Cable assembly

Abstract

To provide a cable assembly that includes a cable used for an arm and the like of an industrial robot, and that is durable against a repetitive complicated movement of the arm, and can suppress dust emission to prevent an adverse influence on the circumference.SOLUTION: There is provided a cable assembly provided with a connection part having a protective part and a fitting part at the sheath of a cable. The fitting part enables the cable assembly to be fitted to a connection target body, and the protective part covers the sheath. The protective part has a structure decreasing in rigidity from a proximal end side to a distal end side, and the rigidity of the distal side is 3 to 10% of that of the proximal end side.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cable that is suitable for use in an industrial robot. [Background technology]

[0002] Industrial robots, such as articulated robots, have arms that perform complex movements repeatedly. Some industrial robots have cables routed outside the arms to avoid hindering the complex movements of the arms and to prevent the cables from breaking due to the complex movements of the arms.

[0003] When a cable is routed outside the arm, both ends of the cable are fixed, but the middle part of the cable is floating and not fixed, so when the arm moves, the middle part of the cable will vibrate and bend.

[0004] When wiring cables outside the arm of the above-mentioned industrial robot, a common structure is to provide a cable gland on the wall of the robot and fix the cables by the cable gland.

[0005] Therefore, a cable assembly is used which has a structure in which a part having a function of attaching and fixing the cable to the industrial robot is combined with the cable.

[0006] For example, Patent Document 1 describes a structure in which a grommet is integrally molded on a bundle of electric wires or the like.

[0007] Furthermore, Patent Document 2 describes a structure in which the main body of the grommet is fused and fixed to the cable, and the guide portion is brought into close contact with the cable.

[0008] However, although the invention described in Patent Document 1 is expected to prevent damage caused by contact with the edge of the through-hole using grommets, it is not designed for use in an environment where vibrations and bending are repeated, and issues remain regarding bending resistance.

[0009] In the invention described in Patent Document 2, the cable is protected by providing a guide portion in the grommet, but the guide portion and the cable are not fixed, and repeated bending causes friction between the guide portion and the cable, generating dust, which may have a negative impact on the surrounding area. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Publication No. 1-111417 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-183498 Summary of the Invention [Problem to be solved by the invention]

[0011] An object of the present invention is to provide a cable assembly for a cable used in the arm of an industrial robot that repeats complex movements, which has high durability against vibration and bending of the cable caused by arm movement, and which suppresses dust generation due to friction between the cable and parts for fixing and connecting the cable. [Means for solving the problem]

[0012] The inventors have reviewed the connection structure between cables and connected objects, such as industrial robots and the arms of industrial robots, and have found that the above-mentioned problems can be solved by adopting the following structure.

[0013] (1) A cable assembly having a cable with a sheath that covers a conductor or one or more electric wires, and a connection part provided on the sheath, wherein the connection part has an attachment part that enables the cable assembly to be attached to an object to be attached, and a protective part that covers the sheath. (2) The cable assembly according to (1) above, wherein the mounting portion and the protection portion are integrally molded. (3) The cable assembly according to (1) above, wherein the mounting portion is a separate mounting portion that is separate from the protection portion. (4) The cable assembly according to (3) above, wherein the protective portion is capable of accommodating at least a part of the separate mounting portion. (5) The cable assembly according to any one of (1) to (4) above, wherein the rigidity of the protective portion decreases from the base end side to the tip end side. (6) The cable assembly according to any one of (1) to (5) above, wherein the rigidity of the tip end side of the protective part is 3 to 10% of the rigidity of the base end side of the protective part. (7) The cable assembly according to any one of (1) to (6) above, wherein the cross-sectional area of ​​the face perpendicular to the longitudinal direction of the protection part decreases from the base end side to the tip end side. (8) The cable assembly according to any one of (1) to (7) above, wherein the cross-sectional area of ​​the tip end side of the protection part is 3 to 10% of the cross-sectional area of ​​the base end side of the protection part. (9) The cable assembly according to any one of (1) to (8) above, wherein the rigidity of the tip end side of the protective part is 10 to 25% of the rigidity of the cable. (10) The cable assembly according to any one of (1) to (9) above, wherein a convex structure is provided on the bottom surface of the protection part.

