Hydroformed Metal Pipe Bent Part Expansion
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Solution Overview
Problem
Conventional hydroforming methods cannot effectively produce metal pipe parts with large expansion rates at bent parts, especially in restricted spaces within automobiles, limiting their application in suspension and structural components due to either one-directional expansion or expansion on both sides of the bend, which hinders weight reduction and fuel efficiency.
Innovation Solution
A hydroformed product is created through cold plastic working of metal pipes, featuring a bent part with expansion in one direction and the opposite direction, maintaining a radius of curvature ratio of 50% or less, allowing for increased pipe expansion without expanding on either side of the bend, enabling more complex shapes and improved space utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional hydroforming methods are used to expand metal pipe in one direction or both directions at right angles, then pipe expansion rate increases, but the method cannot be applied to bent parts with large expansion rates in restricted spaces
Solution Approach 1:
The hydroforming process is divided into two sequential stages: first expanding the pipe in one direction to create an intermediate product, then rotating the pipe 90 degrees and expanding it in the perpendicular direction. This segmentation allows each expansion to be controlled independently, enabling large expansion rates at bent parts while maintaining adaptability to restricted spaces.
Solution Approach 2:
The pipe is pre-expanded in one direction before bending, creating an intermediate product with predetermined geometry. This preliminary action prepares the pipe for the second expansion in the perpendicular direction, enabling complex three-dimensional shapes to be achieved in restricted spaces without requiring heat treatment.
2Weight of moving object
If metal pipe is used as straight pipe, then weight reduction is achieved, but auto parts cannot be arranged in narrow spaces
Solution Approach 1:
The pipe expansion process transitions from two-dimensional planar expansion to three-dimensional spatial expansion by performing sequential expansions in perpendicular directions. This dimensional progression enables complex three-dimensional shapes with large expansion rates at bent parts, allowing auto parts to be arranged in narrow spaces while maintaining weight reduction benefits.
3Manufacturing precision
If heat treatment is added to enable large expansion at bent parts, then manufacturing complexity increases, but the patent achieves this without heat treatment
Solution Approach 1:
The hydroforming process continues uninterrupted through two sequential expansion stages without intermediate heat treatment. The pipe material maintains continuous plastic deformation through controlled pressure application in both expansion directions, achieving large expansion rates at bent parts while eliminating the need for additional heat treatment steps and reducing overall process complexity.
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 expands the applicability of hydroforming, enabling lighter automobile components, improved fuel efficiency, and reduced environmental impact by allowing for more complex shapes in restricted spaces without the need for additional heat treatment steps.
Implementation Method 1
cold plastic working of a metal pipe material
Implementation Method 2
fastening a metal pipe in a mold and, in that state, using inside pressure and axial direction compression to work the pipe into the mold shape
Data Source
AI summary
A hydroformed product obtained by integrally working a metal pipe material by cold plastic working, which product (x) has a bent part at least at one location, (y1) has, at least at one location of the bent part, an expanded part of dimensions of a direction toward the outer side (or inner side) of the bend in a cross-section vertical to a pipe axis and a direction vertical to that direction of at least 1.35× of a circle equivalent diameter of an end of the metal pipe, and (z1) has an inner side (outer side) of the bent part of substantially the same radius of curvature.