welding robot

Abstract

To solve a problem that it is difficult to teach a multi-joint robot a behavior similar to a behavior of a worker performing welding.SOLUTION: A teaching handle 40 is mounted to a welding torch 20 such that a handle distal end 40t is disposed at a position facing a bending portion 21k. The teaching handle 40 extends in a direction away from a second portion 21b of a torch body 21, which ranges from the bending portion 21k to a torch distal end 21t, with a first torch virtual line T1 along a first portion 21a, which ranges from a torch proximal end 21p to the bending portion 21k, interposed therebetween. A handle mounting angle θ is an obtuse angle, which is formed between a second torch virtual line T2 along the second portion 21b of the torch body 21, which ranges from the bending portion 21k to the torch distal end 21t, and a first handle virtual line H1 along the direction in which the teaching handle 40 extends from the handle distal end 40t. The handle mounting angle θ ranges from 110° to 140° . The teaching handle 40 is detachably attached to the welding torch 20.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a welding robot and a teaching handle. [Background technology]

[0002] In recent years, human-collaborative robots that are configured to operate in the vicinity of workers have been developed. For example, Patent Document 1 proposes a robot equipped with a hand for grasping a part at the tip of the robot body. This robot has a teaching handle attached to the tip of the robot body, which is used to teach the robot how to operate. The teaching handle is held by an operator and is used to teach the robot body how to operate in accordance with the position of the moving hand by applying an external force (operating force) from the operator to the tip of the robot body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-199174 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a robot equipped with such a teaching handle is used as a welding robot, the teaching handle is attached to the tip of the robot, so the position of the teaching handle is separated from the torch body of the welding torch. As a result, even if a teaching handle is used, it is difficult to teach the robot body movements similar to those of a welding worker and have the welding robot perform welding with precision.

[0005] The present invention has been made in consideration of these points, and its object is to provide a welding robot and a teaching handle that can teach an articulated robot to perform movements similar to those of a worker performing welding. [Means for solving the problem]

[0006] In view of the above problems, a welding robot according to the present invention is a welding robot including an articulated robot body and a welding torch attached to a 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, and the torch body has a bending portion that bends the torch body between the torch base end of the torch body and the torch tip of the torch body, and the welding robot further includes a teaching handle that, when held by an operator, teaches the robot body to operate in accordance with a position to which the torch tip moves by an external force applied from the operator to the tip of the robot body, and The teaching handle is attached to the welding torch so that the handle tip is positioned opposite the bent portion, and when the torch body and the teaching handle are viewed from the side, the teaching handle extends in a direction away from a second portion of the torch body from the bent portion to the torch tip, across a first torch imaginary line along a first portion of the torch body from the torch base end to the bent portion, and the handle mounting angle formed by the second torch imaginary line along the second portion of the torch body from the bent portion to the torch tip and the first handle imaginary line along the direction in which the teaching handle extends from the handle tip is an obtuse angle.

[0007] According to the present invention, an operator can apply an external force from the teaching handle to the tip of the robot body while holding the teaching handle, thereby teaching the robot body to operate in accordance with the position of the torch tip. In this invention, the teaching handle is attached to the welding torch so that the handle tip is located opposite the bent portion, and the torch body extends across the first torch imaginary line in a direction away from the second portion from the bent portion to the torch tip. As a result, during teaching work, the operator holds the teaching handle so that the handle tip is located in front of the operator, and by moving the handle tip of the teaching handle they are holding, the torch tip of the torch body can be moved accurately and smoothly.

[0008] The handle mounting angle formed by the second torch imaginary line and the first handle imaginary line is an obtuse angle, which is similar to the arrangement of a handle-type welding torch and handle, and therefore it is possible to teach the robot body instructions that are similar to the movements of a worker performing welding. In particular, if the handle mounting angle is in the range of 110° to 140°, this effect can be further enhanced.

[0009] In a more preferred embodiment, the teaching handle is curved downward when viewed from the side.

[0010] According to this aspect, the teaching handle is curved downward, so that the operator can easily grip the teaching handle, thereby improving the operability of the teaching handle.

