Foldable Device Rotating Shaft With Gear-Rack Wrinkle Control
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Solution Overview
Problem
Foldable electronic devices with flexible screens face issues of wrinkle generation in the extended state due to the design of existing rotating shafts, which reduces the screen's service life and aesthetic appeal.
Innovation Solution
A rotating shaft design featuring a rotating bearing, gear, first and second rotating arms, and a rack bar that mesh with the gear, allowing for adjustable extension and folding mechanisms to prevent wrinkles, with optional features like flexible or elastic rack bars and a partition wheel to reduce friction and enhance structural reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a simple rotating shaft is used to connect the first housing and second housing, then the device structure is simple and easy to manufacture, but the flexible screen generates wrinkles in the extended state reducing service life
Solution Approach 1:
The rotating shaft is divided into multiple functional components: a rotating bearing for rotation, a gear for transmission, a rack bar for linear motion conversion, and rotating arms for force transmission. This segmentation allows each component to perform its specific function, preventing screen wrinkles while maintaining manufacturability through modular assembly.
Solution Approach 2:
The rack bar acts as an intermediary component between the rotating gear and the rotating arms. It converts the rotational motion of the gear into linear push-pull forces that act on the rotating arms, enabling precise control of the housing movement to prevent screen wrinkling without requiring direct complex mechanical linkages.
2Adaptability or versatility
If the first housing and second housing are connected by a rotating shaft, then the flexible screen can be extended for viewing, but the screen generates wrinkles due to length reduction in perpendicular direction
Solution Approach 1:
The mechanism dynamically changes the geometric parameters of the housing arrangement. During extension, the rotating arms adjust the relative position and orientation of the first and second housings, maintaining optimal screen tension and preventing wrinkles while enabling the screen to extend for viewing purposes.
Solution Approach 2:
The rotating shaft mechanism provides dynamic adjustment capability, allowing the housing connection to adapt during screen extension and folding. The rotating arms and rack bar system enables real-time parameter adjustment to maintain screen flatness during operation, preventing wrinkles while preserving extension functionality.
3Ease of operation
If a rotating shaft mechanism is implemented, then the flexible screen can fold for portability, but the device occupies more space compared to simple folding
Solution Approach 1:
The rack bar is designed to wind around the periphery of the gear when not in use, creating a compact nested configuration. This nesting principle allows the mechanism to occupy minimal space in the folded state while providing sufficient travel range for screen extension, thereby improving portability without excessive volume increase.
Solution Approach 2:
The mechanism utilizes rotational motion in one dimension (around the rotating bearing) to achieve linear displacement in another dimension (along the screen extension direction). This dimensional transformation allows compact folding while maintaining effective screen extension capability, reducing the volume penalty associated with the rotating shaft mechanism.
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 effectively prevents wrinkles in the extended state, enhancing the service life and aesthetic quality of the flexible screen by allowing for symmetrical and smooth extension, while also reducing the occupied space in the folded state.
Implementation Method 1
a gear sleeved on the rotating bearing; a rack bar meshing with the gear
Implementation Method 2
a rack bar meshing with the gear, where the first rotating arm drives the gear to rotate around the rotating bearing, so that a second end of the second rotating arm generates a push-pull force
Data Source
AI summary
A rotary shaft and an electronic device having the rotary shaft, the rotary shaft being applied to a foldable electronic device, and the rotary shaft comprising at least one rotary shaft assembly, wherein the rotary shaft assembly comprises: a rotation shaft, a gear sleeved on the rotation shaft, and a first rotating arm, an end of the first rotating arm being fixedly connected to the gear; and a second rotating arm, a first end of the second rotating arm being provided with a rack that engages with the gear. The first rotating arm drives the gear to rotate about the rotation shaft such that a second end of the second rotating arm moves toward a direction away from or close to the rotation shaft.