In practical applications, it is very important to use an appropriate amount of grease. Generally, the inner space of the bearing should be filled with grease about one-third to one-half. Less grease will result in insufficient bearing lubrication, and too much grease will cause eddy currents. Both of these conditions will cause excessive heating and cause temperature rise. When the temperature of the grease rises, the viscosity will drop and the grease will become thinner. This will weaken the lubrication effect, and will also increase the loss of grease in the bearing. It may also cause the separation of grease components and lead to grease failure. As the grease fails, the bearing torque will increase. When too much grease forms a vortex, the torque may also increase due to the resistance generated by the grease. In order to get the best results, it is best to have enough space in the bearing housing so that the excess grease can be thrown out from the bearing. However, the grease around the bearing is also important. If there is a large gap between the bearing types, the grease should be sealed to prevent the grease from flowing out of the bearing area. Only in low-speed applications, can the bearing seat be filled with grease. When the sealing measures are not enough to exclude contaminants or moisture, this lubrication method can prevent the entry of external impurities. When the equipment is not in operation, it is wise to completely fill the bearing housing with grease to protect the bearing surface. Before the next operation, remove the excess grease and restore the proper amount. Grease equipment should have grease filling holes and ventilation holes at the opposite ends of the top of the bearing housing. There should be a drain plug at the bottom of the bearing seat to drain the aging grease from the bearing. The bearings should be lubricated regularly to prevent damage to the bearings. However, the lubrication interval is difficult to determine. If you do not have the corresponding experience, please consult your lubricant supplier. Timken can provide a variety of lubricants that can help bearings and related components operate effectively in harsh industrial working environments. High temperature, wear resistance and waterproof additives can provide better protection for bearings in harsh environments. Timken also offers a series of single-point and multi-point lubricators to simplify grease filling. Grease application method Generally speaking, in industrial bearing lubrication applications, grease is easier to use than lubricating oil. Most bearings, after the initial application of grease, need to be relubricated regularly in order to work efficiently. Grease should be filled into the bearing so that it enters between the rolling elements and raceways. For tapered roller bearings, squeezing grease from the large end surface of the bearing into the small end surface can ensure uniform distribution of lubricant. For small and medium-sized bearings, it is easier to fill the lubricant by hand (Figure 14). In workshops where grease is frequently added to the bearings, a mechanical grease filling machine should be used to squeeze the grease into the bearings (Figure 15). No matter which method is used, after the grease fills the inner area of u200bu200bthe bearing, apply a small amount of grease to the outside of the rolling elements. For any application, the two main considerations for determining the relubrication cycle are operating temperature and sealing effect. Obviously, a leak in the seal will cause frequent relubrication. Every effort should be made to maintain the seal at the highest performance. Whenever the amount of grease in the bearing drops below the required amount of grease, grease should be added immediately. When the lubrication performance is reduced due to pollution, high temperature, moisture, oxidation or other factors, the grease should be replaced. For more information about the appropriate period for adding lubricant, please consult the equipment manufacturer or Timken representative. Figure 14. Grease can be easily filled by hand. Figure 15. Mechanical grease filling machine. The consistency of a semi-fluid grease that is never thicker than a viscous oil, to a solid grease that is almost as hard as cork, varies in consistency. The consistency can be measured with a needle-type viscometer, and a standard weight cone is used to sink into the grease. The penetration distance of the cone (measured in tenths of a millimeter in a specified time) is the penetration degree. The National Lubricating Grease Association (NLGI) classification of grease consistency is as follows: Table 30. NLGI Classification NLGI Grease Grade Penetration 0 355-3851 310-3402 265-2953 220-2504 175-2055 130-1606 85-115 The consistency of grease is not static. When grease is cut or processed, it usually becomes soft (thin). In the laboratory, the above-mentioned processing involves pushing a perforated plate up and down to pass through the grease in a closed can. This processing is not comparable to the violent shear force that occurs in ball bearings, and it may not be related to actual performance.