Vehicle reinforcement beam roll-formed from metal thin plate

0001The present invention relates to a bumper reinforcement beam that is tubular and has one (single) central support leg and is used in vehicle bumper systems. The present invention also relates to a roll forming apparatus and a method of forming the beam. However, the present invention is not intended to be limited only to bumper reinforcement beams for vehicles.

0002This application provides the benefits under 35 USC 119 (e) in US Patent Provisional Application No. 61 / 385,680, filed September 23, 2010, entitled "TUBULAR BEAM WITH SINGLE CENTER LEG". Insist. The entire contents of this application are incorporated herein by reference.

0003Modern vehicle bumper systems typically include a reinforcement beam, which is designed for strength and impact characteristics to meet government and insurance industry standards for a particular vehicle. To minimize the overall weight of the vehicle, maximize the strength-to-weight ratio, fit within the limited vehicle packaging space, and meet the vehicle's aesthetic and functional requirements at the vehicle front and rear ends. It is designed. At the same time, the processing and methods of producing the beam minimize undesired product dimensional variations and product quality variations, while also minimizing manufacturing costs, optimizing manufacturability, and minimizing scrap metal. It is preferable to limit it. Roll forming processes and methods have been found to be particularly effective in the mass continuous production of bumper reinforcement beams with competitive price and high dimensional consistency. However, the industry is very competitive, so even the slightest improvement can be important.

0004Moreover, many of the above desired features are contradictory, so how to improve a particular bumper reinforcement beam and how to improve the roll forming process to make that beam. It's not clear. For example, a heavier beam may be stronger, but will result in an unacceptable increase in vehicle weight. High-strength materials, which may be preferred, are expensive, difficult to mold, and cause high wear on machine tool equipment. Precise control over the positioning of the edges of the sheet during roll forming facilitates accurate cross-sectional shape of the beam, reduces excess material along the edges and minimizes beam weight. It is desirable to reduce tolerances along the edges so that they can be made and to facilitate consistent contact during welding. However, this may require additional machine tool equipment control, hardware control and software control in addition to the extra roll forming process and roll forming station, each of which increases capital investment. This makes the roll forming process more complicated. The above beam includes two lamellar edges formed in contact with other lamellar materials, where each edge is welded by a welder to permanently form the tubular shape of the beam. ing. However, welders, especially when the welder is located at various stations along the overall length of the roll forming apparatus, occupy space along the roll forming apparatus and therefore significantly increase the floor space requirement. In addition, capital investment will be increased. However, welding on the two opposite sides of the beam is difficult due to the presence of scattered debris that adversely affects one or both welders. In particular, the weld must be consistent and reliable in order to provide reliable and consistent impact strength in the bumper reinforcement beam and associated bumper systems.

0005In one aspect of the invention, the reinforcement beam is formed from a single thin plate and shares a common wall and is coplanar with the front wall and aligned coplanar. A beam containing a first tubular portion and a second tubular portion having a rear wall portion in the front wall portion, each front wall portion containing a channel rib in the thin plate, and a first rounded portion. And the first edge with the first tip, the second rounded part and the second edge with the second tip, and one of the aligned front walls is common. A third rounded portion that connects to one end of the wall and a fourth rounded portion that connects one of the rear walls to the other end of the common wall. The first rounded portion and the third rounded portion are both welded at the first weld and have a cavity depth of at least twice the thickness of the lamella, including the front fissure rib. The (crevice rib) is formed and the second rounded part and the fourth rounded part are welded together at the second weld and have a cavity depth of at least twice the thickness of the sheet. The rear crevices with the channel ribs and the anterior crevice ribs form ribs that reinforce the front surface of the beam.

0006In another aspect of the present invention, the thin plate is formed into a beam having a common central support leg extending between four outer wall portions and two opposite outer wall portions of the outer wall portion. The four outer wall portions define a rectangular cross section, the central support leg portion divides the cross section into an adjacent first tubular portion and a second tubular portion, and the central support leg portion is the central support leg portion. An apparatus is provided in which each has a rounded end that defines a sliding surface perpendicular to the relative, and the lamella has an edge that abuts the rounded end. The device comprises a roll forming machine including a roll forming station with rollers for forming the lamella into a beam with four outer walls and a common central support leg, the roll forming machine is a welder and a box. Including a welding station with a mold welding jig, the box welding jig includes a jig frame and an external mandrel supported by the jig frame and supporting the four outer walls in the desired exact shape. Two of the external mandrels are movable and opposed, and two so as to move the opposing external mandrel to engage the related and opposing outer walls of the four outer walls. Includes at least one actuator operably connected to an opposing external mandrel. The device further comprises an internal mandrel within each of the adjacent first and second tubular portions, the internal mandrel being an upstream fixed line to remain generally adjacent to the external mandrel. Supported by. With this configuration, the internal and external mandrel, in combination with the urging of the spring and the opposite urging of the two opposing external mandrel, controls the shape of the beam by the deflection and movement of the sheet material along the sliding surface. This actively maintains the correct shape during the welding process of the welder when in a box-shaped welding jig.

