Multi-Link Suspension Geometry for Zero Bump Steer
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Solution Overview
Problem
Existing multi-link suspension systems for vehicles fail to achieve zero bump steer, non-changing initial castor, and constant scrub radius, especially in high-travel applications, leading to undesirable steering feedback and track width changes during suspension travel.
Innovation Solution
A multi-link suspension system with a fifth aligning link that utilizes a three-position graphical synthesis in two-dimensional and three-dimensional designs to maintain a constant trail and scrub radius, minimizing bump steer and allowing independent movement of links to optimize camber and castor, while keeping track width constant during suspension travel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional multi-link suspension systems are used, then suspension travel is achieved, but bump steer occurs and track width changes during suspension travel
Solution Approach 1:
The suspension system divides the control of wheel movement into independent segments: the multi-link suspension mechanism handles vertical travel while the separate steering linkage maintains horizontal position. This segmentation allows each subsystem to optimize its function without interfering with the other, preventing bump steer while maintaining full suspension travel capability
Solution Approach 2:
A constant track width linkage acts as an intermediary mechanism between the suspension links and the steering system. This intermediate component ensures that as the suspension links move vertically to provide travel, the constant track width linkage compensates to maintain consistent horizontal wheel positioning, thereby eliminating track width changes and bump steer
2Length of moving object
If conventional multi-link suspension systems are used, then suspension travel is achieved, but steering feedback from external forces increases
Solution Approach 1:
The invention extracts and separates the steering function from the suspension travel function. By using a dedicated constant track width linkage independent of the steering mechanism, external forces affecting suspension travel are prevented from being transmitted to the steering system, thereby eliminating unwanted steering feedback while preserving full suspension travel
Solution Approach 2:
The constant track width linkage serves as an intermediary that isolates the steering system from external forces. This intermediate mechanism absorbs and manages forces from suspension travel, preventing them from reaching the steering linkage and causing feedback to the driver
3Device complexity
If suspension links are constrained to move together, then structural simplicity is maintained, but camber and castor optimization is limited
Solution Approach 1:
The suspension system segments the movement of links into independent articulations. Each link can move independently to achieve optimal camber and castor angles while maintaining overall structural simplicity. This independent movement capability allows precise control of wheel geometry without requiring complex constrained mechanisms
Data Source
AI summary
Methods for configuring a suspension system for a vehicle are disclosed such that the suspension system has zero scrub radius and zero bump steer. The method details the specific steps required to achieve these goals.