Expandable Polyurethane Bonding for Plastic Assembly Vibration Damping
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Solution Overview
Problem
Existing methods for assembling plastic products to resist or absorb vibrations and shocks are hindered by the poor elastic properties of glue layers, which can lead to cracking and weakened connections, and are often complex and costly due to the use of fastening means like screws, which also negatively affect vibration damping properties.
Innovation Solution
A method involving the application of an expandable polymer material to complementary supporting surfaces, allowing it to set and expand, thereby bonding the elements without fastening means, enhancing the elastic properties and shock absorption while reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a glue layer is used to bond plastic elements, then the bonding process is simple, but the elastic properties are poor leading to cracking and weakened connections under vibration and shock
Solution Approach 1:
The patent changes the material parameters by using a two-component polyurethane system that expands during curing. This expansion transforms the material from a simple adhesive into a structural bonding agent that fills gaps and creates a mechanically interlocked connection, significantly improving elastic properties and resistance to vibration while maintaining ease of application
Solution Approach 2:
The patent employs a composite bonding system where expanded polyurethane foam integrates with rigid plastic elements. The foam's cellular structure provides elasticity and shock absorption, while the rigid elements provide structural strength, creating a composite connection that overcomes the limitations of simple glue layers
2Reliability
If plastic foam is applied and fastening means like screws are used to connect elements, then shock and vibration absorption is improved, but the production process becomes complex and costly
Solution Approach 1:
The patent extracts and eliminates the fastening means (screws, clips, or other mechanical connectors) from the assembly process. The expanded polyurethane foam alone provides both the bonding function and the shock/vibration absorption, removing the need for separate fastening components and simplifying the production process while maintaining reliability
Solution Approach 2:
The expanded polyurethane foam performs multiple functions simultaneously: it acts as the bonding agent, provides shock and vibration absorption, fills gaps between elements, and creates a mechanically interlocked connection. This multi-functionality replaces what would otherwise require multiple separate components and processes
3Strength
If fastening means like screws are used to connect elements, then the connection strength is improved, but vibration damping properties are negatively affected by solid-borne sound transmission
Solution Approach 1:
The expanded polyurethane foam serves as an intermediary material between the rigid plastic elements. It provides mechanical interlocking for strong connection while its cellular structure acts as a vibration-damping medium that absorbs solid-borne sound, preventing the harmful sound transmission that occurs through direct rigid-to-rigid contact
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 method effectively absorbs vibrations and shocks, improves the bond strength between plastic elements, and eliminates the need for fastening elements, thus enhancing the product's vibration damping properties and simplifying the production process.
Implementation Method 1
allowing the expandable polymer material to spread at least along the first and/or along the second supporting surface during expansion thereof
Implementation Method 2
The relatively poor elastic properties of many glue layers, however, negatively affect the performances of the assembled plastic product as concerns resistance or even absorption against damage by vibration and/or shock
Data Source
Figure 1a~1b
Figure 1c~1d
Figure 2a~2b
AI summary
Method for manufacturing a product (400) including at least a first (100) and a second (200) hard plastic element. The first and the second element comprise a first (110) and a second (210) supporting surface, respectively, the first and the second supporting surface being substantially complementary to one another.The method comprises at least the steps of (a) applying an expandable polymer material (300) in an unset state to the first supporting surface, (b) bringing the expandable polymer material in contact with the second supporting surface while the expandable polymer material is in an unset state, (c) putting the two supporting surfaces in a first predefined position with respect to each other and locking the first and locking them therein, (d) allowing the expandable polymer material to spread at least along the first and/or second supporting surface during expansion thereof, and (e) allowing the expandable polymer material to set in an expanded state.