JP6422390B2 - Apparatus and method for producing bent steel by three-dimensional hot bending and quenching - Google Patents

Description

  The present invention relates to a bending steel material manufacturing apparatus and manufacturing method by three-dimensional hot bending and quenching (3DQ), and specifically, even if there is a variation in warpage of the steel material, the desired material is desired. The present invention relates to a manufacturing apparatus and a manufacturing method of a bent steel material by three-dimensional hot bending quenching, which can mass-produce a bent steel material having dimensional accuracy (processing accuracy).

Patent Document 1, the quenching apparatus 1 bent between three-dimensional thermal outlined in Figure 7 A (hereinafter together even while bending hardening apparatus three-dimensional heat of Figure 7B to be described later is also referred to as "3DQ device", with these 3DQ device 3D hot bending quenching is abbreviated as “3DQ”).

  As shown in FIG. 7A, a positioning device (support roll) 3 in which a workpiece 2 (a steel pipe is taken as an example in the following description) that is a hollow steel material having a closed cross section is fixedly arranged at a predetermined position. While the positioning is performed, the feeding device 4 feeds the steel pipe 2 in the axial direction (the direction indicated by the arrow in FIG. 7A).

On the downstream side in the feed direction of the steel pipe 2 from the positioning device 3 (in this specification, simply referred to as “downstream side”, and the opposite positional relationship is also referred to as “upstream side”), the steel pipe 2 is heated from its surroundings. An annular high frequency induction heating coil 5 (hereinafter also simply referred to as “coil”) is disposed. High-frequency power is supplied to the coil 5 from a bus bar (feeder) 6 that suspends and supports the coil 5, and the steel pipe 2 to be fed is rapidly heated in a quenchable temperature range of Ac ₃ points or more in a short time (about 2 seconds). Cooling water is injected onto the outer peripheral surface of the heated steel pipe 2 from the annular water cooling device 7 disposed immediately downstream of the coil 5 to quench the steel pipe 2. Reference numeral 6-1 in FIG. 7A denotes a transformer that generates high-frequency power to be supplied to the coil 5 via the bus bar 6.

  The high temperature part (heated part) 2a formed in the steel pipe 2 after being heated by the coil 5 until being cooled by the water cooling device 7 is disposed downstream of the water cooling device 7 by the movable roller die 8-2. By bending or shearing the steel pipe 2 by controlling the position continuously or intermittently, the steel pipe 2 is hot worked to produce a bent steel material 9 that is quenched.

Hardening apparatus bent between three-dimensional heat of Figure 7A 1, since it is possible to tilt according to the shape of the member to produce a movable roller die 8-2 in the vertical direction as well as horizontally only to the feed direction of the steel pipe 2 A bending member in which the bending direction changes in one member can also be manufactured.

  FIG. 7B shows another three-dimensional hot bending quenching apparatus 0. The three-dimensional hot bending and quenching apparatus 0 of FIG. 7B grips the steel pipe 2 with the processing chuck 8-1 on the downstream side of the water cooling apparatus 7 and displaces the position of the processing chuck 8-1 to thereby change the coil 5 and the water cooling apparatus. The steel pipe 2 softened as a result of the local high temperature between 7 is bent and deformed. Since the processing chuck 8-1 can be displaced not only in a plane including the direction of feeding the steel pipe 2 to the heating device 5 such as left and right, but also in a space including the top and bottom, the magnitude and direction of bending in one member can be changed. Changing bending members can also be produced.

Figure 7A, machining chuck 8-1 or the movable roller die 8-2 also in the hardening device 1, 0 bending during any three-dimensional heat of FIG. 7B, the track advance input for example articulated defined by the machining program The bending steel material 9 having a desired shape is manufactured by the industrial robot 8-3 reproducing the track of the processing roller die or the processing chuck.

  In the case of mass production of the bent steel material 9 by the 3DQ apparatus 1, until now, the industrial robot is operated with respect to all the steel pipes 2 by the same machining program, and the track of the machining chuck 8-1 or the movable roller die 8-2 is moved. The steel pipe 2 was regenerated and subjected to three-dimensional hot bending quenching. Thereby, the high dimensional accuracy (processing accuracy) requested | required of the bending steel material 9 used as a raw material of the structural member of a motor vehicle, for example was able to be ensured enough.

