Propeller-Shaft-Driven Water Pump Layout in Outboard Motors
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Solution Overview
Problem
The installation position of the water pump in outboard motors is restricted due to its attachment to the drive shaft, limiting design flexibility and requiring additional space for components like a clutch mechanism.
Innovation Solution
The water pump is driven by the rotation of the propeller shaft, allowing it to be installed near the propeller shaft where there is more space, eliminating the need for a clutch mechanism and enabling a more flexible design. This configuration includes a non-volumetric pump and a joint member with spline connections for efficient rotation and assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the water pump is attached to the drive shaft, then the water pump can be driven by the drive shaft rotation, but the installation position is restricted and design flexibility is reduced
Solution Approach 1:
The patent introduces a pump shaft as an intermediary component that is driven by the propeller shaft through a joint member. This mediator allows the water pump to be positioned independently from the drive shaft, enabling flexible installation near the propeller shaft while still receiving rotational drive power, thus resolving the contradiction between adaptability and device complexity
Solution Approach 2:
The patent segments the drive system into separate components: the drive shaft for power generation, the propeller shaft for propulsion, and the pump shaft for water pumping. This segmentation allows each component to be independently positioned and optimized, with the pump shaft detachably connected to the propeller shaft, thereby increasing design flexibility without compromising the driving function
2Adaptability or versatility
If a clutch mechanism is added to enable reverse rotation, then the drive shaft can rotate in both directions, but the space around the propeller shaft is reduced
Solution Approach 1:
The patent makes the drive shaft universally capable of rotating in both forward and reverse directions directly, eliminating the need for a separate clutch mechanism. The drive shaft's bidirectional rotation capability is transmitted to the propeller shaft, providing multi-functionality without occupying additional space around the propeller shaft, thus resolving the contradiction between adaptability and area
3Ease of repair
If the pump shaft is detachably connected to the propeller shaft, then maintenance is facilitated, but the connection structure becomes more complex
Solution Approach 1:
The patent segments the connection between the pump shaft and propeller shaft into detachable coupling portions, allowing the pump shaft to be separated from the propeller shaft for maintenance. The coupling portions use standardized spline connections that are simple in structure but effective in function, enabling easy assembly and disassembly without overly complicating the connection structure, thus resolving the contradiction between ease of repair and device complexity
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 increases design flexibility, optimizes the arrangement of components, and simplifies the manufacturing process by allowing the water pump to be installed in a more spacious area, reducing the overall size of the outboard motor while facilitating maintenance and reducing load on the pump shaft.
Implementation Method 1
a water pump that pumps the cooling water into the cooling water flow path, wherein the water pump includes an impeller and a pump shaft that rotates together with the impeller
Data Source
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AI summary
The outboard motor 100 includes an electric motor 120, the drive shaft 130 rotationally driven by the electric motor 120, the propeller 141, the propeller shaft 140 rotating together with the propeller 141, the gear mechanism 180 that transmits rotation of the drive shaft 130 to the propeller shaft 140, the cooling water flow path 200 through which cooling water flows, and the water pump 210 that pumps the cooling water into the cooling water flow path 200, wherein the water pump 210 includes an impeller 211 and a pump shaft 212 that rotates together with the impeller 211, and the pump shaft 212 is arranged to be coaxial with the propeller shaft 140 and connected so as to rotate together with the propeller shaft 140.