Common faults and troubleshooting methods of air hammers

Common Faults and Troubleshooting methods of Air Hammers

When air hammers are under high-load impact conditions for a long time, problems such as component wear and seal failure are quite common. Mastering the corresponding troubleshooting and repair methods can significantly reduce the downtime of the equipment and ensure the continuity of production.

1. The hammer head does not rise to sufficient height and the strike is weak

Cause of fault ‌ : the position of the air filler hole is misaligned, resulting in insufficient air replenishment; the inner wall of the cylinder is worn and leaks air; the piston expansion ring is broken or the clearance is too large; the fit clearance of the rotary valve is excessive; the seal of the check valve is failed and the spring is broken; the friction force of the hammer rod movement is abnormally increased.

Troubleshooting method ‌ : Open the cover to check the alignment of the filling hole and the piston hole, and adjust it to the designed standard position; Carry out boring or bushing repair on the inner walls of cylinders with wear exceeding grade 7 precision. Replace the broken piston expansion ring and adjust the lap clearance to the specified range. Grind the worn rotary valve to ensure that the fit clearance meets the factory requirements. Replace the poorly sealed check valve and the failed spring. Correct the skewed guide sleeve of the working cylinder, adjust the fit clearance between the hammer rod and the guide sleeve, and troubleshoot and repair the problem of upsetting and deformation of the hammer rod.

2. The hammer rod piston strikes the upper cover of the working cylinder

Cause of fault ‌ : The nut of the working cylinder head is loose or the sealing gasket is damaged and leaks air; the steel ball check valve is not tightly engaged or the steel ball is broken; the plug cover on the top surface of the piston is loose and leaks air; there are sand holes and air holes on the top surface of the hammer rod piston causing air leakage; the height from the upper airway to the cylinder top is insufficient.

Troubleshooting method ‌ : Tighten the cylinder head nut and replace the aged and damaged gasket; Replace the worn and broken steel balls and the matching springs; After the loose plug cover and the hammer rod hole are fitted with interference fit, they are riveted flat and fixed. Repair the sand holes and gas holes on the top surface of the piston by welding. Install a suitable gasket on the top of the working cylinder to raise it and make up for the height of the air passage.

3. The speed of lifting the hammer is too slow

Cause of fault ‌ : The cylinder block is not sealed tightly, and compressed air flows up and down through the piston gap, resulting in insufficient pressure difference between the upper and lower chambers of the working cylinder.

Troubleshooting method ‌ : According to the groove size of the compressed sealing ring, turn two sealing grooves on the cylinder, install the appropriate sealing ring to block the gas transmission channel, and restore the sealing performance of the cylinder block.

4. Abnormal noises occur in the compression cylinder

Cause of fault ‌ : Loose or broken lead fastening screws of the compression cylinder, loose crankshaft bearing housing, excessive clearance between the connecting rod shaft and the copper sleeve, loose connecting rod shaft pin.

Troubleshooting method ‌ : Replace the broken fastening screw and tighten it to the specified torque; Recalibrate the crankshaft axis and tighten the loose bearing housing. Replace the worn copper sleeve and adjust the fit clearance between the connecting rod shaft and the copper sleeve to the standard range. Tighten the loose connecting rod shaft pin and install anti-retraction pins to prevent it from shifting again.

5. After the equipment is started, the control handle is heavy and inflexible

The cause of the ‌ fault is ‌ : the rotation is flexible when not started, but the pulling resistance increases sharply after loading. This is mostly due to unbalanced air pressure in the valve train and insufficient lubrication of the rotary valve.

Troubleshooting method ‌ : Clear the lubricating oil passage of the rotary valve and add the specified grade of lubricating oil; Adjust the air distribution gap of the upper and lower rotary valves to ensure balanced air pressure on both sides and eliminate the additional resistance of handle operation.

6. There is air or oil leakage at the lower flange of the hammer rod

Cause of fault ‌ : The sealing ring is damaged and fails, the tension spring of the sealing block of the hammer rod sleeve is broken, and the hammer rod is unevenly worn with severe scratch marks.

Troubleshooting method ‌ : replace the seal block with a brand new one; Replace the broken tension spring to ensure that the clamping force of the sealing block meets the standard. Repair the scratches on the surface of the hammer rod by grinding with an oilstone or through mechanical processing to restore the surface smoothness.

7. The bolts fixing the hammer rod sleeve are loose or broken

Cause of fault ‌ : the nut is loose, resulting in uneven force on the bolt; the gasket between the rod sleeve and the working cylinder is damaged; after multiple repairs on the upper and lower anvils, the stroke of the forging hammer is too large, and the working piston collides with the lower forging.

Troubleshooting method ‌ : Regularly inspect all nuts to ensure they are all tightened; Replace the damaged gasket to ensure that all bolts are evenly stressed. Check the distance from the contact surfaces of the upper and lower anvils to the lower flange. If it exceeds the design requirements, replace it with a new anvil block to prevent the piston from directly hitting the workpiece.