Cable for movable part and life prediction system

Abstract

The present invention provides a cable for a movable part containing a disconnection detection wire and a life prediction system that can be used to accurately predict the life of a cable. The cable (1) for a movable part includes a cable core wire (2) including a plurality of insulated wires (21), a braided shield (3) provided to cover the periphery of the cable core wire (2) and formed by a braided metal wire (31) and a disconnection detection wire (33), and a sheath (4) covering the periphery of the braided shield (3). The sheath (4) is provided such that the sheath (4) and the braided shield (3) can move relative to each other in the cable length direction.

Description

Technical Field

[0001] The present invention relates to a cable for a movable part and a life prediction system. Background Art

[0002] Currently, a cable including a break detection line is known. A break detection line is incorporated in its braided shield, and the breakage of the break detection line due to bending, twisting, etc. can be used to predict the breakage time (life) of the cable (for example, refer to Patent Document 1). This cable is configured such that the break detection line breaks due to repeated bending or twisting, external pressure, etc. earlier than the metal wire of the braided shield. In the life prediction system using this cable, by detecting the breakage of the break detection line, it is determined whether the life of the cable with respect to bending, twisting, etc. (hereinafter simply referred to as the life of the cable) is approaching. By determining that the life of the cable is approaching, it is possible to prevent in advance defective conditions such as breakage and short circuit of the cable due to the cable reaching its life.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Laid-Open No. 10-326526 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] When a cable (hereinafter simply referred to as a cable for a movable part) used for wiring of a movable part such as an industrial robot or an automobile uses the above-mentioned existing cable, even if the break detection line arranged in the braided shield breaks due to bending, twisting, etc., the broken part continues to contact without separation, and sometimes the breakage of the break detection line cannot be detected. As a result, it is impossible to correctly determine whether the life of the cable is approaching, and it is sometimes difficult to prevent in advance defective conditions such as breakage and short circuit of the cable.

[0008] Therefore, an object of the present invention is to provide a cable for a movable part including a break detection line and a life prediction system that can be used to accurately predict the life of the cable.

[0009] Means for Solving the Problems

[0010] The present invention aims to solve the above problems and provides a cable for a movable part, including: a cable core wire including a plurality of insulated electric wires; a braided shield provided to cover the periphery of the cable core wire and formed by braiding metal wires and a break detection line; and a sheath covering the periphery of the braided shield, wherein the sheath is provided so that the sheath and the braided shield can move relative to each other in the cable length direction.

[0011] Moreover, the present invention aims to solve the above problems and provides a life prediction system including a cable for a movable part and a detection unit that detects a break in the break detection line.

[0012] Effects of the Invention

[0013] According to the present invention, a cable for a movable part including a break detection line and a life prediction system that can be used to accurately predict the life of the cable can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 FIG. is a diagram showing a cable for a movable part according to an embodiment of the present invention. (a) is a cross-sectional view showing a cross-section perpendicular to the length direction, and (b) is a diagram explaining a braided shield.

[0015] Figure 2 (a) to (c) of FIG. are schematic diagrams showing an example of the positional relationship of a detection wire harness.

[0016] Figure 3 FIG. is a diagram showing a life prediction system according to an embodiment of the present invention. (a) is a schematic configuration diagram, (b) is an equivalent circuit diagram when no break occurs, and (c) is an equivalent circuit diagram when a break occurs.

[0017] Figure 4 FIG. is a cross-sectional view perpendicular to the length direction of a cable for a movable part according to a modification example of the present invention.

[0018] Description of Reference Numerals

[0019] 1 - Cable for movable part, 2 - Cable core wire, 21 - Insulated wire, 3 - Braided shield, 31 - Metal wire, 32 - Wire harness, 33 - Break detection line, 331 - Conductor, 332 - Insulator, 34 - Detection wire harness, 4 - Sheath, 5 - Gap, 10 - Life prediction system, 12 - Detection unit. DETAILED DESCRIPTION OF THE INVENTION

[0020] [Embodiment]

[0021] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0022] Figure 1 FIG. is a diagram showing a cable for a movable part according to the present embodiment. (a) is a cross-sectional view showing a cross-section perpendicular to the length direction, and (b) is a diagram explaining a braided shield.

