KR102348281B1 - Movable Robot Cable - Google Patents

Abstract

The present invention relates to a cable for a robot, wherein the cable for a robot according to the present invention includes a central interposition, at least one inner core surrounding the central interposition, and at least one agent disposed between the central interposition and the inner core. One interposition, an inner binding tape configured of an unsintered fluororesin for binding to surround the inner core and the first interposition, at least one outer core enclosing the outer side of the inner binding tape, an outer side of the inner binding tape At least one second interposition provided in the outer binding tape binding the outer core and the second interposition and composed of an unsintered fluororesin, a shielding layer provided on the outside of the outer binding tape, the shielding layer It is characterized in that it includes a sheath provided on the outside of the.

Description

Cable for Robot {Movable Robot Cable}

The present invention relates to a robot cable, and more particularly, to a robot cable having extremely improved durability against repeated twisting and bending lifespan so that it can be used in industrial robots.

In general, industrial robots perform various tasks such as welding, painting, and transport in a machine part production line. Such an industrial robot is connected to a central control unit by a robot cable, receives power required through the robot cable, and further transmits and receives information necessary for various tasks.

However, in this work process, the industrial robot is continuously moved or moved, and thus, fatigue loads such as repetitive tension, torsion, and bending are applied to the robot cable connected to the industrial robot.

In this case, disconnection of the conductor of the cable for the robot may occur, and when the production line is stopped due to the disconnection, significant time and cost loss for cable replacement occurs. Accordingly, there is a need for a robot cable that guarantees high durability.

In order to solve the above problems, an object of the present invention is to provide a cable for a robot that can significantly increase durability and fatigue life even when used in an environment where torsion or bending frequently acts.

In order to solve the above problems, the present invention is a central intervening; at least one inner core surrounding the central interposition; at least one first interposition surrounding the central interposition and disposed between the inner cores; an inner binding tape that surrounds and binds the inner core and the first interposition and made of an unsintered fluororesin; at least one outer core surrounding the outer side of the inner binding tape; at least one second interposition provided on the outside of the inner binding tape; an external binding tape binding the outer core to the second interposition and made of an unsintered fluororesin; a shielding layer provided on the outside of the external binding tape; and a sheath provided on the outside of the shielding layer.

In this case, the inner core includes a first conductor in which a plurality of first wire rods are twisted at a predetermined first pitch, and a first insulating layer provided outside the first conductor, wherein the first pitch is the second It may correspond to 15 to 30 times the outer diameter of one conductor.

In addition, the outer core includes a second conductor in which a plurality of second wire rods are twisted at a second predetermined pitch, a core part in which the plurality of second conductors are twisted in a third predetermined pitch, and is provided outside the core part and a second insulating layer to be used, the second pitch may correspond to 15 to 50 times the outer diameter of the second conductor, and the third pitch may correspond to 10 to 30 times the outer diameter of the core part. .

In addition, the yield strength increase rate of the first wire rod and the second wire rod of the inner core and the outer core may be 1% to 30%.

In addition, the unsintered (unsintered) fluororesin may be made of unsintered PTFE (Unsintered Polytetrafluoroethylene) resin.

Here, the inner binding tape and the outer binding tape may have a coefficient of friction between 0.05 and 0.2.

In addition, the first interposition and the second interposition may have outer diameters corresponding to the outer diameters of the inner core and the outer core, respectively.

Here, the outer diameter of the first interposition and the second interposition may have an outer diameter of 80% to 120% of the outer diameter of the inner core and the outer core.

In this case, at least one of the central interposition, the first interposition, and the second interposition may be formed by twisting an elastic yarn.

In addition, the stretchable yarn may be composed of a polyester yarn.

In addition, an additional binding tape may be further provided between the shielding layer and the sheath.

In this case, the additional binding tape may be composed of unsintered polytetrafluoroethylene (PTFE) resin.

In this case, the sheath may be formed by a tube type extrusion.