[0011] In a more preferred embodiment, the teaching handle has a handle body extending from an opposing position opposite the bent portion, and a raised portion for a finger hook that rises from the bottom of the handle body and on which the operator's fingers can be hooked when the operator is holding the teaching handle, and the height of the raised portion from the handle body decreases as it progresses from the handle tip side to the handle base end side.

[0012] According to this aspect, the operator can hook his / her fingers from the middle finger to the little finger on the raised portion, thereby improving the grip of the teaching handle, thereby further improving the operability of the teaching handle.

[0013] In a more preferred embodiment, the teaching handle is provided with an operation switch that allows the robot body, whose movement is restricted, to move due to the external force, and the operation switch is located on the end face of the raised portion on the tip side of the handle.

[0014] According to this aspect, the operation switch is located on the end face of the raised portion on the tip side of the handle, so that the operator can press the operation switch with his / her index finger while placing his / her fingers from the middle finger to the little finger on the raised portion.

[0015] In a more preferred embodiment, the teaching handle is used in the above-described welding robot, and the teaching handle is detachably attached to the welding torch.

[0016] According to this aspect, the teaching handle is removably attached to the welding torch, so that the teaching handle can be removed and the robot body can be operated in accordance with the operator's actions during teaching, allowing for highly accurate welding. [Effects of the Invention]

[0017] According to the present invention, it is possible to teach an articulated robot movements that are similar to those of a worker performing welding. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a schematic perspective view of a welding robot according to an embodiment of the present invention, viewed from the front. FIG. [Figure 2] FIG. 2 is a perspective view of the welding robot shown in FIG. 1 as seen from behind. [Figure 3]FIG. 2 is a schematic perspective view illustrating an attachment state of a teaching handle of the welding robot shown in FIG. 1. [Figure 4] FIG. 4 is a side view of the welding robot shown in FIG. 3. [Figure 5] FIG. 5 is a partial cross-sectional view of the welding robot shown in FIG. [Figure 6] FIG. 3 is an exploded perspective view of the welding robot shown in FIG. 2. [Figure 7] FIG. 6 is a cross-sectional view taken along the line AA shown in FIG. 5. [Figure 8] 5(a) is a side view for explaining a teaching operation using the welding robot shown in FIG. 4, and FIG. 5(b) is a side view for explaining a welding operation using a handle-type welding torch. DETAILED DESCRIPTION OF THE INVENTION

[0019] A welding robot 1 according to this embodiment of the present invention will be described below with reference to FIGS.

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

[0021] In this embodiment, the welding robot 1 is a human-collaborative robot configured to operate in the vicinity of a worker. Specifically, the welding robot 1 has a direct teaching function that allows the operator, who is the worker, to teach the welding operation. Specifically, the direct teaching function is a function in which, while holding the teaching handle 40, the operator applies an external force (operating force) directly to the tip of the robot body 10 via the teaching handle 40, thereby teaching the robot body 10 a welding operation while changing the posture of the robot body 10. In addition, the welding robot 1 also has a function that allows the operator to perform manual welding using the teaching handle 40 before performing main welding using the welding robot 1.

[0022] 2. About the robot body 10 1 and 2, the robot body 10 includes a base 11, which is installed on an installation surface. The base 11 includes a fixed base 11a fixed to the installation surface, and a swivel base 11b that rotates around a first axis J1 that extends in a direction perpendicular to the installation surface.

[0023] The output shaft of a first motor (not shown) fixed to the fixed base 11a is connected to the swivel base 11b. This allows the swivel base 11b to rotate around a first axis J1 relative to the fixed base 11a by driving the first motor. A first reducer (not shown) is attached to the output shaft of the first motor, and a first torque sensor (not shown) that detects torque around the first axis J1 is attached to the output shaft of the first reducer. The first motor, first reducer, and torque sensor are housed inside the base 11.

[0024] The robot body 10 has a lower arm 12 whose base end is pivotally attached to the swivel base 11b, 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, such as cast iron or aluminum alloy casting.

