Spindle Motor Adhesive Bonding for Rigidity and Vibration Control
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Solution Overview
Problem
In spindle motors, insecure fixation of rotating portions leads to reduced rigidity, increased vibration, and potential deformation, causing errors in disk reading and writing.
Innovation Solution
A motor design with a cylindrical magnet and yoke, where the first radial gap is filled with adhesive for secure fixation, and the second radial gap is adhesive-free to prevent deformation, enhancing rigidity and reducing vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive is applied over a large area to fix the rotor hub and rotor yoke, then the fixation strength is improved, but the rotor hub deformation increases
Solution Approach 1:
The patent applies adhesive only to specific local areas (the upper end and axial middle portion of the first radial gap) rather than over the entire surface. This localized application provides sufficient fixation strength while avoiding excessive adhesive contact that would cause rotor hub deformation during curing.
2Stability of the object's composition
If adhesive is applied to fix various portions of the rotating portion, then the rigidity is improved, but the vibration increases due to deformation
Solution Approach 1:
By applying adhesive only to specific locations (first radial gap at upper end and axial middle portion) rather than uniformly across all interfaces, the patent achieves sufficient rigidity enhancement while preventing the deformation that would generate vibration.
Solution Approach 2:
The patent uses partial adhesive application (only in specific gaps and regions) rather than complete coverage. This partial action provides the necessary fixation and rigidity improvement without the harmful effects of excessive adhesive application.
3Strength
If the rotor hub and rotor yoke are fixed through adhesion, then the assembly strength is improved, but the curing process causes deformation
Solution Approach 1:
The patent restricts adhesive application to specific local areas (first radial gap at upper end and axial middle portion) rather than the entire contact surface. This localized approach provides adequate assembly strength while minimizing the deformation caused by adhesive curing.
Solution Approach 2:
The patent divides the adhesive application into separate segments (first radial gap and second radial gap with different adhesive arrangements). This segmentation allows optimization of each region's adhesive application to achieve strength without deformation.
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 design improves the rigidity of the motor, reduces vibration, and minimizes deformation, thereby enhancing the accuracy of disk reading and writing operations.
Implementation Method 1
A first radial gap has a greater radial width at a lower end than at an upper end, the first radial gap being a radial gap between an outer circumferential surface of the magnet and an inner circumferential surface of the yoke cylindrical portion. The first radial gap includes a tapered gap gradually increasing in radial width with decreasing height from an upper end thereof. The upper end of the tapered gap is located above an axial middle of the first radial gap. The first radial gap is filled with an adhesive from at least the upper end to the axial middle thereof.
Data Source
AI summary
A rotating portion of a motor includes a magnet, a yoke including a yoke cylindrical portion, and a hub including a hub cylindrical portion. A first radial gap, which is a radial gap between the magnet and the yoke cylindrical portion, is filled with an adhesive from an upper axial end to an axial middle portion thereof, and includes a tapered gap gradually increasing in radial width with decreasing height. An upper axial end of the tapered gap is located above the axial middle portion of the first radial gap. In addition, no adhesive is provided from a lower axial end to an axial middle portion of a second radial gap, which is a radial gap between the yoke cylindrical portion and the hub cylindrical portion.