The first manual excavator has been around for more than 130 years.Due to the application of hydraulic technology, in the 1940s, there were suspended excavators equipped with hydraulic backhoes on tractors. In the early and mid-1950s, towed full-rotation hydraulic excavators and crawler-type full-hydraulic excavators were successively developed.
The first manual excavator has been around for more than 130 years. During this period, it has experienced a gradual development process from steam-driven bucket rotary excavators to electric-driven and internal combustion engine-driven rotary excavators, and fully automatic hydraulic excavators using electromechanical-hydraulic integration technology.
Due to the application of hydraulic technology, in the 1940s, there were suspended excavators equipped with hydraulic backhoes on tractors. In the early and mid-1950s, towed full-rotation hydraulic excavators and crawler-type full-hydraulic excavators were successively developed. The initial trial-produced hydraulic excavators used hydraulic technology from aircraft and machine tools, lacked hydraulic components suitable for various working conditions of excavators, had unstable manufacturing quality, and incomplete supporting parts. Since the 1960s, hydraulic excavators have entered a stage of promotion and vigorous development. The number of excavator manufacturers and varieties in various countries has increased rapidly, and the output has soared. Between 1968 and 1970, the output of hydraulic excavators accounted for 83% of the total output of excavators, and is now close to 100%.
2. The structure of the excavator Common excavator structures include power unit, working device, slewing mechanism, operating mechanism, transmission mechanism, walking mechanism and auxiliary facilities.
From the appearance, the excavator consists of three parts: working device, upper turntable and walking mechanism.
3. The development history of excavators Originally, the excavator was manual. It has been more than 130 years since its invention. It has experienced various driving modes such as steam drive, electric drive, and internal combustion engine drive.
After the 1940s, hydraulic technology was applied to excavators, and the crawler-type fully hydraulic excavator that is common today was developed in the 1950s.
The three most important parameters of the excavator: vehicle weight (mass), engine power and bucket capacity.
In 1951, the first fully hydraulic backhoe excavator was launched by the Poclain factory in France, thus creating a new space in the field of excavator technology development.
3. Classification of excavators The following is the classification of common excavators:
Classification of excavators 1: Common excavators are divided into two types according to the driving mode: internal combustion engine driven excavators and electric driven excavators. Among them, electric excavators are mainly used in plateaus with hypoxia, underground mines and other flammable and explosive places.
Classification of excavators 2: According to different walking methods, excavators can be divided into crawler excavators and wheeled excavators.
Classification of excavators 3: According to different transmission methods, excavators can be divided into hydraulic excavators and mechanical excavators. Mechanical excavators are mainly used in some large mines.
Classification of excavators 4: According to the purpose, excavators can be divided into general excavators, mining excavators, marine excavators, special excavators and other different categories
4. Full hydraulic full rotary excavator
Today's excavators account for the vast majority of fully hydraulic full rotary excavators.
Caterpillar 385B excavator
Caterpillar 385B excavator
Hydraulic excavators are mainly composed of engines, hydraulic systems, working devices, walking devices and electrical controls. The hydraulic system consists of hydraulic pumps, control valves, hydraulic cylinders, hydraulic motors, pipelines, fuel tanks, etc. The electrical control system includes monitoring panels, engine control systems, pump control systems, various sensors, solenoid valves, etc.
According to its structure and purpose, it can be divided into: crawler type, tire type, walking type, full hydraulic, semi-hydraulic, full rotation, non-full rotation, general type, special type, articulated type, telescopic arm type and other types.
The working device is a device that directly completes the excavation task. It is articulated by three parts: boom, dipper and bucket. The boom lifting and lowering, dipper arm extension and bucket rotation are all controlled by reciprocating double-acting hydraulic cylinders. In order to meet the needs of various construction operations, hydraulic excavators can be equipped with a variety of working devices, such as excavation, lifting, loading, leveling, clamps, bulldozers, impact hammers and other working tools.
The rotating and walking device is the body of the hydraulic excavator, and the power unit and transmission system are installed on the upper part of the turntable. The engine is the power source of the hydraulic excavator. Most of them use diesel. In a convenient site, an electric motor can also be used instead.
The hydraulic transmission system transmits the power of the engine to the hydraulic motor, hydraulic cylinder and other actuators through the hydraulic pump, driving the working device to move, thereby completing various operations.
5. Issues that should be paid attention to when driving an excavator 1. The excavator is a fixed asset with a large economic investment. In order to increase its service life and obtain greater economic benefits, the equipment must be assigned to specific people, machines, and positions, and the responsibilities must be clearly defined. When the position must be transferred, the equipment should be explained.
2. After the excavator enters the construction site, the driver should first observe the geology of the working surface and the surrounding environment. There should be no obstacles within the rotation radius of the excavator to avoid scratches or damage to the vehicle.
