Virtual-Axis Hinge Structure With Click Torque for Foldables
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Solution Overview
Problem
In foldable electronic devices, the protrusion of a hinge shaft from the inner surface of housings reduces the effective area and limits design options, and existing shaft-less hinges struggle to generate a click at predetermined rotation angles due to their structural limitations.
Innovation Solution
A hinge design that utilizes a virtual rotation axis, incorporating a link mechanism with guide grooves and torque generating mechanisms to ensure rotation symmetry and generate a click with sufficient strength without protruding shafts, allowing for increased inner surface area and design flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shaft is used as a rotation axis in a hinge, then the hinge can provide stable rotation, but the shaft protrudes from the inner surface of the housing, reducing effective area and limiting design
Solution Approach 1:
The patent extracts the rotation axis function from the traditional shaft structure. Instead of using a protruding shaft, the invention uses a virtual rotation axis defined by the intersection of guide grooves, allowing the rotation center to be located within the housing rather than protruding outward, thus maintaining rotation stability while increasing inner surface area.
Solution Approach 2:
The patent introduces guide grooves as intermediary elements that constrain the movement of link shafts. These guide grooves mediate between the link shafts and the housing, providing the necessary rotational constraint without requiring a protruding shaft, thereby achieving both stability and increased effective area.
2Area of stationary object
If C-shaped pivot portions or hinge rings slide in arc-like grooves, then the hinge can rotate without a shaft, but it is difficult to generate a click at a predetermined rotation angle
Solution Approach 1:
The patent segments the rotation control function into multiple components: guide grooves for constraining movement paths, link shafts for transmitting motion, and torque generating mechanisms for providing tactile feedback. This segmentation allows each component to be optimized independently, enabling click generation without requiring a protruding shaft.
Solution Approach 2:
The patent replaces the traditional mechanical click generation mechanism (relying on physical shaft engagement) with a torque generating mechanism that uses elastic deformation of leaf springs. This substitution maintains the click feedback function while allowing a shaftless design that increases inner surface area.
3Area of stationary object
If a shaftless hinge structure is used, then the inner surface area is increased, but the click strength at predetermined rotation angles is insufficient
Solution Approach 1:
The patent changes the physical parameters of the torque generating mechanism by using leaf springs with specific elasticity coefficients and dimensions. By adjusting the spring thickness, length, and material properties, the system generates sufficient click strength (torque) without requiring a protruding shaft, thus maintaining both increased surface area and adequate force feedback.
Data Source
AI summary
Hinge (10) includes first case (11) having an insertion hole through which a first hinge shaft (17) is inserted and a guide groove guiding first link shaft (23), second case (12) having a first insertion hole and a second insertion hole through which second hinge shaft (19) and third hinge shaft (21) are respectively inserted and a guide groove guiding second link shaft (25), and a link mechanism that maintains intervals between first hinge shaft (17), second link shaft (25) and center shaft (27), intervals between second hinge shaft (19), first link shaft (23), and center shaft (27), and intervals between third hinge shaft (21), first link shaft (23), and center shaft (27), and a first member and a second member are supported with first case (11) and second case (12) respectively such that the first member and the second member are rotatable about a virtual rotation axis.