0007In a narrower aspect, the internal mandrels each include an opposing semifield and a spring that urges the opposing semifields to separate from each other against the external mandrel and against the force of the actuator.

0008In another aspect of the present invention, the thin plate is formed into a beam having a common central support leg extending between four outer wall portions and two opposite outer wall portions of the outer wall portion. The four outer wall portions define a rectangular cross section, the central support leg portion divides the cross section into an adjacent first tubular portion and a second tubular portion, and the central support leg portion is the central support leg portion. An apparatus is provided in which each has a rounded end that defines a sliding surface perpendicular to the relative, and the lamella has an edge that abuts the rounded end. The device comprises a roll forming machine including a roll forming station with rollers for forming the lamella into a beam with four outer walls and a common central support leg, the roll forming machine is a welding machine and a box. Including a welding station with a mold welding jig, the box welding jig includes a jig frame and an external mandrel supported by the jig frame and supporting the four outer walls in the desired exact shape. Two of the external mandrels are movable and opposed, and two so as to move the opposing external mandrel to engage the related and opposing outer walls of the four outer walls. Includes at least one actuator operably connected to the opposing external mandrel, the other two external mandrel of the external mandrel being between two opposing outer walls with a central support leg extending in between. It is fixed and opposed so that the distance is largely fixed. With this configuration, the external mandrel, in combination with the urging of two opposing external mandrels, controls the shape of the beam by bending and moving the material of the sheet along the sliding surface, thereby in the box welding jig. At one point, the correct shape is actively maintained during the welding process of the welder.

0009In another aspect of the invention, the apparatus comprises a roll forming machine comprising a roll forming station having rollers for forming a lamella into a continuous beam having four outer walls and a common central support leg. The roll forming machine includes a welding machine and a welding station having a box-shaped welding jig, and the welding machine generates a laser beam with an upward angle for welding a continuous beam to permanently fix the cross section. And located under a continuous beam upstream or downstream from the box welder, thereby allowing the laser beam to abut on one of the rounded ends of the rounded edge. Weld in the downward crevice formed by one of them. With this configuration, the welder welds the continuous beam from below the continuous beam, but is positioned to avoid falling debris.

0010In another aspect of the invention, the apparatus comprises a roll forming machine comprising a roll forming station having rollers for forming a lamella into a continuous beam having four outer walls and a common central support leg. The roll forming machine includes a one-piece welding station having a top side welding machine, a bottom side welding machine and a box-shaped welding jig, and the welding machine is a continuous beam upper position and lower position in the welding station. A continuous beam is welded so that the cross section is permanently fixed by welding at the same time. With this configuration, welding is performed at one welding station rather than at multiple welding stations.

0011In another aspect of the invention, the device comprises a roll molding machine that includes a first roll molding station. The first roll forming station has a set of first rollers for forming a central support leg made of a thin plate and an outer wing made of a thin plate, and the outer wing extends perpendicular to the central support leg. It has a portion adjacent to the central support leg that is present and joined to the central support leg by a rounded end, and the outer wing also has a rounded edge formed on the outer wing. Have. The roll forming machine further includes an additional roll forming station having an additional set of rollers for forming the outer wing portion into a first tubular portion and a second tubular portion, and the central support leg portion is a first tubular portion. It is a common wall portion that forms a part of each of the tubular portion and the second tubular portion. Roll forming machines include a top-side welding machine and a bottom-side welding machine that weld rounded edges to rounded ends.

0012Related methods also form part of the present invention.

0013These aspects, purposes and features of the invention and other aspects, purposes and features will be understood and recognized by those skilled in the art by examining the following specification, claims and accompanying drawings.

