Komatsu PC360 Excavator Rotary Motion Jitter

Whether the excavator is loaded or unloaded, the rotating action is essential. Hundreds of thousands of cycles can be successfully performed every day to ensure the quality and efficiency of the project.

Due to the high frequency of use, faults such as swing, sway, and slow movement often occur during construction.

Today, what I want to share with you is how to effectively handle the first detected swing motion. Save time and stop the machine, accurately eliminate the fault, and leave no hidden dangers.

Fault phenomenon:

This is a typical failure case. During the on-site inspection, the maintenance personnel learned that the Komatsu PC360 excavator had a slight jitter at the beginning of the swinging motion, which was normal after about two or three seconds, and stopped when the handle returned to the neutral position. There was also jitter in the first two seconds.

Excavator swing motion jitter analysis check:

According to the daily maintenance experience, the maintenance personnel first analyzed the problem of the rotary motor, disassembled the motor cover, and found that the contact surface between the distribution plate and the cylinder block was seriously worn. At that time, people thought that the fault had occurred.

However, after replacing the new test machine, the test machine failure still exists. The maintenance personnel disassemble the swing motor again and check it carefully. It was found that the seal gap under the rotary brake cylinder was small. After replacing the seal, the test machine is normal.

process result:

After replacing the seal under the brake cylinder, it works normally. There are a lot of machine friends who have seen some loops here. Why is there a small gap in the seal that can cause such a serious failure?

If there is a gap in the seal, the brake cylinder will not be tightly sealed and the braking time will be longer. When the rotation starts, the brake is not fully released, the spring will shake for a while, and when the rotation stops, the braking time will be shortened. The effect of the valve is not obvious, so it will also shake.

You Must Know The Seven Reasons Why The Excavator Tubing Bursts

Hydraulic tubing electric squibs are a headache for many excavator masters. Due to the leakage of hydraulic oil caused by the electric squib, maintenance after the accident is time consuming and costly. So what are the common causes of hydraulic tube bursts?

1. use inferior hydraulic pipe

Many people in the original hydraulic pipe damage, in order to be cheap, many people choose quality inferior hydraulic pipe that does not meet the standard, the performance and reliability of this hydraulic pipe is far lower than the original.

In addition, the metal joints at both ends of the hydraulic pipe are poorly crimped, and the sealing and reliability cannot be guaranteed. After using for a period of time, there will be fuel consumption and even oil leakage. Therefore, the replacement of hydraulic pipes must use regular large brand products.

2. the hydraulic system pressure is too high

The pre-set pressure of the hydraulic system increases the likelihood of an explosion. The method is to test the pressure generated by the main pump in combination with various actions. If the pressure value is confirmed to be too large, the pressure of the multi-way valve can be appropriately reduced.

3. the hydraulic oil temperature is too high

If your machine's hydraulic system is hot, it will also affect the sealing of the hydraulic components, causing the pipe to explode; in addition, high temperatures can cause the hydraulic components to expand, causing the valve plug and the valve body to get stuck, causing local high temperatures and causing the pipe to burst.

4. Mix different grades of hydraulic oil

The excavator factory uses 46 hydraulic oil by default. If you add 68 hydraulic oil commonly used in the accessory library during use, the hydraulic oil will be unstable and damage the parts. High viscosity hydraulic oil has poor fluidity, which can cause high pressure in the hydraulic system, causing pipeline leakage.

5. bad operating habits

If the operator is rude during operation, a large impact load can create a transient impact pressure in the hydraulic system. Impact pressure can cause premature failure of high pressure tubing joints and hoses, pressure or bursts, greatly reducing hydraulic pressure. The service life of the pipe. In addition, rude operations can affect the durability of other components, resulting in frequent mechanical failures. Therefore, the operation of the excavator must be gentle, do not do high-intensity, high-risk movements.

6. hydraulic tube corrosion

Although most hydraulic pipes currently have a certain degree of corrosion resistance, after a long period of exposure of rubber products to diesel oil, the colloids are fluffy. Produce certain adverse effects, try not to let the hose contact with gasoline and diesel. Generally, rubber will expand the colloid and fluff when soaking gasoline and diesel for a long time. Therefore, in normal use, contact with corrosive liquids such as diesel should be avoided, and the outer surface of the hydraulic pipe should be cleaned frequently.

7. Abnormal vibration of hydraulic pipe

Both the gear pump and the plunger pump have oil pulses during operation. This pulsation causes high frequency vibration of the hydraulic pipe, and this high frequency vibration cannot be completely eliminated. Long-term abnormal vibrations can cause fatigue and wear of the hydraulic pipe. Therefore, be sure to check the pipe clamps and protective sleeves of the hydraulic pipes. Once the pipe clamp is loose, it will wear the hydraulic pipe and even wear the hydraulic pipe.

Reasons For Derailment Of Excavator Tracks

In this article, let's look at the cause of the track derailment of the excavator.

1. For external reasons, the chain is digging and the tracks are in the dirt or gravel. The rugged terrain will cause the track shoes to be seriously out of balance and prone to failure.

