【Dry Goods】Breaker Failure Analysis
Posted: Jan 9th, '25, 22:38
Friends who have used breaker hammers know that breaker hammers use hydraulically driven pistons to reciprocate and strike the drill rod as power, which plays the role of impact, hammering and stone crushing. Due to the wide range of applications and high working efficiency of breaker hammers, they are widely used in municipal, mining, metallurgy, transportation, railways, tunnels and other industries.
In the use of hydraulic breaker hammers, due to the influence of factors such as environment, operation, and components, there will be poor impact continuity, decreased impact force, insufficient impact frequency, abnormal vibration of oil pipes, hydraulic breaker hammer oil leakage and other faults. These faults will affect the performance and efficiency of hydraulic breaker hammers and increase the safety hazards of crushing operations. Therefore, the editor introduces several common breaker hammer problems for friends, so that everyone can maximize the performance of the hammer.
Breaker hammer structure
1. The drill rod breaks within a short period of use of the breaker hammer
Inspection and analysis:
When prying, the drill rod is affected by the external force F, and a huge torque (M bend) is generated at point A. Point B of the drill rod is pulled and point A is compressed. The drill rod is affected by a strong external force F, and some microcrack sources are generated at point B, and they continue to expand under the action of stress. When the bearing force at this point exceeds the tensile strength limit of the material, the drill rod will be completely broken instantly.
According to the cross section of the drill rod, it is clearly seen that the starting point of the fracture is point B, and there are obvious metal tensile cracks around it. The grains of the metal end surface are uniform and fine, and there are no small slag inclusions and hidden cracks. The grooves in the A point area are a typical reflection of the material under pressure damage.
Conclusion:
The drill rod is broken when the breaker is pried and used.
2. Abnormal wear of the drill rod (with the bushing) in a short period of time
Inspection and analysis:
When the hydraulic breaker is working, the friction between the drill rod and the bushing will generate a lot of heat. Heat can cause premature wear of the drill rod and the bushing and damage to the components. Therefore, butter should be added after 2 hours of continuous work to form an oil film to prevent dry friction and extend the service life of the drill rod and its bushing.
Conclusion:
The wear surface of the drill rod shown in the figure, lack of or no lubricating grease causes severe burns on the contact surface.
3. The drill rod stop pin broke in a short period of time
Inspection and analysis:
According to the drill rod and the broken drill rod stop pin, the upper part of the drill rod in contact with the stop pin was abnormally worn, while the lower part was almost not worn. The red contact area in the figure was worn far more than the lower part, and the drill rod was damaged at the same time, and the stop pin was broken. This shows that the last striking object in the crushing work was not stopped in time after the crushing, and the drill rod hit the drill rod stop pin many times.
Conclusion:
There are many illegal empty strikes.
4. The breaker hammer stopped striking
Inspection and analysis:
The hammer body was disassembled and checked to be intact. The reversing valve was checked and it was found that its sliding valve plug was easy to get stuck. After removing the reversing valve core, it was found that there were many traces of strain on the valve body, causing the reversing valve to get stuck during work and unable to change direction normally, causing the breaker hammer to stop working.
Main reason:
After observing the hydraulic oil remaining inside the breaker hammer, it was found that the hydraulic oil was of poor quality. The hydraulic oil flowing out of the excavator pipeline had the same problem. In addition, the inspection found that the filter element of the breaker hammer pipeline oil filter was rarely replaced, and the excavator did not regularly replace the hydraulic oil according to the specified requirements, which caused the hydraulic oil to deteriorate and directly affected the reversing valve of the breaker hammer.
Conclusion:
The reversing valve was stuck.
Other reasons:
1) Improper replacement of the bushing. After the bushing was replaced, the breaker hammer stopped working. It did not strike when pressed down, but struck when slightly lifted. After the bushing was replaced, the piston position was closer to the top, causing some small reversing valve control oil circuits in the cylinder to be closed at the starting position, and the reversing valve stopped working, causing the breaker hammer to stop working. (Replace the original or regular bushing)
2) Oil in the rear cover. (Upper cylinder body) The breaker hammer gradually became weak during the striking process and finally stopped striking. When measuring the nitrogen pressure. The pressure was too high. After the release, it could strike, but soon stopped striking again. After measurement, the pressure became high again. After disassembly, it was found that the upper cylinder body was full of hydraulic oil, and the piston could not be compressed backward, causing the breaker hammer to stop working. (Replace the sealing assembly)
The accumulator component in the pipeline fell into the pipeline. During the inspection, it was found that the deformed parts in the reversing valve stuck the reversing valve.
