FR3017651A1 - TURBOMACHINE BEARING BEARING AND ASSOCIATED TURBOMACHINE - Google Patents

Description

TECHNICAL FIELD The present invention relates to the field of turbomachines, and more particularly to the general field of architecture of rolling bearings of a turbomachine. The invention applies to all types of land or aeronautical turbomachines, and in particular to aircraft turbomachines such as turbojets and turboprops. More preferentially, the invention can be applied to a double-body and dual-flow turbojet engine. It relates more precisely a rolling bearing turbomachine, and a turbomachine comprising at least one such bearing. STATE OF THE PRIOR ART In a turbomachine, the shafts connecting the different bodies of the turbomachine, for example a compressor and a turbine, must be able to rotate at very high speeds so that their mechanical strength is fundamental. Bearings that support them must remain rigorously rectilinear, in the axis of the engine, and must be able to withstand efforts of several tons and a minimum of unbalanced accidental. To do this, the bearings, consisting of ball or roller bearings, support these trees by relying on the fixed or movable members of the turbomachine. In order to contribute to the good performance of the engine and therefore its lower fuel consumption, the bearings and their bearings must produce a minimum of friction losses, and are therefore cooled and lubricated by oil circulation. Although cooled continuously, the bearings are however affected by the presence of hot zones related to the operation of the turbomachine, mainly the discs holding the blades.

Firstly, in stabilized operation, given the non-uniform temperature distribution, the shaft is subjected along its length at different levels of radial expansion, which entails the risk of a cone of the raceways of the inner rings. and / or outside of the bearing in operation. This is a generator of unreliability of the rolling bearing. Secondly, when the engine is stopped, the lubricating oil undergoes an increase in temperature on functional parts. This can generate a cooking of the lubricating oil, with accession to the functional parts. This phenomenon can lead to premature failure of the bearing.

DISCLOSURE OF THE INVENTION The object of the invention is therefore to remedy at least partially the needs mentioned above and the drawbacks relating to the embodiments of the prior art. The invention thus has, according to one of its aspects, a rolling bearing of a turbine engine supporting in rotation a first subassembly placed on the outer side with respect to a second subassembly placed on the inner side thus forming a bearing , and comprising a bearing provided with an inner ring mounted on the outer face of the second subassembly and an outer ring mounted on the inner face of the first subassembly, characterized in that a radial clearance is provided between the inner ring and the second subassembly, at the level of the bearing, and in that the fixing zone between the inner ring and the second subassembly is located downstream of the bearing so as to lengthen the heat conduction path inside the bearing. . Thanks to the invention, it may be possible to obtain an elongation of the thermal conduction path under the inner ring so as to thermally insulate it. In this way, it may be possible to at least partially overcome the risks of cone and cooking effect of the oil mentioned above. The bearing according to the invention may further comprise one or more of the following characteristics taken separately or in any possible technical combinations.

The first subset may be a first tree. Similarly, the second subset may be constituted by a second tree. The first and second subassemblies can thus form an inter-shaft bearing. The first subassembly can be constituted by a first shaft, in particular constituted by the trunnion downstream of the shaft line of the high-pressure body. The second subassembly may be constituted by a second shaft, in particular constituted by the downstream journal of the shaft line of the low-pressure body. The bearing can thus preferably be an inter-shaft bearing. The fixing zone between the inner ring and the second subassembly may be a hooping zone. In a variant, the zone of attachment between the inner ring and the second subassembly may be other. In particular, the fixing zone between the inner ring and the second subassembly may be a clamping zone. The invention further relates, according to another of its aspects, a turbomachine, characterized in that it comprises at least one rolling bearing as defined above. BRIEF DESCRIPTION OF THE DRAWING The invention will be better understood on reading the detailed description which follows, of an exemplary nonlimiting implementation thereof, as well as the examination of the single FIG. 1, schematic and partial, of the accompanying drawing, showing, in axial section, a turbomachine portion comprising an example of a rolling bearing according to the invention. The different parts shown in the figure are not necessarily in a uniform scale, to make the figure more readable.

