Two-Wheeled Vehicle Steering Shaft Link for Low-Speed Stability
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Solution Overview
Problem
Riders of motorcycles with steering ratio varying systems need to adapt handlebar manipulation to changing steering characteristics at low speeds to maintain balance, which can be challenging and unstable.
Innovation Solution
A mobile vehicle with a steering section that includes a first and second steering axis, a posture detector, and a control section that adjusts the steering shaft link and front-wheel support section to apply restoring force, allowing self-sustaining control to stabilize the vehicle at low speeds and normal traveling speeds, enabling the vehicle to maintain stability without rider adaptation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the steering ratio is changed by the steering ratio varying means responsive to the traveling speed, then the steering angle of the front wheel with respect to the handlebar manipulated variable decreases as the vehicle speed increases, but the rider needs to manipulate the handlebar by adapting to the change characteristics of the steering ratio, which makes it difficult to secure stability during stopping or low-speed traveling
Solution Approach 1:
The system uses the second motor to automatically adjust the steering shaft link position based on detected vehicle speed, without requiring rider input. The control section monitors speed and autonomously repositions the steering shaft link to maintain optimal steering characteristics across different speed ranges, allowing the system to serve itself rather than requiring continuous rider adaptation.
Solution Approach 2:
The invention dynamically changes the steering shaft link position parameter in response to vehicle speed changes. At low speeds, the link is positioned to provide larger steering angles for balance control, while at higher speeds, the link position adjusts to reduce steering angle for stability. This parameter adjustment resolves the contradiction by automatically adapting steering characteristics to speed conditions without rider intervention.
2Adaptability or versatility
If the steering ratio is changed by the steering ratio varying means responsive to the traveling speed, then the steering characteristics are optimized for different speeds, but the rider needs to adapt to the change characteristics, which increases the difficulty of maintaining balance at low speeds
Solution Approach 1:
The second motor and control section form an autonomous system that self-adjusts the steering shaft link position based on vehicle speed detection. This eliminates the need for rider adaptation to steering ratio changes, as the system automatically maintains optimal steering characteristics for the current speed condition, thereby preserving posture stability while providing adaptability.
Solution Approach 2:
The steering shaft link acts as an intermediary element between the handlebar and the front wheel. By repositioning this intermediary component based on speed conditions, the system modifies the steering transmission characteristics without requiring the rider to directly adapt their handlebar manipulation, thus maintaining reliability while providing versatility.
3Device complexity
If a single steering axis is used, then the structure is simple, but the vehicle cannot maintain both stability during stopping/low-speed traveling and good straight traveling at higher speeds
Solution Approach 1:
The invention introduces a movable steering shaft link that can dynamically reposition itself along the steering axis based on vehicle speed. This dynamic adjustment capability allows the single steering axis structure to provide different steering characteristics at different speeds, achieving both low-speed stability and high-speed straight traveling without requiring a complex multi-axis structure.
Solution Approach 2:
The steering axis function is segmented into two distinct functions performed by the same physical structure: the first steering axis for handlebar input and the second steering axis (through the movable link) for front wheel control. This segmentation allows independent optimization of steering characteristics for different speed ranges while maintaining a relatively simple overall structure.
Data Source
AI summary
A two-wheeled vehicle 1 includes a steering section 6 which steers a front wheel 4. The steering section includes a steering shaft link 13 which turns about a first steering axis 10 together with a second steering axis 11, a front-wheel support section 14 which turns the front wheel 4 about the second steering axis 11, and a first motor 15 which causes the steering shaft link 13 to turn. A caster angle θ based on the first steering axis 10 is positive or 0. A trail t1 based on the second steering axis 11 is positive. When the two-wheeled vehicle 1 is in a basic posture state on a ground surface 12, the intersection point P3 of the second steering axis 11 and the ground surface 12 lies in front of the intersection point P2 of the first steering axis 10 and the ground surface 12.