JP2020095824A - cable - Google Patents

Abstract

To provide a cable being hardly swung by oscillation generated by high-speed operation of a movable part so as to hardly generate breakage even when being wired in an arch shape over the movable part.SOLUTION: A cable comprises: a core material 2 comprising resin and disposed in a cable center; a plurality of electric wires 3 spirally twisted in the outer periphery of the core material 2; and a sheath 4 disposed so as to collectively cover the periphery of the plurality of electric wires 3. The core material 2 with elasticity has a core material body 21 harder than the electric wires 3, and a covering layer 22 disposed in the outer periphery of the core material body 21, and covering the core material body 21.SELECTED DRAWING: Figure 1

Description

The present invention relates to cables.

In recent years, a SCARA robot (horizontal multi-joint robot) in which an arm moves horizontally has been widely used as an industrial robot used in factories and the like. In a SCARA robot, a cable is often provided in a state in which it is bent in an arch shape over a movable portion from a tip end portion to a base end portion of an arm.

As prior art document information related to the invention of this application, there is Patent Document 1.

Japanese Patent No. 4979075

In the above-mentioned SCARA robot or the like, when the arm moves at high speed, the arched cable swings due to the operation. As the high speed operation of the arm is repeatedly performed, the cable repeatedly swings at a high speed. A stress is applied to the oscillating cable in the oscillating direction of the cable, but the cable is unable to withstand the stress and vibrates significantly, causing the cable to oscillate following the high-speed operation of the arm. There is a problem that the cable disappears and a breakage of the cable easily occurs at the terminal portion of the cable where stress is concentrated.

It may be possible to increase the size of the bush covering the cable around the end of the cable in order to prevent disconnection at the end of the cable, but in this case it is necessary to secure a space for arranging the bush, and design restrictions apply. May occur, or the flexible movement of the cable when the cable follows the high-speed operation of the arm may decrease.

Therefore, it is an object of the present invention to provide a cable which is less likely to be shaken by the swing generated by the high-speed operation of the movable part and which is less likely to be broken even when the movable part is wired in an arch shape.

The present invention, for the purpose of solving the above problems, a core material made of resin provided in the center of the cable, a plurality of electric wires spirally twisted around the outer periphery of the core material, and the periphery of the plurality of electric wires And a sheath provided so as to collectively cover the core member, the core member having elasticity and being harder than the electric wire, and a core member provided on an outer periphery of the core member. A coating layer, which covers the material body, is provided.

According to the present invention, it is possible to provide a cable which is less likely to be shaken by the swing generated by the high-speed operation of the movable part and which is less likely to be broken even when the movable part is wired in an arch shape.

It is sectional drawing which shows the cross section perpendicular|vertical to the longitudinal direction of the cable which concerns on one embodiment of this invention.

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

FIG. 1 is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of the cable according to the present embodiment. In an industrial robot such as a SCARA robot, the cable 1 is arranged in a state of being bent in an arch shape over a movable portion such as an arm joint.

As shown in FIG. 1, a cable 1 includes a core material 2 made of a resin provided in the center of the cable, a plurality of electric wires 3 spirally twisted around the outer periphery of the core material 2, and a plurality of electric wires 3 around the electric wire 3. And a sheath 4 provided so as to collectively cover.

The plurality of electric wires 3 include a power supply line 5 for power supply and a signal line 6 for signal transmission. Here, a case will be described where the plurality of electric wires 3 include two power supply lines 5 and one signal line 6, but the number of the power supply lines 5 and the signal lines 6 is not limited to this, and the power supply line 5 is not limited thereto. The electric wire 3 other than the signal line 6 may be included.

