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Slewing bearings are widely used in excavators. Recently, many friends have come to inquire about the oil leakage of excavator slewing bearings. Today, the editor will talk about how to deal with it, and share the experience of repairing and handling.

 

When the excavator is in use, lubricating oil often leaks out of the bearings, and the leaked oil and butter mix together and it is difficult to distinguish the type! How can I tell which oil is leaking out?

 

The first step is to check whether the gear oil level of the rotary gear box is lower limit or high tide. If the gear oil level drops or there is basically no oil level, it can be directly determined that the grinding disc oil seal under the rotary gear box is damaged.

 

Remedy: Check whether the reduction gear box gear is damaged. If the reduction gear is normal, check whether the clearance between the upper and lower bearings of the rotary vertical shaft or the bearing seat is too large. If there is any problem, replace the bearing or repair the bearing seat shell! Check whether the contact surface between the oil seal and the vertical shaft is severely worn. If necessary, cut the oil seal lip spring appropriately to increase the tightness of the oil seal or change the position of the oil seal lip!

 

If the oil level in the rotary tooth box increases significantly, it can basically be concluded that the oil seal of the rotary motor skeleton is damaged, because the hydraulic oil in the motor is connected to the tooth box through the pressure to the lower tooth box. The pressure in the tooth box is too high to damage the oil seal of the grinding disc, so the motor skeleton must be replaced at the same time And the grinding disc oil seal! When disassembling the motor, carefully check whether the bearing of the upper cover of the motor shaft is too large, which causes the centrifugal rotation of the motor shaft to rotate and damage the oil seal!

 

If the oil level in the rotary tooth box is normal, then the oil seal of the rotary center joint is damaged! The most obvious symptom is insufficient power to walk on one or both sides!

 

Remedy: Replace the oil seal inside, and check whether the contact surface of the first oil seal on the shaft is worn! If the abrasion is severe, it must be repaired. If it is not repaired, it will be futile even if the oil seal is replaced. Because the cost of replacing the shaft is too high, it is usually repaired, and it can be used normally after the sleeve or repair welding and then polishing.

 

If the above three causes are eliminated, there is another possibility that the sealing ring of the main support bearing of the slewing ring is damaged! The only thing that leaked out was the butter, because the viscosity of the butter was relatively high and it was easy to distinguish it.

 

Some friends think that you don’t like to miss some butter, so they don’t pay much attention to it! But here to tell everyone that this oil seal not only plays a role in sealing oil, but also plays a role in dust prevention! Because most of the working environment of the excavator is in the sand and rock field, it is inevitable that debris will be mixed into the bearing to cause early wear of the slewing bearing, which directly affects the service life of the turntable! Although it is troublesome to replace, it is recommended to replace it in time for your car.

Slewing Bearing
Bucket wheel machine is an important production equipment that needs to be used during the transportation and loading and unloading of bulk cargo such as coal. The main purpose is to take materials from the storage yard. It is mainly composed of cantilever arm frame structure, mast structure, counterweight beam structure, cart structure, slewing mechanism, luffing mechanism, and walking mechanism. The slewing support is mainly used to support the upper structure of the bucket wheel reclaimer. The key component of bucket wheel reclaimer rotation work. In the internal structure of the bucket wheel reclaimer, the slewing bearing occupies a large part of the area. Because of its large volume and located at the upper and lower joints of the bucket wheel machine, the failure rate is high during the working process. Today, the editor will analyze the reasons for the failure of the bucket wheel slewing ring.

1. The main failure of bucket wheel reclaimer slewing bearing

Common failures of bucket wheel slewing ring can be summarized into two categories

1. The first category is caused by improper design, manufacturing and installation.

2. The other category is acquired problems caused by improper operation, use, and maintenance after production. The problems caused by acquired problems account for a larger proportion.

Bucket wheel slewing ring

2. The cause of the failure

1. In the manufacturing and processing of bucket wheel machines, in order to save processing and material costs, there is a problem that the main shaft is too thin, which causes the large shaft to easily break at the diameter of the driving wheel. In the processing of bucket teeth, manganese steel plates are used, which directly leads to the reduction of the service life of bucket teeth to one year.

2. If the installation is not in place, it will directly lead to the frequent tearing of the cantilever belt of the rotating mechanism, damage to the roller deflection of the walking device and other faults, which brings safety risks to the safe and stable operation of the equipment.

3. During the running-in period of the slewing ring, the lubrication status is poor, and frequent full-load work results in poor running-in of the raceway and rolling element pairs, which is manifested in the early excessive wear and fatigue pitting.

4. Fatigue type failure is a common failure of slewing bearing failure. When the rolling element and the raceway are under load and are in relative motion at the same time, under the action of this alternating load, the internal micro-cracks gradually expand to the surface and form flaking. Fatigue spalling will cause shocks during the operation of the slewing ring, aggravating vibration and noise.

5. The rolling elements are worn and broken, and the raceway is seriously deformed. Under the action of instantaneous large load, the raceway is locally deformed, which directly causes the wear, deformation and even rupture of the rolling elements, thereby causing the slewing ring to fail.

6. ​​The slewing bearing fixing bolts are installed too loosely, and they vibrate and disappear in the budding state during operation.

