Hollow Stabilizer Bending to Limit Bent-Part Flatness
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Solution Overview
Problem
Conventional methods for forming a hollow stabilizer using a die result in excessive flatness and stress distribution variation in the bent part, leading to potential interference with surrounding parts and increased stress peaks.
Innovation Solution
A stabilizer manufacturing device comprising a base die, clamp die, pressing die, and moving die is used to form a hollow stabilizer with specific cross-sectional parts, each having varying curvatures to minimize flatness and stress distribution variation, utilizing a heating step and bending process to achieve a cross section close to a perfect circle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional die is used to bend the pipe in the radial direction, then the bent part can be formed, but the cross section of the bent part becomes flat with large flatness exceeding the allowable range
Solution Approach 1:
The patent introduces a new bending dimension by positioning the pipe vertically and bending it in the axial direction rather than the conventional radial direction. The pipe is clamped in a vertical state, and the bending die applies force from the top to form the bent part along the pipe's length, transforming the bending operation from a horizontal radial process to a vertical axial process. This dimensional change prevents the cross-section from flattening while achieving the required bend.
Solution Approach 2:
The patent applies preliminary heating to the pipe before bending to reduce its rigidity and make it more pliable. By heating the pipe to a temperature where its material properties become more ductile, the subsequent bending operation can be performed with less force and without causing excessive flattening of the cross-section. This preliminary thermal preparation enables precise control of the bending process.
2Volume of moving object
If the pipe is bent with a small radius of curvature at a right angle, then the stabilizer can achieve compact design, but the flatness of the bent part increases significantly
Solution Approach 1:
By changing the bending direction from radial to axial and positioning the pipe vertically, the patent enables formation of tight-radius bends without cross-sectional flattening. The vertical orientation allows the pipe to bend along its length rather than across its section, achieving compact configurations with small radii of curvature while maintaining circular cross-sections within the allowable flatness range.
Solution Approach 2:
The patent changes the physical state of the pipe material through heating, transitioning it from a rigid state to a more ductile state. This parameter change in temperature and material properties enables the pipe to accommodate small radius bends without resistance, allowing compact stabilizer design while preventing cross-sectional distortion that would occur with cold bending.
3Manufacturing precision
If a pipe bender with pipe clamp is used, then the bent part flatness can be controlled, but the distance from the distal end of the arm part to the bent part becomes too long
Solution Approach 1:
The patent applies preliminary heating to the pipe section that will be bent, making the material more ductile and easier to form. This thermal preparation allows the bending operation to be performed on a shorter pipe section without requiring the extended grip length that a pipe clamp would need, thereby reducing the distance from the arm part distal end to the bent part while still achieving controlled flatness.
Solution Approach 2:
The patent replaces the mechanical pipe clamp gripping system with a thermal softening approach. Instead of using a mechanical clamp that requires a certain grip length to prevent slipping and maintain control, the heated pipe material itself becomes more compliant, allowing the bending die to form tight-radius bends on shorter sections without requiring extended clamp engagement lengths.
4Ease of manufacture
If the bent part has large flatness, then the manufacturing process is simpler, but the stress distribution in the bent part becomes uneven with increased peak stress
Solution Approach 1:
By bending the pipe in the axial direction rather than radially, the patent achieves a more uniform stress distribution throughout the bent part. The axial bending method distributes the applied force along the length of the pipe rather than concentrating it at a single radial point, resulting in more homogeneous plastic deformation and reduced peak stress concentrations while maintaining manufacturing feasibility.
Solution Approach 2:
The patent uses temperature as a controlling parameter to modify the pipe material's flow stress characteristics. By heating the pipe to an elevated temperature, the material exhibits more uniform plastic deformation behavior during bending, which promotes even stress distribution throughout the bent section and prevents localized stress peaks that would occur with cold bending.
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
The solution effectively suppresses flatness to within ±10% of the pipe diameter and reduces stress distribution variation, enhancing durability and minimizing peak stress, particularly on the inner surface, thus improving the performance and reliability of the hollow stabilizer.
Implementation Method 1
a heating step, a placing step, and a bending step. The heating step heats the pipe that is a material of the hollow stabilizer to a warm region.
Implementation Method 2
a bending step. The bending step forms the bent part by bending the pipe with a moving die in a state where crushing the part that is to be the bent part of the pipe in a flat shape is restricted
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A hollow stabilizer disposed in a vehicle suspension mechanism part comprises a torsion part (20); a bent part (21, 22) continuous with the torsion part (20); and an arm part (23, 24) continuous with the bent part (21, 22), and including, when a center of bending inside is 0° and a center of bending outside is 180° in a cross section in a pipe radial direction of the bent part (21, 22), eight regions (S1 to S8) defined in a circumferential direction of the cross section.