The structure of the power head of the horizontal directional drill is generally driven by a high-speed motor to drive the reducer, the reducer drives the power head, and the output shaft of the reducer drives the drill rod to rotate, and the output shaft is hollow. The power head has the following functions: driving the drill bit to rotate; bearing the reaction force generated in the process of drilling and dragging; the mud enters the channel of the drill pipe.
At present, the structure of the power head of horizontal directional drills in China is basically the same, the difference is: the selection of reducer is different: the same tonnage horizontal directional drill can not choose exactly the same reducer, so the reduction ratio and performance parameters of each manufacturer are Changed. The reduction ratio of the power head is different: due to the change of the transmission ratio of the reducer, the reduction ratio of the power head also changes. At present, the transmission mode of the power head mainly includes chain transmission and gear transmission; for example, the transmission mode of the power head of the CASE drilling rig is chain transmission: the advantage of chain transmission is simple structure and easy manufacturing, but the disadvantage is poor transmission balance, short life, and output torque. small. The driving mode of the power head of the DITCH WITCH drilling rig is gear transmission; the advantages of gear transmission are balanced transmission, long service life, and large output torque; the disadvantage is that the manufacturing requires high precision.
In addition, the power head push-pull device is the actuator of the power head pull back or feed motion. Generally, a pair of low-speed high-torque motors drive a pair of reducers, the reducer drives the sprocket and chain mechanism, and the sprocket and chain mechanism provides the power head. Feed force or pull back force. The power head push-pull devices are currently different from manufacturers, such as the sprocket mechanism of DITCH WITCH; the advantages of this mechanism are fast working speed, stable work, compact structure and moderate cost. The disadvantage is that the sprocket chain is more stressed; the sprocket and chain double force mechanism of CASE company; the advantage of this mechanism is that the chain is half the force of the push and pull, and the work is stable; the disadvantage is that the working speed is slow, the structure size is large, and the cost is high; China Langfang double-cylinder mechanism. The advantage of this mechanism is that the drag force is greater than the drilling force, and the cost is lower; the disadvantage is that the structure is too large, the work stability is poor, and the service life is low, and it cannot be used for high automation requirements and self-propelled models.