Welding robot

Abstract

To solve a problem that it is difficult to teach a welding motion by a robot body accurately because of swinging of a torch tip caused when a teaching handle is attached to a position near a bending portion of a torch body.SOLUTION: A welding robot 1 includes a coupling portion 22 which couples a torch body 21 to a support arm 14 of a tip of a robot body 10. The coupling portion 22 includes a retaining mechanism 25 that retains a torch proximal end 21p via a connecting plug such 21c so that a torch distal end 21t is swingable with respect to the coupling portion 22. A teaching handle 40 is mounted to a welding torch 20 via a bracket 30. The bracket 30 comprises: a bracket body 31 detachably secured to the connecting plug 21c and provided in parallel to a first portion 20a of the torch body 21, which ranges from the torch proximal end 21p to a bending portion 21k, while forming a space therebetween; and a handle support portion 35 that supports the teaching handle 40 such that the handle distal end 40t of the teaching handle 40 is disposed at a position facing the bending portion 20k.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a welding robot.

Background Art

[0002] In recent years, human-cooperative robots configured to operate near an operator have been developed. For example, Patent Document 1 proposes a robot having a hand for gripping a component at the tip of a robot body. This robot has a teaching handle attached to the tip of the robot body for teaching the operation of the robot. The teaching handle is used to teach the operation of the robot body corresponding to the position where the hand moves by the operating force applied to the tip of the robot body while being gripped by the operator.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when such a robot with a teaching handle is used as a welding robot, since the teaching handle is attached to the tip of the robot, the position of the teaching handle is away from the torch body of the welding torch. Therefore, it is also conceivable to directly attach the teaching handle to the bent portion (bent part) of the torch body. However, when the torch tip contacts the outside, a holding mechanism is provided at the base end of the torch to hold the torch body so that the torch tip swings and the force acting on the torch body is released. For this reason, in the teaching operation, when an operating force is applied to the torch body via the teaching handle, a moment acts on the torch body so that the torch tip swings, making it difficult to accurately teach the welding operation to the robot body.

[0005] The present invention has been made in view of such points, and an object thereof is to provide a welding robot that can accurately teach a welding operation to a robot body while suppressing the swing of the torch tip even when a teaching handle is attached near the bent portion of the torch body.

Means for Solving the Problems

[0006] In view of the above problems, a welding robot according to the present invention is a welding robot including a multi-joint robot body and a welding torch attached to the tip of the robot body, the welding torch including a torch body and a connecting portion that connects the torch body to the tip of the robot body, the torch body having a bent portion where the torch body is bent between the torch base end and the torch tip of the torch body, the connecting portion having a holding mechanism that holds the torch base end via a connection plug so that the torch tip is swingable with respect to the connecting portion, the welding robot further including a teaching handle that teaches an operation of the robot body according to a position where the torch tip moves by an operation force applied to the tip of the robot body from an operator while being held by the operator, the teaching handle being attached to the welding torch via a bracket, the bracket being detachably fixed to the connection plug, and including a bracket body that is arranged in parallel with a first portion of the torch body from the torch base end to the bent portion with a space therebetween, and a handle support portion that supports the teaching handle at a position facing the bent portion so that a handle tip of the teaching handle is arranged.

[0007] According to the present invention, an operator can teach the operation of the robot body according to the position where the tip of the torch moves by applying an operating force from the teaching handle to the tip of the robot body while holding the teaching handle. In the present invention, the support portion of the bracket supports the teaching handle on the torch body such that the tip of the handle of the teaching handle is disposed at a position facing the bent portion. Thereby, during the teaching operation, the operator holds the teaching handle so that the tip of the handle is positioned in front of the operator, and by moving the tip of the held teaching handle, the tip of the torch of the torch body can be moved accurately and smoothly.

[0008] Furthermore, the bracket body is detachably fixed to the connection plug, and the bracket body is arranged in parallel with a first portion of the torch body from the torch base end to the bent portion with a space therebetween. Thereby, since the force of the operator acts on the connection plug from the teaching handle via the arm portion, even if the teaching handle is attached in the vicinity of the bent portion of the torch body, it is possible to accurately teach the welding operation to the robot body while suppressing the swing of the torch tip.

[0009] In a more preferred embodiment, a resin fixing plate is fixed to the connection plug, and the bracket body is fixed to the fixing plate so as to surround the connection plug in a non-contact state with the connection plug.

[0010] According to this embodiment, since the bracket body is fixed to the resin support plate in a non-contact state with the connection plug so as to surround the connection plug, electrical insulation between the connection plug and the bracket body can be ensured. Thereby, insulation between the welding torch and the teaching handle can be ensured.

[0011] More preferably, in a side view of the torch body and the teaching handle, the teaching handle extends in a direction away from a second portion from the bent portion to the torch tip, sandwiching a first virtual torch line along a first portion from the torch base end to the bent portion of the torch body. The bracket body is detachably fixed to the connection plug via the fixing plate by a detaching tool with a push button. The detaching tool releases the locking between the fixing plate and the bracket body when the push button is pushed. The detaching tool is attached to the bracket body and the fixing plate such that the pushing direction of the push button is a pushing direction from the bracket body side with respect to the fixing plate.

