Brushless Washing Machine Motor Sealing for Moisture-Proof Drive Circuits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Brushless motors in washing machines face challenges in protecting their drive circuits from moisture, particularly due to dew formation, which existing solutions struggle to address effectively, especially when high-temperature and high-pressure resin molding is involved.
Innovation Solution
A brushless motor design that incorporates a stator with windings, a rotor with magnets, and a drive circuit with a magnetic sensor, where the magnetic sensor and drive circuit are sealed within a housing using moisture-proof resin, and features like through-holes and thinner sections are used to alleviate stress from the sealing resin, ensuring the drive circuit remains undamaged during low-pressure resin injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drive circuit is sealed with molding resin at high temperature and high pressure to achieve moisture-proof structure, then moisture protection is improved, but the component or soldered section may be damaged by the resin injection
Solution Approach 1:
The sealing structure is divided into two distinct parts: a first sealing resin applied at low temperature and pressure to protect vulnerable components and soldered sections, and a second sealing resin applied at high temperature and pressure to provide comprehensive moisture protection. This segmentation allows each sealing layer to perform its specific function without causing damage to sensitive components.
Solution Approach 2:
The first sealing resin is applied to vulnerable components and soldered sections before the second sealing resin is applied. This preliminary sealing creates a protective barrier that prevents damage from the subsequent high-temperature and high-pressure resin injection, ensuring component integrity while still achieving moisture-proof protection.
2Reliability
If the drive circuit is sealed with resin to prevent dew formation and moisture, then moisture-proof structure is improved, but stress during hardening may damage the circuit
Solution Approach 1:
The sealing process is segmented into two stages with different resin materials and curing conditions. The first sealing resin is cured at low temperature and pressure, minimizing stress on the circuit board. The second sealing resin is then applied and cured at high temperature and pressure to provide robust moisture protection. This segmentation eliminates the stress damage problem while maintaining moisture-proof integrity.
Solution Approach 2:
The sealing parameters are changed between two distinct sealing operations. The first sealing uses low temperature and low pressure parameters to protect the circuit during initial sealing. The second sealing uses high temperature and high pressure parameters to achieve comprehensive moisture protection. This parameter change strategy allows the system to benefit from both low-stress and high-protection sealing characteristics.
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 provides a robust moisture-proof structure for the drive circuit, preventing damage from the sealing resin and ensuring the motor's reliability in humid environments, enhancing its durability and performance in washing machines.
Implementation Method 1
The magnetic sensor and the drive circuit are sealed with moisture-proof sealing resin
Implementation Method 2
for easing the stress produced by the sealing resin
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A brushless motor, to be used in a washing machine, includes a stator, a rotor, a magnetic sensor, and a drive circuit. The magnetic sensor and the drive circuit are accommodated in a case, and sealed with moisture-proof sealing resin, thereby forming a drive circuit unit, which is built in the brushless motor.