3. After the machine is started, no person is allowed to stand in the bucket, on the shovel arm or on the crawler to ensure safe production.
4. When the excavator is working, no person is allowed to stay or walk within the rotation radius or under the bucket. Non-drivers are not allowed to enter the cab to touch and move around, and are not allowed to bring training drivers to avoid damage to electrical equipment.
5. When the excavator is moving, the driver should observe and honk the horn before moving to avoid accidents caused by people near the machine. The position after moving should ensure that there are no obstacles in the space of the excavator's rotation radius. It is strictly forbidden to operate in violation of regulations.
6. After work, the excavator should be moved away from the low-lying area or the edge of the trough (ditch), parked on flat ground, and the doors and windows should be closed and locked.
7. The driver must do a good job of daily maintenance, inspection and maintenance of the equipment, and keep a daily record of the use of the equipment. If there is a problem with the vehicle, it cannot be operated with a problem, and it should be reported and repaired in time.
8. The cab must be clean and tidy, and the surface of the vehicle must be kept clean, free of dust and oil; develop the habit of wiping the car after work.
9. The driver must make a daily shift record in time, make statistics on the work content of the day, handle the procedures for odd jobs or zero items outside the project in time, and keep records for settlement.
10. Drivers are strictly prohibited from drinking at noon and driving after drinking during work. If found, they will be given economic penalties, and the economic losses caused will be borne by themselves.
11. For man-made damage to vehicles, the cause should be analyzed, the problem should be found, the responsibilities should be clarified, and economic penalties should be imposed according to the severity of the responsibilities.
12. A high sense of responsibility should be established to ensure safe production, and good communication and service work with the construction party should be done conscientiously, bilateral relations should be established, a good work style should be established, and efforts should be made for the development and benefits of the enterprise.
VI. Maintenance of excavators
The purpose of regular maintenance of excavators is to reduce machine failures, extend the service life of the machine, shorten the downtime of the machine, improve work efficiency, and reduce operating costs.
As long as fuel, lubricating oil, water and air are managed well, 70% of failures can be reduced. In fact, about 70% of failures are caused by poor management.
1. Fuel management
Different brands of diesel should be selected according to different ambient temperatures (see Table 1); Diesel should not be mixed with impurities, dust and water, otherwise the fuel pump will wear out prematurely; the high content of paraffin and sulfur in inferior fuel will damage the engine; the fuel tank should be filled with fuel after daily operation to prevent water droplets from forming on the inner wall of the fuel tank; open the drain valve at the bottom of the fuel tank to drain water before daily operation; after the engine fuel is exhausted or the filter element is replaced, the air in the circuit must be discharged.
Minimum ambient temperature 0℃ -10℃ -20℃ -30℃
Diesel brand 0# -10# -20# -35#
2. Management of other oils
Other oils include engine oil, hydraulic oil, gear oil, etc.; oils of different brands and grades cannot be mixed; different types of excavator oils have different chemical or physical additives added during the production process; the oil should be kept clean to prevent the mixing of debris (water, dust, particles, etc.); the oil brand should be selected according to the ambient temperature and purpose. When the ambient temperature is high, you should use oil with high viscosity, and when the ambient temperature is low, you should use oil with low viscosity; the viscosity of gear oil is relatively high to adapt to larger transmission loads, and the viscosity of hydraulic oil is relatively low to reduce liquid flow resistance.
Table 2 Selection of oil for excavators
Container Outside temperature ℃ Oil type Replacement cycle h Replacement volume L
Engine oil pan -35-20 CD SAE 5W-30 250 24
-20-10 CD SAE 10W
-20-40 CD SAE 10W-30
-15-50 CD SAE 15W-40
0-40 CD SAE 30
Slewing mechanism box -20-40 CD SAE 30 1000 5.5
Shock absorber housing CD SAE 30 6.8
Hydraulic oil tank CD SAE 10W 5000 PC200 type: 239
PC220 type: 246 CD SAE 10W-30 CD SAE 15W-40 Final drive CD SAE90 1000 5.4
3. Lubrication oil management
Using lubricant (butter) can reduce the wear of the movement surface and prevent noise. When storage of lubricating fat, you cannot mix into dust, sand, water and other impurities; it is recommended to use lithium-based lubricating grease G2-L1, good abrasion performance, and applicable to heavy loading. When adding it, try to squeeze all the old oil as much as possible. Out and clean to prevent sand and soil from adhesion.
4. The maintenance of the filter element
The filter element plays the role of impurities in the oil -filtering road or air path, which prevents them from invading the inside of the system and causes failure; various filter elements should be replaced regularly according to the requirements of (operating maintenance manual); when replacing the filter element On the filter element, if there are metal granules, it is found to have timely diagnosis and improvement measures; use a pure filter element that complies with the machine. The filtration capacity of the pseudo -inferior filter element is poor, and the quality of the noodles and materials of the filter layer does not meet the requirements, which will seriously affect the normal use of the machine.
