Welding robot

Abstract

The present invention addresses the problem of difficulty in demonstrating a welding operation performed by a robot body with high precision due to swinging of the tip of a welding torch when a teaching handle is attached to the vicinity of a curved section of the welding torch body. A welding robot (1) is provided with a connection part (22) that connects a welding torch body (21) and a support arm (14) at the tip of a robot body (10). A holding mechanism (25) for holding the welding torch base end (21p) via the connection plug (21c) is provided so that the welding torch tip (21t) is swingable with respect to the connection section. The teaching handle (40) is attached to the welding torch (20) via the bracket (30). The bracket is provided with: a bracket main body which is detachably fixed to the connection plug and which is provided in parallel with a first portion of the torch main body from the torch base end to the bent portion at a distance from the torch base end to the bent portion; and a handle supporting part which supports the teaching handle in a manner that the handle front end of the teaching handle is configured at a position opposite to the bending part.

Description

Technical Field

[0001] The invention relates to a welding robot. Background Art

[0002] In recent years, collaborative robots configured to operate near an operator have been developed. For example, Patent Document 1 proposes a robot having a hand for holding a component at the front end of the robot body. In this robot, a teaching handle for teaching the robot's operation is installed at the front end of the robot body. The teaching handle is used to teach the robot's operation corresponding to the movement position of the hand by means of an operating force applied from the operator to the front end of the robot body while being held by the operator.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-199174 Summary of the invention

[0006] Problems to be solved by the invention

[0007] However, in the case where a robot equipped with such a teaching handle is used as a welding robot, since the teaching handle is installed at the front end of the robot, the position of the teaching handle is far away from the welding torch body of the welding torch. Therefore, it is also considered to install the teaching handle directly on the curved part (bend) of the welding torch body. However, a holding mechanism is provided at the base end of the welding torch to hold the welding torch body, so that when the front end of the welding torch contacts the outside, the front end of the welding torch swings, thereby releasing the force acting on the welding torch body. Therefore, in the teaching operation, when the operating force is to be applied to the welding torch body via the teaching handle, the torque acts on the welding torch body in a manner that causes the front end of the welding torch to swing, making it difficult to teach the welding action to the robot body with high precision.

[0008] The present invention has been made in view of such a situation, and its object is to provide a welding robot which can suppress the swing of the front end of the welding torch and teach the welding action to the robot body with high accuracy even if the teaching handle is installed near the curved portion of the welding torch body.

[0009] Solutions to Solve Problems

[0010] In view of the above-mentioned problem, the welding robot involved in the present invention comprises a robot body with multiple joints and a welding torch installed at the front end of the robot body, the welding robot is characterized in that the welding torch comprises a welding torch body and a connecting portion connecting the welding torch body to the front end of the robot body, the welding torch body has a bending portion between the welding torch base end of the welding torch body and the welding torch front end of the welding torch body, the connecting portion has a holding mechanism for holding the welding torch base end via a connecting plug so that the welding torch front end can swing freely relative to the connecting portion, and the welding robot also A teaching handle is provided, which, when held by an operator, teaches the movement of the robot body corresponding to the moving position of the front end of the welding torch by means of an operating force applied by the operator to the front end of the robot body, wherein the teaching handle is mounted on the welding torch via a bracket, and the bracket comprises: a bracket body, which is fixed to the connecting plug in a detachable manner and is arranged in parallel with a first portion of the welding torch body from the base end of the welding torch to the bending portion at a distance therefrom; and a handle support portion, which supports the teaching handle in such a manner that the front end of the handle of the teaching handle is arranged at a position opposite to the bending portion.

[0011] According to the present invention, the operator can impart operating force from the teaching handle to the front end of the robot body while holding the teaching handle, thereby teaching the movement of the robot body corresponding to the moving position of the front end of the welding torch. In the present invention, the support portion of the bracket supports the teaching handle on the welding torch body in such a manner that the front end of the handle of the teaching handle is arranged at a position opposite to the bending portion. Thus, during the teaching operation, the operator can hold the teaching handle in such a manner that the front end of the handle is located in front of the operator and move the front end of the handle of the held teaching handle, thereby accurately and smoothly moving the front end of the welding torch of the welding torch body.

[0012] Furthermore, the bracket body is fixed to the connection plug in a detachable manner, and the bracket body is arranged in parallel with the first part of the welding torch base end to the bending part in the welding torch body at a distance. Thus, the force of the operator acts on the connection plug from the teaching handle via the arm part, so even if the teaching handle is installed near the bending part of the welding torch body, the swing of the front end of the welding torch can be suppressed and the welding action can be taught to the robot body with high accuracy.

[0013] As a more preferred embodiment, a fixing plate made of resin is fixed to the connection plug, and the bracket body is fixed to the fixing plate so as to surround the connection plug without contacting the connection plug.

[0014] According to this aspect, the bracket body is fixed to the resin support plate in a manner surrounding the connection plug without contacting the connection plug, so that electrical insulation between the connection plug and the bracket body can be ensured. Thus, insulation between the welding torch and the teaching handle can be ensured.

