JP2017195095A - Multicore cable with protective tube and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multicore cable that changes cross-sectional positions of a plurality of insulation conductors and a plurality of non-insulation conductors over a longer direction and has a low possibility of degradation of transmission performance.SOLUTION: A multicore cable 1 has n conductor bundles 10 to 40, the n conductor bundles 10 to 40 each have at least one insulation conductor 11 to 13 and at least one non-insulation conductor 14, frequency of appearance of the same plane on a cross section vertical to a longer direction is AF(N) per unit length, where N=1 to n, at least one of AF(N), where N=1 to n, is difference from others, a ratio of the number of the insulation conductors and the number of the non-insulation conductors in each of the n conductive bundle is in a range of 2:3 to 4:1, the non-insulation conductor becoming a pair with the insulation conductor is not fixed and each insulation conductor becomes a pair with the non-insulation conductor of the same conductor bundle and/or the non-insulation conductor of a different conductor bundle.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a multi-core cable with a protective tube and a method for manufacturing the same.

  In order to reduce the diameter of a multi-core cable such as an ultrasonic probe cable and reduce the manufacturing cost, it is known that a coaxial cable is not used for a signal line for transmitting a signal. Patent Document 1 describes a multi-core cable having five insulated conductors and one non-insulated conductor. In the multi-core cable described in Patent Document 1, five insulated conductors and one non-insulated conductor are arranged in a row on the outer periphery of the tension member and wound helically. The multi-core cable described in Patent Document 1 can have good flexibility because the insulated conductors and the non-insulated conductors are arranged in a row and wound helically. Moreover, since the multi-core cable described in Patent Document 1 does not include a coaxial cable, the diameter can be reduced and the manufacturing cost can be reduced.

However, in the multi-core cable described in Patent Document 1, when the insulated conductors are adjacent without interposing the non-insulated conductor, two of the five are adjacent to the non-insulated conductor, but three are non-insulated conductors. Insulating conductors are adjacent to each other without being adjacent to each other, and these adjacent insulating conductors are arranged in parallel over the longitudinal direction of the insulating conductor as signal lines so that the capacitive coupling between the signal lines does not change continuously. Therefore, crosstalk increases. In this way, they are arranged in parallel at the same interval, so that crosstalk increases and signal strength and signal quality may deteriorate.
Further, in the cable described in Patent Document 1, a thin tape-like wound body layer (coating) is integrally wound around the multi-core cable in a spiral manner, so that an impact from the radial direction of the cable is prevented. Direct transmission to the multi-core cable may cause damage to the multi-core cable. This is because when an ultrasonic probe cable is used indoors in a medical facility, it is wired to a fixing device, so it is difficult to assume the impact from the radial direction of the cable in terms of arrangement, but the cable is not suitable for outdoor use. In the situation where the cable is carried, the arrangement of the cable is not determined, and in the situation where the cable is wired along the ground surface, it may be stepped on, and durability against impact is required.

Japanese Patent Laid-Open No. 11-162268

  As described above, when only the insulated conductors are arranged adjacent to each other, the crosstalk increases, and there is a possibility that the signal strength and the signal quality are deteriorated. In addition, even when the positions of the insulated conductor and the non-insulated conductor are changed at random along the longitudinal direction, the distance between the insulated conductor and the non-insulated conductor varies greatly. The characteristic impedance is not matched, and noise and reflected waves increase, which may reduce the transmission performance of the multi-core cable.

  Therefore, the present invention provides a cross section of a plurality of insulated conductors and a plurality of non-insulated conductors in which the non-insulated conductor is always disposed near the insulated conductor, and the insulated conductors and the insulated conductors and An object of the present invention is to provide a multi-core cable with a protective tube that is less likely to deteriorate transmission performance by randomly changing the positional relationship of non-insulated conductors and that has improved durability against impact from the radial direction of the cable. And

  A multi-core cable with a protective tube according to the present invention includes a multi-core cable and a metal protective tube that can be bent in a state in which the multi-core cable is inserted, and the multi-core cable includes n conductors. Each of the n conductor bundles has at least one insulated conductor and at least one non-insulated conductor, and the frequency of occurrence of the same surface in a cross section perpendicular to the longitudinal direction is as follows: AF (N) per unit length (N = 1 to n), and at least one of the AF (N) (N = 1 to n) is different from the others, and the insulating conductors in each of the n conductor bundles The ratio of the number of non-insulated conductors to the number of non-insulated conductors is in the range of 2: 3 to 4: 1, the pair of insulated conductors and non-insulated conductors is not fixed, and each insulated conductor is non-insulated of the same conductor bundle Paired with non-insulated conductors of conductors and / or different conductor bundles.

The multi-core cable of the multi-core cable with a protective tube according to the present invention is different from the other in at least one of the frequencies AF (N) (N = 1 to n) in which the same surface appears in the cross section perpendicular to the longitudinal direction of the conductor bundle. Therefore, it is possible to reduce crosstalk by varying the capacitive coupling between the insulated conductors in the longitudinal direction. Moreover, the multi-core cable according to the present invention has a ratio of the number of insulated conductors to the number of non-insulated conductors in each conductor bundle in the range of 2: 3 to 4: 1, so that the insulated conductors are non-insulated conductors. Arranged nearby, the variation in capacitance of the insulated conductor can be reduced.
Unlike the twisted pair, in the multi-core cable according to the present invention, the non-insulated conductor paired with the insulated conductor is not fixed. That is, an insulated conductor and a non-insulated conductor in the same bundle may be paired, or an insulated conductor and a non-insulated conductor in another adjacent conductor bundle may be paired. For this reason, the state becomes more random than the apparent structure, and the crosstalk reduction effect is improved. Furthermore, even in the configuration of many insulated conductors and fewer non-insulated conductors, there must be non-insulated conductors near the insulated conductors in the entire cable, not just in the conductor bundle. Thus, the effect of reducing the variation in capacitance is further improved.
Furthermore, the multi-core cable with a protective tube according to the present invention includes a metal protective tube that can be bent in a state in which the multi-core cable is inserted, so that durability against an impact from the radial direction of the cable is improved. In addition, the use range of the ultrasonic probe cable can be widely and safely used in indoor / outdoor or fixed / moving situations, and versatility can be improved.

  In the multi-core cable with a protective tube according to the present invention, the ratio of the number of insulated conductors to the number of non-insulated conductors in each of the n conductor bundles is preferably in the range of 1: 1 to 4: 1. .

Furthermore, in the multi-core cable with a protective tube according to the present invention, the ratio of the number of insulated conductors and the number of non-insulated conductors in each of the n conductor bundles is in a range of 2: 3 or more and less than 1: 1. The ratio of the average value of the diameters of the insulated conductors and the average value of the diameters of the non-insulated conductors of the n conductor bundles is preferably in the range of 1.2: 1 or more and 4: 1 or less.

  In the multi-core cable with a protective tube according to the present invention, the shortest distance from the center of each insulated conductor of the n conductor bundles to the surface of the adjacent non-insulated conductor is insulated in a cross section perpendicular to the longitudinal direction of the conductor bundle. The average value of the values divided by the distance from the center of the conductor to the outermost surface of the insulated conductor is preferably in the range of 1 to 1.3.

  The multi-core cable with a protective tube according to the present invention is an average value obtained by dividing the shortest distance from the center of each insulated conductor to the surface of the adjacent non-insulated conductor by the distance from the center of the insulated conductor to the outermost surface of the insulated conductor. Is in the range of 1 to 1.3, it is possible to prevent a decrease in transmission performance due to an increase in noise and reflected waves due to characteristic impedance mismatch.

  In the multi-core cable with a protective tube according to the present invention, the frequency of occurrence of the same surface in the cross section perpendicular to the longitudinal direction of the entire conductor bundle is 0.01 times / m or less in the entire n conductor bundle. Preferably there is.

  In the multi-core cable with a protective tube according to the present invention, the frequency of appearance of the same surface in a cross section perpendicular to the longitudinal direction of the entire conductor bundle is 0.01 times / m or less in the entire n conductor bundles, It is possible to reduce the far-end crosstalk by changing the capacitive coupling between the insulated conductors in the longitudinal direction of the entire conductor bundle without having the same cross-sectional shape over 100 m or more.

  Furthermore, in the multi-core cable with a protective tube according to the present invention, the combined resistance when the insulated conductors of the n conductor bundles are connected in parallel is the combined resistance when the non-insulated conductors of the n conductor bundles are connected in parallel. It is preferable that it is larger than the resistance.

