JP6269976B2 - Abnormality detection method in U-shaped press molding machine, abnormality detection device and U-shaped press molding method, U-shaped press molding machine - Google Patents

Description

  The present invention relates to an abnormality detection method, an abnormality detection apparatus, a U-shaped press based on the above-described method and apparatus in a Kaiser type U-shaped press forming machine that press-forms a steel sheet into a U shape when manufacturing a UOE steel pipe from the steel sheet. The present invention relates to a molding method and the U-shaped press molding machine.

  UOE steel pipes are mainly used for line pipes for transporting oil and natural gas, steel pipes for building materials, marine structures, and the like. The above UOE steel pipe is usually subjected to bending processing with a crimping press at the end of the steel plate, which is the material of the steel pipe, then pressed into a U shape, formed into an O shape to form a raw pipe, and the butt portion is welded It is manufactured by expanding the tube and increasing the roundness.

  The U-shaped press forming apparatus is roughly classified into a Kaiser type and a Barson type (see, for example, Patent Document 1). As shown in FIG. A main cylinder 2 that presses the steel plate 1 from above, a punch beam 3 that is connected to the main cylinder and that is detachably attached to the lower end of the die 3a that is in direct contact with the steel plate at the time of press forming; A retract cylinder 4 supported from below, two brake rolls 5 for restraining the material steel plate from both sides, and two brake garters 6 for supporting the brake rolls are provided. The retract cylinder and the brake garter are connected by a link arm 7 and have a structure that expands and contracts the opening degree between the two brake garters as the retract cylinder moves up and down.

  FIG. 2 shows the AA ′ cross section of FIG. 1. When the main cylinder 2 extends, the punch beam 3 connected to the lower end of the main cylinder descends and the width center of the material steel plate 1 is lowered. Press the part down. When the steel plate is pushed down by the punch beam 3, the steel plate 1 comes into contact with the retract cylinder 4 and pushes down the retract cylinder. Since the retract cylinder 4 is connected to the brake garter 6 by the link arm 7, when the retract cylinder 4 is lowered, the brake garter 6 is drawn toward the line center side. As a result, the steel plate 1 is subjected to three-point bending by the punch beam 3 and the brake rolls 5 on both side surfaces, and is formed into a U shape.

  Since the steel plate used as the material of the UOE steel pipe is long, the punch beam and brake roll for forming the steel plate into a U shape have a length longer than that of the steel plate. For this reason, there are two main cylinders connected to the punch beam and two retract cylinders connected to the brake garter for supporting the brake roll at both ends of the punch beam and the brake garter in the length direction (steel plate length direction). It is usual that it is arranged. In the U-shaped press forming machine shown in FIG. 1, a steel plate as a raw material is carried in from one side in the length direction of the punch beam, formed into a U shape, and then carried out in the opposite direction. Therefore, in the present invention, for convenience of explanation, the two main cylinders and the retract cylinders that are respectively provided are referred to as an input side main cylinder, an output side main cylinder, an input side retract cylinder, and an output side retract cylinder.

JP 2008-246533 A

  By the way, in recent years, pipelines for oil and gas transportation tend to be transported at high pressure in order to enable long-distance transportation. In addition, the development of oil and gas fields has progressed, and the number of cases transported in harsh environments such as cold regions and deep seabeds is increasing. Furthermore, steel pipes for buildings and steel structures are required to have excellent seismic resistance as a countermeasure against huge earthquakes. Under such circumstances, in recent years, UOE steel pipes have been increased in strength and thickness, and the load on the U-shaped press forming machine is also increasing. For this reason, the U-shaped press forming machine tends to be damaged more frequently due to an excessive load caused by an abnormal tilt of the punch beam in the longitudinal direction of the steel plate and an abnormal opening of the brake garter in the longitudinal direction of the steel plate.

  However, in the Kaiser-type U-shaped press molding machine that forms a U-shape by bending a steel plate at three points by a brake roll disposed on both sides of the punch beam and the punch beam, the punch beam has been initially inclined Control, that is, when the punch beam is tilted above a predetermined threshold before the start of pressing, the tilt of the punch beam in the longitudinal direction of the steel sheet is adjusted by adjusting the amount of movement of the main cylinder arranged in the longitudinal direction of the steel sheet. As for the brake garter that supports the brake roll, only the initial position is set, and the opening control during the press is not performed. It is difficult to detect.

