Magnetoelastic Torque Sensor with Segmented Magnetized Sleeve
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing magnetoelastic torque sensors with magnetized sleeves as primary sensors face challenges in achieving high signal quality due to uneven stress distribution and low magnetic flux density, which degrades the sensitivity and signal quality.
Innovation Solution
The magnetized sleeve is constructed in two parts, with a non-magnetic carrier sleeve part and a ferromagnetic material applied via deposition welding, creating a magnetically decoupled system that increases the external magnetic flux density and improves signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a magnetized sleeve is pressed onto the shaft over its entire length, then the sleeve can be securely mounted as a primary sensor, but uneven stress distribution occurs within the sleeve which degrades signal quality
Solution Approach 1:
The magnetized sleeve is divided into two distinct parts: a non-magnetic carrier sleeve part that contacts the shaft, and a ferromagnetic material layer that provides the magnetic flux. This segmentation allows the carrier sleeve to bear the mounting stresses while the ferromagnetic layer remains stress-free, solving the contradiction between secure mounting and signal quality.
Solution Approach 2:
The non-magnetic carrier sleeve acts as an intermediary between the shaft and the ferromagnetic material. It transfers the mounting forces to the shaft without transmitting them to the ferromagnetic layer, thereby protecting the magnetic flux density from degradation while ensuring secure attachment.
2Volume of moving object
If the magnetized sleeve is made small in size, then it fits better on the shaft, but only a rather low magnetic flux density can be generated
Solution Approach 1:
The sleeve uses a composite structure combining non-magnetic carrier material and ferromagnetic material. This composite design allows the ferromagnetic layer to concentrate and enhance the magnetic flux density despite the small overall size of the sleeve, resolving the contradiction between compact dimensions and high magnetic flux density.
3Ease of manufacture
If assembly-related component stresses are present in the magnetized sleeve, then the sleeve can be installed on the shaft, but the signal quality is degraded
Solution Approach 1:
By separating the structural function (carrier sleeve) from the sensing function (ferromagnetic material), the design allows assembly stresses to be confined to the carrier sleeve only. The ferromagnetic material remains stress-free, maintaining high signal quality while enabling easy installation.
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 configuration enhances the sensitivity of the torque sensor by maintaining a high magnetic flux density and improving the magnetic flux distribution, thereby achieving better signal quality with reduced assembly-related stresses.
Implementation Method 1
a ferromagnetic material 2b, in particular iron powder, on an outer lateral surface of the non-magnetic carrier sleeve part 2a by means of deposition welding
Implementation Method 2
increases the external magnetic flux density
Implementation Method 3
changes in the magnetic field can be acquired, which occur under load due to the magnetoelastic effect (inverse magnetostriction) known per se
Implementation Method 4
the sleeve thus magnetized is magnetically decoupled from the shaft
Data Source
AI summary
A torque sensor for measuring a torque on a shaft using the measuring principle of inverse magnetostriction, on which a magnetised sleeve is fastened as the primary sensor. The sleeve is provided with at least two circumferential portions which are arranged at an axial distance from one another and magnetised in opposing directions and interact in a contactless manner with respective measuring coils arranged fixedly opposite hereto for acquiring measured values. The magnetised sleeve consists of a non-magnetic carrier sleeve part, on the outer lateral surface of which the magnetized circumferential portions are attached by deposition welding of a ferromagnetic material.