Effect on the bearing load, under the force of known or calculable (
Such as driving force, work force, inertia force)
Can be calculated according to the principle of mechanics.
When calculating a single bearing load of the component, in order to simplify the calculation, the shaft is considered by the rigid and no moment is fulcrum bearing beam.
Bearings, bearing or the elastic deformation of mechanical structure, shaft deflection function bearing in moment, all is not considered in the calculation of simplified.
Application of the theory of more simplified and only need simple tools, such as a small calculator, can be calculated.
In fact, basic rated load and equivalent calculation of bearing load standard method, is based on similar assumptions.
Using advanced and complex calculation procedures, can need not the above assumptions, the bearing load is calculated according to elastic mechanics theory.
In the calculating program, bearings, shaft and bearing are considered as elastic part of the system.
Aspects including the shaft and the bearing force components inherent in weight, or the weight of the vehicle and other inertial force and so on, these are generally known number, or can be calculated.
But other external forces, such as the work force,
Ground stress and machine tool cutting force, etc. )
, the impact force and additional dynamic force (
Such as caused by unbalanced centrifugal force)
, usually must rely on the experience of similar machines or smoke bearing configuration can be determined.
Gear transmission for gear transmission, gear in theory produce force can be calculated according to the transmission power and the types of gears.
But there are also other dynamic force due to the gear, transmission end or output end.
In addition, the shape error of gear and rotating parts of imbalance can cause additional dynamic force.
But general gear at high accuracy standard, to reduce the noise of the runtime, so caused by such force is small, usually when calculating the bearing load can be neglected.
Application of gear transmission machine, only in the condition of known working conditions, can be determined according to its operation forms and patterns produced by the additional forces.
According to different working conditions, gear manufacturers often provides an impact on the 'work' coefficient of load and efficiency of the gear, using this coefficient, which can be used to consider the effect of additional forces of bearing rated life.
Belt drive when calculating the bearing load of belt transmission, the main belt is considered effective torque, it depends on the transmission of torque.
Belt manufacturers usually depending on the type of the belt don't ask, preloaded, belt tensioning force and additional dynamic force, to provide a system used to calculate the belt tension.
If cannot get related coefficient, can use the following reference: toothed belt -
—
1.
1 ~ 1.
3;
Triangle (
V belt)
—
—
1.
2 ~ 2.
5;
Flat belt -
—
1.
Five to four.
5;
When the distance between the axis is very short, in the heavy load, or under the action of impact load is large, or tension, should use a larger value.
The static load and dynamic load bearing of the bearing static load capacity, decided by the allows the amount of plastic deformation.
Plastic deformation of rolling bearings is inevitable.
If the limit allowed the plastic deformation of volume is small, the bearing static load capacity is small;
If allowed to plastic deformation is bigger, the roll on the pit will be increased bearing noise and vibration in the operation, running accuracy is reduced, affect the normal work of the bearing.
Rolling bearings, the load bearing the largest rolling element and raceway contact points, the total amount of plastic deformation is less than one over ten thousand of the diameter of the roller, has no much impact on the normal operation of bearing.
Put in this kind of plastic deformation under the condition of certain bearing static load capacity is called static load rating, usually expressed in C0.
Static load rating is determined in the assumed load conditions, the centripetal bearing, static load refers to the radial load rating of centripetal thrust bearing (
Angular contact ball bearing)
Is letting half a circle in the bearing raceway loading the radial component of the load, is refers to the center of thrust bearing axial load.
Bearing the basic rated static load and static load rating is refers to the bearing in a static or rotating, can withstand the biggest load.
Bearing dynamic load rating refers to the constant rolling bearing theory can bear radial load (
Constant axial load)
Basic rated under the action of the load, the life expectancy of 1 million RPM, bearing the basic dynamic load rating of bearing rolling fatigue resistance ability.
Centripetal bearing and thrust bearing don't referred to as the basic dynamic load rating of the basic dynamic load rating and axial radial basic dynamic load rating, expressed in Cr and Ca.
