RU2626800C1 - Method of ball bearingscompletion - Google Patents

Abstract

FIELD: machine engineering.

SUBSTANCE: method involves measuring the diameters of the raceways of the outer and inner rings at the contact angle under the action of the axial load. As an axial load, a ball load of P_k=A⋅z_k/z, while the diameter of the balls during picking is determined from the relation ds=(1,91÷1,92)⋅(rg_max+rg_min)/2, and the angle of contact in measuring the diameters of the raceways is defined as

, where P_k - the load at which the diameters of the raceways are measured, H; z_k' is the number of balls that measure the diameters of the raceways; z - number of balls in the assembled ball bearing; β₀ - nominal angle of contact in the bearing, provided during picking, rad.; Kr is the maximum value of the ratio of radial R and axial A of the bearing loads to the bearing during operation; ds is the diameter of the picking balls, mm; rg_max and rg_min - maximum and minimum permissible radii of the profile of the raceways, mm.

EFFECT: increasing the load bearing capacity of the rolling bearing while simplifying the picking process.

3 dwg, 1 tbl, 1 ex

Description

The invention relates to the field of engineering, in particular to methods for the selective assembly of rolling bearings, for example angular contact, axial-radial single and double row, and can be used in the bearing industry.

A known method of manning ball bearings by selecting the diameters of the raceways of the rings and rolling elements according to the size of the permissible radial clearance [RU No. 2127836]. The diameters of the raceways are measured automatically at the measuring positions of the component device, and before the start and during the acquisition process, a statistical analysis of the sizes of the bearing rings is carried out.

The disadvantage of this method is that it is intended only for radial rolling bearings.

There is also a method of completing thrust bearings by monitoring after assembling the contact angle in angular contact ball bearings according to the difference in rotational speeds of the bearing ring and cage [Chernevsky LV Technological support for precision assembly of precision products. M.: Engineering, 1984, pp. 122-132].

The disadvantage of this method is the high complexity, therefore, the application of this method is limited to special cases, for example, in the case of scientific research.

There is also a method of completing thrust-radial ball bearings by measuring radial, axial clearance and determining the contact angle in the bearing by the formula [SU No. 1320687].

The disadvantage of this method is that it can only be used to complete angular contact bearings with a small contact angle.

The closest in technical essence and the achieved effect to the claimed is a method of completing parts for the selective assembly of angular contact and angular contact ball bearings, including measuring the diameters of the raceways of the outer and inner rings at an angle of contact under the action of axial load [RU No. 2151582]. The balls are also subjected to measurement, followed by dividing them into size groups. Then, the relative position of the ends of the inner and outer rings under load is measured and, taking into account all the measurement parameters and the total acquisition error, the assembly is modeled, calculating the acquisition accuracy by finding the empirical law of the distribution of the output parameter according to the laws of distribution of the geometric parameters of the parts.

, где

- диаметр шариков [А.И. Спришевский. Подшипники качения. М., «Машиностроение», 1968. стр. 72]. На радиус профиля дорожки качения назначают допуск

. Поэтому установленное длительной практикой рациональное соотношение между радиусом профиля дорожек качения и диаметром шарика составляет

. При выходе за минимальное значение указанного соотношения повышается грузоподъемность подшипника, но резко возрастает трение, что не допустимо, так как резко возрастает износ дорожек и тел качения и возрастает температура на рабочей поверхности подшипника. При выходе за максимальное значение указанного соотношения резко снижается грузоподъемность подшипника. Но так как при комплектовании подшипников известным способом радиус профиля дорожек качения во внимание не принимают, то формирование комплектовочных групп с разным диаметром шариков приводит к различному соотношению в различных группах радиусов профиля дорожек и тел качения и в целом к нарушению указанного выше соотношения, что снижает эксплуатационные свойства подшипника. Так как грузоподъемность партии подшипников определяется его минимальным значением в партии, то в целом грузоподъемность подшипников при таком способе комплектования снижается.The disadvantage of the closest analogue is that it does not take into account the ratio of radial and axial working loads on the bearing, as a result of which the selected parameters for bearing assembly do not provide the required bearing capacity. In accordance with the current method for calculating the geometric parameters of ball bearings, the minimum radius of the raceway profile in standard bearings is

where

- the diameter of the balls [A.I. Sprishevsky. Rolling bearings. M., "Engineering", 1968. p. 72]. Tolerance is assigned to the radius of the raceway profile

. Therefore, the rational relationship established by long-term practice between the radius of the raceway profile and the diameter of the ball is

. When the minimum value of the specified ratio is exceeded, the bearing capacity increases, but friction increases sharply, which is not permissible, since the wear of tracks and rolling elements increases sharply and the temperature on the bearing working surface rises. When exceeding the maximum value of the specified ratio, the bearing capacity decreases sharply. But since when completing bearings in a known manner, the radius of the raceway profile is not taken into account, the formation of picking groups with different ball diameters leads to a different ratio in different groups of radii of the profile of tracks and rolling bodies and in general to the violation of the above ratio, which reduces operational bearing properties. Since the load capacity of a batch of bearings is determined by its minimum value in the batch, in general, the load capacity of bearings with this method of picking is reduced.

