Flexible power cable for robots / robotic arms

Abstract

The present invention relates to the technical field of power cables, and particularly to a flexible power cable for a robot / robotic arm, which comprises a reinforcing cable core, a conductive unit, a limiting and buffering layer, a flame-retardant wrapping layer, an outer insulating layer and an outer sheath. The limiting and buffering layer includes rigid bars and elastic strips fixedly arranged on both sides thereof along the length direction. Among them, when the cable is bent, the areas where adjacent rigid bars are located inside the bent part of the cable are pressed inward. The inwardly pressed rigid bars compress the elastic strips and the buffer strips. During the process of contraction of the elastic strips and the buffer strips, the extrusion force is buffered, ensuring that the cable has good resilience. At the same time, when the elastic strips and the buffer strips are extruded to the contraction limit, the rigid bars cannot continue to compress the elastic strips and the buffer strips. At this time, the overall cable cannot continue to reduce the bending radius, which can effectively protect the cable from damage to the insulating sheath caused by too small a bending radius during bending and improve the overall safety of the cable.

Description

Technical Field

[0001] The present invention relates to the technical field of power cables, and more particularly to a flexible power cable for robots / robotic arms. Background Art

[0002] Industrial multi-degree-of-freedom robots mostly use articulated robots (also known as multi-joint robotic arms), which have extensive practical applications in industries such as additive manufacturing, laser welding, laser cutting, packaging, loading and unloading, flexible assembly, marking, gluing, high-precision assembly, etc. in the 3C, automotive, food, machinery, pharmaceutical, glass, and plastic product industries. Through the coordinated movement of each degree-of-freedom joint, the actuator at the end of the robot completes the corresponding operation.

[0003] The joint part of the robot is equipped with a rotatable flexible joint composed of a joint rotating motor, a reducer, an encoder, a sensor, etc. The control signals of the system for each flexible joint are transmitted from inside the base of the robot through power lines (power cables) and control lines (weak wires for transmitting control signals) to the joint rotating motor. The rotating motors of each joint rotate correspondingly to adjust the position and posture of the entire robot and achieve the work operation. During the operation process, if sufficient flexibility and redundancy are reserved for the cables, during the rotation of the robot in all directions, the repeated twisting, bending, etc. of the cables will cause less damage to the cables. According to normal design standards and specifications, the lifespan of the cables of the robot is at least more than 100,000 times of bending without cracking and maintaining good electrical performance.

[0004] However, in some design scenarios, for reasons such as cost savings, the cables used on robots usually have insufficient redundancy, and only flexible cables with a multi-layer wrapping and winding design are used in traditional designs. Considering the weight, it is hoped to minimize the weight of the robot cables to reduce the load impact of the cable self-weight on the robotic arm. As a result, on the premise of meeting performance standards such as insulation, temperature resistance, and corrosion resistance, the coating layer of the cable is made as thin as possible. After repeated bending and twisting for a certain period of time, especially when the length redundancy is just right or slightly longer, the phenomenon of cable cracking is serious, and even the insulation sheath may be damaged due to excessive extrusion pressure caused by too small a bending angle, resulting in electric leakage due to the exposure of the cable core and forming a safety hazard. Summary of the Invention

[0005] In view of the defects and deficiencies of the prior art, the first aspect of the present invention provides a flexible power cable for robots / robotic arms, comprising:

[0006] A strengthened cable core, and a plurality of equally spaced isolation members are integrally formed circumferentially on the outer wall of the strengthened cable core;

[0007] A plurality of conductive units, with the plurality of conductive units respectively distributed between the plurality of spacers;

[0008] A limit buffer layer, spirally wound around the outer walls of the plurality of conductive units along the length direction, and the winding has no overlap;

[0009] A flame-retardant wrapping layer, covering the outer wall of the limit buffer layer;

[0010] An outer insulation layer, covering the outer wall of the flame-retardant wrapping layer;

[0011] An outer sheath, covering the outer wall of the outer insulation layer;

[0012] Wherein, the limit buffer layer includes a rigid stop bar and elastic strips fixedly arranged on both sides thereof along the length direction, and a buffer strip is embedded inside the elastic strip along its length direction.

