WO2021130456A1

WO2021130456A1 - Mechanical roller bearing with ogival tracks

Info

Publication number: WO2021130456A1
Application number: PCT/FR2020/052612
Authority: WO
Inventors: Laurent Schweitzer; Laurent Paul François PERROT
Original assignee: Safran Aircraft Engines
Priority date: 2019-12-24
Filing date: 2020-12-22
Publication date: 2021-07-01
Also published as: FR3105320A1; FR3105320B1

Abstract

The invention relates to an assembly (100) for a rolling bearing, comprising: - a bearing (20) having an axis of rotation (X-X) and comprising an inner ring fastened to a shaft (1) and an outer ring fastened to a hub (2), - an annular inner intra-bearing spacer (7) arranged between the inner ring and the shaft (1), - an annular outer intra-bearing spacer (6) arranged between the outer ring and the hub (2), in which at least one of the inner intra-bearing spacer (7) and the outer intra-bearing spacer (6) has a coefficient of thermal expansion at least 10% greater than the coefficient of expansion of one or more parts surrounding the inner intra-bearing spacer (7) and/or the outer intra-bearing spacer (6).

Description

DESCRIPTION

TITLE: Mechanical rolling bearing with ogival tracks Technical field of the invention

The invention relates to the field of rolling bearings and more particularly rolling bearings having ogival tracks.

State of the prior art

In mechanical machines such as cryogenic pumps and turbines for turbomachines, the pivot connections between rotating elements and fixed elements can be provided by bearings.

A conventional bearing 10 is shown in Figure 1, which is arranged to ensure the rotation of a shaft 1 having an axis of rotation, for example a shaft of a turbine relative to a fixed casing 2 of the turbine. The bearing 10 comprises an outer ring 3 formed by two half-rings and arranged tight against the housing 2. The bearing 10 also comprises an inner ring 4 formed by two half-rings and arranged tight against the shaft 1. A plurality of rolling elements such as balls are arranged between the outer ring and the inner ring distributed circumferentially around the axis of rotation.

Each of the inner ring and of the outer ring is kept fixed in translation in the direction of the axis of rotation by nuts 5 screwed respectively onto the shaft 1 and the housing 2. FIG. 2 is an enlargement of the bearing 10 showing the arrangement of the balls 6 in contact with the inner and outer rings, in particular with a first half-ring 3a and a second half-ring 3b of the outer ring 3. The half-ring 3a has an arcuate section in a plane transverse of the bearing 10 having a first radius Re1 and a first center 01. Likewise, the half-ring 3b has an arcuate section in the transverse plane of the bearing 10 having a second radius Re2 and a second center 02. The first radius Re1 and the second radius Re2 are identical and the half- rings 3a and 3b are arranged so that the first center 01 and the second center 02 are not the same but are arranged at a distance called the thickness of the shim Ep from each other. Thus, the inner ring and the outer ring comprising the half-rings 3a and 3b each have the general shape of an ogive in the transverse plane.

The axial and radial position of centers 01 and 02 as well as the value of radii Re1 and Re2 have a great influence on the preload and internal loads at bearing 10, as well as on the management of the axial and radial clearances specific to bearing 10 .

During the operation of the bearing 10, significant loads or temperature variations can cause the appearance of play deviations causing contact fatigue. abnormal, displacements in undesired directions or amplitudes, sliding bearings, and / or vibratory unbalance.

It is therefore necessary to find a compromise on the geometry of the inner and outer rings to maintain an acceptable axial and radial play during operation of the bearing and to ensure a minimum axial and radial play for each operating condition.

Summary of the invention

One of the aims of the invention is to remedy the aforementioned problems.

Another object of the invention is to provide a bearing reducing the axial play of the shaft in most cases of operation.

Another object of the invention is to provide a more reliable and more efficient bearing.

