Device for guiding shaft and cooling bearing of gas generator

Abstract

The invention relates to a device (28) for guiding a shaft (20) about an axis (X) for a gas generator, comprising:-a rolling bearing (22); a lubrication circuit (26) for lubricating the rolling bearing (22); -an annular housing (42) extending around the bearing (22) and comprising an inner recess (44) for mounting the outer ring (22b); -a cooling circuit (28) for cooling the outer ring (22b) of the bearing (22), the cooling circuit comprising:-at least one annular fluid supply chamber (50) formed in the wall thickness (E) of the housing (42); -at least one annular fluid discharge chamber (52, 52a, 52b) formed in the wall thickness (E) of the housing (42); and-an annular system (40) for cooling the outer ring (22b), the annular system being connected to the supply and discharge chambers (50, 52, 52a, 52b), respectively.

Description

Technical Field

[0001] The invention relates to a device for guiding a shaft and cooling a bearing of a gas generator, such as a turbine or an auxiliary power unit. Background Art

[0002] The prior art includes, in particular, documents FR-A1-3 098 560, CN-B-110 905 653 and DE-A1-102016 211569.

[0003] In this application, a gas generator is considered to be a machine that, in that order, comprises at least one compressor, a combustion chamber, and at least one turbine. Air is compressed in the compressor, mixed with fuel, and combusted in the combustion chamber. The resulting combustion gases expand in at least one turbine, which drives the rotor of the at least one compressor. The two rotors can be fixed to each other.

[0004] There are a variety of gas generator applications and technologies. For example, a gas generator can be a turbine, particularly for an aircraft, and can include one or more bodies, each including a shaft connecting a compressor rotor to a turbine rotor. The turbine can be a turbojet, turboprop, or similar engine. A gas generator can also be an auxiliary power unit, also known as an APU (Auxiliary Power Unit), which can be installed on an aircraft, for example.

[0005] The rotor and the shaft of the gas generator are centered and guided in rotation by bearings, each bearing comprising two rings, an inner ring and an outer ring, between which rolling elements such as balls or rollers are mounted, for example.

[0006] These guide bearings require lubrication during operation and are therefore associated with a lubrication circuit, typically using oil.

[0007] These guide bearings must also be cooled to dissipate the heat generated during operation. There are several ways to achieve this.

[0008] One solution is to use lubricating oil to cool the bearings. A bearing lubrication circuit is the lubrication and cooling circuit for the bearings.

[0009] However, this solution has its drawbacks. This circuit requires specialized systems such as pumps, oil tanks, filters, and air / oil exchangers to remove the heat from the oil to the outside. Characterizing the volume, flow rate, temperature, and caloric content of this lubrication will determine the power of the pump, the dimensions of the reservoir, heat exchanger, and filter, as well as the use of certain materials (regarding the temperature reached by the oil).

[0010] Another solution is to use a bearing lubrication and cooling circuit that uses only fuel instead of oil. This last solution is not optimal because the fuel used to lubricate the bearings can be contaminated by particles produced by bearing wear. This contaminated fuel is unsuitable for the combustion chamber injectors (due to the risk of clogging them) and must therefore be discharged into the exhaust without being used for propulsion.

[0011] Another solution is to provide two separate, independent circuits for lubricating and cooling the bearings. The lubrication circuit can use oil, and the cooling circuit can use fuel, thus avoiding contact with the rolling elements. The fuel used to cool the bearings is heated by heat exchange with the bearings and can then be redirected to the combustion chamber for propulsion, thereby extending the flight envelope and increasing payload capacity.

