Fan Frame Structure Resisting Overmolding Deformation
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Solution Overview
Problem
Centrifugal fan frames with metal bases experience deformation due to the wrapping force from overmolded plastic side walls, affecting clearance size, horizontality, balance, and fan performance.
Innovation Solution
The fan frame structure incorporates extension sections on the metal base with connecting sides and insert-molded wall segments, including clearances between adjacent segments to resist deformation by allowing expansion without pressing against the base.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metal base is used for the fan frame, then structural strength is improved, but deformation occurs due to wrapping force from overmolded plastic side walls
Solution Approach 1:
The side wall is divided into multiple wall segments (first wall segment, second wall segment, third wall segment) instead of a single continuous overmolded structure. This segmentation allows each segment to independently manage the wrapping force, preventing cumulative deformation of the metal base while maintaining overall structural integrity.
Solution Approach 2:
Different wall segments are positioned at specific locations (first side, second side, third side) of the extension section, creating localized reinforcement zones. This local quality approach allows the structure to resist wrapping force at critical areas without requiring uniform reinforcement throughout, reducing overall deformation risk.
2Ease of manufacture
If plastic side walls are overmolded onto the metal base, then ease of manufacture is improved, but the wrapping force deforms the metal base
Solution Approach 1:
The side wall is segmented into multiple independently molded wall segments that are assembled onto the metal base. This segmentation reduces the total wrapping force applied at any single location, preventing base deformation that would otherwise affect clearance precision, while still using injection molding for ease of manufacture.
Solution Approach 2:
The metal base is pre-formed with extension sections that have predetermined geometric features before the wall segments are attached. This preliminary action ensures that the base structure is optimized to resist wrapping force from multiple segments, maintaining manufacturing precision for clearances while enabling easy assembly of the segmented wall structure.
3Strength
If the base portion is deformed by wrapping force, then fan frame structural strength is improved through metal material, but fan performance deteriorates due to interference
Solution Approach 1:
By segmenting the side wall into multiple sections attached at different locations, the wrapping force is distributed and reduced at each attachment point. This prevents base deformation that would cause fan blade interference, maintaining both the structural strength benefits of metal and the performance reliability of the fan.
Solution Approach 2:
Wall segments are strategically positioned at specific locations (first side, second side, third side) where wrapping force is most likely to occur. This local reinforcement approach maintains the overall structural strength of the metal fan frame while preventing localized deformations that would interfere with fan blade operation and degrade performance.
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 design enhances the structural strength of the fan frame, preventing deformation and maintaining the intended clearance and balance between fan blades and the base, thereby improving fan performance and reducing noise and airflow interference.
Implementation Method 1
the overmolding plastic material tends to produce a wrapping force after the material is molded, and the metal base subjected to the wrapping force tends to be pressed and deformed
Data Source
AI summary
A fan frame structure includes a base portion and a wall portion. The base portion has at least one extension section vertically extended from an outer peripheral edge of the base portion, and the extension section has connecting sides. The wall portion is formed along the outer peripheral edge of the base portion through an insert molding process. The wall portion includes a plurality of wall segments connected to the connecting sides of the extension sections, and a clearance is formed between any two adjacent wall segments. With these arrangements, the base portion can better resist a wrapping force from the insert-molded wall portion to avoid deformation.