Ball Screw Cam Elevator With In-Pivot Stepper Motor for Reduced-Head HDDs
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Solution Overview
Problem
Current hard disk drives (HDDs) for active archival storage face challenges in cost-effectiveness and form factor, with traditional solutions being either too expensive or having large capital investment requirements due to unique components and assembly processes, and existing actuator mechanisms experiencing issues with loose interfaces and friction that lead to undesirable motion and wear.
Innovation Solution
A reduced-head HDD with a low-profile ball screw cam actuator elevator mechanism that uses a multi-start threaded shaft with preloaded balls to provide a stable platform for vertical translation of actuator arms, combined with a compact stepper motor and claw-pole design to efficiently access multiple disks while minimizing head count and maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional hard disk drives use multiple read-write heads for accessing multiple disks, then data access capability is improved, but cost increases and form factor enlarges
Solution Approach 1:
The patent segments the data storage system into multiple disks that can be independently accessed, with a single read-write head that moves vertically between disk surfaces. This segmentation allows the system to maintain high data access capability while reducing the number of heads required, thereby lowering cost and simplifying the overall device structure.
Solution Approach 2:
The patent introduces vertical movement of the read-write head along the Z-axis to access multiple disk surfaces, transforming the traditional planar access model into a three-dimensional access model. This dimensional change enables a single head to serve multiple disks by moving between them, reducing the need for multiple heads while maintaining productivity.
2Ease of manufacture
If actuator mechanisms use traditional interfaces without preloaded balls, then manufacturing simplicity is maintained, but friction and wear increase causing undesirable motion
Solution Approach 1:
The patent applies preloaded balls in the actuator mechanism to provide beforehand cushioning against friction and wear. The preloaded balls are positioned and pre-compressed to ensure optimal contact and load distribution before operation begins, preventing undesirable motion and wear during actual use, thereby improving reliability without significantly complicating manufacturing.
3Quantity of substance
If HDDs use extra large diameter disks or extra tall form factor, then storage capacity is improved, but capital investment and assembly complexity increase
Solution Approach 1:
The patent employs a nested arrangement where multiple disks are stacked vertically in a compact configuration, with each disk nested within the overall drive structure. This nesting approach allows high storage capacity to be achieved within a standard form factor, avoiding the need for extra large diameter disks or excessively tall form factors, thereby reducing assembly complexity and capital investment.
4Productivity
If actuator arms are moved vertically without stable platform, then access to multiple disks is enabled, but structural integrity and positioning precision deteriorate
Solution Approach 1:
The patent merges the actuator arm structure with a stable platform that includes preloaded balls and a rigid support structure. This combined structure provides both the vertical movement capability needed for multi-disk access and the structural integrity required for precise positioning, eliminating the trade-off between productivity and manufacturing precision.
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 solution reduces costs by minimizing the number of read-write heads, provides stable and precise vertical positioning, and minimizes wear and friction issues, enabling efficient access to multiple disks within a standard form factor while maintaining structural integrity and reducing operational costs.
Implementation Method 1
A reduced-head HDD with a low-profile ball screw cam actuator elevator mechanism that uses a multi-start threaded shaft with preloaded balls to provide a stable platform for vertical translation of actuator arms
Implementation Method 2
A reduced-head HDD with a low-profile ball screw cam actuator elevator mechanism that uses a multi-start threaded shaft with preloaded balls
Implementation Method 3
A reduced-head HDD with a low-profile ball screw cam actuator elevator mechanism combined with a compact stepper motor and claw-pole design
Implementation Method 4
A reduced-head HDD with a low-profile ball screw cam actuator elevator mechanism combined with a compact stepper motor and claw-pole design
Data Source
Figure 1
Figure 2A
Figure 2B~2C
AI summary
An approach to a reduced-head hard disk drive (HDD) involves an actuator subsystem that includes a ball screw cam assembly wherein the number of starts of a multi-start screw equals the number of balls riding in a corresponding start. A stepper motor may be disposed within the screw, to drive rotation of the screw, which drives translation of an actuator arm assembly so that a corresponding pair of read-write heads can access different magnetic-recording disks of a multiple-disk stack. The actuator subsystem may further include a cam locking mechanism for coupling and decoupling the actuator arm with a coil support structure and corresponding voice coil, so that the cam mechanism is able to move under the control of a voice coil motor when input/output operations are performed and is able to move the actuator arm assembly during translation operations.