  In addition, as steel pipes are becoming stronger and thicker in recent years, the production range of steel pipes is diversified, so the load on the U-shaped press forming machine changes in the strength, thickness, length, etc. of the steel sheet. Therefore, it is necessary to switch the molding conditions in accordance with them. However, it is not possible to cope only with the tilt control of the punch beam and the initial position setting of the brake garter.

  The present invention has been made in view of the above-mentioned problems of the prior art, and its purpose is to detect an abnormality of the U-shaped press molding machine at an early stage and prevent damage to the U-shaped press molding machine. Abnormality detection method, abnormality detection device and method, and U-type press molding method based on the device, and U-shape, which can change the press molding conditions according to the load condition applied to the shape press molding machine It is to propose a press molding machine.

  The inventors have intensively studied to solve the above problems. As a result, in addition to the punch beam tilt control and initial setting of the brake garter, the stroke difference in the longitudinal direction of the steel plate of the main cylinder (inlet main cylinder and outlet main cylinder), the longitudinal direction of the brake garter steel plate Side-exit direction) and the stress applied to the link arm are constantly measured during the entire press process, and when any one or more of these values exceeds a predetermined threshold value The inventors have found that it is effective to determine that an abnormality has occurred and have developed the present invention.

  That is, the present invention relates to a punch beam that moves up and down by a main cylinder, a wrist-like cylinder disposed below the punch beam, and two brakes supported by a brake garter connected to the wrist-like cylinder by a link arm. A method of detecting an abnormality in a U-shaped press forming machine that presses a steel plate into a U shape by a roll, wherein the stroke difference in the longitudinal direction of the main cylinder measured by a displacement sensor installed in the main cylinder, One or more values of the opening difference in the longitudinal direction of the steel plate of the brake garter measured by the installed opening sensor and the stress applied to the link arm measured by the stress sensor installed on the link arm are Abnormality detection of a U-shaped press molding machine that determines an abnormality when a predetermined threshold value is exceeded It is a method.

  The present invention also provides a punch beam that moves up and down by a main cylinder, a wrist-like cylinder disposed below the punch beam, and two brakes supported by a brake gutter connected to the wrist-like cylinder by a link arm. An abnormality detection device in a U-shaped press forming machine that press-rolls a steel sheet into a U shape by a roll, and a displacement sensor that measures the stroke of the main cylinder, and an opening that measures the degree of opening of the brake gutters on both sides A sensor and a stress sensor for measuring the stress applied to the link arm, the stroke difference in the longitudinal direction of the steel plate of the main cylinder measured by the displacement sensor, the opening difference in the longitudinal direction of the steel plate of the brake gutter measured by the opening sensor And any stress applied to the link arm measured by the stress sensor. When more than one value becomes a predetermined threshold or more, an abnormality detection device abnormality determining U-shaped press-molding machine.

  The abnormality detection device for the U-shaped press molding machine according to the present invention is characterized in that an abnormality alarm is issued when it is determined as abnormal.

  Further, according to the present invention, when an abnormality is detected by the above-described abnormality detection device, the operation is switched to a press operation for reducing the load applied to the U-shaped press molding machine, or the press molding machine is repaired. This is a shape press molding method.

  Moreover, this invention is a U-shaped press molding machine provided with said abnormality detection apparatus.

  According to the present invention, it is possible to detect an abnormality of the U-shaped press molding machine at an early stage and prevent damage to the U-shaped press molding machine, to switch the press molding condition to a low load operation, and to repair the press molding machine. Implementation choices can be made quickly. Therefore, according to the present invention, it is possible to reduce the operation stop time due to the damage of the U-shaped press molding machine and to greatly improve the operation rate.

It is a figure explaining the structure of a Kaiser type U-shaped press molding machine. It is a figure explaining the shaping | molding mechanism of a Kaiser type U-shaped press molding machine. It is a figure explaining the inclination abnormality of a punch beam. It is a figure explaining the opening degree abnormality of a brake garter. It is a figure explaining the damage of the U-shaped press molding machine caused by the inclination abnormality of a punch beam and the opening degree abnormality of a brake garter. It is a figure explaining the position of the various sensors installed in a U-shaped press molding machine. It is a figure which shows an example which measured the inclination abnormality of a punch beam. It is a figure which shows an example which measured the opening abnormality of the brake garter. It is a figure which shows an example which measured the stress concerning a link arm. It is a figure explaining an example of the abnormality determination processing flow of this invention.