[0012] According to this aspect, during the teaching operation, the operator can accurately and smoothly move the torch tip of the torch body by gripping the teaching handle so that the handle tip is positioned in front of the operator and moving the handle tip of the gripped teaching handle. Further, the detaching tool is attached to the bracket body and the fixing plate such that the pushing direction of the push button is a pushing direction from the bracket body side with respect to the fixing plate. Thus, in front of the operator, when the operator grips the teaching handle with one hand and pushes the push button with a finger of the other hand from the bracket body side toward the fixing plate, the locking between the fixing plate and the bracket body is released. When the teaching handle is pulled toward the operator's front with the push button pushed, the teaching handle can be easily removed from the welding torch together with the bracket body.

[0013] More preferably, an opening is formed in the bracket body to expose a first portion of the torch body from the torch base end to the bent portion in a state where the torch body is viewed from the teaching handle side.

[0014] According to this aspect, since the torch body is formed with an opening that exposes the first portion from the base end of the torch to the bent portion, the first portion and the second portion of the torch body can be visually recognized during the teaching operation. Thereby, while visually recognizing the torch body, the welding operation can be accurately taught to the robot body.

[0015] More preferably, the bracket body is made of metal, the handle support portion is made of resin, and the handle support portion is composed of a pair of clamp members that sandwich the teaching handle.

[0016] According to this aspect, in a state where the teaching handle is sandwiched between a pair of clamp members, it can be fixed to the teaching handle on the bracket body. By making the pair of clamp members made of resin, electrical insulation between the connection plug and the teaching handle can be ensured.

Advantages of the Invention

[0017] According to the present invention, even if a teaching handle is attached near the bent portion of the torch body, the welding operation can be accurately taught to the robot body while suppressing the swing of the torch tip.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiment for Carrying out the Invention

[0019] Hereinafter, with reference to FIGS. 1 to 8, the welding robot 1 according to the present embodiment of the present invention will be described.

[0020] 1. Regarding the welding robot 1 As shown in FIGS. 1 and 2, the welding robot 1 includes an articulated robot body 10, a welding torch 20 attached to a support arm 14 at the tip of the robot body 10, and a teaching handle 40 attached to the welding torch 20 via a bracket 30. The welding torch 20 corresponds to the end effector of the robot body 10.

[0021] In the present embodiment, the welding robot 1 is a human-cooperative robot configured to operate near an operator. Specifically, the welding robot 1 has a direct teaching function in which an operator, who is a worker, teaches a welding operation. Specifically, the direct teaching function is a function of teaching a welding operation to the robot body 10 while changing the posture of the robot body 10 by directly applying an external force (operating force) from the operator to the tip of the robot body 10 through the teaching handle 40 while the operator holds the teaching handle 40. In addition to this, the welding robot 1 also has a function of performing manual welding by the operator using the teaching handle 40 before performing the main welding by the welding robot 1.

[0022] 2. Regarding the robot body 10 As shown in FIGS. 1 and 2, the robot main body 10 includes a base 11, and the base 11 is installed on the installation surface. The base 11 includes a fixed base 11a fixed to the installation surface and a swivel base 11b that swivels around a first axis J1 along a direction orthogonal to the installation surface.

[0023] An output shaft of a first motor (not shown) fixed to the fixed base 11a is connected to the swivel base 11b. Thereby, the swivel base 11b can be swiveled around the first axis J1 with respect to the fixed base 11a by driving the first motor. A first speed reducer (not shown) is attached to the output shaft of the first motor, and a first torque sensor (not shown) for detecting torque around the first axis J1 is attached to the output shaft of the first speed reducer. The first motor, the first speed reducer, and the torque sensor are housed inside the base 11.

[0024] The robot main body 10 has a lower arm 12 whose base end is pivotally attached to the swivel base 11b of the base 11, an upper arm 13 pivotally attached to the tip of the lower arm 12, and a support arm 14 pivotally attached to the tip of the upper arm 13. These arms are made of metal and are made of, for example, castings such as cast iron or aluminum alloy castings.

[0025] The base end of the lower arm 12 is pivotally supported by the swivel base 11b of the base 11 and is pivotally attached to the swivel base 11b so as to be rotatable around a second axis J2 via a second motor (not shown). Here, the second axis J2 is an axis parallel to the direction orthogonal to the first axis J1. By the power of the second motor, the lower arm 12 rotates around the second axis J2 with respect to the swivel base 11b. A second speed reducer (not shown) is attached to the output shaft of the second motor. A second torque sensor (not shown) for detecting torque around the second axis J2 is attached to the output shaft of the second speed reducer, and the second torque sensor is fixed to the lower arm 12. The lower arm 12 has a cylindrical shape, and various cables (not shown) are inserted inside.