International Publication No. 2006/093006 Pamphlet

  However, as a result of intensive studies by the present inventors, the steel pipe 2 which is a processed material in the 3DQ apparatus 1 is, for example, a long-shaped rectangular steel pipe with a rectangular cross-section manufactured by roll forming a steel pipe with a circular cross-section ( For example, a short deformed steel pipe cut out from a total length of 7 m (for example, a total length of 2 m) is bent by mass production by the 3DQ apparatus 1 according to the length of the long deformed steel pipe or the cutting position from the long deformed steel pipe. It has been found that the dimensional accuracy (processing accuracy) of the steel material 9 is lowered.

  When the bent steel material 9 is used as a material for parts (for example, various pillars, undercarriage parts, seat parts, door impact beams) that require a particularly severe dimensional tolerance, such as an allowable tolerance of ± 0.5 mm, among automobile parts. However, this tolerance cannot be satisfied, resulting in a decrease in productivity and yield, and an increase in manufacturing cost.

  That is, when the allowable tolerance is not comparatively strict, it is possible to mass-produce the bent steel material 9 having the allowable tolerance without any problem. However, the steel pipe 2 is formed by, for example, rolling a steel pipe having a circular cross section. It is known before the filing of the present application that the tolerance is not satisfied in the case of a short deformed steel pipe (for example, 2 m in total length) cut out from a long deformed steel pipe having a rectangular cross section to be manufactured (for example, a total length of 7 m). It turned out that there was a new problem that was not. Therefore, as a matter of course, Patent Document 1 does not disclose or suggest this new problem or its solution.

  The present invention has been made in view of the new problems of the prior art, and it is possible to stably produce a bent steel material that satisfies a particularly severe dimensional tolerance such as an allowable tolerance of ± 0.5 mm by 3DQ using a deformed steel pipe as a raw material. It is an object of the present invention to provide a manufacturing apparatus and a manufacturing method of a bent steel material that can be mass-produced. In other words, an object of the present invention is to provide a manufacturing apparatus and a manufacturing method of a bent steel material that can accommodate an allowable tolerance of, for example, ± 0.5 mm in a bent steel material mass-produced by a 3DQ apparatus.

  As a result of intensive studies in order to solve the above problems, the present inventors have obtained knowledge A to D listed below.

  (A) A long-shaped deformed steel pipe having a rectangular cross section (for example, a total length of 7 m), which is a material of the steel pipe 2, is manufactured through a forming line that rolls a long steel pipe having a circular cross section into a predetermined rectangular cross section. However, a large number of forming rolls constituting this forming line are arranged side by side with a predetermined interval in the longitudinal direction of the material. For this reason, in this forming line, the tip portion of the long steel pipe having a circular cross section is formed without being constrained by the forming roll, so that a minute warp inevitably occurs in the tip portion. On the other hand, in a long steel pipe having a circular cross section, such a warp hardly occurs in a portion following a tip portion (a portion in which a warp occurs in a steel pipe having a rectangular cross section). Hereinafter, this warping will be described in detail based on the results of a trial test conducted by the present inventors.

Figure 8A is an explanatory view showing a cut-out status of the Material of 3DQ in prototype tests conducted by the present inventors.

The present inventors, as shown in FIG. 8A, obtained by performing roll forming the steel pipe elongated circular cross-section, vertical 42mm, the lateral 36mm in total length 7m of rectangular cross section elongated profiled steel tube, TOP member positioned on the distal end side of the steel tube (during roll forming of length 2280mm obtained by further 3 divided after 100mm cut tip side at the time of roll forming, MID material and roles molding located in the center at the time of roll forming using BTM material) located on the rear end side of the case as a material for 3DQ, prototype testing a-pillar is an automobile parts, TOP member of a number of profiled steel, was performed on each of the MID substrate contact and BTM material .

  The overall shape and cross-sectional shape of the A pillar are shown in FIG. 8B. The prototype A-pillar is placed on a platform called figure-viewer with a shim sandwiched, and its dimensional accuracy (processing accuracy) is evaluated. When the A-pillar is molded in the regular shape as designed, the gap between the figure and the A-pillar is the thickness of the shim at any measurement point.