The objective of the present invention is to eliminate the noted drawback, namely, increasing the bearing capacity of a rolling bearing while simplifying the picking process.

, при этом диаметр шариков при комплектовании определяют из соотношения

, а угол контакта при измерении диаметров дорожек качения определяют как

, где

- нагрузка, при которой осуществляют измерение диаметров дорожек качения, Н;

- число шариков, которыми осуществляют измерение диаметров дорожек качения; z - число шариков в собранном шарикоподшипнике;

- номинальный угол контакта в подшипнике, обеспечиваемый в процессе комплектования, рад.;

- максимальное значение отношения радиальной R и осевой А рабочих нагрузок на подшипник в процессе эксплуатации;

- диаметр комплектовочных шариков, мм;

и

- максимально и минимально допустимые радиусы профиля дорожек качения, мм.The essence of the claimed invention lies in the fact that in the method of acquiring ball bearings, including measuring the diameters of the raceways of the outer and inner rings at a contact angle under the action of axial load, the load on the balls equal to

while the diameter of the balls during picking is determined from the ratio

, and the contact angle when measuring the diameters of the raceways is determined as

where

- the load at which the diameters of the raceways are measured, N;

- the number of balls that measure the diameters of the raceways; z is the number of balls in the assembled ball bearing;

- nominal contact angle in the bearing provided during the picking process, rad .;

- the maximum value of the ratio of radial R and axial A working loads on the bearing during operation;

- diameter of picking balls, mm;

and

- the maximum and minimum allowable radii of the raceway profile, mm.

The technical result consists in reducing the load on the balls by choosing the angle of completing the bearing, depending on the ratio of the radial and axial loads on the bearing and by keeping the ratio of the profile radius of the bodies and raceways unchanged in the bearing.

Since the picking angle of the bearing is selected depending on the ratio of the radial and axial working loads, this ensures a minimum load on the balls during operation of the bearing, which increases its load capacity. The measurement of the diameters of the raceways under the axial working load on the balls provides the required contact angle during the operation of the bearing, taking into account the real elastic deformation of the bodies and raceways, which also helps to increase the bearing capacity. The assembly of a bearing with a ball, the diameter of which is selected according to the indicated dependence, makes it possible to provide a rational ratio between the radii of the profile of the raceways and the diameter of the balls in various groups, which ensures normal operation of the bearing, prevents increased wear of the tracks and rolling elements and increased heat emission during operation of the bearing and in general increases bearing capacity of a batch of bearings.

The alleged invention is illustrated using FIG. 1-3, where in FIG. 1 shows a diagram with the designation of the picking parameters of an axial radial bearing, FIG. 2 - experimental dependence of the static load-bearing capacity of the bearing 1118-2902840 on the contact angle of the balls and raceways, FIG. 3 - experimental dependence of the torque of the radial thrust bearing 1118-2902840 on the contact angle of the balls and raceways.

In FIG. 1-3, the following notation is used:

1 - the upper ring of the thrust radial ball bearing;

2 - the lower ring of the thrust radial ball bearing;

3 - balls.

The acquisition method is as follows. First, calculate the diameter of the ball with which the bearing should be completed according to the formula

- диаметр комплектовочных шариков, мм;

- минимально допустимый радиус профиля дорожек качения, мм;

- максимально допустимый радиус профиля дорожек качения, мм.Where

- diameter of picking balls, mm;

- the minimum allowable radius of the raceway profile, mm;

- the maximum radius of the raceway profile, mm.

The existing selective acquisition of bearings involves the formation of dimensional groups of rings and balls. But changing the size of the ball during picking without taking into account the size of the radius of the profile of the raceways of the rings leads to a significant change in the bearing contact stresses, on the one hand, and a change in the friction moment in the bearing, which greatly depends on the ratio of the radii of the bodies and raceways. In those size groups where the minimum ball size is used, contact stresses increase and the friction moment decreases, and in those size groups where the maximum ball size is used, contact stresses decrease and the friction moment increases. In both cases, the bearing capacity will be low. Therefore, the proposed method manages with balls of the same size, and the required contact angle provides by dividing only the bearing rings into size groups. In this case, the same contact conditions between bodies and raceways with a rational ratio of their sizes are created in each size group.

