Friction torque and heating of the outer spherical bearing

The friction torque of ball bearings for seated rolling bearings is a combination of rolling friction of rolling elements (balls) and raceway rings (outer ring, inner ring), sliding friction of rolling elements and cages, stirring resistance of lubricants, and friction of oil seals. Resistance. The friction torque is affected by the bearing type and size, bearing load, speed and lubrication conditions. In order to improve the sealing performance of the bearing, the seated rolling bearing especially adopts an oil seal with good dustproof performance, so the friction resistance of the oil seal occupies a large proportion of the friction torque of the bearing. The friction torque of the ball bearing for rolling bearing with seat can be calculated by the following formula. In the above formula, M: friction torque of the bearing, mN·m Mp: friction torque according to load changes, mN·m Mk: friction torque according to speed changes, mN·m μ: friction coefficient (0.001 5～0.002) P : Bearing load, N d: Nominal inner diameter of bearing, mm. However, it is difficult to calculate the values u200bu200bof the stirring resistance of the lubricant and the frictional resistance of the oil seal that change according to the rotation speed. The measurement results of the friction torque of a representative rolling bearing with seat are shown in Figure 13.1. An example of the measurement result of the friction torque of a seated rolling bearing. Bearing temperature rise: The temperature rise of ball bearings for rolling bearings 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 in proportion to the increase in the friction torque and the increase in the speed (the friction torque increases in proportion to the increase in the bearing load). The temperature rise of a ball bearing 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 the bearing housing to the outside. Therefore, the temperature rise of the ball bearing for rolling bearing with a seat is affected by the condition of the surrounding (the quality of the heat radiation environment) where the bearing with the seat is installed. The temperature of the seated rolling bearing rises slowly after the start of the operation, and if there is no abnormality, it reaches the highest after 1 to 2 hours, and then the temperature drops slightly and becomes a stable state (refer to Figure 13.2). The temperature of the bearing is almost a constant value if the operating conditions do not change, so the condition of the bearing can be estimated by measuring the temperature. Example of temperature measurement results of UCP208J with vertical seat bearing during operation. The temperature rise and friction torque of a seated rolling bearing during operation are the same, and it is different due to the different types of oil seals used in the bearing. The temperature rise of the triple seal product (accessory symbol L3) is larger than that of the ordinary product, and the temperature rise of the non-contact seal product (special symbol K3, S5) is smaller than that of the ordinary product. High-speed components and blower components operate at high speeds, and at the same time, non-contact oil seals are used to suppress heat generation, vibration, and noise during operation.