Multitubular beam with forged joints

Abstract

A reinforcing beam for an automotive component is continuously formed with a metal sheet that is roll-formed to have at least one tubular portion extending along the length of the reinforcing beam. A solid forge weld is formed between an edge of the metal sheet and an intermediate portion of the metal sheet to close a seam extending along the tubular portion of the reinforcing beam. Prior to forming the solid forge weld, a selected portion of the metal sheet is heated to a desired welding temperature with high frequency electrical current supplied by electrical contacts on opposing sides of the weld seam. The desired welding temperature can burn off any galvanized coating on the metal sheet in the selected portion prior to forming a solid forge weld that is generally free of zinc inclusions.

Description

[Technical field]

[0001] This application claims the benefit of and priority under 35 U.S.C. §120 of U.S. Patent Application Publication No. 17 / 461,049, filed August 30, 2021, which is incorporated by reference in its entirety herein. FIELD OF THE DISCLOSURE This disclosure relates to vehicle structural and reinforcing beams and related methods of roll forming manufacture and beam welding. [Background technology]

[0002] Vehicles undergo various tests mandated by government regulations and insurance certifications, such as tests for impact energy management and absorption. The results of these impact tests may depend on various vehicle components and structural designs, including bumper assemblies and associated bumper reinforcement beams. To protect the performance and structural integrity of vehicle components over time, it is known to galvanize or provide a protective zinc coating on the steel components of a vehicle, which may prevent rust or iron oxide from developing on the steel components. However, galvanized sheet metal may be more difficult to form and weld, especially with respect to laser welding in roll forming operations. Also, depending on the design of the roll formed beam, with or without a galvanized coating, laser welding may be difficult due to the shape of the material and the condition of the seams. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2020 / 0164820 Summary of the Invention [Means for solving the problem]

[0004] The present disclosure provides a multi-tubular reinforcement beam and a method for continuously forming the same. The beam may be used as a structural component or energy absorber of a vehicle, such as a bumper beam. Initially, a roll of metal sheet stock may be unwound in a generally horizontal plane for processing, such as by unwound at a generally constant speed toward and into a roll former. The metal sheet may be a high-strength steel, such as a martensitic steel. The roll former is configured to form the sheet into a beam having at least one longitudinally extending tubular portion that is closed with a weld seam formed between an edge of the sheet and an intermediate portion of the sheet. The weld seam may be formed in a high-frequency electric resistance welding process, such as by contacting the formed sheet with a pair of electrical contacts that slide on opposing sides of the weld seam just before entering a closing press roll that closes the weld seam. The resistance of the high-frequency current supplied by the electrical contacts heats the outer surfaces of the two opposing portions of the weld seam to an appropriate welding temperature. The two heated opposing portions are then pressed together by the closing press roller to form a solid forge weld. In some examples, the metal sheet may include a galvanized coating such that when the exterior surface of the sheet is heated, the galvanized coating is at least partially burned off to form zinc oxide gas and leave the forge weld formed by the closing press rolls substantially intact.

[0005] According to one aspect of the disclosure, a reinforcing beam for an automotive component includes a roll of metal sheet formed to have a pair of tubular portions sharing a common center wall and extending along the length of the reinforcing beam. A solid weld is formed in-line with the roll-formed metal sheet between an edge of the metal sheet and an intermediate portion of the metal sheet to close a seam around one of the pair of tubular portions at an end of the common center wall. The seam formed by the solid weld extends continuously along the length of the reinforcing beam. Prior to forming the solid weld, the outer surfaces of the edge of the metal sheet and the intermediate portion of the metal sheet are electrically resistance heated to a desired forge temperature.

[0006] Implementations of the present disclosure may include one or more of the following optional features. In some implementations, the solid forge weld has a narrow heat affected zone of 1 mm to 2 mm in width. In some examples, a second edge of the metal sheet is welded at a second forge weld at a second end of the common central wall of the reinforcing beam to surround the other of the pair of tubular portions extending along the length of the reinforcing beam. The reinforcing beam may include a front impact surface defined, for example, by a front wall of the pair of tubular portions. The front wall of at least one of the pair of tubular portions may include a stiffening rib protruding into an interior volume of the respective tubular portion to stiffen the front impact surface.

[0007] In some implementations, the solid weld is formed with heat generated by the electrical resistance of high frequency current supplied by the electric resistance welding junction and closed press rolls pressing heated surfaces of the metal sheets together. In some examples, the metal sheets include high strength steel, whereby the desired welding temperature is below the melting temperature of the high strength steel of the metal sheets. In some implementations, the metal sheets include a galvanized coating, whereby the desired welding temperature burns off the galvanized coating on the metal sheets at the outer surfaces before forming the solid weld.

[0008] According to another aspect of the disclosure, a reinforcing beam for an automotive component includes a galvanized metal sheet roll-formed to have a tubular portion extending along the length of the reinforcing beam. A solid forge weld is formed between an edge of the galvanized metal sheet and an intermediate portion of the galvanized metal sheet to close a seam extending along the tubular portion of the reinforcing beam. Prior to forming the solid forge weld, an outer surface of the edge of the galvanized metal sheet and the intermediate portion of the galvanized metal sheet are heated to a desired welding temperature with a high frequency current delivered by an electrical contact. The desired welding temperature burns off the galvanized coating on the galvanized metal sheet at the outer surface prior to forming a solid forge weld that is substantially free of zinc inclusions.

