Transmission System of Oil Drilling Equipment
The transmission system performs the functions of power transfer, distribution, and speed regulation, delivering the prime power from the power units with precision to the drawworks, rotary table, mud pumps, top drive, and other working equipment, achieving power matching and adaptation to operating conditions.
It mainly comprises couplings, gearboxes, drive shafts, chain transmission mechanisms, hydraulic transmission modules, and variable-frequency transmission modules. Mechanically driven rigs use chains, gears, and gearboxes as the core to achieve staged transfer of mechanical power; electrically driven variable-frequency rigs rely mainly on electrical transmission, realizing stepless speed regulation through frequency control, with smoother power transfer, higher speed-regulation accuracy, and lower failure rates, precisely matching different drilling load requirements.
When ordering please specify:of Oil Drilling Equipment
- Kelly type (square or hexagonal);
- nominal size and overall length;
- Upper and lower connections.
| Nom Size (in) | Standard O.D.(in) | Bottom Connection‑Hex. O.D.(in) | I.D.(in) | Drive Section(in) |
| | Standard O.D.(in) | Optional O.D.(in) | Square O.D.(in) | Hex. O.D.(in) | Square | Hex. | A | B |
| 2 1/2 | 6 5/8 REG LH 7 3/4 | 4 1/2 REG LH 5 3/4 | NC26 3 3/8 | | | 1 1/4 | 3 1/4 | |
| 3 | 6 5/8 REG LH 7 3/4 | 4 1/2 REG LH 5 3/4 | NC31 4 1/8 | NC26 3 3/8 | 1 3/4 | 1 1/4 | 3 3/8 | 3 3/8 |
| 3 1/2 | 6 5/8 REG LH 7 3/4 | 4 1/2 REG LH 5 3/4 | NC38 4 3/4 | NC31 4 1/8 | 2 1/4 | 1 3/4 | 4 7/16 | 3 15/16 |
| 4 1/4 | 6 5/8 REG LH 7 3/4 | 4 1/2 REG LH 5 3/4 | NC46 6 1/4 | NC38 4 3/4 | 2 13/16 | 2 1/4 | 5 1/2 | 4 25/32 |
| 4 1/4 | 6 5/8 REG LH 7 3/4 | 4 1/2 REG LH 5 3/4 | NC50 6 3/8 | NC38 4 3/4 | 2 13/16 | 2 1/4 | 5 1/2 | 4 25/32 |
| 5 1/4 | 6 5/8 REG LH 7 3/4 | | 5 1/2 FH 7 | NC46 6 1/4 | 3 1/4 | 3 | 6 3/4 | 5 29/32 |
| 5 1/4 | 6 5/8 REG LH 7 3/4 | | NC56 7 | NC50 6 3/8 | 3 1/4 | 3 1/4 | 6 3/4 | 5 29/32 |
| 6 | 6 5/8 REG LH 7 3/4 | | | 5 1/2 FH 7 | | 3 1/2 | | 6 13/16 |
| 6 | 6 5/8 REG LH 7 3/4 | | | NC56 7 | | 3 1/2 | | 6 13/16 |
