Vehicle Suspension Lower Arm Toe-In Prevention
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Solution Overview
Problem
Conventional independent front suspensions in vehicles tend to cause a toe-in state of the wheels during braking, leading to oversteer and compromised steering stability, with attempts to adjust bushing rigidity either worsening riding comfort or reducing steering stability.
Innovation Solution
The independent suspension design features a lower arm with pivot shafts having central axes that are inclined in a toe-in direction and a front connection point offset from the rear pivot shaft, allowing for controlled displacement to prevent toe-in and enhance steering stability without compromising comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rigidity of the rear bushing is increased to reduce inward displacement of rear connection point, then steering stability is improved, but vibration transmission to vehicle body increases, worsening riding comfort
Solution Approach 1:
The patent changes the geometric parameters of the lower arm by inclining the central axes of front and rear pivot shafts in the toe-in direction and offsetting the front connection point position. This geometric modification alters the force distribution and displacement characteristics during braking, preventing wheel toe-in without requiring changes to bushing rigidity, thereby avoiding vibration transmission issues.
2Reliability
If the rigidity of the front bushing is reduced to increase outward displacement of front connection point, then steering stability is improved, but the rigidity of lower link in width direction decreases, worsening steering stability
Solution Approach 1:
The patent modifies the geometric parameters of the lower arm by inclining the pivot shaft axes and offsetting connection point positions. This approach achieves the desired outward displacement effect without reducing bushing rigidity or compromising the structural strength and rigidity of the lower link in the width direction.
3Ease of manufacture
If conventional double wishbone suspension geometry is used with standard bushing rigidity, then manufacturing is simplified, but wheel toe-in occurs during braking, worsening steering stability
Solution Approach 1:
The patent changes the geometric parameters of the lower arm (pivot shaft axis inclination and connection point offset) to prevent wheel toe-in during braking. This maintains standard bushing rigidity and conventional suspension assembly methods, preserving ease of manufacture while improving steering stability.
Data Source
AI summary
An independent suspension for a vehicle, including upper and lower arms pivotally moveable in a vertical direction of the vehicle, an axle with a wheel center which is connected with the upper and lower arms, and a tie rod connected with the axle at a connection point rearward of the wheel center in a fore-and-aft direction of the vehicle. The lower arm is connected to the vehicle body at front and rear connection points spaced from each other in the fore-and-aft direction of the vehicle through front and rear pivot shafts with bushings. The central axis of the front pivot shaft is inclined relative to the central axis of the rear pivot shaft in a toe-in direction of the wheel.