The working temperature of cylindrical roller bearings depends on various factors, including the heat output of all relevant heat sources, the heat flow rate between heat sources, and the heat dissipation capacity of the system. The heat source includes bearings, sealing rings, gears, clutches, and oil supply, among others. Heat dissipation depends on many factors, including the material and design of the shaft and bearing seat, the circulation of lubricating oil, and external environmental conditions. These factors will be introduced separately in subsequent chapters. Under normal working conditions, most of the torque and heat of the bearing model come from the elastic fluid dynamic loss at the contact area of the roller/bearing ring. Heating is a product of bearing torque and speed. Calculate the heat output using the following formula. Qgen=k4n M tapered bearings can use the following formula to calculate torque. M=k1G1 (n μ) 0.62 (Peq) 0.3, where k1=bearing torque constant=2.56 x 10-6 (M is in Newton meters) k4=0.105 (Qgen is in W, M is in Newton meters) non tapered bearings and the calculation method for torque is given in subsequent chapters.
Heat dissipation: How to determine the heat flow rate of bearings in special applications is a complex problem. Generally speaking, it can be considered that the factors affecting heat dissipation rate include: 1 Temperature gradient from bearing to bearing seat. This factor is influenced by the size of the bearing seat and external cooling devices (such as fans, water cooling devices, etc.). 2. Temperature gradient from bearing to shaft. All other heat sources, such as gears and other bearings, as well as adjacent components, can affect the temperature of the shaft. 3. The heat carried away by the circulating oil lubrication system. To some extent, factors 1 and 2 can vary depending on the application. The heat dissipation mode includes heat conduction in the system, convection on the inner and outer surfaces, and heat radiation between adjacent structures. In many applications, heat dissipation can be divided into two parts - the heat carried away by the circulating oil and the heat dissipated through the structure. The heat carried away by lubricating oil through the circulating oil system is easier to control. In splash lubrication systems, cooling coils can be used to control the temperature of the lubricating oil.
The heat carried away by the lubricating oil in the circulating oil lubrication system can be calculated using the following formula. Qoil=k6 Cp ρ F（ θ O- θ i) Where: k6=1.67 x 10-5 (Qoil in W)=1.67 x 10-2 (Qoil in BTU/min) If the circulating lubricating oil is mineral oil, the heat carried away can be calculated using the following formula: Qoil=k5 f（ θ O- θ i) The following coefficients apply to the heat generation and dissipation formulas listed on this page. Where: k5=28 (Qoil unit is W, f unit is L/minute, θ The unit is ° C).
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