Common fault causes and treatment methods of broken hammer
Time：2016-08-05 14:58:51 Form：admin
Question 1. The production of black oil?
cause:
The black oil that causes the hydraulic system of the excavator is not only caused by dust, but also caused by the irregularity of the filling of the butter.
For example, when the distance between the bushing and the steel brazing is more than 8 mm (the little finger can be inserted), it is recommended to replace the bushing. On average, one upper bushing needs to be replaced for every two lower bushings.
When replacing hydraulic fittings such as oil pipes, steel pipes, and oil return filters, it is necessary to clean the dust or debris at the interface before releasing them.
When adding butter, you need to lift the breaker and press the steel into the piston. You only need to add half of the standard grease gun for each filling. (Because if the steel is not pressed when the grease is added, the butter will be placed at the upper limit of the steel groove. When the steel is working, the butter will directly hit the main seal of the breaker. The reciprocating motion of the piston brings the butter into the cylinder of the breaker, and then the hydraulic oil in the cylinder of the breaker is mixed into the hydraulic system of the excavator, which is the deterioration of the hydraulic oil, blackening)
Approach:
1. Use the buttery posture correctly.
2. Install a return oil filter unit.
3. Install a water spray device to reduce external dust.
4. The upper and lower bushings are worn too much and the bushing is replaced at the appropriate time.
5. The intake check valve is broken or blocked, and the check valve is checked regularly.
6. Replace the dust seal in time.
7. Use the breaker correctly (do not always hit).
8. Note that the steel size matches the bushing.
Question 2. Is the breaker hammer weak?
cause:
There is no strength for the hammer. There are many reasons, such as insufficient nitrogen pressure, insufficient oil pressure in the pipeline, and so on. It was also related to the local weather and the hardness of the ore at the time.
Approach:
1. First check that the pressure of nitrogen is not enough.
2. Check that the static oil pressure is not enough.
3. Check if the working oil is sufficient.
4. The size of the steel and the guard screws are loose.
5. Bushing clearance and wear condition.
6. Test if the hydraulic fluid is sufficient.
7. The shutoff valve is not fully open.
8. The relief valve lock nut is loose.
All of the above are normal:
(1) The pilot A port has insufficient pressure or a spare valve card, and there is a large amount of diarrhea.
(2) The main oil or oil return blockage.
(3) The piston or control valve has a large amount of bleed.
(4) Insufficient power source or large pump diarrhea
If it is a broken hammer with an accumulator, check if the accumulator's cup is broken.
Question 3. The broken hammer leaks oil?
cause:
There are also many reasons for the oil leakage of the broken hammer, which is divided into different parts.
Approach:
1. Oil leakage at the piston:
(1) Observing its daily maintenance mode, the bulk disintegration inspection, a large amount of hydraulic oil leaking and turbid, and a large mixture of butter and hydraulic oil mixed between the tail bushing and the piston.
This is caused by improper filling of the butter. Replace the seal assembly in time and explain to the customer the correct way to butter.
(2) It was found that hydraulic oil leaked and the hammer shell was severely corroded. Because the customer does not use it for a long time, the storage method is wrong, causing water erosion, the rust directly causes the strain damage of the piston seal, which causes oil leakage, and explains to the customer, the way of long-term preservation: the nitrogen is released, and the steel is pressed Go in, the upper end of the upper cylinder is higher than the lower part.
(3) Observing the operation mode, there is a large amount of planing and digging action, so that a large amount of small debris is brought into the casing, causing wear of the piston seal and oil leakage. Explain to the customer the correct way to prevent this from happening again.
2. Oil leakage between the nitrogen chamber and the middle cylinder joint:
The "O" ring of the seam between the nitrogen chamber and the middle cylinder is worn.
3. Oil leakage at the base of the reversing valve and the middle cylinder: The "o" ring of the reversing valve base is damaged.
4. The connection surface of the middle cylinder and the oil pipe interface:
Cause: The O-ring seal is worn or the tubing body interface is loose.