In addition, in order to solve the above problems, the present invention is a plurality of inner cores disposed on the outer peripheral surface of the central intervening circular cross-section; an inner binding tape for binding the inner core to the outside; a plurality of outer cores disposed on an outer circumferential surface of the inner binding tape; an external binding tape binding the outside of the outer core; a shielding layer provided on the outside of the external binding tape; and a sheath provided on the outside of the shielding layer, wherein the inner binding tape and the outer binding tape are made of unsintered fluororesin having a friction coefficient between 0.05 and 0.2. Provides a robot cable can do.

According to the robot cable according to the present invention, durability and fatigue life can be significantly increased even when used in an environment where torsion or bending frequently acts.

In addition, according to the cable for a robot according to the present invention, durability is improved, and since it is possible to minimize the process interruption in the industrial site, it is possible to minimize the loss due to the process interruption.

1 is a cross-sectional view showing the internal configuration of a cable for a robot according to an embodiment of the present invention;
2 and 3 are graphs showing the resistance change rate according to the number of twists in Examples and Comparative Examples according to the present invention;
4 is a graph comparing the difference in friction coefficient when the binding tape according to the present invention and the conventional binding tape are applied;
5 is a graph comparing the change in pull-out force of the Example and Comparative Example according to the present invention;
6 is a graph showing the resistance change rate (%) according to the number of twists in Examples and Comparative Examples according to the present invention.

Hereinafter, a robot cable according to an embodiment of the present invention will be described in detail with reference to the drawings.

1 is a cross-sectional view showing the internal configuration of a cable 100 for a robot according to an embodiment of the present invention.

Referring to FIG. 1 , the robot cable 100 includes a central interposition 20 , at least one inner core 10 surrounding the central interposition 20 , and the inner core surrounding the central intervening 20 . (10) at least one first interposition 22 disposed between, and binding (binding) surrounding the inner core 10 and the first interposer 22, and an inner binding tape made of an unsintered fluororesin (30), at least one outer core 40 surrounding the outer side of the inner binding tape 30, at least one second interposition 50 provided on the outer side of the inner binding tape 30, the outer core An external binding tape 32 that binds the 40 and the second interposition 50 and made of an unsintered fluororesin, a shielding layer 60 provided on the outside of the external binding tape 32, and the shielding A sheath 70 provided outside the layer 60 is included.

In the robot cable 100, the inner core 10 may be configured for communication to and from the outside, and the outer core 40 may be configured for power supplying power.

Specifically, the inner core 10 includes a first conductor 13 in which a plurality of first wires 12 are twisted at a predetermined first pitch, and is provided on the outside of the first conductor 13 . A first insulating layer 14 is provided.

The first wire 12 may be made of a material such as copper, and the first insulating layer 140 covering the first conductor 13 made of the first wire 12 is polyethylene (PE, PE, Polyethylene) or high-density polyethylene (HDPE, High Density Polyethylene), etc.

However, when the first wire 12 is subjected to the above-described process to form the inner core 10 , a tensile stress may remain in the first wire 12 . As such, when the tensile stress remains in the first wire 12 after forming the inner core 10, it means that the tensile pre-strain is high, and in this case, the first wire 12 The yield strength of can be increased, for example, it can be increased by 30% or more.

As such, when the yield strength of the first wire 12 is increased, the fatigue life of the first wire 12 is reduced, and damage such as a crack occurs in the first wire 12 . will do This damage to the first wire 12 can be expressed as a resistance change rate (%) that changes the resistance.

That is, when the resistance change rate (%) is relatively high, it means that a lot of damage such as cracks has occurred in the first wire 12, and in severe cases, it may lead to disconnection.

