1 Joint bearing knowledge Radial dynamic load rating: joint bearing of the working surface of the dynamic stress reaches the maximum allowable stress of radial load.
2 axial dynamic load rating: joint bearing of the working surface of the dynamic stress of the axial load reaches the maximum allowable stress.
3 life: joint bearing friction coefficient reaches the limit value in excess of the prescribed or joint bearing wear limit value when the total number of joint Low Price SKF Bearings work swing.
4 radial equivalent dynamic load: a constant radial load, under the effect of the load, the joint bearing working surface contact stress and the actual load. Joint bearing knowledge To the heart joint bearings, angular contact bearing joints, rod end joint bearing, bear radial load and axial load at the same time calculation of joint bearing service life. In general, for the radial, angular contact bearing joints under axial load is recommended not to exceed 30% of the radial load, rod end joint bearing under axial load is recommended not to exceed 20% of the radial load
Five axial equivalent dynamic load: a constant axial load, under the effect of the load, the joint bearing working surface contact stress and the actual load. For the thrust bearing bear radial load and axial load at the same time to calculate joint bearing service life. Joint bearing knowledge In general, for thrust bearing joints under radial load shall not exceed 50% of the axial load is recommended .
Six angular beta: swing ring on a swing diameter to the Angle between two limit position.
7 set time: swing joint bearing ring on a certain point the swing Angle of 2 beta for a set time.
Second, the selection of joint bearing .
When choosing joint bearing, joint bearing load size, direction should be considered, joint bearings and transmission ways, working condition and lubrication, positioning (radial, axial), the service life of requirement and installation and removal. Joint bearing knowledge Three, joint bearing fit .
The basic principles of joint bearing with choice.
4.1 according to the bearing types, dimensions, tolerances, clearance of bearing working conditions, the size of the effect on the bearing load, direction and nature of the material of shaft and the shell hole, convenient operation and etc for the choice of bearings and shaft and the shell hole.
4.2 the motion of the bearing ring generally USES the interference fit, the bearing work under load, the ring in the shaft and the shell hole with surface does not produce wear and relative rotation phenomenon. Joint bearing knowledge
4.3 to prevent sliding between inner ring and the shaft or crawling, inner ring and shaft should be preferred by interference fit, if convenient operation for or by using floating bearing, and must choose clearance fit, the journal must be hardened surface.
4.4 choose the interference fit, should be considered surplus quantity to the influence of radial clearance. For must use is greater than the occasion of surplus quantity, should choose the original clearance is greater than the basic group of bearing clearance value.
4.5 shaft and the shell hole tolerance zone . Joint bearing knowledge
4.5.1 axis of the tolerance zone according to the provisions of the table 1.
Four, joint bearing life calculation .
Theoretically calculate the service life of joint bearing, are assuming joint bearing installed correctly, normal load, temperature work, joint bearing lubrication is good, no alien invasion of joint bearing.
The service life of joint bearing and the bearing load, sliding speed, the friction pair material, equivalent dynamic load coefficient, load characteristics. Joint bearing knowledge Pulsating load (constant load and alternating load) coefficient and temperature coefficient of coefficient, sliding velocity life, load life factor and the quality of bearing and lubrication life factor, heavy lubricating life factor, lubrication Angle is related to life factor.
Seven, dry film (also called anti-friction coating, in film)
MoS2 lubricating dry film is "MoS2" + "adhesive" + "various quality improver and solvent composition," bearing surface spraying in the joints, and curing under a certain temperature, forming a layer of adhesive on the surface of the bearing, thin layer of lubrication, is advantageous to the running-in, film thickness 5 ~ 15 microns, do not move, the first time in sports film transferred to cooperate with the surface of some, promoted the transition period, until the lubricating oil film, to ensure the stability of the low coefficient of friction, avoid the peristalsis, surface pressure helps to lubrication film transfer process, therefore, joint bearings can bear full load after assembly. Joint bearing knowledge
Compared with the conventional lubricating oil, grease, surface modification layer has the following advantages:
Strong to prevent running in 1, prevent joint bearings spherical metal direct contact;
2 and joint bearing between the spherical surface modification layer has a certain binding force, so as to effectively guarantee the joint bearing lubrication in the use process;
3 and add oil N32 by mechanical blending oil or other, can greatly extend the life of knuckle bearing;
4 surface modification layer is suitable for in addition to water, acid and alkali substance environment, especially suitable for lubricating the mechanical mechanism of not in time. Joint bearing knowledge.