[0012] The present invention provides an improvement which avoids at least some of the disadvantages of the prior art and which is simple, effective and economical. Summary of the Invention

[0013] The invention relates to a device for guiding a shaft about an axis and cooling the bearings of a gas generator, said device comprising:

[0014] a rolling bearing centered on the axis and comprising an inner ring, an outer ring and rolling elements arranged between these rings,

[0015] - a lubrication circuit for lubricating said rolling bearings,

[0016] an annular housing extending around the bearing and comprising an inner recess for mounting the outer ring, the housing comprising a wall thickness measured radially with respect to the axis, and

[0017] a cooling circuit for cooling the outer ring of the bearing, said cooling circuit being independent of the lubrication circuit,

[0018] Characterized in that the cooling circuit comprises:

[0019] at least one cooling fluid supply duct and at least one cooling fluid discharge duct, the at least one cooling fluid supply duct and the at least one cooling fluid discharge duct being formed in the wall thickness of the housing,

[0020] at least one annular fluid supply chamber extending around the axis and formed in the wall thickness of the housing, the annular chamber being connected to the at least one supply duct,

[0021] at least one annular fluid discharge chamber extending around the axis and formed in the wall thickness of the housing, the annular chamber being connected to the at least one discharge duct, and

[0022] an annular system for cooling the outer ring, connected respectively to the supply and discharge chambers, comprising at least one fluid channel extending along the axis and opening with a radial component inwards into the recess of the outer ring.

[0023] One of the characteristics of the guide device according to the present invention is that its lubrication and cooling circuits are independent. In this application, these circuits are independent because the fluid used to cool the bearings is not used to lubricate the bearings (although the fluid used to lubricate the bearings can be used to cool the bearings). The lubricating and cooling fluids are advantageously different. In particular, the fluids are not intended to mix at the bearings.

[0024] Another feature of this device is that the cooling circuit of the bearing is formed essentially within the thickness of the housing, which is therefore optimized in terms of overall dimensions. This thickness is not necessarily constant and can vary along the axis.

[0025] Finally, another advantageous feature of the device is that one or more fluid channels open into the inner recess of the outer ring and extend in the axial direction. The opening of the one or more channels in the inner recess enables the cooling fluid to come into direct contact with the outer ring, which optimizes cooling of the outer ring through both direct contact and convection. The axial component of the orientation of the one or more channels allows the cooling fluid to have a limited travel distance when in contact with the outer ring, thereby reducing the risk of heating the fluid at this point of contact. For example, this orientation is superior to a circumferential orientation around the ring, in which the fluid could be heated without effectively cooling the ring.

[0026] The device according to the present invention may include one or more of the following features, taken alone or in combination with each other:

[0027] - the system comprises: a single fluid channel having an annular shape around the axis;

[0028] - said single channel is empty;

[0029] - the single channel is filled with a honeycomb structure; the honeycomb structure is preferably a three-dimensional lattice structure, for example of the type described in applications FR-A1-3 096 110 or FR-A1-3 100 728;

[0030] - the single channel is connected to the supply chamber via a first series of orifices formed in the housing and to the discharge chamber via a second series of orifices formed in the housing;

[0031] - the single channel comprises an annular bottom facing the outer ring and having a convexly curved shape in axial cross section;

[0032] - the supply chamber and the discharge chamber are symmetrical with respect to a plane perpendicular to the axis;

[0033] - the system comprises a plurality of fluid channels distributed around the axis;

[0034] - the supply lumen is a single supply lumen extending around the fluid channel;

[0035] - the fluid channel is arranged between the first discharge chamber and the second discharge chamber;

[0036] - the supply chamber is connected to the first discharge chamber and the second discharge chamber through all the fluid channels;

[0037] - the supply chamber is connected to the first discharge chamber via a first fluid channel and to the second discharge chamber via a second fluid channel interposed between the first fluid channels;

[0038] - the first discharge chamber and the second discharge chamber are symmetrical with respect to a plane perpendicular to the axis;

[0039] - each of the supply chamber and the discharge chamber forms or comprises one or more volutes around the axis;

[0040] - each of the supply duct and the discharge duct extends mainly parallel to the axis;

[0041] --The lubrication circuit is an oil circuit,

[0042] --The cooling circuit is a fuel circuit,

[0043] The device comprises a heat exchanger comprising a first portion connected to the lubrication circuit and a second portion connected to the cooling circuit, and the heat exchanger is configured to ensure caloric exchange between the lubrication fluid and the cooling fluid.