[0023] As Figure 1As shown in (a) and (b), the cable 1 for the movable part includes a cable core wire 2, a braided shield 3 provided to cover the periphery of the cable core wire 2 as a shielding layer, and a sheath 4 covering the periphery of the braided shield. The cable 1 for the movable part is used for wiring of movable parts such as industrial robots and automobiles, for example.

[0024] (Cable core wire 2)

[0025] The cable core wire 2 includes a plurality of insulated wires 21. In the present embodiment, around the aggregate 22 formed by stranding 4 insulated wires 21 and an intervening member 24, a pressing winding tape 23 is spirally wound to form the cable core wire 2. The insulated wire 21 is constituted by covering a stranded conductor 211 with an insulator 212, wherein the stranded conductor 211 is stranded from a plurality of wire materials made of annealed pure copper, copper alloy, etc. at a predetermined stranding pitch.

[0026] The insulated wire 21 can be a signal line for transmitting signals, a power line for supplying power, or can include both a signal line and a power line. Here, the case where the cable core wire 2 uses 4 insulated wires 21 is shown, but the number of insulated wires 21 used for the cable core wire 2 is not limited to this. And here, the case where all the insulated wires 21 included in the cable core wire 2 have the same outer diameter is shown, but insulated wires 21 with different outer diameters can be included, and components having an outer conductor such as a coaxial line can also be included. As the intervening member 24, for example, a linear body such as rayon can be used. As the pressing winding tape 23, for example, a tape made of Japanese paper, non-woven fabric, or a resin tape can be used.

[0027] (Braided shield 3)

[0028] The braided shield 3 is formed by braiding a metal wire 31 and a break detection wire 33. Figure 1 In (b), in order to distinguish the metal wire 31 and the break detection wire 33, the break detection wire 33 is shown with hatched lines. The metal wire 31 is formed of, for example, a soft copper wire made of pure copper, a copper alloy wire, an aluminum wire made of pure aluminum or aluminum alloy, etc. The metal wire 31 can also be formed of a copper foil wire in which a copper foil is wound around a linear body. The break detection wire 33 is constituted by covering a conductor 331 with an insulator 332. The conductor 331 is constituted by a single-wire conductor such as a soft copper wire or a copper alloy wire. The break detection wire 33 can also be an enameled wire using an enamel coating as the insulator 332. And the break detection wire 33 can also be an extrusion-coated wire in which an insulating resin such as fluororesin is extrusion-coated as the insulator 332.

[0029] The cable 1 for movable parts is configured such that when subjected to repeated bending and twisting, the disconnection detection wire 33 disconnects before the metal wire 31. Specifically, the conductor 331 of the disconnection detection wire 33 preferably has a cross-sectional area larger than that of the metal wire 31, an elongation rate larger than that of the metal wire 31, and a tensile strength smaller than that of the metal wire 31. By using the disconnection detection wire 33 with such a conductor 331, when the cable 1 for movable parts is subjected to repeated bending and twisting, the disconnection detection wire 33 can more easily disconnect before the metal wire 31. Therefore, in the cable 1 for movable parts, the disconnection of the disconnection detection wire can be detected without degrading the shielding performance of the braided shield 3. And for the disconnection detection wire 33, it becomes easier to disconnect if the thickness of the insulator 332 is made thinner. Therefore, the thickness w of the insulator 332 is preferably 15 μm or more and 30 μm or less. By making the thickness w of the insulator 332 15 μm or more, the insulator 332 is less likely to be damaged due to friction during bending and twisting, and by making the thickness w of the insulator 332 30 μm or less, the situation where the disconnection detection wire 33 is difficult to disconnect can be suppressed.

[0030] As Figure 1 shown in (b) of, the braided shield 3 is preferably composed of a plurality of wire bundles 32 formed by arranging a plurality of metal wires 31 side by side in one braid and a plurality of detection wire bundles 34 formed by arranging a plurality of disconnection detection wires 33 side by side in one braid. The "one braid" mentioned here means that the bundle (for example, the wire bundle 32, the detection wire bundle 34) formed by arranging the metal wire 31 and the disconnection detection wire 33 side by side is one, and the "number of braids" mentioned below refers to the total number of the above-mentioned bundles (for example, the wire bundle 32, the detection wire bundle 34) that make up the braided shield. At this time, from the viewpoint of the following wiring operation, the detection wire bundle 34 is preferably composed of one pair or more of the number of braids. For example, in the braided shield 3, when the total number of braids of the wire bundle 32 and the detection wire bundle 34 is 16 braids (the bundles are 16 pieces), the number of braids of the detection wire bundle 34 among them can be 2 braids (one pair), 4 braids (two pairs), 6 braids (three pairs), etc.

