Spiral-Groove Synchronization Mechanism for Compact Foldable Hinges

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Solution Overview

Problem

Existing synchronization mechanisms for foldable screens are bulky, costly, and difficult to assemble due to the complexity of gear arrangements and high part counts, which makes it challenging to achieve synchronous rotation while minimizing size and weight.

Innovation Solution

A synchronization mechanism featuring a base, a slider, and swing arms that utilize a sliding constraint system with spiral grooves and protrusions to achieve synchronous rotation, reducing the number of parts and simplifying assembly while maintaining stable and reliable transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If four gears are successively arranged to ensure synchronous rotation, then the synchronous transmission reliability is improved, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improvesynchronous transmission reliabilityVSAvoidgear arrangement complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the functions of four separate gears into a single gear structure that directly engages with both swing arms. This unified gear design maintains synchronous transmission reliability while eliminating the complexity of assembling and positioning multiple gears, thereby reducing device complexity and manufacturing cost

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If four pinion gears are assembled and meshed based on positions, then the synchronous rotation of left and right middle frames is achieved, but the assembly difficulty and time increase

Engineering Contradiction:
Improvesynchronous rotation accuracyVSAvoidassembly ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines multiple pinion gears into a single integrated gear component that simultaneously engages with both swing arms. This eliminates the need for precise positioning and assembly of multiple gears, significantly reducing assembly difficulty and time while maintaining synchronous rotation accuracy

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a gear set with four successively meshed gears is used, then the synchronous swing is achieved, but the size of the synchronization mechanism increases

Engineering Contradiction:
Improvesynchronous swing stabilityVSAvoidsynchronization mechanism volume
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent consolidates four successive gears into a single gear structure, dramatically reducing the volume of the synchronization mechanism. This unified design maintains synchronous swing stability through direct engagement with both swing arms while minimizing the space required for the mechanism

Inventive Principle:
Principle #5Merging (Combining)

4Strength

If the size of the gear is not significantly reduced, then the strength of meshing teeth is ensured, but the overall size of the electronic device increases

Engineering Contradiction:
Improvemeshing teeth strengthVSAvoidelectronic device volume
Core Design Contradiction:
StrengthVSVolume of moving object

Solution Approach 1:

The patent uses a single larger gear structure that provides sufficient meshing tooth strength while reducing the overall volume of the synchronization mechanism. This unified gear design ensures adequate strength for reliable operation while minimizing the space required, thereby reducing the overall size of the electronic device

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4269824B1Synchronization mechanism, rotating shaft mechanism and electronic device
Publication Date: 2025.05.07 HONOR DEVICE CO LTD
  • EP4269824B1 patent drawingFigure 1
  • EP4269824B1 patent drawingFigure 2
  • EP4269824B1 patent drawingFigure 3

AI summary

Embodiments of this application provide a synchronization mechanism, a rotating shaft mechanism, and an electronic device. The synchronization mechanism includes a swing arm and a slider, the swing arm rotates around an axis, the slider is slidably disposed in a direction parallel to the axis, a spiral groove is disposed on the swing arm, and a protruding part that fits the spiral groove is disposed on the slider. In embodiments of this application, a rotary swing arm mechanism on which the spiral groove is disposed is used to fit the slider, so that a size of a synchronization mechanism with a requirement for a small size of, for example, a foldable screen is further reduced, a quantity of parts is reduced, synchronous transmission is stable, and a clearance is small.