Accessory gearbox provided with an assembly of a shut-off cover and a holding system, and aircraft engine provided with such an accessory gearbox

Abstract

The present invention relates to an accessory gearbox (3) for an aircraft engine, comprising a casing (5) and an assembly (9) of a shut-off cover (11) and of a holding system (13), the shut-off cover (11) closing off an access hole and comprising a sleeve (15) that is slidable in the access hole, a shaft (17) mounted in the sleeve (15), a drive input that is couplable to a rotary drive tool (27), and a drive output (29) that is decoupled from the manual control in a first position and is couplable to the manual control in a second position, the holding system (13) being able to assume a coupling configuration only when the sleeve (15) is in the second position and being able to assume a decoupling configuration during decoupling of the rotary drive tool (27) and the drive input. The invention also relates to an aircraft engine.

Description

[0001] DESCRIPTION

[0002] TITLE: Accessory housing with a sealing cover and retaining system, and aircraft engine with such an accessory housing

[0003] FIELD OF INVENTION

[0004] The present invention relates to an aircraft engine accessory housing comprising an assembly of a sealing cover and a retaining system, and to an aircraft engine comprising such an accessory housing.

[0005] STATE OF THE ART

[0006] It is known to produce an accessory gearbox for an aircraft engine, which is a gear box typically located on the periphery of the engine and connected to the engine's high-pressure side by a shaft. Such an accessory gearbox is commonly referred to by its acronym AGB, for "Accessory Gear Box." This type of accessory gearbox incorporates a mechanism consisting of gears with parallel axes that mesh with each other. The accessory gearbox is generally driven mechanically from a drive shaft, specifically the high-pressure shaft of the aircraft engine, which is a turbomachine such as a turbojet or turboprop. Thus, during the aircraft engine's operation, the gears are driven by an input shaft that is itself connected via a drive train to a drive shaft of the aircraft engine.

[0007] This accessory housing drives various components, such as pumps and electric generators, and has access to a manual control connected to the internal drive train of the accessory housing by a pinion. Generally, one of the pinions is not used to drive any accessory equipment. This pinion is primarily used for manually rotating the engine shaft during aircraft engine inspection and overhaul operations. The accessory housing therefore includes a hole, opening, or passage providing access to a shaft carrying this pinion, which typically has an additional drive square housing to allow manual control of the pinion from the outside via a drive mechanism. Document FR 3 108 660 A1 discloses an actuator forming a drive mechanism, intended to be permanently held in the opening.Therefore, it is not possible to visually inspect the manual control. Alternatively, the opening is sealed with a blanking cover when the motor is not being serviced. During maintenance operations, after dismantling and removing or reversing the blanking cover, the manual control can be rotated manually with a hand crank or with a motorized tool that engages the control via the drive square. Maintenance operations include endoscopy and borescope repair, also known as boroblending. Boroblending and endoscopy are tasks that must be completed quickly, typically within 2 to 3 hours, as the motor needs time to cool down beforehand.

[0008] By rotating the manual control, the drive train connected to the engine's high-pressure housing can be rotated, allowing for engine endoscopy during maintenance operations. Conversely, when the engine is running, the internal drive train of the accessory gearbox rotates in line with the rotation of the high-pressure shaft within the engine's high-pressure housing. The manual control can also be used to completely lock the drive train, for example, to allow nuts to be tightened on the high-pressure shaft of an aircraft engine, which may be a twin-spool, twin-scroll turbomachine.

[0009] Document FR 3 105 997 A1 discloses an example of an accessory housing, which has access to a gear train comprising a manual control with a drive square machined at the end of a gear shaft. The shaft extends to an access opening, with an interposed bearing and possibly a dynamic seal. The assembly is closed by a blanking cover.

