Current Sensor Core Positioning via Biasing Member
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Solution Overview
Problem
Current sensors face variations in sensing accuracy due to unstable core positioning and gap distances, caused by factors like uneven resin filling and temperature changes, leading to inconsistent magnetic flux sensing.
Innovation Solution
A current sensor design featuring core members with facing end surfaces and a positioning member that biases and securely positions the core members to maintain a specified gap distance, using inter-gap spacers and guide parts to stabilize the magnetic flux path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the core position is fixed by the mold member filled in the casing, then the core positioning is achieved, but the sensing accuracy varies greatly for each product due to unevenness of filling amount and filling density
Solution Approach 1:
A positioning member is introduced as an intermediary component between the core and the casing. This positioning member includes positioning protrusions that fit into corresponding positioning recesses, providing precise and consistent core positioning independent of mold filling variations. The positioning member acts as a mediator that transfers the positioning function from the mold member to a dedicated component with controlled geometry.
Solution Approach 2:
The positioning function is separated from the mold member by introducing a distinct positioning member component. This segmentation allows the positioning mechanism to be independently designed and manufactured with high precision, while the mold member can be optimized for its original filling function without compromising positioning accuracy.
2Measurement precision
If the core position is fixed by the mold member, then the core is positioned, but the gap distance for Hall element insertion becomes unstable
Solution Approach 1:
The positioning member serves as an intermediary that establishes a stable reference framework for the gap distance. By providing precise positioning of the core relative to the casing through positioning protrusions and recesses, the gap distance for Hall element insertion becomes consistent and reproducible across all products.
3Reliability
If the core members are disposed with gaps between end surfaces, then the magnetic field converging path is formed, but the gap distance varies when positional relationship is displaced
Solution Approach 1:
The positioning member is pre-configured with positioning protrusions and corresponding recesses that establish the correct positional relationship between core members before final assembly. This preliminary positioning action ensures that when the core members are assembled, the gaps between their end surfaces maintain a consistent and controlled distance, forming a reliable magnetic flux path.
Solution Approach 2:
The positioning member acts as an intermediary that controls and maintains the gap distance between core members. The positioning protrusions fit into recesses to constrain the relative positions of core members, ensuring uniform gap distances that are critical for stable magnetic flux convergence and consistent sensing performance.
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 ensures stable and consistent sensing accuracy by maintaining precise gap distances and core positioning, even under varying environmental conditions, improving the reliability of the current sensor.
Implementation Method 1
a plurality of core members which form a converging path of a magnetic field generated by continuity of a current to be sensed
Implementation Method 2
a positioning member which biases the plurality of core members in the facing directions, thereby positioning the plurality of core members in a state of holding the gap distance between the end surfaces facing each other as specified
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A current sensor (100) includes: core members (104a, 104b) which form a converging path of a magnetic field generated by continuity of a current to be sensed by providing gaps (104c) in respective spaces between end surfaces facing each other in a plurality of sections to be disposed in an annular shape; a case body (102) which disposes and houses the core members (104a, 104b) in an annular shape; and a positioning member (108) which positions the core members (104a, 104b) in predetermined positions where the gaps (104c) are held in a specified distance by biasing the core members (104a, 104b) to each other in directions facing each other in the case body (102).