Centrifugal Fan Bonding Structure for Thermal Misalignment Control
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Solution Overview
Problem
Centrifugal fans experience misalignment of the center of gravity due to thermal deformation, affecting fan balance and causing vibration and noise, especially when different materials with varying thermal expansion coefficients are used for the fan unit and fixing member.
Innovation Solution
A centrifugal fan design with a rotor yoke and fan unit configuration that includes a first portion with a flat surface and tubular shape, and a second portion with annular and auxiliary rib portions, allowing for a clearance between tubular portions and enhanced adhesive bonding to reduce thermal deformation misalignment and maintain strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the fan unit and fixing member are bonded directly without additional structures, then the bonding process is simple, but the bonding strength is insufficient and thermal deformation causes misalignment
Solution Approach 1:
The fixing member is segmented into a flat surface portion and a tubular portion, with the flat surface portion specifically designed for bonding to the fan unit. This segmentation allows the bonding interface to be optimized separately from the structural support functions, enabling strong bonding while maintaining overall structural integrity and thermal stability.
Solution Approach 2:
The invention transitions from a simple radial bonding interface to a multi-dimensional bonding structure by adding the flat surface portion that extends axially. This creates a larger bonding area in multiple dimensions, improving bonding strength and thermal deformation resistance without significantly increasing overall device complexity.
2Ease of manufacture
If the fan unit is made of resin material, then the manufacturing flexibility is improved, but the thermal expansion coefficient increases causing greater thermal deformation
Solution Approach 1:
The flat surface portion of the fixing member acts as an intermediary between the resin fan unit and the metal tubular portion. This intermediary structure provides a stable bonding interface that compensates for the high thermal expansion of the resin material, maintaining dimensional stability while allowing the use of easily manufacturable resin fan units.
Solution Approach 2:
The invention changes the geometric parameters of the fixing member by adding the flat surface portion with specific dimensions. This parameter change creates a bonding interface that is optimized for thermal stability, allowing the resin fan unit to be manufactured easily while compensating for thermal expansion through the designed bonding structure.
3Reliability
If the bonding area is increased to prevent misalignment, then the bonding strength improves, but the device complexity increases
Solution Approach 1:
The fixing member is divided into distinct functional portions: the flat surface portion dedicated to bonding and the tubular portion for structural support. This segmentation increases the effective bonding area without adding overall structural complexity, as each portion serves its specific function efficiently.
Solution Approach 2:
The flat surface portion serves multiple functions: it provides a large bonding area for strong adhesion, acts as a thermal buffer to reduce deformation, and maintains alignment during operation. This multi-functionality increases reliability without proportionally increasing device complexity.
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 reduces misalignment of the center of gravity due to thermal deformation while ensuring strong bonding, thereby minimizing vibration and noise, and enhancing the fan's operational stability.
Implementation Method 1
A bonding portion formed of an adhesive is provided between each of the annular end surface of the annular rib portion and the end surfaces of the plurality of auxiliary rib portions and the flat surface
Implementation Method 2
the fan unit and the fixing member are often made of different materials, and for example, as in Patent Literature 1, the fan unit may be made of resin, and the fixing member may be made of metal. As described above, when the fan unit is formed of the material having a greater linear coefficient of expansion than that of the fixing member
Data Source
AI summary
A centrifugal fan includes a first portion in a rotor, and a second portion in a fan unit and having a greater linear coefficient of expansion than that of the first portion. The first portion has a top portion having a flat surface and a first tubular portion. The second portion has a main portion located in a first axial direction with respect to the top portion, a second tubular portion having an inner tube surface facing the outer tube surface of the first tubular portion with a clearance therebetween, an annular rib portion protruding from the main portion in a second axial direction, and a plurality of auxiliary rib portions. A bonding portion of an adhesive is provided between each of an annular end surface of the annular rib portion and the end surfaces of the plurality of auxiliary rib portions facing the flat surface, and the flat surface.