[0044] The invention also relates to a gas generator comprising at least one device as described above, the gas generator being for example a turbine or an auxiliary power unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Further features and advantages will become apparent from the following description of non-limiting embodiments of the invention with reference to the accompanying drawings, in which:

[0046] [ Figure 1 ] Figure 1 is a very schematic diagram of a gas generator equipped with a guiding and cooling device according to the invention;

[0047] [ Figure 2 ] Figure 2 is a schematic perspective view of an axial cross section of a guiding and cooling device according to a first embodiment of the present invention;

[0048] [ Figure 3 ] Figure 3 yes Figure 2 A schematic perspective view of an axial cross section of the guide and cooling device shown without the rolling bearing and the shaft it guides;

[0049] [ Figure 4 ] Figure 4 The cooling fluid Figure 2 a schematic perspective view of a 270° axial cross section of the flow volume in the device shown;

[0050] [ Figure 5 ] Figure 5 yes Figure 2 A schematic diagram of an axial cross section of the device;

[0051] [ Figure 6 ] Figure 6 is a schematic perspective view of an axial cross section of a guiding and cooling device according to a second embodiment of the present invention;

[0052] [ Figure 7 ] Figure 7 yes Figure 6 A schematic perspective view of an axial cross section of the guide and cooling device shown without the rolling bearing and the shaft it guides;

[0053] [ Figure 8 ] Figure 8 yes Figure 6 A schematic diagram of an axial cross section of the device;

[0054] [ Figure 9 ] Figure 9 The cooling fluid Figure 6 a schematic perspective view of a cutaway 270° axial cross section of the flow volume in the device shown;

[0055] [ Figure 10 ] Figure 10 The cooling fluid Figure 6 a schematic perspective view of a 270° partial axial cross section of the flow volume in the device shown;

[0056] [ Figure 11 ] Figure 11 The cooling fluid Figure 6 a schematic perspective view of an axial cross section of the flow volume in the device shown;

[0057] [ Figure 12 ] Figure 12 is a schematic perspective view of an axial cross section of a guiding and cooling device according to a third embodiment of the present invention;

[0058] [ Figure 13 ] Figure 13 yes Figure 12 A schematic perspective view of an axial cross section of the guide and cooling device in FIG, without the rolling bearing and the shaft it guides;

[0059] [ Figure 14 ] Figure 14 The cooling fluid Figure 12 a schematic perspective view of a 270° axial cross section of the flow volume in the device shown;

[0060] [ Figure 15 ] Figure 15 yes Figure 12 A schematic diagram of an axial cross section of the device;

[0061] [ Figure 16 ] Figure 16 is a schematic perspective view of an axial cross section of a guide and cooling device according to a fourth embodiment of the present invention;

[0062] [ Figures 17a-17c 17a to 17c are schematic diagrams of an annular cavity in the form of a volute of a guide and cooling device according to the present invention;

[0063] [ Figures 18a-18b ] Figures 18a and 18b are very schematic views of the connection between the pipe and the annular cavity of the guiding and cooling device according to the invention. DETAILED DESCRIPTION

[0064] Figure 1 is a very general and schematic representation of a gas generator 10 , such as a turbine or an auxiliary power unit (APU), which may be fitted on board an aircraft, for example.

[0065] The gas generator 10 comprises at least one compressor (not shown), an annular combustion chamber 12 and at least one turbine 14. The combustion chamber 12 comprises a fuel injector 15.

[0066] The turbine 14 includes a bladed rotor 16 that rotates inside a stator. Combustion gases 18 flowing through the flow path of the turbine 14 expand and drive the rotor 16, which is connected to a shaft 20. The shaft 20 connects the rotor 16 of the turbine 14 to the rotor of a compressor, for example.

[0067] The shaft 20 is centered and guided in rotation about the axis X by one or more roller bearings 22 , such as ball bearings or roller bearings.

