JP2563664Y2 - Gas shielded metal arc welding equipment by robot - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas shielded metal arc welding apparatus using a robot.

[0002]

Assembly of the vehicle body frame F for use in truck or the like shown in the perspective view of FIG. 6 of the Prior Art For example an automobile assembly plant, generally the side member at a predetermined position by a positioning device provided to the welding fixture in the welding step F _a, F _a and advance the support bracket F _b, F _b ... cross member F _c which is welded together at both ends, and set the F _c ..., side members F
_a, F _a and the support bracket F _b, linked by gas shielded metal arc welding cross member F _c, F _c ... a robotic through F _b ... assemble the main unit. Subsequently, small parts such as various brackets b, b... Are temporarily attached by manual welding, and then assembled in a final attaching step by gas shielded metal arc welding by a robot.

[0003] Next, as disclosed in Japanese Utility Model Application Laid-Open No. 61-172609, the body frame assembled by the welding process measures the amount of deformation of each part due to welding strain in the shape correction process, and based on the measured values. The body frame is pressurized based on the pressurizing stroke to correct the shape of the body frame to ensure the dimensional accuracy of the body frame.

In such a conventional welding process, although the welding operation can be automated by a welding robot,
In the manufacture of automobiles, with the diversification of buyer requests,
A wide variety of welding conditions are required because small-scale production of many models is inevitable, and the material, surface treatment for rust prevention, and the thickness of the material are different depending on the specifications.

For this reason, measures have been taken to control welding current and to provide a plurality of welding devices for different shield gases in the robot. However, the controllable range of welding current is narrow, and the provision of a plurality of welding devices in a robot complicates the structure and causes an increase in equipment costs. There are problems such as ineffective utilization.

As a countermeasure against this, the present applicant has filed Japanese Patent Application No. Hei.
No. 0858, a shield gas supply system for supplying different types of shield gas to a welding torch provided on the robot and a switching valve for opening and closing the shield gas supply system are provided, and these shield gas supply systems are preset. We have proposed a gas shielded metal arc welding machine with a robot that can respond to a wide range of welding conditions by selectively opening and closing with a switching valve according to instructions from a control device based on welding conditions. According to this welding apparatus, it is possible to cope with a wide range of welding conditions without causing a rise in equipment costs, and it is possible to effectively utilize the robot without restricting the welding posture of the robot. However, since the shielding gas supplied from each shielding gas supply line is supplied to the welding torch via one conduit, when switching the shielding gas according to the welding conditions, the mixing ratio of the shielding gas is constant. It is necessary to extend the pre-flow time immediately before welding to replace the shielding gas between the switching valve and the welding torch in order to maintain the temperature. And the need to extend the preflow time leads to an increase in welding time.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a gas shielded metal arc welding apparatus by a robot which can effectively utilize a shielding gas and shorten a welding operation time.

[0008]

Gas shielded metal arc welding device according to the robot of the present invention for achieving the above object In order to achieve the above, a robot, a welding torch provided on the robot, each one end connected to the welding torch, A plurality of shielding gas supply paths each supplying a different type of shielding gas to the welding torch, and a plurality of opening and closing the respective shielding gas supply paths by an instruction from a control device based on welding conditions set in advance. It has a switching valve.

[0009]

It opened and closed by each of the switching valve in accordance with each different type of shielding gas feed respectively Kyusuru instruction from the control unit based on pre-set welding condition of each shielding gas supply line to the welding torch provided to the working robot thing
Release of shielding gas when switching shielding gas
Exit is avoided .

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a gas shielded metal arc welding apparatus by a robot according to the present invention will be described with reference to the drawings, taking an example in which the present invention is applied to the assembly of a body frame used for a truck or the like shown in FIG.

The welding process for assembling the body frame F is performed by a positioning device such as clamps 1, 1... _a , F _a and cross members F _c , to which support brackets F _b , F _b .
_{Fc and the} like are set at predetermined positions.