[0013] Preferably, adhesive layers are coated on both side surfaces of the rigid stop bar, and the elastic strips are adhered to both side surfaces of the rigid stop bar through the adhesive layers.

[0014] Preferably, the surfaces of the long sides on both sections of the rigid stop bar, the elastic strip and the buffer strip are inclined surfaces with the same inclination angle, and are used for mutual embedding and winding.

[0015] Preferably, the elastic strip is a flame-retardant and heat-insulating elastic strip.

[0016] Preferably, the outer sheath is a flame-retardant PVC layer.

[0017] Preferably, the conductive unit includes a conductor core and an inner sheath arranged in sequence from the inside to the outside.

[0018] Preferably, the inner sheath is an XLPE insulation layer.

[0019] Compared with the prior art, the remarkable beneficial effects of the flexible power cable for robots / robotic arms of the present invention are as follows:

[0020] Through the structural optimization design of the cable, a plurality of equally spaced spacers are integrally formed circumferentially on the outer wall of the strengthened cable core, and a plurality of conductive units are respectively distributed between the plurality of spacers. Then, a limit buffer layer with a rigid stop bar and rubber strips is covered outside the conductive unit, spirally wound around the outer wall of the conductive unit along the length direction, and the winding has no overlap. Thus, when the cable is repeatedly bent and twisted, the adjacent rigid stop bars squeeze inward in the area inside the bending part of the cable, and expand outward in the area outside the bending part of the cable. The inwardly squeezing rigid stop bars compress the elastic strips and the buffer strips, and the elastic strips and the buffer strips buffer the squeezing force during the contraction process, ensuring that the cable has good resilience.

[0021] Meanwhile, when the elastic strip and the buffer strip are squeezed to the contraction limit, the rigid stop strip cannot continue to compress the elastic strip and the buffer strip. At this time, the overall cable cannot continue to reduce the bending radius, which can effectively protect the cable from damage to the insulating sheath caused by too small a bending radius during bending and improve the overall safety of the cable.

[0022] It should be understood that all combinations of the foregoing concepts and additional concepts described in more detail below are considered to be part of the inventive subject matter of the present disclosure as long as such concepts are not mutually inconsistent. Additionally, all combinations of the claimed subject matter are considered to be part of the inventive subject matter of the present disclosure.

[0023] The foregoing and other aspects, embodiments, and features of the teachings of the present invention can be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the present invention, such as the features and / or beneficial effects of exemplary embodiments, will be apparent from the following description or will be learned through practice of specific embodiments in accordance with the teachings of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in various figures may be represented by the same reference numeral. For clarity, not every component is labeled in each figure.

[0025] Figure 1 is a schematic structural diagram of a flexible power cable for a robot / robotic arm shown in the present invention.

[0026] Figure 2 is a perspective view of a flexible power cable for a robot / robotic arm shown in the present invention.

[0027] Figure 3 is a schematic axial sectional view of a limit buffer layer of a flexible power cable for a robot / robotic arm shown in the present invention.

[0028] Figure 4 is a schematic axial sectional view of a limit buffer layer at the bending part of a flexible power cable for a robot / robotic arm shown in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] To better understand the technical content of the present invention, specific embodiments are given below in conjunction with the accompanying drawings for illustration.

[0030] Aspects of the present invention are described with reference to the accompanying drawings, in which a number of illustrative embodiments are shown. The embodiments of the present disclosure are not necessarily intended to include all aspects of the present invention. It should be understood that the various concepts and embodiments introduced above, as well as those concepts and embodiments described in more detail below, can be implemented in any of a number of ways, because the concepts and embodiments disclosed in the present invention are not limited to any embodiment. Additionally, some aspects of the present invention can be used alone, or in any suitable combination with other aspects of the present invention.