To this end, the invention proposes a set for a bearing comprising:

- a bearing having an axis of rotation comprising an inner ring fixed to a shaft and an outer ring fixed to a hub, each of the inner ring and of the outer ring being formed by two adjacent half-rings,

- an internal annular intra-bearing spacer arranged between the internal ring and the shaft,

an annular outer intra-bearing spacer arranged between the outer ring and the hub, in which at least one, in particular each, of the internal intra-bearing spacer and of the outer intra-bearing spacer has a coefficient of thermal expansion of at least 10% greater or less than the coefficient of expansion of one or more surrounding parts of the inner intra-bearing spacer and / or the outer intra-bearing spacer.

The difference in the thermal coefficient between the internal and external intra-bearing spacers and the parts arranged around these spacers generates a controlled preload in the bearing and also makes it possible to modify the clearance of the bearing. Thus, these thermal deformations make it possible to adjust the axial and radial play of the bearing as well as its internal preload to adapt to the operating loads of the bearing. The proposed assembly is therefore more reliable and more efficient.

According to one embodiment, at least one, in particular each, of the internal intra-bearing spacer and of the external intra-bearing spacer may have a stiffness coefficient of at least 70% greater than the stiffness coefficient. of one or more surrounding rooms. The assembly may include an outer nut screwed into the hub and holding the fixed outer ring in translation in the direction of the axis of rotation.

The assembly may further include an inner nut screwed into the shaft and holding the outer ring fixed in translation in the direction of the axis of rotation.

According to one embodiment, the coefficient of thermal expansion of at least one, in particular each, of the internal intra-bearing spacer and of the external intra-bearing spacer may be at least 10% greater than coefficient of expansion of one or more parts, when the assembly is subjected to high temperatures, for example a temperature greater than 50 ° C, in particular greater than 100 ° C, and more particularly greater than 500 ° C.

According to one embodiment, the coefficient of thermal expansion of at least one, in particular each, of the internal intra-bearing spacer and of the external intra-bearing spacer may be at least 10% less than coefficient of expansion of one or more parts, when the assembly is subjected to low temperatures, for example a temperature below -50 ° C, in particular below -100 ° C, and more particularly below -150 ° C.

According to one embodiment, the assembly may include an outer extra-bearing spacer arranged between the outer ring and a shoulder provided in the hub, and an inner extra-bearing spacer arranged between the inner ring and the inner nut.

In this case, at least one, in particular each, of the internal extra-bearing spacer and of the external extra-bearing spacer has a coefficient of thermal expansion of at least 10% greater than the coefficient of expansion of l. 'one or more surrounding rooms.

According to one embodiment, the coefficient of expansion of at least one, in particular each, of the internal extra-bearing spacer and of the external extra-bearing spacer may be at least 10% greater than the coefficient expansion of one or more parts, when the assembly is subjected to high temperatures, for example a temperature greater than 50 ° C, in particular greater than 100 ° C, and more particularly greater than 500 ° C.

According to one embodiment, the coefficient of expansion of at least one, in particular each, of the internal extra-bearing spacer and of the external extra-bearing spacer may be at least 10% less than the coefficient expansion of one or more parts, when the assembly is subjected to low temperatures, for example a temperature below -50 ° C, in particular below -100 ° C, and more particularly below -150 ° C.

According to one embodiment, at least one, in particular each, of the internal extra-bearing spacer and of the external extra-bearing spacer has a stiffness coefficient of at least 70% greater than the stiffness coefficient of l. 'one or more surrounding rooms.

According to one embodiment, each, or at least one, of the internal extra-bearing spacer and of the external extra-bearing spacer may have a variable length in the direction of the axis of rotation, said assembly comprising means for controlling said variable length.

According to one embodiment at least one, in particular each, of the internal intra-bearing spacer, of the external intra-bearing spacer, of the internal extra-bearing spacer and of the external extra-bearing spacer has a coefficient of thermal expansion of at least 10% to 20% greater than the coefficient of expansion of one or more surrounding parts.

According to another embodiment, at least one, in particular each, of the internal intra-bearing spacer, of the external intra-bearing spacer, of the internal extra-bearing spacer and of the external extra-bearing spacer has a coefficient of thermal expansion equal to twice the coefficient of expansion of one or more surrounding parts.