The side members F _a , F _a set at predetermined positions and the support brackets F _b , F _b ... Pre-welded to both ends of the cross members F _c , F _c are desired adjacent to the welding jig. A ladder-shaped main part is assembled by joining by a gas shielded metal arc welding by a welding robot 2 arranged in a number (only one is shown in FIG. 2).

[0013] The support bracket F _b which are welded to the side members F _a is lower as shown in FIG. 4 is a sectional view taken along line A-A of FIG. 3 and FIG. 3 is a a part enlarged perspective view of FIG. 2 a approximately c-shaped cross section having a coupling portion between the bulging cross member F _c to, facing to both upper edge F _ba, and pinching the side members F _a from the inside F _aa and outer F _ab in F _bb, and The upper edges F _ba and F _bb are joined by gas shield metal arc welding by the robot 2.

[0014] Welding side members F welded to the inner F _aa and the upper end F _ba of the support bracket F _b of _a is moreover penetration at low cost as a small vehicle body inner side of touching the person from the outside when the work is stable, strongly carbonate gas shielded arc welding method that can be welded (CO ₂ gas welding method), also welded to the upper edge F _bb and side members F _a to be outside of the vehicle body, the time of CO ₂ gas welding, sputter To reduce the generation of spatter, switch to the MAG welding method in which Ar gas is mixed with CO ₂ gas and spray transfer is performed, and if necessary, switch to the pulse MAG welding method in which spray transfer is easier. Prevent generation and improve appearance quality.

Table 1 shows the spatter generation rate, penetration stability, and cost corresponding characteristics for the CO ₂ gas welding method, the MAG welding method, and the pulse MAG welding method.

[0016]

[Table 1] Next, the welding robot 2 that can be switched to each of the CO ₂ gas welding method, the MAG welding method, and the pulse MAG welding method as described above will be described with reference to the schematic explanatory diagram shown in FIG.

The robot 2 is arranged near a welding jig, and a welding torch 3 is attached to a wrist of the robot 2 via a wrist flange 2a. Welding torch 3
Is formed in a substantially cylindrical shape as a whole, and a welding wire serving as a consumable electrode is inserted along the axis thereof, and the welding wire is extended from the tip of the welding torch 3 by a predetermined length. The robot 2 is configured to be fed via a conduit 5 by a wire supply device 4 provided on a base 2 b of the robot 2. In addition, the base end of the welding wire is wound around a wire reel (not shown) disposed near the robot 2 and supplied sequentially. Further, the welding wire supplied to the welding torch 3 is connected to a welding power source 7 via a welding cable 6.

The welding torch 3 is connected to one end of first, second and third shield gas supply lines 8, 9, and 10 each comprising a gas hose or the like so as to bring the gas supply unit as close as possible. The base ends of the supply lines 8, 9, 10 are connected to supply sources (not shown) of Ar gas, CO ₂ gas, and O ₂ gas, respectively. Further, the first, second, and third shield gas supply lines 8, 9, and 10 are provided with switching valves 8a, 9a, and 10a that are opened and closed according to an instruction from the control device 11 based on preset welding conditions. Regulators 8b, 9b, and 10b are provided for adjusting the flow rate of the shield gas supply lines 8, 9, and 10 by, for example, increasing the gas flow rate for a predetermined time from the steady state when the flow rate is switched.

Each of these shield gas supply lines 8, 9, 1
The switching valves 8a, 9a, and 10a and the regulators 8b, 9b, and 10b disposed at 0 are controlled based on welding conditions set in advance by a command from the control device 11, for example, a CO ₂ gas welding method shown in Table 2, It is configured such that a shielding gas having a mixing ratio suitable for the MAG gas welding method can be obtained.

[0020]

[Table 2] Further, the control device 11 operates the welding power source switching device 12 based on the preset welding conditions, and supplies a welding current suitable for the welding conditions from the welding power source 7 to the welding wire via the welding cable 6 to the welding current. It has a function of switching, and a function of giving an instruction to the robot 2 so as to correspond to various welding locations and welding lines.