0014<figref num="1">It is a top view of the bumper reinforcement beam which is tubular and includes one central support leg.</figref><figref num="2">It is sectional drawing along the line II-II of FIG.</figref><figref num="3">It is a figure of the roll forming apparatus for carrying out the roll forming process of this invention.</figref><figref num="4">It is a series of cross-sectional views showing the shape of the thin original plate in each molding process when molding the beam of FIG. 1 and labeled with S1 to S33.</figref><figref num="5">It is sectional drawing of the beam of FIG. 1 and FIG. 2 including the seam tracking disk which forms a part of a welding station.</figref><figref num="6">It is a figure of a deformed beam which is similar to FIG. 1 and FIG. 2 but has a modified cross section.</figref><figref num="7">It is a side view which shows the welding station near the end of a roll forming process.</figref><figref num="8">FIG. 7 is a cross-sectional view of the welding station of FIG. 7 showing a pressure box fixture for holding the final shape of a roll forming beam during a simultaneous double-weld process.</figref>

0015The bumper reinforcement beam 40 (Figure 1) is a tubular reinforcement beam 50 for the vehicle bumper system and a vehicle frame for use in the vehicle front bumper system (shown in Figure 1) or the rear bumper system. It is equipped with a mount 41 attached to the beam 50 for easy attachment to. The illustrated beam 50 has a longitudinal central section 42 bent at a first radius R1 and a longitudinal outer section bent at a narrower second radius R2 to fit the aerodynamic shape of a particular vehicle. Including with the end. However, the concept of the present invention is whether it is straight or sweep, and whether it is consistently bent / curved with one radius or various longitudinal bends ("curved"). ), It is considered that it can be used for any beam.

0016The beam 50 of the present invention is made of a thin steel plate material with a thickness of 0.8 mm to 1.4 mm and a tensile strength of about 800 MPa to 2000 MPa (ie about 120 ksi [kilopound force per square inch] to 290 ksi). The beam shown has a height of about 80 mm and a depth of about 40 mm (at the vehicle mounting position), with two channel ribs (one for each tubular) formed in front of the beam. It has become. Each channel rib shown is about 8 mm to 10 mm deep and about 8 mm to 10 mm wide and includes a rounded bottom. However, it is conceivable that the beams of the present invention can be made of a variety of materials, including AHSS (advanced high-strength steel), and the beams of the present invention are approximately 0.8 mm to 3.0 mm thick (or 0.8). It can be made from thin plates with a thickness of mm to 1.4 mm, etc., and can be made with various beam cross-sectional sizes such as a height of about 80 mm to 150 mm and a depth of about 30 mm to 60 mm. It is also conceivable that the lengths can be equal to or slightly greater than the distance between the vehicle mounts / between the tips of the bumper frame rails.

0017The beam 50 (FIG. 3) of the present invention is formed from a single metal steel plate on a roll forming apparatus via a series of paired rolls of a roll forming station, in which each station is formed in FIG. 4 Roll-formed flower in steps 1-33 in Perform a molding operation as indicated by pattern). During processing, one lamella is an adjacent tubular formed on either side of one central wall (sometimes referred to herein as a "single" wall or "central support leg"). It is molded to have a portion. The roll forming machine includes forming rolls of the first region in stations S1 to S7, in which stations S1 to S7 have a central section (that is, a central wall portion) and a thin plate outer section outward with respect to the central wall portion. Moreover, it includes forming in a state of extending in a substantially vertical direction. Radiated thin plate edges are also formed in steps S1-S7. The roll forming machine further forms the first tubular portion and the second tubular portion on each side portion of the central support leg portion, and shares the central support leg portion as a common wall portion at stations S8 to S33. Includes molding rolls in the second region. The channel ribs are substantially formed in steps S8-S12 and are useful for controlling the lateral position of the sheet as it traverses the roll forming apparatus. Laser welding is performed at or after station S33. Alternatively, welding can be performed in two separate steps, for example in a roll forming process in which the first tubular portion is formed in the middle of the process (well before the last forming station).

0018Specifically, as shown, the portion slightly less than the "half" of the thin plate is deformed in the first direction (shown clockwise in FIG. 4) to become the first tubular portion. At this time, the first rounded edge of the thin plate is in contact (and welded) with the rounded end of the central wall. The opposite "half" of the lamella is deformed in the opposite second direction (such as counterclockwise) into a second tubular, where the second rounded edge is The other rounded end of the central wall is in contact (and welded) to the given end. The line of contact for welding to the first rounded edge is at the end of the rounded portion where the end of the lamella is "flat". Similarly, the rounded end contact line of the central wall is at the end of the central wall where the central wall becomes "flat". However, it is desirable to have the rounded portion as the main contact so that the laser beam of the weld process has the optimum conditions for creating a consistent weld. In particular, in the welding process, the laser beam is abutting line formed by the rounded edges and the rounded edges. Includes contact) entering the crevice and heating the material. For this reason, the ends of the slab edges are formed so that they do not create gaps at the bottom of the crevice that will (and may) adversely affect welding depending on their size, regardless of machining variations. It is desirable to be done.

