RU2269684C2 - Antifriction bearing - Google Patents

Abstract

FIELD: mechanical engineering, instrumentation and other industries.

SUBSTANCE: proposed radial-thrust antifriction single-row bearing has inner and split outer races with rolling elements in between made in form of single-step rollers installed in cage. Larger diameter of roller larger step made spherical is in contact only with two roller paths of split outer race of bearing in two point at angle of contact α, and smaller diameter of roller steps is in contact only with two roller paths of bearing inner race in two points to provide rolling of rolling elements both over outer and inner roller paths at constant and equal speed without slipping. Roller path of bearing inner race is provided with ring groove and it forms clearances with larger diameter or roller larger step. Smaller diameter of roller steps is made cylindrical, and it is provided with spherical sections at end faces in contact with roller paths of bearing inner race at angle of contact β.

EFFECT: increased service life of bearing owing to elimination of slipping of rolling elements.

1 dwg

Description

The invention relates to the field of mechanical engineering and instrumentation, and can also be used in all industries.

Known rolling bearings containing inner and outer rings with raceways, the rolling bodies located between them, made in the form of balls or rollers installed in the nests of the separator.

The main disadvantage of the known rolling bearings is, along with rolling friction, the presence of rolling friction with slipping of the rolling elements relative to the raceways:

- slippage of the rolling elements relative to the raceways caused by shear deformation of the material at the point of contact;

- sliding of the rolling elements relative to the raceways, in case of violation of rolling as a result of shifts and distortions of the bearing rings under load (see P.I. Orlov book 2. Design fundamentals, -M .: Mechanical Engineering, 1977, p.453. ..460).

For example, take a single-row angular contact ball bearing with a split outer ring with a four-point contact No. 116220 according to GOST 8995-75, for which d100 × D180 × B34; Dw25.4; Z = 14; α = 26 °; Nk = 4000 min ^-1 ; Nzh = 5000 min ^-1 . Ball ⌀25.4 rolls along the chord with ⌀23 mm along the raceways of the bearing. On the outer raceways with ⌀163 mm, the ball is rolled in in one revolution of the shaft:

N revolutions = π163 / π23 = 7.086.

And on the raceways of the inner ring with ⌀117 mm, the ball makes in one revolution of the shaft:

N revolutions = π117 / π23 = 5.086.

That is, along the raceways of the outer ring of the bearing, the ball makes two turns more than along the raceways of the inner ring of the bearing. This value is equal to the value of the ball slipping in the bearing for only one revolution of the shaft. And balls - Z = 14 and each slips two turns for one revolution of the shaft.

And, if the bearing makes 4000 min ^-1 , all the balls in a minute will make extra turns:

N = 14 × (4000 × 2) = 112000 min ^-1 .

These extra revolutions of the balls in the bearing require a significant oil consumption to maintain operability and other devices to reduce the temperature of the assembly. In general, this provision reduces the bearing life.

Analogues for this proposed invention are applications No. 2001119832 and No. 2002107654.

The purpose of the invention:

- Ensuring a clean rolling of the rolling elements when they are run along the raceways of both the inner and outer rings of the bearing;

- increase the limit speed of the rolling bearing, for example, up to 50,000 min ^-1 or more;

- in general, to increase the durability of the bearing, only by eliminating the slip of rolling elements;

- ensure the operation of the bearing in extreme conditions in the absence of lubricant supply, for example, up to 90 min.

The goals and technical effect of the present invention is achieved due to the fact that the smaller diameter of the steps of the roller is made cylindrical and contains spherical sections to its ends, the latter are in contact with the raceways of the inner ring of the bearing at an angle β, and under extreme conditions the bearing is able to work even in the absence of lubricant supply, for example, up to 90 min, due to the passport for each rolling bearing.

The drawing shows a rolling bearing angular contact single row with a detachable outer ring with four-point contact of the rolling elements with raceways. The direction of perceived loads is radial and axial in both directions up to 70% of unused permissible radial load. With this radial clearance, the smallest axial clearance of the bearing is determined.

A rolling bearing of this type has been developed, for example, for use in gyroscopes. The rolling bearing consists of a split outer ring 1, rolling elements 2, cage 3, inner ring 4. The rolling elements 2 are made in the form of a single-stage roller, the larger diameter of the larger side of the roller is made spherical and contacts only with the raceways D _{1m of the} outer ring 1 at two points the diameter of the roller D _wm2 with a contact angle α (α is from 12 ° to 36 °). A smaller diameter of the steps of the roller 2 is made cylindrical, and has spherical sections at its ends, the latter contacting at the points (in two places) only with the raceways of the inner ring 4 at a diameter of d _1m with their diameters D _wm1 with a contact angle β (β from 12 ° up to 36 °, as an example). Moreover, an annular groove is made on the inner ring 4 to form a gap with a larger diameter of the larger stage of the roller 2, as well as to provide end gaps with side surfaces of a larger diameter of the larger stage of the roller 2. The last condition is necessary to prevent contact with sliding friction between the roller and ring 4.

