Gimbal Suspension Profile Control for Low-Resonance HDD Assemblies
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Solution Overview
Problem
There is a need to improve the configuration of the load beam and middle struts in suspension assemblies to enhance performance and reduce overall thickness while minimizing resonance and vibrational disturbances in hard disk drives.
Innovation Solution
The suspension assembly includes a load beam with a sag bend and channels or openings in the lower surface to minimize the vertical offset between the gimbal middle struts and the load beam, maintaining a gap of 10 μm or less within 0.5 mm from the sag bend, which reduces gimbal second torsional resonance mode gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the middle struts are positioned close to the load beam to reduce overall thickness, then the effective thickness of the load beam and gimbal assembly is reduced, but the risk of contact between the middle struts and load beam increases
Solution Approach 1:
The load beam is pre-formed with sag bends during manufacturing that create predetermined clearance zones. This preliminary shaping ensures that when the gimbal assembly is assembled with middle struts positioned close to the load beam, the sag bends automatically maintain the required gap without requiring additional adjustment mechanisms or larger overall dimensions.
2Reliability
If the middle struts are positioned far from the load beam to ensure clearance, then contact prevention is achieved, but the overall thickness of the assembly increases
Solution Approach 1:
The load beam features localized sag bends at specific positions where clearance is critical, rather than uniformly increasing the overall thickness. This local deformation approach maintains the required gap between middle struts and load beam only where necessary, allowing the rest of the assembly to remain compact and minimizing the overall effective thickness.
3Volume of moving object
If the gap between middle struts and load beam is reduced to minimize thickness, then the overall dimension is reduced, but resonance gain magnitudes may increase
Solution Approach 1:
The sag bends are pre-formed in the load beam at optimized positions and angles that simultaneously achieve two objectives: maintaining minimal clearance to reduce overall thickness and positioning the middle struts to minimize resonance gain magnitudes. This preliminary geometric optimization during manufacturing ensures both compact dimensions and reduced vibrational responses without requiring trade-offs.
Data Source
AI summary
A suspension assembly having a load beam that includes a lower surface, proximal end terminating in a hinge, a distal end, and a sag bend between the proximal end and the distal end. A base plate includes a distal end connected to the hinge. A gimbal includes a base portion that includes middle struts where proximal ends of the middle struts are welded to the load beam at locations adjacent the sag bend, and a distal end welded to the distal end of the load beam. When the middle struts are positioned in a neutral position, a gap G between an upper surface of the middle struts and a plane defined by the lower surface of the load beam does not exceed 10 μm for any point along the middle struts that are within a distance D of 0.5 mm from the sag bend.