[0026] The tip of the lower arm 12 is pivotally supported by the upper arm 13, and the upper arm 13 is pivotally attached to a third axis J3 parallel to the second axis J2 via a third motor (not shown). Inside the upper arm 13, the third motor is fixed to the upper arm 13. A third speed reducer is attached to the output shaft of the third motor. Further, a third torque sensor for detecting torque around the third axis J3 is attached to the output shaft of the third speed reducer, and the third torque sensor is fixed to the lower arm 12.

[0027] The upper arm 13 corresponds to the arm part of the robot body 10, and a third motor and a fourth motor (not shown) are accommodated therein. The output shaft of the fourth motor and the arm body of the upper arm 13 are connected via a power transmission belt or the like, and a fourth torque sensor for detecting torque around the fourth axis J4 is attached to the arm body. The fourth torque sensor is fixed to the arm body. By driving the fourth motor, it rotates around the fourth axis J4 along the longitudinal direction of the arm body.

[0028] The tip of the upper arm 13 corresponds to the part of the wrist of the robot body 10, and a support arm 14 for supporting a welding torch 20 (not shown) is attached. Specifically, the support arm 14 is pivotally attached to the tip of the upper arm 13 so as to be rotatable around a fifth axis J5 orthogonal to the fourth axis J4, and is rotatable around a sixth axis J6 along the longitudinal direction.

[0029] The upper arm 13 incorporates a fifth motor (not shown) for pivoting the support arm 14 with respect to the upper arm 13. The fifth motor is connected to the support arm 14 via a power transmission belt or the like built into the upper arm 13. The fifth motor and a sixth motor described later are built into the upper arm 13. Thus, the power of the fifth motor is transmitted to the power transmission belt built into the upper arm 13, and the support arm 14 rotates (oscillates) around the fifth axis J5 with respect to the upper arm 13.

[0030] Furthermore, the upper arm 13 incorporates a sixth motor (not shown), which is connected to the support arm 14 via a power transmission belt and bevel gears (not shown). Thus, by driving the sixth motor, the tip (main body part) of the support arm 14 can be rotated around the axis (specifically, the sixth axis J6).

[0031] As described above, in this embodiment, the robot body 10 includes first to sixth motors that perform driving around the axes of the respective axes from the first axis J1 to the sixth axis J6. The robot body 10 further includes first to fourth torque sensors that measure the torque acting on each axis only for the respective axes from the first axis J1 to the fourth axis J4. The first to fourth torque sensors are strain gauge type torque sensors.

[0032] Here, the welding robot 1 may measure the torque around the fifth axis J5 and the sixth axis J6 with a torque sensor. For example, the torque may be estimated by a control device (not shown) from the currents flowing through the fifth motor and the sixth motor.

[0033] The welding robot 1 includes a control device and a welding machine (not shown). The control device controls the operation of the welding robot 1 by controlling the driving of the first to sixth motors. The control device controls (1) the welding operation of the robot body 10, (2) the feeding speed of the feeding device that feeds the welding wire constituting the welding machine body (not shown) to the welding torch 20, (3) the welding applied voltage applied to the welding torch 20, (4) the supply timing of the shielding gas supplied to the welding torch 20, etc., to control the welding robot 1. More specifically, as the control of the welding robot 1, the control device performs control of the manual welding of the welding robot 1 for executing welding such as trial welding using the teaching handle 40 by the operator, control of the teaching of the welding robot 1 for performing teaching by an external operation (operation by an external force) by the teaching handle 40, control of the automatic welding of the welding robot 1 according to the taught operation, etc.

[0034] 3. Regarding the welding torch 20 The welding torch 20 includes a torch body 21 and a connecting portion 22 that connects the torch body 21 to the support arm 14 at the tip of the robot body 10. The torch body 21 has a bent portion 21k that bends the torch body 21 between the torch base end 21p of the torch body 21 and the torch tip 21t of the torch body 21.

[0035] Specifically, among the torch body 21, the first portion 21a from the torch base end 21p to the bent portion 21k is formed along a straight first torch virtual line T1. Among the torch body 21, the second portion 21b from the bent portion 21k to the torch tip 21t is formed along a straight second torch virtual line T2. Each of the first torch virtual line T1 and the second torch virtual line T2 passes through the axis of the first portion 21a and the second portion 21b of the torch body 21, and the angle formed by these is 135° in this embodiment and is in the range of 120° to 150°.

[0036] A path through which a welding wire passes, a gas flow path to which a shielding gas is supplied, etc. are formed in the torch body 21, and a nozzle is attached to the second portion 21b of the torch body 21. Since the structure of the torch body 21 is a general structure, a detailed description thereof is omitted. Further, the first portion 21a of the torch body 21 is connected to a connection plug 21c at the torch base end 21p of the torch body 21. Wiring (not shown) for applying a welding voltage to the torch body 21, piping (not shown) for supplying a welding shielding gas, etc. are connected to the connection plug 21c.

