JP2014024112A - Automatic welding method for automotive exhaust system parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic welding method for automotive exhaust system parts that welds one, or two or more cylindrical shells and plural pipes disposed with the cylindrical shells penetrated through them, and that makes it possible to upgrade working efficiency of welding work and shorten a welding processing time.SOLUTION: An automatic welding method includes: a first step of placing one, or two or more cylindrical shells and plural pipes on a positioner which freely rotatively bears the cylindrical shells and pipes; a second step of holding the one, or two or more cylindrical shells and plural pipes, which are placed on the positioner, using a clamping device fixed to the positioner; and a third step of rotating the positioner with an axis, which is substantially parallel to an axial direction of an exhaust system, as a center while holding the cylindrical shells and pipes with the clamping device, and concurrently performing circumferential welding on plural points using plural articulated robots disposed on a ceiling.

Description

The present invention relates to an automatic welding method for automobile exhaust system parts, in which one or two or more cylindrical shells and a plurality of pipes arranged through the cylindrical shell are welded by a welding robot.

  In general, an automobile exhaust system is composed of a cylindrical shell part such as a catalytic device, a main muffler, and a sub muffler, a pipe-like part that connects between them, and a fastening part such as a flange. Be joined. In many cases, the assembly is divided into several subassemblies in order to secure the assemblability, and the subassemblies are joined together by a flange or the like. Moreover, since it is necessary to join the pipe-shaped part on both sides of the cylindrical shell part, it is necessary to weld at least two or more circumferences per sub-assembly.

Conventionally, all-around welding of these multiple locations is performed one by one by cooperating the positioner and welding robot after setting the cylindrical shell and pipe-shaped parts on a gantry or positioner and fixing them with a clamp device. Automobile muffler automatic welding device that has a cylindrical shell with closed end walls and a muffler pipe that is placed through the center of the cylindrical shell, and can be set horizontally or vertically on the gantry column The set base is set in a horizontal state, and the cylindrical shell 1a and the muffler pipe 1b are set, and the set base on which the cylindrical shell and the muffler pipe are set is rotated in a vertical plane. Patent Document 1 discloses a welding method in which a cylindrical shell and a muffler pipe are automatically and sequentially set one by one by a welding robot by setting the vertical state.
JP 2005-288539 A

In conventional welding robots using 6-axis multi-joint robots, if multiple robots are installed close to each other, the arms interfere with each other and cannot operate smoothly at the same time. It is necessary to perform all-around welding sequentially with one unit. For this reason, since it is necessary to repeat welding work for the number of welding locations, there is a limit to shortening the working time.
The automatic welding apparatus is generally installed in a welding booth equipped with a facility for evacuating arc fume generated by welding and a facility for shielding arc light in order to ensure a working environment. Conventionally, since welding robots are respectively arranged on the floor surface, the welding booth is widened, resulting in problems such as a reduction in space efficiency, an increase in equipment costs, and an increase in energy costs required for smoke exhausting equipment.

Therefore, the present invention increases the working efficiency of welding work for joining one or more cylindrical shells and a plurality of pipes together, shortens the welding process time, saves space, and reduces equipment costs. An object of the present invention is to provide an automatic welding method capable of reducing the energy cost.

In order to solve the above problems, an automatic welding method according to claim 1 of the present invention is an automobile that welds one or two or more cylindrical shells and a plurality of pipes arranged through the cylindrical shell. An automatic welding method for exhaust system parts,
A first step of placing the cylindrical shell and the pipe on a jig frame of a positioner that rotatably supports the cylindrical shell and the plurality of pipes;
A second step of gripping the cylindrical shell and the pipe placed on the jig frame with a clamp device fixed to the jig frame;
The cylindrical shell and pipe are rotated around an axis substantially parallel to the exhaust system component axial direction by driving a servo motor of the positioner,
And a third step of performing circumferential welding at a plurality of locations by a plurality of articulated welding robots installed on the ceiling at the same time.

  The automatic welding method according to claim 2 is a multi-joint welding robot having 7 degrees of freedom, in addition to the above steps.

