JPH0528565U - Robotic gas shield metal arc welding equipment - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a gas shield metal arc welding device by a robot that can handle a wide range of welding conditions, can effectively use a robot, and can effectively use a shield gas and shorten welding work time. .. Constitution: One end is connected to a welding torch 3 provided in the robot 2, and shield gas supply paths 8, 9 and 10 for supplying different kinds of shield gas and these shield gas supply system paths 8, 9, 10 are provided. Switching valves 8a, 9a, 10a for controlling shield gas supply, regulator 8
b, 9b, 10b are provided, and the switching valve 8a, according to an instruction from the controller 11 based on preset welding conditions,
9a, 10a and the regulators 8b, 9b, 10b are controlled, and the welding current is switched by the welding power source switching device 12 so that a wide range of welding conditions can be dealt with, and when the shield gas is switched according to the welding conditions, the shield gas The shielding gas is not required to be released between the switching valve and the welding torch for keeping the mixing ratio of the welding gas constant, and the shielding gas can be effectively utilized, the preflow time can be shortened, and the welding work efficiency can be improved. Can be achieved.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a robot gas shield metal arc welding apparatus.

[0002]

[Prior Art]

 For example, in a vehicle assembly factory, a vehicle body frame F used for a truck or the like shown in a perspective view in FIG._a , F_a And support bracket F in advance_b , F_b Cross member F welded at both ends_c, F_c… Set, side member F _a , F_aAnd support bracket F_b, F_bCross member F via ..._c, F_c... are joined by gas shield metal arc welding with a robot to assemble the main part. Subsequently, small parts such as various brackets b, b ... Are temporarily attached by manual welding, and subsequently assembled by a permanent attaching process by gas shield metal arc welding by a robot.

Next, the body frame assembled by the welding process measures the amount of deformation of each portion due to welding strain in the shape correcting process as disclosed in Japanese Utility Model Laid-Open No. 61-172609, and based on the measured value. The body frame is pressed under the pressure 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 the welding robot, in the manufacture of automobiles, a diversification of demands of purchasers is unavoidable, so that a small number of different types of vehicles are produced. A wide range of welding conditions are required because the material, surface treatment for the purpose of rust prevention, and plate thickness of the material differ depending on each specification.

For this reason, measures have been taken such as welding current control and the robot being provided with a plurality of welding devices for different shield gases. However, the control range of the welding current is narrow, and installing multiple welding devices in the robot complicates the structure and raises the equipment cost, and the welding posture of the robot is limited. There are problems such as not being able to obtain sufficient effective use.

As a countermeasure against this, the present applicant opens and closes a shield gas supply system passage and a shield gas supply system passage for supplying different kinds of shield gas to a welding torch provided in a robot according to Japanese Patent Application No. 3-220858. A gas shield by a robot that can handle a wide range of welding conditions by providing a switching valve for switching and selectively opening and closing these shield gas supply system passages with a switching valve according to instructions from a control device based on preset welding conditions. A metal arc welding device was proposed. According to this welding device, a wide range of welding conditions can be met without causing a rise in equipment costs, and the robot's welding posture is not restricted, so that the robot can be effectively used. However, since the shield gas sent from each shield gas supply system line is supplied to the welding torch via one conduit, when switching the shield gas according to the welding conditions, the mixing ratio of the shield gas It is necessary to lengthen the preflow time immediately before welding to replace the shield gas between the switching valve and the welding torch in order to keep the temperature constant.Since the shield gas is released during that time, effective use of the shield gas cannot be achieved. There are problems such as cost up and increased welding work time due to the need to increase the preflow time.

Therefore, an object of the present invention is to provide a robot gas shield metal arc welding apparatus that can effectively use shield gas and reduce welding work time.

[0008]

[Means for Attempting to Solve the Problems]

 In order to achieve the above object, a gas shield metal arc welding apparatus by a robot according to the present invention comprises a robot, a welding torch provided on the robot, and one end connected to the welding torch. A plurality of shield gas supply system passages, and a plurality of switching valves for opening and closing each of the shield gas supply system passages in response to an instruction from a control device based on preset welding conditions.

[0009]

[Action]

 Each shield gas supply system that supplies different kinds of shield gas to the welding torch provided in the robot is opened / closed by each switching valve according to the instruction from the controller based on the preset welding conditions.

[0010]

【Example】

 An embodiment of the robot gas shield metal arc welding apparatus according to the present invention will be described below with reference to the drawings when it is applied to the assembly of a vehicle body frame used for a truck or the like shown in FIG.

