Base Plate Recess Design for Disk Drive Sealing and Windage Loss
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Solution Overview
Problem
Increasing the disk diameter in disk drive devices leads to a reduction in the gap between the inner wall surface of the base plate and the disk, resulting in increased windage loss and power consumption. However, shifting the inner wall surface outward to mitigate this issue reduces the width of the base plate's upper surface, potentially compromising the sealing property between the base plate and the cover part.
Innovation Solution
The base plate design includes a support part, a bottom plate part, and a wall part with a recessed second wall part. The recess provides additional space for a seal member, ensuring adequate contact area and maintaining airtightness even when the first wall surface is shifted outward to reduce windage loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the inner wall surface of the base plate is shifted to the radially outer side to reduce windage loss, then power consumption decreases, but the width of the wall part upper surface becomes smaller, reducing sealing property
Solution Approach 1:
The invention introduces a recess structure that extends in the axial direction (vertical dimension) to provide additional sealing surface area. This allows the seal member to be positioned in the recess, creating a sealing path that utilizes the axial dimension rather than relying solely on the radial width of the wall part upper surface. The recess has a recess wall surface extending upward from the support surface, a recess top surface, and a recess support surface, creating a three-dimensional sealing configuration that compensates for the reduced radial width.
Solution Approach 2:
The seal member is nested within the recess structure of the base plate. The recess provides a dedicated space that houses the seal member, allowing it to be embedded in the base plate structure rather than merely placed on the outer surface. This nesting arrangement ensures the seal member maintains adequate contact area with the cover part while being integrated into the base plate's wall part structure.
2Productivity
If the disk diameter is increased to improve storage capacity, then productivity increases, but the gap between the inner wall surface and disk becomes smaller, increasing windage loss
Solution Approach 1:
The wall part is segmented into a first wall part and a second wall part located above it, with the recess structure providing additional segmentation in the axial direction. This segmentation allows the inner wall surface to be positioned optimally for reducing windage loss while the recess structure provides the necessary sealing functionality separately, decoupling these two functions that would otherwise conflict with each other.
3Productivity
If the width of the wall part upper surface is reduced to accommodate larger disk diameters, then storage capacity increases, but the arrangement space for the cover part becomes smaller, compromising airtightness
Solution Approach 1:
The invention transitions the sealing arrangement from a two-dimensional radial width dependency to a three-dimensional configuration utilizing the axial dimension. The recess structure with its recess wall surface, recess top surface, and recess support surface creates additional sealing space in the axial direction, allowing adequate sealing contact area to be maintained even when the radial width of the wall part upper surface is reduced to accommodate larger disk diameters.
Data Source
AI summary
A base plate includes a support part, a bottom plate part, and a wall part. The wall part includes a first wall part and a second wall part above the first wall part. The first wall part includes a first wall surface and a support surface spreading from an upper end of the first wall surface to a radially outer side. The second wall part includes a second wall surface and a recess recessed to the radially outer side from the second wall surface. The recess is defined by a space enclosed by a recess wall surface located on the radially outer side of the second wall surface and extending upward from the support surface, a recess top surface connecting from an upper end of the recess wall surface to the second wall surface, and a recess support surface facing the recess top surface in an axial direction.