In addition to the above reasons, the excavator valve plate was stuck, or the O-ring on the valve plate came out of the groove, which also caused the breaker to fail to strike.
5. The breaker hammer was weak to strike
Inspection and analysis:
The breaker hammer was weak to strike, and the hose was observed to shake violently on site. The accumulator pressure of the breaker was detected, and it was found that the accumulator had no pressure and a small amount of hydraulic oil leaked out, judging that the accumulator was damaged. Remove the accumulator cover, take out the broken leather wrist, clean and dry the accumulator shell, and install a new leather wrist.
Conclusion:
The accumulator leather wrist was broken.
6. Oil leakage at the piston
Phenomenon 1
Inspection and analysis:
During the use of the breaker, a large amount of hydraulic oil leaked from the lower cylinder, and it was turbid, judging that the sealing assembly was damaged. The disassembly inspection found that there was a large amount of butter and hydraulic oil mixed between the inner sleeve and the piston, including a large amount of dirt on the piston head (see the figure above).
Conclusion:
Improper filling of grease damages the sealing component and causes oil leakage at the piston.
Correct filling method: When filling grease, the breaker should be placed vertically, and the breaker should press the drill rod tightly, that is, fill it when the drill rod is close to the piston, and fill it appropriately until the drill rod is wet with grease.
Phenomenon 2
Inspection and analysis:
The breaker leaks hydraulic oil from the lower cylinder after being stored for a period of time. After inspection, it was found that there was hydraulic oil leakage, and the breaker shell was severely rusted (upper left picture). It may be caused by the failure of moisture-proof work during storage.
After disassembly inspection, it was found that there was a trace of water rust on the piston head (upper right picture), and it was precisely because of this section of rust that the piston seal component was directly damaged and failed, causing hydraulic oil leakage.
Conclusion:
Improper storage causes piston corrosion, damages the sealing component, and causes oil leakage.
Correct storage:
For long-term storage, the gas in the nitrogen chamber must be released to allow the piston to retreat into the cylinder. See the instruction manual.
Phenomenon 3
Inspection and analysis:
A large amount of hydraulic oil leaks from the lower cylinder of the breaker during use. It was observed that there was a lot of digging during the use of the breaker. The breaker was disassembled and a large amount of small gravel was found inside the shell. After pulling out the piston, it was found that the piston and the cylinder had a large area of strain, which caused the failure of the seal component and the leakage of hydraulic oil.
Main reason:
The illegal digging operation brought a large amount of small gravel into the hammer body, and some of the gravel attached to the front end of the piston. With the reciprocating movement of the piston, it was brought into the cylinder. On the one hand, it rubbed between the piston and the cylinder, straining the piston and the cylinder, and on the other hand, it directly damaged the seal component, causing the leakage of hydraulic oil.
Conclusion:
Improper operation caused the piston to be strained, and the seal component was damaged, causing oil leakage.
7. Damage to the front end of the piston
Inspection and analysis:
Metal fragments fell from the lower cylinder of the breaker during use. The breaker was disassembled and inspected, and it was found that the striking surface of the front end of the piston was damaged (see the figure above), and the drill rod used was not damaged.
Main reason:
The hardness of the drill rod was higher than that of the piston rod, which directly damaged the piston. The drill rod itself is a consumable part, and its service life is lower than that of the piston, so the hardness is strictly controlled and mastered.
If it is too soft, the service life is too short, and if it is too hard, it will damage the piston, so it is strictly forbidden to use non-genuine drill rods in the breaker. This type of piston head is smoothed with a grinder, and it can still be used within a certain limit size. If it stops working after repair, please replace the piston.
Conclusion:
The hardness of the drill rod does not match the hardness of the piston.
Correct operation helps the efficient crushing work. If the operation is improper, the impact force cannot be fully exerted, but will rebound to the breaker body, guard plate and operating arm of the excavator body, etc., causing damage to the breaker parts. Correct operation and maintenance of hydraulic breaker can avoid some faults and make the breaker work more efficient!
