JP2015074000A - Differential thickness bracket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cup-shaped differential thickness bracket which can further reduce thickness and weight in addition to securement of strength and rigidity equivalent to existing strength and durability, and which can be easily manufactured by virtue of excellent moldability and the like.SOLUTION: A bracket 10 is press-molded in a cup shape from a plate-like differential thickness blank made of an aluminum alloy extruded shape. The differential thickness bracket includes the thickest cup bottom 11, a cylindrical vertical wall 12, an opening 17, and flanges 13 and 14. The differential thickness bracket is joined to each of other components via the cup bottom 11 and the flanges 13 and 14.

Description

  The present invention relates to a bracket (support, fixture) used for component mounting, and relates to a differential thickness bracket made of an aluminum alloy that is light and high in strength and easy to manufacture.

  In general, when components are attached, they are often coupled via some kind of bracket. Here, when at least one of the parts to be joined is an aluminum alloy material, there is a demand to use the aluminum alloy material for the bracket in consideration of weight reduction, weldability, electric corrosion resistance, and the like.

  However, the aluminum alloy material often has a problem that the material cost is higher than that of a steel material used conventionally, particularly a steel plate. For this reason, aluminum alloy brackets are also required to be reduced in material cost and weight compared to steel plate brackets.

  Further, many of these brackets require strength and rigidity when loaded. Taking automobile parts with strong demands for weight reduction as an example, collision-resistant energy absorbing parts such as brackets and door beams and brackets that join frames are required to have particularly high strength and rigidity.

  For such an aluminum bracket, a 5000 series aluminum alloy plate (rolled plate) having relatively good weldability has been used as a forming material. However, particularly when applied to a mounting bracket such as an energy absorbing component, it is often relatively thick to secure strength, which increases the weight and material cost. For this reason, an aluminum alloy extruded shape having a relatively high strength is often used for a bracket (bumper stay) or the like for joining an aluminum alloy bracket.

  A joint bracket using such an aluminum alloy extruded shape directly (as it is) has a restriction unique to the extruded shape, ie, a uniform (constant) cross section in the longitudinal direction. For this reason, it becomes a two-dimensional curved surface with respect to the load direction of a load, and becomes weak with respect to the load to a specific direction. For this reason, in order to satisfy the required crushing strength and impact energy absorption performance as a vehicle bumper stay (hereinafter also simply referred to as a stay) that is one use of the bracket, it is necessary to make it relatively thick. As higher strength is required, there is a problem that the weight increases and the material cost also increases.

  In order to solve this problem, a bracket in which the thickness of each part is approximately uniform is formed by pressing an aluminum alloy plate (rolled plate) having a uniform thickness into a cup shape instead of the extruded shape as the bumper stay. A structure (cup-shaped bracket) has been proposed by the present applicant (see Patent Documents 1 to 4).

  As shown in the perspective views in FIGS. 8 and 9, the cup-shaped brackets (stays) 101 and 102 each having a cup bottom portion 103 having a circular or elliptical shape in plan view are peripheral portions of the cup bottom portion 103. A cylindrical vertical wall 104 that rises with an arcuate corner R and an opening 106 surrounded by the vertical wall 104. A flat flange 105 projecting outward from the peripheral edge of the vertical wall 104 is integrally formed by press molding.

  8 and 9, as the bumper stay, the cup bottom 103 side is attached to the front end 61 side of the side frame 60, and the cup opening 106 side is connected to the rear wall of the bumper reinforcing member 50 via the flange 105. A mode attached to the side 52 is shown.

  More specifically, in the embodiment of FIGS. 8 and 9, the cup bottom portion 103 side of the cup-shaped brackets 101 and 102 is provided on the side frame front end portion 61 side via a plurality of through holes 107 provided in the cup-shaped brackets 101 and 102. The plurality of through holes 62 are attached by mechanical joining means such as bolts and nuts. On the other hand, the cup opening 106 side is mechanically connected to a plurality of through holes 53 provided on the rear wall side 52 of the bumper reinforcing member 50 via a plurality of through holes 107 provided in the flange 105, such as bolts and nuts. It is attached by a simple joining means. With respect to this mounting method, the cup bottom 103 side and the cup opening 106 side are opposite to each other, the cup bottom 103 side is on the rear wall side 52 of the bumper reinforcing member 50, and the cup opening 106 side is on the side frame tip 61. You may make it attach to the side.

