1. Technical Field
The present invention relates to a multi-core coaxial cable with an attached connecting member, and to a method for manufacturing thereof.
2. Background Art
Japanese Patent Application No. 2003-123552 (Patent Citation 1) discloses a multi-core coaxial cable composed of a number of ultrafine coaxial cables, each of which has an inner conductor with outside diameter of approximately 0.15 mm or smaller covered by an insulator, an outer conductor disposed on the outside periphery of the insulator, and a jacket sheathing the outside of the outer conductor, and which are twisted together. In the ultrafine coaxial cables, there are provided parallel bonded portions and unbonded portions of given span.
Where a multi-core coaxial cable is to be connected to a connecting member such as a circuit board, terminal processing, which involves exposing the center conductor and the outer conductor of each coaxial cable from the cable sheath of the multi-core coaxial cable and connecting them to the circuit board by soldering, is carried out by a manual procedure. Where the multi-core coaxial cable is to be used in a medical device such as an endoscope, in certain instances it may be necessary to shorten the distance from the end portion of the cable sheath to the circuit board to a dimension of about 2 to 3 mm, for example, to limit exposure of the coaxial cable as much as possible. In such instances, terminal processing of the coaxial cables by a manual procedure is difficult, and dimensional accuracy tends to be poor and the defect rate is high. It may be contemplated to carry out terminal processing by squeezing and moving the cable sheath to expose a greater processing length of the coaxial cables, and to subsequently return the sheath to its original place; however, for multi-core coaxial cables whose sheaths have high cohesive force, the sheath may not readily move, making terminal processing difficult.
It is accordingly an object of the present invention to provide a multi-core coaxial cable with an attached connecting member that affords ease of terminal processing, good dimensional accuracy, and a negligible defect rate, as well as a method for manufacturing thereof.
To attain this object, there is provided a connecting member-terminated multi-core coaxial cable that includes a multi-core coaxial cable, a connecting member, and a covering member. In this multi-core coaxial cable, the multi-core coaxial cable is composed of a plurality of coaxial cables collectively covered by a cable sheath, each of the cables being provided with an insulator, an outer conductor, and a sheath successively disposed in a coaxial arrangement around a center conductor. At one end portion of the multi-core coaxial cable, the plurality of coaxial cables are exposed from the cable sheath and arranged in parallel rows. The connecting member is connected to one end portion of the multi-core coaxial cable, and the center conductors and the outer conductors of the plurality of coaxial cables are conductively connected to the respective terminal portions of the connecting member. The covering member covers the periphery of the plurality of coaxial cables between the cable sheath and the connecting member, and is arranged such that distance from the end portion at the connecting member side of the covering member to the edge of the connecting member is 20 mm or less.
In the connecting member-terminated multi-core coaxial cable of the present invention, optionally, the plurality of coaxial cables are divided into a plurality of coaxial cable groups and arranged in respective parallel rows in a plurality of coaxial cable groups, the coaxial cable groups being connected to the connecting member in an overlapping manner. In this case, the outer conductor is preferably exposed in the same location in each of the plurality of coaxial cable groups, and is conductively connected in an integrated fashion to a ground terminal. In preferred practice, the distance from the end portion at the connecting member side of the covering member to the edge of the connecting member is 5 mm or less. One example of the covering member is a heat shrinkable tube formed from a heat shrinkable resin.
Another aspect of the present invention provides a method for manufacturing a connecting member-terminated multi-core coaxial cable having a multi-core coaxial cable and a connecting member, the multi-core coaxial cable having a plurality of coaxial cables collectively covered by a cable sheath. Each of the cables is provided with an insulator, an outer conductor, and a sheath successively disposed in a coaxial arrangement around a center conductor. The manufacturing method includes a sheath stripping step, an alignment step, a terminal processing step, a conductor connection step, and a covering attachment step. In the sheath stripping step, the cable sheath at the end portion is stripped to expose the plurality of coaxial cables. In the alignment step, the plurality of coaxial cables which are exposed are arranged in parallel rows. In the terminal processing step, the center conductors and the outer conductors of the plurality of coaxial cables are exposed. In the conductor connection step, the center conductors and the outer conductors of the coaxial cables are respectively conductively connected to terminal portions of the connecting member. In the covering attachment step, the covering member is attached to the periphery of the plurality of coaxial cables between the cable sheath and the connecting member, so that the distance from the end portion at the connecting member side to the edge of the connecting member is 20 mm or less.
In the method for manufacturing a connecting member-terminated multi-core coaxial cable of the present invention, preferably, in the alignment step, the plurality of coaxial cables are divided into a plurality of coaxial cable groups and arranged in respective parallel rows in the plurality of coaxial cable groups; and in the conductor connection step, the coaxial cable groups are connected to the connecting member in an overlapping state. Preferably, in the terminal processing step, the outer conductor is exposed in the plurality of coaxial cable groups in the same location on the connecting member. In the conductor connection step, the outer conductors are conductively connected in an integrated fashion to a ground terminal. In preferred practice, in the covering attachment step, the covering member is attached such that the distance from the end portion at the connecting member side of the covering member to the edge of the connecting member is 5 mm or less.
According to the connecting member-terminated multi-core coaxial cable of the present invention, coaxial cables which have been exposed from the cable sheath may be well protected by a covering member which has been disposed such that the distance from the end portion thereof to the connecting member is 20 mm or less. Also, according to the method for manufacturing a connecting member-terminated multi-core coaxial cable of the present invention, during terminal processing of the coaxial cables prior to installation of the covering member, the exposed length of the coaxial cables from the cable sheath is sufficiently great for the terminal processing procedure to take place efficiently. Therefore, operability during coaxial cable terminal processing may be significantly improved, dimensional accuracy subsequent to processing may be improved in the connecting member-terminated multi-core coaxial cable, and a negligible defect rate may be attained.
