Sliding Ride Motion Guide Suspension for Reduced Torque Steer
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Solution Overview
Problem
Conventional MacPherson strut suspension systems face issues with torque steer, brake shudder sensitivity, and limited packaging space, which affect vehicle stability and pedestrian safety, while also requiring significant structural support and space for the shock absorber.
Innovation Solution
A compact vehicle suspension system that separates the functions of the shock absorber and strut, using a sliding ride motion guide with a fixed and telescoping portion, a lower control arm, and an anti-roll bar to manage brake and camber torque, allowing for a more compact design with independent caster angle adjustment and reduced spindle length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional MacPherson strut is used, then structural support and simplicity are provided, but torque steer and brake shudder sensitivity increase due to long spindle length
Solution Approach 1:
The suspension system is divided into separate functional components: a lower control arm for wheel location, a separate strut assembly for shock absorption, and a caster assembly for steering. This segmentation allows each component to be optimized independently, reducing the spindle length and harmful torques while maintaining structural support.
Solution Approach 2:
The shock absorber and spring functions are extracted from the traditional MacPherson strut structure and placed in a separate coil over shock absorber assembly. This extraction allows the steering axis to be repositioned closer to the wheel center, reducing spindle length and torque steer sensitivity.
2Strength
If the top mount is located adjacent to the hood, then structural support is provided, but pedestrian impact protection is reduced due to limited crash crumple zone
Solution Approach 1:
The suspension geometry is redesigned to allow the top mount to be positioned further forward in the vehicle, utilizing the longitudinal dimension rather than being constrained to a lateral position near the hood. This creates additional vertical crumple zone space while maintaining structural support through the separate strut and control arm configuration.
3Strength
If a MacPherson strut requires significant space above the wheel, then structural support is provided, but packaging volume increases
Solution Approach 1:
By separating the control arm and strut assembly into distinct components with independent functions, the overall packaging volume is reduced. The lower control arm handles wheel location while the separate coil over shock absorber handles suspension, eliminating the need for a tall integrated strut structure.
4Strength
If the shock absorber forms part of the structural strut, then structural support is provided, but design flexibility is reduced due to robust rod requirements
Solution Approach 1:
The structural support function is separated from the shock absorption function. The lower control arm and caster assembly provide structural support, while the coil over shock absorber provides damping. This allows the shock absorber to be a lighter, non-structural component with greater design flexibility.
Solution Approach 2:
The shock absorber is extracted from the structural strut role and placed in a separate coil over configuration. This extraction allows independent optimization of the shock absorber design without being constrained by structural support requirements, enabling lighter weight and better packaging.
Data Source
AI summary
A compact vehicle suspension system comprises a sliding ride motion guide having a fixed guide portion and a telescoping guide portion telescopically movable relative to one another. The sliding ride motion guide is fixed to a wheel hub knuckle via the fixed guide portion and is rotatably and structurally fixed via the telescoping guide portion at a top mount to a vehicle body. A coil over shock absorber is rotatably connected to a lower control arm at a first end and to the vehicle body at a second end. Arms of the fixed guide portion of the sliding ride motion guide may span the wheel hub knuckle to which a drive shaft may be connected. Vertical motion of the wheel is defined by a sliding axis of the sliding ride motion guide and an arc of the lower control arm.