Swing Arm Layout With Virtual Kingpin Axis for Hub Motor Steering
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Solution Overview
Problem
The integration of hub motors in electric vehicles increases kingpin offset, leading to higher steering resistance torque, larger turning radius, and changes in four-wheel alignment parameters, which negatively affect vehicle dynamics and tire wear.
Innovation Solution
A layout structure of swing arm assembly that includes a rim, hub motor, steering knuckle, and swing arm components, where the hub motor is mounted in the rim, and the swing arm components form a virtual kingpin axis with an inclined top end towards the vehicle interior, reducing kingpin offset and steering resistance torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a hub motor is mounted in the rim, then the power system is integrated and space is saved, but the kingpin offset increases
Solution Approach 1:
The suspension system is divided into two independent swing arm components: an upper swing arm connected to the steering knuckle and a lower swing arm connected to the hub motor stator. This segmentation allows each component to be optimized independently, enabling the lower swing arm to form a virtual kingpin axis that reduces kingpin offset while maintaining the integrated hub motor structure.
Solution Approach 2:
A virtual kingpin axis is introduced as an intermediary concept between the hub motor and the steering system. The virtual kingpin axis is formed by the connection line between the first hinge point (lower swing arm-hub motor connection) and the second hinge point (upper swing arm-steering knuckle connection), serving as a mediator that reduces kingpin offset without requiring physical modification to the hub motor itself.
2Device complexity
If kingpin offset is increased to accommodate hub motor, then the power system integrates, but steering resistance torque increases
Solution Approach 1:
The virtual kingpin axis acts as an intermediary that decouples the hub motor integration from the steering resistance torque issue. By positioning the virtual kingpin axis such that its intersection with the ground is close to the tire grounding center, the system achieves power integration while maintaining low steering resistance torque through the geometric relationship established by the two swing arms.
Solution Approach 2:
The invention changes the geometric parameters of the suspension system by introducing a virtual kingpin axis with specific orientation (top end inclined towards vehicle interior) and positioning (intersection close to grounding center). These parameter changes enable the system to simultaneously achieve hub motor integration and minimize steering resistance torque.
3Device complexity
If kingpin offset is increased, then the hub motor fits, but turning radius becomes larger
Solution Approach 1:
The virtual kingpin axis serves as a geometric intermediary that allows the hub motor to be integrated in the rim while maintaining a compact turning radius. The specific configuration of the virtual kingpin axis (formed by the two swing arms) creates favorable kinematic characteristics that reduce the turning radius compared to traditional suspension designs with hub motors.
4Device complexity
If kingpin offset is increased, then the hub motor integrates, but four-wheel alignment parameters change
Solution Approach 1:
Dividing the suspension into upper and lower swing arms allows independent optimization of alignment characteristics. The lower swing arm's universal connection to the hub motor stator and the upper swing arm's universal connection to the steering knuckle create a virtual kingpin axis that maintains stable four-wheel alignment parameters during vehicle operation.
Solution Approach 2:
The invention optimizes specific geometric parameters of the swing arm assembly, including the inclination of the virtual kingpin axis (top end towards vehicle interior) and the positioning of its ground intersection (close to tire grounding center). These parameter optimizations ensure stable four-wheel alignment parameters while accommodating the hub motor.
Data Source
AI summary
A layout structure of swing arm assembly is disclosed, including a rim, a hub motor, a steering knuckle, and a swing arm component, wherein a tire is mounted at the rim, the hub motor is located in the rim, the rim is connected to a rotor of the hub motor; the steering knuckle is fixedly connected to a stator of the hub motor; the swing arm component comprises an upper swing arm and a lower swing arm; the lower swing arm is universally connected with the stator of the hub motor to form a first hinge point, the upper swing arm is universally connected with the steering knuckle to form a second hinge point, a connection line between the first hinge point and the second hinge point constitutes a virtual kingpin axis, and a top end of the virtual kingpin axis is inclined towards the inside of the vehicle.