Abnormalities that can occur in a Kaiser-type U-shaped press molding machine (hereinafter, also simply referred to as “press molding machine”) are broadly classified into an abnormal tilt of a punch beam and an abnormal opening of a brake garter (brake roll).
FIG. 3 is a diagram for explaining the tilt abnormality of the punch beam. As shown in FIG. 3 (a), the strokes of the main cylinders on the inlet side and the outlet side during press forming are the same, and the punch beam is in the length direction of the steel plate. In the case of uniform lowering, that is, when the strokes of the entry-side main cylinder and the exit-side cylinder are the same, the press load applied to the steel plate is directed downward, but as shown in FIG. If there is a difference between the strokes of the main cylinders on the entry side and the exit side, the punch beam will not be uniformly lowered in the length direction of the steel sheet but will be inclined. When the punch beam is tilted as described above, the press load applied to the steel sheet does not go directly below, and a thrust force is generated in the length direction of the steel plate against the press forming machine. Not only is an unbalanced load applied to one of the two retracted cylinders, but an unbalanced load is also applied within a single retract cylinder. As a result, as shown in FIGS. 5A and 5B, the bolster installed on the upper part of the retract cylinder is damaged, or the retract cylinder is leaked.

  FIG. 4 is a diagram for explaining an abnormal opening of the brake garter (brake roll). As shown in FIG. 4A, the opening of the brake garter is normal, that is, the opening of the brake garter is the length of the steel plate. If it is the same in the vertical direction, the press reaction force against the brake garter (brake roll) during pressing is only the force in the direction perpendicular to the steel plate length direction, but as shown in FIG. When a difference occurs in the opening direction of the brake garter in the steel plate length direction, a component force in a direction different from the direction perpendicular to the steel plate length direction is generated. Therefore, a bending stress is applied to the link arm that connects the retract cylinder and the brake garter and the screw shaft that changes the initial position of the brake garter, as shown in FIGS. 5 (c) and 5 (d). Causes fatigue and breakage of the link arm and screw shaft. Further, when the opening degree of the brake garter as described above occurs, a difference occurs in the molding load on the entry side and the exit side, which also causes an abnormality in the tilt of the punch beam.

  Therefore, if the above abnormalities occur, the steel sheet cannot be accurately pressed and the manufacturable range of the steel pipe is narrowed, and an abnormal load is applied to the press forming machine. This will cause damage to the molding machine and cause a great influence on the production of UOE steel pipes.

  Therefore, the present invention detects the abnormality of the U-shaped press molding machine at an early stage and prevents the press molding machine from being damaged. In addition to the conventional punch beam initial tilt control and brake garter initial position setting, The stroke difference between the main cylinder on the entry side and the exit side, the opening difference in the longitudinal direction of the steel plate of the brake garter, and the stress applied to the link arm are constantly measured, and one or more of these values are predetermined. It was decided to be abnormal when the threshold was reached.

First, means for detecting an abnormal tilt of the punch beam during pressing will be described.
As shown in FIG. 6 (a), the punch beam tilt abnormality is caused by installing a displacement sensor for measuring the stroke (displacement) of the cylinder shaft in the two main cylinders on the entry side and the exit side. The cylinder stroke is constantly measured, and it is determined that a tilt abnormality has occurred when the difference between the strokes of the inlet and outlet main cylinders exceeds a predetermined threshold value. In FIG. 6B, as a displacement sensor, a differential transformer type displacement meter is installed with the iron core on the fixed side (cylinder body) and the differential transformer (coil) on the movable side (cylinder rod). An example is shown.

  FIG. 7B shows, as shown in FIG. 7A, the strokes of the two main cylinders on the inlet side and the outlet side during the entire pressing process when the steel sheet is formed into a U shape by two presses. This shows an example of the result of measuring with a displacement sensor. In this example, in the first press, a large difference was not detected in the strokes of the main cylinders on the entry side and the exit side, but moved to the standby position during the transition from the end of the first press to the second press. A stroke difference of about 50 mm occurs at each stage, and a stroke difference of up to 78 mm occurs during the subsequent second press. However, in both the first press and the second press, there is no significant difference between the strokes at the position where the cylinder is extended (the position where the punch beam is lowered most). This is because it is not possible to detect the abnormal tilt of the punch beam during the press as described above only by measuring the tilt at the position where the punch beam is most lowered. Therefore, in order to reliably detect the abnormal tilt of the punch beam. This shows that constant measurement of the stroke of the main cylinder is necessary.

Here, the displacement sensor for measuring the stroke (displacement) of the cylinder shaft does not need to be a special one, and in addition to the differential transformer type displacement meter shown in FIG. A meter, a capacitance type displacement meter, or the like can be used.
The installation position of the displacement sensor is not limited to the main cylinder as shown in FIG. 6. For example, the displacement sensor may be installed on the punch beam itself as long as it does not hinder the press work.