[0015] As a more preferred embodiment, when the welding torch body and the teaching handle are observed from the side, the teaching handle extends in a direction away from the bending portion to the second portion to the front end of the welding torch, clamping a first welding torch imaginary line along the first portion from the base end of the welding torch to the bending portion in the welding torch body, and the bracket body is fixed to the connecting plug via the fixing plate by a loading and unloading part with a push-in button in a freely loadable and unloadable manner, and the loading and unloading part releases the locking of the fixing plate and the bracket body by pressing the push-in button, and the loading and unloading part is installed on the bracket body and the fixing plate in such a manner that the pressing direction of the push-in button becomes the pressing direction from the bracket body side relative to the fixing plate.

[0016] According to this scheme, during the teaching operation, the operator can hold the teaching handle in such a manner that the front end of the handle is located in front of the operator and move the front end of the held teaching handle, thereby accurately and smoothly moving the front end of the welding torch of the welding torch body. In addition, the loading and unloading parts are installed on the bracket body and the fixed plate in such a manner that the pressing direction of the push button becomes the pressing direction from the bracket body side relative to the fixed plate. Thus, when the push button is pressed from the bracket body side toward the fixed plate with the fingers of the other hand of the operator while holding the teaching handle in front of the operator with one hand, the locking of the fixed plate and the bracket body is released. When the teaching handle is pulled close to the operator with the push button pressed, the teaching handle can be easily removed from the welding torch together with the bracket body.

[0017] As a more preferred embodiment, the bracket body is formed with an opening that exposes a portion of the torch body from the torch base end to the first portion of the bent portion when the torch body is viewed from the teaching handle side.

[0018] According to this solution, an opening is formed in the welding torch body to expose the first part from the welding torch base end to the curved part, so that the first part and the second part of the welding torch body can be visually identified during the teaching operation. Thus, the welding action can be taught to the robot body with high accuracy while visually identifying the welding torch body.

[0019] As a more preferred embodiment, the bracket body is made of metal, the handle support portion is made of resin, and the handle support portion includes a pair of clamping members for clamping the teaching handle.

[0020] According to this aspect, the teaching handle can be fixed to the bracket body in a state where the teaching handle is sandwiched by the pair of clamping members. By making the pair of clamping members made of resin, electrical insulation between the connection plug and the teaching handle can be ensured.

[0021] Effects of the Invention

[0022] According to the present invention, even if the teaching handle is attached near the curved portion of the welding torch body, it is possible to suppress the swing of the welding torch tip and teach the robot body a welding operation with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic perspective view of the welding robot according to the embodiment of the present invention as viewed from the front.

[0024] Figure 2 From the rear Figure 1 A three-dimensional image of the welding robot shown.

[0025] Figure 3 Yes Figure 1 The schematic three-dimensional diagram shown is for explaining the installation state of the teaching handle of the welding robot.

[0026] Figure 4 yes Figure 3 A side view of the welding robot is shown.

[0027] Figure 5 yes Figure 4 A partial cross-sectional view of a welding robot is shown.

[0028] Figure 6 yes Figure 2 An exploded perspective view of the welding robot shown.

[0029] Figure 7 It is along Figure 5 The cross-sectional view is obtained along the AA line shown.

[0030] Figure 8 (a) is used for Figure 4 The side view of the welding robot is shown to illustrate the teaching operation. Figure 8 (b) is a side view for explaining welding work performed using a handle-type welding torch.

[0031] Description of Reference Numerals

[0032] 1: welding robot, 10: robot body, 14: support arm, 20: welding torch, 21: welding torch body, 21a: first part, 21b: second part, 21c: connection plug, 21k: bending part, 21p: welding torch base end, 21t: welding torch front end, 22: connecting part, 25: holding mechanism, 30: bracket, 30w: opening part, 31: bracket body, 33: upper clamping member, 34: lower clamping member, 35: handle support part, 36: fixing plate, 39: loading and unloading part, 39b: button, 40: teaching handle, 40t: handle front end, K1: first welding torch imaginary line. DETAILED DESCRIPTION

[0033] Below, refer to Figures 1 to 8 A welding robot 1 according to this embodiment of the present invention will be described.

[0034] 1. About welding robots 1

[0035] like Figure 1 as well as Figure 2 As shown, the welding robot 1 includes a multi-jointed robot body 10, a welding torch 20 mounted on a support arm 14 at the front end of the robot body 10, and a teaching handle 40 mounted on the welding torch 20 via a bracket 30. The welding torch 20 corresponds to an end effector of the robot body 10.

[0036] In the present embodiment, the welding robot 1 is a collaborative robot configured to operate near an operator. Specifically, the welding robot 1 has a direct teaching function for an operator as an operator to teach welding operations. Specifically, the direct teaching function is a function in which, when the operator holds the teaching handle 40, an external force (operating force) from the operator is directly applied to the front end of the robot body 10 by means of the teaching handle 40, thereby changing the posture of the robot body 10 and teaching the welding operation to the robot body 10. In addition, the welding robot 1 also has a function for the operator to perform manual welding using the teaching handle 40 before the formal welding is performed by the welding robot 1.

