Cable connection structure

Abstract

Provided is a cable connection structure that makes it possible to adjust characteristic impedance to a predetermined value over the entire length of communication conductors including a connection part. A first cable 10 has, on a side thereof having an end portion that connects to a second cable 20, a first processing part 10a formed to be processed when the first cable 10 is connected to the second cable 20. The second cable 20 has, on a side thereof having an end portion that connects to the first cable 10, a second processing part formed to be processed when the second cable 20 is connected to the first cable 10. A connection part 30 is disposed between a base end portion of the first processing part 10a of the first cable 10 and a base end portion of the second processing part 20a of the second cable 20 in a state where the first cable 10 and the second cable 20 are connected to each other. The dimension of the connection part 30 in the extending direction of conductors 11, 21, 32 is less than or equal to a predetermined dimension set on the basis of the communication speed of data communication using the conductors 11, 21, 32.

Description

Cable connection structure

[0001] The present invention relates to a cable connection structure used for connecting one cable to another cable.

[0002] Conventionally, there has been known a cable connection structure for connecting a first cable including at least a pair of communication conductors and a second cable including at least a pair of communication conductors, in which the communication conductor included in the first cable is electrically directly connected to the communication conductor included in the second cable (see, for example, Patent Document 1).

[0003] For a cable including communication conductors, it is necessary to adjust the characteristic impedance to a predetermined value over the entire length of the communication conductors, particularly in order to stabilize communication performance in high-speed communication. For this reason, in a cable including communication conductors, characteristic impedance is adjusted to a predetermined value by forming a metal layer at a predetermined interval from the communication conductors.

[0004] Japanese Patent No. 3170189

[0005] However, when joining a plurality of cables each including communication conductors, the metal layer and insulation coating on the end side of each cable are removed to connect the communication conductors to each other. For this reason, at the connection portion where cables are connected to each other, the characteristic impedance deviates from the predetermined value, which may result in a state where the characteristic impedance cannot be adjusted to the predetermined value over the entire length of the communication conductors.

[0006] An object of the present invention is to provide a cable connection structure capable of adjusting the characteristic impedance to a predetermined value over the entire length of the communication conductors including the connection portion.

[0007] The cable connection structure according to the present invention is a cable connection structure for connecting a first cable including at least one pair of first communication conductors and a second cable including at least one pair of second communication conductors, wherein the first communication conductors are electrically connected to the second communication conductors, the first cable and the second cable are each different types of cables, a first processed portion is formed on the end of the first cable that is connected to the second cable, a second processed portion is formed on the end of the second cable that is connected to the first cable, a connection portion is arranged between the base end of the first processed portion of the first cable and the base end of the second processed portion of the second cable when the first cable and the second cable are connected, and the size of the first communication conductor and the second communication conductor in the extending direction at the connection portion is less than or equal to a predetermined size set based on the communication speed of data communication using the first communication conductor and the second communication conductor.

[0008] Furthermore, in the cable connection structure according to the present invention, it is preferable that the first cable or the second cable is a flat cable in which a plurality of conductors are arranged at intervals from each other.

[0009] Furthermore, in the cable connection structure according to the present invention, it is preferable that the first cable or the second cable is a twisted cable in which a plurality of conductors are twisted together.

[0010] Furthermore, in the cable connection structure according to the present invention, it is preferable that the first cable or the second cable is a coaxial cable in which one conductor is arranged on the outer circumference of the other conductor.

[0011] Furthermore, the cable connection structure according to the present invention preferably includes a connecting member for connecting the first communication conductor and the second communication conductor, wherein the connecting member has a pair of connecting conductors that electrically connect each of the pair of first communication conductors to each of the pair of second communication conductors, and an insulating portion that holds the pair of connecting conductors.

[0012] Furthermore, in the cable connection structure according to the present invention, it is preferable that the connecting conductor extends in a bent state while being held by the insulating portion.

[0013] Furthermore, it is preferable that the cable connection structure according to the present invention has a ground conductor that is connected to the ground.

[0014] According to the present invention, by setting the size of the communication conductor in the extension direction of the connection portion to a predetermined size or less based on the data communication speed, it is possible to suppress deviations of the characteristic impedance at the connection portion from a predetermined value, and to adjust the characteristic impedance to a predetermined value over the entire length of the conductor used for data communication, including the connection portion.

[0015] Figure 1 is a schematic plan view of a cable connection structure according to the first embodiment of the present invention. Figure 2 is a diagram illustrating the characteristic impedance that changes according to the communication speed in the cable connection structure according to the first embodiment of the present invention. Figure 3 is a diagram illustrating the characteristic impedance that changes according to the size of the connection part in the cable connection structure according to the first embodiment of the present invention. Figure 4 is a diagram illustrating the characteristic impedance that changes according to the size of the connection part in a connection part without a connecting member in the cable connection structure according to the second embodiment of the present invention. Figure 5 is a schematic plan view of a connecting member according to the third embodiment of the present invention. Figure 6 is a schematic plan view of a connecting member according to the fourth embodiment of the present invention. Figure 7 is a schematic plan view of a connecting member according to the fifth embodiment of the present invention. Figure 8 is a schematic plan view of a connecting member according to the sixth embodiment of the present invention. Figure 9 is a schematic plan view of a connecting member according to the seventh embodiment of the present invention. Figure 10 is a schematic plan view of a connecting member according to the eighth embodiment of the present invention. Figure 11 is a schematic plan view of a connecting member according to the ninth embodiment of the present invention. Figure 12 is a schematic plan view of a cable connection structure according to the tenth embodiment of the present invention. Figure 13 is a schematic plan view of a cable connection structure with a shield formed according to the eleventh embodiment of the present invention. Figure 14 is a cross-sectional view taken along line A-A of Figure 13 according to the eleventh embodiment of the present invention. Figure 15 is a cross-sectional view taken along line B-B of Figure 13 according to the 11th embodiment of the present invention. Figure 16 is a schematic plan view of a cable connection structure with a shield formed according to the 12th embodiment of the present invention. Figure 17 is a cross-sectional view taken along line A-A of Figure 16 according to the 12th embodiment of the present invention. Figure 18 is a cross-sectional view taken along line B-B of Figure 16 according to the 12th embodiment of the present invention. Figure 19 is a schematic cross-sectional view of the second cable side of the connecting member 31 according to the 13th embodiment of the present invention. Figure 20 is a schematic cross-sectional view of the first cable side of the connecting member 31 according to the 13th embodiment of the present invention. Figure 21 is a schematic plan view showing another example of the cable connection structure of the present invention. Figure 22 is a schematic plan view showing another example of the cable connection structure of the present invention. Figure 23 is a schematic plan view showing another example of the cable connection structure of the present invention.Figure 24 is a graph showing the results of a test to determine whether the characteristic impedance can be maintained within a predetermined range in relation to the length of the conductor in the extending direction and the communication speed in the connection part according to the 14th embodiment of the present invention.

