Piezoelectric Micro-Blower Side Outlet Design
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Solution Overview
Problem
Piezoelectric micro-blowers with compressive fluid discharge orthogonal to the blower body are not suitable for low-profile electronic devices due to space constraints and fail to generate flow when driven at high frequencies, even with side openings.
Innovation Solution
A piezoelectric micro-blower design with a blower chamber diameter less than half a wavelength of the pressure wave at the drive frequency, allowing uniform pressure change and fluid discharge to the side, reducing the device's height and enabling horizontal fluid flow within the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the piezoelectric micro-blower discharges fluid orthogonal to the blower body, then the fluid discharge direction is simplified, but the device requires vertical space and cannot be used in low-profile electronic devices
Solution Approach 1:
The patent changes the fluid discharge direction from vertical (orthogonal to blower body) to horizontal (parallel to blower body surface) by providing an outlet on the side wall of the blower chamber. This dimensional change allows the micro-blower to be mounted horizontally within low-profile devices without requiring vertical space for fluid discharge.
2Object-affected harmful factors
If the piezoelectric micro-blower is driven at high frequency, then drive noise is reduced, but no flow is generated when side openings are provided
Solution Approach 1:
The patent optimizes the blower chamber diameter to be less than half a wavelength of the pressure wave at the drive frequency. This parameter change ensures that at high frequencies (15 kHz or higher), the pressure waves can effectively propagate and generate flow through the side outlet, resolving the contradiction between high-frequency operation for noise reduction and flow generation capability.
3Productivity
If the blower chamber diameter is large, then more fluid can be discharged, but uniform pressure change cannot be achieved at high frequencies
Solution Approach 1:
The patent specifies that the blower chamber diameter should be less than half a wavelength of the pressure wave at the drive frequency. This parameter constraint ensures that pressure waves can uniformly distribute throughout the chamber at high frequencies, achieving uniform pressure change while still allowing adequate fluid discharge through the side outlet.
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 allows for significant reduction in the occupied space by the micro-blower, enabling its use in low-profile devices while maintaining efficient fluid discharge and cooling performance.
Implementation Method 1
A piezoelectric element 3 is attached to the center of the backside of the diaphragm 2. Applying a voltage to the piezoelectric element 3 causes the diaphragm 2 to bend and change the distance between the first opening 5a and the diaphragm 2.
Implementation Method 2
The blower chamber diameter is less than half a wavelength of a pressure wave at a drive frequency of the diaphragm, thereby allowing internal pressure to be substantially uniformly changed by vibration of the diaphragm in a state where the piezoelectric element is driven by an alternating voltage of about 15 kHz or higher.
Data Source
Figure 1(a)~2
Figure 3
Figure 4(A)~4(G)
AI summary
A vibration plate assembly (10) is formed by attaching a piezoelectric element (12) to a diaphragm (11), with an intermediate plate (13) interposed therebetween. A blower chamber plate (40) has a circular opening (40S) in a center thereof. A blower chamber (BS) formed by the diaphragm (11), a flow path plate (50), and the opening (40S) of the blower chamber plate (40) is sized to allow internal pressure to be substantially uniformly changed by vibration of the diaphragm. The blower chamber plate (40) and the flow path plate (50) are provided with an outlet (40BH) and an outlet (50BH), respectively. Compressive fluid pressurized in the blower chamber BS is blown out through the outlets (40BH and 50BH).