2 is a graph showing the resistance change rate according to the number of twists in Examples and Comparative Examples according to the present invention. In the embodiment, the increase rate of the yield strength is 1% to 30% after forming the inner core 10, and in the comparative example, the increase rate of the yield strength after forming the inner core 10 It means a wire rod exceeding this 30%. In the graph of FIG. 2 , the horizontal axis represents the number of twists (x1000 times), and the vertical axis represents the change rate (%) of resistance.

As shown in FIG. 2 , in the case of the embodiment, even when the number of twists exceeds 10,000 times, the resistance change rate corresponds to about 7%, so it can be seen that the resistance change rate is very small. It can be seen that in the case of the wire rod of the above embodiment, damage such as cracks is relatively small, which is also due to the relatively small pre-strain in the wire rod of the above embodiment, so that the increase rate of the yield strength is 30% or less, that is, 1% to 30% It can be seen that it corresponds to

On the other hand, in the case of the comparative example, when the number of twists exceeds 10,000 times, the resistance change rate corresponds to about 13% or more, indicating that the resistance change rate is relatively large. It can be seen that, in the case of the wire rod of the comparative example, damage such as cracks occurred relatively very much, and it can also be seen that the increase rate of the yield strength exceeded 30% because the wire rod of the comparative example had a relatively large pre-strain.

Therefore, it can be seen that the fatigue life becomes longer as the pre-strain is relatively small after processing the wire rod, and the fatigue life can be predicted indirectly through the increase rate of yield strength or the rate of change of resistance after processing the wire rod.

Therefore, if the increase rate of the yield strength or the change rate of resistance is set according to a predetermined threshold value after processing the wire rod, the fatigue life can be increased. For example, in the present invention, when the increase rate of yield strength is 1% to 30%, that is, less than 30%, or when the rate of change of resistance is 1% to 25%, that is, 25% or less after processing the wire rod, the threshold is set can

The inventors of the present invention conducted an experiment to confirm the factors affecting the resistance change rate of the wire rod, and FIG. 3 shows the results.

3 is a graph showing the resistance change rate according to the number of twists in Examples and Comparative Examples according to the present invention. In the above embodiment, a plurality of wire rods form a conductor twisted at a predetermined pitch ('aggregate type'), and the plurality of conductors form a core part twisted at a predetermined pitch again ('composite type'). In the comparative examples, a plurality of wire rods are twisted at a predetermined pitch to form a conductor ('aggregate type'). In the case of the comparative example and the example, the entire outer diameter is formed to be the same.

In this case, Comparative Example 1 is formed such that the pitch of the wire rod is relatively larger than that of Big Bridge Example 2. For example, in Comparative Example 1, the pitch of the wire corresponds to about 18 mm, and in Comparative Example 2, the pitch of the wire corresponds to about 12 mm. In the graph of FIG. 3 , the horizontal axis represents the number of twists (x1000 times), and the vertical axis represents the change rate (%) of resistance.

As shown in FIG. 3 , it can be seen that the resistance change rate (%) according to the increase in the number of twists for the wire rod of the embodiment after processing through the aggregate type and the composite type is significantly superior to that of the comparative examples.

That is, in the case of the wire rod of the above embodiment, even when the number of twists exceeds 10,000 times, it can be seen that the resistance change rate (%) corresponds to approximately 12% and is very small.

On the other hand, in the case of the wire rod of Comparative Example 2 that passed through only the set type, it can be seen that the resistance change rate (%) exceeds about 25% when the number of twists exceeds about 2,000 times.

On the other hand, in the case of the wire of Comparative Example 1, when the number of twists exceeds 10,000 times, the resistance change rate (%) corresponds to about 23%, which is superior to Comparative Example 2, but the resistance change rate compared to the Example You can see this is bigger.

As a result, it can be seen that the resistance change rate is relatively the smallest when both the aggregate type and the composite type are processed in the case of processing the wire rod. In addition, it can be seen that, when only the aggregate type is passed, the resistance change rate is small as the pitch of the wire rod is relatively large.

