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Accounting method for the service life of plastic mechanical rolling bearings
Source: Bearing network time: 2013-12-23
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The significance of this theory is not only that it provides a more robust guess of the modern bearing life than the ISO life equation; it also shows that the fatigue life of all rolling bearings has considerable development potential; The way to develop this potential; thus having a profound impact on the development, quality management and application skills of bearing products.
However, the infinite bearing can only be "completed" under the conditions of the laboratory; and such conditions are related to the bearing used in the field under certain working conditions; it is difficult and too expensive.
The bearing is used on site; its working load is often greater than its corresponding fatigue and extreme load; after the operation reaches a certain deadline; or late or early, it will always call the exhaustion limit because of its own data; the attack is exhausted and cannot be used continuously. The bearing load of these bearings is lower than their corresponding permanent limit load; the wear failure will also occur due to the difficult bearing pollution problem. In general, the bearings in the field application are more or less incapable of having the above-mentioned laboratory. Those conditions; and any condition in between is slightly lacking; will shorten the life of the bearing; this will break the bearing life of the bearing.
Generally speaking, the life of a rolling bearing refers to the service condition of the rolling bearing under practical conditions (including working conditions, environmental conditions, protection and protection conditions, etc.); the duration of service that can consistently meet the operational functions and accuracy of the automatic demand .
II. Countable bearing life types There are various failure modes of rolling bearings; however, there are no available life calculation methods for the majority of the failure modes; as long as the fatigue life, wear life, smooth life and micro-life Can be quantitatively evaluated by accounting.
1. The fatigue life is smooth and the other conditions are normal; the rolling bearing often fails due to fatigue; the life expectancy of the fatigue can be sampled to obtain relevant data; according to the formula and accounting procedures with certain reliability Calculate it.
2, wear life number of the machine's main bearing to take a large diameter to ensure its high stiffness; the size of the bearing is correspondingly large; before it reaches the exhaustion limit; often due to wear and tear, the accuracy must not be used continuously; It is necessary for the bearing to use the wear life to limit its service life. In practice, most of the bearings used in the field fail due to excessive wear; so it is also necessary to consider the wear life problem.
3, the smooth life number is mainly about the double-sided sealed grease smooth bearing; a grease filling will not make up for fatliquoring in the future; at this moment, the bearing life depends on the service life of the grease.
4. Frequently abraded life winches, cantilevered miniature heavy machines and gearboxes, and clutches in the arrangement of automobiles; in the case of non-operational conditions, the fretting damage caused by the oscillating load is often carried out. The leading cause of bearing failure; for bearings in such arrangements; sometimes it is necessary to account for the fretting life.
Now we will analyze the four lifespan varieties and their accounting methods.
First, the fatigue life of the rolling bearing 1, the basic concept of the bearing fatigue life usually refers to the bearing fatigue life refers to the rolling bearing under certain skill conditions (layout, process conditions, cooperation, installation, clearance and smooth condition, etc.) The total number of revolutions of the number of relative rotations of the inner and outer rings (shafts, races) of the bearing when the actual operation of the main engine is used; the bearing rotation is more stable or It is known; the number of hours of fatigue can be indicated by the total number of hours of work corresponding to the total number of revolutions; in addition;
1. There are many factors affecting the bearing fatigue life; it cannot be fully estimated or eliminated by standard experimental conditions; this forms a large dispersion of bearing practice fatigue life; therefore, the expression parameter of bearing fatigue life is extra life. The number L10, in the ISO referral specification R281, clearly defines the meaning of L10 as follows:
"The same number of bearings in quantity; the extra lifespan L10 is measured by the number of revolutions (or hours in the same speed; 90% of the bearings can reach or exceed this before the onset of fatigue loss) Number of revolutions (or hours). So far; countries all over the world follow the above rules.
In some countries such as the United States; the concept of median life is also used. The median lifespan LM refers to the median lifespan of a group of identical bearings; that is, 50% of the bearings can reach or exceed the total before the fatigue falls off. The number of revolutions; or the number of hours of operation at a certain speed; the median life LM is not the arithmetic mean of the number of bearing life. Usually the median life LM is about 5 times the extra life.
2. The concept of extra life is only applicable to a number of bearings that are satisfied by the quantity; not for a single bearing.