[0037] 2. About the robot body 10

[0038] like Figure 1 as well as Figure 2 As shown, the robot body 10 includes a base 11 installed on an installation surface. The base 11 includes a fixed table 11a fixed to the installation surface and a rotating table 11b rotating around a first axis J1 along a direction perpendicular to the installation surface.

[0039] The rotating table 11b is connected to the output shaft of the first motor (not shown) fixed to the fixed table 11a. Thus, the rotating table 11b can be rotated around the first axis J1 relative to the fixed table 11a by driving the first motor. A first reducer (not shown) is installed on the output shaft of the first motor, and a first torque sensor (not shown) for detecting the torque around the first axis J1 is installed on the output shaft of the first reducer. It should be noted that the first motor, the first reducer and the first torque sensor are accommodated inside the base 11.

[0040] The robot body 10 has a lower arm 12 whose base end is pivoted to the rotating table 11b, an upper arm 13 pivoted to the front end of the lower arm 12, and a support arm 14 pivoted to the front end of the upper arm 13. These arms are made of metal, such as cast iron or alumina alloy casting.

[0041] The base end axis of the lower arm 12 is supported on the turntable 11b of the base 11, and is pivotally connected to the turntable 11b via a second motor (not shown) in a manner that it can rotate freely around the second axis J2. Here, the second axis J2 is an axis parallel to a direction orthogonal to the first axis J1. With the help of the power of the second motor, the lower arm 12 rotates around the second axis J2 relative to the turntable 11b. A second reducer (not shown) is installed on the output shaft of the second motor. A second torque sensor (not shown) for detecting the torque around the second axis J2 is installed on 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 in shape, and various cables (not shown) are passed through the inside.

[0042] The front end of the lower arm 12 is axially supported on the upper arm 13, and the upper arm 13 is pivotally connected to the third axis J3 parallel to the second axis J2 in a freely rotatable manner via a third motor (not shown). The third motor is fixed to the upper arm 13 in the upper arm 13. A third reducer is installed on the output shaft of the third motor. In addition, a third torque sensor for detecting torque around the third axis J3 is installed on the output shaft of the third reducer, and the third torque sensor is fixed to the lower arm 12.

[0043] The upper arm 13 is equivalent to the arm part of the robot body 10, and a third motor and a fourth motor (not shown) are housed therein. The output shaft of the fourth motor is connected to the arm body of the upper arm 13 via a power transmission belt, etc., and a fourth torque sensor for detecting torque around the fourth axis J4 is installed on 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 long side direction of the arm body.

[0044] The front end of the upper arm 13 is a portion corresponding to the wrist of the robot body 10, and is provided with a support arm 14 for supporting the welding torch 20. Specifically, the support arm 14 is pivotally connected to the front end of the upper arm 13 so as to be rotatable about a fifth axis J5 orthogonal to the fourth axis J4, and is rotatable about a sixth axis J6 along the longitudinal direction.

[0045] A fifth motor (not shown) is built into the upper arm 13 to pivot the support arm 14 relative to the upper arm 13. The fifth motor is connected to the support arm 14 via a power transmission belt built into the upper arm 13 or the like. It should be noted that the fifth motor and the 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 thus the support arm 14 rotates (sways) relative to the upper arm 13 due to the fifth axis J5.

[0046] In addition, 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). Thus, the front end (main body) of the support arm 14 can be rotated around the axis (specifically, the sixth axis J6) by the drive of the sixth motor.

[0047] As described above, in the present embodiment, the robot body 10 includes first to sixth motors for driving around the axes J1 to J6. The robot body 10 also includes first to fourth torque sensors for measuring the torque acting on the axes J1 to J4. The first to fourth torque sensors are strain gauge torque sensors.

[0048] Here, the welding robot 1 can measure the torque around the fifth axis J5 and the torque around the sixth axis J6 by a torque sensor, but can also estimate the torque based on the current flowing through the fifth motor and the sixth motor by using a control device (not shown), for example.

[0049] The welding robot 1 includes a control device and a welding machine (not shown). The control device controls the movement of the welding robot 1 by controlling the driving of the first to sixth motors. The control device controls the welding robot 1 by (1) controlling the welding movement of the robot body 10, (2) controlling the feeding speed of a feeding device that feeds welding wire to the welding torch 20, which constitutes the welding machine body (not shown), (3) controlling the voltage applied to the welding torch 20 for welding, and (4) controlling the supply timing of the shielding gas supplied to the welding torch 20. More specifically, as the control device of the welding robot 1, the control device controls manual welding of the welding robot 1 for performing welding such as temporary welding using the teaching handle 40 performed by an operator, controls teaching of the welding robot 1 for teaching by external operation (operation based on external force) performed by the teaching handle 40, and controls automatic welding of the welding robot 1 corresponding to the taught movement.

[0050] 3. About Torch 20

[0051] The welding torch 20 includes a welding torch body 21 and a connection portion 22 connecting the welding torch body 21 to the support arm 14 at the front end of the robot body 10. The welding torch body 21 has a bent portion 21k formed by bending the welding torch body 21 between the welding torch base end 21p and the welding torch front end 21t.

