Oil leakage of slewing ring

/分类： /作者：

The slewing bearing is responsible for the operation and rotation of marine equipment, engineering machinery, light industry machinery, metallurgical machinery, medical machinery, and industrial machinery and equipment. It is an important transmission component necessary for machinery that needs to bear axial force, radial force, and tipping moment. . Therefore, the consideration of performance guarantee in the structural design of the slewing bearing cannot be said to be insufficient.

 

The rotating structure needs sufficient lubrication, and the slewing bearing is no exception. The grease lubrication of the rotating part of the bearing is divided into two cavities: the slewing bearing lubrication cavity and the rotating gear ring lubricating cavity. The lubrication of the slewing bearing is completed by adding lubricating grease to the lubricating nipple located in the outer ring of the slewing bearing, and the lubrication of the slewing ring gear is completed by pre-filled grease. The slewing bearing has two rubber strips inside and outside (or upper and lower) as oil seals. The outer oil seal is fixed on the inner ring (fixed plate) of the slewing bearing of the lower frame to prevent dust from entering the slewing bearing. The inner oil seal is located on the outer ring (moving disc) of the bearing to prevent grease in the rotary gear ring from entering the bearing.

 

However, equipment and related accessories will be affected by a variety of comprehensive factors in actual use, and abnormal phenomena are inevitable. The oil leakage of turntable bearings is one of the common failure phenomena.

 

Generally, it is normal for a small amount of oil leakage in the outer oil seal under working conditions. The so-called normal means that the amount of grease leaking through the outer seal of the slewing bearing is approximately equal to the amount of grease added to the slewing bearing. However, when an abnormal phenomenon of a large amount of grease leakage occurs on the excavator, it should be checked. Due to the particularity of the lubrication structure of the rotating part, it is necessary to analyze whether there is a leakage and determine the problem in order to solve the problem.

 

Since the grease filled in the original equipment may be incorrect, the grease will become thinner when the temperature of the slewing bearing or the slewing ring gear rises slightly. If the thinned grease is pushed to the upper section of the ring gear during the meshing process by the driving gear of the rotary motor, it will flow into the bearing cavity through the inner oil seal, and the grease will drip out from the outer oil seal.

Discuss the stability of the slewing bearing

/分类： /作者：

For equipment installed with slewing bearings, corresponding performance is the focus of users’ attention, and often requires high accuracy. In the application of equipment, the stability of the slewing bearing can meet the requirements of the special work nature of construction equipment, including bearing large axial load, radial load and overturning moment and other comprehensive loads. The following editor will discuss the stability of the slewing bearing with everyone:

In the design of accessories, the rolling elements are usually separated by separate blocks. This structure can maintain the smoothness of movement, so it is widely used. Special applications require special ball or roller spacers. Bearings installed on horizontal shafts or continuously rotating generators and bearings used in occasions with high requirements for positioning and reliability can use strip combined cages to keep the rolling elements in the correct circumferential position .

The purpose of using cages for slewing bearings is very clear: improve bearing rotation performance and efficiency, consolidate bearing stability and reliability, improve bearing design life and service life, and solve the problems of uniform force and bearing structure under complex working conditions . Integral cage-segmented cage-copper cage-steel cage-polyurethane cage-nylon cage-polytetrafluoroethylene cage-PA cage, and composite material cage.

 

Slewing bearing

 

In addition, for slewing bearings, stability and reliability are the two core indicators considered in the selection and design of slewing bearings. The main process design considerations are: structure; material; modulation hardness and quenching hardness; bearing rolling elements and The height and wall thickness ratio of the ferrule; machining accuracy; the material, structure and type of the cage, such as the integral cage, can obviously improve the rotation performance and life of the bearing; the lubrication system and the sealing system; the level of installation and debugging; the daily maintenance Frequency; application of mature design.

In order to ensure the stability of construction equipment, the design of slewing bearings pays more attention to the rationality of the structural configuration, but in many cases, gear teeth can be machined on the inner or outer ring of the bearing to simplify the structure of the drive system. In order to avoid problems, when determining the structure of the drive system, you should seek the help of relevant personnel in the gear.

The above is the discussion about the stability of the slewing bearing. The design of pipe fittings pursues higher performance, but in actual applications, once installation, use or maintenance is improper, various problems may arise, such as in the slewing bearing. There was a problem of excessive shaking during use. The common causes of this are loose installation bolts, causing shaking during work; insufficient rigidity of the steel structure supporting the slewing bearing, elastic deformation during loading, resulting in overall shaking of the slewing bearing, etc., in order to ensure the normal use of the slewing bearing, if you If there is shaking in the machine, it is necessary to stop the machine for inspection in time to prevent long-term shaking from causing greater damage to the slewing bearing

Inspection before operation of mining machinery bearings

/分类： /作者：

After the bearing is installed, in order to ensure the smooth operation of the bearing, the inspection work before the bearing operation should be paid attention to.

For small machines, you can directly rotate the bearing by hand to see if it can run smoothly. In daily inspection operations, common poor operation phenomena mainly include: poor operation due to foreign objects, scars and indentations; poor operation due to improper installation; large installation errors due to too small clearance, etc. The reason is that the torque is too large, resulting in poor operation of the bearing, etc. If no abnormality is found after careful inspection, the bearing can be used for the next step of power operation.

For large machinery, manual rotation is not possible, but inertial operation can be carried out by stopping the power in time after starting without load, and then carefully observing the vibration and noise of the bearing and the actual contact of each rotating part to confirm that there is no After the abnormality, the next power rotation stage can be carried out.

Power rotation, this stage generally starts from the no-load low-speed stage and gradually increases to the rated operating speed. During the trial operation stage, the focus should be on checking: whether there is abnormal sound in the bearing, whether there is lubricant leakage, and whether the bearing has a large temperature rise change, etc. If an abnormality occurs during the trial operation of the bearing, the bearing should be carefully inspected even if the operation is stopped, and the bearing should be disassembled and inspected if necessary.

The temperature rise of the bearing can usually be known by inspecting the bearing housing, but it is also possible to directly inspect the temperature of the outer ring of the bearing with the aid of the oil filling hole, so that the inspection result obtained will be more accurate. The bearing temperature of mining machinery generally rises gradually from the beginning of the bearing operation, and the bearing temperature usually tends to stabilize after rising to a certain temperature. If the bearing is installed improperly, it may cause the bearing temperature to rise sharply and produce abnormal temperature rise. In addition, excessive bearing lubricant, too small internal free gap, severe wear of the ball, high-speed rotation, etc., may also cause a transitional temperature rise of the bearing.