  Unlike the two-dimensional curved surface with respect to the load direction of the load of the extruded profile, the cup-shaped brackets 101, 102 have a cup-shaped bracket 104 due to the presence of the three-dimensional cylindrical vertical wall 104. Together with the bottom portion 103 and the flange 105 at the peripheral portion, the structure has a three-dimensional curved surface with respect to the load direction from the upper direction of each figure. This is advantageous in that the strength and rigidity of the bracket can be secured even with a structure having a relatively thin plate thickness.

JP 2006-347527 A JP 2007-1386 A JP 2008-195224 A JP 2011-20668 A

  However, in recent years, higher strength has been demanded even for such cup-shaped brackets. In order to achieve such an increase in the strength of the bracket, it is necessary to increase the strength or thickness of the aluminum alloy material in the prior art. However, depending on the use conditions such as the above-mentioned bumper stay, a high strength material exceeding 300 MPa is required. However, there is no material that can satisfy (correspond to) such a high strength in the general aluminum alloy sheet material currently distributed.

  Moreover, when it is going to increase the thickness of the rolling plate which is a molding material of a cup-shaped bracket and to satisfy the strength requirement, it is necessary to uniformly increase the thickness of the entire plate in a normal rolled plate. This is because a normal rolled plate has a uniform plate thickness regardless of the part, and thus it is difficult to partially thicken and make a difference in thickness. For this reason, increasing the thickness of the material plate leads to an increase in the overall thickness of the cup-shaped bracket with a generally uniform plate thickness, leading directly to an increase in the weight of the component. It becomes a problem. In addition, in order to increase the strength, the required thickness may be 3 mm or more, which is a special thickness that is thicker than the thickness of the aluminum alloy sheet (cold rolled sheet) that is generally distributed. A large plate material is required, and the material cost is high.

  In addition, there is an increasing demand for a higher bracket height for the purpose of improving design flexibility. However, in aluminum alloy sheet materials that are inferior in formability compared to mild steel sheets, formability often becomes a problem even at the current height, and in fact, it is difficult to meet the demand for this height increase. Depending on the application, it is possible to improve the fracture limit of the material by forming the material plate in a warm or high temperature state, etc., but this greatly increases the processing cost and adds heat. Changes in materials, deterioration of shape accuracy, etc. are problems. Therefore, it is desired to develop a bracket structure that can be formed by ordinary cold forming (press forming) without using special press forming.

  In view of this point, the present invention provides a cup-shaped differential thickness bracket that can be made thinner and lighter while ensuring the same level of strength and rigidity as the current one, and is excellent in formability and easy to manufacture. The purpose is to do.

In order to achieve the above-described object, the differential thickness bracket of the present invention is a bracket in which a plate blank made of an aluminum alloy extruded shape is press-molded, and a cup and a flange connected to the cup are integrated. Because
The plate-like blank consists of a differential thickness blank having a central thick part and thin parts on both sides in the extrusion direction,
The thick portion at the center of the differential thickness blank is formed at least in the cup, and the thin portions on both sides of the differential thickness blank are formed integrally with the flange connected to at least the cup,
The bracket has a cup bottom that is the thickest, a cylindrical vertical wall that rises from the peripheral edge of the cup bottom, an opening surrounded by the vertical wall, and a peripheral edge of the vertical wall. And the flange projecting outward from the
Joined to other parts at the cup bottom and the flange, respectively.
That is.

  According to the present invention, the bracket formed in a cup shape is combined with the flange of the cup bottom portion or the peripheral portion due to the presence of the cylindrical vertical wall, and a three-dimensional curved surface or a three-dimensional surface with respect to the load direction of the load. It has a shell structure. For this reason, the strength and rigidity of the bracket can be ensured even with a relatively thin structure.

  In addition, according to the present invention, a three-dimensional curved surface or a three-dimensional shell structure is provided by using an extruded profile that can be easily and partially enlarged in advance at the time of extrusion as a blank that is a press-molded material. doing. As a result, the thickness of the cup bottom portion or the like that requires strength is appropriately thickened in advance, and the other portions that do not need to be thickened are thinned. For this reason, it is possible to efficiently reduce the weight of the parts and reduce the material cost while ensuring the same level of strength and rigidity as the current one. Further, it is easy to produce a blank bracket by press molding.