The power supply line 5 includes ETFE (tetrafluoroethylene-ethylene copolymer) on the outer periphery of a stranded wire conductor 51a formed by twisting together strands of an electric conductor such as copper (for example, strands having an outer diameter of 0.12 mm or less). ), FEP (tetrafluoroethylene-hexafluoropropylene copolymer), PFA (tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer), or the like, and a plurality of insulated electric wires 51 coated with an insulator 51b made of a fluororesin. A press winding tape 53 that is spirally wound around the outer circumference of an assembly 52 in which a plurality of insulated electric wires 51 are twisted together, and a first inside that is provided on the outer circumference of the press winding tape 53 and covers the assembly 52 collectively. And a sheath 54. As the press-winding tape 53, a paper tape or a tape made of non-woven fabric can be used. The first inner sheath 54 may be made of polyvinyl chloride (PVC) resin, for example.

In the present embodiment, an interposition 55 is provided in the center of the power supply line 5, five insulated electric wires 51 are spirally wound around the interposition 55, and ten insulated electric wires 51 are spirally wound around the outer periphery thereof. By winding, the assembly 52 was configured using a total of 15 insulated electric wires 51. Note that the number of insulated electric wires 51 forming the aggregate 52 is not limited to this. As the interposition 55, for example, a thread-shaped body or a band-shaped body made of a string, paper, non-woven fabric, or the like can be used. Here, a staple yarn is used as the interposition 55. The interposition 55 is provided so as to fill the gap existing between the five insulated electric wires 51 provided inside the power supply line 5 in the radial direction.

The signal line 6 transmits a control signal used for controlling various devices such as control of an air injector. The signal line 6 includes a twisted pair wire assembly 62 in which a plurality of twisted wires 61 for signal transmission are twisted together, a holding tape 63 wound around the twisted wire assembly 62 in a spiral shape, and a holding wire 63. It has a shield layer 64 provided so as to cover the periphery of the winding tape 53, and a second inner sheath 65 provided on the outer periphery of the shield layer 64 and collectively covering the twisted wire assembly 62.

The twisted pair wire 61 includes ETFE (tetrafluoroethylene-ethylene co-weight) around a twisted wire conductor 611a formed by twisting wires (for example, wires having an outer diameter of 0.12 mm or less) made of an electric conductor such as copper. Union), FEP (tetrafluoroethylene-hexafluoropropylene copolymer), PFA (tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer), and the like. It is configured. Here, five twisted pair wires 61 and the interposition 66 are twisted together to form a twisted pair wire assembly 62. The number of twisted pair wires 61 forming the twisted pair wire assembly 62 is not limited to this. As the interposition 66, a thread-shaped body or a band-shaped body made of a string, paper, non-woven fabric, or the like can be used. Here, a staple yarn is used as the interposition 66. The interposition 66 is provided so as to fill the gap that exists between the five twisted pair wires 61 and the press-winding tape 63 that covers these five twisted wires 61.

Each of the plurality of twisted pair wires 61 forming the twisted pair wire assembly 62 is configured to have a different twist pitch. This is to suppress crosstalk (noise) between the twisted pair wires 61. The twist pitch of the twisted pair wire 61 is the distance along the longitudinal direction of the twisted pair wire 61 at the point where the insulated wire 611 is at the same position in the circumferential direction of the twisted pair wire 61.

In the present embodiment, the twisting direction of the twisted wire conductor 611a in each insulated electric wire 611 and the twisting direction of the twisted pair wire 61 are opposite to each other, and the twisting direction of the twisted pair wire 61 and the twisted pair wire assembly. The twist direction of 62 is the opposite direction. The twisting direction of the twisted wire conductor 611a is the same as the twisting direction of the twisted pair wire assembly 62. When the twisting direction of the twisted pair wire 61 is the same as the twisting direction of the twisted wire conductor 611a and the twisted pair wire assembly 62, twisting in the same direction is repeatedly applied to the strands of the twisted wire conductor 611a. This is because there is a possibility that the wire may be drawn out when it is bent. By setting the twisting direction of the twisted pair wire 61 to be opposite to the twisting direction of the twisted wire conductor 611a or the twisted wire bundle 62, it is possible to suppress disconnection of the strands and improve resistance to bending. ..

