JPH05154658A - Laser sensor for welding machine - Google Patents

Abstract

PURPOSE:To miniaturize a welding machine having a laser sensor light in weight and to elevate the followup ability of a welding line. CONSTITUTION:A sensor box 6 supported freely rotatively through a bearing 5 and rotated by a hollow electric motor 4 is mounted on a welding torch 1 mounted on the tip of a robot hand. A CCD color camera 11 observing a welding member 8 through two flat mirrors 13 and a filter 12 is mounted on the sensor box 6. Since an amplifier 7 of amount of air and a generator 14 of cold air are mounted on the sensor box 6, the sensor box 6 is made difficult to be influenced by arc light, spatter, etc., generated in a welding time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser sensor for a welding machine capable of automatically copying a welding line, and is applicable to MAG welding.

[0002]

2. Description of the Related Art Conventionally, a semiconductor laser slit light type sensor has been used as a sensor in various industrial fields. In recent welding work, in order to improve work efficiency, such a semiconductor laser slit optical sensor is mounted on the robot hand, the welding line is detected by this sensor, and the robot hand follows the welding line. Welding machines that perform welding work while operating

The semiconductor laser slit light type sensor is
Since there is a risk that the performance will be deteriorated by arc light, spatter, heat, fumes, etc. generated during welding, it was installed away from the welding torch.

[0004]

As described above, the conventional semiconductor laser slit light type sensor is affected by arc light, spatter, heat and fumes generated during welding. Therefore, it is necessary to keep the distance from the welding torch. I had to do it. Therefore, the structure becomes large and heavy, and it is difficult to mount the robot hand near the welding torch located at the tip portion.

On the other hand, in the conventional structure, the positional relationship between the sensor and the welding torch is fixed, and since it is necessary to increase the distance between them as described above, the welding line is bent. , It is impossible to follow along the welding line. Furthermore, since the distance between the sensor and the welding torch needs to be increased, the size of the device becomes large and it cannot be applied to narrow places.

Due to various restrictions as described above, the conventional laser sensor of the welding machine cannot obtain a sufficient sensing function.

[0007]

A laser sensor for a welding machine according to the present invention includes a welding torch supported by a robot so as to automatically follow a bending welding line and having a function of sucking and discharging welding fumes. A sensor box, which is a frame rotatably supported by a welding torch and has a built-in device having a cooling function, and is located between the sensor box and the welding torch, and the sensor box is centered on the welding torch. A motor driven to rotate as described above, a laser diode which is partially incorporated in the sensor box and each component is located separately, and a CCD camera which is incorporated in the sensor box and has a flat mirror and an interference filter facing each other. It is characterized by having.

[0008]

The welding line is detected by the laser diode rotated by the motor and the CCD camera, and the robot moves the welding torch along the welding line. Further, welding work is performed by generating an arc from the welding torch.

That is, the sensor box is always positioned and controlled in the forward traveling direction of the welding torch by the rotation of the motor, and the light from the laser diode, which is reflected from the welding line, is passed through the plane mirror and the interference filter to C
The CD camera receives the light and causes the welding torch to follow.
Further, the welding torch sucks and discharges the welding fumes generated during the welding operation, and the device having the cooling function cools the sensor box.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A laser sensor for a welding machine according to an embodiment of the present invention is shown in FIGS. 1 and 2, and this embodiment will be described with reference to these drawings.

Here, FIG. 1 is a sectional view showing the structure of the laser sensor of the welding machine of this embodiment, and FIG. 2 shows the welding condition using the welding machine with laser sensor of this embodiment.

As shown in FIG. 1, a welding torch 1 is passed through a hollow sleeve 2 in a penetrating state and fixed by a holder 3. The sleeve 2 holds a rotating armature that serves as an inner ring of the hollow electric motor 4, and is held by bearings 5 at the upper and lower positions of the rotating armature. The stator, which is the outer ring of the hollow electric motor 4, the brush ring, and the outer ring side of the bearing 5 are incorporated and fixed in the sensor box 6.

On the other hand, at the tip of the welding torch 1, there is provided a cylindrical air amount amplifier 7 which forms an end surface of the sleeve 2 and has an inner surface on the end surface side having a taper portion. Further, a light emitting portion of a laser diode 9 which emits light in parallel with the welding torch 1 and has a certain distance from the welding member 8 and which has a cylindrical lens (not shown) in the front portion is arranged in the sensor box 6. Since the drive unit and the power supply unit, which are not shown constituent members of the laser diode 9, are connected to the light emitting unit by the extension cable, they are separately mounted on the non-movable portion of the articulated robot 10. That is, in order to reduce the size of the sensor box 6, the light emitting part and the driving part / power supply part of the laser diode 9 are separated.