[0009] According to yet another aspect of the present disclosure, a method of continuously forming a galvanized reinforcing beam may be performed by unwinding a roll of galvanized sheet metal in a generally horizontal plane. The metal stock is roll formed through a set of multiple roll stations to form a tubular shape in which the edge sections of the sheet metal generally contact the middle section of the sheet metal. The outer surfaces of the edge sections of the sheet metal and the middle section of the sheet metal are heated to a desired welding temperature with high frequency current supplied by a pair of electrical contacts that contact the sheet near the outer surfaces. This causes the galvanized coating on the sheet metal to at least partially burn off at the heated outer surfaces. Thereafter, a solid weld is formed on the heated outer surfaces of the edge sections and the middle section of the sheet metal by pressing the outer surfaces together with a closing press roll. The solid weld is continuously formed to close the seam of the tubular shape of the reinforcing beam.

[0010] Optionally, after the first tubular portion is closed at the first forge weld, the galvanized metal sheet may be rolled in a second set of roll formers to bring opposing edges of the galvanized metal sheet into close proximity with the walls of the tubular portion, whereby these adjacent outer surfaces may be heated with high frequency current supplied by a second pair of electrical contacts to form a second forge weld that closes the seam along the second tubular portion of the reinforcing beam. In some examples, the metal sheet is unrolled longitudinally at a generally constant speed, rolled, and welded.

[0011] The details of one or more implementations of the disclosure are set forth in the accompanying drawings and the description below. Other aspects, advantages, objects and features will become apparent from a consideration of the following specification in conjunction with the drawings. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic side view of a vehicle having a bumper assembly and a rocker component. [Diagram 2] FIG. 2 is a front perspective view of a reinforcing beam. [Diagram 3]FIG. 3 is a rear perspective view of the reinforcing beam shown in FIG. 2. [Figure 3A] FIG. 4 is a cross-sectional view of the reinforcing beam taken along line IIIA-IIIA shown in FIG. 3. [Figure 4] FIG. 3 is a schematic side view of an apparatus configured to manufacture the reinforcing beam shown in FIG. 2. [Diagram 5] 3 is a cross-sectional view of the reinforcing beam of FIG. 2 at an intermediate forming step having a forge weld. [Figure 5A] FIG. 6 is an enlarged view of the weld location shown in cross section A of FIG. 5, showing a schematic of the welded contact points. [Figure 6] 3 is a cross-sectional view of the reinforcing beam of FIG. 2 in a forming step with a second forge weld. [Figure 6A] FIG. 7 is an enlarged view of the weld location shown in cross section A of FIG. 6, showing the weld contact point in schematic form. [Figure 7] 11A-11C are cross-sectional views of additional examples of reinforcing beams at intermediate forming steps. [Figure 8] 8 is a cross-sectional view of the reinforcing beam of FIG. 7 at a later forming step, having two forge welds. [Figure 8A] FIG. 9 is an enlarged view of the weld location indicated by cross section A in FIG. 8, showing the weld contact point in schematic form. [Figure 8B] FIG. 9 is an enlarged view of the weld location shown in section B of FIG. 8, showing the weld contact point in schematic form. [Figure 9] FIG. 13 is a front perspective view of an additional reinforcing beam. [Figure 10] FIG. 10 is a rear perspective view of the reinforcing beam shown in FIG. [Figure 10A] FIG. 11 is a cross-sectional view of the reinforcing beam taken along line XA-XA shown in FIG. 10. [Figure 11A] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 11B] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 12A] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 12B] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 13A] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 13B] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 14A] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 14B] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 15A] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 15B] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 16A] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 16B] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 17A] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 17B] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 18A] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 18B] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 19A] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 19B] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 20A] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 20B] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 21A] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 21B] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 22A] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 22B] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 23A] FIG. 13 is a cross-sectional view of an additional reinforcing beam. [Figure 23B] FIG. 13 is a cross-sectional view of an additional reinforcing beam. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Like reference numbers refer to like parts throughout the drawings.

[0014] Referring now to the drawings and the illustrative embodiments depicted therein, a vehicle 100, such as that shown in FIG. 1, has various structural beam components, including a bumper assembly having a bumper reinforcement beam 10a and a sill assembly having a rocker reinforcement insert 10b. The bumper assembly includes a crush can 102 attached to an end portion of the reinforcement beam 10a. The crush can 102 is adapted to be attached directly or indirectly to the vehicle frame or an end section or tip of the vehicle frame. When attached to the vehicle frame, the crush can 102 supports and positions the reinforcement beam 10a across the vehicle 100, such as at the front end shown in FIG. 1. The rear end of the vehicle may also include a bumper reinforcement beam to similarly mitigate impact damage and intrusion into the vehicle. In other examples, the bumper beam may be used with different types of bumper assemblies or support structures at the front or rear ends of the vehicle.

[0015] Also, as shown in FIG. 1, for example, a vehicle 100 may have a sill assembly that supports lower components of the frame, such as A-pillars, B-pillars, cross members, or the like. The sill assembly may include a sill inner and a sill outer that surround a hollow interior. A reinforcing insert 10b extends longitudinally through the hollow interior between the sill inner and sill outer. The reinforcing insert 10b is provided to stiffen and reinforce the sill assembly, such as to reduce the intrusion distance from a side impact of the vehicle. The bumper reinforcing beam 10a, the reinforcing insert 10b, and other reinforcing beams of the present disclosure may be formed from galvanized metal sheet. Vehicle frames and body structures may have various designs and configurations for different styles and types of vehicles.

[0016] As shown in Figures 2-3A, a reinforcement beam 10 is provided that may be continuously formed using a metal sheet passing through a roll former and an in-line welder. The welder uses electric resistance welding to form a forge weld along at least one weld seam that encircles the tubular shape of the beam. The reinforcement beam 10 may be used structurally or as an energy absorber in a vehicle, such as a bumper reinforcement beam 10a (Figure 1), a rocker reinforcement insert 10b (Figure 1) or another vehicle structural component. The beams described herein may be adapted for a variety of structural or reinforcement applications, whether straight or curved longitudinally, to accommodate a particular vehicle design, such as bumper beams, roof bows, headers, pillars, rocker rails, seat members and door beams of a vehicle frame, among other possible vehicle and non-vehicle related components.