The twisting direction of the stranded wire conductor 611a is the direction in which the strand of wire is rotating from the other end side to the one end side when viewed from the one end side of the insulated wire 611. The twist direction of the twisted pair wire 61 is the direction in which the insulated wire 611 rotates from the other end side to the one end side when viewed from one end side of the twisted pair wire 61. The twist direction of the twisted pair wire assembly 62 is the direction in which the twisted pair wire 61 rotates from the other end side to the one end side when viewed from one end side of the twisted pair wire assembly 62.

As the press-winding tape 63, a paper tape or a tape made of non-woven fabric can be used. The shield layer 64 is composed of a braided shield in which metal wires are woven. A drain wire 67 used for grounding the shield layer 64 is provided between the shield layer 64 and the press-winding tape 63. As the second inner sheath 65, for example, one made of polyvinyl chloride (PVC) resin can be used.

The outer diameters of the three electric wires 3, that is, the two power supply wires 5 and the single signal wire 6 are substantially equal (for example, 80% or more of the outer diameter of the thickest electric wire 3). It is adjusted appropriately. The outer diameter of each electric wire 3 can be adjusted by the thickness of the first inner sheath 54 and the second inner sheath 65. The outer diameter of each electric wire 3 is preferably larger than the outer diameter of the core material 2 described later, and can be set to about 6 mm to 8 mm, for example.

The cable 1 has one or more air tubes 7 for passing air. The air tube 7 is used, for example, for supplying air to an air injector, and is made of urethane resin or the like. The air tube 7 is formed in a hollow cylindrical shape having a hollow portion 71 along the longitudinal direction thereof, and has an outer diameter smaller than that of the electric wire 3 (the power supply line 5 and the signal line 6). Here, a case will be described in which the same number of air tubes 7 as the electric wires 3 is used, but the number of air tubes 7 to be used is not limited to this.

The three electric wires 3 and the three air tubes 7 are alternately arranged in the cable circumferential direction, and the three electric wires 3 and the three air tubes 7 are spirally arranged on the outer periphery of the core material 2. Are twisted together. It is desirable that the electric wires 3 and the air tubes 7 are arranged as evenly (at equal intervals) as possible in the circumferential direction of the cable in order to suppress a problem such as a bias in twisting.

A press-winding tape 8 is spirally wound around the three twisted wires 3 and the three air tubes 7. As the press-winding tape 8, a paper tape or a tape made of non-woven fabric can be used. A sheath 4 is provided on the outer circumference of the press-winding tape 8. As the sheath 4, for example, one made of polyvinyl chloride (PVC) resin can be used. The thickness of the sheath 4 is preferably thicker than the thickness of the first inner sheath 54 and the second inner sheath 65 of each electric wire 3, and can be, for example, about 1.4 mm to 1.8 mm.

In the cable 1, all the electric wires 3 are in contact with the inner peripheral surface of the press winding tape 8. Moreover, the electric wire 3 and the air tube 7 which are adjacent to each other in the circumferential direction are in contact with each other. Further, each electric wire 3 is in contact with the core material 2, and each air tube 7 is not in contact with the core material 2.

Further, in the present embodiment, the wire 9 and the air tube 7 as well as the interposition 9 are twisted around the outer periphery of the core material 2, and the press-winding tape 8 is wound around it. As the interposition 9, it is also possible to use a thread-shaped body or a strip-shaped body made of a string, paper, non-woven fabric, or the like. Here, a staple yarn is used as the interposition 9. The interposition 9 is provided so as to fill the gap existing between the core material 2, the electric wire 3, the air tube 7, and the press-winding tape 8 covering these.

(Explanation of the core material 2)
In the cable 1 according to the present embodiment, the core material 2 made of resin is arranged at the center of the cable. The core material 2 imparts rigidity to the cable 1, and the cable 1 is largely shaken even when it is shaken left and right (when it is swung) in a state of being bent and arranged in an arch shape. Play the role of suppressing.

The core material 2 has a core material main body 21 and a coating layer 22 that is provided on the outer periphery of the core material main body 21 and covers the core material main body 21.

