Magnetic Switch Non-Magnetic Protector for Iron Sand Interference
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Solution Overview
Problem
Magnetic type switches used to detect brake pedal operations can be affected by external factors like iron sand, which interfere with the magnetic field, leading to inaccurate detection.
Innovation Solution
A magnetic type switch design where the magnetic pole face of the magnet is positioned to face a stay with a protector member that covers the area of high magnetic flux density, preventing iron sand from being magnetized and accumulating, thus maintaining the integrity of the magnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnet is provided to detect brake pedal operation, then detection function is improved, but iron sand accumulates on the magnet surface causing detection errors
Solution Approach 1:
A non-magnetic protective layer is introduced as an intermediary between the magnet and the external environment. This layer prevents iron sand from directly contacting and accumulating on the magnet surface while allowing the magnetic field to pass through for detection purposes.
Solution Approach 2:
A thin protective coating is applied to the magnet surface. This film acts as a barrier against iron sand accumulation while maintaining the magnetic field's ability to detect brake pedal position accurately.
2Measurement precision
If the magnet is exposed to detect changes in magnetic field, then detection sensitivity is improved, but the magnetic field becomes vulnerable to external interference
Solution Approach 1:
The protective coating is applied selectively to the magnet surface where iron sand accumulation is most likely to occur. This localized protection maintains magnetic field sensitivity in detection areas while preventing interference from external magnetic materials.
Solution Approach 2:
The non-magnetic protective layer serves as a mediator that shields the magnet from external magnetic materials like iron sand, preventing them from distorting the magnetic field while allowing the field to remain sensitive to brake pedal position changes.
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 magnetic field is protected from external magnetic materials, ensuring accurate detection of brake pedal operations without interference, improving detection accuracy and preventing the accumulation of iron sand.
Implementation Method 1
magnetic force lines extend in the vertical direction to the magnetic pole face
Implementation Method 2
the iron sand pulled in by the magnetic force of the magnet cannot be closer to the magnet than the protector member, and the pulled-in iron sand cannot be magnetized
Data Source
Figure 1A~1C
Figure 2A~2C
Figure 3A~3B
AI summary
[Problem] Magnetic field by a magnet in a switch is not subjected to an influence of iron sand or the like. [Solution to Problem] There is provided a magnetic type switch 1 in which a magnetic pole face 71a of a magnet 71 is arranged to face a stay 23 provided in a brake pedal 2, and a change in magnetic field due to a change in distance between the stay 23 and the magnet 71 by an operation of the brake pedal 2 is detected to output a signal for indicating presence/absence of the operation of the brake pedal 2. The magnetic pole face 71a of the magnet 71 faces the stay 23 to have a bottom wall part 53 therebetween in an accommodation part 51 of a body casing 5 having the bottom wall part 53 as a facing part to the stay 23, and the protector member 9 made of a non-magnetic material having a predetermined thickness in a direction vertical to the magnetic pole face 71a is attached to the accommodation part 51 to cover at least the bottom wall part 53 with the protector member 9.