[0025] The base end of the lower arm 12 is journaled on a swivel base 11b of the base 11, and is pivotally attached to the swivel base 11b about a second axis J2 via a second motor (not shown). The second axis J2 is an axis parallel to a direction perpendicular to the first axis J1. The power of the second motor causes the lower arm 12 to rotate about the second axis J2 relative to the swivel base 11b. A second reducer (not shown) is attached to the output shaft of the second motor. A second torque sensor (not shown) that detects torque about the second axis J2 is attached to the output shaft of the second reducer, and the second torque sensor is fixed to the lower arm 12. The lower arm 12 is cylindrical, and various cables (not shown) are inserted therein.

[0026] The tip of the lower arm 12 is journaled to an upper arm 13, which is pivotally mounted via a third motor (not shown) to a third axis J3 parallel to the second axis J2 so as to be freely rotatable. Inside the upper arm 13, a third motor is fixed to the upper arm 13. A third reducer is attached to the output shaft of the third motor. Furthermore, a third torque sensor that detects torque around the third axis J3 is attached to the output shaft of the third reducer, and the third torque sensor is fixed to the lower arm 12.

[0027] The upper arm 13 corresponds to the arm of the robot body 10 and houses a third motor and a fourth motor (not shown). 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 that detects torque around the fourth axis J4 is attached to the arm body. The fourth torque sensor is fixed to the arm body. Driven by the fourth motor, the arm body 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 wrist of the robot body 10, and has attached thereto a support arm 14 that supports a welding torch 20 (not shown). Specifically, the support arm 14 is pivotally attached to the tip of the upper arm 13 so as to be rotatable about a fifth axis J5 that is perpendicular to the fourth axis J4, and is rotatable about a sixth axis J6 that extends in the longitudinal direction.

[0029] A fifth motor (not shown) that pivots the support arm 14 relative to the upper arm 13 is built into 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. As a result, the power of the fifth motor is transmitted to the power transmission belt built into the upper arm 13, causing the support arm 14 to rotate (swing) about the fifth axis J5 relative to the upper arm 13.

[0030] Furthermore, a sixth motor (not shown) is built into the upper arm 13, and the sixth motor is connected to the support arm 14 via a power transmission belt and a bevel gear (not shown). This allows the tip (main body) of the support arm 14 to rotate around the axis (specifically, the sixth axis J6) by driving the sixth motor.

[0031] As described above, in this embodiment, the robot body 10 is provided with first to sixth motors for driving each of the first to sixth axes J1 to J6 around the axis. The robot body 10 is further provided with first to fourth torque sensors for measuring torque acting on each axis only, 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 using a torque sensor, but the torque may also be estimated by a control device (not shown), for example, from the current flowing through the fifth motor and the sixth motor.

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

[0034] 3. About 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 at which the torch body 21 is bent between the torch base end 21p of the torch body 21 and the torch tip end 21t of the torch body 21.

[0035] Specifically, the first portion 21a of the torch body 21, from the torch base end 21p to the bent portion 21k, is formed along a linear first torch imaginary line T1. The second portion 21b of the torch body 21, from the bent portion 21k to the torch tip 21t, is formed along a linear second torch imaginary line T2. The first torch imaginary line T1 and the second torch imaginary line T2 pass through the axes of the first portion 21a and the second portion 21b of the torch body 21, respectively, and the angle they form is 135° in this embodiment, and is in the range of 120° to 150°.

[0036] Torch body 21 is formed with a path through which a welding wire passes, a gas flow path through which shielding gas is supplied, and the like, and a nozzle is attached to second portion 21b of torch body 21. The structure of torch body 21 is a common structure, so a detailed description will be omitted. Furthermore, first portion 21a of torch body 21 is connected to connection plug 21c at torch base end 21p of torch body 21. Wiring (not shown) that applies a welding voltage to torch body 21, piping (not shown) that supplies welding shielding gas, and the like are connected to connection plug 21c.

[0037] 5, coupling portion 22 has a holding mechanism 25 that holds torch base end 21p via connection plug 21c so that torch tip 21t can swing freely relative to coupling portion 22. Furthermore, connection plug 21c is fitted with holding rod 25a that constitutes holding mechanism 25, which will be described later, and holding rod 25a extends along first torch imaginary line T1.