[0052] Specifically, the first portion 21a from the base end 21p of the welding torch to the curved portion 21k of the welding torch body 21 is formed along the first straight welding torch imaginary line T1. The second portion 21b from the curved portion 21k to the front end 21t of the welding torch body 21 is formed along the second straight welding torch imaginary line T2. The first welding torch imaginary line T1 and the second welding torch imaginary line T2 pass through the axis of the first portion 21a and the second portion 21b of the welding torch body 21, respectively, and the angle formed by them is 135° in the present embodiment, which is within the range of 120° to 150°.

[0053] The welding torch body 21 is provided with a path for passing a welding wire, a gas flow path for supplying a shielding gas, and the like, and a nozzle is installed on the second portion 21b of the welding torch body 21. The structure of the welding torch body 21 is a common structure, so a detailed description is omitted. In addition, the first portion 21a of the welding torch body 21 is connected to the connection plug 21c at the welding torch base end 21p of the welding torch body 21. The connection plug 21c is connected with a wiring (not shown) for applying a voltage for welding to the welding torch body 21, a pipe (not shown) for supplying a shielding gas for welding, and the like.

[0054] like Figure 5As shown, the connection part 22 has a holding mechanism 25 for holding the torch base end 21p via a connection plug 21c so that the torch tip 21t can swing freely relative to the connection part 22. A holding rod 25a constituting 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.

[0055] The end of the holding rod 25a has a dish-shaped head 25f, and the head 25f is housed in a housing 25h constituting the holding mechanism 25 so that the holding rod 25a can swing freely. The shaft portion of the holding rod 25a and a part of the connecting plug 21c are covered by a flexible rubber cover 25c together with the lower end of the housing 25h. As a result, the welding torch tip 21t can swing freely relative to the housing 25h together with the holding rod 25a.

[0056] The housing 25h contains a movable member 25d that contacts the convex surface of the head 25f of the holding rod 25a. The movable member 25d is arranged in the housing 25h so as to be movable along the long side direction of the housing 25h (the direction along the first welding torch virtual line T1). The housing 25h is provided with a biasing spring 25s that biases the movable member 25d toward the head 25f of the holding rod 25a.

[0057] By configuring in this way, the torch body 21 is held together with the holding rod 25a. Figure 5 When external force acts on the front end 21t of the welding torch body 21, the holding rod 25a swings, the movable part 25d abutting against the convex surface of the head 25f is pushed up, and the force spring 25s is compressed. When the external force on the front end 21t of the welding torch is released, the movable part 25d is pressed down due to the restoring force of the force spring 25s, and the welding torch body 21 and the holding rod 25a return to the original position. Figure 5 It should be noted that when the movable member 25d is pushed up to the uppermost limit, the limit switch 25p is activated and the welding is interrupted.

[0058] In this way, the damage of the welding torch body 21 caused by the external force acting on the welding torch front end 21t can be prevented. It should be noted that in the present embodiment, the holding mechanism 25 uses the biasing spring 25s to hold the posture of the welding torch body 21, but for example, a magnet may be installed in the portion corresponding to the holding rod 25a and a magnet may be installed in the portion corresponding to the movable part 25d, and the posture of the welding torch body 21 may be held to be swingable by the magnetic force of the two magnets.

[0059] It should be noted that the axis of the force spring 25s, the movable member 25d and the holding rod 25a forms a through portion penetrating along the first welding torch imaginary line T1 from the upper part of the housing 25h, and the welding wire for welding is fed along the through portion during welding. In addition, in the present embodiment, the housing 25h of the holding mechanism 25 is fixed to the support arm 14 of the robot body 10 through the L-shaped reinforcing angle iron 26 and the connector 27 by fastening the connecting members 71, 72, etc. Specifically, the welding torch 20 is mounted on the support arm 14 in such a manner that the sixth axis J6 of the support arm 14 is parallel to the first welding torch imaginary line T1.

[0060] 4. About the teaching handle 40 and its installation status

[0061] The welding robot 1 teaches the operation of the robot body 10 according to the movement position of the welding torch tip 21 t by the external force applied from the operator to the tip of the robot body 10 while the teaching handle 40 is held by the operator.

[0062] like Figure 4 As shown, the teaching handle 40 is mounted on the welding torch 20 in such a manner that the handle front end (front end surface) 40t is arranged at a position opposite to the curved portion 21k of the welding torch body 21. Specifically, the teaching handle 40 is detachably mounted on the welding torch 20 via the bracket 30. When performing automatic welding by the welding robot 1, the teaching handle 40 is removed from the welding torch 20 except for the fixing plate 36 together with the bracket 30.

[0063] Here, if Figure 4 As shown, the torch body 21 and the teaching handle 40 are observed from the side in a state where the teaching handle 40 is supported by the handle support portion 35. In this side view, the teaching handle 40 extends in a direction away from the bending portion 21k to the second portion 21b of the torch tip 21t, sandwiching the first torch imaginary line T1 along the first portion 21a of the bending portion 21k of the torch body 21 from the torch base end 21p.