  In the multi-core cable with a protective tube according to the present invention, the non-insulated conductor is used as a signal line by making the combined resistance when the insulated conductors are connected in parallel to be larger than the combined resistance when the non-insulated conductors are connected in parallel. It functions and can prevent noise from increasing.

Furthermore, the multi-core cable with a protective tube according to the present invention includes a multi-core cable,
A metal protective tube that can be bent in a state where the multi-core cable is inserted,
The multi-core cable has n conductor bundles, and each of the n conductor bundles has at least one insulated conductor and at least one non-insulated conductor, and the at least one conductor bundle. The insulated conductor and the at least one non-insulated conductor are twisted T (N) (N = 1 to n) times per unit length, and the n conductor bundles are twisted T1 times per unit length. , At least one of the T (N) (N = 1 to n) is different from the others, and the ratio of the number of the insulated conductors to the number of the non-insulated conductors in each of the n conductor bundles is 2: A range of 3-4: 1, where the pairs of insulated conductors and non-insulated conductors are not fixed and each insulated conductor is paired with a non-insulated conductor of the same conductor bundle and / or a non-insulated conductor of a different conductor bundle. It is characterized by.

In the multi-core cable according to the present invention, since the insulated conductor and the non-insulator are different from those of other conductor bundles in at least one of the number of twists per unit length, the capacitive coupling between the insulated conductors is varied in the longitudinal direction. Far-end crosstalk can be reduced. Further, the multi-core cable according to the present invention has a capacitance ratio of the insulated conductors by setting the ratio of the number of insulated conductors to the number of non-insulated conductors in each conductor bundle in the range of 2: 3 to 4: 1. Variations can be reduced.
Furthermore, the multi-core cable with a protective tube according to the present invention includes a metal protective tube that can be bent in a state in which the multi-core cable is inserted, so that durability against an impact from the radial direction of the cable is improved. In addition, the use range of the ultrasonic probe cable can be widely and safely used in indoor / outdoor or fixed / moving situations, and versatility can be improved.

  Further, in the method of manufacturing a multi-core cable with a protective tube, n conductor bundles each having at least one insulated conductor and at least one non-insulated conductor are used as the at least one insulated conductor and the at least one insulated conductor. The non-insulated conductors are twisted T (N) (N = 1 to n) per unit length in the longitudinal direction of the conductor bundle, and the length of the conductor group is a conductor group in which the n conductor bundles are twisted. Twist per unit length in the direction, at least one of the T (N) (N = 1 to n) is different from the others, the number of the insulated conductors in each of the n conductor bundles and the non-insulated The ratio of the number of conductors is in the range of 2: 3-4: 1, the pairs of insulated conductors and non-insulated conductors are not fixed, and each insulated conductor is a non-insulated conductor of the same conductor bundle and / or different A pair of non-insulated conductors in a conductor bundle A multi-core cable manufacturing process for manufacturing a multi-core cable, and a protective pipe insertion process for inserting the multi-core cable manufactured by the multi-core cable manufacturing process into a bendable metal protective pipe. And

The method for producing a multi-core cable with a protective tube according to the present invention comprises twisting an insulated conductor and a non-insulator as many times as twisted per unit length in the longitudinal direction of the conductor bundle, preparing n such conductor bundles, Since at least one twist per unit length is different from the others, the capacitive coupling between the insulated conductors can be varied in the longitudinal direction to reduce far-end crosstalk. Further, the multi-core cable according to the present invention has a capacitance ratio of the insulated conductors by setting the ratio of the number of insulated conductors to the number of non-insulated conductors in each conductor bundle in the range of 2: 3 to 4: 1. Variations can be reduced.
In addition, it is equipped with a metal protective tube that can be bent while a multi-core cable is inserted, and the durability against impacts from the radial direction of the cable is improved. Can be used widely and safely in indoor / outdoor or fixed / moving situations, and versatility can be improved.

  According to the present invention, the positions of the plurality of insulated conductors and the plurality of non-insulated conductors in the cross-section are randomly changed over the longitudinal direction, the transmission performance is unlikely to deteriorate, and the cable is resistant to impact from the radial direction. It is possible to provide a multi-core cable with a protective tube with improved performance.

It is a disassembled perspective view of the multi-core cable which concerns on embodiment. It is a figure which illustrates the cross section perpendicular | vertical to the longitudinal direction of the conductor group of the multicore cable whose ratio of the number of an insulated conductor and a non-insulated conductor is 1: 1-4: 1, (a) is an insulated conductor and a non-insulated conductor. (B) is an example when the ratio of the number of insulated conductors and non-insulated conductors is 2: 1, and (c) is an example of insulated conductors and non-insulated conductors. This is an example when the ratio of the numbers is 4: 1, and (d) is an example when the ratio of the number of insulated conductors and non-insulated conductors is 2: 3. It is a side view before each of the 1st conductor bundle shown in Drawing 1, the 2nd conductor bundle, the 3rd conductor bundle, and the 4th conductor bundle twisted with other conductor bundles, (a) is the side of the 1st conductor bundle (B) is a side view of the second conductor bundle, (c) is a side view of the third conductor bundle, and (d) is a side view of the fourth conductor bundle. It is a figure which shows the phase relationship of the cross section perpendicular | vertical to the longitudinal direction before and after each of the 1st conductor bundle-4th conductor bundle shown in FIG. 1 is twisted collectively. It is a flowchart which shows the manufacturing process of the multi-core cable which concerns on embodiment. It is a figure which shows the twist machine used when twisting each of a conductor bundle and twisting together a conductor bundle. It is a figure which shows the operation state of the twister shown in FIG. It is a flowchart which shows the process which determines the "frequency that the same surface appears in a cross section perpendicular | vertical to a longitudinal direction". It is a 1st figure explaining the process which determines "the frequency that the same surface appears in a cross section perpendicular | vertical to a longitudinal direction". (A) is a 2nd figure explaining the process which determines "the frequency which the same surface appears in a cross section perpendicular | vertical to a longitudinal direction", (b) is the 2nd figure explaining the process which "the same surface appears in a cross section perpendicular | vertical to a longitudinal direction It is the 3rd figure explaining the process which determines "frequency". The crosstalk frequency characteristics of the eight cables of the comparative example, the first example, the second example, the third example, the fourth example, the fifth example, the sixth example, and the seventh example are shown. FIG. It is a figure which shows the change of crosstalk when the ratio of the number of the insulated conductors contained in a cable and the number of non-insulated conductors is changed when the frequency of a signal is 20 [MHz]. (A) is a 2nd figure explaining the process which determines "the frequency which the same surface appears in a cross section perpendicular | vertical to a longitudinal direction", (b) is the 2nd figure explaining the process which "the same surface appears in a cross section perpendicular | vertical to a longitudinal direction It is the 3rd figure explaining the process which determines "frequency".

  A multi-core cable with a protective tube and a method for manufacturing the same according to the present invention will be described below with reference to the drawings. However, it should be noted that the technical scope of the present invention is not limited to these embodiments, and extends to equivalents to the invention described in the claims.

(Outline of the multi-core cable according to the present invention)
The multi-core cable with a protective tube according to the present invention includes n conductor bundles in which the ratio of the number of insulated conductors to the number of non-insulated conductors is in the range of 2: 3 to 4: 1. Here, at least one of the n conductor bundles is different from the other (n-1) conductor bundles in that the cross-sectional shape perpendicular to the longitudinal direction of the conductor bundle is the same. By adopting such a configuration, a non-insulated conductor is always adjacent to the insulated conductor as a conductor bundle constituting the cable. In addition, since at least one of the n conductor bundles has a different frequency from the other (n-1) conductor bundles, the frequency of the cross section perpendicular to the longitudinal direction of the entire n conductor bundles is the same. The frequency with which the cross-sectional shape of these conductor bundles is the same is lower than the frequency of the same cross-section, and the frequency with which the same cross-section appears up to a predetermined length in the longitudinal direction of the cable is lower. Thus, in the multi-core cable according to the present invention, the positions in the cross-sections of the plurality of insulated conductors and the plurality of non-insulated conductors can be changed randomly along the longitudinal direction, and the possibility that the transmission performance is lowered can be reduced. .
Moreover, in the multicore cable with a protective tube according to the present invention, the non-insulated conductor paired with the insulated conductor is not fixed. That is, an insulated conductor and a non-insulated conductor in the same bundle may be paired, or an insulated conductor and a non-insulated conductor in another adjacent conductor bundle may be paired. For this reason, the state becomes more random than the apparent structure, and the crosstalk reduction effect is improved. Furthermore, even in the configuration of many insulated conductors and fewer non-insulated conductors, there must be non-insulated conductors near the insulated conductors in the entire cable, not just in the conductor bundle. Thus, the effect of reducing the variation in capacitance is further improved.
In addition, the multi-core cable with a protective tube according to the present invention includes a metal protective tube that protects the multi-core cable and improves durability against an impact from the radial direction of the cable. Can be used widely and safely in indoor / outdoor or fixed / moving situations, and versatility can be improved.

