1. Sliding NTN bearings can also be lubricated with grease. The following points should be considered when selecting grease:
(1) When the bearing load of NTN shaft is large and the speed is low, the grease with small cone Sliding Ntn penetration should be selected, otherwise, the grease with large cone penetration should be selected.
High speed NTN bearings shall be lubricated with grease with Sliding Ntn smaller cone penetration and good mechanical stability. In particular, the viscosity of the base oil of the grease should be lower.
(2) The dropping point of the selected grease is generally 20-30 ℃ higher than the working Sliding Ntn temperature. Under the condition of continuous operation at high temperature, pay attention not to exceed the allowable temperature range of the grease.
(3) When the sliding NTN bearing works in water drenching or humid environment, calcium base, Sliding Ntn aluminum base or lithium base grease with good water resistance shall be selected.
(4) Select lubricating grease with good adhesion.
2. Selection of lubricating grease for sliding NTN bearing:
Load < 1MPa, journal circumferential speed less than Sliding Ntn 1m / s, high working temperature 75 ℃, select No. 3 calcium base grease;
The load is 1-6.5mpa, the circumferential speed of the journal is 0.5-5m/s, the high working temperature is 55 ℃, and No. 2 calcium base grease is selected;
Load > 6.5MPa, journal circumferential speed less than 0.5m/s, high working temperature 75 ℃, select No. 3 calcium base grease;
Load < 6.5MPa, journal circumferential speed 0.5-5m / s, high working temperature 120 ℃, select No. 2 lithium grease;
Load > 6.5MPa, journal circumferential speed less than 0.5m/s, high working temperature 110 ℃, select No. 2 calcium sodium base grease;
The load is 1-6.5mpa, the circumferential speed of the journal is less than 1m / s, the high working temperature is 50-100 ℃, and No. 2 lithium grease is selected;
Load > 5MPa, journal circumferential speed 0.5m/s, high working temperature 60 ℃, select No. 2 calender grease;
4. Mixed grease
Never mix incompatible oils and fats. If two incompatible oils and fats are mixed, their consistency will soften, and the IKO bearing may be damaged due to the easy loss of grease.
If you don’t know what kind of grease IKO bearing used originally, you must completely remove the old grease inside and outside IKO bearing before adding new grease.
5. Classification of oils and fats
It is mainly distinguished according to the temperature and working conditions: the grease can be classified according to their allowable working temperature. The consistency and lubrication ability of the grease are affected by the working temperature.
The IKO bearing operating at a certain temperature must choose the grease with correct consistency and good lubrication effect at the same temperature. Grease is made in different working temperature ranges, which can be roughly divided into low temperature, medium temperature and high temperature grease.
Pada saat yang sama, there is a kind of grease called extrusion resistance or extrusion resistance, and molybdenum disulfide is added. Pada saat yang sama, additives are added to strengthen the strength of lubricating oil film.
6. Important factors for selecting oil
If the grease is selected incorrectly, all measures to prevent IKO bearing are also futile. It is very important to select a grease whose base oil viscosity can provide sufficient lubrication effect at the working temperature. The viscosity is mainly affected by the temperature.
It decreases with the increase of temperature and increases when the temperature decreases. Karena itu, the base oil viscosity at operating temperature must be known. Machinery manufacturers usually specify the use of a certain grease, but most standard greases have a wide range of applications.
The following are several important factors for selecting grease: type of machinery; Type and size of IKO bearing; Operating temperature; Workload; Speed range; Working conditions, such as vibration and the direction of the spindle is horizontal or vertical; Cooling condition; Sealing effect; Peripheral environment.