Eccentric Control-Arm Bushings for Stable Short-Arm Suspension
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Solution Overview
Problem
Existing suspension systems face challenges with vehicle stability due to limited space for control arms, particularly in upper control arms, leading to high instability during bump and rebound phases, and require interchangeable bushings with differential stiffness and compliance for leading and trailing positions.
Innovation Solution
A suspension system using eccentric control arm bushings with non-concentrically aligned inner and outer sleeves, filled with elastomeric material, allowing for pivoting about a virtual pivot axis that extends the effective control arm length and provides differential stiffness and compliance, enabling interchangeable use in leading and trailing positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional concentric bushings are used in short control arms, then the suspension package fits within limited space, but vehicle stability deteriorates due to high roll center migration in bump or rebound conditions
Solution Approach 1:
The bushing design employs asymmetric geometry where the inner sleeve is offset from the center of the outer sleeve, creating an eccentric configuration. This asymmetry allows the control arm pivot point to be positioned such that the effective control arm length is increased, thereby reducing roll center migration and improving vehicle stability while maintaining compact packaging.
2Adaptability or versatility
If different bushings are used for leading and trailing positions, then differential stiffness and compliance are achieved, but device complexity increases due to more parts needed for assembly and maintenance
Solution Approach 1:
The eccentric bushing design is configured to be interchangeable between leading and trailing positions. By properly orienting the bushing during installation, the same bushing component provides the appropriate stiffness or compliance characteristics for either position, eliminating the need for different bushing designs and reducing parts inventory requirements.
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 eccentric bushings improve vehicle stability by constraining roll center displacement and extending effective control arm length, simplifying assembly and maintenance by allowing identical bushings to be used in both positions, and enhancing ride comfort and handling.
Implementation Method 1
an elastomeric material bonded to both the outer sleeve and the inner sleeve assembly, the elastomeric material being at least partly deformable to absorb a torque applied thereto by the outer sleeve
Data Source
AI summary
A suspension system for a vehicle platform comprises a control arm comprising an outboard portion and one or more inboard portions, and one or more eccentric bushings for linking the control arm to a frame of the vehicle platform. Each of the one or more bushings includes an annular outer sleeve seated in an opening of a respective inboard portion of the one or more inboard portions, an inner sleeve assembly nonconcentrically surrounded by the annular outer sleeve, for fixed coupling to the frame of the vehicle platform, and an elastomeric material bonded to both the outer sleeve and the inner sleeve assembly, the elastomeric material being at least partly deformable to absorb a torque applied thereto by the outer sleeve.