Integrated Bolt Ultrasonic Converter for High-Amplitude Service Life
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Solution Overview
Problem
Conventional ultrasound swing unit converters face challenges in generating high amplitudes while maintaining a long service life, often resulting in material cracks and reduced vibration quality due to stress concentrations at thread connections.
Innovation Solution
A converter design where the bolt and converter base are formed as a single piece with a transition radius greater than 0.5 mm, incorporating a distance disc with a high surface quality and asymmetrical saw thread, and strategically positioned piezo elements to enhance vibration transmission and reduce material stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a bolt with threaded connection is used to clamp piezo elements onto the converter base, then the assembly is secure and piezo elements are firmly held, but stress concentrations form at the thread connection leading to material cracks and reduced service life
Solution Approach 1:
The bolt and converter base are merged into a single integral component, eliminating the threaded connection interface that causes stress concentrations. This integration removes the weak point where cracks typically form, while maintaining the clamping function through the unified structure.
Solution Approach 2:
A transition radius R > 0.5 mm is introduced at the connection point where the bolt meets the converter base. This curved transition distributes stresses more evenly compared to sharp corners or abrupt transitions, preventing stress concentration and material fatigue.
2Reliability
If the preload force is reduced to extend service life, then material stress is decreased, but oscillation amplitude and oscillation quality deteriorate due to poorer coupling
Solution Approach 1:
By integrating the bolt and converter base, the connection becomes inherently more robust and uniform, allowing for better stress distribution even at lower preload levels. This eliminates the need to compromise oscillation quality to extend service life.
Solution Approach 2:
The transition radius creates a smoother stress distribution pattern that reduces peak stresses without requiring high clamp forces. This allows the piezo elements to be securely coupled to the converter base with reduced preload, extending service life while maintaining oscillation amplitude and quality.
3Volume of moving object
If an amplitude transformer is omitted to save space, then the device becomes more compact, but larger amplitudes cannot be generated without overstressing the converter
Solution Approach 1:
The integral bolt-converter base structure creates a more robust and stress-resistant connection that can handle higher vibration amplitudes directly at the converter level. This eliminates the need for an separate amplitude transformer component, achieving both compactness and high amplitude capability.
4Reliability
If special thread forms with undercut are used to control tension and increase service life, then reliability improves, but manufacturing complexity and cost increase
Solution Approach 1:
By eliminating the separate bolt and threaded connection, the complex thread form designs with undercuts are no longer needed. The integral structure achieves improved reliability through simpler geometry that is easier and less expensive to manufacture.
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 stabilizes the connection, reduces material stress, and improves vibration transmission, enabling high-amplitude operation with extended service life and reduced risk of piezo element damage.
Implementation Method 1
at least one piezo element with a through-hole... by applying an alternating electrical voltage to the piezo elements, the piezo elements stimulate a mechanical vibration
Implementation Method 2
The clamping element ensures that a mechanical vibration of the piezo element is transferred to the converter base part
Data Source
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AI summary
Disclosed is a converter having a main converter part, a bolt (4) that is connected to the main converter part, a bracing element, and at least one piezo element (6) with a through-hole that is penetrated by the bolt (4); the bracing element braces the at least one piezo element in the direction of the main converter part. The disclosed converter is characterized in that the bolt (4) is integrally bonded to the main converter part.