(Configuration of multi-core cable according to the embodiment)
FIG. 1 is an exploded perspective view of a multi-core cable according to an embodiment.

  The multicore cable 1 with a protective tube includes a first conductor bundle 10, a second conductor bundle 20, a third conductor bundle 30, a fourth conductor bundle 40, a protective tube 50, and a sheath 60. The first conductor bundle 10 includes an eleventh insulated conductor 11, a twelfth insulated conductor 12, a thirteenth insulated conductor 13, and a first non-insulated conductor 14. The second conductor bundle 20 includes a twenty-first insulating conductor 21, a twenty-second insulating conductor 22, a twenty-third insulating conductor 23, and a second non-insulating conductor 24. The third conductor bundle 30 includes a 31st insulated conductor 31, a 32nd insulated conductor 32, a 33rd insulated conductor 33, and a third non-insulated conductor 34. The fourth conductor bundle 40 includes a 41st insulated conductor 41, a 42nd insulated conductor 42, a 43rd insulated conductor 43, and a fourth non-insulated conductor 44. In the multi-core cable 1, each of the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30, and the fourth conductor bundle 40 includes three insulated conductors and one non-insulated conductor. However, in the multi-core cable according to the present invention, the ratio of the number of insulated conductors and non-insulated conductors may be in the range of 2: 3 to 4: 1. In the multi-core cable according to the present invention, the average value of values obtained by dividing the shortest distance from the center of each insulated conductor to the surface of the adjacent non-insulated conductor by the distance from the center of the insulated conductor to the outermost surface of the insulated conductor is The total number of insulated conductors and non-insulated conductors included in each conductor bundle is preferably 10 or less so as to be in the range of 1 to 1.3. In the conductor bundle, one insulated conductor and one non-insulated conductor have a small number of signal lines, but the overall cable diameter becomes too large. Therefore, the total number of insulated conductors and non-insulated conductors included in each conductor bundle is three. The above is preferable.

  FIG. 2 is a diagram illustrating a cross section perpendicular to the longitudinal direction of the conductors of a multi-core cable in which the ratio of the number of insulated conductors and non-insulated conductors is 2: 3 to 4: 1. FIG. 2A is an example when the ratio of the number of insulated conductors and non-insulated conductors is 1: 1, and FIG. 2B is the example when the ratio of the number of insulated conductors and non-insulated conductors is 2: 1. FIG. 2C is an example when the ratio of the number of insulated conductors and non-insulated conductors is 4: 1, and FIG. 2D is the example where the ratio of the number of insulated conductors and non-insulated conductors is 2: 3 is an example. 2 (a) to 2 (d), the broken line conceptually shows the region of the conductor bundle.

  A cable conductor (hereinafter referred to as “core”) 200 having a 1: 1 ratio of insulated conductors and non-insulated conductors includes a first conductor bundle 210 to a fourth conductor bundle 240. Each of the insulated conductor 211 of the first conductor bundle 210 to the insulated conductor 241 of the fourth conductor bundle 240 is close to any of the non-insulated conductor 212 of the first conductor bundle 210 to the non-insulated conductor 242 of the fourth conductor bundle 240. Be placed.

  The core 300 in which the ratio of the number of insulated conductors and non-insulated conductors is 2: 1 includes a first conductor bundle 310 to a fourth conductor bundle 340. Each of the insulated conductors 311 and 312 of the first conductor bundle 310 to the insulated conductors 341 and 342 of the fourth conductor bundle 340 is any of the non-insulated conductor 313 of the first conductor bundle 310 to the non-insulated conductor 343 of the fourth conductor bundle 340. It is arranged close to the heel.

  The core 500 in which the ratio of the number of insulated conductors and non-insulated conductors is 4: 1 includes a first conductor bundle 510 to a fourth conductor bundle 540. The insulated conductors 511 to 514, 521 to 524, 531 to 534, and 541 to 544 of the conductor part 500 are the non-insulated conductors 545 of the first conductor bundle 510 to the non-insulated conductors 545 of the first conductor bundle 510 except for the insulated conductor 542. It arrange | positions in close proximity to either. The insulated conductor 542 is far from the non-insulated conductor 545 of the same fourth conductor bundle 540, but is close to the non-insulated conductor 535 of the third conductor bundle 530 that is a different conductor bundle. And in the conductor part 500, the average value of the distance between each insulated conductor and a non-insulated conductor is 1.3 times or less of the aperture of a non-insulated conductor. Here, the term “average value of the distance between each of the insulated conductors and the non-insulated conductor” means that a plurality of cross sections perpendicular to the longitudinal direction of the multi-core cable 1 are sampled, and the insulated conductors in each cross section are not Measured at multiple locations in the relationship with insulated conductors, the value obtained by dividing the shortest distance from the center of each insulated conductor of the conductor bundle to the surface of the adjacent non-insulated conductor by the distance from the center of the insulated conductor to the outermost surface of the insulated conductor The average value of the measured values (hereinafter the same). In one example, the number of cross-sections to be sampled is 5, and “the shortest distance from the center of each insulated conductor of the conductor bundle to the surface of the adjacent non-insulated conductor is measured in one cross-section from the center of the insulated conductor to the insulated conductor. The number of “values divided by the distance to the outermost surface” is 12 (the cross section is radially divided into 12 equal parts, and each of the above-mentioned values in each equally divided space is 1 each).

  The core 600 in which the ratio of the number of insulated conductors and non-insulated conductors is 2: 3 includes a first conductor bundle 610 to a fourth conductor bundle 640. The insulated conductors 612, 613, 621, 623, 632, 633, 642 and 644 of the core 600 are any of the non-insulated conductors 611, 614, 615, 622, 624, 625, 631, 634, 635, 641, 643 and 645. It is arranged close to the heel. In the core 600, the average value of the distance between each of the insulated conductors and the non-insulated conductor is 1.3 times or less the diameter of the non-insulated conductor.

  In FIG. 1, the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30, and the fourth conductor bundle 40 are respectively T (1), T (2), T per unit length in the longitudinal direction of the conductor bundle. Twisted in the left direction by (3) and T (4) times. In one example, the twist pitch L1 at which the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30, and the fourth conductor bundle 40 are twisted together is 60 mm. The twist pitches of the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30, and the fourth conductor bundle 40 at this time are 4 mm, 6 mm, 7 mm, and 9 mm, respectively, for example.

  The insulated conductors of the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30, and the fourth conductor bundle 40 are each made of a core material made of a copper alloy containing silver plating tin and polytetrafluoroethylene (PFA). And a covering layer formed around the core material. The insulated conductors of the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30, and the fourth conductor bundle 40 function as signal lines for transmitting signals. The insulated conductor diameters of the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30, and the fourth conductor bundle 40 are equal to each other. The diameters of the cores of the insulated conductors of the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30, and the fourth conductor bundle 40 are equal to each other.

  The non-insulated conductors of the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30, and the fourth conductor bundle 40 are formed of a copper alloy containing silver-plated tin, like the core material of the insulated conductor. The non-insulated conductors of the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30, and the fourth conductor bundle 40 are each grounded and function as drain lines. The diameters of the non-insulated conductors of the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30, and the fourth conductor bundle 40 are equal to each other, and the first conductor bundle 10, the second conductor bundle 20, and the third conductor bundle 30 are the same. And the diameter of the core of the insulated conductor of the fourth conductor bundle 40 is larger.

  FIG. 3 is a side view before each of the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30, and the fourth conductor bundle 40 is twisted with another conductor bundle. 3A is a side view of the first conductor bundle 10, FIG. 3B is a side view of the second conductor bundle 20, and FIG. 3C is a side view of the third conductor bundle 30. FIG. 3D is a side view of the fourth conductor bundle 40.

