Ultrasonic Vibration Unit with Damped Node Absorber
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Solution Overview
Problem
Ultrasonic welding devices experience reduced quality and excessive stress due to low-frequency parasitic vibrations, which also increase energy requirements and noise, especially when welding thin materials like salad bags.
Innovation Solution
A damped vibration damper unit is connected to the ultrasonic vibration unit at a vibration node, utilizing a damping element to selectively dampen low-frequency parasitic vibrations without affecting the desired working frequency, similar to an electromagnetic blocking circuit, where the coupling element is arranged at a node to minimize energy transfer from the working vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a damped vibration damper unit is connected at a vibration node to dampen parasitic oscillations, then parasitic vibrations are reduced, but the device complexity increases
Solution Approach 1:
A vibration damper unit is introduced as an intermediary component connected at a vibration node between the converter and sonotrode. This mediator specifically targets and dampens parasitic oscillations without interfering with the primary ultrasonic welding function, resolving the contradiction by adding a specialized component that addresses the harmful vibrations independently.
Solution Approach 2:
The vibration damper is strategically positioned at a vibration node where parasitic oscillations are most problematic. By applying damping locally at this specific location rather than throughout the entire system, the solution effectively reduces parasitic vibrations while minimizing the overall complexity added to the device.
2Productivity
If the sonotrode is excited at resonance frequency to maximize vibration amplitude, then welding efficiency is improved, but parasitic low-frequency vibrations are generated
Solution Approach 1:
The system operates at resonance frequency to maximize ultrasonic vibration amplitude for efficient welding. The vibration damper unit is specifically designed to target and dampen the resulting parasitic low-frequency vibrations, allowing the primary welding function to operate at optimal efficiency while the harmful byproduct vibrations are selectively suppressed.
3Loss of energy
If soft mounting with O-rings is used to decouple the ultrasonic unit from the converter housing, then energy transmission to the housing is reduced, but parasitic vibrations are not fully eliminated
Solution Approach 1:
The soft O-ring mounting serves as a first intermediary that decouples the ultrasonic unit from the converter housing, reducing energy transmission. A second intermediary, the vibration damper unit connected at the vibration node, is added to specifically target and eliminate parasitic vibrations that the O-ring mounting alone cannot fully suppress.
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 solution effectively reduces parasitic oscillations, maintaining the quality of the welding process while minimizing energy consumption and noise, by efficiently transferring energy from parasitic vibrations to damping elements, thus converting it into thermal energy.
Implementation Method 1
the converter 12, which has a piezoelectric oscillating module
Implementation Method 2
the vibration damper unit being connected to a damping element which is designed in such a way that it damps vibration of the vibration damper unit
Implementation Method 3
When the ultrasonic oscillating unit is excited with this natural frequency, a standing longitudinal wave forms in the entire ultrasonic oscillating unit with stationary oscillation nodes and antinodes
Data Source
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AI summary
The present invention relates to an ultrasonic vibration unit which has a converter (1) for converting an electrical alternating voltage into mechanical ultrasonic vibration, and a sonotrode which has a vibration coupling to the converter (1), wherein the sonotrode and the converter (1) are coordinated with one another in such a way that the ultrasonic vibration unit can vibrate with a natural frequency f at which a standing longitudinal wave with at least one vibration node and at least two vibration antinodes forms inside the ultrasonic vibration unit. In order to make available an ultrasonic vibration unit in which the parasitic vibrations which usually occur at a working frequency during operation are low or do not occur, wherein at the same time the actual working vibration is not attenuated, the invention proposes that a damped vibration absorber unit (2) is provided which is connected to the ultrasonic vibration unit via a coupling element (3), wherein the coupling element (3) is connected to the ultrasonic vibration unit at a vibration node, wherein the vibration absorber unit (2) is connected to a damping element (4) which is embodied in such a way that it damps a vibration of the vibration absorber unit (2).