[0016] <First Embodiment> Figures 1 to 3 show a first embodiment of the present invention. Figure 1 is a schematic plan view of a cable connection structure. Figure 2 is a diagram illustrating the characteristic impedance that changes according to the communication speed in the cable connection structure. Figure 3 is a diagram illustrating the characteristic impedance that changes according to the size of the connection part in the cable connection structure.

[0017] The cable connection structure 1 of the present invention includes a first cable 10, a second cable 20, and a connection portion 30 formed between the first cable 10 and the second cable 20. Here, the first cable 10 and the second cable 20 are each different types of cables.

[0018] The first cable 10 and the second cable 20 are applied to movable parts such as a steering roll connector, which is a rotary connector provided at the connection point between the steering column on the vehicle body side and the steering shaft on the steering wheel side in a vehicle, a sliding door harness provided at the connection point between the vehicle body side and the sliding door, and a sliding seat harness provided at the connection point between the vehicle body side and the sliding seat, or to stationary parts such as the inside of an ECU or connections between ECUs. Furthermore, the first cable 10 and the second cable 20 are not limited to vehicles and can be applied to devices that need to communicate between one device and another.

[0019] The first cable 10 is a flat cable in which a pair of first communication conductors 11 are arranged at intervals from each other, and the pair of first communication conductors 11 are covered with an insulating material. In addition to the pair of first communication conductors 11, the first cable 10 may also include other conductors, such as a power supply conductor. The first cable 10 has a characteristic impedance adjustment section (not shown) arranged at a predetermined interval from the pair of first communication conductors 11, and the characteristic impedance is adjusted to a predetermined value (for example, 100 Ω) along its entire length. At the end of the first cable 10 that is connected to the second cable 20, a first processing section 10a is formed which is processed when connecting to the second cable 20. The first processing section 10a is the portion at the end of the first cable 10 in which the pair of first communication conductors 11 are exposed by removing the covering of the insulating material.

[0020] The second cable 20 is a twisted pair cable in which a pair of second communication conductors 21, each covered with an insulating material, are twisted together. In addition to the pair of second communication conductors 21, the second cable 20 may also include other conductors, such as a power supply conductor. The second cable 20 has characteristic impedance adjustment sections (not shown) arranged at intervals on the outer circumference of the pair of second communication conductors 21, and the characteristic impedance is adjusted to a predetermined value (for example, 100 Ω) along its entire length. A second processing section 20a is formed at the end of the second cable 20 that is connected to the first cable 10, and is processed when connected to the first cable 10. The second processing section 20a at the end of the second cable 20 includes a portion where the pair of second communication conductors 21 are exposed by removing the insulating material's covering, and a portion where the twist of the pair of second communication conductors 21 has been undone.

[0021] The pair of first communication conductors 11 of the first cable 10 and the pair of second communication conductors 21 of the second cable 20 constitute part of a communication circuit for transmitting electrical signals between one device and another. Here, the communication circuit is used for signal transmission in communication standards such as LVDS (Low Voltage Differential Signaling), which uses low voltage and low amplitude signals for high-speed transmission, CAN (Controller Area Network), CAN FD (Flexible Data Rate), CAN XL (Extra Long), and Ethernet. The transmission speed of the communication signals transmitted through the pair of first communication conductors 11 and the pair of second communication conductors 21 is generally 100 Mbps or less, but may be faster than 100 Mbps if necessary. The communication circuit may be a single-ended transmission consisting of one signal line and one ground line.

[0022] The connecting portion 30 is the portion located between the base end of the first processed portion 10a of the first cable 10 and the base end of the second processed portion 20a of the second cable 20 when the first cable 10 and the second cable 20 are connected. The connecting portion 30 consists of the first processed portion 10a, the second processed portion 20a, and the connecting member 31.

[0023] The connecting member 31 has a pair of connecting conductors 32 that connect each of the pair of first communication conductors 11 to each of the pair of second communication conductors 21, and an insulating portion 33 that holds the pair of connecting conductors 32. The connecting member 31 is preferably flexible and able to bend when subjected to external force.

[0024] Each of the pair of connecting conductors 32 is made of a conductive metal. The pair of connecting conductors 32 may also be conductors arranged on a printed circuit board. The pair of connecting conductors 32 electrically connect each of the pair of first communication conductors 11 to each of the pair of second communication conductors 21. The connections between the first communication conductors 11 and the connecting conductors 32, and between the second communication conductors 21 and the connecting conductors 32, are made by brazing, soldering, or the like.

[0025] The insulating portion 33 is made of a sheet-like material made of resin such as PET resin, and a pair of connecting conductors 32 are sandwiched between a pair of sheet-like materials.

[0026] Here, the size of the conductors 11, 21, and 32 in the extension direction at the connection portion 30 is less than or equal to a predetermined size set based on the communication speed of data communication using the first communication conductor 11 and the second communication conductor 21.

[0027] More specifically, the first processed portion 10a, the second processed portion 20a, and the connecting member 31 that constitute the connection portion 30 are parts whose characteristic impedance has not been adjusted. That is, in the connection portion 30, it may not be possible to maintain the characteristic impedance within a predetermined range. For this reason, it is preferable that the size of the conductors 11, 21, and 32 in the extension direction in the connection portion 30 be as small as possible in order to maintain the characteristic impedance in the connection portion 30 within a predetermined range.

