Clamp Sensor Protruding Cores for Compact Magnetic Coupling

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Solution Overview

Problem

Existing clamp sensors face challenges in maintaining a sufficient magnetic coupling force between core members while being reduced in size, and are prone to gaps or distortions due to external forces or foreign matter, affecting detection accuracy.

Innovation Solution

The clamp sensor design includes protruding portions on both core members that overlap in the closed state, increasing contact area and magnetic coupling force, while also preventing foreign matter interference and accommodating size reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the cross-sectional area of the magnetic core is reduced to enable size reduction of the clamp sensor, then the clamp sensor can be easily used in narrow spaces, but the magnetic coupling force between the first core and the second core becomes insufficient

Engineering Contradiction:
Improvesize of clamp sensorVSAvoidmagnetic coupling force
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

The invention transitions from surface contact to volume contact by providing protruding portions that extend in the circumferential direction. This dimensional change from 2D surface contact to 3D volume contact increases the contact area and magnetic coupling force without increasing the cross-sectional area of the magnetic core, thus resolving the contradiction between size reduction and maintaining magnetic coupling strength.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The protruding portions are provided at specific locations (at least one end portion of both end portions in the circumferential direction) of the first and second cores. This local enhancement of contact area through protruding portions allows the magnetic core to maintain sufficient coupling force at critical interfaces while keeping the overall cross-sectional area reduced for compact size.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If planar end surfaces are used for simple manufacturing, then the manufacturing process is easier, but gaps may occur due to distortion from external forces or foreign matter affecting detection accuracy

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoiddetection accuracy
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The protruding portions are designed in advance to overlap in the circumferential direction when the magnetic core is in the closed state. This beforehand design creates a geometric constraint that prevents gaps from forming due to external forces or foreign matter, ensuring detection accuracy without complicating the manufacturing process.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The protruding portions break the symmetry of the planar end surfaces by extending in the circumferential direction. This asymmetric feature creates an overlapping configuration that inherently prevents gap formation, improving reliability while maintaining manufacturing simplicity through a straightforward geometric modification.

Inventive Principle:
Principle #4Asymmetry

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 ensures reliable clamping and high detection accuracy even in narrow spaces by enhancing magnetic coupling and preventing gaps, despite size reduction and potential distortions.

Implementation Method 1

an annular closed magnetic circuit is formed around the detection target by the first core and the second core, and a magnetic field generated by the current flowing through the detection target can be detected

Methodology Applied
Scientific EffectMagnetic circuit: Magnetism

Implementation Method 2

a magnetic field generated by the current flowing through the detection target can be detected

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 3

increasing contact area and magnetic coupling force

Methodology Applied
Scientific EffectMagnetic coupling: Magnetism

Data Source

PatentEP4582816A1Clamp sensor and measuring device
Publication Date: 2025.07.09 HIOKI DENKI KK
  • EP4582816A1 patent drawingFigure 1
  • EP4582816A1 patent drawingFigure 2
  • EP4582816A1 patent drawingFigure 3

AI summary

The object of the present invention is to cause both core members to adopt a state of being coupled together with a sufficient magnetic coupling force, while achieving a reduction in size. This clamp sensor includes a first core member 21 constituting a part, in a circumferential direction, of a magnetic core 20 that is arranged annularly, and a second core member 22 constituting another part thereof. The clamp sensor is configured such that: first protruding portions that protrude along the circumferential direction are provided at tip ends P21a and P21b in the circumferential direction of the member 21, and second protruding portions that protrude along the circumferential direction are provided at tip ends P22a and P22b in the circumferential direction of the member 22; and in a closed state, the first protruding portions on the tip end P21a side and the second protruding portions on the tip end P22a side overlap in an insertion direction, and the first protruding portions on the tip end P21b side and the second protruding portions on the tip end P22b side overlap in the insertion direction.