[0010] However, in certain engine configurations, numerous components or service lines pass through the access area of ​​the blanking plate that blocks access to the accessory gearbox gears, such as oil lines. Therefore, removing the blanking plate's mounting screws requires disconnecting some of these oil lines to allow sufficient clearance for unscrewing and then rescrewing the mounting screws during maintenance.Therefore, an operator performing maintenance must carry out numerous steps, such as: disconnecting oil lines, unscrewing the sealing cover screws, removing the sealing cover, installing a drive tool for the manual control of the accessory gearbox pinion, performing the maintenance, removing the drive tool, reinstalling the sealing cover, re-tightening the sealing cover screws, and reconnecting the oil lines. Furthermore, it is possible that, due to an oversight, the sealing cover may not be reinstalled or may be incorrectly screwed in at the end of the maintenance operations, and that upon starting the engine, oil normally present in the accessory gearbox may be expelled through the access opening.US document 2015 / 0233463 A1 discloses a plug that, in the event of incorrect reassembly, allows for the rapid detection of an oil leak through the access opening.

[0011] DESCRIPTION OF THE INVENTION

[0012] The present invention aims to overcome all or part of the disadvantages mentioned above.

[0013] The invention aims in particular to provide a sealing cover enabling a maintenance operation to be carried out by manual control of a pinion in a simple and quick manner, while avoiding the risk of forgetting or incorrectly mounting the sealing cover at the end of the maintenance operation.

[0014] According to a first aspect, the invention provides an aircraft engine accessory housing. The accessory housing is notable in that it comprises a casing with an access hole allowing access to a manual control of a pinion housed within the casing, and an assembly of a sealing cover and a retaining system, the sealing cover closing the access hole and comprising:

[0015] - a sleeve designed to slide into the access hole relative to the housing and parallel to an axis between a first position and a second position,

[0016] - a shaft mounted pivotally in the sleeve, the shaft being adapted to be driven in rotation about the axis, the shaft comprising: at an outer end, a drive input adapted to be coupled to a rotating drive tool, and at an inner end, a drive output adapted to be decoupled from the manual control in the first position and adapted to be coupled to the manual control in the second position, the retaining system being adapted to assume a coupling configuration only when the sleeve is in the second position, and in the coupling configuration, the retaining system axially retains the sleeve relative to the housing, and the retaining system being adapted to assume a decoupling configuration upon decoupling of the rotating drive tool and the drive input, and in the decoupling configuration,The retaining system releases the sleeve's sliding motion towards the first position. This provides an accessory housing equipped with a mechanism that allows for quick and easy maintenance via manual pinion control, eliminating the risk of forgetting or incorrectly installing the sealing cover at the end of the maintenance operation. Because the sealing cover is not removed, there is no need to dismantle any components or utilities in the access area that would obstruct access to the gear mechanism. Furthermore, because the sleeve,

[0017] The shaft, mounted pivoting within the sleeve, slides between two positions: a first position for normal operation and a second position for maintenance. This eliminates the risk of forgetting to close the cover. Furthermore, the shaft is disengaged during normal operation of the pinion, particularly the AGB, to prevent it from being driven outside of maintenance procedures. Finally, the coupling in the second position simplifies maintenance by an operator, as they only need to rotate the drive tool and do not need to axially support it to achieve rotation.

[0018] In this description, "specific to" means and can be replaced interchangeably by "configured for" or "intended for".

[0019] The accessory housing according to the invention is advantageously and optionally supplemented by the following features, taken alone or in any of their technically possible combinations:

[0020] - The first position is an operating position.

[0021] - The second position is a maintenance position.

[0022] The assembly includes an elastic return element, which returns the sleeve from the second position to the first position. This ensures that the sleeve is disengaged during normal operation, after maintenance.

[0023] - The sealing cover incorporates a spring return element, which returns the sleeve from the second position to the first position. This ensures that the sleeve is disengaged during normal operation, after maintenance.

[0024] - The elastic return element is designed to be compressed between the sleeve and the housing.

[0025] - The elastic return element is interposed between the housing and the sleeve. This direct interposition simplifies the design. - The elastic return element bears against opposing transverse faces of the housing and the sleeve. This allows for a simple manufacturing process.