[0031] The braided shield 3 is formed by braiding the above-described plurality of wire bundles 32 and the plurality of detection wire bundles 34. Compared with the case of a bundle in which the broken wire detection line 33 and the metal wire 31 are mixed, the operation of connecting the ends of the broken wire detection lines 33 becomes easier. For example, when the broken wire detection line 33 and the metal wire 31 are mixed in a bundle, operations such as untying are required to distinguish the broken wire detection line 33 and the metal wire 31 arranged at the ends within the bundle. In contrast, in the case where the braided shield 3 is formed by braiding a plurality of wire bundles 32 each formed by arranging a plurality of metal wires 31 in parallel and a plurality of detection wire bundles 34 each formed by arranging a plurality of broken wire detection lines 33 in parallel, by taking out the ends of the detection wire bundles 34 of a bundle from the braided shield 3 and connecting the ends of the detection wire bundles 34 to each other, the ends of the broken wire detection lines 33 can be connected to each other. Therefore, the efficiency of the wiring operation for connecting the ends of the broken wire detection lines 33 can be improved. And, in Figure 1 In the braided shield 3 shown in (b) of Figure 1 , compared with the case where the broken wire detection line 33 and the metal wire 31 are mixed in a bundle, it is possible to suppress the shielding performance from being reduced due to the operation of untying the ends of the braided shield 3. And, in Figure 1 In the braided shield 3 shown in (b) of

[0032] , at a portion other than the end of the movable part cable 1 (for example, any part in the cable length direction), the detection wire bundle 34 can be taken out to the outside of the sheath 4 in a state branched from the wire bundle 32 and connected to the following arithmetic unit 11 and the like. In the present embodiment, the braided shield 3 is formed by braiding a plurality of wire bundles 32 and a pair of detection wire bundles 34 formed by two bundles. The number of metal wires 31 and broken wire detection lines 33 (strands) constituting one bundle of wire bundles 32 and one bundle of detection wire bundles 34 is not particularly limited. Here, as an example, the case where the number of strands in one bundle is 5 will be described.

[0032] The braided shield 3 is formed by braiding wire bundles 32 inclined at a predetermined angle (for example, about 30 degrees to 40 degrees) with respect to the length direction of the movable part cable 1, wire bundles 32 inclined at a predetermined angle in the opposite direction with respect to the length direction, and the detection wire bundles 34. In Figure 1 In the present embodiment shown in (b) of

[0033] , the inclination directions of the two detection wire bundles 34 are set to the same direction. In addition, from the viewpoint of not deteriorating the shielding performance of the braided shield 3 and correctly detecting the breakage of the broken wire detection line, when braiding the wire bundles 32 and the detection wire bundles 34, it is preferably braided at a pitch larger than the stranding pitch of the stranded conductor 211 constituting the insulated wire 21 or the stranding pitch of the plurality of insulated wires 21 constituting the cable core wire 2.

[0033] And, in the present embodiment, as Figure 2As shown in (a) thereof, in a cross-section perpendicular to the longitudinal direction of the cable 1 for the movable part, the detection wire bundles 34 are arranged such that the circumferential positions of the two detection wire bundles 34 are approximately 90 degrees with respect to the center of the cable. However, it is not limited thereto. For example, as shown in Figure 2 (b) thereof, the two detection wire bundles 34 are opposed to each other in the radial direction with the cable core wire 2 interposed therebetween. By arranging the two detection wire bundles 34 in close proximity, the multiple break detection lines 33 break approximately simultaneously, enabling immediate detection of cable deterioration. Therefore, especially when using the cable 1 for the movable part in applications where safety improvement is desired, the arrangement shown in Figure 2 (a) or an arrangement in which the two detection wire bundles 34 are set closer can be adopted. Also, when the outer diameter of the cable 1 for the movable part is large and the number of wire bundles 32 used (i.e., the number of bundles) is large, it is also considered that the break detection line 33 is difficult to break depending on the bending position and bending direction. In this case, it is preferable to separately arrange the detection wire bundles 34 as shown in Figure 2 (b) thereof.