[0014] Furthermore, configurations in which the configurations described in (1) to (10) above are appropriately selected and combined also fall within the technical scope of the present disclosure. [Effects of the Invention]

[0015] The cable assembly of the present invention reduces the load on the cable by reducing the vibration and bending of the cable caused by the complex movements of the arm of the industrial robot, improving its durability and preventing dust generation, so it can be suitably used as a cable for industrial robots without being adversely affected by dust generated in the surrounding area. [Brief explanation of the drawings]

[0016] [Figure 1]1 shows the basic structure of a cable assembly according to the present invention. [Figure 2] 1 is an example of a cross-sectional structure of a cable used in the present invention. [Figure 3] 10 is an example of the structure of the mounting portion. [Figure 4] This is an example of a protective portion having a convex structure on the bottom surface. [Figure 5] This is an embodiment of the present invention. [Figure 6] This is a twisting and bending tester for evaluating the magnitude of runout. [Figure 7] 1 shows the state of a twisting and bending test of an example and a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0017] A cable assembly 1 of the present invention will be described below with reference to the drawings.

[0018] FIG. 1 shows the basic structure of a cable assembly 1 of the present invention, which is composed of a cable 10 and a connection part 20 provided on a sheath 11 of the cable 10.

[0019] An example of a cable 10 used in the cable assembly 1 is a multi-core cable consisting of an assembly made up of an electric wire unit 13 made up of multiple electric wires 12 and multiple tubes 14, as shown in Figure 2, and a sheath 11 that covers the assembly as a whole.

[0020] When used in a device having a pneumatic or hydraulic drive unit, the tube 14 is suitably used as a path for air, oil, or the like.

[0021] The material of the tube 14 used in the cable 10 may be adjusted as appropriate to suit the substance that will pass through the inside of the tube 14. For example, if air passes through the inside of the tube 14, nylon or polyurethane, which have high airtightness, is suitable, and if oil will pass through, fluororesin, which has high oil resistance, is a generally suitable material.

[0022] The example configuration of cable 10 shown in Figure 2 shows a multi-core cable that combines multiple electric wires 12 and multiple tubes 14, but the cable 10 used in the present invention is not limited to a combination of electric wires 12 and tubes 14, and may be a multi-core cable composed only of multiple electric wires 12, an insulated electric wire with an insulating layer on the conductor, a coaxial cable that also has an outer conductor and an outer sheath, an optical fiber cable, or other single wire.

[0023] The electric wire unit 13 may be a twisted pair wire, a two-core parallel coaxial cable, or the like, and a plurality of twisted pair wires may be twisted together to form the electric wire unit 13. The electric wire unit 13 may also include an optical fiber cable.

[0024] The optical fiber cable may be included in the electric wire unit 13, or may be twisted with the electric wire unit 13 and the tube 14 to form the cable 10.

[0025] The core material and coating material of each electric wire 12 used in the cable 10 may be adjusted as appropriate depending on the application. In addition, the materials and configurations of the dielectric and outer conductor that make up the coaxial cable or the like may also be adjusted as appropriate depending on the application.

[0026] When the cable 10 is configured with a single wire, the sheath 11 of the cable 10 corresponds to the outermost layer of the single wire.

[0027] The material of the sheath 11 used in the cable 10 is preferably a material that has fusion or adhesive properties with the protective portion 30 described below.

[0028] In addition, it is preferable that the cable 10 is lightweight yet has a certain degree of rigidity so as not to hinder the complex movements that are repeated when the arm of the industrial robot is operating, and in consideration of the resistance to the vibration and bending of the cable 10 caused by the complex movements that are repeated.

[0029] Therefore, the material of the sheath 11 used in the cable 10 is preferably polyurethane, silicone rubber, polyvinyl chloride (PVC), or the like, which has good adhesiveness and fusion properties, is lightweight yet rigid, and is less likely to generate dust.

