Staggered Tolerance Ring for Pivot Bearing Torque Ripple
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Solution Overview
Problem
State-of-the-art tolerance rings in disk drives experience high torque ripple on the actuator pivot bearing, which affects the rotational performance and increases energy costs due to the configuration of contacting portions and ball bearings.
Innovation Solution
A tolerance ring with staggered contacting portions arranged in multiple rows around the cylinder, where each row is circumferentially displaced by a specific distance to distribute forces evenly and reduce torque ripple, thereby improving the rotational performance of the pivot bearing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If contacting portions are arranged in a conventional configuration on the tolerance ring, then the structural simplicity is maintained, but high torque ripple occurs on the pivot bearing
Solution Approach 1:
The contacting portions are arranged in an asymmetric staggered pattern around the cylindrical surface of the tolerance ring. Specifically, the contacting portions are positioned at different angular intervals in different axial regions, creating an asymmetric distribution that balances the radial forces on the pivot bearing. This asymmetric arrangement reduces torque ripple and improves rotational performance while maintaining structural simplicity.
2Weight of moving object
If the actuator arm is made from aluminum or aluminum alloy to reduce weight, then the weight is reduced, but the material becomes softer and more easily scratched
Solution Approach 1:
The tolerance ring is constructed as a composite structure with a cylindrical base portion and raised contacting portions. The contacting portions are made from a material that is harder and more scratch-resistant than the actuator arm material (aluminum or aluminum alloy), while the base portion can be made from a softer, more compliant material. This composite construction allows the lightweight aluminum actuator arm to maintain its weight advantage while the harder contacting portions provide the necessary scratch resistance and structural integrity at the interface.
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 staggered configuration of contacting portions on the tolerance ring minimizes torque ripple, enhancing the rotational performance of the pivot bearing and reducing energy costs associated with disk drive operation.
Implementation Method 1
A tolerance ring with staggered contacting portions arranged in multiple rows around the cylinder, where each row is circumferentially displaced by a specific distance to distribute forces evenly and reduce torque ripple
Data Source
AI summary
A tolerance ring configured to reduce torque ripple for a pivot bearing in an actuator arm assembly. The tolerance ring comprises a cylinder having a predetermined length, and a first and a second row of contacting portions arranged around the surface of the cylinder, the contacting portions of the second row are circumferentially displaced with respect to the first row by a distance greater than zero but less than the distance of the contacting portion and the spacing between adjacent contacting portions in the first row.