Propulsion Unit Bearing Assembly for Dry-Dock-Free Service

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Solution Overview

Problem

Existing propulsion units require dry docking for maintenance and replacement of radial and thrust bearings, which is time-consuming and costly, especially for vessels at sea.

Innovation Solution

The propulsion unit design features a first radial bearing positioned axially inside a first thrust bearing, allowing for maintenance and replacement from within the housing without dry docking, with both bearings being accessible from either an axial or radial direction, enabling service and change without removing the vessel from the water.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If bearings are positioned in conventional locations requiring external access, then bearing support and rotation are ensured, but maintenance and replacement require dry docking which is time-consuming and costly

Engineering Contradiction:
Improvebearing maintenance accessibilityVSAvoiddowntime for dry docking
Core Design Contradiction:
Ease of repairVSLoss of time

Solution Approach 1:

The radial bearing is nested inside the thrust bearing, creating a compact arrangement where the radial bearing is positioned axially inside the thrust bearing. This nesting allows both bearings to be accessed through a single opening in the housing, enabling maintenance without dry docking while maintaining proper mechanical support and rotation functions

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The bearings are arranged in an axial dimension rather than radial arrangement, with the radial bearing positioned axially inside the thrust bearing. This dimensional reorganization allows access to both bearings from the same direction through the housing, transforming the maintenance approach from requiring external access to allowing internal access

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Volume of moving object

If bearings are arranged in a compact configuration, then space utilization is improved, but access for maintenance becomes difficult

Engineering Contradiction:
Improvehousing space utilizationVSAvoidbearing accessibility
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The radial bearing is nested inside the thrust bearing, creating a compact axial arrangement that maximizes space utilization within the housing while maintaining accessibility. This nesting configuration allows both bearings to be serviced through a single opening, combining compactness with ease of maintenance

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The bearing assembly is segmented into two independently replaceable units - the radial bearing and the thrust bearing - arranged in a nested configuration. This segmentation allows each bearing to be accessed and replaced independently through the same opening, maintaining ease of operation despite compact arrangement

Inventive Principle:
Principle #1Segmentation

3Ease of repair

If bearings are positioned for easy external access, then maintenance is simplified, but the housing structure becomes more complex

Engineering Contradiction:
Improvebearing serviceabilityVSAvoidhousing structure complexity
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The nested arrangement of the radial bearing inside the thrust bearing simplifies the housing structure by requiring only a single opening for access to both bearings. This eliminates the need for multiple access points or complex external mounting structures, reducing housing complexity while maintaining ease of repair

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP3892872B1A propulsion unit
Publication Date: 2022.12.28 ABB OY
  • EP3892872B1 patent drawingFigure 1
  • EP3892872B1 patent drawingFigure 2
  • EP3892872B1 patent drawingFigure 3

AI summary

The propulsion unit comprises a housing (20) supported on a vessel. A propeller shaft (30) extends in the housing. The propeller shaft is rotatably supported with a first bearing (100) and a second bearing. A propeller is attached to at least one end of the propeller shaft. The first bearing (100) comprises a first radial bearing (110) and a first thrust bearing (120). The first radial bearing is a sliding bearing positioned axially inside the first thrust bearing. The first bearing is positioned at the first end of the housing and the second bearing being positioned at the second end of the housing or vice a versa.