Variable Pitch Coil Spring for Fuel Lid Push-Out Device
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Solution Overview
Problem
Conventional push-up devices for fuel lids do not effectively control flapping during closure, affecting operability.
Innovation Solution
A push-up device with a tube-shaped case, a slidably held rod, an elastic urging mechanism with varying pitch coil spring, and a cam-type lock mechanism that controls the rod's movement to minimize initial reaction force and stabilize compression deformation, ensuring smooth lid closure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional spring mechanism is used to push out the fuel lid, then the fuel lid can be opened, but flapping occurs during closure which degrades operability
Solution Approach 1:
The patent applies parameter changes by designing a coil spring with non-uniform pitch, where the pitch varies along the length of the spring. This creates a progressive urging force that changes during compression, allowing the spring to provide gentle initial resistance that increases gradually, thereby controlling flapping during fuel lid closure while maintaining ease of operation
Solution Approach 2:
The patent implements dynamics by creating a lock mechanism that transitions between locked and unlocked states based on the rod's position. The lock mechanism engages at specific stroke positions to control flapping, providing dynamic adaptation during the closing operation rather than static resistance throughout the entire motion
2Speed
If the urging force increases rapidly at initial stroke, then the rod can be pushed into the case quickly, but flapping of the fuel lid increases
Solution Approach 1:
The coil spring's pitch is designed to create a progressive urging force profile, with larger pitch at the initial stroke providing lower resistance for faster closing, and smaller pitch at later strokes providing increased resistance to control flapping as the lid approaches closed position
3Device complexity
If a uniform pitch coil spring is used, then the configuration is simple, but the urging force is constant which cannot control flapping effectively
Solution Approach 1:
The patent applies local quality by creating different pitch sections within the same coil spring. The spring has larger pitch in certain sections and smaller pitch in other sections, allowing different parts of the spring to provide different urging forces at different stages of compression, enabling flapping control while maintaining a relatively simple single-spring configuration
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 device improves operability by reducing initial reaction force and stabilizing compression, effectively controlling flapping and enhancing the closing operation of the fuel lid.
Implementation Method 1
an urging mechanism positioned between the case and the rod, and compressed by an elastic deformation inside the case so as to urge the rod in a direction protruding from the inside of the case
Data Source
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AI summary
A coil spring of a push-up device for pushing out a fuel lid in an open direction includes a large pitch portion and small pitch portion, which have different pitches. Therefore, when the fuel lid is being closed, the coil spring, which pushes a rod into a case, has an increase rate of an urging force at an initial stroke less than an increase rate of the urging force at a later stroke following the initial stroke.