The main compounds bearing work, can withstand bending and torque, to absorb some of the impact load. Axle overall carbon alloy hardened steel and quenched after hardening, induction heating 4 - 6mm hardened layer depth, hardness 50 ~ 55HRC. NTN Bearing production found, often self-aligning roller bearings burn out phenomenon, has seriously affected the production of NTN bearings and parts induction hardening quality. The test showed that and bearing burning area is located in the coil 225. Around the site, and expansion characteristics of the regularity of the two sides of the fault.

Axle sensor heating, in addition to the workpiece is heated, the heat generated by the sensors of the main heat losses in three ways.

(1) heat to the surrounding radiation. Guidance magnet, induction loop on the insulating paint and glass fiber cloth. This form of heat loss, heat evenly, sensor burnout.

(2) the heat of the cooling water. Germany Spherical Roller Bearing this part of the thermal cooling sensor so that the safe operation of the induction heating. The study found that the 0-180 degrees, the low temperature intake, showed a good heat exchange with the cooling water, the water smoothly, without the temperature of the water; over 180. Because the length of the flow path, the water temperature rises, the temperature of the water increases, so that heat exchange change, since the sensor can easily result in the rise in temperature of a site, which is the combustion of the main induction coil.

(3) the thermal conductivity of plate member of the induction coil, the current density of the part of the plate, the large cross-section and the water temperature is low, the area, in the region of the coil of the heat transfer plate. 0-90 and 270-360 part away from the vicinity of the induction loop board, good thermal conductivity; away from the plate, poor thermal conductivity, 90-270 induction loop, so that the greater induction loop temperature in the region is prone to in this is part of a phenomenon burnt coil. Spherical roller bearing induction loop heat different parts. 225 degrees near the area of ​​thermal sensing circuit and savings, so the difference between the area prone to induction loop combustion phenomenon.