Spindle Motor Through Hole Sealability via Capillary Segmentation
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Solution Overview
Problem
Conventional spindle motors face issues with sealability due to bubble generation and incomplete filling of sealing materials in the through hole, leading to potential gas leakage in disk drive devices.
Innovation Solution
The spindle motor design incorporates a through hole with a columnar lower and upper column body, where the upper column body has a smaller cross-sectional area than the lower, utilizing capillary phenomenon to ensure complete filling and prevent bubble formation, thereby enhancing sealability and preventing gas leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sealing material is filled in the through hole, then the through hole is sealed, but bubbles may be generated in the sealing material and deteriorate the sealability
Solution Approach 1:
The through hole is divided into a lower column body and an upper column body with different cross-sectional areas. This segmentation allows the sealing material to be filled from the lower wide portion first, then progress to the upper narrow portion, preventing bubble entrapment and ensuring complete filling.
Solution Approach 2:
Different portions of the through hole have different cross-sectional areas - the lower column body has a larger cross-sectional area while the upper column body has a smaller cross-sectional area. This local variation in geometry optimizes the sealing material filling process and prevents bubble formation.
2Reliability
If sealing material is filled in the through hole, then the through hole is sealed, but the sealing material may not be filled up to the end of the through hole and deteriorate the sealability
Solution Approach 1:
The through hole is divided into a lower column body and an upper column body with different cross-sectional areas. This segmentation creates a flow path that guides the sealing material from the lower wide portion to the upper narrow portion, ensuring complete filling to the end of the through hole.
Solution Approach 2:
The cross-sectional area parameter of the through hole is changed along its length, with the lower column body having a larger area and the upper column body having a smaller area. This parameter variation ensures proper filling of the sealing material and prevents incomplete sealing.
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 ensures reliable sealing by preventing incomplete filling and bubble generation, maintaining the integrity of the helium gas within the housing and improving manufacturing efficiency.
Implementation Method 1
utilizing capillary phenomenon to ensure complete filling and prevent bubble formation
Data Source
AI summary
A spindle motor includes a base, a shaft arranged on the base and extending in a vertical direction, a stator having a coil defined by a wound conductive wire and arranged on an upper surface of the base, and a rotor rotatably supported around the shaft. The base has a through hole that penetrates the base from the upper surface to a lower surface. The conductive wire is drawn out to the lower surface side through the inside of the through hole. The through hole is sealed by a sealing material. The through hole includes a columnar lower column body and a columnar upper column body. The lower column body is arranged on the lower surface side of the base. A cross-sectional area of the upper column body orthogonal to an axial direction is smaller than a cross-sectional area of the lower column body orthogonal to the axial direction.