[0028] Furthermore, the data communication speed in a communication conductor is obtained by multiplying the frequency and wavelength of the transmitted signal. The data communication speed in a communication conductor varies depending on the encoding of the communication standard, but the frequency of the transmitted signal is the maximum value of the communication speed. In this case, the size of the conductors 11, 21, and 32 in the extension direction at the connection 30 can be set, for example, to be less than or equal to one-quarter of the wavelength of the transmitted signal, thereby suppressing the occurrence of reflection and attenuation of the transmitted signal at the connection 30. Also, when setting the size of the conductors 11, 21, and 32 in the extension direction at the connection 30, a correction term that takes into account wavelength shortening, where the wavelength of the transmitted signal changes depending on the medium through which the transmitted signal propagates, may be provided. For example, when a transmitted signal propagates through a resin material with a relative permittivity of 3.4, the wavelength of the transmitted signal is 1 / √3.4 = 0.54 times that of when it propagates in a vacuum. In this embodiment, the relative permittivity of the medium through which the transmitted signal propagates is assumed to be 3.4. As a result, the length of the conductors 11, 21, and 32 in the extension direction at the connection section 30 was set to a maximum of 50 mm when the communication speed was 100 Mbps. Furthermore, the length of the conductors 11, 21, and 32 in the extension direction at the connection section 30 was set to a maximum of 5 mm when the communication speed was 1 Gbps.

[0029] In the cable connection structure 1 configured as described above, the characteristic impedances of the first communication conductor 11 of the first cable 10 and the second communication conductor 21 of the second cable 20 are adjusted to a predetermined range, such as 100Ω ± 10Ω. Furthermore, the characteristic impedance of the conductor of the connection part 30 located between the first cable 10 and the second cable 20 is also required to be adjusted to the same magnitude as the characteristic impedances of the first communication conductor 11 of the first cable 10 and the second communication conductor 21 of the second cable 20.

[0030] Figure 2 shows the results of measuring the characteristic impedance of the first communication conductor 11 of the first cable 10, the second communication conductor 21 of the second cable 20, and the conductor of the connection part 30 for the first cable 10 and the second cable 20 having the cable connection structure 1, for the cases where the communication speed is 100 Mbps and 1 Gbps or higher, respectively. Here, the extensional size of the conductors 11, 21, and 32 in the connection part 30 is set to 50 mm based on a transmission signal with a frequency of 100 MHz and a wavelength of 3 m.

[0031] Characteristic impedance was measured using the Time Domain Reflectometry (TDR) method with a network analyzer. The TDR method involves injecting a step wave into the first cable 10 and the second cable 20, which have a cable connection structure 1, and measuring the amplitude and phase of the reflected wave. In measuring the characteristic impedance, the rise time was varied according to the specifications of each communication speed, and pass / fail was determined based on the characteristic impedance threshold corresponding to the specifications of each communication speed.

[0032] In Figure 2, the characteristic impedances of the first communication conductor 11 of the first cable 10 and the second communication conductor 21 of the second cable 20 are adjusted to within the range of 100Ω ± 10Ω.

[0033] In the first cable 10 and the second cable 20, the characteristic impedances of the first communication conductor 11 and the second communication conductor 21 are maintained within the range of ±10 Ω of 100 Ω, even when the communication speed is 100 Mbps and 1 Gbps or higher, respectively.

[0034] Furthermore, in the connection section 30, when the communication speed is 100 Mbps, the characteristic impedance of the conductor is maintained within the range of ±10 Ω of 100 Ω. On the other hand, when the communication speed is 1 Gbps, there are parts where the characteristic impedance of the conductor in the connection section 30 falls outside the range of ±10 Ω of 100 Ω. In other words, it was confirmed that the cable connection structure 1 shown in Figure 2 maintains communication performance when the communication speed is 100 Mbps because the characteristic impedance of the conductor in the connection section 30 falls within a predetermined range. On the other hand, it was confirmed that the cable connection structure 1 shown in Figure 2 may experience a decrease in communication performance when the communication speed is 1 Gbps because the characteristic impedance of the conductor in the connection section 30 falls outside the predetermined range.

[0035] Furthermore, Figure 3 shows the results of measuring the characteristic impedance of the first cable 10, the second cable 20, and the connection part 30 for the first cable and the second cable 20 having the cable connection structure 1, when the communication speed is 100 Mbps, and the dimensions of the conductors 11, 21, and 32 in the extension direction at the connection part 30 are 40 mm and 80 mm, respectively. Here, the transmitted signal has a frequency of 100 MHz and a wavelength of 3 m.

[0036] In Figure 3, the characteristic impedances of the first cable 10 and the second cable 20 are adjusted to within the range of 100Ω ± 10Ω.

[0037] Furthermore, in the connection section 30, when the extension length of the conductors 11, 21, and 32 in the connection section 30 is 40 mm, the characteristic impedance is maintained within the range of ±10 Ω of 100 Ω. On the other hand, when the extension length of the conductors 11, 21, and 32 in the connection section 30 is 80 mm, there are parts where the characteristic impedance of the connection section 30 falls outside the range of ±10 Ω of 100 Ω. In other words, it was confirmed that in the cable connection structure 1 shown in Figure 3, when the extension length of the conductors 11, 21, and 32 in the connection section 30 is 40 mm, the characteristic impedance in the connection section 30 falls within a predetermined range, thus maintaining communication performance. On the other hand, it was confirmed that in the cable connection structure 1 shown in Figure 3, when the extension length of the conductors 11, 21, and 32 in the connection section 30 is 80 mm, the characteristic impedance in the connection section 30 falls outside a predetermined range, potentially leading to a decrease in communication performance.

[0038] As described above, the cable connection structure of this embodiment provides a cable connection structure 1 for connecting a first cable 10 including at least a pair of first communication conductors 11 and a second cable 20 including at least a pair of second communication conductors 21, wherein the first communication conductors 11 are electrically connected to the second communication conductors 21, the first cable 10 and the second cable 20 are each different types of cables, and the end of the first cable 10 that connects to the second cable 20 has a first processed portion 10a that is processed when connecting to the second cable 20. The second cable 20 is constructed such that a second processed portion 20a is formed at the end of the second cable 20 that is connected to the first cable 10, and a connection portion 30 is positioned between the base end of the first processed portion 10a of the first cable 10 and the base end of the second processed portion 20a of the second cable 20 when the first cable 10 and the second cable 20 are connected, and the size of the conductors 11, 21, and 32 in the extending direction at the connection portion 30 is less than or equal to a predetermined size set based on the communication speed of data communication using the conductors 11, 21, and 32.

