INTRODUCTION
The present disclosure relates to a method for providing improved formability of a stamped component.
Stamping is a manufacturing process used for forming specifically shaped components from work-piece blanks. Stamping generally includes such forming operations as punching, blanking, embossing, bending, flanging, and coining. The process of stamping typically employs a machine press to shape or cut the work-piece blank by deforming it with a die.
The stamping process could be a single stage operation where every stroke of the press produces the desired form on the work-piece, or may occur through a series of stages. Stamping of a work-piece into a desired shape is frequently limited by the ability of the work-piece to withstand deformation without developing splits and tears. Such concerns are further aggravated when the work-piece blank is generated from a high-strength, lower ductility material.
SUMMARY
A method of shaping a component having a component contour includes providing a work-piece blank from a formable material. The method also includes forming a first stage of the component contour in the work-piece blank, such that the first stage of the component contour is bordered by an outer region of material of the work-piece blank. The method additionally includes forming a stake bead in the outer region of material following the forming of the first stage of the component contour, wherein the stake bead has an asymmetrical shape when viewed in a cross-sectional plane. The method furthermore includes forming a second stage of the component contour in the work-piece blank, wherein the asymmetrical shape of the stake bead is configured to limit flow of the work-piece blank material into the second stage of the component contour from the outer region of material to thereby limit an amount of springback and a resultant twist and/or curl of the component contour in the stamped component.
The component contour may include a wall arranged along a first axis. The forming of the second stage of the component contour may include stretching the work-piece blank along the first axis and thereby forming the wall. Additionally, the outer region of material may be arranged substantially in a plane perpendicular to the first axis.
The asymmetrical shape of the stake bead may facilitate the stretching of the work-piece blank to thereby form the wall along the first axis without localized compression of the material in the second stage of the component contour. At least a part of the stretching of the work-piece blank used to form the wall extends into and stops in the stake bead.
When viewed in the cross-sectional plane, the forming of the asymmetrical shape of the stake bead may include forming a first radius and a fourth radius in transitions between the outer region of the material and the bead and a peak of the bead defined by a second radius and a third radius. The forming of the asymmetrical shape of the stake bead may also include forming the second radius between the first radius and the third radius, and the third radius is arranged between the second radius and the fourth radius. Thus formed first radius may be at least two times greater than the formed fourth radius.
The method of stamping the component may also include arranging the fourth radius between the first radius and the wall of the component contour, and arranging the third radius between the wall of the component contour and the second radius.
The method of stamping the component may additionally include arranging the first radius between the fourth radius and the wall of the component contour, and arranging the second radius between the wall of the component contour and the third radius.
When viewed in the cross-sectional plane, the forming of the stake bead in the outer region of material may also include forming a flat section between the second radius and the third radius.
The forming of the stake bead in the outer region of material may alternatively include forming an uninterrupted stake bead around a perimeter of the component contour.
The forming of the stake bead in the outer region of material may include forming a localized substantially straight section of the stake bead not extending fully around a perimeter of the component contour.
The forming of the stake bead in the outer region of material may include tapering the localized substantially straight section of the stake bead down into the outer region of material without following a curve around the component contour.
The material of the work-piece blank may be a ductile advanced high-strength steel (AHSS) having a tensile strength of 1000-1200 MPa.
Alternatively, the material of the work-piece blank may be an advanced high-strength steel (AHSS) having a tensile strength of around 1500 MPa or greater.
The component may be a structural reinforcement for a motor vehicle body structure.
An additional embodiment of the present disclosure is a stamping tooling for forming from a work-piece blank a component having a component contour. The stamping tooling is configured to form a first stage of the component contour in the work-piece blank, such that the first stage of the component contour is bordered by an outer region of material of the work-piece blank, and form a second stage of the component contour in the work-piece blank following the forming of the first stage of the component contour. The stamping tooling includes a stake bead profile configured to form in the outer region of material, after completion of the first stage of the component contour and during forming of the second stage of the component contour, a stake bead having the above-described asymmetrical shape when viewed in a cross-sectional plane. As above, the asymmetrical shape of the stake bead is configured to limit flow of work-piece blank material into the second stage of the component contour from the outer region of material to thereby limit an amount of springback and a resultant at least one of twist and curl of the stamped component contour.
