Counter-Rotating Propeller Pod Drive Layout for Compact Redundancy

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Solution Overview

Problem

Conventional CRP pod propulsion systems are heavy, large, and lack redundancy, with independent operation of two-motor CRP pods failing to provide significant redundancy in the event of a motor or drive failure.

Innovation Solution

A CRP pod propulsion system with interdependent electric drives controlling two counter-rotating propellers, allowing simultaneous operation of both motors when one drive fails, and featuring a single bearing shaft line for compactness and redundancy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If two independent shaft lines with two sets of bearings are used in conventional CRP pods, then each propeller can be driven independently, but the system becomes heavier and larger

Engineering Contradiction:
Improveindependent propeller operationVSAvoidpod weight
Core Design Contradiction:
Ease of operationVSWeight of moving object

Solution Approach 1:

The patent merges two independent shaft lines into a single shared shaft line with one set of bearings that supports both propellers. This consolidation eliminates duplicate bearing components and reduces overall structural weight while maintaining the capability for independent propeller operation through separate electric motors coupled to the shared shaft line.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single shared shaft line and bearing assembly are designed to serve dual functions by supporting both the first and second propellers. The universal bearing structure can accommodate variable loads from either or both propellers operating independently or together, providing multi-functional support that reduces component count and weight.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of operation

If two independent shaft lines with two sets of bearings are used in conventional CRP pods, then each propeller can be driven independently, but the system becomes larger

Engineering Contradiction:
Improveindependent propeller operationVSAvoidpod volume
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

The patent merges two independent shaft lines into a single shared shaft line with one set of bearings that supports both propellers. This consolidation eliminates duplicate bearing components and reduces overall structural weight while maintaining the capability for independent propeller operation through separate electric motors coupled to the shared shaft line.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single shared shaft line and bearing assembly are designed to serve dual functions by supporting both the first and second propellers. The universal bearing structure can accommodate variable loads from either or both propellers operating independently or together, providing multi-functional support that reduces component count and weight.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If conventional CRP pods use two independent shaft lines, then redundancy is provided, but the system lacks significant redundancy in the event of motor or drive failure

Engineering Contradiction:
Improvesystem redundancyVSAvoidshaft line configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges two independent shaft lines into a single shared shaft line with one set of bearings that supports both propellers. This consolidation eliminates duplicate bearing components and reduces overall structural weight while maintaining the capability for independent propeller operation through separate electric motors coupled to the shared shaft line.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single shared shaft line and bearing assembly are designed to serve dual functions by supporting both the first and second propellers. The universal bearing structure can accommodate variable loads from either or both propellers operating independently or together, providing multi-functional support that reduces component count and weight.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Weight of moving object

If a single shared shaft line with one set of bearings is used, then weight and size are reduced, but the system must maintain reliability and redundancy

Engineering Contradiction:
Improvepod weightVSAvoidsystem redundancy
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent merges two independent shaft lines into a single shared shaft line with one set of bearings that supports both propellers. This consolidation eliminates duplicate bearing components and reduces overall structural weight while maintaining the capability for independent propeller operation through separate electric motors coupled to the shared shaft line.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements parameter changes by allowing the single shared shaft line system to operate in multiple operational modes: both propellers operating simultaneously at reduced power levels, or one propeller operating at full power while the other is offline. This flexibility in operational parameters maintains system reliability and redundancy despite the simplified single shaft line configuration.

Inventive Principle:
Principle #35Parameter changes

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 system achieves reduced weight and size, improved hydrodynamic efficiency, and full redundancy with independent, compact propulsion modules, enabling efficient operation even in the event of a failure.

Implementation Method 1

a first electric motor (i) for rotating the first propeller and (ii) electrically coupled to a first drive

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Data Source

PatentEP4215434B1Counter rotating propeller pod electrical arrangement
Publication Date: 2026.04.15 GE ENERGY POWER CONVERSION TECHNOLOGY LTD(GB)
  • EP4215434B1 patent drawingFigure 1A~1B
  • EP4215434B1 patent drawingFigure 2
  • EP4215434B1 patent drawingFigure 3A~3B

AI summary

The disclosure relates to a pod propulsion system (300) including first and second counter rotating propellers (318, 322) for providing thrust to propel a marine vessel. The pod propulsion system (300) includes a first electric motor (314) for rotating the first propeller (318) and electrically coupled to a first drive (304) that is configured to control the first electric motor (314). The pod propulsion system (300) also includes a second electric motor (316) for rotating the second propeller (322) and electrically coupled to a second drive (306) that is configured to control the second electric motor (316). The first and second drives (304, 306) respectively control the first and second electric motors (314, 316) interdependently.