Replace the O-ring and tighten to the specified torque.
5. The oil leakage between the middle cylinder and the upper cylinder: the O-ring and the seal ring are worn and strained, and the hammer body is loose.
Replace the O-ring seal ring and the reinforcement ring in time, and stipulate the tightening torque.
9. Oil leakage at the junction between the control valve box and the control valve cover:
The O-ring is worn and the control bonnet screws are loose.
Replace the O-ring and tighten the torque.
In addition to the above reasons, the oil seal is aging, the hydraulic oil is dirty, causing strain, the bushing gap is too large, the beating, the oil film is destroyed, etc., and the oil leakage is likely to occur.
Question 4. Broken hammer bolts often break?
cause:
Due to the harsh working environment of the breaker, its parts are easy to wear. It is normal for the bolts to break frequently. In addition, when the breaker is working, it will generate strong vibration force, which will result in the guard bolts and When the through bolt is loose, the thread at the thread of the bolt is often subjected to fatigue damage and eventually causes breakage. The specific reasons are as follows:
The guard plate is deformed.
Desoldering at the weld, causing deformation.
The quality problem itself is not strong enough.
Single force, uneven force. (no regular inspection)
Caused by external forces.
The pressure is too large and the vibration is too large.
Caused by improper operation such as empty play.
Processing method:
Tighten the bolts every 20 hours.
Standardize the operation mode, and do as little as possible to do the planing and digging.
Question 5. What are the disadvantages of empty play on the breaker?
cause:
Irregular operation, when the broken hammer is in the air, the piston transmits the impact force to the steel brazing, and the steel brazing transfers the impact force to the steel brazing pin, and the steel brazing pin is easy to break when subjected to a strong impact force. When the steel brazing pin is impacted, the impact force is dispersed to the transverse pin of the steel brazing pin before and after the impact. At this time, the cross pin of the steel brazing pin will smash the inner hole of the cross pin of the top steel pin, thereby causing cracking of the crotch block at the edge of the inner hole. Finally, the lower cylinder is broken.
Frequent air play will cause cracks in front bodies, flat pins, bolts, etc., cracks on guards, booms, steel brazing, hoses, and hard pipes.
Treatment method: crushing the ore after crushing the ore, the impact angle is 85 degrees - 95 degrees.
Explain to the customer that the operation is in accordance with the instructions on the instructions of the breaker.
Question 6. Does the breaker stop hitting?
cause:
There are also many reasons for not hitting:
For example: stop the blow during the work of the breaker:
Reversing valve card. After the disintegration inspection of the breaker, it was found that the other was intact. When the reversing valve was inspected, it was easier to issue the slippery hairpin. After removing the spool of the reversing valve, it was found that there were many strains on the valve body. (replace the reversing valve spool)
Improper replacement of the bushing. After the breaker is replaced, the failure of the work stops, the press does not strike, and there is a blow after a slight lift. Since the position of the piston is more upsided after the bushing is replaced, some small reversing valve control oil passages in the cylinder are closed at the starting position, and the reversing valve stops working, causing the breaker to stop working. (replace original or regular bushing)
The back cover is filled with oil. (Upper cylinder) The breaker is gradually weak during the strike and finally stops. The nitrogen pressure is measured. The pressure is too high, after the release, it can be hit, and soon the blow is stopped, and the pressure becomes higher after the measurement. After disintegration, it was found that the upper cylinder was filled with hydraulic oil, and the piston could not be compressed backwards, causing the breaker to fail to work. (change seal assembly)
The accumulator part in the line falls into the line. 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 is stuck, or the O-ring on the valve plate comes out of the groove, which also causes the breaker to not hit.
Question 7. Can the breaker hammer frequency be adjusted?
cause:
Check the breaker frequency regulator, check the deformation and damage of each O-ring after removing the frequency adjustment, and the frequency cannot be changed.
Approach:
Replace the regulator O-ring.