[0026] - The sleeve has a first shoulder on which the elastic return element rests. Thus, the support of the elastic return element on the sleeve is achieved in a particularly simple manner.

[0027] - The elastic return element is a compression spring. Thus, the elastic return element is made in a particularly simple and safe way.

[0028] - The sleeve has an external groove housing a radially positioned O-ring seal between the sleeve and the housing. This ensures a simple seal for the housing.

[0029] - A bearing, preferably a plain bearing, is interposed radially between the sleeve and the shaft. This facilitates the rotation of the shaft relative to the sleeve while maintaining the sealing of the housing.

[0030] The holding system is designed to assume a decoupling configuration when an axial separation force of the sealing cover relative to the housing, applied to the sealing cover along its axis and directed from the second position to the first position, exceeds a predetermined threshold. Thus, at the end of the maintenance operation, it is sufficient to apply a force exceeding the predetermined threshold to decouple the shaft of the sealing cover from the manual pinion control; such decoupling is then carried out in a particularly simple manner.

[0031] The retaining system comprises at least one finger carried by the sleeve, the finger or fingers having at their free end: either a retaining ball in the second position to be reversibly engaged in a notch in the housing, or a permanent magnet to interact with a magnetic element carried by the housing such that, in the second position, the permanent magnet is in contact with the magnetic element. Thus, the retaining system is implemented in a particularly simple manner, and the coupling and decoupling processes are also simplified.

[0032] - The magnetic element carried by the housing is formed by the housing itself, by a ring of ferromagnetic material, or by a ring of a permanent magnet. This results in a particularly simple magnetic element. - The retaining system consists of two diametrically opposed fingers. This facilitates holding the device in the second position.

[0033] The retaining system comprises at least one pivotally mounted tab on the rotating drive tool. One free end of the tab has a retaining rib extending radially inwards. This retaining rib is designed to engage successively axially, parallel to the axis, and then tangentially around the axis, in a groove in the housing. This groove extends parallel to the axis in an axial portion of the groove, and then around the axis in a tangential portion of the groove. In this second position, when the rotating drive tool is coupled to the drive input, the retaining rib is held axially in the tangential portion of the groove. This prevents any unintentional disengagement during maintenance. The axial force transmitted by the rotating drive tool compresses the elastic element.Next, a limited angular rotation, for example a quarter turn, is applied to the rotary drive tool to engage the retaining system's tab in the tangential portion of the housing groove. The tab's retaining rib is then held in position by the rotary drive tool, which in turn holds the sleeve in the second position. The rotary drive tool can then be used to rotate the pinion in both directions.

[0034] - The groove is an L-shaped or J-shaped groove.

[0035] - The tangential part of the groove ends with an axial notch designed to receive the rib. Thus, the rotating drive tool can be rotated in both directions without the risk of ejection.

[0036] - A rotational drive of the drive input by the rotational drive tool causes a rotational drive of the manual control by the drive output only in the second position among the first and second positions.

[0037] - The shaft has a first shoulder designed to be in butt against the casing in the first position of the sleeve.

[0038] - The drive input has a female or male square drive, preferably a female square drive. This makes the drive input compatible with the respective square drive of a drive tool such as a manual wrench or a power tool, i.e., a male or female square drive. The female square drive is preferred because of its reduced mass. - The drive output has a male or female square drive, preferably a male square drive. This makes the drive output compatible with the respective square drive of the pinion, i.e., a female or male square drive.

[0039] - The sealing cover is suitable for oil-tight sealing of the access hole.

[0040] - The sleeve is designed to be butted against the casing in the second position.

[0041] - The sleeve, the shaft and the access hole are coaxial.

[0042] - The drive inlet is located externally to the housing.

[0043] - The drive output is oriented towards the inside of the crankcase.

[0044] - The drive output is located inside the housing.

[0045] - The sleeve is cylindrical.

[0046] - The bearing is in axial contact against a second shoulder of the shaft.

[0047] - The bearing has a shoulder forming an internal axial stop interposed between the sleeve and the shaft.

