Excavator Lovers Need to Know How to Maintain The Excavator

The purpose of regular maintenance of the excavator is to reduce the failure of the excavator, shorten the downtime of the excavator, extend the service life of the excavator, and improve the working efficiency of the excavator. According to scientific statistics, as long as the fuel, other oil, water and air inside the excavator are managed, it can reduce the failure by 70%. After all, the failure of many excavators is due to the lack of regular maintenance.

1. Fuel management

Different types of diesel oil should be selected according to different working environment temperatures. Try to choose high-quality diesel. The high content of paraffin and sulfur in inferior diesel will cause damage to the engine of the excavator. It is important to note that diesel cannot be mixed with impurities such as dust and water, which would otherwise cause severe wear on the fuel pump. After the daily operation, the fuel tank should be filled with fuel to prevent water droplets from forming on the inner wall of the tank. Open the drain valve at the bottom of the fuel tank before the daily work. After the engine fuel is exhausted or the filter element is replaced, the air in the lane must be drained.

2. Management of lubricating oil

The use of lubricating oil can reduce the wear on the surface of the excavator components during exercise and prevent noise. Do not mix dust, sand, water and other impurities when storing the lubricant. When filling the lubricating oil, try to clean all the old oil to prevent the impurities from sticking.

3. Management of other oils

Other oils include engine oil, hydraulic oil, gear oil, etc. The oils of different models cannot be mixed. Different types of excavator oils are added with different additives in the production process. It is necessary to ensure oil cleaning and prevent debris (water, Dust, granules, etc. are mixed in, and the type of oil is selected according to the ambient temperature and use. The viscosity of the gear oil is relatively large to accommodate large transmission loads, and the viscosity of the hydraulic oil is relatively small to reduce the resistance to liquid flow. If the ambient temperature is high, oil with high viscosity should be used. For low ambient temperature, oil with low viscosity should be used.

4. Filter maintenance

The filter element acts as a filter to filter impurities in the oil path or the gas path, preventing it from invading the inside of the system and causing malfunction. Various filter elements should be replaced periodically according to the requirements in the operation and maintenance manual. When replacing the filter element, it should be checked whether metal particles are attached to the old one. On the filter element, if there are metal particles found, it is necessary to find the cause and take corresponding measures. The use of high-quality filter elements that meet the requirements of the excavator, the poor filter capacity of the inferior filter element will seriously affect the normal use of the excavator, which may cause serious consequences, and will not be worth the candle.

5. Regular maintenance

Every 100H maintenance project

Check the oil level in the swing mechanism box, the water and sediment discharged from the fuel tank, the boom cylinder pin shaft, the boom pin, the boom cylinder rod end, the arm cylinder pin shaft, the boom , stick connecting pin, stick cylinder rod end, bucket cylinder head pin shaft, half rod connecting rod connecting rod, stick rod, bucket cylinder rod end, bucket cylinder head pin shaft, stick connecting rod Connecting pin.

Every 250H maintenance project

Check the tension of the fan belt, check the tension of the air conditioner compressor belt, check the oil level in the final gearbox, check the battery electrolyte, replace the oil in the engine oil sump, replace the engine filter, and lubricate the slewing ring.

Every 500H maintenance project

At the same time, every 100 and 250H maintenance items, replace the fuel filter, clean the air filter inside and outside the air conditioner system, replace the hydraulic oil vent filter, check the height of the rotary pinion lubricant, check and clean the radiator fin, oil cooling Heat sink and cold heat sink, replace the hydraulic oil filter and replace the oil in the final gearbox.

Maintenance items per 1000h

At the same time, every 100, 250 and 500h maintenance items, replace the oil in the swing mechanism box, check the oil level of the damper housing (return oil), check all the fasteners of the turbocharger, check the turbocharger rotor The clearance, the inspection and replacement of the tension of the generator belt, the replacement of the anti-corrosion filter, and the replacement of the oil in the final transmission.

Maintenance items every 2000h

First complete every 100, 250, 500 and 1000h maintenance items, clean the hydraulic tank filter, clean, check the turbocharger, check the generator, start the motor, check the engine valve clearance, check the shock absorber.

