Variable-Pitch Coil Spring for Lower Lateral Force

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Solution Overview

Problem

Conventional coil springs for internal combustion engines and high-pressure pumps produce lateral forces during compression, leading to increased friction and wear, which can cause operational problems.

Innovation Solution

A coil spring design with specific regions of varying helical space and pitch angles, including a first end region with increased space, a reference region, and a second end region with reduced space, along with transitional regions to maintain non-zero space during compression, effectively suppressing lateral force production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the coil spring is compressed, then elastic force is generated, but lateral force is produced which increases friction and wear

Engineering Contradiction:
Improveelastic forceVSAvoidlateral force
Core Design Contradiction:
ForceVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by creating different pitch regions (first pitch region with larger pitch, second pitch region with smaller pitch) at different locations along the coil spring. This localized variation in pitch allows the spring to generate elastic force while controlling lateral force distribution, reducing friction and wear at specific contact points during compression.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the geometric parameter of pitch along the length of the coil spring. By varying the pitch from the first pitch region to the second pitch region, the spring optimizes its mechanical properties to reduce lateral force while maintaining elastic force generation, thereby minimizing harmful friction and wear effects.

Inventive Principle:
Principle #35Parameter changes

2Force

If the space between coils is reduced to increase elastic force, then the number of active coils increases, but the space between coils becomes zero causing increased lateral force

Engineering Contradiction:
Improveelastic forceVSAvoidlateral force
Core Design Contradiction:
ForceVSObject-generated harmful factors

Solution Approach 1:

The patent divides the coil spring into different pitch regions where the first pitch region maintains larger spacing between coils compared to the second pitch region. This local differentiation ensures that the space between coils never becomes zero even when the number of active coils is increased, thereby preventing the generation of excessive lateral force while maintaining sufficient elastic force.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the coil spring into multiple pitch regions with different characteristics. The first pitch region with larger pitch and the second pitch region with smaller pitch work together to balance the number of active coils with adequate spacing, preventing coil contact and lateral force generation while maintaining elastic force output.

Inventive Principle:
Principle #1Segmentation

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 design effectively prevents the space between coils from becoming zero during compression, significantly reducing lateral force production and maintaining the number of active coils, thus minimizing friction and wear.

Implementation Method 1

This coil spring is a component intended to axially exert elastic force when axially compressed

Methodology Applied
Scientific EffectElastic force: Elasticity

Data Source

PatentEP3425235B1Coil spring
Publication Date: 2021.04.07 SUNCALL CORP
  • EP3425235B1 patent drawingFigure 1
  • EP3425235B1 patent drawingFigure 2
  • EP3425235B1 patent drawingFigure 3

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 is configured such that the number of turns of the helical space is greater than 1 and the space between coils in a terminal position is greater than the reference value L. The helical space has a first transitional region between the terminal position of the first end region and the reference region, the first transitional region being configured so that the distance of space between coils is reduced from the terminal position of the first end region along the helical shape of the helical space toward the other side in the axial direction and becomes the reference value L.