[0064] Specifically, the handle installation angle θ formed by the second torch imaginary line T2 along the curved portion 21k of the torch body 21 to the second portion 21b of the torch front end 21t and the first handle imaginary line H1 along the direction extending from the handle front end 40t of the teaching handle 40 is an obtuse angle. The handle installation angle θ is preferably within the range of 110° to 140′. Figure 4It can be seen that when the teaching handle 40 is observed from the side, the teaching handle 40 is bent downward from the handle front end 40t toward the handle base end 40p. Specifically, the teaching handle 40 is bent from the handle front end 40t toward the handle base end 40p along the arc-shaped second handle virtual line H2, and the straight first handle virtual line H1 is equivalent to the tangent of the second handle virtual line H2 of the handle front end 40t. It should be noted that Figure 7 As shown, the first handle virtual line H1 and the second handle virtual line H2 are lines passing through the center of the teaching handle 40 in the width direction when viewed from above, and exist on the same virtual plane as the second torch virtual line T2.

[0065] In the present embodiment, the teaching handle 40 has a handle body 41 and a raised portion 45. The handle body 41 extends from an opposing position opposite to the bent portion 21k of the welding torch body 21 along the second handle imaginary line H2. The handle body 41 is a curved block-shaped (rod-shaped) portion when viewed from the side, and the upper surface 41f of the handle body 41 is a curved surface that is curved parallel to the second handle imaginary line H2. The teaching handle 40 is bent downward, so it is easy for the operator to hold the teaching handle 40, thereby improving the operability of the teaching handle 40. By placing the operator's middle finger F3, ring finger F4, and little finger F5 on the raised portion 45, the grip of the teaching handle 40 can be improved, thereby further improving the operability of the teaching handle 40.

[0066] like Figure 3 As shown, a display panel 44, a function lever 43, and a plurality of function buttons 42 are arranged in order from the handle front end 40t side on the upper surface 41f of the handle body 41. A stop button 48 is mounted on the end surface of the handle front end 40t.

[0067] The function button 42 is a switch for switching between (a) a manual welding mode performed by an operator (worker), (b) a first teaching mode for teaching the robot body 10 a welding action with the help of an external force performed by the operator (worker), and (c) a second teaching mode for teaching the robot body 10 a welding action by sending an operation signal to the robot body 10 through an operation of the function lever 43 performed by the operator (worker) and manipulating the robot body 10. The state of the robot body 10 including such modes is displayed on the display panel 44. In addition, the stop button 48 is a button for forcibly stopping the welding robot 1 in an emergency or the like. Using such function buttons 42 and function levers 43, the signal output by the operator's operation is sent to the above-mentioned control device via the cable 49 connected to the handle base end 40p of the teaching handle 40.

[0068] Furthermore, the teaching handle 40 includes a raised portion 45 raised from the lower portion of the handle body 41. The raised portion 45 is a finger resting portion for the operator to rest his fingers on when the operator holds the teaching handle 40. The height of the raised portion 45 from the handle body 41 decreases as it moves from the handle front end 40t side toward the handle base end 40p side.

[0069] An operation switch 46 is arranged on an end surface 45b on the handle front end 40t side of the surface 45a of the raised portion 45. The operation switch 46 is a switch that allows the robot body 10 to move with the aid of an external force with respect to the robot body 10 whose movement is restricted. Since the operation switch 46 is arranged on the end surface on the handle front end 40t side of the surface of the raised portion 45, the operation switch 46 can be easily pressed by the operator's index finger F2 while the operator's middle finger F3 to little finger F5 are placed on the raised portion 45.

[0070] Here, specifically, the first to sixth motors are installed on the robot body 10, and when the operation switch 46 is not pressed (closed state), the first to sixth motors are mechanically locked or electrically locked. When the operation switch 46 is pressed (opened state), the mechanical lock or electrical lock of the first to sixth motors is released. Here, the release of the lock can be set to be continuous by continuously pressing the operation switch 46, and can also be set to switch between locking 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, thereby allowing the movement of the robot body 10.

[0071] 5. About bracket 30

[0072] like Figure 3 as well as Figure 6 As shown, the bracket 30 includes a bracket body 31 detachably fixed to the connection plug 21c of the welding torch 20, and a handle support portion 35 connected to the bracket body 31 and supporting the teaching handle 40 on the welding torch 20. The bracket body 31 is arranged in parallel with a first portion of the welding torch body 21 from the welding torch base end 21p to the bent portion 21k at a distance.

[0073] In this embodiment, a fixing plate 36 made of an insulating resin such as a polyolefin resin is fixed to the connection plug 21c as a material having electrical insulation. Figure 6 As shown, a pair of through holes 36h are formed in the fixing plate 36, and the fixing plate 36 is mounted on the connection plug 21c of the welding torch 20 through a pair of fastening members 78. A convex portion 36t engaging with a concave portion of the connection plug 21c is formed in the center of the fixing plate 36, and a pair of locking pins 39p engaging with the attachment and detachment member 39 are erected on both sides of the fixing plate 36 in the horizontal direction.