Surrounding parts may include one of: inner ring, outer ring, inner nut, outer nut, shaft and / or hub, rolling element.

The outer ring may include a recess provided to receive the outer intra-bearing spacer.

The inner ring may include a recess provided to receive the inner intra-bearing spacer.

Brief description of the figures

Figure 1, already described, shows a mechanical bearing assembly known from the state of the art.

Figure 2, already described, shows an enlarged view of a bearing and a rolling element of the mechanical bearing assembly of Figure 1.

Figure 3 shows a first embodiment of a bearing assembly according to the invention, seen in section in a transverse plane of the bearing.

Figure 4 shows a second embodiment of a bearing assembly according to the invention, seen in section in a transverse plane of the bearing.

Detailed description of the invention

Referring to Figure 3, the bearing assembly 100 comprises a bearing 20 having an axis of rotation XX mounted between a shaft 1, for example a turbine shaft connecting a low pressure compressor to a turbine, and a fixed support 2, for example a turbine housing. In particular the bearing 20 comprises an outer ring formed by two outer half-rings 4a and 4b mounted tight in the fixed support 2. The bearing 20 further comprises an inner ring formed by two inner half-rings 3a and 3b mounted tight against the 'tree 1. The outer ring is kept motionless in translation along the axis of rotation X-X by an outer nut 5b. The outer nut 5b is screwed into the fixed support 2 against the outer ring which abuts against a shoulder 101 provided in the fixed support 2. The inner ring is also kept motionless in translation along the axis of rotation XX by a nut. internal 5a. The inner nut 5a is screwed onto the shaft 1 against the inner ring which abuts against a shoulder 102 provided in the shaft 1.

A plurality of rolling elements such as balls 11 are arranged between the outer ring and the inner ring distributed circumferentially around the axis of rotation. The bearing assembly 100 further comprises an annular outer intra-bearing spacer 6 arranged in an annular recess provided in the outer half-rings 4a and 4b. In particular, the external intra-bearing spacer 6 bears, in a first direction S1 of the direction of the axis of rotation XX, on an annular shoulder face 4a1 of one of the outer half-rings 4a, 4b which defines, in the direction of the axis of rotation XX, a first end of the annular recess provided in the outer half-rings 4a, 4b.

Likewise, the outer intra-bearing spacer 6 bears, in a second direction S2 of the direction of the axis of rotation XX, on an annular shoulder face 4b1 of the other of the outer half-rings 4a, 4b which defines, in the direction of the axis of rotation XX, a second end of the annular recess provided in the outer half-rings 4a, 4b. The annular shoulder face 4a1, 4b1 of each of the outer half-rings 4a, 4b is here normal to the direction of the axis of rotation X-X.

The bearing assembly 100 further comprises an internal annular intra-bearing spacer 7 arranged in an annular recess provided in the internal half-rings 3a and 3b. In particular, the internal intra-bearing spacer 7 bears, in the first direction S1 of the direction of the axis of rotation XX, on an annular shoulder face 3a1 of one of the internal half-rings 3a, 3b which defines, in the direction of the axis of rotation XX, a first end of the annular recess provided in the internal half-rings 3a, 3b. Likewise, the internal intra-bearing spacer 7 bears, in the second direction S2 the direction of the axis of rotation XX, on an annular shoulder face 3b1 of the other of the internal half-rings 3a, 3b which defines, in the direction of the axis of rotation XX, a second end of the annular recess provided in the internal half-rings 3a, 3b. The annular shoulder face 3a1, 3b1 of each of the inner half-rings 3a, 3b is here normal to the direction of the axis of rotation X-X.

The outer intra-bearing spacer 6 and the internal intra-bearing spacer 7 are qualified by the term “intra-bearing” in that they each have here a role of spacer in the direction of the axis of rotation XX . In other words, the outer intra-bearing spacer 6 and the inner intra-bearing spacer 7 each maintain a spacing in the direction of the axis of rotation XX, respectively, between the outer half-rings 4a, 4b and between the inner half-rings 3a, 3b. Thus, remarkably, there is an annular clearance j1 in the direction of the axis of rotation X-X between the outer half-rings 4a, 4b. Likewise, there is clearance j2 in the direction of the axis of rotation X-X between the inner half-rings 3a, 3b.

