Sensor Unit Shielding Casing Earthing for Arc Prevention
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Solution Overview
Problem
Sensor units for sensing the angular position of a rotatable element often experience harmful electric potential differences between the shielding casing and the printed circuit board due to magnetic fields, leading to potential damage from electric arcs.
Innovation Solution
The method involves earthing the shielding casing by electrically connecting it to a load discharging device on the printed circuit board, using protruding elements or contact pads to establish a stable electrical connection, preventing uncontrolled electric potential increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a shielding casing is used to protect the printed circuit board from intense magnetic fields, then the protection against magnetic fields is improved, but electric potential differences occur between the shielding casing and the printed circuit board leading to harmful electric arcs
Solution Approach 1:
The patent applies the equipotentiality principle by electrically connecting the shielding casing to the printed circuit board through a conductive bridge, ensuring both components are at the same electric potential. This eliminates the harmful electric potential differences and prevents electric arcs while maintaining the magnetic field protection function of the shielding casing.
Solution Approach 2:
The patent introduces an intermediary conductive bridge that mediates between the shielding casing and the printed circuit board. This intermediary element provides a controlled electrical connection path that equalizes potential without compromising the shielding effectiveness against magnetic fields, thus resolving the contradiction between protection and harmful electric potential generation.
2Object-affected harmful factors
If the shielding casing is made of metallic material to block magnetic fields, then the magnetic field shielding effectiveness is improved, but electric arcs can occur and destroy electronic components on the printed circuit board
Solution Approach 1:
By establishing an electrical connection between the metallic shielding casing and the printed circuit board, the patent ensures equipotential conditions are maintained. This prevents the accumulation of electric potential that would otherwise lead to arcs and component destruction, thereby preserving electronic component reliability while maintaining magnetic field shielding effectiveness.
Solution Approach 2:
The patent applies preliminary anti-action by proactively providing an electrical discharge path before harmful electric arcs can form. The conductive bridge预先 establishes a safe potential equalization mechanism that prevents the development of dangerous potential differences, thereby protecting electronic components before failure can occur.
3Object-generated harmful factors
If the shielding casing is electrically isolated from the printed circuit board, then electric arcs are prevented, but uncontrolled increases in electric potential can occur and damage electronic components
Solution Approach 1:
The patent resolves this contradiction by implementing equipotentiality through a conductive connection between the shielding casing and the printed circuit board. This ensures that both components remain at the same electric potential, preventing both electric arcs and uncontrolled potential increases, thereby maintaining electronic component reliability.
Solution Approach 2:
The conductive bridge acts as an intermediary that provides a controlled electrical connection, mediating between the shielding casing and the printed circuit board. This intermediary ensures safe potential equalization while preventing the harmful effects of both electric arcs and uncontrolled potential buildup, thus protecting electronic components.
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 solution effectively prevents damage to electronic components on the printed circuit board by maintaining a stable electric potential in the shielding casing, thereby safeguarding the sensor unit from electric arcs.
Implementation Method 1
an encoder element fast with the rotatable element, adapted to generate magnetic field variations as a function of its angular position
Implementation Method 2
a sensing element fast with the fixed element, adapted to sense the magnetic field variations
Implementation Method 3
earthing the shielding casing by electrically connecting it to a load discharging device of the printed circuit board
Data Source
AI summary
A method of producing a sensor unit for sensing the angular position of a rotatable element with respect to a fixed element, providing an encoder element fastened to the rotatable element, adapted to generate magnetic field variations as a function of its angular position, and a sensing element fastened to the fixed element, adapted to sense the magnetic field variations. The sensing element is mounted on and connected to a printed circuit board mounted in a shielding casing fastened with the fixed element. The method further comprises a step consisting in earthing the shielding casing by electrically connecting it to a load discharging device of the printed circuit board.