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The measurement of internal friction during material flow is called Viscosity Parameters viscosity. In order to prevent indirect contact surface wear of moving parts, SKF Bearing Lubricating oil must have sufficient viscosity,
and the viscosity value decreases with the increase of temperature. Viscosity is an important physical and chemical performance index to evaluate the Viscosity Parameters quality of SKF Bearing Lubricating oil, which is of great significance for production, transportation and use.
Viscosity is the main technical index of SKF Bearing Lubricating oil, but the viscosity of SKF Bearing Lubricating oil shall not be higher than the degree affecting engine startup. The vast Viscosity Parameters majority of SKF Bearing Lubricating oil is classified according to its viscosity,
which is the main basis for oil selection of various equipment. The measurement methods of viscosity are divided into absolute viscosity and relative viscosity. Absolute viscosity is divided into dynamic viscosity and kinematic viscosity; Relative viscosity can be expressed by Engler viscosity, Saybolt Viscosity and Rayleigh viscosity.
Kinematic viscosity and dynamic viscosity are commonly used to Viscosity Parameters express the viscosity of oil products in China. The standard method for determining kinematic viscosity is GB / T 265, that is, the time for a certain volume of liquid to flow through a calibrated glass capillary under gravity.
The product of capillary constant and flow time of viscometer is the kinematic viscosity of liquid at this temperature. Foreign standard Viscosity Parameters methods for measuring the kinematic viscosity of oil products mainly include ASTM D445 in the United States, DIN 51562 in Germany and JIS k2283 in Japan.
In practical application, selecting lubricating oil with appropriate Viscosity Parameters viscosity can ensure the normal and reliable operation of mechanical equipment. Generally, for applications with low speed and high load, oil with high viscosity shall be selected to ensure sufficient oil film thickness and normal lubrication;
For high-speed and low load applications, oil with low viscosity shall be selected to ensure the normal starting and running torque of Viscosity Parameters mechanical equipment. The viscosity of engine lubricating oil is too large, the flow is slow, the upward flow is slow, and the oil pressure is high,
but the passing amount of lubricating oil is not large, which can not be supplemented to the friction surface in time, and the friction generated under continuous operation conditions is small. Due to the slow circulation speed of SKF Bearing Lubricating oil, it is difficult to clean the worn metal debris, carbon particles and dust from the friction surface in time.
During operation, due to the high viscosity of the lubricating oil, the friction between the friction surfaces of the parts increases. In order to Viscosity Parameters overcome the increased friction, it is necessary to consume more fuel and reduce the output power of the engine.
SKF Bearing Lubricating oil has high viscosity, the oil circulation speed is slow, and its cooling and heat dissipation effect is poor, which is easy to overheat the engine. The temperature rise is small, so that an oil film can be formed between moving parts at various operating temperatures.
The low temperature viscosity of some oil products, such as hydraulic transmission fluid and vehicle gear oil, is usually measured by Brinell viscometer method. GB / T 11145 in China, ASTM d2983 in the United States and DIN 51398 in Germany.
Therefore, do not use engine lubricating oil with too high viscosity, and the higher the viscosity, the better. Under the condition of ensuring lubrication, the lubricating oil with low viscosity shall be selected as far as possible according to the temperature range during use. However, for engines with serious wear and large clearance, lubricating oil with slightly higher viscosity can be appropriately selected.