Wiper Motor Segmented Housing for Dust Protection
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Solution Overview
Problem
Conventional wiper motors with speed reduction mechanisms face issues with dust and grease accumulation on the circuit board due to the proximity of the speed reduction mechanism, leading to reduced heat dissipation, malfunction, and decreased detection accuracy, necessitating frequent maintenance.
Innovation Solution
A brushless motor design where the speed reduction mechanism and control board are positioned on opposite ends of the rotating shaft, with a sensor magnet and MR sensor detecting rotational states, preventing dust and grease from reaching the control board and enhancing precision and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the circuit board is arranged in the gear housing to cover the speed reduction mechanism, then the control board can be compactly integrated, but dust and grease from the meshing portion are easily attached to the circuit board
Solution Approach 1:
The patent divides the housing into two separate compartments: a gear housing for the speed reduction mechanism and a control board housing for the circuit board. This segmentation physically separates the circuit board from the dust-generating meshing portion, eliminating the contamination problem while maintaining compact integration through the connected housing structure.
Solution Approach 2:
The circuit board is extracted from the gear housing and placed in a separate control board housing. This extraction removes the circuit board from the harmful environment of dust and grease generated by the speed reduction mechanism, while the two housings remain connected to maintain overall system compactness.
2Loss of energy
If the circuit board is covered with extraneous matters, then heat dissipation is reduced, but this leads to malfunction and lowered detection accuracy
Solution Approach 1:
By segmenting the housing into separate gear and control board compartments, the circuit board is protected from dust and grease accumulation. This prevents the formation of heat-insulating layers on the circuit board, maintaining effective heat dissipation and ensuring reliable operation of circuit elements and magnetic sensors.
3Reliability
If maintenance is performed frequently to prevent malfunction, then reliability can be maintained, but productivity is reduced
Solution Approach 1:
The segmented housing design with separate compartments prevents dust and grease from reaching the circuit board, eliminating the need for frequent maintenance. The speed reduction mechanism is enclosed in its own housing, containing contaminants within that compartment while protecting the control board housing from contamination.
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 design effectively prevents dust and grease from reaching the control board, improving heat dissipation, reducing maintenance needs, and enabling precise control of the rotating shaft over a long period while maintaining high reliability.
Implementation Method 1
coils wound around teeth of the stator; and a motor case part formed into a cylinder shape; each coil generates an electromagnetic force for rotating the rotating shaft
Implementation Method 2
a sensor magnet fixed to the other end portion of the rotating shaft; and a rotation sensor provided to a portion of the control board facing the sensor magnet and detecting a rotational state of the rotating shaft
Data Source
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AI summary
In a wiper motor including a motor unit having a rotating shaft, and a gear unit having a speed reduction mechanism for reducing and outputting the speed-reduced rotation, a first speed reduction gear forming a speed reduction mechanism is provided to one end side of a rotating shaft, a sensor magnet is fixed to the other end side of the rotating shaft, a control board is provided so as to face the other end side of the rotating shaft from the axial direction of the rotating shaft, a MR sensor for detecting a rotational state of the rotating shaft is provided to a facing portion of the control board to the sensor magnet, and coil end portions of coils configured to generate an electromagnetic force for rotating the rotating shaft on the basis of supply of drive current from the control board is electrically connected to the control board.