  The first conductor bundle 10 is wound in the order of the eleventh insulated conductor 11, the twelfth insulated conductor 12, the thirteenth insulated conductor 13, and the first non-insulated conductor 14 in the order of T (1) turns per unit length in the longitudinal direction of the conductor bundle. It is formed by being twisted. The second conductor bundle 20 is T (2) times per unit length in the longitudinal direction of the conductor bundle in the order of the 21st insulated conductor 21, the 22nd insulated conductor 22, the 23rd insulated conductor 23, and the second non-insulated conductor 24 in the left-handed direction. It is formed by being twisted. The third conductor bundle 30 is T (3) times per unit length in the longitudinal direction of the conductor bundle in the order of the 31st insulated conductor 31, the 32nd insulated conductor 32, the 33rd insulated conductor 33, and the third non-insulated conductor 34 in the left-handed direction. It is formed by being twisted. The fourth conductor bundle 40 is T (4) times per unit length in the longitudinal direction of the conductor bundle in the order of the 41st insulated conductor 41, the 42nd insulated conductor 42, the 43rd insulated conductor 43 and the fourth non-insulated conductor 44 in the left-handed direction. It is formed by being twisted.

  The frequency AF (1) at which the same surface appears in a cross section perpendicular to the longitudinal direction in the first conductor bundle 10 is equal to the number of twists T (1) per unit length of the first conductor bundle 10. The frequency AF (2) at which the same surface appears in a cross section perpendicular to the longitudinal direction is equal to the number of twists T (2) per unit length of the second conductor bundle 20. Further, the frequency AF (3) at which the same surface appears in the cross section perpendicular to the longitudinal direction in the third conductor bundle 30 is equal to the number of twists T (3) per unit length of the third conductor bundle 30, and the fourth conductor bundle The frequency AF (4) at which the same surface appears in a cross section perpendicular to the longitudinal direction at 40 is equal to the number of twists T (4) per unit length of the fourth conductor bundle 40.

  In one example, the twist pitch L (1) of the first conductor bundle 10 is 4 mm, the twist pitch L (2) of the second conductor bundle 20 is 6 mm, and the twist pitch L (3) of the third conductor bundle 30 is 7 mm, and the twist pitch L (4) of the fourth conductor bundle 40 is 9 mm. Each of the number of twists T (1) to T (4) per unit length of the first conductor bundle 10 to the fourth conductor bundle 40 is the twist pitch L (1) to the first conductor bundle 10 to the fourth conductor bundle 40. Defined as the reciprocal of L (4). That is, the number of twists T (1) per unit length of the first conductor bundle 10 when the twist pitch L (1) is 4 mm is 250 times / m, and the second when the twist pitch L (2) is 6 mm. The number of twists T (2) per unit length of the conductor bundle 20 is 166 times / m. The number of twists T (3) per unit length of the third conductor bundle 30 when the twist pitch L (3) is 7 mm is 142 times / m, and the fourth when the twist pitch L (4) is 9 mm. The number of twists T (4) per unit length of the conductor bundle 40 is 111 times / m. Further, in each of the first conductor bundle 10 to the fourth conductor bundle 40, the frequencies AF (1) to AF (4) at which the same surface appears in the cross section perpendicular to the longitudinal direction of the conductor bundle are the frequency per unit length. The number of twists is the same as T (1) to T (4). Here, the state in which the cross section perpendicular to the longitudinal direction is the same plane requires that the phase relationship of the cross sections be the same in addition to the same positional relationship between the insulated conductor and the non-insulated conductor. is there. Since each of the first conductor bundle 10 to the fourth conductor bundle 40 twists the insulated conductor and the non-insulated conductor at the same twist pitch along the longitudinal direction of the conductor bundle, it is between the insulated conductor and the non-insulated conductor. The positional relationship does not change over the longitudinal direction. However, in each of the first conductor bundle 10 to the fourth conductor bundle 40, the phase of the cross section perpendicular to the longitudinal direction gradually changes with the twist pitch as one period. Therefore, here, although the positional relationship between the insulated conductor and the non-insulated conductor is the same, if the phase of the cross section does not match, the cross section perpendicular to the longitudinal direction is not considered to be the same plane.

  FIG. 4 is a diagram conceptually showing the progress of the phase relationship until the same cross section appears in each cross section in the longitudinal direction in a state where the conductor bundle is twisted. 4 (a) to 4 (i), the upper stage shows a state before the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30 and the fourth conductor bundle 40 are twisted together, The lower stage shows a state after the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30, and the fourth conductor bundle 40 are twisted together. The twist pitches L (1) to L (4) of the first conductor bundle 10 to the fourth conductor bundle 40 are, for example, 4 mm, 6 mm, 7 mm, and 9 mm, respectively. Moreover, the twist pitch L1 in the longitudinal direction of the conductor group in which the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30, and the fourth conductor bundle 40 are twisted together is 60 mm. FIG. 4A shows a state in which the phases of the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30, and the fourth conductor bundle 40 match. Each of FIGS. 4 (b) to 4 (i) shows a state at a position 30 mm, 45 mm, 60 mm, 100 mm, 200 mm, 220 mm, 240 mm and 252 mm away from the position shown in FIG. 4 (a). In each of FIGS. 4 (a) to 4 (i), the numbers surrounded by circles correspond to the numbers of the conductor bundles, and the numbers surrounded by circles and Y-shaped symbols (hereinafter referred to as symbols “Y”). Direction) is changed corresponding to the change in the phase of the cross section of each conductor bundle. That is, the first conductor bundle 10 is indicated by a circle 1, the second conductor bundle 20 is indicated by a circle 2, the third conductor bundle 30 is indicated by a circle 3, and the fourth conductor bundle 40 is indicated by a circle 4. Here, each of the circles 1 to 4 indicates a notation in which numbers “1” to “4” are arranged inside the circle, respectively. 4A to 4I, the symbol “Y” indicates the phase of each of the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30, and the fourth conductor bundle 40 in the cross section. Indicates. When each of the circles 1 to 4 is clamped upward and the symbol “Y” stands upright, the phase is “0”, and each of the circles 1 to 4 is clamped to the right and the symbol “Y” is The phase when tilted 90 degrees to the right is “π / 2”. Further, when the circles 1 to 4 are sandwiched downward and the symbol “Y” is inverted, the phase is “π”, and each of the circles 1 to 4 is sandwiched on the left side and the symbol “Y”. "Is tilted 90 degrees to the left, the phase is" 3π / 2 ".

  4A to 4I, the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30, and the fourth conductor bundle 40 each have a twist pitch L (1 ) To L (4) are different from each other, the phases appearing in the respective cross sections are different. All of the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30 and the fourth conductor bundle 40 until the length corresponding to the least common multiple of the twist pitches L (1) to L (4) reaches 252 mm. Cross sections having the same phase do not appear.

  When each of the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30, and the fourth conductor bundle 40 is twisted at the twist pitch L1, as shown in the lower stages of FIGS. 4 (a) to 4 (i). The phase appearing in each cross section further changes according to the twist pitch L1. That is, when twisted at the twist pitch L1, the first conductor bundle 10, the second conductor bundle 20, and the third conductor bundle until the minimum common multiple of the twist pitches L (1) to L (4) and L1 is 1260 mm. A cross section in which all 30 and the fourth conductor bundle 40 have the same phase does not appear.

  As shown in FIG. 1 described above, the protective tube 50 is composed of a flexible tube made of metal (stainless steel in the present embodiment) and twisted together, the first conductor bundle 10, the second conductor bundle 20, and the third conductor. It arrange | positions so that the outer peripheral surface of the bundle | flux 30 and the 4th conductor bundle 40 may be covered via an EPTFE tape not shown. The sheath 60 is a protective coating layer formed of polyethylene and is disposed on the outer periphery of the protective tube 50.

(Manufacturing method of the multi-core cable according to the embodiment)
FIG. 5 is a flowchart showing a manufacturing process of the multi-core cable 1, and FIG. 6 shows the first conductor bundle 10 to the fourth conductor bundle 40 when the first conductor bundle 10 to the fourth conductor bundle 40 are twisted. It is a figure which shows the twist machine used when twisting collectively. Moreover, FIG. 7 is a figure which shows the operation state of the twister shown in FIG.

  First, each of the first conductor bundle 10 to the fourth conductor bundle 40 is twisted (S101). Next, the first conductor bundle 10 to the fourth conductor bundle 40 twisted in S101 are twisted together to form a conductor group (S102). Here, the conductor group corresponds to the entire n conductor bundles.

