JP2001071130A - Method and equipment for welding long size work - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate welding distortion by surely imparting an optimal amount of deformation to a long size work and also to reduce cost of equipment by decreasing the number of cylinders. SOLUTION: In a state where the long size work W is positioned and fixed with a clamp 8 for fixing the center of the work, the work is imparted lifting force with actuators 12, 14 and the amount of deformation between supporting parts 6B-6C and 6C-6D are measured with height sensors 18B, 18C. The optimal amount of bending is calculated by a related equation which is preliminarily stored in a height sensor control circuit and the actuators 12, 14 are elevated and lowered by a bending amount control circuit 22 so as to coincide with the optimal amount of bending. Then, the welding of the long size work W between the supporting parts 6B-6C and 6C-6D is executed. When a prescribed cooling time elapses, the actuators 12, 14 are lowered and other actuators 10, 16 are elevated. In the similar way, after executing the calculation of the optimal amount of bending and adjustment by the amount of bending, the welding between the supporting parts 6A-6B and 6D-6E is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding method for reducing welding distortion when welding long works, and an apparatus therefor.

[0002]

2. Description of the Related Art When welding long workpieces, if the welding is performed as it is, if the welding position is deviated from the neutral axis of the workpiece, the workpiece after welding is bent by thermal strain. As a method of preventing such bending, for example, a reverse strain welding method has been developed. FIG. 9 shows the reverse strain welding method.
This will be described with reference to FIG. FIG. 9 is a front view of a reverse strain applying apparatus for performing a reverse strain welding method according to the related art. The reverse strain applying device 62 includes a plurality of support bases 66 to
66, and press-down cylinders 64 to 64 installed directly above the support bases 66 to 66, respectively. When performing the reverse strain welding, a set of long works W to be welded is placed on the support bases 66 to 66 and pushed down by the rods 64 a to 64 a of the pushing down cylinders 64 to 64. In this manner, the long workpiece W is welded by the torch (not shown) in a state in which the predetermined length of reverse strain is applied to the long workpiece W. And the rods 64a to 64a
Rises, and the restraint by the pressing cylinders 64 to 64 is released. As a result, the thermal strain and the reverse strain generated as the long work W is cooled are canceled, and the long work W is straightened to complete the welding.

[0003]

However, in this method, it is difficult to set an optimum amount of distortion (deformation amount) according to characteristics (bending rigidity, presence or absence of reinforcement, etc.) of each work, and it is inevitable that welding is performed. Distortion (bending) remains. Further, in order to carry out this method, a device having a large number of press-down cylinders as shown in FIG. 9 is required, which increases the equipment cost.

Accordingly, in the present invention, a long workpiece can be reliably provided with an optimum amount of deformation to eliminate welding distortion, and the number of cylinders can be reduced to reduce equipment costs. An object of the present invention is to provide a method of welding a work and an apparatus therefor.

[0005]

SUMMARY OF THE INVENTION Therefore, according to the first aspect of the present invention, there is provided a method for welding a long work, wherein the long work is supported by a plurality of support portions along a longitudinal direction. Applying a lifting force to the long work between the plurality of support portions to measure the bending stiffness of the long work between the support portions; and optimal bending using a relational expression from the bending stiffness. A method for welding a long work, characterized in that the amount is calculated, and the calculated optimum bending amount is applied to the long work while welding is performed between the support portions of the long work.

In this welding method, the bending rigidity of each long work between the support portions is measured by applying a lifting force to the long work between the plurality of support portions. The optimum bending amount is calculated from the measured bending stiffness value using a relational expression representing the relationship between the bending stiffness and the optimum bending amount during welding. While providing this optimum bending amount between the support portions of the long work, the support portions of the long work are welded. Therefore, the optimum amount of deformation at the time of welding can always be reliably provided between the support portions of the long work, so that bending after welding can be reliably eliminated. In addition, cylinders for imparting bending amounts to long workpieces are:
One between each supporting part installed at an appropriate distance
Since it is sufficient to provide the cylinders one by one, the number of cylinders can be minimized. In this way, an optimal amount of deformation can be reliably applied to a long workpiece to eliminate welding distortion, and the number of cylinders can be reduced to reduce equipment costs.

