Head Suspension Rail Deformable Part for Vertical Rigidity
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Solution Overview
Problem
Head suspensions in hard disk drives face challenges in achieving optimal shock properties and preventing twist due to longitudinal curves in rails, which affect vertical rigidity and off-track performance.
Innovation Solution
Incorporating deformable parts at longitudinal curves of the rails on the load beam, allowing for easy deformation in both longitudinal and vertical directions, thereby improving vertical rigidity and increasing the B1 frequency to meet required shock and off-track properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the length and thickness of the load beam are reduced to improve shock property, then the weight of the load beam decreases and shock property improves, but the vertical rigidity of the load beam decreases
Solution Approach 1:
The load beam is segmented into a resilient part and a rigid part with different thicknesses. The rigid part has a greater thickness than the resilient part, creating a localized reinforcement that increases vertical rigidity without significantly increasing the overall weight or length of the load beam, thus maintaining shock property while addressing the rigidity deficiency.
2Strength
If rails are formed continuously along the side edges of the rigid part to improve vertical rigidity, then the B1 frequency increases and vertical rigidity improves, but the rails may be deformed at longitudinal curves causing twist of the head suspension
Solution Approach 1:
The rail structure transitions from continuous to discontinuous, with gaps positioned at longitudinal curves where deformation would cause twist. This local modification allows the rails to maintain vertical rigidity in straight sections while preventing stress concentration and twist at curved sections, addressing both vertical rigidity and stability concerns.
3Reliability
If the load beam is made thinner and shorter to reduce weight and improve shock property, then shock property improves, but the B1 frequency of the load beam decreases
Solution Approach 1:
The load beam is divided into resilient and rigid parts with different thicknesses. The rigid part has increased thickness which locally increases stiffness and raises the B1 frequency, while the overall reduced length and thickness of the load beam maintain improved shock property. This segmentation allows simultaneous optimization of both parameters.
Solution Approach 2:
The load beam employs a composite structure with two different thicknesses (resilient part and rigid part), creating a non-uniform cross-section that optimizes both dynamic response (B1 frequency) and shock resistance. The varying thickness profile allows the beam to exhibit different stiffness characteristics in different regions, achieving both high B1 frequency and good shock property.
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 enhances the vertical rigidity of the load beam, increases the B1 frequency, and effectively addresses the twist issue, improving the shock property and preventing off-track errors by allowing the load beam to follow arm vibrations without lifting from the disk surface.
Implementation Method 1
Each rail has a deformable part at a longitudinal curve of the rail. The deformable part is easily deformable in longitudinal and vertical directions of the rail
Implementation Method 2
the load beam to follow arm vibrations without lifting from the disk surface
Data Source
AI summary
The head suspension includes a base plate turned around a spindle, a load beam, and a flexure. The load beam includes the rigid part, a resilient part, and a head. A base end of the rigid part is attached to the resilient part, which is supported with the base plate. The head is for writing and reading data to and from a disk and is positioned at a front end of the rigid part to receive load from the load beam. The flexure is attached to the load beam and supports the head. A rail is formed along each side edge of the rigid part by bending the side edge in a thickness direction of the rigid part. The rail is continuous from the front end to the base end of the rigid part. The base end of the rigid part widens to form a wide part. The rail has a longitudinal curve around the start of the wide part. The longitudinal curve is provided with a deformable part that is more easily deformable in the longitudinal and vertical directions of the rail than the remaining parts.