NSK import bearing overheating failure causes and treatment methods

In the grinding, grinding wheel and workpiece contact zone, consume large amounts of energy, to produce a large number of grinding heat, local transient high temperature caused by grinding area. On the basis of the theory of linear motion heat source heat transfer formula derivation, calculation or by the method of infrared ray and measured experiment under the condition of instantaneous temperature thermocouple method, can be found in 0. 1 to 0. The grinding area within 001 ms instantaneous temperature up to 1000 ~ 1500 ℃. The instantaneous high temperature, which would have made certain depth on the surface of the work surface to produce high temperature oxidation, amorphous group, high temperature tempering, secondary hardening, and even burn cracking and other changes. ( 1) Surface under the action of transient high temperature oxide layer of the surface of the steel and the oxygen in the air, rises into extremely thin ( 20～30nm） The iron oxide thin layer. It is worth noting that the oxide layer thickness and surface grinding metamorphic layer is the total thickness test results in corresponding relation. This shows that the thickness of oxide layer, is directly related to the grinding process is an important symbol of grinding quality. ( 2) Amorphous layer organization grinding the instantaneous high temperature makes the workpiece surface reach a molten state, molten metal molecular flow is evenly coated to the work surface, and the matrix metal cooling at breakneck speed, formed a very thin layer of amorphous tissue layers. It has high hardness and toughness, but it is only about 10 nm, it is easy to be removed in the precision grinding processing. ( 3) High temperature tempering instantaneous high temperature can make the surface layer of grinding zone certain depth ( 10 ~ 100海里) Be heated to a temperature higher than the workpiece temperature tempering heat. In the absence of austenitizing temperature reached, with the improvement of heated temperature, the surface will produce one by one and heating temperature corresponding to the organization transformation, or high temperature tempering tempering hardness. The higher the heating temperature and hardness of the decline is more severe. NSK bearings of fever and its elimination method ( 1) Reason: low bearing precision method: choose regulation accuracy grade of NSK bearings. ( 2) Reason: different method of heart: main shaft bending or casing hole repair spindle or box. ( 3) Reason: the belt too tight method: make the elastic of the belt can be adjusted properly. ( 4) Reason: poor lubrication methods: choose brand lubricating materials and proper clean. ( 5) Reason: low assembly quality methods: improve the assembly quality. ( 6) Reason: bearing inner shell run laps method: replacement bearings and related worn parts. ( 7) Methods: the axial force is too big to clean, 0 is seal mouth ring clearance requirements. 2 to 0. 3 mm, correcting impeller balance hole diameter and check static equilibrium value. ( 8) Bearing damage method: change the NSK bearings.