6. Excavator maintenance for not used for a long time

When the excavator is stored for a long time, the whole machine should be washed and dried before being stored in a dry indoor environment. If it is limited to outdoor conditions, the machine should be parked on a well-drained concrete floor. Full fuel tank, lubricate all parts, replace hydraulic oil and oil. Start the engine once a month and operate the machine.

Introduction and Working Principle of Excavator Hydraulic Breaker

Introduction of excavator hydraulic breaker

The excavator hydraulic breaker is referred to as “breaker” or “crusher”. The power source of the excavtor hydraulic breaker is the pressure provided by the excavator. It can crush stones and rocks more effectively during construction and improve work efficiency. The hydraulic breaker is selected according to the model of the excavator and the environment in which the work is performed. The structure of the excavator hydraulic breaker is mainly divided into three blocks: the upper cylinder (nitrogen chamber), the middle cylinder (cylinder), and the lower cylinder. The three are connected by four through-body bolts. The upper cylinder is used to store low-pressure nitrogen. The middle cylinder is a piston, an accumulator, an oil seal, a gas exchange valve, etc., and the lower cylinder has steel brazing, flat pins, horizontal pins, inner and outer bushings, and the like.

Working principle of excavator hydraulic breaker

Excavator hydraulic breaker detailed working principle first,
Return acceleration phase: At the beginning of the piston return stroke, the last impact of the piston has ended and is in a momentary pause state. At this time, the main valve V2 chamber is a low pressure chamber, and the V4 chamber is a constant high pressure chamber, so the main spool is at the lower limit position. In this way, the front chamber V1 of the piston communicates with the high-pressure oil through the main valve core, and the rear chamber V3 of the piston is always in communication with the oil return chamber, which is a low pressure. Therefore, the piston accelerates in the return stroke under the action of the high pressure oil in the front chamber, and simultaneously compresses the tail nitrogen. The chamber is nitrogened for adiabatic compression.

Excavator hydraulic breaker detailed working principle Second,
The return brake movement: the piston continues to move back to the action under the action of high pressure oil. When the lower side of the middle section of the piston crosses the lower side of the control port, the high pressure oil in the V1 chamber enters the main valve. In the V2 chamber, the hydraulic pressure acting on the main spool through the V2 chamber is greater than the hydraulic pressure acting on the main spool at the V4 chamber, thereby forcing the spool to start the reversing motion. The movement of the spool gradually reduces the high-pressure oil entering the V1 cavity, so that the return stroke force corresponding to the piston is gradually reduced, and the return resistance applied by the compressed nitrogen is getting larger and larger, and the piston is transferred to the return stroke. Braking phase. The spool will eventually shut off the pressure oil in the V1 chamber and the piston will quickly stop the return stroke.

Excavator hydraulic breaker detailed working principle Third,
Stroke acceleration movement: When the piston stops the return movement, it will immediately turn into the stroke movement phase. At this time, the main spool has opened the oil passage of the front chamber V1 of the piston to the oil return chamber of the main spool, so that the oil in the front chamber of the piston can be smoothly discharged. At this point, the piston begins a rapid stroke motion under the adiabatic expansion force of nitrogen. When the piston is in stroke motion, the spool will reliably stay in the upper limit position.

Excavator hydraulic breaker detailed working principle Fourth,
The special state: the piston hits the pause state Under the nitrogen chamber adiabatic expansion of the nitrogen chamber, the piston is quasi-accelerated (the banquet acceleration is gradually reduced). When the upper side of the middle section of the piston passes over the upper side of the control port, the V2 cavity of the main spool communicates with the return oil, and the V2 cavity becomes a low pressure chamber. The spool will begin to reverse the downward movement under the action of the high pressure oil in the V4 chamber. At this point, the piston with sufficient energy has been struck against the drill rod to complete the impact action. The spool continues to move downwards, and when the spool moves to the lower limit position, the piston is in an instantaneous pause phase. At this point, the piston ends a working cycle. Subsequently, the piston rebounded after the impact and began the next work cycle.

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.