[0037] As shown in FIG. 5, the connecting portion 22 has a holding mechanism 25 that holds the torch base end 21p via the connection plug 21c so that the torch tip 21t can swing with respect to the connecting portion 22. Further, a holding rod 25a that constitutes the holding mechanism 25 described later is attached to the connection plug 21c, and the holding rod 25a extends along the first torch virtual line T1.

[0038] The end of the holding rod 25a has a dish-shaped head 25f, and the head 25f is accommodated in a casing 25h that constitutes the holding mechanism 25 so that the holding rod 25a can swing freely. A part of the shaft portion of the holding rod 25a and the connection plug 21c is covered with a flexible rubber cover 25c together with the lower end portion of the casing 25h. Thereby, the torch tip 21t can swing freely with respect to the casing 25h together with the holding rod 25a.

[0039] The casing 25h houses a mover 25d that abuts against the convex curved surface of the head 25f of the holding rod 25a. The mover 25d is disposed movably in the longitudinal direction of the casing 25h (the direction along the first torch virtual line T1) within the casing 25h. The casing 25h is provided with a biasing spring 25s that biases the mover 25d toward the head 25f of the holding rod 25a.

[0040] By configuring in this way, the torch main body 21 together with the holding rod 25a is held in the posture shown in FIG. 5. When an external force acts on the torch tip 21t of the torch main body 21, the holding rod 25a swings, the mover 25d that abuts against the convex curved surface of the head 25f is pushed up, and the biasing spring 25s is compressed. When the external force acting on the torch tip 21t is released, the restoring force of the biasing spring 25s pushes down the mover 25d, and the torch main body 21 together with the holding rod 25a can be returned to the posture shown in FIG. 5. When the mover 25d is pushed up to the uppermost limit, the limit switch 25p operates and the welding is interrupted.

[0041] In this way, damage to the torch main body 21 caused by an external force acting on the torch tip 21t can be prevented. In the present embodiment, the holding mechanism 25 uses the biasing spring 25s to hold the posture of the torch main body 21. For example, a magnet may be attached to a portion corresponding to the holding rod 25a, a magnet may be attached to a portion corresponding to the mover 25d, and the magnetic force of the magnets of both may hold the posture of the torch main body 21 swingably.

[0042] Note that the axes of the biasing spring 25s, the mover 25d, and the holding rod 25a from the upper part of the casing 25h have a through portion formed along the first torch virtual line T1. During welding, a welding wire is fed along this through portion. Further, in the present embodiment, the casing 25h of the holding mechanism 25 is fixed to the support arm 14 of the robot body 10 via L-shaped reinforcing angles and connectors 27 by fasteners 71, 72, etc. Specifically, the welding torch 20 is attached to the support arm 14 such that the sixth axis J6 of the support arm 14 is parallel to the first torch virtual line T1.

[0043] 4. Regarding the teaching handle 40 and its attachment state The teaching handle 40 is a member that teaches the operation of the robot body 10 according to the position where the torch tip 21t moves by the external force applied from the operator to the tip of the robot body 10 while the welding robot 1 is held by the operator.

[0044] As shown in FIG. 4, the teaching handle 40 is attached to the welding torch 20 such that the handle tip (tip surface) 40t is disposed at a position facing the bent portion 21k of the torch body 21. Specifically, the teaching handle 40 is detachably attached to the welding torch 20 via a bracket 30. When performing automatic welding by the welding robot 1, the teaching handle 40 is removed from the welding torch 20 together with the bracket 30 except for the fixing plate 36.

[0045] Here, as shown in FIG. 4, with the teaching handle 40 supported by the handle support portion 35, the torch body 21 and the teaching handle 40 are viewed from the side. In this side view, the teaching handle 40 extends in a direction away from the second portion 21b from the bent portion 21k to the torch tip 21t across the first torch virtual line T1 along the first portion 21a of the torch body 21 from the torch base end 21p to the bent portion 21k.

[0046] Specifically, among the torch body 21, the handle attachment angle θ formed by the second torch virtual line T2 along the second portion 21b from the bent portion 21k to the torch tip 21t and the first handle virtual line H1 along the direction in which the teaching handle 40 extends from the handle tip 40t is an obtuse angle. The handle attachment angle θ is preferably in the range of 110° to 140°. As is also apparent from FIG. 4, when the teaching handle 40 is viewed from the side, the teaching handle 40 curves downward from the handle tip 40t toward the handle base end 40p. Specifically, the teaching handle 40 curves along the arcuate second handle virtual line H2 from the handle tip 40t toward the handle base end 40p, and the straight first handle virtual line H1 corresponds to the tangent of the second handle virtual line H2 at the handle tip 40t. Note that the first handle virtual line H1 and the second handle virtual line H2 are lines passing through the center in the width direction of the teaching handle 40 when viewed from above, as shown in FIG. 7, and exist on the same virtual plane as the second torch virtual line T2.

