Compact Hinge Friction Sleeve for Stable Torque Across Temperature

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Solution Overview

Problem

Existing hinge technologies for foldable computing devices face challenges in maintaining consistent torque and friction control across varying temperatures and conditions, which affects the ease of operation and durability of the device.

Innovation Solution

A compact hinge design featuring torque transfer posts and sleeves with expansion slits, where the posts are larger in diameter than the sleeves, allowing for compressive force and friction control, ensuring constant friction force despite temperature changes, and a gear set for synchronized rotation, along with a customizable torque adjustment mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the hinge uses a fixed friction mechanism without expansion slits, then the structure is simpler, but the friction force varies with temperature changes affecting operational consistency

Engineering Contradiction:
Improvefriction force consistencyVSAvoidhinge structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The torque transfer sleeves incorporate expansion slits that allow the sleeves to expand and contract in response to temperature changes. This thermal expansion capability enables the friction interface to maintain consistent friction force across varying temperatures, resolving the contradiction between reliability and structural simplicity.

Inventive Principle:
Principle #37Thermal expansion

Solution Approach 2:

The hinge mechanism transitions from a static friction interface to a dynamic one where the torque transfer sleeves can adjust their dimensions through expansion slits. This dynamic adaptation allows the friction force to remain constant despite temperature variations, improving reliability without excessive complexity.

Inventive Principle:
Principle #15Dynamics

2Force

If the torque transfer posts are larger in diameter than the central bores, then compressive force and friction control are improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvecompressive forceVSAvoiddimensional tolerance
Core Design Contradiction:
ForceVSManufacturing precision

Solution Approach 1:

The design intentionally creates an interference fit condition where torque transfer posts are larger in diameter than the central bores of the sleeves. This parameter change (oversized posts relative to bores) generates the necessary compressive force for friction control, while the expansion slits provide the compliance needed to accommodate manufacturing variations.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the hinge allows for torque adjustment mechanism, then the adaptability to different operational conditions is improved, but the device complexity increases

Engineering Contradiction:
Improvetorque adjustment capabilityVSAvoidhinge mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The hinge incorporates a torque adjustment mechanism that allows the compressive force to be pre-set to different levels. This preliminary action enables the hinge to be configured for specific operational requirements before use, providing adaptability without requiring complex real-time control systems.

Inventive Principle:
Principle #10Preliminary action

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 design provides consistent and adjustable torque control, enhancing the operational ease and durability of foldable computing devices by maintaining friction force and allowing for precise adjustment of hinge torque, thus improving user experience and device longevity.

Implementation Method 1

the first and second torque transfer posts are larger in diameter than the central bores through the first and second torque transfer sleeves causing the first and second torque transfer sleeves to apply compressive force against the respective inserted first and second torque transfer posts

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the first torque transfer sleeve includes a first expansion slit and the second torque transfer sleeve includes a second expansion slit for allowing the torque transfer sleeves to expand and/or contract in response to changing conditions so that the friction force remains constant or approximately constant despite changing temperature or other conditions

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3821317B1Compact hinge for electronic devices
Publication Date: 2024.11.06 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3821317B1 patent drawingFigure 1
  • EP3821317B1 patent drawingFigure 2
  • EP3821317B1 patent drawingFigure 3

AI summary

A compact hinge includes two body attachments, each body attachment having a torque transfer post. A compressive friction sleeve includes a first torque transfer sleeve and a second torque transfer sleeve. A first torque transfer post is inserted into the first torque transfer sleeve and a second torque transfer post is inserted into the second torque transfer sleeve. A gear set causes the first torque transfer post to rotate with the same rotational angle as the second torque transfer post.