  The twister 80 includes a first rotary plate 81, a second rotary plate 82, a third rotary plate 83, a rotary shaft 84, a throttle port 85, and four unwinding devices 86 (only three are shown). Have. Each of the first rotating plate 81, the second rotating plate 82, and the third rotating plate 83 is rotatably disposed around the rotation shaft 84. The first rotating plate 81 rotatably supports the four unwinding devices 86 at positions shifted from each other by 90 degrees on one surface. The second rotating plate 82 has four second cable through holes 87 formed therein. The third rotating plate 83 has twelve third cable through holes 88 formed therein. Each of the twelve third cable through holes 88 is formed at a position closer to the rotation shaft 84 than the second cable through hole 87. Each of the four unwinding devices 86 is wound with an insulated conductor, a non-insulated conductor, or a conductor bundle in which the insulated conductor and the non-insulated conductor are twisted. The leading ends of the conductors wound around each of the four unwinding devices 86 are arranged so as to penetrate the throttle port 85 via the second cable through port 87 and the third cable through port 88. The first rotary plate 81, the second rotary plate 82, and the third rotary plate 83 are rotated at the same predetermined rotational speed, and the tip end portion of the conductor disposed so as to penetrate the aperture port 85 is horizontally leveled at the predetermined speed. By moving in the direction, for example, four conductors can be twisted at a desired pitch.

  When the first conductor bundle 10 is twisted, the eleventh insulated conductor 11, the twelfth insulated conductor 12, the thirteenth insulated conductor 13 and the first non-insulated conductor 14 are wound around each of the four unwinding devices 86 and wound. It arrange | positions so that the front-end | tip of four conductors may penetrate the aperture opening 85. FIG. Then, the first rotating plate 81, the second rotating plate 82, and the third rotating plate 83 are rotated at a predetermined rotational speed so that the twist pitch L (1) is 4 mm, and the tip of the conductor is moved at a predetermined speed. To move horizontally. Further, when the first conductor bundle 10 to the fourth conductor bundle 40 are twisted together, the first conductor bundle 10 to the fourth conductor bundle 40 are wound around each of the four unwinding devices 86, and the wound four pieces It arrange | positions so that the front-end | tip of a conductor bundle may penetrate the aperture opening 85. FIG. Then, the first rotating plate 81, the second rotating plate 82, and the third rotating plate 83 are rotated at a predetermined rotational speed, and the tip end portion of the conductor bundle is moved in the horizontal direction at a predetermined speed.

  Next, the protective tube 50 is formed on the outer peripheral surfaces of the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30, and the fourth conductor bundle 40 twisted together (S103). In one example, the protective tube 50 is formed by weaving conductive wires around the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30, and the fourth conductor bundle 40 twisted together via an EPTFE tape. Is done. And the sheath 60 is formed in the outer peripheral surface of the protective tube 50 (S104). In one example, the sheath 60 is formed by extruding molten PVC onto the outer peripheral surface of the protective tube 50.

  The multi-core cable manufacturing method described with reference to FIGS. 5 to 7 is an example of the cable manufacturing method according to the present invention, and the cable according to the present invention may be manufactured by other manufacturing methods. . For example, the cable according to the present invention may employ a twister that rotates a throttle port that receives the cable that has been sent out, instead of the twister 80 in which the first to third rotating plates 81 to 83 rotate.

(Operational effect of the multi-core cable according to the embodiment)
The multi-core cable according to the embodiment reduces the periodicity in the longitudinal direction by randomly arranging the insulated conductors by collectively twisting a plurality of conductor bundles twisted at different twist pitches, Far end crosstalk can be reduced. The far-end crosstalk occurs when the signal lines are arranged in parallel in the longitudinal direction and the state where the capacitive coupling between the signal lines does not change continues. In the multi-core cable according to the embodiment, by disposing the insulated conductors at random, the capacitive coupling between the insulated conductors is varied in the longitudinal direction to reduce far-end crosstalk. That is, in the multi-core cable according to the embodiment, since the conductor bundles are not covered, they are twisted while interfering with each other when the conductor bundles are twisted together. For this reason, the cross section perpendicular to the longitudinal direction of the multi-core cable according to the embodiment has the same shape between the twist pitch of each conductor bundle and the length corresponding to the least common multiple of the twist pitch when the conductor bundle is twisted together. It will not be.

  For example, when the multi-core cable according to the embodiment is used as an ultrasonic probe cable, the frequency is about several MHz to several tens of MHz, and the cable length is about 4 to 5 m. When the multi-core cable according to the embodiment is used under such conditions, the twist pitch of each conductor bundle, and the length corresponding to the least common multiple of the twist pitch when the conductor bundle is twisted together should be about 5 to 10 m. That's fine. However, the twist pitch of each conductor bundle and the length corresponding to the least common multiple of the twist pitch when twisting the conductor bundle together are preferably 100 m or more. By making the twisted pitch of each conductor bundle and the length corresponding to the least common multiple of the twisted pitch when the conductor bundles are twisted together into 100 m or more, the shape of the cross section perpendicular to the longitudinal direction of the entire n conductor bundles Can be set to 0.01 times / m.

  Here, the term “frequency of occurrence of the same surface in a cross section perpendicular to the longitudinal direction” is defined based on the twist pitch of each conductor bundle and the twist pitch when the conductor bundle is twisted together, as will be described later. The The frequency at which the same surface appears in the cross section perpendicular to the longitudinal direction of each conductor bundle is defined as the reciprocal of the twist pitch of each conductor bundle. For example, the “frequency with which the cross-sectional shape perpendicular to the longitudinal direction is the same” of the first conductor bundle 10 in the multi-core cable 1 is 250 times because the twist pitch L (1) of the first conductor bundle 10 is 4 mm. / M. In addition, the frequency at which the same surface appears in the cross section perpendicular to the longitudinal direction in the entire n conductor bundles is the length corresponding to the twist pitch of each conductor bundle and the least common multiple of the twist pitches when the conductor bundles are twisted together. It is defined as the reciprocal of

  In the multi-core cable according to the embodiment, since the conductor bundle is not covered, the insulated conductor and the non-insulated conductor included in the conductor bundle fill the gap by the tension when the conductor bundle is twisted together. Will be arranged in close proximity. Since the size of the air gap formed in the multi-core cable is reduced by arranging the insulated conductor and the non-insulated conductor included in the conductor bundle close to each other, the diameter of the multi-core cable according to the embodiment is reduced.

In the multi-core cable according to the embodiment, each of the conductor bundles has at least one insulated conductor and at least one non-insulated conductor. Since each of the conductor bundles has at least one of the insulated conductor and the non-insulated conductor, the minimum distance between each of the plurality of insulated conductors and each of the plurality of non-insulated conductors is shorter than a predetermined length. can do. In the multi-core cable according to the embodiment, the ratio of the number of insulated conductors to the number of non-insulated conductors in each conductor bundle is preferably in the range of 2: 3 to 4: 1. By setting the ratio of the number of insulated conductors to the number of non-insulated conductors in each conductor bundle in the range of 2: 3 to 4: 1, the multi-core cable according to the embodiment has a variation in the capacitance of the insulated conductors. Can be small. The multi-core cable according to the embodiment can prevent a decrease in transmission performance due to an increase in noise and reflected waves due to characteristic impedance mismatch by reducing variations in capacitance of the insulated conductor.
Further, the ratio of the number of insulated conductors to the number of non-insulated conductors is in a range of 2: 3 or more and less than 1: 1, and the ratio of the average value of the diameters of the insulated conductors and the average value of the diameters of the non-insulated conductors is By setting the ratio in the range of 1.2: 1 or more and 4: 1 or less, the number of non-insulated conductors paired with the insulated conductors can be increased, so that the effect of reducing crosstalk can be improved. The ratio of the average value of the diameter of the conductor and the average value of the diameter of the non-insulated conductor is in the range of more than 1: 1 and 4: 1 or less, so the average value of the diameter of the insulated conductor and the average of the diameter of the non-insulated conductor Compared with a value ratio of 1: 1 or less, the overall outer diameter of all the insulated conductors and non-insulated conductors can be made smaller, and the cable can be made thinner.

