JP4628758B2 - Welding robot - Google Patents

Description

  The present invention relates to an improvement in the mounting structure of a power supply cable or the like for reducing a load applied to a one-wire power cable connected to a welding torch of a welding robot.

Today, in order to improve the work efficiency of welding, it is widely performed to automate welding using a welding robot. FIG. 6 is a diagram showing a general configuration of a welding robot when an articulated robot is used.
In the figure, a welding torch 3 is attached to the tip of a wrist 2 of a manipulator 1, and a welding wire 5 wound around a wire reel 4 is welded by a wire feeder 6 attached to the manipulator 1. 3 is sent. Further, electric power is supplied from the welding power source device 7 to the welding torch 3, and gas is supplied from the gas cylinder 38 to the welding torch 3. A command signal is input from the teach pendant 8 to the robot controller 9, and a signal from the robot controller 9 is input to the manipulator 1 to rotate the six axes including the first to sixth axes for welding. The tip position of the torch 3 is controlled. (For example, refer to Patent Document 1).

[Prior art 1]
Conventionally, the attachment structure of the welding torch 3 and the wire feeder 6 at the tip 2 of the wrist of the manipulator 1 is the structure shown in FIG. FIG. 7 is a view showing a mounting structure of the welding torch 3 and the wire feeder 6 at the tip of the wrist 2 of the manipulator 1 of the prior art 1. In the figure, the wire reel 4 is attached to the manipulator 1, and the wire feeder 6 is attached on the upper arm 10 of the manipulator 1. The welding torch 3 is attached to the wrist 2 by a connecting member 11.
The welding wire wound around the wire reel 4 is sent out by the wire feeder 6 and travels through the center of the one-wire power cable 12 for supplying electric power and gas in an integrated manner. To be supplied.
The first axis J1 to the sixth axis J6 are provided, and the tip position and posture of the welding torch 3 can be changed by turning, swinging, or rotating as indicated by arrows.

  The one-wire power cable 12 is provided with a coil liner for guiding a welding wire at the center, and a hose for flowing gas on the outer periphery thereof. And the outer periphery of this hose is covered with a conductive wire for supplying electric power, and the outermost periphery is covered with insulation. Thus, since the one-wire power cable 12 has a multiple structure, it has a high bending rigidity and is difficult to bend. Therefore, in order to reduce the drag when the welding torch 3 moves, the length is slackened. That is, even if the cable 12 is provided in a space outside the upper arm 10 from the wire feeder 6 to the welding torch 3 in order to enable the deformation of the cable 12, even if the welding torch 3 operates, The complicated deformation of each time is allowed to some extent.

  Moreover, when operating the manipulator 1 over the maximum range, the cable length is set so that no load is applied to the one-wire power cable 12. In addition, the cable 12 can be changed to an optimum length while taking into consideration the influence on the welding posture, the interference with the jig, the feedability of the welding wire, etc. without reducing the durability of the cable 12. Is possible.

In FIG. 7, when the manipulator 1 is operated to rotate the sixth axis J6, the one-wire power cable 12 hits the wrist 2 of the manipulator 1, and the sixth axis J6 cannot be rotated any further. The shaded portion shown in FIG. Therefore, for example, when welding the circumference of a workpiece to be welded with a constant tip angle of the welding torch 3 with respect to the workpiece, the one-line power cable 12 hits the wrist 2 and the sixth axis J6 cannot be rotated. For this reason, a portion where welding cannot be performed must be stopped by stopping welding, changing the tip angle of the welding torch 3 and changing the welding current value, welding voltage value, and welding speed corresponding to the tip angle. I must.
In addition, when the circumference of the workpiece is subjected to multi-layer welding, since the one-wire power cable 12 hits the wrist 2 of the manipulator 1 and the sixth axis J6 cannot be rotated any more, a seamless weld bead Can not be formed.

[Prior Art 2]
In order to solve the problem that the one-line power cable 12 interferes with the wrist 2 of the manipulator 1 when the manipulator 1 is operated and the sixth axis J6 is rotated in the related art 1 described above, FIG. A wiring structure of the one-wire power cable 12 shown in FIG. 9 has been proposed. FIG. 8 is a view showing a manipulator of a welding robot according to prior art 2, and FIG. 9 is a view for explaining the structure of a fixed feeding member of the welding robot according to prior art 2.