[0074] 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 the fixing plate 36 in a manner of surrounding the connection plug 21c without contacting the connection plug 21c. The bracket body 31 is provided with a cover 31c surrounding the connection plug 21c and a pair of flanges 31t, 31t formed on both sides of the cover 31c along the first welding torch virtual line T1 from the teaching handle 40 side. A through hole 31g for inserting the attachment member 39 is provided in each flange 31t.

[0075] The result is that, Figure 7 As shown, a gap S can be formed between the bracket body 31 (the cover portion 31c) and the connection plug 21c. In the present embodiment, the bracket body 31 is fixed to the resin fixing plate 36 in a manner that surrounds the connection plug 21c without contacting the connection plug 21c, so that electrical insulation between the connection plug 21c and the bracket body 31 can be ensured. Thus, it is possible to avoid the operator from directly contacting the welding torch 20, and to ensure electrical insulation between the welding torch 20 and the teaching handle 40.

[0076] The bracket body 31 is fixed to the connection plug 21c via the fixing plate 36 fixed to the connection plug 21c by a detachable member 39 having a push button 39b. The detachable member 39 releases the locking of the fixing plate 36 and the bracket body 31 by pressing the push button 39b. The detachable member 39 is attached to the bracket body 31 and the fixing plate 36 in such a manner that the pressing direction of the push button 39b is the pressing direction from the bracket body 31 side relative to the fixing plate 36.

[0077] For example, as such a detachable member 39, a detachable member called a so-called one-way clamp can be cited. Figure 7 As shown, the loading and unloading member 39 has a cylindrical housing 39a, and a movable body 39t movable along the axial direction of the housing 39a and a force spring 39s for applying force to the push button 39b are housed in the housing 39a. The movable body 39t is shaped to be tapered in the middle along the axial direction. The push button 39b covers the movable body 39t in a sliding manner, and a plurality of lead-in balls 39k for leading the movable body 39t are arranged around the axis on the end face of the push button 39b. In addition, a plurality of locking balls 39j that are locked with the locking pin 39p are arranged around the axis on the front end side of the movable body 39t in the housing 39a.

[0078] When the bracket body 31 is mounted on the fixing plate 36, the flange 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 receiving body 39a of the detachable member 39, so that the locking ball 39j is locked by the locking pin 39p. Thus, the bracket body 31 is mounted on the connection plug 21c by the detachable member 39 via the fixing plate 36 fixed to the connection plug 21c.

[0079] On the other hand, when the bracket body 31 is removed from the fixed plate 36, the ball 39k is introduced into the narrowed portion of the movable body 39t by pressing the push button 39b. If the push button 39b is released from being pressed in this state, the push button 39b returns to its original position due to the restoring force of the biasing spring 39s, and the ball 39k and the movable body 39t are introduced into the push button 39b. At this time, the locking of the locking pin 39p and the locking ball 39j is released. Thus, the bracket body 31 can be removed from the fixed plate 36 fixed to the connection plug 21c.

[0080] As described above, according to the present embodiment, the detachable member 39 is attached to the bracket body 31 and the fixing plate 36 in such a manner that the pressing direction of the pressing button 39b of the detachable member 39 becomes the pressing direction from the bracket body 31 side with respect to the fixing plate 36. Figure 3 In the state shown, when the operator holds the teaching handle 40 in front of the operator with one hand H, and the operator pushes the push button 39b from the bracket body 31 side toward the fixing plate 36 with the finger of the other hand, the locking by the attachment and detachment member 39 is released. When the teaching handle 40 is pulled close to the operator with the push button 39b pushed, the teaching handle 40 can be easily removed from the welding torch 20 together with the bracket body 31.

[0081] Furthermore, in the present embodiment, a pair of arms 31a are formed in the bracket body 31. Specifically, the arms 31a extend from both sides of the cover part 31c in a manner of being arranged in parallel with the first part 21a from the base end 21p of the welding torch to the curved part 21k in the welding torch body 21. Thus, an opening 31w is formed in the bracket body 31 to expose the first part 21a from the base end 21p of the welding torch to the curved part 21k in the welding torch body 21 when the welding torch body 21 is observed from the teaching handle 40 side. Thus, the first part 21a and the second part 21b of the welding torch body 21 can be visually recognized during manual welding and teaching operations. As a result, manual welding can be performed with high precision while visually recognizing the welding torch body 21, and welding operations can be taught to the robot body 10 with high precision. Furthermore, it is also possible to pass the operator's finger through the opening 31w and press the stop button 48.

[0082] The handle support portion 35 is a portion made of an insulating resin such as a polyolefin resin that supports the teaching handle 40 so that the handle front end 40t of the teaching handle 40 is arranged at a position opposite to the curved portion 21k. In the present embodiment, the handle support portion 35 includes an upper clamping member 33 and a lower clamping member 34 (a pair of clamping members 33, 34) that clamp the front end side of the teaching handle 40.

