U-Shaped Magnetic Shield Fixing for Current Sensor Precision
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Solution Overview
Problem
Existing current sensors with U-shaped magnetic shields face challenges in achieving high positional precision for the magnetic shield relative to the case, while maintaining the external magnetic field attenuation function.
Innovation Solution
The current sensor design incorporates a U-shaped magnetic shield with an attachment portion and a link portion, allowing for precise fixation to a case without compromising the external magnetic field attenuation function. The attachment portion is specialized for fixing to the case, ensuring high precision and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a through-hole is formed in the magnetic shield to fix it to the housing, then the magnetic shield can be fixed to the case, but the external magnetic field attenuation function is compromised
Solution Approach 1:
The magnetic shield is divided into two functional parts: the U-shaped portion that provides magnetic field attenuation and the attachment portion that provides fixing functionality. This segmentation allows each part to optimize its specific function without compromising the other.
Solution Approach 2:
The fixing function is extracted from the U-shaped magnetic shield and transferred to a separate attachment portion. This extraction allows the U-shaped portion to maintain its integrity for magnetic field attenuation while the attachment portion handles the fixing requirement.
2Reliability
If the magnetic shield is fixed using a resin portion with claws, then the magnetic shield can be fixed to the substrate, but positional deviation may occur between the magnetic shield and the resin portion
Solution Approach 1:
The attachment portion is integrally formed with the U-shaped magnetic shield as a single piece, eliminating the need for separate resin portions and claws. This merging ensures precise positional relationship while maintaining fixing reliability through the link portion's engagement with the case.
Solution Approach 2:
The link portion acts as an intermediary element that connects the U-shaped magnetic shield to the attachment portion. It provides a precise mechanical interface that ensures accurate positioning while allowing the attachment portion to be securely fixed to the case.
3Object-affected harmful factors
If the magnetic shield has a three-dimensional U-shaped structure, then it can provide effective magnetic field attenuation, but it becomes difficult to fix with high positional precision
Solution Approach 1:
The magnetic shield structure is segmented into the U-shaped portion for magnetic field attenuation and the flat attachment portion for precise fixing. This segmentation allows the three-dimensional U-shaped structure to maintain its magnetic shielding effectiveness while the flat attachment portion provides a stable base for precise positional fixation to the case.
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 design enhances measurement precision for the magnetic sensor by maintaining the external magnetic field attenuation function while allowing for precise positioning of the U-shaped magnetic shield, thereby improving the overall performance of the current sensor.
Implementation Method 1
a magnetic shield having a portion that faces the bus bar along a third direction... U-shaped magnetic shield... external magnetic field attenuation function
Data Source
AI summary
A current sensor has: a bus bar extending in a first direction; a magnetic shield having a portion that faces the bus bar along a third direction; a magnetic sensor facing the bus bar along the third direction on an opposite side of the bus bar to a side on which the magnetic shield is placed; and a case molded integrally with part of the bus bar. The magnetic shield has: a U-shaped portion that has a bottom wall including a portion that faces the bus bar along the third direction and also has two side walls, facing each other in the second direction, that is erected in the third direction from ends of the bottom wall in a second direction; an attachment portion that is adjoined to the U-shaped portion and is fixed to the case; and a link portion that links the U-shaped portion and attachment portion together.