The above features and advantages, and other features and advantages of the present disclosure, will be readily apparent from the following detailed description of the embodiment(s) and best mode(s) for carrying out the described disclosure when taken in connection with the accompanying drawings and appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic illustration of a component contour being formed from a representative work-piece blank using stamping tooling.
FIG. 2 is a schematic cross-sectional illustration of a formed first stage of the component contour shown in FIG. 1, and depicting an outer region of the work-piece blank.
FIG. 3 is a schematic cross-sectional illustration of a formed second stage of the component contour, having an asymmetrical shape stake bead formed in the outer region of the work-piece blank for controlling a flow of the work-piece blank material.
FIG. 4 is a schematic cross-sectional illustration of one embodiment of the asymmetrical shape stake bead.
FIG. 5 is a schematic cross-sectional illustration of another embodiment of the asymmetrical shape stake bead.
FIG. 6 is a schematic perspective view of the component contour depicting various distinct embodiments of the asymmetrical shape stake bead.
FIG. 7 is a flow chart illustrating a method of forming the component contour, employing the embodiments of the asymmetrical shape stake bead shown in FIGS. 1-6.
DETAILED DESCRIPTION
Referring to the drawings in which like elements are identified with identical numerals throughout, FIGS. 1-3 illustrate, in detail, processing, such as stamping, of a work-piece blank 10. Such work-piece blanks 10 are frequently used in manufacturing processes, such as metal stamping, to form specifically shaped components. Typically such components are formed from work-piece blanks 10 in a stamping press 11 using stamping tooling such as a die 11A and a punch 11B, as shown in FIG. 1. Each work-piece blank 10 is typically a pre-cut piece of formable material, for example sheet metal, such as cold rolled steel. Specifically, a suitable material of the subject work-piece blank 10 may be Advanced High-Strength Steel (AHSS).
AHSS is a specific variety of alloyed steel that is both strong and ductile. There are several commercially available grades of AHSS. One such grade of AHSS is dual-phase steel, which is heat treated to contain both a ferritic and martensitic microstructure to produce a formable, high strength steel. Another type of AHSS is Transformation Induced Plasticity (TRIP) steel, which involves special alloying and heat treatments to stabilize amounts of austenite at room temperature in normally austenite-free low-alloy ferritic steels. By applying strain to the TRIP steel, the austenite is caused to undergo a phase transition to martensite without addition of heat. Yet another variant of AHSS is Twinning Induced Plasticity (TWIP) steel, which uses a specific type of strain to increase the effectiveness of work hardening on the alloy. AHSS is especially beneficial for structural components used in motor vehicles. AHSS permits structural components of motor vehicles to maintain required strength while using a smaller amount of material.
Dual-phase steels offer a beneficial combination of strength and drawability or formability as a result of their microstructure, in which a hard martensitic or bainitic phase is dispersed in a soft ferritic matrix. Dual-phase steels also have high strain hardenability. High strain hardenability, in turn, gives dual-phase steels good strain redistribution capacity and drawability, as well as finished part mechanical properties, including yield strength, that are superior to those of the initial work-piece, for example the work-piece blank 10. Additionally, the composition and processing of dual-phase steels are specifically designed to promote a significant increase in yield strength during low-temperature heat treatment, such as paint baking or bake hardening (BH).
High finished-part mechanical strength lends dual-phase steels excellent fatigue strength and good energy absorption capacity, making these steels suitable for use in structural components and reinforcements. The strain hardening capacity of dual-phase steels combined with a strong bake hardening effect gives them excellent potential for reducing the weight of structural components. Given their high energy absorption capacity and fatigue strength, cold rolled dual-phase steels are particularly well suited for automotive structural components, such as floor pans, longitudinal beams, cross members and reinforcements.