As shown in FIG. 1 , the first conductor 13 of the inner core 10 may be formed in an aggregate type. In this case, the first pitch of the first wire 12 may correspond to 15 to 30 times the outer diameter of the first conductor 13 . When it is less than 15 times as described above, the resistance change rate of the first wire 12 exceeds 25%, or the increase rate of the yield strength exceeds 30%. On the other hand, if it is greater than 30 times, the pitch becomes too long, so that it is impossible to properly form the first conductor 13 in a circular shape.

That is, when the first pitch of the first wire 12 falls within the above-described range, the yield strength increase rate of the first wire 12 of the inner core 10 corresponds to 1% to 30%, and the resistance The rate of change (%) corresponds to 1% to 25%.

On the other hand, a central interposition 20 is provided in the central portion of the inner core 10 . The central interposition 20 serves to maintain the circular shape of the robot cable 100 together with the first intervening intervening 22 and the second intervening intervening 50 to be described later.

In the case of a conventional cable, it is composed of a PVC string, polyethylene (PE: polyethylene), EPDM (ethylene propylene diene monomer), and the like when constituting the interposition.

In the case of a conventional cable, when bending or torsion is applied to the cable, friction occurs rather than slip between the insulator and the interposition of the core. Damage or disconnection may occur.

[Table 1] below shows the results of measuring the resistance of the inner core 10 after the torsion test of 500,000 times of Examples and Comparative Examples having the same structure. The above embodiment refers to a case in which the central interposition 20, the first intervening material 22, and the second intervening material 50 are formed by twisting an elastic yarn made of a polyester yarn, and the comparison The example shows the case formed by EPDM. The inner core 1 to the inner core 5 correspond to arbitrarily numbering the inner core 10 shown in FIG. 1 .

Resistance of Comparative Example (mΩ) Resistance of the embodiment (mΩ) inner core 1 18.27 7.1 inner core 2 18.05 7.6 inner core 3 37.5 8.2 inner core 4 16.06 7.1 inner core 5 28.07 7.5

In [Table 1], the threshold value can be changed according to the place where the cable is installed, the work process, the request of the customer, etc., but corresponds to approximately 8.25 mΩ.

In this case, in the case of the comparative example, it can be seen that the resistance values of all internal cores have a value greater than or equal to the threshold value, and thus the reference value is not satisfied.

On the other hand, in the case of the above embodiment, it can be seen that the maximum resistance value corresponds to 8.2 mΩ, which satisfies the reference value. In the case of the embodiment, since the interposition is made of highly elastic yarn, even when torsion or the like is applied, only a relatively small amount of stress is transmitted to the inner core, thereby preventing an increase in resistance due to damage to the internal stress.

Accordingly, in the present invention, at least one of the central interposition 20, the first interposition 22, and the second interposition 50 may be formed by twisting an elastic yarn, and the elastic yarn is a polyester yarn. (polyester yarn).

As shown in FIG. 1 , the central interposition 20 is positioned at the center, and at least one inner core 10 and the first intervening intervening 22 are disposed along the outside of the central interposition 20 .

In the drawings, the number of the inner core 10 is shown as 5 and the number of the first interposition 22 is shown as 3, but this is only an example and can be appropriately modified.

On the other hand, since the inner core 10 and the first interposition 22 together form a circular shape, the first interposition 22 preferably has an outer diameter corresponding to the outer diameter of the inner core 10 , respectively.

Since the outer diameter of the inner core 10 can be determined according to the working environment to which the robot cable 100 is applied, the outer diameter of the first interposition 22 is determined to correspond to the outer diameter of the inner core 10 it is preferable

For example, the outer diameter of the first interposition 22 may have an outer diameter of 80% to 120% of that of the inner core 10 .

If the outer diameter of the first interposition 22 is relatively large, pressure may be applied to the inner core 10 during a torsion action, and damage such as disconnection may occur in the first conductor 13 of the inner core 10 . have. In addition, when the outer diameter of the first interposition 22 is relatively small, the circular shape cannot be achieved.