[0017] Generally, to form the reinforcing beam 10, a roll of sheet metal 12 is first unwound in a generally horizontal plane for processing, such as by unwinding at a generally constant speed towards and into a roll former 14, as shown diagrammatically in Fig. 4. The roll former 14 is configured to repeatedly form the sheet 12 into the reinforcing beam 10 using a series of roll tooling or forming rolls 16a, 16b supported on a roll stand. The roll tooling or forming rolls 16a, 16b may successively form the sheet 12 to have at least one longitudinally extending tubular portion, for example two tubular portions 18, 20, as shown in Fig. 3. The tubular portions 18, 20 are closed at weld seams 22a, 22b, respectively. Weld seams 22a, 22b are formed between edges 24a, 24b of sheet 12 and intermediate portions 26a, 26b of sheet 12 such that weld seams 22a, 22b form T-joints or generally T-shaped joints.

[0018] The weld seam 22a, 22b may be formed by a high frequency electric resistance welding process. For example, as shown in FIG. 4, high frequency contact welding may be performed by contacting the formed sheet 12 with a pair of electrical contacts 28a, 28b on opposite sides of the weld seam near or just before entering closing press rolls 30a, 30b that close the weld seam 22a, 22b while simultaneously pressing the heated edge and heated middle portion of the sheet together to form the weld. The desired welding temperature is therefore below the melting temperature of the high strength steel of the galvanized metal sheet. The electrical contacts maintain contact with and slide along the sheet 12 as the sheet 12 moves continuously through the welding station. The resistance of the electrical current supplied by the pair of electrical contacts 28a, 28b generates heat at the outer surface of the edge and middle portion of the sheet 12 where these portions of the sheet 12 bond together. When the outer surfaces of the sheet 12 are heated by the electrical current supplied by the electrical contacts 28a, 28b, the galvanized coating is at least partially burned off or vaporized at the edges and middle portions of the sheet 12, forming zinc oxide gas. By vaporizing the galvanized coating before the outer surfaces join at the weld seam 22a, 22b to form a weld, these zinc oxide gases generally do not interfere with the quality and consistency of the solid forge weld formed by the closing press rolls 30a, 30b. The pressure applied by the closing press rolls 30a, 30b may reduce or eliminate the entrapment of zinc oxide gas in or near the resulting weld, so as to form a solid forge weld that is generally free of zinc inclusions or other defects associated with the zinc oxide gas generated in the welding process.

[0019] As shown in Figures 2-3A, the reinforcing beam 10 has two adjacent tubular portions 18, 20 that share a common central wall 32 extending along the length of the beam 10. The tubular portions 18, 20 of the beam 10 are planar in shape and also have front walls 34, 36 and rear walls 38, 40, respectively, that are generally aligned with one another. The upper tubular portion 18 comprises the upper wall 42 of the beam 10. The lower tubular portion 20 comprises the lower wall 44 of the beam 10. The front walls 34, 36 of the tubular portions 18, 20 are aligned substantially in a common plane with one another to form the outwardly facing or impact surface of the beam 10 when used as a bumper reinforcing beam. Similarly, the rear walls 38, 40 are generally planarly aligned with one another and are substantially parallel to the front walls 34, 36. Additionally, the upper and lower walls 42, 44 are substantially parallel to each other and to the central wall 32, and generally perpendicular to the front and rear walls 34, 36, 38, 40. The corners between the walls of the tubular portions 18, 20 of the beam 10 have a radius of curvature that is generally dictated by the type of material and thickness of the metal sheet 12, e.g., a radius of curvature that is approximately equal to or greater than four times the thickness of the metal sheet 12. It is understood that additional embodiments of the beam can assume various shapes and orientations from those shown in Figures 2-3A and can include alternative dimensional proportions, such as for different applications of the beam.

[0020] As further shown in Figures 2-3A, the front walls 34, 36 of the tubular portions 18, 20 each include a stiffening rib 46 that protrudes into the interior volume of the respective tubular portion 18, 20 to stiffen the front impact surface of the stiffening beam 10. The illustrated stiffening rib 46 has a width diameter that is about 10%-40% of the width of the corresponding wall section (or more preferably about 20%-30% of the width of the corresponding wall section) and a depth that is approximately equal to the width diameter. The bottom of the illustrated stiffening rib 46 is semicircular in shape. Nevertheless, it is contemplated that the depth and size of the stiffening rib may be made shallower, deeper, wider, narrower, flat-bottomed, or otherwise modified to meet the particular requirements of the beam.

[0021] 4, the sheet stock 12 unwound from the roll may have a thickness of about 1 mm to 1.5 mm and may have a galvanized coating, such as an electroplated galvanized coating, to provide a generally uniform thickness of less than about 5 mils (0.127 mm). In a further example, it is contemplated that the sheet of steel may have a thickness of about 0.8 mm to 3.0 mm, and the sheet may have a tensile strength of about 800 to 2000 MPa (i.e., about 120 to 290 ksi). Additionally, the beams of the present invention may be made of a variety of materials, such as high strength steels, including AHSS (advanced high strength steels). It is also understood that additional examples of sheet stock may be ungalvanized or may be galvanized in a different manner, such as hot dip galvanizing.