  The numbers in FIG. 8B indicate the measurement points in the longitudinal direction of the A pillar, and the symbols A and B in the cross-sectional view in FIG. 8B indicate the measurement points in the A pillar cross section. The dimensional accuracy (machining accuracy) of the A pillar is evaluated from the difference between the appearance at each measurement location, the size of the gap between the A pillars, and the thickness of the shim. That is, as shown in the overall view of FIG. 8B, 17 measurement positions (cross-sections) are set at equal intervals in the longitudinal direction of the A pillar, and the gap with the appearance is measured at the ridgeline R stop portion to reduce the thickness of the shim. Was obtained as a difference in normal dimensions. In this measurement, two points (A, B) in the cross-sectional direction Y-plane and Z-plane are measured at the measurement positions 1, 4, 7, 10, 13, 16 in the longitudinal direction, and one point ( Only A) was measured.

  FIG. 9A is a graph showing an error from the normal shape in the Y plane of FIG. 8B of the TOP material, the MID material, and the BTM material. The measurement position in FIG. 9A indicates the measurement position defined from the numbers in the additional figure (side surface) and A or B in FIG. 8B. FIG. 9B is also a graph showing an error from the normal shape in the Z plane of FIG. 8B of the TOP material, the MID material, and the BTM material. The difference from the exact size indicates the amount of displacement deviating from the normal shape. When the measurement position of the A pillar is displaced outside the cross section of the A pillar, it is evaluated as positive, and when it is inside, it is evaluated as negative.

  At this time, as shown in the graphs of FIGS. 9A and 9B, no matter how severely the accuracy correction of the trajectory of the industrial robot that supports the machining chuck 8-1 or the movable roller die 8-2 is performed. In addition, the dimensional accuracy (machining accuracy) of the Z plane of the obtained A pillar varies by about 0.3 mm, and the tendency is roughly classified into three types, and one type greatly changes to the positive side, while the remaining 2 The kind did not make much difference.

  The present inventors considered that these three types correspond to the cut-out position from a steel pipe having a length of 2280 mm, that is, TOP material, MID material, and BTM material. It was found that the accuracy of the A-pillar to be inferior to that of the A-pillar made of MID material or BTM material.

As described above, deformed steel tube is obtained by performing roll forming the steel pipe elongated circular cross-section, when from such a circular cross section of the roll forming into rectangular cross-section, the distal end side at the time of roll forming to be speak molded in a cantilever state due to the presence of sites that are not bound by the forming roll in, on the front end side when roll forming profiled steel tube that warpage occurs, is known. For this reason, the present inventors measured the change of the displacement amount of the side surface of the steel pipe in the longitudinal direction for each of the TOP material, the MID material, and the BTM material.

  10A to 10D show the displacements of the TOP-shaped material, the MID material, and the BTM material of the deformed steel pipe, which is the material of the A pillar, on the Y-surface front end side, Y-surface rear end side, Z-surface front end side, and Z-surface rear end side It is a graph which shows the measured value of. The front end side and the rear end side mean which was relatively on the front end side and the rear end side during roll forming. The displacement was measured based on the straight side of the deformed steel pipe.

  As can be understood from the graphs of FIGS. 10A to 10D, it can be seen that there is a steel pipe having a large amount of displacement on the tip end side of the Z plane. These steel pipes with large displacement were all TOP materials.

  Furthermore, the present inventors also measured the processing accuracy (difference from the normal shape) at each measurement location for the A pillar obtained using the TOP material as a raw material.

  FIG. 4 is a graph showing the distance and displacement from the tube end of the TOP material before three-dimensional hot bending and quenching, and FIG. 5 shows the processing accuracy at each measurement location of the TOP material after three-dimensional hot bending and quenching. It is a graph which shows.

  As shown in the graphs of FIGS. 4 and 5, there is some variation in the amount of displacement from the pipe end of the TOP material and the processing accuracy at each measurement location of the bent steel material made of the TOP material.

  In order to measure the amount of displacement, the present inventor cuts at the tip side 400 mm at the time of roll forming in an A-pillar made of TOP material (this position is a straight portion not subjected to quenching or bending). The amount of displacement in the longitudinal direction was measured based on the position of 400 mm on the tip side.

