Disk Drive Suspension Dimple-Protrusion Positioning
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Solution Overview
Problem
The existing disk drive suspensions face challenges in accurately positioning sliders and dimples, leading to reduced gimbal motion range and potential electrical connection failures due to poor positional accuracy, especially in miniature designs where dimple size and recess ratio affect bond strength and tilt.
Innovation Solution
A disk drive suspension design featuring a small dimple on the tongue portion with a protrusion on the load beam, where the dimple's height is less than the protrusion's, allowing accurate positioning and maintaining a sufficient gimbal motion range without interference, and ensuring precise alignment of the slider and dimple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the dimple size is reduced to improve positioning accuracy and reduce recess ratio, then the allowed range of gimbal motion is reduced due to interference with the load beam
Solution Approach 1:
A protrusion is introduced as an intermediary element on the load beam that contacts the dimple tip. This mediator allows the dimple to be smaller for better positioning accuracy while the protrusion provides the necessary support and clearance to maintain gimbal motion range, preventing direct interference between the small dimple and the load beam structure.
2Measurement precision
If the dimple is formed on the tongue portion to improve positioning accuracy, then the recess on the reverse side causes slider tilt or reduced bond strength in miniature designs
Solution Approach 1:
The invention applies local quality by making the dimple asymmetric with different characteristics on each side. The tip side has a smaller area to reduce the recess ratio and prevent slider tilt, while the base side maintains sufficient structure for bonding. This localized differentiation allows the dimple to serve dual purposes: positioning accuracy and bond strength maintenance.
3Ease of manufacture
If laser welding is used to secure the flexure to the load beam, then the mounting position can be regulated with limited accuracy, causing worsening positional accuracy between dimple and slider
Solution Approach 1:
The dimple and protrusion are pre-formed on the tongue portion and load beam respectively, establishing a precise mechanical reference before assembly. This preliminary action creates a self-aligning feature that compensates for the limited accuracy of laser welding, ensuring accurate positioning between the slider and dimple even when the flexure mounting has some variation.
Data Source
AI summary
A disk drive suspension is provided with a load beam and a flexure. A tongue portion is formed on the flexure. The tongue portion comprises a slider mounting surface and a flat portion. A slider is mounted on the slider mounting surface. A dimple is formed on the flat portion. A tip of the dimple projects thicknesswise relative to the tongue portion toward the load beam. A protrusion is formed on a facing surface of the load beam. An end face of the protrusion projects thicknesswise relative to the load beam toward the dimple. As the tip of the dimple contacts the end face of the protrusion, the tongue portion is swingably supported on the protrusion.