LINEAR HYDRAULIC ACTUATOR FOR AN AIRCRAFT TURBOMACHINE

Abstract

Linear hydraulic actuator (100), in particular for an aircraft turbomachine (1), comprising: - a tubular inner body (102) comprising a first external cylindrical surface (102a), - a tubular outer body (106) comprising a piston (108) movable in axial translation on the first surface (102a), the inner body (102) comprising a first cylindrical wall (110), and the outer body (106) comprising a second cylindrical wall (140) which surrounds the first cylindrical wall (110), one of these first and second walls (110, 140) comprising axial grooves (112) and the other of these first and second walls (140, 110) carrying rollers (142) which are housed in these grooves (112) and which are capable of cooperating by rolling with these grooves (112) to guide the translation of the outer body (106) on the inner body (102) while blocking the rotation of the external body (106) with respect to the internal body (102). Figure for abstract: Figure 3

Description

Title of the invention: LINEAR HYDRAULIC ACTUATOR FOR AN AIRCRAFT TURBOMACHINE Field of invention

[0001] The present invention relates to a linear hydraulic actuator, in particular for an aircraft turbomachine. It also relates to a turbomachine module comprising a variable-pitch blade propeller and an actuator of the aforementioned type. Technical background

[0002] Turbomachines generally comprise a ducted fan or an unducted propeller equipped with variable pitch moving blades. A ducted fan equipped with variable pitch or variable pitch blades makes it possible to adjust the pitch or orientation of the blades according to the flight parameters so as to optimize the operation of the fan. This configuration makes it possible to optimize the module in which such a fan is integrated. As a reminder, the pitch angle of a blade corresponds to the angle, in a longitudinal plane perpendicular to the axis of rotation of the blade, between the chord of the blade and the plane of rotation of the fan.The variable-pitch blades can occupy a so-called reverse thrust position (known as "reverse") in which they generate counter-thrust to help slow down the aircraft and a feathering position in which, in the event of failure or breakdown, they limit their aerodynamic drag. The fan blades are rotated by a drive shaft. Such an example of a fan with variable-pitch blades is described in patent application FR-A1-3 087 233.

[0003] Turbomachines equipped with unducted propellers are known by the English term "open rotor" or "unducted fan". In this category of turbomachine, there are those which have two unducted and counter-rotating propellers (known by the English acronym UDF for "Unducted Fan") or those having a single unducted propeller and a rectifier comprising several stator blades (known by the English acronym USF for "Unducted Single Fan"). The propeller or propellers forming the propulsion part can be placed at the rear of the gas generator (or engine) so as to be of the pusher type or at the front of the gas generator so as to be of the tractor type. These turbomachines are turboprops which are distinguished from turbojets by the use of a propeller outside the nacelle (unducted) instead of an internal fan presented above.This allows the bypass ratio to be increased significantly without being penalized by the mass of the casings or nacelles intended to surround the propeller or fan blades. Variable timing allows. for the same purpose of braking the aircraft or limiting aerodynamic drag in the event of failure.

[0004] Currently, whether it is ducted fans or unducted propellers with variable pitch blades, the pitch change system comprises a control means which is connected on the one hand to a fan shaft which is typically driven by the engine shaft via a speed reducer and on the other hand to a connecting mechanism coupled to the variable pitch blades. The control means, located in a rotating frame of reference of the turbomachine, generally comprises a linear hydraulic actuator which comprises a movable body which, when moved, acts on the position of the blades of the variable pitch blades. The actuator is supplied by a fluid such as oil, the supply source of which is arranged in a fixed frame of reference of the turbomachine. A fluid transfer device of the OTB type (acronym for OU Transfer Bearing) allows the passage from the fixed frame of reference to the rotating frame comprising the actuator.

[0005] The kinematics of actuation of the blades uses several elements in addition to the actuator and for example an eccentric, connecting rods, a synchronization ring, etc. This kinematics of change of pitch of the propeller causes a translation and a rotational movement of the actuator. This rotational movement induced by the kinematics must be stopped by an anti-rotation part.

