Electric POD Marine Drive Stator Housing for Higher Torque

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Solution Overview

Problem

Existing electric POD marine drive units face limitations in optimizing torque output due to restricted stator and rotor diameters, which affects propulsion efficiency and hydrodynamic properties.

Innovation Solution

The design features a larger stator diameter without increasing the overall size, utilizing the stator as an outer housing for improved heat dissipation and incorporating soft magnetic composite materials to enhance magnetic interaction and reduce weight, while maintaining optimal efficiency and hydrodynamic performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the stator diameter is increased to improve torque output, then the propulsion power is enhanced, but the overall size of the drive unit increases

Engineering Contradiction:
Improvepropulsion powerVSAvoiddrive unit size
Core Design Contradiction:
PowerVSVolume of moving object

Solution Approach 1:

The stator is designed to serve dual functions: as the electromagnetic component generating the magnetic field and as the outer housing of the drive unit. This multi-functionality allows the stator diameter to be optimized for torque output without requiring additional housing space, effectively resolving the contradiction between increased propulsion power and drive unit size.

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

Solution Approach 2:

The patent merges the stator and the outer housing into a single integrated component. By combining these two previously separate elements, the design eliminates the need for additional space for a separate housing, allowing the stator diameter to be increased for higher torque while maintaining the same overall drive unit dimensions.

Inventive Principle:
Principle #5Merging (Combining)

2Force

If the stator diameter is increased to improve torque output, then the magnetic interaction is enhanced, but the hydrodynamic properties deteriorate due to increased drag

Engineering Contradiction:
Improvetorque outputVSAvoidhydrodynamic drag
Core Design Contradiction:
ForceVSObject-affected harmful factors

Solution Approach 1:

The stator serves as both the electromagnetic structure and the hydrodynamic outer housing. This allows the stator's outer surface to be optimized for hydrodynamic flow while its internal dimensions provide sufficient diameter for enhanced magnetic interaction and torque output, simultaneously addressing both contradictory requirements.

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

Solution Approach 2:

The stator design allows different regions to serve different functions: the outer surface is optimized for hydrodynamic properties with smooth contours reducing drag, while the internal structure provides sufficient diameter and space for enhanced magnetic field interaction and higher torque generation.

Inventive Principle:
Principle #3Local quality

3Strength

If conventional materials are used in the stator, then the structural integrity is maintained, but the weight increases and torque output is limited

Engineering Contradiction:
Improvestructural integrityVSAvoidstator weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The stator is constructed using composite materials that combine high strength-to-weight ratio properties. These composite structures maintain the necessary structural integrity for withstanding operational stresses while significantly reducing the overall weight compared to conventional solid materials, enabling increased stator diameter without proportional weight increase.

Inventive Principle:
Principle #40Composite materials

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 enhances torque output, improves magnetic interaction, reduces drag, and maintains efficiency by leveraging the stator's outer housing for direct cooling and structural integrity, resulting in improved propulsion and maneuverability.

Implementation Method 1

the inner face of the stator comprises a plurality of stator coils

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the inner face is made of a soft magnetic composite

Methodology Applied
Scientific EffectMagnetic properties of soft magnetic composite: Ferromagnetism

Implementation Method 3

the outer face of the stator is facing the water when the drive unit is submerged

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4678531A1An electric POD marine drive unit
Publication Date: 2026.01.14 VOLVO PENTA AB
  • EP4678531A1 patent drawingFigure 1~2
  • EP4678531A1 patent drawingFigure 3~4
  • EP4678531A1 patent drawingFigure 5~6

AI summary

The present disclosure relates to an electric POD marine drive unit, comprising an electric machine being submersible, the electric machine has a rotor and a stator, the rotor is rotatable within the stator, the stator has an inner face arranged opposite the rotor and an outer face, wherein the outer face of the stator functions as an outer housing of a part of the drive unit.