2. The operator's operational skills are not enough. When the excavator turns or walks, it may cause misalignment.

3. The four-wheeled belt is not on the same plane, causing the track to derail, which is often caused by damage to the guide wheels. Care must be taken to see if the screws on the guide wheel are missing, if there is a break, the groove of the card guide wheel, if there is any modification, etc., if necessary, the guide wheel should be replaced.

4. When the oil seal of the tensioning cylinder leaks and the spring of the tensioning device breaks, the track belt will be too loose, causing melting problems. It should be checked in time whether the fastening cylinder forgets to butter and whether the fastening cylinder leaks oil.

5. When the chain protection device is severely worn, the excavator is also lost. The chain guard does not limit the track very well, and the track shoe swings too much, causing the chain to break.

6. The excavator travels for too long, the track must be worn, and the wear of the chain ribs, chain barrels, etc. on the track will also cause the track to lose its lock.

7. For the ring gear of the drive motor, when the wear is too severe, it needs to be replaced in time, which also causes the excavator to lock.

Excavator Computer Board Failure Analysis

I believe that the friends who started the excavator have encountered the failure of the computer board. Today we will analyze the cause of the failure of the excavator computer board.

1. Excavator instrument or computer board water

If the internal water enters the computer board during charging, basically the copper foil of the internal circuit board will be completely burnt and oxidized and cannot be repaired; in addition, the plug wire harness of the computer board will enter the water, causing the pins of the computer board to oxidize, resulting in pins. Poor contact with solder joints on the board.

2. Throttle motor failure or abnormal operation

Motor overheating and short circuit can easily cause the computer panel throttle control circuit to burn out. Therefore, it is necessary to pay attention to keeping the throttling motor clean and clean, reducing the possibility of failure. In addition, when the excavator is energized, the throttle motor linkage is pulled. If you pull the throttle motor connecting rod hard, it may cause the computer board to burn out.

3. Poor contact of battery wire pile head, oxidation of contact surface

The electrical system on the excavator is the same as the household appliance. Poor contact of the fuse can easily cause the bulb to burn out. Poor contact between the battery stub and oxidation of the contact surface can greatly increase the possibility of damage to the computer board and the instrument, so it is also important to ensure that the battery head contacts.

4. Battery line reverse

This is not a small problem. If the battery cable is connected to the lamp, the fuse will burn out and the power circuit and CPU of the computer board will burn out. Some excavators have diodes on their pipes. If the power supplies are reversed, they are basically the same. The diode will also burn out.

5. Manual misoperation

When many people suspect that electronic components are not working properly, a short circuit method is used to test whether the line is normal. This method is very harmful and is not recommended.

Excavator Troubleshooting Methods That Novices Need To Know

In this article, let's discuss the faults and solutions that often occur in excavators for beginners' reference.

First of all, the sound of the cab is not normal. Check if the silicone oil damper at the four corners of the cab is loose. When the damper screw is loose, the cab will generate abnormal noise, especially when the engine is running at high speed, the cab and the surrounding area will emit abnormal noise. The glass is particularly noticeable, so we need to tighten the four screws under the cab.

The cab has a slight vibration when there is a click in the rotating part. This vibration is caused by impurities between the gear and the gear or after the gear is broken. When rotating to a fixed position, if there is abnormal noise, the rotary motor appears. When vibrating, check the gear oil and lubricate the butter with impurities or nails.

The hydraulic pump is abnormally vibrating. First, we need to check if the hydraulic oil is insufficient. Then, the professional hydraulic service technician checks whether the pressure is normal, whether the engine power is matched, whether the hydraulic pump output pipe is shaking, whether the regulator is issued, and the safety should be checked. Check if the solenoid valve switch is in place, check the hydraulic oil and return oil filter for metal powder, and judge whether the plunger is worn. Shake the pilot tubing and check that the pilot filter and filter fittings are clogged.

If the engine is vibrating, check the four foot pads of the engine for damage. If it is damaged, replace it with a new one. This will ensure the balance of the engine.

What If the VOLVO Excavator Motor Speed Is Low? How to Fix It?

When the Volvo excavator suddenly has a low motor speed situation, what should we do? How to fix Volvo excavator motor?(travel motor )As an excavator lover, I will analyze the reasons first.

I think the Volvo excavator may have low motor speed for the following reasons:

1. The internal leakage is increased due to loosening of the fastening bolts of the piston motor base, then creates a decrease in the excavator motor speed.

2. Due to the failure of the flow control valve, pressure regulating valve, hydraulic pump and other components, the flow received by the piston motor does not meet the requirements, resulting in a low excavator motor speed situation.

3. The sliding surface of the piston motor is seriously worn, causing the hydraulic oil to overflow from the high side to the low side, resulting in low motor speed.

Correspondingly, the solution is as follows:

1. Fasten the pedestal bolts according to the specified torque.

2. Check whether the flow of the piston motor inlet meets the requirements, check whether the parts are faulty, and if necessary, repair in time.