[0006] One anti-rotation solution could be to install anti-rotation rods to connect the synchronizing ring gear to a propeller stator. However, this solution would not be ideal because these rods would be positioned at a large radius relative to the propeller rotation axis, which would obstruct access to the blade roots and would not facilitate assembly and access in this area.

[0007] The present invention provides a solution to this problem, which is simple, effective and economical. Summary of the invention

[0008] The invention relates to a linear hydraulic actuator, in particular for an aircraft turbomachine, this actuator having a general shape elongated along an axis and comprising:

[0009] - a tubular inner body which extends along the axis and which includes a housing internal body capable of receiving a fluid transfer device from a fixed reference point to a rotating reference point, the internal body comprising a first external cylindrical surface,

[0010] - a tubular outer body which extends along the axis and around the inner body and which comprises a piston movable in axial translation on the first surface, this piston axially separating two annular fluid cavities which are capable of being supplied with fluid to ensure axial translation of the piston and the external body on the internal body,

[0011] characterized in that the inner body comprises a first cylindrical wall, and the outer body comprises a second cylindrical wall which surrounds the first cylindrical wall, one of these first and second walls comprising axial grooves and the other of these first and second walls carrying rolling rollers which are housed in these grooves and which are capable of cooperating by rolling with these grooves to guide the translation of the outer body on the inner body while blocking the rotation of the outer body with respect to the inner body.

[0012] The particularity of the actuator according to the invention is in particular that it integrates an anti-rotation system with rolling rollers. The use of several rolling rollers makes it possible to better distribute the anti-rotation force.

[0013] In the present invention, the term "roller" or "rolling roller" is used to mean an element making it possible to replace sliding friction with rolling friction. It is therefore understood that the rollers are capable of rolling in the grooves and in particular of rolling on longitudinal edges of these grooves. The or each roller may have a cylindrical, frustoconical or curved rolling surface (for example U-shaped or V-shaped). The number of rollers is preferably equal to the number of grooves and is, for example, between 2 and 10, preferably between 3 and 8, and is, for example, 4. The rollers, like the grooves, are preferably regularly distributed around the axis of the actuator.

[0014] The actuator may also comprise one or more of the following features, considered independently of one another or in combination with one another: • the internal body comprises first and second adjacent axial sections, the first axial section comprising said housing and said first surface, and the second axial section comprising said first wall. • the second section of the internal body comprises at its free end located on the side opposite the first section an annular row of blind holes which open radially inwards and are capable of receiving barrel nuts. • the first section of the internal body is of the double-skin type and comprises an internal skin defining said first surface, and an external skin defining a second internal cylindrical surface which surrounds the first surface, the first and second surfaces defining between them an annular space which receives said piston and which is separated in two by said piston to form said cavities. • the annular space is closed at a first axial end by an annular veil of the internal body which connects the internal and external skins, and at a second opposite axial end by an attached and fixed annular plug on the outer skin of the inner body. • the internal body comprises an annular fixing flange, preferably radially external, projecting from its external skin. • the internal body comprises first internal fluid conduits, ends of which open into said internal housing, and opposite ends of which open into one of the cavities, and second internal fluid conduits, ends of which open into said internal cavity, and opposite ends of which open into the other of the cavities. • the first and second conduits are formed in said skins, or even in said veil. • the internal body comprises third internal fluid conduits, ends of which open into said internal housing, and opposite ends of which open radially inwards. • the first and second sections of the internal body are formed from a single piece. • the external body comprises a tubular portion, one part of which forms said second wall and one longitudinal end of which forms said piston or is connected to said piston. • the tubular portion of the external body comprises an annular fixing flange, preferably radially external, at its longitudinal end opposite said piston. • the tubular portion of the external body is able to slide axially inside the cap. • the tubular portion of the external body is formed from a single piece.

