Power Unit Axial Size Reduction via Single Cooling Fan
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Solution Overview
Problem
The existing power unit design, with cooling fans fixed to both ends of the crankshaft, results in an enlarged axial size due to the need for separate fans for the transmission chamber and radiator, which is inefficient in terms of space utilization.
Innovation Solution
Incorporating an air guide passage in the crankcase that directs the airflow from the cooling fan to both the transmission chamber and radiator, eliminating the need for separate cooling fans on the crankshaft, and utilizing air guide walls to distribute airflow efficiently, thereby reducing the axial size of the power unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate cooling fans are attached to both ends of the crankshaft for cooling the transmission chamber and radiator, then cooling function is ensured, but the axial size of the power unit is enlarged
Solution Approach 1:
The patent merges the functions of two separate cooling fans (one for transmission chamber cooling and one for radiator cooling) into a single cooling fan. This single fan is positioned at one end of the crankshaft and uses air guide passages to direct airflow to both the transmission chamber and radiator, thereby reducing the axial size while maintaining both cooling functions
Solution Approach 2:
The patent introduces air guide passages as intermediary structures that channel airflow from the single cooling fan to multiple target areas (transmission chamber and radiator). These air guide passages act as mediators that distribute the cooling airflow efficiently to different components that would otherwise require separate fans
2Length of moving object
If a single cooling fan is used with air guide passages, then the axial size is reduced, but the complexity of airflow distribution increases
Solution Approach 1:
The patent segments the airflow path by providing separate air guide passages for different cooling zones (transmission chamber and radiator). Each passage is independently configured to direct airflow to its specific target, simplifying the overall control while managing the complexity through structured segmentation of the airflow distribution system
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 allows for efficient airflow distribution to both the transmission chamber and radiator, enhancing cooling efficiency and reducing the overall size of the power unit in the axial direction without increasing its size, as the airflow is directed through the radiator core, improving cooling efficiency.
Implementation Method 1
a cooling fan which is fixed to a crankshaft and generates an air flow in response to a rotation of the crankshaft
Implementation Method 2
the air flow passes through the radiator which exchanges coolant water with the engine body
Data Source
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AI summary
[SUBJECT] To provide a power unit reduced in size in an axial direction of a crankshaft. [MEANS FOR SOLUTION] A power unit includes a radiator 58 that is disposed at a position facing one end of a crankshaft 45 protruding from a first case half 33a, and connected to a water jacket 52b by a pipe, a belt type continuously variable transmission that includes a belt 63 wound on a driving pulley 59 attached to a crankshaft 45 projecting from a second case half 33b, a transmission case that is connected to a crankcase 33 and forms a transmission chamber 68 accommodating the belt 63, a cooling fan 97 that is fixed to the crankshaft 45 and generates an air flow in response to the rotation of the crankshaft 45, a first guide path 99a that guides the air flow of the cooling fan 97 toward the belt 63 in the transmission chamber 68, and a second guide path 99b that guides the air flow of the cooling fan 97 which passes through the radiator 58.