Pod Propulsion Motor Cooling via Strut Heat Conduction
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Solution Overview
Problem
Pod propulsion devices using electric motors face inefficiencies in cooling, particularly at the upper portion of the motor housing which is not directly exposed to seawater, leading to hot spots and the need for larger motors or cumbersome cooling ducts.
Innovation Solution
A stationary heat conducting means is used to connect the upper portion of the motor housing casing to the outer walls of the strut, utilizing conductive materials like copper, aluminum, or steel to efficiently transfer heat away from the stator, even in areas not directly exposed to seawater, with embodiments including pipe-shaped elements and heat pipes for enhanced cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling ducts are arranged at various locations in the motor housing and strut to cool the hot spot, then cooling effectiveness is improved, but device complexity and space consumption increase
Solution Approach 1:
The cooling function is merged with the existing strut structure by integrating heat conducting means into the strut walls. The strut itself becomes the cooling pathway, eliminating the need for separate cooling ducts and reducing structural complexity while maintaining effective heat removal from the motor housing.
Solution Approach 2:
The strut structure serves dual functions: providing mechanical support and acting as a heat conduction pathway. By making the strut itself the cooling medium through which heat is conducted away from the motor housing, the design achieves multi-functionality without adding dedicated cooling components.
2Reliability
If a motor larger than needed is used to avoid overheating in the hot spot, then cooling reliability is improved, but cost and efficiency worsen
Solution Approach 1:
Instead of uniformly increasing motor size, the invention applies localized thermal management by conducting heat away specifically from the hot spot area through the strut. This targeted approach maintains reliable cooling only where needed, allowing the use of a appropriately-sized motor without oversizing for the entire system.
3Strength
If the upper portion of the motor housing is not exposed to seawater, then structural integrity is maintained, but cooling effectiveness deteriorates
Solution Approach 1:
The strut acts as an intermediary heat transfer medium between the motor housing upper portion and the seawater. Heat is conducted from the motor housing through the strut walls, which then transfer the heat to the surrounding seawater, enabling cooling of areas not directly exposed to water 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 solution provides effective cooling of the hot spots with minimal space consumption and cost, maintaining a low temperature gradient around the motor housing casing, and is simple to install without requiring driving mechanisms.
Implementation Method 1
a stationary heat conducting means that is arranged in contact with the upper portion of the casing of the motor housing, which heat conducting means is arranged to conductively connect the upper portion to at least one outer wall of the strut
Implementation Method 2
embodiments including pipe-shaped elements and heat pipes for enhanced cooling
Data Source
AI summary
The invention relates to a pod propulsion device including a motor casing (3) and a strut (2), which strut (2) is connected at a lower part thereof to the motor casing (3) and is arranged to be connected at an upper part thereof to a hull (1) of a ship. The motor casing (3) includes a housing (6) enclosing an electric motor (5) with a stator and a rotor, which housing (6) has an upper portion. According to the invention a stationary heat conducting means (7) is arranged in contact with said upper portion, which heat conducting means (7) is arranged to conductively connect the upper portion to at least one outer wall (21) of the strut (2). The invention also relates to a ship provided with such pod propulsion device and to a method for cooling a pod propulsion device.