[0015] The invention also relates to an assembly comprising an actuator as described above, and a device for transferring fluid from a fixed reference point to a rotating reference point. This device is mounted axially at least partly in the housing of the internal body and comprises, for example, two bodies, respectively stator and rotor. The stator body is engaged in the rotor body which is rotationally integral with the internal body of the actuator. A fluid such as oil is intended to supply the actuator via the transfer device, circulating from the stator body to the rotor body and then to the internal body of the actuator.

[0016] The invention also relates to a turbomachine module, comprising a propeller comprising a plurality of variable-pitch blades, and a system for changing the pitch of the propeller blades, this system comprising an actuator as described above.

[0017] The module may also comprise one or more of the following characteristics, considered independently of one another or in combination with one another: • the external body of the actuator is connected to the internal periphery of a flange annular whose external periphery is connected to the roots of the propeller blades; • the internal periphery of the flange comprises a flange for fixing to the flange of the external body; • a fluid transfer device is mounted axially inside said actuator housing; • a blade pitch locking system, for example of the pitchlock type, is mounted axially inside the second section of the internal body; • the locking system is capable of being supplied with fluid by said third pipes; • the rollers are of the needle bearing type; • each of the rollers has an external cylindrical guide surface capable of cooperating by rolling with longitudinal edges of the groove in which it is engaged; • the rollers each have a threaded part engaged in an orifice in the first wall or the second wall, and capable of receiving a fixing nut.

[0018] The invention further relates to an aircraft turbomachine comprising at least one turbomachine module according to any one of the preceding characteristics. Brief description of the figures

[0019] The invention will be better understood, and other aims, details, characteristics and advantages thereof will appear more clearly on reading the detailed explanatory description which follows, of embodiments of the invention given as purely illustrative and non-limiting examples, with reference to the appended schematic drawings in which:

[0020] [Fig-1] [Fig.l] is a schematic view, in axial and partial section of an example of a turbomachine with a ducted fan to which the invention applies;

[0021] [Fig.2] [Fig.2] schematically represents, in a partial axial section, an example of a turbomachine module with a propeller and a system for changing the pitch of the propeller blades;

[0022] [Fig.3] [Fig.3] is a schematic axial sectional view of a linear hydraulic actuator according to one embodiment of the invention;

[0023] [Fig.4] [Fig.4] is a schematic perspective view of the linear hydraulic actuator of [Fig.3];

[0024] [Fig.5a] [Fig.5a] is a schematic axial sectional view of an internal body of the linear hydraulic actuator of [Fig.3];

[0025] [Fig.5b] [Fig.5b] is another schematic axial sectional view of the internal body of the linear hydraulic actuator of [Fig.3];

[0026] [Fig.6] [Fig.6] is a schematic perspective view of the internal body of the linear hydraulic actuator of [Fig.3];

[0027] [Fig.7] [Fig.7] is a schematic axial sectional view of an external body of the linear hydraulic actuator of [Fig.3];

[0028] [Fig.8] [Fig.8] is a schematic axial sectional view of a plug of the linear hydraulic actuator of [Fig.3];

[0029] [Fig.9] [Fig.9] is a schematic perspective view of a roller of the linear hydraulic actuator of [Fig.3];

[0030] [Fig. 10] [Fig. 10] is a schematic sectional view of a roller of the linear hydraulic actuator of [Fig.3];

[0031] [Fig. 11] [Fig. 11] schematically represents, in a partial axial section, an example of a turbomachine module with a propeller and a system for changing the pitch of the propeller blades, this system comprising the actuator of [Fig.3]. Detailed description of the invention

[0032] [Fig.l] represents a turbomachine intended to be mounted on an aircraft. The aircraft comprises a fuselage and at least two wings extending on either side of the fuselage along the axis of the fuselage. At least one turbomachine is mounted for example under each wing. The turbomachine may be a turbojet, for example a turbomachine equipped with a ducted fan (turbofan) or a turboprop, for example a turbomachine equipped with an unducted propeller ("open rotor", "USF" for "Unducted Single Fan" or "UDF" for "Unducted Fan"). Of course, the invention applies to other types of turbomachine.