[0021] By thus configured gas shielded metal arc welding device, the welding coupling the support bracket F _b coupled to the side members F _a cross member F _c as shown in FIGS. 3 and 4, the welding jigs both upper edge F _ba of the support bracket F _b the side members F _a by the tool, the inner and outer F _aa side members F _a in F _bb, positioned set to sandwiched from both F _ab.

Next, the switching valves 8a, 9a, 10a and 10b are instructed by an instruction from the controller 11 based on welding conditions set in advance.
a and the regulators 8b, 9b, 10b
The first shield gas supply line 8 is closed, and the second shield gas supply line 9 is opened, and CO2 is supplied to the welding torch 3.
If CO ₂ gas and requires a shielding gas of ₂ gas welding supplies third shield gas supply line 10 from the O ₂ gas, for example, as a shielding gas mixture ratio suitable for CO ₂ gas welding as shown in Table 2. Further, the welding power source switching device 12 is controlled so that an appropriate welding current is supplied from the welding power source 7 to the welding wire based on a welding condition set in advance based on an instruction from the control device 11.

[0023] Then the upper end of the inner F _aa and the support bracket F _b of the side member F _a which is located on the vehicle body inner side actuated the robot 2 by an instruction from the control unit 11 based on the preset welding conditions edges F The joint with _ba is used as a welding line and welded in a strong state by CO ₂ gas welding with stable penetration.

Next, the switching valves 8a, 9a, 10a are switched in accordance with an instruction from the control device 11 according to preset welding conditions.
a and the regulators 8b, 9b, 10b are adjusted to control the flow rates of the respective gases in the respective shield gas supply lines 8, 9, 10 so that the welding torch 3 serves as a shielding gas for MAG welding.
r, CO ₂ and, if necessary, O ₂ gas in MAG shown in Table 2.
Supplying as a shielding gas having a mixing ratio suitable for welding, and controlling the welding current switching device 12 so that a welding current suitable for MAG welding can be supplied from the welding power source 7 to the welding wire by an instruction from the control device 11, and controls the robot 2 by the controller 11 according to the following set welding conditions along the joint between the upper edge F _bb outer F _ab and the support bracket F _b of the side member F _a which is located outside of the vehicle body side MAG
Welding is performed in a spray transfer mode with less spatter generated by welding.

[0025] In welded between the way side members F _a support bracket F _b, supporting the inner F _aa fewer side members F _a be visible to the bracket F _b
Low cost, yet high welding bonds penetration of stability, also for large side members F _a be visible to the outside F _ab and the support bracket F _b upper edge by CO ₂ gas welding the upper edge F _ba of the F _bb is spray transfer arc by MAG welding, appearance preferred high-quality vehicle body frame F is obtained achieving reduction in sputtering.

[0026] In the above description the side members F _a of the body frame F supporting bracket F _b and the CO ₂ gas welding and M
Although the description has been given of the case where the workpiece welding connection is performed by switching to the AG welding, when the thin plate is subjected to the arc welding during the CO ₂ gas welding, the switching valves 8a and 9 are switched according to an instruction from the control device.
a, 10a and regulators 8b, 9b, 10b are appropriately adjusted to switch the gas supply to MAG welding, and if necessary, the welding current is controlled by the welding power source switching device 12 to make the spray transition mode to allow the welding tolerable range. It can be easily expanded and welded according to the welding conditions.

Further as shown the only main part in FIG. 5, the welding torch 3 provided on the wrist of the robot 2, the upper edge F _ba inner F _aa and the support bracket F _b of the side member F _a comprising a weld line towards the junction between the outer F _ab and the support bracket F _bb junction and the side frame F _a formed by two welding torches 3a, 3b, inner F of the side member F _a
The coupling between the upper edge F _ba of _aa and the support bracket F _b welded to the CO ₂ gas welding by the welding torch 3a, and the welding torch the upper edge F _bb outer F _ab and the support bracket F _b of the side member F _a 3b, it is also possible to reduce the amount of displacement of the welding posture of the robot 2 by configuring by welding by MAG welding.