[0034] Also, in the present embodiment, the inclination directions of the two detection wire bundles 34 are set to the same direction, but as shown in Figure 2 (c) thereof, the inclination directions of the two detection wire bundles 34 can be set to different directions. In this case, the two detection wire bundles 34 cross periodically in the longitudinal direction of the cable 1 for the movable part, and at the crossing position, the two detection wire bundles 34 are arranged overlappingly in the radial direction.

[0035] In addition, in the present embodiment, the case of using a pair of detection wire bundles 34 has been described, but for example, two or more pairs of detection wire bundles 34 with a number of bundles can also be used. Among them, as described in the present embodiment, by using a pair of detection wire bundles 34, even when the number of bundles is small, the number of wire bundles 32 used can be ensured, and deterioration of the shielding performance can be suppressed. Also, by using a pair of detection wire bundles 34, the number of break detection lines 33 used can be reduced and the wiring operation can be facilitated. Furthermore, by reducing the number of break detection lines 33 used, the change in the resistance value caused by the break of one break detection line 33 becomes larger, and a decrease in the sensitivity for predicting the life of the cable 1 for the movable part can be suppressed.

[0036] It is also possible that the break detection lines 33 are dyed different colors in each detection wire bundle 34. Thereby, when constructing the following life prediction system 10, it becomes easy to distinguish which break detection line 33 belongs to which detection wire bundle 34, and thus the wiring operation becomes easy.

[0037] (Sheath 4)

[0038] The sheath 4 is made of an insulating resin such as polyvinyl chloride resin and covers the periphery of the braided shield 3. In the movable part cable 1 of the present embodiment, the sheath 4 is arranged such that in a state where the movable part cable 1 is linearly arranged, the sheath 4 and the braided shield 3 can move relative to each other in the length direction. The sheath 4 is formed, for example, by pipe extrusion and is formed loosely so as not to apply a force that presses the braided shield 3 radially inward as much as possible. Also, the sheath 4 is arranged not to enter the meshes of the braided shield 3 (the gaps formed between the wire bundles 32 and the detection wire bundles 34). Here, "the sheath 4 and the braided shield 3 can move relative to each other in the length direction" means that in a state where the movable part cable 1 is linear, after pulling out the end of the braided shield 3 from the end of the sheath 4 in the cable length direction, the braided shield 3 can be pulled out from the sheath 4 (the braided shield 3 can move independently of the sheath 4). In addition, when the braided shield 3 is pulled out from the sheath 4, the cable core wire 2 can also move together with the braided shield 3.

[0039] For example, in a case where the braided shield 3 is firmly pressed radially inward by the sheath 4, in a state where the movable part cable 1 is bent or twisted, the metal wires 31 and the disconnection detection wires 33 are fixed by the sheath 4 and are difficult to move. Therefore, even after the disconnection detection wire 33 is disconnected due to repeated bending or twisting of the movable part cable 1, there is a concern that the disconnected part will be held by the sheath 4 and continue to make contact. And, in this case, when the movable part cable 1 is repeatedly bent or twisted, the disconnection detection wires 33 rub against each other, the metal wires 31 rub against each other, or the disconnection detection wire 33 rubs against the metal wire 31 while being pressed against the cable core wire 2 side, and thus are likely to be disconnected. Therefore, there is also a concern that the life of the movable part cable 1 will be reduced and the life of the movable part cable 1 cannot be predicted correctly. As described in the present embodiment, by enabling the sheath 4 and the braided shield 3 to move relative to each other in the length direction, when the movable part cable 1 is repeatedly bent or twisted, the above-mentioned adverse conditions can be suppressed, and when the disconnection detection wire 33 is disconnected, the disconnected part is easily separated. Thereby, it is possible to prevent the situation where the disconnected part of the disconnection detection wire 33 continues to make contact and the disconnection cannot be detected, and the life (deterioration) of the movable part cable 1 bent or twisted can be predicted correctly. And, when the movable part cable 1 is repeatedly bent or twisted, it is possible to suppress the disconnection of the disconnection detection wire 33 due to the rubbing of the disconnection detection wires 33 against each other and the rubbing of the disconnection detection wire 33 and the metal wire 31 against each other. Therefore, it is possible to suppress the reduction of the life of the movable part cable 1 and to predict the life of the movable part cable 1 correctly.

