Counter-Rotating Propeller Drive Shaft Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ship propulsion devices with single propellers suffer from energy loss and inefficiency due to the difficulty in achieving center alignment and efficient lubrication, particularly in counter rotating propeller systems, and when applied to azimuth thruster systems, these issues persist, necessitating a more effective counter rotating propeller type propulsion device.
Innovation Solution
A ship propulsion device that enables counter rotation of two propellers without an outer shaft, utilizing a drive shaft with a counter rotation unit comprising bevel gears and a motor, which reverses the rotation direction of the drive shaft to transmit it to the front propeller, eliminating the need for a hollow outer shaft and simplifying installation and lubrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a hollow outer shaft is used in the counter rotating propeller type propulsion device, then the counter rotation of propellers is achieved, but the hollow outer shaft has difficulty in center alignment with respect to the inner shaft upon installation
Solution Approach 1:
The invention removes the hollow outer shaft from the system entirely. Instead of using a complex hollow outer shaft structure that causes alignment difficulties, the patent extracts this component and replaces it with a simplified configuration where the front propeller is directly coupled to the counter rotation mechanism through bevel gears, eliminating the alignment problem at its source.
Solution Approach 2:
The invention segments the counter rotation mechanism into independent components: the inner shaft with rear propeller, the counter rotation unit with bevel gears, and the front propeller assembly. This segmentation allows each component to be installed and aligned independently, with the counter rotation unit serving as a fixed intermediary that eliminates the need for complex hollow shaft alignment.
2Ease of manufacture
If a hollow outer shaft is used in the counter rotating propeller type propulsion device, then the counter rotation of propellers is achieved, but the outer shaft needs an increased lubrication area for reduction in friction
Solution Approach 1:
The invention extracts and removes the hollow outer shaft that requires extensive lubrication. By eliminating this component, the patent removes the associated lubrication complexity and friction reduction requirements, replacing the function with a gear-based counter rotation unit that has different, simpler lubrication needs.
3Power
If counter rotation of the inner shaft and outer shaft is implemented, then propulsive force is generated, but shear of lubrication layer occurs making efficient lubrication difficult
Solution Approach 1:
The invention replaces the mechanical shaft-in-shaft counter rotation system with a gear-based mechanism. Instead of relying on lubrication between rotating shafts, the patent uses bevel gears to achieve counter rotation, substituting the lubrication-dependent mechanical system with a gear transmission system that has different lubrication characteristics and eliminates the shear problem.
4Ease of operation
If a typical planetary gear mechanism is used as the counter rotation unit, then counter rotation is achieved, but the hollow outer shaft alignment and lubrication problems persist
Solution Approach 1:
The invention extracts and removes the hollow outer shaft that causes alignment and lubrication problems. By taking out this problematic component, the patent simplifies the overall structure while maintaining the counter rotation function through a more straightforward gear mechanism without the complexity of a hollow shaft system.
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 enhances propulsion efficiency, simplifies installation, reduces lubrication requirements, and minimizes friction and alignment issues, while maintaining effective counter rotation for enhanced propulsion performance across all directions.
Implementation Method 1
a counter rotation unit configured to reverse rotating direction of the drive shaft and transmit reversed rotation to the front propeller
Data Source
AI summary
Disclosed are a propulsion device for a ship and a ship having same. The propulsion device, according to an embodiment of the present invention, comprises: a rear propeller fixed to a driveshaft; a front propeller positioned in front of the rear propeller, and supported rotably on the driveshaft; and a counter rotation device for reversing and transmitting the rotation of the driveshaft to the front propeller; a motor for rotating the driveshaft; and an housing, which extends from to the lower part of the hull, and which is installed so as to envelope the counter rotation device and the motor.