[0048] - The shaft has a groove receiving a circlip, which forms an external axial stop interposed between the sleeve and the shaft.

[0049] - The rotation drive tool is a manual ratchet wrench with a male or female drive square, preferably male with a retaining ball, more preferably male with a retaining ball conforming to ISO 1174-1:2011.

[0050] - The rotation drive tool is a reversible ratchet hand wrench, suitable for rotating the drive input in both directions.

[0051] According to a second aspect, the invention also proposes an aircraft engine, remarkable in that it comprises a high-pressure body and an accessory housing as previously described, the high-pressure body being mechanically coupled to the accessory housing.

[0052] DESCRIPTION OF THE FIGURES Other features, purposes and advantages of the invention will become apparent from the detailed description below, which is purely illustrative and not limiting, and which should be read in conjunction with the accompanying drawings, given by way of non-limiting examples and on which:

[0053] - Figure 1 is a schematic top view of an aircraft equipped with an aircraft engine according to the invention;

[0054] - Figure 2 is a schematic perspective view according to a first variant of the realization of an assembly and a housing of an accessory box and a rotating drive tool;

[0055] - Figure 3 is a schematic perspective top view in longitudinal section of the assembly and the casing shown in Figure 2;

[0056] - Figure 4 is a schematic perspective view of a detail of the casing shown in Figure 2;

[0057] - Figure 5 is a schematic perspective view of a detail of the assembly shown in Figure 2;

[0058] - Figure 6 is a schematic perspective view according to a second variant of the embodiment of an assembly and a housing of an accessory box and a rotating drive tool;

[0059] - Figure 7 is a schematic perspective view according to a third variant of the embodiment of an assembly and a housing of an accessory housing and a rotating drive tool.

[0060] Throughout the figures, similar elements are designated by identical references.

[0061] DETAILED DESCRIPTION OF THE INVENTION

[0062] Figure 1 schematically represents an aircraft 100 equipped with at least one aircraft engine 1, in the example shown, with two aircraft engines 1.

[0063] The aircraft engine 1 includes in particular a high-pressure body and an accessory housing 3, the high-pressure body being mechanically coupled to the accessory housing 3, which is partially shown in Figure 2.

[0064] Advantageously, aircraft engine 1 is a turbomachine, such as a turbojet or turboprop.

[0065] As shown in Figures 2 and 3, the accessory housing 3 includes a cover 5 with an access hole 7 for a manual control of a pinion. Thus, the access hole 7 allows access to the manual control of the pinion, not shown, which is housed within the cover 5. It should be noted that the cover 5 is only partially shown to improve the readability of these figures.

[0066] Thus, the casing 5 is a casing 5 of an accessory housing 3, preferably a casing 5 of an accessory housing 3 of an aircraft engine 1.

[0067] Advantageously, the crankcase 5 is made of steel.

[0068] Accessory case 3 also includes a set 9 of a shutter cover 11 and a retaining system 13.

[0069] The access hole 7 is sealed by the sealing cover 11. Thus, the sealing cover 11 is suitable for sealing the access hole 7 of the housing 5. Preferably, the sealing cover 11 is suitable for oil-tight sealing of the access hole 7.

[0070] The sealing cover 11 includes a sleeve 15 and a shaft 17.

[0071] Advantageously, sleeve 15 is made of steel.

[0072] Preferably, shaft 17 is made of stainless steel.

[0073] The sleeve 15 is designed to slide in the access hole 7 relative to the housing 5 and parallel to an axis X between a first position, notably represented in Figure 3, and a second position, notably represented in Figure 2.

[0074] Advantageously, the first position is an operating position.

[0075] Advantageously, the second position is a maintenance position.

[0076] Preferably, sleeve 15 is cylindrical.

[0077] Advantageously, the sleeve 15, the shaft 17 and the access hole 7 are coaxial, in other words X-axis coaxial.

[0078] Preferably, the shaft 17 has a first shoulder 18 suitable for abutting the housing 5 in the first position of the sleeve 15.