Furthermore, as shown in Figure 3, an annular clearance j3 can be formed in the radial direction between the outer intra-bearing spacer 6 and each outer half-ring 4a,

4b, and an annular clearance j4 can be formed in the radial direction between the internal intra-bearing spacer 7 and each internal half-ring 3a, 3b. The outer intra-bearing spacer 6 is here mounted to bear radially outwardly on a radially inner surface of the fixed support 2. Likewise, the internal intra-bearing spacer 6 is here mounted to bear radially inwardly on a radially outer surface of the shaft 1. The internal 7 and external 6 intra-bearing spacers each have a coefficient of thermal expansion greater / or less than at least 10% of the coefficient of thermal expansion of the surrounding parts such as the internal half-rings 3a and 3b, half-rings 4a and 4b, of the shaft 1 and of the fixed support 2. In particular, the thermal expansion coefficient of each of the internal 7 and external 6 intra-bearing spacers is 10% to 20% higher or lower than the thermal expansion coefficient surrounding rooms. For example, the coefficient of thermal expansion of each of the internal 7 and external 6 intra-bearing spacers may be equal to twice the thermal expansion coefficient of the surrounding parts.

For example, the coefficient of thermal expansion of each of the internal 7 and external 6 intra-bearing spacers is 10% to 20% greater than the coefficient of thermal expansion of the surrounding parts when the assembly is subjected to a temperature greater than 100 ° C. . For example, the coefficient of thermal expansion of each of the internal 7 and external 6 intra-bearing spacers is 10% to 20% less than the coefficient of thermal expansion of the surrounding parts when the assembly is subjected to a temperature below -100 ° vs. In particular, the material and the shape of the internal 7 and external 6 intra-bearing spacers are chosen to obtain such coefficient of thermal expansion and coefficient of rigidity.

The difference in the thermal coefficient between the internal 7 and external 6 intra-bearing spacers and the parts arranged around these spacers generates a controlled preload in the bearing and also makes it possible to modify the clearance of the bearing. Thus, these thermal deformations make it possible to adjust the axial and radial play of the bearing as well as its internal preload to adapt to the operating loads of the bearing. The assembly of Figure 3 is therefore more reliable and more efficient.

Alternatively, such spacers could be applied only to the inner ring or the outer ring.

FIG. 4 represents a second example of a bearing assembly 200 comprising the same elements as the bearing assembly 100 of FIG. 3. In addition, the bearing assembly 200 comprises an external extra-bearing spacer 8 which is annular and arranged between the outer ring of the bearing 20 and a shoulder 201 provided in the fixed support 2. Unlike the bearing assembly 100 of Figure 3, the outer ring does not rest against the shoulder 101 but against the extra spacer external bearing 8.

The bearing assembly 200 comprises an internal extra-bearing spacer 9 which is annular and arranged between the inner ring of the bearing 20 and the nut 5. Unlike the bearing assembly 100 of FIG. 3, the outer ring does not rest. not directly against the nut but against the internal extra-bearing spacer 9. Unlike the bearing assembly 100 of Figure 3, the two inner half-rings can be slidably mounted.

Unlike the bearing assembly 100 in Figure 3, the two outer half-rings can be slidably mounted.

The outer 8 and inner 9 extra-bearing spacer each has a variable length passively, for example under the influence of temperature.

As a variant, the outer 8 and inner 9 extra-bearing spacer each has a variable length in an active manner under the effect of an actuator, for example a linear motor, arranged in the bearing assembly 200, not shown in the figure. 4.

In addition, the external 8 and internal 9 extra-bearing spacers may have thermal expansion coefficients identical to the thermal expansion coefficients of the internal 3 and external 4 intra-bearing spacers.

The external 8 and internal 9 extra-bearing spacers can also have stiffness coefficients identical to the stiffness coefficients of the internal 3 and external 4 intra-bearing spacers.

