McPherson Suspension Actuator Decoupling Steering Rotation
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Solution Overview
Problem
In McPherson front axles, the simultaneous turning of the shock absorber and helical compression spring during wheel deflection causes unintentional vertical adjustments due to the axial offset of the spring and shock absorber axes, leading to deformation and loss of precision in steering motions.
Innovation Solution
Integration of an electromotive actuator with an axial anti-friction bearing and a spindle driven by an electric motor, decoupling the helical compression spring from the adjusting nut during steering motions, and using a ball screw mechanism or inertia drive to maintain precision vertical adjustment without transverse forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the shock absorber and helical compression spring turn simultaneously during wheel deflection, then the steering motion is achieved, but unintentional vertical adjustments occur due to the axial offset of the spring and shock absorber axes
Solution Approach 1:
The system is divided into two independent rotational segments: the shock absorber assembly that turns with the wheel carrier during steering, and the adjusting nut that remains stationary relative to the spindle axis. The axial anti-friction bearing enables this segmentation by allowing the spring to rotate independently without driving the adjusting nut, thus preventing unintentional vertical adjustments while maintaining steering functionality
Solution Approach 2:
The axial anti-friction bearing acts as an intermediary element between the rotating helical compression spring and the adjusting nut. It allows the spring to rotate freely during steering motions without transmitting rotational force to the adjusting nut, thereby decoupling the steering rotation from the vertical adjustment mechanism and eliminating the harmful coupling effect
2Adaptability or versatility
If an electromotive actuator with adjusting nut directly on the spring plate is used, then vertical adjustment is enabled, but the adjusting nut turns unintentionally during steering causing loss of precision
Solution Approach 1:
The system separates the vertical adjustment function from the steering rotation function by positioning the adjusting nut on the spindle axis rather than directly on the spring plate. The axial anti-friction bearing creates a segmentation where the spring rotates independently during steering while the adjusting nut remains stationary, preserving adjustment precision
Solution Approach 2:
The axial anti-friction bearing serves as an intermediary that allows the spring to rotate without driving the adjusting nut. This intermediary element enables the electromotive actuator to provide precise vertical adjustment while preventing the adjusting nut from turning unintentionally during steering motions
3Force
If the axial offset of the helical compression spring to the center axis of the shock absorber is used to equalize transverse forces, then transverse force equalization is achieved, but transverse forces cause deformation of the actuator and ball screw mechanism
Solution Approach 1:
The harmful effect of transverse forces on the actuator mechanism is extracted and eliminated by aligning the spindle axis with the shock absorber center axis. This positioning removes the actuator from the path of transverse forces generated by the axial offset, allowing the spring to equalize transverse forces without transmitting them to the actuator components
Solution Approach 2:
The axial anti-friction bearing acts as an intermediary that allows the spring to handle transverse force equalization through its axial offset without transmitting these forces to the adjusting nut and actuator mechanism. The bearing isolates the actuator from transverse loads, preserving structural integrity
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
The solution ensures precise vertical adjustment without unintentional changes in vehicle height, maintains equalization of transverse forces, and prevents deformation of the actuator and ball screw mechanism, ensuring free tire movement and universal resilience during steering.
Implementation Method 1
with the interposition of an axial anti-friction bearing on the upper spring plate
Implementation Method 2
the base part being supported on the body by way of a rubber-elastic shock absorber bearing
Implementation Method 3
an electromotive actuator with an inertia drive or ball screw mechanism
Data Source
AI summary
The invention relates to a wheel suspension for steered wheels of motor vehicles having a telescoping shock absorber which is preferably permanently connected to the wheel carrier and a helical compression spring which surrounds it and which is clamped between a lower spring plate which is preferably permanently connected to the shock absorber tube and an upper, body-side spring plate. According to the invention for vertical adjustment of the body around the shock absorber there is an actuator, and the actuator acts by way of an actuating pinion with the interposition of an axial anti-friction bearing on the upper spring plate.