Piezoelectric Microblower Helmholtz Resonance Compact Design
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Solution Overview
Problem
Existing piezoelectric microblowers face challenges in achieving a compact size while maintaining a high flow rate and minimizing noise, as reducing the size of the vibrating plate leads to decreased displacement and flow rate, and operating frequencies within the audible range result in noise issues.
Innovation Solution
A piezoelectric microblower design that includes a vibrating plate driven in a bending mode with a blower body forming a resonance space by a partition, where the resonant frequency of the blower chamber matches the driving frequency of the vibrating plate, allowing for Helmholtz resonance beyond the audible range, and a partition is used to create a smaller resonance space independent of the blower chamber dimensions, enabling a compact and high-flow-rate design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the size of the vibrating plate is reduced to make the blower more compact, then the blower size is reduced, but the displacement is markedly reduced and the flow rate decreases
Solution Approach 1:
The invention utilizes resonance vibration of the air in the blower chamber at the same frequency as the vibrating plate to amplify the air flow effect. By matching the driving frequency of the small vibrating plate with the resonant frequency of the air in the blower chamber, the system achieves high flow rate despite the small size of the vibrating plate, as the resonance amplifies the displacement effect throughout the entire chamber volume.
Solution Approach 2:
The invention changes the operating parameters by tuning the driving frequency of the vibrating plate to match the resonant frequency of the air in the blower chamber. This frequency parameter adjustment allows the system to operate at resonance, where the air molecules naturally oscillate with maximum amplitude, compensating for the small displacement of the reduced-size vibrating plate and maintaining high flow rate.
2Productivity
If the driving frequency is set within the audible range to achieve first-order resonance mode with maximum displacement, then the flow rate is maximized, but noise becomes large
Solution Approach 1:
The invention changes the frequency parameter from the audible range to the ultrasonic range (beyond human hearing). By operating at ultrasonic frequencies while maintaining resonance conditions, the system achieves the desired flow rate without generating audible noise, as the vibration frequency is above the human audible limit of 20 kHz.
Solution Approach 2:
The invention utilizes resonance vibration at ultrasonic frequencies to drive the air flow. By matching the ultrasonic driving frequency with the resonant frequency of the air in the blower chamber, the system achieves efficient air movement through resonance amplification without producing audible noise, since the vibration occurs beyond the human audible range.
3Object-generated harmful factors
If the third-order resonance mode is used to operate beyond the audible range and reduce noise, then noise is minimized, but the displacement is smaller and flow rate decreases
Solution Approach 1:
The invention utilizes resonance vibration of the air in the blower chamber to amplify the air flow effect. By matching the driving frequency with the resonant frequency of the air, the system achieves high flow rate despite using vibration modes with smaller displacement, as the resonance amplifies the effect throughout the entire chamber volume.
Solution Approach 2:
The invention exploits the compressibility and resonance characteristics of air (a gas) in the blower chamber. By tuning the driving frequency to match the resonant frequency of the air column, the system uses pneumatic resonance to amplify the air flow effect, compensating for the smaller displacement of the vibrating plate and achieving high flow rate without requiring large mechanical displacement.
4Productivity
If the resonant frequency of the air in the blower chamber is matched with the driving frequency to utilize resonance, then the flow rate is improved, but the blower chamber dimensions constrain the design flexibility
Solution Approach 1:
The invention segments the blower chamber into a resonance space by introducing a partition structure. This partition creates a dedicated resonance cavity with controlled dimensions that can be independently optimized for resonance, while the rest of the blower chamber can be designed for other functional requirements. This segmentation allows the resonance characteristics to be tuned without constraining the overall blower design.
Solution Approach 2:
The invention applies local quality by creating a specific resonance space with particular dimensional characteristics within the blower chamber. The partition structure defines a localized region with optimized resonance properties, while other regions of the blower can have different characteristics suited for their specific functions, thereby maintaining overall design flexibility.
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 achieves a compact microblower with improved flow rate and reduced noise by utilizing resonance beyond the audible range, allowing for efficient air flow without inhibiting vibration, thus addressing the limitations of size and noise in existing technologies.
Implementation Method 1
a piezoelectric element; a vibrating plate that is driven in a bending mode by applying a voltage of a predetermined frequency to a piezoelectric element
Implementation Method 2
a resonance space is formed inside of the partition and a size of the resonance space is set such that the driving frequency of the vibrating plate and the Helmholtz resonance frequency of the resonance space correspond to each other
Implementation Method 3
a vibrating plate that is driven in a bending mode by applying a voltage of a predetermined frequency to a piezoelectric element
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
[Object] To provide a piezoelectric microblower that can be made compact while still attaining good blower characteristics. [Solution] In part of a blower chamber 4 corresponding to a central portion of a vibrating plate 50, a resonance space 34 is formed by providing a partition 33 around an opening 31 and the size of the resonance space 34 is set such that the driving frequency of the vibrating plate 50 and the Helmholtz resonant frequency of the resonance space 34 correspond to each other. A gap δ is formed between the partition 33 and the vibrating plate 50 so that there is no contact therebetween when the vibrating plate is displaced. An increase in the flow rate can be attained by utilizing resonance of air.