Meanwhile, the inner binding tape 30 surrounds and binds the inner core 10 and the first interposition 22 to maintain a circular shape.

In the case of a conventional cable, a nonwoven fabric or a sintered fluororesin was used as a binding tape. However, in the case of sintered fluororesin, the strength and coefficient of friction are relatively high, and thus, when torsion or the like is applied to the cable, the stress cannot be absorbed and the stress is transferred to the inner core. In addition, when torsion or the like acts on the cable, it may cause damage to the inner core due to friction between the binding tape and the inner core.

Therefore, in the case of the present invention, the inner binding tape 30 may be made of an unsintered fluororesin having a relatively small coefficient of friction and strong lubricity.

For example, the unsintered fluororesin may be made of unsintered polytetrafluoroethylene (PTFE) resin. At this time, it was confirmed that the inner binding tape 30 can be configured to have a coefficient of friction between 0.05 and 0.2. The binding tape 30 having such a coefficient of friction enables smooth slipping when torsion is applied to the cable, thereby minimizing frictional damage between the binding tape and the outer core 40, thereby greatly improving the durability of the cable.

Figure 4 is a graph comparing the difference in friction coefficient in the case of applying the binding tape (B) according to the present invention and the conventional binding tape (A).

In Figure 4, the binding tape (B) according to the present invention shows a case composed of unsintered PTFE (Unsintered Polytetrafluoroethylene) resin, and a case where the conventional binding tape is applied (A) shows a case where a sintered fluororesin is applied.

As shown in FIG. 4, when the conventional binding tape is applied (A), the friction coefficient corresponds to about 0.146 μ, whereas the binding tape according to the present invention (B) corresponds to 0.092 μ, which is a friction coefficient of about 37%. It can be seen that a decrease in

On the other hand, Figure 5 is a graph comparing the change of the pull-out force (N) of the Example according to the present invention and the comparative example.

5, the embodiment shows a case in which the inner binding tape 30 is made of unsintered polytetrafluoroethylene (PTFE) resin, and the comparative example shows a case where a sintered fluororesin is used as the binding tape. In addition, the pull-out force is defined as a force (N) required by friction with the outer core when the inner core is pulled out. That is, as the pull-out force is relatively large, the frictional force between the inner core and the outer core by the inner binding tape 30 is greater. It means that the friction force between the inner core and the outer core is small. In FIG. 5 , the horizontal axis shows the length (mm) from which the inner core is pulled out, and the vertical axis shows the applied force (N).

Referring to FIG. 5 , in the case of the comparative example, it can be seen that the force required for pulling out the inner core decreases as the length of pulling out the inner core increases. For example, when the length from which the inner core is pulled out corresponds to about 100 mm, it can be seen that the required force corresponds to about 30 to 35 N.

On the other hand, it can be seen that in the case of the Example, the force required is relatively smaller than that of the Comparative Example. For example, when the length from which the inner core is pulled out corresponds to about 100 mm, the force required corresponds to about 15 N, and it can be seen that the force is reduced by about 50% to 57% compared to the comparative example.

In the case of the power communication cable 100 for movement according to the present invention, since twisting, bending, etc. frequently act due to frequent movement, the smaller the pull-out force is, the smaller the pull-out force is between the inner core and the outer core by the inner binding tape 30 . It can be seen that the frictional force is small, which is advantageous for durability and fatigue life.

Meanwhile, referring to FIG. 1 , at least one outer core 40 and at least one second interposition 50 are provided on the outside of the inner binding tape 30 .

In this case, the outer core 40 may be formed by processing of the above-described aggregate and complex types.

For example, the outer core 40 may include a second conductor 43 in which a plurality of second wire rods 42 are twisted at a second predetermined pitch, and a third third conductor in which the plurality of second conductors 43 are twisted at a predetermined second pitch. It may include a core part 45 twisted at a pitch, and a second insulating layer 44 provided outside the core part 45 .

