When checking the rust cracks of the welding seam on the side plate of the excavator arm, it is necessary to scrape off or polish the surface paint layer and rust of the welding seam. When observing, tap the welding seam with a small hammer, and use a magnifying glass to observe if necessary. 1. Cause of cracks Reasons for cracks on the side plate of the excavator arm: including bubbles, slag inclusions and tiny cracks in the original weld. When the excavator is overloaded, tiny cracks will occur at the original weld and slowly expand: the welding rod Cracks that do not match the performance of the plate: Due to the large size of the excavator arm, it is difficult to adopt reliable and effective heating and heat preservation measures. During the operation, the vibration and impact are relatively large, and the uneven force at the welding seam causes the welding seam to crack. 2. Repair method Preparation work before welding: remove oil, paint, rust, etc. from the original weld crack with a hand grinding wheel. Use a gouging machine to cut off the weld crack, plan to the body of the side plate, and remove the hardened area of the base metal that was welded in the past. After planing, use an angle grinding wheel to smooth the incision (the inner interface is ground to form a V-shaped groove), after cleaning and pink inspection, confirm that all cracks have been found and removed. According to the existing maintenance conditions, choose Φ5mm type E5015 (J507) or E5016 (J506) electrode, bake at 350℃ for 2 hours, and then keep at 100℃ to prevent the electrode from absorbing moisture. 230A. Due to the large thickness of the side plate of the excavator, the welded part should be preheated to 150 ~ 250 ℃ before welding; during the welding process, the segmented, symmetrical and backward method can be used for welding; during the cooling process of the weld, it should be continuously used The hand hammer strikes the weld metal to relieve stress; when welding at the corner of the side plate, in order to avoid arc defects, continuous welding should be performed to improve the stress condition of the joint. After welding, thoroughly remove the spatter, welding slag and welding flash, and the residual height of the welding seam shall not be greater than 2.5mm. Magnetic particle inspection is carried out on the weld, and defects such as cracks are not allowed. 3. Weld corrosion prevention measures Thoroughly sand, derust and coat welds with anti-rust paint. At the excavation construction site, for the existing rusted welds, manual rust removal can be selected according to the actual situation. The disadvantage is that the labor intensity of workers is high and the labor cost is high; The main base is mixed with composite materials such as corrosion inhibitor, surface active agent, rust remover, rust inhibitor and film-forming agent to prepare a pickling solution with the functions of rust removal, rust prevention and primer. Rust removal and rust prevention purposes. In addition, during use, attention should also be paid to keeping the excavator in a clean and dry environment, maintaining good ventilation, and removing corrosive gases and moisture in time.

Common excavator structures include power devices, working devices, slewing mechanisms, operating mechanisms, transmission mechanisms, walking mechanisms and auxiliary facilities. The transmission mechanism transmits the power of the engine to the hydraulic motor, hydraulic cylinder and other actuators through the hydraulic pump, and pushes the working device to move, thereby completing various operations. walking device The walking device is the chassis, including the crawler frame and the walking system, which is mainly composed of the crawler frame, the walking motor + reducer and its pipeline, the driving wheel, the guide wheel, the carrier wheel, the roller, the crawler, and the tensioning buffer device. The function is to support the weight of the excavator, and convert the power transmitted by the driving wheel into traction, so as to realize the walking of the whole machine. The frame assembly (that is, the crawler walking frame assembly) is an integral welded part and adopts an X-shaped structure. Its main advantage is that it has a high bearing capacity. The frame assembly is welded by three parts: the left longitudinal beam (ie the left track frame), the main frame (ie the middle frame) and the right longitudinal beam (ie the right track frame). The weight of the frame assembly is 2 tons. The central rotary joint is a hydraulic component connecting the rotary platform and the oil circuit of the chassis. It ensures that after the rotary platform rotates at any angle, the travel motor can still distribute oil normally. The current rotary joint is 5-way. ​

The working device is the main component of the hydraulic excavator. At present, the SY series excavator is equipped with a backhoe working device, which is mainly used to excavate the soil below the parking surface, but it can also excavate the soil below the maximum cutting height. In addition to ditching and loading, it can also perform simple field leveling work. The excavation operation is suitable for excavating the soil of grade Ⅰ~Ⅳ, and the hydraulic hammer or blasting method is required for the above grade Ⅴ. The backhoe working device is composed of boom, stick, bucket, rocker, connecting rod and hydraulic pipelines of the working device including boom cylinder, stick cylinder and bucket cylinder.