In FIG. 8, a turning base 14 is mounted on the base 13 and turns around the first axis J1. A lower arm 15 is mounted on the turning base 14 and swings around the second axis J2. An upper arm 16 is attached to the upper end of the lower arm 15 and swings about the third axis J3. A body 17 is attached to the tip of the upper arm 16, and the body 17 rotates around a fourth axis J <b> 4 (a wrist first axis) in the longitudinal direction of the upper arm 16. An oscillating body 19 is attached to the tip of the body 17 and oscillates around a fifth axis J5 (wrist second axis) orthogonal to the fourth axis J4 (wrist first axis). A rotating body 20 is attached to the tip of the oscillating body 19 and rotates about a sixth axis J6 (wrist third axis) orthogonal to the fifth axis J5 (wrist second axis). A welding torch 3 is attached to the rotating body 20.
The first axis J1 to the sixth axis J6 are provided with a motor via a speed reducer, and are driven by inputting a command from the robot control device 9 shown in FIG.

  The wire feeder 6 is attached to a swing base 21 that swings at the upper end of the lower arm 15 shown in FIG. 8, and the base end portion of the upper arm 16 is rotatably supported by the swing base 21. ing. A wire for welding is sent from the wire feeder 16 substantially parallel to the fourth axis J4 (wrist first axis). The upper arm 16 is operated by a motor 23 via a speed reducer 22.

  In FIG. 9, a fixed power supply member 24 is provided between the upper arm 16 and the wire feeder 6, and a power supply cable 25 and a gas hose 26 are connected to the outer peripheral surface of the fixed power supply member 24. An insertion hole for a welding wire is formed in the central axis of the fixed power supply member 24.

The body 17 is provided with a support member 27. A surface of the support member 27 is perpendicular to the fourth axis J4 (wrist first axis), and an insertion hole 18 for the one-line power cable 12 is formed. The insertion hole 18 is formed at a position offset upward from the fourth axis J4 (wrist first axis).
In the one-wire power cable 12, the welding wire advances in the center, and power and gas are supplied together. The proximal end portion of the one-wire power cable 12 is connected to the distal end portion of the fixed feeding member 24, and the cable 12 passes through the insertion hole 18 of the upper arm 16 and the trunk 17 and extends in the longitudinal direction of the trunk 17 to be welded. It is connected to the for torch 3.
The front end side of the body 17 is offset laterally from the fourth axis J4 (the wrist first axis), and the swing body 19 supports the rotating body 20 in a cantilever manner. For this reason, the one-wire power cable 12 can run along the longitudinal direction of the body 17 in the body 17 and in the adjacent space.

As described above, in the welding robot of the prior art 2 shown in FIG. 8, the single-wire power cable 12 passes through the insertion hole 18 of the upper arm 16 and the trunk 17 and extends in the longitudinal direction of the trunk 17 to perform welding. It is connected to the for torch 3. Therefore, when the manipulator 1 is operated, it is possible to reduce the interference of the one-wire power cable 12 with the body 17, the work piece, the jig, or the like, so that the manipulator 1 can be operated freely. The optimal welding torch posture can be taken.
However, it has the problems described later.
JP 2003-94168 A

  In the welding robot of prior art 2, the length of the one-line power cable 12 when the fourth axis J4 and the fifth axis J5 are in a straight line is the optimum cable length because of the structure. This flow becomes a fixed length when a welding robot is used. Therefore, although interference with the trunk | drum 17, a to-be-welded object, a jig | tool, etc. can be avoided, since the length of the cable 12 cannot be provided, the one-wire type power cable 12 generated when the manipulator 1 is operated. The external force applied directly to the cable 12 could not be avoided.

  For this reason, a one-wire power cable 12 with improved durability is used. However, since a considerable load is applied, the replacement cycle is fast, resulting in cost and man-hours for replacement, and work efficiency. There was a problem that decreased.

  Therefore, in order to reduce the load applied to the cable 12 as much as possible in order to ensure the durability of the one-wire power cable 12 and the feedability of the welding wire, it is necessary to limit the operating range and operating speed of the manipulator 1. there were.

Further, when the sixth axis J6 of the manipulator 1 is rotated, the one-wire power cable 12 is twisted and the welding wire fed to the welding torch 3 is easily twisted, and the tip end position of the wire matches the desired welding target position. I can't let you. As a result, a uniform and beautiful weld bead appearance cannot be obtained.
If the welding wire is easily twisted, the contact point between the welding wire and the power feed tip attached to the tip of the welding torch 3 is not constant. As a result, the wire protrusion length, which is the length from the contact point between the welding wire and the power feed tip to the tip of the wire, is not constant, so that the amount of melting of the wire is not constant and the penetration shape is made uniform. I can't.