In addition to the above process, the automatic welding method according to claim 3 performs wire welding by the articulated welding robot after the second process or the third process.

According to the invention of claim 1, there is provided an automatic welding method for automobile exhaust system parts for welding one or a plurality of cylindrical shells and a plurality of pipes arranged through the cylindrical shell, In a positioner that rotatably supports a plurality of cylindrical shells and a plurality of pipes, a first step of placing the cylindrical shells and pipes;
A second step of gripping the plurality of cylindrical shells and the plurality of pipes placed on the positioner with a clamp device fixed to the positioner;
Rotating the plurality of cylindrical shells and the plurality of pipes around the exhaust system axial direction by rotating the positioner;
Since the automatic welding method has a third step of performing circumferential welding at a plurality of locations by a plurality of articulated welding robots installed on the ceiling at the same time, the circumferential welding operation for the cylindrical shell and the pipe can be performed at a plurality of locations simultaneously. Thus, the time for the welding process can be greatly shortened, and the productivity can be improved.
Further, by changing the installation location of the welding robot from the floor surface to the ceiling, it is possible to obtain the effects of improving the space efficiency, reducing the equipment cost, and reducing the energy cost required for the smoke exhausting equipment.

  Since the multi-joint welding robot is a 7-degree-of-freedom multi-joint welding robot, it is possible to perform simultaneous work while avoiding arm interference even in the case of close placement, and a welding robot in which a plurality of locations close to the exhaust system are close to each other. Can be welded simultaneously.

For exhaust system parts, in addition to circumferential welding, wire welding is required for welding the hanger bracket and pipe.
In addition to the above step, after the second step or the third step, circumferential welding is performed by supporting a part such as a hanger bracket against a pipe with an articulated robot and performing line welding with the articulated welding robot. After this, line welding can be performed by the same articulated welding robot. Therefore, welding can be performed in the same process, setting time for a jig in another process is unnecessary, the time of the welding process can be greatly shortened, and productivity can be improved.

It is the front view and side view showing the apparatus structure of the automatic welding apparatus which concerns on this invention. It is a system diagram which shows the structure including the control system of the automatic welding apparatus which concerns on this invention. It is the front view and side view which show the state before workpiece | work placement of the automatic welding apparatus which concerns on this invention. It is the front view and side view which show the state at the time of positioner rotation of the automatic welding apparatus which concerns on this invention. It is a block diagram which shows the structure of the prior art which concerns on Unexamined-Japanese-Patent No. 2005-288539.

2 Welding booth 3 Positioner 4 Articulated welding robot 5 Work 5a Cylindrical shell 5b Pipe-shaped part 6 Fume duct 11 Jig frame 12 Clamp 13 Arm 14 Servo motor 15 Bearing 16 Clamp 17 with positioning 17 Support 51 Robot control panel 52 Process control panel 53 Process operation panel 54 Jig signal line relay panel 55 Welding power supply 56 Gas cylinder 57 Wire feeder 58 Wire reel 59 Welding wire 60 Welding torch

(Explanation of overall view)
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing the overall configuration of an automatic welding apparatus according to the present invention. Here, in FIG. 1, a positioner 3 is arranged on the floor surface in the welding booth 2 as a welding place, and a clamp 12 for gripping a workpiece and a clamp 16 with positioning are placed on the jig frame 11 of the positioner 3. Each is provided. The positioning clamp 16 is provided with positioning pins (not shown). The positioning clamps 16 at both ends are fitted with flanges at both ends so that the positioning pins fit into the bolt hole portions of the flanges at both ends of the workpiece. By positioning, positioning with respect to the jig | tool frame 11 is performed. The clamp 12 and the clamp 16 with positioning are configured to grip each part corresponding to the shape of the workpiece. Due to the effect of the positioning mechanism described above, the workpiece 5 is placed in a predetermined position on the jig frame 11 during the process. Has a function to fix accurately and reliably.

