Current Sensor Guide Plate Assembly Accuracy

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Solution Overview

Problem

Current sensors face challenges in achieving high detection accuracy due to assembly errors and thermal expansion differences between the circuit board and housing, leading to increased assembly complexity and reduced accuracy.

Innovation Solution

A current sensor design featuring a plate-like member with guide holes of reduced diameter to facilitate accurate assembly of connection terminals, along with an engaging portion and engaged portion positioned centrally to minimize thermal deformation effects, and a manufacturing method that includes bending connection terminals to absorb displacement and ensure secure soldering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the gap between the core and element main body is expanded to facilitate assembly, then assembly ease is improved, but detection accuracy deteriorates

Engineering Contradiction:
Improveassembly easeVSAvoiddetection accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

A guide plate is introduced as an intermediary component between the element main body and the circuit board. The guide plate provides guide holes that constrain the insertion path of connection terminals, ensuring accurate positioning during assembly while maintaining a small gap for high detection accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The guide holes are preliminarily formed in the guide plate with precise dimensions and positions. This preliminary action establishes the correct spatial relationship between components before assembly, enabling accurate insertion of connection terminals without requiring large adjustment gaps.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If the assembling accuracy of element main body to core is set roughly to facilitate assembly, then assembly ease is improved, but detection accuracy deteriorates due to thermal expansion differences

Engineering Contradiction:
Improveassembly easeVSAvoiddetection accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The guide holes are designed with specific dimensional parameters (diameter, position, orientation) that accommodate thermal expansion while maintaining positioning accuracy. The parameters are optimized to allow for coefficient of thermal expansion differences between the circuit board and housing while preventing excessive movement that would reduce detection accuracy.

Inventive Principle:
Principle #35Parameter changes

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 enhances assembly accuracy and detection precision while simplifying the assembly process, maintaining high accuracy over time by reducing thermal-induced shifts and improving soldering reliability.

Implementation Method 1

guide holes in which the connection terminals are inserted and which have a diameter reduced from the side of the housing toward the side of the circuit board

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the plural connection terminals are fixed to the circuit board by soldering or the like

Methodology Applied
Scientific EffectSoldering: Soldering

Data Source

PatentEP2746782B1Current sensor and manufacturing method for the same
Publication Date: 2016.10.12 AISIN SEIKI KK
  • EP2746782B1 patent drawingFigure 1~2
  • EP2746782B1 patent drawingFigure 3
  • EP2746782B1 patent drawingFigure 4

AI summary

A current sensor (A) includes: a housing (6) that holds a busbar (1) to which a current is applied and a core (2) arranged around the busbar; a circuit board (4) fixed to the housing in the state of being arranged to face the housing; and a detection element (3) for detecting the current; wherein the detection element has an element main body (3a) held in the housing and plural connection terminals (3b) fixed in through-holes (4a) in the circuit board, and a plate-like member (5) provided with guide holes (5a) in which the connection terminals are inserted and which have a diameter reduced from the side of the housing toward the side of the circuit board is provided on a surface facing the housing, of two surfaces of the circuit board.