[0022] As shown in FIG. 4, after the steel sheet 12 passes through a first set of rolling tools or forming rolls 16a supported on a roll stand, the steel sheet 12 may be formed to have at least one tubular shape having a generally consistent cross-sectional shape along its length. In forming the tubular shape, the first set of forming rolls 16a may position an edge 24a of the sheet 12 proximate to a middle portion 26a of the sheet 12 just prior to closing the first tubular portion 18 of the beam 10. With a small gap remaining between the edge 24a and the middle portion 26a of the sheet 12, the intermediate formed sheet 12 successively enters a welding station that places a pair of electrical contacts 28a on opposite sides of the gap. The electrical contacts transmit high frequency electrical current to the partially formed beam. Specifically, as shown in FIG. 5A, an electrical contact 28a is placed in contact with a portion of the sheet 12 proximate the edge 24a of the sheet 12. Another electrical contact 28a is placed in contact with a portion of the sheet 12 proximate the middle portion 26a of the sheet 12. The proximity of electrical contacts 28a to weld seam 22a generally results in a high current density that generally provides a corresponding high welding efficiency along with a small heat affected zone. As shown in Figure 5A, electrical contacts 28a may be positioned in contact with adjacent adjacent surfaces of sheets 12 such that electrical current may be concentrated along the contacted surfaces of the sheets.

[0023] Electrical current travels from one electrical contact 28a to the other electrical contact 28a at the outer surface of the edge 24a of the sheet 12 and the intermediate portion 26a of the sheet 12 to generate heat with the resulting electrical resistance. The heat is generally concentrated where the portions of the sheet 12 join together, such as in a V-shape. The pair of electrical contacts 28a directs the current along the geometric V-shape formed by the edge 24a and intermediate portion 26a of the sheet 12. As the current flows along the edge 24a and intermediate portion 26a, they are heated to an appropriate welding temperature that is below the melting temperature of the sheet material.

[0024] As further shown in FIG. 5A, the electrical contacts 28a may include a spring-loaded contact plate that is biased against a desired portion of the sheet 12. A tip portion of the spring-loaded contact plate may directly engage the sheet 12 to slide along the outer surface of the sheet 12 as the sheet moves through the welding station. However, it is contemplated that the electrical contacts in additional embodiments may alternatively include a contact wheel or disk. The contact wheel or disk rolls against the sheet to reduce friction between the electrical contact and the sheet surface that may lead to deterioration of the tip portion of the contact plate, and, in the case of galvanized sheet metal, the tip portion scrapes zinc from the galvanized coating to prevent it from accumulating on the tip portion of the electrical contact or elsewhere.

[0025] Also, in the example using galvanized sheet metal, when the outer surface of the sheet 12 is heated by the electrical contacts 28a to the desired welding temperature, the galvanized coating is at least partially burned off or vaporized at the edge 24a and middle portion 26a of the sheet 12 to form zinc oxide gas. The radio frequency current supplied to the opposing portions of the seam can be selected or configured to heat the outer surfaces of the edge 24a and middle portion 26a of the sheet 12 to reach the desired welding temperature for the particular material and sheet thickness when the mating surfaces of the sheets contact. In addition to providing the desired welding temperature at the mating weld seam 22a, the radio frequency current can also be selected or configured in conjunction with the speed of the sheet so that the edge 24a and middle portion 26a of the sheet 12 reach a sufficient temperature for a sufficient time to burn off or vaporize the galvanized coating at the mating surfaces. The radio frequency current can be 80KHz to 800KHz, or 150KHz to 800KHz, or 150KHz to 450KHz, or approximately 350KHz.

[0026] Immediately after passing the electrical contact 28a, the sheet 12 enters a closing press roll 30a which presses the edge 24a and the middle portion 26a of the sheet 12 together to close the weld seam 22a, as shown in the cross-section shown in Figures 5 and 5A. The tubular portion 18 is closed at the weld seam 22a which is formed continuously between the edge 24a and the middle portion 26a of the sheet 12 along the length of the reinforcing beam 10 to form a T-joint or a generally T-shaped joint at the weld seam 22a. As shown in Figure 5A, the forge weld 22a may be located at the rear face of the front impact wall of the reinforcing beam 10 and between the central wall 32 and the front walls 34, 36 of the tubular portions 18, 20. Thus, there may be no welds at the front impact face of the reinforcing beam 10.

[0027] The pressure applied by the closing press rolls 30a may reduce or eliminate the entrapment of zinc oxide gas in or near the resulting weld, so as to form a solid forge weld that is generally free of zinc inclusions or other defects associated with zinc oxide gas generated in the welding process of galvanized sheet metal. Additionally, a solid forge weld formed by radio frequency contact welding using closely spaced electrical contacts 28a may have a narrow heat affected zone, such as about 1 mm to 2 mm.

[0028] After forming the first forge weld along the weld seam 22a, the sheet 12 is further formed using another set of forming rolls 16b to have a cross-sectional shape that positions the other (now only cut) edge 24b of the sheet 12 adjacent to another intermediate portion 26b of the sheet 12 just prior to closing the second tubular portion 20 of the beam 10, as shown in FIG. 6. With a small gap remaining between the edge 24b and the intermediate portion 26b of the sheet 12, the formed sheet 12 enters another welding station where a pair of electrical contacts 28b are placed on opposite sides of the gap to transmit high frequency current. Specifically, as shown in FIG. 6A, the electrical contacts 28b are placed in contact with the portion of the sheet 12 adjacent to the edge 24b. Another electrical contact 28b is placed in contact with the portion of the sheet 12 adjacent to the intermediate portion 26b.

[0029] The resistance of the electrical current provided by the pair of electrical contacts 28b generates heat at the outer surfaces of the edge 24b of the sheet 12 and the middle portion 26b of the sheet 12 where these portions of the sheet 12 join together in a V-shape. When the outer surface of the sheet 12 is heated by the electrical current provided by the electrical contacts 28b, the galvanized coating is at least partially burned off or vaporized at the edge and middle portion of the sheet 12, forming zinc oxide gas. By vaporizing the galvanized coating before the outer surfaces join to form a weld at the weld seam 22b, these zinc oxide gases generally do not interfere with the quality and consistency of the solid forge weld formed by the closing press rolls 30b. The pressure applied by the closing press rolls 30b may reduce or eliminate the entrapment of zinc oxide gas in or near the resulting weld to form a solid forge weld that is generally free of zinc inclusions or other defects associated with process generated zinc oxide gas.