[0047] In the present embodiment, the teaching handle 40 has a handle body 41 and a raised portion 45. The handle body 41 extends along the second handle virtual line H2 from a position facing the bent portion 21k of the torch body 21. The handle body 41 is a curved block-shaped (stick-shaped) portion in side view, and the upper surface 41f of the handle body 41 is a curved surface curved along the second handle virtual line H2. Since the teaching handle 40 curves downward, the operator can easily grip the teaching handle 40, and the operability of the teaching handle 40 can be improved. By placing the fingers up to the middle finger F3, ring finger F4, and little finger F5 of the operator on the raised portion 45, the gripability of the teaching handle 40 can be enhanced, so that the operability of the teaching handle 40 can be further improved.

[0048] As shown in FIG. 3, on the upper surface 41f of the handle body 41, a display panel 44, a function lever 43, a plurality of function buttons 42, etc. are arranged in order from the handle tip 40t side. A stop button 48 is attached to the end face of the handle tip 40t.

[0049] The function button 42 is a switch for switching to (a) a manual welding mode by an operator (worker), (b) a first teaching mode for teaching the welding operation of the robot body 10 by an external force applied by the operator (worker), (c) a second teaching mode for sending an operation signal to the robot body 10 by operating the function lever 43 or the like by the operator (worker), and teaching the robot body 10 to perform a welding operation. The state of the robot body 10 including such modes is displayed on the display panel 44. Further, the stop button 48 is a button for forcibly stopping the welding robot 1 in an emergency or the like. Signals output by the operator operating with such a function button 42 and function lever 43 are transmitted to the above-described control device via a cable 49 connected to the handle base end 40p of the teaching handle 40.

[0050] Furthermore, the teaching handle 40 includes a raised portion 45 that protrudes from the lower part of the handle body 41. The raised portion 45 is a portion for hooking the operator's finger when the operator holds the teaching handle 40. The height of the raised portion 45 from the handle body 41 decreases as it progresses from the handle tip 40t side to the handle base end 40p side.

[0051] Among the surfaces 45a of the raised portion 45, an operation switch 46 is arranged on the end face 45b on the handle tip 40t side. The operation switch 46 is a switch that permits the movement of the robot body 10 by an external force with respect to the robot body 10 whose movement is restricted. Since the operation switch 46 is arranged on the end face on the handle tip 40t side of the surface of the raised portion 45, the operator can easily press the operation switch 46 with the index finger F2 of the operator with the fingers from the middle finger F3 to the little finger F5 of the operator hooked on the raised portion 45.

[0052] Here, specifically, the first to sixth motors described above are attached to the robot body 10. In a state where the operation switch 46 is not pressed (OFF state), the first to sixth motors are mechanically or electrically locked. When the operation switch 46 is pressed (ON state), the mechanical or electrical lock of the first to sixth motors is released. Here, the release of the lock may be set to continue by continuously pressing the operation switch 46, or it may be set to switch between lock and release of the lock by pressing the operation switch 46 once. In this way, the restriction (lock) on the movement of the robot body 10 is released, and the movement of the robot body 10 is permitted.

[0053] 5. Regarding the bracket 30 As shown in FIGS. 3 and 6, the bracket 30 has a bracket body 31 that is detachably fixed to the connection plug 21c of the welding torch 20, and a handle support portion 35 that is continuous with the bracket body 31 and supports the teaching handle 40 on the welding torch 20. The bracket body 31 is arranged in parallel at intervals on the first portion of the torch body 21 from the torch base end 21p to the bent portion 21k.

[0054] In this embodiment, a fixing plate 36 made of an insulating resin such as a polyolefin resin, which is a material having electrical insulation, is fixed to the connection plug 21c. As shown in FIG. 6, a pair of through holes 36h are formed in the fixing plate 36, and the fixing plate 36 is attached to the connection plug 21c of the welding torch 20 by a pair of fasteners 78. A convex portion 36t that engages with the recess of the connection plug 21c is formed at the center of the fixing plate 36, and a pair of locking pins 39p that are locked by the detaching tool 39 are erected on both sides in the horizontal direction of the fixing plate 36.

[0055] The bracket body 31 is a metallic part made of a metallic material such as aluminum or stainless steel, for example. The bracket body 31 is fixed to the fixing plate 36 so as to surround the connection plug 21c in a state of being non-contact with the connection plug 21c. On the bracket body 31, from the teaching handle 40 side, along the first torch virtual line T1, a cover part 31c surrounding the connection plug 21c and a pair of flange parts 31t, 31t formed on both sides of the cover part 31c are formed. Each flange part 31t is provided with a through hole 31g into which the detaching tool 39 is inserted.

[0056] As a result, as shown in FIG. 7, a gap S can be formed between the bracket body 31 (the cover part 31c thereof) and the connection plug 21c. In the present embodiment, since the bracket body 31 is fixed to the resin-made fixing plate 36 in a state of being non-contact with the connection plug 21c so as to surround the connection plug 21c, electrical insulation between the connection plug 21c and the bracket body 31 can be ensured. Thereby, it is possible to avoid an operator from directly touching the welding torch 20 and to ensure electrical insulation between the welding torch 20 and the teaching handle 40.