For example, there are 40 sets of 6204 bearings whose extra life is 1000h according to their application strips without causing fatigue damage; the other 4 sets can show fatigue-destroying bearings in less than 1000h; the meaning of extra fatigue life is representative of these bearings. The life expectancy in the normal development of its data potential. Therefore, under most conditions; users should first calculate the fatigue life when selecting the bearing; then check according to the practice failure varieties; for example, the wear life check; The smaller of the accounting results is the bearing life count.
Second, the estimation method of bearing fatigue life,
The estimation method of bearing fatigue life has two methods of accounting and experiment.
According to the formula and the accounting rules, the bearing fatigue life is calculated as the fatigue life; the calculated total rotation value is the total rotation value when the inner ring or the shaft ring is changed (the outer ring or the seat is fixed at the moment).
According to the normative experimental method of China's rules (ZQ 12-94), the test procedure for rolling bearing fatigue life); the experimental machine that can meet the requirements of one method in terms of function; the sampling fatigue test of a batch of bearings The actual experimental life obtained from the experimental data processing; that is, the fatigue test life of the batch of bearings represented by the bearing under test.
The fatigue life test of the rolling bearing is the wear factor of the sleek rolling bearing with sufficient smoothness and maximum limit; the intensive fatigue life test method with enhanced load and speed to select the outstanding bearing fatigue factor.
The nuclear algorithm and the fatigue life test of bearing fatigue life are mutually reinforcing; the results obtained by the two have satisfactory correspondence.
In fact; for each specific application, it is necessary to extract a satisfactory number of bearings for life test; to verify whether the selected bearing is suitable; this is very economic, time and labor; The experimental method of the bearing life is only used in very necessary or important conditions; in the vast majority of conditions; the standard life calculation method is used to estimate the service life of the bearing; there is a degree of satisfaction.
III. Accounting for fatigue life The calculation method for the following bearing fatigue life is based on the national standard GB6391-96 "Rolling bearing - calculation of extra dynamic load and extra lifespan" and national standard ISO281/I-1997 "rolling bearing extra The dynamic load and extra life are on the top of the list: the accounting method is based on; in addition; the new bearing company's new bearing fatigue life theory and the fatigue life accounting method of Sweden SKF Bearing Company are also analyzed.
1. The basic accounting formula of the fatigue life number There are many ways to calculate the basic accounting formula of the fatigue life of the bearing; to meet the needs of different habits;
.1) Fundamental extra life equation (indicated by total number of revolutions)
1. Several related fundamental concepts; before analyzing the fundamental extra life equation; first analyze the fundamental concepts of several associations:
The fatigue life of a single bearing is the first time that a single ring (or washer) or rollover material is fatigued before expansion; a ferrule (or washer) is associated with another ferrule (or washer) transition. Number of revolutions.
Reliability of bearing life under the same conditions A group of bearings of the same condition operating under the same conditions; the percentage of life that can be expected to reach or exceed a certain standard; for a single bearing; its reliability is the bearing The concept of being able to reach or exceed a certain number of life.
The fundamental extra life of the bearing is a single bearing or a set of bearings with the same skill conditions under the same conditions; the life of the bearing reaches 90%.
3. The accounting formula of the fundamental extra life equation is expressed by the total number of revolutions. The calculation formula of the bearing extra life equation is:
L10=C/P
The fundamental extra fatigue life of the L10 bearing (106r);
C is a radial equivalent dynamic load (N) for radial bearings and an axial equivalent dynamic load (N) for thrust bearings.
P is a radial equivalent dynamic load (N) for radial bearings and an axial equivalent dynamic load (N) for thrust bearings.
ε life index; for ball bearings ε = 3; for rolling bearings ε = 10 / 3.
Equation 5-1 is the normative accounting formula for the extra extra life of rolling bearings in China's national norms and international norms.
The number of revolutions of the bearing fatigue tester; the ability to accurately record the total number of revolutions of the bearing fatigue test; to facilitate comparison with the accounting results.
4. Applicable scale of the fundamental extra life equation. The extra extra life equation 5-1 is applicable to the rolling bearing with the following skill conditions. The bearing dimensions are selected from the scale of the bearing scale in the corresponding national regulations. The bearings are made of high-quality hardened steel and the processing quality is excellent. The surface quality of the bearing rolling touch surface (including several shape accuracy and raw materials, etc.) conforms to the customary specifications. These bearings are necessary to be correct; smooth and full; no external impurities invade and not at the pole Work under conditions.
When these conditions are not met; the calculation results of Equation 5-1 will cause errors. In order to offset such errors, it is necessary to multiply the results calculated by Equation 5-1 by the corresponding correction coefficients.