[0030] Immediately after passing the second pair of electrical contacts 28b, the sheet 12 enters a second closing press roll 30b which presses the edge 24b and middle portion 26b of the sheet 12 together to close the weld seam 22b, as shown in the cross section shown in FIG. 6. The second tubular portion 20 is closed at the weld seam 22b which is continuously formed between the edge 24b and middle portion 26b of the sheet 12 along the length of the reinforcing beam 10 to form a T-joint at the weld seam 22b. The second weld seam 22b is sometimes referred to as a T-joint, but the edge portion 23 of the sheet 12 having the edge 24b is angled inwardly from the plane of the rear wall 40 as it extends toward the central wall 32. The end portion 23 thereby joins with the central wall 32 at an oblique orientation that is not generally perpendicular to the joining middle portion 26b of the central wall 32. However, the angular orientation of edge portion 23 in other examples may be reduced such that edge 24b joins a corner portion between center wall 32 and rear wall 38 of first tubular portion 18. Second edge 24b of galvanized metal sheet 12 is welded with the wall of tubular portion 18 of reinforcing beam 10 to surround second tubular portion 20. Forge weld joints 22a, 22b are located at opposite ends of common center wall 32 as shown in FIG.

[0031] Referring again to FIG. 4, an apparatus for manufacturing a reinforcing beam may include an in-line sweep station 48 and a cutoff 50. Such a sweep station 48 may impart a longitudinal curvature to the beam, such as to impart a longitudinal shape to a bumper beam corresponding to a vehicle front end design. At the in-line sweep station 48, forge welds are formed along the beam that are capable of withstanding longitudinal bending of the beam. It should be understood that the roller former may utilize a roll mill having a horizontal axis supporting the forming rolls, or alternatively, a roll mill having a vertical axis supporting the forming rolls.

[0032] As shown in FIGS. 7-8B, an additional example of a reinforcing beam 110 is formed with a steel sheet 112 to provide two adjacent tubular sections 118, 120 that share a common central wall 132. In the example shown in FIG. 7, a first outer section and a second outer section of the metal sheet extend in generally opposite directions from a first end and a second end of the common central wall 132. The first and second outer sections of the metal sheet are formed in the same rotational orientation relative to the central wall 132. The first outer section is formed to be attached to or near the second end of the central wall 132 to surround the first tubular section 118. The second outer section is formed to be attached to or near the first end of the central wall 132 to surround the second tubular section 120. The first and second outer sections may be formed simultaneously to form ends of the outer sections toward the ends of the central wall 132. The first and second outer sections each include a recessed area at their integral connection with the center wall to provide an area for attaching an edge of the sheet 112 .

[0033] As shown in FIG. 8, the first outer section is shaped to define a first wall 138, a second wall 142, and a third wall 134 which together with the common central wall 132 form the first tubular portion 118. The second outer section is shaped to define a fifth wall 140, a sixth wall 144, and a seventh wall 136 which together with the common central wall 132 form the second tubular portion 120. In an installation orientation as a bumper reinforcement beam as shown in FIG. 1, the first and fifth walls 138, 140 define the rear wall of the reinforcement beam 110, the second wall 142 defines the upper wall, the sixth wall 144 defines the lower wall, and the third and seventh walls 134, 136 define the front wall of the reinforcement beam 110. A recessed area 139 on the fifth wall 140 allows the first and fifth walls 138, 140 to be positioned in general planar alignment with one another to define the rear wall. Similarly, the recessed area on the third wall 134 allows portions of the third and seventh walls 134, 136 at the front impact face of the beam to be positioned in generally planar alignment with one another across the front wall. As further shown in FIG. 8, the upper and lower walls 142, 144 are substantially parallel to one another and to the central wall 132, and generally perpendicular to the front and rear walls 134, 136, 138, 140.

[0034] With further reference to Figures 7-8B, when the sheet is formed into a multi-tubular shape by a roll former, the forming rolls position the edges 124a, 124b of the sheet 112 proximate recessed areas 135, 139 in the intermediate portions 126a, 126b of the sheet 112 just prior to closing the tubular portions 118, 120 of the beam 110. With a small gap remaining between the edges 124a, 124b and the intermediate portions 126a, 126b of the sheet 112, the formed sheet 112 successively enters a welding station which places a pair of electrical contacts 128a, 128b on opposite sides of the gap. The electrical contacts transmit high frequency electrical current to the partially formed beam. Specifically, as shown in Figures 8A and 8B, the electrical contacts 128a, 128b are placed in contact with portions of the sheet 112 proximate the edges 124a, 124b of the sheet 112. The other electrical contacts 128a, 128b are placed in contact with the intermediate portions 126a, 126b of the sheets 112. The proximity of the electrical contacts 128a, 128b to the weld seams 122a, 122b generally results in a high current density that generally provides a corresponding high welding efficiency along with a small heat affected zone. As shown in Figures 8A and 8B, the electrical contacts 128a, 128b may be placed to concentrate the current along the surfaces of the sheets 112 that will subsequently be adjacent. The current travels from one electrical contact to the other in the illustrated pair to generate heat with the resulting electrical resistance at the edges 124a, 124b of the sheets 112 and at the outer surfaces of the intermediate portions 126a, 126b of the sheets 112. The heat is generally concentrated where these portions of the sheets 112 will subsequently be joined.