A ductile AHSS may have a tensile strength of 1000-1200 MPa, and may be used for high-strength structural parts responsible for energy management, especially in situations when formability requirements are higher than offered by equivalent grades of conventional high-strength low-alloy (HSLA) steel. In applications where ductility is not as critical as the ultimate strength, components may be formed using AHSS having a tensile strength of around 1500 MPa or greater. Alternatively, especially in components having different key requirements, the material of the work-piece blank 10 may be Aluminum or Magnesium alloys, or mild steel.
To produce a stamped component 12 having a desired final shape or contour 12A, the work-piece blank 10 should be provided from a material 14, for example the AHSS described above, formable in the stamping press 11, as shown in FIG. 1. For ease of description and viewing, FIGS. 2-6 depict the stamped component 12 turned upside down relative to FIG. 1. As shown in FIG. 2, an initial or first stage 12-1 of the component contour 12A is formed from the work-piece blank 10. Specifically, the first stage 12-1 of the component contour 12A is to be formed such that the first stage of the contour becomes bordered or substantially surrounded by an outer region 16 of material 14 of the work-piece blank 10.
As shown in FIG. 3, following the generation of the first stage 12-1 of the component contour 12A, a stake bead 18 is formed in the outer region 16 of the material 14 during a second stage 12-2 of the component contour 12A. The second stage 12-2 of the component contour 12A may be formed in the work-piece blank 10 as either a final or an intermediate stage of the stamping process envisioned by the present disclosure. Furthermore, the first and second stages 12-1, 12-2 may be consecutive or non-consecutive steps in the single stamping operation, i.e., using a single set of die 11A and punch 11B, or individual draws performed via a separate set of die 11A and punch 11B for each respective stage.
A geometry or profile 19 of the stake bead 18 is intended to be machined into the stamping tooling, i.e., on the die 11A and on the punch 11B. The profile 19 of the stake bead 18 is arranged in an area of the stamping tooling such that the material 14 of the work-piece blank 10 is not deformed by the profile 19 until very near the end of the punch 11B forming process. Accordingly, the stake bead 18 is specifically configured to generate minimal to zero force on the work-piece blank 10 until forming of the second stage 12-2 of the component contour 12A commences. The stake bead 18 has an intentionally asymmetrical shape 20 (shown in FIGS. 3-5) when viewed in a cross-sectional plane P1 (shown in FIG. 1). Significantly, the profile 19 in the stamping tooling is configured to form the asymmetrical shape 20 of the stake bead 18 in the outer region 16 of material 14 after completion of the first stage 12-1 of the component contour 12A and during forming of the second stage 12-2 of the component contour. The stake bead profile 19 may be machined into the die 11A and the punch 11B, such that each of the die and punch reflect the asymmetrical shape 20. Alternatively, the stake bead profile 19 may be machined only into the punch 11B for material 14 to conform thereto and thereby determine the asymmetrical shape 20, while the die 11A only serves to receive the material 14 driven by the punch.
The asymmetrical shape 20 of the stake bead 18 is formed into the work-piece blank material 14 by the profile 19 to control and/or limit draw or flow of the material 14 of the work-piece blank material during the second stage 12-2 of the component contour 12A from the outer region 16 of the material that borders the second stage of the contour. As a result of controlling and/or limiting the flow of work-piece blank material 14 into the second stage 12-2 of the component contour 12A from the outer region 16 of the material, a magnitude of springback, i.e., the capacity of the shaped material to revert to its initial form, designated in FIG. 3 by angle θ1, and the resultant twist and/or curl of the stamped component contour 12A is also limited. “Springback” is herein defined as the result of unloading the forces and moments exerted on the work-piece blank 10 at the end of forming when the stamping press 11 has reached a fully closed position, i.e., the die 11A and the punch 11B have fully compressed the work-piece blank therebetween. As such, the magnitude of the springback is the incapacity or inability of the shaped material to conform to the shape of the tooling die 11A and punch 11B.
Additionally, “twist” refers to distortion of the overall shape of the stamped component contour 12A shown in FIGS. 1 and 6. On the other hand, “curl” is associated with the curvature that may spontaneously appear in a wall 22 of the stamped component contour 12A shown in FIGS. 2-5. Specifically, the asymmetrical shape 20 of the stake bead 18 imparts a stretch into, but no compression, within the material 14 of the second stage 12-2 of the component contour 12A to thereby generate the finished stamped component 12. As a result of controlling and/or limiting the flow of work-piece blank material 14 during the forming of the second stage 12-2 of the component contour 12A from the outer region 16, the magnitude of the springback angle θ1 may be minimized or reduced into a range of 0 to 1.5 degrees.