The rolling bearing shown in the drawing, operates as follows. When the shaft rotates, the inner ring 4 rotates, the step roller 2 with its smaller diameter of the smaller steps D _wm1 rolls along the raceways with a diameter d _{1m of the} inner ring 4. The larger diameter of the larger step of the roller 2 rolls around with its diameter D _wm2 along the raceways with the diameter D _{1m of the} outer rings 1. In this case, it is necessary that the assembly condition is met:

D _1m / D _wm2 = d _1m / D _wm1 = Const.

It should be noted here that this condition allows the rolling bodies 2 to run on the outer and inner raceways with a constant and the same speed without slipping.

It should be noted separately that the value of Const should lie in the range from 2 to 3 + Δ for rolling bearings, for example, used in gyroscopes.

Why? So that fewer rolling elements work in the bearing when Z is from 5 to 7. And why again? A small value of Const from 2 to 3 + Δ reduces the maximum contact pressure by increasing the diameters D _wm2 and D _wm1 . An increase in the value of Const, for example, from 7 or more equalizes the values of D _wm2 and D _{wm1 of the} diameters of the stepped roller 2, the load increases, the number of rolling bodies increases, and the speed decreases.

This rolling bearing can be used in the gyro assembly.

Traditionally, the gyroscope is mounted on two, or even four, rolling bearings. We offer to install one bearing under the gyroscope disk, and install the shaft pins (consoles) motionless. Such a solution will significantly reduce the dimensions of the gyro assembly as a whole.

The rotation frequency in the proposed bearing can be significantly increased, for example, from 50,000 to 150,000 min ^-1 or more, if vibration is created in the bearing bearings with a high frequency and small amplitude.

"... It is known that during vibration, the friction moment in the bearings decreases from 3 to 10 times. The friction moment is less, the higher the frequency and the smaller the amplitude of the vibrations during vibration (the friction moment decreases by 100 ... 200 times ...). .. "(see. Yu. D. Pervitsky. Calculations and design of precise mechanisms". Ed. Mechanical Engineering, Moscow, 1965, Leningrad, p. 404).

In extreme conditions, the rolling bearing is able to work for a long time and in the absence of lubrication, only due to the presence of rolling friction when rolling the rolling elements along the raceways without slipping. This provision must be confirmed by tests on a specific bearing and entered in the passport on the bearing, for example, 90 minutes. All bearings that are installed in critical units are subject to certification: the airplane propeller, airplane landing gear, helicopter gearbox, engine, gas turbine, 40MW electric motor ...

The absence of slipping of the rolling elements significantly increases the bearing life due to the reduction of heat generation and noise of operation (and in the presence of balls as rolling elements, the ball will “yaw” inevitably and it constantly changes its race track). Operation noise is reduced due to the radial clearance, which is ≈ 0 in the angular contact bearing. Rolling bodies in the bearing do not have sliding contact with their ends with the lateral surfaces of the annular groove of the inner ring of the bearing.

The value of elastic hysteresis in the contact zone of a larger diameter of a larger roller stage is reduced due to a decrease in the value of Const (equal from 2 to 3 + Δ). It should be noted that the contact angles α and β can be made equal in magnitude, but can be different, depending on operating conditions, for example, α = β, a> b and α <β.

The presence of sliding friction of the roller with the separator material was preserved, but, if possible, it was minimized due to the introduction of separator centers in the design. Rollers can be made of minerals (sapphire, cubic zirconia, etc.) for non-magnetic rolling bearings.

Claims (1)

The rolling bearing is angular contact single row, containing an inner and split outer ring, the rolling elements placed between them, made in the form of single-stage rollers installed in a separator, the larger diameter of the larger roller stage, made spherical, contacts only two raceways of the split outer bearing ring in at two points at an angle of contact α, a smaller diameter of the steps of the roller is in contact with only two raceways of the inner ring of the bearing at two points, while Bearing assembly condition: D _1m / D _wm2 = d _1m / D _wm1 = Const, where D _1m is the diameter of the raceways of the outer ring of the bearing; D _wm2 is the larger diameter of the greater step of the roller; d _1m is the diameter of the raceways of the inner ring of the bearing; D _wm1 - smaller diameter of the steps of the roller, to ensure rolling of the rolling bodies along the outer and inner raceways with a constant and the same speed without slipping, and the raceway of the inner ring of the bearing is made with an annular groove and forms gaps with a larger diameter of the larger step of the roller, characterized in that the smaller diameter of the steps of the roller is made cylindrical , and to its ends contains spherical sections in contact with the raceways of the inner ring of the bearing at the contact angle β.