Ship Drive Pivot Bearing Offset Reduces Flange Bending
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Solution Overview
Problem
Existing ship propulsion systems face challenges in absorbing propeller thrust and weight, managing torque and bending moments, and reducing vibrations to prevent noise and damage, while maintaining fatigue strength and cost-effectiveness.
Innovation Solution
A ship propulsion system with a pivot bearing arrangement where the propeller shaft's axis of rotation passes close to the pivot bearing's axis, optimizing bending moments and allowing for deformations compensation, combined with a three-point bearing system incorporating vibration-absorbing elements to minimize stress on components and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the propeller shaft's rotational axis passes through the pivot bearing's rotational axis, then the bending moment at the connecting flange is minimized, but the torque support capability is reduced
Solution Approach 1:
The patent introduces a vertical offset between the propeller shaft's rotational axis and the pivot bearing's rotational axis, creating a three-dimensional configuration rather than a coplanar arrangement. This dimensional change allows the system to simultaneously minimize bending moments in the horizontal plane while maintaining torque support through the vertical offset, effectively resolving the contradiction by operating in multiple spatial dimensions.
2Object-affected harmful factors
If the bearing arrangement is designed to absorb vibrations, then noise and vibration damage are reduced, but the complexity of the bearing arrangement increases
Solution Approach 1:
The patent combines multiple functions into the bearing arrangement by integrating vibration absorption capabilities directly into the bearing structure itself. Rather than adding separate vibration damping components, the bearing arrangement is designed to simultaneously support mechanical loads and absorb vibrations, thereby reducing noise and vibration damage without significantly increasing system complexity.
3Force
If the connecting flange is designed to withstand high stress, then the propulsion system can handle high propeller thrust, but the connecting elements become larger and heavier
Solution Approach 1:
The patent employs the counterbalancing effect of the offset between the propeller shaft axis and pivot bearing axis to create a compensating torque that opposes the bending moment on the connecting flange. This counteracting force allows the connecting flange to handle high propeller thrust loads without requiring excessive reinforcement, thereby reducing the weight and size of the connecting elements while maintaining structural integrity.
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 reduces stress on components, enhances fatigue strength, and minimizes noise and vibrations, leading to a more durable and comfortable propulsion system with improved passenger comfort and reduced wear on ship components.
Implementation Method 1
at least one of the several bearing points in the bearing arrangement should advantageously be designed as a pivot bearing. The resulting ability to rotate the drive unit around the pivot bearing's axis of rotation enables compensation for deformations of the drive unit during operation.
Implementation Method 2
The bearing arrangement must absorb vibrations, particularly those caused by a running propulsion machine, such as an internal combustion engine. This prevents these vibrations from being transmitted to the ship's hull and causing disturbing noise or vibration damage to the hull or other components.
Data Source
AI summary
The invention relates to a ship drive (1) comprising a drive machine (2), a transmission (3), a propeller shaft (5) which is driven by the transmission (3), and a bearing arrangement with which the ship drive (1) can be secured to a hull (6) of the ship. The drive machine (2) and the transmission (3) are connected to each other by means of a connecting flange (4) and are arranged within the hull (6) of the ship. The invention is characterized in that a first bearing point which is designed as a rotary bearing (7) is arranged in relation to the rotational axis (15) of the propeller shaft (5) such that a bending moment (9) at the connecting flange (4) is optimized, said bending moment being caused by the propeller thrust (8) and the weight of the drive machine (2) and the transmission (3).