  When the steel pipe 2 has a displacement amount like the TOP material shown in FIG. 10C, the bent steel material 9 cannot satisfy the allowable tolerance. That is, the reason why the bent steel material 9 manufactured by the 3DQ apparatus 1 cannot satisfy the allowable tolerance is that a large displacement exists in the steel pipe 2. This displacement causes a slight elastic deformation when the material steel pipe is gripped by the processing chuck, and stress release occurs when heating, and the clearance between the heating coil and cooling nozzle and the material steel pipe fluctuates, resulting in straightness. Since the raw steel pipe without displacement such as the part and the timing of heating and cooling are slightly shifted, it is assumed that the shape becomes different from the case of machining the steel pipe without displacement and the machining accuracy is inferior.

  (B) Therefore, the amount of displacement existing in the steel pipe 2 is quantitatively grasped, and a machining program for regenerating the trajectory of the machining chuck 8-1 or the movable roller die 8-2 by operating the industrial robot is displaced. By changing according to the above, it becomes possible to set the tolerance of the bent steel material mass-produced by the 3DQ apparatus 1 within ± 0.5 mm, for example.

  That is, based on the result of the above-described trial test, the industrial robot is operated to change the trajectory of the machining chuck 8-1 or the movable roller die 8-2 for each of the TOP material, the MID material, and the BTM material (according to the displacement amount). It can be seen that the machining accuracy of the A pillar can be greatly improved. When the same track is used for the TOP material, the MID material, and the BTM material as in the prior art, the maximum variation is about 0.8 mm, whereas the track is changed to the TOP material, MID. By making the material and the BTM material different, the variation width can be halved to about 0.4 mm.

  (C) In the present invention, for the sake of simplicity, the displacement that changes in the longitudinal direction of the steel pipe is replaced with the warpage amount δ, and the trajectory of the machining chuck 8-1 or the movable roller die 8-2 is corrected according to the warpage amount δ. Also good. FIG. 11 is an explanatory diagram showing the definition of the warpage amount δ in the steel pipe 2.

  As shown in FIG. 11, in the present invention, the amount of warping δ is a steel pipe 2 having a straight part 2c and a part (warping part) 2d displaced from the straight part from one end 2a toward the other end 2b. On the other hand, it is defined as the fluctuation range of displacement in the warped portion 2d. When the longitudinal direction of the steel pipe 2 is the X axis, the warpage amount δ of the steel pipe 2 can be defined in any of the Y direction (Y surface warpage amount) and the Z direction (Z surface warpage amount). . In the present invention, the case where the slope (first derivative) at the tube end of the displacement amount graph from which noise is removed in FIG. 4 is positive is defined as a positive warp.

  FIG. 12 is a graph showing the relationship between the machining accuracy and the warpage amount δ in the vicinity of the center in the longitudinal direction where the variation is greatest (measurement position 8 in FIG. 8B).

  As shown in the graph of FIG. 12, it can be seen that as the warpage amount δ is larger, the measured value of the machining accuracy is shifted to the positive side.

  (D) As described above, the displacement amount or warpage amount δ of the steel pipe 2 before being processed by the 3DQ apparatus 1 is quantitatively measured, and the machining chuck 8-1 is added with the displacement amount or warpage amount δ taken into account. Or the above-mentioned subject can be solved by processing this steel pipe 2 after correcting (correcting) and setting up the track of movable roller die 8-2.

The present inventors have further studied based on these findings AD to complete the present invention.
The present invention positions a hollow and long steel material having a closed polygonal cross section and having a straight portion and a bent warped portion from one end portion toward the other end portion in the longitudinal direction. A positioning device for moving, a heating device (for example, a high-frequency induction heating coil) that is disposed at a first position apart from the steel material to be sent and that heats the steel material (to a quenchable temperature range when quenching); A cooling device that is disposed at a second position downstream of the first position in the steel feed direction and cools the steel material by spraying a cooling medium on the outer peripheral surface of the steel material, and the steel material from the second position. In the third position downstream of the feed direction of the steel, the portion heated and moved together with the positioning device is bent not only in the plane including the feed direction of the steel material in the first position but also in the space. By a processing device that processes steel material by deforming or shearing deformation, a warpage detection device that detects the warpage amount (displacement amount or warpage amount δ) of the steel material before being positioned by the positioning device, and the warpage detection device It is a manufacturing apparatus of a bending steel material provided with a control device which controls hot processing to the steel material by the processing device based on a detected value.