[0057] The bracket body 31 is detachably fixed to the connection plug 21c by the detaching tool 39 with a push button 39b via the fixing plate 36 fixed to the connection plug 21c. The detaching tool 39 is configured such that when the push button 39b is pushed, the locking between the fixing plate 36 and the bracket body 31 is released. The detaching tool 39 is attached to the bracket body 31 and the fixing plate 36 such that the pushing direction of the push button 39b is the pushing direction from the bracket body 31 side with respect to the fixing plate 36.

[0058] For example, as such a detachable tool 39, a detachable tool called a so-called one-way clamper can be cited. Specifically, as shown in FIG. 7, the detachable tool 39 includes a cylindrical housing 39a, and a movable body 39t that moves along the axial direction of the housing 39a and a biasing spring 39s that biases the push button 39b are accommodated in the housing 39a. The movable body 39t has a shape with a constricted center in the axial direction. The push button 39b slidably covers the movable body 39t, and a plurality of retracting balls 39k for retracting the movable body 39t are arranged around the axis on the end face of the push button 39b. Further, a plurality of locking balls 39j that lock to the locking pin 39p are arranged around the axis on the tip side of the movable body 39t in the housing 39a.

[0059] When attaching the bracket body 31 to the fixing plate 36, the flange portion 31t of each bracket body 31 is brought into contact with the fixing plate 36, and the locking pin 39p erected on the fixing plate 36 is inserted into the housing 39a of the detachable tool 39 and locked to the locking ball 39j of the locking pin 39p. Thereby, the bracket body 31 is attached to the connection plug 21c by the detachable tool 39 via the fixing plate 36 fixed to the connection plug 21c.

[0060] On the other hand, when removing the bracket body 31 from the fixing plate 36, by pushing in the push button 39b, the retracting ball 39k enters the constriction of the movable body 39t. In this state, when the pushing of the push button 39b is released, by the restoring force of the biasing spring 39s, the push button 39b returns to its original position, and the retracting ball 39k and the movable body 39t are drawn into the push button 39b. At this time, the locking between the locking pin 39p and the locking ball 39j is released. Thereby, the bracket body 31 can be removed from the fixing plate 36 fixed to the connection plug 21c.

[0061] Thus, according to this embodiment, the detaching / attaching tool 39 is attached to the bracket main body 31 and the fixed plate 36 such that the pushing direction of the push button 39b of the detaching / attaching tool 39 is the pushing direction from the bracket main body 31 side with respect to the fixed plate 36. Thereby, from the state shown in FIG. 3, in front of the operator, while gripping the teaching handle 40 with one hand H of the operator, when the push button 39b is pushed from the bracket main body 31 side toward the fixed plate 36 with the fingers of the other hand of the operator, the locking by the detaching / attaching tool 39 is released. When the teaching handle 40 is pulled toward the front of the operator with the push button 39b pushed in, the teaching handle 40 can be easily removed from the welding torch 20 together with the bracket main body 31.

[0062] Furthermore, in this embodiment, a pair of arms 31a are formed on the bracket main body 31. Specifically, the arms 31a extend from both sides of the cover portion 31c so as to be juxtaposed with the first portion 21a of the torch main body 21 from the torch base end 21p to the bent portion 21k. Thereby, an opening 31w is formed in the bracket main body 31 to expose the first portion 21a of the torch main body 21 from the torch base end 21p to the bent portion 21k in a state where the torch main body 21 is viewed from the teaching handle 40 side. Thereby, during the manual welding operation and the teaching operation, the first portion 21a and the second portion 21b of the torch main body 21 can be visually recognized. As a result, while visually recognizing the torch main body 21, manual welding can be performed with high accuracy, and the welding operation can be accurately taught to the robot main body 10. Furthermore, it is also possible to press the stop button 48 by passing the finger of the operator through the opening 31w.

[0063] The handle support portion 35 is a resin portion made of an insulating resin such as a polyolefin resin that supports the teaching handle 40 so that the handle tip 40t of the teaching handle 40 is disposed at a position facing the bent portion 21k. In the present embodiment, the handle support portion 35 includes an upper clamp member 33 and a lower clamp member 34 (a pair of clamp members 33 and 34) that sandwich a portion on the tip side of the teaching handle 40.

[0064] In the present embodiment, at the tip (lower end) of each arm 31a of the bracket body 31, a contact portion 31b that contacts the upper and lower clamp members 33 and 34 is formed. On the contact portion 31b, a contact surface 31f that contacts the end surfaces 33f and 34f of the upper and lower clamp members 33 and 34 is formed so as to face the teaching handle 40 side. In the contact portion 31b, an insertion hole 31h through which a fastener 74 such as a bolt fastened to the upper and lower clamp members 33 and 34 is inserted is formed. Each of the upper clamp member 33 and the lower clamp member 34 is attached to the contact portion 31b of the bracket body 31 by being fastened to a fastener 72 inserted through the insertion hole 31h from the torch body 21 side.

