Method and apparatus for hydro-forming an elongated tubular member
AssigneeFord Global Technologies, LLC
InventorSergey Fedorovich Golovashchenko
Life of this patent
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Abstract
A method of hydro-forming an elongated tubular member that has areas of predicted high strain and areas of predicted low strain. The tubular member is initially deformed into a preliminary preform shape by compression in a preform die. Metal in the areas of predicted low strain is stretched during the preforming process by radially deforming the tube between two halves of the preform die. The preliminary preform is then expanded with internal hydro-forming pressure to form a preformed tube. The preformed tube is then hydro-formed into a final die to form the final shape for the part. The extra metal in the areas of low strain is stretched into the areas of high strain in the final hydro-forming operation.
Claims16
A method of hydro-forming an elongated tubular member that has areas of predicted high strain and areas of predicted low strain, comprising:
- stretching the tube by deforming the tube radially in the areas of predicted low strain in to a preliminary preform in a preform die;
- hydro-forming the preliminary preform in a first hydro-forming operation into a preformed tube;
- and
- hydro-forming the preformed tube in a second hydro-forming operation in a final die into a final shape.
A method of hydro-forming a tubular part to have at least one corner that is to be formed in a corner area extending in a lengthwise direction relative to the tubular part, the tubular part having a width as measured between two opposed sides of Wmin in a minimum width area and of Wmax in a maximum width area, the method comprising the steps of:
- selecting a metal tube that has a circular cross-section with a diameter D that is greater than Wmin;
- forming the tube in a preform die to mechanically compress the outer diameter of the tube in at least one localized area that extends lengthwise along the tube and is adjacent to the corner area to form a preliminary preform, wherein the outer surface of the tube is compressed to less than Wmin;
- hydro-forming the preliminary preform in a first hydro-forming operation in the preform die to form a preformed tube;
- removing the preformed tube from the preform die;
- loading the preformed tube into a final die;
- and
- hydro-forming the preformed tube in a second hydro-forming operation in the final die to form the corner in the tube.
A method of designing a set of dies for hydro-forming a tube comprising:
- developing a model of a final part to collect data corresponding to the distribution of strains in the tube after forming in a theoretical single step hydro-forming process;
- identifying in the model predicted under-stretched areas and predicted over-stretched areas that are expected to be formed during the theoretical single step hydro-forming process;
- designing a preforming die set based upon the model to provide stretching of the predicted under-stretched areas to the designated level of strain;
- and
- designing a final hydro-forming die set based upon the model in which the extra metal in the predicted under-stretched areas of the tube is drawn into predicted over-stretched areas.
Dependencies are inferred from the claim text.