(Modification of multi-core cable according to the embodiment)
The multi-core cable 1 has four conductor bundles in which the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30, and the fourth conductor bundle 40 are twisted together. The cable may have a plurality of conductor bundles. That is, the multi-core cable according to the embodiment may have two or three conductor bundles twisted together, or may have five or more conductor bundles twisted together. In the multicore cable according to the embodiment, a core of the multicore cable may be formed by twisting a plurality of conductor groups obtained by twisting n conductor bundles together. That is, the multi-core cable according to the embodiment may be a cable twisted over three or more layers.

  In the multi-core cable 1, each of the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30, and the fourth conductor bundle 40 is formed by twisting three insulated conductors and one non-insulated conductor. Is formed. However, in the multicore cable according to the embodiment, each of the plurality of conductor bundles has at least one insulated conductor and at least one non-insulated conductor, and the number of insulated conductors in each of the conductor bundles is not insulated. The ratio of the number of conductors may be in the range of 2: 3 to 4: 1. In the multi-core cable according to the embodiment, the number of insulated conductors and the number of non-insulated conductors included in the conductor bundle may be different for each conductor bundle.

  In the multi-core cable 1, the twist pitches L (1) to L (4) of the first conductor bundle 10 to the fourth conductor bundle 40 are 4 mm, 6 mm, 7 mm, and 9 mm, respectively. The twist pitch L1 when the fourth conductor bundle 40 is twisted together is 60 mm. However, in the multi-core cable according to the embodiment, at least one of the twist pitches L (N) (N = 1 to n) of the n conductor bundles may be different from the others. On the other hand, L (N) so that the least common multiple of the twist pitch L (N) (N = 1 to n) of the n conductor bundles and the twist pitch L1 when the n conductor bundles are twisted together is larger. ) And L1, the insulated conductors can be randomly arranged over a longer distance. In the multi-core cable according to the embodiment, any of the twist pitches L (N) (N = 1 to n) of the n conductor bundles does not have a constant period and extends in the length direction. It may be formed to vary.

  Moreover, in the multi-core cable 1, from the viewpoint of flexibility and durability, the twist direction of each conductor bundle and the twist direction when the conductor bundle is twisted together are the same, but in the multi-core cable according to the embodiment, The twist direction of some conductor bundles may be opposite to the twist direction of other conductor bundles and the twist direction in which conductor bundles are twisted together. In the multi-core cable according to the embodiment, some of the conductor bundles may not be twisted. When the twist direction of some conductor bundles is opposite to the twist direction of other conductor bundles and the twist direction of twisting the conductor bundles together, the twist pitch of the conductor bundle twisted in the opposite direction is the twist pitch of the other conductor bundles. The pitch is very large compared to the pitch. By making the twisting pitch of the conductor bundle twisted in the opposite direction very large, when the conductor bundle is twisted together, the conductor bundle twisted in the opposite direction twists while interfering with other conductor bundles. Will be. Thereby, the insulated conductor of the conductor bundle twisted in the opposite direction can reduce the periodicity of the distance between insulated conductors in the longitudinal direction similarly to the insulated conductors of other conductor bundles.

  In the multi-core cable 1, the diameters of the non-insulated conductors of the first conductor bundle 10, the second conductor bundle 20, the third conductor bundle 30, and the fourth conductor bundle 40 are larger than the diameter of the core material of the insulated conductor. The diameter of the insulated conductor may be smaller than the diameter of the core material of the insulated conductor. However, in the multicore cable according to the embodiment, the combined resistance of the non-insulated conductor is preferably larger than the combined resistance of the insulated conductor. Here, the combined resistance of the non-insulated conductor is the resistance value when the non-insulated conductors included in the multi-core cable of a predetermined length are connected in parallel, and the combined resistance of the insulated conductor is the combined resistance of the non-insulated conductor. It is the resistance value when the insulated conductors of the same multi-core cable as the measured cable are connected in parallel.

(Determination method of “frequency of appearance of the same surface in a cross section perpendicular to the longitudinal direction”)
FIG. 8 is a flowchart showing a process for determining “frequency of appearance of the same surface in a cross section perpendicular to the longitudinal direction”. Each of FIGS. 9, 10 (a) and 10 (b) is “cross section perpendicular to the longitudinal direction”. It is a figure explaining the process which determines "the frequency that the same surface appears in". In FIG. 10A, the same conductor bundle is hatched in the same manner. FIG. 10B is an enlarged view of a portion surrounded by a circle indicated by an arrow A in FIG.

  As shown in FIG. 8, first, the operator prepares a cable used for determining “frequency with which the same plane appears in a cross section perpendicular to the longitudinal direction” (S201), and at least a part of the cable is a desired one. The cable is fixed so as to extend in the horizontal direction over the distance (S202). Next, the operator removes the sheath of the cable (S203), and then removes the outer shield (S204), thereby taking out the core of the cable (S205). Here, the core used for determining “frequency with which the same surface appears in a cross section perpendicular to the longitudinal direction” will be described as being twisted over three layers. That is, as shown in FIG. 9, the core formed by being twisted over three layers is obtained by twisting an insulated conductor and a non-insulated conductor with a small twist pitch L (1) or L (2) 4 Four conductor groups are formed by twisting one conductor bundle with medium twist pitch L1 and further twisting with a large twist pitch L0. The twister 80 shown in FIG. 6 is used when a conductor bundle is formed by a small twist, when a conductor group is formed by a medium twist, and when a core is formed by a large twist.

  Next, the operator measures the large twist pitch L0 when the four conductor groups are twisted (S206). The large twist pitch L0 is measured by measuring the interval at which the same conductor group appears in the longitudinal direction of the core taken out in S205. In addition, since the length of the large twist pitch L0 may change for each position of the core, the intervals at which the same conductor group appears at a plurality of positions for a plurality of conductor groups are measured, and the average value of the measured values Is preferably a large twist pitch L0.

  Next, the operator measures the medium twist pitch L1 when the four conductor bundles are medium twisted (S207). The medium twist pitch L1 is measured by measuring the interval at which the same conductor bundle appears in the winding direction of the conductor group in which each of the medium twist conductor groups is largely twisted. In addition, since the length of the medium twist pitch L1 may change for each position of the core, the intervals at which the same conductor bundle appears at a plurality of positions for each conductor group are measured, and the average value of the measured values is calculated. A medium twist pitch L1 is preferable.

  Next, the operator measures the twisting pitches L (1) and L (2) when the four conductors are twisted (S208). The small twist pitches L (1) and L (2) are measured by measuring the intervals at which the same insulated conductor or non-insulated conductor appears in the longitudinal direction of the conductor bundle. In addition, since the length of the small twist pitches L (1) and L (2) may change for each conductor position, the same insulated conductor or non-insulated conductor appears at a plurality of positions for each conductor bundle. It is preferable to measure the distance to be measured and set the average value of the measured values to the small twist pitches L (1) and L (2).

  Next, the operator determines the frequency with which the same surface appears in the cross section perpendicular to the longitudinal direction for each conductor bundle (S209). The operator determines the reciprocals of the small twist pitches L (1) and L (2) measured in S208 as the frequency at which the same surface appears in the cross section perpendicular to the longitudinal direction. The frequency at which the same surface appears in the cross section perpendicular to the longitudinal direction of the conductor bundle whose small twist pitch is measured as L (1) in S208 is the reciprocal of the small twist pitch L (1). The frequency at which the same surface appears in the cross section perpendicular to the longitudinal direction of the conductor bundle whose small twist pitch is measured as L (2) in S208 is the reciprocal of the small twist pitch L (2).

  Then, the operator determines the frequency with which the same surface appears in the cross section perpendicular to the longitudinal direction in the entire conductor group formed of the four conductor bundles (S210). The operator sets the reciprocal of the least common multiple of the medium twist pitch L1 measured in S207 and the small twist pitch L (1) and L (2) measured in S208 to be perpendicular to the longitudinal direction of the four conductors as a whole. This is determined as the frequency at which the same surface appears in a simple cross section.