In the welding process for assembling the vehicle body frame F as described above, the side members F are positioned by the positioning devices such as the clamps 1, 1 ... _a, is set supported on F _a and across the bracket F _b, F _b ... pre welding combined cross member F _c, the F _c or the like to a predetermined position.

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

The support bracket F _b welded to the side member F _a is lower as shown in FIG. 3 which is an enlarged perspective view of the portion a of FIG. 2 and FIG. 4 which is a sectional view taken along the line AA of FIG. It has a substantially U-shaped cross section having a joint portion with a cross member F _c that bulges inward, and holds the side member F _a from the inner side F _aa and the outer side F _ab with both upper edge F _ba and F _bb facing each other, and The upper edges F _ba and F _bb are joined by gas shield metal arc welding by the robot 2.

[0014] Welding Welding bond Moreover penetration and low cost of the inner F _aa rhino Domenba F _a to be small vehicle inward side of touching the person from the outside and the upper end F _ba of the support bracket F _b when working stable, with firmly carbonate gas shielded arc welding method that can be welded (CO ₂ gas welding method), also welded joins the upper edge F _bb and side members F _a to be outside of the vehicle body, the time of the CO ₂ gas welding 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, to the pulse MAG welding method in which spray transfer is easier. To prevent spatter from occurring and improve the 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 which 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 explained with reference to the schematic explanatory view shown in FIG.

The robot 2 is arranged in the vicinity of a welding jig, and a welding torch 3 is attached to the wrist of the robot 2 via a wrist flange 2a. The welding torch 3 is formed in a substantially cylindrical shape as a whole, and a welding wire, which is a consumable electrode, is inserted along the axis of the welding torch 3 and the welding wire is extended for a predetermined length from the tip of the welding torch 3. The wire feeding device 4 provided on the base 2b of the robot 2 feeds it through the conduit 5 according to the wear of the ear. The base end of the welding wire is wound around a wire reel (not shown) arranged in the vicinity of the robot 2 and sequentially supplied. Further, the welding wire supplied to the welding torch 3 is connected to the welding power source 7 via the welding cable 6.

The welding torch 3 is connected to one end of each of first, second and third shield gas supply system passages 8, 9 and 10 which are gas hoses or the like in order to bring the gas supply portion as close as possible. The base ends of the shield gas supply system passages 8, 9 and 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 system passages 8, 9, and 10 are provided with switching valves 8a, 9a, 10a, and switching valves 8a, 9a, 10a that are opened and closed by an instruction from a control device 11 based on preset welding conditions. There are provided regulators 8b, 9b, 10b for adjusting the flow rates of the shield gas supply system passages 8, 9, 10 by, for example, switching the gas flow rate for a predetermined time to be larger than that in the steady state when switching.

Based on the preset welding conditions, the control device 11 controls the switching valves 8a, 9a, 10a and the regulators 8b, 9b, 10b arranged in the respective shield gas supply system passages 8, 9, 10. In accordance with the above instruction, for example, a shielding gas having a mixing ratio suitable for the CO ₂ gas welding method and the MAG gas welding method shown in Table 2 is obtained.

[0020]

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

With the gas shield metal arc welding apparatus configured as described above, the side member F shown in FIGS._aAnd cross member F_cSupport bracket F coupled to_b In order to weld and join with, the side member F is welded with a welding jig._aSupport bracket F _b Both upper edges F_ba, F_bbAnd side member F_aInside and outside F_aa, F_abSet the positioning so that you can hold it from both sides.

Next, the switching valves 8a, 9a, 10a and the regulators 8b, 9b, 10b are operated by an instruction from the control device 11 based on the preset welding conditions, and the first shield gas supply system passage 8 is closed. and, and a second shielding gas supply line 9 O ₂ gas from the third shield gas supply line 10 in accordance with the welding torch 3 to the CO ₂ required CO ₂ gas and shielding the gas in the gas welding opens the For example, it is supplied as a shielding gas having a mixing ratio suitable for CO ₂ gas welding 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 the welding condition preset by the instruction from the controller 11.

[0023] Then the inner F _aa 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 of the support bracket F _b The joint with the upper edge F _ba is used as a welding line for stable welding by CO ₂ gas welding.

