Measurement Device Rotation Detection Through Sealed Casing
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Solution Overview
Problem
Conventional measurement devices face challenges in maintaining adequate waterproof and dustproof properties due to the formation of holes for setting changing mechanisms, which can lead to failures in harsh environments.
Innovation Solution
A measurement device design featuring a concave portion in the casing for a rotatable shaft, with a magnet and magnetic sensors aligned to detect rotation without penetrating holes, ensuring waterproof and dustproof properties through a gasket and lid configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a hole is formed in the casing to allow a shaft to penetrate for setting changes, then the ease of operation is improved, but the waterproof and dustproof properties deteriorate
Solution Approach 1:
The patent replaces the mechanical rotary encoder system with a magnetic field-based detection system. A magnet is attached to the shaft, and magnetic sensors mounted on the circuit board detect the magnet's position and rotation without requiring the shaft to penetrate the casing, thus maintaining waterproof and dustproof properties while enabling setting changes
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the shaft and the detection system. The magnet on the shaft creates a magnetic field that can be detected by magnetic sensors through the casing wall, allowing information transfer without physical penetration or direct contact
2Reliability
If a gasket is used to seal the shaft in the hole, then the waterproof properties are partially improved, but the reliability remains inadequate in harsh environments
Solution Approach 1:
The patent extracts the shaft from the casing interior by having it pass through a non-penetrating concave portion rather than forming a through-hole. The shaft remains outside the sealed casing, eliminating the need for seals and gaskets that could fail, while the magnetic coupling allows rotation detection without physical connection
Solution Approach 2:
The patent uses the casing wall itself as a barrier, with magnetic sensors mounted on the inner surface detecting the magnet through the casing material. This approach treats the casing as a non-penetrating barrier that maintains sealing while allowing magnetic field transmission
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 design provides reliable waterproof, dustproof, and explosion-proof properties while enabling seamless setting changes, simplifying assembly, and allowing for downsized and flexible component arrangement within the casing.
Implementation Method 1
a magnetic sensor (9) that detects a position and an intensity of a magnetic field generated by the magnet (6)
Data Source
AI summary
A measurement device includes a casing in which a storage space is formed thereinside; a board that has a mounting surface, and that is housed in the storage space; a magnetic sensor mounted on the mounting surface; and a detecting unit that is arranged outside the casing, and that detects a state quantity of a measured medium. A protruding portion that is formed by protruding an inner circumferential surface of the storage space is formed in the casing. A concave portion formed by recessing toward the storage space from an outer circumferential surface of the casing is formed in the protruding portion. The board is arranged such that the mounting surface faces the protruding portion.