Ultrasonic Self-Piercing Riveting With Force-Gradient Control
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Solution Overview
Problem
Conventional punch riveting methods require high forces and lack efficient control mechanisms for quality assessment, especially during the transition between different phases of the riveting process.
Innovation Solution
The method employs an ultrasonic punch riveting device that uses a vibration generator to reduce the force required for rivet insertion, with the gradient of the force serving as a control variable to adjust parameters like frequency, amplitude, and feed rate, allowing for precise phase transitions and energy management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional punch riveting methods are used, then the joining process is simple, but high forces are required and quality assessment is difficult
Solution Approach 1:
The patent applies ultrasonic vibration to the punch during the riveting process. The vibration generator creates high-frequency oscillations that reduce friction and enable the rivet to be inserted with significantly lower forces compared to conventional punch riveting, directly resolving the contradiction between required force and process effectiveness
Solution Approach 2:
The patent implements a control system that continuously monitors the force gradient during rivet insertion and uses this feedback to dynamically adjust vibration parameters (amplitude, frequency) and feed rate. This closed-loop control enables precise quality assessment and optimization of the joining process while maintaining low force requirements
2Force
If vibration is applied during riveting, then force required is reduced, but control of vibration parameters becomes necessary
Solution Approach 1:
The control system monitors the force gradient in real-time and automatically adjusts vibration amplitude, frequency, and feed rate based on the measured force characteristics. This automated feedback control eliminates the need for manual parameter adjustment while maintaining optimal low-force conditions throughout the riveting process
Solution Approach 2:
The system uses the force gradient information from the riveting process itself to automatically regulate its own vibration parameters. The process data generated during riveting is directly utilized to control the vibration generator, creating a self-regulating system that maintains optimal conditions without external intervention
3Manufacturing precision
If force gradient is used as control variable, then phase transitions are precise, but measurement and control complexity increases
Solution Approach 1:
The patent replaces complex multi-sensor measurement systems with a simplified approach that uses the existing force measurement data. By calculating the force gradient from standard force-vs-position measurements, the system achieves precise phase transition detection without requiring additional complex measurement infrastructure
Solution Approach 2:
The system transforms the standard force measurement parameter into a force gradient parameter through mathematical differentiation. This parameter transformation enables precise detection of phase transitions (piercing, spreading, setting) using the same measurement hardware, avoiding the need for additional sensors or measurement systems
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 approach reduces the force needed for rivet insertion, enhances connection quality, and enables precise control of the riveting process by utilizing the force gradient to adjust vibration parameters, improving the overall efficiency and accuracy of the punch riveting process.
Implementation Method 1
at least one component involved in pressing the rivet, which in particular comprises the punch, is set into vibration during pressing by means of a vibration generator. The vibrations can in particular be transmitted or coupled to the component by means of a vibration converter excited by the vibration generator. A frequency converter or similar device is particularly suitable as the vibration generator. A sound generator, particularly an ultrasonic generator, is used, with an electromechanical converter such as a piezoelectric converter serving as the vibration converter.
Implementation Method 2
A sound generator, particularly an ultrasonic generator, is used, with an electromechanical converter such as a piezoelectric converter serving as the vibration converter.
Data Source
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Figure 3a~3b
AI summary
The invention relates to a method for joining at least two components using a self-piercing riveting device, in which the at least two components are arranged between a punch and a counter-holder, wherein a rivet arranged between the punch and a component of the at least two components facing the punch is pressed into the at least two components by means of the punch by applying a force (F) to the punch, wherein at least one component involved in pressing the rivet is set into vibration by means of a vibration generator during pressing, wherein a gradient (dF/dx) of the force is determined at least temporarily during pressing the rivet, and wherein at least one parameter of the vibration to be generated by means of the vibration generator is specified at least temporarily taking into account the gradient (dF/dx) of the force, as well as such a self-piercing riveting device.