In this case, the second pitch corresponds to 15 to 50 times the outer diameter of the second conductor 43 , and the third pitch corresponds to 10 to 30 times the outer diameter of the core part 45 .

In addition, when the second pitch and the third pitch of the second wire 42 fall within the above-described ranges, the yield strength increase rate of the second wire rod 42 of the outer core 40 is 1% to 30%. The resistance change rate (%) corresponds to 1% to 25%.

On the other hand, the second interposition 50 has an outer diameter corresponding to the outer diameter of the outer core 40 , for example, the outer diameter of the second interposition 50 is 80 compared to the outer diameter of the outer core 40 . % to 120% of the outer diameter.

In addition, the second interposition 50 may be formed by twisting an elastic yarn, and the elastic yarn may be formed of a polyester yarn.

Since the description of the second interposition 50 is similar to the description of the above-described first interposition 22 , a repetitive description will be omitted.

In the drawings, the number of the outer core 40 is shown as 8 and the number of the second interposition 50 is shown as 1, but this is only an example and can be appropriately modified.

On the other hand, the outer binding tape 32 binds the outer core 40 and the second interposition 50, and is made of an unsintered fluororesin. In this case, the unsintered fluororesin may be made of unsintered polytetrafluoroethylene (PTFE) resin, and the external binding tape 32 may have a friction coefficient between 0.05 and 0.2.

Since the description of the external binding tape 32 is similar to the description of the internal binding tape 30 described above, a repetitive description will be omitted.

A shield layer 60 is provided on the outside of the external binding tape 32 . The shielding layer 60 may be formed of a metal tape or metal braid by applying a material such as copper, aluminum, a copper alloy, or an aluminum alloy. The shielding layer 60 functions to maintain the communication characteristics of the communication cable by electromagnetic wave shielding or to protect the cable from external impact.

On the other hand, the outer side of the shielding layer 60 is provided with a sheath (70). It is responsible for the outermost layer of the power communication cable 100 for movement of the sheath 70, prevents the aforementioned internal components from being exposed to the outside, and serves to protect the internal components from external impact.

At this time, in the case of a conventional cable, in the case of extruding the sheath, it was faithfully extruded and molded, but this method entails a problem in that the conductor or shielding layer inside is pressed by the sheath after extrusion.

Therefore, in the present invention, when the sheath 70 is extrusion-molded, it is molded by a tube type extrusion. It is a process of extruding while inserting internal components into the inside of the sheath 70 in a state in which the sheath 70 is prepared in advance in the form of a tube. can be prevented

Meanwhile, as shown in FIG. 1 , an additional binding tape 34 may be further provided between the shielding layer 60 and the sheath 70 . By providing the additional binding tape 34, it is possible to further reduce the internal frictional force when torsion or bending acts on the robot cable 100.

At this time, the additional binding tape 34 is made of unsintered PTFE (Unsintered Polytetrafluoroethylene) resin, and has a coefficient of friction between 0.05 and 0.2. Since the description of the additional binding tape 34 is similar to the above-described inner binding tape 30 and the external binding tape 32, a repetitive description will be omitted.

6 is a graph showing the resistance change rate (%) according to the number of twists in Examples and Comparative Examples according to the present invention.

In FIG. 6, the embodiment corresponds to the cable having the configuration of FIG. 1 described above, and the comparative example applies high density polyethylene (HDPE, high density polyethylene) or EPDM as an intervening, and applies a sintered fluororesin as a binding tape, and a sheath is formed by solid extrusion. In FIG. 6 , the horizontal axis shows the number of twists (x1000 times), and the vertical axis shows the resistance change rate (%).

As shown in FIG. 6 , in the case of the cable according to the comparative example, it can be seen that the resistance change rate exceeds the reference value of 25% when the number of twists reaches approximately 20,000 to 25,000 times.