[0030] The cable assembly 1 has at least one connection part 20 provided on the sheath 11 of the cable 10, and the connection part 20 includes a protective part 30 and an attachment part 40. A plurality of connection parts 20 may be provided depending on the application.

[0031] The mounting portion 40 has a structure that allows it to be mounted on the wall of a connected body to which the cable assembly 1 is to be attached.

[0032] The protective portion 30 has a shape that covers the sheath 11 from the base end side of the connecting portion 20 where the attachment portion 40 is provided to the tip side of the connecting portion 20 on the opposite side from the base end side.

[0033] The protective portion 30 preferably has a structure in which the rigidity decreases from the base end side to the tip end side.

[0034] The reduction in rigidity can be selected from a structure in which the rigidity decreases continuously or in stages, or a combination of continuous and staged reductions. The specific state of reduction in rigidity may be any change from the base end to the tip end within a range in which the stress dispersion effect of the protective portion 30 described below can be obtained, and may be adjusted depending on the application and structure.

[0035] The protective part 30 has a structure in which the rigidity decreases from the base end side to the tip end side, so that flexibility is imparted to the tip end side while deformation on the base end side is suppressed.

[0036] At the tip end side of the protective part 30, the cable 10 can bend in response to the movement of the connected object, while at the base end side of the protective part 30, the cable 10 is prevented from swaying or bending in response to the movement of the connected object. Therefore, while the entire cable 10 is allowed to bend in response to the movement of the connected object, unnecessary bending is prevented near the protective part 30, which prevents the cable 10 from swaying and contributes to improving the durability of the cable 10.

[0037] In addition, stress caused by vibration or bending of the cable 10 due to movement of the connected object is dispersed within the protective portion 30, which contributes to improving the durability of the cable 10.

[0038] One example of a structure in which the rigidity of the protective part 30 decreases from the base end to the tip end is to reduce the cross-sectional area of ​​the plane perpendicular to the longitudinal direction of the protective part 30 from the base end to the tip end. In addition to adjusting the cross-sectional area of ​​the protective part 30 to adjust the hardness, methods such as providing a distribution in the rigidity of the material constituting the protective part 30 or combining multiple materials with different rigidities may also be used to change the rigidity. It is also possible to combine adjusting the cross-sectional area and adjusting the material. The cross-sectional shape may be circular, polygonal, or a shape combining curved and flat surfaces. Alternatively, the rigidity may be reduced by providing grooves, lightening holes, or the like.

[0039] From the viewpoint of dispersing stress due to vibration or bending within the protective part 30, the rigidity of the distal end side of the protective part 30 is preferably 3 to 10% of the rigidity of the proximal end side. When reducing the rigidity by adjusting the cross-sectional area, the cross-sectional area of ​​the distal end side of the protective part 30 is preferably 3 to 10% of the cross-sectional area of ​​the proximal end side of the protective part 30.

[0040] From the viewpoint of further promoting the dispersion of stress due to vibration or bending inside the protective part 30, it is advisable to consider not only the change in rigidity but also the length from the base end to the tip end of the protective part 30. Specifically, it is preferable that the length of the protective part 30 be equal to or greater than the outer diameter of the cable 10, but the length is not limited to this and may be adjusted as appropriate depending on the purpose and application.

[0041] Furthermore, in the present invention, the rigidity of the tip end side of the protective part 30 is preferably 10 to 25% of the rigidity of the cable 10. By setting the rigidity of the tip end side of the protective part 30 in this manner, the difference between the rigidity at the tip end of the protective part 30 and the rigidity of the cable 10 protruding from the tip end of the protective part 30 near the tip of the protective part 30 becomes smaller, the load on the cable 10 near the tip end of the protective part 30 is alleviated, and the bending resistance of the cable 10 can be improved.

