Foldable Hinge Force Transmission for Detent and Durability

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Solution Overview

Problem

The existing hinges in foldable electronic devices face challenges in implementing a free stop and detent function while maintaining a small size, as the increased stress from folding and unfolding operations can lead to damage.

Innovation Solution

The implementation of a force transmission member that changes the direction of the hinge actuator's force to the pressing surface, allowing the member to transmit a frictional force and detent torque to the rotation guide of the hinge leaf, thereby enabling a free stop and detent function.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the sizes of the friction element and cam are reduced to reduce the size of the foldable electronic device, then the device size is reduced, but the stress applied to these components increases leading to potential damage

Engineering Contradiction:
Improvehinge sizeVSAvoidcomponent durability
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

A force transmission member is introduced as an intermediary component between the cam and the friction element. This member transmits the force generated by the cam to the friction element, enabling the free stop and detent functions without requiring the friction element and cam to be in direct contact. This intermediary mechanism allows for reduced component sizes while maintaining structural integrity and durability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The traditional direct mechanical contact system between the cam and friction element is replaced with a force transmission member that transfers force through a different mechanical pathway. This substitution allows for optimized force distribution, reducing the stress concentration on individual components while maintaining the necessary functional performance for free stop and detent operations.

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

2Reliability

If a free stop and detent function is implemented using traditional friction elements and cam structures, then the functional requirements are met, but the hinge size increases

Engineering Contradiction:
Improvefree stop and detent functionVSAvoidhinge size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The hinge mechanism is segmented into distinct functional components: the cam structure, the force transmission member, and the friction element. This segmentation allows each component to be optimized independently for its specific function, enabling the overall hinge size to be reduced while maintaining the free stop and detent functions. The force transmission member specifically bridges the cam and friction element, allowing compact integration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The force transmission member is integrated within the existing hinge structure, nesting the force transmission function within the compact hinge assembly. This nested configuration allows the force transmission member to occupy space efficiently within the hinge, enabling the free stop and detent functions without proportionally increasing the overall hinge volume.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Strength

If larger friction elements and cam structures are used to reduce stress, then component durability is improved, but the device becomes less portable

Engineering Contradiction:
Improvecomponent durabilityVSAvoiddevice portability
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The force transmission member acts as a mediator that enables durable force transmission without requiring oversized friction elements or cam structures. By introducing this intermediary component, the system achieves component durability through optimized force distribution rather than through increased component size and weight, thereby maintaining device portability.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 effectively reduces the risk of damage to the hinge during folding and unfolding operations while maintaining a compact size and improving user convenience by providing tactile feedback at specific angles.

Implementation Method 1

the force transmission member transmits a frictional force and detent torque to a rotation guide of a hinge leaf

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the force transmission member transmits frictional force and detent torque to a rotation guide of a hinge leaf

Methodology Applied
Scientific EffectTorque: Torque

Data Source

PatentEP4239989B1Hinge and foldable electronic device including same
Publication Date: 2025.03.19 SAMSUNG ELECTRONICS CO LTD
  • EP4239989B1 patent drawingFigure 1
  • EP4239989B1 patent drawingFigure 2A
  • EP4239989B1 patent drawingFigure 2B

AI summary

Disclosed is a foldable electronic device including a hinge. A foldable electronic device according to various embodiments of the disclosure may include a foldable enclosure which includes multiple sub-enclosures and is folded and unfolded, a hinge configured to rotatably connect the multiple sub-enclosures around at least one rotation axis, wherein the hinge may include multiple hinge leaves respectively coupled to ends of the multiple sub-enclosures and configured to rotate during folding and unfolding operations of the foldable enclosure, a rotation guide which is formed on each of the hinge leaves and includes a rotation surface having a curved-surface of a shape corresponding to a rotation trajectory of the hinge leaves, a force transmission member having a pressing surface pressed against the rotation surface of the rotation guide, a force diverting part configured to change the direction of a force applied in a direction having a directional component parallel to the pressing surface to a direction having a directional component perpendicular to the pressing surface, so as to press the force transmission member against the curved-surface of the rotation guide, and a hinge actuator configured to apply a force to the force diverting part in a direction having a directional component parallel to the pressing surface.