  From another point of view, the present invention provides a positioning device for a hollow and long steel material having a closed polygonal cross section and having a straight portion and a bent warped portion from one end portion to the other end portion. With a heating device (for example, a high frequency induction heating coil) arranged at a first position separated from the steel material to be fed while being moved in the longitudinal direction while positioning, the steel material is brought into a quenchable temperature range when quenching. ) The steel material is heated by blowing the cooling medium to the outer peripheral surface of the steel material from the cooling medium injection hole provided in the cooling device disposed at the second position downstream of the first position in the feed direction of the steel material. And is movably disposed not only in a plane including the steel material feed direction at the first position but also in a space at a third position downstream of the second position in the steel material feed direction. When a bending member is manufactured by performing hot working on a steel material by bending or shearing a portion heated together with the positioning device by a processing device to be warped, the steel material is warped before being positioned by the positioning device. A method for producing a bent steel material, characterized by controlling hot working on a steel material based on a detected value of a quantity (a displacement amount or a warpage amount δ).

  In the present invention, the steel material may be a polygonal cross-section steel pipe cut out from a polygonal cross-section steel pipe obtained by roll forming a circular cross-section steel pipe.

  According to the present invention, it is possible to stably mass-produce a bent steel material satisfying a particularly severe dimensional tolerance such as an allowable tolerance of ± 0.5 mm by 3DQ. That is, the allowable tolerance of the bent steel material mass-produced by the 3DQ apparatus can be set within ± 0.5 mm, for example. As described above, according to the present invention, even when the dimensional accuracy of the material before being processed by the 3DQ device is lowered, the variation in the processing accuracy of the bent steel material manufactured by the 3DQ device is practically used. It is possible to remarkably suppress the production of a bent steel material out of tolerance with a stable reduction to an extent that there is no problem.

FIG. 1 is an explanatory view showing an apparatus for manufacturing a bent steel material according to the present invention. FIG. 2 is an explanatory diagram showing a situation where three steel pipes having a polygonal cross section (for example, a total length of 2 m) are cut out from a long steel pipe having a square cross section. FIG. 3 is a graph showing the results of measuring the difference between the bent steel material and the normal shape. FIG. 4 is a graph showing the results of measuring the displacement amount of the steel pipe (tip member). FIG. 5 is a graph showing the results of measuring the processing accuracy after 3DQ processing of a steel pipe (tip member). FIG. 6 is a graph showing an example of a flowchart of robot trajectory selection. FIG. 7A is an explanatory diagram showing a 3DQ device disclosed in Patent Document 1. FIG. FIG. 7B is an explanatory diagram showing another 3DQ device. FIG. 8A is an explanatory diagram showing a 3DQ material cut-out state in a prototype test conducted by the present inventors. FIG. 8B is an explanatory diagram showing an overall shape and a cross-sectional shape of the A pillar. FIG. 9A is a graph showing an error from the normal shape on the Y surface (side surface) of the TOP material, the MID material, and the BTM material, and FIG. 9B is a Z diagram of the TOP material, the MID material, and the BTM material. It is a graph which shows the error from the regular shape in a field (longitudinal surface). FIG. 10A is a graph showing measured values of the displacement amount at the tip end side of the Y surface of each of the TOP material, the MID material, and the BTM material. FIG. 10B is a graph showing measured values of the displacement amount on the rear end side of the Y surface of each of the TOP material, the MID material, and the BTM material. FIG. 10C is a graph showing measured values of the displacement amount at the tip end side of the Z surface of each of the TOP material, the MID material, and the BTM material. FIG. 10D is a graph showing measured values of displacement amounts on the Z-plane rear end side of the TOP material, the MID material, and the BTM material. FIG. 11 is an explanatory view showing the definition of the warpage amount δ in the steel pipe. FIG. 12 is a graph showing the relationship between the warpage amount δ and the machining accuracy in the vicinity of the center in the longitudinal direction where the variation is greatest.

The present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is an explanatory view showing an apparatus 10 for producing a bent steel material 9 according to the present invention. In the following description, the same components as those of the manufacturing apparatus 1 shown in FIG. 7A or FIG. 7B described above are denoted by the same reference numerals, and redundant description is omitted.

  As shown in FIG. 1, the manufacturing apparatus 10 includes a positioning device 3, a high frequency induction heating coil 5, a cooling device 7, a processing device 8, a warpage detection device 11, and a control device 12.