  The present invention improves the durability of a one-wire power cable, reduces the twist of the welding wire, improves the quality of the welding result, expands the operating range and operating speed of the manipulator, and has a complicated shape It aims at providing the robot for welding which can improve the adaptability to a to-be-welded object.

In order to achieve the above object, the first invention provides:
An upper arm with an insertion hole for a one-wire power cable;
A body that is attached to the distal end portion of the upper arm and has an insertion hole for the one-wire power cable formed at the proximal end portion thereof and rotates around the wrist first axis in the longitudinal direction of the upper arm;
An oscillating body attached to the tip of the body and oscillating about a wrist second axis perpendicular to the wrist first axis;
A rotating body attached to the tip of the swinging body and rotating around a wrist third axis orthogonal to the wrist second axis;
A welding torch attached to the rotating body;
A wire feeder attached to the base end of the upper arm and delivering a welding wire substantially parallel to the wrist first axis;
A conductive power supply member provided between the upper arm and the wire feeder, wherein a power supply cable and a gas hose are connected to an outer peripheral surface, and an insertion hole of the welding wire is formed in a central axis;
The welding wire, which is connected to the distal end portion of the power supply member, passes through the upper arm and the insertion hole of the body, extends in the longitudinal direction of the body and travels through the center, and power and gas are integrated. In the welding robot provided with the one-line power cable to be supplied to the torch for operation,
A guide adapter fixed to the welding wire delivery port of the wire feeder and fed with the welding wire;
Before Symbol proximal end portion of the sheet collecting member is rotatably mounted on the distal end of the guide adapter,
Connecting the power supply cable and the gas hose by forming a slack wound around the outer periphery of the power supply member at a predetermined winding radius and number of turns depending on the material and shape of the power supply cable;
The welding robot , wherein the winding radius decreases or increases when the power feeding member rotates together with the power feeding cable and the gas hose .

  The welding robot according to the present invention includes an upper arm in which an insertion hole for a one-wire power cable is formed, and an upper hole that is attached to a distal end portion of the upper arm and has an insertion hole for the one-wire power cable in a base end portion. A torso that rotates about the wrist first axis in the longitudinal direction of the arm, an oscillating body that is attached to the tip of the torso and swings about the wrist second axis that is orthogonal to the wrist first axis, and the tip of the oscillating body A rotating body that is attached to the rotating portion and rotates around the third wrist axis orthogonal to the wrist second axis, a welding torch attached to the rotating body, and a welding wire attached to the base end of the upper arm. A wire feeder that feeds substantially parallel to the wrist first axis, a feeding cable and a gas hose are connected to the outer peripheral surface, and an insertion hole for a welding wire is formed in the central axis, so that the upper arm and the wire feeder Conductive power supply member provided between the power supply unit and the power supply unit A single-line power that is connected to the tip of the upper arm and passes through the upper arm and the through hole of the fuselage, extends in the longitudinal direction of the fuselage and travels through the center, and power and gas are supplied together to the welding torch. And a base end portion of the power supply member is rotatably attached to the welding wire delivery port of the wire feeder, and the power supply cable and the gas hose are preliminarily disposed in the vicinity of the connection portion with the power supply member depending on the material and shape of the power supply cable. It winds around the outer periphery of the power feeding member with a predetermined winding radius and number of windings to form a slack, and is connected to the outer peripheral surface of the power feeding member.

As a result, when the manipulator 1 is operated, the load of the rotational force applied to the one-wire power cable 12 can be reduced, so that the durability of the one-wire power cable 12 can be improved. Furthermore, twisting of the welding wire is reduced, and the welding wire can be stably fed, and the quality of the welding result can be improved.
Further, unlike the prior art 2, there is no need to limit the operating range and operating speed of the manipulator 1 in order to reduce the load applied to the one-wire power cable 12, so that the operating range and operating speed of the manipulator 1 are expanded. Therefore, adaptability to a workpiece having a complicated shape can be improved.
Further, since the twist of the one-wire power cable 12 when the manipulator 1 is operated can be suppressed, it is not necessary to consider the length of contraction due to the twist when the cable 12 is connected, and workability is improved. Can do. Moreover, since the slack which arises by considering the length which shrink | contracts by a twist can be eliminated, the fall of the feedability of the welding wire which arises by this slack can be prevented.

