Analysis and prevention of shank adapter fracture of hydraulic rock drill


The shank adapter is the core component of a hydraulic rock drill that transmits rotational force and impact force. It must withstand complex loads transmitted by the impact piston and rotary motor during operation. Abnormal fracture of the shank adapter is a typical failure, which often occurs in less than 10 shifts of operation, and the fracture location is mostly at the root or thread of the thread.


 shank adapter

Failure analysis of abnormal fracture of shank adapter




The impact force generated by the rock drill during operation may cause the bolts connecting it to the mounting plate to gradually loosen, causing the rock drill to swing during operation.




If the wear of the inner hole of the shank adapter guide sleeve exceeds the standard value and is not replaced in time, this will cause the gap between the rock drill and the guide bush to increase, which will cause the front end of the shank adapter to shake during work.




Insufficient lubrication of the rock drill prevents the shank tail from being effectively cooled and lubricated during rock drilling, resulting in excessive temperature of the shank tail and a decrease in strength.




The propulsion pressure of the rock drill does not match the impact pressure, causing the rock drill to hit empty, and the shank adapter bears a large undue impact load.




The rock drill was not installed correctly on the pusher beam, causing the center line of the shank adapter to be out of axis with the hole centers of the front end and the middle holder, causing the shank adapter to be subject to additional radial force.


Preventive measures for abnormal breakage of shank adapter




Before starting each shift, check the air lubricating oil spray condition of the machine head and observe whether the oil film on the shank adapter is uniform. Only after it meets the lubrication requirements can the machine be started for drilling.




Check the connection between the rock drill mounting bolts and the rock drill mounting base every 40 working hours. It should be ensured that the bolt torque is normal and the center of the shank adapter is coaxial with the front end and the middle anchor hole center.




During drilling operations, the propulsion pressure of the rock drill should be adjusted in time according to changes in rock hardness. For rocks with higher hardness, the propulsion pressure should be reduced, and for rocks with lower hardness, the propulsion pressure should be increased to prevent empty drilling.




Regularly check the inner diameter of the solder tail guide sleeve and replace the solder tail guide sleeve every 800 impact hours to prevent the solder tail from swinging due to excessive wear of the guide sleeve inner diameter.

rock drill

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