Patent Publication Number: US-2022235672-A1

Title: Turbomachine output bearing support

Description:
TECHNICAL FIELD 
     The present presentation relates to a turbomachine output bearing support. 
     The term “turbomachine” designates all gas turbine units producing drive power, distinguished examples of which especially are turbojets providing thrust necessary for propulsion by reaction to the high-speed ejection of hot gases, and turboshafts in which the drive power is provided by the rotation of an engine shaft. For example, turboshafts are used as engines for helicopters, ships, trains, or also as industrial engines. Turboprops (turboshaft driving a helix) are also turboshafts used as aircraft engines. 
     The turbomachine output bearing is the latest bearing of the turbomachine considered in terms of gas flow inside the turbomachine, from upstream to downstream, carrying one or more rotor shafts of the turbomachine. 
     PRIOR ART 
     Known turbomachine bearing output supports are generally complex items comprising several parts machined separately and then joined together, especially by bolting. Such a manufacturing process is complex and costly. Also, assembly by bolting makes these known bearing supports relatively heavy pieces. There is therefore a need in this sense. 
     DISCLOSURE OF THE INVENTION 
     An embodiment relates to a turbomachine output bearing support extending according to an axial direction, said support being formed by one and the same piece and comprising an inner wall having an inner side and an outer side, an outer wall and a twist support. 
     Hereinbelow and unless expressed otherwise, “support” means “turbomachine output bearing support”. A twist is an element also known by the skilled person, which prevents oil leaks from a bearing. 
     The axial direction is defined by a geometric axis of the support, for example an axis of symmetry of revolution. A radial direction is a direction perpendicular to the axial direction. The azimuthal or circumferential direction corresponds to the direction describing a ring around the axial direction. The three axial, radial and azimuthal directions correspond respectively to the directions defined by the side, the radius and the angle in a cylindrical coordinates system. Also, unless expressed otherwise, the adjectives “internal/inner” and “external/outer” are used in reference to a radial direction such that the internal part (i.e. radially internal) of an element is closer to the axis defining the axial direction than the external part (i.e. radially external) of the same element. 
     It is understood that the outer and inner walls are annular and that the outer wall is arranged to the outer side of the inner wall. 
     Forming the support by one and the same piece, for example by additive manufacturing, can eliminate assembly elements of supports known from the prior art. Also, forming the support by one and the same piece can do away with some parts of supports known from the prior art, and can integrate them fully or partly with the inner wall and/or the outer wall and/or the twist support. This also avoids some complex machining necessary in supports known from the prior art. 
     In some embodiments, the inner wall comprises a first section having a first substantially frustoconical form (i.e. annular divergent form) extending according to the axial direction and having the inner side and the outer side, the first section having a first axial end provided with a first attachment flange and a second axial end, opposite according to the axial direction to the first axial end, provided with a bearing support section, the first section carrying on the inner side an inner section forming a second attachment flange. 
     “Substantially frustoconical” or “divergent annular form” means a regular frustoconical form (i.e. of a constant angle relative to the axial direction), an irregular frustoconical form (i.e. of a constant angle per section along the axial direction, different from one section to the other), a concave curved form (for example in the form of a bell) or convex (for example in the form of a trumpet bell), a combination of the above forms, or more generally any annular geometry connecting a first axial end having a first diameter to a second axial end having a second diameter larger than the first diameter. 
     In some embodiments, the twist support is carried by the inner wall on the outer side. 
     In other terms, the twist support extends from the external side of the inner wall. For example, the twist support is arranged between the inner wall and the outer wall. 
     In some embodiments, the outer wall has a second substantially frustoconical form (i.e. divergent annular form) extending according to the axial direction and having a third axial end attached to the inner wall on the outer side of the inner wall, and a fourth axial end, opposite the second axial end according to the axial direction, forming a collector ring. 
     In other terms, the outer wall extends from the external side of the inner wall. The inner wall and the outer wall are coaxial. The twist support can be coaxial with the inner wall and the outer wall. 
