JP2005246418A - Panel pressing method, and aluminum alloy plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aluminum alloy panel pressing method in which a pressed product has a deep (high) recess or projection, or the shape of the pressed product is complicated, and an instrument panel of a car or the like can be pressed, and an aluminum alloy plate used therefor. <P>SOLUTION: Embossed recesses and projections 9, 10 are formed on one side or both sides of a plate at parts a, b and c corresponding to the panel shape difficult to press which are a part of an aluminum alloy plate 8 as a material to be pressed. A mounting part on other members in the panel is flat, and the aluminum alloy panel having a joining part with other members is easily pressed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a press forming method of an aluminum alloy panel and a material aluminum alloy plate (hereinafter, aluminum is also simply referred to as Al) used therefor.

  In recent years, in the vehicle body field of transport aircraft such as automobiles, improvement in fuel efficiency has been pursued by reducing the weight in response to global environmental problems caused by exhaust gas and the like. For this reason, the application of lighter Al alloy materials such as rolled plates and extruded shapes instead of steel materials conventionally used for automobile bodies is increasing.

  Among these, panels such as outer panels (outer panels) and inner panels (inner panels) of panel structures such as automobile hoods, fenders, doors, roofs, and trunk lids are made of Al-Mg-Si AA to JIS 5000. The use of Al alloy plates such as 6000 or 6000 (hereinafter simply referred to as 6000) is being studied.

  Of these, the 6000 series Al alloy plate basically contains Si and Mg as essential and has excellent age-hardening ability. Therefore, formability is ensured by reducing the yield strength when press-molding the above panels. At the same time, BH properties (baking hardness) can improve the yield strength by heating at the time of relatively low-temperature artificial aging (hardening) treatment, such as paint baking treatment of panels after press molding, and ensure the required strength. , Artificial age hardening, paint bake hardenability).

  The above-mentioned 6000 series Al alloy plate is easily age-hardened at room temperature (room temperature) after the production of the Al alloy plate itself until it is used for each application because of its excellent age-hardening ability. There was a problem that the press formability of the resin deteriorated. Also, including other 5000 series, there is a problem that the press formability to the panel is generally lower than that of the steel plate.

  For this reason, Al alloy plates including 6000 series are particularly difficult to press-mold into automobile inner panels, etc., where the molded product has deep (high) irregularities or the molded product has a complicated shape.

  On the other hand, as a cover (shielding material) called a heat insulator for heat insulation and heat insulation provided in catalytic converters, exhaust guide parts around mufflers, transmission parts, engine mounts, etc., such as automobiles, Application of an Al alloy embossed plate instead of the conventional hot-dip galvanized steel plate has been studied as a sound insulation or cushioning material provided inside the outer panel material such as a hood, roof, door and the like.

  The Al alloy embossed plate is basically an Al alloy plate in which a large number of embossed irregularities are provided on one or both sides of a flat panel panel to increase the apparent thickness of the embossed portion. This unevenness can increase the rigidity and reduce the thickness and weight as compared to a flat panel having the same thickness.

For this reason, for example, there is an example in which an embossed plate of Al alloy having a thickness of 0.4 to 0.5 mm is press-molded into a product shape using a mold as the heat insulator (see Patent Document 1). Although not necessarily made of Al alloy, an example is proposed in which an embossed plate provided with a number of embossed projections on a flat panel is bent into a halved cylindrical body as the outer cylinder of a silencer. (See Patent Document 2). In addition, although not limited to Al alloy, a lightweight high-rigidity panel that suppresses vibration and noise has been proposed as a wall interior panel, etc., with numerous irregularities provided in a staggered pattern on both sides of the flat panel. (See Patent Document 3).
Japanese Patent Laid-Open No. 2000-136720 (Claims, pages 1 to 3, FIG. 1) JP-A-8-296423 (Claims, pages 1 to 3, FIG. 1) Japanese Patent No. 2960402 (Claims, pages 1 to 3, Fig. 1)

Moreover, in order to improve the formability when press-molding the embossed plate of these Al alloys into a member such as the heat insulator, an example in which the height and pitch of unevenness by embossing is specified (see Patent Document 4), An example in which the clearance between the die and the wrinkle retainer plate or the die and punch is made higher than the height of the unevenness by embossing (see Patent Document 5), and further, an example in which the plate thickness is specified in a specific range of 0.20 to 0.39 mm ( (See Patent Document 6).
Japanese Patent Laid-Open No. 2002-60878 (Claims, pages 1 to 3, FIG. 1) JP 2000-288643 (Claims, pages 1 to 3, FIG. 1) Japanese Patent Laid-Open No. 2000-257441 (Claims, pages 1 to 3, FIG. 1)

  These means can be expected to be effective for forming an embossed plate such as a heat insulator having a relatively small area.

