Sodium-Potassium Niobate Vibration Wave Motor for Temperature Stability
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Solution Overview
Problem
Existing vibration wave motors using lead-based piezoelectric materials face significant performance degradation due to temperature fluctuations, leading to inefficient driving and inconsistent voltage requirements, which affect driving efficiency and torque output.
Innovation Solution
Employing a lead-free piezoelectric body made of sodium-potassium niobate, combined with a metal mover and elastic body, to stabilize electrostatic capacitance and reduce temperature-related impedance changes, ensuring consistent driving performance across varying temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a vibration wave motor is designed to be compact and lightweight, then it can be suitable for portable devices, but it becomes difficult to secure the rotor and stator with high positional accuracy
Solution Approach 1:
The patent employs flexible adhesive layers to bond the rotor and stator in the radial direction. This flexible bonding method accommodates the compact design while maintaining sufficient positional accuracy, resolving the contradiction between miniaturization and manufacturing precision requirements.
2Ease of manufacture
If adhesive layers are used to secure the rotor and stator, then assembly is simplified, but the adhesive layers occupy space that would otherwise be available for increasing the diameter of the armature winding
Solution Approach 1:
The patent positions the adhesive layers at the radial ends of the rotor and stator, utilizing the radial dimension rather than consuming axial or tangential space. This dimensional arrangement allows adhesive bonding while preserving maximum space for armature winding diameter, resolving the contradiction between ease of manufacture and volume utilization.
3Length of moving object
If the vibration wave motor uses a compact design with small diameter, then it is suitable for portable equipment, but the motor output becomes insufficient
Solution Approach 1:
The flexible adhesive layers enable compact assembly while maintaining structural integrity, allowing the motor to achieve sufficient output within a small diameter constraint. The adhesive bonding secures the rotor-stator interaction necessary for vibration wave generation without requiring larger dimensional tolerances.
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 lead-free design maintains stable electrostatic capacitance and impedance, allowing for efficient driving performance across a wide temperature range, reducing noise and improving positioning accuracy without gear noise, and enhancing torque consistency.
Implementation Method 1
a piezoelectric element that generates vibration in the vibration piece when voltage is applied
Implementation Method 2
a vibration piece that generates sound waves by vibrating in a fluid medium
Data Source
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AI summary
A vibrator includes an electromechanical transducer which is a piezoelectric ceramic made of sodium-potassium niobate metal oxides and whose temperature characteristics of a relative permittivity is 500 [ppm/°C] or less in absolute value in a temperature range from -40°C to 170°C, wherein excitation of the electromechanical transducer produces a vibration wave. Another vibrator includes an electromechanical transducer which is a piezoelectric ceramic made of sodium-potassium niobate metal oxides and whose temperature characteristics of a relative permittivity is 390 [ppm/°C] or less in absolute value in a temperature range from 0°C to 60°C, wherein excitation of the electromechanical transducer produces a vibration wave.