Steerable Wheel Chassis for Electric Mobility
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Solution Overview
Problem
Existing electrically driven wheelchair chassis face challenges in achieving a balance between long driving distance, maneuverability, low weight, minimal size, low complexity, and the ability to overcome obstacles, with previous solutions often resulting in energy inefficiency, large turning radii, and difficulties with sloping surfaces.
Innovation Solution
A chassis design featuring a rigid frame with a pair of parallel side wheels, a steerable front wheel, and a steerable rear wheel connected through a turning mechanism that allows synchronous movement between parallel and perpendicular positions, optimizing energy efficiency and simplifying steering, while allowing for tiltable side wheels to enhance obstacle climbing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If two parallel non-steerable wheels are used for propulsion, then the structure is simple, but the turning radius is large and energy efficiency is poor
Solution Approach 1:
The patent combines the steering and propulsion functions into a single wheel assembly. Each wheel is steerable and driven, merging what were previously separate functions into one integrated component. This eliminates the need for separate steering mechanisms while maintaining propulsion capability, thereby reducing overall system complexity and improving energy efficiency by allowing direct force application in the direction of motion.
Solution Approach 2:
Each wheel in the patent serves multiple functions: it provides propulsion through its driven mechanism and steering through its ability to rotate about a vertical axis. This multi-functionality eliminates the need for dedicated steering components, reducing system complexity while improving energy efficiency by allowing the wheel to directly control both motion and direction.
2Device complexity
If two parallel non-steerable wheels are positioned at the rear, then the structure is simple, but the ability to drive down sloping surfaces is poor
Solution Approach 1:
The patent makes the wheel assembly dynamic by allowing each wheel to independently steer and adjust its orientation. This dynamic capability enables the vehicle to adapt to sloping surfaces by adjusting wheel angles, improving downslope driving capability while maintaining structural simplicity through the absence of complex suspension or adjustment mechanisms.
3Ease of operation
If a steerable front wheel with mechanical coupling to handlebars is used, then steering control is precise, but the turning radius is large
Solution Approach 1:
Instead of using a traditional front-wheel steering configuration where the front wheel steers and the rear wheel follows, the patent inverts the approach by making both front and rear wheels steerable and independently controllable. This allows for more flexible turning patterns including perpendicular wheel positions, enabling tight turning radii while maintaining precise steering control through electronic or mechanical coupling systems.
4Ease of operation
If rotary shaft above driving wheel is added for steering, then steering capability is improved, but installation height increases and wheel size decreases
Solution Approach 1:
The patent extracts the steering function from a separate rotary shaft mechanism and integrates it directly into the wheel assembly itself. Each wheel can rotate about its own vertical axis to achieve steering, eliminating the need for an external rotary shaft above the wheel. This reduces installation height and allows for larger wheel sizes while maintaining full steering capability.
Data Source
AI summary
The present invention relates to a chassis for vehicle, comprising: a rigid frame, a pair of side wheels in a parallel configuration, a steerable front wheel, a steerable rear wheel, at least one electric motor, wherein at least one of said front wheel or rear wheel is connected to and driven by the at least one electric motor, and wherein said front and rear wheels are mutually connected through a turning mechanism arranged to turn said front and rear wheels simultaneously and synchronously between a middle position in which the axles of the front and rear wheels are substantially parallel with the axles of side wheels, and left or right positions, in which the axles of the front and rear wheels are substantially perpendicular to the axles of the side wheels.