Foldable Hinge Structure With Variable-Thickness Shafts for Quiet Motion
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Solution Overview
Problem
Foldable electronic devices often generate abnormal noises due to the hinge structure and are typically thick, lacking a slim and natural hinge motion, which affects portability and user experience.
Innovation Solution
A hinge structure with reduced noise and a slimmer design, featuring rotary supports, arm parts with cam structures, and rotary shafts of varying thicknesses to enhance force transmission and balance, allowing for stable mounting angles and improved manufacturing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hinge structures are used in foldable electronic devices, then the device can achieve foldable functionality, but abnormal noises are generated during hinge motion
Solution Approach 1:
The rotary shaft is designed with non-uniform thickness, featuring a first thickness in the first portion and a second thickness in the second portion. This local variation in dimensional quality allows different sections of the rotary shaft to serve different functions: the thicker portion provides structural strength and stability, while the thinner portion reduces mass and moment of inertia, enabling smoother rotation and reducing noise generation during hinge motion.
2Reliability
If conventional hinge structures are used, then foldable functionality is achieved, but the device becomes thick and loses portability
Solution Approach 1:
The hinge structure is divided into multiple functional components: rotary supports, arm parts with cam structures, and rotary shafts with varying thicknesses. This segmentation allows each component to be optimized independently for its specific function, enabling the overall structure to achieve the required stability with reduced total volume and thickness, thereby improving portability.
Solution Approach 2:
The rotary shaft employs non-uniform thickness distribution, with a first thickness in the first portion and a second thickness in the second portion. This local quality variation allows the structure to maintain necessary strength and stability in critical areas while minimizing material usage and overall thickness in non-critical areas, achieving a balance between structural integrity and device slimness.
3Length of stationary object
If the hinge structure is made slimmer, then portability is improved, but manufacturing precision and dimensional accuracy may be compromised
Solution Approach 1:
The rotary shaft is designed with specific thickness variations: a first thickness in the first portion and a second thickness in the second portion. These precisely controlled local dimensional variations are optimized to provide sufficient structural strength and stability while maintaining a slim overall profile. The specific thickness values are engineered to ensure manufacturability and dimensional accuracy within standard manufacturing tolerances.
4Force
If the hinge structure uses varying thickness rotary shafts, then force transmission and balance are improved, but structural complexity increases
Solution Approach 1:
The rotary shaft features a first thickness in the first portion and a second thickness in the second portion, creating local quality variations that optimize force transmission. The thicker portion provides greater structural strength for areas requiring higher load-bearing capacity, while the thinner portion reduces mass and moment of inertia for smoother rotation. This approach achieves improved force balance and transmission without introducing complex mechanisms, maintaining relative structural simplicity.
Data Source
AI summary
The disclosure discloses a foldable electronic device including rotary supports connected to housings, arm parts connected to the rotary supports, and rotary shafts disposed in the arm parts. At least one arm part among the arm parts includes arm cam structures in which fastening holes spaced apart from each other by a predetermined gap are formed. A shape of a cross-section of a rotary shaft inserted into the fastening holes includes flat areas and curved areas when viewed in an axial direction in which the rotary shaft is inserted. The rotary shaft is formed such that a first thickness of a first portion at least partially disposed in one fastening hole among the fastening holes differs from a second thickness of a second portion at least partially disposed in another fastening hole among the fastening holes.