  On the other hand, in order to use an aluminum alloy plate as a blank and to form a similar partial difference thickness blank, plate materials having different plate thicknesses are welded to each other at the ends or the difference thickness Special additional processing such as rolling or plate forging is required, and the cost is significantly increased. In addition, when plate materials with different plate thicknesses are welded together to form a differential thickness blank, the quality of the welded portion is ensured. In particular, in the case of a heat treatment type alloy such as a 6000 series alloy, the plate material characteristics in the vicinity of the welded portion are further increased. Deterioration, such as softening, becomes a problem.

  Furthermore, the differential thickness bracket according to the present invention has both the strength of the bracket and the formability at the time of press molding, as compared with the case of the conventional cup-shaped bracket having the same thickness for each part. Improvement can be expected.

  Even if the flange of the present invention is thinner than the cup bottom, the flange located on the outer peripheral side and the vertical wall joined to the outer peripheral flange have a small effect on the strength characteristics of the bracket, and the thin wall is efficiently And weight reduction.

  Furthermore, the bracket of the present invention has extremely good formability compared to a bracket formed of a plate material or an extruded material having the same thickness regardless of the part.

It is a perspective view which shows one Embodiment of the difference thickness blank of this invention bracket raw material. It is explanatory drawing which shows one Embodiment of this invention bracket. It is explanatory drawing which shows other embodiment of this invention bracket. It is explanatory drawing which shows other embodiment of this invention bracket. It is explanatory drawing which shows other embodiment of this invention bracket. It is explanatory drawing which shows the one aspect | mode of attachment of this invention bracket. It is a perspective view which shows a comparative example bracket. It is sectional drawing which shows the conventional bracket. It is sectional drawing which shows the conventional bracket.

  Embodiments of the bracket of the present invention will be described in detail below with reference to the drawings.

  FIG. 1 is a perspective view showing an embodiment of a differential thickness blank made of an aluminum alloy extruded profile, which is a molding material of the bracket of the present invention.

  FIG. 2 is an explanatory view showing an embodiment of the bracket of the present invention formed by press-molding the differential thickness blank of FIG. 2A is a perspective view, FIG. 2B is a top view, FIG. 2C is a front view, and FIG. 2D is a side view. 3-5 is explanatory drawing which shows the modification of the difference thickness blank of FIG. 1, (a) of each figure shows a perspective view, (b) shows a top view, respectively.

Differential thickness blank:
The differential thickness blank 1 in FIG. 1 is a plate-shaped blank made of an aluminum alloy extruded profile. The differential thickness blank 1 which is an extruded profile is an extrusion of the differential thickness blank 1 indicated by arrows with a thick portion 2 at the center and thin portions 3 and 4 on both sides in the extrusion direction (longitudinal direction). It has over the direction. Reference numerals 5 and 6 denote end portions (both end portions) in the longitudinal direction of the extrusion (blank longitudinal direction), and reference numerals 7 and 8 denote end portions (both end portions) in the width direction of the blank 1 (direction orthogonal to the extrusion).

  Here, since the differential thickness blank 1 which is an extruded shape has a uniform cross section (extrusion cross section) over the extrusion direction (longitudinal direction), it is on the thick part 2 at the center and on both sides thereof. The thin portions 3 and 4 extend in the extrusion direction, and the width thereof is constant (uniform). The size and shape of these differential thickness blanks 1 are selected according to the design of the shape of the bracket to be molded, and need not necessarily be a flat plate shape. Moreover, the width | variety and thickness of the thick part 2 of the center of the difference thickness blank 1, and the thin parts 3 and 4 in the both sides also correspond to each site | part of these difference thickness blanks of the bracket to shape | mold, respectively. It is selected according to the design of the shape of the vertical wall, flange, and flange.

  In the difference thickness blank 1, the difference in thickness between the thickness difference portions between the central thick portion 2 and the thin portions 3 and 4 on both sides thereof is an abrupt plate thickness difference (substantially relative to the flat surface of each portion). However, in consideration of the fact that press molding is easy or feasible, the slope changes gently as shown in FIG. A surface is preferred.