[0079] Advantageously, the sleeve 15 has an external groove 19 housing a sealing O-ring 21 arranged radially between the sleeve 15 and the housing 5. The shaft 17 is pivotally mounted in the sleeve 15. The shaft 17 is thus able to be driven in rotation around the X axis.

[0080] The shaft 17 includes, at an outer end, a drive input 25 suitable for coupling to a rotating drive tool 27. By "outer end", it is necessary to understand the end of the shaft 17 oriented towards the outside of the housing 5.

[0081] Advantageously, the rotation drive tool 27 is a manual ratchet wrench with a male or female drive square, preferably male with a retaining ball, more preferably male with a retaining ball conforming to ISO 1174-1:2011.

[0082] Preferably, the rotation drive tool 27 is a reversible ratchet hand wrench, suitable for rotating the drive input 25 in both directions.

[0083] The shaft 17 includes, at an inner end, a drive output 29 adapted to be decoupled from the manual control in the first position and adapted to be coupled to the manual control in the second position. By "inner end," we mean the end of the shaft 17 oriented towards the inside of the housing 5.

[0084] Advantageously, the drive inlet 25 is located externally to the housing 5.

[0085] Advantageously, the drive input 25 has a female or male drive square, preferably a female drive square, as shown in Figure 3.

[0086] Preferably, the sleeve 15 is designed to be butted against the housing 5 in the second position.

[0087] Advantageously, a rotational drive of the drive input 25 by the rotational drive tool 27 causes a rotational drive of the manual control by the drive output 29 only in the second position among the first and second positions.

[0088] Preferably, the drive output 29 is oriented towards the inside of the housing 5.

[0089] Advantageously, the drive output 29 is located inside the housing 5.

[0090] Advantageously, the drive output 29 has a male or female drive square, preferably a male drive square. The retaining system 13 is designed to assume a coupling configuration only when the sleeve 15 is in the second position. More precisely, in the coupling configuration, the retaining system 13 axially holds the sleeve 15 relative to the housing 5.

[0091] The retaining system 13 is designed to take a decoupling configuration when the rotating drive tool 27 and the drive input 25 are decoupled. More specifically, in the decoupling configuration, the retaining system 13 releases the sliding of the sleeve 15 towards the first position.

[0092] Advantageously, the assembly 9, preferably the sealing cover 11, includes an elastic return element 31, which is adapted to return the sleeve 15 from the second position to the first position. Thus, the elastic return element 31 returns the sleeve 15 from the second position to the first position.

[0093] Preferably, the elastic return element 31 is suitable for being compressed between the sleeve 15 and the housing 5. Thus, the elastic return element 31 is compressed between the sleeve 15 and the housing 5.

[0094] Advantageously, the elastic return element 31 is interposed between the housing 5 and the sleeve 15.

[0095] Preferably, the elastic return element 31 is a compression spring.

[0096] Advantageously, the elastic return element 31 is made of spring steel.

[0097] Preferably, the elastic return element 31 bears against opposite transverse faces of the housing 5 and the sleeve 15.

[0098] Advantageously, the sleeve 15 has a first shoulder 33 on which the elastic return element 31 rests.

[0099] Advantageously, a bearing 35, preferably a plain bearing, is interposed radially between the sleeve 15 and the shaft 17.

[0100] Preferably, bearing 35 is a plain brass bearing.

[0101] Preferably, the bearing 35 is axially butted against a second shoulder 37 of the shaft 17. Advantageously, the bearing 35 has a shoulder 39 forming an internal axial stop interposed between the sleeve 15 and the shaft 17.

[0102] Preferably, the shaft 17 has a groove receiving an elastic ring or circlip 41, which forms an external axial stop interposed between the sleeve 15 and the shaft 17.

[0103] Preferably, circlip 41 is metallic.

[0104] Advantageously, according to a first embodiment shown in Figure 2, Figure 3, Figure 4 and Figure 5, and according to a second embodiment shown in Figure 6, the retaining system 13 is able to take a decoupling configuration when an axial separation force of the sealing cover 11 relative to the housing 5, applied to the sealing cover 11 along the X axis and oriented from the second position to the first position, is greater than a predetermined threshold.