5. The use of the fundamental extra life equation constrains the fundamental extra life equation 5-1 not applicable, for example, with filled deep groove ball bearings; or there is a considerable gap in the touch area between the tumbler and the ferrule raceway Other varieties of bearings; because this gap affects the bearing capacity of the touch zone.
Equation 5-1 is not applicable to the case where the rolling body directly works on the outer surface of the shaft or the seat hole; unless the corresponding shaft or seat hole is completely made according to the skill conditions of the bearing element of the rolling bearing.
When the bearing is used in practice, the load it receives is abnormally distributed (for example, because the axis is not centered; the outer casing or shaft has large deformation; the centrifugal force effect of the rolling body or other high-speed effects; and the unique large clearance of the radial bearing) Or the situation of preloading is formed; when the basic extra life is calculated according to Equation 5-1; the satisfactory result cannot be obtained.
Second, the estimation method of bearing fatigue life,
The estimation method of bearing fatigue life has two methods of accounting and experiment.
According to the formula and the accounting rules, the bearing fatigue life is calculated as the fatigue life; the calculated total rotation value is the total rotation value when the inner ring or the shaft ring is changed (the outer ring or the seat is fixed at the moment).
According to the normative experimental method of China's rules (ZQ 12-94), the test procedure for rolling bearing fatigue life); the experimental machine that can meet the requirements of one method in terms of function; the sampling fatigue test of a batch of bearings The actual experimental life obtained from the experimental data processing; that is, the fatigue test life of the batch of bearings represented by the bearing under test.
The fatigue life test of the rolling bearing is the wear factor of the sleek rolling bearing with sufficient smoothness and maximum limit; the intensive fatigue life test method with enhanced load and speed to select the outstanding bearing fatigue factor.
The nuclear algorithm and the fatigue life test of bearing fatigue life are mutually reinforcing; the results obtained by the two have satisfactory correspondence.
In fact; for each specific application, it is necessary to extract a satisfactory number of bearings for life test; to verify whether the selected bearing is suitable; this is very economic, time and labor; The experimental method of the bearing life is only used in very necessary or important conditions; in the vast majority of conditions; the standard life calculation method is used to estimate the service life of the bearing; there is a degree of satisfaction.
III. Accounting for fatigue life The calculation method for the following bearing fatigue life is based on the national standard GB6391-96 "Rolling bearing - calculation of extra dynamic load and extra lifespan" and national standard ISO281/I-1997 "rolling bearing extra The dynamic load and extra life are on the top of the list: the accounting method is based on; in addition; the new bearing company's new bearing fatigue life theory and the fatigue life accounting method of Sweden SKF Bearing Company are also analyzed.
1. The basic accounting formula of the fatigue life number There are many ways to calculate the basic accounting formula of the fatigue life of the bearing; to meet the needs of different habits;
.1) Fundamental extra life equation (indicated by total number of revolutions)
1. Several related fundamental concepts; before analyzing the fundamental extra life equation; first analyze the fundamental concepts of several associations:
The fatigue life of a single bearing is the first time that a single ring (or washer) or rollover material is fatigued before expansion; a ferrule (or washer) is associated with another ferrule (or washer) transition. Number of revolutions.
Reliability of bearing life under the same conditions A group of bearings of the same condition operating under the same conditions; the percentage of life that can be expected to reach or exceed a certain standard; for a single bearing; its reliability is the bearing The concept of being able to reach or exceed a certain number of life.
The fundamental extra life of the bearing is a single bearing or a set of bearings with the same skill conditions under the same conditions; the life of the bearing reaches 90%.
3. The accounting formula of the fundamental extra life equation is expressed by the total number of revolutions. The calculation formula of the bearing extra life equation is:
L10=C/P
The fundamental extra fatigue life of the L10 bearing (106r);
C is a radial equivalent dynamic load (N) for radial bearings and an axial equivalent dynamic load (N) for thrust bearings.
P is a radial equivalent dynamic load (N) for radial bearings and an axial equivalent dynamic load (N) for thrust bearings.
ε life index; for ball bearings ε = 3; for rolling bearings ε = 10 / 3.
Equation 5-1 is the normative accounting formula for the extra extra life of rolling bearings in China's national norms and international norms.
The number of revolutions of the bearing fatigue tester; the ability to accurately record the total number of revolutions of the bearing fatigue test; to facilitate comparison with the accounting results.
