Segmented Stator Rim Thruster for Reduced Gap Losses

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing rim thrusters face challenges with complex and costly installation and maintenance of the underwater electrical active part, particularly the stator, which requires docking the vessel. Additionally, they suffer from high gap losses and require large nozzle cross-sections.

Innovation Solution

The design features a stator that extends only over a partial circumferential area of the rotor, allowing for reduced installation space and improved accessibility for maintenance without docking. This arrangement also minimizes gap losses and offers design flexibility for the gap between the rotor and stator.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the stator completely encloses the rotor in known rim thrusters, then the propulsion forces are well absorbed and the motor structure is stable, but the installation and maintenance of the underwater electrical active part becomes complex and requires docking the vessel

Engineering Contradiction:
Improvepropulsion force absorptionVSAvoidstator maintenance accessibility
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The stator is segmented into a first stator section and a second stator section that can be moved relative to each other. The first stator section remains fixed while the second stator section can be displaced axially to create access to the rotor, enabling maintenance without complete enclosure. This segmentation allows the stator to transition between a closed configuration for reliable force absorption and an open configuration for maintenance accessibility.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If the stator completely encloses the rotor, then the motor structure is stable, but the installation space required is large and the nozzle cross-section must be large

Engineering Contradiction:
Improvemotor structure stabilityVSAvoidnozzle cross-section
Core Design Contradiction:
Stability of the object's compositionVSArea of stationary object

Solution Approach 1:

By dividing the stator into movable sections, the overall structure becomes more compact. The second stator section can be repositioned to reduce the axial length of the motor assembly, allowing for a smaller nozzle cross-section while maintaining structural stability when the sections are in their operational configuration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The stator transitions from a static completely-enclosing structure to a dynamic structure where the second stator section can move axially. This dynamic capability allows the motor to achieve both compact dimensions for reduced installation space and stable operational configuration when the sections are positioned for normal operation.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the stator completely encloses the rotor, then the propulsion forces are well absorbed, but gap losses are high

Engineering Contradiction:
Improvepropulsion force absorptionVSAvoidgap losses
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The segmented stator design allows for optimized positioning of the stator sections relative to the rotor. The first stator section can be positioned to minimize the gap with the rotor for reduced gap losses, while the second stator section provides structural support and can be moved for maintenance. This segmentation enables independent optimization of the gap dimension to reduce energy losses while maintaining force absorption capability.

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

This design reduces installation space and maintenance complexity, enhances fluid dynamics, and minimizes gap losses, resulting in a high-performance electrically driven propeller system that is more efficient and cost-effective.

Implementation Method 1

an electrically driven propeller (2) arranged in the housing with an annular rotor (20) which carries a plurality of propeller blades (21) on its radially inner side and has a stator (22) for driving the rotor (20) on its radially outer side

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4026765B1Ship propulsion system and ship equipped with a ship propulsion system
Publication Date: 2025.06.18 SCHOTTEL
  • EP4026765B1 patent drawingFigure 1
  • EP4026765B1 patent drawingFigure 2~3
  • EP4026765B1 patent drawingFigure 4~5

AI summary

The invention relates to a ship propulsion system, comprising a tunnel-shaped housing (1) and an electrically driven propeller (2) arranged in the housing (1) with an annular rotor (20) which carries a plurality of propeller blades (21) on its radially inner side and has a stator (22) for driving the rotor (20) on its radially outer side, wherein the stator (22) extends only over a partial circumferential region of the rotor (20).