Thread Content
Part 1 of the Selection Guide for Installing Bearings and Heaters with Bearing Heaters. Installing Bearings with Bearing Heaters 1. Why should we use bearing heaters? Traditional heating methods such as oil bath, electric furnace heating, flame heating, etc. usually have the following problems.: a. It is time-consuming and labor-intensive, and the work intensity is high. b. It destroys the initial lubrication state of the bearing itself, which is easy to cause accidents. c. The heating temperature is uncontrollable, usually causing bearing annealing due to excessive temperature. d. Uneven heating leads to bearing deformation and damage. During the heating process, the temperature rises due to the metal part of the heated workpiece. The heater itself and the non-metallic parts of the heated workpiece (seals, lubricants, etc.) do not generate heat, so a bearing heater can be used to heat sealed bearings and pre-lubricated bearings. All closed metal workpieces can be heated with bearing heaters, such as bearings, gears, pulleys, couplings, back wheels, dust covers, pistons, etc. In short, as long as they are metal objects that can be penetrated by the heating rod, they can be heated with bearing heaters. Imported bearing heaters are equipped with automatic demagnetization function. The residual magnetism of the heated workpiece is < 2A/cm, which fully meets the general installation requirements. 3. The second generation bearing heater is based on the first generation bearing heater. The second generation bearing heater has the following innovations:: a20-80% power adjustment mode design can better control the heating time when heating small workpieces, avoid bearing damage due to excessive temperature rise, make the heating process safer, and save energy consumption (different bearing suppliers also have different requirements for bearing heating time) bExternal induction coil design, heating is more time-saving and energy-saving (the bearing heater can regard the heated workpiece as a coil with a small number of turns during operation. The smaller the distance between the two coils, the smaller the loss of the induced magnetic field) c Hard aluminum alloy body, lighter weight but stronger load-bearing d Built-in heating rod storage position, reducing the risk of damage and loss of the heating rod (many workers will throw away the heating rod as garbage) e Cooling fan design, supports long-term continuous work, especially suitable for continuous heating of the second part of the production line, the main basis for the selection of bearing heaters: 1. The weight of the bearing should usually not exceed the maximum weight of the workpiece that can be heated by the bearing heater, otherwise the machine will be crushed due to the overweight of the workpiece. Second, the outer diameter of the bearing should usually not exceed the maximum outer diameter of the heated workpiece, but strictly speaking, as long as the value of (Dd)/2 is not greater than W in the operating space range, that is, the bearing can be placed into the heater. Generally speaking, the height of the bearing can be ignored, unless it is an ultra-high bearing such as a multi-row bearing. (D=bearing outer diameter, d=bearing inner diameter, W=maximum width of heater operating space, see simatec Chinese sample P5 for details) 3. Bearing inner diameter, as long as the bearing can be penetrated by the heating rod, it can be heated by the heater, as long as the inner diameter of the bearing is greater than the diagonal distance of the thinnest heating rod cross-section. (If the bearing is too small, it is recommended to choose a cold installation tool or a bearing heating plate) 4. Extend the heating rod. Extending the heating rod means placing two heating rods of a certain length on the two vertical heating rods of the bearing to increase the heating range of the bearing heater. Therefore, the extended heating rods are used in pairs. 5. Voltage depends on the site conditions. Generally, bearing heaters can be changed to the specified voltage according to site requirements. 6. Heating temperature range: standard: 0-250℃, non-standard: 400℃ The temperature at which the bearing is heated mainly depends on the interference between the bearing and the shaft. Depending on the bearing supplier, the temperature at which the bearing is heated is also slightly different. Taking SKF as an example, most SKF bearings can meet its installation requirements as long as the indoor temperature is 80℃ higher than the indoor temperature. Usually, it is strictly prohibited to heat the bearings beyond 120°C, otherwise it will cause damage to the metallographic structure of the bearings, resulting in bearing damage. 8. Rotating heating rod or sliding heating rod. Rotating heating rod and sliding heating rod are designed to facilitate the removal of bearings from the heater. Generally, there is no need for such configuration if the weight of the bearing is not very large. For more information, please visit the Swiss Semir Chinese website: www.simatec.cn