[0105] Preferably, the retaining system 13 includes at least one finger 43 carried by the sleeve 15. Advantageously, the retaining system 13 includes two fingers 43, preferably two diametrically opposed fingers 43, in particular with respect to the X axis.

[0106] Advantageously, and according to the first embodiment, the finger 43 or each finger 43 carries at its free end a retaining ball 45 suitable in the second position to be reversibly engaged in a notch 47 of the housing 5. The notch 47 is in particular shown in Figure 4, and the retaining ball 45 is in particular shown in Figure 5.

[0107] Preferably, in the second position, the free end of the finger 43 or of each finger 43 is engaged in an axial groove 48 in which the notch 47 is made.

[0108] Advantageously, the free end of the finger 43 or of each finger 43 has a protrusion 43a complementary to the axial groove 48.

[0109] Advantageously, the retaining ball 45 is made in a conventional manner, similar to the retaining ball of the rotating drive tool 27. Thus, to hold the sleeve 15 in the second position, the retaining ball 45 can be pushed out of the finger 43 into the notch 47 by an internal spring. This internal spring compresses when the retaining system 13 assumes its decoupling configuration, allowing the retaining ball 45 to press against the internal spring in the finger 43 and slide out of the notch 47, thereby enabling axial movement of the sleeve 15 from the second position to the first position.According to the second embodiment shown in Figure 6, the retaining system 13 differs from the retaining system 13 according to the first embodiment in that the finger 43 or each finger 43 carries at its free end, a permanent magnet 49 adapted to interact with a magnetic element 51 carried by the housing 5 such that, in the second position, the permanent magnet 49 is in contact with the magnetic element 51. In other words, the permanent magnet 49 according to the second embodiment replaces the retaining ball 45 according to the first embodiment.

[0110] In figure 6, sleeve 15 is in the first position.

[0111] Advantageously, the magnetic element 51 carried by the housing 5 is formed by the housing 5 itself, by a ring of ferromagnetic material or by a ring of a permanent magnet.

[0112] Figure 7 represents a third variant embodiment of an assembly 9, a rotating drive tool 27 and a housing 5.

[0113] In figure 7, sleeve 15 is in the first position.

[0114] According to this third embodiment, the retaining system 13 differs from the retaining system 13 according to the first and second embodiments in that the retaining system 13 comprises at least one tab 53 pivotally mounted on the rotating drive tool 27, a free end of the tab 53 having a retaining rib extending radially inwards, the retaining rib being adapted to be engaged successively only axially parallel to the X-axis and then tangentially around the X-axis in a groove 55 of the housing 5 extending parallel to the X-axis in an axial portion of the groove 55 and then around the X-axis in a tangential portion of the groove 55. Thus, in the second position of the sleeve 15 and when the rotating drive tool 27 is coupled to the drive input 25, the retaining rib is retained axially in the tangential portion of the groove 55.

[0115] Advantageously, groove 55 is an L-shaped or J-shaped groove.

[0116] Preferably, the tangential part of the groove 55 ends with an axial notch 57 suitable for receiving the rib.

[0117] To perform a maintenance operation using the assembly 9, the aircraft engine 1 is stopped, the rotating drive tool 27 is engaged in the drive input 25, the elastic return element 31 is compressed axially along the X axis by means of the circlip 41 against the sleeve 15, the sleeve 15 then sliding from the first position into the second position, the drive output 29 being engaged in the manual control of the pinion.

[0118] The sleeve 15 then occupies the second position, and the retaining system 13 takes its coupling configuration which holds the sleeve 15 in the second position until the end of the maintenance operation.

[0119] Once maintenance is complete, the operator removes the rotating drive tool 27, causing the retaining system 13 to move into its disengaged position. Since the retaining system 13 no longer holds the sleeve 15 in the second position, the sleeve 15 returns to the first position through the action of the elastic return element 31 until the shaft 17 is fully against the housing 5. In the first position of the sleeve 15, the drive output 29 is disengaged from the manual pinion control.

