Gearless Rotating Shaft Module for Compact Foldable Hinges

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Solution Overview

Problem

Existing screen-foldable cell phones with synchronous transmission mechanisms using gears occupy excessive space due to the large number of gears required, leading to increased thickness.

Innovation Solution

A rotating shaft module comprising a mounting housing with two rotating shafts, an elastic assembly, and a connecting member, which allows for stable sliding and folding without the need for gears, thereby reducing space requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a synchronous transmission mechanism using gears is designed, then the transmission function is achieved, but the space occupied increases and the thickness becomes larger

Engineering Contradiction:

Improvetransmission functionVSAvoidspace occupied

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent replaces the traditional gear-based mechanical synchronous transmission system with a rotating shaft module that uses elastic assemblies (springs) and sliding mechanisms. This substitution eliminates the need for multiple gears while achieving the same synchronous transmission function, directly resolving the contradiction between transmission reliability and space occupation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the fundamental operating parameters of the transmission mechanism by transitioning from gear meshing (rotational contact) to elastic deformation and sliding (linear contact with elastic recovery). This parameter change enables the same transmission function with significantly reduced spatial requirements and thickness.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If a synchronous transmission mechanism using gears is designed, then the transmission function is achieved, but the thickness increases

Engineering Contradiction:

Improvetransmission functionVSAvoidthickness

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

The patent replaces the gear-based mechanical system with a rotating shaft module using elastic assemblies and sliding mechanisms, which achieves synchronous transmission with significantly reduced thickness by eliminating the need for multiple gear stages and their associated spacing requirements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The rotating shaft module employs a nested structure where elastic assemblies are sleeved on rotating shafts, and components are arranged concentrically and in layers, maximizing space utilization and minimizing the overall thickness of the transmission mechanism while maintaining functional integrity.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Reliability

If the number of gears is increased, then the synchronous transmission is achieved, but the device complexity increases

Engineering Contradiction:

Improvesynchronous transmissionVSAvoidnumber of gears

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent substitutes the complex multi-gear system with a simplified rotating shaft module that uses elastic assemblies and sliding mechanisms, reducing the number of discrete components while maintaining synchronous transmission functionality, thereby directly addressing the contradiction between transmission reliability and device complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The rotating shaft module serves multiple functions simultaneously: the elastic assemblies provide both the driving force and the positioning mechanism, while the sliding mechanism enables both motion transmission and adjustment, eliminating the need for separate gears for each function and reducing overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 rotating shaft module enables compact folding mechanisms in electronic devices by eliminating the need for gears, allowing for a more compact design while maintaining stability and functionality.

Implementation Method 1

an elastic assembly, sleeved on each of the two rotating shafts, abutting against the mounting housing, and configured to apply a force to each of the two rotating shafts

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentEP4447025B1Rotating shaft module, folding assembly, and electronic apparatus

Publication Date: 2025.09.17 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD

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AI summary

The present application relates to the technical field of smart devices. A rotating shaft module (50) is provided, which includes a supporting bracket (40); a supporting member (82), arranged opposite to the supporting bracket (40) and slidably connected to the supporting bracket (40), to slide toward a side away from or close to the supporting bracket (40); two rotating shafts (911, 921), rotatably connected to the supporting bracket (40), respectively; where the two rotating shafts (911, 921) rotate simultaneously, one of the two rotating shafts (911, 921) rotates in a first direction and the other rotates in a second direction, the first direction is opposite to the second direction; and an elastic assembly, mounted on the two rotating shafts (911, 921), and configured to adjust a distance between the supporting bracket (40) and the supporting member (82) responsive to that the two rotating shafts (911, 921) rotate simultaneously.