[0040] In order to make the part after the disconnection easier to separate when the disconnection detection line 33 is disconnected, the cable 1 for the movable part is more preferably in a state of being linearly arranged, and at least a part in the circumferential direction, the sheath 4 and the braided shield 3 are separated in the radial direction, so that there is a gap 5 between the sheath 4 and the braided shield 3. By having the gap 5 between the sheath 4 and the braided shield 3 in the cable 1 for the movable part, it is easy to relatively move the sheath 4 and the braided shield 3 in the cable length direction. Therefore, it is easy to obtain the above-mentioned functions and effects. The width of the gap 5 (the maximum value of the radial interval between the sheath 4 and the braided shield 3) d is preferably set to 0.2 mm or less (0 mm < d ≤ 0.2 mm). By making the width d of the gap 5 0.2 mm or less, it is possible to suppress the case where the cable core wire 2 and the braided shield 3 fly out of the sheath 4 during terminal processing and the terminal processability deteriorates, and it is also possible to suppress the case where the gap 5 becomes too large and the sheath 4 buckles. In addition, for the width of the gap 5, for example, by observing the cross-section (cross-sectional view) perpendicular to the length direction of the cable 1 for the movable part using an optical microscope or an electron microscope, the maximum value of the radial interval between the sheath 4 and the braided shield 3 can be calculated as the width of the gap 5 from the cross-sectional photograph obtained by the observation.

[0041] (Lifetime prediction system)

[0042] Figure 3 FIG. is a diagram showing the lifetime prediction system of the present embodiment, (a) is a schematic configuration diagram, (b) is an equivalent circuit diagram when no disconnection occurs, and (c) is an equivalent circuit diagram when a disconnection occurs.

[0043] As Figure 3 shown in (a) of, the lifetime prediction system 10 includes the cable 1 for the movable part of the present embodiment and an arithmetic device 11 having a detection unit 12 that detects the disconnection of the disconnection detection line 33 of the cable 1 for the movable part.

[0044] In the lifetime prediction system 10, for a pair of detection wire bundles 34 of the cable 1 for the movable part, at both ends thereof, the ends of the disconnection detection line 33 constituting the detection wire bundle 34 (the ends of the conductor 331) are electrically connected respectively, and one end of one detection wire bundle 34 ( Figure 3 the left end in (a) of) and one end of the other detection wire bundle 34 ( Figure 3 the left end in (a) of) are electrically connected. The other ends of the two detection wire bundles 34 ( Figure 3 the right end in (a) of) are connected to the arithmetic device 11.

[0045] The arithmetic unit 11 is, for example, a microcomputer, and the detection unit 12 is implemented by appropriately combining a CPU, a memory, an interface, software, and the like. The detection unit 12 detects the disconnection of the disconnection detection line 33 based on the change in the conductor resistance between the other ends of the two detection wire bundles 34. Specifically, the detection unit 12 constantly measures the conductor resistance by applying a voltage between the other ends of the two detection wire bundles 34 and measuring the current flowing at this time. Moreover, based on the change in the conductor resistance constantly measured, it is detected that the disconnection detection wire bundle 34 has been disconnected.

[0046] For example, when the number of strands is set to 5 and the conductor resistance of one disconnection detection line is set to R, as shown in Figure 3 (b) of, in a state where the disconnection detection line 33 has not been disconnected, the conductor resistance measured by the detection unit 12 is (2 / 5)R = 0.4R. Here, if it is assumed that one disconnection detection line 33 is disconnected in each of the two detection wire bundles 34, as shown in Figure 3 (c) of, the conductor resistance measured by the detection unit 12 is (2 / 4)R = 0.5R, and the conductor resistance increases by 25% relative to the initial value (0.4R). Therefore, by measuring the conductor resistance between the other ends of the two detection wire bundles 34, it is possible to infer how many disconnection detection lines 33 are disconnected based on the measured value of the conductor resistance.