Further, in the invention according to claim 2 of the present application, there is provided an apparatus for welding a long work, wherein a plurality of support portions for supporting the long work along a longitudinal direction; An actuator that is disposed between the portions and applies a pushing force to the long work, a bending amount measurement sensor that measures a bending rigidity of the long work by measuring a bending amount by the actuator, A long work welding apparatus has been created, comprising: calculation means for calculating an optimum bending amount using a relational expression; and actuator control means for operating the actuator to apply the calculated optimum bending amount to the long work. .

[0008] In this welding apparatus, actuators are respectively arranged between the plurality of supporting portions, and a pushing force is applied between the supporting portions of the long work by these actuators. The bending amount of the long workpiece when this lifting force is applied is measured by a bending amount measuring sensor,
Thereby, the bending stiffness between the support portions is measured. Then, the calculating means calculates the optimum bending amount using a relational expression representing the relation between the bending rigidity and the optimum bending amount during welding.

Each actuator is operated by the actuator control means, and the optimum bending amount is applied between the support portions of the long work, and the support portions of the long work are welded. Therefore, the optimum amount of deformation at the time of welding can always be reliably provided between the support portions of the long work, so that bending after welding can be reliably eliminated. In addition, an actuator for imparting a bending amount to a long workpiece may be provided between each supporting portion provided at an appropriate interval, so that the number of cylinders can be minimized. it can. In this way, an optimal amount of deformation can be reliably applied to a long workpiece to eliminate welding distortion, and the number of actuators can be reduced to reduce equipment costs.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment Next, a first embodiment of the present invention will be described with reference to FIGS. First, the overall configuration of a welding device for a long workpiece according to the present embodiment will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 1 is a front view showing the entire configuration of a long work welding apparatus of the present embodiment, FIG. 2 is a plan view thereof, and FIG. 3 is a side view thereof. As shown in FIG. 1, a welding device for a long workpiece (hereinafter, also simply referred to as a “welding device”) 2 of the present embodiment includes two pairs of welding torches 4.
A, 4B. The welding torches 4A and 4B are shown in FIG.
And two welding torches on the other side are omitted in the figure.

As shown in FIG. 2, the welding device 2 has support portions 6A, 6A, which support two long works W (an inner inner channel and an outer side rail) W from the upper surface.
6B, 6C, 6D, and 6E. Figure 1
As shown in FIG. 5, a work holding cylinder 8 is provided immediately below the center support portion 6C, and the rod 8a of the work holding cylinder 8 rises, thereby
The long work W is sandwiched and held between C and C. further,
Actuators 10, 12, 14, 16 are provided between the support portions 6A, 6B, 6C, 6D, 6E, respectively. By elevating the rod 10a of the actuator 10, the long workpiece W is pushed up between the support portions 6A and 6B. In addition, the rod 12a of the actuator 12 connects the supporting portions 6B and 6C, the rod 14a of the actuator 14 connects the supporting portions 6C and 6D, and the rod 16a of the actuator 16 supports the supporting portions 6D and 6D.
The space between 6E is pushed up. In this way, a pushing force is applied between the supporting portions of the long workpiece W to measure the bending rigidity, and the supporting portions are pushed up until reaching the optimum bending amount.

As shown in FIG. 1, the push-up amount (bend amount) is measured by height sensors 18A, 18B, 18C, 1 provided in close proximity to the actuators 10-16.
8D. These height sensors 18A
To 18D are rods 10 of each of the actuators 10 to 16.
The stroke amounts a to 16a are detected and transmitted to the height sensor control circuit 24 as electric signals. The height sensor control circuit 24 measures the bending stiffness from the received stroke amount data. Then, the optimum bending amount is calculated from the relational expression between the bending stiffness and the optimum bending amount stored in advance, and is transmitted to the bending amount control circuit 22 as data. In the bending amount control circuit 22, each of the actuators 10, 12, 14, 16 is adjusted to match the received optimum bending amount.
To move the rods 10a, 12a, 14a, 16a up and down.

