English 
Achieving both support and axial fixation traditionally means machining the sleeve and flange separately, then welding or clip-assembling them — more interfaces, more sources of error. A flange bushing turns both features into a single machined part, eliminating the concentricity error assembly would otherwise introduce. The sleeve body and flange are turned in one setup, with bolt holes positioned via subsequent drilling, meaning concentricity is determined by machine accuracy rather than assembly skill. Compared to a "sleeve + retaining ring" combination, a flange bushing is typically more cost-effective and far less prone to loosening over time.
