SMA-Damped Foldable Rotation Mechanism With Synchronized Swing Arms

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Solution Overview

Problem

Conventional rotating mechanisms for foldable electronic devices require numerous parts, leading to increased assembly complexity, cost, and inconsistency, while existing solutions for improving damping hand feeling often necessitate complex configurations and additional components.

Innovation Solution

A rotating mechanism utilizing a damping member made of shape memory alloy (SMA) with synchronization swing arms that generate damping force through deformation, reducing the need for additional parts and simplifying assembly, and providing damping hand feeling without complex configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional rotating mechanisms use mechanical springs to provide damping force, then damping hand feeling is improved, but the quantity of parts increases and the rotating structures become complex

Engineering Contradiction:
Improvedamping hand feelingVSAvoidrotating structure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces the conventional mechanical spring-based damping system with a shape memory alloy (SMA) damping body that provides damping force through material deformation. This substitution eliminates the need for separate spring components and their associated mounting structures, thereby reducing part quantity and simplifying the rotating mechanism structure while maintaining the damping hand feeling during rotation operations.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes the temperature-dependent phase transformation properties of shape memory alloy to change the mechanical parameters of the damping body. By controlling the phase transformation temperature and alloy composition, the damping characteristics can be optimized to provide appropriate damping hand feeling without requiring complex mechanical adjustments or additional components.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If conventional rotating mechanisms increase quantities of parts to achieve specific damping hand feeling, then damping performance is improved, but assembly difficulty and fitting difficulty increase

Engineering Contradiction:
Improvedamping hand feelingVSAvoidassembly difficulty
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The patent merges the damping function into a single integrated damping body made of shape memory alloy, combining what were previously separate components (springs, dampers, mounting brackets) into one element. This integration dramatically reduces the number of parts that need to be assembled and fitted, making the manufacturing process simpler and more consistent while maintaining the required damping hand feeling.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The shape memory alloy damping body provides self-regulating damping characteristics through its inherent material properties. The alloy automatically adjusts its stiffness and damping force based on deformation magnitude and rate, eliminating the need for complex mechanical adjustment mechanisms or multiple components with precise fitting requirements. This self-service capability simplifies assembly while ensuring consistent damping performance.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If conventional rotating mechanisms use numerous parts to provide damping force, then damping functionality is achieved, but product costs increase

Engineering Contradiction:
Improvedamping hand feelingVSAvoidnumber of parts
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts the damping function from the complex assembly of mechanical springs and dampers and consolidates it into a single shape memory alloy damping body. This extraction eliminates unnecessary intermediate components and their associated costs, reducing the overall part count while maintaining the essential damping hand feeling functionality that users expect during rotation operations.

Inventive Principle:
Principle #2Taking out (Extraction)

4Ease of operation

If conventional rotating mechanisms increase quantities of parts to achieve specific damping hand feeling, then damping performance is improved, but product consistency is affected

Engineering Contradiction:
Improvedamping hand feelingVSAvoidproduct consistency
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The shape memory alloy damping body provides self-regulating damping characteristics through its inherent material properties. The alloy automatically adjusts its stiffness and damping force based on deformation magnitude and rate, eliminating the need for complex mechanical adjustment mechanisms or multiple components with precise fitting requirements. This self-service capability simplifies assembly while ensuring consistent damping performance.

Inventive Principle:
Principle #25Self-service

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 simplifies assembly, reduces costs, and enhances damping hand feeling by using SMA-based damping members, ensuring smooth operation and stability in foldable electronic devices.

Implementation Method 1

the damping body is made of a shape memory alloy. When the first synchronization swing arm and the second synchronization swing arm are in a folded state, the damping body is in a first state, where the first state is an initial state of the damping body. The first synchronization swing arm is rotated relative to the fastening base to drive one end of the damping body to rotate, the first synchronization swing arm and the second synchronization swing arm are relatively unfolded from the folded state, and the damping body is in a second state, where the second state is that the damping body is deformed and generates damping force relative to the first synchronization swing arm.

Methodology Applied
Scientific EffectShape memory alloy deformation: Shape Memory Alloy

Data Source

PatentEP4403785B1Rotating mechanism and foldable electronic device
Publication Date: 2025.09.10 HONOR DEVICE CO LTD
  • EP4403785B1 patent drawingFigure 1
  • EP4403785B1 patent drawingFigure 2~3
  • EP4403785B1 patent drawingFigure 4~5

AI summary

This application provides a rotating mechanism and a foldable electronic device. The rotating mechanism includes a fastening base, a first synchronization swing arm, a second synchronization swing arm, and a damping member. The first synchronization swing arm and the second synchronization swing arm are respectively mounted on two opposite sides of the fastening base in a width direction and are rotatably connected to the fastening base. The damping member includes a baffle plate and a damping body, the damping body is connected between the first synchronization swing arm and the baffle plate, two opposite ends of the damping body are disposed along a length direction of the fastening base, and the damping body is made of a shape memory alloy. When the first synchronization swing arm and the second synchronization swing arm are in a folded state, the damping body is in a first state, where the first state is an initial state of the damping body. The first synchronization swing arm is rotated relative to the fastening base to drive one end of the damping body to rotate, the first synchronization swing arm and the second synchronization swing arm are relatively unfolded from the folded state, and the damping body is in a second state, where the second state is that the damping body is deformed and generates damping force relative to the first synchronization swing arm.