0019In particular, the box-type welding jig assists in setting the contact line contact portion and setting a desired contact pressure for the welding process at the contact line contact portion. The mating materials are held in contact with each other by the welding jig shown in FIG. 8 as described below, thereby facilitating good welding. The rounded shape of the edges allows for good contact, but nevertheless the edges bend, slide and bend, especially along the sliding surfaces P1 and P2 (box welding jigs). It allows (caused by the forces generated within the tool) to allow the jig to "set" and maintain the desired cross-sectional shape at the welding station. This configuration facilitates good welding and may reduce the importance of perfect dimensions of the edges. At the same time, the edge of the lamella contains a tip section of material inside the beam that extends away from the welding line. As mentioned above, the free end of the tip section is necessary to ensure that there is sufficient material for welding regardless of material changes and machining changes along the edges. However, excess material at the free end of the tip section results in additional weight to the waste and bumper beam. By precisely controlling the contact and engagement of the edges and abutting material, the length of the "free end" can be minimized and therefore the overall weight of the beam can be minimized. .. It turns out that even a few ounces of reduced weight can be important for automotive engineers and vehicle designers. The "free end" shown is assumed to be less than about 4 mm, but it may be possible to reduce it to 2 mm etc. in some cases, depending on the specific process parameters and functional requirements of the beam. ..

0020As mentioned above, the rounded edges of the lamellae are advantageously extended until they contact the rounded (bent) combined corners on the central support leg of the beam. It is present and welded to its corners, facilitating and enabling consistent and forgiving abuttal engagement. The two rounded parts at the edges and the two rounded parts at the ends of the central support legs allow the two sections of material to engage securely in line contact and with abutting force within the desired range. And therefore adapts better to dimensional variations during the manufacturing process. This configuration promotes good line contact of the abutting material sections and therefore promotes good welding regardless of dimensional and machining variations. At the same time, the rounded edges and the "free ends" of those edges are such that the vertical plane defined by the anterior and posterior surfaces of the beam is not obstructed by any outwardly projecting edges of the lamella. It is recessed into the front and back of the beam, which can be important to meet the vehicle manufacturer's specifications. Also, the central support legs are formed from the center of the thin plate (not from the side edges of the thin plate). By forming the central support leg first, and by forming the central support leg from the center of the sheet, the roll forming process is more balanced and controlled, and the lateral position of the sheet. Facilitates control of. In other words, the "wandering" of the sheet in the roll forming machine is reduced by first forming the central support leg. The reason for this is that the central support legs in this case act as an "anchor" during the subsequent forming of the lamella. This improved and precise position control of the lamella allows, as a result, to further reduce the "free end" tolerances of the edges, because wide tolerances are no longer required. It is conceivable that the "free end" of the edge can be reduced to as small as 4 mm or less and 2 mm or less, depending on the processing controls and features of the thin plate and roll forming process.

0021The tubular reinforcement beam 50 with a central support leg appears to have a high strength-to-weight ratio, resistance to longitudinal bending due to inward impact at its ends, and vertical impact from the center. It is particularly suitable for use as a reinforcement beam in vehicle bumper systems due to its torsional resistance to high rotational forces.

0022As mentioned above, the beam 50 (FIG. 2) is formed from a single unitary sheet in a continuous roll forming process (FIG. 6). The beam 50 includes a first edge 51 and a second edge 52, and seven wall sections 53-59 extending continuously between them. The first wall section 53 to the fourth wall section 56 form the first tubular portion, and the fourth wall section 56 to the seventh wall section 59 form the adjacent second tubular portion. At this time, the wall section 56 is a common common wall part. The wall sections 53-55 and the wall sections 57-59 combine to form a single tubular shape, with the central support legs extending horizontally (when in the vehicle mounting position). Formed by wall sections 56, wall sections 55 and 59 form a coplanar vertical front surface, and wall sections 53 and 57 form a coplanar vertical rear surface. The first edge 51 is deformed to form a radius CR1 of about 3 mm to 4 mm, with its tip 51'(ie, about 4 mm long or possibly 2 mm small). A lengthy "free end") extends such that the inner surface 61 of the first edge 51 is located parallel to the central wall section 56. The rounded bond angle portion 62 (formed by the fourth wall section 56 and the fifth wall section 57 at the front surface of the beam) is engaged with the rounded portion CR1 and the first tubular portion. Is welded to permanently set and fix.