[0068] In the context of the present invention, the rolling bearing 22 forms part of a guide and cooling arrangement 24 , which also includes a bearing lubrication circuit 26 and a bearing cooling circuit 28 .

[0069] The lubrication circuit 26 is preferably an oil circuit. The circuit 26 comprises a reservoir 30 of lubricating fluid (oil), the outlet 30a of which is connected by a pump 32, for example via an air / oil heat exchanger 36, to at least one oil nozzle 34. The nozzle 34 is configured to spray the oil onto the bearing 22.

[0070] The reservoir 30 of the circuit 26 also comprises an inlet 30 b connected to at least one oil recovery element at the bearing 22 .

[0071] The cooling circuit 28 is independent of the lubrication circuit 26 and preferably uses a different fluid, such as fuel. The circuit 28 includes a cooling fluid or heat transfer fluid (fuel) reservoir 36, the outlet 36a of which is connected via a pump 38 to an inlet 40a of a system 40 for cooling the bearing 22. The system 40 includes an outlet 40b that can be connected to one or more injectors 15 so that the fuel that has been used to cool the bearing 22 can then be used to supply the combustion chamber 14.

[0072] Thus, the fuel is heated before being supplied to the chamber 12, which is advantageous. Furthermore, the heat absorbed by the fuel is not absorbed by the oil, so the oil is not too hot, which improves the efficiency of lubrication and can reduce the size of the heat exchanger 36 in the sense that the size of the heat exchanger is reduced.

[0073] Within the meaning of the present invention, the cooling system 40 also forms, together with the bearing 22 , part of the guide and cooling device 24 .

[0074] In certain embodiments of the present invention, the circuit 28 may also include a heat exchanger (not shown).

[0075] Although Figure 1Although not visible, bearing 22 includes two rings, an inner ring and an outer ring, with rolling elements, such as balls or rollers, disposed between the inner and outer rings. In the context of the present invention, cooling system 40 is configured to cool the outer ring of bearing 22 by bringing the outer ring of bearing 22 into direct contact with the fuel, thereby enabling direct heat exchange between the outer ring of bearing 22 and the fuel.

[0076] Now refer to Figures 2 to 5 , Figures 2 to 5 A first embodiment of the present invention is shown.

[0077] Figures 2 to 5 The guiding and cooling device 24 comprises:

[0078] a rolling bearing 22 having an inner ring 22a, an outer ring 22b and rolling elements 22c arranged between these rings 22a, 22b,

[0079] - lubrication circuit for rolling bearings (not shown, but corresponding to e.g. Figure 6 26),

[0080] an annular housing 42 extending around the bearing 22 and comprising an inner recess 44 for mounting the outer ring 22 b , this housing 42 comprising a wall thickness E measured radially with respect to the axis X, and

[0081] A circuit 28 for cooling the outer ring 22 b of the bearing, which circuit 28 is independent of the lubrication circuit and is partially shown.

[0082] The wall thickness E of the housing 42 is not constant and may vary from a minimum thickness E1 to a maximum thickness E2.

[0083] In the illustrated example, housing 42 includes an inner cylindrical surface 42a having a diameter D1 and an inner cylindrical surface 42b having a diameter D2, which is smaller than D1. A recess 44 of outer ring 22b is located inboard of surface 42a and near the junction between surfaces 42a, 42b. This junction forms an annular shoulder 42c, against which outer ring 22b, once installed, is shaped to bear axially. Inner ring 22a is mounted on shaft 20 and can also bear axially against shoulder 20a on shaft 20. In the illustrated embodiment, shaft 20 and housing 42 are axially arranged relative to each other such that shoulders 20a, 42c lie in the same plane perpendicular to the shaft, and rings 22a, 22b, have the same axial length. Rings 22a, 22b can be axially secured against shoulders 20a, 42c by screwing nuts onto shaft 20 and into housing 42, respectively.

