Assembly for turbomachine accessory housing

Abstract

This disclosure relates to an accessory housing of a turbomachine, the accessory housing comprising an assembly (1) including: - a tubular shaft (2) intended to be driven in rotation about a longitudinal axis (X), - a pinion (3) rotationally coupled to the tubular shaft (2), and - at least two annular air / oil mixture separation elements (4) arranged around the tubular shaft (2) and rotationally fixed to the tubular shaft (2), each annular element (4) comprising an annular body (41) housing an annular filter (42), each annular body (41) comprising an air / oil mixture inlet (43), an oil outlet (44) opening radially outside the annular body (41), and a filtered air outlet (45) opening radially inside the tubular shaft (2). Abstract figure: Figure 3

Description

Title of the invention: Assembly for turbomachine accessory housing technical field

[0001] This disclosure relates to an accessory housing assembly for a turbomachine, and more particularly to an assembly capable of ensuring the separation of an air / oil mixture. Previous technique

[0002] An accessory gearbox is a component used to support and mechanically drive other equipment, called accessories, such as electric generators, oil or fuel pumps, or others, necessary for the operation of the turbomachine or the aircraft on which the turbomachine is mounted. To provide this drive, the required power is taken from a main shaft of the turbomachine, generally by means of a radial drive shaft meshed with the main shaft, and this power is then mechanically transmitted to the accessory gearbox. The accessory gearbox typically comprises a fixed housing containing gears that distribute power to the various accessories.

[0003] The accessory gearbox can also be combined with an air / oil mixture separation device, also known as an oil separator. To do this, air is drawn directly from the turbomachine's air stream. This air then passes through the turbomachine and is subsequently vented to the outside of the turbomachine to limit the pressure buildup in other areas of the turbomachine. This air, having passed through various areas of the turbomachine, is laden with oil used for cooling and lubricating the bearings and gears of the rotating assemblies. To avoid the release of oil-laden air, mitigate the environmental impact of turbomachines, reduce oil consumption, and limit the need for oil reservoir refilling, it is important to provide devices that separate the oil from the air before venting the air to the outside of the turbomachine.

[0004] It is known to implement the air / oil mixture separation device in an additional accessory outside the accessory housing. [Fig. 1] represents such a device comprising an air / oil mixture inlet 11, a housing 12 delimiting a first chamber 13 for receiving the air / oil mixture and a second chamber 14 for receiving the oil extracted from the air / oil mixture, a filter element 15, an oil outlet 16 and a shaft 17 having a channel 18 for discharging the filtered air, the filter element 15 being integral with the shaft 17.

[0005] The air-oil mixture is drawn into the crankcase through inlet 11, then passes through filter element 15 where the oil is separated from the air and extracted radially outwards by centrifugal force, before flowing into the second chamber 14 where it is discharged at the bottom through outlet 16. The filtered air, having passed through filter element 15, is directed to channel 18 of shaft 17 before being discharged to the outside. The separation of the mixture by filter element 15 can, in particular, be achieved by rotating cross-linked foams or a porous material.

[0006] This arrangement, although allowing for the treatment of a large air / oil mixture flow rate, is bulky.

[0007] However, some recent engines require the accessory drive unit to be installed in a more confined space within the turbomachine. In this case, the compactness of the accessory drive unit is more important.

[0008] With the aim of improving the compactness of air / oil mixture separation devices, one solution provided is to integrate the separation device within the accessory housing, as is known from document FR 3 064 305 in the name of the Applicant.

[0009] Figure 2 illustrates such a device arranged and driven by a mechanical power take-off at the accessory gearbox. The device comprises an annular air / oil mixture inlet 11, a filter element 15, an oil outlet 16, a shaft 17 rotating about its longitudinal axis X, and a toothed pinion 19 mounted on the shaft. The toothed pinion meshes with another pinion in the accessory gearbox to drive the shaft 17 in rotation. The tubular shaft 17 forms an internal channel 18 for the discharge of the filtered air. The terms axial and radial are defined with respect to the longitudinal axis X.