0023At beam 50, the second edge 52 is also deformed inward to form a rounded portion similar to rounded portion CR1 (as in the beam shown, which is approximately 3 mm to 4 mm). When its end 52'extends parallel to the central wall section 56. The rounded portion CR1 is welded by engaging with the rounded bond angle 64 formed by the fourth wall section 56 and the third wall section 55. The illustrated beam 50 has a substantially rectangular cross section, at which time the central support leg divides the rectangle into adjacent first and second tubular portions of equivalent size. This cross section has been found to provide excellent flexural rigidity, torsional rigidity, and a relatively high strength-to-weight ratio.

0024The first wall section 53 in the illustration is a channel rib 65 (ie, an inwardly formed recess and also a "power rib". This rib 65 further strengthens the wall section 53, thereby strengthening the anterior surface of the beam as well as the first tubular section. The illustrated channel rib 65 is approximately centered along the wall section 53 and has a width diameter of approximately 10% to 40% (or more preferably approximately 20% to 30%) of the width of the wall section 53. And has a depth approximately equal to its width. The fifth wall section 57 also includes a channel rib 66 (similar to the rib 65 in size, shape and position), which strengthens the wall section 57 thereby the front of the beam and the second. Strengthen the tubular section. The rounded portion CR1 formed by the first edge portion 51 and the tip 51A, and the rounded portion CR1 formed by the second edge portion 52 and the tip 52A are inside the respective tubular portions formed by the rounded portions. It has a central point located at. The bottom of the illustrated channel rib has a semicircular shape. However, the depth and size of the channel ribs are shallow, deeper, wider, narrower, flat-bottomed, or otherwise modified to meet the specific functional requirements of the beam. It is conceivable that it may be formed.

0025In particular, the rounded shapes at the edges 51 and 52 and the corners that fit them cause them to form crevice ribs, which also reinforce the beam 50 and therefore with the channel ribs 65 and 66. Stabilizes the anterior / anterior and posterior / posterior surfaces of the beam 50 in a manner that is not completely different. On the front of the beam, the fissure ribs formed by the rounded shape of the front edge 51 and this bond angle combine with the two channel ribs 65 to create three ribs on the front of the beam 50. Each of these three ribs enhances the bending and torsional strength of the beam. Testing has shown that the stiffness of the beam can be increased sufficiently to offset the weight of any additional material that the channel ribs increase due to the need for wider lamellae in the manufacture of the beam. There is. The crevice ribs are roughly aligned with the central wall, and the cavity formed by the crevice ribs is about 3 to 4 times the material cross-sectional thickness of the thin plate. Specifically, the hollow portion of the fissure rib shown in the figure has a depth of about 3 mm to 4 mm based on a thin plate material thickness of about 0.8 mm to 1.2 mm. The laser weld is located at the bottom of the crevice where the material first comes into contact with the abutment.

0026Welds 70 and 71 are intended to be formed using laser welders 72 and 73 (FIG. 3). The welders 72 and 73 are located within one station S33, which offers great advantages in terms of space utilization, wiring and process control. Welds 70 and 71 (FIG. 2) are slightly spaced from the ends (ie, "free ends") at the first and second edges, for example reduced to about 4 mm or, in some cases, about 2 mm. It is formed on the material that abuts on the outside in the crevice so that it is located at a distance. The cross-engagement of the bent and abutting thin plate materials shown in the figure becomes inconspicuous and has some dimensional variation within the weld jig without adversely affecting line contact and welding operations. And allow dimensional control. The welders 72 and 73 are located within one station S33, but these welders are separate along the roll forming machine equipment if desired or if required by a particular application. It is conceivable that it can be placed in the station of.

0027In particular, the beam is symmetrical, including the cross-sectional profile and welds 70 and 71. This greatly helps to keep the beam uniform and linear during the roll forming and manufacturing operations (and meandering and non-linearity due to the heat of unbalanced welding and the shrinkage / movement of the material. Helps to avoid bending). Those skilled in the art of roll forming will recognize how the roll forming process is balanced in each of steps S1-S33 (FIG. 4). Specifically, those skilled in the field of roll forming manufacturing and design recognize the value of the perpendicularity of the central wall in step S7 and the value of the verticality of the outer wall in step S21, thereby. You will recognize the minimization of the roll forming process that is promoted.