4. Applicable scale of the fundamental extra life equation. The extra extra life equation 5-1 is applicable to the rolling bearing with the following skill conditions. The bearing dimensions are selected from the scale of the bearing scale in the corresponding national regulations. The bearings are made of high-quality hardened steel and the processing quality is excellent. The surface quality of the bearing rolling touch surface (including several shape accuracy and raw materials, etc.) conforms to the customary specifications. These bearings are necessary to be correct; smooth and full; no external impurities invade and not at the pole Work under conditions.
When these conditions are not met; the calculation results of Equation 5-1 will cause errors. In order to offset such errors, it is necessary to multiply the results calculated by Equation 5-1 by the corresponding correction coefficients.
5. The use of the fundamental extra life equation constrains the fundamental extra life equation 5-1 not applicable, for example, with filled deep groove ball bearings; or there is a considerable gap in the touch area between the tumbler and the ferrule raceway Other varieties of bearings; because this gap affects the bearing capacity of the touch zone.
Equation 5-1 is not applicable to the case where the rolling body directly works on the outer surface of the shaft or the seat hole; unless the corresponding shaft or seat hole is completely made according to the skill conditions of the bearing element of the rolling bearing.
When the bearing is used in practice, the load it receives is abnormally distributed (for example, because the axis is not centered; the outer casing or shaft has large deformation; the centrifugal force effect of the rolling body or other high-speed effects; and the unique large clearance of the radial bearing) Or the situation of preloading is formed; when the basic extra life is calculated according to Equation 5-1; the satisfactory result cannot be obtained.
Second, the estimation method of bearing fatigue life,
The estimation method of bearing fatigue life has two methods of accounting and experiment.
According to the formula and the accounting rules, the bearing fatigue life is calculated as the fatigue life; the calculated total rotation value is the total rotation value when the inner ring or the shaft ring is changed (the outer ring or the seat is fixed at the moment).
According to the normative experimental method of China's rules (ZQ 12-94), the test procedure for rolling bearing fatigue life); the experimental machine that can meet the requirements of one method in terms of function; the sampling fatigue test of a batch of bearings The actual experimental life obtained from the experimental data processing; that is, the fatigue test life of the batch of bearings represented by the bearing under test.
The fatigue life test of the rolling bearing is the wear factor of the sleek rolling bearing with sufficient smoothness and maximum limit; the intensive fatigue life test method with enhanced load and speed to select the outstanding bearing fatigue factor.
The nuclear algorithm and the fatigue life test of bearing fatigue life are mutually reinforcing; the results obtained by the two have satisfactory correspondence.
In fact; for each specific application, it is necessary to extract a satisfactory number of bearings for life test; to verify whether the selected bearing is suitable; this is very economic, time and labor; The experimental method of the bearing life is only used in very necessary or important conditions; in the vast majority of conditions; the standard life calculation method is used to estimate the service life of the bearing;
III. Accounting for fatigue life The calculation method for the following bearing fatigue life is based on the national standard GB6391-96 "Rolling bearing - calculation of extra dynamic load and extra lifespan" and national standard ISO281/I-1997 "rolling bearing extra The dynamic load and extra life are on the top of the list: the accounting method is based on; in addition; the new bearing company's new bearing fatigue life theory and the fatigue life accounting method of Sweden SKF Bearing Company are also analyzed.
1. The basic accounting formula of the fatigue life number There are many ways to calculate the basic accounting formula of the fatigue life of the bearing; to meet the needs of different habits;
.1) Fundamental extra life equation (indicated by total number of revolutions)
1. Several related fundamental concepts; before analyzing the fundamental extra life equation; first analyze the fundamental concepts of several associations:
The fatigue life of a single bearing is the first time that a single ring (or washer) or rollover material is fatigued before expansion; a ferrule (or washer) is associated with another ferrule (or washer) transition. Number of revolutions.
Reliability of bearing life under the same conditions A group of bearings of the same condition operating under the same conditions; the percentage of life that can be expected to reach or exceed a certain standard; for a single bearing; its reliability is the bearing The concept of being able to reach or exceed a certain number of life.
The fundamental extra life of the bearing is a single bearing or a set of bearings with the same skill conditions under the same conditions; the life of the bearing reaches 90%.
3. The accounting formula of the fundamental extra life equation is expressed by the total number of revolutions. The calculation formula of the bearing extra life equation is:
L10=C/P
The fundamental extra fatigue life of the L10 bearing (106r);
C is a radial equivalent dynamic load (N) for radial bearings and an axial equivalent dynamic load (N) for thrust bearings.
