Terminal Side Key Waterproofing via Interference-Fitted Sealing Ring

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Solution Overview

Problem

Existing waterproof designs for mobile phone side keys face challenges in balancing cost, waterproof performance, and miniaturization, with current methods being complex, costly, or not suitable for mass production.

Innovation Solution

A waterproof apparatus for a terminal side key that integrates a silica gel waterproof ring and an arched metal film or flexible printed circuit board with the side-key circuit board, assembled within a terminal shell using injection molding and interference fitting, providing a compact and reliable waterproof solution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the waterproof plug is made by molding flexible glue, steel disc and plastic glue into one body, then waterproof function is achieved, but the process becomes complicated and molding cost increases

Engineering Contradiction:
Improvewaterproof functionVSAvoidprocess complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The waterproof structure is divided into separate components: the waterproof plug (with steel disc and flexible glue) and the adhesive layer are distinct elements that can be manufactured and assembled separately, simplifying the overall process while maintaining waterproof functionality

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The steel disc is extracted as a separate functional component from the molded assembly, allowing it to be independently manufactured and then integrated into the waterproof plug, reducing the complexity of molding multi-material components

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If double-shot molding technology is used to inject side key and plastic glue together, then waterproofing is achieved, but material selection and appearance processing are limited

Engineering Contradiction:
ImprovewaterproofingVSAvoidmaterial selection flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The side key assembly is segmented into the key body, adhesive layer, and waterproof seal as separate components, allowing each to be manufactured from optimal materials independently and assembled together, thereby expanding material selection flexibility while maintaining waterproof integrity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The design utilizes composite construction with the adhesive layer made from flexible glue and the waterproof seal from appropriate sealing materials, allowing selection of materials based on their specific properties rather than being constrained by single-shot or double-shot molding material compatibility

Inventive Principle:
Principle #40Composite materials

3Adaptability or versatility

If independent key scheme is used for waterproofing, then replace ability and appearance processing are improved, but design space requirement increases

Engineering Contradiction:
Improvereplace abilityVSAvoiddesign space
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The independent key is nested within a compact waterproof assembly where the key body, adhesive layer, and waterproof seal are tightly integrated in a layered configuration, reducing the overall design space required while maintaining the ability to replace the key independently

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The adhesive layer is implemented as a thin flexible film that provides both bonding and waterproofing functions, minimizing the thickness and volume of the waterproof assembly while maintaining structural integrity and replaceability of the key component

Inventive Principle:
Principle #30Flexible shells and thin films

4Ease of operation

If flexible glue is used as side key material, then deformation space is provided, but rigidity affects hand feeling and maintenance cost increases

Engineering Contradiction:
Improvedeformation capabilityVSAvoidmaintenance cost
Core Design Contradiction:
Ease of operationVSEase of repair

Solution Approach 1:

The side key system is segmented into the flexible adhesive layer (providing deformation capability) and the rigid key body (providing structural integrity and hand feeling). When maintenance is needed, only the key body needs to be replaced, not the entire adhesive structure, significantly reducing maintenance costs

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different parts of the side key assembly have different material properties optimized for their specific functions: the adhesive layer is made flexible for deformation and bonding, while the key body is made rigid for structural strength and tactile feedback, with each part replaceable according to its wear or damage patterns

Inventive Principle:
Principle #3Local quality

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 solution achieves high-grade waterproofing with reduced costs and simplified assembly, aligning with the trend of miniaturization while maintaining reliable performance and appearance processing capabilities.

Implementation Method 1

the circuit board waterproof ring (21) wrapping the side-key circuit board (23) and the arched metal film (22) as a whole is combined with a sidewall of the terminal shell (1) in an interference-fitted manner

Methodology Applied
Scientific EffectInterference fit:

Implementation Method 2

an arched metal film (22) fixedly connected to the side-key circuit board

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3147922B1Waterproof apparatus for terminal side-key, and terminal
Publication Date: 2018.05.30 ZTE CORP
  • EP3147922B1 patent drawingFigure 1
  • EP3147922B1 patent drawingFigure 2
  • EP3147922B1 patent drawingFigure 3~4

AI summary

A waterproof apparatus for a terminal side key and a terminal are disclosed. The apparatus includes: a terminal shell (1) with a sidewall hole that is filled with a terminal side key (3), and a terminal side-key circuit board component (2) connected to a terminal mainboard (4), herein, the terminal side-key circuit board component (2) includes: a side-key circuit board (23), an arched metal film (22) fixedly connected to the side-key circuit board, and a circuit board waterproof ring (21) used for wrapping the side-key circuit board (23) and the arched metal film (22) as a whole, herein, the circuit board waterproof ring (21) wrapping the side-key circuit board (23) and the arched metal film (22) as a whole is combined with a sidewall of the terminal shell (1) in an interference-fitted manner. The waterproof apparatus for the terminal side key and the terminal have low costs and high waterproof grades and are simplified in assembly.