The above is a simple analysis of the cause of the failure of the bucket wheel slewing ring. For bucket turbines, once the slewing ring fails, the entire equipment can only be stopped, which affects the entire reclaiming process of the yard and causes greater economic losses. Therefore, we must analyze the common failure causes of the bucket wheel slewing ring operation, and study effective countermeasures to reduce the sudden failure of the slewing ring causing the bucket wheel to stop abnormally.

Slewing bearings are important parts in many modern machinery and equipment, because their performance is more unique than other mechanical parts, including significant advantages in anti-corrosion performance. However, if the slewing bearing is not produced in strict accordance with the cleaning and anti-rust regulations and the requirements of the oil seal and anti-rust packaging, the bearing parts in the processing process and the finished bearing products after assembly shall be treated with rust; or the anti-rust used in production The quality of rust lubricating oil, cleaning kerosene and other products cannot meet the requirements of the process technology, and the use of inferior anti-rust lubricating oil will cause the bearing to rust. So what can be done to prevent it from rusting? Today, the editor will share with you several ways to prevent the rust of turntable bearings.

1. Surface cleaning method

Cleaning must be based on the nature of the surface of the rust-prevented material and the prevailing conditions, and an appropriate method must be selected. Generally, there are solvent cleaning method, chemical treatment cleaning method and mechanical cleaning method. When the surface is dry and cleaned, it can be dried with filtered dry compressed air, or dried with a dryer at 120~170℃, or dried with clean gauze.

2. Method of applying anti-rust oil

1. Brushing method

This method is suitable for slewing bearings or special-shaped bearings that are not suitable for immersion or spraying. When brushing, it is necessary to pay attention not to produce anti-rust oil accumulation, and of course to prevent leakage.
Slewing ring
2, spray method

Some large slewing bearings cannot be oiled by immersion method, generally use about 0.7Mpa pressure filtered compressed air to spray in clean air. The spray method is suitable for solvent-diluted anti-rust oil or thin-layer anti-rust oil, but complete fire protection and labor protection measures must be adopted. This method is mostly used for rust prevention of some large slewing bearings.

3, soaking method

The slewing bearing is soaked in anti-rust grease, and a thick layer of anti-rust grease can be adhered to its surface. The thickness of the oil film can be achieved by controlling the temperature or viscosity of the anti-rust grease, and this layer of grease can effectively isolate it from The contact of air achieves the effect of rust prevention.

The above are several ways to prevent rusty slewing bearings. I hope everyone can help after reading them. In addition, when we use the bearing, do not directly touch the bearing with your hands, because when sweat contacts the bearing, a layer of sweat film will be formed on the bearing surface. The sweat film will cause electrochemical effects on the bearing and corrode the bearing. Therefore, use special tools such as special gloves or finger cots to pick up the bearing, and do not touch it directly with your hands.

Slewing bearings are important parts in many modern machinery and equipment, because their performance is more unique than other mechanical parts, including significant advantages in anti-corrosion performance. However, if the slewing bearing is not produced in strict accordance with the cleaning and anti-rust regulations and the requirements of the oil seal and anti-rust packaging, the bearing parts in the processing process and the finished bearing products after assembly shall be treated with rust; or the anti-rust used in production. The quality of products such as rust lubricating oil and cleaning kerosene does not meet the requirements of the technical regulations, and the use of inferior anti-rust lubricating oil will cause the bearing to rust. So what can be done to prevent it from rusting? Today, the editor will share with you several ways to prevent the rust of turntable bearings.

　　

　　 1. Surface cleaning method

　　

　　Cleaning must be based on the nature of the surface of the rust-prevented material and the prevailing conditions, and an appropriate method must be selected. Commonly used are solvent cleaning method, chemical treatment cleaning method and mechanical cleaning method. When the surface is dry and clean, it can be dried with filtered dry compressed air, or dried with a dryer at 120~170℃, or dried with clean gauze.

　　

　　 2. Method of applying anti-rust oil

　　

　　 1. Brushing method

　　

　　This method is suitable for slewing bearings or special-shaped bearings that are not suitable for immersion or spraying. When brushing, it is necessary to pay attention not to accumulate rust prevention oil, and of course to prevent leakage.

Slewing ring 

　　2, spray method

　　

　　Some large slewing bearings cannot be oiled by the immersion method, and generally use filtered compressed air with a pressure of about 0.7Mpa to spray in a clean air place. The spray method is suitable for solvent-diluted anti-rust oil or thin-layer anti-rust oil, but complete fire protection and labor protection measures must be adopted. This method is mostly used for rust prevention of some large slewing bearings.

　　

　　3, soaking method

　　

The slewing bearing is soaked in anti-rust grease, and a thick layer of anti-rust grease can be adhered to its surface. The thickness of the oil film can be achieved by controlling the temperature or viscosity of the anti-rust grease, and this layer of grease can effectively isolate it from The contact of air achieves the effect of rust prevention.

　　

　　 The above are a few ways to prevent rusting of slewing bearings. I hope everyone can help after reading them. In addition, when we use the bearing, do not directly touch the bearing with your hands, because when sweat contacts the bearing, a layer of sweat film will be formed on the bearing surface, which will cause electrochemical effects on the bearing and corrode the bearing. Therefore, use special tools such as special gloves or finger cots to pick up the bearing, and do not touch it directly with your hands.