Coil Spring End-Coil Structure for Low Lateral Force
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Solution Overview
Problem
Conventional coil springs experience a reduction in rigidity at the end portions when the bearing surfaces are elongated around the axial line to prevent lateral force, leading to potential operational issues.
Innovation Solution
The coil spring design includes a first and second end coil part with bearing surfaces extending over at least half of a turn around the axial line, while maintaining a sufficient thickness at the outer end portions by adjusting the displacement lengths in the axial and circumferential directions, thereby preventing rigidity deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the bearing surfaces are elongated around the axial line to prevent lateral force, then the lateral force is reduced, but the rigidity at the end portions deteriorates
Solution Approach 1:
The patent applies local quality by differentiating the structure of end coil parts from the central coil part. Specifically, the end coil parts have bearing surfaces that extend circumferentially to prevent lateral force, while the central coil part maintains a different configuration optimized for elastic force. This localized structural differentiation allows each region to perform its specific function optimally without compromising overall performance.
Solution Approach 2:
The patent employs parameter changes by carefully controlling the displacement length of end coil parts in the axial direction. By setting the displacement length to a specific value (less than the wire diameter), the patent optimizes both the bearing surface extension for lateral force prevention and the thickness for rigidity maintenance. This parameter optimization resolves the contradiction between extending bearing surfaces and maintaining end portion rigidity.
2Area of stationary object
If the displacement length of end coil part is increased to extend bearing surface, then the bearing surface area is increased, but the thickness of end portion is reduced
Solution Approach 1:
The patent resolves this contradiction through precise parameter control. By defining the displacement length of the end coil part in the axial direction as a specific parameter (set to be less than the wire diameter), the patent simultaneously achieves adequate bearing surface area extension and sufficient end portion thickness. This parameter optimization allows the bearing surface to extend circumferentially while maintaining the necessary structural thickness.
Solution Approach 2:
The patent applies partial action by extending the bearing surface circumferentially over a portion of the coil turn rather than completing a full extension. The bearing surface extends from the outer end portion toward the inner end portion along the circumferential direction, providing sufficient lateral force prevention without excessively reducing the end portion thickness. This partial extension achieves the necessary functional coverage while preserving structural integrity.
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 configuration effectively prevents the deterioration of rigidity at the end coil parts even with elongated bearing surfaces, thereby suppressing the occurrence of lateral force during compression.
Implementation Method 1
This coil spring is a component intended to axially exert elastic force when axially compressed
Implementation Method 2
it is known to also produce, in addition to the elastic force in the axial direction, force (lateral force) in the direction perpendicular to the axial direction when compressed
Data Source
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AI summary
A coil spring (1) of this invention includes a first end coil part (10) with a first bearing surface (15) facing to the first side in the axial direction, a second end coil part (20) with a second bearing surface (25) facing to the second side in the axial direction and a central coil part (30) connecting the first and second end coil parts. A displacement length in the axial direction from the outer end portion (11) until the inner end portion (12) of the first end coil part (10) is a thickness of a spring wire (100) forming the coil spring (1) so that a space between the outer end portion (11) of the first end coil part (10) and an inner end portion (31) of the central coil part (30) is zero, and a displacement length in the axial direction between the outer end portion (11) of the first end coil part (10) and a point away along the circumferential direction from the outer end portion (11) toward the inner end portion (12) of the first end coil part (1) by a half of turn around the axial line is less than a half of the thickness of the spring wire (100).