Spindle Motor Hub Structure for High-Capacity HDD Vibration Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional hard disk drives (HDDs) face challenges in achieving resistance to external impact and maintaining vibration characteristics due to design constraints on height dimension, especially with increasing HDD capacity, making it difficult to incorporate a sufficient number of magnetic disks without compromising structural integrity.
Innovation Solution
The HDD design incorporates a shaft-rotating spindle motor with specific thickness ratios (h2/h1 ≥ 1.89) for the hub flange and base, allowing for a larger number of magnetic disks while ensuring impact resistance and vibration stability, using a simpler mechanism compared to shaft-fixed motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base thickness is increased to achieve impact resistance, then vibration characteristics improve, but the height dimension increases which conflicts with design constraints
Solution Approach 1:
The invention applies local quality by concentrating thickness in specific critical areas rather than uniformly throughout the base. The first thickness portion and second thickness portion are strategically positioned to provide localized reinforcement where impact forces are most severe, while other areas maintain reduced thickness to control overall height.
Solution Approach 2:
The base is segmented into multiple thickness portions (first thickness portion and second thickness portion) with different thickness values. This segmentation allows the structure to optimize impact resistance in specific zones while maintaining overall compact dimensions, resolving the contradiction between local strength requirements and global size constraints.
2Reliability
If a shaft-fixed spindle motor is used to improve impact resistance, then vibration characteristics improve, but device complexity and cost increase
Solution Approach 1:
Instead of fixing the shaft and rotating the armature (conventional shaft-fixed motor), the invention inverts the approach by fixing the armature and rotating the shaft (shaft-rotating motor). This inversion simplifies the motor structure while the thickened base portions compensate for vibration, achieving impact resistance through structural design rather than complex motor mechanics.
Solution Approach 2:
The invention extracts the vibration damping function from the motor structure itself and transfers it to the base structure. By removing the need for complex shaft-fixed motor mechanisms and placing thickness enhancement in the base, the solution separates motor simplicity from vibration control, achieving both goals independently.
3Quantity of substance
If the number of magnetic disks is increased to achieve higher capacity, then storage capacity improves, but vibration characteristics and impact resistance deteriorate
Solution Approach 1:
The invention addresses the vibration problem by transitioning from a two-dimensional planar base to a three-dimensional structure with varying thickness portions. The vertical dimension (thickness) is introduced to provide additional stiffness and damping capacity, enabling the system to support more disks without compromising vibration resistance.
Solution Approach 2:
The base functions as a composite structure with different thickness portions effectively creating zones of different structural properties. The thicker portions provide enhanced stiffness and damping to counteract the increased vibration from multiple disks, while thinner portions maintain overall weight and size efficiency.
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
The design achieves impact resistance and vibration stability with a 30% cost reduction, enabling a larger disk capacity and stable operation with five or more magnetic disks, meeting or exceeding industry standards for impact and vibration performance.
Implementation Method 1
The spindle motor includes a stator and an armature. The armature includes a yoke, a magnet, and a hub
Data Source
AI summary
A magnetic disk device according to one embodiment includes a base, five or more magnetic disks in the base, a head actuator, and a spindle motor. The base has a bottom wall having a second thickness and a side wall. The spindle motor includes a sleeve with a first hole, fixed to the bottom wall, a shaft inserted in the first hole rotatably, and a hub rotatable integrally with the shaft. The hub includes a first part, a second part extending from a lowermost surface of the first part in a first direction being from the magnetic disks toward the bottom wall, and a third part having a first thickness and extending from a lowermost surface of the second part in a second direction orthogonal to the first direction. A value obtained by dividing the second thickness by the first thickness is greater than or equal to 1.89.