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ISO 26422:2014 pdf free

ISO 26422:2014 pdf free.Petroleum and related products – Determination of shear stability of lubricating oils containing polymers – Method using a tapered roller bearing
ISO 26422 specifies a method of determining the shear stability of polymer-containing lubricating oils by the four-ball machine as specified in ISO 20623, but using a tapered roller bearing.The test results allow prediction of the in-service permanent viscosity loss.
NOTE Other International Standards exist which evaluate viscosity loss of polymer-containing oils. The method specified within this International Standard subjects fluids to a higher shear rate than, for example, the diesel injector nozzle shear test described within ISO 20844.[3] It is particularly appropriate for lubricants being used in high shear applications, such as components with gears and roller bearings. In such applications, the shear rate in the ISO 20844 test method can be too low to generate a realistic permanent loss in viscosity of the fluid.
Using the splash lubrication method, a volume of 40 ml of the lubricating fluid is tested at a constant temperature of 60 °C in a tapered roller bearing driven in the four-ball machine. The test is performed at constant speed and the load applied during a given running time is 5 000 N. The kinematic viscosity of the lubricating fluid is determined at a temperature of 100°C before and after the test. The percentage viscosity loss, Rv, is calculated from these two viscosity measurements.
NOTE Some classification systems specify that the kinematic viscosity before and after shear is determined at temperatures other than 100 °C, e.g. at 40 °C.
Tapered roller bearing, type SKF 32008 X/Q which incorporates optimised contact geometry and surface finish. The single row tapered roller bearing consists of an inner ring with cage and roller assembly and an outer ring.
It is advisable that the inner and outer rings be considered to be a matched pair when obtained from the supplier and these components should not be interchanged with those of other sets of bearings.Precision has been established using the 32008 X/Q test bearing manufactured by SKF. It is strongly recommended that only bearings of this specification manufactured by SKF are used. The use of ISO 355 dimension series 3CD bearings of alternative specification and manufacturer requires validation by inter-laboratory exercises to establish technical suitability, test precision, and service life.ISO 26422 pdf free.

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