[Positioning device 3]
In the following description, the case where the steel material, which is the processed material in the present invention, is a hollow and long steel pipe 2 having a closed polygonal (quadrangle) cross section.

  A long steel pipe 2-1 having a square cross section (for example, a total length of 7 m), which is a material of the steel pipe 2, has a large number of forming rolls arranged with a long cross section of a circular cross section at a predetermined interval. It is roll-formed through a forming line provided and formed into a predetermined rectangular cross section. For this reason, since the front end portion of the long steel pipe having a circular cross section in this forming line is formed without hitting the forming roll, warping is inevitably generated in the front end portion. The steel pipe 2 is cut out from the long deformed steel pipe 2-1 having a rectangular cross section and is provided as a short steel pipe 2-2 having a polygonal cross section (for example, a total length of 2 m).

  Since the steel pipe 2 is manufactured through such a manufacturing process, the mass-produced steel pipe 2 includes a straight portion 2c from one end 2a to the other end 2b as illustrated in FIG. Some have a warped portion 2d extending from the straight portion 2c.

  The positioning device 3 is a device for moving the steel pipe 2 in the longitudinal direction while positioning the steel pipe 2 at a predetermined position. For example, as shown in FIG. 1, the positioning device 3 has a shape that comes into contact with the outer peripheral surface of the steel pipe 2. It comprises two pairs of perforated rolls (3a, 3a) having an inner surface.

  The steel pipe 2 is fed in the longitudinal direction by a feed mechanism 4 such as a ball screw. It is desirable that the feed mechanism 4 has a rotation prevention function or a rotation control function so that the steel pipe 2 does not freely rotate around the axis due to the movement of the machining chuck 8-1.

[Heating device (high frequency induction heating coil 5)]
The heating device (for example, the high frequency induction heating coil 5) is disposed at a first position at a predetermined distance from the outer peripheral surface of the steel pipe 2 sent by the positioning device 3. The high-frequency induction heating coil 5 has a substantially rectangular annular outer shape that can surround the steel pipe 2 away from the outer peripheral surface of the steel pipe 2, and the steel pipe 2 (in the case of quenching, a quenchable temperature range (Ac ₃ points) To the above)).

The high-frequency induction heating coil 5 is suspended and supported by a bus bar (feeder) 6 to which high-frequency power generated by the transformer 6-1 is supplied. The high-frequency power is supplied by the bus bar (feeder) 6 to the steel pipe 2. (When quenching, heat to a quenchable temperature range (Ac ₃ points or more)).

[Cooling device 7]
The cooling device 7 is arrange | positioned in the 2nd position of the downstream of the feed direction of the steel pipe 2 rather than the 1st position where the high frequency induction heating coil 5 is installed. The cooling device 7 injects a cooling medium (cooling water is taken as an example in the following description) toward each of four sides forming the outer surface of the steel pipe 2 in the cross section of the steel pipe 2.

  The cooling device 7 can also quench the steel pipe 2 by injecting cooling water to each side of the steel pipe 2 to form a steel structure composed of martensite or martensite and tempered martensite.

[Processing device 8]
The processing device 8 is disposed at a third position downstream of the second position in the feed direction of the steel pipe 2 so as to be movable not only in a plane including the feed direction of the steel pipe 2 at the first position but also in a space. Thus, the steel pipe 2 is hot-worked by bending or shearing the heated portion 2a of the steel pipe 2 together with the positioning device 3. Thereby, the amount and direction of bending of the steel pipe 2 can be changed arbitrarily.

  As the processing device 8, either the processing chuck 8-1 or the movable roller die 8-2 can be used. The processing chuck 8-1 grips the steel pipe 2 at or near the tip of the steel pipe 2. On the other hand, the operating roller die 8-2 is disposed downstream of the water cooling device 7. Both the machining chuck 8-1 and the movable roller die 8-2 are controlled to be displaced not only in a plane including the feed direction of the steel pipe 2 at the first position but also in space, so that the steel pipe 2 is bent or deformed. The steel pipe 2 can be subjected to hot working to produce a bent steel material 9 that has been quenched.

Machining chuck 8-1 or the movable roller die 8-2 is supported by the track previously inputted for example articulated industrial robots 8 -3 defined by the machining program, the industrial robot is play this track By doing so, the bent steel material 9 which has a desired shape is manufactured.

