Electric Unit Cooling Fan Positioning for Motor Control
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Solution Overview
Problem
Existing electric units, such as those in lawn mowers, face challenges in effectively cooling motors and control units due to insufficient cooling air generation, especially when heat levels are high, and lack effective cooling solutions for control units in motor cooling systems.
Innovation Solution
An electric unit configuration where the control unit is positioned upstream in the cooling flow path, utilizing a cooling fan to direct cooling air to the stator after passing through the control unit, which is cooler, and incorporating a shielding unit to stabilize air flow and prevent foreign matter entry, with a coaxial cooling fan and guide walls for efficient air discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the cooling air is generated using rotation of the cutter blade, then the cooling function is provided, but the electric motor cannot be sufficiently cooled when the amount of generated heat is comparatively large
Solution Approach 1:
The cooling function is segmented into two independent systems: (1) the cutter blade rotation that generates cooling air, and (2) the cooling fan that directs cooling air specifically to the motor. This segmentation allows the motor cooling to be ensured independently of the cutter blade's cooling effect on other components.
Solution Approach 2:
A cooling fan is introduced as an intermediary device between the cooling air source and the motor. The cooling fan actively directs and concentrates the cooling air onto the motor, ensuring sufficient cooling even when the motor generates comparatively large amounts of heat.
2Device complexity
If the control unit is not specifically positioned in the cooling flow path, then the structure is simpler, but the control unit cannot be effectively cooled in relation to the motor
Solution Approach 1:
The control unit is pre-positioned on the upstream side of the cooling flow path before the motor. This preliminary positioning ensures that the control unit is the first component to receive cooling air, guaranteeing effective cooling without requiring complex additional cooling structures.
3Ease of operation
If the cooling fan is disposed on the upstream side to blow air, then the cooling air can be directed to components, but the air flow may not be smooth compared to downstream placement
Solution Approach 1:
Guide walls are introduced as intermediary structures that mediate between the cooling fan and the components. These guide walls smooth the air flow while maintaining the fan's ability to direct cooling air to specific components, resolving the conflict between directional control and flow smoothness.
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 ensures effective cooling of both the control unit and motor by stabilizing air flow and preventing foreign matter entry, enhancing cooling efficiency and reliability.
Implementation Method 1
a cooling fan configured to generate cooling air for cooling the motor and the control unit
Implementation Method 2
the cooling air generated by the cooling fan can be guided to the stator after having flowed to the control unit... Consequently, the control unit and the motor can be effectively cooled
Data Source
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AI summary
An electric unit (10A) is provided with: a motor (40) having a stator (84) and a rotor (86); a control unit (42) that controls the motor (40); and a cooling fan (44) that generates cooling wind for cooling the motor (40) and the control unit (42). The control unit (42) is provided in the upstream of the stator (84) in a cooling flow channel for circulating the cooling wind. The cooling fan (44) is provided to be positioned in the downstream of the motor (40) in the cooling flow channel, said cooling fan generating the cooling wind by drawing air.