0028A related method of manufacturing a tubular reinforcement beam 50 with a central wall section 56 for the bumper reinforcement beam 40 (see the roll forming machine in FIG. 3 and the beams in FIGS. 1 and 2). A step of supplying a thin plate 49 (see FIG. 3) including a first edge 51 and a second edge 52 (FIG. 2) and seven consecutive wall sections 53-59 extending between them. A step of bending the central wall portion in an orientation perpendicular to the remaining material (see steps S2 to S7) and a step of bending the edge tip (steps S3 to S7) to form channel ribs 65 and 66 (steps S3 to S7). (Starting in steps S3 to S9 and completing the channel ribs in steps S10 to S12), the first wall section 53 to the fourth wall section 56 are bent to form the first tubular portion and the fourth. The process of bending the wall section 56 to the seventh wall section 59 to form an adjacent second tubular portion (half is formed in steps S3 to S21 and the same is completed in steps S22 to S33). The first edge 51 is welded to the rounded joint corner 62 and the second edge while maintaining the correct cross-sectional shape of the continuous beam in the welding tool (see FIGS. 7 and 8). In the process of welding the portion 52 to the rounded coupling corner 64, in the sweeping station, the process of transforming the continuous beam into a longitudinally curved ("curved") shape, and in the cutting station. It includes a step of cutting a beam segment to a certain length to form a separate bumper reinforcement beam.

0029In particular, the channel ribs 65 of the first wall section 53 and the channel ribs 66 of the fifth wall section, combined with the central fissure at the front of the beam (straddling the central wall), have three channels on the surface of the beam. Provides a rib forming part. This provides excellent torsional and bending strength in the beam, as described above. Specifically, by testing, the channels and ribs that provide stability to the surface of the beam significantly improve impact strength and are consistent in impact strength (and energy absorption capacity) without increasing beam weight. It has been shown that it can result in increased sex), which is an unexpected and surprising result. The improvement in impact strength is due to several factors. For example, the weight of the beam of the present invention is of similar size without channel ribs, as the beam of the present invention still yields similar or improved impact test results while using thinner plate materials. Not increasing beyond the beam. In particular, thinner materials can tend to collapse into catastrophic conditions unpredictably / prematurely due to the physical energy (dynamics) generated during impact on thin sheet materials. Yes, and in some cases may increase variation and non-uniformity in impact strength during the test. However, the channel ribs and fissure ribs at the front of the beam of the present invention help stabilize the tubular structure of the beam and therefore an improved test even when thinner lamella materials are used. Bring results. This improvement was not expected when considering that the channel ribs and crevice ribs are at the front of the beam. Part of the reason this improvement was not expected is that the front channel ribs and crevice ribs bring the bending moment centerline closer (rather than farther from the bending moment centerline) in the sheet material. This is because some of them are located inward. In particular, materials located closer to the centerline of the bending moment will not contribute to the bending moment of the beam, which It may reduce the moment of inertia of bending with respect to the late beam. However, due to the physical energy of the impact, the stability of the beam wall can be very important for the impact performance of the beam. Also, some bumper tests cause an unbalanced torsional force in the vertical direction (as when the test impactor device strikes the beam above its centerline).

0030A related device 88 (FIG. 3) for the manufacture of a tubular reinforcement beam 50 with a central wall section 56 for the bumper reinforcement beam 40 is an in-line sweep station 90 and a cutter 91. It is equipped with a roll mill 89 having a. The roll mill 89 is a plurality of rolls configured to form a sheet 49 including a first edge 51, a second edge 52 and seven wall sections 53-59 extending continuously between them. Includes. These rolls include a first region 92 of the roll forming station, which region forms a central support leg with a thin outer wing extending approximately perpendicular to the central support leg. It has multiple sets of rolls positioned so as to. The first region 92 of the roll forming station also forms a rounded edge of the sheet. The second region 92'of the roll forming station contains a plurality of sets of rolls, which are bent from the first wall section 53 to the fourth wall section 56 to form a first tubular portion. And the fourth wall section 56 to the seventh wall section 59 are bent to form an adjacent second tubular portion in a state where one central support leg is common to both tubular portions. It is positioned and configured to do so. The first welder 72 and the second welder 73 are positioned to weld the first edge 51 to the bonded inner surface of the rounded corner 62, as well as the second edge. 52 is positioned to weld to the rounded corners 64 to be joined. The first welder 72 is positioned above the beam and the second welder 73 is below the beam with the laser beam of this welder oriented at an angle, as described below. It is positioned in.

