Coupled Torsion Beam Axle Suspension Toe-Out Control
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Solution Overview
Problem
Conventional coupled torsion beam axle type suspension systems suffer from instability during vehicle turns and single impact events due to toe-out tendencies of the rear outer wheel, leading to over-steering and deterioration of turning stability, especially when asymmetric thrust and drag forces are applied.
Innovation Solution
The system incorporates a rotation link and slider mechanism that positions the instantaneous rotational center point behind the wheel centers, using a connection link to adjust the rotational center point dynamically, reducing toe-out and enhancing stability by ensuring the outer rear wheel toes-in and the inner rear wheel toes-out during turns, and mitigating toe-out during single impact events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the instantaneous rotational center point is positioned in front of the wheel centers, then the rear outer wheel tends to toe-out during turns, but this causes over-steering and deterioration of turning stability
Solution Approach 1:
The patent inverts the conventional position of the instantaneous rotational center point from in front of the wheel centers to behind the wheel centers. This inversion changes the toe movement characteristics: the rear outer wheel now tends to toe-in and the rear inner wheel tends to toe-out during turns, creating an under-steering tendency that improves turning stability while maintaining the desired toe-out characteristic through the modified geometric configuration
2Reliability
If the instantaneous rotational center point is positioned behind the wheel centers, then the vehicle achieves under-steering and improved turning stability, but the structure becomes more complex
Solution Approach 1:
The patent introduces a rotation link as an intermediary component between the trailing arm and the vehicle body. This rotation link, connected through a slider mechanism, serves as a mediator that dynamically positions the instantaneous rotational center point behind the wheel centers during turns. The intermediary structure enables the desired under-steering behavior and improved turning stability without requiring complete redesign of the entire suspension system
3Reliability
If a rotation link and slider mechanism are added to position the rotational center point behind wheel centers, then turning stability improves, but the device complexity increases
Solution Approach 1:
The rotation link and slider mechanism are designed to perform multiple functions simultaneously: (1) positioning the instantaneous rotational center point behind the wheel centers for under-steering, (2) allowing dynamic adjustment during turns, and (3) maintaining connection between the trailing arm and vehicle body. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving improved turning stability
Data Source
AI summary
A coupled torsion beam axle type suspension system (CTBA) may include trailing arms respectively coupled to opposite ends of a torsion beam, and a vehicle body-engaging unit provided in a front end portion of each of the trailing arm and engaging the each of the trailing arms to a vehicle body, wherein each vehicle body-engaging unit includes a trailing arm bush that may be coupled to a front end portion of the trailing arm, a rotation link disposed in front of the trailing arm bush and engaged thereto in a width direction of a vehicle, a slider rotatably connected to a front end portion of the rotation link, and slidable along a length direction of the vehicle body, and a connection link pivotally connecting an outer end portion of the rotation link and the vehicle body.