Rotating Shaft Mechanism With Length Control for Foldable Displays

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Solution Overview

Problem

Flexible displays in foldable electronic devices are prone to deformation and damage due to uneven pressure or pulling forces during folding, which affects their service life and reliability.

Innovation Solution

A rotating shaft mechanism with a length maintaining mechanism and main shaft assembly, featuring swing arms, sliding blocks, and connecting assemblies, that adjust the distance between components to stabilize movement and prevent deformation of the flexible display.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the flexible display is folded to enable portability, then the electronic device becomes more compact and portable, but the flexible display is subjected to uneven pressure or pulling force which may cause deformation or damage

Engineering Contradiction:
ImproveportabilityVSAvoidflexible display integrity
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

A length maintaining mechanism is introduced as an intermediary component between the flexible display and the housing. This mechanism includes a first swing arm rotatably connected to the housing and a second swing arm rotatably connected to the flexible display, with a connecting assembly linking the two swing arms. During folding, this intermediary mechanism maintains proper spacing and prevents direct transmission of uneven forces to the flexible display, thereby protecting it while enabling portability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Area of stationary object

If the flexible display is made larger to provide more functions, then the display area increases, but the overall structure of the electronic device becomes larger and less compact

Engineering Contradiction:
Improvedisplay areaVSAvoidoverall structure size
Core Design Contradiction:
Area of stationary objectVSVolume of moving object

Solution Approach 1:

The patent employs dynamic swing arms that can rotate and adjust their positions during folding and unfolding. The first swing arm rotates relative to the housing, and the second swing arm rotates relative to the flexible display, allowing the mechanism to adapt its configuration. This dynamic adjustment enables the mechanism to maintain proper spacing while accommodating the flexible display in a compact state during folding, effectively managing the trade-off between display area and overall structure size.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the length maintaining mechanism uses swing arms and connecting assemblies, then the flexible display is protected from deformation, but the device complexity increases

Engineering Contradiction:
Improveflexible display protectionVSAvoidmechanism structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The length maintaining mechanism is segmented into distinct functional components: a first swing arm connected to the housing, a second swing arm connected to the flexible display, and a connecting assembly linking the two swing arms. This segmentation allows each component to perform its specific function independently while working together as a system. The modular structure makes the complex mechanism more manageable and easier to implement while maintaining effective protection of the flexible display.

Inventive Principle:
Principle #1Segmentation

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 mechanism enhances the stability and reliability of the flexible display by maintaining proper spacing during folding, preventing damage and extending its service life.

Implementation Method 1

The swing rod may be provided with a protrusion, and the sliding slot may be provided with a sliding rail. The protrusion may be accommodated in the corresponding sliding slot, and may slide in the corresponding sliding slot

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

Each swing arm may include a sliding block, a swing rod, and a connecting assembly. The sliding block may be used as a base of the swing arm, and may be configured to be fixedly connected to a housing of the electronic device. An end that is of the swing rod and that is away from the fastening member may be rotatably connected to the fastening member.

Methodology Applied
Scientific EffectMechanical Advantage: Mechanical Advantage

Data Source

PatentEP4390158B1Rotating shaft mechanism and electronic device
Publication Date: 2025.11.05 HUAWEI TECH CO LTD
  • EP4390158B1 patent drawingFigure 1A
  • EP4390158B1 patent drawingFigure 1B~2A
  • EP4390158B1 patent drawingFigure 2B~3

AI summary

A rotating shaft mechanism and an electronic device are provided. The rotating shaft mechanism (1) includes a length maintaining mechanism (1a) and a main shaft assembly (1b). The length maintaining mechanism (1a) includes a fastening member (101) and two swing arms (102, 103), and the two swing arms (102, 103) are rotatably connected to the fastening member (101). The swing arm includes a sliding block (1021), a swing rod (1022), and a connecting assembly (1023), and the swing rod (1022) may slide along the sliding block (1021). The swing rod (1022) is rotatably connected to the fastening member (101), and the connecting assembly (1023) is also rotatably connected to the fastening member (101). When the swing rod (1022) rotates relative to the fastening member (101), the connecting assembly (1023) may be driven to rotate around the fastening member (101). The main shaft assembly (1b) includes a cover plate (105). The length maintaining mechanism (1a) is accommodated in an accommodating groove (1041) of a housing (104). The cover plate (105) includes a main shaft fastening plate (1051) and two support plates (1052, 1053). The main shaft fastening plate (1051) is fastened to the housing (104), the two support plates (1052, 1053) are respectively disposed on two sides of the main shaft fastening plate (1051), and the support plate may cover the swing arm. The support plate is rotatably connected to the connecting assembly (1023), and the support plate may be further rotatably connected to the sliding block (1021). When the connecting assembly (1023) rotates relative to the fastening member (101), the support plate is driven to move, and the sliding block (1021) and the swing rod (1022) are driven to slide relative to each other, so that a distance between the sliding block (1021) and the fastening member (101) is adjusted.