Center Pillar Reinforcement Forming via Segmented Press-Forming
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Solution Overview
Problem
The existing methods for producing center pillar reinforcements by press-forming face challenges such as wrinkles and cracks in the top sheet and flanges, requiring high-strength materials that increase the weight and cost of the automobile body shell, and often necessitate the use of multiple components due to the complex shape and strength requirements.
Innovation Solution
A method involving two steps of press-forming using a first device for shallow drawing and a second device for bend-forming, with a tailored blank of high-tensile steel, where the blank is shaped to reduce vertical wall heights and use a pad and punch to clamp and form the T shape sections, avoiding material flow issues that lead to wrinkles and cracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If drawing press-forming is used to produce center pillar reinforcement, then the complex shape with high strength can be achieved, but the blank requires very high extensibility which limits material selection and increases weight
Solution Approach 1:
The forming process is segmented into two distinct stages: first forming the body portion with hat-shaped cross section, then separately forming the T-shaped end portions. This segmentation allows each stage to be optimized independently, enabling the use of high-tensile steel blanks that would be unsuitable for single-stage drawing press-forming.
Solution Approach 2:
The body portion is preliminarily formed into an intermediate product with reduced vertical wall heights before the final forming of T-shaped end portions. This preliminary action prepares the blank in a state that facilitates subsequent forming without causing wrinkles or cracks, enabling the use of materials with lower extensibility.
2Strength
If high-strength steel blank is used to ensure required strength, then the structural integrity is improved, but wrinkles and cracks occur on top sheet and flanges during press-forming
Solution Approach 1:
The forming process is divided into two stages where the high-strength blank is first formed into an intermediate product with controlled geometry, then subsequently formed into the final shape. This segmentation prevents excessive material flow and stress concentration that would cause wrinkles and cracks in single-stage forming.
Solution Approach 2:
The vertical wall heights are reduced in the intermediate product compared to the final product. This parameter change in the intermediate stage allows high-strength material to be formed without exceeding its ductility limits, while the final product achieves the required dimensions and surface quality.
3Strength
If thick and heavy blank is used to ensure high strength with low-extensibility material, then the strength requirement is met, but the weight of automobile body shell increases
Solution Approach 1:
The forming process utilizes controlled parameter changes through two stages, allowing the use of thinner blanks with high-tensile strength properties. The intermediate product geometry optimization enables efficient material distribution that achieves required strength with reduced weight compared to traditional single-stage forming.
4Device complexity
If single-stage drawing press-forming is used, then the production process is simple, but the blank requires wide margin thickness due to strong restraint by blank holder
Solution Approach 1:
The forming process is segmented into two stages, with the first stage forming the body portion and the second stage forming the T-shaped end portions. This segmentation reduces the restraint intensity in each stage compared to single-stage forming, allowing narrower blank margins and reduced material waste.
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 method allows for the production of center pillar reinforcements with high strength and complex shapes at a lower cost without wrinkles or cracks, using high-tensile steel blanks, thereby reducing weight and production costs while maintaining structural integrity.
Implementation Method 1
press-forming a blank, which is a sheet metal such as a steel sheet
Data Source
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AI summary
A center pillar reinforcement is produced satisfactorily by using a high-tensile material having a low ductility as a blank. The center pillar reinforcement is produced by performing a first step for producing a first intermediate formed product on which a body is partially formed by press-forming the blank using a first press-forming device for drawing, and a second step for pressing the first intermediate formed product by using a second press-forming device for bend-forming.