Definition: Refers to the degree to which grease hinders the rotation of low-speed ball bearings (open type 204 bearings) under low-temperature conditions.
① Low-temperature torque indicates the low-temperature performance of grease. Using a torque of 9.81 N·cm (1000 g·cm), the lowest temperature at which the bearing completes one rotation within one minute is measured as the grease’s minimum operating temperature.
② For motors lubricated with grease, in addition to overcoming the weight driven by the shaft itself, the strength limit of the grease in the bearing must also be overcome. This is particularly critical in environments with significant temperature variations and at low temperatures, where the increased strength limit of the grease can cause difficulties in rotation, oscillation, and sliding.
③ Therefore, the low-temperature torque of grease is not only related to the low-temperature viscosity of the base oil but also to the strength limit of the grease.
Ø Test Standard: SH/T 0338 “Test Method for Low Temperature Torque of Ball Bearing Grease”, Equivalent Method: ASTM-D1478