Further, in the sequence control circuit 20, the actuators are sequentially operated to sequentially push up between the support portions, and the welding robot described below is controlled to perform welding between the pushed up support portions. Let The control of the cooling time of the work from the completion of welding at one place to the welding at the next place is also performed.

Next, the arrangement of the plane of the welding device 2 will be described with reference to FIG. As shown in FIG.
Each of the support portions 6A, 6B, 6C, 6D, and 6E is provided to extend horizontally from a support portion base (not shown) that is erected from the actuators 10, 12, 14, and 16 arranged in a line so as to be shifted upward in the drawing. ing. On the other hand, these support portions 6A-
6E, two pairs of welding robots 26A, 26
6B is installed. The upper two welding robots in FIG. 2 are not shown. These welding robots have welding torches 4A and 4B respectively at the tips of bendable arms. Then, by moving the arm, the welding torches 4A and 4B are moved along the edge of the long workpiece W to perform arc welding.

Next, FIG. 3 will be described. As shown in FIG. 3, as described above, the support base 30 is erected from the actuator 10 to the side. And the support part 6A is fixed on the support part base 30,
It protrudes horizontally. Also, as shown in FIG. 3, the welding torches 4A, 4B (ie, the welding robot 26)
A, 26B) are provided on both sides of the long work W in pairs. These welding torches weld a set of long workpieces W in a box shape.

Next, the above-described height sensor control circuit 2
4 will be described with reference to FIG. FIG. 4 is a graph showing the results of measuring the bending stiffness of the long work W shown in FIG. 1 at two locations. As shown in FIG. 4, the amount of deformation when the support 14 is pushed up by the actuator 14 between the support portions 6C and 6D and the support portion 6B
The amount of deformation when the actuator 12 pushes up between −6C is measured by changing the pushing up force. “Reinforced” indicates the measurement result between the support portions 6C and 6B when a reinforcing material is placed inside the long box-shaped work W. As described above, the amount of deformation is measured by the height sensor provided for each actuator.

From this measurement result, it can be seen that the amount of deformation is almost directly proportional to the pressing force (push-up force). Further, it can be seen that the supporting portions 6C-6D have a larger deformation amount, that is, a lower bending rigidity, than the supporting portions 6B-6C. Of course, in the case of "with reinforcement", the deformation amount is smaller and the bending rigidity is larger than in the case without reinforcement.

Next, the relationship between the bending rigidity and the optimum bending amount at the time of welding will be described with reference to FIG. FIG. 5 is a graph showing the relationship between the bending rigidity and the optimum bending amount. This graph is created as follows. First, in the case of "with reinforcement", welding is actually performed while giving various amounts of bending by the actuators between the support portions 6B and 6C and between the support portions 6C and 6D, and the optimum bending without welding distortion remains. Find the quantity. Then, from the data obtained in FIG. 4, the amount of deformation when the applied pressure is 2000 N is taken as the bending stiffness X on the horizontal axis, and the optimum bending amount Y obtained by experiment is taken on the vertical axis. Then, when plotting each of the above three cases, a graph shown in FIG. 5 is obtained.

The three data obtained in this way are substantially aligned on a straight line as shown in FIG.
It is shown by the relational expression X-5. Therefore, the optimum bending amount can be determined from this relational expression even when welding between other supporting portions or even other long workpieces. That is,
First, the support between the long workpieces is pushed up by a pushing force of 2000 N, and a deformation amount at that time is obtained as a bending rigidity X. Then, the value of Y obtained by substituting the value of X into the above relational expression is the optimum bending amount. By deforming the supporting portions by the optimum bending amount obtained in this manner and performing welding, welding of a long work can be performed while reliably preventing welding distortion.

Next, a specific procedure of the method for welding a long workpiece will be described with reference to FIGS.
FIG. 6 is a flowchart showing the procedure of the method for welding a long workpiece according to the present embodiment. First, in step S10, the rod 8a of the work center fixing clamp (work holding cylinder) 8 is lifted to pinch and fix the long work W between the support 8 and the support 6C. Next, in step S12,
Actuator 12 and rod 12 of actuator 14
a and 14a rise to apply a pushing force of 2000 N to the long work W. And the support portions 6B-6C at this time
The height of the long work W between the intervals 6C and 6D is measured by the height sensors 18B and 18C, respectively.