  The aluminum alloy used for the differential thickness blank 1 (bracket) according to the present invention increases its strength and reduces the thickness of each part, thereby reducing the weight of the bracket and improving the energy absorption characteristics. And it selects from a viewpoint that the press moldability to a bracket is good. According to this viewpoint, the aluminum alloy to be used is selected from high-strength 5000 series, 6000 series, and 7000 series aluminum alloys.

  For the purpose of securing light weight and strength, a 7000 series alloy is desirable. In the case of a 7000 series alloy, the 7000 series alloy is difficult to manufacture (roll), and it is advantageous for reducing the weight of the component in that a higher material strength can be secured as compared with a plate that is not normally used. Incidentally, the 7000 series alloy has a problem that the formability decreases as age hardening progresses, but after extrusion, it is pressed into a bracket in a relatively short time, or before press forming, a short time is required. What is necessary is just to shape | mold and to shape | mold by performing a restoration process.

  Further, when corrosion resistance, SCC resistance, etc. are required, 5000 series and 6000 series alloys can be used. Even in this case, compared to a press-molded bracket or an extruded profile bracket having the same plate thickness regardless of the conventional part, it is possible to ensure lighter weight and higher strength due to the effect of part shape and thickness difference. Extruded hollow shapes made of these aluminum alloys are press-molded after hot extrusion, and then subjected to solution treatment and quenching treatment (quality symbol T4), subsequent aging treatment (quality symbol T6), overaging. The treatment (quality-specific symbol T7) is appropriately performed and used as the differential thickness blank 1 (bracket).

Press forming of differential thickness blank:
The present invention bracket 10 shown in FIGS. 2 and 3 to 5 is formed by press-molding the differential thickness blank 1 of FIG. In addition, in the top view of each (b) of FIGS. 3-5, the correspondence of the thick part 2 and the thin parts 3 and 4 of the difference thickness blank 1 of an extruded material, and each site | part of the molded bracket 10 is also shown. Shown with dotted lines.

  These brackets 10 have a cylindrical shape in which the cup is the thickest, and has a flat, flat bottom 11 and an arcuate corner R that rises from the peripheral edge of the bottom 11. It consists of a vertical wall 12 and an upward opening 17 formed at the peripheral edge of the vertical wall 12. Further, flat and flat flanges 13 and 14 are formed in a shape protruding from the peripheral edge of the vertical wall 12 to the outside (side) of the bracket.

  Here, in the differential thickness blank 1 of FIG. 1, a portion surrounded by a dotted line and including the central thick portion 2 at the center and including a part of the thin portions 3 and 4 is mainly the bottom portion 11 of the cup 10 of the bracket 10. Or the vertical wall portion 12 is formed. At the same time, the thin portions 3 and 4 on both sides of the differential thickness blank 10 are respectively formed integrally with the cups on the flanges 13 and 14 connected to the cup of the bracket 10.

  Therefore, the side ends 7 and 8 of the thin portions 3 and 4 on both sides of the differential thickness blank 10 correspond to the side ends 18 and 19 of the flanges 13 and 14 connected to the cup of the bracket 10, respectively. Yes.

  Further, by adjusting the length (width) of the thick portion up to the end portions 5 and 6 in the extrusion direction of the differential thickness blank 1, the cup 10 of the bracket 10 formed from the thick portion of this portion is adjusted. The height of the walls 15 and 16 can be adjusted. That is, as shown in FIGS. 2, 3, and 4, vertical walls (also referred to as cutout portions) 15 and 16 having a lower back (height) than the vertical wall 12 are valleys of the vertical wall portion 12 of the bracket 10, The flanges 13 and 14 are connected to each other at their ends. The vertical walls (also referred to as notches) 15 and 16 having such a low height are the lengths of the thick portions up to the end portions 5 and 6 in the extrusion direction of the above-described differential thickness blank 1. 1 can be formed by cutting (cutting out) each of the end portions 5 and 6 so as to be short (small) and to reduce the wall forming material.

  Incidentally, the molding of the differential thickness blank 1 of FIG. 1 to the bracket 10 of FIG. 2 can use a normal press molding method and apparatus, and this is also an advantage of the present invention.