The stamped component contour 12A may include the wall 22 referenced above. As shown, the wall 22 is arranged generally along or at a sharp angle of a first axis Y1 that is disposed within or parallel to the plane P1. The forming of the second stage 12-2 of the component contour 12A via the stamping tooling may include, at least in part, stretching the work-piece blank 10 generally along the first axis Y1 to thereby form the wall 22. As shown in FIGS. 2 and 3, the wall 22 may have a springback angle θ2 with respect to the first axis Y1. During the forming of the second stage 12-2 of the component contour 12A, at least a section of the outer region 16 of the material 14 may be arranged in a plane P2 (shown in FIG. 1) that is transverse, such as either at a slant or approaching a right angle, i.e., substantially perpendicular, to the plane P1 and the first axis Y1.
The asymmetrical shape 20 of the stake bead 18 is intended to facilitate the stretching of the work-piece blank 10 to thereby form the wall 22 along the first axis Y1 without localized compression of the material 14 in the second stage 12-2 of the component contour 12A. The asymmetrical shape 20 of the stake bead 18 additionally controls and/or limits the flow of work-piece blank material 14 from the outer region 16 and imparts a controlled stretch of the wall 22 during the second stage 12-2 of the component contour 12A. As a result of such controlling and/or limiting the flow of work-piece blank material 14 during the forming of the second stage 12-2 of the component contour 12A, the magnitude of the springback angle θ2 may be minimized or reduced into a range of 3 to 5 degrees.
During forming of the second stage 12-2 of the component contour 12A via the stamping tooling, at least part of the stretching of the work-piece blank 10 for forming the wall 22 may extend into and end within the stake bead 18, i.e., the stretching of the work-piece blank would not extend beyond the stake bead when viewed in the cross-sectional plane P1. The first stage 12-1 of the component contour 12A may include an initial stage of the formed wall 22 having a length l1, shown in FIG. 2. The length l1 of the initial stage of the wall 22 may be significantly shorter than a length l2, shown in FIG. 2, of the wall 22 of the second stage 12-2 of the component contour 12A. Accordingly, the longer length €2 of the wall 22 may be generated during forming of the second stage 12-2 of the component contour 12A, and may be the fully stretched length of the wall 22 in the final stamped component 12.
When viewed in the cross-sectional plane P1, the forming of the asymmetrical shape 20 of the stake bead 18 via the stake bead profile 19 may include forming a peak 18A of the stake bead, along with a first radius R1 and a fourth radius R4 in transitions between substantially straight sections of the stake bead, and a second radius R2 and a third radius R3 defining the peak 18A of the bead, as shown in FIGS. 4 and 5. Specifically, the first radius R1 and the fourth radius R4 are formed in the transitional areas A1 and A2, between material of the outer region 16 and the bead 18 formed therein, while the second and third radii R2, R3 are formed at the peak of the stake bead 18. Furthermore, the first and fourth radii R1 and R4 may be purposefully selected to be of dissimilar magnitude and the first radius R1 is measurably greater than the fourth radius R4. Specifically, the first radius R1 may be at least two times greater than the fourth radius R4. In such an embodiment, the dissimilar magnitudes of the first and fourth radii R1, R4 are intended to increase the draw of material 14 from the side of the stake bead 18 proximate the first radius R1 and decrease the draw of material from the side of the stake bead proximate the fourth radius R4 to thereby form the asymmetric geometry of the stake bead. Furthermore, the comparatively larger first radius R1 is intended to reduce the severity of the forming condition in the stake bead 18, i.e., reduce localized strain in the stake bead, in order to avoid tearing the material therein.