[0084] The cooling circuit 28 comprises:

[0085] at least one cooling fluid supply duct 46 and at least one cooling fluid discharge duct 48 formed in the wall thickness E of the housing 42 ,

[0086] at least one annular fluid supply chamber 50 extending around the axis X and formed in the wall thickness E, this annular chamber 50 being connected to the supply duct(s) 46 ,

[0087] at least one annular fluid discharge chamber 52 extending around the axis X and formed in the wall thickness E, this annular chamber 52 being connected to one or more of said discharge ducts 48 , and

[0088] An annular system 40 for cooling the outer ring 22 b , which is connected to a supply chamber 50 and a discharge chamber 52 , respectively.

[0089] In the example shown, the circuit 28 comprises a single supply duct 46. This duct 46 has an elongated shape along the axis X and comprises a longitudinal end connected to and opening into a cavity 50. Figure 4 As shown, the conduit 46 is generally rectangular in cross-section, for example.

[0090] The supply chamber 50 is situated on one side of the cooling system 40 and is more precisely arranged between the duct 46 and the system 40. As in the example shown, the chamber 50 can have a substantially triangular or trapezoidal shape in axial cross section, thus having a fluid passage cross section that varies along the axis X and in particular decreases along this axis from the duct 46 to the system 40.

[0091] The discharge cavity 52 is located on the opposite side of the cooling system 40. As in the example shown, the cavity 50 may have a generally triangular or trapezoidal shape in axial cross section, thus having a fluid passage cross section that varies along the axis X and in particular increases along this axis from the duct 46.

[0092] From the accompanying drawings, especially Figure 5 It can be seen that the cavities 50, 52 can be symmetrical with respect to a plane H which is perpendicular to the axis X and passes between the cavities 50, 52 ( Figure 5 ).

[0093] In the example shown, the circuit 28 comprises a single exhaust duct 48. This duct 48 has an elongated shape along the axis and comprises a longitudinal end that is angled and connected to a cavity 52 and opens into this cavity 52. Figure 4 As shown, the duct 48 has, for example, a substantially rectangular cross-sectional shape. The figures also show that the ducts 46, 48 can be arranged one above the other and thus intersect the same plane passing through the axis X ( Figure 5).

[0094] The cavity 50 is connected to the cooling system 40 via a first series of orifices 58, which are preferably evenly distributed around the axis X. These orifices 58 are primarily axially oriented, but may also be inclined, for example, in a tangential or radial direction. In the example shown, the orifices 58 are inclined radially inwards from the end of the orifice 58 connected to the cavity 50 to the end of the orifice 58 connected to the system 40.

[0095] The number of these orifices 58 is greater than thirty, for example.

[0096] The cavity 52 is connected to the cooling system 40 via a second series of orifices 60, preferably uniformly distributed around the axis X. These orifices 60 are oriented primarily axially, but may also be inclined, for example, in a tangential or radial direction. In the example shown, the orifices are inclined radially inwards from the end thereof connected to the cavity 52 to the end thereof connected to the system 40.

[0097] The openings 58, 60 are also relative to the plane H ( Figure 5 ) are arranged symmetrically.

[0098] It can also be seen that the cavities 50, 52 each have a decreasing channel cross section around the axis X. Figure 4 As can be seen in FIG, these cavities 50, 52 have an axial dimension that decreases between 0° and 270° and then decreases again until the annular element is closed (i.e. over the rest of the circumference), so as to enable the supply pressure to be properly distributed in the orifice 58. If this were not the case, most of the fluid would pass through the orifice 50 opposite the supply duct 46.

[0099] According to the invention, the system 40 comprises at least one fluid channel 62 extending along the axis X and opening radially inwardly into the recess 44 of the outer ring 22 b.

[0100] In the first embodiment, the system 40 comprises a single fluid channel 62 having an annular shape around the axis X.

[0101] In the example shown, the channel 62 is located between the two cavities 50 , 52 and is empty.

[0102] exist Figure 16 In the variant shown, this channel 62 is filled with a honeycomb or porous structure 64 , for example of the lattice or lattice type.