The data of the measured deformation is represented by a bending rigidity X
Is input to the height sensor control circuit 24. In the height sensor control circuit 24, the relational expression Y = 3X−
5, the optimum bending amount Y is calculated.
Is input to the bending amount control circuit 22. In the bending amount control circuit 22, the rods 12a and 14a are moved up and down by controlling the actuators 12 and 14, respectively, so as to match the optimum bending amount. Height sensor 18
Rods 12a and 14a input from B and 18C to the bending amount control circuit 22 via the height sensor control circuit 24
When the stroke value of each corresponds to the optimal bending amount,
The actuators 12, 14 are fixed at that position. Then, welding between the support portions 6B-6D is performed. Specifically, the support portions 6C and 6B are welded by the pair of welding torches 4A, and the support portions 6C and 6D are welded by the pair of welding torches 4B.

When a predetermined cooling time has elapsed after the completion of welding, the process proceeds to step S14, where the sequence control circuit 2
From 0, a control signal is output to each actuator, and the rods 12a and 14a of the actuators 12 and 14 descend. At the same time, the rods 10a,
16a rises to apply a pushing force of 2000N to the long work W. Then, between the support portions 6A and 6B at this time,
The amount of deformation of the long workpiece W between 6D and 6E is measured by the height sensors 18A and 18D, respectively.

Thereafter, in the same manner as in step S12, the height sensor control circuit 24 and the bending amount control circuit 22 calculate the optimum bending amount and adjust the bending amount. The support portions 6A and 6B are welded by a pair of welding torches 4A, and the support portions 6D and 6E are welded by a pair of welding torches. After the completion of the welding and the prescribed cooling period,
Proceeding to step S16, the actuators 10, 16
The rods 10a and 16a of the workpiece lower and the rod 8a of the work center fixing clamp 8 also lowers. Then, the long work W is taken out, and one welding operation is completed.

As described above, in the method and apparatus for welding a long workpiece according to the present embodiment, the actuator is pushed up by applying a predetermined pushing force between the respective supporting portions, and the deformation at that time is represented by bending rigidity data. Take in as. Then, the optimum bending amount between the support portions is calculated from the relational expression obtained in advance, and the actuator is controlled so as to achieve the bending amount. Then, welding is performed with a welding torch, and after a predetermined cooling time has elapsed, the actuator is released. by this,
It is possible to reliably eliminate welding distortion.

As an effect peculiar to this embodiment, a long work is clamped by the center support portion 6C and the cylinder 8 for positioning the work. However, since both ends are free, thermal expansion in the longitudinal direction during welding can be prevented. Since the shrinkage during cooling is not restricted, the total length shrinkage of the finished product can be reduced.

In this embodiment, the number of the supporting portions is five, but the number of the supporting portions may be any number according to the length of the long work. Also, in the present embodiment, FIG.
As described above, a case where a long linear workpiece is welded has been described, but a long workpiece curved in a plane can also be welded.

Second Embodiment Next, a second embodiment embodying the present invention will be described with reference to FIGS. FIG. 7 is a front view showing the entire configuration of the welding device for a long workpiece according to the present embodiment. As shown in FIG. 7, a welding device for a long workpiece according to the present embodiment (hereinafter, also simply referred to as “welding device”) 32.
Is provided with two pairs of welding torches 34A, 34B. There are two welding torches 34A and 34B, and the other welding torch is not shown.

As shown in FIG. 7, the welding device 32 includes a support portion 36 for supporting a pair of long works W from the top. A work center fixing clamp 38 is provided directly below the support portion 36, and the rod 38 a of the work center fixing clamp 38 is raised, thereby holding and holding the long work W between the support portion 36. I do. Further, on both sides of the work center fixing clamp 38,
Four fulcrum lifting cylinders 40, 4 at regular intervals
2, 44, 46 are arranged. Rods 40a, 42 of these fulcrum lifting cylinders 40, 42, 44, 46
The elongate work W is pushed up to the supporting position by a rise of a, 44a and 46a.