[0039] With this configuration, by setting the size of the connecting portion 30 in the extending direction of the conductors 11, 21, and 32 to be equal to or less than a predetermined size set based on the communication speed of data communication, it is possible to suppress deviation of the characteristic impedance at the connecting portion 30 from a predetermined value, and the characteristic impedance can be adjusted to the predetermined value over the entire length of the conductor used for data communication including the connecting portion 30.

[0040] It is also preferable that the first cable 10 is a flat cable in which a plurality of first communication conductors 11 are arranged spaced apart from each other.

[0041] It is also preferable that the second cable 20 is a twisted cable formed by twisting a plurality of second communication conductors 21 together.

[0042] With this configuration, different types of the first cable 10 and the second cable 20 can be reliably connected via the connecting portion 30.

[0043] It is also preferable that the cable connection structure comprises a connecting member 31 that connects the first cable 10 and the second cable 20, and the connecting member 31 includes a pair of connecting conductors 32 that electrically connect each of the pair of first communication conductors 11 to each of the pair of second communication conductors 21, and an insulating portion 33 that holds the pair of connecting conductors 32.

[0044] With this configuration, the first communication conductors 11 and the second communication conductors 21, which have different shapes from each other, can be easily connected via the connecting member 31.

[0045] <Second Embodiment> Fig. 4 shows a second embodiment of the present invention. Fig. 4 is a diagram for explaining characteristic impedance that changes according to the size of a connecting portion in a connecting portion that does not include a connecting member in a cable connection structure.

[0046] As shown in Fig. 4, the connecting portion 30 of the cable connection structure 1 of the present embodiment directly and electrically connects each of the pair of first communication conductors 11 to each of the pair of second communication conductors 21 to each other by brazing, soldering, or the like, without via the connecting member 31.

[0047] As in the first embodiment, the connecting portion 30 is a portion positioned between the base end of the first processed portion 10a of the first cable 10 and the base end of the second processed portion 20a of the second cable 20 in a state where the first cable 10 and the second cable 20 are connected. The connecting portion 30 in the present embodiment consists of the first processed portion 10a and the second processed portion 20a.

[0048] In the cable connection structure 1 configured as described above, the characteristic impedance of the first communication conductor 11 of the first cable 10 and the characteristic impedance of the second communication conductor 21 of the second cable 20 are each adjusted to fall within a range of a predetermined value, for example, 100Ω±5Ω. It is also required that the characteristic impedance of the conductor of the connecting portion 30 positioned between the first cable 10 and the second cable 20 be adjusted to the same value as the characteristic impedance of the first communication conductor 11 of the first cable 10 and the second communication conductor 21 of the second cable 20.

[0049] FIG. 4 shows the results of measuring the characteristic impedance of the first communication conductor 11 of the first cable 10, the second communication conductor 21 of the second cable 20, and the conductors 11, 21 of the connecting portion 30, for the first cable 10 and the second cable 20 including the cable connection structure 1, when the communication speed is 1 Gbps and the dimension of the conductors 11, 21 in the extending direction at the connecting portion 30 is 5 mm and 8 mm, respectively. Here, the transmitted signal has a frequency of 1 GHz and a wavelength of 0.3 m.

[0050] In FIG. 4, the characteristic impedance of the first communication conductor 11 of the first cable 10 and the second communication conductor 21 of the second cable 20 is adjusted within a range of 100Ω±5Ω.

[0051] In the first cable 10 and the second cable 20, even when the communication speed is 1 Gbps or higher, the characteristic impedance of the first communication conductor 11 and the second communication conductor 21 is maintained within a range of ±5Ω of 100Ω.

[0052] On the other hand, the characteristic impedance of the conductors 11 and 21 in the connection section 30 falls outside the range of ±5Ω of 100Ω when the communication speed is 1Gbps and the extension length of the conductors 11 and 21 in the connection section 30 is 8mm. In other words, it was confirmed that the cable connection structure 1 in which the extension length of the conductors 11 and 21 in the connection section 30 is 8mm may experience a decrease in communication performance at a communication speed of 1Gbps. Furthermore, it was confirmed that the characteristic impedance of the conductors 11 and 21 in the connection section 30 can be maintained within the range of ±5Ω of 100Ω when the communication speed is 1Gbps and the extension length of the conductors 11 and 21 in the connection section 30 is 5mm, and that the decrease in communication performance may be suppressed.

[0053] Thus, according to the cable connection structure of this embodiment, similar to the first embodiment, by making the size of the conductors 11 and 21 in the extension direction at the connection portion 30 less than or equal to a predetermined size, it is possible to suppress deviation of the characteristic impedance at the connection portion 30 from a predetermined value, and to adjust the characteristic impedance to a predetermined value over the entire length of the communication conductor including the connection portion.

[0054] <Third Embodiment> Figure 5 shows a third embodiment of the present invention and is a schematic plan view of the connecting member. Components similar to those in the first embodiment are denoted by the same reference numerals.

[0055] As shown in Figure 5, the cable connection structure 1 of this embodiment is formed such that the dimensions of the pair of connecting conductors 32 of the connecting member 31 are different from each other in the extending direction.

[0056] In the cable connection structure 1 configured as described above, even when the extending dimensions of a pair of connecting conductors 32 are different from each other, deviations from a predetermined value of characteristic impedance at the connection part 30 are suppressed when the extending dimensions of the conductors 11, 21, and 32 at the connection part 30 are less than or equal to a predetermined size set based on the communication speed of data communication using the conductors 11, 21, and 32.

[0057] Thus, according to the cable connection structure of this embodiment, similar to the first embodiment, by making the size of the conductors 11, 21, and 32 in the extension direction of the connection portion 30 less than or equal to a predetermined size, it is possible to suppress deviation of the characteristic impedance at the connection portion 30 from a predetermined value, and to adjust the characteristic impedance to a predetermined value over the entire length of the communication conductor including the connection portion.

