Rotary Key Force-Unloading Mechanism for Low-Friction Rotation
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Solution Overview
Problem
Existing wearable device keys experience reduced rotation life due to friction between the snap spring and the bourdon tube during rotation, causing abnormal noise.
Innovation Solution
A rotary key force unloading mechanism with a cover cap and bourdon tube connected by an axially retractable elastic member, where the key stem passes through both, and a limiting member prevents separation, ensuring no interaction force between the key and bourdon tube during rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the key and base are connected by a key return spring that applies reaction force to the key, then the key can realize pressing operation, but the snap spring rubs against the bourdon tube during rotation, producing abnormal noise and reducing rotation life
Solution Approach 1:
The invention divides the force transmission path into separate segments: the pressing force is transmitted through the key cap and cover cap to the bourdon tube, while the snap spring is isolated to only provide limiting function. This segmentation prevents the snap spring from participating in force transmission that would cause rubbing during rotation.
Solution Approach 2:
The snap spring is extracted from the force transmission chain and isolated to perform only its limiting function. By removing it from the interaction between the key and bourdon tube, the harmful rubbing effect is eliminated while retaining its essential function of preventing excessive key displacement.
2Stability of the object's composition
If the snap spring is held tightly against the bourdon tube by the key return spring, then the key structure is stable, but friction occurs during rotation causing abnormal noise
Solution Approach 1:
The cover cap acts as an intermediary between the key cap and the bourdon tube, absorbing the pressing force and transmitting it to the bourdon tube without involving the snap spring. This intermediary structure maintains stability while preventing the snap spring from rubbing against the bourdon tube during rotation.
Solution Approach 2:
The invention introduces dynamic characteristics by allowing the cover cap to move axially relative to the bourdon tube during pressing operation. This dynamic design enables the system to absorb force variations and maintain stable operation without creating friction between the snap spring and bourdon tube.
3Productivity
If the key return spring directly applies force to the key, then the pressing operation is efficient, but the rotation life is reduced due to snap spring rubbing
Solution Approach 1:
The force transmission path is segmented into two independent systems: one for pressing (key cap-cover cap-bourdon tube) and one for limiting (snap spring on key stem). This segmentation allows efficient pressing operation while protecting the rotation life by excluding the snap spring from the pressing force chain.
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 mechanism avoids friction and abnormal noise, thereby extending the rotation life of the key by preventing the snap spring from rubbing against the bourdon tube.
Implementation Method 1
the cover cap and the bourdon tube are connected by an axially retractable elastic member; and the elastic member is compressed when the cover cap is pressed by a key cap of the key
Implementation Method 2
the elastic member is a spring, and when the bourdon tube is engaged with the cover cap, the spring is in a compressed state, and an elastic restoring force acts on the cover cap
Data Source
AI summary
Embodiments of the present disclosure disclose a rotary key force unloading mechanism, and an electronic device. The rotary key force unloading mechanism includes a key, a bourdon tube, and a cover cap; the cover cap is axially movable relative to the bourdon tube, and the cover cap and the bourdon tube are connected by an axially retractable elastic member; a stem portion of the key passes through the bourdon tube and the cover cap, so that the elastic member is compressed when the cover cap is pressed by a key cap of the key; and the stem portion of the key is provided with a limiting member for preventing separation, and when no axial force is applied on the key, no interaction forces exist between the limiting member and the bourdon tube.