5. The content of regular maintenance
① After 250h, the fuel filter and additional fuel filter should be replaced after the new machine work; check the gap between the engine valve.
② Daily maintenance; inspection, cleaning or replacement of the air filter element; cleaning and cooling system; inspection and tightening the band bolt; inspection and adjustment of the tightness of the track; check the air heater; replace the fighting tooth; Washing liquid surface; check and adjust air conditioners; clean the inland plate of the cab; replace the crusher filter element (optional parts). When cleaning the cooling system, after the engine is fully cooled, slowly loose the water inlet cover, release the pressure inside the water tank before leaving the water; do not clean it during the engine work. When liquid, the machine should be parked on the horizontal ground; replace the coolant and anticorrosive device according to Table 3. The ratio of antifreeze to water is required by Table 4.
Cooling type Cooling system Cooling system Internal cleaning and replacement cycle anti -corrosion device replacement cycle
AF-ACL antifreeze (super-frozen liquid) every 2 years or every 4000h every 1000H or change the coolant
AF-PTL antifreeze (long-acting antifreeze) or 2000h per year or 2000h
AF-PT antifreeze (winter type) every 6 months (only added in autumn)
Table 4 The mixed ratio of antifreeze and water
Environmental temperature ℃/capacity L --5 -10 -15 -20 -25 -30
Anti -frozen liquid PC200 5.1 6.7 8.1 10.2 11.10
PC220 5.4 7.0 8.6 9.6 10.7 11.65
Water PC200 17.1 15.5 14.2 13.1 12.0 11.10
PC220 17.9 16.3 14.9 13.7 12.6 11.65
③ Check the inspection items before the engine. Check the height of the liquid surface of the coolant (add water); check the engine oil level, add oil; check the fuel oil level (fuel); check the liquid oil level (adding liquid oil); check whether the air filter element is blocked; check the wire; Check whether the speaker is normal; check the lubrication of the bucket; check the water and sediments in the oil -water separator.
④ Maintenance items per 100. Axic shaft of the head cylinder head; the arm of the arm of the arm; ; Half -rod connecting rod connection; tap rods, bucket cylinder rod ends; bucket cylinder head sales shafts; bucket rod connecting rod connection; check the fuel level in the rotary mechanism box (add oil); from the fuel tank; from the fuel tank Excess water and precipitates.
⑤ Maintenance projects every 220h. Check the oil level (with gear oil) in the final transmission box; check the battery electrolyte; replace the oil in the engine oil bottom shell, replace the engine filter element; lubricate the rotary support (2); check the tension of the fan belt, and check the inspection The tightness of the air -conditioning compressor belt is tensioned and adjusted.
⑥ Maintenance items every 500h. At the same time, carry out per 100 and 250h maintenance items; replace the fuel filter element; check the height (plus lubricating fat) of small gear lubrication (plus lubricating fat); Filter element; replace the oil in the final transmission box (only at 500H for the first time, once 1000h once); clean the air filter element inside and external in the air conditioner system; replace the hydraulic oil passing filter element.
⑦ Maintenance projects every 1000H. At the same time, perform maintenance items per 100, 250 and 500h; replace the oil in the rotary mechanism box; check the oil level (return oil) of the shock absorber housing; check all fasteners of the turbocharger; check the turbocharger rotor The gap; check and replace the tightness of the charger's belt; replace the antifrocroachment filter element; replace the oil in the final transmission box.
⑧ Maintenance projects per 2000h. First complete the maintenance items of 100, 250, 500, and 1000H; clean the hydraulic fuel tank filter; clean and check the turbocharger; check the electrical machine, start motor; check the engine valve gap (and adjust); check the shock absorber.
的4000H or more maintenance. Increase the inspection of the pump every 4000H; the project that replaces the hydraulic oil every 5000H.
⑩ Long -term storage. When the machine is stored for a long time, in order to prevent the hydraulic cylinder piston rust, the work installation should be placed on the ground; after washing and drying the whole machine, it should be stored in an indoor drying environment; The machine is parked on the cement floor with good drainage; the fuel tank is filled before storage, the lubrication of all parts, replacing hydraulic oil and oil, and the metal surface exposed by the hydraulic cylinder pistol is applied to a thin layer of butter, removed the negative electrode terminal of the battery, or Remove the battery and store separately; add an appropriate proportion of antifreeze to the cooling water according to the lowest ambient temperature; start the engine once a month and operate the machine to lubricate each motion component and charge the battery at the same time; turn on the air conditioner and run for 5-10min.