[0031] Combined with Figure 1 and Figure 2 The flexible power cable for a robot / robotic arm shown in the illustrated embodiment includes a strengthening cable core 1, a conductive unit 2, a limiting and buffering layer, a flame-retardant wrapping layer 5, an outer insulation layer 6, and an outer sheath 7.

[0032] Wherein, a plurality of equally spaced isolation members 11 are integrally formed circumferentially on the outer wall of the strengthening cable core 1. In the illustrated example, four isolation members 11 are taken as an example for illustration.

[0033] In an alternative embodiment, both the strengthening cable core 1 and the isolation members 11 are made of lightweight nylon material, which has a relatively high tensile strength and can effectively increase the overall tensile strength of the cable.

[0034] Thus, the isolation members 11 separate the plurality of conductive units 2, preventing the conductive units 2 from rubbing against each other during cable torsion, resulting in insulation damage and short circuit.

[0035] Furthermore, the plurality of conductive units 2 are respectively distributed between the plurality of isolation members 11.

[0036] The conductive unit 2 includes a conductor core 21 and an inner sheath 22 arranged in sequence from the inside to the outside, and the inner sheath 22 is an XLPE insulation layer.

[0037] In an alternative embodiment, the conductor core 21 is formed by stranding a plurality of copper wires, which has good flexibility. The inner sheath 22 is made of XLPE insulation material, which has good electrical insulation performance and a small bending radius, making the overall cable have a small bending radius.

[0038] Combined with Figure 2 、 Figure 3 and Figure 4 As shown, the limiting and buffering layer is spirally wrapped around the outer walls of the plurality of conductive units 2 along the length direction, and the wrapping has no overlap.

[0039] Furthermore, the limiting and buffering layer includes a rigid stop bar 3 and elastic strips 4 fixedly arranged on both sides thereof along the length direction.

[0040] Among them, a buffer strip 41 is embedded along the length direction inside the elastic strip 4. The elastic strip 4 is preferably a flame-retardant and heat-insulating elastic strip.

[0041] The rigid retaining strip 3 and the elastic strips 4 fixedly arranged on both sides thereof are spirally wound along the length direction of the cable, and the elastic strips 4 between adjacent wraps are tightly pressed against each other.

[0042] In an alternative embodiment, the material of the rigid retaining strip 3 is ABS plastic, which has a relatively high hardness and can effectively limit the bending angle.

[0043] The elastic strip 4 is a flame-retardant and heat-insulating rubber and plastic sponge, which has good heat-insulating and flame-retardant properties, a relatively low heat conduction efficiency, and reduces the aging rate of the buffer strip 41.

[0044] The material of the buffer strip 41 therein is chloroprene rubber, which has good mechanical properties. While effectively buffering the extrusion force, it has good aging resistance, heat resistance, oil resistance and chemical corrosion resistance.

[0045] In this way, when the cable is bent, the adjacent rigid retaining strips 3 in the area inside the bending part of the cable are squeezed inward. As shown in Figure 4 When the rigid retaining strip 3 that is squeezed inward compresses the elastic strip 4 and the buffer strip 41, the elastic strip 4 and the buffer strip 41 buffer the extrusion force during the contraction process, ensuring that the cable has good resilience. At the same time, when the elastic strip 4 and the buffer strip 41 are squeezed to the contraction limit, the rigid retaining strip 3 cannot continue to compress the elastic strip 4 and the buffer strip 41. At this time, the overall cable cannot continue to reduce the bending radius, which can effectively protect the cable from damage to the insulating sheath caused by too small a bending radius when bending, improve the safety of the cable. The adjacent rigid retaining strips 3 in the area outside the bending part of the cable expand outward and do not affect the bending of the cable.

[0046] Furthermore, adhesive layers 31 are coated on both side surfaces of the rigid retaining strip 3, and the elastic strips 4 are adhered to both side surfaces of the rigid retaining strip 3 through the adhesive layers 31. The elastic strips 4 are adhesively fixed to both side surfaces of the rigid retaining strip 3 through the adhesive layers 31 to prevent them from falling off.