[0103] The channel 62 is delimited radially outwardly by an annular base 62 a intended to face the outer ring 22 b of the bearing 22 .

[0104] Advantageously, the axial cross-section of the bottom 62a is convexly curved, as shown. This allows the cross-section of the fluid passage around the ring 22b to be locally reduced and accelerates its contact with the ring 22b, thereby optimizing the cooling of the ring 22b. This also makes it possible to limit areas of fuel stagnation within the passage.

[0105] The inner periphery of the passage 62 is closed by the outer ring 22 b of the bearing 22 .

[0106] Plane H is also channel 62 ( Figure 5 )'s symmetry plane.

[0107] exist Figure 2 、 Figure 3 and Figure 5 In FIG, the arrows show the flow of cooling fluid (preferably fuel) in the circuit 28. The fluid flows axially through the outer ring 22b and contacts the outer ring 22b, particularly in the channel 62. Figure 16 In the variation shown, the cooling of the ring 22 b by conduction is added to the cooling achieved by convection when the structure 64 contacts the ring 22 b within the recess 44. In this structure 64, the fluid path can be tortuous on a very small scale, but the general orientation of the fluid path remains parallel to the axis X.

[0108] Now refer to Figures 6 to 11 , which shows another embodiment of the present invention.

[0109] As in the previous embodiment, the guide and cooling device 24 comprises a rolling bearing 22 , a lubrication circuit for the bearing (circuit not shown), an annular housing 42 and a circuit 28 for cooling the bearing outer ring 22 b.

[0110] The following description focuses on Figures 6 to 11 The technical differences between the embodiment shown and the previously described embodiments are such that other features of these embodiments are the same or similar.

[0111] The circuit 28 comprises a single supply duct 46. This duct 46 has an elongated shape along the axis and comprises longitudinal ends connected to and opening into a cavity 50. Figure 4 As shown, the cross section of the pipe 46 is, for example, substantially rectangular.

[0112] A supply lumen 50 is disposed around the system 40. The lumen 50 may have a generally rectangular shape in axial cross-section.

[0113] It can be seen that the passage cross section of the cavity 50 decreases around the axis X. Figures 9 to 11 The radial dimension of the cavity 50 is shown, which decreases between 0° and 270° and then decreases again until the annular element is closed.

[0114] The circuit 28 comprises two discharge chambers 52 a , 52 b situated on either side of the cooling system 40 .

[0115] Each of the cavities 52a, 52b may have a generally triangular shape in axial cross section, thus having a fluid passage cross section that varies along the axis X.

[0116] It can also be seen that the cavities 52a, 52b each have a decreasing passage cross section around the axis X. Figures 9 to 11 It is shown that the axial dimension of these cavities 52a, 52b decreases between 0° and 270° and then decreases again until the annular element is closed.

[0117] As can be seen from the accompanying drawings (particularly FIG. 58 ), the cavities 52 a, 52 b may be symmetrical relative to a plane H perpendicular to the axis X and passing between the cavities 52 a, 52 b ( Figure 8 ).

[0118] The circuit 28 comprises two exhaust ducts 48a, 48b. The ducts 48a, 48b are similar to the ducts 46, 48 described above. The duct 48a has an elongated shape along the axis and comprises longitudinal ends connected to and opening into the cavity 52a. Figure 9 As shown, the cross section of the pipe 48a is, for example, substantially rectangular.

[0119] The duct 48b has an elongated shape along the axis and includes a longitudinal end portion that is angled and connected to the cavity 52b and opens into the cavity 52b. Figure 9 As shown, the cross section of the pipe 48b is, for example, substantially rectangular.

[0120] The figures also show that the ducts 46, 48a, 48b can be arranged one above the other and thus intersect the same plane passing through the axis X ( Figure 8 ).

[0121] The cavity 50 is connected to the cavity 52a via first channels 62a distributed around the axis X. The cavity 50 is connected to the cavity 52b via second channels 62b distributed around the axis X. The channels 62a are inserted between the channels 62b.

