End-Coil Spring Geometry to Suppress 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 frictional forces, wear, and operational issues due to sliding resistance.

Innovation Solution

A coil spring design with specific end and central coil parts, where the space between adjacent coils is configured to maintain an integral number of turns and non-zero distance, preventing the number of active coils from changing during compression, thereby minimizing lateral force production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the coil spring is compressed axially, then elastic force is generated in the axial direction, but lateral force is also produced perpendicular to the axial direction

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

Solution Approach 1:

The coil spring is segmented into three distinct regions: a first end coil part, a central coil part, and a second end coil part. Each region has specific structural characteristics that contribute to reducing lateral force while maintaining elastic force generation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the coil spring are given different local qualities: the end coil parts have bent edge regions that create bearing surfaces, while the central coil part maintains a more uniform structure. This local differentiation allows the spring to minimize lateral force at the ends while preserving elastic functionality in the central region.

Inventive Principle:
Principle #3Local quality

2Strength

If lateral force is produced during compression, then the coil spring can maintain structural integrity, but frictional force increases between the plunger and guide surface

Engineering Contradiction:
Improvestructural integrityVSAvoidfrictional force
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The harmful lateral force component is effectively extracted or eliminated through the specific geometry of the end coil parts. The bent edge regions create bearing surfaces that constrain lateral movement, separating the useful elastic force generation from the harmful lateral force production.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The potential harmful effect of lateral force is converted into a beneficial bearing surface through the bent edge regions. The same structural feature that could cause lateral instability instead creates a positive bearing surface that guides the plunger and reduces friction.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Force

If the number of active coils is increased to maintain elastic force, then the spring becomes more compliant, but the number of active coils may change during compression causing lateral force

Engineering Contradiction:
Improveelastic forceVSAvoidconsistency of active coil number
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The end coil parts are pre-configured with bent edge regions that create bearing surfaces before compression occurs. This preliminary structural arrangement ensures that during compression, the active coil number remains constant and lateral force is minimized from the outset.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Instead of allowing the spring to naturally compress with potential lateral force generation, the design inverts the approach by pre-shaping the end coils to create bearing surfaces that actively prevent lateral force during compression.

Inventive Principle:
Principle #13The other way round (Inversion)

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 design effectively suppresses lateral force generation during compressional operations, reducing frictional forces and wear, and maintaining the required elastic force, thus enhancing the operational reliability of the apparatus.

Implementation Method 1

a coil spring which is obtained by forming a spring wire into a helical shape that axially extends from one side toward the other side... This coil spring is a component intended to axially exert elastic force when axially compressed

Methodology Applied
Scientific EffectElastic force: Elasticity

Data Source

PatentEP3842657B1Coil spring
Publication Date: 2024.12.04 SUNCALL CORP
  • EP3842657B1 patent drawingFigure 1
  • EP3842657B1 patent drawingFigure 2
  • EP3842657B1 patent drawingFigure 3

AI summary

A coil spring (1B) having a first end coil part (10) with a first bearing surface (11), wherein the first end coil part (10) includes a first end coil part edge region (111) that extends from a first end (110) to a first reference point (51) where a space between coils (100) that are adjacent to each other in an axial direction is zero in the natural length state, and also includes a first end coil part transitional region (112) which extends from the first end coil part edge region (111) to a central coil part (30). The coil spring (1B) has the first end coil part edge region (111) bent toward one side in the axial direction of the coil spring (1B) as compared with the first end coil part transitional region (112) and the first bearing surface (11) extends from the first end coil part edge region (111) to the first end coil part transitional region (112) across a border between the first end coil part edge region (111) and the first end coil part transitional region (112).