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Choose BONOVO for high-quality, customizable brush cutters for skid steers with fast delivery. Contact us today to discover how our superior products can enhance your land management tasks!
for more info just visit our website at www.bonovogroup.com
contact # : +86 158 6218 2088
email : sales@bonovogroup.com
In the use of hydraulic breaker hammers, due to the influence of factors such as environment, operation, and components, there will be poor impact continuity, decreased impact force, insufficient impact frequency, abnormal vibration of oil pipes, hydraulic breaker hammer oil leakage and other faults. These faults will affect the performance and efficiency of hydraulic breaker hammers and increase the safety hazards of crushing operations. Therefore, the editor introduces several common breaker hammer problems for friends, so that everyone can maximize the performance of the hammer.
Breaker hammer structure
1. The drill rod breaks within a short period of use of the breaker hammer
Inspection and analysis:
When prying, the drill rod is affected by the external force F, and a huge torque (M bend) is generated at point A. Point B of the drill rod is pulled and point A is compressed. The drill rod is affected by a strong external force F, and some microcrack sources are generated at point B, and they continue to expand under the action of stress. When the bearing force at this point exceeds the tensile strength limit of the material, the drill rod will be completely broken instantly.
According to the cross section of the drill rod, it is clearly seen that the starting point of the fracture is point B, and there are obvious metal tensile cracks around it. The grains of the metal end surface are uniform and fine, and there are no small slag inclusions and hidden cracks. The grooves in the A point area are a typical reflection of the material under pressure damage.
Conclusion:
The drill rod is broken when the breaker is pried and used.
2. Abnormal wear of the drill rod (with the bushing) in a short period of time
Inspection and analysis:
When the hydraulic breaker is working, the friction between the drill rod and the bushing will generate a lot of heat. Heat can cause premature wear of the drill rod and the bushing and damage to the components. Therefore, butter should be added after 2 hours of continuous work to form an oil film to prevent dry friction and extend the service life of the drill rod and its bushing.
Conclusion:
The wear surface of the drill rod shown in the figure, lack of or no lubricating grease causes severe burns on the contact surface.
3. The drill rod stop pin broke in a short period of time
Inspection and analysis:
According to the drill rod and the broken drill rod stop pin, the upper part of the drill rod in contact with the stop pin was abnormally worn, while the lower part was almost not worn. The red contact area in the figure was worn far more than the lower part, and the drill rod was damaged at the same time, and the stop pin was broken. This shows that the last striking object in the crushing work was not stopped in time after the crushing, and the drill rod hit the drill rod stop pin many times.
Conclusion:
There are many illegal empty strikes.
4. The breaker hammer stopped striking
Inspection and analysis:
The hammer body was disassembled and checked to be intact. The reversing valve was checked and it was found that its sliding valve plug was easy to get stuck. After removing the reversing valve core, it was found that there were many traces of strain on the valve body, causing the reversing valve to get stuck during work and unable to change direction normally, causing the breaker hammer to stop working.
Main reason:
After observing the hydraulic oil remaining inside the breaker hammer, it was found that the hydraulic oil was of poor quality. The hydraulic oil flowing out of the excavator pipeline had the same problem. In addition, the inspection found that the filter element of the breaker hammer pipeline oil filter was rarely replaced, and the excavator did not regularly replace the hydraulic oil according to the specified requirements, which caused the hydraulic oil to deteriorate and directly affected the reversing valve of the breaker hammer.
Conclusion:
The reversing valve was stuck.
Other reasons:
1) Improper replacement of the bushing. After the bushing was replaced, the breaker hammer stopped working. It did not strike when pressed down, but struck when slightly lifted. After the bushing was replaced, the piston position was closer to the top, causing some small reversing valve control oil circuits in the cylinder to be closed at the starting position, and the reversing valve stopped working, causing the breaker hammer to stop working. (Replace the original or regular bushing)
2) Oil in the rear cover. (Upper cylinder body) The breaker hammer gradually became weak during the striking process and finally stopped striking. When measuring the nitrogen pressure. The pressure was too high. After the release, it could strike, but soon stopped striking again. After measurement, the pressure became high again. After disassembly, it was found that the upper cylinder body was full of hydraulic oil, and the piston could not be compressed backward, causing the breaker hammer to stop working. (Replace the sealing assembly)
The accumulator component in the pipeline fell into the pipeline. During the inspection, it was found that the deformed parts in the reversing valve stuck the reversing valve.
