​How much lubricating grease you put in bearing?

Grease is widely used in bearings, motors and certain gears. It is not for bearing grease, motor grease and gear grease. Each type of grease is divided into many small types. Today we will discuss how much grease to add? It seems that everyone understands that the grease is less and the lubrication is not enough, and this has caused a misunderstanding: add more, and more. In fact, it is not good to add more grease. Let's discuss together, how much grease should be added? What's the harm in adding more?

Too much grease has the following hazards: the temperature rises during operation, which causes sealing problems, increases energy consumption, and is not good for the grease itself. For example, if the motor is added with more grease, the power consumption will increase, and in serious cases, it will cause the motor to malfunction.

Take the bearing as an example. Excessive grease is violently stirred in the bearing cavity, which increases bearing rotation resistance, and increases temperature and energy consumption. The increase in temperature will also cause the oxidation of grease to increase (premature deterioration and shortened service life). The increase in temperature causes the base oil contained in the grease to accelerate the precipitation-and the grease can play a lubricating effect, mainly because of the oil contained in it. After the base oil is lost from the grease, the thickening agent is left, which will dry and harden, causing the newly added grease to not fully flow to the bearing core, resulting in poor lubrication, bearing wear and even failure. In addition, hard blocks of dry grease may fall off, break, and then be carried into the bearing.

Too much grease will also cause sealing problems. The pressure on the seals will increase, causing the seal to rupture and fail, resulting in a weak seal, introducing impurities and permeable water, and causing damage to the bearing. Pay attention to the pressure of the seal when using a grease gun for grease. Some grease guns can reach a pressure of 15,000 psi, while a general lip seal can withstand about 500 psi. Therefore, the pressure of the grease gun should be properly controlled when greased.

For motors, the harmful effects of extra grease are similar to bearings, but there is also a possible consequence of excessive grease leakage to the motor windings, drying on the surface, resulting in poor heat dissipation of the windings.

Add proper amount of grease.

The picture shows too much grease put in the bearing

How to prevent excessive grease? First, determine the reasonable amount of grease. In addition, work out the operating specifications for the amount of grease to be added. After adding or replacing the grease, pay attention to temperature, noise, vibration, etc., and pay attention to whether there is oil leakage. For important equipment, you can also use some special monitoring tools. Such as Pneumatic grease machine.

Specify the reasonable amount of grease:

The grease quantity of the bearing can refer to this formula: G = 0.005 DB

Here: G = grease weight, grams D = bearing outer diameter, mm B = bearing width, mm or G = 0.114 DB Here, D and B use inch (inch) units.

If you use a grease gun to add grease, you should calculate how much grease the grease gun can deliver each time. You can use an electronic scale, use the lieutenant colonel to make the grease gun, and calculate how many times you need to hit the grease gun.

How to prevent excessive addition of grease?

·In addition to knowing the amount of grease added, certain methods can also help prevent excessive grease:

· When adding fat, if you feel the addition is difficult, the addition is blocked, or you start to feel a large reaction force, you should stop adding the fat.

· When adding grease, the grease outlet should be kept unobstructed to prevent the dry grease from blocking the pores.

· If necessary, some small accessories can also have a very convenient effect, such as grease gun pressure gauge, grease nipple with pressure relief function and so on.

Adding grease slowly, too fast or too fast can easily cause sealing problems, and it is not conducive to the uniform distribution of grease in the bearing.

Teach you how to choose grease

1. Grease index

Grease is a thick paste made by adding soap to lubricating oil. Commonly used are calcium-based grease, sodium-based grease, and lithium-based grease. Lubricating grease has poor fluidity, high friction loss, and unstable properties. It is only suitable for occasions where the requirements of non-liquid lubricating bearings are not high and the oil supply is unchanged.

Grease has two main indicators: penetration (or consistency) and dropping point. The degree of penetration indicates the difficulty of the grease's fluidity and the size of the internal resistance. The dropping point refers to the lowest temperature value when the grease starts to drip from the standard measuring cup for the first time.

2. The principle of choosing lubricating grease

1) When the equipment speed is low, the grease with small penetration should be selected, otherwise, the grease with high penetration should be selected;

2) Choose suitable grease according to the working temperature of the equipment. Generally, the dropping point temperature of the grease should be 15-20℃ lower than the working temperature of the equipment;

3) Calcium-based grease should be used when working in a humid environment; sodium-based grease and high tempearture grease should be used when working at higher temperatures.

3. The difference between grease and lubricating oil

1) Grease generally has higher load bearing capacity and better damping (shock absorption).

2) Grease has a lower evaporation rate than lubricating oil, so it has better lubricity.

3) Lubricating grease is not easy to pollute the equipment and work site due to its poor fluidity after being attached to the friction surface of the parts, and it can also play a role in preventing corrosion of the equipment.

4) Lubricating grease plays a sealing role, can prevent the intrusion of moisture, dust and other impurities in the air, and can reduce the design and manufacture of complex sealing devices and oil supply systems.

5) The cooling performance of grease is worse than that of lubricating oil.

4. Solid lubricants

There are powdered solids such as graphite grease, molybdenum disulfide grease, and polytetrafluoroethylene grease, and the powder is bonded or sprayed on the surface of the equipment parts during use. Flexible and convenient, solid lubricants are generally used in working environments where extremely heavy loads, extremely low speeds, extremely high and low temperatures and products are not allowed to be polluted.