The core body 21 is made of a resin that has elasticity and is harder than the electric wire 3 (having low flexibility and being difficult to bend). That is, the core body 21 is made of a resin member that has a restoring force that tends to return to a straight line when bent, and the restoring force is larger than the restoring force of the electric wire 3. In the present embodiment, the core body 21 made of nylon is used. The core body 21 is preferably made of a resin that is harder than the coating layer 22 (harder than the coating layer 22 when the hardnesses indicated by Rockwell hardness and Shore hardness are compared).

The coating layer 22 is for further improving the restoring force of the core material 2 while maintaining the restoring force of the core material body 21 described above (without reducing the restoring force of the core material body 21). The coating layer 22 is also for protecting the core body 21. In order to avoid increasing the diameter of the cable 1, it is desirable that the coating layer 22 be as thin as possible. Specifically, the thickness of the coating layer 22 may be smaller than the thickness of the core material body 21 (radius when the core material body 21 is not hollow but solid). The coating layer 22 is provided on the outer periphery of the core body 21 by coating the outer periphery of the core body 21 with a resin by tube extrusion. When the cable 1 moves following the high-speed operation of the movable part, the coating layer 22 is formed on the surface of the core body 21 so that the core body 21 and the coating layer 22 move integrally. It is preferable that the contact portion is in close contact with the core body 21. In particular, it is preferable that the coating layer 22 is in close contact with the surface of the core body 21 so as to be integrated with the core body 21.

With the core member 2 having such a structure, when the cable 1 is bent and arranged in an arch shape, the restoring force of the core member main body 21 to return to the linear shape is used as the base of the restoring force of the core member 2. Since the coating layer 22 acts so as to supplement the restoring force of the core body 21, it is possible to give the restoring force to the core 2 so that the wiring shape of the cable 1 is maintained. As a result, even when the cable 1 is arranged in an arch shape over a movable portion such as an arm, a change in the wiring shape of the cable 1 that swings following the high-speed operation of the movable portion is suppressed, and Since it is possible to withstand the stress applied to the swinging direction, the cable 1 is less likely to be shaken greatly. As a result, the cable 1 can be repeatedly swung following the high-speed operation of the movable part, and the stress applied to the end portion of the cable 1 is suppressed, so that disconnection is less likely to occur. In order to further suppress the deflection of the cable 1, it is desirable that the end portion of the core material 2 be firmly fixed to a device such as a SCARA robot at the end portion of the cable 1. Further, by using the core material 2 as described above, the cable follows the high-speed operation of the arm even when a member having a large restoring force that returns to the linear shape is used as the core material body 21. It is possible to make it difficult to reduce the flexible movement of the cable.

In addition, the core body 21 is preferably formed in a hollow cylindrical shape (that is, a tube shape) having a hollow portion 21a along the longitudinal direction. This makes it possible to reduce the weight of the core material 2 and prevent the cable 1 from being easily shaken when swinging due to an increase in weight. Further, by forming the core material main body 21 in the shape of a hollow cylinder, it is possible to release stress due to bending by deformation of the core material main body 21, and in comparison with the case where the core material main body 21 has a solid columnar shape, The core body 21 is less likely to be broken.

The inner diameter and the outer diameter of the core material body 21 are appropriately set within a range in which the outer diameter of the core material 2 is smaller than the outer diameter of the electric wires 3 and the air tubes 7 depending on the thickness and the number of the electric wires 3 and the air tubes 7 to be used. You can set it to any value. Here, the inner diameter of the core body 21 was 4 mm, the outer diameter was 6 mm, and the thickness of the core body 21 was 1 mm. When the core body 21 made of nylon is used, the outer diameter is preferably 6 mm or less in order to maintain the bendability (flexibility) of the cable 1.

In the present embodiment, the coating layer 22 is a wear suppressing layer 22a for suppressing friction between the electric wire 3 and the core body 21. The wear suppressing layer 22a is for suppressing the occurrence of wear due to friction between the core body 21 made of nylon and each electric wire 3.