[Warpage detection device 11]
The warp detection device 11 detects the amount of displacement from the straight portion of the steel pipe 2 in the warped portion of the steel pipe 2 before being set in the manufacturing apparatus 10, that is, the steel pipe 2 before being positioned by the moving positioning device 3.

  As the warp detection device 11, a conventional device as this type of detection device may be used. For example, a laser displacement meter can be used to accurately measure the displacement, and a measurement gauge can be used simply. . When more machining accuracy is required, the correlation between the displacement and accuracy may be checked for each part to be manufactured, and the interpolated robot trajectory data may be created and machined each time.

[Control device 12]
The control device 12 controls hot working on the steel pipe 2 by the processing device 8 based on the detection value of the displacement amount by the warp detection device 11. That is, the control device 12 quantitatively grasps the degree of warpage existing in the steel pipe 2 based on the detected value of the displacement amount by the warpage detection device 11, and operates the industrial robot to move the machining chuck 8-1 or move. A machining program for reproducing the trajectory of the roller die 8-2 is corrected and set according to the degree of warpage, and the industrial robot is operated based on the machining program set by changing the machining chuck 8-1 or The trajectory of the movable roller die 8-2 is regenerated. Thereby, it becomes possible to set the tolerance of the bent steel material mass-produced by the 3DQ apparatus 1 within ± 0.5 mm, for example. Further, as a simple method, the trajectory of the machining chuck 8-1 or the movable roller die 8-2 may be corrected based on the displacement fluctuation range (warpage amount δ).

  FIG. 2 is an explanatory diagram showing a situation in which three steel pipes 2-2 having a polygonal cross section (for example, a total length of 2 m) are cut out from a long steel pipe 2-1 having a square cross section.

  As shown in FIG. 2, three steel pipes 2-2 are cut out from the steel pipe 2-1, as a front end member, an intermediate member, and a rear end member. Three steel pipes P-1 (front end member), P-1 (intermediate member), P-1 (rear end member) cut out from one steel pipe 2-1, and 3 cut out from another steel pipe 2-1. About the steel pipe P-2 (front end member), P-2 (intermediate member), P-2 (rear end member), it is marked by which part of the steel pipe 2-1 is cut out, and is hot by the 3DQ device 1 The bending steel material 9 was manufactured by processing. And the difference with a regular shape was measured about the obtained bending steel material 9. FIG. The measurement results are shown graphically in FIG.

  As shown in the graph of FIG. 3, the processing accuracy when the tip member is processed is clearly unsatisfactory when the intermediate member or the rear end member is processed.

  Moreover, when the curvature (displacement amount from a straight part) of the steel pipe 2-2 was measured, a curvature exists only in a tip member.

  Furthermore, warpage and processing accuracy after 3DQ processing were measured for three steel pipes 2-2 (tip members) cut out from the three steel pipes 2-1. The results are shown in the graphs of FIGS.

  As shown in the graphs of FIGS. 4 and 5, it has been found that the dimensional accuracy (processing accuracy) after 3DQ processing differs depending on the amount of displacement in comparison between the tip members.

  When measuring accuracy after processing, both ends of the processed bent steel material are supported, so that the accuracy of the center part goes out to the positive side. Means that

  From the above results, it is possible to improve the processing accuracy of the bent steel material 9 after 3DQ processing by determining the presence / absence and size of the warp of the steel pipe 2 before 3DQ processing and correcting and setting the processing program accordingly. You can see that

  Table 1 collectively shows an example of changes in the machining program for the present invention example in which the machining program is changed according to the cutting position from the steel pipe 2-1, and the comparative example in which the machining program is not changed.

  For example, from the graph of FIG. 12, when the amount of warpage δ of the Z plane of the steel pipe 2 is 0.75 mm, the accuracy measurement value in the vicinity of the center in the longitudinal direction with the largest variation is predicted to be about +0.25 mm. A robot trajectory capable of correcting +0.25 mm in the reverse direction may be created and used.

  Conversely, the robot trajectory may be created by using the steel pipe C in FIG. In this case, if the steel pipe 1 is used, the accuracy measurement value is expected to be −0.25 mm, so that correction of +0.25 mm is applied.