  However, since these Al alloy embossed plates have unevenness, a large number of unevennesses remain on the surface of the molded product after molding. For this reason, there is a problem that it is difficult to apply to an automobile panel in which flatness and high dimensional accuracy are required at the time of assembly as a member on the joint surface of a molded product.

  That is, the unevenness due to the embossing is likely to remain as an unevenness in a portion where the molded product panel is attached to another member even after press molding, depending on the height. As a result, the flatness and dimensional accuracy are inferior as compared to a flat mounting portion obtained by press-molding a flat plate, and there is a high possibility that the bonding property with other members as a member, the bonding strength, and the like will be hindered.

  Accordingly, an object of the present invention is to provide an inner part of an automobile, in particular, where a molded product has a deep (high) uneven shape or a complicated shape, and a high flatness and dimensional accuracy are required at a joint portion with another member as a member. An object of the present invention is to provide an aluminum alloy panel press forming method capable of being press formed into a panel and the like, and an aluminum alloy plate used therefor.

  In order to achieve this object, the gist of the aluminum alloy panel press-forming method of the present invention is a part of an aluminum alloy plate that is a press-forming material, and a portion corresponding to a panel shape that is difficult to press-form, on one side of the plate or Concavities and convexities are provided on both sides by embossing, and the mounting portion of the panel with other members is flat.

  Further, the gist of the present invention 6000 series aluminum alloy plate for achieving this object is the embossing used in the above press forming method and providing unevenness on one or both sides of the plate only in the part corresponding to the panel shape which is difficult to press form. It has been processed.

  In the present invention, unevenness by embossing is provided on one side or both sides of a plate, which is a part of an aluminum alloy plate that is a press-molding material and is equivalent to a panel shape that is difficult to press-form. As a result, it is easy to mold even an inner panel in which the molded product has deep (high) irregularities or the molded product has a complicated shape.

  This is because, as will be described later, a plate received from the corner (R portion) of the mold by partially embossing the part corresponding to the panel shape, which is difficult to press-mold, of the material aluminum alloy plate. This is because the local strain concentration is reduced by the presence of the unevenness of the plate.

  In the case of normal material flat plates, the portion corresponding to the panel shape that is difficult to press-mold, the amount of distortion of the plate that is received from the corner of the mold in the portion of the plate that deforms in close contact with the corner of the mold during press molding. Especially concentrated locally. As a result, this leads to breakage of the plate particularly at a portion where the amount of distortion is locally concentrated.

  On the other hand, as will be described later, a plate received from a corner portion of the mold, as will be described later, by embossing the material aluminum alloy plate, which is difficult to press-mold, into a portion corresponding to the panel shape, as in the present invention. The strain concentration is alleviated by improving the bending rigidity due to the presence of the unevenness of the plate. For this reason, the fracture | rupture of the board in press molding is suppressed. Further, even if the BHF is increased to reduce the inflow of material, the sheet can be formed without breaking, so that the height of wrinkles is suppressed.

  Furthermore, by embossing part of the material aluminum alloy plate that is difficult to press-mold, the part corresponding to the panel shape is partially embossed so that the other flat plate part of the material plate is press-molded as usual. The concavo-convex shape does not hinder press molding as in the past. Therefore, these effects synergize to improve press formability.

  In addition, the other flat plate portion of the material plate that does not have an uneven shape by embossing can be flattened by a press molding, so that the mounting portion with the other member in the molded product panel can be flattened. Can be secured.

  Embodiments of the present invention will be specifically described below with reference to the drawings.