P is a radial equivalent dynamic load (N) for radial bearings and an axial equivalent dynamic load (N) for thrust bearings.
ε life index; for ball bearings ε = 3; for rolling bearings ε = 10 / 3.
Equation 5-1 is the normative accounting formula for the extra extra life of rolling bearings in China's national norms and international norms.
The number of revolutions of the bearing fatigue tester; the ability to accurately record the total number of revolutions of the bearing fatigue test; to facilitate comparison with the accounting results.
4. Applicable scale of the fundamental extra life equation. The extra extra life equation 5-1 is applicable to the rolling bearing with the following skill conditions. The bearing dimensions are selected from the scale of the bearing scale in the corresponding national regulations. The bearings are made of high-quality hardened steel and the processing quality is excellent. The surface quality of the bearing rolling touch surface (including several shape accuracy and raw materials, etc.) conforms to the customary specifications. These bearings are necessary to be correct; smooth and full; no external impurities invade and not at the pole Work under conditions.
When these conditions are not met; the calculation results of Equation 5-1 will cause errors. In order to offset such errors, it is necessary to multiply the results calculated by Equation 5-1 by the corresponding correction coefficients.
5. The use of the fundamental extra life equation constrains the fundamental extra life equation 5-1 not applicable, for example, with filled deep groove ball bearings; or there is a considerable gap in the touch area between the tumbler and the ferrule raceway Other varieties of bearings; because this gap affects the bearing capacity of the touch zone.
Equation 5-1 is not applicable to the case where the rolling body directly works on the outer surface of the shaft or the seat hole; unless the corresponding shaft or seat hole is completely made according to the skill conditions of the bearing element of the rolling bearing.
When the bearing is used in practice, the load it receives is abnormally distributed (for example, because the axis is not centered; the outer casing or shaft has large deformation; the centrifugal force effect of the rolling body or other high-speed effects; and the unique large clearance of the radial bearing) Or the situation of preloading is formed; when the basic extra life is calculated according to Equation 5-1; the satisfactory result cannot be obtained.
Second, the estimation method of bearing fatigue life,
The estimation method of bearing fatigue life has two methods of accounting and experiment.
According to the formula and the accounting rules, the bearing fatigue life is calculated as the fatigue life; the calculated total rotation value is the total rotation value when the inner ring or the shaft ring is changed (the outer ring or the seat is fixed at the moment).
According to the normative experimental method of China's rules (ZQ 12-94), the test procedure for rolling bearing fatigue life); the experimental machine that can meet the requirements of one method in terms of function; the sampling fatigue test of a batch of bearings The actual experimental life obtained from the experimental data processing; that is, the fatigue test life of the batch of bearings represented by the bearing under test.
The fatigue life test of the rolling bearing is the wear factor of the sleek rolling bearing with sufficient smoothness and maximum limit; the intensive fatigue life test method with enhanced load and speed to select the outstanding bearing fatigue factor.
The nuclear algorithm and the fatigue life test of bearing fatigue life are mutually reinforcing; the results obtained by the two have satisfactory correspondence.
In fact; for each specific application, it is necessary to extract a satisfactory number of bearings for life test; to verify whether the selected bearing is suitable; this is very economic, time and labor; The experimental method of the bearing life is only used in very necessary or important conditions; in the vast majority of conditions; the standard life calculation method is used to estimate the service life of the bearing; there is a degree of satisfaction.
III. Accounting for fatigue life The calculation method for the following bearing fatigue life is based on the national standard GB6391-96 "Rolling bearing - calculation of extra dynamic load and extra lifespan" and national standard ISO281/I-1997 "rolling bearing extra The dynamic load and extra life are on the top of the list: the accounting method is based on; in addition; the new bearing company's new bearing fatigue life theory and the fatigue life accounting method of Sweden SKF Bearing Company are also analyzed.
1. The basic accounting formula of the fatigue life number There are many ways to calculate the basic accounting formula of the fatigue life of the bearing; to meet the needs of different habits;
.1) Fundamental extra life equation (indicated by total number of revolutions)
1. Several related fundamental concepts; before analyzing the fundamental extra life equation; first analyze the fundamental concepts of several associations:
The fatigue life of a single bearing is the first time that a single ring (or washer) or rollover material is fatigued before expansion; a ferrule (or washer) is associated with another ferrule (or washer) transition. Number of revolutions.