  For example, in the differential thickness blank 1 of FIG. 1, the ends 7 and 8 of the thin portions 3 and 4 are sandwiched by a blank holder and the portion surrounded by a dotted line is pressed with a punch. The shape of the bracket 10 is formed by drawing or overmolding in cooperation with the female mold having the final shape of the bracket 10. Incidentally, it is difficult to control the difference in thickness (sheet thickness) of each part of the molded product by press molding (control of the amount of material flowing into the mold). For example, there is a risk of fracture if the thickness is changed by substantially 10% during press molding. Therefore, from this point as well, it is necessary to preliminarily make a thickness difference in accordance with the degree and condition of the thickness difference of the bracket at the stage of the extruded material, which is a molding material. I understand the necessity.

Differential thickness bracket structure:
As will be described later, the bracket 10 according to the present invention includes several portions on the outer surface (upper side in the drawing) of the flat and flat flanges 13 and 14 disposed on the opening 17 side, and a flat and flat cup bottom. 11 are connected to other parts by mechanical or welding or a combination thereof on the outer surface (lower side of the figure).

Cup bottom 11:
For this reason, at least the joint surface on the lower surface side of the figure of the cup bottom portion 11 is a flat and flat plate having a certain size (wideness) in order to ensure jointability and joint strength in the case of welding or mechanical joining. ) Area must be secured (has). However, the planar shape (in plan view) of the cup bottom 11 is not limited to the circular shape as shown in FIGS. 4 and 5, but may be an elliptical shape as shown in FIGS. 1 and 3, or even an indefinite shape. good.

  When any load such as a collision load as in the case of the stay described above is applied to the bracket 10, the load is concentrated on the joint portion of the cup bottom 11. Therefore, the cup bottom 11 needs to be the thickest of the cup-shaped elements. If the thickness of the cup bottom 11 is too thin, the strength and rigidity of the bracket of the bracket 10 are significantly reduced. For this reason, it is preferable that the thickness (plate thickness) of the thick portion 2 at the center of the differential thickness blank 1 which is an extruded profile is held as it is without being reduced (thinned) as much as possible by press molding.

Cylindrical vertical wall 12:
The cylindrical vertical wall 12 that rises from the peripheral edge of the cup bottom 11 and exists three-dimensionally has a basic function of making a three-dimensional curved surface with respect to the load direction of the load of the cup-shaped bracket 10. For this purpose, it is necessary to exist in a cylindrical shape over the entire circumference of the periphery of the cup bottom 11 so as to form a three-dimensional curved surface with respect to the load direction of the bracket 10.

  However, like the bracket 10 in FIGS. 2 to 5, it is not necessary to continuously exist in a cylindrical shape over the entire periphery of the cup bottom 11, and there is a peripheral portion without the cylindrical vertical wall 12. May exist. In the bracket 10 of FIGS. 2 to 5, the cylindrical vertical wall 12 continuously exists over the entire periphery of the cup bottom 11, but the height thereof is not constant, and the vertical wall 12 of the bracket 10 is not constant. The vertical walls 15 and 16 are shorter than the vertical wall 12 and connect the flanges 13 and 14 to each other at their ends. Such short vertical walls 15 and 16 correspond to the portions of the end portions 5 and 6 in the longitudinal direction of the blank 1, and such a narrow region (region having a small area) is press-molded, The vertical walls 15 and 16 are shorter than the vertical wall 12. The short vertical walls 15 and 16 secure the strength and rigidity of the bracket 10 (to the extent that there is no trouble) and reduce the material of the vertical wall 12 to be filled, thereby reducing the weight.

  In the case where such short vertical walls 15 and 16 are provided, the cup bottom 11 and / or part of the cylindrical vertical wall 12 of the differential thickness bracket 10 may be cut out after press molding, The process increases. For this reason, the differential thickness blank 1 is previously provided with a narrow region (region having a small area) like the end portions 5 and 6 in the longitudinal direction of the blank 1 and is provided due to the restriction of the amount of material by press molding. Is more reasonable. That is, in order to make these short vertical walls 15 and 16 and flanges described later partially exist, a part corresponding to the cup bottom 11 of the thick part 2 at the center of the blank 1 and the thin parts 3 on both sides. When a part corresponding to the four cylindrical vertical walls 12 or a part corresponding to the flanges 13 and 14 is selected and cut out in advance, the notching step after press molding can be omitted or reduced. Therefore, it is preferable.

  Even if the thickness (plate thickness) of the cylindrical vertical wall 12 is relatively thin, the strength and rigidity of the bracket can be ensured because of the cylindrical three-dimensional structure. The thickness is designed in consideration of ensuring the strength and rigidity and the thickness of the cup bottom 11. For example, as long as there is no problem in weight reduction, at least the rising portion from the cup bottom portion 11 may be equal to or close to the cup bottom portion 11. In addition, regardless of the height, from the rising portion from the cup bottom 11 to the boundary between the opening 17 and the flanges 13 and 14 is set to a constant thickness, or partially thinned according to the height, etc. The thickness may be increased.

Flange 13, 14:
At least the joining surface on the upper surface side of the drawings of the flanges 13 and 14 is also a flat, flat plate-like constant in order to ensure the joining property and the joining strength in the case of welding or mechanical joining, like the cup bottom portion 11. It is necessary to secure (have) an area of size (width). Further, the planar shape (in a plan view) of the flanges 13 and 14 is not limited to an annular shape continuously existing over the entire periphery of the cup bottom 11 as shown in FIG. As shown in notches 15 and 16 shown in 3 and 4, there may be an intermittent portion such as a portion without a flange. Further, the flanges 13 and 14 are rectangular or rectangular flat plates in a plan view as shown in FIGS. 2, 3, and 4, which are continuously present over the entire length of the both sides of the cup bottom 11 or over the entire longitudinal direction. It is not limited to the shape. For example, an irregular and discontinuous flat plate shape in plan view, such as a portion without a flange or a narrow width portion, may exist within these flat plate ranges.

Planar shape of the flange:
Here, a preferable design of the flange in plan view will be described below.
The elongation at break of the plate-shaped aluminum alloy extruded profile (blank) used in the present invention is lowest when tension is applied in a direction parallel to the extrusion direction of the blank. The elongation at break increases sequentially in the order of the direction orthogonal to the extrusion direction and the direction of the extrusion and 45 ° or 135 °.

  For this reason, in FIGS. 2 (b), 3 and 4, the flanges 13 and 14 of the differential thickness bracket 10 are indicated by the vertical arrows in the figure with the center point C of the bracket existing in the cup bottom 11 as a reference. It is preferable that it exists in the position of the direction of at least 45 degrees and 135 degrees with respect to the extrusion direction of the plate-shaped blank (1) to show. When this is indicated by the presence range of the flange, it includes the position (range) in the 45 ° direction or 135 ° direction in the extrusion direction and within the range from 30 ° direction to the orthogonal direction with respect to the extrusion direction, and 150 ° from the orthogonal direction. It is preferable to exist at least within the range of directions. As a result, it is possible to improve the breaking limit during press molding, and the bracket 10 that is a deeper drawn product can be obtained.

  The bracket 10 shown in FIGS. 2, 3, and 4 is a typical example in which a flange located in the pushing direction does not exist in the cutout portions 15 and 16. At the same time, the flanges 13 and 14 are also typical examples in which the flanges 13 and 14 are located at positions of at least 45 ° and 135 ° with respect to the extrusion direction with respect to the center point C of the differential thickness bracket 10, and only the weight reduction is achieved. In addition, there is an effect of improving press formability. However, when the flanges 13 and 14 are present at positions in the directions of at least 45 ° and 135 °, the shape in plan view is substantially the same with respect to the extrusion direction as shown in FIGS. It doesn't have to be width. For example, the flange width is sequentially changed according to the angle (position) with respect to the extrusion direction with respect to the center point C, such as a butterfly blade shape that narrows the flange width in the direction orthogonal to the extrusion direction. Also good.

  On the other hand, as shown in FIG. 5, in the annular flange shape in which the flanges 13 and 14 are continuously present over the entire periphery of the cup bottom 11, the flanges 13 and 14 are provided with the differential thickness bracket 10. With respect to the center point C of the sheet, the sheet blank 1 is present at a position of at least 45 ° and 135 ° with respect to the extrusion direction of the plate blank 1 indicated by the arrow, but is also present in the extrusion direction. Therefore, the press formability of the bracket 10 shown in FIGS. 2, 3, and 4 is superior to the bracket 10 of FIG.

  As described above, this is a problem peculiar to an aluminum alloy extruded profile, in which the elongation in the direction parallel to the extrusion direction of the plate blank 1 is significantly inferior to the other directions, and the elongation at break is in the extrusion direction. This is because the tension is the lowest when tension is applied in a parallel direction. Therefore, as shown in FIGS. 2B, 3, and 4, the flanges 13 and 14 of the differential thickness bracket 10 are pushed in the direction in which the plate blank 1 is indicated by an arrow with respect to the center point C of the differential thickness bracket 10. It is preferable that the position is not present at least. When this is indicated by the existence range of the flanges 13 and 14, the flanges 13 and 14 are based on the center point C (existing in the cup bottom 11) of the differential thickness bracket 10 with respect to the extrusion direction of the plate blank (1). Therefore, it is preferable that it does not exist within a range of at least ± 20 °.

  Thus, if the flange part which exists in the position of the direction of extrusion of the flanges 13 and 14 or a direction parallel thereto is eliminated, the direction of least elongation, that is, the breakage of the blank 1 made of the extruded shape material is produced during press molding. It is possible to reduce the tension in the direction in which it tends to occur. Thereby, it becomes difficult to produce the fracture | rupture at the time of press molding of the blank 1, and the bracket 10 which is a deeper (higher height) draw-molded product can be obtained.

Effect of bracket 10:
3-5, the junction part of the bracket 10 is each shown by x mark. X marks are each joint (joint point) using welding, mechanical joining or adhesive, or a combination of these, and multiple x signs indicate that there are multiple joint points. Show. Welding uses general-purpose means such as spot welding, TIG, MIG, laser, etc., mechanical joining uses known means such as bolts, nuts, rivets, self-piercing rivets, etc. Adhesive is well-known and commercially available general-purpose adhesive resin is used it can.

  Here, when a load such as the above-described collision is applied to the bracket 10, as described above, the load is intensively applied to the joint portion of the cup bottom 11. On the other hand, the load itself is dispersed at the joint points of the plurality of flanges 13 and 14. Even when there are a plurality of joint points on the cup bottom 11, the joint points are concentrated in a narrower range than the joint points of the flanges 13 and 14, and the moment accompanying the load load (input) is also greater than that of the flanges 13 and 14. Become bigger.

  For this reason, compared with the load (stress) added to the flanges 13 and 14 located in the outer peripheral part side of the bracket 10, the stress which generate | occur | produces in the cup bottom part 11 becomes large. That is, even if the flanges 13 and 14 and the cylindrical vertical wall 12 positioned on the outer peripheral side are made thinner than the cup bottom portion 11 positioned on the inner peripheral side, the influence on the strength characteristics is small. Therefore, these outer peripheral portions can be made thinner as described above, and an efficient weight reduction can be achieved according to the portion to be thickened.

  Furthermore, the bracket 10 of the present invention having a different thickness is advantageous in terms of formability as compared with a conventional bracket formed of a material having the same (constant) plate thickness regardless of the portion. In the case of the differential thickness blank of the present invention, the thickness of the cup bottom 11 that receives a load during press molding is set to be thick, and the thickness of the outer flanges 13 and 14 that become deformation resistance is reduced to thereby reduce the drawing. It is possible to reduce the stress generated at the corner portion of the cup bottom portion 11 (rising portion of the vertical wall 12), which sometimes becomes a breakable danger portion, and to make it difficult to break. That is, the molding limit is higher than in the case of molding from a material having the same thickness regardless of the normal part, and a bracket which is a deeper drawn product can be formed.

  On the other hand, the bracket 20 shown as a comparative example in FIG. 7 is a case where an aluminum alloy extruded shape is used as it is as a bracket, and if only the cross-sectional shape is seen, the bottom portion 21 is thickened (differential thickness). Thus, it is similar to the bracket 10 of the present invention. However, the bracket 20 has a restriction unique to the extruded shape such as a uniform (constant) cross section in the longitudinal direction. For this reason, as can be seen from FIG. 7, the vertical walls 23 and 24 including the thin flanges 22 and 22 on both sides and the thick bottom portion 21, which respectively constitute the brackets 20, are also only in two-dimensional directions. Not extended.

  As a result, the load direction indicated by the arrow F from above in FIG. 7 is a two-dimensional cross section, and the vertical walls 23 and 24 fall relatively easily. Become weaker. For this reason, in order to satisfy the required crushing strength and impact energy absorption performance as a vehicle bumper stay (hereinafter also simply referred to as “stay”), which is one use of the bracket, it is necessary to increase the thickness. The higher the strength required, the higher the weight and the higher the material cost.

Mounting the bracket:
The manner of attaching the bracket of the present invention will be described with reference to FIGS. 6 (a) and 6 (b). FIG. 6A is a plan view showing a case where the differential thickness bracket 10 is a vehicle bumper stay. FIG. 6B is a perspective view showing a joint point (joint location) indicated by a cross mark of the attached differential thickness bracket 10. 6A shows a left side of the bumper reinforcing member 50 whose longitudinal direction extends in the width direction of the vehicle (the left-right direction in the figure) and is inclined symmetrically toward the rear of the vehicle body. Only half is shown partially.

  As shown in FIG. 6, the cup bottom portion 11 of the differential thickness bracket 10 is joined to the rear side wall 52 of the bumper reinforcing member 50 having a rectangular hollow structure at two crosses. On the other hand, the flanges 13 and 14 of the differential thickness bracket 10 are respectively joined to the front side wall 61 of the side frame 60 which is a vehicle structural member at two places (four places in total).

  With respect to such an attachment method, the cup bottom 11 side and the flanges 13 and 14 are opposite to each other, and the flanges 13 and 14 (cup opening 17) side are disposed on the bumper reinforcing material just as shown in FIGS. 50 may be joined to the rear wall side 52 and the cup bottom 11 side may be attached to the side frame tip 61 side.

  Here, when the bracket 10 of the present invention is joined to the same kind of aluminum alloy component, surface treatment such as imparting corrosion resistance is unnecessary. However, when other parts are joined to steel or steel automobile parts, a resin (or a resin that also serves as a joint) is interposed in the joint to prevent electrolytic corrosion due to the potential difference between different materials. It is preferable to insulate aluminum and steel or iron, or to add a surface treatment such as dacro treatment to the steel material.

  As described above, according to the present invention, in view of this point, the present invention can be made thinner and lighter while ensuring the same level of strength and rigidity as the current one, and can be manufactured with excellent moldability and the like. An easy-to-use cup-shaped differential thickness bracket can be provided. Therefore, it is suitable for a bracket that requires energy absorption characteristics such as bumpy stay.

  1: differential thickness blank, 2: central thick part of blank, 3, 4: thin part of blank, 5, 6: each end part in the longitudinal direction of extrusion of the blank, 7, 8: each end part in the width direction of the blank, 10: bracket, 11: cup bottom, 12: cylindrical vertical wall, 13, 14: flange, 15, 16: short vertical wall, 17: opening, 18, 19: end of flange side

Claims (5)

A bracket in which a plate-shaped blank made of an aluminum alloy extruded shape is press-molded, and a cup and a flange connected to the cup are integrated,
The plate-like blank consists of a differential thickness blank having a central thick part and thin parts on both sides in the extrusion direction,
The thick portion of the differential thickness blank is molded at least on the cup, and the thin portion of the differential thickness blank is molded at least on the flange,
The bracket has a cup bottom that is the thickest, a cylindrical vertical wall that rises from the peripheral edge of the cup bottom, an opening surrounded by the vertical wall, and a peripheral edge of the vertical wall. It is constructed integrally with the flange projecting outward from
Joined to other parts at the cup bottom and the flange, respectively.
Difference thickness bracket characterized by that.   The flange of the differential thickness bracket is within the range of 30 ° direction to orthogonal direction and the range of 150 ° direction from the orthogonal direction with respect to the extrusion direction of the plate blank with the center point of the differential thickness bracket as a reference. The differential thickness bracket according to claim 1, wherein the differential thickness bracket is present at least inside.   The flange of the differential thickness bracket does not exist within a range of at least ± 20 ° with respect to the extrusion direction of the plate blank with respect to the center point of the differential thickness bracket. The differential thickness bracket according to claim 1 or 2.   4. The differential thickness bracket according to claim 1, wherein a part of the cylindrical vertical wall of the cup of the differential thickness bracket is cut out. 5.   The difference thickness bracket is a bumper stay for vehicles, the cup bottom is joined to a bumper reinforcement, and the flange is joined to a vehicle structural member, respectively. The differential thickness bracket described.