(Molded panel)
FIG. 1 is a perspective view of an inner panel (molded product) 1 manufactured by press molding, and FIG. 2 is a sectional view of the molded inner panel 1 joined to an outer panel 6 to form a panel structure. FIG. 3 is a plan view showing an example of the material aluminum alloy plate 8 in which unevenness by embossing is provided on one side or both sides of the plate. Further, FIG. 4 is a cross-sectional view showing another example of the material Al alloy plate 8 provided with unevenness on one side of the plate by embossing.

  In the inner panel 1 having a substantially HAT shape shown in FIG. 1, 2 is a flat top, 3 is a vertical wall of the top 2, 4 is a flat flange surrounding the top, and 5 is a handle of a door provided on the top 2, for example. It is a recessed part equivalent to this fitting part.

  As shown in FIG. 2, the inner panel 1 is joined to an outer panel 6 which is another member. Specifically, the end of the flat flange portion 4 of the inner panel 1 is sandwiched and joined in a bent portion (hem portion) 7 that is bent (hemmed) by bending the end portion of the outer panel 6 180 degrees. It is integrated as a panel structure. The flat flange portion 4 is a flat portion in the material Al alloy plate 8 that is not provided with an uneven shape by embossing.

  Thus, by flattening the portion corresponding to attachment to the other member in the molded product panel (the portion corresponding to the flange portion 4) in the raw material Al alloy plate 8, the portion to be attached to the other member in the molded product panel is formed by press molding. Can be made flat, and the joining property with other members and the joining strength can be secured.

  In such an inner panel 1, the panel-shaped portions that are difficult to press-form are the corners a including the vertical wall portions 3 at the four corners of the top portion 2 and the centers of the top portion 2 to the vertical wall portion 3, respectively, indicated by surrounding oblique lines. The part b, the peripheral part c of the concave part 5 including the periphery, and the like.

  These parts are complex in shape or have a small mold radius (shoulder R). In particular, there is a problem that the amount of distortion of the plate received from the portion tends to be concentrated locally, and in particular, the plate is easily broken.

(Unevenness by embossing)
Therefore, in the case as shown in FIG. 1, the parts (parts) a corresponding to the panel-shaped parts a 1, b 2, c, which are difficult to press-form, such as the raw Al alloy plate 8 before forming shown in FIG. , B, and c are each provided with unevenness by embossing in the area indicated by oblique lines. More specifically, unevenness 9 (represented by white circles in the figure) and unevenness 10 (represented by black circles in the figure) are provided on both surfaces of the material Al alloy plate, for example, a total of 3 rows (for example, 3 in each row). Yes. In FIG. 3, the area indicated by the alternate long and short dash line is an assumed line for forming (shape) of the top 2 and the recess 5 of the inner panel 1.

  These panel-shaped parts that are difficult to press form vary depending on the panel application, such as hood, roof, door, back door, luggage, and trunk lid. However, when there are the corners a and the recesses 5 and the like, depending on these shapes, of course, in common, they easily break during molding, and unevenness is formed on one or both sides of the plate corresponding to these parts. It is preferable to perform the embossing provided.

  Fig. 4 (a) shows the unevenness 9 of width (length) l and height h by embossing the material plate part corresponding to the panel-shaped part that is difficult to press-mold (represented by white circles in Figs. 3 and 5). ) Is provided on one side of the material plate 8 with a space p interposed through the flat portion 11. FIG. 4 (b) is an arrangement example of the unevenness as shown in FIG. 3, and unevenness 9 having the same width (length) l and height h on both surfaces of the material Al alloy plate 8 (in FIGS. 3 and 5). An example is shown in which the white circles) and the irregularities 10 (represented by the black circles in FIGS. 3 and 5) are provided alternately and with a spacing p through the flat portion 11. FIG. FIG. 4 (c) shows an example in which bead-shaped irregularities 16 having a width (length) 1 and a height h are provided at intervals p through the flat portion 11. FIG.

  In the present invention, the portions of the material plate other than the portions (portions) a, b, c corresponding to the panel-shaped portions a, b, c that are difficult to press-mold, such as the portion corresponding to the flange 4, are provided with unevenness by embossing. Without flattening. In particular, the flange portion 4 of the inner panel 1 that is sandwiched and joined in the bent portion 7 of the outer panel 6 is a mounting portion with the other member in the panel, and is flat to ensure the joining property and the joining strength. It is necessary to. For this reason, the unevenness | corrugation by embossing is not provided in the peripheral part of the board corresponded to the attachment equivalent part with other members in such a panel.