[0083] In the present embodiment, abutting portions 31b are formed at the front ends (lower ends) of the arms 31a of the bracket body 31, which abut against the upper and lower clamping members 33 and 34. Abutting surfaces 31f are formed at the abutting portions 31b, which abut against the end surfaces 33f and 34f of the upper and lower clamping members 33 and 34 toward the teaching handle 40 side. Insertion holes 31h are formed at the abutting portions 31b, through which fastening members 74 such as bolts fastened to the upper and lower clamping members 33 and 34 are passed. The upper clamping member 33 and the lower clamping member 34 are fastened to the fastening members 72 passing through the insertion holes 31h, respectively, from the torch body 21 side, and are thereby mounted on the abutting portions 31b of the bracket body 31.

[0084] like Figure 4 As shown, in a side view, the abutting surface 31f of the abutting portion 31b and the end surfaces 33f and 34f of the pair of upper and lower clamping members 33 and 34 abutting therewith are inclined relative to the first welding torch virtual line T1. Thus, it is possible to suppress the shear force from acting on the threaded portion of the fastening member 72 in a direction orthogonal to the axial direction of the fastening member 72 due to the external force in the up-down direction of the operator acting from the teaching handle 40.

[0085] The upper clamping member 33 and the lower clamping member 34 are formed with recessed portions 33r and 34r corresponding to the teaching handle 40. When the teaching handle 40 is installed, the upper clamping member 33 and the lower clamping member 34 are clamped from the upper and lower directions, and a fastening member (not shown) is inserted from the four through holes 33h of the upper clamping member 33, and the fastening member is screwed into the lower clamping member 34. In this way, the teaching handle 40 can be held on the welding torch 20 via the bracket 30. By making the upper and lower clamping members 33 and 34 made of resin, electrical insulation between the connection plug 21c and the teaching handle 40 can be ensured. In addition, an opening window 33w corresponding to the shape of the display panel 44 is formed in the upper clamping member 33. The operator can use the teaching handle 40 while viewing the display panel 44 through the opening window 33w.

[0086] 6. About manual welding and teaching

[0087] Hereinafter, the teaching of the welding robot in manual welding and automatic welding using the welding robot 1 and its effect will be described. For example, in the case of manual welding, (a) the operator (worker) sets the manual welding mode through the function button 42. Once the operator presses the operation switch 46, the mechanical lock or electrical lock of the first to sixth motors is released. Thus, the operator can hold the teaching handle 40, cooperate with the welding action, change the posture of the robot body 10 with the external force (operating force) from the teaching handle 40, and move the welding torch front end 21t of the welding torch body 21 along the welding line. Specifically, the control device controls the drive of the first to sixth motors of the robot body 10 with the external force from the teaching handle 40 and based on the signals detected by the torque sensors installed on each axis of the robot body 10, or the force sensors (not shown) that measure the forces in the three-dimensional directions applied to the front end of the robot body 10.

[0088] In this way, the robot body 10 is manipulated by an external force, and the operation switch 46 is pressed again with the index finger F2 during the welding action of the robot body 10, so that arc discharge is generated from the front end of the welding wire (not shown) located at the front end 21t of the welding torch to melt the welding wire and feed the welding wire. As a result, manual welding using the welding robot 1 can be performed by the operator (worker). It should be noted that in the present embodiment, the robot body 10 is unlocked and the welding action (welding based on arc discharge) is performed by the operation switch 46, but it is not limited to such a usage method, as long as the usage method of at least one of the function button 42 and the function lever 43 is set. For example, it is also possible to release the movable restriction (lock) of the robot body 10 by continuously pressing the operation switch 46 with the index finger F2, and when performing the welding action, for example, at least one of the function button 42 and the function lever 43 is operated with the thumb F1.

[0089] For example, during teaching, when the operator (worker) sets the first teaching mode through the function button 42 (b), when the operation switch 46 is continuously pressed, the mechanical lock or electrical lock of the first to sixth motors is continuously released. Thus, the operator holds the teaching handle 40 while continuously pressing the operation switch 46 in coordination with the welding action, and changes the posture of the robot body 10 with the help of the external force (operating force) from the teaching handle 40, and moves the welding torch tip 21t of the welding torch 20 along the welding line. Specifically, as described above, with the help of the external force from the teaching handle 40 and based on the signal detected by the above-mentioned torque sensor or force sensor, the above-mentioned control device controls the drive of the first to sixth motors of the robot body 10. At this time, the rotational position of the first to sixth motors is calculated using the detection signal of the encoder (not shown) of the first to sixth motors. Thus, it is possible to teach the welding action of the robot body 10 based on the operator.

[0090] For example, when teaching, if (c) the operator sets the second teaching mode via the function button 42, the operator can perform the same teaching as that performed by a generally known teaching pendant by operating the function lever 43. Therefore, detailed description is omitted.

[0091] It should be noted that when the above-mentioned operating switch 46 is pressed (open), the first to sixth motors are mechanically locked or electrically locked, but for example, depending on the posture of the multi-joint robot being taught, motors such as the first motor that do not need to be driven maintain a locked state.