[0010] The air-oil mixture is drawn into the crankcase through inlet 11, then passes through filter element 15 where the oil is separated from the air and extracted radially outwards by centrifugal force, before being discharged. The filtered air, having passed through filter element 15, is directed to channel 18 of shaft 17 before being discharged to the outside. The separation of the mixture by filter element 15 can similarly be achieved by rotating cross-linked foams or a porous material.

[0011] However, such integration of the separation device into the accessory housing implies a reduction in the diameter of the filter elements to be compatible with the external diameter of a toothed pinion. This results in higher pressure losses than in the external filtration configuration.

[0012] There is currently a need to recover as much energy as possible in order to improve the efficiency of the turbomachine.

[0013] The invention aims to provide a solution to this need in a simple, inexpensive and reliable way. Summary

[0014] This disclosure improves the situation.

[0015] An assembly for an accessory housing of a turbomachine is proposed, comprising a tubular shaft intended to be driven in rotation about a longitudinal axis, a pinion rotationally coupled to the tubular shaft, and at least two, in particular two, annular air / oil mixture separation elements arranged around the tubular shaft and rotationally fixed to the tubular shaft. Each annular element comprises an annular body housing an annular filter. Each annular body comprises at least one, in particular one or more, air / oil mixture inlets, at least one, in particular one or more, oil outlets opening radially outside the annular body, and at least one, in particular one or more, filtered air outlets opening radially inside the tubular shaft.

[0016] A tubular shaft is understood to mean, in particular, that the shaft is hollow and includes an internal tubular conduit coaxial with the axis of the tubular shaft. Said at least one filtered air outlet then opens radially into the internal tubular conduit.

[0017] In particular, at least two annular organs are understood to mean that the annular filters of each of said at least two annular organs are fluidly separated from each other.

[0018] The terms longitudinal and radial are defined with respect to the longitudinal axis of the rotating tubular shaft.

[0019] The annular air / oil mixture separation element is configured in particular so that an air / oil mixture enters each annular element through said at least one corresponding air / oil mixture inlet, and is then driven into rotation in the annular element so that the oil contained in the air / oil mixture is radially centrifuged out of the annular element through said at least one corresponding oil outlet and the filtered air enters the tubular shaft.

[0020] More specifically, the assembly may include air circulation means to ensure air circulation between at least one air / oil mixture inlet of the annular body and the interior of the operating tubular shaft. This air circulation may result from a pressure difference between an external pressure on the annular component, corresponding in particular to a pressure inside the accessory housing, and a pressure inside the tubular shaft, which may correspond to atmospheric pressure.

[0021] By implementing at least two distinct annular air / oil mixture separation devices, the present disclosure makes it possible to offer at least two different paths for filtering the air / oil mixture. This configuration thus allows to increase the air passage cross-section and consequently to reduce the pressure losses of the assembly, and more generally of the turbomachine.

[0022] Furthermore, the present disclosure makes it possible to increase the compactness of the means used for separating an air / oil mixture by means of the compact integration of said at least two annular air / oil mixture separation elements into the accessory housing.

[0023] The features described in the following paragraphs may optionally be implemented independently of each other or in combination with each other:

[0024] Advantageously, the pinion is arranged longitudinally between at least two of said at least two annular elements. This configuration allows for a balanced mounting of the annular elements on the tubular shaft on both sides of the pinion.

[0025] At least two of said at least two annular organs are advantageously positioned on the same side of the pinion along the longitudinal axis.

[0026] The pinion can form a bottom wall of the annular body of at least one of said at least two annular elements, preferably two annular elements, the two annular elements being positioned respectively on either side of the pinion along the longitudinal axis. This configuration makes it possible to increase the compactness and integration of the assembly, and to reduce the mass of the assembly.