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

[0039] Casing 25h accommodates mover 25d, which abuts against the convex curved surface of head 25f of holding rod 25a. Mover 25d is disposed within casing 25h so as to be movable in the longitudinal direction of casing 25h (the direction along first torch imaginary line T1). Casing 25h is provided with biasing spring 25s that biases mover 25d toward head 25f of holding rod 25a.

[0040] With this configuration, the torch body 21, together with the holding rod 25a, is held in the position shown in Figure 5. When an external force acts on the torch tip 21t of the torch body 21, the holding rod 25a swings, pushing up the mover 25d that abuts the convex curved surface of the head 25f and compressing the biasing spring 25s. When the external force on the torch tip 21t is released, the restoring force of the biasing spring 25s pushes down the mover 25d, returning the torch body 21 together with the holding rod 25a to the position shown in Figure 5. When the mover 25d is pushed up to its upper limit, the limit switch 25p is activated and welding is interrupted.

[0041] In this way, it is possible to prevent damage to torch body 21 due to an external force acting on torch tip 21t. In this embodiment, holding mechanism 25 uses biasing spring 25s to hold the position of torch body 21, but for example, a magnet may be attached to the part corresponding to holding rod 25a, and another magnet may be attached to the part corresponding to mover 25d, and the magnetic force of both magnets may be used to hold the position of torch body 21 in a swingable manner.

[0042] A through-hole is formed through the upper portion of casing 25h, along the first torch imaginary line T1, with the axes of biasing spring 25s, movable element 25d, and holding rod 25a. During welding, the welding wire is fed along this through-hole. Furthermore, in this embodiment, casing 25h of holding mechanism 25 is fixed to support arm 14 of robot main body 10 by fasteners 71, 72, etc., via an L-shaped reinforcing angle and connector 27. Specifically, welding torch 20 is attached to support arm 14 so that sixth axis J6 of support arm 14 and first torch imaginary line T1 are parallel to each other.

[0043] 4. Teaching handle 40 and its installation status The teaching handle 40 is a component that, when held by an operator, teaches the welding robot 1 the operation of the robot body 10 according to the position to which the torch tip 21t moves by applying an external force from the operator to the tip of the robot body 10.

[0044] 4, teaching handle 40 is attached to welding torch 20 so that handle tip (tip surface) 40t is located in a position opposite bent portion 21k of torch body 21. Specifically, teaching handle 40 is detachably attached to welding torch 20 via bracket 30. When performing automatic welding using welding robot 1, teaching handle 40, together with bracket 30, is removed from welding torch 20 except for fixing plate 36.

[0045] 4, the torch body 21 and teaching handle 40 are viewed from the side with the teaching handle 40 supported by the handle support 35. In this side view, the teaching handle 40 extends in a direction away from the second portion 21b of the torch body 21, from the torch base end 21p to the bent portion 21k, across a first torch imaginary 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, the handle mounting angle θ formed by the second torch imaginary line T2 along the second portion 21b of the torch body 21, from the bent portion 21k to the torch tip 21t, and the first handle imaginary line H1 along the direction in which the teaching handle 40 extends from the handle tip 40t, is an obtuse angle. The handle mounting angle θ is preferably in the range of 110° to 140°. As is clear from FIG. 4, when viewed from the side, the teaching handle 40 curves downward from the handle tip 40t to the handle base end 40p. Specifically, the teaching handle 40 curves from the handle tip 40t to the handle base end 40p along the arc-shaped second handle imaginary line H2, and the linear first handle imaginary line H1 corresponds to a tangent to the second handle imaginary line H2 at the handle tip 40t. As shown in Figure 7, the first handle virtual line H1 and the second handle virtual line H2 are lines that pass through the center of the width of the teaching handle 40 when viewed from above, and exist on the same virtual plane as the second torch virtual line T2.

[0047] In this embodiment, the teaching handle 40 has a handle main body 41 and a raised portion 45. The handle main body 41 extends from a position facing the bent portion 21k of the torch main body 21 along the second handle imaginary line H2. The handle main body 41 is a curved block-shaped (stick-shaped) portion in a side view, and the upper surface 41f of the handle main body 41 is a curved surface that is aligned with the second handle imaginary line H2. Because the teaching handle 40 is curved downward, the operator can easily grip the teaching handle 40, improving the operability of the teaching handle 40. By hooking the operator's fingers, from the middle finger F3 to the ring finger F4 and the little finger F5, on the raised portion 45, the grip of the teaching handle 40 can be improved, further improving the operability of the teaching handle 40.