Question 8. Does the new hammer does not hit?
cause:
It may be that the pipeline is reversed. The pipeline should be high pressure on one side of the cab and low pressure on one side. Actually, the reverse installation causes the breaker to not work.
It can also be that the valve on the excavator multi-way valve is stuck.
The high and low hoses are not installed correctly. The cab is high on one side and low on the side.
Approach:
Install the tubing correctly.
Make sure the valve is working properly.
Question 9. Is the front end of the piston broken?
cause:
The broken hammer will fall off the metal fragments during use, and the debris will fall after the front cover. After the removal, it was found that the striking surface of the front end of the piston was damaged, and the steel brazing used for the broken hammer was inspected for the user's own. The hardness is too high. When the hardness is higher than the hardness of the piston, the front end of the piston wears faster during the operation.
Approach:
1. Correct the piston head with a sander, but within a certain limit.
Explain to customers the purchase of genuine parts. (steel brazing rod - drill rod)
Question 10. How to judge the breakage of the broken hammer steel? Is it a quality problem?
Approach:
There are two situations in which the steel is broken:
fracture
(1) The section of the fracture is mainly the grain of the steel brazing.
As shown in the figure, this is an informal operation
It is also the most common type of steel fracture surface. This is mainly due to the undercut, the steel brazing, the wear of the inner sleeve, the angle of the drill rod is not normal, and the tortuous stress causes the steel to break. We do not include this broken steel brazing.
(2) Fracture position
This kind of fracture has no obvious trauma to the surface of the steel brazing, and the broken section is uneven, and there are fragments in the opposite direction at the beginning of the damage.
(3) Location of the starting point of the fracture
Tail broken
(1) The location of the bad face
(2) the size of the face
If it is not used for a long time, the iron rod should be rust-proofed, and the rusted rod heat treatment layer will be broken, which will cause fatigue damage.
Lever type operation, fatigue damage, corrosion
The above types are not covered by the warranty.
Within the scope of the warranty, the failure caused by defects in the internal material is warranted. The material penetrates into the foreign matter during the manufacturing process, cracking from the inside, and the ripple is different at the edge. The section is uneven and the water ripples are inside the starting point.
Question 11. Why should I warm up before using the breaker? (East Air)
cause:
This is determined by the characteristics of the East Air Hammer itself. The East Air Hammer has a large impact force and a high frequency, which is much faster than other hammer wear seal components, so the warming machine can slow down the process of oil seal wear. ·
When the hydraulic oil is in a static state, the solid oil film adheres between the piston and the oil seal. The hammer warmer is to let the moist hydraulic oil wash the relatively solid hydraulic oil film, and establish a new hydraulic oil film to open the oil seal to ensure that the oil seal is opened. Pistons and oil seals do not cause strain damage at the beginning.
When the hammer starts to work, it is in a cold state. Suddenly, the hot oil, thermal expansion and contraction will cause no small damage to the oil seal. With the fast frequency movement, it will be easier to produce oil leakage and frequent oil seal replacement. phenomenon. Therefore, using the hammer to warm up the machine, whether it is for the customer or us, the advantages outweigh the disadvantages.
Approach:
Patiently explain the benefits of warming up with customers: prevent oil leakage, extend the life of the damaged parts of the broken hammer, and benefit the excavator itself, and prove the warm-up benefits to the customer with practical examples in life: the car is also warm when used. The reason for the machine is self-evident.
Warm-up procedure: the hammer is vertically off the ground, and the foot pedal is about 1∕3, and the main inlet pipe is slightly shaken (close to the tubing on the side of the cab), and the foot stroke is kept for 20-40 minutes. .
Question 12. What is the gap between the replacement guide sleeves? What happens if you don't change it in time?
Approach:
Generally it is about eight millimeters (the little finger can reach into the lower cylinder).
If it is not replaced in time, the following consequences will occur:
(1) The gap between the steel brazing and the bushing is too large. In the crushing operation, dust, foreign matter and the like may enter the cylinder body. As the steel brazing reciprocates, the wear and tear seals the sealing assembly, causing oil leakage, black oil and the like.