[0122] The number of channels 62 a is, for example, greater than 30. For example, the number of channels 62 b is, for example, greater than 30.

[0123] In particular, Figure 9 Each of the channels 62a, 62b is shown to be generally L-shaped and includes a first branch having a primarily axial orientation, the first branch extending from the first branch to the cavity 52a or 52b, and a second branch having a primarily radial orientation, the second branch extending outwardly from the first branch to the cavity 50.

[0124] Each of the channels 62 a , 62 b includes a radially inner end portion closed by the outer ring 22 b of the bearing 22 .

[0125] exist Figures 6 to 8 In FIG, the arrows show the flow of cooling fluid (preferably fuel) in circuit 28. The fluid circulates axially over and in contact with outer ring 22b, in particular in the first axial branches of channels 62a, 62b. The flow of fluid in channels 62a, 62b is advantageously opposite.

[0126] Now refer to Figures 12 to 15 , which shows another embodiment of the present invention.

[0127] This embodiment differs from the previous one substantially in that cavity 50 is connected to cavities 52a, 52b by all channels 62'. These channels 62' are distributed around axis X and each channel 62' is, for example, substantially T-shaped.

[0128] Each channel 62 ′ comprises a first branch with a predominantly axial orientation extending between and respectively opening into the cavities 52 a , 52 b and a second branch with a predominantly radial orientation extending from the middle of the first branch outwards to the cavity 50 .

[0129] The number of channels 62 ′ is greater than 30, for example.

[0130] exist Figure 12 and Figure 15 In FIG, the arrows show the flow of cooling fluid (preferably fuel) in the circuit 28. The fluid flows axially on and in contact with the outer ring 22b, in particular in the first axial branch of the channel 62'. Figure 15 Some fluid from cavity 50 is shown flowing in a first direction along axis X from cavity 50 to cavity 52a, and some fluid from cavity 50 flows in an opposite second direction along axis X from cavity 50 to cavity 52b.

[0131] 17a to 17c show a particular way of designing the supply chamber 50 and the discharge chambers 52, 52a, 52b. Each of these chambers may comprise or form at least one volute extending around the axis X.

[0132] In the case of FIG17 a , the chambers 50 , 52 , 52 a, 52 b comprise a single volute extending substantially 360° around the axis X. The volute has a passage cross section that varies around the axis X, being at a maximum at the connection of the volute to the respective duct 46 , 48 , 48 a, 48 b and being at a minimum at the circumferential end of the volute opposite the duct.

[0133] A volute of the type shown in Figure 17a can be Figure 9 、 Figure 10 、 Figure 11 and Figure 14 Seen in.

[0134] In the case of FIG. 17 b , the chambers 50 , 52 , 52 a , 52 b comprise four volutes evenly distributed around the axis X, each volute having an angular extent of approximately 90° around the axis X. The passage cross-section of each volute is greatest at its center, where it connects to the corresponding duct 46 , 48 , 48 a , 48 b , and is smallest at its circumferential ends. The volutes are connected to one another via their circumferential ends.

[0135] In the case of FIG17c , the chambers 50, 52, 52a, 52b comprise a single volute extending substantially 360° around the axis. The volute has a maximum passage cross section at its center, which is connected to the corresponding duct 46, 48, 48a, 48b, and a minimum passage cross section at its circumferential ends. The circumferential ends of the volute are connected to one another.

[0136] Figures 18a and 18b show two configurations for connecting conduits 46, 48, 48a, 48b to cavities 50, 52, 52a, 52b, respectively, in a device according to the present invention. In Figure 18a, the conduits 46, 48, 48a, 48b are completely straight and open axially into the cavities 50, 52, 52a, 52b. In Figure 18b, the conduits 46, 48, 48a, 48b have curved ends and open circumferentially into the cavities 50, 52, 52a, 52b.

[0137] Given the complexity of the housing 22 and the cooling circuit 28 that it partially contains, the housing 22 may be produced by additive manufacturing.