[0035] As further shown in Figures 8A and 8B, the electrical contacts 128a, 128b may include spring-loaded contact plates that are biased toward and against the desired portion of the sheet 112. The tip portions of the spring-loaded contact plates may directly engage the sheet 112 to slide along the outer surface of the sheet 112 as the sheet moves through the welding station. Also, with the use of galvanized sheet metal, when the outer surface of the sheet 112 is heated by the electrical contacts 128a, 128b to the desired welding temperature, the galvanized coating is at least partially burned off or vaporized at the edge 124a and middle portion 126a of the sheet 112 to form zinc oxide gas, which is subsequently released by the gap between the surfaces to be joined. The high frequency current supplied to the opposing portions of the seam may be selected or configured to heat the outer surfaces of the edge 124a, 124b and middle portion 126a, 126b of the sheet 112 when the joining surfaces of the sheets come into contact to reach the desired welding temperature for the particular material and sheet thickness. In addition to providing a desired weld temperature at the weld seam 122a, 122b, the RF current may also be selected or configured in conjunction with the sheet speed to reach a sufficient temperature at the edges 124a, 124b and middle portions 126a, 126b for a sufficient time to burn off or vaporize the galvanized coating due to the mating surfaces contacting. For example, the RF current may be between 80KHz and 800KHz, or between 150KHz and 800KHz, or between 150KHz and 450KHz, or approximately 350KHz.

[0036] 8, immediately after passing the electrical contacts 128a, 128b, the sheet 112 enters one or more closing press rolls which simultaneously press together the edges 124a, 124b and the intermediate portions 126a, 126b of the sheet 112 to close the weld seams 122a, 122b. As a result, the tubular portions 118, 120 are simultaneously closed at the weld seams 122a, 122b formed continuously between the edges 124a, 124b and the intermediate portions 126a, 126b of the sheet 112 along the length of the reinforcing beam 110 to forge lap joints at the weld seams 122a, 122b located at the opposite ends of the common central wall 132. The pressure applied by one or more closing press rolls may reduce or eliminate the entrapment of zinc oxide gas in or near the resulting weld, so as to form a solid weld that is generally free of zinc inclusions or other defects associated with zinc oxide gas generated in the welding process of galvanized sheet metal. Additionally, the solid weld formed by radio frequency contact welding may have a narrow heat affected zone, such as on the order of 1 mm to 2 mm.

[0037] 9-10A, an additional example of a galvanized multi-tubular reinforcement beam 210 having two adjacent tubular portions 218, 220 that also share a common central wall 232 that longitudinally divides the tubular portions 218, 220 along the length of the beam 210 is shown. The beam 210 is similar to the beam 10 shown in FIG. 3A, except that the second weld seam 222b of the reinforcement beam 210 is substantially T-shaped. Specifically, the weld seam 222b may be referred to as a T-joint or T-shaped joint. Here, the end portion 223 of the sheet 212 having the edge 224b is inwardly inset by the S-shaped curve 225 of the rear wall 240 and is oriented generally parallel to the planar extent of the rear wall 240 to extend toward the central wall 232. In such an orientation, the end portion 223 joins the joining intermediate portion 226b of the central wall 232 in a generally perpendicular configuration. The S-curve 225 and the resulting inset edge portion 223 provide a rib 247 on the rear surface of the beam 210 to increase stiffness along the rear surface of the beam 210 .

[0038] The weld seams 222a, 222b of the beam 210 shown in Figures 9-10A may be formed in a radio frequency welding process by passing the formed sheet against a radio frequency electrical resistance weld contact before entering closing press rolls which press the respective edges 224a, 224b and intermediate portions 226a, 226b of the sheet together to close the respective weld seams 222a, 222b. The forming and welding process for the beam shown in Figures 9-10A may be substantially the same as that described above with reference to the beam 10 shown in Figures 1-6A.

[0039] The tubular portions 218, 220 of the beam 210 as oriented in Figures 9-10A also have front walls 234, 236 and rear walls 238, 240, respectively, that are generally aligned with one another. The upper tubular portion 218 comprises the upper wall 242 of the beam 210. The lower tubular portion 220 comprises the lower wall 244 of the beam 210. The front walls 234, 236 of the tubular portions 218, 220 are substantially aligned in a common plane with one another to form an outwardly facing or impact surface of the beam 210 when used as a bumper reinforcement beam. Similarly, the rear walls 238, 240 are generally planarly aligned with one another and substantially parallel to the front walls 234, 236. Additionally, the upper and lower walls 242, 244 are substantially parallel to one another and to the central wall 232, and are generally perpendicular to the front and rear walls 234, 236, 238, 240. The corners between the walls of the tubular portions 218 , 220 of the beam 210 have a curvature that is generally defined by the material type and thickness of the metal sheet 212 .

[0040] As further shown in Figures 9-10A, the front walls 234, 236 of the tubular portions 218, 220 each include a stiffening rib 246 that protrudes into the interior volume of the respective tubular portion to stiffen the front impact face of the stiffening beam 210. The stiffening rib 246 shown has a width diameter that is about 10%-40% of the width of the corresponding wall section (or more preferably about 20%-30% of the width of the corresponding wall section) and has a depth that is approximately equal to the width diameter. The bottom of the stiffening rib 246 shown is semicircular in shape. Nevertheless, it is contemplated that the depth and size of the stiffening rib may be made shallower, deeper, wider, narrower, flat-bottomed, or otherwise modified to meet the particular requirements of the beam.

[0041] As shown in Figures 11A-23B, further embodiments of reinforcing beams are shown having two adjacent tubular portions that also share a common central wall that divides the tubular portions longitudinally along the length of the respective beams. The tubular portions of these additional embodiments also each have a front wall and a rear wall that are generally aligned in a common plane with each other to form the outward facing or impact face of the beam when used as a bumper reinforcing beam. Similarly, the rear walls of these additional embodiments are generally planarly aligned with each other and are substantially parallel to the front wall. These additional embodiments each have at least one weld seam that is a T-joint or T-shaped joint, where the edge portions of the sheets join in a configuration generally perpendicular to the joining intermediate portions of the sheets. The weld seams of these additional beams can be formed with a radio frequency welding process, such as the radio frequency contact welding process described above and with reference to the beams shown in Figures 1-6.

