Self-Piercing Rivet Alignment and Ultrasonic Vibration
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Solution Overview
Problem
Vibration-assisted punch riveting methods often result in unwanted welding between the rivet and non-vibrating components due to contact, and require high process forces, limiting material compatibility and increasing wear.
Innovation Solution
A punch riveting device with alignment means on the rivet and punch, utilizing ultrasonic vibrations and vacuum locking to precisely align and hold the rivet without contacting non-vibrating components, reducing wear and process forces by using alignment recesses and bumps, and an ultrasonic system with a sonotrode for efficient material deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If vibration-assisted punch riveting is used to reduce process forces, then the force required to press in the rivet is reduced, but unwanted welding occurs between the rivet and non-vibrating components due to contact
Solution Approach 1:
A holder component is introduced as an intermediary between the rivet and the die. The holder receives ultrasonic vibrations and transmits them to the rivet, while the die remains stationary and free of vibrations. This mediator prevents direct contact between the vibrating rivet and the non-vibrating die, eliminating unwanted welding while maintaining the force-reducing benefits of vibration-assisted riveting
Solution Approach 2:
The system is segmented into distinct vibration zones: the holder and rivet form a vibrating component that receives ultrasonic vibrations, while the die remains a separate non-vibrating component. This segmentation allows the rivet to vibrate for reduced process forces while preventing vibration transmission to the die, avoiding harmful welding effects
2Manufacturing precision
If the rivet is held and aligned during punch riveting, then alignment precision is improved, but the rivet may contact non-vibrating components causing welding
Solution Approach 1:
The holder acts as an intermediary alignment and vibration transmission device. It provides alignment features (such as alignment pins or guides) that precisely position the rivet relative to the die, while simultaneously transmitting ultrasonic vibrations to the rivet. This ensures the rivet is both precisely aligned and vibrated, preventing contact welding with the non-vibrating die
3Object-affected harmful factors
If conventional punch riveting is used without vibration, then no unwanted welding occurs, but very high process forces are required
Solution Approach 1:
Ultrasonic vibrations are applied to the rivet through the holder during the punch riveting process. These high-frequency mechanical vibrations reduce the force required to deform and join the metal sheets by approximately 30-50%, while the holder design ensures vibrations are confined to the rivet-holder system and do not cause welding with the stationary die
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 ensures precise alignment and holding of punch rivets during vibration-assisted riveting, preventing unwanted welding, reducing wear, and lowering process forces, expanding material compatibility and improving material separation in lightweight automotive construction and mixed-material applications.
Implementation Method 1
a vibration generator, such as an ultrasonic generator, is used to move one or more components when connecting the components to set in motion. This vibration reduces, for example, the force required to press in the rivet
Implementation Method 2
the rivet can be held in a vacuum channel in the punch by negative pressure
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a self-piercing rivet (10) with a rivet head (12) and a rivet shank (13) adjoining it, wherein the rivet head (12) has a rivet-side alignment means (11) which can cooperate with a punch-side alignment means (154) of a self-piercing rivet die (15) in order to align the self-piercing rivet (10) relative to the self-piercing rivet die (15), and to a corresponding self-piercing rivet die (15) of a self-piercing riveting device for setting self-piercing rivets (10) into joining partners (20, 21), which self-piercing rivet die (15) has a punch-side alignment means (154) for cooperating with a rivet-side alignment means (11) of a self-piercing rivet (10).