JPH0641734Y2 - Weld line trajectory deviation detection device - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a seam, for example, while guiding the welding points of the peripheral side flanges of the main body side and the lid side of a gasoline tank, a radiator, etc. to the welding position by a copying device. Involved in a seam welder with a copying device that is welded, so that the welding line forms an annular weld, is attached to this seam welding machine with a copying device, and the welding line at the portion where the start end and the end end wrap The present invention relates to a device for detecting a track deviation.

[Prior Art] A seam welder presses and holds a welded portion of a work between a pair of roller electrodes, and sequentially applies a voltage between these electrodes while rotating the electrodes to sequentially weld the welded portions. Seam welding is performed. Among these seam welders, a seam welder in which the gasoline tank and the like are formed into a tight container by seam welding the peripheral flanges of the main body side and the lid side of the gasoline tank and the radiator to form an annular weld line , For example, JP-A-58-224083 and JP-B-62-45
As disclosed in Japanese Patent No. 826, a copying device is provided to guide the welding points of the welded portion to the welding position in sequence while rotating the work.

Such a copying device has been devised in order to eliminate the deviation of the trajectory of the welding line as much as possible at the start of welding and when the welding start point makes one round, but nevertheless,
The welding line of the work guided by such a copying device,
The above-mentioned trajectory deviation may occur due to the distortion of the locator itself supporting the work and the deviation of the work fixing position with respect to the locator. If such an orbital deviation becomes larger than the width of the welding line to some extent or more, the sealing property at the welded portion will be impaired and water leakage will occur.

Therefore, conventionally, such a track deviation has been found by visually determining whether or not it is possible or by performing a water leak test.

[Problems to be solved by the invention] However, recently, it has been strongly demanded that the seam welding as described above be performed in an unmanned automatic welding line. Under the circumstances, there is a problem that unmanned operation cannot be carried out if the determination as to whether or not the track deviation is visually made as described above.

Also, if the above-mentioned track deviation can be found only during the water leak test, a large number of products with the track deviation of the welding line may be produced due to the same cause. In such a case, defective products may occur. There was a problem that the rate increased and the production efficiency decreased.

The present invention has been made in view of the above circumstances, and unmanned seam welding in which the welded portion of the workpiece is sequentially guided to the welding position by the above-described copying device to form a welded portion having an annular welding line. Welding line trajectory deviation detection device that can accurately detect the deviation of the welding line trajectory during seam welding and suppress the occurrence of defective products as much as possible while enabling it to be carried out in an automated welding line. Is intended to provide.

[Means for Solving the Problems] In order to achieve the above object, the welding line trajectory deviation detecting device according to the present invention is attached to a seam welding machine with a copying device, and a welded portion passing through a welding position is provided. The distance to the work at the start of welding on a predetermined measurement line that intersects the traveling direction of the workpiece and the work on the measurement line when the welding start point of the welded part makes one round and returns to the welding position. A displacement sensor that detects the distance and whether or not the difference between the distances to the two workpieces detected by the displacement sensor is greater than or equal to a predetermined value set to a value smaller than the width of the welding line, and The gist of the present invention is to include a determination unit that generates an abnormal signal only when the difference in distance is larger than a predetermined value in the determination result.

[Operation] According to the welding line trajectory deviation detecting device of the present invention having the above-described configuration, the trajectory of the welding line at the time of starting welding by the copying device and when the welding starting point makes one round and returns to the welding position again. Not only the deviation is suppressed as small as possible, but also the deviation of the welding line in the width direction when the welding start point makes a round and returns to the welding position again, that is, the deviation of the welding line trajectory is automatically detected. , It is judged whether or not the track deviation is larger than a predetermined value which is set to a value smaller than the width of the welding line, which is an allowable range in which water leakage does not occur due to deterioration of sealing property in the welded part. The abnormal signal is generated only when it is larger than the predetermined value, that is, when the track deviation is out of the allowable range. Therefore, it is possible to suppress the occurrence rate of defective products to the minimum by automatically or artificially stopping the welding work in response to the generation of the abnormal signal.

[Embodiment] The present invention will be described below based on an illustrated embodiment.

