The speed of the motor bearing is mainly limited by the temperature rise caused by the friction and heat inside the bearing model. When the speed exceeds a certain limit, the bearing will be unable to continue rotating due to burns, etc. The limiting speed of a bearing refers to the limit value of the speed at which the bearing can rotate continuously without generating frictional heat that may cause burns. Therefore, the limiting speed of the bearing depends on various factors such as the type, size and accuracy of the bearing, the lubrication method, the quality and quantity of lubricant, the material and type of the cage, and the load conditions.

The limiting speeds of various bearings using grease lubrication and oil lubrication (oil bath lubrication) are listed in each bearing size table. The values represent the standard designed bearings under general load conditions (C/P≥13, Fa/Fr≤0.25 or so ) is the limit value of the rotation speed when rotating at low speed. Correction of limit speed: load condition C/P <13 (that is, the equivalent dynamic load P exceeds about 8% of the basic dynamic load rating C), or when the axial load in the combined load exceeds 25% of the radial load, it must Use equation (1) to correct the limit speed. na=f1·f2·n…………(1) The corrected limit, rpm, the correction coefficient related to the load condition (Fig. 1), the correction coefficient related to the resultant load (Fig. 2), the limit speed under general load conditions, rpm (refer to the bearing size table) basic dynamic load rating, N{kgf} equivalent dynamic load, N{kgf} radial load, N{kgf} axial load, N{kgf} pole motor and high-speed rotation Precautions: Bearings in When rotating at high speed, especially when the speed is close to or exceeds 70% of the limit speed recorded in the dimension table, the following matters should be paid attention to: (1) Use high-precision bearings (2) Analyze the internal clearance of the bearing (consider the temperature rise inside the bearing) Clearance reduction) (3) Analyze the type of material of the cage (4) Analyze the lubrication method.