[0120] Aircraft engine 1 can then be restarted safely, particularly because the sealing cover 11 has not been removed. Furthermore, the shaft 17 does not rotate during the operation of aircraft engine 1, especially in flight.

[0121] The invention is not limited to the embodiments and variants shown, and other embodiments will be obvious to those skilled in the art. In particular, it is possible to combine the embodiments and variants with each other.

Claims

DEMANDS 1. Aircraft engine accessory housing (3) (1), characterized in that it comprises a casing (5) having an access hole (7) allowing access to a manual control of a pinion housed in the casing (5), and an assembly (9) of a sealing cover (11) and a retaining system (13), the sealing cover (11) sealing the access hole (7) and comprising: - a sleeve (15) designed to slide in the access hole (7) relative to the housing (5) and parallel to an axis X between a first position and a second position, - a shaft (17) pivotally mounted in the sleeve (15), the shaft (17) being adapted to be driven in rotation about the axis, the shaft (17) comprising: at an outer end, a drive input (25) adapted to be coupled to a rotating drive tool (27), and at an inner end, a drive output (29) adapted to be decoupled from the manual control in the first position and adapted to be coupled to the manual control in the second position, the retaining system (13) being adapted to assume a coupled configuration only when the sleeve (15) is in the second position, and in the coupled configuration, the retaining system (13) axially retains the sleeve (15) relative to the housing (5), and the retaining system (13) being adapted to assume a decoupled configuration upon decoupling of the rotating drive tool (27) and the drive input (25), and in the decoupled configuration,The retaining system (13) releases the sliding of the sleeve (15) towards the first position.

2. Accessory housing (3) according to claim 1, in which the sealing cover (11) carries an elastic return element (31), which is suitable for returning the sleeve (15) from the second position to the first position.

3. Accessory housing (3) according to claim 1 or 2, in which the sleeve (15) has an external groove (19) housing a sealing O-ring (21) arranged radially between the sleeve (15) and the housing (5).

4. Accessory housing (3) according to any one of claims 1 to 3, in which a plain bearing (35) is interposed radially between the sleeve (15) and the shaft (17).

5. Accessory housing (3) according to any one of claims 1 to 4, wherein the retaining system (13) is adapted to assume a decoupling configuration when an axial separation force of the sealing cover (11) relative to the housing (5), applied to the the sealing cover (11) along the X axis and oriented from the second position to the first position, is greater than a predetermined threshold.

6. Accessory housing (3) according to any one of claims 1 to 5, wherein the retaining system (13) comprises at least one finger (43) carried by the sleeve (15), the finger (43) or each finger (43) having at its free end: - a retaining ball (45) in the second position to be reversibly engaged in a notch (47) of the housing (5), or - a permanent magnet (49) suitable for interacting with a magnetic element (51) carried by the housing (5) such that, in the second position, the permanent magnet (49) is in contact with the magnetic element (51).

7. Accessory housing (3) according to claim 6, in which the retaining system (13) comprises two diametrically opposed fingers (43).

8. Accessory housing (3) according to any one of claims 1 to 5, in which the retaining system (13) comprises at least one lug (53) pivotally mounted on the rotating drive tool (27), a free end of the lug (53) having a retaining rib extending radially inwards, the retaining rib being adapted to be engaged successively only axially parallel to the X axis and then tangentially around the X axis in a groove (55) of the housing (5) extending parallel to the X axis in an axial part of the groove (55) and then around the X axis in a tangential part of the groove (55), such that in the second position and when the rotating drive tool (27) is coupled to the drive input (25), the retaining rib is retained axially in the tangential part of the groove (55).

9. Accessory housing (3) according to any one of claims 1 to 8, wherein the drive input (25) has a female or male drive square.

10. Aircraft engine (1), characterized in that it comprises a high-pressure body and an accessory housing (3) according to any one of claims 1 to 9, the high-pressure body being mechanically coupled to the accessory housing (3).

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