Pump-Jet Watercraft Drive With Slip-Ring-Free Steering Housing

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Solution Overview

Problem

Existing pump-jet watercraft propulsion systems face issues with complex designs that require costly and wear-prone slip rings for energy supply to the stator, and large installation spaces due to shaft-driven motors, leading to inefficiencies and increased maintenance needs.

Innovation Solution

The propulsion system is designed with a housing divided into a stationary inner part and a rotatable outer part, where the stator is fixed to the inner part, and the rotor rotates within the stator, eliminating the need for slip rings and reducing installation space by integrating the drive motor within the housing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the stator is located within the rotatable housing and energy is supplied via slip rings, then the drive can be compact, but the system becomes costly and susceptible to wear

Engineering Contradiction:
Improvedrive compactnessVSAvoidwear resistance
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The housing is divided into two distinct parts: a stationary inner part that houses the stator and a rotatable outer part that contains the rotor and impeller. This segmentation allows the stator to remain fixed while the rotor rotates, eliminating the need for slip rings and their associated wear problems, while maintaining the compact integrated design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The stator is extracted from the rotatable housing and placed in a separate stationary inner part. This extraction removes the stator from the rotating assembly, eliminating the need for sliding contacts and slip rings, thereby solving the wear and reliability issues while preserving the compact drive design.

Inventive Principle:
Principle #2Taking out (Extraction)

2Device complexity

If a shaft-driven motor located in the ship's hull is used, then the drive motor can be separated from the housing, but the design becomes complex and requires large installation space

Engineering Contradiction:
Improvedrive design complexityVSAvoidinstallation space
Core Design Contradiction:
Device complexityVSVolume of stationary object

Solution Approach 1:

The drive motor is merged with the housing by integrating both the motor components (stator and rotor) and the pump jet housing into a single unified structure. The stationary inner part of the housing serves as the stator housing, while the rotatable outer part contains the rotor and impeller, eliminating the need for separate shaft connections and reducing installation space.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rotor is nested within the stator, and the impeller is nested within the rotor assembly. This nested arrangement allows all components to be contained within a compact integrated housing, reducing the overall installation space while simplifying the design by eliminating external shaft connections.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 provides a compact, wear-resistant, and efficient propulsion system with reduced maintenance requirements, minimizing energy supply complexity and maximizing thrust jet pressure while maintaining maneuverability.

Implementation Method 1

a magnetic motor integrated into the housing, comprising an annular stator and a similarly annular rotor rotating within it

Methodology Applied
Scientific EffectElectromagnetic interaction: Electromagnetic Induction

Implementation Method 2

a propeller arranged between the at least one inlet channel and the at least one outlet nozzle, designed as an impeller and rotatable via a drive motor, by means of which water is drawn into the housing via the inlet channel, accelerated and expelled from the housing as a jet of thrust

Methodology Applied
Scientific EffectImpeller rotation: Impeller

Data Source

PatentEP4674748A1Drive for a watercraft
Publication Date: 2026.01.07 SCHOTTEL
  • EP4674748A1 patent drawingFigure 1
  • EP4674748A1 patent drawingFigure 2
  • EP4674748A1 patent drawing

AI summary

The invention relates to a propulsion system (1) for a watercraft, designed as a pump jet, comprising a housing (10) with at least one inlet channel (14) and at least one outlet nozzle (15) communicating therewith, and a propeller arranged between the at least one inlet channel (14) and the at least one outlet nozzle (15), designed as an impeller (13) and rotatable via a drive motor, by means of which water is drawn into the housing (10) via the inlet channel (14), accelerated, and expelled from the housing as a jet of thrust via the outlet nozzle (15), wherein the housing (10) is rotatable about a steering axis (S) by means of a steering drive, and the drive motor comprises an annular stator (11) fixed in the housing (10) and a rotor (12) received therein, which forms the impeller (13).wherein the housing (10) comprises a stationary inner part (100) and an outer part (101) rotatably mounted on the inner part (100) about the control axis (S) and the stator (11) is fixedly connected to the inner part (100).