Reliability of bearing life under the same conditions A group of bearings of the same condition operating under the same conditions; the percentage of life that can be expected to reach or exceed a certain standard; for a single bearing; its reliability is the bearing The concept of being able to reach or exceed a certain number of life.
The fundamental extra life of the bearing is a single bearing or a set of bearings with the same skill conditions under the same conditions; the life of the bearing reaches 90%.
3. The accounting formula of the fundamental extra life equation is expressed by the total number of revolutions. The calculation formula of the bearing extra life equation is:
L10=C/P
The fundamental extra fatigue life of the L10 bearing (106r);
C is a radial equivalent dynamic load (N) for radial bearings and an axial equivalent dynamic load (N) for thrust bearings.
P is a radial equivalent dynamic load (N) for radial bearings and an axial equivalent dynamic load (N) for thrust bearings.
ε life index; for ball bearings ε = 3; for rolling bearings ε = 10 / 3.
Equation 5-1 is the normative accounting formula for the extra extra life of rolling bearings in China's national norms and international norms.
The number of revolutions of the bearing fatigue tester; the ability to accurately record the total number of revolutions of the bearing fatigue test; to facilitate comparison with the accounting results.
4. Applicable scale of the fundamental extra life equation. The extra extra life equation 5-1 is applicable to the rolling bearing with the following skill conditions. The bearing dimensions are selected from the scale of the bearing scale in the corresponding national regulations. The bearings are made of high-quality hardened steel and the processing quality is excellent. The surface quality of the bearing rolling touch surface (including several shape accuracy and raw materials, etc.) conforms to the customary specifications. These bearings are necessary to be correct; smooth and full; no external impurities invade and not at the pole Work under conditions.
When these conditions are not met; the calculation results of Equation 5-1 will cause errors. In order to offset such errors, it is necessary to multiply the results calculated by Equation 5-1 by the corresponding correction coefficients.
5. The use of the fundamental extra life equation constrains the fundamental extra life equation 5-1 not applicable, for example, with filled deep groove ball bearings; or there is a considerable gap in the touch area between the tumbler and the ferrule raceway Other varieties of bearings; because this gap affects the bearing capacity of the touch zone.
Equation 5-1 is not applicable to the case where the rolling body directly works on the outer surface of the shaft or the seat hole; unless the corresponding shaft or seat hole is completely made according to the skill conditions of the bearing element of the rolling bearing.
When the bearing is used in practice, the load it receives is abnormally distributed (for example, because the axis is not centered; the outer casing or shaft has large deformation; the centrifugal force effect of the rolling body or other high-speed effects; and the unique large clearance of the radial bearing) Or the situation of preloading is formed; when the basic extra life is calculated according to Equation 5-1; the satisfactory result cannot be obtained.
For all types of bearings; when its equivalent dynamic load Pr or Po is greater than its fundamental additional dynamic load Cr or Co; together with the deep groove ball bearing; when its equivalent dynamic load Pr is greater than its fundamental additional static load Co; The use of 1 is also constrained; at this moment; bearing users can ask the relevant bearing manufacturer how to calculate the fatigue life of the above bearings.
Equation 5-1 has not yet estimated the characteristics (components, inclusions, arrangement, hardness, etc.) of high-quality hardened steel or the influence of data elements and operating conditions on bearing fatigue life; on double-row radial bearings and two-way thrust Bearing; it is necessary to approximate the assumption that these bearings are ambiguous when using this formula.
2. The fundamental extra life equation indicated by the total hours of operation is in the condition that the rotational speed is stable; the formula for calculating the extra extra life is indicated by the total hours; it is convenient to determine the repair and replacement cycle of the bearing. Need to change 5-1 to get; that is, Ln extra fatigue life (h);
n Speed ​​(r/min).
2. The formula indicated by the number of kilometers traveled; the rolling bearing used in the hub of various vehicles; the number of kilometers used to indicate the life is convenient; such a formula is the additional fatigue life (KM) of LK in the formula,
DR wheel diameter (mm).
3, high-availability life-selling formula for an important use; demand bearing hopes the fatigue life is more than 90%, at this moment the high-reliability fatigue life calculation formula is Ln=a1L10
Where Ln increases the number of years of fatigue (h);
L10 extra fatigue life (106r/h);
A1 Durable life expectancy (106r/h);
A1 reliability correction coefficient.
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