[Embodiment 1]
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described based on examples with reference to the drawings.
FIG. 1 is a view showing a manipulator of a welding robot according to the present invention, FIG. 2 is a view for explaining the structure of a rotating power supply member of the welding robot according to the present invention, and FIG. FIG.
In FIG. 1, a rotary power supply member 28 is provided between the upper arm 16 and the wire feeder 6, and a power supply cable 29 and a gas hose 30 are connected to the outer peripheral surface of the rotary power supply member 28. 1 and 2, the same reference numerals are given to the same functions as those of the prior art 2 shown in FIGS. 8 and 9, and the description thereof is omitted.

Hereinafter, the structure of the rotary feeding member 28 of the present invention will be described in detail.
In FIG. 3, a bush 31 is fitted into the proximal end portion of the rotary power feeding member 28, and a guide adapter 32 is inserted into the bush 31. The guide adapter 32 is inserted into the welding wire delivery port 6a of the wire feeder 6 (see FIG. 2), and the slip ring 33 is inserted into the guide adapter 32 and the welding wire delivery port 6a to guide the guide. An adapter 32 is fixed to the wire feeder 6.
As a result, the rotary power supply member 28 fitted with the bush 31 is rotatably attached around the guide adapter 32. The bush 31 may be provided with a bearing to improve the rotational performance.

An inlet guide 34 is provided in the guide adapter 32 shown in FIG. 3, and this inlet guide 34 is connected to a coil liner 35 of the one-wire power cable 12 inserted in the rotary power feeding member 28. By these inlet guide 34 and coil liner 35, the welding wire is fed to the welding torch 3.
As shown in FIG. 2, the power supply cable 29 and the gas hose 30 are wound around the rotary power supply member 28 and connected to the power supply cable connection portion 36 and the gas hose connection portion 37 shown in FIG. 3, respectively. Since the rotary power supply member 28 has conductivity, the power supplied from the power supply cable 29 flows through the rotary power supply member 28 and is supplied to the one-wire power cable 12. Further, the gas from the gas hose 30 flows through the rotary power feeding member 28 and is supplied to the one-wire power cable 12.

  FIG. 4 is a diagram for explaining a connection state of the power supply cable 29 of the welding robot of the present invention to the rotary power supply member 28, and FIG. It is a figure when the connection state of is seen from the wire feeder side.

The feeding cable 29 is connected to the feeding cable coupling portion 36 of the rotary feeding member 28 by providing a slack in the vicinity of the coupling portion with the rotary feeding member 28. When there is sufficient slack in the power supply cable 29 before the manipulator 1 operates, the power supply cable 29 is located near the connecting portion with the rotary power supply member 28 as shown in 29a of FIG. 4 (A) and FIG. There is sagging.
Then, when the manipulator 1 operates and a rotational force is applied to the one-wire power cable 12 and the rotary power feeding member 28 connected to the power cable 12 rotates, the state shown in 29B of FIG. 4B and FIG. As shown, the sag in the vicinity of the connecting portion is reduced, so that the pulling force applied to the power supply cable 29 is suppressed.

This sagging is formed by winding and connecting to the outer peripheral surface of the rotary power supply member 28 with a winding radius and the number of turns predetermined by the material and shape of the power supply cable 29.
4 and 5 show only the power supply cable 29, the gas hose 30 is also connected to the rotary power supply member 28 in the same connection state.

  The feeding cable 29 and the gas hose 30 are subjected to bending load to some extent as the rotating feeding member 28 rotates. Therefore, the feeder cable 29 uses a durable strand wire, and the gas hose 30 uses a soft soft nylon tube.

The operation will be described below.
In FIG. 1, when the manipulator 1 is operated, the fourth axis J4 (wrist first axis), the fifth axis J5 (wrist second axis), and the sixth axis J6 (wrist third axis) are rotated, so that A rotational force acts on the power cable 12. As a result, the rotary power supply member 28 connected to the one-wire power cable 12 also rotates. At this time, when the rotary power supply member 28 rotates from the direction shown in FIG. 4A to the direction shown in FIG. 4B, the winding radius of the power supply cable 29 and the gas hose 30 connected to the rotary power supply member 28 decreases. The sagging is reduced, and the pulling force acting on the power supply cable and the gas hose is suppressed.
Further, when the rotary power feeding member 28 rotates in the opposite direction, the tensile force is similarly suppressed by spreading in the direction in which the winding radius increases.

