Timken offers a large assortment of high-quality induction heaters designed for demanding industrial applications. They can heat and radially expand a wide variety of gears, rings, couplings, bearings and other components.
Timken induction heaters use the principle of induction, similar to a transformer. The heater and yokes remain cool; only the work piece is heated. During the induction heating cycle, a certain degree of magnetism occurs. All Timken heaters demagnetize automatically after each heating cycle.
The principle of bearing induction heater
Bearing induction heater is also called bearing electromagnetic heater, electromagnetic induction heater, induction heater, which is a kind of heating tool. The heating element is integrated with the platform, which is safe, reliable and easy to use. Mainly used to heat various types of metal parts such as bearings, gears, bushings, bushings, diameter rings, pulleys, shrink rings, connectors, etc. The electromagnetic bearing heater expands through heating to meet the needs of interference assembly .The power frequency induction technology of the bearing induction heater comes from an unexpected short-circuit accident of the transformer.In an unexpected accident, a huge amount of heat was released due to the instantaneous strong current. The principle is that electrical energy is converted into heat (the conversion efficiency is close to 100% after its own loss).Electromagnetic heating process: The bearing to be heated is placed on the movable induction heater yoke. The ring-shaped bearing ring is equivalent to a short-circuit coil with one turn. When the primary coil is supplied with power frequency or high frequency current, Due to the principle of electromagnetic induction, a large short-circuit current is induced in the bearing ring. At this time, the bearing is rapidly heated due to the electrothermal effect.
Electromagnetic heating bearing induction is the working principle of electromagnetic heaterThe induction heating of the bearing heater uses electromagnetic induction to generate a current magnetic field inside the heated workpiece itself to generate eddy currents to heat the workpiece, and rely on the energy of these eddy currents to achieve the purpose of heating. The basic composition of the bearing heater induction heating system includes: induction coil, AC power supply, workpiece and control part, using the principle of electromagnetic induction to convert electrical energy into heat. In the case of magnetic workpiece bearings, the eddy current generated in the bearing body causes the bearing surface to heat up at high speed and uniformity, and the temperature of the host does not change.
Electromagnetic heating Induction bearing heating technology is an advanced electric heating technology, which transmits energy through an electromagnetic field, so that the metal heated body heats itself to achieve the purpose of heating. The electromagnetic heating system generally includes two parts, an electromagnetic heating control board and a heating coil. The electromagnetic induction heating control board rectifies and filters the input power frequency alternating current of the power supply into a stream, and then inverts it into a high frequency alternating current of 1630kHz, and transmits it to the electromagnetic heating coil, and the heated body receives the electromagnetic heating coil. The high-frequency alternating electromagnetic field generates heat due to induced current. The temperature of the heated body can be controlled by installing a temperature controller on the heated body to control the electromagnetic heating control board.When the electromagnetic bearing heater and the induction disassembler work, the magnetic flux generated by the induction coil passes through the permeable magnet and the inner ring of the bearing. The change of magnetic flux induces eddy currents in the bearing inner ring, which heats the bearing inner ring.
However, applying care and good technique are usually better. Over 90% of rotating equipment has defects at startup that result in equipment failure. One of the reasons arises from making bearing installation a herculean task and not using proper technique. Excessive force applied during bearing installation can introduce defects that lead to premature equipment failure. Instead of beating the bearing on with a sledgehammer, gently heat it up on an induction heater, automatically demagnetize it, and then slip it on. If Hercules did the job, then the bearing and equipment are doomed to failure from the moment of startup. This results in increased maintenance costs, increased risks, and increased equipment downtime.
Installing equipment bearings should not be a herculean task. Instead, proper technique and best practice should be applied to correctly install bearings. Induction bearing heaters like SURETHERM can help eliminate induced bearing defects due to poor fitting and improper mounting techniques. Induction bearing heaters provide increased safety, increased efficiency and reduce the risk of bearing contamination and damage that can result from using brute strength, oil baths, blowtorches, or other improper methods to heat bearings for proper installation.
Most induction heaters only monitor the temperature of the inner race, neglecting the temperature of the outer race. The problem with this is that the two races will not expand at the same rate (see fig. 1). If the ID heats faster than the OD, it will create large stresses on the roller elements that get sandwiched between the inner and outer races. These stresses will create cracks, fractures, and/or pitting that may not be noticed, reducing the life span of the bearing. This also holds true for gears, as the membrane between the ID and OD will also be stressed and this may create cracks lead to fractures.
In order to satisfy QA/QC documentation requirements for the proper heating of a bearing, it would be necessary to have a graphing capability: a graph that will show both the temperature of the ID and OD over the time that it took the bearing to reach the desired preset temperature and the deviation between the two temperature curves in order to document that the two did not deviate from the maximum permissible difference entered between the ID and OD temperatures. In addition, the induction heater should also have the capability to export and print the graph.
Download our Basics of Induction Heating white paper to learn the basic principle behind induction heating, the diverse range of applications and advantages, and the different types of equipment you can use to reach your goals.
Previously a different portable induction heater had been used, but it took much too long, the heater itself got hot and it only had one temperature probe. The great advantage of the SURETHERM bearing heater is that the twin temperature probes let you precisely monitor the difference between the inner and outer race temperatures and keep that differential to a minimum in order to prevent stressing the bearing.
The experiment was to see whether on the second installation two bearings could be heated at the same time, placing one bearing around the post and the other on the crossbar, with one probe per bearing. Once again the induction heater worked flawlessly, heating both bearings within 2 minutes and both to the same temperature, 225 degrees Fahrenheit.
Proper application of heat with an induction heater eliminates all of the issues talked about so far. The induction heater guarantees that heat is evenly and accurately applied to the workpiece and that the workpiece is fully demagnetized before installation. If the technician has measured the bore and the shaft, cleaned everything properly for installation and used an induction heater to achieve the proper temperature, this job should go off without a hitch. Furthermore, there should be a report that showed how the hub was heated, over what span of time, and to what specified temperature. This eliminates a large amount of investigation (and possibly blame) in the event that a Failure Analysis investigation needs to be conducted.
Download our Basics of Induction Heating white paper and learn the basic principle behind induction heating, the diverse range of applications and advantages, and the different types of equipment you can use to reach your goals.
Overheating is a huge issue that is often observed while installing a bearing. There are multiple ways to heat a bearing before installation. You can use an oven, or a hot oil bath where you dip the bearing in boiling oil and heat it until you hope you get the right bearing temperature. You can also use a hot plate where you need to keep flipping the bearing over and over to try to get an even temperature on both sides. Another, and by far the best method is to use an induction heater. These come in different sizes, to handle from the smallest to the largest bearings with ease. They use eddy current heating and the system monitors the precise temperature of the bearing for you until it reaches the desired temperature. You need to take proper safety measures in every case.
In comparison, if an Induction Heater is used, make sure that you are using the correct induction heater based on the weight of the bearing, and also make sure that you are using the largest possible yoke or crossbar for the I.D. of the bearing being heated. Also make sure gloves are used to handle the bearing after the heating cycle is complete.
Place the bearing with either the horizontal yoke going through the bore or one of the vertical posts going through the bore. Set the desired temperature on the induction heater, make sure to place the temperature probe on the inner bore or ring of the bearing not on the outer diameter part.* Select the temperature to which you wish to heat the bearing (not to exceed 250 F) and press start to begin the heating cycle. Once the heating cycle is completed and the bearing has automatically been demagnetized** place the bearing on the shaft. 2ff7e9595c
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