[0027] Advantageously, at least one of said at least two annular components is structurally distinct from the other annular component(s) of said at least two annular components. Creating structurally distinct units of annular components thus allows for the modularization of the air / oil mixture separation means, thereby facilitating their manufacture and assembly.

[0028] Advantageously, the annular bodies of a pair of two annular components of said at least two annular components are structurally linked so as to form a single double annular body, that is, formed in one piece. More specifically, said at least one air / oil mixture inlet of the annular body of one annular component of said pair is provided at a first longitudinal end of said same double annular body. Said at least one air / oil mixture inlet of the annular body of the other annular component of said pair is provided at a second longitudinal end of said same double annular body opposite said first longitudinal end. In other words, the pair of two annular components allows an air / oil mixture to be received at the inlet from two sides longitudinally opposed to each other.This configuration advantageously improves the overall compactness by using a single annular body housing two annular filters.

[0029] The assembly can be configured as follows: a. the assembly comprises only two annular bodies structurally distinct from each other and positioned longitudinally respectively on either side of the pinion; b. the assembly comprises only a pair of two annular organs whose annular bodies are structurally linked so as to form a single double annular body; c. the assembly comprises only a first pair of two annular organs whose annular bodies are structurally linked so as to form a single double annular body and a second pair of two annular organs whose annular bodies are structurally linked so as to form a single double annular body, the first pair of two annular organs and said second pair of two annular organs being positioned longitudinally respectively on either side of the pinion; d. The assembly comprises only a pair of two annular bodies whose annular bodies are structurally linked so as to form a single double annular body and a third annular body structurally distinct from said pair of two annular bodies, said pair of two annular bodies and said third annular body being positioned longitudinally respectively on either side of the pinion.

[0030] The tubular shaft may advantageously include an axial stop against which the annular body of one of said at least two annular members is mounted. The assembly may include a locking element that holds the corresponding annular body against the axial stop.

[0031] The annular filter may comprise a plurality of filter elements and the annular body may form a plurality of circumferentially side-by-side housings separated by radial walls of the annular body, each housing of the plurality of housings housing a filter element of the plurality of filter elements.

[0032] The annular filter can in particular be made of a cross-linked foam or of a porous material.

[0033] According to another aspect, an accessory housing for a turbomachine is proposed, comprising an assembly as previously described.

[0034] The assembly as previously described is notably mounted inside the accessory housing.

[0035] Advantageously, the accessory housing comprises a casing containing a plurality of power take-offs capable of being driven by a turbomachine shaft and capable of rotating at least one accessory piece of equipment. Each power take-off includes, in particular, a shaft and at least one pinion rotationally coupled to the tree. The assembly is notably mounted to one of the power outlets of the accessory box.

[0036] The accessory box may comprise a plurality of assemblies as previously described, each of the assemblies being mounted to a separate power outlet of the accessory box.

[0037] According to another aspect, a turbomachine is proposed comprising the accessory housing as previously described. Brief description of the drawings

[0038] Other features, details and advantages will become apparent from reading the detailed description below and from analyzing the accompanying drawings, in which: Fig. 1

[0039] [Fig.l] schematically illustrates a cross-sectional view of an example of a separation device according to the prior art. Fig. 2

[0040] [Fig.2] schematically illustrates a cross-sectional view of another example of a device of separation according to the prior art. Fig. 3

[0041] [Fig.3] schematically illustrates a cross-sectional view of an assembly according to one embodiment. Fig. 4

[0042] [Fig.4] schematically illustrates a cross-sectional view of an assembly according to a mode of realization. Fig. 5

[0043] [Fig.5] schematically illustrates a cross-sectional view of an assembly according to one embodiment. Fig. 6

[0044] [Fig.6] schematically illustrates a cross-sectional view of an assembly according to one embodiment. Fig. 7

[0045] [Fig.7] schematically illustrates two views (figures 7A and 7B) of a bladed wheel of a set according to a mode of embodiment. Description of the implementation methods

[0046] Figures 3, 4, 5 and 6 represent an assembly 1 for an accessory housing of a turbomachine. The assembly is mounted inside the accessory housing.

