Regarding the selection of bearing lubrication methods and the timing of bearing grease replacement

Regarding the selection of bearing lubrication methods, we have summarized the following six key principles:

1. When the operating speed and temperature rise of the bearing are within a reasonable range, we can give priority to using grease as a lubrication method.

2. Among all lubricating oil lubrication methods, drip lubrication has a higher comprehensive advantage in terms of technology and economy. Therefore, when choosing a lubrication method, we should pay enough attention to drip lubrication. If the automation system can be applied to drip lubrication to achieve more precise control, the development prospects of drip lubrication will be broader.

3. For heavy-loaded bearings with low speed or hollow bearings with high speed, we can choose pressure circulation lubrication to ensure sufficient lubrication of the bearings.

4. For high-speed light-loaded bearings, we can choose dispersed droplets or oil mist lubrication; while for high-speed heavy-loaded bearings, spray lubrication should be selected.

5. The comprehensive technical and economic indicators of splash lubrication and oil bath lubrication are low, and we should try to avoid using these two lubrication methods.

6. When selecting the lubrication method for bearings in a complete set of equipment, we should fully consider the lubrication methods and characteristics of other components, and try to use lubricants of the same model or variety to reduce operating costs and improve the overall performance of the equipment.

When is the best time to replace bearing grease?

(1) During the use of bearings, the role of grease cannot be ignored. But have you ever thought about whether grease can be used unlimitedly? When and how much grease should be replaced? These questions actually cover multiple aspects of bearing maintenance technology and are quite complex.

(2) Regarding the amount of grease used, we must be clear: unlimited use of grease is not advisable. Because excessive grease will cause many adverse effects on bearings.

(3) Grease plays a vital role in bearings, and its adhesion, wear resistance, temperature resistance, rust resistance and lubricity are all excellent. It can enhance high-temperature oxidation resistance, delay the aging process, dissolve carbon deposits, prevent the accumulation of metal eyebrows and oil stains, thereby improving the wear resistance, pressure resistance and corrosion resistance of the machine.

(4) However, when the amount of grease filled is too much, the friction torque will increase accordingly. At the same filling amount, the friction torque of sealed bearings is usually greater than that of open bearings. When the grease filling volume reaches about 60% of the internal space volume of the bearing, the growth trend of the friction torque will tend to be flat. This is because most of the grease in the open bearing has been squeezed out, while the grease in the sealed bearing may also leak.

(5) As the grease filling volume increases, the temperature of the bearing will also rise linearly. At the same filling volume, the temperature rise of the sealed bearing is usually higher than that of the open bearing. Therefore, it is generally believed that the grease filling volume of the sealed rolling bearing should not exceed about 50% of the internal space.

(6) Usually, the lubrication plan of the bearing is formulated according to time. The equipment supplier will formulate a lubrication plan based on the operating time and provide guidance on the amount of lubricant to be added in the maintenance plan. For the staff, it is normal to change the lubricant regularly, but in actual operation, it is often easy to add too much grease.