JPS5944144B2 - Profile welding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention improves work efficiency by providing a scanning sensor at a remote position that does not interfere with welding work, and eliminates the phase shift between the welding torch and scanning sensor to provide accurate and easy welding. The present invention relates to a profile welding device that can perform profile control.

Most conventional welding devices that perform automatic tracing welding are of the type where the sensor follows the groove of the weld line and precedes the welding torch, and this can be done regardless of whether it is a contact or non-contact method. I was worried.

In this type of sensor-advanced type, the phase shift that occurs between the torch and the sensor complicates the control circuit because it requires a memory function, and when the sensors are placed close together, the arc There were practical problems such as damage to the sensor due to the thermal effects of heat.

Furthermore, the sensor-advanced type cannot perform welding processes that repeatedly move forward and backward, and the welding work is restricted to one direction.
In order to solve this problem, a complicated procedure such as reversing the relative position of the welding torch and sensor at the welding end would be required.Also, considering the special case where the target weld line is continuous in an endless manner, Repeated welding in one direction is undesirable because it causes twisting of the electrical wiring and welding wire, and therefore, even if the relative position of the welding torch and sensor is changed, it has to be reversed, making the operation cumbersome. Therefore, the disadvantage of complicating the equipment was unavoidable.

The present invention was achieved as a result of various studies in order to cope with and improve the current situation as described above, and in particular, the present invention is based on a mutually orthogonal penetrating relationship between the long diameter cylindrical surface and the short diameter cylindrical surface. In the case of a specific welding operation in which welding follows a welding line consisting of a three-dimensional curve at the joint of interrelated bodies formed as a result, the position can be detected even when the tracing sensor is placed at a location distant from the welding torch. The present invention is characterized in that it has been possible to provide a novel device that can accurately perform the following steps.

However, the device of the present invention having the above characteristics has an arrangement in which the welding torch and the copying sensor are maintained at a predetermined relative position in the direction of the radius of curvature at each point of the welding line consisting of the three-dimensional curve. This is a summary of what has been accomplished, and the detailed aspects thereof will be made clear by the following description shown together with the accompanying drawings. As shown in Figure 1, the workpiece 1 to be welded by the welding device includes a long-diameter main pipe 2 having a long-diameter cylindrical surface, and a short-diameter branch pipe 3 having a short-diameter cylindrical surface smaller in diameter than the main pipe 2. and are joined in a penetrating relationship in which both pipe axes are orthogonal to each other,
In the illustrated example, the long-diameter main pipe 2 is arranged horizontally and the short-diameter branch pipe 3 is arranged vertically, so the weld line' at the joint part is located at the periphery of a saddle shape where the bird's eye shape is a perfect circle. It is clear that a three-dimensional curve is formed.

The structure of the welding device that performs arc welding on the weld line' is as shown in the basic skeleton form in FIG.
a Z-axis that is erected above and has a degree of freedom in the vertical direction; an X-axis that is pivoted at the upper end of the Z-axis and has a degree of freedom in the horizontal direction (left-right direction with respect to the position of the workpiece 1); a Y-axis that is pivoted on the X-axis and has a degree of freedom in the horizontal direction (in the direction of approaching and separating from the position of the workpiece 1); Vertical reference axis V
It has four rotational axes F that perform a revolution movement maintaining equidistant parallelism around the Z-axis and the reference axis The pipes V are provided so that they both remain parallel, and the rotation axis F can rotate on the outside of the short diameter branch pipe 2. A welding torch 6 is pivotally attached to the tip of the rotating shaft F so as to be swingable in a vertical plane. Z axis is 1
The vertical dimension is adjusted by a driving source, for example, an electric motor 7, and the vertical displacement at this time is controlled by a z potentiometer 8.
The length is measured as electrical displacement.

The horizontal dimension of the X-axis is adjusted by five driving sources, such as an electric motor 9, and the horizontal displacement at this time is measured as an electrical displacement by an X potentiometer 10.

Further, the longitudinal dimension of the Y axis is adjusted by an electric motor 11, and the longitudinal displacement at this time is measured as an electrical displacement by a Y potentiometer 12.