[0042] In another implementation of the reinforcing beam forming process disclosed herein, the weld seam may be formed in a high frequency induction welding process by passing the formed sheet through an induction coil immediately prior to entering a closing press roll that closes the weld seam. The induction coil heats the outer surfaces of the two opposing portions of the weld seam with high frequency current to the appropriate welding temperature. The two heated opposing portions are then forced together by the closing press roll to form a solid weld. Skin and proximity effects from the application of high frequency current to the partially formed beam generate heat at the outer surfaces of the edges and middle portions of the sheet where these portions of the sheet bond together. When the outer surfaces of the sheet are heated by the induction coil, the galvanized coating is at least partially burned off at the edges and middle portions of the sheet to form zinc oxide gases. These zinc oxide gases generally do not interfere with the quality and consistency of the solid weld formed by the closing press rolls. The pressure applied by the closing press rolls can reduce or eliminate the entrapment of zinc oxide gas within or near the resulting weld to form a solid weld that is generally free of process generated zinc inclusions or other defects associated with zinc oxide gas.

[0043] In a further implementation, a method of continuously forming a galvanized reinforcing beam includes the steps of: (a) unwinding a roll of galvanized metal sheet in a generally horizontal plane; (b) roll forming the metal sheet through a set of multiple roll stations to form a tubular shape in which edge sections of the metal sheet approximately contact a middle section of the metal sheet; (c) heating outer surfaces of the edge sections of the metal sheet and the middle section of the metal sheet to a desired welding temperature with high frequency current supplied to the metal sheet by a pair of electrical contacts, wherein the galvanized coating on the metal sheet is at least partially burned off at the heated outer surfaces; and (d) forming a solid weld on the heated outer surfaces of the edge sections and the middle section of the metal sheet by pressing the outer surfaces together with a closing press roll, wherein the solid weld is continuously formed to close a seam of the tubular shape of the reinforcing beam. Also, the second edge of the metal sheet may be welded at a second forge weld in the wall of the tubular portion of the reinforcing beam to surround a second tubular portion extending along the length of the reinforcing beam. For example, the second forge weld may be formed by roll forming the second edge of the galvanized metal sheet closer to the wall of the tubular portion after the first tubular portion is closed at the first forge weld to form a second forge weld at the second pair of electrical contacts. The first and second tubular portions may share a common central wall of the reinforcing beam, whereby the forge welds are located at opposing ends of the common central wall. Additionally, the metal sheet may be unrolled longitudinally at a generally constant speed, roll formed, and welded.

[0044] For purposes of this disclosure, the term "coupled" (in all its forms, such as coupled, coupled, connected, etc.) generally means the joining of two components directly or indirectly to one another. Such joining may be stationary or movable in nature; may be achieved by the two components and any additional intermediate members integrally formed with one another or with the two components as a single unitary body; and may be permanent in nature or removable or releasable in nature, unless otherwise specified.

[0045] The articles "a," "an," and "the" are intended to mean the presence of one or more of the elements in the preceding description. The terms "comprise," "include," and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements. It is further understood that references to "one embodiment" or "embodiments" of the present disclosure are not intended to be interpreted as excluding the existence of additional implementations that also incorporate the recited features. It is also understood that the specific devices and processes illustrated in the accompanying drawings and described herein are merely exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.

[0046] Any numerical values, percentages, ratios, or other values ​​described herein are intended to include those values ​​and other values ​​that would be understood by a person skilled in the art to be "about," "approximately," or "substantially" the described value that are encompassed by the implementations of the present disclosure. Thus, the described values ​​should be interpreted broadly enough to include values ​​that are at least sufficiently close to the described value to perform the desired function or achieve the desired result. The described values ​​include at least expected variations in suitable manufacturing or production processes, and may include values ​​within 5%, 1%, 0.1%, or 0.01% of the described value. Also, the terms "approximately," "about," and "substantially" as used herein refer to an amount close to the described amount that still performs the desired function or still achieves the desired result. For example, the terms "approximately," "about," and "substantially" may refer to an amount that is within less than 5%, less than 1%, less than 0.1%, and less than 0.01% of the described amount.

[0047] Additionally, it should be understood that any directions or frames of reference in the preceding description are merely relative directions or movements. For example, the terms "up," "down," "right," "left," "rear," "front," "vertical," "horizontal," "interior," "exterior," and derivatives thereof, are intended to refer to the directions shown in Figure 1. However, it is understood that various alternative orientations may be provided, unless expressly specified to the contrary.

[0048] Variations and modifications to the specifically described embodiments may be made without departing from the principles of the invention, which are intended to be limited only by the scope of the appended claims as interpreted in accordance with the principles of patent law. The present disclosure has been described in an illustrative manner. It will be understood that the terms used are intended to be within the nature of the described words, rather than being limiting. Many modifications and variations of the present disclosure are possible in light of the above teachings. The present disclosure may be practiced otherwise than as specifically described.

Claims

1. 1. A reinforcement beam for an automotive component, comprising: a sheet metal roll formed to have a pair of tubular portions sharing a common central wall and extending along the length of said reinforcing beam; a solid forge weld formed in-line with said roll-formed metal sheet between an edge of said metal sheet and an intermediate portion of said metal sheet to close a seam encircling one of said pair of tubular portions at an end of said common central wall; the joint formed by the solid weld extends continuously along the length of the reinforcing beam; A reinforcing beam, wherein prior to forming the solid weld, the edges of the metal sheet and an outer surface of the intermediate portion of the metal sheet are heated by electrical resistance to a desired weld temperature.

