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AssigneeForschungsgesellschaft Umformtechnik mbH
InventorsAribert Schwager, Fritz Bley, Manfred Kammerer, Klaus Siegert
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The invention relates to a method and an apparatus for producing a workpiece with internal toothing, especially an internal geared wheel, by using a cup-like preform (N) with a substantially cylindrical side wall (N1) and a mandrel (5) with an external profile (6) according to the internal toothing to be produced, as well as with a forming tool which reduces the outside diameter of the cylindrical side wall during an advancing movement, as a result of which the material of the cylinder wall region flows into the external profile (6) of the mandrel (5). In accordance with the invention, the forming tool is configured as a drawing ring (14) ensuring the ironing of the cylinder wall region (N1) during an advancing movement and that two tool elements act upon the preform (N) during the ironing, which tool elements produce axial compressive stresses in the cylinder wall region (N1) of the preform. In accordance with the method, the reduction of the outside diameter occurs by ironing by means of a drawing ring and that during the ironing additional axial compressive stresses are applied onto the cylindrical side wall of the preform.
An apparatus for producing a workpiece with internal toothing, especially an internal geared wheel, by using a cup-like preform (N) with a substantially cylindrical side wall (N1) and a mandrel (5) with an external profile (6) according to the internal toothing to be produced, as well as with a forming tool which reduces the outside diameter of the cylindrical side wall during an advancing movement, as a result of which the material of the cylinder wall region flows into the external profile (6) of the mandrel (5), characterized in that the forming tool is configured as a drawing ring (14) ensuring the ironing of the cylinder wall region (N1) during an advancing movement and that two tool elements act upon the preform (N) during the ironing, which tool elements produce axial compressive stresses in the cylinder wall region (N1) of the preform.
A method for producing a workpiece with an internal toothing, with a cup-like pre-form with a floor and a substantially cylindrical side wall is reduced in its outside diameter by means of a mandrel which comprises the outside profile according to the inner toothing to be produced, so that the material of the cylinder wall region flows into the outside profile of the mandrel, characterized in that the reduction of the outside diameter occurs by ironing by means of a drawing ring and that during the ironing additional axial compressive stresses are applied onto the cylindrical side wall of the preform.
Dependencies are inferred from the claim text.