FIG. 1 is a schematic side view of a seam welding machine with a copying apparatus provided with a welding line trajectory deviation detecting device according to the present invention, in which 1 is a lower roller electrode and 2 is an upper roller electrode. The upper roller electrode 2 is provided so as to be movable in the vertical direction by a vertical movement mechanism (not shown), so that between the lower roller electrode 1 and the lower roller electrode 1, a pair of upper and lower works W ₁ ,
The peripheral flange w _1, w ₂ of W ₂ has to be pressurized圧挾lifting. The works W ₁ and W ₂ are provided on a pedestal 4 which is rotated by a drive mechanism (not shown), and a clamp member 6 that holds the works W ₁ and W ₂ between them. Are supported so as to rotate integrally with the pedestal 4. Then, the works W ₁ , W
₂ is swiveled so as to be sequentially guided along the annular trajectory of the peripheral flanges w ₁ and w ₂ . That is, the drive mechanism (not shown), the pedestal 4, the locator 5, ..., The clamp member 6 ... constitute a copying apparatus 3 attached to the seam welding machine. Then, the peripheral flanges w ₁ and w ₂ form an annular weld portion in which the welding line L indicating the welding trajectory of the seam welding projects the peripheral flanges w ₁ and w ₂ as shown in FIG. 2, for example. Are tightly coupled to each other.

Now, the welding line L is formed by the lower roller electrode 1 and the upper roller electrode 2 at the welding start point L ₀ near the center of the straight line portion L _s.
Is formed as. Therefore, at the position where the lower and upper roller electrodes 1 and 2 are held by the welded portion, that is, at the welding position P, the traveling directions of the peripheral flanges w ₁ and w ₂ at the start of welding are parallel to the straight line portion L _s , and here In FIG. 2, it is set in the right direction (arrow X direction in the figure).

As shown in FIG. 5, the seam welding machine configured as described above is provided with a welding line trajectory deviation detection device 7 including a displacement sensor 8 and a determination unit 9.

The displacement sensor 8 is a peripheral flange at the start of welding.
In order to measure the distance to the work W ₁ on the lower side on the measurement line m that is substantially orthogonal to the traveling direction of w ₁ and w ₂ , the peripheral direction flanges w ₁ and w _{2 in} the traveling direction X side when viewed from the welding position P Further, it is arranged at a predetermined position facing the straight line portion L _s at the start of welding.
As shown in FIG. 5, the displacement sensor 8 focuses the light emitted from the infrared light emitting diode 8a by the light projecting lens 8b and irradiates the detected object, that is, the work W ₁ with the work.
The light that is diffusely reflected on the W ₁ surface is focused by the light-receiving lens 8c to form a spot on the semiconductor position detection element (PSD) 8d. This semiconductor position detection element 8d uses the image formation position of the spot as an electric signal. By utilizing the fact that it can be captured, it is possible to detect the distance from the position of the infrared light emitting diode 8a or the light projecting lens 8b to the work W ₁ . In the figure, 8e is a calculation unit for calculating the distance to the detected object according to the amount of light projected by the infrared light emitting diode 8a. Further, as shown in Figure 3, in this embodiment the drilled hole 5a for exposure work W ₁ to the locator 87, the workpiece W ₁ the light emitted by the infrared light emitting diodes 8a through the through hole 5a I am trying to irradiate. The displacement sensor 8 is attached to a fixing member 11 which is integrated with a welding machine body (not shown) via a mounting member 10 extending downward.

When the displacement sensor 8 as described above detects that the pedestal 4 of the copying apparatus 3 is at the position at the start of welding by a detection means such as an optical sensor or a limit switch, it causes the infrared light emitting diode 8a to emit light. It is controlled so as to detect the position of the work W ₁ , and therefore, for one set of work, twice at the start of welding and when the welding start points of the peripheral flanges w ₁ and w ₂ return to the welding position. Detect the position of work W ₁ . The distance from the displacement sensor 8 to the work W ₁ detected by the displacement sensor 8 is input to the determination unit 9.