Pressing bending actuators 56A and 56B are provided at positions corresponding to both ends of the long work W, respectively. These press bending actuators 56
When the rods 56a and 56b of A and 56B descend, the bending amount is given to the central portion of the long work W. Further, these press bending actuators 5
Immediately below 6A and 56B, height sensors 48A and 48 are provided.
B are provided respectively. These height sensors 48A, 48B are provided with the respective pressing bending actuators 56A,
The stroke amounts of the rods 56a and 56b of the 56B are detected and transmitted to the height sensor control circuit 54 as electric signals.

In the height sensor control circuit 54,
The bending stiffness is measured from the received stroke amount data. Then, the optimum bending amount is calculated from the relational expression between the bending stiffness and the optimum bending amount stored in advance and transmitted to the bending amount control circuit 52 as data. The bending amount control circuit 52 controls the pressing bending actuators 56A and 56B so that the rod 56
a, 56b is moved up and down.

Further, in the sequence control circuit 50, the fulcrum lifting cylinders are sequentially operated to sequentially change the bending support points, and the welding robot (not shown) is controlled to bend by the welding torches 34A and 34B. Welding of the part that is. Further, after the welding is completed, the cooling time is controlled from the time when the press-down bending actuators 56A and 56B are raised and the fulcrum lifting cylinder is lowered to release the long work W.

As described above, in the welding device 32 of the present embodiment, unlike the first embodiment, instead of giving the amount of bending by raising the fixed support portion with the actuator, the pressing-down actuator is used. The bending amount is given by pushing down both ends of the long work W at 56A and 56B. And by taking such a configuration,
Since the fixed support portion can be formed only in the support portion 36 at the center, there is an advantage that the removal of the long workpiece W after the welding is completed becomes extremely easy.

Next, a specific procedure of the method for welding a long workpiece according to the present embodiment will be described with reference to FIGS. FIG. 8 is a flowchart showing the procedure of the method for welding a long workpiece according to the present embodiment. First, step S20
As a result, the rod 38a of the work center fixing clamp 38 is lifted, and the long work W is sandwiched between the support portion 36 and positioned and fixed. Next, in step S22, the rods 42a and 44a of the fulcrum lifting cylinders 42 and 44 rise,
The long work W is kept horizontal. At this time, the rods 40a and 46a of the fulcrum lifting cylinders 40 and 46 are at the lowered position, and are not in contact with the long workpiece W.

Subsequently, the press bending actuator 56A,
The rods 56a and 56b of 56B descend and push down both ends of the long workpiece W with a predetermined pushing force. The pushing amount at this time is measured by the height sensors 48A and 48B. The data of the measured depression amount is input to the height sensor control circuit 54 as bending rigidity. Then, the optimum bending amount is calculated by a relational expression stored in advance, and the value of the calculated optimum bending amount is input to the bending amount control circuit 52. In the bending amount control circuit 52, the press-down bending actuators 56A and 5B are adjusted so as to match the optimum bending amount.
6B is controlled to move the rods 56a and 56b up and down.

When the values of the push-down amounts measured by the height sensors 48A and 48B respectively match the optimum bending amounts,
The welding between the fulcrum lifting cylinders 42 and 44 is performed.
Specifically, the pair of welding torches 34A welds between the support portions 36 and the fulcrum lifting cylinders 42, and the pair of welding torches 34B welds between the support portions 36 and the fulcrum lifting cylinders 44. After the completion of welding and the prescribed cooling time,
In step S24, a control signal is output from the sequence control circuit 50 to each actuator, and the rods 56a and 56b of the push-bend actuators 56A and 56B move up. Subsequently, the rods 42a and 44a of the fulcrum lifting cylinders 42 and 44 are lowered, and the rods 40a and 46a of the fulcrum lifting cylinders 40 and 46 are raised to hold the long workpiece W in a horizontal state.