[0047] The accessory housing conventionally comprises a casing housing a plurality of power take-offs capable of being driven by a turbomachine shaft and capable of drive at least one accessory component in rotation. Each power take-off (PTO) includes, in particular, a shaft and at least one gear rotationally coupled to the shaft. The assembly described in this disclosure is mounted, in particular, to one of the power take-offs of the accessory box. The accessory box may include multiple assemblies, each of which is mounted to a separate power take-off of the accessory box.

[0048] The assembly 1 comprises a tubular shaft 2, i.e. hollow, intended to be driven in rotation about a longitudinal axis X and a pinion 3 coupled in rotation to the tubular shaft 2. It is understood in particular by tubular shaft that the shaft is hollow, i.e. that it has an internal tubular conduit 21 coaxial with the axis of the tubular shaft 2.

[0049] The terms longitudinal and radial are defined with respect to the longitudinal axis X of the rotating tubular shaft.

[0050] More particularly, the pinion 3 comprises an annular disc 31 carrying at its radially external end a toothing intended to be coupled in rotation with a corresponding toothing of another pinion.

[0051] With reference to Figures 3 and 4, assembly 1 comprises at least two annular air / oil mixture separators 4 arranged around the tubular shaft 2 and rotationally fixed to the tubular shaft 2. The annular air / oil mixture separator is also referred to as an oil separator. Assembly 1 may, for example, comprise two, three, or four annular air / oil mixture separators 4.

[0052] Each annular organ 4 comprises an annular body 41, 41' housing an annular filter 42. It is understood in particular by at least two annular organs that the annular filters of each of said at least two annular organs are fluidly separated from each other.

[0053] Each annular body 41 includes in particular a radially extending bottom wall and a radially external annular wall connected at a longitudinal end to a radially external end of the bottom wall.

[0054] The annular filter 42 may comprise a plurality of filter elements, and the annular body may form a plurality of circumferentially adjacent housings separated by radial walls of the annular body, each housing in the plurality of housings containing a filter element from the plurality of filter elements. The annular filter 42 may, in particular, be made of a cross-linked foam or a porous material.

[0055] Each annular body 41 comprises at least one, in particular one or more, air / oil mixture inlets 43, each of which may be annular, and at least one, in particular one or more, oil outlets 44, each of which may be annular. opening radially outside the annular body 41 and at least one, in particular one or more, filtered air outlets 45 opening radially inside the tubular shaft 2.

[0056] Said at least one air / oil mixture inlet 43 opens in particular longitudinally opposite the annular filter 42.

[0057] Said at least one air / oil mixture inlet may, in particular, be provided at a longitudinal end of the annular body 4L. Said at least one air / oil mixture inlet may, in particular, comprise an air / oil mixture inlet orifice extending annularly at a longitudinal end of the annular body 41 opposite the bottom wall of the annular body. Alternatively, said at least one air / oil mixture inlet may, in particular, comprise a plurality of air / oil mixture inlet orifices distributed circumferentially at a longitudinal end of the annular body 4L.

[0058] Said at least one oil outlet includes in particular a plurality of oil outlet orifices distributed circumferentially on the radially external wall of the annular body 4L The oil outlet orifices may in particular form one or more annular rows of oil outlet orifices, each of the annular rows of oil outlet orifices being spaced longitudinally from each other.

[0059] Said at least one filtered air outlet is in particular arranged, at least partially, opposite one or more orifices 22 of the tubular shaft opening into the interior of the tubular shaft, in particular into the tubular conduit 21. Said at least one filtered air outlet may in particular form a filtered air outlet orifice extending annularially opposite said one or more orifices 22 of the tubular shaft.

