Inductive Angular Displacement Sensor for Rolling Bearings
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Solution Overview
Problem
Existing inductive displacement sensors, particularly angular displacement sensors, face limitations in precision, robustness, and linearity, being sensitive to mounting inaccuracies and conductive parts, with fragile designs that are not suitable for industrial environments, and have limited measurement ranges and linearity issues.
Innovation Solution
The development of an inductive angular displacement sensor with a robustly attached target to a bearing ring, featuring a transducer with primary and secondary windings and a conductive target with specific pattern distributions, optimized target-transducer distance, and additional electromagnetic field confinement parts to enhance linearity and robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic encoder is used to measure rotational speed, then the bearing can provide speed measurement for anti-lock braking systems, but the encoder-sensor assembly has very limited precision and cannot measure absolute angular position
Solution Approach 1:
The patent replaces the magnetic encoder-sensor assembly with an inductive sensor system that uses electromagnetic induction principles. The inductive sensor comprises a transducer with primary and secondary windings that generate and detect electromagnetic fields, eliminating the need for magnetic poles and sensors. This substitution improves measurement precision while reducing device complexity by using a more straightforward electromagnetic induction mechanism.
Solution Approach 2:
The patent changes the measurement principle from magnetic field detection to inductive electromagnetic field detection. By using a transducer with primary and secondary windings that operate on electromagnetic induction, the system achieves higher precision in angular displacement measurement. The target is designed with specific geometric parameters (annular band, radial position) that optimize the inductive coupling and enhance measurement accuracy.
2Reliability
If the target is firmly attached to the bearing ring, then the sensor robustness improves, but the attachment process becomes more complex
Solution Approach 1:
The patent merges the target with the bearing ring by directly machining the target from the bearing ring material itself. This integration eliminates the need for separate attachment processes such as pressing or welding. The target becomes an intrinsic part of the bearing ring, achieving maximum robustness and reliability while simplifying manufacturing by reducing the number of assembly steps and potential failure points from detached components.
3Manufacturing precision
If additional electromagnetic field confinement parts are added, then linearity and robustness improve, but device complexity increases
Solution Approach 1:
The patent introduces electromagnetic field confinement parts as intermediary elements between the transducer and the target. These confinement parts serve as mediators that shape and control the electromagnetic field distribution, ensuring uniform field lines and improving measurement linearity. By acting as field guides, these intermediate structures enhance measurement precision without requiring complex adjustments to the primary sensor or target design.
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 solution improves the precision, robustness, and linearity of angular displacement measurements, reducing sensitivity to inaccuracies and environmental factors, and extends the measurement range, making the sensor more suitable for industrial applications.
Implementation Method 1
a transducer comprising at least one primary winding adapted to produce a magnetic excitation, and at least one secondary winding comprising at least one turn, adapted to supply an electromotive force across its terminals in the presence of said excitation
Implementation Method 2
said target being formed from a single conductive metal piece and comprising a face with a bottom wall and one or more metal studs projecting from this bottom wall
Data Source
Figure 1A~4
Figure 5~8
Figure 9A~12D
AI summary
The invention relates to a bearing (500) comprising a bearing race and an inductive sensor for detecting the angular movement of said bearing race, which comprises a transducer and a target (511). The target is made of a single conductive metal part and comprises a surface with a back wall (509) and one or more metal contacts (507i) projecting from said bottom wall. The target (511) is sturdily attached to the bearing race, or is directly machined into the bearing race.