Metal deforming – Process – Tube making or reshaping
Reexamination Certificate
1999-10-15
2001-07-24
Tolan, Ed (Department: 3725)
Metal deforming
Process
Tube making or reshaping
C072S370100, C029S888092
Reexamination Certificate
active
06263720
ABSTRACT:
The instant invention pertains to the plastic deformation forming of metals, and concerns a manufacturing process for wing-shaped metal parts by way of plastic deformation of a tubular part, as well as parts resulting from this process.
The wing-shaped metal parts are normally used in mechanical assemblies and more particularly in the assembly of automobiles.
For the purposes of the instant request, the term wing-shaped parts designates U-shaped or fork links types of parts used to support a pin. It also designates, in a more general manner, parts consisting of wings, i.e. parts whose shapes are more or less elongated or streamlined, manufactured or affixed to a base, wings which are not necessarily parallel to each other, and whose function may be something quite other than supporting a pin i.e. each wing having its own function.
These wing-shaped components may be manufactured on all kinds of parts. The invention concerns the manufacturing of such wing-shaped parts as integral components of a tube extremity, the wings and tube extremity forming one and same component.
Patent GB 2,197,051 describes such a wing-shaped fork link part for a universal joint obtained by way of sheet metal stamping, the central section of the fork link forming a collar with teeth on the inside, for slide mounting on a steering shaft. In this case, the fork link is not merged with a tube-shaped part.
One can contemplate, in other cases, to weld fork links, but this technique has several drawbacks, namely the need to supply separately tube-shaped and U-shaped parts, and to oversee the resulting merchandise stocks, and the presence of welded joints which constitute preferential crack areas in the case of parts subject to fatigue stresses. These welded joints, therefore, require to be inspected, and their presence is not desired in safety parts.
We are aware of U-shaped or fork links merged with tubular parts; patent FR 2,392,838 describes tubular semi-axles for vehicles, but does not describe the manner for making such parts.
We are also aware of tubular parts in the shape of wings whose extremities were split and pulled apart so as to form separate branches.
Hence, the French patent application FR 2,734,207 described a semi-rigid axle for vehicles consisting of a tube whose extremities are split and then pulled apart at an angle lesser than 180° to form two branches in the shape of Y.
We are also aware of similar parts, such as those described in the French patent application FR 2,737,177, consisting of forward or rear subframes for vehicle undercarriages.
The range of manufacturing, described in document FR 2,734,207, consists in making on the extremity of the tubular part longitudinal slits and then to flare the tongues obtained to form wings and to finish the part.
The instant invention has as purpose the manufacturing of parts in the shape of wings, allowing to avoid the problems encountered with prior techniques in which the wings are assembled, such as with welding, onto a base component.
In the instant invention, it was sought to create a particularly effective process with regard to productivity and cost for implementation.
We also sought to improve the existing manufacturing process for wing-shaped parts made of tubes, especially the process described in documents FR 2,734,207 and FR 2,737,177, it being understood that the process for the invention is in no way limited to the applications and scope described in these two documents.
In accordance with the invention, the process for manufacturing metal parts in the shape of wings consists in taking a tube portion and realizing on the extremities of the tube portion the following successive operations:
flattening of an area of the extremity of a tube portion over a certain length, so as to shape two longitudinal beads projecting toward the outside by folding over as a hair pin from the wall of the tube portion;
cutting out of the beads obtained in the preceding operation so as to obtain at least two tongues, separated in a longitudinal manner;
spreading away of the tongues from the body of the tube to constitute wings and shape the latter;
these wings may essentially undergo finishing, before or after shaping.
By tube portion is understood any portion of a tube of which the method of manufacturing, length, radial dimensions, cross-section and nature of the material are adapted to the wing-shaped part to be manufactured. In particular, this tube does not necessarily have a constant cross-section or thickness over its entire length, and its cross-section is not necessarily a revolving one. Steel or any other metal may be used.
Preferentially, the flattening of an area of the extremity of the tube portion so as to shape at least two longitudinal beads shall be conducted by way of unsupported deformation without using a mandrel or inside tube support, and, as a great advantage, the flattening shall be conducted via compression between two dies of which the shape allows for at least supporting the outside wall of the tube between the beads.
As an advantage, the cutting of the beads shall be done by way of shearing off.
As an advantage, the longitudinal beads formed at the extremity of the tube portion shall number two, the part obtained, therefore, consisting of two wings. In the case of a revolution tube portion, these two beads shall preferably be positioned symmetrically with regard to the axis of the extremity of the tube portion.
It should be noted that, in general, the cutting of the beads will not require any inside tooling of the tube portion, thus facilitating the shaping operation following the cutting.
The tongues obtained at the extremity of the tube portion following the bead cutting show curvature or counter-curvature arising from the rest of the beads at the level of their lateral edges and from the initial shape of the tube cross-section. These curvatures or counter-curvatures may be kept, whole or in part, or eliminated, whole or in part, during the shaping and/or finishing operations of the wings.
The shaping of the wings is an operation of plastic deformation allowing to give to the obtained tongues, following the cutting operation, their final and desired shape. It may be done by any known means, in one or several operations, and, for example by splaying or spacing inside shaping dies with a punch-type tool.
The finishing operations are proper to each part.
The overall operations in accordance with the invention process may be repeated at the other extremity of the tube portion should it be required to shape a part with wings at both ends.
The curvature obtained at the stage of cutting the beads allows to increase the inertia module of the wings and, therefore, to render them rigid in longitudinal deflection and twisting. It would, therefore, be advantageous to preserve that curvature for certain applications.
Such wings can, however, be deformed longitudinally, namely by way of bending, without the risk of tearing the most elongated areas as long as they are almost flat, transversally.
The invention has the advantage of making parts consisting of two parallel wings at the extremity of the tube portion.
In this case, the flattening of the extremity of the tube portion is done so as to form two opposed beads, and the tongues obtained after cutting are spread parallel to the axis of the tube portion while being shaped, so as to form two parallel wings at a distance from each other, wings which can, for example, be flat.
As an advantage, the shaped wings can be pierced across from each other during the finishing operation to allow to lodge a perpendicular yoke pin at the level of the wings and hence form a fork link.
The invention also allows, as an advantage, to manufacture parts consisting of two Y-shaped wings at the extremity of a tube portion.
In this case, after flattening the beads and cutting them, the operation for shaping the wings is done with a punch spreading the tongues out of the tube portion and eliminating, or leaving, the transverse curvature of the tongues after cutting.
The dihedral angle formed by the wings at
Jacobson Price Holman & Stern PLLC
Tolan Ed
Vallourec Composants Automobiles Vitry
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