0031It can be seen that the apparatus of the present application can utilize a roll mill in which the horizontal axis supports the forming roll, or instead can utilize a roll mill in which the vertical axis supports the forming roll. In a vertical axis mill, the laser welder may operate from the opposite side of the beam or partially above the beam. The advantage of a vertical axis roll mill is that the welder is positioned to the side and / or above the weld so that gravity can be used to remove debris and debris from the weld and drop it. In a horizontal axis roll mill, the laser acts from the top and bottom positions with respect to the beam. The bottom position on one side of the welder can cause problems related to falling debris, which is solved by the innovations of the invention as described below.

0032As shown by the illustrated form in FIGS. 3 and 4, it is preferable to configure a device in which both welds are formed at one station while welding is being performed at the same time. One welder 72 is located above the weld position and another welder 73 is located below the weld position but well upstream (or downstream) of this weld position. The bottom welder is positioned and shielded from being adversely affected by scattered and falling debris. For example, the bottom welder in the figure is located 15 degrees upstream of the actual weld point from the vertical line. Also, if necessary (depending on the distance of the laser beam generator from the weld position), a shield may be used to physically shield the laser generator from the weld. The illustrated shield is located so that it does not interfere with the laser beam (which defines the line), but the laser generator drops the falling debris (the falling debris first moves laterally and then by gravity at the end of its fall path). It is a physical protective wall that is placed to protect it from (which tends to arc when it falls towards it). It is conceivable that the shielding material also includes an air shield provided by the directed airflow. In particular, the focal length of the laser beam of a laser welder can be up to 36 inches (about 91.4 cm), and there are several laser beams such as gas (CO2) type, solid type, fiber type, or disk type. It can be any of the various types.

0033In the process shown in FIG. 4, the central support legs are first oriented perpendicular to the horizontal plane (extending along the line level of the roll forming machine) from the center of the sheet in the first few steps S1 to S7. It can be seen that it is formed into. This keeps the lamella fixed and centered during the roll forming process, thus eliminating (or significantly reducing) the tendency of the lamella to wander or slide laterally during the forming process. It can be seen that due to the high strength characteristics of this thin plate and the thickness and width of the thin plate, a large lateral force is generated during the roll forming process. By first forming the central support legs in a vertical state, the lateral position of the lamella is much easier to control and more essentially controlled / controllable. The rounded portion is also formed in the plurality of edges of the thin plate in steps S1 to S7. After that, adjacent tubular portions are formed on both opposite sides of the common central support leg portion. As a result, in the processing of the present application in FIG. 4, the number of roll forming steps is 290 ksi (290 kilograms per square inch, about 2000 MPa, about 20389.9 kgf / cm.²) Even when forming thin plates with super-tensile strength, it can be reduced to as many as 33 steps (see Figure 4), which is dramatic, surprising and unexpected from known methods. It is considered an improvement. In particular, reducing the number of forming steps can be very beneficial, as reducing the number of steps reduces the cost of machine tool equipment (ie, the number of forming rolls required) and the length of the roll forming equipment. Reduces the number of roll forming stations (ie, reduces the number of roll forming stations) and reduces the overall machining time (ie, the cycle time from the initial flat sheet to the double tube beam shape is shorter). Because it can be done.

0034FIG. 5 shows a seam tracking disk 90'used to copy and control the crack 80. (In FIG. 5, the disc 90'is unfolded apart, but this disc is intended to physically engage the beam 50 and follow along the crevice.) Disc 90'. Follows the valley of the fissure 80 to facilitate the welding process. Specifically, the disc 90'is a rotating disc that sits inside an area for continuous weld seams and resembles a pizza cutter. The laser welder is located away from this disc in the weld valley. As shown, the disc 90'can be used to mimic a fissure at both the top and bottom of the beam 50.

0035FIG. 6 is a cross section of the modified beam 50A, which is similar to FIG. 2 but has a tubular portion of a different width. Specifically, one tubular portion of the beam 50A is approximately twice the width of the other tubular portion. However, these tubulars share a common central wall. In addition, each of these tubular portions has channel ribs of similar size and shape, and there are also fissure ribs formed across the central support leg. In beam 50A, similar and identical features, features and components are identified using the same code but with a letter (such as "A"). This is done to reduce redundant explanations. It is considered that the beam 50A can and incorporates many features of the beam 50, so that individual explanations of the codes in the beam 50A are not necessary for the bumper reinforcement beam and related manufacturing processes. It will be understood by those skilled in the art.