     The collector ring can be an annular section configured to collect/discharge pressurised fluid, for example gas, from the internal side of the outer wall. For example, a cavity is formed between the external wall and the twist support, the collector ring being configured to discharge pressurised fluid in this cavity. For example, the collector ring can form an annular chamber having one or more radial openings in fluidic communication with the interior of the support. 
     In some embodiments, the turbomachine output bearing support comprises at least one air exhaust duct extending from the external side of the outer wall and fluidically connecting the inner side of the inner wall and the collector ring. 
     The air exhaust duct can discharge gases collected in the collector ring to the inner side of the inner wall. For example, the exhaust duct can also extend over the outer side of the inner wall. For example, the outer wall and/or the inner wall form at least one section of the walls forming the air exhaust duct. 
     Compared to the supports of the prior art, such a duct especially dispenses with much bulkier and heavier additional walls and therefore significantly reduces the mass of the support. 
     In some embodiments, the turbomachine output bearing support comprises three air exhaust ducts uniformly distributed around the axial direction. 
     Such a configuration ensures uniform air discharge and uniformly distributes the mass over the circumference of the support. 
     In some embodiments, the at least one air exhaust duct has an air outlet opening arranged in the inner wall. 
     In some embodiments, the turbomachine output bearing support comprises an oil drainage duct. 
     Such a drainage duct collects the lubricating oil of the bearing which escapes from the oil circuit of the bearing. Such a drainage duct is distinct from an oil recovery duct of the oil circuit of the bearing. For example, the oil drainage duct can be configured to drain oil by gravity. For example, the bearing support can have a top and a base, the drainage duct being arranged to the side of the base of the support. For example, the drainage duct can define the low side of the support. 
     In some embodiments, the oil drainage duct extends on the outer side of the outer wall and has a first intake arranged in the collector ring, a second intake arranged in the outer wall and opening in a space formed between the twist support and the outer wall, and an output terminating to the inner side of the inner wall. 
     For example, the drainage duct can also extend over the outer side of the inner wall. For example, the outer wall and/or the inner wall form at least one section of the walls forming the drainage duct. Compared to supports of the prior art, such a duct especially dispenses with additional heavy and bulky walls and therefore significantly reduces the mass of the support. 
     An embodiment also relates to a manufacturing process of a turbomachine output bearing support according to any one of the embodiments described in the present presentation, comprising at least one additive manufacturing step. 
     As a reminder, additive manufacturing is a manufacturing process by addition of material, by stacking of successive layers. For example, the successive layers are formed by powder which is sintered selectively by laser. 
     Such a manufacturing process is particularly well-adapted to make complex pieces such as the turbomachine output bearing support forming the subject matter of the present presentation. This especially avoids some complex machining steps which are necessary in supports of the prior art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The aim of the present presentation and its advantages will become clearer from the following detailed description given hereinbelow of different embodiments given by way of non-limiting examples. This description makes reference to the pages of attached figures, in which: 
         FIG. 1  illustrates a turbomachine, 
         FIG. 2  illustrates the output bearing support of the turbomachine of  FIG. 1 , in perspective, 
         FIG. 3  illustrates the output bearing support of the turbomachine of  FIG. 1 , according to another view in perspective, 
         FIG. 4  illustrates the output bearing support of the turbomachine seen according to the sectional plane IV of  FIG. 3 , and 
         FIG. 5  illustrates the output bearing support of the turbomachine seen according to the plane V of  FIG. 4 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
       FIG. 1  illustrates a schematic view of a turbomachine  100 , in this example a twin-body turbojet, comprising a turbomachine output bearing support  10 . In this example, the turbomachine  100  comprises a casing  110  housing a low-pressure body  120 , a high-pressure body  140  and a combustion chamber  160 . The low-pressure body  120  comprises a low-pressure compressor  120 A and a low-pressure turbine  120 B coupled in rotation by a shaft  120 C. The high-pressure body  140  comprises a high-pressure compressor  140 A and a high-pressure turbine  140 B coupled in rotation by a shaft  140 C. The shaft  120 C is coaxial to the shaft  140 C, and extends through the shaft  140 C. The shafts  120 C and  140 C are mobile in rotation around the axis X of the turbomachine. 