[0058] <Fourth Embodiment> Figure 6 shows a fourth embodiment of the present invention and is a schematic plan view of the connecting member. Components similar to those in the first embodiment are denoted by the same reference numerals.

[0059] As shown in Figure 6, the cable connection structure 1 of this embodiment is formed such that the widthwise dimensions of the pair of connecting conductors 32 of the connecting member 31 are different from each other.

[0060] In the cable connection structure 1 configured as described above, even when the widthwise sizes of the pair of connecting conductors 32 are different, deviations from a predetermined value of the characteristic impedance at the connection part 30 are suppressed when the extending size of the conductors 11, 21, and 32 at the connection part 30 is less than or equal to a predetermined size set based on the communication speed of data communication using the conductors 11, 21, and 32.

[0061] Thus, according to the cable connection structure of this embodiment, similar to the first embodiment, by making the size of the conductors 11, 21, and 32 in the extension direction of the connection portion 30 less than or equal to a predetermined size, it is possible to suppress deviation of the characteristic impedance at the connection portion 30 from a predetermined value, and to adjust the characteristic impedance to a predetermined value over the entire length of the communication conductor including the connection portion.

[0062] <Fifth Embodiment> Figure 7 shows a fifth embodiment of the present invention and is a schematic plan view of the connecting member. Components similar to those in the first embodiment are denoted by the same reference numerals.

[0063] In this embodiment, as shown in Figure 7, the cable connection structure 1 has a pair of connecting conductors 32 of the connecting member 31 that are bent and extend while being held by the insulating portion 33.

[0064] In the cable connection structure 1 configured as described above, even when the pair of connecting conductors 32 are bent and extending while being held by the insulating portion 33, deviations from a predetermined value of characteristic impedance at the connection portion 30 are suppressed when the size of the extending direction of the conductors 11, 21, and 32 at the connection portion 30 is less than or equal to a predetermined size set based on the communication speed of data communication using the conductors 11, 21, and 32.

[0065] Thus, according to the cable connection structure of this embodiment, similar to the first embodiment, by making the size of the conductors 11, 21, and 32 in the extension direction of the connection portion 30 less than or equal to a predetermined size, it is possible to suppress deviation of the characteristic impedance at the connection portion 30 from a predetermined value, and to adjust the characteristic impedance to a predetermined value over the entire length of the communication conductor including the connection portion.

[0066] Furthermore, it is preferable that the connecting conductor 32 extends in a bent state while being held by the insulating portion 33.

[0067] As a result, regardless of whether the connecting conductor 32 is bent or not, by keeping the size of the conductors 11, 21, and 32 in the extending direction at the connecting portion 30 below a predetermined size, it is possible to suppress deviations of the characteristic impedance at the connecting portion 30 from a predetermined value.

[0068] <Sixth Embodiment> Figure 8 shows a sixth embodiment of the present invention and is a schematic plan view of the connecting member. Components similar to those in the first embodiment are denoted by the same reference numerals.

[0069] In this embodiment, as shown in Figure 8, the cable connection structure 1 has a widthwise dimension of the pair of connecting conductors 32 of the connecting member 31, which changes in the middle portion in the extending direction.

[0070] In the cable connection structure 1 configured as described above, even when each of the pair of connecting conductors 32 is formed by connecting a separate member in the middle of its extending direction, deviations from a predetermined value of the characteristic impedance at the connection part 30 are suppressed when the size of the conductors 11, 21, and 32 in the extending direction at the connection part 30 is less than or equal to a predetermined size set based on the communication speed of data communication using the conductors 11, 21, and 32.

[0071] Thus, according to the cable connection structure of this embodiment, similar to the first embodiment, by making the size of the conductors 11, 21, and 32 in the extension direction of the connection portion 30 less than or equal to a predetermined size, it is possible to suppress deviation of the characteristic impedance at the connection portion 30 from a predetermined value, and to adjust the characteristic impedance to a predetermined value over the entire length of the communication conductor including the connection portion.

[0072] <Seventh Embodiment> Figure 9 shows a seventh embodiment of the present invention and is a schematic plan view of the connecting member. Components similar to those in the first embodiment are denoted by the same reference numerals.

[0073] As shown in Figure 9, the cable connection structure 1 of this embodiment has a branching structure 32a in which one of the connecting conductors 32 of the connecting member 31 branches in the middle portion in the extending direction. The branching structure 32a may be formed on one or both of the pair of connecting conductors 32.

[0074] In the cable connection structure 1 configured as described above, even when the connecting conductor 32 has a branching structure 32a, deviations from a predetermined value of the characteristic impedance at the connection part 30 are suppressed when the size of the conductors 11, 21, and 32 in the extending direction at the connection part 30 is less than or equal to a predetermined size set based on the communication speed of data communication using the conductors 11, 21, and 32.

[0075] Thus, according to the cable connection structure of this embodiment, similar to the first embodiment, by making the size of the conductors 11, 21, and 32 in the extension direction of the connection portion 30 less than or equal to a predetermined size, it is possible to suppress deviation of the characteristic impedance at the connection portion 30 from a predetermined value, and to adjust the characteristic impedance to a predetermined value over the entire length of the communication conductor including the connection portion.

[0076] <Eighth Embodiment> Figure 10 shows the eighth embodiment of the present invention and is a schematic side view of the cable connection structure. Components similar to those in the first embodiment are denoted by the same reference numerals.

[0077] As shown in Figure 10, the connecting member 31 of the cable connection structure 1 in this embodiment has a pair of connecting conductors 32 arranged on the upper surface of a sheet-like insulating portion 33. The pair of first communication conductors 11 and the pair of second communication conductors 21 are each joined to the connecting conductors 32 arranged on the upper surface side of the insulating portion 33 by soldering, brazing, or the like.

[0078] In the cable connection structure 1 configured as described above, even when the pair of connecting conductors 32 are connecting members 31 arranged on the upper surface of the sheet-like insulating portion 33, deviations from a predetermined value of characteristic impedance at the connection portion 30 are suppressed when the size of the conductors 11, 21, and 32 in the extending direction at the connection portion 30 is less than or equal to a predetermined size set based on the communication speed of data communication using the conductors 11, 21, and 32.

