Crane lubrication: manual crane lubrication or centralized crane lubrication?

19 Nov, 2015

The crane lubrication is an important part of crane daily maintenance. The quality of crane lubrication not only affects crane operation but also influences the working life of crane parts and components. What’s more important, it affects crane safety and operation efficiency Therefore, the crane maintenance personnel should check the lubrication condition of the crane frequently and refill the lubricant timely.

On the overhead crane, there are lots of places that needs to be lubricated. Generally, all contact surfaces of holes and shafts as well as mechanical friction surfaces requires lubrication. There are two ways for lubrication: manual decentralized lubrication and auto centralized lubrication.

Overhead crane lubrication

Manual decentralized lubrication

Manual decentralized lubrication is usually used by medium and small crane equipment. Manual lubrication is to use lubricating screw or grease cup to refuel the lubrication points separately. The manual lubrication is simple and low cost however it takes longer time for lubrication personnel to lubricate each and every lubrication points, and also, the lubrication holes are easily blocked due to the exposure to dusts. What’s more, it is risky to lubricate some lubrication points manually. Therefore, the centralized lubrication system is used.

crane lubrication

Lubrication screw and Centralizded lubrication system

Centralized lubrication system

Centralized lubrication system takes the advantage of lubrication pump. When lubrication is needed, the maintenance personnel only needs to refill the lubrication pump, and then the lubricant can be pumped to each lubricant points. It is reliable and safe. Besides, the monitoring system can be installed to monitor the lubrication condition of lubricating points. Because it does not need to stop the crane to be lubricated, the centralized lubrication system is widely used on cranes which are used in the production lines, such as, steel-making production lines, which can largely improves the working efficiency, and also provide a good working environment for the maintenance workers.

Crane lubrication positions

Same as other machinery, overhead crane’s operation must reply on the adequate lubrication; if lubricating oil failure, the overhead crane will begin to wear down. So the correct lubrication is very important to the overhead crane. Different parts’ lubrication should be checked each 2~3 month according to the different location. As for the overhead cranes working at harsh conditions, lubrication cycle should be reduced accordingly.

1. Lubricating position

The gearbox, open gear, wheel bearing, rail, motor bearing, the brake etc.

2. Here we discuss the lubrication position in detail:

Lubrication should follow the requirement of maintenance manual, different brands of lubrication oil should not be mixed.

1). Gearbox: normally oil pool should be used for lubrication, summer with N100 load gear oil or 30 gear oil, winter with N78 load gear oil or 20 gear oil.Gearbox lubrication oil amount should be often checked through oil needle or the oil cover, it is required for a timely supplement and the lubrication oil should be replaced every half year.
Gearbox Oil leakage maintenance
When operating the gearbox internal pressure is increased, so oil leakage is most frequent equipment failures, the general treatment method is:

A, the lubrication oil capacity should not exceed the upper limit

B, the deceleration vent should keep smoothly

C, Check out of the gearbox, reducer and static residual sealant on the surface of seals should be cleaned in evenly coated with sealing glue (recommended by the 601 polymer liquid sealant), to be a little glue after polymerization, and tighten the bolts in box.

D, Dynamic surface seal aging deformation or wear should be replaced in a timely manner

2). Hydraulic brake actuator: summer with 25 transformer oil, winter with No. 10 aviation oil or instrument oil.
3).The lubrication of the wire rope is made of synthetic graphite calcium base grease or other wire rope grease, and the grease is coated on the steel wire rope. Pay attention to make sure the penetration of oil entering into the wire rope.
4). Various parts of the bearing, gear coupling and open gear should be lubricated with lithium based grease, 2 in summer, winter with No. 1.
5). For joints and bolts with a slight relative movement, lubricated with calcium or lithium based grease or 45 oil.

3. Maintenance of hydraulic drive

Hydraulic drive contain with a single push rod and double push points.

A. hydraulic actuator recommended to be used with working oil

Ambient temperature >-10 degree, DB-25 transformer oil should be used.
The ambient temperature is less than or equal to -10 degrees, 10 aviation hydraulic oil should be used.

B. Refuel steps Unscrew the oil plug, slowly fueling into the working oil to the rated level, tighten the oil plug, pull up and down the push rod repeatedly several times, in order to the exclusion of the air in the cylinder, once again fueling into the oil to the rated level, then you can tighten the oil plug.

C. Replacement of working oil

Periodic inspection of working oil, refueling the oil timely, the suitable oil should be changed based on the changes of working temperature, especially for the open air working hydraulic brake, the lubrication oil replacement steps should be as follow instructions: first, remove the hydraulic actuator from the brake frame; unscrew the oil plug, inverted drive, exclude the original oil, then refueling as per the instructions.
The following issues should be focused among the hydraulic oil usage: whether the oil temperature is normal, whether there is water or impurities, observe the bubble, if the bubble is over amount, the reason should be checked.

4. Matters needing attention

1). Gearbox lubricating oil increase the amount of oil or oil needle into the upper and lower limits of calibration, not higher than the upper limit, if excessive oil spill will occur.
2). Lubricating oil should always be kept clean. If you use grease, clean up the previously used grease.
3). Regular cleaning of oil pipeline, to keep the oil path smoothly.
4). Different models, different brands of oil shall not be mixed use.
5). On above point 2 lubricating oil and grease for the recommended model specifications, customers can use the experience and the relevant information on the selection of lubricants more suitable for different occasions of lubricating oil and grease. The selection of the time to pay attention to consider the condition, load, temperature, dirt etc. If there is water at the points, sodium based grease should not be used.

If you have any problem or doubt on overhead crane, gantry crane, jib crane, or electric hoist, winch, please feel free to contact us. Dongqi Hoist and Crane is able to provide you types of cranes and related crane services.