In addition to the above reasons, the excavator valve plate was stuck, or the O-ring on the valve plate came out of the groove, which also caused the breaker to fail to strike.
5. The breaker hammer was weak to strike
Inspection and analysis:
The breaker hammer was weak to strike, and the hose was observed to shake violently on site. The accumulator pressure of the breaker was detected, and it was found that the accumulator had no pressure and a small amount of hydraulic oil leaked out, judging that the accumulator was damaged. Remove the accumulator cover, take out the broken leather wrist, clean and dry the accumulator shell, and install a new leather wrist.
Conclusion:
The accumulator leather wrist was broken.
6. Oil leakage at the piston
Phenomenon 1
Inspection and analysis:
During the use of the breaker, a large amount of hydraulic oil leaked from the lower cylinder, and it was turbid, judging that the sealing assembly was damaged. The disassembly inspection found that there was a large amount of butter and hydraulic oil mixed between the inner sleeve and the piston, including a large amount of dirt on the piston head (see the figure above).
Conclusion:
Improper filling of grease damages the sealing component and causes oil leakage at the piston.
Correct filling method: When filling grease, the breaker should be placed vertically, and the breaker should press the drill rod tightly, that is, fill it when the drill rod is close to the piston, and fill it appropriately until the drill rod is wet with grease.
Phenomenon 2
Inspection and analysis:
The breaker leaks hydraulic oil from the lower cylinder after being stored for a period of time. After inspection, it was found that there was hydraulic oil leakage, and the breaker shell was severely rusted (upper left picture). It may be caused by the failure of moisture-proof work during storage.
After disassembly inspection, it was found that there was a trace of water rust on the piston head (upper right picture), and it was precisely because of this section of rust that the piston seal component was directly damaged and failed, causing hydraulic oil leakage.
Conclusion:
Improper storage causes piston corrosion, damages the sealing component, and causes oil leakage.
Correct storage:
For long-term storage, the gas in the nitrogen chamber must be released to allow the piston to retreat into the cylinder. See the instruction manual.
Phenomenon 3
Inspection and analysis:
A large amount of hydraulic oil leaks from the lower cylinder of the breaker during use. It was observed that there was a lot of digging during the use of the breaker. The breaker was disassembled and a large amount of small gravel was found inside the shell. After pulling out the piston, it was found that the piston and the cylinder had a large area of strain, which caused the failure of the seal component and the leakage of hydraulic oil.
Main reason:
The illegal digging operation brought a large amount of small gravel into the hammer body, and some of the gravel attached to the front end of the piston. With the reciprocating movement of the piston, it was brought into the cylinder. On the one hand, it rubbed between the piston and the cylinder, straining the piston and the cylinder, and on the other hand, it directly damaged the seal component, causing the leakage of hydraulic oil.
Conclusion:
Improper operation caused the piston to be strained, and the seal component was damaged, causing oil leakage.
7. Damage to the front end of the piston
Inspection and analysis:
Metal fragments fell from the lower cylinder of the breaker during use. The breaker was disassembled and inspected, and it was found that the striking surface of the front end of the piston was damaged (see the figure above), and the drill rod used was not damaged.
Main reason:
The hardness of the drill rod was higher than that of the piston rod, which directly damaged the piston. The drill rod itself is a consumable part, and its service life is lower than that of the piston, so the hardness is strictly controlled and mastered.
If it is too soft, the service life is too short, and if it is too hard, it will damage the piston, so it is strictly forbidden to use non-genuine drill rods in the breaker. This type of piston head is smoothed with a grinder, and it can still be used within a certain limit size. If it stops working after repair, please replace the piston.
Conclusion:
The hardness of the drill rod does not match the hardness of the piston.
Correct operation helps the efficient crushing work. If the operation is improper, the impact force cannot be fully exerted, but will rebound to the breaker body, guard plate and operating arm of the excavator body, etc., causing damage to the breaker parts. Correct operation and maintenance of hydraulic breaker can avoid some faults and make the breaker work more efficient!
Mini crawler excavator，Mini crawler excavator attachments，Excavator attachments，Crawler excavator，Mini excavator purchase
Choose BONOVO for high-quality, customizable brush cutters for skid steers with fast delivery. Contact us today to discover how our superior products can enhance your land management tasks!
for more info just visit our website at www.bonovogroup.com
contact # : +86 158 6218 2088
email : sales@bonovogroup.com