Claims

1. A device (28) for guiding a shaft (20) about an axis (X) and cooling a bearing of a gas generator, said device comprising: a rolling bearing (22) centered on the axis (X) and comprising an inner ring (22a), an outer ring (22b) and rolling elements (22c) arranged between these rings (22a, 22b), - a lubrication circuit (26) for lubricating the rolling bearing (22), an annular housing (42) extending around the bearing (22) and comprising an inner recess (44) for mounting the outer ring (22b), the housing (42) comprising a wall thickness (E) measured radially relative to the axis (X), and a cooling circuit (28) for cooling the outer ring (22b) of the bearing (22), said cooling circuit being independent of the lubrication circuit (26), Characterized in that the cooling circuit (28) comprises: at least one cooling fluid supply duct (46) and at least one cooling fluid discharge duct (48, 48a, 48b), the at least one cooling fluid supply duct and the at least one cooling fluid discharge duct being formed in the wall thickness (E) of the housing (42), at least one annular fluid supply chamber (50) extending around the axis (X) and formed in the wall thickness (E) of the housing (42), the annular chamber (50) being connected to the at least one supply duct (46), at least one annular fluid discharge chamber (52, 52a, 52b) extending around the axis (X) and formed in the wall thickness (E) of the housing (42), the annular chamber (52, 52a, 52b) being connected to the at least one discharge duct (48, 48a, 48b), and - an annular system (40) for cooling the outer ring (22b), the annular system being connected to the supply and discharge chambers (50, 52, 52a, 52b), respectively, the system (40) comprising at least one fluid channel (62, 62a, 62b, 62') extending along the axis (X) and opening inwards with a radial component into the recess (44) of the outer ring (22b).

2. The device (28) according to claim 1, wherein The system (40) includes a single fluid channel (62) having an annular shape about the axis (X).

3. The device (28) according to claim 2, wherein The single channel (62) is empty.

4. The device (28) according to claim 2, wherein The single channel (62) is filled with a honeycomb structure (64).

5. The device (28) according to any one of claims 2 to 4, wherein The single passage (62) is connected to the supply chamber (50) through a first series of apertures (58) formed in the housing (42) and to the discharge chamber (52) through a second series of apertures (60) formed in the housing (42).

6. The device (28) according to any one of claims 2 to 4, wherein The single channel (62) comprises an annular bottom 62a) facing the outer ring (22b) and having a convex curved shape in axial cross section.

7. The device (28) according to any one of the preceding claims, wherein The supply chamber and the discharge chamber (50, 52) are symmetrical with respect to a plane (H) perpendicular to the axis (X).

8. The device (28) according to claim 1, wherein The system (40) includes a plurality of fluid channels (62a, 62b, 62') distributed around the axis (X).

9. The device (28) according to claim 8, wherein The supply lumen (50) is a single supply lumen extending around the fluid passages (62a, 62b, 62').

10. The device (28) according to claim 8 or 9, wherein The fluid passage (62a, 62b, 62') is arranged between the first discharge chamber (52a) and the second discharge chamber (52b).

11. The device (28) according to claims 9 and 10 taken together, wherein The supply chamber (50) is connected to the first discharge chamber and the second discharge chamber (52a, 52b) through all of the fluid passages (62').

12. The device (28) according to claims 9 and 10 taken together, wherein The supply chamber (50) is connected to the first discharge chamber (52a) through a first fluid passage (62a), and is connected to the second discharge chamber (52b) through a second fluid passage (62b) interposed between the first fluid passages (62a).

13. The device (28) according to any one of claims 10 to 12, wherein The first and second discharge chambers (52a, 52b) are symmetrical with respect to a plane (H) perpendicular to the axis (X).

14. The device (28) according to any one of the preceding claims, wherein Each of the supply and discharge chambers (52a, 52b) forms or comprises one or more volutes around the axis (X).

15. A gas generator, such as a turbine or an auxiliary power unit, comprising at least one device according to any one of the preceding claims.

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