As shown in FIG. 4, as formed via the stake bead profile 19 of the stamping tooling, the fourth radius R4 may be arranged, i.e., formed in the outer region 16 of the material 14, between the first radius R1 and the wall 22 of the component contour 12A. In such an embodiment, the second radius R2 would be arranged between the first radius R1 and the third radius R3, while the third radius R3 would be arranged between the second radius R2 and the fourth radius R4. Furthermore, in the subject embodiment, the third radius R3 would be arranged closer to the wall 22 as compared to the position of the second radius R2. In other words, in the embodiment of FIG. 4 the third radius R3 is arranged between the wall of the component contour and the second radius R2.
Alternatively, when formed via the stake bead profile 19 of the stamping tooling, as shown in FIG. 5, the first radius R1 may be arranged between the fourth radius R4 and the wall 22. In such an embodiment, the second radius R2 would similarly be arranged between the first radius R1 and the third radius R3, and the third radius R3 would be arranged between the second radius R2 and the fourth radius R4. However, in the embodiment of FIG. 5, the second radius R2 would be arranged closer to the wall 22 as compared to the position of the third radius R3. In other words, in the embodiment of FIG. 5 the second radius R2 is arranged between the wall of the component contour and the third radius R3.
In each of the embodiments of FIGS. 4 and 5, the fourth radius R4 may be relatively small to prevent any material 14 from flowing across the fourth radius before the end of forming the second stage 12-2 of the component contour 12A. The magnitude of the first radius R1 may be larger than the fourth radius R4 to facilitate the flow of material 14 across the first radius to provide sufficient amount of material for forming the stake bead 18. Additionally, the larger first radius R1 relative to the second fourth radius R4 facilitates a reduced or minimized amount of stretch of the material 14 within the stake bead 18 to avoid tearing the material therein.
The positioning of the first and second radii R1 and R4 relative to each other and to the wall 22, as depicted in FIGS. 4 and 5, is intended to facilitate the stretching of the work-piece blank 10 either in a region of the material 14 between the wall and the stake bead 18, or both in the region between the wall and the stake bead 18 and within the actual stake bead 18. Specifically, in the embodiment of FIG. 4, when the second, smaller radius R4 is arranged between the first, larger radius R1 and the wall 22 of the component contour 12A, the stretching of the work-piece blank 10 into the wall comes substantially from the material 14 already within the wall at the start of forming the second stage 12-2 of the component contour 12A. Additionally, in the embodiment of FIG. 4, the material 14 to form the stake bead 18 at the start of forming of the second stage 12-2 of the component contour 12A comes from a combination of the material already within the stake bead and the material from the outer region 16 beyond or outside of the first radius R1.
On the other hand, in the embodiment of FIG. 5, when the first, larger radius R1 is arranged between the second, smaller radius R4 and the wall 22 of the component contour 12A, the flow of material 14 from the outer region 16 into the stake bead 18 stops. From that point, the stretching of the work-piece blank 10 into the component contour 12-2 is shared between forming the wall 22 and forming the stake bead 18 itself. Additionally, the net flow of the material 14 from the stake bead 18 area to the wall 22 area or vice versa, depends primarily on the relative depth of the stake bead and the remaining distance of punch 11B travel, and secondarily on the various details and geometry of both subject areas.
In general, each of the embodiments of FIG. 4 and FIG. 5 is intended to limit the flow of material 14 from the outer region 16 into the component contour 12-2. Specifically, the separate embodiments of the stake bead 18 shown in FIGS. 4 and 5 are each configured to limit the flow of material 14 across a radius R5 at the bottom of the wall 22 into the wall itself. As shown in FIGS. 4 and 5, both embodiments are intended to stop flow of material 14 across radius R4, which is arranged in different locations in the two embodiments. The embodiment in FIG. 4 is generally intended to be used if the material 14 of the work-piece blank 10 is found to split or tear within a conventional symmetrical stake bead (not shown). In this situation, increasing the R1 radius or increasing an angle θ3 of the slope of the asymmetrical stake bead 18 will cause more draw of the material 14 from the outer region 16, thereby reducing the tendency for splitting, while having a second order effect on the effectiveness of press lock-out condition at the inside radius R4.