[0033] Generally speaking and in the remainder of the description, the term “blower” is used to designate either a blower or a propeller.

[0034] In the present invention, and generally, the terms "upstream", "downstream", "axial" and "axially" are defined with respect to the circulation of gases in the turbomachine and here along the longitudinal axis X (and even from left to right in [Fig. 1]). Similarly, the terms "radial", "radially", "internal", "internal", "external" and "external" are defined with respect to a radial axis Z perpendicular to the longitudinal axis X and with respect to the distance from the longitudinal axis X.

[0035] To facilitate its manufacture and assembly / mounting / disassembly, a turbomachine is generally modular, that is to say it comprises several modules which are manufactured independently of each other and which are then assembled together. The modularity of a turbomachine also facilitates its maintenance. In this application, we understand by "turbomachine module" a module which notably comprises a fan or propeller and a system for changing the pitch of the blades of this propeller or fan.

[0036] In [Fig. 1], the turbomachine 1 comprises a gas generator 2 upstream of which a fan 3 is mounted. The gas generator 2 typically comprises, from upstream to downstream, a low-pressure compressor 4, a high-pressure compressor 5, a combustion chamber 6, a high-pressure turbine 7 and a low-pressure turbine 8. The rotors of the low-pressure compressor 4 and the low-pressure turbine 8 are mechanically connected by a low-pressure shaft 9 so as to form a low-pressure body. The rotors of the high-pressure compressor 5 and the high-pressure turbine 7 are mechanically connected by a high-pressure shaft 10 so as to form a high-pressure body. The high-pressure body is guided in rotation about the longitudinal axis by a first bearing 11 with upstream rolling bearings and a second bearing 12 with downstream rolling bearings. The first bearing 11 is mounted radially between an intercompressor casing 13 and an upstream end of the high-pressure shaft 10.The inter-compressor casing 13 is arranged axially between the low and high pressure compressors 4, 5. The second bearing 12 is mounted radially between an inter-turbine casing 14 and a downstream end of the high pressure shaft 10. The inter-turbine casing 14 is arranged axially between the low and high pressure turbines 7, 8. The low pressure body is guided in rotation about the longitudinal axis X via a third bearing 15 with rolling bearings and a fourth, preferably double, bearing 16 with rolling bearings. The latter are mounted radially between an exhaust casing 17 and a downstream end of the low pressure shaft 9. The exhaust casing 17 is located downstream of the low pressure turbine 8. The third bearing 15 is mounted radially between an inlet casing 18 and an upstream end of the low pressure shaft 9. The high pressure shaft 10 extends radially at least partly outside the low pressure shaft 9 and are coaxial.

[0037] In another configuration not shown, the low pressure or low pressure body comprises the low pressure compressor which is connected to an intermediate pressure turbine. A free power turbine is mounted downstream of the intermediate pressure turbine and is connected to the propeller described below via a power transmission shaft to drive it in rotation.

[0038] The fan 3 shown is shrouded by a fan casing 19 which carries (with stator blades mounted downstream of the fan) a nacelle 20. The fan 3 compresses an air flow which enters the turbomachine by dividing into a primary air flow F1 and a secondary air flow F2 at a separation nozzle 21. The latter is carried by the inlet casing 18 centered on the longitudinal axis X. The inlet casing 18 is extended downstream by an external casing or inter-stream casing 22. The primary air flow F1 circulates in a primary stream 23 which passes through the gas generator 2 and escapes therefrom through a primary nozzle 24. The secondary air flow F2 circulates in a secondary stream 25 and escapes therefrom through a secondary nozzle 26. The primary stream 23 and the secondary vein 25 are separated by the inter-vein casing 22.

