Magnetic Resistance Pedal Exerciser Eddy Current Drag
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Solution Overview
Problem
Existing pedal exercisers provide poor exercise effect due to dynamic friction force that decreases as pedaling speed increases, making the exercise feel effortless at high speeds.
Innovation Solution
A pedal exerciser incorporating a support unit, a rotary unit with a worm wheel and worm shaft, and a magnetic resistance unit that includes a rotary disc assembly, magnetic assembly, and adjustment assembly to provide a drag force that increases with pedaling speed, using magnets to generate a rotation-resisting force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a friction-based resistance adjuster is used to provide rotation-resisting force, then the device structure is simple, but the resistance becomes dynamic friction force at high speeds which decreases exercise effectiveness
Solution Approach 1:
The patent replaces the friction-based mechanical resistance system with a magnetic resistance system. The magnetic resistance unit includes magnets that generate magnetic fields interacting with a conductive member (such as a copper or aluminum disc) to produce electromagnetic drag force. This substitution eliminates the problem of dynamic friction at high speeds while maintaining a relatively simple device structure.
Solution Approach 2:
The patent changes the physical parameter of resistance generation from friction force to electromagnetic drag force. The magnetic resistance increases with rotational speed due to the nature of eddy current damping, ensuring consistent exercise effectiveness across different pedaling speeds. The resistance magnitude can be adjusted by changing the distance between the magnetic assembly and the conductive member.
2Device complexity
If friction force is used as rotation-resisting force, then the resistance mechanism is simple, but heat generation occurs and exercise effect decreases at high speeds
Solution Approach 1:
The patent substitutes the friction-based mechanical resistance system with a magnetic resistance system using electromagnetic induction. The magnetic resistance unit employs magnets positioned near a conductive member that rotates with the crank. As the conductive member moves through the magnetic field, eddy currents are induced, creating a drag force that provides rotation resistance without physical contact, thereby eliminating heat generation from friction.
3Ease of operation
If a friction-based resistance system is used, then adjustment is simple, but the resistance decreases at high pedaling speeds making exercise effortless
Solution Approach 1:
The patent changes the resistance mechanism from friction-based to electromagnetic-based. The magnetic resistance force naturally increases with rotational speed due to the velocity-dependent nature of eddy current damping. This ensures that the resistance remains effective at high pedaling speeds, preventing the exercise from becoming effortless while maintaining ease of adjustment through the magnetic assembly positioning mechanism.
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 pedal exerciser offers an efficient exercise effect by increasing resistance with pedaling speed, eliminating heat generation issues from friction, and ensuring operational smoothness by preventing dust and debris entry.
Implementation Method 1
The at least one magnet is capable of producing a drag force as the rotation-resisting force when the conductive member is rotated to move past the at least one magnet
Implementation Method 2
The magnetic resistance unit provides a rotation-resisting force to resist an exercising force applied to the pedals
Data Source
AI summary
A pedal exerciser includes a worm shaft meshed with a worm wheel. A crank drives rotation of the worm wheel through two pedals. A rotary disc assembly is journaled to and rotatable with the worm shaft. The rotary disc assembly has a conductive member that is non-magnetizable and that is rotatable around an axis of the worm shaft. A magnetic assembly is disposed near the conductive member and has a magnet facing the conductive member. The magnet produces a drag force to resist an exercising force when the conductive member is rotated to move past the magnet. An adjustment assembly moves the magnetic assembly toward or away from the rotary disc assembly to vary the magnitude of the drag force.