Magnetic Disk Ramp Reinforcement for Thermal Stress Control

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Solution Overview

Problem

The difference in coefficients of linear expansion between resin and metal in the ramp of a magnetic disk device leads to thermal stress and potential cracking, especially at the corners, affecting the loading and unloading operations of magnetic heads due to increased size requirements with higher disk capacity.

Innovation Solution

Integrating a metal reinforcement plate with an opening in the ramp, filled with resin, to minimize the difference in relative deformation and reduce stress at the corners.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the ramp size is increased to accommodate more magnetic disks, then the storage capacity increases, but thermal stress and cracking risk increase due to greater difference in expansion between resin and metal reinforcement plate

Engineering Contradiction:

Improvenumber of magnetic disksVSAvoidcrack resistance of ramp

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The reinforcement plate is divided into multiple separate plates instead of using a single large plate. This segmentation reduces the overall area of metal in contact with resin, thereby reducing thermal stress accumulation while still providing adequate structural support for the larger ramp accommodating more magnetic disks

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Reinforcement plates are strategically positioned only in areas requiring structural support rather than covering the entire ramp surface. This localized reinforcement approach maintains structural integrity where needed while minimizing the total metal-resin interface area, thus reducing thermal stress in corner portions

Inventive Principle:

Principle #3Local quality

2Strength

If a metal reinforcement plate is embedded in the ramp, then structural strength increases, but thermal stress causes cracks in corner portions due to different coefficients of linear expansion

Engineering Contradiction:

Improvestructural strength of rampVSAvoidcrack resistance of ramp

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Metal reinforcement plates are removed from corner portions of the ramp where thermal stress concentration occurs. By extracting metal from these critical areas, the source of thermal stress is eliminated while reinforcement plates remain in other areas to maintain overall structural strength

Inventive Principle:

Principle #2Taking out (Extraction)

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 reduces the occurrence of cracks in the ramp, enhancing the reliability and stability of the magnetic disk device by minimizing thermal stress.

Implementation Method 1

resin and metal have different coefficients of linear expansion. When the ramp is subjected to temperature changes, a difference in expansion occurs between the resin-made ramp and the metal reinforcement plate, thus causing thermal stress

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS20250322845A1Ramp and magnetic disk device

Publication Date: 2025.10.16 KK TOSHIBA

AI summary

According to one embodiment, a ramp of a magnetic disk device, includes a ramp main body and a support bracket molded to be integrated as one body from resin and a metal reinforcement plate embedded in the ramp main body and opposing the support bracket. The reinforcement plate includes an opening filled with the resin and opposing a border portion between the ramp main body and the support bracket.