Compact Magnetostrictive Torque Sensor With Nested Coil Assembly
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Solution Overview
Problem
Existing magnetostrictive torque sensors face challenges in securing installation space due to their size, necessitating a reduction in size without compromising functionality.
Innovation Solution
A magnetostrictive torque sensor design comprising a resin holder with a flexible substrate and a magnetic ring, where the flexible substrate is curved between the holder and the magnetic ring, with signal lines led out of the holder, and fixed using a shaft-shaped fastener, allowing for a compact structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the torque sensor uses a resin housing with internal cable connections, then the structural integrity and electrical connectivity are ensured, but the overall size of the sensor becomes too large for narrow installation spaces
Solution Approach 1:
The sensor is divided into modular components: a holder component, a flexible substrate component, and a magnetic ring component. These segments can be independently manufactured and then assembled, allowing for compact integration while maintaining the functional integrity of each part.
Solution Approach 2:
The flexible substrate with signal lines is nested within the holder component, and the magnetic ring is positioned around the holder. This nested arrangement allows multiple functional elements to occupy overlapping spatial volumes, significantly reducing the overall sensor size while maintaining all necessary functions.
2Volume of moving object
If the sensor components are tightly integrated to reduce size, then installation space is saved, but the assembly precision and component alignment become more difficult to achieve
Solution Approach 1:
The holder component is designed with pre-formed through-holes and the magnetic ring is designed with pre-formed retention holes at specific positions. These preliminary structural features serve as alignment guides during assembly, ensuring that components are positioned correctly relative to each other before final tightening, thereby achieving high precision without requiring complex alignment procedures.
Solution Approach 2:
The shaft-shaped fastener acts as an intermediary element that mediates the connection between the holder and magnetic ring. It penetrates through the holder's through-hole and engages with the magnetic ring's retention hole, providing both mechanical fastening and precise positional alignment between the two 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
The design achieves a reduction in sensor size, enabling easy installation in narrow spaces around rotating shafts while maintaining detection accuracy and durability.
Implementation Method 1
magnetostrictive torque sensors are configured to detect torque applied to a rotating shaft based on changes in the inductance of a detection coil placed around the rotating shaft, using the magnetostrictive effect in which the magnetic permeability of the rotating shaft changes due to stress
Data Source
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AI summary
Provided is a magnetostrictive torque sensor that can be reduced in size. A magnetostrictive torque sensor 1 is provided with: a resin holder 2 having a cylindrical part 21 into which a rotating shaft 9 having a magnetostrictive effect is inserted; a flexible substrate 4 that has a detection part 40 having formed in a wiring pattern a coil group obtained by combining a plurality of detection coils arranged in a prescribed direction and that has a signal line part 400 in which a plurality of signal lines 491-494 for electrically connecting the coil group and an external device 8 are formed in the wiring pattern; and a cylindrical magnetic ring 5 made of a soft magnetic material disposed on the outer circumference of the cylindrical part 21 of the holder 2. The detection part 40 is disposed between the cylindrical part 21 of the holder 2 and the magnetic ring 5, and the signal line part 400 is led out to the outside of the holder 2. The holder 2 has an annular wall 23 that surrounds the outer circumference of one axial end part of the magnetic ring 5, and the holder 2 and the magnetic ring 5 are fixed by a shaft-like fastener 6 which is inserted into a fastening hole 510 of the magnetic ring 5 by penetrating through the annular wall 23.