Semi-Trailing Suspension Toe-Out Control
Solution Overview
Problem
The existing semi-trailing suspension devices experience instability and toe-out issues when a braking force is applied, leading to discomfort and reduced vehicle stability due to the alignment of the turning axis and suspension movable axis.
Innovation Solution
The semi-trailing suspension device features a trailing bush with a turning axis inclined toward the vehicle body's inner rear side, a hinge mechanism allowing relative displacement between the trailing and lower arms, and a damper and spring arrangement where the damper is closer to the inner side of the lower arm, enhancing stability and comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the turning axis of the trailing bush is aligned with the suspension movable axis, then the suspension device has a simple structure, but vehicle stability deteriorates when braking force is applied due to toe-out displacement
Solution Approach 1:
The turning axis of the trailing bush is intentionally misaligned with the suspension movable axis, creating an asymmetric geometric relationship. This asymmetric configuration ensures that when braking force is applied, the resulting moment directs the wheel toward a toe-in position rather than toe-out, thereby maintaining vehicle stability while preserving structural simplicity
2Ease of manufacture
If the turning axis of the trailing bush intersects the imaginary line connecting axle center to trailing arm turning center at an angle greater than 90 degrees, then the suspension device follows conventional design, but wheel toe-out occurs during braking reducing comfort
Solution Approach 1:
The invention changes the critical geometric parameter - the intersection angle between the trailing bush turning axis and the imaginary line connecting the axle center to the trailing arm turning center. By adjusting this angle to be less than or equal to 90 degrees, the patent modifies the force transmission characteristics during braking, directing the wheel to a toe-in position that enhances ride comfort while maintaining manufacturability
3Area of stationary object
If the damper is positioned farther from the vehicle width direction inner side, then more space is available for other components, but damper movement increases during braking reducing ride comfort
Solution Approach 1:
The damper is pre-positioned closer to the vehicle width direction inner side of the lower arm, anticipating the braking condition. This preliminary positioning ensures that during braking, the damper experiences minimal movement, thereby maintaining ride comfort. The space trade-off is accepted as a necessary compromise to achieve the desired comfort performance
Data Source
AI summary
Provided is a semi-trailing suspension device including: a trailing arm that is coupled to a vehicle body in a turnable manner; a trailing bush that is provided between the vehicle body and the trailing arm and pivotally supports the trailing arm in a turnable manner; a lower arm that is coupled to the vehicle body in a turnable manner; a lower arm bush that is provided between the vehicle body and the lower arm and pivotally supports the lower arm in a turnable manner; and a hinge mechanism that couples the trailing arm and the lower arm to each other in a relatively displaceable manner.