[0039] The fan 3 comprises a series of fan blades 30 extending radially around a fan rotor 31. The fan rotor 31 is traversed by a cylindrical fan shaft 32, centered on the longitudinal axis X. The fan shaft 32 drives the fan rotor 31 in rotation around the longitudinal axis X. The fan shaft 32 is itself driven in rotation by a power transmission shaft of longitudinal axis X via a power transmission mechanism 33. In the present example, the power transmission shaft is the low pressure shaft 9. The fan shaft 32 and the low pressure shaft 9 are coaxial. Alternatively, the power shaft is a power turbine shaft supplied with gas by the gas generator 2.

[0040] The power transmission mechanism 33 is a speed reducer 34 making it possible to reduce the rotational speed of the fan shaft 32 relative to the speed of the low pressure shaft 9. On the other hand, the speed reducer 34 allows the arrangement of a fan with a large diameter so as to increase the bypass ratio.

[0041] The reducer 34 is of the planetary gear train type. The latter is housed in a lubrication enclosure 35 in which it is lubricated. The speed reducer is connected to the fan shaft 32. Typically, the speed reducer 34 comprises a sun gear 36 (or inner planetary), satellites 37, a planet carrier 38 and an outer ring gear 39 (or outer planetary). In the present example, the sun gear 36 is centered on the longitudinal axis X and is coupled in rotation with the power shaft (here the low pressure shaft 9) along the longitudinal axis X. The latter comprises first elements intended to cooperate with second complementary coupling elements carried by the sun gear 36. The satellites 37 (in the form of pinions) are carried by the planet carrier 38 and each rotates around an axis substantially parallel to the longitudinal axis X. Each of the satellites 37 meshes with the sun gear 36 and the outer ring gear 39.The satellites 37 are arranged radially between the sun 36 and the outer ring 39. In the present example, three satellites 37 are provided. Of course, the speed reducer 34 can comprise a number of satellites greater than three.

[0042] The outer ring 39 is coupled in rotation with the fan shaft 32. The ring 39 is centered on the longitudinal axis. In this way, the solar 36 forms the input of the speed reducer 34 while the outer ring 39 forms the output thereof. The planet carrier 38 is, on the other hand, fixed relative to the ring 39. The planet carrier 38 is in particular fixed to a fixed structure of the turbomachine via a support shell 40. The latter is rigidly fixed to the inlet casing 18 of the turbomachine. The support shell 40 is also fixed to a first bearing support 41, fixed, integral with the inlet casing 18. The first bearing support 41 is installed in downstream of the speed reducer 34. Alternatively, the planet carrier 38 is fixed on a radially internal shell of the input casing 18 or directly on a second bearing support 44. This bearing support 44 described below is installed upstream of the speed reducer 34.

[0043] The third bearing 15 is mounted downstream of the speed reducer 34. Rolling guide bearings are also arranged upstream of the speed reducer 34 to guide the fan shaft 32 in rotation. These bearings are also arranged in the lubrication enclosure 35. More precisely, we can see a fifth bearing 42 with (ball) bearings just upstream of the reducer 34 and a sixth bearing 43 with (roller) bearings upstream of the bearing 42. The outer rings of these bearings are carried by the second bearing support 44, fixed, integral with the inlet casing 18. The inner rings are integral with the fan shaft 32.

[0044] With reference to Figures 1 and 2, the fan blades 30 are variable-pitch. Each fan blade 30 comprises a root 45 and a blade 46 extending radially outward from the root 45. In the example of this figure 1, the free end of the blades is delimited radially by the fan casing 19. The root 45 of each blade 30 is typically in the form of a shaft which is pivotally mounted along a setting axis C in an internal housing 47 of a ring 48. Alternatively, the root and the blade are separate, the blade 46 fitting into the root 45 via a dovetail connection. The ring 48 is integral with the fan rotor 31, is centered on the longitudinal axis and comprises several housings 47 distributed regularly around the axis X. There are as many housings 47 as there are blade roots. The setting axis C is parallel to the radial axis.The shaft of the foot 45 is pivotally mounted by means of at least two guide bearings 49 mounted in each housing 47 and in a superimposed manner along the radial axis Z. These bearings 49 are preferably, but not limited to, rolling bearings and the rolling elements here respectively comprise balls.

