Hydrostatic Thrust Bearing for Watercraft Propulsion
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Solution Overview
Problem
Conventional watercraft propeller propulsion systems are difficult to maintain due to inaccessible and hard-to-replace bearings, and lack a means to measure propeller thrust forces.
Innovation Solution
A watercraft propeller propulsion system with a gimbal assembly featuring a quick-change journal bearing holder and a hydrostatic thrust bearing assembly that allows for easy maintenance and measures propeller thrust forces using a pressurized oil source to levitate the thrust ring, minimizing friction and enabling remote thrust force measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rolling element bearings are pressed onto the propeller shaft and bolted into the propeller shaft housing, then the bearing assembly provides reliable support, but the bearings become difficult to access and remove and/or replace
Solution Approach 1:
The bearing assembly is segmented into modular components: the propeller shaft housing is divided into a forward section and an aft section that can be separated, and the bearing holder is a distinct removable component. This segmentation allows the bearing to be accessed by simply separating the housing sections rather than disassembling the entire assembly, significantly improving ease of repair while maintaining reliability through proper reassembly of the segmented components.
2Device complexity
If conventional drive systems are used without thrust measurement means, then the system structure remains simple, but there is no means to measure propeller thrust forces
Solution Approach 1:
The bearing holder serves multiple functions: it supports the propeller shaft through the bearing, provides a mounting structure for the thrust cell sensor, and acts as a force transmission element. This multi-functionality allows thrust measurement to be integrated into the existing bearing support structure without adding separate measurement hardware, thereby achieving measurement precision while minimizing increases in device complexity.
3Object-generated harmful factors
If a hydrostatic thrust bearing assembly with pressurized oil source is used to levitate the thrust ring, then friction is minimized and thrust force measurement is enabled, but the device complexity increases
Solution Approach 1:
The hydraulic thrust bearing system merges the lubrication function and thrust measurement function into a single integrated assembly. The pressurized oil source, thrust ring, bearing elements, and thrust cell sensor are combined into one compact unit that simultaneously reduces friction through hydrostatic levitation and enables thrust measurement through the integrated sensor, thereby minimizing the increase in device complexity while achieving both friction reduction and measurement capabilities.
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
The system facilitates easier maintenance with simple tools, reduces friction, and provides a compact design that minimizes vertical thrust components, allowing for more accurate thrust force measurement and improved operational efficiency.
Implementation Method 1
a hydrostatic thrust bearing assembly that allows for easy maintenance and measures propeller thrust forces using a pressurized oil source to levitate the thrust ring, minimizing friction
Data Source
AI summary
A thrust system for a watercraft including a propeller shaft, a propeller shaft housing and a hydraulic thrust bearing assembly. The propeller shaft has an enlarged diameter shoulder, and the housing is positioned around and allows axial movement of the propeller shaft. The hydraulic thrust bearing assembly is axially constrained between the propeller shaft shoulder and the housing. The hydraulic thrust bearing assembly includes an annular cylinder, an annular piston, at least one oil feed passage and at least one oil bleed port. The annular cylinder surrounds the propeller shaft and has a circular groove. The annular piston surrounds the propeller shaft and is movably positioned within the circular groove of the annular cylinder forming a pressurized chamber. Each oil feed passage and oil bleed port allows oil to be communicated relative to the pressurized chamber. The hydraulic pressure developed in the pressurized chamber is proportional to thrust.