Super Elastic Wire Hinge Torque Stability
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Solution Overview
Problem
Hinges in portable information handling systems experience unpredictable torque due to wear and lubricant migration, leading to reduced performance and increased calibration needs.
Innovation Solution
A super elastic wire under tension is used to compress friction elements, providing a consistent and repeatable torque without the need for lubrication, as the low spring rate of the wire reduces sensitivity to wear and eliminates the need for torque calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If Bellville washers are used as springs to generate high torque, then the load generated is high, but the torque becomes sensitive to wear and lubricant migration over time
Solution Approach 1:
The patent changes the spring rate parameter from very high (Bellville washers) to low (super elastic wire). This parameter change makes the compression less sensitive to wear and lubricant migration, maintaining predictable torque over time while still generating sufficient load through the low spring rate mechanism
Solution Approach 2:
The patent substitutes the mechanical spring system (Bellville washers requiring calibration and lubrication) with a super elastic wire system that uses material science properties (super elasticity) to achieve the same torque generation function without the drawbacks of traditional mechanical springs
2Manufacturing precision
If calibration is performed to achieve desired torque, then the initial torque is accurate, but torque changes over time due to wear and lubricant migration
Solution Approach 1:
The super elastic wire automatically compensates for wear and friction changes without requiring external calibration or adjustment. The system self-regulates torque by utilizing the wire's inherent super elastic properties, eliminating the need for manual calibration procedures
Solution Approach 2:
The super elastic wire is pre-configured with specific material properties and tension characteristics during manufacturing that inherently provide stable torque over time. This preliminary design eliminates the need for field calibration and ensures long-term torque stability without requiring subsequent adjustments
3Reliability
If lubrication is applied to reduce wear, then wear is reduced, but the coefficient of friction decreases and torque becomes less predictable
Solution Approach 1:
The patent extracts and eliminates the lubrication component from the hinge system entirely. By removing lubrication, the design accepts higher friction as a trade-off for gaining predictable torque characteristics and eliminating the harmful effects of lubricant migration on torque stability
Solution Approach 2:
The patent converts the potentially harmful high friction into a beneficial feature. The higher coefficient of friction, which would traditionally be seen as a drawback, actually provides more predictable torque and eliminates the problems associated with lubrication, making the friction itself advantageous to the system's performance
4Volume of moving object
If hinge size is reduced for portability, then the system is more compact, but generating sufficient torque becomes more difficult
Solution Approach 1:
The patent changes the spring rate parameter to low, which allows the super elastic wire to generate sufficient compressive force even in a compact hinge design. The low spring rate enables the wire to maintain adequate compression and torque generation within the reduced hinge volume that is necessary for portable information handling systems
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
This solution maintains a constant compression force over a wide range of strains, improving torque stability and allowing for smaller hinge sizes, while eliminating the need for lubrication and calibration, resulting in improved predictability and reduced stress on the hinge components.
Implementation Method 1
a super elastic wire under tension compresses friction elements that provide torque responsive to hinge rotation
Implementation Method 2
Friction elements disposed between portions of the brackets create torque that opposes rotation of the hinges
Data Source
AI summary
An information handling system hinge provides friction against rotational motion to generate torque that regulates housing portion relative position. Friction is generated by compression of friction elements with a super elastic wire under tension. For example, a nickel titanium alloy wire under two to eight percent strain provides a relatively low spring rate having consistent compression even as wear reduces the size of the friction elements.