Piezoelectric Fluid Pump Bending Vibration for Compact High Flow
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Solution Overview
Problem
Piezoelectric pumps face limitations in reducing size while maintaining flow rate and pressure capabilities, and generating audible sound due to low operating frequencies when trying to increase diaphragm size for higher flow rates.
Innovation Solution
A fluid pump design featuring an actuator with a central and peripheral portion that performs bending vibrations without restraint, accompanied by a planar section and center vents, allowing for high pressure and flow rate generation in a compact, low-profile form.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the diaphragm size is increased to enhance flow rate and pressure capabilities, then the pumping capabilities are improved, but the size of the entire fluid pump increases and audible sound is generated due to low operating frequency
Solution Approach 1:
The patent applies mechanical vibration by driving the diaphragm at high frequency (20 kHz or higher) to generate acoustic waves that move fluid through the pump. This high-frequency vibration enables compact pump design while maintaining flow rate capabilities, as the rapid oscillations create effective fluid transport without requiring large diaphragm dimensions
Solution Approach 2:
The patent changes the operating frequency parameter to 20 kHz or higher, transitioning from low-frequency to high-frequency operation. This parameter change allows the pump to achieve the required flow rate with a smaller diaphragm area, resolving the contradiction between flow rate and pump size
2Productivity
If the diaphragm size is increased to enhance flow rate and pressure capabilities, then the pumping capabilities are improved, but audible sound is generated due to low operating frequency
Solution Approach 1:
The patent uses high-frequency mechanical vibration (20 kHz or higher) to drive the diaphragm, which generates ultrasonic waves rather than audible sound. This frequency selection moves the operation above the human audible range while maintaining effective fluid pumping capability
Solution Approach 2:
By changing the operating frequency to 20 kHz or higher, the patent transitions from audible frequency range to ultrasonic range, eliminating audible sound generation while maintaining flow rate performance
3Volume of moving object
If the pump size is reduced to meet miniaturization requirements, then the pump becomes more compact, but the flow rate and pressure capabilities decrease
Solution Approach 1:
The patent employs high-frequency mechanical vibration to achieve fluid pumping in a compact configuration. The rapid oscillations create effective fluid transport through acoustic radiation pressure and streaming effects, enabling small pump size while maintaining flow rate capabilities
Solution Approach 2:
The patent changes the driving frequency to 20 kHz or higher, which enables compact pump design. The high-frequency operation allows the pump to achieve required flow rates with smaller diaphragm area and overall pump dimensions
4Volume of moving object
If the pump size is reduced to meet miniaturization requirements, then the pump becomes more compact, but the pressure capabilities decrease
Solution Approach 1:
The patent uses high-frequency mechanical vibration to generate acoustic radiation pressure that drives fluid flow and overcomes back pressure. The rapid oscillations create effective pressure differentials that enable compact pump design while maintaining pressure capabilities
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 achieves high pressure levels and large flow rates in a small-sized, low-profile pump by minimizing vibration losses and optimizing pressure and flow rate generation through controlled bending vibrations and vent configurations.
Implementation Method 1
A voltage having a predetermined frequency is applied to the piezoelectric element 23 so as to cause a portion of the diaphragm 20 that faces the first opening 11 and a portion of the diaphragm 20 that faces the second opening 12 to bend and deform in directions opposite to each other
Implementation Method 2
an actuator including a central portion and a peripheral portion which is not substantially restrained, the actuator performing a bending vibration from the central portion to the peripheral portion
Data Source
Figure 1(a)~2B
Figure 3a~5
Figure 6~7
AI summary
A small-sized, low-profile fluid pump (101) having high pumping capabilities is formed. The fluid pump (101) includes an actuator (40) and a planar section (51) made of a metal plate. The actuator (40) is formed by attaching a disk-like piezoelectric element (42) to a disk-like diaphragm (41). By the application of a square-wave or sine-wave drive voltage, the actuator (40) performs a bending vibration from the central portion to the peripheral portion. The peripheral portion of the actuator (40) is not restrained. The actuator (40) performs a bending vibration in the state in which it is in proximity to the planar section (51) while facing the planar section (51). A center vent (52) is provided at or near the center of an actuator facing area of the planar section (51) that faces the actuator (40).