Lever Member Stress Distribution in Position Detection
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Solution Overview
Problem
In existing position detection devices, stress concentration occurs at the peripheral portion of the lever element due to forces applied along the central axis of rotation, leading to potential deformation and failure.
Innovation Solution
A position detection device design featuring a lever member with a thick plate portion near the central axis and a thinner thin plate portion farther away, along with a tapered portion connecting them, to distribute stress and prevent concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the lever element is formed in a flat plate shape extending from its central axis of rotation, then the structure is simple and easy to manufacture, but stress concentration occurs at the peripheral portion of the central axis of rotation when force is applied along the central axis of rotation
Solution Approach 1:
The lever element employs varying thickness across different regions: a thick plate portion at the central axis of rotation to resist stress concentration, and a thin plate portion at the peripheral end for lightweight operation. This local variation in geometric properties optimizes both structural strength and manufacturing simplicity.
Solution Approach 2:
The thickness parameter of the lever element is changed along its length, transitioning from a thick plate portion near the central axis to a thin plate portion at the peripheral end. This parameter gradient resolves the contradiction by providing adequate strength where needed while maintaining overall simplicity.
2Ease of manufacture
If the lever element is made with uniform thickness throughout, then manufacturing is simplified, but stress concentration occurs at the central axis when force is applied at the end portion
Solution Approach 1:
Different regions of the lever element have different thicknesses: the thick plate portion at the central axis provides stress resistance for reliable operation, while the thin plate portion at the end reduces overall mass. This local differentiation maintains reliability without excessive manufacturing complexity.
Solution Approach 2:
The lever element is segmented into distinct thick and thin plate portions along its length, with each segment optimized for its specific functional requirements. The thick portion handles stress concentration at the axis, while the thin portion provides lightweight actuation at the end.
3Strength
If a thick plate portion is provided at the central axis of rotation, then stress concentration is suppressed, but the device weight increases
Solution Approach 1:
The thick plate portion is localized only at the central axis of rotation where stress concentration occurs, rather than making the entire lever element thick. This localized reinforcement provides necessary strength while minimizing additional weight.
Solution Approach 2:
The lever element is divided into thick and thin plate portions, concentrating the mass only where structurally necessary at the central axis, while the majority of the lever (thin plate portion) remains lightweight for efficient motion.
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
This configuration effectively suppresses stress concentration and deformation, allowing for reliable operation even under applied forces, while also reducing the device's weight and facilitating easier manufacturing.
Implementation Method 1
a magnet element rotates relative to a sensor element in association with rotation of a lever element. Accordingly, the rotation of the lever element is detected by the sensor element.
Data Source
AI summary
Provided is a position detecting device with which it is possible to suppress a concentration of stress. A position detecting device is provided with a lever member which rotates about a central axis of rotation O, a magnet unit, which is one example of a detected portion, that rotates about the central axis of rotation O as the lever member rotates and a magnetic detecting element, which is one example of a rotation detecting unit, that detects the rotation of the magnet unit. The lever member is provided with a thick plate portion, positioned in a location close to the central axis of rotation O, and a thin plate portion which is positioned farther from the central axis of rotation O than the thick plate portion, and which is formed thinner than the thick plate portion.