Conversely, the alternative embodiment in FIG. 5 is generally intended to be used when the material 14 within the conventional symmetric stake bead 18 may be formed without splitting, but splits are observed within the component contour 12-2. In such a case, prior to considering changes to the component contour 12-2, an increase in the radius R1 or the angle θ3 of the slope of the asymmetrical stake bead 18 will cause a reduction in the tension within the component contour 12-2. Specifically, an increase in the radius R1 or the angle θ3 of the slope of the asymmetrical stake bead 18 may permit a limited amount of draw of material 14 from the stake bead area at the start of the second stage 12-2 of the component contour 12A, thus reducing the tendency for splitting, while having a second order effect on the effectiveness of the lock out condition at the outside radius R4.
In either embodiment shown respectively in FIGS. 4 and 5, an angle θ4 defines a slope of the more upright or steeper side of the stake bead 18. Accordingly, in each of the embodiments shown in FIGS. 4 and 5, the angle θ4 is greater than the angle θ3. Although not shown, alternatively, the radius R1 may be substantially equivalent to the radius R4. However, even in such an embodiment, the angle θ4 is intended to be comparatively greater than the angle θ3. The comparative ratio of the angle θ4 to the angle θ3 may be greater than 2:1. To achieve a particular angle θ3 of the requisite slope that the material 14 takes in the stake bead 18 does not have to be specifically machined into the die 11A and the opposing punch 11B. Instead, to achieve a desired angle θ3, the center of the stake bead 18 may be machined in the die 11A or in the punch 11B off center from the cavity on the opposing tool. Overall, the comparative relationship between magnitudes of the radii R1, R2, R3, and R4 in the formed stake bead 18 may be expressed according to the following relationship:
R1≥R2≥R3≥R4
When viewed in the cross-sectional plane P1, when formed via the stake bead profile 19 of the stamping tooling, the stake bead 18 may additionally include a flat section 24 arranged or formed at the peak 18A of the stake bead between the second radius R2 and the third radius R3. In such an embodiment, the stretching of the wall 22 may come from the flat section 24, especially where the larger radius R1 is arranged between the fourth radius R4 and the wall in the embodiment of FIG. 5. The selection of the embodiment of the stake bead 18 may be guided by the selected material 14 for stamped component 12. Specifically, the embodiment of FIG. 4 would be more beneficial for the more ductile AHSS, such as having tensile strength in the region of 100-1200 MPa, while the embodiment of FIG. 5 would be more appropriate for the less ductile AHSS having tensile strength of 1500 MPa or greater.
The stake bead 18 may be formed as an uninterrupted stake bead 18 around an entire perimeter 26 (shown in FIG. 6) of the component contour 12A, or as individual sections 18B extending around corners that circumscribe curves or corners 28 of the component contour. Alternatively, the stake bead 18 may be formed as localized substantially straight sections 18C that do not follow the curves 28 (shown in FIG. 6) and also do not extend fully around the perimeter of the component contour 12A. The stake bead 18 may include tapering of the localized substantially straight section 18C down into the outer region 16 of the material 14 without following the nearest curve 28 around the component contour 12A, such that the region 16 around the subject curve remains substantially flat.
FIG. 7 depicts a method 100 of shaping or forming, via the stake bead profile 19 of the stamping tooling, the component 12 having the stamped component contour 12A for example from the advanced high-strength steel (AHSS). The component 12 may be a structural component for a motor vehicle body (not shown), as described above with respect to FIGS. 1-6. As additionally described above, the stamped component contour 12A includes the wall 22 arranged along the first axis Y1. The method 100 commences in frame 102 where it includes providing the work-piece blank 10 from a formable material, such as the AHSS discussed above. The method then proceeds to frame 104. In frame 104, the method includes forming the first stage 12-1 of the component contour 12A in the work-piece blank 10, such that the first stage of the component contour is bordered by the outer region 16 of the work-piece blank material 14. After frame 104, the method advances to frame 106.