Next, the switching valves 8a, 9a, 10a and the regulators 8b, 9b, 10b are adjusted in accordance with instructions from the control device 11 according to preset welding conditions, and the shield gas supply system passages 8, 9, 10 are adjusted. The flow rate of each gas is controlled, and Ar, CO _{2 as} a shield gas for MAG welding and O ₂ gas as necessary are supplied to the welding torch 2 as a shield gas having a mixing ratio suitable for MAG welding shown in Table 2. In addition, the welding current switching device 12 is controlled by an instruction from the control device 11 so that a welding current suitable for MAG welding can be supplied from the welding power source 7 to the welding wire, and then the control device 11 is operated according to the set welding conditions. and controls the robot 2 by, by the MAG welding along the junction of 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 away Tsu is welded with a small spray transfer mode of data generation.

In this way, when welding the side member F _a and the support bracket F _b , the inside F _aa of the side member F _a and the upper edge F _ba of the support bracket F _b , which are rarely seen, are CO ₂ inexpensively by gas welding, moreover arcing MAG welding high welding bonds penetration of stability, also an outer F _ab of more side members F _a be visible to the upper edge F _bb of the support bracket F _b Is spray-transferred to reduce the amount of spatter, and a high-quality body frame F that is desirable in appearance can be obtained.

[0026] In the above description there has been described a case where the workpiece welded together by switching the side members F _a and the support bracket F _b of the vehicle body frame F to C O ₂ gas welding and MAG welding, the thin plate during the CO ₂ gas welding When arc welding is performed, the switching valves 8a, 9a, 10a and the regulators 8b, 9b, 10b are appropriately adjusted according to an instruction from the control device to switch the gas supply to the MAG welding, and further, the welding power supply switching device 12 if necessary. The welding current can be controlled by means of the spray transfer mode to widen the allowable range of welding and easily weld according to the welding conditions.

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

[0028] are those more galvanized steel sheet according to the welding apparatus of the present invention, an aluminum alloy, the applicability of a titanium alloy or a copper alloy such as CO ₂ According to gas welding blowholes or the like occurs easily CO ₂ gas welding poor However, the switching valves 8a, 9a, 10a, the regulators 8b, 9b, 10b, and the welding power source switching device 12 are used to switch to spray transfer and MAG welding with a wide allowable range, so that suitable welding conditions can be easily obtained.

Further, in the case of thinner steel plates, plate joints of aluminum alloys and stainless steels, etc., a pulse that further enables spray transfer by controlling the welding current by the welding power source switching device 12 from the MAG welding mode. It is possible to easily deal with this by switching to MAG welding.

The switching to CO ₂ gas welding, MAG welding, and pulse MAG welding and the adjustment of the shield gas mixture ratio should be preset in the controller 11 at the same time as teaching to the robot in accordance with each welding condition. It can be used effectively in other manufacturing fields in which arc welding is performed, without being limited to automobile assembly.

[0031]

[Effect of the device]

 According to the gas shield metal arc welding apparatus for robots of the present invention described above, one end of a plurality of shield gas supply system passages for supplying different kinds of shield gas is connected near the welding torch provided in the robot. , These shield gas supply system paths are adjusted according to the instruction from the control device that matches the preset welding conditions, the switching valve and regulator are adjusted, and the welding current is switched by the welding power source switching device. Welding suitable for welding conditions can be performed. Furthermore, when switching according to the gas shield welding conditions, the gas supply part is installed as close as possible to the welding torch, so the shield between the switching valve and the welding torch is kept to keep the gas shield mixture ratio constant. There is no need to replace the gas, so the shield gas is not released during that time, the shield gas can be effectively used, and the preflow time can be shortened, which shortens the welding time and reduces the welding work efficiency and cost. Is obtained.

[Brief description of drawings]

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

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

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

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

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

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

[Explanation of symbols]

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

Claims (3)

[Scope of utility model registration request] 1. A robot, a welding torch provided on the robot, a plurality of shield gas supply system paths each having one end connected to the welding torch and supplying different kinds of shield gas to the welding torch, and preset. A gas shield metal arc welding device by a robot, comprising: a plurality of switching valves that open and close each of the shield gas supply system paths according to an instruction from a control device based on the welded conditions. 2. The apparatus according to claim 1, wherein each shield gas supply system path has a regulator for adjusting the flow rate of the shield gas according to an instruction from a control device based on preset welding conditions. 3. The apparatus according to claim 1, further comprising a welding power source switching device for switching and controlling a welding current according to an instruction from a control device based on preset welding conditions.