Crane bearing and the ship crane bearing technical characteristics comparison

Slewing bearing is bearing the heavy industry is extremely important, diameter ranging from 10cm to 10 m, almost all of the large equipment to do reciprocating circular motion.

• Wind turbine slewing bearing

  Technical features: the yaw bearing is installed on the connecting part of the tower and cabin,variable paddle bearing installed in the root and the hub of each blade connecting parts. Each wind generator with a set of yaw bearing and three sets of variable pitch bearings. Yaw, pitch bearingmaterials selected 42CrMo, heat treatment using whole quenching and tempering treatment, the raceway surface quenching. The stress situation of yaw, pitch bearing complex, but also bear theshock and vibration is relatively large, therefore, requirements of bearing can bear the impact, but also can bear larger ship loader bearing.

  Wind turbine host life requirement of 20 years, the cost of installation and bearing large, therefore asked the yaw, pitch bearing life to reach 20 years. Bearing ring matrix hardness is 240-280HB,able to withstand shock and plastic deformation does not occur at the same time, the racewaysurface quenching hardness reaches 55-62HRC, which can increase the contact fatigue life, so as to ensure the long life of use requirements of bearing.

• The ship crane slewing bearing

The crane load bearing requirements of large, flexible rotation, relatively high speed, rotation of 270 degrees, the action to be fast, so the selection of internal tooth, double row ball slewing bearings. Crane bearing and the ship crane bearing technical characteristics comparison

•  Offshore platform crane bearing

According to the requirement of the bearing capacity of different, offshore platform crane often use four point contact ball slewing and the three row roller slewing bearing inner tooth.

Slewing bearing used in the offshore platform crane requires special material, the mechanical properties of the material to be able to ensure the safety coefficient of limit load, forging samplingCharpy impact experiment can achieve the average value of 42 J@-20 degrees C or 27J @ -40 C.Bearing finished product to Norske Veritas certification CCS.

One way bearing technology principle

A ramp and roller design

Ramp and roller one-way clutch inner diameter of the outer drum consists essentially, with the slope and the inner spring force to bear and were always in close contact with the inner and outer rings consisting of a set of rollers. As long as one of the rotating raceway on its impact on the direction of movement has become another industry, this arrangement ensures immediate and guaranteed the ability to go beyond the speed of the drive immediately from nature.

Use:

The design of the one-way truck mounted crane bearing can fit beyond, indexing and non-return of use in a variety of environments.

When used as a use beyond the one-way clutch

Slope-style, one-way roller clutch will be installed in this manner, is to go beyond the outer ring as a member. This point is very important for high-speed beyond. Beyond the use of the inner ring, acting on the roller speed is limited by the centrifugal force will cause beyond.

When used as an anti-kickback when using one-way clutch

Only rotating the inner roller ramp type one-way clutch is adapted to a relatively low speed. If the required speed is higher than the recommended speed, we recommend using the wedge-way clutch.

When used as an indexing using a one-way clutch

The outer ring is often seen as the swing elements are often seen from the inner components. Otherwise, rollers and spring inertia will cause errors, especially at high frequencies indexing. Diluted lubricant use and powerful springs provides high-speed indexing accuracy and quality of.

2, the wedge design

This wedge roughly one-way clutch retainer consists of a strong spring and bearing inner and outer rings, wedges group, wedge. Including wedge to wedge between the outer ring to roll from one track to another raceway transfer power. Wedge has both a diagonal diameter (that is, from one corner to the other on the wedge angle distance) is greater than the other one. In a relatively large cross-section to force the wedging action occurs when the relative rotation of the outer ring inner wedge greater vertical position.

3, self-locking angle

Rely mainly on the wedge wedging action between the inner and outer rings and self-locking wedge angle. The basic concept of the one-way clutch wedge wedge friction coefficient requirements drive the direction of the inner ring with sudden torque of a relationship, the friction value must be greater than the tangent of the angle of self-locking. If the conditions are unsafe, wedging will not happen.

Self-locking by the wedge angle is determined by the structure, the point on the inner and outer rings were used to wedge and its connections.

The initial design of the wedge has a very low self-locking angle to ensure the absolute binding at the beginning. With the increase, the wedge will generate a torque so that the wedge but raceway radial deflection forces, resulting in a wedge roller to a new location. Wedges are often designed with a self-locking can be gradually increased angle, and it is up to the same position from beyond the position of the maximum load marine crane bearing. Relatively large self-locking wedge angle can be reduced by producing a radial force, so long as the ultimate elongation and Brinell hardness requirement allows greater torque is transmitted.

How to prolong the service life and / or performance of mobile crane bearing ?

First of all, the lubrication is the key. Selection of proper lubrication system and high quality lubricant. Oil film lubrication oil film bearing surface due to contact with each other apart, and provide the necessary protection of corrosion and wear, and so on all rotating or reciprocating parts, especially gear and bearing, for the normal mobile crane bearing ‍operation of the lubrication oil film, indispensable. As for the splash lubrication or circulating lubrication system, oil film can transfer heat. Factory always due to improper lubrication and unnecessary stop and equipment state of deterioration. Oil supply shortage will lead to increased wear and temperature rise, resulting in excessive wear and / or bearing early failure and damage. Lubricating excessive, especially high-speed operation of the equipment, the oil stirring generate too much heat, so that oil and chemical degradation, can also cause bearing damage.

Correct lubrication, regular maintenance, can avoid the problems caused by the damage of bearing lubrication. Ensure proper lubrication should be:

• follow equipment manufacturers as the guide to the use of each machine set;

• add grease, shall be filled into the bearing part and the shell (or ring), to ensure the adequate grease into the raceway surface, the key is fully lubrication;

• should notice when bearing grease (Re-lubrication);

Indicating instrument, monitoring equipment, in order to find the signs of problems as early as possible, such as temperature fluctuations and / or abnormal high temperature;

• equipment noise or vibration;

• to observe the leakage of lubricating oil;

• regular on lubricant sampling, and see if the pollution.

Secondly, such as the need to improve the bearing performance, reasonable adjustment is very important. Assembly or installation, such as bearing internal clearance is too large or too small, or in some cases, preload is too high, may lead to the early damage and bearing life expectancy. In addition to causing downtime and costly repair, bearing assembly and improper installation may also have more negative effects, marine crane bearing such as the impact of other parts of the operation, shorten the service life etc..

According to the device manufacturer's manual, assembly, installation and maintenance, is the best way to prevent the problem. If time is tight, can push forward the adjustment device to correct or remove shim, loose tapered roller bearing group. On the other hand, bearing adjustment too tight, may lead to overheating damage, to replace the bearings. Process assembly mounting bearings must be accurate, repeatable, and after installation can be verified. You must also consider the parameters of other parts, in order to optimize the system performance.

In addition, in accordance with the requirements of OEM to use the equipment, set as the lubricating oil or grease repair project monitoring and forecasting of right, which should include the failure root cause analysis. So, even if there is a problem of the equipment, its normal running time can be greatly extended.

Correct lubrication and maintenance is the key, the correct installation and use is also indispensable, and make full use of the existing condition monitoring equipment. Do not follow the requirements of installation and maintenance will cause equipment failure, which is a hidden danger of.‍