Lubricating Oil
Ten Misunderstandings in the Use of Lubricating Oil
2022年3月19日
Grease Classification
Grease Classification
2022年3月19日

Grease for Motor Bearing

performance requirements of lubricating grease for motor bearing,Grease for Motor Bearing

(1) It has good adaptability and high and low temperature performance, and can be used indoors and outdoors, South and North.

(2) Good lubricity and wear resistance, no oil rejection, no drying, no emulsification, no loss, and the grease itself should not contain solids.

(3) The anti-oxidation performance is good. After long-term use, the appearance color and pH of the grease change little, and there is no obvious oxidation phenomenon.

(4) Good fluidity. Generally, it is required to use the temperature between – 25 ° C and 120 ° C, with small starting torque, low running torque, low power consumption and low temperature rise.

(5) It has strong rust resistance, salt spray resistance and good water resistance. It can be used in harsh working environment.

(6) The insulation grade is a, e and B, and shall not contain sulfur and chlorine extreme pressure additives.Grease for Motor Bearing

(7) Long service life, which can prolong the maintenance cycle and reduce the consumption of bearings.Grease for Motor Bearing

(8) Suitable consistency, good damping effect, can reduce the noise of motor bearing and is conducive to environmental protection.Grease for Motor Bearing

2 working principle and application method of motor bearing grease

The lubrication of motor bearings depends on the lubricating oil precipitated when the three-dimensional fiber network structure in the grease is pulled off under the action of shear, forming a lubricating film on the rotating elements, bearing seat and bearing race of the bearing.

When the bearing newly loaded with grease starts to rotate, the grease is first thrown out of the rotating element and quickly circulated and cooled in the cavity of the bearing cover. Then the lubricating grease cuts into the rotating element from the outside of the rotating bearing race. The part of the grease close to the surface of the rotating element breaks the fiber network structure under the shear action, so that a small amount of precipitated lubricating oil forms a lubricating film on the surface of the rotating element and race. The remaining part of the grease still maintains the intact fiber network structure, which plays the role of cooling and sealing.

When the bearing starts to rotate, the turbulence of lubricating grease generates friction heat, which makes the bearing temperature rise to a certain value. As shown in the figure below, the temperature of the lubricating oil in the bearing cavity gradually decreases with the rotation of the bearing cover, and then the lubricating oil gradually decreases from the bearing cavity to the seat, as shown in the figure below.Grease for Motor Bearing

Grease for Motor Bearing

From the above working principle of motor bearing grease, it can be seen that the grease in the motor bearing does not rely on the grease adhering to the metal surface for lubrication, but circulates continuously in the cavity of the bearing cover like a liquid, that is, it is continuously thrown out from the rotating element into the cavity of the bearing cover, and then continuously returned from the cavity of the bearing cover to the rotating element, so as to shear and cool repeatedly, That is to ensure that the bearing does not have abnormal temperature rise. Modern advanced bearing grease for electromechanical department must be able to operate in the bearing according to this working principle.Grease for Motor Bearing

The amount of lubricating grease filled in the motor bearing should be kept at 1 / 3 of all cavities in the bearing cover, leaving 2 / 3 space, so as to ensure that there is enough space for the lubricating grease thrown from the rotating element to return to the rotating element after fully cooling, so as to control the temperature rise. At the same time, it should be noted that the amount of grease filled should not be too small. Because the amount of grease is too small, the grease thrown from the rotating element cannot be returned from the bearing cover to the rotating element, resulting in insufficient lubrication.Grease for Motor Bearing

3 selection of grease for motor bearing

1. Domestic special grease for motor bearing

Special grease for small and medium-sized motor bearings – General lithium grease

2. Development of grease for motor bearings abroad

(1) In important equipment, it tends to use high-performance medium price grease.

(2) Polyurea based grease is an important development direction of high-performance motor grease.

(3) Compared with metal soap based grease, polyurea based grease has the following main characteristics:

A. Polyurea thickener is an organic thickener with good thermal stability. Its melting point is higher than that of metal soap. B. Polyurea thickener does not contain metal atoms, so it does not produce oxidation catalysis on base oil.

C. The grease with polyurea as thickener has the outstanding characteristics of high drop point, long high temperature life, heat resistance, good oxidation resistance, good water resistance, excellent chemical stability and radiation resistance, and good adhesion on rolling surface.

4 Effect of lubricating grease on motor bearing noise

Noise reduction is a special requirement for bearing performance of motors, fans and similar equipment. With the increasing requirements of environmental protection, reducing noise has become an important index of human living environment.

There are two main factors affecting bearing noise

The influence factors of lubricating grease on bearing noise are:

(1) Base oil

The main aspects are the design, material and manufacturing process level of the bearing, and the quality and characteristics of the lubricating grease used for the bearing.

a. Generally speaking, the viscosity is high and the noise is low. However, since the motor bearing is applied at high speed, it is inclined to use low viscosity base oil from the perspective of temperature rise and energy consumption. Therefore, the viscosity of base oil should be moderate.

b. The composition of oil is generally considered that the noise of naphthenic base oil is lower than that of paraffin base oil.

(2) Thickener

a. The greater the fiber length and width of metal soap thickener, the greater the noise.

b. Compound soap contributes to noise, so compound lithium grease is not suitable for motor bearing grease.

c. Low consistency and low noise.

d. Polyurea based grease has low noise.

(3) Impurity

a. Molybdenum disulfide, graphite and sodium nitrite will increase noise, so motor bearing grease generally does not contain these substances.

b. Any other impurities will increase the noise, so the total impurity content of motor bearing grease is strictly required.

(4) In order to keep the long-term noise of the bearing from increasing, it is required that the grease can always maintain a uniform oil film on the bearing surface during long-term use to prevent bearing scratch and wear, reduce vibration and achieve the purpose of reducing noise. Therefore, the basic requirements of lubricating grease for motor bearing are long service life at high temperature, no oxidation, good water drenching, good adhesion, low oil separation rate and good low temperature fluidity, so as to ensure that the bearing is not worn and the oil film is uniform under various working environments, so as to ensure that the noise does not increase.

5 arrow 1097 super polyurea based motor bearing grease

Arrow 1097 super polyurea based motor grease

Product Description: arrow 1097 super polyurea based motor grease is a grease for high temperature ball bearing and rolling bearing. It is prepared from deeply refined base oil and an ash free polyurea based thickener. Rolling bearings are a very good grease for motors, alternators, fans and similar industrial applications. It is specially designed for high load motors in extremely high and low ambient temperatures. This grease has high shear stability, low oil content, excellent rust prevention and oxidation resistance, and can prolong the service life of bearings under high temperature conditions. This is a low noise grease.

This grease does not contain extreme pressure additives or sulfur-containing additives that are corrosive to bronze and brass. It has good insulation and can meet the requirements of NEMA insulation grade A, B and F of motor.

Typical use:

*Motor bearing

*Full life grease for sealed bearings for various purposes

*Bearings in air conditioning equipment

*Non extreme pressure grease with high temperature and long service life required in industrial equipment

Advantages: excellent rust and corrosion resistance * excellent shear stability