Solenoid Shading Ring Annular Contact Noise Reduction
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Solution Overview
Problem
Solenoids energized by Alternating Current (AC) produce objectionable noise due to magnetic force variations, which can lead to instability and premature failure, and existing noise reduction techniques like shading rings are ineffective in the presence of misalignment or debris, increasing production costs.
Innovation Solution
A solenoid design with a core and plunger having junction surfaces with a shallow concave cone and perimeter relief, respectively, to concentrate magnetic attraction within an annular contact region, enhancing stability and reducing noise by improving magnetic force distribution and resistance to return spring force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shading ring is used to reduce noise, then magnetic force stability is improved, but the solution becomes ineffective when gaps or misalignment occur between core and plunger
Solution Approach 1:
The invention applies different surface geometries to different regions of the core and plunger junction surfaces. The core has a shallow concave cone at its center while the plunger has a perimeter relief, creating an annular contact region. This local differentiation ensures that magnetic attraction is concentrated in a specific annular region that is more tolerant to misalignment and gaps compared to a uniform flat surface contact.
2Object-affected harmful factors
If higher manufacturing precision is provided to eliminate gaps, then noise reduction is achieved, but production cost increases
Solution Approach 1:
The invention changes the geometric parameters of the junction surfaces by introducing a shallow concave cone in the core and a perimeter relief in the plunger. These parameter changes create an annular contact region that concentrates magnetic attraction, thereby reducing noise without requiring high manufacturing precision. The geometric modification allows tolerance to gaps and misalignment while maintaining quiet operation.
3Speed
If softer magnetic materials are used to reduce retained magnetism, then response speed is improved, but manufacturing difficulty increases due to cold-working constraints
Solution Approach 1:
The invention creates a specific local geometry (annular contact region via concave cone and perimeter relief) that concentrates magnetic attraction where needed. This allows the use of softer magnetic materials throughout the core and plunger for faster response, because the localized geometric feature ensures sufficient magnetic force concentration without requiring hard materials for structural strength.
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 effectively reduces noise levels in solenoids, maintaining stability and magnetic force even with misalignment or debris, while allowing for lower production costs and reduced coercive force, thus enhancing operational reliability and quiet operation.
Implementation Method 1
the shading ring having an outside diameter slightly smaller than the diameter of the core, and operable to produce a concentration of magnetic attraction within an annular range of the interface between a center of the interface and a location of the shading ring
Implementation Method 2
concentrate magnetic attraction within an annular contact region, enhancing stability and reducing noise by improving magnetic force distribution
Data Source
AI summary
A solenoid may include a core having a junction surface; a plunger having a junction surface and located adjacent to the core; a shading ring located proximate to an interface between the core junction surface and the plunger junction surface, the shading ring having an outside diameter slightly smaller than the diameter of the core, and operable to produce a concentration of magnetic attraction within an annular range of the interface between a center of the interface and a location of the shading ring; wherein a contact region between the core junction surface and the plunger junction surface is substantially smaller than the respective junction surfaces and located proximate to the annular range of the concentration of magnetic attraction.