     The turbomachine output bearing support  10  extends according to the axial direction X, and is coaxial with the shafts  120 C and  140 C. In this example, the support  10  supports the bearing of the shaft  120 C arranged to the side of the output S of the turbomachine  100 , the gas flowing inside the turbomachine  100  from upstream to downstream from the intake E to the output S according to the arrow shown in bold. 
     The turbomachine output bearing support  10  is described in more detail in reference to  FIGS. 2, 3, 4 and 5 . It is noted that only the support  10  is shown in these figures. In particular, the bearing and the twist which are carried by this support  10  are not shown. The support  10  extends according to the axial direction X, according to a radial direction R and a circumferential direction C. 
     The support  10  is formed by one and the same piece by additive manufacturing and comprises an inner wall  12 , an outer wall  14  and a twist support  16 . The inner wall  12  has an inner side CI and an outer side CE 
     The inner wall  12  comprises a first section  12 A having a first substantially frustoconical form extending according to the axial direction X and having the inner side CI and the outer side CE, the first section  12 A having a first axial end  12 A 1  provided with a first attachment flange  18  and a second axial end  12 A 2 , opposite according to the axial direction X to the first axial end  12 A 1 , provided with a bearing support section  20 , the first section  12 A carrying on the inner side CI an inner section  22  forming a second attachment flange. In this example, the inner section  22  comprises a sleeve  22 A extending according to the axial direction X and attached to the first section  12 A, on the inner side Cl. The sleeve  22 A carries a section forming an attachment flange  22 B. In this example, the diameter of the second flange  22  is less than the diameter of the first flange  18 . The second flange  22  is arranged retracted according to the axial direction X relative to the first flange  18 , inside the inner wall  12 . In this example, the sleeve  22 A has a third substantially frustoconical form of axis X (the second substantially frustoconical form being formed by the second wall described in more detail hereinbelow) and opposite inclination relative to the inclination of the first section  12 A. 
     In this example, the first section  12 A has on the inner side CI a cylindrical section  24  of axis X and section transverse to the circular axial direction. The cylindrical section  24  is arranged radially between the inner section  22  and the first flange  18 . The distal end of the section  24  is arranged retracted according to the axial direction X of the section forming the flange  22 B, inside the inner wall  12 . The section  24  is configured to attach an oil intake lid, for example by sintering. A sealing joint can also be arranged between said lid and the section  24 . 
     It is evident that the first section  12 A has through holes  23 A arranged radially between the bearing support section  20  and the inner section  22  and through holes  23 B arranged radially between the inner section  22  and the cylindrical section  24 . These holes  23 A and  23 B are uniformly distributed according to the circumferential direction C. These holes  23 A and  23 B form passages for flow of oil of the bearing not shown and carried by the bearing support  10 . 
     The twist support  16  is carried by the inner wall  12 , on the outer side CE. In this example, the twist support  16  has a sleeve  16 A extending according to the axial direction X and attached to the first section  12 A, on the outer side CE. The sleeve  16 A carries a section forming a twist support  16 B. In this example, the diameter of the section of twist support  16 B is less than the diameter of the bearing support section  20 . The section of twist support  16 B is arranged beyond the bearing support section  20  according to the axial direction X, on the external side of the inner wall  12 . In this example, the sleeve  16 A has a fourth substantially frustoconical form of axis X inclined to the same side relative to the axial direction as the first section  12 A. 
     The outer wall  14  has a second substantially frustoconical form extending according to the axial direction X and having a third axial end  14 A attached to the inner wall  12  on the outer side CE of the inner wall  12 , and a fourth axial end  14 B, opposite the second axial end  14 A according to the axial direction X, forming a collector ring  26 . The substantially frustoconical form of the outer wall  14  is inclined to the same side relative to the axial direction X as the first section  12 A. 
     In this example, the first, second, third and fourth substantially frustoconical forms are all different. According to a variant, some of these forms, or even all these forms, could be identical (for example all regular frustoconical, but of different sizes). 