Further, the jig frame 11 is supported by the support columns 17 at both ends via the arm 13. The servo motor 14 is provided on one side of the support portion, and the bearing 15 is provided on the other side. The servo motor 14 rotates in response to a signal from the robot control panel 51 to rotate the jig frame 11 and the gripped work. The height of the clamp 16 is adjusted so that the positioner 3 and the workpiece axis are substantially the same, and the shaft deflection of the workpiece due to the rotation is set to a minimum.
A fume duct 4 is installed at the center of the ceiling of the welding booth 2, and the fumes generated by the welding work are sucked and guided to the flue gas treatment facility. Reference numeral 4 is a multi-joint welding robot having a seven-axis configuration, and the robot base is installed not on the floor but on the ceiling, and the upper arm extends downward from the robot base, and is fixedly arranged in a detachable manner. .

(System configuration)
Next, FIG. 2 is a system diagram showing a configuration including a control system of the automatic welding apparatus according to the present invention. Each multi-joint welding robot 4 includes a welding power source 55, a gas cylinder 56, a wire feeder 57 for feeding a welding wire 59, and a wire reel 58.
A control line is connected from the robot control panel to each articulated welding robot and a welding power source, and is controlled to perform welding at an appropriate timing while performing a teaching operation in advance.
A control line is also connected from the robot control panel to the servo motor 14 of the positioner, and the positioner is driven in cooperation with the operation of each articulated welding robot.
Control lines are also connected from the process operation panel 52 to the robot control panel and the jig signal line relay panel, and each clamp is connected to each clamp from the jig signal line relay panel in accordance with the process start / end timing obtained from the robot control panel. A signal is sent to and the operation of gripping and releasing is performed appropriately.

(Welding robot)
Each articulated welding robot is composed of a plurality of actuators and links, and has seven degrees of freedom. That is, each link is connected via a joint that can be rotated or turned, and is relatively driven by an actuator. A total of seven joints that can rotate and joints that can pivot are provided. Each actuator is controlled by a robot control panel 51 incorporating a computer as control means. Each multi-joint welding robot 2 is taught in advance to perform an optimal operation, and performs an operation according to teaching based on an instruction from a computer.

A welding torch 60 for welding an object is provided at an end effector portion of each articulated welding robot. A welding wire 59 is supplied from a wire reel 58 through a wire feeder 57 to the welding torch, and a shielding gas is supplied from a gas cylinder 56. Each multi-joint welding robot reproduces the teaching operation, so that the welding torch 60 is arranged in an appropriate position and direction with respect to the welding site.
At the same time, the welding power source receives a signal from the robot control panel, and performs welding at the optimum timing and welding conditions based on the results of teaching in advance.

(Positioner)
In a predetermined position of the jig frame 11 of the positioner 3 shown in FIG. 1, a clamp having an appropriate shape is detachably disposed at a position where each part can be accurately and reliably gripped in accordance with the shape of the exhaust system part that is a workpiece. The In addition, clamps with positioning 16 are provided at both ends, and the flanges at both ends are accurately positioned by the effect of positioning pins (not shown). Further, clamps with positioning are adopted for other parts that need to be positioned.
A servo motor 14 is disposed at one end in the longitudinal direction of the positioner 3 and receives the control signal from the robot control panel to operate the servo motor in cooperation with the operation of each articulated welding robot to rotate the positioner. .

  Then, the positioner performs a rotation operation while simultaneously welding a plurality of parts that need to be welded between the cylindrical shell 1a and the pipe 1b of the workpiece by a cooperative operation with each multi-joint welding robot 2 installed on the ceiling. Thereby, circumferential welding at a plurality of locations is performed simultaneously. Hereinafter, an example of a welding method of the muffler 1 will be described.

(First and second steps)
FIG. 3 shows a state before placing a workpiece, and FIG. 1 shows a state after placing the workpiece. A plurality of shell-like exhaust parts 5a, pipe-like parts 5b, or sub-assembled pipe parts with a cylindrical shell conveyed from the previous process are placed at predetermined positions of clamps on the jig frame 11 by a robot or an operator (not shown). Place. This is the first step. At this time, positioning clamps 16 are arranged at both ends and necessary portions, and each component is fixed accurately and reliably so that positional displacement does not occur due to rotation of the positioner or the like. This is the second step.
The gripping / releasing operation of these clamps is performed at an appropriate timing based on a signal sent from the process control panel 52 through the jig signal line relay panel 54 in accordance with the process start / end timing obtained from the robot control panel 51. Done.