The wear suppressing layer 22a is preferably made of a resin having a small coefficient of friction on the surface, good slippage, and resistant to cracking and peeling due to bending. In the present embodiment, the wear suppressing layer 22a is made of a resin containing fluororubber and fluororesin. When a fluorine resin containing no rubber component is used as the wear suppressing layer 22a, cracks are likely to occur during bending.

As the resin containing fluororubber and fluororesin, one containing fluororubber and fluororesin in a mass ratio of 95:5 to 20:80 may be used. Further, the fluororesin preferably contains polytetrafluoroethylene and the meltable fluororesin in a mass ratio of 99.5:0.5 to 75:25. Examples of the resin satisfying these mass ratios include Daier (registered trademark) fluoro TPV manufactured by Daikin Industries, Ltd. By using this resin, the wear suppressing layer 22a having both the wear resistance and low dust generation of the fluororesin and the flexibility and elasticity of the fluororubber (the elasticity improves the straightness when U-shaped is bent). Can be formed.

By providing the wear suppressing layer 22a, it is possible to suppress wear of the core body 21 and the sheaths (the first inner sheath 54 and the second inner sheath 65) of the electric wire 3 and realize the long-life cable 1. The thickness of the wear suppressing layer 22a is, for example, 0.2 mm or more and 0.5 mm or less. Here, the thickness of the wear suppressing layer 22a is 0.25 mm. The core body 21 is harder than the wear suppressing layer 22a and thicker than the wear suppressing layer 22a.

(Operation and Effect of Embodiment)
As described above, in the cable 1 according to this embodiment, the core material 2 made of resin provided in the center of the cable, the plurality of electric wires 3 spirally twisted around the outer periphery of the core material 2, and the plurality of electric wires 3 A sheath 4 provided so as to collectively cover the periphery of the electric wire 3, the core material 2 having elasticity and being harder than the electric wire 3, and an outer periphery of the core body 21. And a coating layer 22 that covers the core body 21.

By providing the core material 2, when the cable 1 is bent and arranged in an arch shape, the shape of the cable 1 can be maintained by the force of the core material 2 to return to the linear shape. As a result, in a SCARA robot or the like, when wiring is performed in an arch shape over the movable part such as an arm, even if the movable part is operated at high speed, it is difficult to shake due to the swing and a disconnection occurs. The cable 1 that is difficult to perform can be realized.

Note that, for example, it is conceivable to increase the outer diameter of the cable to suppress disconnection of the terminal portion, but in this case, the mass of the cable becomes large, and it becomes difficult to follow the high-speed operation of the movable portion such as the arm. According to the present embodiment, it is possible to realize the cable 1 that is hard to break without increasing the outer diameter or the mass, and the followability to high-speed operation is high.

(Summary of Embodiments)
Next, the technical idea grasped from the above-described embodiment will be described with reference to the reference numerals and the like in the embodiment. However, each symbol and the like in the following description is not intended to limit the constituent elements in the claims to the members and the like specifically shown in the embodiments.

[1] A core material (2) made of resin provided at the center of the cable, a plurality of electric wires (3) spirally twisted around the outer periphery of the core material (2), and a plurality of the electric wires (3). A sheath (4) provided so as to cover the surroundings collectively, the core material (2), the core material (2) has elasticity, and more than the electric wire (3). A cable (1) having a hard core body (21) and a coating layer (22) provided on the outer periphery of the core body (21) and covering the core body (21).

[2] The cable (1) according to [1], wherein the core material body (21) is harder than the coating layer (22).

[3] The cable (1) according to [1] or [2], wherein the outer diameter of the core material (2) is smaller than the outer diameter of the electric wire (3).

[4] The coating layer (22) is a wear suppressing layer for suppressing friction between the electric wire (3) and the core body (21), and the coating layer (22) is any one of [1] to [3]. Cable (1) as described in 1.

[5] The cable according to any one of [1] to [4], wherein the core material main body (21) is formed in a hollow cylindrical shape having a hollow portion (21a) along a longitudinal direction. 1).

