Driveshaft

I. Core Functions of Driveshaft

1. Power transmission: The drive shaft receives the fixed-axis rotational power transmitted by the universal joint after the motion form is converted, and then smoothly transmits the torque and rotational speed to the drill bit connected at the lower end, driving the drill bit to rotate at high speed to achieve rock-breaking and drilling operations.

2. Load bearing: During drilling, it is necessary to withstand the huge axial drilling pressure transmitted by the drill bit, and at the same time, it also needs to deal with the radial deflection force and vibration load generated during the drilling process. Among them, the axial load is borne by the matching thrust bearing, while the radial load is limited by the radial bearing to limit the displacement, thereby ensuring its own stable operation.

3. Auxiliary guarantee: Some drive shafts are designed with flow diversion channels, allowing 5-10% of the drilling fluid to flow through the bearing assembly. This serves to cool and lubricate the bearings, preventing excessive wear of the bearings due to high-speed operation and frictional heat generation, and extending the overall service life of the drive shaft.

II. Typical Structural Composition of Driveshaft

The drive shaft is not a single part and is often combined with multiple matching components to form a drive shaft assembly. The overall structure is relatively regular. From the outside to the inside and the matching components usually include: the drive shaft housing, the drive shaft body inside, the upper and lower radial bearings fitted on the body, the string bearings used to bear axial loads, as well as auxiliary parts such as spacers, retaining sleeves, half rings, and water caps.

III. Common Types and Material Characteristics of Driveshaft

1. According to the sealing and lubrication methods, there are conventional mud-lubricated drive shafts and oil-sealed drive shaft assemblies. The latter seals the bearings through sealing components and injects high-temperature lubricating oil, which is suitable for more severe drilling conditions.

2. The main body of the drive shaft is mostly made of high-strength alloy steel, and its surface is often treated for wear resistance and corrosion resistance. The radial bearings that are matched are made of various materials, including hard alloy, CC alloy and other types. They can be selected according to the drilling medium and the strength of the working conditions to enhance the overall wear resistance and corrosion resistance.

IV. Precautions for Use of Driveshaft

When in use, the solid content and PH value of the drilling fluid should be controlled to avoid exceeding the tolerance range of the driveshaft and accessories. At the same time, the drilling pressure must be strictly controlled within the recommended value to prevent deformation of the driveshaft or premature failure of the bearing due to excessive load.