[0060] In particular, the annular air / oil mixture separation element is configured so that an air / oil mixture enters each annular element through said at least one corresponding air / oil mixture inlet, and is then driven into rotation in the annular element so that the oil contained in the air / oil mixture is radially centrifuged out of the annular element through said at least one corresponding oil outlet and the filtered air enters the tubular shaft.

[0061] More specifically, the assembly may include means for circulating air so that air circulates between said at least one air / oil mixture inlet of the annular body and the inside of the operating tubular shaft. This air circulation may result from a pressure difference between a pressure external to the annular component, corresponding in particular to a pressure inside the accessory housing, and a pressure inside the tubular shaft, which may correspond to atmospheric pressure.

[0062] By implementing at least two distinct annular air / oil mixture separation devices, the present disclosure provides at least two different paths for filtering the air / oil mixture. This configuration thus increases the air passage area and consequently reduces the pressure losses of the assembly, and more generally of the turbomachine.

[0063] Furthermore, the present disclosure makes it possible to increase the compactness of the means used for separating an air / oil mixture thanks to the compact integration of said at least two annular air / oil mixture separation elements into the accessory housing.

[0064] With reference to [Fig.3], the pinion 3 can be arranged longitudinally between at least two of said at least two annular members 4. This configuration allows for a balanced mounting of the annular members on the tubular shaft on either side of the pinion 3.

[0065] At least one of said at least two annular components 4 may be structurally distinct from the other annular component(s) of said at least two annular components. In other words, the annular component 4 forms a unit that is structurally distinct from the other annular components. Creating structurally distinct units of annular components in this way allows for the modularization of the air / oil mixture separation means, thereby facilitating their manufacture and assembly.

[0066] With reference to assembly 1 illustrated in [Fig.4], at least two of said at least two annular members can be positioned on the same side of pinion 3 along the longitudinal axis X.

[0067] The annular bodies 41 respectively of a pair of two annular organs 4 of said at least two annular organs can be structurally linked so as to form a single double annular body 41', as shown in [Fig.4].

[0068] More specifically, said at least one air / oil mixture inlet 43 of the annular body of one annular member of said couple is provided at a first longitudinal end 46a of said same double annular body 41'. Said at least one air / oil mixture inlet of the annular body of the other annular member of said couple is provided at a second longitudinal end 46b of said same double annular body opposite said first longitudinal end 46a.

[0069] In other words, the pair of two annular elements allows an air / oil mixture to be received at the inlet from two sides longitudinally opposed to each other. This configuration advantageously improves the overall compactness by using a single annular body housing two annular filters. Furthermore, this configuration simplifies assembly by reducing the number of components to be mounted.

[0070] In particular, the assembly can be configured so that: a. assembly 1 comprises only two annular organs 4 structurally distinct from each other and positioned longitudinally respectively on either side of the pinion 3 (as illustrated in [Fig.3]); b. assembly 1 comprises only a pair of two annular organs 4 whose annular bodies are structurally linked so as to form a single double annular body 41' (as illustrated in [Fig.4]); c. assembly 1 comprises only a first pair of two annular bodies whose annular bodies are structurally linked so as to form a single double annular body 41' and a second pair of two annular bodies whose annular bodies are structurally linked so as to form a single double annular body 41', the first pair of two annular bodies and said second pair of two annular bodies being positioned longitudinally respectively on either side of the pinion 3 (not illustrated); d. assembly 1 comprises only a pair of two annular bodies whose annular bodies are structurally linked so as to form a single double annular body 41' and a third annular body structurally distinct from said pair of two annular bodies, said pair of two annular bodies and said third annular body being positioned longitudinally respectively on either side of pinion 3 (not illustrated).

[0071] Any other arrangement of the assembly comprising several structurally distinct units of annular organs, several pairs of annular organs or a combination of structurally distinct units of annular organs and pairs of annular organs, is also conceivable.

