Asymmetrical Ball Joint for Variable Ground Clearance Suspension
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Solution Overview
Problem
Existing motor vehicle rear axle suspension systems cannot be used on vehicles with different ground clearances without costly modifications, as the caster angle is affected by the change in ground clearance, leading to undesirable steering behavior.
Innovation Solution
A wheel suspension assembly with an asymmetrical lower ball joint that can be mounted in two distinct directions, allowing for angular offset of the steering pivot axes to compensate for changes in ground clearance, enabling the same suspension train to be used on vehicles with varying ground clearances while maintaining similar caster angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the same rear axle is used on vehicles with different ground clearances, then manufacturing cost is reduced, but the caster angle changes leading to undesirable steering behavior
Solution Approach 1:
The lower ball joint is designed with asymmetry, having two distinct mounting directions that create different steering pivot axes with angular offset. This allows the same suspension train to provide identical or close caster angles on vehicles with different ground clearances by selecting the appropriate mounting direction, thus resolving the contradiction between manufacturing economy and steering performance reliability
Solution Approach 2:
The asymmetrical lower ball joint provides multi-functionality by enabling the same suspension train to be adapted to vehicles with different ground clearances through two distinct mounting directions. This universal design allows a single suspension assembly to serve multiple vehicle types without modification, maintaining both manufacturing efficiency and steering behavior reliability
2Length of moving object
If the axle-to-chassis articulation points are raised for high ground clearance vehicles, then ground clearance requirement is met, but the caster angle is modified which is undesirable
Solution Approach 1:
The asymmetrical lower ball joint compensates for the geometric changes caused by raised articulation points on high ground clearance vehicles. By providing two distinct mounting directions with angular offset, it allows selection of the mounting orientation that maintains the desired caster angle, thus preserving manufacturing precision for caster angle while accommodating different ground clearance requirements
3Reliability
If costly modifications are made to the axle for different vehicle types, then steering behavior is optimized, but manufacturing cost increases
Solution Approach 1:
The asymmetrical lower ball joint creates a universal suspension train design that can be used across different vehicle types without costly modifications. By incorporating two distinct mounting directions in a single component, it eliminates the need for separate suspension designs for different ground clearance vehicles, thus optimizing steering behavior while reducing manufacturing costs
Data Source
Figure 1A
Figure 1B
Figure 2A~3
AI summary
The invention relates to an assembly which comprises, at each end of an axle crosspiece, a longitudinal arm for connecting to a chassis of the vehicle, and a stub axle (1) mounted on the arm via two connecting ball joints (4, 5), top and bottom, which define a steering pivot axis. One of the two ball joints (5), top and bottom, is asymmetrical and mountable in two different directions such as to define two separate steering pivot axes, angularly offset.