[0047] In an alternative embodiment, the adhesive layer 31 uses a polyurethane flame-retardant adhesive, which has good adhesive performance and also has a good flame-retardant effect.

[0048] Furthermore, the long sides of the cross-sections of the rigid retaining strip 3, the elastic strip 4 and the buffer strip 41 are all inclined surfaces with the same inclination angle, and are used for mutual embedding and winding. When winding the limiting and buffering layer, the adjacent elastic strips 4 can be pressed against each other to improve the winding stability and prevent radial loosening during transmission.

[0049] Combined with Figure 1As shown, the flame-retardant wrapping layer 5 is wrapped around the outer wall of the limit buffer layer, the outer insulation layer 6 is wrapped around the outer wall of the flame-retardant wrapping layer 5, and the outer sheath 7 is wrapped around the outer wall of the outer insulation layer 6.

[0050] In an alternative embodiment, the flame-retardant wrapping layer 5 is wound with a flame-retardant mica tape, which not only wraps and fixes the limit buffer layer but also has good flame-retardant properties. The outer insulation layer 6 is made of XLPE insulation material, which has good electrical insulation properties and a small bending radius, enabling the overall cable to have a small bending radius.

[0051] Furthermore, the outer sheath 7 is a flame-retardant PVC layer, which is extruded with flame-retardant PVC and has the properties of resistance to sunlight aging and flame-retardant environmental protection.

[0052] Among them, outside the flame-retardant mica tape wrapping layer 5, the outer sheath 7 and the XLPE outer insulation layer 6 can be integrally formed by a co-extrusion process.

[0053] In another embodiment, a total shielding layer, such as a fine copper mesh or a mixed braided layer of copper mesh and fiber, is further provided between the XLPE outer insulation layer 6 and the outer sheath 7.

[0054] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention pertains can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope defined in the claims.

Claims

1. A flexible power cable for a robot / robotic arm, characterized in that, Including: A strengthening cable core, on the outer wall circumference of which a plurality of equally spaced isolation members are integrally formed circumferentially; A plurality of conductive units, which are respectively distributed between the plurality of isolation members; A limiting and buffering layer, which is spirally wound around the outer wall of the conductive unit along the length direction without overlap; A flame-retardant wrapping layer, which is coated on the outer wall of the limiting and buffering layer; An outer insulating layer, which is coated on the outer wall of the flame-retardant wrapping layer; An outer sheath, which is coated on the outer wall of the outer insulating layer; Wherein, the limiting and buffering layer includes a rigid retaining strip and elastic strips fixedly arranged on both sides thereof along the length direction, and a buffer strip is embedded in the elastic strip along its length direction; The rigid retaining strip and the elastic strips fixedly arranged on both sides thereof are spirally wound along the length direction of the cable, and the elastic strips between adjacent windings are tightly pressed against each other; The long sides of the cross-section of the rigid retaining strip, the elastic strip and the buffer strip are all inclined surfaces with the same inclination angle and are used for mutually embedding and winding; 2. The flexible power cable for a robot / robotic arm according to claim 1, characterized in that Adhesive layers are coated on both sides of the rigid retaining strip, and the elastic strips are adhered to both sides of the rigid retaining strip through the adhesive layers; 3. The flexible power cable for a robot / robotic arm according to claim 1, characterized in that, The elastic strip is a flame-retardant and heat-insulating elastic strip; 4. The flexible power cable for a robot / robotic arm according to claim 1, wherein, The outer sheath is a flame-retardant PVC layer; 5. The flexible power cable for a robot / robotic arm according to any one of claims 1-4, characterized in that, The conductive unit includes a conductor core and an inner sheath arranged in sequence from the inside to the outside; 6. The flexible power cable for a robot / robotic arm according to claim 5, characterized in that, The inner sheath is an XLPE insulating layer; 7. The flexible power cable for a robot / robotic arm according to claim 6, wherein, A total shielding layer is further arranged between the XLPE outer insulating layer and the outer sheath;

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