Outboard Motor Cooling Pump Gearing for Independent Impeller Speed
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Solution Overview
Problem
Existing outboard motors face challenges in efficiently adjusting the rotational speed of the impeller for cooling water transport due to its direct attachment to the drive shaft, hindering optimal cooling performance.
Innovation Solution
The outboard motor incorporates a separate gear mechanism to transmit rotation from the drive shaft to the pump shaft, allowing independent control of the impeller speed, and features a non-volumetric water pump capable of operating in both forward and reverse directions, eliminating the need for a clutch mechanism and optimizing component arrangement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the impeller is directly attached to the drive shaft, then the structure is simple, but the rotational speed of the impeller cannot be adjusted according to the required amount of cooling water
Solution Approach 1:
The patent divides the transmission system into two independent gear mechanisms: one for transmitting rotation to the propeller shaft and another for transmitting rotation to the pump shaft. This segmentation allows independent control of the impeller rotational speed through the second gear mechanism while maintaining simple direct attachment structure for the propeller transmission.
Solution Approach 2:
The patent introduces a second gear mechanism as an intermediary between the drive shaft and the pump shaft. This intermediary mechanism enables adjustable rotational speed transmission to the impeller, allowing optimization of cooling water transport efficiency without complicating the overall structure.
2Ease of operation
If a clutch mechanism is used to control rotation direction, then the rotation direction can be controlled, but the space around the propeller shaft is reduced
Solution Approach 1:
The patent removes the clutch mechanism from the system by utilizing the property of non-volumetric pumps that can operate in both forward and reverse rotation directions. This extraction of the clutch mechanism provides greater space around the propeller shaft while maintaining rotation direction control capability.
Solution Approach 2:
The patent employs a non-volumetric pump that serves multiple functions: it can pump cooling water efficiently while operating in both forward and reverse rotation directions. This multi-functionality eliminates the need for separate clutch mechanisms, optimizing space utilization.
3Device complexity
If the gear ratio is fixed for both propulsion and cooling water transport, then the structure is simple, but the efficiency of cooling water transport is reduced
Solution Approach 1:
The patent segments the transmission system into two independent gear mechanisms with different gear ratios: the first gear mechanism for propulsion with an appropriate gear ratio for boat movement, and the second gear mechanism for cooling water transport with an appropriate gear ratio for efficient impeller rotation and cooling water pumping.
Solution Approach 2:
The patent changes the gear ratio parameter for the second gear mechanism to optimize cooling water transport efficiency. By adjusting the gear ratio in the second mechanism, the impeller rotational speed can be optimized for pumping cooling water, while the first gear mechanism maintains its own optimized ratio for propulsion.
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 configuration provides flexibility in setting impeller rotational speed for efficient cooling water transport, reduces motor size, and ensures reliable cooling without compromising propulsion efficiency.
Implementation Method 1
a water pump including an impeller and a pump shaft rotating together with the impeller to pump the cooling water into the cooling water flow path
Data Source
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AI summary
The outboard motor 100 includes an electric motor 120, a drive shaft 130, a propeller 141, a propeller shaft 140, a cooling water flow path 200, a water pump 210 with an impeller 211 and a pump shaft 212, a first gear mechanism 180, and a second gear mechanism 190. The first gear mechanism 180 includes a first gear 181 rotating together with the drive shaft 130 and a second gear 182 meshing with the first gear 181 and rotating together with the propeller shaft 140, wherein the second gear mechanism 190 includes a third gear 191 rotating together with the drive shaft 130 and different from the first gear 181, and a fourth gear 192 meshing with the third gear 191 and rotating together with the pump shaft 212.