Then determine the required nominal contact angle in the bearing, provided during the picking process, depending on the ratio of the radial and axial working loads on the bearing according to the formula

- номинальный комплектовочный угол контакта в подшипнике, обеспечиваемый в процессе комплектования, рад.;

- максимальное значение отношения радиальной R и осевой А рабочих нагрузок на подшипник в процессе эксплуатации.Where

- nominal picking contact angle in the bearing, provided during the picking process, rad .;

- the maximum value of the ratio of radial R and axial A working loads on the bearing during operation.

Typically, the picking contact angle is selected from a number of standard bearings, and then after the bearings are manufactured, the customer selects the bearing with the contact angle closest to the calculated value in terms of the equivalent load and the ratio between the radial and axial components. Since the pitch of the contact angles in standard bearings is large, the required contact angle does not coincide with the actual in the used bearing and therefore the load on the balls will be increased, which reduces the bearing capacity. Standard bearings are widely used not only in small-scale production, but also in mass production products - cars, airplanes, tractors, rockets, turbines, devices, tanks and other numerous equipment, where it is especially important and possible to use a rational contact angle. In these products, the maximum value of the ratio between the radial and axial loads is known in advance, and therefore, for these bearings, the contact angle should be formed when picking according to the proposed dependence, since this ensures a minimum load on the balls and a significant increase in bearing capacity, and therefore of that technique, which they are used.

In contrast to existing empirical dependencies, for example, described in [Korolev A.V., Reshetnikova O.P. Determination of the optimum contact angle in a thrust radial bearing. The collection of works “Young scientists - the basis of the future engineering and construction” - Kursk, May 29-30, 2014 - pp. 175-179], using mathematical modeling, a more accurate dependence of the load on the balls on the contact angle in the ball bearing was obtained. Based on these studies, the authors obtained the dependence (2) of the optimal contact angle in a ball bearing, depending on the ratio of the radial and axial load on the bearing.

и

каждого из колец под углом контакта. В качестве комплектовочного угла контакта используют значение

, рассчитанное по формуле (2), а нагрузку при измерении принимают равной рабочей осевой нагрузке, соответствующей максимальному значению

. Это позволяет осуществить комплектование подшипников с тем углом контакта, который возникнет в процессе работы подшипника, что обеспечит повышение его грузоподъемности.Next, the diameter of the raceways is measured.

and

each of the rings at an angle of contact. As a picking contact angle, use the value

calculated by the formula (2), and the load during the measurement is taken equal to the working axial load corresponding to the maximum value

. This allows you to complete the bearings with the contact angle that occurs during the operation of the bearing, which will increase its load capacity.

Then determine the nominal value of the difference in the diameters of the raceways of the upper and lower rings in each size group according to the formula

for angular contact bearings

for angular contact bearings

, мм;

и

- диаметры дорожек качения первого и второго колец в точке контакта, замеренные под рабочей нагрузкой.Where

mm;

and

- the diameters of the raceways of the first and second rings at the contact point, measured under the working load.

, где

- допуск на разницу диаметров дорожек качения колец, мм;

- максимальное допустимое значение разности диаметров в каждой размерной группе, мм;

- минимальное допустимое значение разности диаметров колец в каждой размерной группе, мм.Depending on the required accuracy of picking, they are specified by the tolerance for the difference in ring diameters in each group

where

- tolerance for the difference in the diameters of the raceways of the rings, mm;

- the maximum allowable value of the difference in diameters in each size group, mm;

- the minimum acceptable value of the difference in the diameters of the rings in each size group, mm

и

колец в каждой размерной группе.Determine the number of size groups and intervals of diameters

and

rings in each size group.

The proposed method of bearing assembly allows one to produce angular contact and axial radial ball bearings with a contact angle that ensures the minimum load on the balls in specific operating conditions, depending on the values acting on the bearing loads, and maintain a constant ratio between profile radii in each size group tracks and rolling bodies. This increases the bearing capacity and simplifies the picking process.

