Vehicle Back Door Adhesive Frame for Liquid Ingress Control
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Solution Overview
Problem
Vehicle back doors with inner and resin outer panels adhered using adhesives of different elasticities face challenges in preventing liquid ingress into the vehicle interior when open, due to gaps and uneven adhesive application.
Innovation Solution
A vehicle back door design utilizing a first adhesive with high strength and low elasticity for structural areas and a second adhesive with higher elasticity for design-facing areas, forming a frame shape with extension portions that restrict liquid flow when the door is open, guiding liquid away from the vehicle interior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a first adhesive with high adhesive strength and low elasticity is used to join the inner panel and resin outer panel, then adhesive strength is improved, but heat strain occurs in the resin outer panel
Solution Approach 1:
The patent applies different adhesives with different elasticities to different regions of the outer panel. The first adhesive with low elasticity is used in non-design face regions where high strength is needed, while the second adhesive with high elasticity is used in design face regions to prevent heat strain. This local differentiation resolves the contradiction by matching adhesive properties to regional requirements.
2Object-affected harmful factors
If a second adhesive with higher elasticity than the first adhesive is used to suppress heat strain, then heat strain is reduced, but adhesive strength between the inner panel and resin outer panel is lowered
Solution Approach 1:
The patent divides the bonding region into two zones: design face regions where the second adhesive with high elasticity is applied to suppress heat strain, and non-design face regions where the first adhesive with high strength is applied to ensure bonding strength. This spatial separation allows both adhesive strength and heat strain suppression to be achieved simultaneously in their respective regions.
3Strength
If the first adhesive and second adhesive with different elasticities are applied to different locations, then adhesive strength and heat strain suppression are both addressed, but gaps occur between the adhesives and liquid can enter the vehicle interior
Solution Approach 1:
The patent designs the first and second adhesives to form a continuous frame-shaped bonding region where the adhesives meet and connect. This continuous structure eliminates gaps between the different adhesive types, preventing liquid from penetrating through the adhesive interface into the vehicle interior, while maintaining both high strength and heat strain suppression properties.
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
Effectively suppresses liquid entry into the vehicle interior by redirecting and restricting liquid flow through the strategic arrangement of adhesive extensions, ensuring the vehicle remains dry even when the door is open.
Implementation Method 1
an inner panel and a resin outer panel are adhered together using a urethane-based adhesive
Implementation Method 2
the flow of liquid from the space enclosed by the first adhesive and the second adhesive toward the outer side (vehicle inner side) is restricted
Implementation Method 3
liquid such as rainwater has entered and collected between the inner panel and the outer panel
Data Source
AI summary
A vehicle back door including: an inner panel; an outer panel that has an attached member attached to a vehicle outer portion of the outer panel; a first adhesive that has at least a part arranged in a region overlapping the attached member as viewed from a vehicle rear side, and that joins the inner panel and the outer panel together; and a second adhesive that has a higher elasticity than the first adhesive, that has at least a part arranged in a region overlapping locations of the outer panel excluding a location where the attached member is attached as viewed from the vehicle rear side, that forms a frame shape together with the first adhesive, and that joins the inner panel and the outer panel together.