Claims

1. Set (100,200) for a bearing comprising:

- a bearing (20) having an axis of rotation (XX) and comprising an inner ring fixed to a shaft (1) and an outer ring fixed to a hub (2), each of the inner ring and the outer ring being formed by two adjacent half-rings (3a, 3b; 4a, 4b),

- an internal annular intra-bearing spacer (7) arranged between the internal ring and the shaft (1),

- an annular outer intra-bearing spacer (6) arranged between the outer ring and the hub (2), in which at least one of the internal intra-bearing spacer (7) and of the outer intra-bearing spacer (6) has a coefficient of thermal expansion of at least 10% greater or less than the coefficient of expansion of one or more surrounding parts of the internal intra-bearing spacer (7) and / or of the intra-bearing spacer external (6).

2. Assembly according to claim 1, wherein at least one of the internal intra-bearing spacer (7) and of the external intra-bearing spacer (6) has a stiffness coefficient of at least 70% greater. the stiffness coefficient of one or more surrounding parts.

3. An assembly according to claim 1 or 2, wherein the coefficient of thermal expansion of at least one of the inner intra-bearing spacer (7) and of the outer intra-bearing spacer (6) is at least 10% greater than the coefficient of expansion of one or more parts, when the assembly is subjected to high temperatures, preferably a temperature greater than 50 ° C, preferably greater than 100 ° C, preferably greater than 500 ° vs.

4. The assembly of claim 1 or 2, wherein the coefficient of thermal expansion of at least one of the inner intra-bearing spacer (7) and of the outer intra-bearing spacer (6) is at least 10% less than the coefficient of expansion of one or more parts, when the assembly is subjected to low temperatures, preferably a temperature below -50 ° C, preferably below -100 ° C, preferably below -150 ° C.

5. An assembly (100,200) according to any one of the preceding claims, comprising an outer nut (5b) screwed into the hub and holding the fixed outer ring in translation in the direction of the axis of rotation (X-X).

6. Assembly (200) according to any one of the preceding claims, comprising an internal nut (5a) screwed into the shaft and maintaining the fixed external ring in translation in the direction of the axis of rotation (XX).

7. The assembly (200) of claim 6, comprising an outer extra-bearing spacer (8) arranged between the outer ring and a shoulder provided in the hub, and an inner extra-bearing spacer (9) arranged between the inner ring and the internal nut (5a), in which at least one of the internal extra-bearing spacer (9) and of the external extra-bearing spacer (8) has:

- a coefficient of thermal expansion of at least 10% greater or less than the coefficient of expansion of one or more surrounding parts.

8. The assembly (200) of claim 7, wherein each of the extra internal bearing spacer (8) and the outer extra-bearing spacer (9) has a variable length in the direction of the axis of rotation ( XX), said assembly comprising means for controlling said variable length.

9. An assembly (200) according to claim 7 or 8, wherein at least one of the internal intra-bearing spacer (7), of the outer intra-bearing spacer (6), of the extra-spacer. internal bearing (9) and the outer extra-bearing spacer (8) has a coefficient of thermal expansion of at least 10% to 20% greater than the coefficient of expansion of one or more surrounding parts.

10. An assembly (200) according to any one of claims 7 to 9, wherein at least one of the internal intra-bearing spacer (7), of the outer intra-bearing spacer (6), of the The internal extra-bearing spacer (9) and of the external extra-bearing spacer (8) has a thermal expansion coefficient equal to twice the expansion coefficient of one or more surrounding parts.

11. An assembly (100,200) according to claims 5 and 6, wherein the surrounding parts comprise one of: the inner ring, the outer ring, the inner nut (5a), the outer nut (5b), elements. bearing arranged between the inner ring and the outer ring, the shaft (1) and / or the hub (2).

12. An assembly (100,200) according to any preceding claim, wherein the outer ring comprises a recess provided to receive the outer intra-bearing spacer.

13. An assembly (100,200) according to any preceding claim, wherein the inner ring comprises a recess provided to receive the internal intra-bearing spacer.