Variable-Pitch Coil Spring Structure for Low-Friction Compression
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Solution Overview
Problem
Conventional coil springs for internal combustion engines and high-pressure pumps generate lateral forces during compression, leading to increased friction and wear, which can cause operational problems due to sliding resistance.
Innovation Solution
A coil spring design with a helical shape where the space between coils has specific regions with varying pitch angles and extensions, preventing the space between coils from becoming zero during compression, thereby suppressing lateral force production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the space between coils is reduced to zero at end regions, then the coil spring achieves compact structure and maximum compression, but lateral force is generated during compression
Solution Approach 1:
The patent applies local quality by differentiating the pitch characteristics in different regions of the coil spring. The reference region has a specific pitch that maintains a positive space between coils during compression, while end regions may have different pitch characteristics. This localized differentiation ensures that the critical reference region does not generate lateral force while still achieving overall compactness and compression capability.
Solution Approach 2:
The patent changes the pitch parameter in the reference region to a specific value that prevents the space between coils from reaching zero during compression. This parameter adjustment ensures that the coil spring maintains a minimum positive space between coils in the reference region, thereby eliminating lateral force generation while still allowing maximum compression in other regions.
2Object-generated harmful factors
If the number of active coils is increased to reduce lateral force, then lateral force is reduced, but the coil spring becomes longer and more complex
Solution Approach 1:
The patent applies local quality by concentrating the lateral force reduction function in a specific reference region with optimized pitch characteristics, rather than increasing the number of active coils throughout the entire spring. This localized approach reduces lateral force while maintaining a compact overall length by allowing other regions to have fewer coils or different characteristics.
3Object-generated harmful factors
If the pitch angle is increased in end regions, then the space between coils is maintained and lateral force is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by restricting the pitch angle optimization to a specific reference region, rather than requiring precise control throughout the entire coil spring. This localized approach reduces lateral force while minimizing manufacturing precision requirements by allowing greater tolerance in non-reference regions.
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
Effectively reduces lateral force generation during compressional operations, minimizing friction and wear, and maintaining the number of active coils, thus enhancing the operational reliability of the coil spring.
Implementation Method 1
This coil spring is a component intended to axially exert elastic force when axially compressed
Data Source
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AI summary
In the coil spring of the present invention, a helical space defined by a space between coils has a first end region whose space is increased as it extends towards the other side in the axial direction from a first reference point where the space is zero, a reference region whose space is set at a reference value L (L> 0), and a second end region whose space becomes narrow as it extends toward the other side in the axial direction and zero at a second reference point. The first end region has a first end outer part and a first end inner end. In a case where a pitch angle of the space between coils that causes the displacement of the space between coils per turn of the helical space to be L is a reference pitch angle Pa, the pitch angle in the first end outer part is set at Pa while the pitch angle in the first end inner part is set at Pb (Pb>Pa).