The friction torque of ball bearings used in FYH rolling bearings is a combination of the rolling friction of rolling elements (balls) and raceway rings (outer and inner rings), the sliding friction of rolling elements and cages, the stirring resistance of lubricants, and the friction of oil seals. friction resistance. The size of the friction torque is affected by the size of the bearing, bearing load, speed and lubrication conditions. In order to improve the sealing performance of the bearing, the rolling bearing with seat adopts an oil seal with good dustproof performance, so the frictional resistance of the oil seal accounts for a large proportion of the friction torque of the bearing. The friction torque of a ball bearing for rolling bearings with a house can be calculated by the following formula. In the above formula, M : Frictional torque of bearing, mNm Mp : Frictional torque of the part that changes according to the load, mNm Mk : Frictional torque of the part that changes according to the rotation speed, mNm μ : Coefficient of friction (0.001 5 to 0.002) P : Bearing load, N d : Bearing nominal inner diameter, mm. However, it is difficult to obtain the values u200bu200bof the stirring resistance of the lubricant and the frictional resistance of the oil seal which change according to the rotation speed by calculation. Figure 13.1 shows the measurement results of the friction torque of a representative rolling bearing with a house. Example of measurement results of friction torque of FYH rolling bearing with block. The temperature rise of the bearing: The temperature rise of the ball bearing for the rolling bearing with seat is caused by the conversion of the friction torque inside the bearing into heat energy during operation. The bearing temperature during operation increases proportionally with the increase of the friction torque and the increase of the rotational speed (the friction torque increases proportionally with the increase of the bearing load). The temperature rise value of ball bearings for rolling bearings with a seat is determined by the heat generated by the internal friction of the bearing and the heat released from the surface of the bearing and bearing housing to the outside. Therefore, the temperature rise of the ball bearing for a rolling bearing with a house is affected by the state of the surroundings where the bearing with a house is mounted (the quality of the heat radiation environment). The temperature of the rolling bearing with a block rises gradually after the operation starts, and if there is no abnormality, it reaches the maximum after 1 to 2 hours, and then the temperature drops slightly and becomes a stable state (see Figure 13.2). The temperature of the bearing is almost constant unless the operating conditions change, so the state of the bearing can be estimated by measuring the temperature. An example of temperature measurement results during operation of FYH Plummer Block UCP208J. The temperature rise and friction torque of a rolling bearing with a block during operation are the same, but it varies depending on the type of oil seal used in the bearing. The temperature rise of triple seal products (symbol L3) is larger than that of ordinary products, and the temperature rise of non-contact seal products (special symbols K3 and S5) is smaller than that of ordinary products. The high-speed unit and the blower unit operate under high-speed rotation, and at the same time use non-contact oil seals to suppress heat, vibration and noise during operation.