Parallel Torsion Spring with Rolling Coils

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Solution Overview

Problem

Existing leg springs experience tilting moments and friction issues when loaded, leading to wear and inefficiency, particularly in torsional vibration dampers and articulated arrangements.

Innovation Solution

The design features two parallel, counter-rotating spring coils with a small distance between them, allowing the spring legs to protrude and connect at one end, eliminating the need for a mandrel and reducing friction by having the spring windings roll against each other when tensioned, thus minimizing wear and enhancing response behavior.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a mandrel is used to hold the spring coil, then the torsion spring can be held against tilting moment, but the device complexity increases and friction is generated

Engineering Contradiction:
Improvestability against tilting momentVSAvoidcomplexity of mounting structure
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the mandrel from the torsion spring structure. Instead of using a separate mandrel to hold the spring coil, the design allows the spring legs to be loaded directly without requiring any central support element, thereby reducing device complexity while maintaining stability through proper force application geometry

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces a bearing as an intermediary element that facilitates the rotation of the torsion spring without generating friction. This bearing-mediated approach allows the spring to rotate smoothly while eliminating the need for a mandrel, resolving the contradiction between stability and device complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If spring coils are held by mandrel or housing, then the spring structure is stable, but friction and wear occur

Engineering Contradiction:
Improvestructural stabilityVSAvoidwear resistance
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The invention removes the mandrel or housing that traditionally holds the spring coils, eliminating the source of friction and wear. The spring structure is redesigned to function without these supporting elements, achieving both structural stability through alternative means and improved reliability by eliminating frictional contact points

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the mechanical constraint system (mandrel or housing holding the coils) with a bearing-mediated rotation system. This substitution eliminates direct friction between the spring coils and supporting structures, thereby reducing wear and improving reliability while maintaining structural stability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Force

If spring legs are loaded in opposite directions, then tensioning force is generated, but tilting moment is created

Engineering Contradiction:
Improvetensioning forceVSAvoidstability against tilting moment
Core Design Contradiction:
ForceVSStability of the object's composition

Solution Approach 1:

The invention introduces a bearing as an intermediary element that absorbs and neutralizes the tilting moment generated by oppositely directed spring leg loads. The bearing allows the spring to rotate while supporting the tilting forces, enabling tensioning force generation without compromising structural stability

Inventive Principle:
Principle #24Intermediary (Mediator)

4Ease of manufacture

If spring coils are spaced apart, then mounting is easier, but friction occurs when coils rub against each other

Engineering Contradiction:
Improveease of mountingVSAvoidfriction wear
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention eliminates the need for close spacing between spring coils by removing the mandrel constraint system. The coils can be mounted with adequate spacing without requiring tight tolerances, while the bearing-mediated rotation prevents any frictional contact between coils during operation, resolving both mounting ease and friction wear issues

Inventive Principle:
Principle #2Taking out (Extraction)

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 allows for efficient tensioning without generating moments, reduces frictional wear, and improves the damping effect in torsional vibration dampers and articulated arrangements, enabling smooth operation with low breakaway torque and increased durability.

Implementation Method 1

Because of the opposing winding of the spring coils, the coils roll against each other without rubbing when the spring legs are moved towards each other to tension the torsion spring.

Methodology Applied
Scientific EffectRolling friction: Friction

Implementation Method 2

The torsion spring according to the invention has two spring coils that are wound in opposite directions and arranged parallel to one another.

Methodology Applied
Scientific EffectOpposing winding:

Implementation Method 3

Due to its frictionless design, the torsion spring according to the invention exhibits excellent response characteristics without breakaway force or breakaway torque.

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3056757B1Leg spring and torsional vibration damper
Publication Date: 2019.03.13 FEDERNTECHN KNORZER
  • EP3056757B1 patent drawingFigure 1
  • EP3056757B1 patent drawingFigure 2
  • EP3056757B1 patent drawingFigure 3

AI summary

The invention relates to a torsion spring (1) with two opposing, parallel, and mutually contacting spring coils (2). When the torsion spring (1) is tensioned, the spring coils (2) roll against each other with minimal friction and wear. The invention further relates to a torsional vibration damper with such torsion springs (1).