Aquatic Propulsion Unit with Integrated Bearing Fluid Conditioning
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Solution Overview
Problem
The existing propulsion units for aquatic vehicles face issues with hydraulic fluid degradation due to high stresses, leading to premature wear of shaft bearings and increased clutter and overpressure from conditioning modules connected by ducts passing through the azimuth bearing, which results in inefficient operation and reduced bearing lifespan.
Innovation Solution
A propulsion unit design that uses a supply duct connecting the azimuth bearing and shaft bearing to circulate cooled hydraulic fluid, eliminating the need for a conditioning module and reducing clutter by integrating the conditioning loop within the hull element, thus minimizing ducts and overpressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conditioning module is provided outside the mobile casing to condition hydraulic fluid in shaft bearings, then the hydraulic fluid can be cooled and lubricating properties maintained, but significant clutter is caused and ducts must pass through the azimuth bearing creating complexity
Solution Approach 1:
The patent merges the azimuth bearing and shaft bearing into a single integrated bearing assembly, where the azimuth bearing housing contains both the azimuth bearing itself and the shaft bearing. This integration eliminates the need for separate ducts to pass through the azimuth bearing to reach the shaft bearing, as the conditioning module can service both bearings through a unified structure. The hydraulic fluid circulation system is simplified by this merged design.
2Ease of operation
If ducts of significant length are used to connect the conditioning module to the closed spaces of shaft bearings, then the conditioning module can be positioned outside the mobile casing, but overpressure appears within the closed spaces leading to inefficient operation and premature wear of sealing devices
Solution Approach 1:
The shaft bearing is nested within the azimuth bearing housing, creating a hierarchical structure where the inner shaft bearing is accessible from the outer azimuth bearing assembly. This nesting allows the conditioning module to service the shaft bearing through the azimuth bearing structure without requiring long external ducts, thereby maintaining pressure balance and preventing overpressure issues that would damage sealing devices.
3Device complexity
If the propulsion unit uses a conventional fixed casing design, then structural simplicity is maintained, but the propulsion unit cannot be steered or oriented effectively
Solution Approach 1:
The patent transforms the static, fixed casing design into a dynamic, steerable propulsion unit by introducing a mobile casing that can pivot relative to the hull element through the azimuth bearing mechanism. This allows the propulsion unit to change orientation and steering angle dynamically while maintaining structural integrity. The mobile casing design enables the propulsion unit to adapt its direction without compromising the simplicity of the overall structure.
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 enhances the lubrication of shaft bearings with cooled hydraulic fluid, reducing wear and clutter, while maintaining efficient operation and extending the lifespan of sealing devices by eliminating the need for complex duct arrangements and overpressure issues.
Implementation Method 1
a supply circuit adapted to supply the closed space of the shaft bearing with hydraulic fluid... a supply duct connecting the closed space of the shaft bearing and the closed volume of the azimuth bearing
Implementation Method 2
These stresses result in heating of the hydraulic fluid contained in the closed space and the loss of its lubricating properties
Implementation Method 3
These stresses result in heating of the hydraulic fluid contained in the closed space
Data Source
AI summary
This propulsion unit for an aquatic vehicle consists of a mobile casing equipped with an azimuth bearing due to its mounting in a pivot connection in relation to a hull element of the aquatic vehicle, the azimuth bearing having a closed volume provided to contain a hydraulic fluid, the propulsion unit having a drive shaft of a propeller, said shaft being mounted rotatably within the mobile casing by means of at least one bearing having a closed space adapted to contain a hydraulic fluid, an electrical machine being adapted to drive the rotary drive shaft in relation to the mobile casing, the propulsion unit having a supply circuit adapted to supply the closed space of the shaft bearing with hydraulic fluid.The supply circuit has a supply duct connecting the closed space of the shaft bearing and the closed volume of the azimuth bearing.