Twist Axle Stamped Beam Elliptical Opening
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Solution Overview
Problem
Existing twist beam rear axle suspension systems face challenges in achieving the desired balance of stiffness, as traditional methods like forming a U or V shape and post-shaping heat treating are costly and difficult to implement, and stamped designs with welded brackets can be complex and costly.
Innovation Solution
A twist axle assembly with a stamped twist beam featuring end portions with high torsional stiffness and a middle portion with reduced stiffness, achieved through a U-shaped or elliptical opening in the bottom wall and varying widths, allowing for cost-effective production and efficient absorption of deflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the twist beam is formed by crushing a tube into a U or V shape with post-shaping heat treating, then the desired stiffness distribution is achieved, but the manufacturing cost and process complexity increase
Solution Approach 1:
The patent applies parameter changes by modifying the cross-sectional geometry of the twist beam through stamping operations. The beam is stamped to create a C-shaped cross-section with varying wall thicknesses - thicker walls at the ends for higher stiffness and thinner walls in the middle for lower stiffness. This geometric parameter modification achieves the desired stiffness distribution without requiring complex heat treating processes, thereby reducing manufacturing cost and process complexity while maintaining the strength characteristics.
2Strength
If brackets are welded to the longitudinal ends of the stamped twist beam, then the end portions gain increased stiffness, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the function of separate brackets into the twist beam itself by integrating stiffening elements directly into the beam structure. The stamped C-shaped cross-section with varying wall thickness inherently provides the required stiffness at the end portions without requiring additional bracket components. This integration eliminates separate parts and assembly steps, reducing device complexity and manufacturing cost while maintaining the stiffness enhancement at the ends.
3Ease of manufacture
If the twist beam has uniform stiffness throughout, then manufacturing is simpler, but the connections at the end portions are vulnerable to damage from twisting
Solution Approach 1:
The patent applies local quality by creating non-uniform wall thickness distribution in the stamped twist beam. The ends of the beam have thicker walls that provide higher local stiffness to protect connections from twisting damage, while the middle section has thinner walls that allow greater flexibility and deflection absorption. This localized variation in geometric quality enables the beam to simultaneously protect connections and absorb deflection, improving reliability without significantly complicating manufacturing.
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 assembly effectively absorbs deflection in the middle portion, protecting connections between the end portions and trailing arms from damage while maintaining structural integrity and reducing torsional stiffness, thus enhancing ride comfort and durability.
Implementation Method 1
The middle portion has an opening with a generally elliptical shape formed into the bottom wall for reducing a torsion stiffness of the middle portion of the twist beam in comparison to the end portions
Implementation Method 2
During operation of the vehicle, the twist beam deforms in a twisting movement when one of the wheels moves relative to another, such as during vehicle body roll or when one of the wheels encounters, for example, a pothole or an obstacle in a road. The twisting movement of the twist beam absorbs this movement to make the ride more comfortable for occupants in the vehicle body
Data Source
AI summary
The twist axle assembly includes a pair of spaced apart trailing arms and a twist beam which is made of a single piece and is operably connected with the trailing arms. The twist beam has a top wall, a bottom wall and a pair of side walls. The twist beam presents a pair of end portions which are bent to present edges that face towards one another when viewed in cross-section, and the twist beam presents a middle portion which extends between the end portions. The middle portion has an opening with a generally elliptical shape formed into the bottom wall for reducing a torsion stiffness of the middle portion of the twist beam in comparison to the end portions.