55TAC03D bearings ( 55 mm x 120 mm x 29 mm) have the advantages of High axial stiffness and load-bearing capacity, 60° contact angle design, pre-installed and pre-loaded for easy installation, optional sealing for maintenance-free operation, and are therefore widely used in the Machine tool ball screws, machining centers, automated equipment, robots, precision measuring devices.

| Part Number | 55TAC03D |
| Bearing Type | Angular Contact Super Precision Thrust Ball Bearings, TAC 03 Series for Ball Screw Support (High-Load Drive) |
| Internal design | D = Contact angle 55 ° |
| Contact angle - α | 55 ° |
| Type | TAC |
| Dimension series | 03 = 03 Series |
| Preload | M = Medium preload |
| Bearing Mass - m [lb] | 3.1746 |
| DB/DF Arrangement H preload [lbf] | 952 |
| DB/DF Arrangement H Axial Rigidity | 1013 N/µm |
| DB/DF Arrangement H Starting Torque | 0.68 N・m |
| DB/DF Arrangement H Measured Axial Clearance | -24 µm |
| Speed ratings (grease) - nB | 3379 min–1 |
| Speed ratings (oil) - nG | 4282 min–1 |
| Recommended Grease Quantities - CC | 32 g/brg |
| Dimension | |
| d φ Inside [inch] | 2.1654 |
| D Φ Outside [inch] | 4.7244 |
| B Width [inch] | 1.1417 |
| r min Chamfer [inch] | 0.0787 |
| r1 min Chamfer [inch] | 0.0394 |
| d1 Shoulder [inch] | 2.6772 |
| d2 Shoulder [inch] | 3.4016 |
| D1 Shoulder/Recess [inch] | 3.5512 |
| D2 Shoulder/Recess [inch] | 4.3189 |
| Dynamic Axial Capacity | |
| Ca 1 row [lbf] | 42651 |
| Ca 2 row [lbf] | 69661 |
| Ca 3 row [lbf] | 92107 |
| Ca 4 row [lbf] | 112356 |
| Ca 5 row [lbf] | 131453 |
| Static Axial Capacity | |
| C0a 1 row [lbf] | 47164 |
| C0a 2 row [lbf] | 94345 |
| C0a 3 row [lbf] | 141533 |
| C0a 4 row [lbf] | 188803 |
| C0a 5 row [lbf] | 235997 |
| Other Arrangement | 1 rows: DB(<>); DF(><) 2 rows: DT(<<); DFD(><<); DFF(>><<); DBD(<<>); DBB(<<>>) 3 rows: DFT(><<<); DFFD(>><<); DFFF(>>><<<); DBT(<<<>); DBBD(<<<>>); DBBB(<<<>>>) 4 rows: DFTD(><<<<); DFFT(>><<<<); DBTD(<<<<>); DBBT(<<<<>>) 5 rows: DFTT(><<<<<); DBTT(<<<<<>) |
The 55TAC03D Ball screw support bearings are typically composed of high-precision angular contact ball bearings paired back-to-back (DB) or in series (DT) configurations. They feature a small contact angle (15° or 20°) and high-rigidity cages (phenolic resin or brass) on both inner and outer rings, achieving a precision grade of P4 or higher. Some models integrate seals and lubrication holes, forming a preload unit.
Ball screw support bearings offer extremely high axial rigidity and load-bearing capacity, accurately withstanding bidirectional axial loads in screw drives. The back-to-back configuration provides anti-overturning moment capability, ensuring positioning accuracy. The preload design eliminates axial backlash, achieving backlash-free, low-friction operation with low heat generation, making them suitable for high-speed feed. They are factory-installed and ready to use, simplifying installation and adjustment.















