Integral Drive Unit for Vessel Propulsion
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Solution Overview
Problem
The existing vessel propulsion devices face difficulties in inserting or removing a stator packet when an electric motor is used, due to the streamlined housing design, which requires high forces and poses risks of damage and water ingress, and they can only be tested after assembly, leading to potential mechanical stress and reduced lifespan.
Innovation Solution
A releasable integral drive unit is used, allowing the drive unit to be slid into a recess without significant force, with a compact and accurately manufactured design that includes a non-electrically conductive liquid for cooling and lubrication, preventing water ingress and reducing mechanical stress through resilient mounting means and direct electric motor driving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the housing is designed with a streamlined droplet form to reduce water resistance, then the housing can move through water with low resistance, but the stator packet cannot be easily inserted or removed due to the countersunk design and limited opening access
Solution Approach 1:
The housing is divided into two separable parts: a streamlined outer housing that reduces water resistance and an inner stator housing that can be independently accessed. This segmentation allows the stator packet to be installed and removed through the drive shaft opening without compromising the streamlined external form, resolving the contradiction between aerodynamic efficiency and maintenance accessibility.
Solution Approach 2:
The stator housing is nested within the streamlined outer housing, with the stator packet positioned inside the stator housing. This nested structure allows the stator to be accessed through the drive shaft opening while maintaining the compact, streamlined external shape, enabling easy stator replacement without sacrificing hydrodynamic performance.
2Ease of operation
If high forces are applied to insert or remove the stator packet from the streamlined housing, then the stator can be installed, but damage to the housing or stator packet may occur
Solution Approach 1:
The stator housing is extracted as a separate, independently accessible component from the streamlined outer housing. The stator can be installed and removed through the drive shaft opening without applying high forces to the main housing structure, eliminating the risk of damage while maintaining ease of operation.
3Power
If the electric motor is placed in an air chamber in the housing, then the motor can operate, but water may ingress into the housing causing short-circuiting and oxidation
Solution Approach 1:
A sealed stator housing acts as an intermediary barrier between the electric motor and the external water environment. This intermediate structure provides IP68 protection, preventing water ingress while allowing the motor to operate in its designated air chamber, thus maintaining both power output and reliability.
4Stability of the object's composition
If the stator packet is arranged countersunk inside the housing to remain stationary, then the stator is fixed in place, but the housing must be heated to high temperature for expansion to insert or remove the stator
Solution Approach 1:
The housing is segmented into an outer streamlined section and an inner stator housing section. The stator is fixed within the stator housing through precise mechanical positioning features, eliminating the need for thermal expansion methods. This segmentation allows the stator to be installed and removed through the drive shaft opening at ambient temperature, resolving the contradiction between stable positioning and ease of installation.
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 enhances the efficiency and reliability of the propulsion device by allowing extensive testing before assembly, reducing mechanical stress, preventing water ingress, and extending the lifespan through efficient cooling and lubrication, while maintaining compactness and power density.
Implementation Method 1
with a compact and accurately manufactured design that includes a non-electrically conductive liquid for cooling and lubrication
Implementation Method 2
includes a non-electrically conductive liquid for cooling and lubrication
Implementation Method 3
reducing mechanical stress through resilient mounting means
Data Source
Figure 1
Figure 2A~2B
Figure 3A
AI summary
The present invention relates to a vessel propulsion device comprising a propeller which is connected to a drive shaft, characterized in that the vessel propulsion device further comprises an integral drive unit to be arranged releasably in a housing of the vessel propulsion device and comprising an electric motor which is configured to drive the drive shaft, wherein the electric motor is provided with a rotor, which can be coupled to the drive shaft, and a stator, and wherein the drive unit is filled with an electrically insulating liquid.