Hollow Ball Stud with Polymeric Core for Mirror Impact Resistance
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Solution Overview
Problem
Existing interior rearview mirror assemblies face challenges in passing impact testing due to the brittleness of metallic ball studs, which can lead to failure and separation of components during ECE 46 and Article 44 testing.
Innovation Solution
A hollow metallic ball stud with a molded plastic core is used, where the plastic fills the cavity of the ball stud, providing additional strength and retention even if the metallic neck region fractures, allowing the assembly to pass impact testing by acting as a tether to hold the mirror components together.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If a solid metallic ball stud is used, then the structure provides sufficient strength, but it uses more metal material and increases cost
Solution Approach 1:
The patent applies composite materials by combining metallic ball stud material with a polymeric core insert. The polymeric material is injected into the hollow cavity of the metallic ball stud during the molding process, creating a composite structure where the polymer reinforces the metallic structure. This composite construction provides sufficient strength to pass impact testing while reducing overall metal material usage and cost.
2Loss of substance
If the metallic ball stud neck region is made thinner to reduce material, then material usage decreases, but the ball stud becomes brittle and may fracture during impact testing
Solution Approach 1:
The patent uses composite materials by injecting polymeric material into the hollow cavity of the metallic ball stud. This composite structure provides reinforcement to the thinner neck region, allowing it to withstand impact forces without fracturing. The polymer acts as a reinforcing element that compensates for the reduced metallic material in critical areas.
Solution Approach 2:
The patent applies beforehand cushioning by incorporating a polymeric core insert into the hollow cavity of the metallic ball stud before final assembly. This polymeric material serves as a pre-installed cushioning element that absorbs and distributes impact forces, preventing catastrophic failure of the thinner neck region during impact testing.
3Loss of substance
If a hollow ball stud is used, then material usage and cost decrease, but the ball stud lacks sufficient structural integrity to retain components during impact testing
Solution Approach 1:
The patent applies composite materials by combining the hollow metallic ball stud structure with an injected polymeric core. The polymeric material fills the hollow cavity and creates a composite structure that provides the necessary structural integrity and component retention capability during impact testing, while the hollow metallic structure reduces overall material usage.
Solution Approach 2:
The patent applies the nested doll principle by placing the polymeric core insert inside the hollow cavity of the metallic ball stud. This nested configuration allows the polymer to reinforce the metallic structure from within, providing structural integrity while maintaining the material reduction benefits of the hollow design.
4Reliability
If plastic molding material is injected into the hollow ball stud, then component retention improves, but the manufacturing process complexity increases
Solution Approach 1:
The patent applies merging by combining the ball stud manufacturing process with the polymeric core injection process into a single integrated operation. The hollow metallic ball stud serves as the mold cavity for injecting the polymeric material, eliminating the need for separate manufacturing and assembly steps. This merged process improves component retention while managing manufacturing complexity through process integration.
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 enables the interior rearview mirror assembly to withstand impact testing by absorbing energy and maintaining structural integrity, reducing material usage and costs while ensuring compliance with regulatory standards.
Implementation Method 1
The mirror mounting portion or toggle element is overmolded at the base of the ball stud and the plastic molding material is molded into the hollowed portion or passageway of the ball stud
Implementation Method 2
The solution enables the interior rearview mirror assembly to withstand impact testing by absorbing energy and maintaining structural integrity
Data Source
AI summary
An interior rearview mirror assembly for a vehicle includes a mounting structure configured to attach at an interior portion of the vehicle and a mirror head pivotally mounted at the mounting structure. The mirror head includes a mirror reflective element and a ball stud that pivotally mounts the mirror head at a socket element of the mounting structure. The ball stud is a metallic element having a base portion and a neck region that extends from the base portion, with a ball member at an end of the neck region distal from the base portion. The ball stud includes a passageway formed at least through the base portion and the neck region. A mounting portion is molded at least partially around the base portion to attach the ball stud at the mirror head. The passageway of the ball stud is at least partially filled with a polymeric material.