Wheelchair Wheel Resolver Assembly for Precise Rim Handle Sensing
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Solution Overview
Problem
Existing wheel assemblies for wheelchairs are expensive due to the use of a rotational displacement detection mechanism involving a permanent magnet and Hall element, and require complex wiring and brush contacts.
Innovation Solution
A resolver assembly comprising three printed circuit boards is used to detect rotational displacement of the rim handle relative to the wheel, eliminating the need for permanent magnets and Hall elements, and allowing for easy disassembly and external power supply, reducing manufacturing costs and improving accuracy and response time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an annular permanent magnet and Hall element are used for rotational displacement detection, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent extracts and eliminates the expensive permanent magnet and Hall element from the detection system, replacing them with a cost-effective alternative that maintains measurement precision through a different technical approach
Solution Approach 2:
The patent employs cheaper alternative components (such as using the hub motor's existing magnets and a simplified detection mechanism) to replace the expensive permanent magnet and Hall element assembly, reducing manufacturing costs while maintaining functional requirements
2Measurement precision
If an annular permanent magnet and Hall element are used for rotational displacement detection, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the detection function with existing components in the hub motor assembly, eliminating the need for separate permanent magnet and Hall element installations, and reducing wiring complexity by utilizing integrated circuits and existing electrical connections
Solution Approach 2:
The patent makes the hub motor's permanent magnets serve dual purposes: both for motor operation and for rotational position detection, eliminating the need for separate detection components and reducing overall system complexity
3Reliability
If the power source and controller are integrated in the wheel assembly, then reliability is improved, but ease of repair worsens
Solution Approach 1:
The patent segments the wheel assembly from the power source and controller, allowing the wheel assembly to be easily removed and replaced as a modular unit while maintaining system reliability through proper connection interfaces
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 resolver assembly provides accurate and quick monitoring of rim handle displacement, enabling precise power assist functions while being cost-effective and easy to manufacture, with interchangeable components.
Implementation Method 1
a resolver assembly (21) comprising: a wheel resolver (22) which is configured to generate a wheel resolver signal (S1); a rim handle resolver (24) which is configured to generate a rim handle resolver signal (S2)
Data Source
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AI summary
Wheel assembly, in particular for a wheel chair comprising. The wheel assembly includes a wheel shaft extending along a shaft axis and which is configured to be non-rotatably connectable to a frame of the wheelchair. A wheel with a wheel hub is mounted on the wheel shaft so as to be rotatable around the shaft axis. The wheel assembly is provided with a hub motor having a power input and with a rim handle connected to the wheel and being rotatable relative to the wheel over an angle. A resolver assembly of the wheel assembly comprises a wheel resolver which is configured to generate a wheel resolver signal, a rim handle resolver which is configured to generate a rim handle resolver signal, and at least one resolver assembly output for outputting the wheel resolver signal and the rim handle resolver signal.