Press-moulded Vehicle Lower Arm Groove Formation
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Solution Overview
Problem
Conventional methods for producing press-formed automobile lower arms often result in rupture during stretch flanging deformation, particularly due to insufficient stress concentration dispersion and material inflow issues in the stretch flanging deformation part, leading to reduced productivity and product strength.
Innovation Solution
A method involving a two-step press-working process where the groove part is formed differently in each step, with the first step focusing on forming the vertical wall part without the groove on the second end part side and the second step forming the groove part and remaining vertical wall parts, optimizing material flow to reduce stretch flanging deformation and prevent rupture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a groove part is provided on the second end part side from the bent part in the first step, then material inflow to the stretch flanging deformation part is reduced, but rupture occurs in the stretch flanging deformation part
Solution Approach 1:
The groove part formation is segmented into two steps: the first step forms the groove part on the first end part side from the bent part, while the second step forms the groove part on the second end part side from the bent part. This segmentation allows controlled material flow in each step, preventing rupture by avoiding excessive material inflow that would occur if the entire groove part were formed in a single step.
Solution Approach 2:
The groove part on the first end part side is formed preliminarily in the first step before forming the groove part on the second end part side. This preliminary action prepares the material flow path and reduces stress concentration, enabling successful formation of the remaining groove part in the second step without causing rupture.
2Productivity
If the groove part is formed in a single step, then productivity is improved, but stress concentration is insufficiently dispersed leading to rupture
Solution Approach 1:
The groove part formation process is divided into two sequential steps, each forming a portion of the groove part. This segmentation disperses the stress concentration that would occur in a single-step process, while still maintaining relatively high productivity by completing the formation in only two steps rather than requiring multiple iterative corrections.
Solution Approach 2:
The first step forms the groove part partially (only on the first end part side from the bent part) rather than completing the entire groove part. This partial action allows stress to be dispersed more effectively, and the remaining portion is completed in the second step, achieving both stress dispersion and productivity.
3Strength
If high-tensile strength steel plates are used, then product strength is improved, but formability during press-working is reduced
Solution Approach 1:
The press-working process is segmented into two steps, each forming a portion of the groove part. This segmentation reduces the instantaneous deformation demand on high-tensile strength steel plates, improving formability while maintaining the ability to achieve high final product strength. The two-step process allows the material to deform more gradually without exceeding its formability limits.
Solution Approach 2:
Each step forms only a partial groove part rather than the complete groove part in one action. This partial action reduces the deformation intensity in each step, making it feasible to work with high-tensile strength steel plates that have limited formability, while still achieving the desired final shape and strength properties.
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 effectively reduces stretch flanging deformation and suppresses rupture in the stretch flanging deformation part, enabling the production of a high-strength press-formed product with increased forming height and design flexibility, even with high-tensile strength steel plates.
Implementation Method 1
by applying press-working to a blank metal plate 21, a surface shape on a second end part 11b side from a bent part in a surface shape of a top plate part 13a is formed, and furthermore, the vertical wall part 14a extending from a first end part 11a side of the main body part 11 to the protruded part 12 is formed
Data Source
Figure 1
Figure 2~3A
Figure 3B~3C
AI summary
A press-formed product (10) includes a main body part (11) having a first end part (11a) and a second end part (11b) respectively on both ends, and a protruded part (12) that protrudes outward of bending from a bent part of the main body part (11). On a surface of the top plate part (13a) of the main body part (11), a groove part (15) is provided in a domain on the first end part (11a) side from a root of the protruded part (12). A first vertical wall part (14a) extending from the first end part (11a) of the main body part (11) to the protruded part (12) has a corner part (16) connecting the main body part (11) and the protruded part (12). An angle that is formed by a part which is on the main body part (11) side from the corner part (16) and a part which is on the protruded part (12) side from the corner part (16) is an acute angle. A method for producing the press-formed product (10) includes a first step of forming the first vertical wall part (14a) without forming a shape of the groove part (15) in a surface shape of the top plate part (13a), and a second step of forming the shape of the groove part (15) in the surface shape of the top plate part (13a).