6. Maintenance of excavator hydraulic system 1. Reasonable selection of hydraulic oil
(1) Hydraulic oil viscosity (ISO VG, the viscosity unit is mm2/s)
(2) The viscosity index (VI)
(3) Other comprehensive performance
2. Good hydraulic oil cooling system
3. Inspection of related hydraulic parameters in the system
4. Exclude non -normal internal leakage
5. Prevent component volume efficiency decreased
If the conditions permit, the component should be detected on the test bench, and the professional manufacturer should be guided and repaired
1. Reasonably choose hydraulic oil
(1) Hydraulic oil viscosity
The principle of determining the viscosity of hydraulic oil is that under the premise of considering the temperature and efficiency of the hydraulic circuit, the hydraulic oil viscosity (for pumps and motors and other components) is in the best range (16-36x10-6mm2/s); the lowest environment is the lowest environment. The viscosity of the short-time cold start corresponding to the temperature is ≤1000x10-6mm2/s; and the viscosity of the maximum leakage of the maximum leakage of oil at 90 ° C in a short period of time is ≥10x10-6mm2/s.
(2) The viscosity index (VI)
This indicator directly reflects the nature of the viscosity of oil changes with temperature changes (that is, the viscosity characteristics of the oil). Conversely, bigger. The viscosity index of anti -abrasive liquid pressure oil of well -known foreign manufacturers (such as Mobil, Shell, etc.) is VI ≥ 110, and the viscosity index of domestic high -grade anti -abrasion oil oil is around 95. The viscosity index of hydraulic oil (HV) and multi -stage engine oil produced by foreign countries are VI> 140. This point for users who use large imported hydraulic excavators to use domestic hydraulic oil (or use engine oil as hydraulic oil). Decreasing the viscosity index will reduce the environmental temperature range adapted by the oil. If it is not used, you should check the relevant information from the oil manufacturer, and the scope of the oil should be adjusted appropriately. If necessary Such as extreme temperature, etc.).
(3) Other comprehensive performance
Due to the high working pressure of the hydraulic system of modern large hydraulic excavators (≥32MPa), the maximum working oil temperature of the hydraulic oil is also high (about 90 ° C), so in order to ensure that the hydraulic system can work normally during the normal oil exchange cycle, the hydraulic system can work normally It is required to have good quality for the lubrication, oxidation and security, resistance, abrasion resistance, anti -corrosion resistance, anti -emulsification, anti -shear stability, and polar pressure loadability of the system selected.
2. Good hydraulic oil cooling system
The improvement of the hydraulic oil heat dissipation system (more precisely as a hydraulic oil temperature control system) for large hydraulic excavators should be improved. Although the specific methods used by various manufacturers are different, the basic ideas are the same, which can make the hydraulic oil temperature temperature In the continuous operation, the balance is within an ideal range, and it can also quickly heat up the hydraulic system when investing in a cold state (reaches the normal working temperature range). Under the premise of using a qualified hydraulic oil, when hydraulic oil is overheated, the inspection steps of the hydraulic oil heat dissipation temperature control system are as follows:
(1) Whether the hydraulic oil radiator is blocked, resulting in a decline in heat dissipation efficiency, and cleaning the heat sink if necessary.
(2) Detect the actual work pressure of the system of the fan speed under extreme conditions to determine whether the hydraulic parts of the circuit have faults, oil temperature sensors or control circuits. At this time, the fan speed and the system work pressure should be the maximum; otherwise, the corresponding parameters of the system should be adjusted or replaced by the damaged element.
3. Inspection of related hydraulic parameters in the system
At present, there are two main ways to control the working pump of large hydraulic excavators: the limit load adjustment (GLR) and the load induction adjustment (LS) method of the limited load (ie, CUT-OFF function). The role of the CUT-OFF function is that when the system work pressure reaches the adjustment value, the diagonal disk corner of the variable pump is reduced, so that the pump can only be maintained in the "residual" flow status required to maintain the pressure to avoid overflowing overflowing overflowing The flow valve overflow is overheated. To achieve this, the system parameters match until the adjustment value of the Cut-OFF valve is lower than the adjustment value of the primary pressure valve in the circuit according to technical requirements; otherwise, the opening of the primary pressure valve will cause overflow overcipping.
At the same time, check whether the secondary valve work is normal. This work must be carried out strictly in accordance with technical requirements, and if necessary, the relevant parameters of the system should be restored to adjust.
4. Exclude non -normal internal leakage
It mainly refers to the non -normal internal leak caused by the direction valve and pressure valve card bite caused by the pollution of the system hydraulic oil. Methods: measure pressure, check function, or listen to whether there are abnormal noise (the "throwing sound caused by the valve port") or whether the temperature is too high.
5. Prevent component volume efficiency decreased
Pay attention to normal wear and normal wear. The former may occur within a short period of time, and can be judged by checking the quality of the oil and combining the function of the system (such as whether the action of the component is normal, whether the speed decreases, etc.); Examine and take measures in time.