On the other hand, in the case of the cable according to the embodiment of the present invention, even when the number of twists exceeds 500,000, the resistance change rate does not exceed 5.0%, which is significantly smaller than the reference value of 25%.

Although described with reference to preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention within the scope without departing from the spirit and scope of the present invention described in the claims described below. There will be. Therefore, if the modified implementation basically includes the elements of the claims of the present invention, it should be considered that all of them are included in the technical scope of the present invention.

10: inner core
20: center intervening
22: first interposition
30: inner binding tape
32: external binding tape
34: additional binding tape
40: outer core
50: second interposition
60: shielding layer
70: sheath
100: cable for robot

Claims (14)

central intervening;
a plurality of inner cores surrounding the central interposition;
at least one first interposition surrounding the central interposition and disposed between the inner cores;
an inner binding tape made of an unsintered fluororesin, which binds by surrounding the inner core and the first interposition in a contact state;
a plurality of outer cores surrounding and in contact with the outer circumferential surface of the inner binding tape;
at least one second interposition provided on the outside of the inner binding tape; an external binding tape binding the outer core to the second interposition and made of an unsintered fluororesin; a shielding layer provided on the outside of the external binding tape; and, a sheath provided on the outside of the shielding layer;
The inner core includes a first conductor in which a plurality of first wires are twisted at a predetermined first pitch, and a first insulating layer provided on the outside of the first conductor, wherein the first pitch is equal to that of the first conductor. A cable for a robot, characterized in that it corresponds to 15 to 30 times the outer diameter. delete According to claim 1,
The outer core includes a second conductor twisted by assembling a plurality of second wire rods at a second predetermined pitch, a core part twisted by combining the plurality of second conductors with a third predetermined pitch, and an outer side of the core part and a second insulating layer provided on Robot cable, characterized in that. 4. The method of claim 3,
The cable for a robot, characterized in that the yield strength increase rate of the first and second wires of the inner core and the outer core is 1% to 30%. According to claim 1,
The unsintered (unsintered) fluororesin is a robot cable, characterized in that made of unsintered PTFE (Unsintered Polytetrafluoroethylene) resin. According to claim 1,
The cable for a robot, characterized in that the inner binding tape and the outer binding tape have a coefficient of friction between 0.05 and 0.2. According to claim 1,
The cable for a robot, characterized in that the first interposition and the second interposition have outer diameters corresponding to the outer diameters of the inner core and the outer core, respectively. 8. The method of claim 7,
The outer diameter of the first interposition and the second interposition is a robot cable, characterized in that it has an outer diameter of 80% to 120% compared to the outer diameter of the inner core and the outer core. According to claim 1,
At least one of the central interposition, the first interposition, and the second interposition is formed by twisting an elastic yarn. 10. The method of claim 9,
The elastic yarn is a cable for a robot, characterized in that made of a polyester yarn. According to claim 1,
Robot cable, characterized in that it further comprises an additional binding tape between the shielding layer and the sheath. 12. The method of claim 11,
The additional binding tape is a robot cable, characterized in that made of unsintered PTFE (Unsintered Polytetrafluoroethylene) resin. According to claim 1,
The sheath is a cable for a robot, characterized in that it is formed by extrusion of a tube type. a plurality of inner cores disposed on the outer circumferential surface of the central intervening core having a circular cross section, the plurality of inner cores having a conductor twisted at a pitch of 15 to 30 times the outer diameter and an insulating layer provided on the outside of the conductor; an inner binding tape for binding the inner core outside in a contact state; a plurality of outer cores disposed in contact with the outer circumferential surface of the inner binding tape; an external binding tape for binding the outside of the outer core; a shielding layer provided on the outside of the external binding tape; and a sheath provided on the outside of the shielding layer, wherein the inner binding tape and the outer binding tape are made of unsintered fluororesin having a friction coefficient between 0.05 and 0.2.

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