(2) Because the gap is too large, there will be a unilateral force, which will damage the oil film and cause the piston of the middle cylinder to be strained.
(3) During the striking process, the plane of the steel tail and the plane of the striking end of the piston cannot be in contact with the surface, which eventually leads to the destruction of the steel tail.
(4) When the piston can't move up and down vertically, it will eccentrically grind the cylinder, causing the cylinder to quickly lose its roundness. When the roundness is too large, internal leakage will occur inside the breaker, and the impact force of the breaker will be reduced.
(5) Reduce the service life of the piston and steel.
Question 13. What is the oil pressure of the breaker working normally, and what effect does the oil pressure have on the breaker and the excavator?
Approach:
For new excavators, it is generally between 200-220, and for old excavators it is generally 230 or more.
If the oil pressure is too low, the strength during the crushing process will be small.
If it is too high, the strength of the blow is very large, but the wear of the hydraulic pump and the hammer itself will be very serious: the weld of the hammer, the boom, the pressure plate and the like are cracked at the weld. Bolts are prone to breakage, hoses, hard tubes leaking oil, and the performance of the excavator and breaker is degraded early.
Question 14. What are the reasons for the leak?
cause:
(1) The gas seal oil seal is damaged, or there is a quality problem in itself.
(2) The spool is damaged.
(3) There is a crack in the upper cylinder.
(4) Normal loss.
Processing method:
1. Check the nitrogen valve stone for damage. Soak the soapy water around the nitrogen valve, fill it with nitrogen, and observe the surrounding and inflated air bubbles.
2. Nitrogen chamber O-ring damage: Apply soapy water to the position where the middle cylinder and nitrogen chamber are connected. If there is air bubble, replace the two air seals.
3. There is air bubble in the inlet and outlet, which proves that the O-ring of the outer ring of the piston ring is damaged and needs to be replaced.
4. The breaker leaks during operation, indicating that the gas seal inside the piston ring is damaged and needs to be replaced.
5. The phenomenon of air leakage at the reversing valve base bolt and the through bolt nut is likely to be caused by trachoma or cracking of the nitrogen chamber body material.
Question 15. What happens to the nitrogen chamber leak?
Processing method:
At the beginning, the attack was slow and there was no strength. Then the blow was stopped. After the body had hydraulic oil, the nitrogen gas was sprayed with a mist of hydraulic oil.
Question 16. What is the instability of the hammer when the strike frequency is unstable?
Processing method:
(1) It may be instability caused by the problem of the host.
(2) The hydraulic oil is too small and the flow rate is insufficient.
(3) The relief valve is damaged.
(4) Piston, control valve, backup valve, slight strain.
(5) The pipeline pressure is not enough.
(6) The pipeline is blocked.
(7) The instability caused by the reaction force of the broken object.
(8) The bolts are loose and the size of the steel is not correct.
Question 17. What is the situation caused by poor oil return?
production methods:
(1) The breaker hammer is weak.
(2) The frequency is too slow.
(3) The oil temperature is easy to high.
(4) Waste diesel.
It is also easy to cause the frequency of the hammer to be unstable. This kind of situation is easy to occur when the oil return filter is not replaced according to the specified time, which causes the filter element to clog and hinder the smooth flow of the return oil. The oil return pipe directly returns to the multi-way valve. After long-term work, the multi-way valve is easy to issue the hydraulic oil to heat up faster, reducing the impact of the breaker.
Question 18. What should the breaker line be installed without pressure?
Processing method:
(1) Check that the piping is installed correctly.
(2) The shut-off valve opens to detect if there is pressure or pressure in the pipeline.
(3) Check if the relief valve is damaged.
(4) Is there enough pressure on port A?
(5) If all of the above are normal, see if the backup valve is stuck.
Question 19. What are the main reasons for the hammer release? How to judge?
cause:
