FR3041721A1 - UNBALANCED AXIAL ROCKER DEVICE WITH DEVICE FOR ROD CLEARANCE BY A FIXED COMPONENT OF A ROTATING MACHINE - Google Patents

Abstract

An axial stop (100; 300) for a rotating machine (1; 2) comprising a fixed component (40; 220) and a component (20; 240) rotatable with respect to the fixed component comprises: a first ring (102; 302 ); a second ring (103; 303) comprising a first half-ring (103A; 303A) and a second half-ring (103B; 303B); oblique-contact rolling members (104; 304) disposed between the first ring and the second ring; a pre-load system (106; 306) exerting a predetermined axial force tending to bring the first half-ring (103A; 303A) and the second half-ring (103B; 303B) closer together; and characterized in that: the first ring (102; 303) is rotatably mounted on the rotary component and is configured to be selectively rotated by a synchronizing member (21; 241) of the rotating component (20; 240); ); the second half-ring (103B; 303B) is configured to be limited in axial displacement by the fixed component (40; 220).

Description

UNBALANCED AXIAL STOP DEVICE WITH RING DISPENSE DISPOSAL BY A FIXED COMPONENT OF A MACHINE

ROTARY

Background of the invention

The present invention relates to an axial stop for a rotating machine.

In the present description, "rotary machine" means any machine having a fixed component, and a rotary component relative to this fixed component.

In such a rotating machine, it is generally necessary to provide a mechanical axial abutment function of the rotating element. This function is generally provided by an axial abutment comprising an angular contact ball bearing. However, in certain applications, for example when the rotational speed of the rotary component is very high, this ball bearing is highly stressed and may wear prematurely. In some cases, when using a three- or four-point contact ball bearing, undesirable operating phases may occur where the balls operate with three contact points when the axial stop is axially loaded, such operation causing a very fast wear of the bearing.

To solve this problem, the Applicant has already proposed an axial abutment described in the patent document FR 3 003 913. The solution proposed in this document is based on the use of two preloading systems, one of which is located between two half-stops. rings of one of the rings of the abutment. This implies in particular to provide additional machining of the two half-rings to receive and maintain in place this additional preload system, and also requires the manufacture of the additional preload system. These additional machining and manufacturing steps tend to increase the complexity of the abutment and increase its cost.

It has been found that there is a need to simplify the axial abutment and to limit its manufacturing cost, avoiding the need for an additional preloading system located between two half-rings of the abutment.

Object and summary of the invention

To meet this need, the present invention provides an axial stop for a rotating machine comprising a fixed component and a rotatable component relative to the fixed component, comprising: a first ring; a second ring comprising a first half-ring and a second half-ring; oblique-contact rolling elements arranged between the first ring and the second ring; a pre-load system exerting a predetermined axial force tending to bring the first half-ring and the second half-ring; wherein: the first ring is rotatably mounted on the rotary component and is configured to be selectively rotated by a synchronizing member of the rotating component; the second half-ring is configured to be limited in axial displacement by the fixed component.

Since the second half-ring is limited in axial displacement by the fixed component, the two half-rings are held apart from each other when the first ring is rotated by the synchronizing element. Thus, it limits the appearance of an operating mode where the oblique contact elements operate with three points of contact with the rings, this mode of operation involving accelerated wear of the balls and rings which is detrimental to the service life of the bearing. Thus, the wear of the bearing is limited as in the patent document FR 3,003,913, but without additional cost induced by the presence of an additional pre-charge system between the two half-rings.

In addition, with this configuration, it eliminates the thermomechanical management of the gap between the two half-rings, because the second half-ring is mechanically limited in axial displacement by the fixed component, while the first half-ring is free to move axially depending on the operating mode of the stop.

According to one possibility, the second half-ring comprises a flange configured to be inserted into a groove of the fixed component.

This solution is simple and inexpensive to set up, both during the manufacture of the elements of the axial abutment that during its assembly.

Alternatively, it is also possible that the second half-ring forms part of the fixed component.

According to one possibility, the pre-load system exerts an axial force in the opposite direction to the axial load exerted by the rotary component via the synchronizing element when the first ring is rotated.

According to one possibility, the pre-load system defines a threshold value of axial load exerted by the rotary component via the synchronizing element when the first ring is rotated, the threshold value being such that an axial clearance between the first ring half-ring and the second half-ring is equal to a low threshold value (possibly zero) when said axial load is less than or equal to the threshold value, and is strictly greater than this low threshold value when said axial load is strictly greater than the threshold value. As soon as the threshold value is exceeded, the axial clearance between the two outer half-rings exceeds its low threshold value, that is to say that the two outer half-rings are spaced axially due to the limited axial displacement of the second half-ring. The bearing then works stably and can withstand high axial loads.

According to one possibility, the threshold value is furthermore chosen such that axial clearance between the second ring and the fixed component is zero when said axial load is strictly greater than the threshold value.

Thus, when the threshold value is exceeded, the axial clearance between the second ring and the fixed component is zero, that is to say that the second ring is in contact with the fixed component. The bearing can therefore support even greater axial loads.

According to one possibility, the pre-load system comprises one or more spring washers.

According to one possibility, the angular contact rolling elements are balls.

The present invention also relates to a rotary machine comprising an axial abutment according to any of the possibilities that have just been described. In particular, there is envisaged a rotating machine with fixed shaft and fixed housing, comprising an axial stop as described above, in which the stationary housing is the "fixed component" described above, and the rotating shaft is the "Rotary component" described above.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood and its advantages will appear better on reading the following detailed description of several embodiments, shown by way of non-limiting examples. The description refers to the accompanying drawings in which: - Figure 1 is a partial sectional view of an axial abutment according to a first embodiment of the invention, installed in a rotary machine with fixed housing, in a state where rotating shaft does not exert an axial load on the stop; - Figure 2 is a view similar to Figure 1, showing another mode of operation of the rolling contact elements; - Figure 3 is a view similar to Figure 1, in a clutch phase where the axial load exerted by the rotating shaft on the axial abutment is less than or equal to a threshold value; - Figure 4 is a view similar to Figure 1, in an operating phase where the axial load exerted by the rotating shaft on the axial stop is strictly greater than a threshold value; FIG. 5 is a view in partial section of an axial abutment according to a second embodiment of the invention, installed in a rotating machine with a fixed shaft, in a state where the rotating casing does not exert an axial load on stop ; - Figure 6 is a view similar to Figure 5, in a clutch phase where the axial load exerted by the casing rotating on the axial abutment is less than or equal to a threshold value; - Figure 7 is a view similar to Figure 5, in an operating phase wherein the axial load exerted by the rotating casing on the axial stop is strictly greater than a threshold value.

Detailed description of the invention

First embodiment

Firstly, with reference to FIGS. 1 to 4, a first embodiment of the invention will be described.

FIG. 1 represents, in partial section, an axial stop 100 according to the first embodiment of the invention, installed in a rotary machine with fixed casing 1. The rotating machine 1 comprises a stationary casing 40 and a rotating shaft 20. The fixed casing 40 thus forms a fixed component of the rotating machine, and the rotating shaft 20 forms a rotating component of the rotating machine. The rotating shaft 20 rotates inside the stationary casing 40 about an axis of rotation Al. Of course, the rotary machine 1 comprises other elements such as bearings to maintain the axis of rotation Al stable. also comprises that the axial stop 100, the fixed casing 40 and the rotating shaft 20 have an axial symmetry with respect to the axis A1, so that the figures represent only part of the axial abutment 100.

In the following, the terms "axial", "axially" and "axial displacement" will be understood as "parallel to the axis of rotation Al".

The axial abutment 100 comprises a first ring 102 and a second ring 103.

The first ring 102 is rotatably mounted around the rotating shaft 20, so as to be rotated about the axis of rotation A1.

As will be detailed below, in certain operating modes of the axial abutment 100, the first ring 102 can be rotated by the rotating shaft 20, via a synchronizing element 21 arranged on the rotating shaft 20. case, the first ring 102 rotates about the axis of rotation A1 in the same direction and at the same speed of rotation as the rotating shaft 20.

In other words, the axial stop 100 makes it possible to produce a disengageable axial abutment.

In the example shown in Figures 1 to 4, the synchronizing element 21 is a simple stop, but it can also be a synchronization cone or any other element capable of rotating the first ring 102 The surface of the first ring 102 intended to be in contact with the synchronizing element 21 has a shape adapted to ensure sufficient contact with the corresponding surface of the synchronizing element 21. For example, this surface of the first ring 102 has a shape substantially complementary to the corresponding surface of the synchronizing element 21.

The second ring 103 is mounted on the inner periphery of the fixed casing 40, and is not rotated during the different operating phases of the axial abutment 100.

Angular contact bearing elements 104 are arranged between the rings 102 and 103. For example, these angular contact rolling elements are balls circulating in internal tracks arranged in the rings 102 and 103. A cage 105 holds the elements of angular contact bearing 104 between the rings 102 and 103.

As can be seen in FIGS. 1 to 4, the second ring 103 comprises a first half-ring 103A and a second half-ring 103B, the second half-ring 103B being here the half-ring closest to the element axially. synchronization 21.

The second half-ring 103B is configured to be limited in axial displacement by the fixed casing 40. For example, the second half-ring 103B is fixed relative to the fixed casing 40. In the example shown in FIGS. 4, the second half-ring 103B comprises a flange 103B2 which is carried by an extension portion 103B1 and which is inserted, at the time of assembly, into a groove 45 formed in the fixed casing 40. As the flange 103B2 remains inserted in the groove 45, the second half-ring 103B is limited in axial displacement.

It may be provided that the housing 40 is divided into two housing portions 41 and 42, the groove 45 can then be located at the interface between the first portion 41 and the second housing portion 42, as shown in FIGS. 1 to 4. This possibility has the advantage of simplifying the manufacture and assembly of the axial abutment 100, and its installation in the rotary machine 1.

Instead of a configuration with flange and groove, it is also possible to limit the axial displacement of the second half-ring 103B by other means, such as fixing pins and screws. Alternatively, it is also possible for the second half-ring 103B to be an integral part of the fixed casing 40, for example of the second casing part 42.

The axial stop 100 also includes a pre-load system 106. For example, the pre-load system 106 comprises an elastic member, which may be one or more spring washers. The pre-load system 106 may for example be arranged in a housing 43 provided for this purpose on the first housing portion 41.

The pre-load system 106 exerts a predetermined axial force which tends to bring the first half-ring 103A and the second half-ring 103B closer to each other. In the example shown, the pre-load system 106 exerts an axial force on the first half-ring 103A, so that the first half-ring 103A tends to get closer to the second half-ring 103B, the second half 103B ring being limited in axial displacement by the fixed casing 40.

The pre-load system 106 defines a threshold value of axial load exerted by the rotating shaft 20, via the synchronization element 21, on the axial abutment 100. This threshold value depends in particular on the characteristics of the pre-load system 106. (For example, a stiffness constant of an elastic element) and internal dimensions of the elements of the axial stop 100, and is therefore determined during the dimensioning of the axial abutment 100.

As long as the axial load exerted by the rotating shaft 20 is less than or equal to the threshold value, an axial contact surface 123A located on the half-ring 103A and external to the axial stop 100 is not in contact with the housing In other words, an axial clearance S between the second ring 103 and the fixed casing 40 (in the example shown, between the first casing portion 41 and the first half-ring 103A) remains non-zero. In addition, an axial clearance I between the two half-rings 103A and 103B is equal to its low threshold value, this low threshold value may be zero or non-zero. In FIGS. 1 and 2, the low threshold value of the axial clearance I is zero, that is to say that the two half-rings 103A and 103B are in contact with one another via axial contact surfaces. 113A and 113B respectively internal to the ring 103.

The low threshold value of the axial play I can also be non-zero; in this case, the surfaces 113A and 113B are not in contact with each other, and there is always between these two surfaces an axial play at least equal to the low threshold value.

When the axial load becomes strictly greater than the threshold value, the axial clearance I becomes strictly greater than its low threshold value, and the axial clearance S is reduced and can become zero.

We will now explain in detail the different operating phases of the axial abutment 100.

In a first phase, illustrated in Figures 1 and 2, wherein the rotating shaft 20 exerts no axial load on the axial stop 100, the synchronizing element 21 is not in contact with the first ring 102, c that is to say that an axial clearance 110 between the synchronizing element 21 and the first ring 102 is non-zero. Therefore, the first ring 102 is not rotated. In addition, because of the axial force exerted by the pre-load system 106, the axial play I between the half-rings 103A and 103B is equal to its low threshold value. In FIGS. 1 and 2, the low threshold value of the axial clearance I is zero, that is to say that the half-rings 103A and 103B are in contact with one another via the contact surfaces 113A and 113B. As a result, the angular contact rolling elements 104 operate in a disengaged and non-rotational mode of operation. This operating mode may be a three-point or four-point mode of operation.

In order to prevent the first ring 102 from being undesirably rotated, for example by the fluid stirred by the rotating shaft 20, provision may be made for the bearing consisting of the first ring 102, the second ring 103, and oblique-contact rolling elements 104 have a slightly negative internal clearance. Such a negative internal clearance makes it possible to introduce into the rolling bearing a braking torque which is exerted on the rolling contact rolling elements 104, and to keep the rolling contact rolling elements 104 and the first ring 102 in place, so as to to prevent internal shocks (for example related to vibrations) that are harmful to the service life of the bearing. In this case, it is possible to obtain a three-point mode of operation, shown in FIG. 1, in which the oblique-contact rolling elements 104 have a point of contact P1 with the first half-ring 103A, a point of contact contact P3 with the second half-ring 103B, and a contact point P5 with the first ring 102.

It is also possible to obtain a mode of operation with four contact points, as represented in FIG. 2. The oblique-contact rolling elements 104 then have, for example, a point of contact PI with the first half-ring 103A, a point of contact P3 contact with the second half-ring 103B, and two contact points P2 and P4 with the first ring 102. In this case, the contact points PI and P2 are diametrically opposed, and the contact points P3 and P4 are diametrically opposed .

During the first phase, the axial clearance S is non-zero.

We now consider a second phase, called "clutch phase", in which the rotating shaft 20 exerts an increasing axial load on the axial stop 100. The rotating shaft 20 moves in the axial direction towards the axial stop 100. The axial clearance 110 decreases to zero. Because of the contact between the synchronizing element 21 and the first ring 102, the first ring 102, and thus the rolling contact rolling elements 104, are rotated by the rotating shaft 20 via the synchronizing element 21. , so that the axial stop 100 functions as a bearing. As long as the axial load is less than or equal to the threshold value, the axial force exerted by the pre-load system 106 counteracts the effects of the axial load, so that the axial play I remains at its low threshold value. As soon as the axial load exceeds the threshold value, the first half-ring 103A slides axially, while the second half-ring 103B is limited in axial displacement by the fixed casing 40. Thus, the axial clearance I between the two half-rings becomes strictly greater than its low threshold value and increases, while the axial clearance S decreases, as illustrated in FIG.

In a third phase of operation where the axial load remains strictly greater than the threshold value, the axial clearance I remains strictly greater than its low threshold value. The angular contact rolling elements 104 are no longer in contact with the second half-ring 103B and operate in two points of contact. In the two-point mode of operation, the angular contact rolling elements 104 have a contact point PI with the first half-ring 103A, and a contact point P2 with the first ring 102, the contact points PI and P2 being diametrically opposed. In this phase of operation, the bearing is able to withstand a greater axial load than when the oblique contact elements 104 operate in three or four contact points. Optionally, as shown in Figure 4, the axial clearance S is zero, that is to say that the first half-ring 103A is pressed on the fixed casing 40. The bearing can then support an axial load even more important.

The fact that the second half-ring 103B is limited in axial displacement makes it possible to limit or prevent the occurrence of undesired contact between the oblique-contact rolling elements 104 and the second half-ring 103B when the abutment is undergoing an axial load. In other words, the occurrence of an unwanted phase of operation where the oblique-contact rolling elements 104 operate at three points of contact (i.e., two points of contact with the first ring 102 and the first half-ring 103A, and a third undesirable contact point with the second half-ring 103B) is limited or prevented by the spacing of the half-rings 103A and 103B. This phase of operation is detrimental to the life of the bearing.

The present invention thus provides a simplified and less costly configuration of axial abutment, to improve the life of the bearing. In addition, since the appearance of a third undesirable contact point with the second half-ring 103B is avoided thanks to the spacing of the half-rings 103A and 103B, it is possible to allow less stringent tolerances for internal tracks. provided on the rings 102 and 103, which further reduces the cost of the axial abutment.