[0072] In an example of an embodiment not shown, the pinion 3 can form the bottom wall of the annular body of at least one of said at least two annular elements 4, in particular of two annular elements positioned respectively on either side of the pinion 3 along the longitudinal axis. This configuration makes it possible to increase the compactness and integration of the assembly, and to reduce the mass of the assembly. The radial wall can thus be formed by the web of the pinion.

[0073] Furthermore, the tubular shaft 2 may advantageously include an axial stop 23, in particular an annular one, against which the annular body 41 of one of said at least two annular members is mounted. The assembly 1 may include a locking element 6 such as a nut / circlip which holds the corresponding annular body against the axial stop 23.

[0074] Furthermore, with reference to Figures 3, 4, 5 and 6, assembly 1 may include at least one, in particular one or more, bladed wheels 5, each being mounted inside the tubular shaft 2, more precisely in the tubular conduit 21, and which is coupled in rotation to the tubular shaft 2. In operation, one axis of the bladed wheel coincides in particular with the longitudinal axis X of the tubular shaft 2.

[0075] The bladed wheel is specifically configured to assist the circulation of filtered air inside the tubular shaft 2. The bladed wheel thus acts as a ventilation system.

[0076] By "assisting the circulation of filtered air" it is understood that the bladed wheel is configured: - to draw filtered air from the annular element towards the inside of the tubular shaft, when the bladed wheel is arranged downstream of the annular element with respect to the direction of airflow inside the tubular shaft; or - to expel the filtered air from the annular organ towards the inside of the tubular shaft, when the bladed wheel is arranged upstream of the annular organ with respect to the direction of airflow inside the tubular shaft.

[0077] In other words, said at least one bladed impeller forces the air / oil mixture through the annular element for filtering the mixture. More precisely, the bladed impeller acts on the circulation of filtered air, for example, in addition to a pressure difference between an external pressure on the annular element, corresponding in particular to a pressure inside the accessory housing, and a pressure inside the tubular shaft, which may correspond to atmospheric pressure, as explained previously.

[0078] Such a bladed wheel therefore makes it possible to limit pressure losses and improve the performance of the turbomachine.

[0079] In particular, assembly 1 may include one bladed wheel, as illustrated in Figures 4, 5 and 6, two bladed wheels as illustrated in [Fig.3], or more than two bladed wheels (not illustrated).

[0080] The bladed wheel is preferably mounted on one side or the other of a median plane P of the annular member 4. This positioning of the bladed wheel, away from the median plane of the annular member, offers the advantage of being able to improve the impact of the rotation of the bladed wheel on the circulation of filtered air in the tubular shaft.

[0081] The bladed wheel can in particular be formed in one piece with the pinion 3 (not illustrated).

[0082] Figures 7A and 7B illustrate two views of an example of a bladed wheel 5.

[0083] Each bladed wheel includes, in particular, a hub 51 and blades 53 extending radially outwards from hub 51.

[0084] The hub 51 can in particular form a hub of the bladed wheel.

[0085] The blades are in particular regularly distributed around the axis of the bladed wheel.

[0086] Each of the blades 53 is preferably substantially inclined.

[0087] The blades 53 can be curved in shape, in particular along the longitudinal axis X.

[0088] Furthermore, each bladed wheel may include a radially external annular ferrule 52 arranged radially outside the hub 51. The radially external annular ferrule 52 is configured to be fixed against an internal surface 24 of the tubular shaft 2, for example by shrink fitting. The implementation of a radially external annular ferrule advantageously facilitates the mounting of the bladed wheel inside the tubular shaft.

[0089] Furthermore, a radially external surface 54 of the hub 51 preferably has a cylindrical shape, either convergent or divergent. Adapting the shape of the radially external surface of the hub advantageously allows influencing the flow of filtered air inside the tubular shaft by improving the aerodynamics of the bladed wheel.