[0048] 3, a display panel 44, a function lever 43, and a plurality of function buttons 42 are arranged on the top surface 41f of the handle body 41 in this 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 between (a) a manual welding mode operated by the operator (worker), (b) a first teaching mode in which the operator (worker) teaches the robot body 10 a welding operation using external force, and (c) a second teaching mode in which the operator (worker) operates the function lever 43 or the like to send an operation signal to the robot body 10, thereby maneuvering the robot body 10 and teaching the robot body 10 a welding operation. The status of the robot body 10, including these modes, is displayed on a display panel 44. Furthermore, the stop button 48 is a button for forcibly stopping the welding robot 1 in an emergency, etc. The signal output by the operator operating the function button 42 and the function lever 43 is transmitted to the above-mentioned control device via a cable 49 connected to the handle base end 40p of the teaching handle 40.

[0050] Furthermore, the teaching handle 40 has a raised portion 45 that rises from the lower part of the handle body 41. The raised portion 45 is a portion for the operator to hang his / her fingers on when gripping the teaching handle 40. The height of the raised portion 45 from the handle body 41 decreases as it moves from the handle tip end 40t side to the handle base end 40p side.

[0051] An operation switch 46 is disposed on an end face 45b of the surface 45a of the raised portion 45, on the handle tip 40t side. The operation switch 46 is a switch that allows the robot body 10, whose movement is restricted, to be moved by an external force. Because the operation switch 46 is disposed on the end face of the surface of the raised portion 45 on the handle tip 40t side, the operation switch 46 can be easily pressed with the operator's index finger F2 while the operator places their fingers from middle finger F3 to little finger F5 on the raised portion 45.

[0052] Specifically, the robot body 10 is equipped with the first to sixth motors described above, and when 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 unlocking may be set to continue by continuing to press the operation switch 46, or may be set to switch between locked and unlocked by pressing the operation switch 46 once. In this way, the restriction (lock) on the movement of the robot body 10 is released, and movement of the robot body 10 is permitted.

[0053] 5. Regarding Bracket 30 3 and 6, bracket 30 has bracket body 31 that is detachably fixed to connection plug 21c of welding torch 20, and handle support portion 35 that is continuous with bracket body 31 and supports teaching handle 40 on welding torch 20. Bracket body 31 is arranged side by side with a gap in between in a first portion of torch body 21 from torch base end 21p to bent portion 21k.

[0054] In this embodiment, a fixing plate 36 made of an electrically insulating resin such as a polyolefin resin 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 protrusion 36t that engages with a recess in the connection plug 21c is formed in the center of the fixing plate 36, and a pair of locking pins 39p that are locked to the attachment / detachment tool 39 are provided on both horizontal sides of the fixing plate 36.

[0055] The bracket body 31 is a metal part made of a metal material such as aluminum or stainless steel. The bracket body 31 is fixed to a fixing plate 36 so as to surround the connection plug 21c without contacting the connection plug 21c. The bracket body 31 is formed with a cover part 31c that surrounds the connection plug 21c and a pair of flange parts 31t, 31t formed on both sides of the cover part 31c, along the first torch imaginary line T1 from the teaching handle 40 side. Each flange part 31t is provided with a through hole 31g into which an attachment / detachment tool 39 is inserted.

[0056] As a result, as shown in Fig. 7, a gap S can be formed between (the cover portion 31c of) the bracket main body 31 and the connection plug 21c. In this embodiment, the bracket main body 31 is fixed to the resin fixing plate 36 so as to surround the connection plug 21c without contacting the connection plug 21c, thereby ensuring electrical insulation between the connection plug 21c and the bracket main body 31. This prevents the operator from directly touching the welding torch 20 and ensures electrical insulation between the welding torch 20 and the teaching handle 40.

