RU2235227C2 - Spherical roller bearing - Google Patents

Abstract

FIELD: mechanical engineering; antifriction bearings.

SUBSTANCE: in proposed spherical roller bearing containing outer race with spherical path, inner race with three toroidal paths, three rows of barrel-shaped rollers installed so that axis of rollers of middle row is parallel to axis of bearing, and axes of rollers of extreme rows are inclined through angle to bearing axis and diameter of middle path is less than diagonal size between middles of extreme paths and cylindrical belts are made on inner race between middle and extreme paths. Bearing contains two cages per three rows of rollers.

EFFECT: increased load capacity and speed of rotation.

3 cl, 1 dwg

Description

The invention relates to the field of engineering, in particular to rolling bearings.

Known spherical roller double row bearing of a normal series of widths from the SKF Catalog "Groβ e Lager Katalog 4003T", page 396, for example bearing 22228 CC / W33. The bearing contains an outer ring with a spherical raceway, an inner ring with two toroidal raceways, two rows of barrel-shaped rollers installed in the separator / 1 /.

The ratio of the roller length Lw to its diameter Dw for such bearings is 0.8 ... 1.0, due to which they have low friction and high speed, but are not able to absorb a large load.

A spherical roller double row bearing of a particularly wide series of widths is known from the SKF Catalog "Groβ e Lager Katalog 4003T", page 398, for example, bearing 24130 CC / W33. The bearing contains an outer ring with a spherical raceway, an inner ring with two toroidal raceways, two rows of barrel-shaped rollers installed in the separator / 1 /.

The ratio of the length of the roller Lw to its diameter Dw for such bearings is 1.4 ... 1.6, due to which they have an increased load capacity, however, this also entails an increase in friction and a low speed.

Known spherical roller bearing according to the USSR AS No. 1995575. The bearing contains the outer and inner rings with raceways, two rows of barrel-shaped rollers, the axes of which are located at an angle to the axis of the bearing. In order to increase bearing capacity, the bearing has a third row of rollers whose axes are parallel to the axis of the bearing. Each row of rollers is placed in a separate separator, and on the inner ring there are two middle beads with fillets that separate the middle and extreme raceways / 2 /.

Due to the introduction of the third row of rollers, the ratio of the roller length Lw to its diameter Dw for such bearings is 0.8 ... 1.0, due to which they have low friction and high speed, while being able to absorb large loads.

In this bearing, the diameter of the middle raceway is equal to the diagonal size between the midpoints of the outer raceways. From which it follows that the averaged radial clearance Gr is the same in all rows of rollers. This leads to the fact that due to technologically unavoidable random errors in the dimensions of the raceways during operation of the bearing, the raceways are loaded unevenly (one or both extreme rows remain unloaded), which entails overloading of the working rollers and, therefore, reduces the reliability and durability bearing.

In addition, the presence of two middle sides with fillets on the inner ring complicates the manufacture of the bearing, and fillets reduce the working length of the rollers, which leads to a reduction in load capacity by up to 25% compared to a double-row bearing of an extra wide series of widths.

Installing each row of rollers in a separate cage also complicates the design of the bearing.

The problem to which this invention is directed, is the creation of a bearing with high load capacity and high speed, which eliminates the overload of the rollers and having a simpler design.

This problem is solved in that in a spherical roller bearing containing an outer ring with a spherical raceway, an inner ring with three toroidal raceways, three rows of barrel-shaped rollers installed so that the axis of the rollers of the middle row is parallel to the axis of the bearing, and the axis of the rollers of the outermost rows are tilted at an angle to it, the diameter of the middle raceway of the inner ring is smaller than the diagonal size between the midpoints of its extreme raceways. On the inner ring between the middle and extreme raceways are made cylindrical belts. The bearing contains two cages for three rows of rollers.

The drawing shows a cross section of a spherical roller bearing according to the invention.

Spherical roller bearing contains: outer ring 1 with spherical raceway 2; the inner ring 3 with three toroidal raceways 4, 5, 6 and two cylindrical belts 7, separating the middle 5 and extreme 4, 6 raceways; three rows of barrel-shaped rollers 8, 9, 10, mounted so that the axis O ₃ -O _{3 of the} rollers 9 of the middle row is parallel to the axis of the bearing OO, and the axes O ₁ -O ₁ and O ₂ -O _{2 of the} rollers 8, 10 of the outermost rows are respectively inclined to it at an angle α; two separators 11 and 12, the separator 11 holding the roller 8 and half the length of the roller 9, and the separator 12 - the roller 10 and half the length of the roller 9.