[0090] Similarly, a radially internal surface 55 of the radially external annular ferrule 52 may advantageously have a cylindrical, convergent, or divergent shape. Adapting the shape of the radially internal surface of the radially external annular ferrule advantageously allows for influencing the flow of filtered air inside the tubular shaft by improving the aerodynamics of the bladed wheel.

[0091] Furthermore, with reference to [Fig.6], the assembly may advantageously include an air inlet 7 opening longitudinally into the inside of the tubular shaft 2, the air inlet 7 being arranged upstream of the pinion 3 along the longitudinal axis X.

Claims

Demands

1. Accessory housing of a turbomachine, the accessory housing comprising an assembly (1) including: - a tubular shaft (2) intended to be driven in rotation about a longitudinal axis (X), - a pinion (3) rotationally coupled to the tubular shaft (2), and - at least two annular air / oil mixture separation elements (4) arranged around the tubular shaft (2) and rotationally fixed to the tubular shaft (2), each annular element (4) comprising an annular body (41, 41') housing an annular filter (42), the annular filters of each of said at least two annular elements (4) being fluidly separated from each other, each annular body (41, 41') comprising an air / oil mixture inlet (43), an oil outlet (44) opening radially outside the annular body (41) and a filtered air outlet (45) opening radially into the inside of the tubular shaft (2).

2. Accessory housing according to claim 1, in which the pinion (3) is arranged longitudinally between the two annular members (4).

3. Accessory housing according to any one of the preceding claims, in which the two annular members (4) are positioned on the same side of the pinion (3) along the longitudinal axis (X).

4. Accessory housing according to any one of the preceding claims, wherein the pinion (3) forms a radial wall of the annular body (41, 41') of one of the two annular members (4), preferably of both annular members (4), the two annular members (4) being positioned respectively on either side of the pinion (3) along the longitudinal axis (X).

5. Accessory housing according to any one of the preceding claims, wherein one of the two annular members (4) is structurally distinct from the other of the two annular members (4).

6. Accessory housing according to any one of the preceding claims, wherein the annular bodies of the two annular members (4) are structurally linked so as to form a single double annular body (41'), the air / oil mixture inlet (43) of the annular body of one annular member (4) of said pair being provided at a first longitudinal end (46a) of said same annular body double (41'), the air / oil mixture inlet (43) of the annular body of the other annular body (4) of said couple being arranged at a second longitudinal end (46b) of said same double annular body (41') opposite said first longitudinal end (46a).

7. Accessory housing according to any one of the preceding claims, wherein the assembly is configured such that: a. the assembly (1) comprises only two annular members (4) structurally distinct from each other and positioned longitudinally respectively on either side of the pinion (3); b. the assembly (1) comprises only a pair of two annular members (4) whose annular bodies are structurally linked so as to form a single double annular body (41'); c.the assembly (1) comprises only a first pair of two annular bodies (4) whose annular bodies are structurally linked so as to form a single double annular body (41') and a second pair of two annular bodies (4) whose annular bodies are structurally linked so as to form a single double annular body (41'), the first pair of two annular bodies (4) and said second pair of two annular bodies (4) being positioned longitudinally respectively on either side of the pinion (3); d.the assembly (1) comprises only a pair of two annular organs (4) whose annular bodies are structurally linked so as to form a single double annular body (41') and a third annular organ (4) structurally distinct from said pair of two annular organs (4), said pair of two annular organs (4) and said third annular organ (4) being positioned longitudinally respectively on either side of the pinion (3).

8. Accessory housing according to any one of the preceding claims, wherein the tubular shaft (2) has an axial stop (23) against which the annular body (41, 41') of one of the two annular members (4) is mounted, the assembly (1) comprising a locking element (6) which holds the corresponding annular body (41, 41') against the axial stop (23).

9. Accessory housing according to any one of the preceding claims, comprising a bladed wheel (5) mounted inside the tubular shaft (2) and rotationally coupled to the tubular shaft (2).

10. Turbomachine comprising an accessory housing according to one of the preceding claims.

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