High-performance greases in heavily loaded rolling bearings
Plant that operates in quarries often has to contend with difficult conditions, and yet the expectations of reliability and efficiency for this equipment have never been higher.
Frequently those high expectations are demanded without much detailed consideration of the requirements of the machines and their individual components. For example, is it appropriate to expect high operational performance and longevity from equipment that is lubricated using products purchased on the basis of lowest cost per kg, and not the capability to provide long-term wear protection and reduced maintenance requirements?
Slow speed operation with heavy and shock loads is the norm for a large quantity of quarrying plant, and the use of ‘commodity’ lubricants may leave much scope for improvement.
If we consider one aspect of rolling bearing operation – load - the applications C/P ratio allows conclusions to be made regarding the requirements of the grease. The C/P ratio is the ratio between the bearing’s basic dynamic load rating, C (in N), and its actual equivalent dynamic load P (in N). When C/P ratios are <10, it is critical to the achievement of satisfactory bearing life that greases with suitable extreme pressure characteristics are used. The lower the C/P ratio, the more difficult becomes satisfactory lubrication.
One method of assessing suitability of greases under these demanding conditions is the use of test rig simulation. The FAG FE8 rolling bearing lubricant tester is such a test rig that allows testing of lubricants in angular contact, spherical, cylindrical roller, and taper roller bearings, under specified loads, temperature, and duration.
After test completion, the bearings are disassembled, inspected and weighed to evaluate wear that has occurred during the test. If the wear on the rolling rlements is ≤35mg then the lubricant can be categorized as a heavy-duty grease under FAG category LG12 requirements.
Klüberlub BE 41-1501 is one of a number of speciality greases from Klüber Lubrication that is designed for use in arduous operating conditions, with Klüberlub BE 41-1501 being particularly suitable for use on slow-speed, heavily loaded bearings. The FAG FE8 tests completed with Klüberlub BE 41-1501 show wear rates of only 18mg on taper roller bearings and 2mg on angular contact bearings.
An excerpt from the summary of the FAG FE8 test result states: ‘From the test results it can be concluded that Klüberlub BE 41-1501 meets the requirements for FAG grease category LG12. This means that it is suitable for application in low-speed rolling bearings subject to very high loads and shocks (in case of point and linear contacts) used, for example, in roller presses and bowl mill crushers.’
With a typical analysis of costs showing lubricant spend as only 1% of overall expenditure, it makes good commercial sense to consider the use of materials that give improved wear protection, and can positively influence factors such as downtime, maintenance, equipment reliability and production.
Klüber Lubrication Great Britain Ltd, Northowram, Hough Mills, Halifax HX3 7BN; tel: (01422) 205115.
Frequently those high expectations are demanded without much detailed consideration of the requirements of the machines and their individual components. For example, is it appropriate to expect high operational performance and longevity from equipment that is lubricated using products purchased on the basis of lowest cost per kg, and not the capability to provide long-term wear protection and reduced maintenance requirements?
Slow speed operation with heavy and shock loads is the norm for a large quantity of quarrying plant, and the use of ‘commodity’ lubricants may leave much scope for improvement.
If we consider one aspect of rolling bearing operation – load - the applications C/P ratio allows conclusions to be made regarding the requirements of the grease. The C/P ratio is the ratio between the bearing’s basic dynamic load rating, C (in N), and its actual equivalent dynamic load P (in N). When C/P ratios are <10, it is critical to the achievement of satisfactory bearing life that greases with suitable extreme pressure characteristics are used. The lower the C/P ratio, the more difficult becomes satisfactory lubrication.
One method of assessing suitability of greases under these demanding conditions is the use of test rig simulation. The FAG FE8 rolling bearing lubricant tester is such a test rig that allows testing of lubricants in angular contact, spherical, cylindrical roller, and taper roller bearings, under specified loads, temperature, and duration.
After test completion, the bearings are disassembled, inspected and weighed to evaluate wear that has occurred during the test. If the wear on the rolling rlements is ≤35mg then the lubricant can be categorized as a heavy-duty grease under FAG category LG12 requirements.
Klüberlub BE 41-1501 is one of a number of speciality greases from Klüber Lubrication that is designed for use in arduous operating conditions, with Klüberlub BE 41-1501 being particularly suitable for use on slow-speed, heavily loaded bearings. The FAG FE8 tests completed with Klüberlub BE 41-1501 show wear rates of only 18mg on taper roller bearings and 2mg on angular contact bearings.
An excerpt from the summary of the FAG FE8 test result states: ‘From the test results it can be concluded that Klüberlub BE 41-1501 meets the requirements for FAG grease category LG12. This means that it is suitable for application in low-speed rolling bearings subject to very high loads and shocks (in case of point and linear contacts) used, for example, in roller presses and bowl mill crushers.’
With a typical analysis of costs showing lubricant spend as only 1% of overall expenditure, it makes good commercial sense to consider the use of materials that give improved wear protection, and can positively influence factors such as downtime, maintenance, equipment reliability and production.
Klüber Lubrication Great Britain Ltd, Northowram, Hough Mills, Halifax HX3 7BN; tel: (01422) 205115.
