Piezoelectric Actuator with Anisotropic Vibrating Plate
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Solution Overview
Problem
Existing piezoelectric motors using large piezoelectric devices face limitations in achieving significant driving force or rotation speed due to small flexural vibration of the piezoelectric device, necessitating larger actuators which are inefficient and power-intensive.
Innovation Solution
A piezoelectric actuator design featuring a vibrating plate with different Young's moduli in the urging and intersecting directions, formed using a rolling method to enhance flexural vibration efficiency, allowing for efficient vibration transmission to a driven member with a small piezoelectric device, and utilizing PZT material for high drive power and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a large piezoelectric device is used to increase driving force or rotation speed, then the driving force and rotation speed improve, but the device size and power consumption increase
Solution Approach 1:
The vibrating plate is designed with non-uniform thickness, being thinner at the vibration transmission portion and thicker at other portions. This local variation in thickness creates different Young's moduli in different regions and directions, allowing the plate to efficiently transmit flexural vibration while maintaining structural integrity, thereby achieving high driving force with a compact actuator size
Solution Approach 2:
The invention changes the physical parameters of the vibrating plate by controlling the thickness distribution and orientation relative to the rolling direction. By adjusting the thickness ratio between the vibration transmission portion and other portions, and by orienting the plate at specific angles (45-135 degrees) to the rolling direction, the Young's modulus ratio EL/ES is optimized to enhance flexural vibration efficiency without increasing actuator size
2Speed
If a large piezoelectric device is used to increase rotation speed, then the rotation speed improves, but the device complexity and power consumption increase
Solution Approach 1:
The vibrating plate utilizes a thin-film structure with controlled thickness variation to achieve efficient flexural vibration. The thin film design allows for high-frequency vibration transmission while maintaining structural stability, enabling high rotation speed without complex actuator structures
Solution Approach 2:
By optimizing the thickness ratio and orientation parameters of the vibrating plate, the invention achieves high rotation speed through enhanced flexural vibration efficiency. The parameter optimization (thickness ratio, orientation angle of 45-135 degrees to rolling direction) allows the simple plate structure to deliver high performance without increasing device complexity
3Reliability
If the Young's modulus in the urging direction is increased to improve vibration transmission, then the flexural vibration efficiency improves, but the manufacturing difficulty increases
Solution Approach 1:
The rolling method inherently creates a periodic microstructure in the plate material along the rolling direction. By orienting the vibrating plate at specific angles (45-135 degrees) to the rolling direction, the invention utilizes this periodic structure to achieve the desired Young's modulus ratio without complex manufacturing processes
Solution Approach 2:
The invention achieves the required Young's modulus characteristics by changing geometric parameters (thickness distribution, orientation angle) rather than material composition. The thickness ratio between the vibration transmission portion and other portions, combined with the orientation angle to the rolling direction, provides a manufacturable solution that delivers high vibration transmission efficiency
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 enables efficient drive of a driven member with improved flexural vibration ratio, reduced power consumption, and downsized drive circuits, resulting in compact, high-efficiency motors suitable for versatile robots and complex device assembly.
Implementation Method 1
a piezoelectric material stacked on the vibrating plate
Implementation Method 2
flexural vibration of the piezoelectric device rotates the driven member in a predetermined direction via the reinforcing plate
Data Source
AI summary
A motor includes a vibrating plate having a projection part to be pressed against a driven member and a piezoelectric material provided on the vibrating plate, wherein a Young's modulus EL in the pressing direction of the vibrating plate and a Young's modulus ES in a direction crossing the pressing direction are different.