Example 1
Next, the crosstalk of the eight cables of the comparative example, the first example, the second example, the third example, the fourth example, the fifth example, the sixth example, and the seventh example is described. Compare. Each of these cores is formed of three layers of four conductor bundles, four conductor groups, and cores. In each of these cables, each of the four conductor bundles is formed by twisting four insulated conductors and one non-insulated conductor in the comparative example and the first example, and in the second example, Four insulated conductors and two non-insulated conductors are formed by twisting, and in the third and sixth embodiments, two insulated conductors and three non-insulating conductors are twisted and formed. The fourth, fifth and seventh embodiments are formed by twisting four insulated conductors and six non-insulated conductors.
Each of the four conductor groups is formed by twisting four conductor bundles. Each core of the cable twisted over three layers is formed by twisting four conductor groups. The size of the core material of the insulated conductors of the three cables of the comparative example, the first example, the second example and the third example is 42 AWG (7 twists, outer diameter 0.075 mm), and the thickness is 0.0225 mm. It is insulated and the size of the non-insulated conductor is 38 AWG (outer diameter 0.12 mm). In the fourth and sixth embodiments, the size of the core material of the insulated conductor is 42 AWG (7 twists, outer diameter 0.075 mm) and is insulation-coated with a thickness of 0.0225 mm, and the size of the non-insulated conductor is 42 AWG ( The outer diameter is 0.075 mm). In the fifth embodiment, the size of the core material of the insulated conductor is 44 AWG (7 twists, outer diameter 0.06 mm) and is coated with a thickness of 0.03 mm, and the size of the non-insulated conductor is 44 AWG (outer diameter 0.06 mm). mm). In the seventh embodiment, the size of the core material of the insulated conductor is 42 AWG (7 twists, outer diameter 0.075 mm) and is insulation-coated with a thickness of 0.11 mm, and the size of the non-insulated conductor is 42 AWG (outer diameter 0.075 mm). mm).
In the comparative example and the first example, each of the conductor bundles has four insulated conductors and one non-insulated conductor, and the average value of the distance between each of the insulated conductors and the non-insulated conductor is The diameter of the non-insulated conductor is 1.3 times or less. That is, in the comparative example and the first embodiment, the average value of values obtained by dividing the shortest distance from the center of each insulated conductor to the surface of the adjacent non-insulated conductor by the distance from the center of the insulated conductor to the outermost surface of the insulated conductor is 1 to 1.3. In the second embodiment, each of the conductor bundles has four insulated conductors and two non-insulated conductors, and the average value of the distance between each of the insulated conductors and the non-insulated conductor is non-insulated. It is 1.3 times or less the diameter of the conductor. In the third and sixth embodiments, each conductor bundle has two insulated conductors and three non-insulated conductors, and the average distance between each of the insulated conductors and the non-insulated conductor is The diameter of the non-insulated conductor is 1.3 times or less. In the fourth, fifth and seventh embodiments, each of the conductor bundles has four insulated conductors and six non-insulated conductors, and the distance between each of the insulated conductors and the non-insulated conductor is The average value is 1.3 times or less the diameter of the non-insulated conductor. That is, also in the second, third, fourth, fifth, sixth, and seventh embodiments, the shortest distance from the center of each insulated conductor to the surface of the adjacent non-insulated conductor is set from the center of the insulated conductor to the insulated conductor. The average value divided by the distance to the outermost surface is in the range of 1 to 1.3. Tables 1 to 5 show the twist pitches of the comparative example, the first example, the second example, the third example, the fourth example, and the fifth example. In Tables 1 to 5, S represents the number of insulated conductors, and G represents the number of non-insulated conductors.

  In the comparative example, the four conductor bundles are each formed with a small twist pitch of 10 mm, the four conductor groups are formed with a medium twist pitch of 25 mm, and the core is formed with a large twist pitch of 80 mm. Therefore, in the comparative example, the same surface appears in the cross section in the longitudinal direction of the core in the vicinity of 400 mm, which is the least common multiple of the pitch.

  In the first embodiment, as shown in Table 2, each of the four conductor bundles is different in the small twist pitches L (1) to L (4), and the length corresponding to the least common multiple is increased, and the longitudinal direction Are formed at a small twist pitch so that the frequency of appearance of the same surface in a cross section perpendicular to the angle is small. In such a configuration, in the longitudinal direction of the core, the same surface appears in the cross section at a value (mm) exceeding 10 17 that is the least common multiple of the pitches shown in Table 2. As described above, in the first embodiment, the least common multiple of the small twist pitches L (1) to L (4) and the medium twist pitch L1 is larger than that of the comparative example, and the length of the four conductors is increased in the longitudinal direction. It is formed with a medium twist pitch so that the frequency of appearance of the same surface in a cross section perpendicular to is small. Further, in the first embodiment, the core is formed with a large twist pitch with a larger prime number than each of the medium twist pitches.

  In the second embodiment, as shown in Table 3, each of the four conductor bundles is formed with the same small twist pitch as in the first embodiment. Further, in the second embodiment, the four conductors as a whole have the same cross-section perpendicular to the longitudinal direction by twisting at a medium twist pitch that is a prime number larger than each of the medium twist pitch L1 of the first embodiment. The frequency of appearance of the surface is reduced. In the second embodiment, the core is formed with a larger twist pitch than that of the first embodiment.

  Also in the third to seventh embodiments, as shown in Tables 4 and 5, each of the four conductor bundles is formed with the same small twist pitch as in the first embodiment. In the third to seventh embodiments, the four conductors as a whole are perpendicular to the longitudinal direction by twisting at a medium twist pitch that is a prime number larger than the medium twist pitch L1 of each of the first embodiments. It is formed so that the frequency of appearance of the same surface in the cross section is reduced. In the third to seventh embodiments, the core is formed with a larger twist pitch than that of the first embodiment.

FIG. 11 is a diagram illustrating crosstalk frequency characteristics of the eight cables of the comparative example, the first example to the seventh example. In FIG. 11, the horizontal axis represents the signal frequency [MHz], and the vertical axis represents the crosstalk magnitude [dB]. The graph indicated by the arrow A indicates the characteristics of the comparative example, the graph indicated by the arrow B indicates the characteristics of the first embodiment, the graph indicated by the arrow C indicates the characteristics of the second embodiment, and the graph indicated by the arrow D. Indicates the characteristics of the third embodiment, the graph indicated by the arrow E indicates the characteristics of the fourth embodiment, the graph indicated by the arrow F indicates the characteristics of the fifth embodiment, and the graph indicated by the arrow G indicates the sixth embodiment. The graph indicated by the arrow H indicates the characteristics of the seventh embodiment.
Here, in the first to seventh embodiments, the outer diameter of the entire conductor in a state where all of the respective insulated conductors and specific insulated conductors are twisted together is 1.95 mm in the first embodiment, and 2.1 in the second embodiment. mm, 1.6 mm in the third embodiment, 2.1 mm in the fourth embodiment, 1.8 mm in the fifth embodiment, 1.5 mm in the sixth embodiment, and 1.6 mm in the seventh embodiment. As described above, even in the fourth and fifth embodiments in which the total number of conductors is larger than that in the second embodiment, the ratio of the average value of the diameter of the insulated conductor and the average value of the diameter of the non-insulated conductor is By setting 8: 5 in the embodiment, 2: 1 in the fifth embodiment, and approximately 4: 1 in the seventh embodiment, the number of insulated conductors is the same as that in the first and second embodiments. Even in a state where the number of non-insulated conductors is large, the overall outer diameter of all the insulated conductors and non-insulated conductors can be made equal to or less than those of the first and second embodiments, and the small diameter of the cable It was confirmed that the effect of reducing crosstalk was achieved.

  As shown in the figure, the third embodiment (D) has the lowest crosstalk, and then the sixth embodiment (G), the fourth embodiment (E), the seventh embodiment (H), and the fifth embodiment. It becomes large in order of an Example (F), a 2nd Example (C), a 1st Example (B), and a comparative example (A). In the cables of the first to fifth embodiments, the crosstalk is less than 20 [dB] in any band up to about 20 [MHz]. Thus, by increasing the length corresponding to the least common multiple between the small twist pitch and the medium twist pitch, the frequency of occurrence of the same surface in the cross section perpendicular to the longitudinal direction in the conductor and the conductor bundle is reduced. Talk can be reduced.

  In addition, in each of the six cables of the comparative example, the first example, the second example, the third example, the fourth example, and the fifth example, the twist is performed in the order of small twist, medium twist, and large twist. Although the pitch is formed to be large, in the cable according to the embodiment, it is not necessary to increase the twist pitch every time the level is raised. In the cable according to the embodiment, for example, one of the twist pitches of the small twist may be larger than the twist pitch of the medium twist.

