JP2672879B2 - Welding torch - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a welding torch that detects an external force applied to a welding torch of an industrial welding robot and an automatic welding device to prevent damage from occurring.

[Conventional technology]

Today, the gas shield welding method using consumable electrodes is widely applied to industrial arc welding robots. In order to improve work efficiency, it is necessary to speed up the interpolated position movement speed of each axis of the arc welding robot. Welded structure geometries are becoming more complex. Under this circumstance, the welding torch provided at the tip of the arc welding robot comes into contact with the welded structure at the time of operation, and the welding torch is damaged. The arc welding robot is often applied mainly to the production line, and the stoppage of the production line due to a failure causes enormous damage and has become a serious problem, and is being highlighted.

As means for solving such a problem, a method of buffering a shock of contact by a spring structure or the like even when the welding torch comes into contact with a welded structure and the welding as disclosed in JP-A-58-171279 Arc welding robot as a shock sensor by converting the bending change and the plunge change of the welding torch caused by the contact of the welding torch with the welding structure into the vertical movement by the mechanical transmission structure and further converting the vertical movement electrically. A method has been proposed in which a signal is input to the control unit of the above and the operation of the arc welding robot is emergency stopped to prevent damage.

[Problems to be solved by the invention]

However, in the case of the above-mentioned contact buffering, in the present situation where the moving speed of the interpolated position of each axis of the arc welding robot is becoming higher and higher, it is a situation that cannot be prevented by buffering only by the spring structure. The invention disclosed in JP-A-58-171279 is mechanically transmitted by bending and plunging change of the welding torch due to contact with the welding torch, further vertical change transmission, and finally failure due to electrical change and complicated transmission structure. Occurs frequently and there is a problem of maintenance. In addition, since the shape is also large structurally and the weight is heavy, the size which is not suitable for application due to the problem of inertia at the time of starting and stopping the operation of the arm of the arc welding robot for high speed operation is complicated and narrow. There was a problem that the welding torch did not enter the welded part of the welded structure that was open.

The present invention has been made in view of the above point, and can follow the increase in the moving speed of the interpolated position of each axis of the arc welding robot, and still accurately detects the contact of the welding torch with the welding structure. It is possible to provide a compact, lightweight welding torch.

[Means for solving the problem]

The gist of the present invention is, in a welding torch in which a consumable electrode wire passes through the center of the shaft, in a bracket provided on the welding torch, a non-conductive flanged wire guide from a plurality of ring-shaped conductive materials. A structure in which the constituted carbon plate and a good conductive material sandwiching the carbon plate are guided and held by the non-conductive wire guide with a flange, and the good conductive material sandwiching the carbon plate is pressed by the spring spring from the upper part of the non-conductive flange. And a shock sensor for detecting a change in electric resistance value between the lead wire and a bracket provided on the upper part of the welding torch, a carbon plate, and a lead wire made of a material having good conductivity that sandwiches the carbon plate. For torch.

[Action]

 The present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram of an application example in which the welding torch 8 with the shock sensor 15 of FIG. 2 is installed in the arc welding robot 11. When performing the welding 12 of the horizontal corner of the welded structure 10 by the arc welding robot 11, the consumable electrode wire 13 is guided by the wire feeder 16 through the conduit cable 6 to the welding torch 8 provided with the shock sensor 15.
12 is performed. When the welding 12 is completed, each axis C of the arc welding robot 11 operates to shock when the welding torch 8 comes into contact with the welding structure 10 when welding another welding portion. The electric signal from the sensor 15 is sent to the control unit 9 of the arc welding robot 11 to stop the operation of the arc welding robot 11 in an emergency, so that the welding torch 8 is released.
To protect from damage.

