Motor Stator Wall Portion Blocks Coating Agent Flow
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Solution Overview
Problem
The application of a coating agent to a printed circuit board in conventional motors can lead to position accuracy issues of the motor shaft due to the coating agent flowing into the stator core, causing inclination or eccentricity of the shaft during assembly.
Innovation Solution
The design includes a stator core with an insulator and a wall portion that protrudes radially outward, contacting the circuit board's inner surface and opposing the solder portion, with a wider circumferential width than the solder portion, preventing the coating agent from flowing into the stator core's insertion hole and maintaining the shaft's position accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating agent is applied to the printed circuit board for moisture prevention, then the circuit board is protected from moisture, but the coating agent flows into the stator core through the insertion hole causing shaft position accuracy to deteriorate
Solution Approach 1:
A seal member is introduced as an intermediary component between the printed circuit board and the stator core. This seal member fills the insertion hole and prevents the coating agent from flowing into the stator core, while allowing the circuit board to maintain its moisture protection function. The seal member acts as a mediator that blocks the harmful flow path without interfering with the beneficial moisture prevention function.
Solution Approach 2:
The insertion hole is segmented into two functional zones: an upper portion that allows passage of the shaft and bearing housing, and a lower portion that is filled with the seal member to block coating agent flow. This segmentation enables the insertion hole to serve dual purposes: mechanical assembly pathway and protective barrier against coating agent infiltration.
2Reliability
If the coating agent adheres to the radially inner surface of the stator core, then the coating agent provides moisture protection, but the adhesion causes inclination or eccentricity of the shaft
Solution Approach 1:
The seal member serves as a physical barrier that prevents direct contact between the coating agent and the radially inner surface of the stator core. By blocking the flow path at the insertion hole, the seal member ensures that the coating agent remains confined to the printed circuit board surface and cannot migrate to critical areas where it would cause shaft misalignment.
Data Source
AI summary
A motor includes a stationary portion, a rotating portion, and a bearing portion. The rotating portion includes a shaft that rotates about a central axis extending vertically. The stationary portion includes a bearing housing, a stator, and a circuit board. The circuit board is above the stator and includes an insertion hole that permits insertion of the bearing housing. The stator includes a stator core, an insulator, a coil, and a terminal pin. The terminal pin is connected to a conductive wire and connected to the circuit board via a solder portion covered with a coating layer. The insulator includes a base portion and a wall portion. The wall portion protrudes upward from the base portion, is radially outward of the bearing housing, and contacts a radially inner surface of the circuit board at the insertion hole.