Press-Formed Metal Sheet Layout for Curved Hat Sections
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for press forming vehicle frame components with hat-shaped cross-sectional shapes, particularly those with curved portions, often result in cracks, wrinkles, and dimensional inaccuracies due to material ductility issues and spring-back, which are exacerbated by the use of high tensile strength steel sheets.
Innovation Solution
A press forming method that involves rotating the boundary between curved and linear portions of the metal sheet to balance material distribution, combined with projection portions and bead shapes to manage stress and deformation, ensuring the line lengths of flange and ridge lines align closely with the final component shape, thereby reducing defects and spring-back.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high tensile strength steel sheet is used to achieve vehicle lightweighting and collision safety, then strength is improved, but ductility decreases and spring-back becomes large
Solution Approach 1:
The patent applies preliminary action by providing projection portions and bead shapes on the metal sheet before press forming. These pre-formed features serve as material reservoirs that compensate for material shortage during forming of curved portions, preventing cracks and wrinkles while reducing spring-back in high tensile strength steel sheets
Solution Approach 2:
The patent applies local quality by creating non-uniform thickness distribution through projection portions and bead shapes at specific locations (curved inner sides and outer sides). This local variation in material properties allows different regions of the sheet to have optimized characteristics for their specific forming requirements, preventing defects at critical locations
2Shape
If metal sheet is press formed into component shape with curved portions, then desired geometry is achieved, but cracks occur at flange portion on curved inner side due to material shortage
Solution Approach 1:
The projection portions are formed in advance at locations corresponding to curved inner sides before press forming. These pre-formed projections provide additional material that flows into curved portions during forming, preventing material shortage and crack occurrence while achieving the desired curved geometry
Solution Approach 2:
The projection portions act as intermediary material reservoirs between the flat sheet and the final curved form. They mediate the material flow during forming, ensuring adequate material supply to curved inner sides without requiring changes to the base metal sheet properties
3Shape
If metal sheet is press formed into component shape with curved portions, then desired geometry is achieved, but wrinkles occur at flange portion on curved outer side due to material excess
Solution Approach 1:
Bead shapes are formed in advance at locations corresponding to curved outer sides before press forming. These pre-formed beads control material flow by creating controlled resistance to material movement, preventing material accumulation and wrinkle formation while achieving the desired curved geometry
Solution Approach 2:
The bead shapes modify local material parameters (thickness, stiffness) at curved outer sides. This parameter change creates controlled material flow resistance during forming, preventing excessive material accumulation that would cause wrinkles while maintaining the ability to achieve the target shape
4Shape
If metal sheet is press formed into component shape with curved portions, then desired geometry is achieved, but spring-back and dimensional inaccuracy occur due to stress difference and cross section opening
Solution Approach 1:
Projection portions and bead shapes are formed before press forming to pre-distribute stresses and restrain cross-sectional opening. These pre-formed features create controlled stress distribution patterns that reduce spring-back and maintain dimensional accuracy after forming
Solution Approach 2:
The projection portions and bead shapes modify local mechanical parameters (stiffness, stress distribution) in the metal sheet. These parameter changes create a more uniform stress state during forming, reducing the stress differences that cause spring-back and dimensional inaccuracy
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces the occurrence of cracks, wrinkles, and dimensional inaccuracies in press-formed components, improving the accuracy and reliability of the manufacturing process for vehicle frame components with complex geometries.
Implementation Method 1
a metal sheet for press forming that is press formed into a press-formed component shape
Implementation Method 2
a spring-back or the like exceeding a predetermined amount easily occurs in the formed product after release
Data Source
AI summary
A metal sheet for press forming has a shape such that a boundary position between the region corresponding to the curved portion and an other region in the region corresponding to a curved portion is rotationally displaced in-plane around a rotational center set at a position on a curved recessed side rather than a position corresponding to a ridge line between a top sheet portion and a vertical wall portion on the curved recessed side, in a direction in which a line length of an outer edge of a position to be formed into the flange portion on a curved protruding side in the region corresponding to a curved portion approaches a line length of an outer edge of the flange portion on the curved protruding side in the press-formed component shape.