  Thus, in this invention, it is preferable to give the embossing which provides an unevenness | corrugation in the single side | surface or both surfaces of a board only to the panel shape equivalent part which is difficult to press-mold. However, if the unevenness provided on the original plate is stretched after press molding and flatness can be secured, the panel shape part a, which is difficult to press the material plate, within a range that does not impair the formability of the entire panel, Concavities and convexities by embossing may be provided in parts other than those corresponding to b and c.

  FIG. 5 is a plan view of the raw material Al alloy plate 8 before forming, which is the same as FIG. 3, but shows another example of the unevenness provided by embossing the raw material plate. As shown in FIG. 3, the arrangement of the irregularities provided by embossing on the parts corresponding to the panel-shaped parts a 1, b 2, and c 3, which are difficult to press-mold, may be arranged in the same way as shown in FIG. As shown in FIG. The upper left array in FIG. 5 is an example in which only irregularities 10 are arranged, the lower left is an example in which only irregularities 9 are arranged, and the upper right arrangement is provided by arranging irregularities 10 and irregularities 9 alternately. Each example is shown. Of course, it is good also as each arrangement | sequence with the same arrangement | positioning of each part of a raw material board using each of these arrangement examples.

  The number of concavo-convex 9 and 10 (number of arrays, number of lines), arrangement method, concavo-convex shape, width (length) l, height h, interval p, etc. provided by embossing depend on the panel shape and molding conditions In particular, in the portion of the plate that deforms in close contact with the corner of the mold, it is determined as appropriate so that the strain concentration of the plate received from the corner of the mold can be relaxed and the effect of preventing the breakage of the plate can be exhibited. . However, the concavo-convex shape does not require a special shape and may be a trapezoidal shape such as a normal smooth arc shape or semicircular shape, or a bead shape.

  In addition, in order to exhibit the above-described formability improvement effect of the unevenness 9 and 10 provided by embossing in the range of about 0.5 to 2.0 mm of the thickness of each inner panel used in a normal automobile, the unevenness 9 and The width (length) l of 10 is preferably in the range of 5 to 15 mm, the height h is in the range of 1 to 2.5 mm, and the interval p is in the range of 5 to 15 mm.

(Embossing method)
A method of providing the material flat Al alloy plate by partially or patterning the unevenness due to the embossing is as follows. In other words, for a cut or coiled Al alloy plate, a flat Al alloy plate is pressed by a press die having a corresponding unevenness or a rolling roll provided at a portion corresponding to the unevenness setting portion of the plate. Or rolling. In this rolling, the roll is rotated and intermittently brought into contact with the Al alloy plate while rolling the Al alloy plate in the coil state, or the long Al alloy plate is continuously passed through the roll (rolling down). Thus, the embossed plate of the present invention can be manufactured continuously.

(Press molding method)
The press molding method in the present invention can basically use the press molding method and molding condition range of a normal panel molded product. This is also an advantage of the present invention.

  FIG. 6 partially shows an embodiment in which the material Al alloy plate 8 provided with the unevenness 9 of FIG. 4 is press-molded into a molded panel having a relatively large area by embossing, in relation to the mold. FIG. 7 shows a comparative example, in which a state in which a conventional (normal) flat material Al alloy plate 15 is press-formed is partially shown in relation to a mold.

  6 and 7, reference numeral 12 denotes a punch having a molding surface having a predetermined diameter and a shoulder radius in three stages 12a, 12b and 12c. Reference numeral 13 denotes a die having a molding surface similar to that of the punch 12 and having a predetermined shoulder radius. FIGS. 6 and 7 show a state in which the raw material Al alloy plate is formed by relatively moving both the punch 12 and the die 13 for example.

  In FIG. 6, the material Al alloy plate 8 provided with the unevenness 9 has an appropriate blank size commensurate with the forming panel size. In addition, a general lubricating oil or a general rust preventive oil may be applied to the material Al alloy plate 8 in the same manner as a normal flat plate press molding. Furthermore, the method of providing clearance with the die face surface may be designed in accordance with the press forming of a normal flat plate, except that the height of the unevenness 9 is considered as an apparent plate thickness added to the plate thickness of the material Al alloy plate 8. . The same applies to BHF (wrinkle holding force) applied to the material Al alloy plate 8.