Further, according to the welding apparatus of the present invention, a zinc steel sheet,
Aluminum alloys, titanium alloys and copper alloys are those applicability According the blow holes or the like occurs easily CO ₂ gas welding CO ₂ gas welding is poor, switch valve 8a, 9a, 1
Suitable welding conditions can be easily obtained by switching to a spray transition and a MAG welding with a wide allowable range by the 0a, the regulators 8b, 9b, 10b and the welding power source switching device 12.

In the case of a thinner steel plate or a joint of an aluminum alloy or a stainless steel, the welding current is controlled by the welding power source switching device 12 from the MAG welding mode, and the pulse MAG for enabling a further spray transfer. It is possible to easily cope with it by switching to welding.

The switching to the CO ₂ gas welding, the MAG welding and the pulse MAG welding, and the adjustment of the mixing ratio of the shielding gas can be performed by setting in advance to the controller 11 at the same time as teaching to the robot in accordance with each welding condition. It can be performed effectively and can be widely used in other manufacturing fields where arc welding is performed, without being limited to automobile assembly.

[0031]

According to the gas shielded metal arc welding apparatus by the robot of the present invention described above, a plurality of shielding gas supply paths for supplying different types of shielding gas to the vicinity of the welding torch provided in the robot are provided. One end is connected, these shield gas supply lines are easily adjusted by adjusting the switching valve and regulator according to the instruction from the control device according to the preset welding conditions, and by switching the welding current by the welding power source switching device. Welding suitable for each welding condition can be performed. Furthermore, when switching the shielding gas in accordance with the welding conditions, the gas supply section is provided as close as possible to the welding torch, so the shielding gas between the switching valve and the welding torch for keeping the mixing ratio of the shielding gas constant. There is no need to change the welding time.Therefore, there is no need to exchange the shielding gas during that time, so that the shielding gas can be used effectively, and the pre-flow time can be shortened. It has effects such as being obtained.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing one embodiment of a gas shielded metal arc welding apparatus by a robot according to the present invention.

FIG. 2 is a schematic explanatory view illustrating the assembly of the body frame by the gas shielded metal arc welding apparatus by the robot according to the present invention.

FIG. 3 is an enlarged perspective view of a part a in FIG. 2;

FIG. 4 is a sectional view taken along line AA in FIG.

FIG. 5 is a schematic explanatory view showing another embodiment of the gas shielded metal arc welding apparatus by the robot according to the present invention.

FIG. 6 is a perspective view of a vehicle body frame.

[Explanation of symbols]

 2 ... Robot 3 ... Welding torch 7 ... Welding power supply 8 ... Shield gas supply line 8a ... Switching valve 8b ... Regulator 9 ... Shield gas supply line 9a ... Switching valve 9b ... Regulator 10 ... Shield gas supply line 10a ... Switching valve 10b ... Regulator 11 ... Control device 12 ... Welding power supply switching device

Claims (3)

(57) [Scope of request for utility model registration] And 1. A robot, a welding torch provided on the robot, each one end connected to the welding torch, and each feeding Kyusuru plurality of shield gas supply line each different type of shielding gas to the welding torch, A gas shielded metal arc welding apparatus using a robot, comprising: a plurality of switching valves for opening and closing the respective shield gas supply paths according to an instruction from a control apparatus based on preset welding conditions. 2. The apparatus according to claim 1, wherein each of the shield gas supply lines has a regulator for adjusting a flow rate of the shield gas according to an instruction from a control device based on a preset welding condition. 3. The apparatus according to claim 1, further comprising a welding power source switching device that switches and controls a welding current in accordance with an instruction from a control device based on welding conditions set in advance.