[0047] In the present embodiment, a life determination unit 13 and an alarm unit 14 are mounted on the arithmetic unit 11. The life determination unit 13 determines the period when the life of the cable 1 for the movable part is reached based on the value of the conductor resistance measured by the detection unit 12, and the alarm unit 14 generates an alarm according to the determination of the life determination unit 13. The life determination unit 13 and the alarm unit 14 are implemented by appropriately combining a CPU, a memory, an interface, software, and the like.

[0048] The life determination unit 13 has a database storing the relationship between the value of the conductor resistance or the increase ratio of the value of the conductor resistance and the life of the cable 1 for the movable part. When the conductor resistance measured by the detection unit 12 increases by a predetermined ratio relative to the initial value (for example, when the conductor resistance increases by 10% compared to the initial value), the life determination unit 13 determines based on the above database that the cable 1 for the movable part reaches the life at a predetermined period. In addition, the life determination unit 13 may also determine the period when the life of the cable 1 for the movable part is reached in stages. For example, it may be determined in stages when the conductor resistance increases by 5% compared to the initial value, by 10% compared to the initial value, and by 20% compared to the initial value. In addition, the arithmetic unit 11 may also have the following function: based on the data actually obtained by the detection unit 12, update the relationship between the value of the conductor resistance, the increase ratio of the value of the conductor resistance, and the life of the cable 1 for the movable part stored in the above database.

[0049] When the life determination unit 13 determines that the cable 1 for the movable part has reached the predetermined life, the alarm unit 14 issues an alarm to prompt the replacement of the cable 1 for the movable part. For example, the alarm unit 14 can also drive an alarm device 15 that issues an alarm through light or sound to issue an alarm. In addition, the alarm unit 14 can issue an alarm to the manager by email or the like, or can issue an alarm by displaying a message on the management display or the like.

[0050] (Functions and Effects of the Embodiment)

[0051] As described above, in the cable 1 for the movable part of the present embodiment, the braided shield 3 formed by the braided metal wire 31 and the disconnection detection wire 33 is provided, and the sheath 4 covering the periphery of the braided shield 3 is provided such that the sheath 4 and the braided shield 3 can move relative to each other in the length direction.

[0052] With such a configuration, even if the disconnection detection wire 33 is disconnected, it is possible to suppress the disconnection part from being held by the sheath 4 and prevent problems such as contact retention, so that the life of the cable 1 for the movable part can be predicted with high accuracy. In addition, it is possible to suppress the disconnection of the disconnection detection wire 33 and the metal wire 31 caused by friction, and to suppress the reduction of the life of the cable 1 for the movable part.

[0053] (Modification Example)

[0054] As Figure 4 shown in the cable 1a for the movable part, the cable core 2 may also include a twisted pair 25 formed by twisting a pair of insulated wires 21. In the cable 1a for the movable part, the following is shown: around the aggregate 22 formed by twisting 4 twisted pairs 25 together with the intervening member 24, a pressing winding band 23 is spirally wound to form the cable core 2. In addition, the cable core 2 may also include both the twisted pair 25 and the insulated wire 21 that is not the twisted pair 25 (for example, a power line).

[0055] (Summary of the Embodiment)

[0056] Next, the technical idea grasped from the above-described embodiment will be described by referring to the symbols in the embodiment. Among them, the symbols and the like in the following description do not limit the components in the claims to the components specifically shown in the embodiment.

[0057] [1] A cable 1 for a movable part, comprising: a cable core 2 including a plurality of insulated wires 21; a braided shield 3 provided to cover the periphery of the cable core 2 and formed by a braided metal wire 31 and a disconnection detection wire 33; and a sheath 4 covering the periphery of the braided shield 3, the sheath 4 being provided such that the sheath 4 and the braided shield 3 can move relative to each other in the cable length direction.

[0058] [2] For the cable 1 for a movable part described in [1], in at least a part of the circumferential direction, the sheath 4 and the braided shield 3 are separated in the radial direction.

[0059] [3] For the cable 1 for a movable part described in [1] or [2], the braided shield 3 is formed by braiding a wire bundle 32 composed of a plurality of the metal wires 31 and a detection wire bundle 34 composed of a plurality of the break detection wires 33, and the detection wire bundle 34 is composed of one or more pairs of strands.