[0057] The bracket main body 31 is detachably fixed to the connection plug 21c by a detachable tool 39 with a push button 39b via a fixing plate 36 fixed to the connection plug 21c. The detachable tool 39 releases the engagement between the fixing plate 36 and the bracket main body 31 when the push button 39b is pressed. The detachable tool 39 is attached to the bracket main body 31 and the fixing plate 36 so that the push button 39b is pressed in the direction from the bracket main body 31 side relative to the fixing plate 36.

[0058] For example, an example of such an attachment / detachment device 39 is a device known as a one-way clamper. Specifically, as shown in FIG. 7 , the attachment / detachment device 39 includes a cylindrical housing 39a. Housing 39a accommodates a movable body 39t that moves along the axial direction of housing 39a and a biasing spring 39s that biases a push button 39b. Movable body 39t has a shape that is narrowed in the axial direction. Push button 39b slidably covers movable body 39t, and a plurality of retraction balls 39k that retract movable body 39t are arranged around the axis on the end face of push button 39b. Furthermore, inside housing 39a, a plurality of locking balls 39j that lock onto locking pins 39p are arranged around the axis on the tip side of movable body 39t.

[0059] When attaching the bracket bodies 31 to the fixing plate 36, the flanges 31t of each bracket body 31 are brought into contact with the fixing plate 36, and the locking pins 39p erected on the fixing plate 36 are inserted into the housings 39a of the attachment / detachment tool 39, and the locking pins 39p are engaged with the locking balls 39j. In this way, the bracket bodies 31 are attached to the connection plug 21c by the attachment / detachment tool 39 via the fixing plates 36 fixed to the connection plug 21c.

[0060] On the other hand, when removing the bracket main body 31 from the fixing plate 36, the push button 39b is pushed in, causing the retractable ball 39k to enter the constriction of the movable body 39t. When the push button 39b is released in this state, the restoring force of the biasing spring 39s causes the push button 39b to return to its original position, and the retractable ball 39k and the movable body 39t are retracted into the push button 39b. At this time, the engagement between the locking pin 39p and the locking ball 39j is released. This allows the bracket main body 31 to be removed from the fixing plate 36 fixed to the connection plug 21c.

[0061] As described above, according to this embodiment, the detachable tool 39 is attached to the bracket body 31 and the fixed plate 36 so that the push button 39b of the detachable tool 39 is pushed in from the bracket body 31 side relative to the fixed plate 36. As a result, from the state shown in FIG. 3 , when the operator holds the teaching handle 40 with one hand H in front of the operator and pushes the push button 39b from the bracket body 31 side toward the fixed plate 36 with the fingers of the other hand, the lock by the detachable tool 39 is released. When the operator pulls the teaching handle 40 toward the operator with the push button 39b pressed in, the teaching handle 40 can be easily removed from the welding torch 20 together with the bracket body 31.

[0062] Furthermore, in this embodiment, a pair of arms 31a are formed on the bracket 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 body 21, which extends from the torch base end 21p to the bent portion 21k. This provides an opening 31w in the bracket body 31 that exposes the first portion 21a of the torch body 21, which extends from the torch base end 21p to the bent portion 21k, when viewed from the teaching handle 40 side. This allows the first portion 21a and the second portion 21b of the torch body 21 to be visually observed during manual welding and teaching operations. As a result, while visually observing the torch body 21, manual welding can be performed accurately and welding operations can be taught to the robot body 10 with high accuracy. Furthermore, the operator can insert his or her finger into the opening 31w to press the stop button 48.

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

[0064] In this embodiment, abutment portions 31b that abut against the upper and lower clamp members 33, 34 are formed at the tip (lower end) of each arm 31a of the bracket main body 31. Abutment portions 31b are formed with abutment surfaces 31f that abut against end faces 33f, 34f of the upper and lower clamp members 33, 34 toward the teaching handle 40. Abutment portions 31b are formed with insertion holes 31h through which fasteners 74, such as bolts, that are fastened to the upper and lower clamp members 33, 34 are inserted. Each of the upper clamp member 33 and the lower clamp member 34 is attached to abutment portions 31b of the bracket main body 31 from the torch body 21 side by fastening them with fasteners 72 inserted through insertion holes 31h.

