Vehicle Suspension Knuckle Layout to Reduce Torque Steer
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Solution Overview
Problem
In vehicles equipped with in-wheel motors, the increased kingpin offset leads to torque steer phenomena, where the wheel is arbitrarily steered due to applied driving and braking power, narrowing the wheel space and affecting stability.
Innovation Solution
A suspension apparatus with a separated steering axis and suspension axis configuration, utilizing a rotation restriction member between the second knuckle and shock absorber to prevent integral rotation of the second knuckle with the first knuckle, supported by a pair of suspension arms and a leaf spring, which reduces the kingpin offset and enhances stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the kingpin offset is increased to enable in-wheel motor installation, then the driving power can be applied directly to the wheel, but torque steer phenomenon occurs and wheel space is narrowed
Solution Approach 1:
The invention separates the steering axis and suspension axis into different knuckles (first knuckle for steering, second knuckle for suspension), dividing the previously integrated functions. This segmentation allows independent optimization of steering and suspension functions, eliminating torque steer while maintaining in-wheel motor benefits
Solution Approach 2:
The rotation restriction member acts as an intermediary between the first and second knuckles, preventing unwanted rotational coupling. This intermediary component ensures that steering inputs are not contaminated by suspension movements, eliminating torque steer phenomenon
2Power
If the kingpin offset is increased, then in-wheel motor can be installed, but wheel space is narrowed
Solution Approach 1:
By separating steering and suspension functions into different knuckles, the invention optimizes the spatial arrangement of wheel components. This allows better utilization of wheel space while maintaining the in-wheel motor configuration
3Device complexity
If the second knuckle is allowed to rotate with the first knuckle, then the suspension structure is simpler, but the wheel is arbitrarily steered during bumping and rebound
Solution Approach 1:
The rotation restriction member serves as an intermediary that selectively restricts rotation. It prevents the second knuckle from rotating during suspension movement while allowing controlled steering rotation, eliminating arbitrary wheel steering without overly complicating the suspension structure
Solution Approach 2:
The invention changes the rotational parameters of the knuckles by introducing the rotation restriction member. This modifies the degrees of freedom of the second knuckle, allowing it to move vertically while preventing unwanted rotational movement that would cause arbitrary steering
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces the kingpin offset, improves driving and braking stability, prevents excessive movement of the second knuckle during bumping and rebound, and eliminates the need for additional links, thereby reducing vehicle weight and cost.
Implementation Method 1
an elastic body disposed between the outer pipe and the inner pipe
Implementation Method 2
a leaf spring may disposed to face the second knuckle and elastically deformed in conjunction with a movement of the second knuckle
Data Source
AI summary
The suspension apparatus may include a driving unit configured to provide driving power to a wheel, a first knuckle coupled with the driving unit, rotated around a steering axis, and configured to change a steering angle of the wheel, a second knuckle disposed to face the first knuckle and configured to rotatably support the first knuckle, a suspension arm configured to extend from a vehicle body and to support the second knuckle against the vehicle body, a shock absorber connected to the second knuckle and configured to absorb a shock that is applied to the second knuckle, and a rotation restriction member provided between the second knuckle and the shock absorber and configured to restrict the second knuckle from being rotated along with the first knuckle.