Method for producing sheet metal part and a forming tool

Abstract

In a method for producing a sheet metal part, a sheet metal blank is rolled to have at least two regions of different material thickness to define a thick region and a thin region, with a thickness profile of the sheet metal blank extending in substantial symmetric relationship to a central plane of the sheet metal blank. The sheet metal blank is inserted into a forming tool having a punch and a die and a punch-proximal side of the sheet metal blank is contacted with a pressing cam formed on the punch. The sheet metal blank is formed into the sheet metal part by pressing the punch against the die and thereby forming an embossment by a die cam provided on the die on a die-proximal side of the sheet metal part.

1 . A method for producing a sheet metal part, comprising:
 rolling a sheet metal blank to have at least two regions of different material thickness to define a thick region and a thin region, with a thickness profile of the sheet metal blank extending in substantial symmetric relationship to a central plane of the sheet metal blank;   inserting the sheet metal blank into a forming tool having a punch and a die;   contacting a punch-proximal side of the sheet metal blank with a pressing cam formed on the punch; and   forming the sheet metal blank into a sheet metal part by pressing the punch against the die and thereby forming an embossment by a die cam provided on the die on a die-proximal side of the sheet metal part.   
     
     
         2 . The method of  claim 1 , wherein the sheet metal part has a section which extends from the pressing cam in a direction of an edge of the sheet metal part and is in complete contact with the punch in a closed state of the forming tool, with the die having opposite to the section a hollow space formed at least in an area between the die and the die-proximal side of the sheet metal part. 
     
     
         3 . The method of  claim 1 , wherein the sheet metal part has a section which extends from the die cam in a direction of an edge of the sheet metal part and is in complete contact with the die in a closed state of the forming tool, with the punch-proximal side of the sheet metal part having opposite to the section a hollow space formed at least in an area between the punch and the punch-proximal side of the sheet metal part. 
     
     
         4 . The method of  claim 1 , wherein the forming step is executed by a hot forming tool. 
     
     
         5 . The method of  claim 4 , wherein the formed sheet metal part is press hardened in the forming tool by quenching. 
     
     
         6 . The method of  claim 1 , wherein when forming the sheet metal blank into the sheet metal part, a waveform is formed on the sheet metal part in a cross sectional direction of the sheet metal part as a result of an offset of the die cam relative to the pressing cam. 
     
     
         7 . The method of  claim 1 , wherein a first embossment is formed on the die-proximal side of the sheet metal part and a second embossment is formed on the punch-proximal side of the sheet metal part, and wherein the first and second embossments have an embossment offset relative to one another as a result of the offset of the die cam relative to the pressing cam. 
     
     
         8 . The method of  claim 1 , wherein the sheet metal blank has a material thickness between 0.5 mm and 5 mm. 
     
     
         9 . The method of  claim 1 , wherein the sheet metal blank has a material thickness between 0.8 mm and 3.5 mm. 
     
     
         10 . The method of  claim 1 , wherein the sheet metal blank has a material thickness between 1.2 mm and 2.2 mm. 
     
     
         11 . The method of  claim 1 , wherein the rolling step is executed to realize a rolling reduction of the sheet metal blank of maximally 50% of a material thickness of the sheet metal blank. 
     
     
         12 . The method of  claim 1 , wherein the embossment has a cross sectional width of at least 0.75 times a thickness of the thin region. 
     
     
         13 . The method of  claim 1 , further comprising joining the sheet metal part to another part by a joining process selected from the group consisting of material joint, force fit, and formfit. 
     
     
         14 . The method of  claim 7 , wherein the die cam and/or pressing cam is positioned such that the first and second embossments are formed in a region of the sheet metal part which is not used for joining. 
     
     
         15 . A forming tool for forming of a rolled sheet metal blank into a sheet metal part, comprising
 a punch; and   a die,   wherein at least one member selected from the group consisting the punch and the die has a cam disposed in a transitional thickness region of the rolled sheet metal blank, and   wherein in a closed state of the forming tool, a hollow space is formed at least in an area on a side opposite the cam between the sheet metal part and the member.   
     
     
         16 . The forming tool of  claim 15 , wherein the transitional thickness region extends between a thick region and a thin region of the sheet metal blank, said cam having a thickness which essentially corresponds to a thickness of the thick region less a thickness of the transitional region at a position of the cam. 
     
     
         17 . The forming tool according to  claim 15 , constructed as a hot forming tool.