Ntn slewing bearing anti-corrosion and heat lubrication method



Improper ways can also cause ntn bearings to heat up. Lubrication can reduce wear during movement of parts, ensure press accuracy and reduce energy consumption. Lubrication is divided into thin oil lubrication, concentrated oil lubrication, etc. Thin oil lubrication: The advantage is that the internal friction coefficient is small, so the energy consumption against the friction is small, the thin oil has good fluidity, easy to enter the friction surface of each lubrication point, has good cooling effect, and can adhere to the friction surface. The impurities and the metal particles generated by the grinding are carried away. The disadvantage is that the oil film cannot withstand large unit pressures and has high requirements for sealing. High-speed presses are generally lubricated with large flow and thin oil, which can take away the heat generated by each friction pair.

Lubricating oil: The advantage is that it is easy to seal, less loss, less affected by temperature, and has a large adaptability to changes in load properties and movement speed. The disadvantage is that the fluidity is poor, the internal friction coefficient is large, so the energy loss is large, and the lubrication performance is lost when working at a high temperature for a long time. In order to improve the properties of the concentrated oil, 15% to 30% mechanical oil is often added to the grease.

The lubricating oil has high viscosity, large bearing capacity, bearing flow rate / J, and high power consumption, so the bearing temperature rises. The temperature is high and the viscosity of the lubricating oil is lowered, so that the viscosity of the lubricating oil is increased to increase the load carrying capacity of the ntn bearing.

Grease is very important with slewing bearings. The use of deteriorated grease not only does not function as expected, but also damages the bearing.

1. Oil flow observation method

Take two measuring cups, one of which is filled with the lubricating oil to be inspected, the other is placed on the table, and the measuring cup filled with lubricating oil is lifted off the table 30-40 cm and tilted to allow the lubricating oil to slowly flow to the empty cup. In the middle, observe the flow, the quality of the lubricating oil flow should be slender, even, continuous, if the oil flow suddenly and slowly, and sometimes there is a large flow, then the lubricant has deteriorated.

2, handcuffs

The lubricant is rubbed repeatedly between the thumb and the index finger. The better lubricant feels lubricated, less wear debris, and no friction. If you feel a large friction between the fingers, it means lubricating oil. There are many impurities inside, and new lubricant should be replaced.

3, lighting method

On a clear day, use a screwdriver to pry the lubricant at a 45-degree angle to the horizontal. In view of the sunlight, observe the oil droplets. Under the light, it can be clearly seen that there is no wear debris in the lubricating oil, which can be used continuously. If the grinding debris is too much, the lubricating oil should be replaced.

4, oil droplet trace method

Take a clean white filter paper, drop a few drops of oil on the filter paper. After the oil leaks, if there is black powder on the surface, touch the hand with a feeling of resistance, it means that there are many impurities in the lubricant, good lubricant No powder, it is dry and smooth by hand, and it has yellow marks.
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Principles for the use of grease in TIMKEN bearings



Lubrication is an important part of the use of TIMKEN bearings. Therefore, many people think that the more grease is used, the better the bearing, but it is not. There is also a degree of grease used.

The general grease filling amount in TIMKEN bearings can refer to the following principles:

(1) The general bearing should not be filled with grease to fit 1/2-3/4 of the entire space of the bearing cavity;

(2) 2/3-3/4 of the horizontal bearing filling the inner cavity space;

(3) The vertically mounted bearing fills 1/2 (upper side) of the inner space of the cavity, 3/4 (lower side);

(4) In the environment of easy pollution, for the bearings of low or medium speed, fill the entire space in the bearing and bearing box;

(5) High-speed bearings should be placed in high-quality lubricating oil before loading. Generally, it should be soaked in the base oil of the installed grease to avoid bearing burnout caused by insufficient lubricating oil on the friction surface during starting.

TIMKEN bearing greases are usually expressed in terms of apparent viscosity or similar viscosity. When describing the viscosity of the grease, the temperature and shear rate must be specified. Similar viscosity indicators can be used to control its low temperature fluidity and pumpability.

One of the important indicators to measure the low temperature performance of TIMKEN bearing grease is the low temperature torque, that is, the degree of rotation of the low speed flow bearing at low temperature (below -20 ° c). The low temperature torque of the grease is determined by the starting torque and The average value of the torque after turning 60 mm is indicated.

The evaporability (degree) of TIMKEN bearing grease indicates the degree of volatilization of the grease when the grease is used for a long period of time under high temperature conditions. The smaller the evaporability, the better. The evaporability of the fat depends primarily on the nature of the lubricating oil and the fraction composition.

Oxidation stability refers to the ability of grease to resist heat and oxygen when used for long-term storage or long-term high temperature, maintaining its ability to not permanently change. Due to oxidation, the free base content is reduced or the free organic acid content is increased, the dropping point is lowered, the appearance color is deepened, the odor is exhibited, the consistency, the strength limit, the similar viscosity is decreased, the corrosive product is formed, and the structure of the grease is broken. Substance, causing the separation of soap oil. Therefore, in the long-term storage of grease, it should be stored in a dry and ventilated environment to prevent exposure to sunlight, and regular changes should be made to the changes of free alkali or free organic acid, corrosive and other items to ensure its quality and performance.
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