Automotive Door Protector Sealing via Injection Molding
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Solution Overview
Problem
Existing protectors with sensors for automobile opening and closing panels face issues with uneven product shapes, operability, and insufficient sealing due to the use of adhesives and complex processes, which can lead to water leaks and sensor malfunction.
Innovation Solution
The solution involves an extrusion molded protector with a rubber-like elastic body and a non-conductive insert, where a primary and secondary sealing layer are formed through injection molding to cover wire connection parts, preventing contact and ensuring stable sealing without the need for adhesives or extra parts, thus improving shape uniformity and sensor functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive is used to seal wire connection parts, then sealing function is improved, but manufacturing complexity and time increase due to curing requirements
Solution Approach 1:
The patent replaces the chemical bonding system (adhesive curing) with a mechanical molding system (injection molding). The sealing layer is formed through injection molding that mechanically encapsulates wire connection parts, eliminating the need for adhesive application and curing processes. This substitution transforms the sealing mechanism from chemical to mechanical, resolving the contradiction between sealing reliability and manufacturing complexity.
Solution Approach 2:
The patent changes the state and properties of the sealing material from liquid adhesive to molten plastic that solidifies through cooling. By changing the physical state and bonding mechanism parameters, the sealing process transitions from requiring chemical curing time to a controlled molding process with predictable cycle times, reducing manufacturing complexity while maintaining sealing reliability.
2Reliability
If adhesive is used for sealing, then sealing function is improved, but production time increases due to curing time
Solution Approach 1:
The patent replaces the time-dependent chemical curing process with a mechanical injection molding process. The sealing layer is formed by injecting molten material that solidifies through cooling within a controlled mold, eliminating the unpredictable curing time associated with adhesives. This mechanical approach standardizes production time and eliminates the waiting period, thereby improving productivity while maintaining sealing reliability.
Solution Approach 2:
The patent performs preliminary preparation of the molding cavity and material injection before the actual sealing is needed. The injection molding process prepares the sealing layer in advance during the molding cycle, so that by the time the product is completed, the sealing is already in place without requiring additional curing time. This preliminary action integrates sealing into the main production flow, reducing overall production time.
3Reliability
If complex sealing processes are used, then sealing reliability is improved, but product shape uniformity deteriorates
Solution Approach 1:
The patent integrates multiple functions into the injection molding process: the molding cavity simultaneously forms the product shape and creates the sealing layer, while also positioning and encapsulating wire connection parts. This multi-functional approach eliminates the need for separate sealing operations that could compromise shape uniformity, achieving both sealing reliability and manufacturing precision through a single unified process.
Solution Approach 2:
The patent controls and standardizes the parameters of the injection molding process (temperature, pressure, injection rate, cooling time) to ensure consistent sealing quality and uniform product shape. By precisely controlling these parameters, the process achieves reliable sealing without the variability introduced by manual adhesive application or complex multi-step sealing procedures, thereby maintaining manufacturing precision.
4Reliability
If extra parts and processes are used for sealing, then sealing function is improved, but device complexity increases
Solution Approach 1:
The patent merges the sealing function with the main product structure by integrating the sealing layer formation into the injection molding process. Instead of using separate adhesive applications or additional sealing components, the sealing layer is molded as an integral part of the product housing, encapsulating wire connection parts within the same manufacturing cycle. This merging eliminates extra parts and simplifies the overall device structure while maintaining sealing reliability.
Solution Approach 2:
The injection molding process serves multiple functions simultaneously: it forms the product housing, creates the sealing layer, positions wire connection parts, and provides structural support. This multi-functional approach consolidates what would otherwise require multiple separate components and processes into a single integrated system, reducing device complexity while ensuring sealing reliability through the unified design.
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 enhances the operability and sealing efficiency of the protector's terminal parts, reducing the risk of water leaks and sensor malfunction, while simplifying the manufacturing process and reducing costs by eliminating the need for adhesive curing time and extra components.
Implementation Method 1
the rubber like elastic bodies 34, 35 contact with each other and the two core wires 31, 32 short
Implementation Method 2
rubber like elastic bodies 34, 35 having conductivity with a space 33 therebetween
Implementation Method 3
a primary sealing layer 100 and a secondary sealing layer 200 formed thereon by means of injection molding
Implementation Method 4
injection molding to cover wire connection parts
Data Source
AI summary
A protector with a sensor is installed on a sliding door for detecting an object by touch between two core wires in a hollow part. In a terminal part of the protector with the sensor, the core wires drawn out are connected with legs of a resistor. A primary seal is formed by grinding a surface of the hollow part of the terminal part of an extrusion molded part, positioning a ground part on a die and covering wire connection parts and a side of another end of an insert while also covering the ground part by means of injection molding. A secondary seal is formed by means of the injection molding for coating a part formed with the primary seal for forming an external shape of a product.