2. The reinforcement beam of claim 1 , wherein the solid forge weld has a narrow heat affected zone of 1 mm to 2 mm in width.

3. 3. A reinforcing beam as claimed in claim 1 or 2, wherein a second edge of the metal sheet is welded with a second forge weld at a second end of the common central wall of the reinforcing beam to surround the other of the pair of tubular portions extending along the length of the reinforcing beam.

4. 3. A reinforcing beam as claimed in claim 1 or 2, including a front impact surface defined by front walls of said pair of tubular portions.

5. 5. The stiffening beam of claim 4, wherein said front wall of at least one of said pair of tubular portions includes a stiffening rib projecting into an interior volume of said respective tubular portion for stiffening said front impact face.

6. 3. The reinforcing beam of claim 1 or 2, wherein the solid weld is formed by heat generated by the electrical resistance of high frequency current supplied by an electric resistance welding junction and closing press rolls pressing the heated surfaces of the metal sheets together.

7. 3. The reinforcing beam of claim 1 or 2, wherein the metal sheets comprise high strength steel and the desired welding temperature is below the melting temperature of the high strength steel of the metal sheets.

8. the metal sheet includes a galvanized coating, the thickness of the metal sheet is between 1 mm and 1.5 mm; the galvanized coating is electroplated to have a generally uniform thickness of less than 0.2 mm; 8. The reinforcement beam of claim 7, wherein the desired welding temperature burns off the galvanized coating on the metal sheet at the exterior surface prior to forming the solid weld.

9. 1. A reinforcement beam for an automotive component, comprising: a galvanized metal sheet roll-formed to have a tubular portion extending along the length of the reinforcing beam; a solid forge weld formed between an edge of the galvanized metal sheet and an intermediate portion of the galvanized metal sheet to close a seam extending along the tubular portion of the reinforcing beam; prior to forming the solid weld, the edges of the galvanized metal sheet and an outer surface of the intermediate portion of the galvanized metal sheet are heated to a desired welding temperature; A reinforced beam, wherein the desired welding temperature burns off the galvanized coating on the galvanized metal sheet at the exterior surface before forming the solid weld that is substantially free of zinc inclusions.

10. 10. The reinforcing beam of claim 9, wherein said solid forge weld extends continuously along the length of said reinforcing beam to surround an interior of said tubular portion of said reinforcing beam.

11. 10. The reinforced beam of claim 9, wherein the edge and intermediate portions of the galvanized metal sheet form a T-joint at the solid forge weld.

12. 10. The reinforcing beam of claim 9, wherein a second edge of the galvanized metal sheet is welded at a second forge weld in a wall of the tubular portion of the reinforcing beam to surround a second tubular portion extending along a length of the reinforcing beam.

13. The reinforcing beam of claim 12 , wherein said tubular portions share a common central wall of said reinforcing beam.

14. The reinforcing beam of claim 13 , wherein the forge welds are located at opposing ends of the common central wall.

15. 15. The reinforcing beam of claim 14 including a front impact surface defined by front walls of said tubular portions disposed in planar alignment with one another.

16. 10. The reinforced beam of claim 9, wherein the galvanized metal sheet comprises high strength steel, and the desired welding temperature is below a melting temperature of the high strength steel of the galvanized metal sheet.

17. The thickness of the galvanized metal sheet is between 1 mm and 1.5 mm; 10. The reinforced beam of claim 9, wherein the galvanized coating is electroplated to have a generally uniform thickness of less than 5 mils.

18. 1. A method for continuously forming a galvanized reinforcement beam, comprising: unwinding a roll of galvanized metal sheet in a generally horizontal plane; roll forming the metal sheet through a set of multiple rolling stations to form a tubular shape in which edge sections of the metal sheet generally contact an intermediate section of the metal sheet; heating the edge sections of the metal sheet and the outer surfaces of the middle section of the metal sheet to a desired welding temperature with high frequency current supplied to the metal sheet by a pair of electrical contacts, wherein a galvanized coating on the metal sheet is at least partially burned off at the heated outer surfaces; forming solid welds on the heated outer surfaces of the edge and middle sections of the metal sheet by pressing the outer surfaces together with a closing press roll, the solid welds being continuously formed to close the seam of the tubular shape of the reinforcing beam; The method includes:

19. 20. The method of claim 18, wherein the metal sheet is unwound longitudinally at a generally constant speed, roll formed, and welded.

20. 20. The method of claim 18 or 19, wherein the tubular shape defines a first tubular portion, and a second edge of the metal sheet is welded with a second forge weld in a wall of the first tubular portion of the reinforcing beam to surround a second tubular portion extending along a length of the reinforcing beam.

21. 21. The method of claim 20, wherein the reinforcing beam includes a front impact surface defined by front walls of the first and second tubular portions.

22. 22. The method of claim 21, wherein the front wall of the first or second tubular portion includes a stiffening rib protruding into an interior volume of the respective tubular portion to stiffen the front impact surface.

23. The method according to claim 18 or 19, wherein the solid forge weld has a narrow heat affected zone with a width of 1 mm to 2 mm.

24. 20. The method of claim 18 or 19, wherein the solid weld is formed by heat generated by the electrical resistance of high frequency current supplied by an electric resistance welding junction and closing press rolls pressing heated surfaces of the metal sheets together.

25. 20. The method of claim 18 or 19, wherein the metal sheet comprises high strength steel and the desired welding temperature is below the melting temperature of the high strength steel of the metal sheet.

26. 20. The method of claim 18 or 19, wherein the metal sheet has a thickness of 1 mm to 1.5 mm, the galvanized coating is electroplated to have a generally uniform thickness of less than 0.2 mm, and the desired welding temperature burns off the galvanized coating on the metal sheet at the outer surface before forming the solid weld.

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