DETAILED DESCRIPTION OF A PARTICULAR EMBODIMENT Throughout the description, it is noted that the terms upstream and downstream are to be considered with respect to a main direction F of normal gas flow (from upstream to downstream) for a turbomachine. Furthermore, the T-axis of the turbomachine is the axis of radial symmetry of the turbomachine. The axial direction of the turbomachine corresponds to the direction of the axis T of the turbomachine. A radial direction of the turbomachine is a direction perpendicular to the axis T of the turbomachine. In addition, unless otherwise stated, the adjectives and adverbs axial, radial, axially and radially are used with reference to the aforementioned axial and radial directions. In addition, unless otherwise stated, the terms inner and outer are used with reference to a radial direction so that the inner part of an element is closer to the T axis of the turbomachine than the outer part of the same element. FIG. 1 shows, in axial section, a part of a turbomachine 11 comprising an example of a rolling bearing 10 according to the invention. In this particular example, the first 1 and second 2 subsets respectively consist of first 1 and second 2 shafts, thus forming an inter-shaft bearing. However, this example is in no way limiting, and the first 1 and second 2 subsets could be defined otherwise. The turbomachine portion 11, shown in FIG. 1, thus comprises a first subassembly or shaft 1, which is the downstream trunnion of the shaft line of the high-pressure turbine engine body, and a second subset or shaft 2, which is the downstream trunnion of the shaft line of the low-pressure turbomachine body.

The first 1 and second 2 shafts are rotatably supported relative to each other by a bearing 3 of an inter-shaft bearing 10, the rolling elements 12, of rollers or balls 12, are inserted between an outer ring 5, mounted directly on the inner face 7 of the first shaft 1, and an inner ring 4, mounted on the outer face 6 of the second shaft 2, between the tracks of which they roll.

Furthermore, according to the invention, a radial clearance 8 is provided between the inner ring 4 and the second shaft 2, under the bearing 3, internally thereto. In addition, the attachment zone 9 between the inner ring 4 and the second shaft 2 is located downstream of the bearing 3. This fastening zone 9 is for example a hooping zone. Alternatively, in the case of not shown bearings mounted by flanges, the attachment zone 9 may also be a clamping zone.

In this way, it is possible to form an elongation of the heat conduction path C internally to the bearing 3, making it possible to guard against the thermomechanical stresses imposed by the operation of the rolling bearing 10 in a turbomachine 11 with a high thermal gradient and compact architecture.

Of course, the invention is not limited to the embodiment which has just been described. Various modifications may be made by the skilled person. In particular, the invention can be applied both to an inter-shaft bearing connecting first 1 and second 2 rotating shafts, and to a bearing connecting a mobile subset to a fixed subset.

Claims (7)

REVENDICATIONS1. Turbomachine rolling bearing (10) rotatably supporting a first subassembly (1) placed on the outer side with respect to a second subassembly (2) on the inner side thereby forming a bearing, and having a bearing (3) provided with an inner ring (4) mounted on the outer face (6) of the second subassembly (2) and an outer ring (5) mounted on the inner face (7) of the first subassembly (1) , characterized in that a radial clearance (8) is provided between the inner ring (4) and the second subassembly (2), at the level of the bearing (3), and in that the fastening area (9) between the inner ring (4) and the second subassembly (2) is located downstream of the bearing (3) so as to extend the heat conduction path internally to the bearing (3). 2. Bearing according to claim 1, characterized in that the first subassembly (1) is constituted by a first shaft (1), in particular constituted by the journal downstream of the shaft line of the high-pressure body. 3. Bearing according to claim 1 or 2, characterized in that the second subassembly (2) is constituted by a second shaft (2), in particular constituted by the downstream journal of the shaft line of the low-pressure body. 4. Bearing according to claims 2 and 3, characterized in that it is an inter-shaft bearing. Bearing according to one of the preceding claims, characterized in that the fastening region (9) between the inner ring (4) and the second subassembly (2) is a hooping zone. 6. Bearing according to one of claims 1 to 4, characterized in that the fastening zone (9) between the inner ring (4) and the second subassembly (2) is a clamping zone. 7. Turbine engine (11), characterized in that it comprises at least one rolling bearing (10) according to any one of the preceding claims.