[0042] 3(a) is an example of the structure of the mounting part 40 that enables attachment to the wall of the connected body. The structure shown in Fig. 3(a) includes a male screw 41 and a nut 42. In the structure including the male screw 41 and the nut 42, the male screw 41 can be inserted into a mounting hole provided in the wall of the connected body, and the nut 42 can be tightened to fix the connected body.

[0043] Another example of the structure of the mounting part 40 is the structure shown in Fig. 3(b). The mounting part 40 shown in Fig. 3(b) has an insertion end 43 whose outer diameter is smaller than the mounting hole provided in the wall of the connected body, a support part 45 whose outer diameter is larger than the mounting hole, and a sliding part 44 whose outer diameter gradually increases from the insertion end 43 to the support part 45, and a groove part 46 is provided between the support part 45 and the protective part 30.

[0044] The mounting part 40 shown in FIG. 3(b) is fixed to the connected body by inserting the mounting end 43 into the mounting hole and engaging the groove 46 with the periphery of the mounting hole provided in the wall body.

[0045] If the mounting hole is not circular, for example, if it has a hole shape intended to prevent rotation, such as a D-hole, the cross-sectional shape of groove portion 46 can be modified to a shape that can fit into the shape of the mounting hole.

[0046] In addition to the above, commercially available joint parts configured to hold the cable 10 (for example, the highly waterproof AG series cable gland manufactured by Takachi Electric Industrial Co., Ltd., the waterproof cable clamp "Capcom" product manufactured by Ohm Electric Co., Ltd., the Super Grand product manufactured by Nippon AVC Inc., the K-Grand product manufactured by Sankei Manufacturing Co., Ltd., etc.) can also be used as the mounting part 40.

[0047] The structure of the connected body to which the mounting part 40 having the groove 46 is fixed can be the structure in which a mounting hole is provided in the wall as described above, but it is also possible to use a structure in which two wall plates each have a semicircular part that can be engaged with the groove 46, and the semicircular parts sandwich and engage the groove 46 to fix the mounting part 40. In this structure, the loading end 43 and the sliding part 44 may be omitted.

[0048] 4, an elastically deformable convex structure 31 may be provided on the bottom surface of the protective part 30. The presence of the elastically deformable convex structure 31 allows the convex structure 31 to press against the wall of the connected body when the bottom surface of the protective part 30 is brought into contact with the wall, thereby preventing moisture, dust, etc. from penetrating into the connected body through the mounting hole.

[0049] From the viewpoint of preventing moisture, dust, and the like from penetrating into the connected object, it is preferable that the convex structure 31 is provided in the radial direction so as to surround the entire circumference of the insertion hole of the cable 10, as shown in Fig. 4. The convex structure 31 may have a shape other than the circle shown in Fig. 4, as long as it surrounds the entire circumference of the insertion hole of the cable 10.

[0050] The following is a method for providing the connection portion 20 on the sheath 11 of the cable 10 to form the cable assembly 1.

[0051] One method is a molding method in which the cable 10 is set in a mold and the protective portion 30 and the attachment portion 40 are integrally molded onto the sheath 11.

[0052] In this method, the protective portion 30 and the mounting portion 40 can be integrated, which reduces the number of parts, resulting in cost reduction and improved workability.

[0053] Another method is to make the attachment part 40 and the protection part 30 separate.

[0054] When the protective part 30 and the attachment part 40 are separate bodies, the method of providing the protective part 30 on the sheath 11 can be selected from "(A) a method of providing the protective part 30 on the sheath 11 by molding" and "(B) a method of fixing a pre-molded protective part 30 on the sheath 11."

[0055] An example of "(A) a method of providing a protective part 30 by molding" is "(A-1) a method of using a separate mounting part 40 (separate mounting part 48) that has a cable insertion hole, inserting the cable 10 into the separate mounting part 48, and then molding the protective part 30 so that it covers a part of the tip side of the separate mounting part 48."

[0056] Since the protective part 30 is molded including a part of the separate mounting part 48 , the protective part 30 is provided on the sheath 11 and the separate mounting part 48 is fixed to the protective part 30 at the same time.