     In this example, the collector ring  26  is an annular section forming an annular chamber having several radial openings  26 A oriented to the interior of the bearing support  10  and uniformly distributed according to the circumferential direction C. In this example, a cavity  30  is formed between the external wall  14  and the twist support  16 , the collector ring  26  being configured to discharge pressurised fluid, in this example gas, from this cavity  30 . 
     The collector ring  26  is connected fluidically to the internal side CI of the inner wall  12  via air exhaust ducts  32 . In this example, there are three air exhaust ducts  32  uniformly distributed around the axial direction X (i.e. the ducts  32  are spaced at 120° according to the circumferential direction C). Each duct  32  has an air outlet opening  32 A arranged in the inner wall  12 . As is seen in  FIG. 4 , in this example the outer wall  14  forms a section of the walls of each air exhaust duct  32 . 
     The support  10  in this example has three tappings  34 ,  36  and  38  for fluidic connecting of the support  10  to an oil feed circuit of the bearing. In this example, the tappings  34 ,  36  and  38  are arranged on the inner side CI of the inner wall  12 . 
     The tapping  34  is an oil feed tapping connected to an oil feed conduit  33  partly visible in  FIG. 2 , and terminating in the bearing support section  20  via the orifice  33 A. In this example the conduit  33  is arranged in the thickness of the inner wall  12 , and more particularly in this example of the first section  12 A. The support  10  being formed by one and the same piece by manufacturing additive, the formation of this conduit  33  is facilitated and avoids complex machining necessary in the supports known from the prior art. 
     The tapping  36  is an oil recovery tapping connected to a collector  37  arranged between the outer wall  14 , the inner wall  12  and the twist support  16 . In this example, the collector  37  has a wall  37 A extending radially between the twist support  16 , in this example the sleeve  16 A, the outer wall  14 , and the inner wall  12 . The collector  37  has an opening  37 B arranged in the twist support  16 , in this example the sleeve  16 A Also, a through hole  23 A is arranged vertically to the opening  37 B, viewed according to the radial direction R. 
     The tapping  38  is an oil drainage tapping connected to an oil drainage duct  40 . The oil drainage duct  40  extends on the external side of the outer wall  14  and has a first intake  42  arranged in the collector ring  26 , a second intake  44  arranged in the outer wall  14  and opening in the space  30  formed between the twist support  16  and the outer wall  14 . The tapping  38  forms the output of the conduit  40  which terminates to the internal side Cl of the inner wall  12 . As is seen in  FIG. 4 , the outer wall  14  and the inner wall  12  each form a section of the wall of the drainage duct  40 . 
     In this example, the second intake  44  comprises two through holes  44 A arranged in the outer wall  14 , on either side according to the circumferential direction C of the collector  37 , and adjacent to the collector  37  (see  FIG. 5 ). 
     In this example, the drainage duct  40  defines the base B of the support  10 , the top H being diametrically opposite. In this way, the support  10  is configured to be mounted inside the turbomachine  100 , with the top H and the base B considered accordingly (i.e. the top above the base and inversely) according to the direction of gravity G, during normal operation of the turbomachine  100 . The drainage of the oil occurs accordingly by gravity. 
     In this example, the drainage duct  40  is arranged diametrically opposite an air exhaust duct  32 , and equidistant according to the circumferential direction C of the two other air exhaust ducts  32 . 
     For example, with air circulating via the holes  23 B which can possibly contain oil, this oil is drained by the drainage duct  40  via the second intake  44 . 
     Even though the present invention has been described in reference to specific embodiments, it is evident that modifications and changes can be made to these examples without departing from the general scope of the invention such as defined by the claims. In particular, individual characteristics of the different embodiments as illustrated/mentioned can be combined into additional embodiments. Consequently, the description and the drawings must be considered in an illustrative rather than restrictive sense. 
     It is also evident that all characteristics described in reference to a process can be transposed, singly or in combination, to a device, and inversely all the characteristics described in reference to a device can be transposed, singly or in combination, to a process.