(Third step)
Then, the servo motor 14 of the positioner 3 is driven to rotate around the axis in the longitudinal direction of the workpiece while the workpiece is securely gripped by the clamp, and at the same time, the plurality of multi-joint welding robots 2 arranged at the welding site are operated to operate the shell. A plurality of welded portions of the gas exhaust part 5a and the pipe 5b are welded simultaneously. This is the third step.
Control lines are connected from the robot control panel to each multi-joint welding robot, welding power source, and positioner, and each multi-joint welding robot and positioner perform coordinated operations according to the contents taught in advance, and the welding power source has an appropriate timing Controlled to weld at conditions.
In addition, the height of the clamp 16 is adjusted so that the axis of the positioner 3 and the workpiece axis are substantially the same, and the shaft deflection of the workpiece due to the rotation is set to a minimum. This makes it possible to take the optimum position and orientation for welding and to perform smooth operation without interference of each robot. Further, it is possible to reliably perform the entire circumference welding up to the back side of the workpiece which is difficult to weld on the jig frame 11 side.

(Welding completed)
When the welding process of the cylindrical shell 5a and the pipe 5b is completed by simultaneously performing the welding operation by the multi-joint welding robot at all the welding locations, the process control panel 52
Then, an unclamp signal is sent to the clamp 12 through the jig signal line relay board 54, and the muffler 1 in which welding is completed is taken out by a robot or operator (not shown) in a state where the workpiece is opened. Thereby, the automatic welding operation of the muffler 1 is completed.

(Wire welding)
Further, if line welding is necessary for fixing the hanger bracket or the like, after circumferential welding of the cylindrical shell 5a and the pipe 5b is performed, wire welding is performed by the same articulated welding robot 4 to complete the welding.

(Summary)
As described above, since the automatic welding apparatus of the above embodiment is an automatic welding method in which a plurality of multi-joint welding robots 4 installed on the ceiling perform circumferential welding at a plurality of locations, the cylindrical shell 5a and the pipe By performing circumferential welding simultaneously at a plurality of places in the welding operation 5b, the time of the welding process can be significantly shortened, and productivity can be improved.

  In addition, since wire welding can be performed in the same process by the same articulated welding robot 4, the time of the welding process can be greatly shortened, and productivity can be improved.

  In addition, since the servo motor for rotating the positioner 3 by the process control panel 52 and the robot control panel and the articulated welding robot 4 operate in cooperation with each other, it is possible to reliably weld a predetermined welding location of the work 5 and to set it on the positioner 5. Since the workpiece 5 is securely held by the positioner 3 and the jig, a stable set state can be obtained, and the occurrence rate of poor welding can be reduced to obtain a high quality exhaust system product.

  It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within a scope that can achieve the object of the present invention are included in the present invention.

Claims (3)

An automatic welding method for automobile exhaust system parts for welding one or two or more cylindrical shells and a plurality of pipes arranged through the cylindrical shell,
A first step of placing the cylindrical shell and the pipe on a jig frame of a positioner that rotatably supports the cylindrical shell and the plurality of pipes;
A second step of gripping the cylindrical shell and the pipe placed on the jig frame with a clamp device fixed to the jig frame;
The cylindrical shell and pipe are rotated around an axis substantially parallel to the exhaust system component axial direction by driving a servo motor of the positioner,
A third step of performing circumferential welding at a plurality of locations by a plurality of articulated welding robots installed on the ceiling at the same time;
A method for automatically welding exhaust system parts for automobiles, comprising: 2. The method for automatically welding exhaust system parts for automobiles according to claim 1, wherein the multi-joint welding robot is a multi-joint welding robot having seven degrees of freedom. 3. The method for automatically welding automobile exhaust system parts according to claim 1, wherein wire welding is performed by the articulated welding robot after the second step or the third step in addition to the step. .