Disk Drive Motor Journal Bearing Span Optimization
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Solution Overview
Problem
Current disk drive designs face challenges in maximizing angular stiffness while maintaining a compact form factor, as the length of the journal bearing span is limited by the axial space occupied by the hub/shaft interface and thrust plate, which restricts the separation of upper and lower journal bearings.
Innovation Solution
The solution involves relocating the hub/shaft interface from the axial ends to a more centered position along the shaft, thereby increasing the journal bearing span by positioning the thrust plate between the upper and lower journal bearings, and using a single or dual thrust bearing to enhance mechanical damping and angular stiffness without increasing motor height or axial space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the hub/shaft interface is positioned at the axial ends to simplify structure, then the device complexity is reduced, but the journal bearing span length is limited
Solution Approach 1:
The hub/shaft interface is repositioned from the axial ends to a centered position along the shaft axis, effectively utilizing the axial dimension to maximize the journal bearing span. This dimensional repositioning allows the upper and lower journal bearings to be separated by a greater distance while keeping the thrust plate within the available axial space, thereby increasing the journal bearing span without requiring additional radial or lateral dimensions.
Solution Approach 2:
Instead of positioning the hub/shaft interface at the axial ends as in conventional designs, the invention inverts this arrangement by placing it at the center of the shaft. This inversion allows the journal bearings to be positioned at the axial ends, maximizing the span between them while the thrust plate occupies the central region, thus resolving the space conflict.
2Stability of the object's composition
If the journal bearing span is increased to improve angular stiffness, then the angular stiffness is improved, but the motor height increases
Solution Approach 1:
The design maximizes the utilization of the axial dimension to increase the journal bearing span, thereby improving angular stiffness without increasing the radial dimensions that would contribute to motor height. By positioning the hub/shaft interface centrally and the journal bearings at the axial extremes, the span is optimized within the existing height constraints.
3Stability of the object's composition
If the thrust plate is positioned to maximize journal bearing span, then the angular stiffness is improved, but the axial space utilization becomes constrained
Solution Approach 1:
The design efficiently packs the thrust plate and hub/shaft interface into the central axial region, allowing the journal bearings to extend to the axial ends. This arrangement maximizes the journal bearing span while maintaining compact axial dimensions, as the thrust plate occupies the central space rather than extending the overall axial length.
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 configuration increases angular stiffness and mechanical damping, allowing for a longer journal bearing span while maintaining a compact design, thereby improving the stability and performance of the fluid dynamic bearing motor in disk drives.
Implementation Method 1
upper journal bearing and a lower journal bearing. The upper journal bearing and the lower journal bearing are defined in a gap between the stationary component and the rotatable component
Implementation Method 2
A thrust bearing is disposed between the upper journal bearing and the lower journal bearing
Data Source
AI summary
Provided herein, is an apparatus that includes a stationary component, a rotatable component, and an upper journal bearing and a lower journal bearing. The upper journal bearing and the lower journal bearing are defined in a gap between the stationary component and the rotatable component, and the stationary component and rotatable component are configured for relative rotation. A thrust bearing is disposed between the upper journal bearing and the lower journal bearing.