[0079] Thus, according to the cable connection structure of this embodiment, similar to the first embodiment, by making the size of the conductors 11, 21, and 32 in the extension direction of the connection portion 30 less than or equal to a predetermined size, it is possible to suppress deviation of the characteristic impedance at the connection portion 30 from a predetermined value, and to adjust the characteristic impedance to a predetermined value over the entire length of the communication conductor including the connection portion.

[0080] <Ninth Embodiment> Figure 11 shows the ninth embodiment of the present invention and is a schematic side view of the cable connection structure. Components similar to those in the first embodiment are denoted by the same reference numerals.

[0081] As shown in Figure 11, the connecting member 31 of the cable connection structure 1 in this embodiment has an insulating portion 33 formed in a rectangular parallelepiped shape. The pair of connecting conductors 32 each have the end on the first cable 10 side positioned on the lower side of the insulating portion 33, the end on the second cable 20 side positioned on the upper side of the insulating portion, and the middle portion extending in the vertical direction.

[0082] In the cable connection structure 1 configured as described above, even when the pair of connecting conductors 32 are connecting members 31 that extend vertically from a rectangular parallelepiped-shaped insulating portion 33, deviations from a predetermined value of characteristic impedance at the connection portion 30 are suppressed when the size of the conductors 11, 21, and 32 in the extending direction at the connection portion 30 is less than or equal to a predetermined size set based on the communication speed of data communication using the conductors 11, 21, and 32.

[0083] Thus, according to the cable connection structure of this embodiment, similar to the first embodiment, by making the size of the conductors 11, 21, and 32 in the extension direction of the connection portion 30 less than or equal to a predetermined size, it is possible to suppress deviation of the characteristic impedance at the connection portion 30 from a predetermined value, and to adjust the characteristic impedance to a predetermined value over the entire length of the communication conductor including the connection portion.

[0084] <Tenth Embodiment> Figure 12 shows a tenth embodiment of the present invention and is a schematic plan view of the cable connection structure. Components similar to those in the first embodiment are denoted by the same reference numerals.

[0085] As shown in Figure 12, the cable connection structure 1 of this embodiment has a first cable 10 that, in addition to a pair of first communication conductors 11, has a plurality of first multi-purpose conductors 12 for communication or power supply. The second cable 20 has a plurality of second multi-purpose conductors 22 for communication or power supply in addition to a pair of second communication conductors 21. Furthermore, the connecting member 31 has a pair of connecting conductors 32, as well as multi-purpose connecting conductors 32b that connect each of the plurality of first multi-purpose conductors 12 to the plurality of second multi-purpose conductors 22.

[0086] In the cable connection structure 1 configured as described above, even when the first cable 10 and the second cable 20 have a first multi-purpose conductor 12 and a second multi-purpose conductor 22 for communication or power supply, in addition to the first communication conductor 11 and the second communication conductor 21 which are subject to adjustment of characteristic impedance, deviations from a predetermined value of characteristic impedance at the connection part 30 are suppressed when the size of the conductors 11, 21, and 32 in the extending direction at the connection part 30 is less than or equal to a predetermined size set based on the communication speed of data communication using the conductors 11, 21, and 32.

[0087] Thus, according to the cable connection structure of this embodiment, similar to the first embodiment, by making the size of the conductors 11, 21, and 32 in the extension direction of the connection portion 30 less than or equal to a predetermined size, it is possible to suppress deviation of the characteristic impedance at the connection portion 30 from a predetermined value, and to adjust the characteristic impedance to a predetermined value over the entire length of the communication conductor including the connection portion.

[0088] <Eleventh Embodiment> Figures 13 to 15 show the eleventh embodiment of the present invention. Figure 13 is a schematic plan view of a cable connection structure with a shield formed thereon. Figure 14 is a cross-sectional view taken along line A-A in Figure 13. Figure 15 is a cross-sectional view taken along line B-B in Figure 13. Components similar to those in the first embodiment are denoted by the same reference numerals.

[0089] As shown in Figure 15, the first cable 10 of the cable connection structure 1 of this embodiment has a ground conductor 11a arranged on the widthwise outer side of a pair of first communication conductors 11 in the widthwise direction, and a shield 13 arranged across the entire upper surface. The ground conductor 11a and the shield 13 are electrically connected.

[0090] As shown in Figure 13, the second cable 20 has a shield 23 arranged on the outer circumference of a pair of second communication conductors 21.

[0091] As shown in Figures 13 to 15, the connecting member 31 has a ground conductor 32c arranged on the outside in the width direction of a pair of connecting conductors 32 in the width direction, and a shield 34 covering the bottom side. The ground conductor 32c and the shield 34 are electrically connected. The ground conductor 32c is connected to the ground.

[0092] As shown in Figure 13, the shield 23 of the second cable 20 is connected to the ground conductor 32c of the connecting member 31 via the drain wire 23a.

[0093] Here, the shields 13, 23, and 34 may be formed by creating thin films using methods such as plating, foiling, sputtering, or vapor deposition, or by braiding metal wires. Furthermore, the shields 13 and 34 are made of conductive materials such as copper or silver.

[0094] In the cable connection structure 1 configured as described above, the shield 13 of the first cable 10 and the shield 23 of the second cable 20 are connected via a ground conductor 32c located on the connecting member 31. As a result, the ground is shared by a single ground conductor 32c, thus suppressing structural complexity. In this case as well, the cable connection structure 1 suppresses deviation from a predetermined value of characteristic impedance at the connection part 30 when the size of the conductors 11, 21, and 32 in the extending direction at the connection part 30 is less than or equal to a predetermined size set based on the communication speed of data communication using the conductors 11, 21, and 32.

[0095] Thus, according to the cable connection structure of this embodiment, similar to the first embodiment, by making the size of the conductors 11, 21, and 32 in the extension direction of the connection portion 30 less than or equal to a predetermined size, it is possible to suppress deviation of the characteristic impedance at the connection portion 30 from a predetermined value, and to adjust the characteristic impedance to a predetermined value over the entire length of the communication conductor including the connection portion.

[0096] Furthermore, it is preferable that the connecting member 31 has a ground conductor 32c that is connected to the ground.

[0097] This makes it possible to more reliably suppress deviations from a predetermined value in the characteristic impedance of the connecting conductor 32 in the connecting member 31.

