Ship Propulsion System Using Segmented High-Speed Motor and Gearbox
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Solution Overview
Problem
Ship propulsion systems with slow-running electric motors require large, heavy, and costly motors to handle low-speed operation, leading to increased weight, space requirements, noise, and higher acquisition costs due to direct drive and rigid installation, which complicates noise reduction and clutch design.
Innovation Solution
Implementing a high-speed electric motor with a speed-reducing gear and elastic bearing support, allowing for decoupling of the electric motor and transmission, reducing noise and weight through a smaller clutch and flexible installation, enabling efficient operation with reduced noise and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a low-speed electric motor is used for direct drive of the propeller shaft, then the motor can provide the required rotary drive power at low speed, but the motor weight and space requirements increase significantly
Solution Approach 1:
The drive system is segmented into two separate functions: a high-speed electric motor for power generation and a mechanical transmission system (gearbox) for speed reduction and torque multiplication. This segmentation allows the motor to operate at its optimal high speed while the gearbox handles the speed conversion to match propeller requirements
Solution Approach 2:
A mechanical transmission system (gearbox) is introduced as an intermediary between the high-speed electric motor and the propeller shaft. This intermediary performs the speed reduction and torque conversion, allowing the motor to remain lightweight while still delivering the required low-speed high-torque output
2Speed
If a low-speed electric motor is used for direct drive, then the motor can operate at propeller speed, but the acquisition costs increase significantly
Solution Approach 1:
The drive system is segmented into two separate functions: a high-speed electric motor for power generation and a mechanical transmission system (gearbox) for speed reduction and torque multiplication. This segmentation allows the motor to operate at its optimal high speed while the gearbox handles the speed conversion to match propeller requirements
Solution Approach 2:
The operating parameters of the electric motor are changed from low-speed high-torque to high-speed high-power. This parameter change allows the use of smaller, more cost-effective motors while achieving the same propulsive output through the mechanical advantage provided by the gearbox
3Reliability
If a rigid installation of the electric motor is used, then the motor can be securely mounted, but structure-borne noise is introduced directly into the propeller shaft and ship's foundation
Solution Approach 1:
Elastic bearing elements are introduced as intermediaries between the motor assembly and the ship's foundation. These elastic elements decouple the rigid mechanical connection, allowing the motor to be securely mounted while filtering out structure-borne noise and vibrations from being transmitted to the propeller shaft and ship foundation
Solution Approach 2:
The noise transmission path is extracted from the rigid mounting structure by using elastic bearing elements. This separation allows the motor to be securely mounted while preventing the transmission of structure-borne noise to critical components
4Adaptability or versatility
If a large clutch is used to decouple the electric motor from the propeller shaft, then the motor can be decoupled, but the device complexity and cost increase
Solution Approach 1:
The operating parameters of the clutch are changed by using the high-speed motor's rotational speed advantage. The clutch operates at higher speed with lower torque requirements, allowing the use of a smaller, simpler clutch design compared to what would be needed for a low-speed direct-drive 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
The solution significantly reduces noise, weight, and acquisition costs by using a high-speed electric motor with a speed-reducing gear and elastic support, allowing for efficient operation with lower noise and mechanical efficiency in both electric motor and diesel/gas turbine modes.
Implementation Method 1
a first bearing which is designed such that the electric motor and the transmission supplied with rotary drive power by the electric motor can be elastically supported on a ship foundation
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The system (1) has a propeller shaft (15) for supplying rotary drive power to a propulsion element (100). A gear box (50) is provided with a gear box input (51) and a gear box output (52) and connected with the propeller shaft over an axial- and angle displacement permitting coupling unit (55). The gear box is provided with a high-speed electromotor (60) and a driven shaft (61) providing rotary drive power. A disk clutch comprises a clutch input and a clutch output. The clutch input is connected with the driven shaft of the electromotor. The clutch output is connected with the gear box input.