The rotating shaft F is rotated by the electric motor 131tc, and the rotational displacement at this time is determined by the F potentiometer 14.
The length is measured as an electrical displacement corresponding to a clockwise rotation angle with respect to the Y-axis. Note that the rotation axis F is the horizontal arm 15.
The welding torch 6 is integrally connected to the reference axis V through one revolution, and rotates once on its axis for every revolution, and is therefore attached to the end of the rotation axis F. X-Y- attached to the rotation axis F with the neutral line aligned with
The F copying sensor 17 can always be directed toward the workpiece 1 side.

Next, the welding torch 6 is swingably attached to the end of the rotating shaft F so that the tip can always be oriented on the extension of the reference axis V.

On the other hand, the X-Y-F scanning sensor 17 has a structure having two tactile elements at the tip, and the welding torch 6 is welded in a neutral state where both tactile elements are in contact with the pipe wall of the short diameter branch pipe 3. It is possible to direct the target to the line' at a predetermined aiming angle, and when the neutral state is deviated from, the correction signal and rotation signal analyzed into both the X-axis component and the Y-axis component are controlled. The electric motors 9, 11, and 131fC are configured to be able to provide outputs to each of the electric motors 9, 11, and 131fC by sending them to the system.

Reference numeral 5 designates a Z-axis scanning sensor which is a feature of the present invention, and the scanning sensor 5 is provided at the lower end of the rotating shaft F on which the welding torch 6 is pivoted to detect the Z-axis component. The electric motor 7f1C is configured to provide an output of the electric motor 7f1C by sending it to the control system.

The welding device configured as described above can determine the height of the welding torch 6 based on the electrical displacement of the Z potentiometer 8, and also includes an X potentiometer 10, a Y potentiometer 12, and an F potentiometer. By combining the three electric displacements with the meter 14, it is possible to determine the relative position of the welding torch 6 with respect to the workpiece 1ff, and from both tracing sensors 5 and 17, the Z-axis, X-axis, Y-axis and F By issuing a correction command for the axis, the welding torch 6 can be directed at a predetermined target angle with respect to the welding line'. It is a requirement of the present invention that the copying sensor 5 is arranged in a specific manner so as to satisfy the following conditions when attached to the rotation axis F. That is, as shown in FIG. 2A, the pointing line of the copying sensor 5 is always made to intersect with the extension line of the radius of curvature at the intersection A to which the welding torch 6 is directed on the welding line'; The line segment BA from this intersection point B to the intersection point A on the weld line' is the X-axis, which is perpendicular to the Z-axis. The two points are that the line length S projected on the horizontal plane including the Y-axis can always be maintained at a constant length. The sensor 5 constantly detects the intersection of the intersecting line formed by the cylindrical surface of the larger diameter than the cylindrical surface and the cylindrical surface of the long-diameter main pipe 2, and the surface including the axis of the short-diameter branch pipe 3 and the tip of the welding torch 6. The goal is to do what is possible.

In order to satisfy the above conditions, for example, the pointing line of the scanning sensor 5 may be directed vertically downward, and the scanning sensor 5 may be arranged so as to be included within the swinging plane of the welding torch 6. can be done.

Next, the z-axis system of the control circuit for automatic profile welding of the welding apparatus will be explained with reference to FIG. The Z-axis control circuit includes a potentiometer 5' as a copying sensor 5,
Potentiometer 30 for origin adjustment provided on the control device side
, a comparison amplifier 32 that generates an output according to the electrical signal difference between both potentiometers 5' and 30, a Z potentiometer 8, a memory 31 provided on the control device side, and a memory operation/control operation. A changeover switch 33 that switches between
, an output amplifier 34, and a Z-axis drive electric motor 7, the operation of which will be explained in detail in the following description of the operation of the welding apparatus tracing operation.

In the tracing welding device having the above configuration, the welding torch 6 becomes a reference on the welding line' by adjusting the five axes of the X-axis, Y-axis, Z-axis, rotation axis F, and the swing axis of the welding torch 6. The origin is aligned so that the object is correctly pointed at the origin and the aiming angle at that time is appropriate.

In the initial state where the home alignment is performed in this way, that is, at the start position, the changeover switch 3 is turned on as shown in Figure 3.
3 is in a state where contact C is closed and contacts A and B are open.

Regarding the control of each axis other than the Z-axis, the copying sensor 17, the rotary axis potentiometer 14, and the X-axis/Y-axis
A control system (not shown) including a sine/cosine potentiometer 21 for controlling the axis, an X potentiometer 10, and a Y potentiometer 12 is used to control the axis at a predetermined speed. Control is performed, and the following Z
We will explain the control of the axes one by one.