[0098] <Twelfth Embodiment> Figures 16 to 18 show a twelfth embodiment of the present invention. Figure 16 is a schematic plan view of a cable connection structure with a shield formed thereon. Figure 17 is a cross-sectional view taken along line A-A in Figure 16. Figure 18 is a cross-sectional view taken along line B-B in Figure 16. Components similar to those in the first embodiment are denoted by the same reference numerals.

[0099] As shown in Figure 18, the first cable 10 of the cable connection structure 1 of this embodiment has a pair of ground conductors 11a arranged on both outer sides in the width direction of a pair of first communication conductors 11 in the width direction, and a shield 13 arranged across the entire upper surface. The pair of ground conductors 11a and the shield 13 are electrically connected.

[0100] As shown in Figure 16, the second cable 20 has a shield 23 arranged on the outer circumference of a pair of second communication conductors 21.

[0101] As shown in Figures 13 to 15, the connecting member 31 has a pair of ground conductors 32c arranged on both outer sides in the width direction of a pair of connecting conductors 32 in the width direction, and a shield 34 covering the lower side. The ground conductors 32c and the shield 34 are electrically connected.

[0102] As shown in Figure 16, the shield 23 of the second cable 20 is connected to the ground conductor 32c of the connecting member 31 via the drain wire 23a.

[0103] In the cable connection structure 1 configured as described above, the shield 13 of the first cable 10 and the shield 23 of the second cable 20 are connected via a pair of ground conductors 32c arranged on the connecting member 31. As a result, the pair of ground conductors 32c are arranged on both outer sides in the width direction of the pair of connecting conductors 32, thereby improving resistance to noise. Furthermore, since ground conductors are arranged on both outer sides in the width direction of the pair of connecting conductors 32 and the pair of first communication conductors 11, physical symmetry is created, and communication performance can be stabilized. In this case as well, the cable connection structure 1 suppresses deviations from a predetermined value of characteristic impedance at the connection part 30 when the size in the extending direction of the conductors 11, 21, and 32 at the connection part 30 is less than or equal to a predetermined size set based on the communication speed of data communication using the conductors 11, 21, and 32.

[0104] Thus, according to the cable connection structure of this embodiment, similar to the first embodiment, by making the size of the conductors 11, 21, and 32 in the extension direction of the connection portion 30 less than or equal to a predetermined size, it is possible to suppress deviation of the characteristic impedance at the connection portion 30 from a predetermined value, and to adjust the characteristic impedance to a predetermined value over the entire length of the communication conductor including the connection portion.

[0105] <Third Embodiment> Figures 19 and 20 show a thirteenth embodiment of the present invention. Figure 19 is a schematic cross-sectional view of the second cable side of the connecting member 31. Figure 20 is a schematic cross-sectional view of the first cable side of the connecting member 31. Components similar to those in the first embodiment are denoted by the same reference numerals.

[0106] In this embodiment, as shown in Figures 19 and 20, the cable connection structure 1 has a pair of connecting conductors 32 arranged in the width direction on the upper side of the insulating portion 33 of the connecting member 31, and a ground conductor 32c is arranged across the entire lower surface of the insulating portion 33. Furthermore, the ground conductor 11a arranged on the lower side of the insulating portion 33 is covered by a shield 34.

[0107] In the cable connection structure 1 configured as described above, deviations from a predetermined value of characteristic impedance at the connection part 30 are suppressed when the size of the conductors 11, 21, and 32 in the extending direction at the connection part 30 is less than or equal to a predetermined size set based on the communication speed of data communication using the conductors 11, 21, and 32.

[0108] Thus, according to the cable connection structure of this embodiment, similar to the first embodiment, by making the size of the conductors 11, 21, and 32 in the extension direction of the connection portion 30 less than or equal to a predetermined size, it is possible to suppress deviation of the characteristic impedance at the connection portion 30 from a predetermined value, and to adjust the characteristic impedance to a predetermined value over the entire length of the communication conductor including the connection portion.

[0109] In the above embodiment, a cable connection structure 1 is shown that connects a first cable 10, which is a flat cable, and a second cable 20, which is a twisted pair cable, but the invention is not limited to this. Any cable connection structure that connects cables of different types, each containing at least one pair of communication conductors, is acceptable. For example, the first cable or the second cable may be a coaxial cable in which one conductor is arranged on the outer circumference of the other conductor, or it may be a parallel two-wire cable in which a pair of linear conductors extend parallel to each other. Furthermore, this cable connection structure can be applied to connecting a flat cable to a coaxial cable, or a twisted pair cable to a coaxial cable.

[0110] Furthermore, although the above embodiment shows a cable connection structure in which a pair of second communication conductors 21 having the same cross-sectional shape are connected to a pair of first communication conductors 11 having the same cross-sectional shape, the cable connection structure is not limited to this. As a cable connection structure, a pair of first communication conductors having different cross-sectional shapes may be connected to second communication conductors having the same or different cross-sectional shapes.

[0111] Furthermore, in the above embodiment, a cable connection structure 1 is shown in which each of the pair of first communication conductors 11 of the first cable 10, which is a flat cable, is connected to each of the pair of second communication conductors 21 of the second cable 20, which is a twisted pair cable, but the invention is not limited to this.

[0112] As an example of the cable connection structure 1, as shown in Figure 21, each of the pair of second communication conductors 21 of the second cable 20, which is a twisted pair cable, may be connected to one end of each of the pair of first communication conductors 11 of the first cable 10, which is a flat cable, and each of the pair of third communication cables 41 of the third cable 40, which is a twisted pair cable, may be connected to the other end of each of the pair of first communication conductors 11.

[0113] Furthermore, as the cable connection structure 1, for example, as shown in Figure 22, each of the pair of second communication conductors 21 of the second cable 20, which is a twisted pair cable, may be connected to each of the pair of first communication conductors 11 of the first cable 10, which is a flat cable, and each of the pair of third communication cables 51 of the third cable 50, which is a flat cable, may be connected to each of the other ends of the pair of first communication conductors 11.