[6] The cable (1) according to [5], wherein the thickness of the coating layer (22) is smaller than the thickness of the core material body.

[7] The cable (1) according to any one of [1] to [6], wherein the core body (21) is made of nylon.

[8] The cable (1) according to any one of [1] to [7], wherein the coating layer (22) is made of an insulating material containing fluororubber and fluororesin.

[9] It has one or more air tubes (7) for passing air, and the plurality of electric wires (3) and the air tubes (7) are spirally twisted around the outer periphery of the core material (2). The cable (1) according to any one of [1] to [8], which is combined.

[10] The electric wire (3) includes an aggregate (52) formed by twisting a plurality of insulated electric wires (51) for power supply, and a first inner sheath (54) that collectively covers the aggregate (52). The cable (1) according to any one of [1] to [9], which includes a power supply line (5) having (1).

[11] The electric wire (3) collectively covers a twisted pair wire assembly (62) obtained by twisting a plurality of twisted wire pairs (61) for signal transmission, and a twisted wire wire assembly (62). The cable (1) according to any one of [1] to [10], including a signal line (6) having a second inner sheath (65).

Although the embodiment of the invention has been described above, the embodiment described above does not limit the invention according to the claims. It should be noted that not all combinations of the features described in the embodiments are essential to the means for solving the problems of the invention. Further, the present invention can be appropriately modified and implemented without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1... Cable 2... Core material 21... Core material main body 21a... Hollow part 22... Coating layer 22a... Wear suppression layer 3... Electric wire 4... Sheath 5... Power supply wire 51... Insulated electric wire 52... Assembly 54... 1st inner sheath 6 ... signal wire 61... twisted wire 62... twisted wire assembly 65... second inner sheath 7... air tube 71... hollow portion

The present invention, for the purpose of solving the above problems, a core material made of resin provided in the center of the cable, a plurality of electric wires spirally twisted around the outer periphery of the core material, and the periphery of the plurality of electric wires And a sheath provided so as to collectively cover the core material, the core material having elasticity and being harder than the electric wire, and the core material body on the outer periphery of the core material body. It provided in close contact to move together, have a, and a covering layer covering the core body, the core material body is constituted by a hard resin than the resin constituting the coating layer, in the longitudinal direction Provided is a cable, which is formed in a hollow cylindrical shape having a hollow portion along it .

Claims (11)

A core material made of resin provided in the center of the cable,
A plurality of electric wires spirally twisted around the outer periphery of the core material,
A sheath provided so as to collectively cover the periphery of the plurality of electric wires,
The core material has elasticity, and has a core material body that is harder than the electric wire, and a coating layer that is provided on the outer periphery of the core material body and covers the core material body.
cable. The core body is harder than the hardness of the coating layer,
The cable according to claim 1. The outer diameter of the core material is smaller than the outer diameter of the electric wire,
The cable according to claim 1 or 2. The coating layer is a wear suppressing layer for suppressing friction between the electric wire and the core material body,
The cable according to any one of claims 1 to 3. The core material main body is formed in a hollow cylindrical shape having a hollow portion along the longitudinal direction,
The cable according to any one of claims 1 to 4. The thickness of the coating layer is smaller than the thickness of the core body,
The cable according to claim 5. The core body is made of nylon,
The cable according to any one of claims 1 to 6. The coating layer is made of an insulating material containing fluororubber and fluororesin,
The cable according to any one of claims 1 to 7. Having one or more air tubes for passing air,
The plurality of electric wires and the air tube are helically twisted around the outer periphery of the core material,
The cable according to any one of claims 1 to 8. The electric wire includes an assembly formed by twisting a plurality of insulated electric wires for power supply, and a power supply wire having a first inner sheath that collectively covers the assembly.
The cable according to any one of claims 1 to 9. The electric wire includes a paired twisted wire assembly formed by twisting a plurality of paired twisted wires for signal transmission, and a signal wire having a second inner sheath that collectively covers the paired twisted wire assembly,
The cable according to any one of claims 1 to 10.

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