In order to determine the start position, first, the electric motor 7 is rotated using the home position adjustment potentiometer 30, and the sensor 5 is set at the start position.

When the position is determined, the value of the z-axis potentiometer 8 at that time is read into the memory 31.

Next, the tracing operation is started, but before the operation, the changeover switch 33 is switched to the side where contacts A and B are closed and contact C is opened.

In any state of sensor 5, each potentiometer 5', 8
, 30 values S2, P2, SZO and the stored value ZM of the memory 31, the following condition is established.

The conversion constant of S2 is AV/熟, and the conversion constant of P2 is b? 7!
11 Set the gain of comparison amplifier 32 to K, and now sensor 5
As a result of the value S2 changing by V volts, the height of X changes and the motor stops again, as is clear from the circuit of FIG. 3.

However, the increase in the value Pz of the potentiometer 8 means that the value S2 increases because the sensor 5 is moved along the Z axis.
Needless to say, this will decrease.

From equations 1 and 2, K(-AX) = BX, so if we transform the above equation, we get: However, as is clear from the above equation, the change in the scanning sensor 5 causes the Z-axis to move up and down in proportion to this. becomes.

Therefore, the displacement that occurs when the tracing sensor 5 moves while contacting a predetermined position of the long-diameter main pipe 2 is output proportionally to the z-axis, and the welding torch 6 is moved in the vertical direction according to the displacement. can be done.

In this case, the contact position of the scanning sensor 5 is located at a position slightly spaced apart from the weld line', and the change in position does not exactly match the vertical displacement of the weld line'.

That is, as is clear from what was shown in Figure 2 A and Town C, there is a concentric circle with a constant distance S between the weld line' and the contact point locus of the copying sensor 5 in Figure A projected on the horizontal plane. On the other hand, when compared on a vertical plane including the radius of curvature, the difference in the Z-axis direction is zero at the top of the main tube 2 as shown in the diagram, but on the vertical plane in the direction orthogonal to this top There is a certain level difference in the Z-axis direction, and at each point in between, that is, 0 and θ〈180
At each point in the range of points, as shown in Figure C,
It is clear that the level difference value increases and decreases in a line-symmetrical manner. In this way, the value in the Z-axis direction detected by the scanning sensor 5 cannot completely match the value in the Z-direction of the weld line' except for the value at the top surface, but the separation distance SG2 (see Figure A) ) was set to a value of about 45 fights, it was found from actual measurements that the maximum error due to this level difference was an error class of about 10-2, which did not pose any problem in practice.

The calculation method will be explained below based on an example with reference to FIGS. 4 and 5.

In FIG. 5, the intersection angle on the horizontal plane between the radius of curvature at any point on the weld line' and the apex generatrix is defined as θ, with the top generatrix of the main pipe 2 as a reference. The level difference Zd in the z-axis direction between a point on the line ' and the top generatrix of the main tube 2 is Zd = Brother - / (P) 2 - (Sho) 2! JJ7r
! ? becomes θ.

Similarly, the level difference Zd' at the contact position of the scanning sensor 5, which is about 45 u away from the welding line' on the horizontal projection plane, is Zd'{-/(K)2-(K')2dn2θ.

By the way, the position where Zd shows the maximum value (Zdmax) is naturally θ=90, that is, Dnθ21, so
Zdmax = parable. 〆^)2-(?)2.

Similarly, Zd'Max = station〆? )2-(Knowledge 2).

1-, and if the welding torch is changed in proportion to Zd/, the position of the welding torch at this time is Zd=(FZ
It is d/.

However, IO: Li-Zdmax/Zd'Max Therefore, the error Δ(θ) between the true height Zd and the approximate value Zd is Δ(
θ): (l/・Zd′(θ)−Zd(θ), 4
Since it is an equation in which nθ is a function, it goes without saying that if the maximum value ΔMax of this Δ(θ) is found, it will be the maximum error value in the Z direction when the welding torch is controlled in proportion to Zd/.

That is, △Max is set so that the horizontal projection movement angle (θ) based on the top generatrix of the main tube is changed up to 900.
It shows the maximum value when calculated time by time using the previous formula △ (θ) = φ7・Zd' (θ) - Zd (θ). 2, the values obtained when the diameter of the branch pipe 3 is changed by 10 mm in the range of 250 to 350 mm are shown in absolute values.

