention aims to solve the problem of reducing the outer diameter and weight of the entire cable by configuring the cable to minimize the amount of conductor used as well as the attenuation characteristics of the cable. Therefore, in the Ethernet cable for vehicles of the present invention, in terms of attenuation and weight reduction, the average diameter (mm) of the multiple strands constituting the conductor wire should be approximately 0.17 mm, and additional experiments have confirmed that the average diameter (mm) of the multiple strands constituting the conductor wire is preferably 0.166 to 0.174 mm, taking into account margins or measurement errors.

[0072] Meanwhile, as the twist pitch of the four conductor wires 20 completed according to the first embodiment or the length of the conductors increases, a phenomenon occurs in which communication characteristics are degraded due to near-end crosstalk. Here, near-end crosstalk (NEXT) refers to a phenomenon in which electrostatic or electromagnetic coupling occurs between adjacent conductors, and a signal current in one conductor is induced in another conductor, causing noise or signal interference.

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

[0074] 3, the near-end crosstalk (NEXT) of the Ethernet cable manufactured based on Example 1 was measured according to the twist pitch, and it was confirmed that the twist pitch range for the cable to satisfy the near-end crosstalk of 50 dB or more is about 34.2 mm or less. Therefore, it was confirmed that when the twist pitch of the four conductor wires 20 is about 26 to 34 mm, preferably when the twist pitch of the four conductor wires 20 is 29 to 31 mm, all of the attenuation and near-end crosstalk conditions of the vehicle Ethernet cable 100 of the present invention can be satisfied.

[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 When the four conductor wires 20 are configured with a twist pitch of 26 to 34 mm while satisfying the above range, the amount of conductor used can be minimized, reducing cable manufacturing costs, while the overall outer diameter and weight of the cable can be minimized, improving the energy efficiency and interior space efficiency of the vehicle.

[0076] FIG. 4 shows a graph measuring the return loss (RL) when the aluminum Mylar tape layer 31 of the Ethernet cable for vehicles 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 measuring the return loss when the aluminum Mylar tape layer 31 of the Ethernet cable for vehicles 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 tape layer 31 is wound transversely on top of the four conductor wires 20 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 the return loss value is measured to be relatively small.

[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 value measured in the entire test frequency (MHz) range has a sufficient margin compared to the return loss limit (RL limit).

[0081] Here, the return loss limit value is an experimentally derived value 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, when 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 as shown in FIG. 5, various mechanical stresses such as stress and tensile force applied to the four conductor wires 20 due to bending or banding of the cable are concentrated in specific areas of the conductor wires 20 in the transverse winding direction of the aluminum-mylar tape layer 31, degrading the communication characteristics. Specifically, the measurement results of the return loss show that there is a small margin for the return loss limit in the frequency range of about 80 to 100 MHz, or the limit is exceeded in the high frequency range, which is thought to result in data loss and 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 characteristic, among the electrical characteristics of the cable, by configuring the twisting direction of the four conductor wires 20 and the transverse 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 the preferred embodiment of the present invention, those skilled in the art will be able to implement the present invention in various modifications and alterations without departing from the spirit and scope of the present invention as described 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; The pillar member is disposed around the pillar member, and the total cross-sectional area is 0.15 to 0.17 mm ２ Four conductor wires each including a plurality of wires each having a thickness of 100 nm 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 different low voltage differential signaling (LVDS).

2. 2. The vehicle Ethernet cable according to claim 1, wherein the twist pitch of the four conductor wires is preferably 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 an average diameter (mm) of the multiple 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 disposed in the center and six strands are disposed around it in a circumscribing manner.

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

8. 2. The vehicle Ethernet cable according to 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 of 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 of 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 tape layer.

13. 12. The vehicle Ethernet cable according to claim 11, wherein the aluminum-mylar tape layer is transversely wound in a direction different from a 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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