It should be noted that the threshold value can be adjusted according to the axial load ranges expected during the nominal operation of the rotating machine, for example by suitably selecting the characteristics of the pre-load system 106. It will also be understood that it is preferable to choose a threshold value as low as possible, to promote operation in the third phase.

Note further that the maximum value of the axial clearance S between the half-ring 103 and the housing 40 can be adjusted during assembly of the axial stop. Therefore, the maximum value of the axial play I, which depends directly on the axial play S, can also be adjusted.

Finally, consider a fourth phase of operation of the axial stop, called "disengagement phase", during which the axial load exerted by the shaft on the stop decreases to zero.

When the axial load becomes less than or equal to the threshold value, because of the axial force exerted by the pre-load system 106, the axial clearance S increases again, and the two half-rings 103A and 103B tend to bring closer, that is to say that the axial play I decreases. Here too, since the half-ring 103B is limited in axial displacement, the oblique-contact rolling elements 104 only come into contact with the half-ring 103B for a very brief or non-existent transient period during which the bearing is still rotated before the stop returns to the disengaged state illustrated in Figures 1 and 2. Thus, the undesired period of operation at three points of contact is of very limited duration or zero.

Finally, when the axial load is zero, the axial clearance 110 becomes non-zero, and the axial play I becomes equal to its low threshold value. The bearing returns to an operating mode with three or four points of contact. The internal friction rolling then slow the rotation of the first ring 102 and the rolling contact rolling elements 104 until the complete stop thereof. In the absence of such a slowdown of the rolling friction internal thereto, the fluid used to lubricate the bearing continues to drive the rolling contact elements 104 due to its inertia, which can negatively affect the life of the bearing.

Second embodiment

An axial stop 300 according to a second embodiment of the invention, applicable to a rotating machine with a fixed shaft 2, will now be described, based on FIGS. 5 to 7.

With respect to the first embodiment, the respective roles of the shaft and the housing, and the first and second rings, are reversed, while the other elements are unchanged and therefore designated by the same reference signs as those used for the first embodiment, incremented by 200.

According to the second embodiment, the rotating machine 2 therefore comprises a fixed shaft 220 and a rotating casing 240. The fixed shaft 220 thus forms a fixed component of the rotary machine, and the rotating casing 240 forms a rotary component of the machine. rotating. The rotating housing 240 rotates about an axis of rotation Al coincides with the longitudinal axis of the fixed shaft 220.

The axial abutment 300 comprises a first ring 302 and a second ring 303. The first ring 302 is mounted free to rotate and can be rotated by the rotating casing 240, in the same direction and at the same speed of rotation as it, via a synchronizing element 241 mounted on the rotating housing 240. The second ring 303 is mounted on the side of the fixed shaft 220 and is not rotated during the various phases of operation of the bearing. The second ring 303 comprises two half-rings 303A and 303B similar to the half-rings 103A and 103B of the first embodiment.

It will be noted that, contrary to the first embodiment, the rotating casing 240 exerts an axial load on the first ring 302, and the second half-ring 303B is limited in axial displacement by the fixed shaft 220. As for the first embodiment of FIG. realization, this limitation in axial displacement can be obtained by means of a flange 303B2 carried by an extension portion 303B1, or by means of pins or screws, or by providing that the second half-ring 303B is an integral part of the fixed shaft 220.

Axial abutment 300 also includes a pre-load system 306 that performs the same function as pre-load system 106 of the first embodiment.

The principle of operation of the axial abutment 300 is identical to that of the axial abutment 100 and will therefore not be described in detail. In particular, as shown in FIGS. 6 and 7, the axial abutment 300 has the same axial clearances I and S as the axial abutment 100, and these axial clearances vary identically in both embodiments.

The axial abutment 300 provides, for a machine with rotating casing and fixed shaft, the same advantages as in the first embodiment. In particular, the axial stop 300 has an operating mode with three or four contact points and a mode of operation with two contact points, such as the axial stop 100.

The operating mode with three or four contact points can be obtained when the rotating housing 240 does not exert an axial load on the axial stop 300 via the synchronizing element 241.