Next, a means for detecting an abnormal opening of the brake garter during pressing will be described.
As means for detecting an abnormal opening of the brake garter, as shown in FIG. 6, both ends of the steel plate length direction of the two brake garters arranged on both sides of the punch beam (incoming side and outgoing side) Side) is installed with an opening sensor that measures the opening (distance), constantly measures the opening (distance) of the brake garter on the entry and exit sides during the press, and enters and exits on the entry and exit sides during the press. When the opening degree difference exceeds a predetermined threshold value, it is determined that an opening degree abnormality has occurred.

  FIG. 8 shows a measurement example of the opening difference of the brake garter when the steel sheet is press-formed into a U shape by two presses as in FIG. 7, and FIG. A normal example in which the difference in opening is 3 mm or less throughout the press, and FIG. 8B shows an abnormality in the opening of the brake gutter (opening opening> opening opening). This shows an example of 17 mm in the entire press process.

Here, as the opening sensor of the brake gutter, in addition to the above-described differential transformer displacement meter, a displacement meter using a vortex sensor, a commercially available laser distance meter, or the like can be used. In FIG. 6C, a differential transformer type displacement meter is used as a displacement sensor, the iron core is on the fixed side (press molding machine main body side), and the differential transformer (coil) is on the movable side (lower brake garter). An example of installation was shown.
Further, as shown in FIG. 6, the position of the opening sensor is not limited to the vicinity of the main cylinder of the brake garter, and may be installed at both ends of the brake garter, for example.

  By the way, when the above opening abnormality of the brake garter occurs, bending stress is applied to the link arm and the screw shaft by the press reaction force applied to the brake garter as shown in FIG. However, the brake garter opening sensor described above cannot measure the absolute value of the stress (tensile stress + bending stress) applied to the link arm or the like. Therefore, in addition to the opening sensor of the brake garter, a stress sensor is installed on the side of the link arm, the stress applied to the link arm is measured, and when the stress exceeds a predetermined threshold value, It is determined that an abnormality has occurred.

  FIG. 9 is an example of the result of measuring the stress applied to the link arm when the opening degree of the brake garter is normal and abnormal when the steel sheet is pressed into a U shape by two presses, as in FIG. The peak value of the stress applied to the link arm when the opening is abnormal is about 1.5 times that of normal because bending stress is applied in addition to the normal press reaction force. Recognize. When such excessive stress is repeatedly applied, the link arm breaks or causes fatigue failure.

  Note that the measurement of the stress applied to the link arm is not only effective for the above-described determination of the opening degree abnormality, but also effective for preventing damage to the press forming machine due to increasing the strength and thickness of the UOE steel pipe. That is, with the recent increase in strength and thickness of the steel sheet used as the material for the UOE steel pipe, the load applied to the press molding machine has also increased, but the stress applied to the link arm is measured, and the above stress is a predetermined threshold value. When this occurs, for example, the press molding machine can be prevented from being damaged by switching to a low-load operation that reduces the press speed from one press to two presses or reducing the press speed. be able to. Further, by adopting the above press molding method, it is possible to estimate the load applied to the press molding machine, which is effective in expanding the moldable range.

Here, the stress sensor need not be special, and a commercially available strain gauge or the like can be used.
The stress sensor may be installed on the screw shaft instead of the link arm or in addition to the link arm.

Next, the abnormality determination processing flow in the abnormality detection method or abnormality detection apparatus of the U-shaped press molding machine will be described with reference to FIG.
(Step 1)
The U-shaped press molding machine is equipped with a displacement sensor that measures the stroke on the main cylinder, an opening sensor that measures the opening of the brake garter, and a stress sensor that measures the stress applied to the link arm. The main cylinder cylinder stroke difference, the opening difference of the brake garter in the longitudinal direction of the steel plate, and the stress applied to the link arm are constantly measured, and the measurement results are collected on the machine-side PC.
(Step 2)
From the aggregated data, find the maximum value of the stress applied to the link arm, compare this value with a predetermined reference value (threshold value), and if it is less than the reference value, determine that it is normal and continue press forming. If the value is equal to or greater than the reference value, it is determined that the stress is abnormal. At the same time, a stress abnormality alarm may be issued to an operator of the press molding machine and / or a maintenance department of the press molding machine.
(Step 3)
Next, the maximum values of the stroke difference and the brake garter opening difference are determined for the main cylinder in the press determined to be abnormal, and these values are compared with predetermined reference values (thresholds), both of which are less than the reference values. If it is normal, press molding is continued, and if any one or more of the above values is equal to or greater than the reference value, it is determined that there is an abnormality, and an inclination abnormality alarm and / or an opening degree abnormality alarm is displayed as an operator of the press molding machine. And / or to the maintenance department of the press molding machine.
(Step 4)
Next, when it is determined in step 3 that the stress is abnormal, the following measures are taken according to the level of abnormality. For example, if it is judged that the level of abnormality is small and the effect on press molding accuracy is small, the press molding condition is switched from one press to two presses, or the press speed is reduced. Switch to a low-load operation that reduces the load on the molding machine. On the other hand, when it is determined that the level of abnormality is large and it is difficult to continue the press operation, the press operation is interrupted and the press molding machine is repaired.