In addition, the value in parentheses shown after the value of ΔMax in FIG. 4 is the horizontal projection movement angle when the maximum error is ΔMax. Next, an actual calculation example is shown below. In this example, the diameter D of the main pipe 2 is 1000U, and the diameter d of the branch pipe 3 is 20U.
This is a case where the diameter d' of the detection position of the 0U1 scanning sensor 5 is 290n. ．．゜． φ7=Zdmax/Zd/Max
=10.1018/21.4863 The above formula △(=φ5
・Zd′(θ)−Zd(θ), 00 to 5=
The results of substituting each value up to 90' in the interval are shown in the table below.

As is clear from the above results, 45R1 on the concentric circle from branch pipe 3! Even if the welding torch is proportionally controlled by a tracing sensor that detects the z-axis position l apart, the error will be maximum when the horizontal projection movement angle is around 45 inches, but the error class will be 10.
It is about -2 and does not pose a practical problem.

As clarified by the above explanation, the present invention aims to improve the three-dimensional phase at the joint of a mutual body formed by a long diameter cylindrical surface and a short diameter cylindrical surface having a mutually orthogonal penetrating relationship. In an apparatus for welding a weld line consisting of a through curve by a welding torch 6 having a multidimensional degree of freedom including the z-axis parallel to the generatrix of the short diameter cylindrical surface, the three-dimensional position of the welding torch 6 is A scanning sensor 5 for detecting the z-axis component of the welding torch 6 is provided on the support shaft on which the welding torch 6 is pivoted, and a cylindrical surface coaxial with the short diameter cylindrical surface and having a larger diameter and the long diameter cylindrical surface are formed. A relative positional relationship is established between the welding torch 6 and the copying sensor 5 such that the copying sensor 5 detects the intersection of the intersecting line and the axis of the short diameter cylindrical surface and the surface including the tip of the welding torch 6. Therefore, the z-axis component can be indirectly detected by the Z-axis direction level detected by the copying sensor 5 at a predetermined position on the long diameter cylindrical surface that is on the outside with respect to the helical tangent. Because of this feature, the scanning sensor can be installed at a location remote from the welding processing position, eliminating the heat effect caused by the arc and demonstrating stable detection performance over a long period of time. It becomes possible.

Moreover, since the copying sensor 5 is always oriented on the extension line of the radius of curvature, it never moves ahead or backwards with respect to the welding torch 6. Therefore, the sensor 5, the torch 6
There is an advantage that not only the control system is simplified because no phase shift occurs at all, but also repeated welding can be easily performed using the reversible method.

Furthermore, compared to the conventional device in which the tracing sensor 5 directly contacts the welding line, multi-layer welding can be performed more easily, making the present invention a truly useful tracing welding device.

[Brief explanation of the drawing]

Fig. 1 is a skeletal diagram schematically showing the basic structure of an example of the device of the present invention, and Fig. 2 A, C, and C are plan views showing the relationship between the weld line on the workpiece and the scanning sensor detection point locus of the device of the present invention. , a front view, a developed view, and FIG. 3 is a main control circuit diagram of the device shown in FIG. FIG. 5 is an explanatory diagram for determining the error in the z-axis direction according to the apparatus of the present invention. 5... Copying sensor, 6... Welding torch, '... Welding line.

Claims (1)

[Claims] 1 Weld line l consisting of a three-dimensional interpenetration curve at the joint of the interpenetrator formed by the long-axis cylindrical surface and the short-axis cylindrical surface having a mutually orthogonal penetrating relationship, is connected to the short-axis cylindrical surface Welding torch 6 with multidimensional degrees of freedom including the Z axis parallel to the generatrix of the surface
In an apparatus for tracing welding, a tracing sensor 5 for detecting the Z-axis component of the three-dimensional position of the welding torch 6 is provided on a support shaft on which the welding torch 6 is pivoted, and The sensor 5 traces the intersection of the intersecting line formed by the cylindrical surface that is coaxial with and has a larger diameter and the longer diameter cylindrical surface, and the axis of the shorter diameter cylindrical surface and the surface that includes the tip of the welding torch 6. A positional relationship is established between the welding torch 6 and the copying sensor 5, and the Z-axis direction level detected by the copying sensor 5 at a predetermined position on the long diameter cylindrical surface that is on the outside with respect to the welding line l. Therefore, the profile welding apparatus is characterized in that the Z-axis component can be detected indirectly.