  The material Al alloy plate 8 provided with the unevenness 9 according to the present invention has a relatively high bending rigidity. Therefore, as shown in FIG. 6, the phenomenon of `` wrapping '' along the punch forming surfaces 12a, 12b, and 12c hardly occurs, and the punch forming surfaces 12a, 12b, and 12c are curved more gently outward. Thus, the concave and convex portions 9 are formed so as to be stretched sequentially. For this reason, the same effect as increasing the shoulder R of the mold is obtained, and the local concentration of the distortion amount of the plate received from the corner of the mold is alleviated. As a result, the breakage of the plate at the portion where the strain amount is locally concentrated is suppressed. Moreover, the sweetness of the molded shape, the shape freezing property, and the shape accuracy, which are generated when the shoulder R of the mold is increased, are not sweetened.

  Further, even if the BHF is increased to reduce the inflow of material, the sheet can be formed without breaking, so that the height of wrinkles is suppressed. At this time, by controlling the tension of the plate by BHF or the like of the mold 13, it is possible to flatten the respective unevenness 9 and flatten the molded panel surface. When appearance such as flatness and flatness of the molded panel surface is required, the molding panel surface is flattened by flattening the unevenness in this way.

  On the other hand, in FIG. 7 of the comparative example, the normal flat material Al alloy plate 15 has a low bending rigidity. The phenomenon of “wrapping” occurs along 12b and 12c. For this reason, the amount of distortion of the plate received from the corners of the mold is particularly concentrated locally at the portions of the plates that are in close contact with the corners of the molding surfaces 12a, 12b, 12c during press molding. As a result, this leads to breakage of the plate particularly at a portion where the amount of distortion is locally concentrated.

  In the present invention, the other flat plate portion of the material plate is press-molded as usual by embossing the surface of the material aluminum alloy plate, which is difficult to press-mold, to a part corresponding to the panel shape. The For example, even when a draw bead portion is provided in a mold, a draw bead portion is provided in the mold so that a flat portion other than a material plate portion provided with unevenness passes through the draw bead portion, or a raw material plate portion provided with unevenness is drawn bead Even when passing through the portion, by setting the height of the projections and depressions that can pass through, the influence on the draw bead portion can be prevented.

(Al alloy)
The Al alloy used in the present invention is typically a 3000 series, 5000 series, 6000 series, 7000 series Al alloy, etc. that is widely used for this kind of structural member application, or that is stipulated in AA or JIS standards, or similar to the regulations. Preferably used. These Al alloys have relatively good formability. The mechanical properties such as tempering and strength of these Al alloys are appropriately selected according to the required characteristics of the panel member.

  However, as described above, the 6000 series Al alloy plate ensures formability by reducing the yield strength during press forming to the panel, and relatively low-temperature artificial aging (hardening) such as paint baking treatment of the panel after press forming. It is age-hardened by heating during processing to improve yield strength, and has BH properties that can secure the required strength. In addition, since the alloy element amount is small, the recyclability of the waste material to the original 6000 series Al alloy is also excellent. Accordingly, when these characteristics are required for inner panel applications, it is preferable to apply a 6000 series Al alloy plate.

  The molded panel 1 of the approximately HAT shape in Fig. 1 is embossed as an irregularity, pattern 1: semicircular irregularity 9 in Fig. 4 (a) and pattern 2: semicircular shape in Fig. 4 (b) The material plates (blanks) provided with the unevenness 9 and 10 and the pattern 3: the bead-shaped unevenness 16 of FIG. 4 (c) were prepared, and the press formability was evaluated. The same unevenness was provided in the arrangement as shown in FIG. 3 in common with each example. For press forming, use the press shown in Figs. 6 and 7, apply commercially available rust-preventive oil and form, determine the limit BHF at which cracking of the plate occurs, and determine the maximum height of wrinkles on the seal surface at the limit BHF. The thickness (mm) was measured and evaluated. These results are shown in Table 1 together with the shape conditions of the irregularities (Invention Examples 1, 2, and 3).

  In this test, the formability was evaluated mainly by the maximum wrinkle height, the allowable value of the maximum wrinkle height was 0.4 mm, the larger one was evaluated as ○, and the smaller one was evaluated as ×.