[0092] According to the present embodiment, the operator can impart external force from the teaching handle 40 to the front end of the robot body 10 while holding the teaching handle 40, thereby teaching the movement of the robot body 10 corresponding to the moving position of the welding torch front end 21t. Furthermore, the teaching handle 40 is mounted on the welding torch 20 in such a manner that the handle front end 40t is arranged at a position corresponding to the curved portion 21k, and the welding torch body 21 extends in the direction away from the curved portion 21k to the second portion 21b of the welding torch front end 21t, sandwiching the first welding torch virtual line T1. Thus, during the teaching operation, the operator can accurately and smoothly move the welding torch front end 21t of the welding torch body 21 by holding the teaching handle 40 in such a manner that the handle front end 40t is located in front of the operator and moving the handle front end 40t of the held teaching handle 40.

[0093] In particular, Figure 8 As shown in (a), since the handle installation angle θ formed by the second welding torch imaginary line T2 and the first handle imaginary line H1 is an obtuse angle, Figure 8The configuration of the handle-type torch body 21A and the handle 41A for manual welding shown in (b) is similar. 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) and Figure 8 The handle mounting angle θ shown in (a) is close to that of FIG. 1. In addition, 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, so the operation switch 46 can be pressed by the index finger of the operator.

[0094] Therefore, during manual welding, the welding robot 1 can perform welding close to the movements of the operator performing welding, so that a high-precision weld W can be formed with respect to the welded members P1 and P2 by manual welding. Furthermore, during teaching, the welding robot 1 can be taught to perform movements close to the movements of the operator performing welding, so that a high-precision weld W can be formed with respect to the welded members P1 and P2 by automatic welding. In particular, if the handle mounting angle is within the range of 110° to 140°, the configuration state of the handle-type welding torch body 21A and the handle 40A is close to that of the handle type, so such an effect can be further expected.

[0095] Furthermore, in the present embodiment, by using the above-mentioned bracket 30, during manual welding and teaching operations, the operator (worker) holds the teaching handle 40 in such a manner that the handle front end 40t is located in front of the operator. Furthermore, the operator can accurately and smoothly move the welding torch front end 21t of the welding torch body 21 by moving the handle front end 40t of the held teaching handle 40. In particular, by configuring the welding torch body 21 and the teaching handle 40 in such a manner that the first handle virtual line H1 and the second welding torch virtual line T2 are located on the same virtual plane, such an effect can be further exerted.

[0096] The bracket body 31 is fixed to the connection plug in a detachable manner, and is separately arranged in parallel with the first portion 21a from the base end 21p of the welding torch to the curved portion 21k of the welding torch body 21. Thus, the force of the operator acts on the connection plug 21c from the teaching handle 40 via the bracket body 31. Therefore, even if the teaching handle 40 is installed near the curved portion 21k of the welding torch body 21, manual welding can be performed while suppressing the swing of the welding torch tip 21t, and the welding action can be taught to the robot body 10 with high accuracy.

[0097] As mentioned above, although embodiment of the present invention is described in detail, the present invention is not limited to the above-mentioned embodiment, and various design changes can be made within the scope not departing from the gist of the present invention described in the claims.

Claims

1. A welding robot comprising a multi-jointed robot body and a welding torch mounted on the front end of the robot body, wherein the welding robot is characterized in that: The welding torch includes a welding torch body and a connecting portion connecting the welding torch body to a front end of the robot body. The torch body has a bent portion formed by bending the torch body between the torch base end of the torch body and the torch front end of the torch body. The connecting portion has a holding mechanism for holding the base end of the welding torch via a connection plug so that the front end of the welding torch can swing freely relative to the connecting portion. The welding robot further includes a teaching handle, which, when held by an operator, teaches the movement of the robot body corresponding to the moving position of the front end of the welding torch by means of an operating force applied by the operator to the front end of the robot body. The teaching handle is mounted on the welding torch via a bracket. The bracket has: a bracket body which is detachably fixed to the connection plug and is arranged in parallel with a first portion of the torch body from the torch base end to the bent portion at a distance therefrom; and A handle support portion supports the teaching handle in such a manner that a handle front end of the teaching handle is arranged at a position facing the curved portion.

2. The welding robot according to claim 1, characterized in that: A resin fixing plate is fixed to the connection plug. The bracket body is fixed to the fixing plate so as to surround the connection plug in a state where the bracket body does not come into contact with the connection plug.

3. The welding robot according to claim 2, characterized in that: When the welding torch body and the teaching handle are observed from the side, the teaching handle extends in a direction away from the bending portion to the second portion of the front end of the welding torch, clamping a first welding torch imaginary line along the first portion of the bending portion from the welding torch base end in the welding torch body. The bracket body is fixed to the connection plug in a detachable manner via the fixing plate by a detachable member with a push button. The mounting and dismounting member releases the locking of the fixing plate and the bracket body by pressing the push button. The attachment / detachment tool is attached to the bracket body and the fixing plate such that the pressing direction of the push button is a pressing direction from the bracket body side with respect to the fixing plate.

4. The welding robot according to claim 1, characterized in that: The bracket body has an opening formed therein for exposing a first portion of the torch body from the torch base end to the bent portion when the torch body is viewed from the teaching handle side.

5. The welding robot according to claim 1, characterized in that: The bracket body is made of metal, and the handle support portion is made of resin. The handle support portion includes a pair of clamping members for clamping the teaching handle.

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