FIG. 2 is a sectional view in which the welding torch 8, the shock sensor 15 and the conduit cable 6 are integrated. The welding torch 8 has a wire guide 3 with a flange from the shock sensor 15 and a gun core 18 for power feeding closely fixed to the central axis, and a power feeding terminal 17 for welding power is provided on the gun core 18 at the tip. The consumable electrode wire 13 is energized by the power supply tip 22. The shielding gas for welding is insulated from the gas inlet 14
It is a structure in which the welded portion is shielded by being ejected from the nozzle 21 from the orifice 20 through the inside of 19. The wire guide with flange 3 and gun core 18 should be fixed tightly by packing and fixing screws.
It is completely fixed by 23 (not shown). Further, the conduit cable 6 is fixed with an adjusting fixing screw 24 provided on the upper portion of the bracket 2 so as to leave a gap Y between the tip of the conduit cable 6 and the upper surface of the flange portion of the flanged wire guide 3. . The gap Y allows movement of the welding torch 8 in the axial direction when the flanged wire guide 3 is inclined θ.

3a and 3b are detailed sectional views of the shock sensor 15 of the present invention shown in FIGS. Figure 3a shows
FIG. 3b is a normal state diagram in which the shock sensor 15 has no external action, and FIG. 3b shows a state diagram in which the shock sensor 15 is applied with an external action X1.

Fig. 3a shows a welding torch 8 connected via a non-conductive wire guide 3 with a flange and acting in the outer circumferential direction X1, X.
2 and a normal state diagram in which the plunging action Z1 and Z2 does not occur, and the lead wire 1 is externally connected from the ring-shaped good conductor 4 in which a plurality of ring-shaped carbon plates 5 are sandwiched on the lower surface of the flanged wire guide 3. On the other hand, the entire structure in which the wire guide 3 with flange is pressed from the upper surface by the spring 7 is wrapped with a bracket 2, and the lead wire 1'is led out from the bracket 2 to between the lead wires 1 and 1 '. The electric resistance value of becomes a low resistance value. The electrical signal corresponding to this resistance value is first
It is input to the control unit 9 of the arc welding robot shown in the figure, and when the resistance value is low, the operation of the arc welding robot is continued.

FIG. 3b is a schematic diagram in which the welding torch 8 comes into contact with the welded structure 10 on the non-conductive flanged wire guide 3 and a force of external action X1 is exerted. When the flanged wire guide 3 is tilted θ by the external action X1, the lower surface of the flanged wire guide 3 becomes rough between the plurality of ring-shaped carbon plates 5 or gaps are formed. The electric resistance value between the lead wires 1 and 1'becomes a high resistance value, and the control unit 9 of the arc welding robot shown in FIG. 1 stops the operation of the arc welding robot 11 in response to the electric signal corresponding to the high resistance value. The welding torch 8 is protected from damage.

The external action is the same as the above-mentioned action function not only from X1 and X2 but from any position on the circumference. When the welding torch 8 is thrust into the welded structure 10, the flanged wire guide 3 is pushed up from below by a vertical external action Z1 to Z2 direction to form a plurality of ring-shaped carbon plates 5. Due to the formation of the gap, the electric resistance value between the lead wires 1 and 1'becomes a high resistance value, and the control unit 9 of the arc welding robot shown in FIG.
The operation of 11 is stopped to protect the welding torch 8 from damage.

Thus, the present invention is provided with a shock sensor for emergency stop of the operation of the arc welding robot without damaging the welding torch when the welding torch contacts the welding structure, The welding work can be immediately restarted only by the operation of correcting the loci of interpolation positions of the axes of the arc welding robot. The present invention can be applied not only to the industrial arc welding robot but also to other automatic welding equipment and the like.

〔Example〕

An embodiment in which the present invention is applied to an articulated arc welding robot will be described below.

The shock sensor 15 has a thickness of the ring-shaped carbon plate 5 of 1 mm.
8 plates, 1 mm thick upper and lower 1 mm thick copper-like good conductor 4
Sheet, ceramic wire guide with flange 3, aluminum bracket 2, wire diameter 4 mmφ, coil average diameter 2
It consists of a spring 7 made of spring steel SUP with a diameter of 3 mm and a load of 5 kgf, and the gap Y holds a tolerance of 2 mm.