(Example 2)
Next, crosstalk is compared when the ratio between the number of non-insulated conductors and the number of insulated conductors is changed. Here, the ratio of the number of non-insulated conductors to the number of insulated conductors is 0:16, 1:16, 1: 8 (2:16), 1: 4 (4:16), 1: 3 (6 : 18), 1: 2 (8:16) and 1: 1 (16:16). The numbers in parentheses above represent the ratio between the number of non-insulated conductors and the number of insulated conductors when the number of insulators is unified to 16. Here, the size of the core material of the insulated conductor is 42 AWG, and the size of the non-insulated conductor is 38 AWG.

  FIG. 12 is a diagram illustrating a change in crosstalk when the ratio of the number of insulated conductors included in the cable and the number of non-insulated conductors is changed when the signal frequency is 20 [MHz]. In FIG. 12, the horizontal axis indicates the ratio between the number of insulated conductors and the number of non-insulated conductors, and the vertical axis indicates the magnitude [dB] of crosstalk.

  When the ratio between the number of insulated conductors included in the cable and the number of non-insulated conductors is 0:16, the crosstalk becomes about -10 [dB], and the number of insulated conductors included in the cable and the number of non-insulated conductors. When the ratio is 1: 4, the crosstalk is about -20 [dB]. Further, when the ratio of the number of insulated conductors included in the cable to the number of non-insulated conductors is 1: 1, the crosstalk is about −35 [dB].

  FIG. 13A shows a signal state when the crosstalk is smaller than −20 [dB], and FIG. 13B shows a signal state when the crosstalk is larger than −20 [dB].

  As shown in FIG. 13A, when the crosstalk is larger than −20 [dB], the signal bandwidth becomes wide, and good signal characteristics cannot be obtained. On the other hand, as shown in FIG. 13B, when the crosstalk is smaller than −20 [dB], the signal bandwidth becomes narrow, and good signal characteristics can be obtained. Therefore, as shown in the first and second embodiments in FIG. 11 described above, it was confirmed that good signal characteristics were obtained up to 20 [MHz].

(Example 3)
Next, compare the characteristic impedance and loss when changing the value obtained by dividing the distance from the center of the insulated conductor to the surface of the adjacent non-insulated conductor by the distance from the center of the insulated conductor to the outermost surface of the insulated conductor. . Table 6 shows the values when the distance (L) from the center of the insulated conductor to the surface of the adjacent non-insulated conductor is divided by the distance (l) from the center of the insulated conductor to the outermost surface of the insulated conductor. Changes in characteristic impedance (Zo) and loss (loss) are shown. Here, when (L / l) is 1, it indicates that the non-insulated conductor is in contact with the insulated conductor, and when (L / l) is 2, it is between the non-insulated conductor and the insulated conductor. It indicates that the distance is twice the distance from the center of the insulated conductor to the outermost surface of the insulated conductor.

  The loss of 0% when (L / l) is 1 becomes 10% when (L / l) is 1.3. When a multi-core cable is used as an ultrasonic probe cable or the like, if the loss exceeds 10%, it is considered that good transmission performance cannot be obtained.

  Table 6 shown below shows respective combined resistances of the insulated conductor and the non-insulated conductor when a silver-plated tin-containing copper alloy is used as the core material of the insulated conductor and the non-insulated conductor. Here, each of the combined resistance of the insulated conductor and the non-insulated conductor indicates a resistance value per unit length when the insulated conductor and the non-insulated conductor included in the cable are respectively connected in parallel. For example, when the ratio of the number of non-insulated conductors to the number of insulated conductors is 1:16, the combined resistance of the non-insulated conductors indicates the resistance value per unit length of one non-insulated conductor, and the combined number of the insulated conductors The resistance indicates a resistance value per unit length when 16 insulated conductors are connected in parallel.

Next, the multicore cable according to the present embodiment is divided into the presence or absence of a protective tube, and the result when a side pressure fracture test is performed on each cable is shown. Here, the side pressure rupture test is a method in which a cable is placed on an inspection table, a pressure tool having a diameter of 150 mm is pressed thereon, and the maximum load until the conductor is disconnected is measured. According to this, the maximum load is 2856 kgf when the protective tube 50 is provided, but 1085 kgf when the protective tube 50 is not provided. By providing the protective tube, durability against the impact from the radial direction of the cable is achieved. Therefore, the range under the usage condition as an ultrasonic probe cable can be widely and safely used in indoor / outdoor or fixed / moving conditions, and versatility can be improved.

1 Multi-core cable 10, 20, 30, 40 Conductor bundle 11-13, 21-23, 31-33, 41-43 Insulated conductor 14, 24, 34, 44 Non-insulated conductor 50 Protective tube 60 Sheath

Claims (8)

Multi-core cable,
In a state where the multi-core cable is inserted, a bendable metal protective tube, and
The multi-core cable has a conductor bundle of n protective tubes, and each of the n conductor bundles has at least one insulated conductor and at least one non-insulated conductor in the longitudinal direction. The frequency of appearance of the same surface in the vertical cross section is AF (N) (N = 1 to n) per unit length, and at least one of the AF (N) (N = 1 to n) is different from the others, The ratio of the number of the insulated conductors to the number of the non-insulated conductors in each of the n conductor bundles is in the range of 2: 3 to 4: 1, and the pair of the insulated conductor and the non-insulated conductor is not fixed. The multi-conductor cable is characterized in that each insulated conductor is paired with a non-insulated conductor of the same conductor bundle and / or a non-insulated conductor of a different conductor bundle.   The multi-core cable according to claim 1, wherein a ratio of the number of the insulated conductors to the number of the non-insulated conductors in each of the n conductor bundles is in a range of 1: 1 to 4: 1. The ratio of the number of the insulated conductors and the number of the non-insulated conductors in each of the n conductor bundles is in a range of 2: 3 or more and less than 1: 1.
The ratio of the average value of the diameter of the insulated conductor and the average value of the diameter of the non-insulated conductor of the n conductor bundles is in a range of 1.2: 1 or more and 4: 1 or less. The listed multi-core cable.   In a cross section perpendicular to the longitudinal direction, the shortest distance from the center of each insulated conductor of the n conductor bundles to the surface of the non-insulated conductor adjacent thereto is the distance from the center of the insulated conductor to the outermost surface of the insulated conductor. The multi-core cable according to claim 1, wherein an average value of the divided values is in a range of 1 to 1.3.   5. The multi-core cable according to claim 1, wherein the frequency of appearance of the same surface in a cross section perpendicular to the longitudinal direction of the n conductor bundles is 0.01 times / m or less.   6. The combined resistance when the insulated conductors of the n conductor bundles are connected in parallel is larger than the combined resistance when the non-insulated conductors of the n conductor bundles are connected in parallel. A multi-core cable according to claim 1. Multi-core cable,
In a state where the multi-core cable is inserted, a bendable metal protective tube, and
The multi-core cable has n conductor bundles, and each of the n conductor bundles has at least one insulated conductor and at least one non-insulated conductor, and the at least one conductor bundle. The insulated conductor and the at least one non-insulated conductor are twisted T (N) (N = 1 to n) times per unit length, and the n conductor bundles are twisted T1 times per unit length. , At least one of the T (N) (N = 1 to n) is different from the others, and the ratio of the number of the insulated conductors to the number of the non-insulated conductors in each of the n conductor bundles is 2: A range of 3-4: 1, where the pairs of insulated conductors and non-insulated conductors are not fixed and each insulated conductor is paired with a non-insulated conductor of the same conductor bundle and / or a non-insulated conductor of a different conductor bundle. A multi-core cable characterized by N conductor bundles each having at least one insulated conductor and at least one non-insulated conductor, the at least one insulated conductor and the at least one non-insulated conductor in the longitudinal direction of the conductor bundle. T (N) (N = 1 to n) twists per unit length,
Twist T1 times per unit length in the longitudinal direction of the conductor group as a conductor group in which the twisted n conductor bundles are combined,
At least one of the T (N) (N = 1 to n) is different from the others,
A ratio of the number of the insulated conductors to the number of the non-insulated conductors in each of the n conductor bundles is in a range of 2: 3 to 4: 1;
A pair of insulated conductors and non-insulated conductors is not fixed, and each insulated conductor manufactures a multi-core cable that is paired with a non-insulated conductor of the same conductor bundle and / or a non-insulated conductor of a different conductor bundle. Manufacturing process,
A method of manufacturing a multi-core cable with a protective tube, comprising: a protective tube insertion step of inserting the multi-core cable manufactured by the multi-fiber cable manufacturing step into a bendable metal protective tube.