Subsequently, the depression actuators 56A, 5A
The 6B rods 56a and 56b move down to
Are pushed down by a predetermined pushing force, and the pushing amount is measured by the height sensors 48A and 48B. Then step S
Similarly to 22, the height sensor control circuit 54 and the bending amount control circuit 52 calculate the optimum bending amount and adjust the bending amount. Then, the fulcrum lifting cylinder 42-
A pair of welding torches 3 is provided between the press bending actuators 56A.
4A, the fulcrum lifting cylinder 44 and the pressing bending actuator 56B are welded by a pair of welding torches 34B.

After the completion of the welding and a predetermined cooling period has elapsed, the process proceeds to step S26, in which the rods 56a and 56b of the push-down bending actuators 56A and 56B rise, and the rods 40a and 46a of the fulcrum lifting cylinders 40 and 46. Descends. Then, the rod 38a of the work center fixing clamp 38 is lowered, and the long work W is released, and is taken out of the welding device 32. Thus, one welding is completed.

In this embodiment, the number of the fulcrum lifting cylinders is four, but the number of the fulcrum lifting cylinders may be any number according to the length of the long work.

In each of the above embodiments, each of the actuators and the cylinders is arranged in the vertical direction so that the long work W
However, it is also possible to arrange the actuators and cylinders in the horizontal direction and also to incline the long work W in the horizontal direction so as to apply the bending amount in the horizontal direction. The other steps of the method for welding a long workpiece and the configuration, shape, dimensions, quantity, connection relationship, and the like of other parts of the welding device for a long workpiece are not limited to the above embodiments.

[0040]

According to the present invention, an optimum amount of deformation can be reliably applied to a long workpiece to eliminate welding distortion, and the number of cylinders can be reduced to reduce equipment costs.

[Brief description of the drawings]

FIG. 1 is a front view showing the entire configuration of a welding apparatus for a long work according to a first embodiment of the present invention;

FIG. 2 is a plan view thereof.

FIG. 3 is a side view thereof.

FIG. 4 is a view showing a result of measuring a bending rigidity of a long work in the first embodiment.

FIG. 5 is a diagram illustrating a relationship between bending rigidity and an optimum bending amount in the first embodiment.

FIG. 6 is a flowchart showing a procedure of a method for welding a long workpiece in the first embodiment.

FIG. 7 is a front view showing the entire configuration of a welding apparatus for a long work according to a second embodiment of the present invention;

FIG. 8 is a flowchart illustrating a procedure of a method for welding a long workpiece according to the second embodiment.

FIG. 9 is a front view of a reverse strain applying apparatus for performing a conventional reverse strain welding method.

[Explanation of symbols]

6A, 6B, 6C, 6D, 6E, 36, 40, 42, 4
4, 46 Support part 10, 12, 14, 16, 56A, 56B Actuator 18A, 18B, 18C, 18D, 48A, 48B Bending amount measuring sensor 24, 54 Calculation means 22, 52 Actuator control means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takashi Nakagawa 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Takeyuki Tateyama 5-14 Midorigaoka, Toyota City, Aichi Prefecture Daitosei Machine Co., Ltd. (72) Inventor Kazuki Iwata 5-14 Midorigaoka, Toyota-shi, Aichi F-term (reference) 4E081 AA10 BA40 DA30 EA45 EA54 EA56

Claims (2)

[Claims] 1. A method for welding a long work, wherein the long work is supported by a plurality of support portions along a longitudinal direction of the long work, and a pushing force is applied to the long work between the plurality of support portions. Measuring the bending stiffness of the long work between the supporting portions, calculating an optimum bending amount using a relational expression from the bending stiffness, while giving the calculated optimum bending amount to the long work. A method for welding a long work, which welds between the support portions of the long work. 2. An apparatus for welding a long work, comprising: a plurality of support portions for supporting the long work in a longitudinal direction thereof; and a plurality of support portions disposed between the plurality of support portions to push up the long work. An actuator for applying a force, a bending amount measuring sensor for measuring a bending stiffness of the long work by measuring a bending amount by the actuator, and a calculating means for calculating an optimum bending amount from the bending stiffness using a relational expression And a controller for operating the actuator to apply the calculated optimum bending amount to the long workpiece.