, радиальная нагрузка

. С учетом действия динамических нагрузок максимальная осевая нагрузка составляет

, максимальная радиальная нагрузка

, диаметр по дну дорожки качения верхнего кольца составляет

мм, диаметр дорожек качения нижних колец составляет

мм, радиусы желобов колец подшипника

;

. Число шариков в шарикоподшипнике равно

.Example. In accordance with the claimed method, the completion of the radial bearing 1118-2902840, installed in the upper support of the front pillar of VAZ automobiles of the Kalina, Priora, and Grant brands, was carried out. Bearing conditions: nominal axial load

radial load

. Given the action of dynamic loads, the maximum axial load is

maximum radial load

, the diameter along the bottom of the raceway of the upper ring is

mm, the diameter of the raceways of the lower rings is

mm, the radii of the grooves of the bearing rings

;

. The number of balls in the ball bearing is

.

The diameter of the balls was determined by the formula (1):

We check: with a minimum radius of the raceway profile

at the maximum radius of the raceway profile

Thus, in various picking groups, the ratio between the radius of the raceway profile and the diameter of the balls is the same and is within acceptable limits. If different ball diameters are used in different picking groups, as is usually used, then the ratio of the limits of fluctuation of the values of the ratio between the radii of the raceway profile and the diameter of the balls would go beyond the set limits, which would lead to abnormal operation of the bearing and a significant spread of the friction values in bearing and their load capacity. But since the actual load capacity of a batch of bearings is determined by its minimum value, then with the known method of picking, the load capacity of a batch of bearings would be lower than the calculated one.

We found the maximum ratio of radial and axial loads:

. Это значение получали при максимальной нагрузке на подшипник, при которой

.

. This value was obtained at the maximum bearing load at which

.

By the formula (2), the optimal picking angle was determined:

рад., или

glad., or

, под рабочей нагрузкой

при угле контакта

. Результаты измерения приведены в табл. 1.The diameters of the raceways of the upper and lower rings were measured with three balls:

under workload

at contact angle

. The measurement results are given in table. one.

The required difference in the diameters of the raceways was found in accordance with the formula (3):

The tolerance on the difference in the diameters of the raceways in each group was determined based on the permissible deviation of the contact angle from the optimal value of ± 1 ° (0.017 rad.):

Since the sum of the dispersion fields of the diameters of the raceways of the upper and lower rings was 0.319 mm and exceeded the tolerance on the difference in the diameters of the raceways, two dimensional groups of bearing rings were created for manning bearings. The first size group included the upper rings with diameters of the raceways within 77.643-77.723 and the lower rings with diameters of 72.197-72.276, and the second group included the upper rings with diameters of the raceways 77.724-77.804 and lower rings with diameters of 72.277-72.355.

As you can see, the static bearing capacity (Fig. 2) and torque (Fig. 3) depend significantly on the contact angle. The maximum static load capacity and minimum torque are provided when completing bearings with a contact angle of 57 degrees. If you deviate from this value in both directions, the indicated bearing capacity indicators decrease. Particularly sharply, the static load capacity drops, and the torque increases with an increase in the contact angle to 80 or more degrees. But standard angular contact bearings have a contact angle of 90 degrees, and therefore their load capacity is significantly lower than the bearing capacity of the bearings, equipped according to the proposed method with an optimal contact angle.

Thus, the proposed method of manning bearings ensures high accuracy of forming the contact angle in the bearing by dividing the rings into only two size groups using balls of the same size, which simplifies the manning process and ensures high bearing capacity, since the ratio between the radii of the raceway profile and the diameter of the balls does not change, and the formed contact angle provides a minimum load on the balls.

The technical and economic efficiency of the proposed method of completing ball bearings is as follows:

1. The bearing capacity increases due to their assembly with an optimal working angle of contact, which ensures a reduction in the load on the balls when the bearing is subjected to a real working load.

2. The stability of the bearing capacity indicators is increased, since in all size groups during picking one size of balls is used.

3. The acquisition process is simplified, since only bearing rings are divided into size groups.

Claims (1)

A method of completing ball bearings, including measuring the diameters of the raceways of the outer and inner rings at a contact angle under the action of an axial load, characterized in that the axial load uses a ball load equal to: P _k = A⋅z _k / z, while the diameter of the balls at picking is determined from the relation ds = (1.91 ÷ 1.92) ⋅ (rg _max + rg _min ) / 2, and the contact angle when measuring the diameters of the raceways is determined as

where P _k is the load at which the diameters of the raceways are measured, N; z _k - the number of balls that measure the diameters of the raceways; z is the number of balls in the assembled ball bearing; β _o - nominal contact angle in the bearing, provided during the picking process, rad .; Kr is the maximum value of the ratio of the radial R and axial A working loads on the bearing during operation; ds is the diameter of the picking balls, mm; rg _max and rg _min - the maximum and minimum allowable radii of the raceway profile, mm.

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