[0114] Furthermore, as the cable connection structure 1, for example, as shown in Figure 23, one end of each of the pair of second communication conductors 21 of the second cable 20, which is a twisted pair cable, may be connected to each of the pair of first communication conductors 11 of the first cable 10, which is a flat cable, and the other end of each of the pair of second communication cables 11 may be connected to the pair of third communication conductors 61 of the third cable 60, which is a flat cable.

[0115] The cable connection structure 1 may be arranged at multiple locations on the communication circuit, as shown in Figures 21 to 23. Furthermore, the types of cables connected via the cable connection structure 1 may be in any combination. Also, one cable connected via the cable connection structure 1 may be shielded, while the other is unshielded. The length of each cable connected via the cable connection structure 1 should be at least equal to the length in the extending direction of the conductor of the connection portion 30.

[0116] <Fourteenth Embodiment> Figure 24 shows the fourteenth embodiment of the present invention. Figure 24 is a graph showing the results of a test to determine whether the characteristic impedance can be maintained within a predetermined range in relation to the size of the conductor in the extending direction and the communication speed.

[0117] In this embodiment, Figure 24 illustrates the results of a test to determine whether the characteristic impedance can be maintained within a predetermined range in relation to the magnitude of the conductor extension direction in multiple types of connection parts and multiple types of communication speeds.

[0118] In the test to determine whether the characteristic impedance can be maintained within a predetermined range, the characteristic impedance was measured for each connection point with a conductor extension length of 4 mm, 5 mm, 18 mm, 36 mm, and 80 mm, and for each communication speed of 10 Mbps, 100 Mbps, 1000 Mbps, 2500 Mbps, 5000 Mbps, and 10000 Mbps. It was then determined whether the measured characteristic impedance could be maintained within the range of 100 Ω ± 10 Ω.

[0119] When the length of the conductor in the extension direction at the connection point is 4 mm, it can be seen that the characteristic impedance can be maintained within a predetermined range at communication speeds of 10 Mbps, 100 Mbps, 1000 Mbps, 2500 Mbps, 5000 Mbps, and 10000 Mbps.

[0120] Furthermore, when the length of the conductor in the extension direction at the connection point is 5 mm, it can be seen that the characteristic impedance can be maintained within a predetermined range at communication speeds of 10 Mbps, 100 Mbps, and 1000 Mbps, but that the characteristic impedance cannot be maintained within a predetermined range at communication speeds of 2500 Mbps, 5000 Mbps, and 10000 Mbps.

[0121] Furthermore, when the length of the conductor in the extension direction at the connection point is 18 mm, it can be seen that the characteristic impedance can be maintained within a predetermined range at communication speeds of 10 Mbps and 100 Mbps, but that the characteristic impedance cannot be maintained within a predetermined range at communication speeds of 1000 Mbps, 2500 Mbps, 5000 Mbps, and 10000 Mbps.

[0122] Furthermore, when the length of the conductor in the extension direction at the connection point is 36 mm, it can be seen that the characteristic impedance can be maintained within a predetermined range at communication speeds of 10 Mbps and 100 Mbps, but that the characteristic impedance cannot be maintained within a predetermined range at communication speeds of 1000 Mbps, 2500 Mbps, 5000 Mbps, and 10000 Mbps.

[0123] Furthermore, it can be seen that when the length of the conductor in the extension direction at the connection point is 80 mm, the characteristic impedance cannot be maintained within the predetermined range even at communication speeds of 10 Mbps and 100 Mbps.

[0124] In other words, it is clear that the size of the conductor in the direction of extension at the connection point needs to be reduced as the communication speed increases.

[0125] Thus, according to the cable connection structure of this embodiment, similar to the first embodiment, by making the size of the conductor in the extending direction at the connection portion less than or equal to a predetermined size, it is possible to suppress deviations of the characteristic impedance at the connection portion from a predetermined value, and to adjust the characteristic impedance to a predetermined value over the entire length of the communication conductor including the connection portion.

[0126] Furthermore, the size of the conductor in the extending direction at the connection point is preferably 36 mm or less when the communication speed is 100 Mbps or less, 5 mm or less when the communication speed is greater than 100 Mbps and 1000 Mbps or less, and 4 mm or less when the communication speed is greater than 1000 Mbps.

[0127] This allows the characteristic impedance to be adjusted to a predetermined value throughout the entire conductor used for data communication, including the connection, by setting the size of the conductor at the connection point based on the data communication speed using the conductor.

[0128] 1 Cable connection structure 10 First cable 10a First processing section 11 First communication conductor 20 Second cable 20a Second processing section 21 Second communication conductor 30 Connection section 31 Connection member 32 Connection conductor 32c Ground conductor 33 Insulation section

Claims

1. A cable connection structure for connecting a first cable including at least one pair of first communication conductors and a second cable including at least one pair of second communication conductors, wherein the first communication conductors are electrically connected to the second communication conductors, the first cable and the second cable are each different types of cables, a first processing portion is formed on the end of the first cable that is connected to the second cable, a second processing portion is formed on the end of the second cable that is connected to the first cable, a connection portion is arranged between the base end of the first processing portion of the first cable and the base end of the second processing portion of the second cable when the first cable and the second cable are connected, and the size of the first communication conductor and the second communication conductor in the extending direction at the connection portion is less than or equal to a predetermined size set based on the communication speed of data communication using the first communication conductor and the second communication conductor.

2. The cable connection structure according to claim 1, wherein the first cable or the second cable is a flat cable in which a plurality of conductors are arranged at intervals from one another.

3. The cable connection structure according to claim 1, wherein the first cable or the second cable is a twisted cable in which a plurality of conductors are twisted together.

4. The cable connection structure according to claim 1, wherein the first cable or the second cable is a coaxial cable in which one conductor is arranged on the outer circumference of the other conductor.

5. The cable connection structure according to claim 1, comprising a connecting member for connecting the first communication conductor and the second communication conductor, wherein the connecting member comprises a pair of connecting conductors for electrically connecting each of the pair of first communication conductors to each of the pair of second communication conductors, and an insulating portion for holding the pair of connecting conductors.

6. The cable connection structure according to claim 5, wherein the connecting conductor extends in a bent state while being held by the insulating portion.

7. The cable connection structure according to claim 5, wherein the connecting member has a ground conductor connected to the ground.

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