[0065] As shown in FIG. 4, in a side view, the contact surface 31f of the contact portion 31b and the end surfaces 33f and 34f of the pair of upper and lower clamp members 33 and 34 that contact the contact surface 31f are inclined with respect to the first torch virtual line T1. Thereby, it is possible to suppress a shearing force from acting on the screw portion of the fastener 72 in a direction orthogonal to the axial direction of the fastener 72 due to an external force in the vertical direction of the operator acting from the teaching handle 40.

[0066] Upper clamp member 33 and lower clamp member 34 are formed with recesses 33r and 34r corresponding to the teaching handle 40. When attaching the teaching handle 40, the upper clamp member 33 and the lower clamp member 34 are clamped from above and below, a fastener (not shown) is inserted through the four through holes 33h of the teaching handle 40, and the fastener is tightened into the lower clamp member 34. Thereby, the teaching handle 40 can be held on the welding torch 20 via the bracket 30. By making the upper and lower clamp members 33 and 34 of resin, electrical insulation between the connection plug 21c and the teaching handle 40 can be ensured. Further, an opening window 33w corresponding to the shape of the display panel 44 is formed in the upper clamp member 33. The operator can perform the operation while viewing the display panel 44 through the opening window 33w of the teaching handle 40.

[0067] 6. Manual Welding and Teaching Hereinafter, the teaching of the welding robot in manual welding and automatic welding using the welding robot 1 will be described together with its effects. For example, in the case of manual welding, (a) the operator (worker) sets the manual welding mode by the function button 42. When the operator briefly presses the operation switch 46, the mechanical or electrical lock of the first to sixth motors is released. Thereby, the operator can grip the teaching handle 40 and move the torch tip 21t of the torch body 21 along the welding line while changing the posture of the robot body 10 by the external force (operating force) from the teaching handle 40 according to the welding operation. Specifically, according to the signals detected from the above-described torque sensors of the respective axes attached to the robot body 10 or a force sensor (not shown) that measures each force in the three-dimensional directions applied to the tip of the robot body 10 by the external force from the teaching handle 40, the above-described control device controls the driving of the first to sixth motors of the robot body 10.

[0068] In this way, while operating the robot main body 10 by an external force, when performing the welding operation of the robot main body 10, by pressing the operation switch 46 again with the index finger F2, an arc discharge is generated from the tip of a welding wire (not shown) located at the torch tip 21t to melt the wire, and the wire is fed. Thereby, an operator (worker) can perform manual welding using the welding robot 1. In this embodiment, the operation switch 46 is used to unlock the robot main body 10 and execute the welding operation (welding by arc discharge), but it is not limited to such a usage method, and the usage method of at least one of the function button 42 and the function lever 43 may be set. For example, by continuously pressing the operation switch 46 with the index finger F2, the restriction (lock) on the movement of the robot main body 10 is released, and when executing the welding operation, at least one of the function button 42 and the function lever 43 may be operated with, for example, the thumb F1.

[0069] For example, during teaching, when the function button 42 is used and (b) the operator (worker) sets the first teaching mode, if the operation switch 46 is continuously pressed, the mechanical or electrical lock release of the first to sixth motors continues. Thereby, while gripping the teaching handle 40, the operator continuously presses the operation switch 46 in accordance with the welding operation, and changes the posture of the robot main body 10 by the external force (operating force) from the teaching handle 40, and moves the torch tip 21t of the welding torch 20 along the welding line. Specifically, as described above, according to the signal detected from the above-described torque sensor or force sensor or the like by the external force from the teaching handle 40, the above-described control device controls the driving of the first to sixth motors of the robot main body 10. At this time, the rotation position up to the first to sixth motors is calculated based on the detection signals of the encoders (not shown) of the first to sixth motors. Thereby, the welding operation of the robot main body 10 by the operator can be taught.

[0070] For example, when teaching, if the operator (worker) sets the second teaching mode using the function button 42, the operator may perform teaching similar to that with a generally known teaching pendant by operating the function lever 43 or the like. Therefore, detailed description thereof is omitted.

[0071] Note that in the state where the above-described operation switch 46 is pressed (ON state), the first to sixth motors are mechanically or electrically locked. For example, motors that do not need to be driven, such as the first motor, may maintain the locked state according to the posture of the articulated robot in teaching.

[0072] According to this embodiment, the operator can, while gripping the teaching handle 40, apply an external force from the teaching handle 40 to the tip of the robot body 10 to teach the operation of the robot body 10 according to the position where the torch tip 21t moves. Further, the teaching handle 40 is attached to the welding torch 20 such that the handle tip 40t is disposed at a position facing the bent portion 21k, and the torch body 21 extends in a direction away from the second portion 21b from the bent portion 21k to the torch tip 21t with the first torch virtual line T1 interposed therebetween. Thereby, during the teaching operation, the operator grips the teaching handle 40 such that the handle tip 40t is positioned in front of the operator, and by moving the handle tip 40t of the gripped teaching handle 40, the torch tip 21t of the torch body 21 can be moved accurately and smoothly.