On the other hand, the CCD color camera 11 arranged in the sensor box 6 in a nearly vertical posture is provided with the welding torch 1.
A filter 12 and two opposing flat mirrors 13 are combined with the front of the CCD color camera 11 so as to monitor the groove of the welding member 8 directly below the laser diode 9. Therefore, the CCD color camera 11
Will be held at an angle that gives the optimum image field of view. Further, the image obtained by the CCD color camera 11 is inverted twice by being reflected by the two plane mirrors 13, and it is possible to obtain an appropriate image without inverting the vertical and horizontal directions. As a result, the CCD color camera 11
Can indirectly obtain an image from the reflection of two plane mirrors facing each other.
The optimal placement of the The low temperature air generator 14 is attached to the upper surface of the sensor box 6 with the low temperature cold air outlet 14a located inside and the hot air outlet 14b located outside.

A case will be described below in which the welding machine of the present embodiment having the above-described structure is used to automatically follow the welding line 20 bent by MAG welding. First, the laser light emitted from the laser diode 9 becomes a slit shape by passing through the cylindrical lens, and is applied to the groove portion of the welding member 8. At this time, the slit light causes welding line 2
The direction of the laser diode 9 is preliminarily positioned so that the laser diode 9 strikes perpendicularly to 0. Therefore, in the CCD color camera 11, only the wire, arc light, molten pool and groove wall surface state of the welded portion, and further the contour in the groove shape before welding in front of the welded portion are obtained as images through the filter 12.

The optimum target position of the welding torch 1 is obtained by image processing of these, and the amount of deviation from the current position is detected to control the position of the welding torch 1, that is, the position of the arm of the articulated robot 10. You can copy automatically.

Further, it is possible to optimally control welding conditions such as welding speed, current and voltage from this image. Then, the direct drive type hollow electric motor 4 is welded to the torch 1
Since the sensor box 6 is mounted around the welding torch 1 to rotate around the welding torch 1, the hollow electric motor 4 is drive-controlled to rotate the sensor box 6 around the welding torch 1 to cause the laser diode 9 to move. It is possible to control the welding torch 1 so that it is always located in front of the welding torch 1, and the welding line following control can be performed by causing the arm of the articulated robot 10 to follow the bent welding line 20.

On the other hand, the sensor box 6 is heated by the heat generated during welding. By supplying compressed air to the low temperature air generator 14, low temperature cold air can be obtained. Also,
By supplying cooling water from the joint 15 and circulating the water passage 21 provided in the main body of the sensor box 6, the inside of the sensor box 6 can be cooled and the influence of heat can be removed to protect the device. The low temperature air generator 14 applies the principle of the vortex tube, and cools the inside of the sensor box 6 in which the laser diode 9 and the CCD color camera 11 are housed so that low temperature cold air is obtained from compressed air. However, it was decided to prevent overheating.

Further, by supplying compressed air to the joint 16 for the fumes, a negative pressure flow is generated from the opening 7a of the air amount amplifier 7 to suck the fumes in the peripheral portion, and the sleeve 2 and the welding torch 1 Sleeve 2 through the gap
It can be discharged from any position such as the upper surface of the.

A red semiconductor laser diode is adopted as a measure against arc light from the viewpoints of the problem of the sensitivity range of the CCD color camera 11, ease of position and focus adjustment, maintainability, and miniaturization. Further, in order to protect the laser diode 9 and the CCD color camera 11 against spatter, the optimum arrangement is made so as to be outside the scattering range of spatter.

[0021]

The laser sensor of the welding machine according to the present invention is
As a result of the structure that is less susceptible to arc light, spatter, heat, and fumes generated during welding, the sensor box can be made smaller and lighter, and can be easily mounted on the arm tip of a general-purpose articulated robot. Became possible.

Therefore, by operating the robot,
It is possible to follow a curved welding line and perform automatic copying, and since it is downsized, it can be applied to narrow places. From the above, it is possible to improve the sensing accuracy.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of a laser sensor of a welding machine according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a welding state using a laser sensor of a welding machine according to an embodiment of the present invention.

[Explanation of symbols]

 1 Welding torch 2 Sleeve 3 Holder 4 Hollow electric motor 6 Sensor box 7 Air amount amplifier 8 Welding member 9 Laser diode 10 Articulated robot 11 CCD color camera 12 Filter 13 Plane mirror 14 Low temperature air generator 15, 16 Joint

Claims (1)

[Claims] 1. A welding torch supported by a robot so as to automatically follow a bending welding line and having a function of sucking and discharging welding fumes, and a frame body rotatably supported by the welding torch. A sensor box having a built-in device having a cooling function, a motor located between the sensor box and the welding torch and rotating the sensor box about the welding torch, and a part of the sensor box. A laser sensor for a welding machine, comprising: a laser diode incorporated and having respective constituent members separately positioned; and a CCD camera incorporated in the sensor box and having a flat mirror and an interference filter facing each other.