3. Check the wear and tear of the moving parts of the motor for repair or replacement.

For reference:excavator parts drawing system

Excavator Repair Tips: Fix Hydraulic Excavator's Powerless Maintenance

When hydraulic excavator is working for a long time, powerless is usually happened to excavator. This article will tell you how to repair the excavator's powerless.Take Komatsu PC200-6 for example.

Let us briefly understand Komatsu PC200-6, Komatsu PC200-6 is a very popular excavator. It is very suitable for almost all kinds of complicated situations, and is highly praised by excavator lovers for its excellent and stable performance.

Komatsu PC200-6 Excavator Parameter Configuration

Machine working weight(kg): 19180

Bucket capacity(m³): 0.8

Boom length(mm): 5700

Stick length(mm): 1840

Country of origin: Japan

Tonnage(ton): 20

Grounding specific pressure(Kpa): 44.1

Swing speed(rpm): 12.4

Walking speed(km/h): 5.5

Climbing ability(%): 70/35°

Main overflow set pressure(Mpa): 34.818

Main pump maximum flow(l/min): 412

Maximum excavation height(mm): 8895

Maximum unloading height(mm): 6065

Maximum vertical excavation depth(mm): 496590

As an excavator lover, when the PC200-6 excavator appeared to be weak and slow in operation, we speculated that the following problems may have occurred.

1. The main pump pressure is low

The PC200-6 excavator uses a double swash plate type axial variable displacement piston pump. Under normal circumstances, the main pump output oil pressure is above 30MPa. If the amount of wear between the plunger of the main pump and the cylinder or between the end face of the cylinder and the distribution plate exceeds the standard (the clearance between the plunger and the cylinder should be less than 0.02 mm, the contact area between the end face of the cylinder and the distribution plate should be no less than 90%), which will cause the main pump output pressure to be low. Which is reflected in the mechanical working device, and the whole machine will work weakly.

2. The main pump output flow control valve group is faulty.

On the premise that the power of the main pump and the engine is highly matched and the engine can be fully utilized, the output flow of the main pump of the machine changes with the change of engine power. If there is a fault in the control valve group used to regulate the main pump output flow, such as the PLS feedback circuit blockage, the LS valve spool stuck, the PC valve spool stuck or the PC-EPC solenoid valve internal coil is burned, etc. The main pump is always in a state of constant flow. If the main pump is always in a small flow state, the machine will be weak and slow when it is working.

Similarly, if the swash plate, servo piston, and the like of the main pump that directly controls the main pump flow change are stuck, the output flow rate of the main pump does not change.

3. The control pressure of the pressure reducing valve output is low

Under normal circumstances, the pressure reducing valve can reduce the output oil pressure of the main pump and stabilize it at 3.3 MPa to form a control oil pressure. If the oil valve is too dirty and the conical valve plug on the pressure reducing valve is not tightly closed, the output pressure of the pressure reducing valve will be lower than 3.3 MPa. At this time, no matter how the operation handle is operated, the control oil pressure is always low, and the movement amount of the spool of the main control valve of various working devices is too small, so that the flow rate to the working device is also small, resulting in the weakness of the whole machine.

4. The overflow pressure of the main relief valve is low

The main relief valve limits the pressure of the entire hydraulic system to 32.5 MPa. For high pressures above this value, the main relief valve will open to relieve pressure to protect the system from damage. If the small hole on the main relief valve spool is blocked due to poor oil quality, the spool is normally open, or the set relief pressure of the main relief valve is low, the actual relief pressure will be low, that is, the system The pressure is low.

5. The unloading valve is faulty

When the driver starts the engine and puts the operating lever in neutral, the main pump output hydraulic oil is directly returned to the tank through the unloading valve, and the unloading pressure is 3 MPa. If the oil is too dirty, the unloading valve spool will not be closed tightly. When the machine is working, the output oil of the main pump will pass through the unloading valve and pass through the fuel tank, so that the system cannot establish high pressure. Similarly, if the unloading valve is used When the 0-ring seal that blocks the PlS pressure oil and the fuel tank is damaged, the main pump hydraulic oil will also flow directly back to the tank.

6. LS bypass valve is faulty

The LS bypass valve can leak a portion of the P15 pressure oil on the LS circuit through two small holes (slightly) on the valve body to increase the softness of the machine operation. If the o-ring seal on the valve body is damaged, the PL5 pressure oil will directly communicate with the fuel tank, which indirectly causes the unloading valve to open normally, causing the working devices to be weak and slow, and if the PC200-6 excavator appears to work. The weakness is largely attributable to the poor oil quality of the hydraulic fluid. Therefore, replacing the hydraulic oil filter on time (specified to be replaced every 500 h) and paying attention to monitoring the hydraulic oil quality (viscosity, fluidity and presence or absence of suspended solids) are the key to avoiding or reducing such failures.

The above is the main repair process for the excavator's weakness. This article only uses the Komatsu PC200-6 as an example. Mainstream excavators such as VOLVO EC360/VOLVO EC460 can also refer to this article. For details, please refer to the official maintenance manual.