As a result, when the manipulator 1 is operated, the load of the rotational force applied to the one-wire power cable 12 can be reduced, so that the durability of the one-wire power cable 12 can be improved. Furthermore, twisting of the welding wire is reduced, and the welding wire can be stably fed, and the quality of the welding result can be improved.
Further, unlike the prior art 2, there is no need to limit the operating range and operating speed of the manipulator 1 in order to reduce the load applied to the one-wire power cable 12, so that the operating range and operating speed of the manipulator 1 are expanded. Therefore, adaptability to a workpiece having a complicated shape can be improved.
Further, since the twist of the one-wire power cable 12 when the manipulator 1 is operated can be suppressed, it is not necessary to consider the length of contraction due to the twist when the cable 12 is connected, and workability is improved. Can do. Moreover, since the slack which arises by considering the length which shrink | contracts by a twist can be eliminated, the fall of the feedability of the welding wire which arises by this slack can be prevented.

The above-described welding robot according to the present invention has been described using a manipulator having six axes. However, the present invention is not limited to the six axes, and is composed of a wrist first axis, a wrist second axis, and a wrist third axis. The present invention can also be applied to a manipulator having a shaft larger than the shaft.
Further, the present invention has been described with respect to a welding robot in which a welding torch is attached to the tip of a manipulator. However, the present invention is not limited to a welding robot, and can be applied to a handling robot, a painting robot, a thermal spray robot, and the like. .

It is a figure which shows the manipulator of the robot for welding of this invention. It is a figure for demonstrating the structure of the rotary electric power feeding member of the welding robot of this invention. It is a figure which shows the cross-section of the rotary electric power feeding member of the welding robot of this invention. It is a figure explaining the connection state to the rotary electric power feeding member 28 of the electric power feeding cable 29 of the welding robot of this invention. . It is a figure when the connection state to the rotary electric power feeding member 28 of the electric power feeding cable 29 of the welding robot of this invention is seen from the wire feeder side. It is a figure which shows the general structure of the robot for welding when using an articulated robot. It is a figure which shows the attachment structure of the welding torch 3 and the wire feeder 6 of the front-end | tip of the wrist part 2 of the manipulator 1 of the prior art 1. FIG. It is a figure which shows the manipulator of the robot for welding of the prior art 2. FIG. It is a figure for demonstrating the structure of the fixed electric power feeding member of the welding robot of the prior art 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Manipulator 2 Wrist part 3 Welding torch 4 Wire reel 5 Welding wire 6 Wire feeder 6a Welding wire delivery port 7 Welding power supply device 8 Teach pendant 9 Robot controller 10 Upper arm 11 Connecting member 12 One-wire power cable 13 Base 14 Turning Base 15 Lower Arm 16 Wire Feeder 16 Upper Arm 17 Body 18 Inserting Hole 19 Oscillating Body 20 Rotating Body 21 Oscillating Base 22 Reducer 23 Motor 24 Fixed Power Supply Member 25 Power Supply Cable 26 Gas Hose 27 Support Member 28 Rotating power supply member 29 Power supply cable 30 Gas hose 31 Bush 32 Guide adapter 33 Slip ring 34 Inlet guide 35 Coil liner 36 Power supply cable connection part 37 Gas hose connection part 38 Gas cylinder J1 1st axis J2 2nd axis J3 3rd axis J4 4th axis J5 5th axis J6 6th axis

Claims (1)

An upper arm with an insertion hole for a one-wire power cable;
A body that is attached to the distal end portion of the upper arm and has an insertion hole for the one-wire power cable formed at the proximal end portion thereof, and rotates around the wrist first axis in the longitudinal direction of the upper arm;
An oscillating body attached to the tip of the body and oscillating about a wrist second axis perpendicular to the wrist first axis;
A rotating body attached to the tip of the swinging body and rotating around a wrist third axis orthogonal to the wrist second axis;
A welding torch attached to the rotating body;
A wire feeder attached to the base end of the upper arm and delivering a welding wire substantially parallel to the wrist first axis;
A conductive power supply member provided between the upper arm and the wire feeder, wherein a power supply cable and a gas hose are connected to an outer peripheral surface, and an insertion hole of the welding wire is formed in a central axis;
The welding wire, which is connected to the distal end portion of the power supply member, passes through the insertion hole of the upper arm and the fuselage, extends in the longitudinal direction of the fuselage and travels in the center, and the power and gas are integrated. In the welding robot provided with the one-wire power cable to be supplied to the torch for operation,
A guide adapter fixed to the welding wire delivery port of the wire feeder and fed with the welding wire;
Before Symbol proximal end portion of the sheet collecting member is rotatably mounted on the distal end of the guide adapter,
Connecting the power supply cable and the gas hose by forming a slack wound around the outer periphery of the power supply member with a predetermined winding radius and number of turns depending on the material and shape of the power supply cable;
The welding robot , wherein the winding radius decreases or increases when the power supply member rotates together with the power supply cable and the gas hose .

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