Rotation Angle Sensor Magnet Fixing Mechanism
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Solution Overview
Problem
Conventional rotation angle detecting apparatuses for accelerator pedals face issues with magnet fixation due to external shocks, misalignment, and durability problems, particularly when using resin caulking or spring-based fixation methods.
Innovation Solution
A rotation angle detecting apparatus with a fixing member that presses a magnet against an abutting part using a biasing force generated by rotating between the magnet and an inclined supporting part, preventing the magnet from loosening and allowing easy replacement, and incorporating a rotation preventing part to maintain stable fixation under external shocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat-softened resin is used to caulk-fix the magnet, then the magnet is prevented from falling off, but the heat and pressure cause misalignment and loosening of the magnet
Solution Approach 1:
The patent replaces the thermal-mechanical caulking process with a pure mechanical fixation system. The fixing member uses elastic deformation (bending) to generate pressing force against the magnet, eliminating the need for heat and pressure application. This mechanical approach maintains magnet alignment precision while achieving reliable fixation through the elastic restoring force of the bent fixing member.
Solution Approach 2:
The fixing member acts as an intermediary between the rotating member and the magnet. By bending the fixing member, elastic potential energy is stored, which then serves as a mediator to continuously apply pressing force to the magnet without requiring direct thermal or mechanical intervention during operation. This intermediary mechanism ensures stable magnet positioning.
2Reliability
If strong pressure and high heat are applied to adhere resin to the magnet, then the magnet is fixed, but the holding force and durability of the magnet deteriorate
Solution Approach 1:
The patent substitutes the thermal-mechanical adhesion process with a pure mechanical pressing system. The fixing member, when bent, generates elastic restoring force that continuously presses the magnet against the rotating member. This eliminates exposure to high heat and pressure, preserving the magnet's inherent holding force and durability while achieving reliable fixation through mechanical means.
3Device complexity
If the magnet is press-fitted and fixed without additional fixation methods, then the structure is simple, but the magnet loosens under external shock
Solution Approach 1:
The patent segments the fixation function into two independent components: the press-fit initial positioning and the fixing member for continuous pressing. This segmentation allows the simple press-fit structure to remain while adding a dedicated elastic fixing member that compensates for loosening under external shock, maintaining both structural simplicity and fixation reliability.
Solution Approach 2:
The bent fixing member provides beforehand cushioning by pre-storing elastic potential energy that is released as continuous pressing force. This anticipates and counteracts the loosening effect of external shocks before they can cause magnet displacement, ensuring reliable fixation without complex additional structures.
4Reliability
If a plate spring is used to fix the magnet, then the magnet can be fixed, but the accuracy of attaching the spring becomes unstable
Solution Approach 1:
Instead of embedding the fixing member in a frame (as with plate springs), the patent inverts the approach by having the fixing member directly engage the magnet and press it against the rotating member. The fixing member is supported by the rotating member itself rather than an external frame, reversing the support relationship and eliminating the need for precise embedding operations.
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 stable and durable magnet fixation without the need for high-pressure or high-temperature methods, ensuring accurate rotation angle detection even under strong external shocks, and allows for easy replacement of the fixing member.
Implementation Method 1
a magnet to generate a magnetic field on the accelerator pedal side, and a sensor to detect a behavior of the magnetic field
Implementation Method 2
The sensor converts the density of a magnetic flux, the angle of which changes as the magnet rotates
Data Source
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AI summary
An object of the present invention is to fix a magnet of a rotation angle sensor easily and steadily without using a heat caulking method and the like. To achieve the object, provided is a rotation angle sensor for detecting a rotation angle of a rotating member in which, when fixing a magnet to the rotating member, the magnet can be fixed easily by employing a fixing member that generates a biasing force by rotating in a gap between the magnet and the rotating member. Furthermore, provided is a rotation angle sensor in which a magnet can be prevented from loosening by external shock and variation of the detection angle of the magnet can be suppressed by providing a rotation preventing part for preventing a fixing member from loosening due to its inverse rotation.