The welding method is a consumable electrode type gas shield welding method, and the welded structure is a multi-joint arc for the purpose of horizontal fillet welding for welding the vertical and lower plates of a T-shaped longe made of mild steel with a thickness of 16 mm. In the operation teaching of the welding robot, the welding torch is set to come into contact with the standing plate of the T-longe, and as a result of starting welding, as a result, between the stop of the welding torch and the maximum moving speed and between the maximum moving speed and the stop. Standing plate of the T-longi at 0.5sec each time and maximum moving speed 0.5m / sec during movement
It was found that the arc welding robot stopped operating when the welding torch 8 had a maximum length of 100 mm and a tilt angle of 2 degrees when the welding torch 8 was contacted, and the welding torch 8 was protected without any damage. The relationship between the inclination angle θ and the operation stop of the arc welding robot is adjusted by a set value of an interface (not shown) built in the control unit 9 of the arc welding robot.

FIG. 4 shows a characteristic curve relating to the electric resistance value between the lead wires 1 and 1 ′ derived from the shock sensor 15 and the inclination angle θ of the welding torch 8.

 Welding conditions and other factors are as follows.

Welding wire: 1.2 mmφ solid wire Applicable welding current value: 200 to 230 (A) Applicable welding voltage value: 28 to 30 (V) Welding speed: 25 to 30 (cm / min) Wire protrusion length: 15 to 17 ( mm) Welding torch with shock sensor Weight: 1.5 (kg) Note that the material inside the shock sensor is a ceramic material such as a wire guide with a flange, carbon fiber, etc., and a ring-shaped good conductor made of copper, silver, gold, etc., an aluminum bracket Needless to say, it is possible to apply materials such as brass and copper.

〔The invention's effect〕

As described above, according to the present invention, even in an extremely complicated welded structure, a mistake in teening of the arc welding robot and a sudden contact accident. Further, even when a human body is contacted, the function of the shock sensor and the shock sensor are provided. By reducing the inertia of the welding torch by reducing its weight, it is effective not only for protecting the welding torch but also for the safety of the human body, and the evaluation of automatic welding can be further enhanced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the external appearance of an arc welding robot equipped with a welding torch with a shock sensor according to an embodiment of the present invention, and FIG. 2 is a cross section of a welding torch with a shock sensor according to an embodiment of the present invention. FIGS. 3a and 3b are detailed views showing the inside of the shock sensor shown in FIG. 2, and FIG. 4 is a characteristic curve diagram of the electric resistance value of the shock sensor and the inclination angle of the torch for welding. 1,1 ': Lead wire, 2: Bracket 3: Wire guide with flange 4: Ring-shaped good conductor plate, 5: Ring-shaped carbon plate 6: Conduit cable, 7: Spring 8: Welding torch 9: Arc welding robot Control part of 10: welding structure, 11: arc welding robot 12: welding, 13: consumable electrode wire 14: gas inlet, 15: shock sensor 16: wire feeder, 17: power supply terminal 18: gun core, 19 : Insulated external cylinder 20: Orifice, 21: Nozzle 22: Power supply tip, 23: Fixing screw 24: Fixing screw for adjustment, X1, X2: External circumference action Z1, Z2: External thrust action, Y: Gap

Front Page Continuation (72) Inventor Kazuo Nagatomo 3-5-4 Tsukiji, Chuo-ku, Tokyo Within Nittetsu Welding Industry Co., Ltd. (56) Reference JP-A-58-171279 (JP, A) 5788 (JP, U) Showa 58-32845 (JP, Y2)

Claims (1)

(57) [Claims] 1. A welding torch in which a consumable electrode wire passes through a central portion of a shaft. In a bracket provided on an upper portion of the welding torch, a non-conductive flanged wire guide is composed of a plurality of ring-shaped conductive members. Structure in which the carbon plate and the conductive material sandwiching the carbon plate are guided and held by the wire guide with the non-conductive flange, and the non-conductive flange sandwiching the carbon plate is pressed by the spring spring from above the non-conductive flange. so,
A welding torch comprising a bracket provided on the upper part of the welding torch, a carbon plate, and a lead wire made of a material having good conductivity that sandwiches the carbon plate, and a shock sensor for detecting a change in electric resistance between the lead wires. .