The embodiments of the present invention are described below with reference to the drawings. The drawings are intended for illustrative purposes, and are not limiting of the invention. In the drawings, in order to avoid redundant description, like symbols indicate like components. Dimensional proportions in the drawings are not necessarily accurate.
The end portion of the multi-core coaxial cable 11 is subjected to terminal treatment carried out as follows (see
The coaxial cables 21 are also subjected to terminal treatment carried out as follows. In each coaxial cable 21, the center conductor 31, the insulator 32, and the outer conductor 33 are exposed in a stepwise fashion in order from the distal end side. The exposed length of the coaxial cables 21 which make up the coaxial cable groups 42A, 42B, 42C differ by group, with the coaxial cable group 42A, the coaxial cable group 42B, and the coaxial cable group 42C having progressively shorter exposed length, in that order. More specifically as shown in
The circuit board may be reduced in width by dividing the plurality of coaxial cables 21 into a plurality of coaxial cable groups and overlapping the coaxial cable groups. During this process, the surface area of the circuit board may also be reduced by staggering in small increments the connection locations of the center conductors. Through such an arrangement, the dimensions of the circuit board may be reduced to a size that fits inside a narrow enclosure such as that used in an endoscope.
Meanwhile, in all of the coaxial cables 21, the outer conductors 33 are exposed at the same location in the length direction (the same location on the connecting member), and are conductively connected in an integrated fashion through soldering to a ground terminal portion (terminal portion) 52 formed by a wiring pattern disposed across the width direction of the circuit board 12. By so doing, the space required to solder the outer conductors to the ground terminal portion can be smaller. Optionally, the outer conductors 33 may be collectively urged into continuity with the ground terminal portion 52 of the circuit board 12 by a ground bar.
A covering tube (covering member) 61 is installed on an exposed portion A where the cable sheath 23 has been stripped from the multi-core coaxial cable 11 connected to the circuit board 12, in such a way as to cover the shield layer 22. The covering tube 61 is disposed in intimate contact around the exposed portion A. As shown in
In the multi-core coaxial cable 11, it is necessary for the coaxial cables to have prescribed length from the locations where they are disassembled to the locations where they are arrayed in parallel rows. During terminal processing of the coaxial cables 21 prior to installing the covering tube 61, the exposed length of the coaxial cables 21 from the cable sheath 23 may be made large enough that the terminal processing operation can take place efficiently. The coaxial cables 21 may be arrayed in parallel rows thereby. Additionally, operability in terminal processing of the coaxial cables 21 prior to installing the covering tube 61 can be significantly improved, dimensional accuracy subsequent to processing may be enhanced, and a negligible defect rate may be attained.
By positioning the covering tube 61 such that the distance from the end portion 61a thereof to the edge of the circuit board 12 is 20 mm or less, the coaxial cables 21 which have been exposed from the cable sheath 23 may be well protected. Moreover, movement in the lengthwise direction of the cable sheath 23 can be restricted by the covering tube 61, and the cable sheath 23 may be prevented from shifting out of place. By using the covering tube to cover the shield layer or coaxial cables again which were previously exposed by stripping the sheath, the distance from the edge of the circuit board to the cable sheath (covering tube) can be kept to 20 mm or less. By using this method, there may be produced multi-core coaxial cables in which the dimension from the stripped portion to the circuit board is 5 mm or less, such as about 2 to 3 mm, for example.
Next, the method for manufacturing the connecting member-terminated multi-core coaxial cable which includes the multi-core coaxial cable 11 connected to the circuit board 12 will be described. First, the as yet unshrunken covering tube 61 is slipped around the multi-core coaxial cable 11 from the end portion thereof through (
According to the embodiment of the manufacturing method described above, terminal processing of the coaxial cables 21 is carried out with the coaxial cables 21 sufficiently exposed from the cable sheath 23, whereby terminal processing of the coaxial cables 21 may be carried out easily, and multi-core coaxial cables 11 having excellent dimensional accuracy can be manufactured smoothly with a negligible defect rate.
Where the plurality of coaxial cables 21 are divided into a plurality of coaxial cable groups, the number of groups is not limited to that taught in the preceding embodiment. Optionally, the plurality of coaxial cables 21 may be positioned in a single row and connected to the circuit board 12 without being divided into a plurality of coaxial cable groups. Additionally, it is not essential to provide the shield layer 22. In this case, the covering tube 61 would directly cover the outside of the coaxial cables 21. Optionally, wrapping tape may be disposed around the plurality of coaxial cables 21, in which case the covering tube 61 would cover the outside of the coaxial cables 21 via the wrapping tape.
In the preceding embodiment, the present invention was described in terms of a multi-core coaxial cable connected at one end to a connecting member and a method for the manufacture thereof; however, the connecting member-terminated multi-core coaxial cable of the present invention may be connected at both ends to connecting members. While the connecting member was described as a circuit board 12 by way of example, the invention is applicable in instances where the connecting member is a connector, and the coaxial cables are connected to the connector.
The invention is useful as a connecting member-terminated multi-core coaxial cable in medical devices and the like.
Number | Date | Country | Kind |
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2009-243206 | Oct 2009 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2010/068239 | 10/18/2010 | WO | 00 | 10/26/2011 |
Publishing Document | Publishing Date | Country | Kind |
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WO2011/049028 | 4/28/2011 | WO | A |
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Number | Date | Country | |
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20120040556 A1 | Feb 2012 | US |