FIG. 6 is a graph showing an example of a flowchart of robot trajectory selection.
As shown in FIG. 6, a robot trajectory corresponding to the warp (displacement amount) of the steel pipe 2 is created in advance before the start. At this time, when the steel pipe 2 has a positive warp, the robot trajectory is corrected so as to reduce the machining amount as compared with the trajectory for the steel pipe without the warp. The larger the displacement amount, the larger the correction amount.

  In S1, the warp direction of the steel pipe 2 with respect to the bending direction is determined. If the warp is negative, the process proceeds to S2. If there is no warp, the process proceeds to S3. If the warp is positive, the process proceeds to S4.

  In S2, processing is performed with a robot trajectory for negative warped steel pipe (a correction amount is added to the reference bending amount), and in S3, processing is performed with a robot trajectory for warping-free steel pipe (reference bending amount). Machine with a robot trajectory for the positive warped steel pipe (subtract the correction amount from the standard bending amount). In this way, the processing is finished.

Thus, warpage of the steel pipe before being performed processing in 3DQ device 1 0 (displacement amount) leave quantitatively measured, in consideration of the amount of displacement of the machining chuck 8-1 or the movable roller die 8-2 By processing the steel pipe after correcting and setting the trajectory, it is possible to stably mass-produce a bent steel material satisfying a particularly severe dimensional tolerance such as an allowable tolerance of ± 0.5 mm by 3DQ.

  According to the present invention, even when the dimensional accuracy of the steel pipe 2 before being processed by the 3DQ device 10 is lowered, the dimensional accuracy (processing accuracy) of the bent steel material 9 manufactured by the 3DQ device 10 is improved. The variation can be stably reduced to an extent that does not cause a problem in practice, and the production of the bent steel material 9 having a deviation from the tolerance can be greatly reduced.

  Since the dimensional accuracy (processing accuracy) of the bent steel material 9 manufactured according to the present invention is improved, it is easy to assemble in the subsequent process, and it is possible to suppress a decrease in yield due to deviation of accuracy tolerance, and to improve productivity and Cost reduction is possible.

  In addition, the dimensional accuracy (machining accuracy) variation of the mass-produced bent steel material 9 as a whole is greatly improved, so parts with severe tolerances (for example, various pillars, undercarriage parts, seat parts, door impacts) The bent steel material 9 can be applied to the beam.

DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus 2 Steel pipe 2a High temperature part 3 Movement positioning apparatus 5 High frequency induction heating coil 7 Cooling apparatus 8 Processing apparatus 8-1 Processing chuck 8-2 Movable roller die 8-3 Articulated industrial robot 9 Bending member 10 Manufacturing apparatus 11 Warpage detection device 12 Control device

Claims (2)

  For positioning a hollow and long steel material having a closed polygonal cross section and having a straight portion and a bent warped portion from one end portion to the other end portion while moving in the longitudinal direction. A positioning device, a heating device that is disposed at a first position apart from the steel material to be fed, and that heats the steel material, and a second position downstream of the first position in the feeding direction of the steel material And a cooling device that cools the steel material by spraying a cooling medium on the outer peripheral surface of the steel material, and a third position downstream of the second position in the feed direction of the steel material at the first position. The steel material is arranged so as to be movable not only in a plane including the feeding direction of the steel material but also in a space, and bending or shearing a portion heated together with the positioning device. A processing device that performs processing, a warpage detection device that detects a warpage amount of the steel material before being positioned by the positioning device, and hot processing of the steel material by the processing device based on a detection value by the warpage detection device An apparatus for producing a bent steel material, comprising:   A hollow and long steel material having a closed polygonal cross section and having a straight part and a curved warped part from one end to the other end is moved in the longitudinal direction while being positioned by a positioning device. While heating, the steel material is heated by the heating device arranged at the first position separated from the steel material to be sent, and at the second position downstream of the first material in the feeding direction of the steel material. The steel material is cooled by spraying a cooling medium on the outer peripheral surface of the steel material from a cooling medium injection hole provided in the cooling device, and a third position downstream in the feed direction of the steel material from the second position. In the first position is heated together with the positioning device by a processing device that is movably disposed not only in a plane including the feeding direction of the steel material but also in a space. Based on the detected value of the amount of warpage of the steel material before being positioned by the positioning device when producing a bending member by performing hot working on the steel material by bending or shearing the part, A method for producing a bent steel material, characterized by controlling hot working on the steel material.