Since the bearing contains three rows of rollers, the ratio of the length of the roller Lw to its diameter Dw is the optimum value of 0.8 ... 1.0.

The relationship between the diameter d _{3 of the} middle raceway 5 of the inner ring 3 and the diagonal dimensions d ₁ and d ₂ between the midpoints of the outer raceways 4 and 6 of the inner ring 3, respectively, is determined by the relationship:

d ₃ ≤ d ₁ -2b _y = d ₂ -2b _y , (1)

where b _y is the elastic deformation in the contacts: raceway 2 of the outer ring 1 - roller (8, 9, 10) - raceway (4, 5, 6) of the inner ring 3 or otherwise the axes of the inner 3 and outer 1 rings approach the external Fr load on the bearing. For the most efficient use of the bearing, the load Fr is taken from the condition:

0,02С ≤ Fr≤ 0,05С, (2)

where C is the dynamic design bearing capacity.

Based on the theory of elasticity, b _y is determined by the formula:

Where

Ze is the total number of rollers in the bearing;

Lw is the effective length of the roller;

α is the angle of inclination of the axes of the rollers of the extreme rows;

Fr - bearing load; can fluctuate within 0 ... 0,2С.

Since the diameter d _{3 of the} middle raceway 5 of the inner ring 3 is smaller than the diagonal dimensions d ₁ and d ₂ between the midpoints of the outer raceways 4 and 6 of the inner ring 3, respectively, based on formula (1), the relationship between the averaged radial gaps Gr _{cp of the} average a number of rollers 9 and Gr _{cr of the} extreme rows of rollers 8 and 10 has the form:

Gr _cr + b0.02C <Gr _cp , (4)

where b0.02C is the total elastic deformation in the contacts of the most loaded rollers with the outer and inner rings at a load of 0.02C.

Thus, the average radial clearance Gr _cp in the middle row of rollers 9 is greater than the clearances Cr _cr in the extreme rows of rollers 8 and 10.

The bearing works as follows: the initial unloaded condition is characterized by the fact that under the influence of the own weight of the outer ring 1, cages 11 and 12, rollers 4, 5, 6, two dimensional chains are closed: the housing (not shown) - raceway 2 of the outer ring 1 - a roller 8 is a raceway 4 of the inner ring 3 is a mechanism shaft (not shown) and: a housing (not shown) is a raceway 2 of the outer ring 1 is a roller 10 is a raceway 6 of the inner ring 3 is a mechanism shaft (not shown).

In this case, the force applied from the shaft to the housing is distributed between the extreme raceways 4, 6 of the inner ring 3 and, accordingly, the extreme rows of rollers 8, 10.

The middle row of rollers 9, due to the increased clearance, does not contact the raceways 2, 5 of the outer 1 and inner 3 rings, respectively, and does not transfer the load. When light loads are applied (0.02-0.05 dynamic load rating C), the bearing, thanks to the Lw / Dw ratio of 0.8 ... 1.0, works as a two-row bearing of a normal series of widths, has low friction and a high speed. When large loads are applied (0.05-0.2 dynamic load rating C) due to elastic deformation of the contacts: outer ring 1 - roller 9 - inner ring 3, an additional clearance is selected, and the bearing starts to work as a two-row bearing of an extra wide series of widths, i.e., its load capacity increases, while overloading the rollers is excluded.

The absence of middle edges on the inner ring 3, as well as the installation of two cages 11, 12 on three rows of rollers 8, 9, 10 simplifies the manufacture of the bearing.

Sources of information

1. SKF catalog "Groβ e Lager Katalog 4003T". Reg. 47.12000, 1993-04.

2. Copyright certificate of the USSR No. 199575, cl. 47b, 12. Publ. 1967.

Claims (3)

1. A spherical roller bearing comprising an outer ring with a spherical raceway, an inner ring with three toroidal raceways, three rows of barrel-shaped rollers mounted so that the axis of the rollers of the middle row is parallel to the axis of the bearing, and the axis of the rollers of the outermost rows are angled to it, characterized in that the diameter of the middle raceway of the inner ring is smaller than the diagonal dimension between the midpoints of its extreme raceways, d3≤d1-2b _y = d2-2b _y , where d3 is the diameter of the middle raceway of the inner ring; d1, d2 - diagonal size between the midpoints of the extreme raceways of the inner ring; b _y - elastic deformation in the contacts: raceway of the outer ring - roller - raceway of the inner ring or otherwise the axes of the inner and outer rings approach the external load on the bearing. 2. The bearing according to claim 1, characterized in that on the inner ring between the middle and extreme raceways made cylindrical belts. 3. The bearing according to claim 1, characterized in that the bearing contains two cages on three rows of rollers.