Foldable Hinge Gear Assembly for Synchronous Screen Motion
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Solution Overview
Problem
In foldable mobile phones, the large gear moment tolerances of synchronous transmission gearsets lead to gear rotation lag, affecting the synchronous rotation of main-body parts, which compromises the folding and unfolding mechanism of flexible display screens.
Innovation Solution
A foldable apparatus with a rotating shaft base, main bodies, and a synchronous transmission assembly featuring bevel gears and spur gears that engage coaxially, ensuring synchronous rotation and reducing volume by eliminating center distance tolerance between gears, thus preventing idling and enhancing the folding/unfolding efficiency of flexible display screens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a synchronous transmission gearset with multiple gears in the same rotation plane is used, then the folding and unfolding mechanism can be implemented, but gear moment tolerances are large causing gear rotation lag and affecting synchronous rotation effect
Solution Approach 1:
The patent transitions from a planar gear arrangement (all gears in the same rotation plane) to a spatial arrangement where gears are distributed across different rotation planes. The first bevel gear is in a first rotation plane, while the second bevel gear and spur gear are in a second rotation plane perpendicular to the first. This dimensional change eliminates the accumulation of gear moment tolerances that occurs in planar arrangements, thereby improving synchronous rotation effect.
Solution Approach 2:
The transmission system is segmented into multiple independent gear pairs operating in different rotation planes. Instead of having all gears in one plane forming a single transmission chain, the patent divides the transmission into separate stages: the first bevel gear pair in the first rotation plane and the second bevel gear-spur gear pair in the second rotation plane. This segmentation prevents tolerance accumulation and improves manufacturing precision.
2Volume of stationary object
If traditional synchronous transmission gearsets are used, then rotation can be transmitted, but the device volume is larger due to center distance tolerance between gears
Solution Approach 1:
By arranging gears in different rotation planes (spatial distribution), the patent reduces the center distance between corresponding gears compared to planar arrangements. The perpendicular arrangement of the first and second rotation planes allows for more compact positioning, reducing the overall volume of the transmission assembly while maintaining proper gear engagement.
Solution Approach 2:
The patent combines multiple gear functions into a compact spatial arrangement where the first bevel gear, second bevel gear, and spur gear work together in an integrated transmission system. The merging of these gear elements into a coordinated spatial configuration reduces the overall volume compared to separate planar gear trains.
3Productivity
If multiple gears with large moment tolerances are used, then the transmission mechanism can function, but gear rotation lag occurs affecting the folding/unfolding efficiency
Solution Approach 1:
The spatial arrangement of gears in different rotation planes eliminates the cumulative timing errors that occur in planar gear systems. By distributing gears across perpendicular planes, the patent ensures that rotation synchronization is maintained without the lag that would otherwise occur due to tolerance accumulation, thereby improving folding and unfolding efficiency.
Solution Approach 2:
The patent replaces the traditional planar mechanical gear train with a spatial gear system using bevel gears and spur gears in perpendicular planes. This substitution of the mechanical arrangement (from planar to spatial) fundamentally changes how torques and timing are transmitted, eliminating the rotation lag problem inherent in planar systems with multiple gears.
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 ensures effective synchronous rotation of main-body parts, improving the folding and unfolding mechanism of flexible display screens by reducing gear lag and maintaining efficient operation across various device states.
Implementation Method 1
two second bevel gears engage with two first bevel gears respectively, and two spur gears engage with each other
Data Source
AI summary
A foldable apparatus and an electronic device are provided. The foldable apparatus includes a rotating shaft base, two main bodies disposed at two opposite sides of the rotating shaft base, and a synchronous transmission assembly connected with the two main bodies. Each main body is provided with a rotating member rotatably connected with the rotating shaft base and a housing fixedly connected with the rotating member. Each rotating member is provided with a first bevel gear at an end. The synchronous transmission assembly includes two combined-gears rotatably connected with the rotating shaft base, each combined-gear includes a second bevel gear and a spur gear coaxial with the second bevel gear, two second bevel gears engage with two first bevel gears respectively, and two spur gears engage with each other.