[0057] Because the separate mounting part 48 is fixed to the protective part 30 during molding, it is not necessarily necessary to fix the separate mounting part 48 to the cable 10. When fixing the separate mounting part 48 to the cable 10, an appropriate fixing method can be selected from adhesive bonding, fusion bonding, and the like.

[0058] The separate mounting portion 48 can be made of a high-hardness resin or metal part, and can be suitably used when providing the male screw 41.

[0059] Furthermore, as the separate mounting portion 48, a member having a cable fixing function, such as the above-mentioned commercially available cable clamp, can also be used.

[0060] Another example of "(A) a method of providing a protective part 30 by molding" is "(A-2) a method of molding a protective part 30 onto a sheath 11, and then inserting the cable 10 into a separate mounting part 48 and fixing the separate mounting part 48 and the protective part 30 together."

[0061] At this time, methods for fixing the separate mounting part 48 and the protective part 30 include adhesive fixing, press-fit fixing, fitting fixing, etc. When using these fixing methods, it is preferable to mold the protective part 30 so that it can accommodate at least a part of the separate mounting part 48.

[0062] In this method (A-2), the separate mounting portion 48 can be the same as that used in the above-mentioned method (A-1).

[0063] In the case of "(B) Method of fixing a pre-molded protective part 30 onto the sheath 11," the protective part 30 having a cable insertion hole is molded in advance, the cable 10 is inserted into the protective part 30, and then the cable 10 is fixed to the sheath 11 by adhesion, fusion, etc.

[0064] In the case of this method (B), the separate mounting portion 48 can be provided in a manner similar to the above-mentioned method (A-2), and the separate mounting portion 48 can be inserted into the cable 10 before or after inserting or fixing the protective portion 30, and if necessary, the protective portion 30 can be molded so as to accommodate at least a portion of the separate mounting portion 48. <Example>

[0065] Example 1 A first embodiment of the present invention will be described with reference to FIGS. 5(a) to 5(c).

[0066] The cable 10 shown in Figure 2 was inserted into a commercially available cable gland (waterproof cable clamp "OA-W2823E" manufactured by Ohm Electric Co., Ltd.) prepared as a separate mounting part 48, and fixed onto the sheath 11 to form the state shown in Figure 5(a).

[0067] The protective portion 30 was produced by injection molding, having a cable insertion hole and a housing portion for the separate mounting portion 48 as shown in FIG. 5(b).

[0068] The cable 10 was inserted into the prepared protective portion 30, the tip of the cable gland was housed in the protective portion 30, and the sheath 11 and the protective portion 30, and the cable gland and the protective portion 30 were bonded together with a silicone-based adhesive, thereby obtaining the cable assembly 1 of the present invention shown in Figure 5(c).

[0069] The material of the sheath 11 of the cable 10 was PVC, and the outer diameter was 22.3 mm.

[0070] The material of the protective part 30 is chloroprene with a hardness of 45 degrees, and the outer diameter at the base end is 70 mm, tapering to 27 mm at the tip end. The length of the protective part 30 is 100 mm, and the insertion hole diameter is 22.4 mm.

[0071] The protective part 30 has a housing part on the base end side with a diameter of 45.2 mm and a depth of 37 mm, in which the tip part of the cable gland is housed and adhered with a silicone adhesive.

[0072] (Comparative Example 1) As a comparative example of the present invention, a cable assembly 1' was produced in which the protective portion 30 was removed from Example 1, and this was designated Comparative Example 1.

[0073] (Evaluation method) The evaluation items for the cable assembly 1 include bending resistance (durability), vibration during operation, amount of dust generated, etc., and vibration during operation was evaluated for the example and comparative example. The test method is described below.

[0074] For the test, a twisting and bending tester 50 shown in FIG. 6 was used.

[0075] A cable gland identical to that used as the separate mounting part 48 is fixed to the other end of the cable 10, a predetermined distance away from the tip of the protective part 30 provided at one end of the cable 10 (the tip of the cable gland in Comparative Example 1), to form a test sample.

