FAG machine tool spindle bearing friction and temperature rise friction The friction of rolling bearings consists of several parts, see table. Due to many influencing factors, such as changes in speed and dynamic load, misalignment and deflection caused by assembly, the actual friction torque and friction values u200bu200bmay deviate greatly from the calculated values. If friction torque is an important design factor, please contact the Schaeffler Group Engineering Service. Composition and influencing factors of friction Idling friction depends on the amount of lubricant, speed, operating viscosity, sealing and running-in of the bearing. Heat dissipation friction is converted into heat energy. Heat must be dissipated from the bearing. At low speeds, efficient heat dissipation can be achieved by adjacent structures. In high-speed conditions or long operating cycles, heat must be dissipated through lubrication. Lubricating oil The lubricating oil takes away part of the heat. The circulating oil with cooling device has a good effect of lubricating and dissipating heat. Grease lubrication cannot dissipate heat. Heat dissipation through the shaft and housing The effectiveness of heat dissipation through the shaft and ASAHI housing depends on the temperature difference between the bearing and surrounding structure, see Figure 1. The sources of heat or heat radiation from adjacent structures must be considered. Factors affecting friction composition Rolling friction Sliding friction of the rolling elements, sliding friction of the cage Sliding friction of the cage Sliding friction of the cage Rotation speed and lubrication condition, running-in condition Fluid friction (flow resistance) Type of bearing and rotational speed Type of lubricant , Quantity and Working Viscosity Seal Friction ■ Type of seal and seal preload Figure 1 Temperature distribution between bearing, shaft and housing. Friction calculation In addition to knowing the speed and load, the type of lubrication, the lubrication method and the viscosity of the lubricant at operating temperature are important factors for further calculations. Total frictional torque MR: Frictional power NR: Frictional torque is a function of rotational speed For cylindrical roller bearings, the frictional torque is a function of load: For ball bearings, tapered roller bearings and spherical roller bearings, the frictional torque is a function of load: MR Nmm total friction torque M0 Nmm friction torque as a function of speed M1 Nmm friction torque as a function of load NR W friction power n min1 operating speed f0 Speed u200bu200bparameters for bearing friction torque, see page 15, table mm2s1 Lubrication at operating temperature The kinematic viscosity of the agent. The viscosity of the grease depends on the viscosity of the base oil at the operating temperature dM mm average bearing diameter (d + D)/2f1 Load factor for bearing friction torque, see page 15, table Fr, Fa N for TORRINGTON radial bearings is dia. Axial load, for a thrust bearing is an axial load P1 N friction torque determines the load. Ball, tapered and spherical roller bearings, see table, page 16. Bearing factors Bearing factors f0 and f1 are average values u200bu200bobtained from a series of tests and corresponding data in accordance with ISO 15312. Bearing factor f0 for oil injection lubrication, see table. With oil injection lubrication, the bearing coefficient f0 will increase, even for the same average bearing diameter dM, the same size of steel ball or roller length, and the same bearing section size. The wide series bearings in the table have a larger bearing factor f0 than the narrow series bearings. If radial bearings are used on vertical shafts, the actual value must be double the value in the table. This also applies to lubricating with high flow cooling oil or with excessive grease filling (exceeding the amount of grease that can be injected on one side). During the start-up phase, the bearing factor f0 of a bearing filled with fresh grease is equal to that of a bearing lubricated with an oil bath. When the grease is evenly distributed, the bearing factor f0 is halved. Bearing factor of cylindrical roller bearing with cage Bearing factor of thrust roller bearing Bearing factor of tapered roller bearing Bearing factor series of angular contact ball bearing Bearing factor f0 Bearing factor f1 Grease lubrication, oil mist lubrication Oil spray lubrication, circulating oil Lubrication NN30..-K 1.7 3 0.0002 0.0004 NNU49..-K 1.7 3 series bearing factor f0 bearing factor f1 grease lubrication, oil mist lubrication, oil spray lubrication, circulating oil lubrication 811, K811 2 3 0.0015 812, K812 893, K893 894 , K894 series bearing factor f0 bearing factor f1 grease lubrication, oil mist lubrication oil spray lubrication, circulating oil lubrication f1 grease lubrication, oil mist lubrication oil spray lubrication, oil lubrication 70..-B 1.3 2 0.001 (P0/C0)0.33 719..-B 73..-B 2 3.