Closed Structure Parts Manufacturing Using Integrated Hemming and Press Forming
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Solution Overview
Problem
The manufacturing of closed structure parts with a closed section, such as vehicle side members or doors, often results in increased weight due to the number of sub-parts and the weight ratio of flange portions, necessitating a method to reduce the number of sub-parts and manufacturing steps while maintaining structural integrity.
Innovation Solution
A press forming method using a single metal plate with pre-hemming and hemming prongs, where the flange portions are brought closer using insert guide surfaces and slit clearances in the press forming die, allowing for simultaneous hemming and press forming, reducing the number of sub-parts and manufacturing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If multiple press sub-parts are assembled to form a closed structure part, then the structural integrity and closed section are achieved, but the weight of the closed structure part increases due to the cumulative weight of flange portions
Solution Approach 1:
The patent merges multiple press sub-parts into a single integrated press part by forming flange portions directly on the press part body through press forming. This eliminates the need for separate flange components and their associated joining operations, thereby reducing the total weight while maintaining structural integrity through the integrated design
2Strength
If multiple press sub-parts are used to create a closed structure part, then the closed section is formed, but the number of manufacturing steps increases due to multiple press forming operations and assembly steps
Solution Approach 1:
The patent combines multiple manufacturing operations into a single press forming process. The flange portions are formed integrally with the press part body in one pressing operation, eliminating the need for separate flange attachment steps and reducing the total number of manufacturing operations required to produce the closed structure part
Solution Approach 2:
The patent performs preliminary forming of the flange portions during the main press forming operation. By pre-forming the flange portions as integral parts of the press part body before final assembly, the manufacturing process is streamlined and the number of subsequent assembly steps is reduced
3Ease of manufacture
If flange portions are formed on each press sub-part, then the closed structure part can be assembled, but the weight ratio of flange portions to the entire closed structure part increases
Solution Approach 1:
The patent merges the flange portions with the press part body into a single integrated component. This eliminates the need for separate flange parts and their associated joining hardware, significantly reducing the weight ratio of flange portions to the total closed structure part weight while maintaining assemblability through the integrated design
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 efficiently manufactures lightweight closed structure parts by integrating flange portions and reducing the weight ratio of flange portions, thereby decreasing the overall weight and simplifying the manufacturing process.
Implementation Method 1
urging a pair of insert guide surfaces formed on the press forming die against the top of the flange portion having the hemming prong therein, moving the press forming die in a predetermined pressing direction so that the two flange portions are brought closer to each other due to a force component perpendicular to the pressing direction that is generated by each of the insert guide surfaces
Implementation Method 2
simultaneously bending the hemming prong using a pressing force transferred from an inner surface portion of the slit clearance to a top portion of the hemming prong so that the other flange portion is sandwiched by the hemming prong and the flange portion is fixed to the flange portion
Implementation Method 3
pressing the metal plate using a press forming surface formed outside of each of the insert guide surfaces of the press forming die and press-forming outer portions of the pair of the flange portions of the metal plate into predetermined shapes
Data Source
AI summary
The number of sub-parts of a closed structure part and the number of steps for manufacturing the closed structure part can be reduced and, therefore, the closed structure part can be efficiently manufactured. In a hemming press step, a punch is further lowered, and a pair of flange portions is inserted into a slit clearance. Hemming prongs are bent and each of the hemming prongs sandwiches the flange portion. The flange portion, which is one of the two flange portions, is joined to the other flange portion. At the same time, a pair of press forming surfaces of the punch presses a metal plate and performs press-forming on a pair of shoulder portions of a blank into a predetermined shape. The flange portion can be fixed to the other flange portion using the hemming prongs. The pair of shoulder portions of the blank can be press-formed into the predetermined shape.