[0065] 4, in a side view, the contact surface 31f of the contact portion 31b and the end faces 33f, 34f of the pair of upper and lower clamp members 33, 34 that contact the contact surface 31f are inclined with respect to the first torch imaginary line T1. This makes it possible to prevent a shear force from acting on the thread portion of the fastener 72 in a direction perpendicular to the axial direction of the fastener 72 due to an external force applied in the vertical direction by the operator from the teaching handle 40.

[0066] The upper clamp member 33 and the 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 sandwiched from above and below, fasteners (not shown) are inserted through the four through-holes 33h of the teaching handle 40, and the fasteners are tightened to the lower clamp member 34. This allows the teaching handle 40 to be held to the welding torch 20 via the bracket 30. By making the upper and lower clamp members 33 and 34 out of resin, electrical insulation between the connection plug 21c and the teaching handle 40 is ensured. Furthermore, the upper clamp member 33 is formed with an opening window 33w corresponding to the shape of the display panel 44. The operator can perform work using the teaching handle 40 while viewing the display panel 44 through the opening window 33w.

[0067] 6. Manual welding and instruction The following describes the teaching of the welding robot 1 for manual welding and automatic welding, along with its effects. For example, in the case of manual welding, the operator (worker) sets the welding robot to manual welding mode (a) using the function button 42. When the operator presses the operation switch 46 once, the mechanical or electrical locks of the first to sixth motors are released. This allows the operator to grasp 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 using an external force (operation force) from the teaching handle 40 in accordance with the welding operation. Specifically, the control device described above controls the driving of the first to sixth motors of the robot body 10 in response to signals detected by the torque sensors of the axes attached to the robot body 10 or force sensors (not shown) that measure forces in three-dimensional directions applied to the tip of the robot body 10 due to the external force from the teaching handle 40.

[0068] In this manner, while the robot body 10 is being controlled by an external force, by pressing the operation switch 46 again with the index finger F2 during a welding operation of the robot body 10, an arc discharge is generated from the tip of the welding wire (not shown) located at the torch tip 21t, melting the wire and feeding it. This allows the operator (worker) to perform manual welding using the welding robot 1. Note that in this embodiment, the operation switch 46 is used to unlock the robot body 10 and perform a welding operation (welding by arc discharge). However, this is not a limitation, and it is sufficient to set the operation of at least one of the function button 42 and the function lever 43. For example, when the operation switch 46 is continuously pressed with the index finger F2 to release the restriction (lock) on the movement of the robot body 10 and perform a 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, if the operator (worker) sets the first teaching mode using function button 42 (b), continuing to press operation switch 46 continues to unlock the mechanical or electrical locks of motors 1 to 6. As a result, while holding teaching handle 40, the operator continues to press operation switch 46 in accordance with the welding operation, and moves torch tip 21t of welding torch 20 along the welding line while changing the posture of robot body 10 using external force (operation force) from teaching handle 40. Specifically, as described above, the control device controls the drive of motors 1 to 6 of robot body 10 in response to signals detected by the torque sensor or force sensor or the like due to the external force from teaching handle 40. At this time, the rotational positions of motors 1 to 6 are calculated based on detection signals from encoders (not shown) of motors 1 to 6. This allows the operator to teach robot body 10 a welding operation.

[0070] For example, when teaching, if the operator (worker) sets the second teaching mode (c) using the function button 42, the operator can perform teaching similar to that using a commonly known teaching pendant by operating the function lever 43, etc. Therefore, detailed explanation will be omitted.

[0071] When the above-mentioned operation switch 46 is pressed (ON state), the first to sixth motors are mechanically or electrically locked, but motors that do not need to be driven, such as the first motor, may be kept locked, for example, in accordance with the posture of the articulated robot during teaching.

[0072] According to this embodiment, while holding the teaching handle 40, the operator can apply an external force from the teaching handle 40 to the tip of the robot body 10, thereby teaching the robot body 10 to operate in accordance with the position of the torch tip 21t. Furthermore, the teaching handle 40 is attached to the welding torch 20 so that the handle tip 40t is located opposite the bent portion 21k, and the torch body 21 extends across the first torch imaginary line T1 in a direction away from the second portion 21b from the bent portion 21k to the torch tip 21t. As a result, during teaching work, the operator holds the teaching handle 40 so that the handle tip 40t is located in front of the operator, and by moving the handle tip 40t of the teaching handle 40 that the operator is holding, the torch tip 21t of the torch body 21 can be moved accurately and smoothly.