  When an abnormality alarm is issued, it is possible to effectively prevent damage to the press molding machine due to an abnormality in the tilt of the punch beam and an abnormality in the opening degree of the brake garter by taking the measures as in step 4 above. Furthermore, even if there is no punch beam tilt abnormality or brake garter opening abnormality, it is possible to expand the moldable range by adopting low-load operation that reduces the stress applied to the link arm to a predetermined threshold or less. It becomes.

  Note that the above abnormality determination processing flow is an example of an embodiment of the present invention, and is not limited to the above example. For example, the abnormality determination of the inclination of the punch beam and the opening of the brake garter shown in the flow of FIG. 10 may be performed prior to the abnormality determination of the stress of the link arm, the inclination of the punch beam, the opening difference of the brake garter, You may perform the abnormality determination of the stress of a link arm simultaneously. Further, the abnormality determination of the inclination of the punch beam and the opening difference of the brake garter may be performed in separate steps.

  Here, the threshold value used for the abnormality determination is the threshold value for determining the abnormality of the tilt of the punch beam, the threshold value for determining the abnormality of the opening difference of the brake garter, and the threshold value for determining the abnormality of the link arm stress. Based on the specifications, it is preferable to set by performing a calculation considering the fatigue limit.

1: Material steel plate 2: Main cylinder 3: Punch beam 3a: Mold 4: Retract cylinder (saddle)
5: Brake roll 6: Brake gutter 7: Link arm 8: Screw shaft

Claims (5)

A punch beam that moves up and down by two main cylinders installed on the steel plate inlet side and the steel plate outlet side of the press machine ;
Two wrist-like cylinders disposed below the punch beam;
A U-shaped press that is connected to the respective wrist-like cylinders by link arms and press-molds a steel sheet into a U-shape by two brake rolls supported by brake garters arranged opposite to both sides of the punch beam. An abnormality detection method in a molding machine,
The stroke difference in the longitudinal direction of the steel plate of the main cylinder measured by the displacement sensor installed in the two main cylinders,
The opening difference in the longitudinal direction of the steel plate of the brake garter measured by the opening sensor installed on both ends of the steel plate length direction of the brake garter, and
Stress applied to the link arm measured by a stress sensor installed on the link arm,
An abnormality detection method for a U-shaped press molding machine that determines an abnormality when any one or more of the values is equal to or greater than a predetermined threshold value. A punch beam that moves up and down by two main cylinders installed on the steel plate inlet side and the steel plate outlet side of the press machine ;
Two wrist-like cylinders disposed below the punch beam;
A U-shaped press that is connected to the respective wrist-like cylinders by link arms and press-molds a steel sheet into a U-shape by two brake rolls supported by brake garters arranged opposite to both sides of the punch beam. An abnormality detection device in a molding machine,
A displacement sensor for measuring the strokes of the two main cylinders;
An opening degree sensor for measuring the opening degree on both ends in the steel plate length direction of the brake garter on both side surfaces,
A stress sensor for measuring the stress applied to the link arm;
Stroke difference in the longitudinal direction of the main cylinder measured with the displacement sensor,
The opening difference in the longitudinal direction of the steel plate of the brake gutter measured by the opening sensor, and
The stress applied to the link arm measured by the stress sensor,
An abnormality detection device for a U-shaped press molding machine that determines an abnormality when any one or more of the values is equal to or greater than a predetermined threshold value. The abnormality detection device for a U-shaped press molding machine according to claim 2, wherein an abnormality alarm is issued when it is determined as abnormal. When an abnormality is detected by the abnormality detection device according to claim 2 or 3, switching to a press operation for reducing a load applied to the U-shaped press molding machine or repairing the press molding machine is performed. Shape press molding method. A U-shaped press molding machine comprising the abnormality detection device according to claim 2.

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