Open-Spoke Screw Compressor Gears for Vibration Damping

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Solution Overview

Problem

Oil-free screw compressors using high-speed motors with small gearboxes are prone to vibration issues, leading to increased costs and energy inefficiencies due to the need for flexible couplings, which wear out and absorb energy.

Innovation Solution

Incorporating gears with spokes between the rim and hub in the gearbox to enhance stability and flexibility, reducing torsional and axial vibrations, and using damping materials in the gear spaces to further dampen vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a high-speed motor with a small gearbox is used, then cost and energy efficiency are improved, but vibration problems worsen

Engineering Contradiction:
Improveenergy efficiencyVSAvoidvibration
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent applies the dynamics principle by making the gearbox structure adaptable to vibration frequencies. The open-spoke gear design allows the gearbox to dynamically respond to and dampen torsional vibrations through its flexible structure, while maintaining the high-speed operation characteristics needed for energy efficiency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the structural parameters of the gearbox by transitioning from a closed rigid structure to an open-spoke design. This parameter change reduces the gearbox's resistance to torsional vibrations, allowing it to accommodate and dampen vibrations while maintaining the high-speed motor operation that provides energy efficiency.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If a flexible coupling is used to dampen vibrations, then vibration stability is improved, but device complexity and cost increase

Engineering Contradiction:
Improvevibration stabilityVSAvoidgearbox complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent merges the vibration damping function into the gearbox structure itself by designing open spokes that inherently provide torsional flexibility. This eliminates the need for a separate flexible coupling component, reducing device complexity while maintaining vibration stability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the vibration damping function from a separate flexible coupling component and integrates it directly into the gearbox structure through the open-spoke design. This removes the need for an additional component while achieving the same vibration stabilization effect.

Inventive Principle:
Principle #2Taking out (Extraction)

3Object-affected harmful factors

If a flexible coupling is used, then vibration damping is improved, but reliability worsens due to wear and tear

Engineering Contradiction:
Improvevibration dampingVSAvoidcomponent reliability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The gearbox structure serves itself by providing vibration damping through its own open-spoke design rather than relying on a separate flexible coupling component. The rigid gearbox structure with open spokes inherently dampens vibrations through its geometry, eliminating components that would wear out and requiring replacement.

Inventive Principle:
Principle #25Self-service

4Object-affected harmful factors

If a flexible coupling is used, then vibration damping is improved, but energy efficiency worsens due to energy absorption

Engineering Contradiction:
Improvevibration dampingVSAvoidenergy efficiency
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The open-spoke gear design dynamically responds to vibrations by allowing controlled movement that dissipates vibrational energy without creating significant energy losses in the power transmission path. The flexible structure accommodates torsional vibrations while maintaining efficient power transfer from the motor to the compressor element.

Inventive Principle:
Principle #15Dynamics

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 solution effectively reduces vibrations and energy losses, making the gearbox more robust and efficient while minimizing the need for flexible couplings and reducing material usage, thus improving the overall performance and reliability of the screw compressor.

Implementation Method 1

The spaces between the spokes are filled with a damping material

Methodology Applied
Scientific EffectDamping: Damping

Implementation Method 2

filled with a damping material to further dampen vibrations

Methodology Applied
Scientific EffectViscous damping: Viscous Damping

Implementation Method 3

use is made of a flexible coupling. This will not only facilitate alignment between the motor and the first rotor

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3676514B1Screw compressor
Publication Date: 2021.12.15 ATLAS COPCO AIRPOWER NV
  • EP3676514B1 patent drawingFigure 1~2
  • EP3676514B1 patent drawingFigure 3~4
  • EP3676514B1 patent drawingFigure 5

AI summary

Screw compressor comprising a first rotor (4) and a second rotor (5), each rotor (4, 5) provided with a synchronisation gear (13, 14), said screw compressor (1) further provided with an electric motor (12) and one or two driving gears (9, 10) for driving said first rotor (4) or second rotor (5), characterised in that at least one of the synchronisation gears (13, 14) or driving gears (9, 10) is provided with spokes (17) between a rim (16) supporting a gear mesh (15) and a corresponding gear hub (18).