Home / News / Analysis of wear failure of large slewing bearing and maintenance process

News

Analysis of wear failure of large slewing bearing and maintenance process

Update:04-12-2020
Summary:

Large slewing bearings are commonly found in large mech […]

Large slewing bearings are commonly found in large mechanical equipment, such as bucket wheels. During the production and operation of this kind of large-scale equipment that is not easy to move, due to a large number of working conditions, it is inevitable that parts will fail. The large-scale slewing bearing is an important part of the bucket turbine, and the slewing bearing wear is common during work. A kind of malfunction.

1. Wear condition of large slewing bearings

When the bucket wheel machine is being repaired, the overhaul of the slewing bearing is an important part. During the overhaul, it is found that the lubrication system is very poor, the sealing condition is not good, and there is residue entering the bearing track, and at the same time, the roller contact position is a little bit like, and Ring-shaped wear marks,

2. Analysis of the causes of slewing bearing wear

The large slewing bearing in the bucket wheel machine bears a relatively large load strength, and long-term operation will bring great damage to the bearing. The reasons for the failure of the slewing bearing during the working process of the bucket wheel machine are probably as follows:

(1) The slewing bearing of the bucket wheel machine has been used for a long time, and there are some minor problems in the maintenance process that have not been taken seriously. A long time will cause the accumulation of problems and eventually cause major failures;

(2) During the working process of the bucket wheel machine, the overhaul and maintenance work was not timely, so that some minor problems in the working process of the bucket wheel machine were not reported in time for maintenance, and the maintenance and cleaning work of the bucket wheel machine was not in place, which made the bucket wheel machine slewing bearing There is a lot of dust inside, which affects the rotation of the bearing and causes failure of the slewing bearing;

(3) During the transfer process of the bucket wheel machine, the overload of the transported goods will damage the working performance of the bucket wheel machine and cause the bucket wheel machine work failure.

 

 

3. Maintenance steps of bucket wheel slewing bearing

For mechanical equipment that is large and difficult to carry, such as bucket wheel machine, when it fails, it must be prepared for maintenance work when it is determined to be overhauled. Bucket wheel machine is different from other small mechanical equipment and is not well overhauled. The time can be extended to continue the maintenance. It cannot leave the transfer work for too long. If the transfer work of the power plant and terminal is left for too long, it will face the threat of paralysis. The introduction of new bucket turbines is not practical in most cases. Therefore, it can only shorten the maintenance time, but also make preparations before the maintenance.

(1) Preparation work before overhaul of slewing bearing of bucket turbine

First, the slewing bearing of the bucket wheel machine that failed is jacked up by a hydraulic jack, so that the horizontal shaft of the slewing bearing can be drawn out for inspection and maintenance. When using a jack to lift the slewing bearing, pay attention to fixing the base of the jack to avoid the jack skew and cause the slewing bearing to collapse and cause serious accidents. Therefore, in the preparation process, the jack is fixed, and then a stable support or pier is established as needed. The supporting work pieces such as columns must be guaranteed to be repaired before the bucket turbine is put into work. The built supports and piers do not affect its normal operation. The built supports and piers do not need to be dismantled. They are reserved for future bucket turbine troubleshooting. , It saves both cost and time.

(2) Carry out disassembly and maintenance work

After the bracket for the bucket wheel machine is established, the disassembly process must be carried out. It is necessary to ensure that there is enough space around the maintenance to store the disassembled parts of the bucket wheel machine. The walking wheel must be fixed with a stable steel clip to prevent it from shaking. 1. Remove the coal falling tube, central cable, and the inner and outer protective covers of the gears of the bucket turbine and release the oil in the oil tank, open the oil tank to remove the bearing bolts, and take out the slewing bearing through the workpiece established in the preparation work to troubleshoot it Analyze and repair.

(3) Installation work of slewing bearing

Install the repaired slewing bearing on the bucket turbine. During the installation process, check the connecting bolts of the inner and outer rings of the slewing bearing strictly. For the bolts that do not meet the safety requirements, they must be replaced with new ones that meet the safety requirements and pass the qualification inspection. Installation is carried out later. For the oil tank with thin steel plate, in order to ensure the toughness of the oil tank,

Try to replace it with a new oil tank after opening, because the welded oil tank is prone to failure after long-term use. In order to avoid secondary failures, replace the oil tank with a new one as much as possible to reduce the number of bucket turbine failures. When putting the installed bucket wheel into operation again, it is necessary to conduct a trial run first, and then it can be put into work after being qualified.

4. Matters needing attention when overhauling slewing bearings

First of all, pay attention to the lubrication effect of the bearing raceway during the overhaul of the slewing bearing. For a huge slewing bearing, if the lubrication effect of the long and narrow raceway is not good, it will not only be long

The dust accumulated in the raceway will affect the operation of the bearing. The lubricating oil added to the raceway is also difficult to achieve its due effect. In this way, even if the slewing bearing is repaired, it will be lubricated by the raceway when it is put into use. If the effect is not good, the bearing will be worn again, and the bearing will fail after a long time. Therefore, we must pay attention to the lubrication and cleaning of the bearing raceway, pay attention to the method of adding lubricating grease, and minimize the wear of the bearing.

Secondly, the wear of the slewing bearing of the bucket wheel machine. In addition to the effect of the lubrication of the raceway, the upper body of the bucket wheel machine has a deviation in the balance torque, which makes the wear of the bearing in the raceway more serious. Therefore, pay attention to the upper part of the body during maintenance. Heavy correction to reduce the deviation of the balance torque of the upper body of the bucket wheel.

Finally, pay attention to the installation of the partial tempering belts of the inner and outer rings of the bearing. The tempering belts of the inner and outer rings must not be overlapped and installed. They must be installed staggered to reduce the bearing capacity of the bearing and reduce the wear of the tempering belts during the operation of the bearing.

https://www.cnzxzc.com/

0
Views: 307