Drum Core Flange R-Edge Design for Coil Protection

The patent applies curvature by providing R surfaces at corners and ridges of flange parts to eliminate sharp edges. However, it controls the curvature radius to be 0.01 mm or more and 0.05 mm or less, creating a subtle curvature that prevents edge cutting without causing significant protrusion that would lead to handling damage.

The patent changes the parameter of curvature radius to a specific range (0.01 mm or more and 0.05 mm or less) to optimize the balance between preventing sharp edge damage and avoiding protrusion-induced handling damage. This precise parameter control resolves the contradiction between the two harmful effects.

The patent precisely controls the curvature radius parameter within the range of 0.01 mm or more and 0.05 mm or less. This parameter optimization ensures sufficient curvature to prevent sharp edge cutting while limiting protrusion magnitude to avoid significant shape deviation and handling damage.

The patent applies local quality by providing curved surfaces only at specific locations (corners and ridges of flange parts) rather than throughout the entire structure. The curvature is localized to where sharp edges would form, preventing cutting into coils while minimizing overall shape protrusion.

The patent changes the curvature radius parameter to a specific range (0.01 mm or more and 0.05 mm or less) that accounts for molding variations. This parameter selection ensures that even with molding-induced swelling, the R surface prevents sharp edge formation while the controlled curvature limits excessive protrusion.

The patent anticipates molding-induced swelling by designing R surfaces with carefully controlled curvature radii before molding occurs. The pre-calculated curvature parameters provide a buffer that absorbs molding variations, preventing both sharp edge formation and excessive protrusion despite shape inaccuracies.