Fan Cap Snap-Fit Mechanism for Vibration Damping
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Solution Overview
Problem
Fans in air/gas mixing systems for burners in heating equipment generate noise due to vibrations caused by thermal expansion differences between materials and the fixing system of the motor control printed circuit board cap, which amplifies sound waves and requires additional fixing elements, leading to increased assembly costs and noise.
Innovation Solution
A centrifugal fan design featuring a plastics frame with snap-fitting interlocking mechanisms to secure the cap to the motor support, eliminating the need for additional fixing elements and reducing thermal expansion-related vibrations, thereby minimizing noise generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If additional fixing elements (screws or hooks) are used to secure the cap to the motor support, then the cap is firmly fixed, but the assembly process becomes more complex and costly
Solution Approach 1:
The fixing elements are integrated directly into the cap structure as unitary plastic components, merging the cap and fixing elements into a single piece that reduces assembly complexity while maintaining stable fixation
Solution Approach 2:
The cap structure includes self-contained fixing elements that automatically engage with the motor support during assembly, eliminating the need for separate fixing operations and reducing assembly steps
2Object-affected harmful factors
If materials of different types (plastics cap and metal motor support) are connected, then the cap provides protection, but thermal expansion differences cause variation in assembly state and generate vibrations
Solution Approach 1:
A vibration damping element made of elastomeric material is introduced as an intermediary between the plastic cap and metal motor support, absorbing thermal expansion stresses and preventing vibration transmission while maintaining the protective function
Solution Approach 2:
The solution combines different materials (plastic cap, elastomeric damping element, metal support) into a composite assembly that leverages the properties of each material to achieve both protection and vibration reduction
3Stability of the object's composition
If the cap is fixed rigidly to the motor support, then structural stability is improved, but noise is amplified due to the box-shaped formation acting as a resonator
Solution Approach 1:
The vibration damping element serves as a mediator that decouples the cap from rigid structural connections, reducing noise transmission while maintaining sufficient structural stability for the protective function
Solution Approach 2:
The elastomeric vibration damping element acts as a flexible intermediary that absorbs vibrations and prevents the cap from acting as a noise amplifier, while still providing structural support
4Object-generated harmful factors
If vibration damping elements are used to reduce noise, then vibrations are dampened, but the system becomes more complex with additional components
Solution Approach 1:
The vibration damping function is merged into the cap assembly as an integrated component rather than a separate accessory, reducing overall system complexity while maintaining vibration reduction capabilities
Solution Approach 2:
The vibration damping element is positioned and secured through the cap's own structure during normal assembly operations, eliminating the need for separate installation steps and reducing system 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 solution effectively reduces noise by decoupling the cap from vibrations, lowers assembly costs, and simplifies the assembly process by using a resilient snap-fitting connection that maintains stability without tension forces, addressing the noise and cost issues associated with traditional fixing systems.
Implementation Method 1
a motor support which comprises a metal frame for mounting vibration damping elements, which is fixedly joined to the plate
Implementation Method 2
The vibration damping elements which are also known using the term 'silent block' are fixed, for example, with screws, to the above-mentioned frame so as to remain interposed between the motor and the motor support plate in order to reduce the transmission of vibrations to the structure of the fan
Implementation Method 3
interconnection means and counter-means which are provided on the cap and on the fixing frame, respectively, and which mutually cooperate in order to fix the cap to the fan by means of the fixing frame
Data Source
Figure 1
Figure 1A~1B
Figure 2
AI summary
There is described a fan for air/gas mixing systems in burners of heating equipment, comprising a fan impeller (2) which is received in a volute (3) which is provided with a motor support plate (4), a motor (5) on the shaft (5a) of which the impeller (2) is keyed, a motor support comprising a first metal frame (6) for mounting vibration damping elements (7), a motor control (5) printed circuit board (8) which is positioned near the motor, and a protection and containment cap (10) of the board/motor assembly, wherein the first frame (6) is fixedly joined to the plate (4) and the motor (5) is supported on the first frame (6) with the vibration damping elements (7) being interposed, and wherein the cap (10) is produced from plastics material and the fan comprises a second frame (11) of plastics material which can be connected to the first metal frame (6) and interconnection means and counter-means which are provided on the cap (10) and on the second frame (11), respectively, and which mutually cooperate in order to fix the cap to the fan by means of the second frame.