Timken 34478D Double Cup Tapered Roller Bearing 3" x 4.7812" x 2.0626" 34301

Description:

The Timken 34478D is a double tapered roller bearing cup (double outer ring) from the Timken 34000 Series. Designed for use with compatible Timken double cone assemblies such as the 34300 to form a complete TDO (Tapered Double Outer) bearing assembly, it provides a wide effective bearing spread for supporting heavy combined radial and axial loads while resisting overturning moments. This bearing is commonly used in industrial gearboxes, rolling mills, mining equipment, steel processing machinery, and other heavy-duty power transmission applications.

Applications:

The Timken 34478D double cup is engineered for heavy-duty applications requiring high rigidity, precise shaft alignment, and long service life. When paired with compatible Timken double cones, it is suitable for industrial gearboxes, rolling mills, mining machinery, paper mills, conveyors, and other rotating equipment subjected to high radial and thrust loads.

Technical Specifications:

• Manufacturer Part Number (MPN): 34478D
• Manufacturer: Timken
• Product Type: Double tapered roller bearing cup
• Bearing Type: Double outer ring (TDO cup component)
• Series: 34000 Series
• Design Units: Inch
• Cup Outside Diameter (OD): 4.7812 in (121.442 mm)
• Double Cup Width (C): 1.5000 in (38.100 mm)
• Compatible Cone Part Number: 34300 (also compatible with certain other 34000 Series double cones depending on application)
• Cage Material (Assembly): Stamped steel
• Bearing Material: Through-hardened bearing steel
• Maximum Housing Fillet Radius: 0.030 in (0.80 mm)
• Housing Backing Shoulder Diameter (Da): 4.60 in (116.84 mm)
• e Factor: 0.45
• K Factor: 1.30
• Y1 Factor: 1.50
• Y2 Factor: 2.23
• Geometry Factor (Cg): 0.109
• Dynamic Radial Load Rating (C90, One Row): 5,960 lbf (26.5 kN)
• Dynamic Radial Load Rating (C90, Two Row): 10,400 lbf (46.1 kN)
• Dynamic Radial Load Rating (C1, Two Row): 40,000 lbf (178 kN)
• Weight: Approximately 1.31 lb (0.59 kg)
• Function: Serves as the outer ring component of a TDO tapered roller bearing assembly for supporting heavy combined radial and axial loads.
• Features: Double-cup construction, wide bearing spread for improved rigidity, precision-ground raceways, separable design, optimized internal geometry, and long service life in demanding industrial applications.

Common Replacements:

• Timken 34478D double tapered roller bearing cup
• SKF equivalent TDO double cup (application dependent)
• NTN equivalent double tapered roller bearing cup