Compensation Nut Plastic Overmolding Thread Protection
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Solution Overview
Problem
Existing compensation nuts suffer from thread deterioration of the application attachment bolt due to friction with internal metal legs, preventing re-use and requiring complex designs that increase manufacturing costs and weight.
Innovation Solution
A compensation nut with a plastic overmolded conical section inside the hollow bolt, featuring hooks and indentations to prevent relative movement and axial contraction, along with elastic attachment springs and a dome-shaped base for elasticity, allowing interference-based engagement instead of friction, enabling re-use and simplified manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If internal metal legs are used in the compensation bolt, then threaded engagement is facilitated, but the thread of the application attachment bolt deteriorates due to friction
Solution Approach 1:
A plastic overmolding is introduced as an intermediary material between the application attachment bolt and the compensation bolt. This plastic overmolding is molded directly onto the internal wall of the hollow compensation bolt, replacing the metal legs that caused friction damage. The plastic material provides sufficient grip for threaded engagement while being gentler on the application bolt threads, preventing deterioration and enabling reuse.
2Strength
If internal connection members are formed by legs, then connection is achieved, but the design becomes complex and manufacturing cost increases
Solution Approach 1:
The complex internal metal legs are extracted and replaced by a simpler plastic overmolding solution. Instead of manufacturing separate metal connection members and assembling them, the plastic overmolding is molded directly onto the hollow compensation bolt in one step. This eliminates the need for separate internal connection components while maintaining the necessary connection strength through the plastic material's friction and interference fit.
Solution Approach 2:
The compensation bolt becomes a composite structure combining metal (the hollow compensation bolt itself) and plastic (the overmolding). This composite approach leverages the strength and rigidity of the metal bolt while using the plastic overmolding to provide the connection function, resulting in a simpler overall design compared to using complex metal legs alone.
3Weight of moving object
If the hollow bolt thickness is limited, then weight is reduced, but external zones of the thread must be sacrificed to provide material for internal connection elements
Solution Approach 1:
The plastic overmolding serves as an intermediary that eliminates the need to sacrifice thread material. By molding the plastic directly onto the hollow bolt, the full external thread surface remains available for engagement with the nut, while the plastic provides the necessary internal connection features without requiring material removal or thinning of the bolt wall.
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 provides a lightweight, cost-effective compensation nut that maintains variable distance without damaging the application bolt, allowing multiple installation and removal cycles while withstanding vehicle vibrations and simplifying manufacturing.
Implementation Method 1
the slight shrinkage of said overmolding (9) caused by cooling
Implementation Method 2
these external legs act elastically as a spring, being compressed against the edge of the orifice
Data Source
Figure 1~4
Figure 5~7
AI summary
A compensating nut formed by the assembly of a nut (2) and a bolt (3) and used to attach an application to a surface or panel while maintaining a variable distance between said surface and the supporting element or chassis in which the nut is attached, preventing this distance from collapsing when said application attachment bolt is tightened, that includes a slightly flexible plastic annular body, such as an overmolded sleeve (9) of vulcanized plastic, held tightly in the cylindrical axial internal hollow of said bolt (3).