Disturbing Magnetic Field Generator Vibration Isolation
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Solution Overview
Problem
Existing disturbing magnetic field generators in card readers generate noise due to core vibration, which is transmitted through the card insertion part, causing discomfort to users despite sealing measures.
Innovation Solution
Incorporating a first gap between the tubular body part and the core, and using soft adhesives to bond them, limiting coupling points between the bobbin and circuit board, and providing gaps between the coil and circuit board, along with a third gap between the case and the case housing part to suppress vibration transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the core and bobbin are rigidly coupled to transmit magnetic field efficiently, then the magnetic field generation is improved, but vibration from the core is transmitted to the bobbin and case, causing noise
Solution Approach 1:
The patent introduces a vibration isolation structure as an intermediary element between the core and the bobbin case. This intermediary component absorbs and dampens mechanical vibrations from the core while allowing the magnetic field to pass through, thus resolving the contradiction between efficient magnetic field transmission and noise reduction
Solution Approach 2:
The patent changes the physical parameters of the coupling between core and bobbin by introducing compliant or damping materials. This modifies the mechanical coupling characteristics to reduce vibration transmission while maintaining sufficient magnetic coupling for effective disturbing magnetic field generation
2Reliability
If a large AC signal is supplied to generate a strong disturbing magnetic field, then the anti-skimming effectiveness is improved, but the core vibration increases, causing larger noise
Solution Approach 1:
The vibration isolation structure acts as a mediator that allows the system to operate at high power levels for effective anti-skimming while preventing the associated vibrations from reaching the case and generating noise, thus resolving the contradiction between reliability and noise generation
Solution Approach 2:
The patent extracts the vibration generation function from the noise transmission path by isolating the vibrating core from the case structure. This allows the core to vibrate freely to generate strong magnetic fields while the noise is prevented from propagating to the exterior
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
Effectively reduces noise generation by preventing vibration transmission from the core to the bobbin, circuit board, and case, enhancing user comfort and reducing noise levels.
Implementation Method 1
a coil (12) to generate a disturbing magnetic field
Implementation Method 2
the tubular body part and the core are bonded by a soft adhesive provided in the first gap
Data Source
AI summary
Provided are a disturbing magnetic field generator and a card reader capable of suppressing the generation of noise caused by vibration of a core. A disturbing magnetic field generator that generates a disturbing magnetic field for disturbing unauthorized reading of magnetic data recorded on a card includes a coil to generate the disturbing magnetic field, a bobbin including a tubular body part in which the coil is wound on an outer peripheral side, and a core disposed inside the tubular body part. A first gap is provided between the tubular body part and the core.