Microminiature Displacement Sensor Lateral Force Resistance
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Solution Overview
Problem
Existing displacement sensors are limited by their bulk size, which hinders further miniaturization while maintaining mechanical integrity and accurate measurement, especially in applications requiring small sizes and resistance to lateral forces.
Innovation Solution
The design incorporates a pair of spaced bearings with an outer diameter matching the housing's inner diameter to resist lateral forces and jewel bearings for free axial movement, along with a return spring and air actuation to improve accuracy and bypass obstacles, allowing for substantial size reduction while maintaining measurement precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the displacement sensor is miniaturized, then the size is reduced, but the resistance to lateral forces deteriorates
Solution Approach 1:
The sensor is divided into functional segments: a housing containing the coil, a separate core assembly with bearings, and a guidance mechanism. This segmentation allows each component to be optimized independently - the core can be made extremely small while the housing provides structural support and lateral force resistance through its larger bearing surfaces.
Solution Approach 2:
Jewel bearings are introduced as intermediary elements between the core and housing. These bearings mediate the interaction between the moving core and stationary housing, enabling free axial movement of the miniaturized core while the housing's larger bearing surfaces resist lateral forces. The bearings transfer axial loads efficiently while isolating the core from lateral force exposure.
2Volume of moving object
If the core is made smaller for miniaturization, then the sensor size is reduced, but the mechanical integrity deteriorates
Solution Approach 1:
The mechanical support system is replaced with jewel bearings that provide low-friction, high-precision support. Instead of relying on the core's own structural integrity to resist all forces, the jewel bearings provide a dedicated mechanical support system that handles axial loads and lateral forces separately, allowing the core to be miniaturized without compromising reliability.
Solution Approach 2:
The core assembly uses composite construction with the core made from high-strength, low-density materials optimized for axial movement, while the housing and bearings provide complementary mechanical properties for lateral force resistance. This composite approach allows each material to be optimized for its specific function rather than requiring the core material to handle all mechanical demands.
3Volume of moving object
If the sensor is made smaller, then the size is reduced, but the resistance to lateral rotation deteriorates
Solution Approach 1:
The guidance mechanism uses spaced bearings arranged in a dimensional configuration that provides rotational stability. By positioning bearings at different axial locations and orientations, the system resists lateral rotation through three-dimensional geometric constraints rather than relying solely on the core's own dimensional stability, enabling miniaturization while maintaining rotational resistance.
4Strength
If the bearing outer diameter is increased to resist lateral forces, then the lateral force resistance is improved, but the sensor size increases
Solution Approach 1:
The housing and bearing support functions are merged into a single integrated component. The housing serves dual purposes: containing the coil and providing the bearing surfaces for lateral force resistance. This eliminates the need for separate, larger bearing components, allowing lateral force resistance to be achieved within the compact housing dimensions rather than requiring additional size increases.
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 approach enables the creation of microminiature displacement sensors with reduced size, improved resistance to lateral forces, and enhanced measurement accuracy, suitable for applications like biomedical implants and production lines.
Implementation Method 1
The displacement sensor includes a coil and a captive core. An electrical measurement of the coil provides information about displacement of the core.
Data Source
AI summary
A device for providing displacement information includes a housing holding a displacement sensor. The displacement sensor includes a coil and a captive core. An electrical measurement of the coil provides information about displacement of the core. The coil has an axis extending in a first direction, wherein the housing has a minimum outside dimension that is less than 3.00 mm when measured perpendicular to that first direction. The housing has an inner surface having a housing inside dimension. The housing is for holding a displacement sensor and a guidance mechanism. The displacement sensor includes a coil and a captive core having a core outside dimension. The guidance mechanism includes a first part and a second part for guiding the core. The first part includes a bearing connected to the housing. The bearing has an axial hole having a hole dimension about equal to the core outside dimension. The core slidably extends through this axial hole. The second part has a second part outside dimension about equal to the housing inside dimension. The guidance mechanism is for resisting lateral movement and lateral rotation of the core while allowing axial movement of the core into and out of the coil.