Metal deforming – By application of fluent medium – or energy field – With actuated tool engaging work
Patent
1987-04-08
1988-11-08
Larson, Lowell A.
Metal deforming
By application of fluent medium, or energy field
With actuated tool engaging work
72370, B21D 2602
Patent
active
047826797
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The invention relates to a process for the production of flanges or collars on hollow parts, which are internally supported during lateral extrusion.
Flanges shaped onto hollow parts have a large number of different uses, e.g. as flanges on tubes, for hubs and the like.
PRIOR ART
For example, lateral extrusion as a forming process is defined in DIN 8583.
Processes and apparatuses are known for the production of pins or journals according to the lateral extrusion process and this also applies regarding the lateral extrusion of a collar on solid bodies. It is also known to extrude gear wheels, radially movable tool elements being used from the outside to the inside. In lateral extrusion, the material flows radially partly from the outside to the centre of the workpiece and partly outwards from the centre of the workpiece.
Solid block forming of solid steel bodies by lateral extrusion of a collar is e.g. described in the journal Draht, 35, 1984, p 13 ff. DE-AS 10 87 433 discloses the internal supporting by means of a punch during the lateral extrusion of hub bodies, particularly for freewheeling brake hubs.
Hitherto the lateral extrusion of flanges or collars of hollow parts was disadvantageous in that a fold or lap always formed in the interior of the hollow part at the flange formation point. It is admittedly known to avoid such a lap by a combination of two-sided can extrusion and lateral extrusion. A hollow part with a collar or flange can also be produced by perforating the can bottom. However, the hollow part length attainable by such a procedure is dependent on the process-based ratio of length to diameter (up to approximately 4), i.e. it has hitherto only been possible in this way to produce hollow parts with process-based maximum length.
DESCRIPTION OF THE INVENTION
The problem of the invention is to provide a process for the production of hollow parts with a flange or collar, which permits the production of flanges or collars without a lap in the flange or collar region and accompanied by low production costs, whilst there is no process-based restriction of the length of the hollow parts provided with flanges.
In a process of the aforementioned type, this problem is solved in that the material is supported in the bore by a plastically acting medium.
Due to the plastic inner supporting of the hollow part during lateral extrusions, there can surprisingly be a deflection of the laterally flowing material towards the outside without the formation of an inner lap or fold and the flange can be produced in a single process stage.
A variable controlled material flow results from the plastic support. Conventionally produced parts with a collar lap, produced by the inexpensive lateral extrusion process, could only be used for less important purposes, because the lap could not be taken into consideration in strength calculations and simultaneously represented a starting point for cracks on applying a load and the fracture of the component. In the preferred embodiment of the inventive process, a plastically and/or elastically deformable material, e.g. rubber, plastic, soft metal or the like is used for support purposes.
According to another preferred embodiment of the inventive process a gas and preferably a gas under high pressure is used for support purposes.
In a particularly preferred embodiment of the inventive process water is used for support purposes and said water has an elastic behaviour under pressures in the range of up to 10,000 bar.
As a result of the inventive process it is possible to produce both rotationally symmetrical and non-rotationally symmetrical flanges or collars.
The supporting effect can partly be obtained by a mandrel, the plastic material only being used in the flange region for balancing and flow reversal purposes. Forming can take place both at ambient temperature and at higher temperatures.
The process can be used on all materials formable by lateral extrusion and can also form part of per se known other forming processes, e.g. can be used together with re
REFERENCES:
patent: 203842 (1878-05-01), Leland
patent: 2138199 (1938-11-01), Wendel
patent: 2168641 (1939-08-01), Arbogast
patent: 2328742 (1943-09-01), Rogers et al.
patent: 3442106 (1969-05-01), Gray, Jr. et al.
Gesenkschmiede Schneider GmbH
Larson Lowell A.
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