  For comparison, an example in which a conventional flat plate without embossed irregularities was coated with a commercially available rust preventive oil was formed as Comparative Example 4, and this conventional flat plate was more lubricated than a general rust preventive oil. As a comparative example 5, the formation was similarly tested using a commercially available solid lubricant having excellent resistance. These results are also shown in Table 1.

The material plate is common to each example, AA 6016 Al alloy standard composition excess Si type 6000 series Al alloy T4 plate (plate thickness 1.0 mm, tensile strength σ _y : 245 MPa, 0.2% proof stress: 143 MPa, elongation δ 28 .7%).

  As can be seen from Table 1, Invention Examples 1, 2, and 3 show that the limit BHF is relatively high, and even if the BHF is increased and the inflow of material is reduced, it can be formed into a panel without cracking. . In addition, the maximum height of wrinkles is relatively small as a result of increasing the BHF and reducing the inflow of material.

  On the other hand, Comparative Example 4 of the conventional flat plate material shows that the limit BHF is lower than that of the invention example, and if the BHF is lowered and the inflow of material is not increased, cracks will occur. . Moreover, as a result of lowering the BHF and increasing the inflow of material, the maximum height of the wrinkles is remarkably larger than that of the inventive example. In Comparative Example 5 where a solid lubricant is used for a conventional flat plate material, due to the unique effect of the solid lubricant, although the limit BHF is relatively high, the inflow of material increases, and the maximum wrinkle height is the invention example. In comparison, it is significantly larger.

  Therefore, from these results, it can be seen that the present invention has a significant press formability improvement effect compared to the conventional flat plate material use, and further has a press formability improvement effect more than the conventional solid lubricant use, The significance of the present invention is supported.

  According to the present invention, in particular, a press molding method of an aluminum alloy panel capable of press molding to an inner panel of an automobile, etc., in which the molded product has deep (high) unevenness or the molded product has a complicated shape, and this An aluminum alloy plate used for the above can be provided. For this reason, the application of aluminum alloy plates is expanded to the field of panel structures such as hoods, fenders, doors, roofs, trunk lids, and the like of automobile bodies such as automobiles.

It is a perspective view which shows one embodiment of the shaping | molding inner panel which concerns on this invention. It is a perspective view which shows the one aspect | mode of joining of a shaping | molding inner panel and an outer panel. It is a top view which shows one embodiment of the raw material aluminum alloy plate which concerns on this invention. It is sectional drawing which shows the embodiment of the raw material aluminum alloy plate which concerns on this invention. It is a top view which shows another embodiment of the raw material aluminum alloy plate which concerns on this invention. It is a fragmentary sectional view showing one embodiment of the press molding method of the present invention. It is a fragmentary sectional view showing one embodiment of the conventional press molding method.

Explanation of symbols

1: Molded panel, 2: Top, 3: Vertical wall, 4: Flange, 5: Recess, 6: Outer panel,
7: Bending part, 8: Al alloy plate, 9, 10, 16: Concavity and convexity, 11: Flat part, 12, 13: Mold,
15: flat plate, a, b, c: difficult-to-mold part,

Claims (5)

  A method for press-forming an aluminum alloy panel, which is a part of an aluminum alloy plate that is a press-molding material, and is provided with irregularities by embossing on one or both sides of the plate in a portion corresponding to a panel shape that is difficult to press-form, A method for press-molding an aluminum alloy plate, characterized in that a mounting portion with other members in is flat.   The press forming method of the aluminum alloy plate according to claim 1, wherein unevenness by embossing is provided on one side or both sides of the plate only in a portion corresponding to the panel shape where press forming is difficult.   The aluminum alloy plate press forming method according to claim 1, wherein the panel is an automobile inner panel and is joined to an outer panel at a portion where the panel is attached to the other member to constitute a panel structure.   The aluminum alloy sheet press forming method according to any one of claims 1 to 3, wherein the aluminum alloy sheet is a 6000 series aluminum alloy. An aluminum alloy plate, which is used in the press forming method according to any one of claims 1 to 4 and is embossed to provide unevenness on one side or both sides of the plate only on a portion corresponding to a panel shape that is difficult to press form.

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