Fin Stabilizer Sliding-Tooth Drive for Backlash-Free Torque
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Solution Overview
Problem
Traditional fin roll stabilizers for marine vessels face challenges with hydraulic systems, including complexity, maintenance difficulties, environmental concerns, and potential for fires, as well as inefficiencies and backlash issues with direct drive electric motors.
Innovation Solution
An oscillating separate individual sliding tooth drive system using a logarithmic spiral design for improved torque control and reduced backlash, allowing for flexible motor placement and use of standardized components to accommodate varied fin and torque requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If hydraulic systems are used to power fin roll stabilizers, then sufficient torque and power can be delivered, but system complexity increases due to required plumbing, valves, cylinders, pumps, reservoirs, cooling systems, and filters
Solution Approach 1:
The patent extracts and eliminates the hydraulic system entirely, replacing it with a direct-drive electric motor system. This removes all hydraulic components (plumbing, valves, cylinders, pumps, reservoirs, cooling systems, filters) while maintaining the ability to deliver sufficient torque through properly sized electric motors with direct or indirect coupling to the fin shaft.
Solution Approach 2:
The patent substitutes the hydraulic mechanical system with an electrical system. Electric motors provide the driving force, eliminating the need for hydraulic fluid power transmission. This substitution reduces mechanical complexity while maintaining or improving torque delivery capability through modern electric motor technology.
2Power
If hydraulic systems are used for fin roll stabilizers, then power transmission is achieved, but maintenance difficulty increases due to extensive piping and components requiring service
Solution Approach 1:
The patent removes the entire hydraulic system including all piping and components that require maintenance. The electric motor system requires minimal maintenance compared to hydraulic systems, eliminating the need to service pumps, valves, hoses, filters, and reservoirs.
Solution Approach 2:
The electric motor system is inherently more self-contained and requires less external maintenance intervention. Electric motors have fewer moving parts and no fluid systems to maintain, making them more self-service oriented and reducing the need for routine maintenance of piping and components.
3Power
If hydraulic fluid is used in fin roll stabilizers, then power transmission is enabled, but environmental harm occurs through oil leakage into bilge water and ocean
Solution Approach 1:
The patent extracts and eliminates hydraulic fluid from the system entirely. By using electric motors instead of hydraulic systems, there is no hydraulic oil to leak into bilge water or the ocean, completely preventing this source of environmental pollution.
Solution Approach 2:
The patent converts the harmful aspect of hydraulic systems (oil leakage potential) into a benefit by eliminating the hydraulic fluid entirely. The electric motor system provides power transmission without any risk of oil contamination, turning a potentially harmful system into a clean, environmentally friendly alternative.
4Force
If hydraulic systems operate at high pressure, then torque capacity increases, but fire risk increases due to oil misting or vaporization on hot surfaces
Solution Approach 1:
The patent removes the hydraulic system and its high-pressure oil circulation entirely. Electric motors provide torque capacity without using pressurized fluid, eliminating the fire hazard associated with hydraulic oil misting or vaporization on hot surfaces in machinery spaces.
Solution Approach 2:
The patent converts the fire hazard inherent in high-pressure hydraulic systems into a safe operating condition by using electric motors. The harmful combination of high-pressure oil and hot surfaces is eliminated, replacing it with an inherently safer electrical drive system that maintains torque capacity without fire risk.
5Force
If planetary gear sets are used in direct drive electric motors, then torque is transmitted, but backlash and positioning errors increase due to gear wear
Solution Approach 1:
The patent segments the drive system into direct electric motor coupling with the fin shaft, eliminating the intermediate planetary gear set. This direct connection removes the source of backlash and positioning errors that accumulate with gear wear, maintaining precision throughout the system's operational life.
Solution Approach 2:
The patent substitutes mechanical gear transmission with direct electrical-mechanical coupling. Electric motors can provide high torque directly at the shaft without requiring gear reduction, eliminating backlash and positioning errors associated with planetary gear sets while maintaining torque transmission capability.
6Manufacturing precision
If strain wave gear sets are used in direct drive electric motors, then backlash is eliminated, but torque capacity is limited and ratcheting phenomenon occurs under peak conditions
Solution Approach 1:
The patent extracts and eliminates the strain wave gear set entirely, using direct electric motor drive. This removes the torque capacity limitations and ratcheting phenomenon associated with strain wave gears while maintaining precision through direct coupling of the motor to the fin shaft.
Solution Approach 2:
The patent substitutes the strain wave gear mechanism with direct electric motor drive. Modern electric motors can deliver high torque directly without mechanical reduction gears, eliminating both the backlash issue (by having no gears) and the torque capacity limitations of strain wave gears.
Data Source
AI summary
A vessel hull stabilization system includes a housing having a rotatable shaft mounted thereto, the shaft configured to connect to a fin such that the fin is located on an outside of the vessel hull and the housing is located on an inside of the vessel hull. A drive system is mounted to the housing and includes a motor and a drive element. The motor is connected to a central shaft of the drive element and an outer element of the drive element is connected to the fin shaft. The drive element includes a plurality of teeth positioned between the outer element and the central shaft such that when the motor rotates the central shaft, the plurality of teeth oscillate in a direction perpendicular to an axis of the central shaft to interact with and rotate the outer element. A controller receives sensor readings to determine control signals to send to the motor(s) to impart rotation of the fin.