[0060] [4] For the cable 1 for a movable part described in [3], the detection wire bundle 34 of the braided shield 3 is composed of a pair.

[0061] [5] For the cable 1 for a movable part described in any one of [1] to [4], the break detection wire 33 is configured such that an insulator 332 is coated around a conductor 331, the cross-sectional area of the conductor 331 is larger than the cross-sectional area of the metal wire 31, the elongation rate is larger than the elongation rate of the metal wire 31, and the tensile strength is smaller than the tensile strength of the metal wire 31.

[0062] [6] A life prediction system 10 includes: the cable 1 for a movable part described in any one of [1] to [5]; and a detection unit 12 that detects a break in the break detection wire 3.

[0063] [7] For the life prediction system 10 described in [6], the braided shield 3 is formed by braiding a wire bundle 32 composed of a plurality of the metal wires 31 and a detection wire bundle 34 composed of a plurality of the break detection wires 33, the detection wire bundle 34 is composed of a pair, at both ends thereof, the end portions of the break detection wires 3 constituting the detection wire bundle 34 are electrically connected respectively, and one end portion of one detection wire bundle 34 is electrically connected to one end portion of the other detection wire bundle 34, and the detection unit 21 detects a break in the break detection wire 33 based on the conductor resistance between the other end portions of the pair of detection wire bundles 34.

[0064] The embodiments of the present invention have been described above, but the embodiments described above do not limit the invention of the claims. And it should be noted that all combinations of features described in the embodiments are not necessarily limited to the solutions necessary for solving the problems of the invention. Furthermore, the present invention can be appropriately modified and implemented without departing from its gist.

Claims

1. A cable for a movable part, characterized in that, Comprising: A cable core wire, which includes a plurality of insulated wires; A braided shield, which is arranged to cover the periphery of the above-mentioned cable core wire, and is formed by braiding the above-mentioned metal wire and the above-mentioned break detection wire in such a way that no metal wire and break detection wire are mixed in one strand; and A sheath, which covers the periphery of the above-mentioned braided shield, The above-mentioned sheath is arranged such that the sheath and the above-mentioned braided shield can move relative to each other in the cable length direction.

2. The cable for a movable part according to claim 1, characterized in that In at least a part of the circumferential direction, the above-mentioned sheath and the above-mentioned braided shield are separated in the radial direction.

3. The cable for a movable part according to claim 1, characterized in that The above-mentioned braided shield is composed of a bundle of braided wires and a bundle of detection wires. One strand of wire bundle is composed of a plurality of the above-mentioned metal wires arranged in parallel, and one strand of detection wire bundle is composed of a plurality of the above-mentioned break detection wires arranged in parallel. The above-mentioned detection wire bundle is composed of more than one pair of strands.

4. The cable for a movable part according to claim 3, characterized in that The above-mentioned detection wire bundle of the above-mentioned braided shield is composed of a pair.

5. The cable for a movable part according to any one of claims 1 to 4, characterized in that The above-mentioned break detection wire is configured to have an insulator covering the periphery of a conductor, The cross-sectional area of the above-mentioned conductor is larger than the cross-sectional area of the above-mentioned metal wire, the elongation rate is larger than the elongation rate of the above-mentioned metal wire, and the tensile strength is smaller than the tensile strength of the above-mentioned metal wire.

6. A life prediction system, characterized in that, Comprising: The cable for a movable part according to any one of claims 1 to 5; and A detection part for detecting a break in the above-mentioned break detection wire.

7. The life prediction system according to claim 6, characterized in that The above-mentioned braided shield is composed of a bundle of braided wires and a bundle of detection wires. One strand of wire bundle is composed of a plurality of the above-mentioned metal wires arranged in parallel, and one strand of detection wire bundle is composed of a plurality of the above-mentioned break detection wires arranged in parallel, The above-mentioned detection wire bundle is composed of a pair, and at both ends thereof, the ends of the above-mentioned break detection wires constituting the detection wire bundle are electrically connected respectively, and one end of one detection wire bundle is electrically connected to one end of the other detection wire bundle, The above-mentioned detection part detects a break in the above-mentioned break detection wire based on the conductor resistance between the other ends of the above-mentioned pair of detection wire bundles.

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