00363, 7 and 8 show the welding station 100 at the end of the roll forming machine and when leaving the roll forming machine. In FIG. 7, the lamella is shown as already molded in the roll forming machine and is proceeding in the traveling direction D1. The box welding jig 102 is positioned in-line with the partially molded beam 50. The laser welder 103 on the top side and the laser welder 103 on the bottom side are located at the welding station so that the box-shaped welding jig does not interfere with the laser beam of each welder that hits the target contact material of the beam 50. , Is positioned. The bottom side laser welder 103 is located slightly upstream of the box welding jig 102, the welding laser 104 being oriented with an angle downstream, whereby the welding laser beam 104 is desired. It hits the beam 101 at the position and heats and welds the contact material of the beam 101. Lasers have focal lengths up to 36 inches, depending on the type of laser. There is no minimum laser distance from the weld position of beam 101. For example, it is conceivable that the laser type may be a gas (CO2 or the like), or may be a solid state laser type, a fiber laser type, or a disk laser type. The maximum angle A1 of the laser 104 with respect to the reinforcement beam 101 is approximately 15 degrees from the vertical line (ie, from the plane perpendicular to the side of the beam 50). Where necessary or desired, a physical shield 105 is used to shield and protect the laser source 106 from debris from the weld process. The physical shield 105 may be a downstream air knife or air jet, or may include a physical panel.

0037The adjustable box welding jig 102 (FIG. 8) is located at the welding station and is designed to set and hold the final shape of the roll forming beam during the welding process. The illustrated adjustable jig 102 includes an external steel box formwork 110, a top-side external mandrel 111 and a bottom-side external mandrel 112, and an adjustable side-side exterior that is pressed inward by actuators 115, 116. Includes mandrel 113,114 and. The actuator can be powered or active (such as a hydraulic cylinder), or the actuator can be adjustable and passive (box-shaped by supplying inward pressure of the desired magnitude). It is conceivable that the external mandrel in the welding jig 102 can be adjusted to maintain the desired shape (screwed bolt, etc.). Two rods are shown, which extend from the actuator 115 through the frame 110 to a position where they can be attached to the external mandrel 111. However, it is intended that alternative connection and motivating configurations can also be configured.

0038Internal mandrel 117,118 are located within the tubular portion 121,122 of the double tube beam 120, respectively, and internal mandrel 117,118 is fastened by cable 123,124 extending to the upstream fixed column 125 located on the roll forming machine. At this time, in the roll forming machine, the sheet is open sufficiently laterally to position the fixed column 125 (Fig. 3) to hold the cables 123,124 (Fig. 8). Although beam 50 is shown, it is conceivable that the beam could be a similar beam 50A or a beam with other modifications. The illustrated internal mandrel 117, 118 is a split mandrel with opposed mandrel semifields 126, 127, respectively, urged away by a spring 128 (eg, a fluid pressure spring, a mechanical spring, or other spring). The internal mandrel 118 also includes opposed mandrel semifields 130,131 that are urged away by a fluid pressure spring 132. However, depending on the situation, it is conceivable that a solid internal mandrel of the dress can be used on each side. Laser access openings are provided in the box jig frame 110 and the external mandrel 111,112, at which time the illustrated laser access opening 129 penetrates the bottom and top of the box form 110 and is a top side external mandrel. Provides access for the laser beam penetrating the 111 and the bottom side external mandrel 112.

0039The internal springs 128 and 132 and the split internal mandrel 117,118 are combined with the inwardly urging actuator 115,116 and the external mandrel 113,114 when the beam 101 is welded to the jig through the welding station 100. To maintain the desired outer shape of the beam 101. In particular, there is a sliding surface P1 defined between the top side outer mandrel 111 and the tops of the side side outer mandrel 113,114. There is also a sliding surface P2 defined between the bottom side outer mandrel 112 and the bottom of the side side outer mandrel 113,114. The sliding surface P1 is partially defined by the outer surface of the tip of the front end, which is aligned with the front surface of the beam 101 and is given the roundness of the central support leg. The sliding surface P2 is partially defined by the outer surface of the tip of the rear end portion which is aligned with the rear surface of the beam 101 and is provided with the roundness of the central support leg portion. Within the welding station, pressure from the internal and external mandrel of the welding jig causes the sheet material to move and deform along sliding surfaces P1 and P2 to exact known locations. This improves the dimensional consistency and dimensional accuracy of the cross-sectional shape of the beam before (and during) the welding process. This configuration also allows more accurate and consistent control of the pressure on the contact surface where welding will take place for optimum welding conditions.

0040It should be understood that modifications and modifications can be made to the above configurations without departing from the concept of the present invention, and that such concept is otherwise provided by its wording within the appended claims. It should be understood that it is intended to be covered by the claims unless otherwise stated.