[0073] In particular, as shown in Fig. 8(a), since the handle mounting angle θ formed by the second torch virtual line T2 and the first handle virtual line H1 is an obtuse angle, it is close to the arrangement state of the handle-type torch body 21A and the handle 41A for manual welding shown in Fig. 8(b). That is, the angle θA formed by the torch virtual line T3 of the torch body 21A and the handle virtual line H3 of the handle 40A (handle body 41) is close to the handle mounting angle θ shown in Fig. 8(a). Also, since the position of the operation switch 46 of the teaching handle 40 is also close to the position of the operation switch 46A of the handle 41A, the operator can press the operation switch 46 with the index finger.

[0074] Therefore, during manual welding, since the welding robot 1 can perform welding close to the operation of the operator performing the welding, a highly accurate weld W can be formed by manual welding on the workpieces P1 and P2 to be welded. Furthermore, during teaching, since the welding robot 1 can be taught an operation close to the operation of the operator performing the welding, a highly accurate weld W can be formed by automatic welding on the workpieces P1 and P2 to be welded. In particular, if the handle mounting angle is in the range of 110° to 140°, since it is close to the arrangement state of the handle-type torch body 21A and the handle 40A, such an effect can be expected even more.

[0075] Furthermore, in this embodiment, by using the above-described bracket 30, during manual welding work and teaching work, the operator (worker) holds the teaching handle 40 so that the handle tip 40t is located in front of the operator. Furthermore, the operator can accurately and smoothly move the torch tip 21t of the torch body 21 by moving the handle tip 40t of the held teaching handle 40. In particular, by arranging the torch body 21 and the teaching handle 40 so that the first handle virtual line H1 and the second torch virtual line T2 are on the same virtual plane, such an effect can be exerted even more.

[0076] Furthermore, the bracket main body 31 is detachably fixed to the connection plug, and the bracket main body 31 is arranged in parallel at a distance from the first portion 21a of the torch main body 21 from the torch base end 21p to the bent portion 21k. As a result, the force of the operator acts from the teaching handle 40 to the connection plug 21c via the bracket main body 31. For this reason, even if the teaching handle 40 is attached in the vicinity of the bent portion 21k of the torch main body 21, manual welding can be performed while suppressing the swing of the torch tip 21t, and the welding operation can be accurately taught to the robot main body 10.

[0077] As described above, the embodiments of the present invention have been described in detail. However, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the spirit of the present invention described in the claims.

Explanation of reference numerals

[0078] 1: Welding robot, 10: Robot main body, 14: Support arm, 20: Welding torch, 21: Torch main body, 21a: First portion, 21b: Second portion, 21c: Connection plug, 21k: Bent portion, 21p: Torch base end, 21t: Torch tip, 22: Connecting portion, 25: Holding mechanism, 30: Bracket, 30w: Opening, 31: Bracket main body, 33: Upper clamp member, 34: Lower clamp member, 35: Handle support portion, 36: Fixed plate, 39: Detaching tool, 39b: Button, 40: Teaching handle, 40t: Handle tip, K1: First torch virtual line

Claims

1. A welding robot comprising a multi-joint robot body and a welding torch attached to the tip of the robot body, wherein the welding torch includes a torch body and a connecting portion that connects the torch body to the tip of the robot body, the torch body has a bent portion that bends the torch body between the torch base end and the torch tip of the torch body, the connecting portion has a holding mechanism that holds the torch base end via a connection plug so that the torch tip is swingable with respect to the connecting portion, the welding robot further includes a teaching handle that teaches the operation of the robot body according to the position where the torch tip moves by an operating force applied to the tip of the robot body by an operator while being held by the operator, the teaching handle is attached to the welding torch via a bracket, the bracket has a bracket body that is detachably fixed to the connection plug and is arranged in parallel with a space from the torch base end to the first portion up to the bent portion of the torch body, and a handle support portion that supports the teaching handle so that the handle tip of the teaching handle is arranged at a position facing the bent portion, and is characterized by the above.

2. A resin-made fixing plate is fixed to the connection plug, The welding robot according to claim 1, wherein the bracket body is fixed to the fixing plate so as to surround the connection plug in a state of being non-contact with the connection plug.

3. When the torch body and the teaching handle are viewed from the side, the teaching handle extends in a direction away from the second portion from the bent portion to the torch tip across a first virtual torch line along the first portion from the torch base end to the bent portion of the torch body, the bracket body is detachably fixed to the connection plug via the fixing plate by a detachable tool with a push button, the detachable tool releases the locking between the fixing plate and the bracket body when the push button is pushed. The detachable tool is attached to the bracket body and the fixed plate such that the pressing direction of the pressing button is the pressing direction from the bracket body side with respect to the fixed plate, the welding robot according to claim 2.

4. The welding robot according to claim 1, wherein an opening is formed in the bracket body to expose a first portion of the torch body from the torch base end to the bent portion in a state where the torch body is viewed from the teaching handle side.

5. The bracket body is made of metal, and the handle support portion is made of resin. The welding robot according to claim 1, wherein the handle support portion is composed of a pair of clamp members that sandwich the teaching handle.

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