The determination unit 9 first stores a distance y ₁ to the work W ₁ at the start of welding, which is first input in a set of works, and this distance y ₁ and the welding start point of the welding line L that is input next. The distance y ₂ to the work W ₁ when L ₀ returns to the welding position P is compared. By the way, as described above, since the light emitted by the infrared light emitting diode 8a is along the measurement line m orthogonal to the welding line L, the difference between the distance y ₁ and the distance y ₂ is that of the welding line L. This corresponds to the deviation in the width direction, that is, the deviation of the trajectory of the welding line L. Therefore, the determination unit 9 determines whether or not the difference between the distance y ₁ and the distance y ₂ is, for example, greater than 10% of the width of the welding line L, and if greater than 10%, an abnormal signal is generated. .

By doing so, the welding line trajectory deviation detection device 7 of the above embodiment automatically detects the trajectory deviation between the start end portion and the end portion of the welding line L, and if it is, for example, 10% or more, it is abnormal. A signal can be generated. Therefore, it is possible to drive an alarm buzzer or an alarm lamp by this abnormal signal, or to stop the welding operation, and therefore, it is possible to adapt to an unmanned automatic welding line, and such an automatic welding line. Also in this case, the occurrence of defective products can be suppressed to a minimum.

Needless to say, the present invention is not limited to the above-mentioned embodiment, and for example, the position of the displacement sensor may be any position as long as it can detect the deviation of the work in the width direction of the welding line at the welding position. Further, the condition for the determination unit to output an abnormal signal may be a set value or more at which it is determined that a defective product will occur if the difference in the distance to the detected work is smaller than or larger than the width of the welding line.

[Effects of the Invention] As is apparent from the above description, according to the present invention, it is possible to suppress the orbital deviation of the welding line when the welding start point makes one round and returns to the welding position by the copying apparatus. Of course, even with the use of such a copying apparatus, it is not possible to completely avoid the occurrence of orbital deviation due to, for example, the distortion of the locator of the copying apparatus or the deviation of the fixed position of the workpiece with respect to the locator. in view of,
When the welding start point makes one round and returns to the welding position again, the deviation of the welding line in the width direction, that is, the deviation of the orbit of the welding line is automatically detected, and the deviation of the orbit determines the sealability of the welded part. It is judged whether or not it is larger than a predetermined value that is set to a value smaller than the width of the welding line, which is an allowable range that does not cause water leakage due to decrease, and only when it is larger than the predetermined value, that is, track deviation. The abnormal signal can be generated only when is outside the allowable range. Therefore, it becomes possible to stop the welding work automatically or artificially with the occurrence of the abnormal signal, and it is possible to adapt to an unmanned automatic welding line, and to suppress the occurrence rate of defective products to a minimum. Therefore, there is an effect that it can contribute to the improvement of production efficiency.

[Brief description of drawings]

FIG. 1 is a schematic side view of a seam welder with a welding line trajectory deviation detection device, FIG. 2 is a schematic plan view showing a welding line, FIG. 3 is an enlarged schematic side view of essential parts, and FIG. 4 is a plan view of the same. FIG. 5 is a configuration diagram of a welding line trajectory deviation detecting device. 1 ...... lower roller electrodes, 2 ...... upper roller electrode 3 ...... copying apparatus 7 ...... weld line track shift detecting device 8 ...... displacement sensor 9 ...... determination unit W _1, W ₂ ...... work w _1, w ₂ …… Peripheral flange (welded part) L …… Weld line, m …… Measurement line

Claims (1)

[Scope of utility model registration request] 1. A part of an annular welded portion of a work is pressed and sandwiched between a pair of roller electrodes, and a voltage is applied between these electrodes while the electrodes are rotated, so that the copying device moves to a welding position. Weld the welded parts to be guided in sequence,
A welding line showing the welding track is attached to a seam welder with a copying device that forms an annular weld, and a predetermined crossing direction with respect to the traveling direction of the welded portion passing through the welding position is provided. The distance to the workpiece at the start of welding on the measurement line,
A displacement sensor for detecting the distance to the work on the measurement line when the welding start point of the welded part makes one round and returns to the welding position, and the distance between the two works detected by the displacement sensor. A determination unit that determines whether or not the difference is greater than a predetermined value set to a value smaller than the width of the welding line, and that generates an abnormal signal only when the difference in distance is greater than a predetermined value in the determination result. A welding line trajectory deviation detection device comprising: