Patent Application
20140326351
Extruded aluminum pieces are used in various implementations, for example as structural vehicle components designed to absorb impact energy (e.g., in a crash). However, achieving a controlled collapse can be difficult, for example because the extrusion is usually prismatic in nature. Forming the piece by another technique than extrusion (e.g., by fabricating it from sheet metal) does not provide the material properties of extrusion.
In a first aspect, a method includes: determining a design for a longitudinal piece of a particular length, wherein first and second ends of the longitudinal piece have dissimilar shapes; extruding a piece that is at least twice the particular length, wherein a profile throughout the extruded piece has the first end shape; hydroforming the extruded piece to generate an expanded portion between ends of the extruded piece, wherein the ends retain essentially the first end shape; and cutting through the expanded portion to obtain a piece wherein one end has the first end shape and another end has the second end shape.
Implementations can include any or all of the following features. The first end shape is chosen for the design to be a folded version of the second end shape. A perimeter of the first end shape is substantially the same as a perimeter of the second end shape. The first end shape comprises two rounded portions joined by a waist. The second end shape comprises an oval. Hydroforming the extruded piece comprises pre-stretching the other end having the second end shape. The piece is extruded from aluminum or an aluminum alloy.
In a second aspect, a longitudinal piece includes: a first end having a first end shape; and a second end a having a second end shape dissimilar from the first end shape, wherein the second end shape is obtained by cutting through an expanded portion generated by hydroforming an intermediate portion of an extruded piece that initially has a profile corresponding to the first end shape.
Implementations can include any or all of the following features. The first end shape is chosen for the design to be a folded version of the second end shape. A perimeter of the first end shape is substantially the same as a perimeter of the second end shape. The first end shape comprises two rounded portions joined by a waist. The second end shape comprises an oval. Hydroforming the extruded piece comprises pre-stretching the other end having the second end shape. The piece is extruded from aluminum or an aluminum alloy.
This document describes systems and techniques for using extrusion and hydroforming to create a piece that has a desired design and the material properties of an extrusion. For example, a piece can be extruded from aluminum to have a certain profile throughout its length, and this piece can then be placed in a hydroformer where the pressure causes a center section of the piece to bulge out. When removed from the hydroformer, the shaped piece can be cut apart (e.g., at the middle) so that the bulging section creates a desired end profile at one end of each of the pieces, wherein the other end has substantially the same profile as when extruded.
Here, a center portion 110 of the hydroformed piece 100 bulges out compared to the rest of the piece. Particularly, the center portion has a profile that is desirable as an end shape of a design. The hydroformed piece can therefore be cut apart—e.g., severed at the middle using a saw or other blade) to form respective pieces 112 as shown in
Each of the pieces 112 has the desired design 102. That is, each of the pieces 112 has a first end with the extruded profile (e.g., the rounded portions 106 joined by the waist 108) and a second end with a desired profile 114. In this example, the desired profile is essentially an oval shape. The oval can provide additional stability (e.g., during a process of controlled collapse, such as in a crash). In some implementations, each end of the piece 112 is mounted onto an end block that substantially corresponds to its shape. For example, the first end can attach to the front bumper of a vehicle and the second end can attach to a structure further back in the vehicle (e.g., a torque box).
Here, an extrusion piece 206 is clamped in the hydroformer 200. That is, a first end 208A of the extrusion piece is clamped by one end of the hydroformer, the body of the extrusion piece extends through the internal cavity 204, and a second end 208B of the extrusion piece is clamped by another end of the hydroformer. Components 210 that enclose the ends of the extrusion piece indicate that the ends are sealed and that a liquid under pressure (e.g., water) can be injected into the extrusion piece.
Suppose now that liquid is injected into the extrusion piece using the component(s) 210. Assuming that the pressure is strong enough, the liquid will deform the extruded aluminum to some extent.
Referring again to
In the above examples, a hydroformed extrusion piece was described where a first end had a profile of two rounded portions joined by a waist, and the second end was essentially oval. In some implementations, one or more other shapes can be used for the first and/or second end. As another example, hydroforming can be performed using a suitable liquid other than water, including, but not limited to, oil.
A number of implementations have been described as examples. Nevertheless, other implementations are covered by the following claims.