In the case where the bearing has a negative internal clearance as in the first embodiment, it is possible to obtain a three-point mode of operation, shown in FIG. 5, in which the oblique-contact rolling elements 304 have a PI contact point with the first half-ring 303A, a point of contact P3 with the second half-ring 303B, and a point of contact P5 with the first ring 302.

It is also possible to obtain, as in the first embodiment, a mode of operation with four contact points (not shown), in which the oblique-contact rolling elements have a point of contact PI with the first half-ring 303A. a contact point P2 with the second half-ring 303B, and two contact points P3 and P4 with the first ring 302. In this case, the contact points PI and P2 are diametrically opposed, and the contact points P3 and P4 are diametrically opposed.

The mode of operation with two contact points is obtained when the axial load exerted by the rotating casing 240 via the synchronizing element 241 on the axial abutment 300 remains strictly greater than the threshold value defined by the precharge system 306.

In the two-point mode of operation, the angular contact rolling elements 304 have a contact point PI with the first half-ring 303A, and a contact point P2 with the first ring 302, the contact points PI and P2 being diametrically opposed. In this operating phase, the bearing is able to withstand a greater axial load than when the oblique contact elements 304 operate in three or four points of contact.

As the axial abutment 100 of the first embodiment, the axial abutment 300 allows, because the second half-ring 303B is limited in axial displacement by the fixed shaft 220, to limit or prevent the occurrence of an undesirable phase of operation where the oblique-contact rolling elements 304 operate in three points of contact (i.e., two points of contact with the first ring 302 and the first half-ring 303A, and a third point of undesirable contact with the second half-ring 303B) when the axial abutment 300 undergoes axial load, this transient phase being detrimental to the life of the bearing.

Although the present invention has been described with reference to specific exemplary embodiments, it is obvious that modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. In addition, individual features of the various embodiments mentioned can be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than restrictive sense.

Claims (10)

An axial stop (100; 300) for a rotating machine (1; 2) comprising a fixed component (40; 220) and a component (20; 240) rotatable with respect to the stationary component, comprising: a first ring (102; 302); a second ring (103; 303) comprising a first half-ring (103A; 303A) and a second half-ring (103B; 303B); oblique-contact rolling members (104; 304) disposed between the first ring and the second ring; a pre-load system (106; 306) exerting a predetermined axial force tending to bring the first half-ring (103A; 303A) and the second half-ring (103B; 303B) closer together; characterized in that: the first ring (102; 302) is rotatably mounted on the rotary component and is configured to be selectively rotated by a synchronizing member (21; 241) of the rotating component (20; 240); the second half-ring (103B; 203B) is configured to be limited in axial displacement by the fixed component (40; 220). The axial stopper of claim 1, wherein the second half-ring comprises a flange (103B2; 303B2) configured to be inserted into a groove (45; 225) of the fixed component. The axial stopper of claim 1, wherein the second half-ring (103B; 303B) forms a portion of the fixed component (40; 220). Axial stopper according to any one of claims 1 to 3, wherein the pre-load system (106; 306) exerts an axial force in the opposite direction to the axial load exerted by the rotary component via the synchronization (21; 241) when the first ring (102; 302) is rotated. An axial stopper according to any one of claims 1 to 4, wherein the precharge system (106; 306) defines an axial load threshold value exerted by the rotary component via the synchronizing member (21) when the first ring (102; 202) is rotated, the threshold value being such that an axial clearance (I) between the first half-ring (103A; 303A) and the second half-ring (103B; 303B) is equal at a low threshold value when said axial load is less than or equal to the threshold value, and is strictly greater than this low threshold value when said axial load is strictly greater than the threshold value. Axial stopper according to claim 5, wherein the threshold value is such that an axial clearance (S) between the second ring (102; 302) and the fixed component (40; 220) is zero when said axial load is strictly greater than the threshold value. 7. Axial stopper according to any one of claims 1 to 6, wherein the pre-load system (106; 306) comprises one or more spring washers. Axial stopper according to any one of claims 1 to 7, wherein the oblique-contact rolling elements (104; 304) are balls. 9. Rotating machine (1; 2) comprising an axial stop according to any one of claims 1 to 8. 10. Rotating machine (1) according to claim 9, wherein the fixed component is a fixed housing (40), and the rotary component is a shaft (20) rotating inside the fixed housing.