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

[0074] Therefore, during manual welding, welding robot 1 can perform welding movements similar to those of a welding worker, allowing for the formation of highly accurate welds W on workpieces P1, P2 by manual welding. Furthermore, during teaching, welding robot 1 can be taught movements similar to those of a welding worker, allowing for the formation of highly accurate welds W on workpieces P1, P2 by automatic welding. In particular, if the handle mounting angle is in the range of 110° to 140°, this is similar to the arrangement of handle-type torch body 21A and handle 40A, and therefore these effects can be expected even more effectively.

[0075] Furthermore, in this embodiment, by using the bracket 30 described above, the operator (worker) holds the teaching handle 40 so that the handle tip 40t is positioned in front of the operator during manual welding and teaching operations. 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 teaching handle 40 that he or she is holding. In particular, by positioning the torch body 21 and the teaching handle 40 so that the first handle imaginary line H1 and the second torch imaginary line T2 are on the same imaginary plane, this effect can be further enhanced.

[0076] Furthermore, bracket body 31 is detachably fixed to the connection plug, and bracket body 31 is arranged next to but spaced from first portion 21a of torch body 21, which extends from torch base end 21p to bent portion 21k. This allows the operator to apply force from teaching handle 40 to connection plug 21c via bracket body 31. Therefore, even if teaching handle 40 is attached near bent portion 21k of torch body 21, manual welding can be performed while suppressing oscillation of torch tip 21t, and welding operations can be taught to robot body 10 with high accuracy.

[0077] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various design modifications can be made without departing from the spirit of the present invention as set forth in the claims. [Explanation of symbols]

[0078] 1: welding robot, 10: robot body, 14: support arm, 20: welding torch, 21: torch body, 21a: first part, 21b: second part, 21k: bending part, 21p: torch base end, 21t: torch tip, 22: connecting part, 40: teaching handle, 40p: handle base end, 40t: handle tip, 41: handle body, 45: raised part, 45a: surface, 45b: end face, 46: operation switch, H1: first handle imaginary line, T1: first torch imaginary line, T2: second torch imaginary line, θ: handle mounting angle

Claims

1. A welding robot comprising an articulated robot body and a welding torch attached to the tip of the robot body, The welding torch includes a torch body and a connecting portion that connects the torch body to a tip of the robot body, the torch body has a bent portion formed by bending the torch body between a torch base end of the torch body and a torch tip end of the torch body, the welding robot further includes a teaching handle that is held by an operator and that teaches the robot body an operation corresponding to a position to which the torch tip is moved by an external force applied from the operator to the tip of the robot body, the teaching handle is attached to the welding torch so that a tip of the handle is disposed at a position facing the bent portion, the teaching handle extends in a direction away from a second portion of the torch body from the bent portion to the torch tip, across a first torch imaginary line along a first portion of the torch body from the torch base end to the bent portion, when the torch body and the teaching handle are viewed from the side; a handle mounting angle formed by a second torch imaginary line along a second portion of the torch body from the bent portion to the torch tip and a first handle imaginary line along a direction in which the teaching handle extends from the handle tip is an obtuse angle; The handle mounting angle is in the range of 110° to 140°, the teaching handle is detachably attached to the welding torch via a bracket, The teaching handle is a handle body extending from a position opposite the bent portion; a raised portion for a finger hook that protrudes from the lower portion of the handle body and onto which the operator's fingers are hooked when the operator is holding the teaching handle.

2. 2. The welding robot according to claim 1, wherein the teaching handle is curved downward when viewed from the side.

3. A welding robot as described in claim 1, characterized in that the height of the raised portion from the handle body decreases as it progresses from the handle tip side to the handle base end side.

4. the teaching handle is provided with an operation switch that allows the robot body, the movement of which is restricted, to be moved by the external force; 4. The welding robot according to claim 3, wherein the operation switch is disposed on an end surface of the raised portion on the tip side of the handle.

Images