1. Excavators are fixed assets with large economic investment. In order to increase their service life and obtain greater economic benefits, the equipment must be assigned personnel, machines, positions, and responsibilities. When the post must be transferred, the equipment should be disclosed. 2. After the excavator enters the construction site, the driver should first observe the geology of the working face and the surrounding environment. There should be no obstacles within the excavator's rotation radius to avoid scratches or damage to the vehicle. 3. After the machine is started, no one is allowed to stand in the bucket, on the shovel arm and on the crawler to ensure safe production. 4. When the excavator is working, it is forbidden for any person to stay or walk within the radius of gyration or under the bucket. Non-drivers are not allowed to enter the cab to tamper with, and do not train drivers to avoid damage to electrical equipment. 5. When the excavator is relocated, the driver should observe and whistle first, and then relocate to avoid safety accidents caused by someone beside the machine. The relocated position should ensure that the space of the excavator's rotation radius is free of any obstacles, and illegal operations are strictly prohibited. 6. After the work is completed, the excavator should be moved away from the low-lying place or the edge of the trench (ditch), parked on the flat ground, and the doors and windows should be closed and locked. 7. The driver must do a good job in the daily maintenance, inspection and maintenance of the equipment, keep a good daily record of the equipment in use, find that there is a problem with the vehicle and cannot operate with illness, and report the repair in time. 8. The cab must be clean and tidy, and the surface of the car body should be kept clean, free of dust and oil; after work, develop the habit of cleaning the car. 9. The driver should make a record of the daily shift in time, make statistics on the work content of the day, complete the formalities for the part-time workers or zero items outside the project in a timely manner, and make a record for the checkout. 10. Drivers are strictly prohibited from drinking at noon and driving under the influence of alcohol during the work period. If found, they will be given financial penalties and the economic losses caused will be borne by themselves. 11. For human-caused vehicle damage, it is necessary to analyze the reasons, find out the problems, distinguish the responsibilities, and impose economic penalties according to the severity of the responsibilities. 12. It is necessary to establish a high sense of responsibility, ensure safe production, conscientiously do a good job in communication and service with the construction party, improve bilateral relations, establish a good work style, and work hard for the development and efficiency of the enterprise. 13. Excavator operation is a special operation, and a special operation license is required to drive an excavator. 14. Maintenance is to follow maintenance taboos.

(1) Wear of the speed change transmission mechanism The W4-60 excavator adopts a mechanical shift transmission mechanism, which relies on the sliding tooth sleeve to move axially on the fixed tooth sleeve and is connected with the driven gear of each gear. engaged to achieve shifting. In the frequent shifting process, the tooth end faces of the above-mentioned meshing gears are easily ground into a conical shape, which reduces the meshing performance and leads to "jumping gears". (2) The performance of the self-locking mechanism is degraded. In order to prevent the transmission from "jumping", this type of excavator is installed in the box cover holes above the fork shafts of the Ⅱ, Ⅲ and Ⅳ and Ⅴ gears of the transmission and in the Ⅰ and reverse shift forks. There are steel balls and springs that play a self-locking role. When the elasticity of the spring that plays the role of positioning and self-locking is weakened or broken, the self-locking performance of the self-locking mechanism will decrease until it disappears, causing the transmission to "jump". At the same time, if the groove on the positioning steel ball or the fork shaft is worn, it can also cause the transmission to "jump". (3) Improper adjustment of the shifting device The transmission of this type of excavator adopts a mechanical manual shifting method. If the shifting lever, vertical axis, horizontal axis and vertical fixing screws are loose, the transmission can also "jump". (4) Sudden change of external load Due to the working nature of the excavator and the design of the machine itself, the sudden change of the external load will also cause its transmission to "jump". When the road surface is uneven, the machine is driving downhill or the driving route is improper and the external load changes suddenly, the sudden change of the load will act on the gear meshing gear of the transmission through the wheels and drive shaft, so that the gear meshing gear Disengagement due to axial thrust, causing the transmission to "jump". (5) Improper operation method When the excavator is driving on a slope (especially driving downhill), if the operation is improper, it will also cause the transmission to "jump".

(1) Operate in strict accordance with the operating procedures and driving essentials, and try to avoid "beating teeth" when shifting gears to reduce the wear of the gear pair. (2) Strictly implement the maintenance system and strengthen the maintenance of the shifting device. When the lever system of the shift device is not connected properly, it should be adjusted in time to ensure the good performance of the shift device. (3) Pay attention to the repair and maintenance of the self-locking mechanism. The positioning steel balls, springs and fork shafts with reduced positioning effect or loss of positioning efficiency should be repaired or replaced in time to keep the self-locking performance of the self-locking mechanism in a good state. . (4) When assembling the transmission, it should be operated in strict accordance with the operating procedures to ensure that the various parts of the transmission are properly adjusted and tightened properly. On a large downhill road, the driver should strictly follow the downhill action essentials, and must not violate the regulations.