Outboard Engine Water Pump Input Shaft Integration
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Solution Overview
Problem
Existing outboard engine units face challenges in cooling both the engine and transmission efficiently during reverse propulsion or stop, as the water pump is typically disconnected from the output shaft, leading to increased complexity and weight due to additional components required for separate cooling systems.
Innovation Solution
The water pump is integrated onto the input shaft of the transmission, allowing continuous forward rotation and enabling cooling water to be fed to the engine during all operational states without additional components, with cooling water passages disposed around transmission gears to efficiently cool both the engine and transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the water pump is disposed separately from the output shaft of the transmission, then the water pump can be connected through a drive mechanism to an input shaft of the transmission to enable continuous cooling water feeding during reverse propulsion or stop, but the number of parts increases and hence the weight of the outboard engine unit increases
Solution Approach 1:
The water pump is merged with the input shaft assembly of the transmission by disposing it on the lower end portion of the input shaft and utilizing the input shaft's rotation to drive the water pump. This integration eliminates the need for separate drive mechanisms and additional mounting parts, thereby maintaining reliable cooling water feeding during reverse propulsion or stop while avoiding increased weight.
2Reliability
If the water pump is disposed separately from the output shaft of the transmission, then the water pump can be connected through a drive mechanism to an input shaft of the transmission to enable continuous cooling water feeding during reverse propulsion or stop, but a part for attaching the water pump separately from the output shaft or a drive mechanism is required which increases the number of parts
Solution Approach 1:
The water pump is merged with the input shaft assembly of the transmission by disposing it on the lower end portion of the input shaft and utilizing the input shaft's rotation to drive the water pump. This integration eliminates the need for separate drive mechanisms and additional mounting parts, thereby maintaining reliable cooling water feeding during reverse propulsion or stop while avoiding increased part count.
Solution Approach 2:
The input shaft serves multiple functions: it transmits rotation from the engine crankshaft to the transmission gears and simultaneously drives the water pump through its rotation. This multi-functionality allows the water pump to be driven without requiring a separate drive mechanism, reducing the number of parts while ensuring continuous cooling water feeding during all operational states.
3Reliability
If separate engine-cooling system and transmission-cooling system are included in the outboard engine unit, then both engine and transmission can be cooled, but the structure of the engine-cooling system becomes complicated and hence cost reduction becomes difficult
Solution Approach 1:
The cooling water feeding passages are integrated with the transmission gear assembly by disposing them around the transmission gears on the input shaft. This allows the same cooling water system to serve both the engine (through the water pump) and the transmission (through the passages around the gears), simplifying the overall cooling system structure while maintaining effective cooling for both components.
Solution Approach 2:
The cooling water feeding passages serve dual purposes: they deliver cooling water to the engine through the water pump and simultaneously cool the transmission gears by disposing the passages around the gears. This multi-functionality allows a single cooling water system to effectively cool both the engine and transmission, reducing structural complexity while maintaining cooling effectiveness.
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 simplifies the cooling system, reduces weight and complexity by utilizing the input shaft's rotation to drive the water pump and directs cooling water through transmission gears, ensuring efficient cooling of both the engine and transmission during all operational states.
Implementation Method 1
a water pump disposed on a lower end portion of the input shaft for drawing a cooling water from an outside of the outboard engine unit
Implementation Method 2
a plurality of cooling water feeding passages interconnecting the water pump and a cooling water inlet of the engine for directing the cooling water drawn by the water pump to the cooling water inlet, wherein the plurality of cooling water feeding passages are disposed around a plurality of transmission gears disposed on the input shaft of the transmission
Data Source
AI summary
An outboard engine unit includes a water pump disposed on a lower end portion of an input shaft of a transmission, and left and right cooling water feeding passages interconnecting the water pump and a cooling water inlet of an engine. The left and right cooling water feeding passages are disposed around a plurality of transmission gears disposed on the input shaft of the transmission. A cooling water drawn by the water pump is guided through the left and right cooling water feeding passages to the cooling water inlet.