Reciprocating Electromagnetic Resistance Device with Back-EMF Sensing
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Solution Overview
Problem
Conventional strength training equipment lacks precise control and data quantification, and active driving systems with motors pose safety concerns due to reliance on multiple sensors.
Innovation Solution
A reciprocating unidirectional electromagnetic resistance device integrating an electromagnetic braking unit and a spring return device, utilizing a one-way clutch and serrated toroidal core with coils, and sensing devices for precise control and reduced sensor dependence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If motor-based active driving systems are used to achieve precise control and data quantification, then measurement precision and control accuracy are improved, but device complexity and safety risks increase due to reliance on multiple sensors
Solution Approach 1:
The patent extracts the sensing function from the driving system by using a passive electromagnetic resistance device that generates its own back-EMF signal. The flywheel with electromagnetic braking unit produces electrical signals directly during operation, eliminating the need for separate sensors to detect motion parameters. This resolves the contradiction by achieving data quantification without adding sensor complexity.
Solution Approach 2:
The electromagnetic resistance device serves itself by generating measurable electrical signals (back-EMF) during its normal operation. The flywheel's rotation through the magnetic field automatically produces voltage signals that can be measured and quantified, making the system self-monitoring without requiring external sensing components. This eliminates safety risks associated with multiple sensors while maintaining measurement precision.
2Measurement precision
If motor-based active driving systems are used to achieve precise control, then measurement precision is improved, but reliability decreases due to safety concerns when sensors malfunction
Solution Approach 1:
The patent removes vulnerable sensors from the system and extracts the measurement function into the passive electromagnetic device itself. The back-EMF signals generated by the flywheel provide inherent feedback about its operational state without requiring external sensing components that could malfunction. This improves reliability by eliminating sensor failure risks while maintaining control precision through the electromagnetic feedback mechanism.
Solution Approach 2:
The system monitors its own state through self-generated electrical signals during operation. The electromagnetic braking unit continuously produces measurable back-EMF voltages that reflect the flywheel's speed and operational conditions, providing inherent safety monitoring without external sensors. This self-service approach ensures reliable operation even when external sensing systems would fail.
3Reliability
If conventional magnetoresistive systems are used to ensure safety and stability, then reliability is improved, but the ability to achieve reciprocating motion and precise control deteriorates
Solution Approach 1:
The patent introduces a one-way clutch mechanism that enables dynamic reciprocating motion while maintaining the passive safety characteristics of conventional magnetoresistive systems. The clutch allows the flywheel to rotate freely in one direction (absorbing energy) while preventing reverse rotation, creating automatic reciprocating motion. This resolves the contradiction by enabling operational versatility without compromising the inherent safety and stability of passive electromagnetic resistance.
Solution Approach 2:
The system segments the motion control function by separating the resistance generation (passive electromagnetic braking) from the motion direction control (one-way clutch). The electromagnetic unit provides stable, safe resistance force while the clutch mechanism independently manages the reciprocating motion pattern. This functional segmentation allows both reliability and ease of operation to coexist without interference.
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 solution provides high-accuracy, safe, and data-quantified resistance with reduced sensor dependence, enabling precise control and dynamic balance, addressing the safety and quantification issues of conventional systems.
Implementation Method 1
an electromagnetic braking unit, having a toroidal core, a plurality of serrated portions formed at an outer ring of the toroidal core, and a plurality of coils wound around the serrated portions respectively; the electromagnetic braking unit being installed between the hub and the outer ring body of the flywheel
Implementation Method 2
the serrated portion being configured to be facing an inner ring surface of the outer ring body to produce an electromagnetic resistance
Implementation Method 3
a spring return device, coupled to the shaft or the winding wheel, for driving the winding wheel to rewind the pulled-out pull rope
Implementation Method 4
a one-way clutch, with an inner ring surface sheathed on a first end of the shaft, and the hub being sheathed and coupled to an outer ring surface of the one-way clutch
Data Source
AI summary
A reciprocating unidirectional electromagnetic resistance device includes a shaft having a flywheel installed to a first end of the shaft, an electromagnetic braking unit, and a first sensing device. A spring return device and a second sensing device are installed at a second end of the shaft, and a pull rope device is installed at the middle of the shaft. The electromagnetic braking unit and the spring return device are integrated into a single module and provided for an operator to perform a reciprocating motion to pull out a pull rope of the pull rope device and drive the shaft, the flywheel and the spring return device synchronously, and the electromagnetic braking unit acts an electromagnetic resistance onto the flywheel, so that the flywheel has the excellent precise resistance of the electromagnetic braking unit. When released, the pull rope can be retracted to achieve the reciprocating motion effect.