Zero Caster Wheel Steering Device for Stability
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Solution Overview
Problem
Existing wheel steering devices are susceptible to changes in steering angle due to forces from uneven road surfaces, leading to inefficiencies and energy consumption, particularly when dealing with single-wheel independent steering systems.
Innovation Solution
A wheel steering device with a steering knuckle and actuator that maintains a caster angle and caster offset of 0, allowing for reduced pivoting action and independent steering of individual wheels, incorporating an electric motor and controller for energy-efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional suspension geometry with non-zero caster angle and caster offset is used, then the steering device can provide self-aligning torque and stability, but the steering angle changes significantly when forces act on the wheel from uneven road surfaces
Solution Approach 1:
The patent changes the geometric parameters of the suspension system by setting the caster angle and caster offset to substantially 0. This parameter change fundamentally alters how the steering knuckle responds to vertical forces from the road surface, eliminating the traditional self-aligning torque mechanism that caused steering angle variations. The steering angle stability is improved by removing the geometric configuration that made the system sensitive to road surface forces.
2Object-affected harmful factors
If caster angle and caster offset are set to 0, then the steering knuckle becomes less susceptible to pivoting forces from road surface unevenness, but the self-aligning torque and traditional steering stability are reduced
Solution Approach 1:
The patent replaces the traditional mechanical self-aligning torque mechanism (which relies on non-zero caster geometry) with an alternative steering stability approach. By setting caster parameters to 0, the system eliminates the mechanical self-centering effect, and steering stability must be achieved through other means such as active control or different kinematic configurations.
3Ease of operation
If traditional suspension geometry is used, then the steering device responds naturally to road conditions, but energy is consumed to counteract unwanted steering angle changes
Solution Approach 1:
By changing the caster angle and caster offset parameters to substantially 0, the patent modifies the steering system's response characteristics to road inputs. This reduces the energy-consuming pivoting actions that occur with traditional geometry, as the steering knuckle becomes less sensitive to vertical road forces while maintaining operational responsiveness.
Data Source
AI summary
A wheel steering device for a vehicle, including: a steering knuckle that constitutes a part of a suspension device and that is capable of moving relative to a body of the vehicle in an up-down direction, the steering knuckle holding a wheel such that the wheel is rotatable; and a steering actuator configured to cause the steering knuckle to be pivoted about a kingpin axis so steer the wheel, wherein a caster angle and a caster offset are both 0.