[0076] The test sample is arched, and one end and the other end of the cable assembly 1 are fixed to a testing machine. One end of the testing machine is a non-working fixed end, and the other end is a working end, and the working end is twisted ±150 degrees at 80 reciprocating revolutions per minute.

[0077] The distance between one end and the other end is 900 mm in cable length, and the linear distance 51 when the testing machine is viewed from above in a plane is 400 mm.

[0078] The other end to be twisted is higher than the one end, and the twisted and bent part height 52 is 160 mm. Since the one end is fixed from the arch-shaped state and the other end is twisted, the cable assembly 1 is subjected to a bending load in addition to the twisting load.

[0079] As for the vibration during operation, the state of vibration of the cable assembly 1 while the test machine was in operation was evaluated visually and by using images.

[0080] (Evaluation results) The difference in the state of vibration between the example and the comparative example will be described.

[0081] The state of the vibration during the test is shown in Figures 7(a) to (d). Compared to the vibration amplitude L' of Comparative Example 1 shown on the left side of Figure 7(d), the vibration amplitude L of Example 1 shown on the right side of Figure 7(d) is reduced to about 77%. The reduction in the vibration amplitude can be confirmed visually, and it can be concluded that the load on the cable assembly 1 is reduced by the connection part 20 of the present invention. [Industrial Applicability]

[0082] The cable assembly of the present invention suppresses cable vibration during complex movements and is also expected to suppress dust generation at the connection points, making it suitable for use as a wiring component in locations where complex movements are repeated, such as in industrial robots. [Explanation of symbols]

[0083] 1 Cable Assembly 10 Cable 11 Sheath 12A, 12B, 12C wire 13A, 13B, 13C Wire Unit 14A, 14B, 14C tubes 20 Connection 30 Protection Department 31 Convex structure part 40 Mounting part 41 Male thread 42 Nut 43 Charging end 44 Sliding section 45 Support part 46 Groove 48 Separate mounting part 50 Twisting and bending tester 51 Straight line distance 52 Twisted bend height L swing width

Claims

1. A cable assembly comprising a cable having a sheath that covers a conductor or one or more electric wires, and a connection portion provided on the sheath, wherein the connection portion comprises an attachment portion that enables the cable assembly to be attached to an attachment object, and a protective portion that covers the sheath.

2. 2. The cable assembly according to claim 1, wherein the mounting portion and the protection portion are integrally molded.

3. 2. The cable assembly according to claim 1, wherein the attachment portion is a separate attachment portion that is separate from the protection portion.

4. 4. The cable assembly according to claim 3, wherein the protective portion is capable of accommodating at least a portion of the separate mounting portion.

5. 5. The cable assembly according to claim 1, wherein the rigidity of the protective portion decreases from the base end side to the tip end side.

6. 6. The cable assembly according to claim 5, wherein the rigidity of the tip end side of the protective portion is 3 to 10% of the rigidity of the base end side of the protective portion.

7. 5. The cable assembly according to claim 1, wherein the cross-sectional area of ​​the face perpendicular to the longitudinal direction of the protective portion decreases from the base end side to the tip end side.

8. 8. The cable assembly according to claim 7, wherein the cross-sectional area of ​​the tip end side of the protective portion is 3 to 10% of the cross-sectional area of ​​the base end side of the protective portion.

9. 5. The cable assembly according to claim 1, wherein the rigidity of the tip end side of the protective portion is 10 to 25% of the rigidity of the cable.

10. 6. The cable assembly according to claim 5, wherein the rigidity of the tip end side of the protective portion is 10 to 25% of the rigidity of the cable.

11. 8. The cable assembly according to claim 7, wherein the rigidity of the tip end side of the protective portion is 10 to 25% of the rigidity of the cable.

12. 5. The cable assembly according to claim 1, wherein a convex structure is provided on a bottom surface of the protective portion.

13. 6. The cable assembly according to claim 5, wherein a convex structure is provided on a bottom surface of the protection portion.

14. 8. The cable assembly according to claim 7, wherein a convex structure is provided on a bottom surface of the protection portion.

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