Marine Propulsion Unit Casing for Motor Controller Cooling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional marine propulsion units face challenges in reducing size and complexity of wiring, with existing solutions either increasing the size of the propulsion unit or requiring complex wiring when the motor ECU is positioned inside the vessel or steering shaft.
Innovation Solution
A marine propulsion unit design featuring a casing separate from the steering shaft that houses the motor controller, allowing for reduced wiring length and size increase, with the casing extending along the propeller's rotation axis to minimize water resistance and facilitate cooling, while being steerable with the duct to prevent interference and water intrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the motor ECU is disposed inside the steering shaft, then the wiring length is reduced, but the diameter of the steering shaft must be increased, causing the overall size of the marine propulsion unit to increase
Solution Approach 1:
The patent divides the control system into two separate housing locations: the motor controller is placed in the casing (skeg) while the drive unit remains in the steering shaft. This segmentation allows each component to be optimally positioned without compromising the other, reducing wiring length while avoiding increasing the steering shaft diameter.
Solution Approach 2:
The motor controller is relocated from the radial direction (inside the steering shaft) to the axial direction (in the casing extending along the rotation axis). This dimensional change allows the controller to be positioned close to the driven portion without requiring an increase in the steering shaft's cross-sectional dimensions.
2Volume of moving object
If the motor ECU is disposed inside the marine vessel, then space is available, but the wiring becomes complex and lengthened
Solution Approach 1:
The motor controller is extracted from the marine vessel and integrated into the casing of the propulsion unit itself. This extraction eliminates the need for long wiring runs through the vessel and reduces wiring complexity by localizing the control system within the propulsion assembly.
3Length of stationary object
If the casing is provided to house the motor controller, then wiring length is reduced, but water resistance may increase
Solution Approach 1:
The casing is designed to serve multiple functions: it houses the motor controller, provides structural support, and acts as a skeg for hydrodynamic stability. By integrating these functions into a single component, the design avoids adding separate elements that would increase water resistance.
Solution Approach 2:
The casing is configured to be steerable together with the duct, allowing it to dynamically adjust its position relative to the water flow. This dynamic capability reduces the casing's impact on water resistance by optimizing its orientation during operation.
4Object-affected harmful factors
If the casing extends along the rotation axis, then water resistance is reduced, but the motor controller housing space is constrained
Solution Approach 1:
The motor controller is nested within the casing structure, utilizing the internal space of the skeg. This nesting approach allows the controller to be housed in the casing without requiring additional external volume, maintaining the streamlined axial configuration while providing adequate housing space.
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 design effectively reduces the size and complexity of wiring while maintaining efficient propulsion and cooling of the motor controller, improving steering performance and reducing water resistance, even when the motor controller size increases.
Implementation Method 1
The casing can be disposed in the water, and thus it is possible to efficiently cool the motor controller disposed in the casing
Implementation Method 2
The casing extends along the rotation axis of the propeller such that it is possible to significantly reduce or prevent an increase in water resistance, and thus even when the casing is provided, a marine vessel can be propelled without problems
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
This marine propulsion unit (100) includes a duct (1) including a stator (11), a propeller (2) including a rim (21) including a rotor (23) disposed at a position that faces the stator and a blade (22) provided radially inward of the rim, a steering shaft (3) that supports the duct such that the duct is steerable, a casing (4) provided separately from the steering shaft and that extends along a rotation axis A of the propeller, and a motor controller (5) disposed in the casing and that controls rotational driving of the propeller.