In frame 106, the method includes forming the stake bead 18 in the outer region 16 of the material 14 following the forming of the first stage 12-1 of the component contour 12A. As described above with respect to FIGS. 1-6, the stake bead 18 has the asymmetrical shape 20 when viewed in the cross-sectional plane P1. Following the forming of the stake bead 18, the method proceeds to frame 108. In frame 108, the method includes forming the second stage 12-2 of the component contour 12A in the work-piece blank 10. As described above with respect to FIGS. 1-6, the forming of the second stage 12-2 of the component contour 12A may include stretching the work-piece blank 10 along the first axis Y1 and thereby forming the wall 22. As a result of forming the second stage 12-2, the outer region 16 of the material 14 may become arranged substantially in the plane P2 that is transverse or substantially perpendicular to the first axis Y1.
As described above with respect to FIGS. 1-6, when viewed in the cross-sectional plane P1, the forming of the asymmetrical shape 20 of the stake bead 18 in frame 106 may include forming the first radius R1 and the fourth radius R4 in the transitions between the outer region 16 of the material 14 and the bead. The first radius R1 may be at least two times greater than the fourth radius R4. According to the method, as part of frame 106, the fourth radius R4 may be arranged between the first radius R1 and the wall 22. Alternatively, the first radius R1 may be arranged between the fourth radius R4 and the wall 22. Additionally, when viewed in the cross-sectional plane P1, the forming of the stake bead 18 in the outer region of material may include forming the flat section 24 at the peak 18A of the bead between the second radius R2 and the third radius R3.
As further described above with respect to FIGS. 1-6, the asymmetrical shape 20 of the stake bead 18 is configured to control and/or limit flow of work-piece blank material 14 into the second stage 12-2 of the component contour 12A from the outer region 16 of the material bordering the component contour. Such controlling and/or limiting of the flow of work-piece blank material 14 into the second stage 12-2 of the component contour 12A from the outer region 16 effectively limits the amount of springback and the resultant twist and/or curl of the stamped component contour 12A. Additionally, the asymmetrical shape 20 of the stake bead 18 may facilitate the stretching of the work-piece blank 10 for forming the wall 22 along the first axis Y1 without localized compression of the material 14 in the second stage 12-2 of the component contour 12A. Moreover, at least a part of the stretching the work-piece blank 10 for forming the wall 22 may extend into and stop in the stake bead 18. Following frame 108, the method may proceed to frame 110, where the method includes trimming the outer region 16 of the work-piece blank material 14, including the stake bead 18, to generate the component 12.
As noted above, the formed stake bead 18 may be uninterrupted around the perimeter 26 of the component contour 12A. Alternatively, the formed stake bead 18 may be localized, and form the substantially straight section 18C not extending fully around the perimeter 26. In the embodiment having the localized straight section 18C, the localized straight section 18C of the stake bead 18 may be tapered down into the outer region 16 of the material 14 without following the curve 28 around the component contour 12A. As disclosed, the representative component 12 thus formed from each work-piece blank 10 and having the contour 12A may be a structural reinforcement for a motor vehicle.
Additionally, consistent with the disclosure, the material of the component 12 produced using the above-described method may be a ductile AHSS, for example having a tensile strength of 1000-1200 MPa, or an AHSS having lower ductility but with the tensile strength of around 1500 MPa or greater. Because any deep drawn components would benefit from employing the above-described asymmetrical shape 20 of the stake bead 18, alternatively, the subject component 12 may be stamped from Aluminum or Magnesium alloys, or mild steel. Thus stamped component 12 may also be used for non-structural purposes and in non-automotive applications.
The detailed description and the drawings or figures are supportive and descriptive of the disclosure, but the scope of the disclosure is defined solely by the claims. While some of the best modes and other embodiments for carrying out the claimed disclosure have been described in detail, various alternative designs and embodiments exist for practicing the disclosure defined in the appended claims. Furthermore, the embodiments shown in the drawings or the characteristics of various embodiments mentioned in the present description are not necessarily to be understood as embodiments independent of each other. Rather, it is possible that each of the characteristics described in one of the examples of an embodiment can be combined with one or a plurality of other desired characteristics from other embodiments, resulting in other embodiments not described in words or by reference to the drawings. Accordingly, such other embodiments fall within the framework of the scope of the appended claims.
Patent Application
20190255587