[0045] The fan blades are set by means of a pitch change system 50 installed in the fan rotor 31. The pitch change system 50 is arranged in particular upstream of the speed reducer 34. The pitch change system 50 comprises a control means 52 intended to act on the fan blades. The pitch change system also comprises a connecting mechanism 51 connected to the fan blades 30 and to the control means 52.

[0046] With reference to [Fig. 1], the control means 52 is arranged upstream of the speed reducer 34. The control means 52 comprises a linear hydraulic actuator with an axis coaxial with the longitudinal axis X.

[0047] The actuator comprises an annular body 53 and a movable body 54 which moves relative to the annular body 53. In the present example, the annular body 53 is integral in rotation with the fan shaft 32 and is therefore itself movable, in particular in rotation around the axis X. The movable body 54 moves in translation along the longitudinal axis X relative to the annular body 53.

[0048] The annular body 53 forms the cylinder or housing of the actuator cylinder and the movable body 54 forms the piston of the actuator cylinder.

[0049] Still in Figures 1 and 2, the movable body 54 moves axially under the action of a command from the control means 52, and in particular the pressure of a fluid circulating in the chambers of the actuator. For this, the pitch change system 50 comprises supply means ensuring the control thereof and described later in the description. The fluid received in the cavities of the actuator, located on either side of the piston, is for example a pressurized hydraulic fluid, coming from a fluid supply system 90, so that the movable body 54 occupies at least two positions. Of course, the movable body 54 occupies several intermediate positions depending on the different flight phases of the aircraft. These two positions correspond respectively to the thrust reversal position known in English as "reverse" and to the feathering position of the variable-pitch blades.The movement of the movable body 54 along the longitudinal axis X causes the movement of the connecting mechanism 51, in such a way that the latter causes the blades of the vanes to pivot and to be set around the setting axis C.

[0050] In [Fig. 1], the pitch change system 50 comprises an annular part 74 which has a general bell or flange shape and which makes it possible to connect the link mechanism 51 to the control means 52.

[0051] In [Fig.2], the connecting mechanism 51 comprises several connecting rods 82. Each connecting rod 82 comprises a first end 82a and a second end 82b opposite each other along the direction of elongation of the connecting rod 82. The direction of elongation is here substantially parallel to the longitudinal axis (in the installation situation). The direction of elongation of the connecting rods 82 may have an angle of a few degrees (for example between 1° and 25°) with the longitudinal axis. Each second end 82b of the connecting rods 82 is mounted to rotate freely with an eccentric 84 connected to the root 45 of the corresponding blade 46 via, for example, a spline connection. Each connecting rod 82 and each eccentric 84 make it possible to multiply the force required to adjust the pitch of the corresponding blade. In [Fig.2], the first end 82a is mounted to rotate freely along a substantially radial axis with a synchronization ring 80 of the pitch change system.The synchronization ring 80 is integral with the movable body 54 and is centered on the longitudinal axis X. The synchronization ring 80 is intended to drive the blades to be set simultaneously. The movement of the movable body 54 (here a . linear movement) allows the timing of all the blades 46 to be adjusted in a synchronized manner, in particular via the synchronization ring 80.

[0052] The connecting rods 82 are made of a metallic material. There are as many connecting rods as there are fan blades.

[0053] As illustrated in [Fig.2], the fan rotor may further comprise a device 180 for feathering the blades 46, in particular in the event of failure (or breakdown) of the control means 52 (for example a failure in the hydraulic supply of the control means 52). As a reminder, the feathering position corresponds to a positive setting generally substantially equal to 90°. The feathering device 180 comprises at least one lever 181 articulated around an axis G fixed relative to the rotor (and in particular the ring 48 via a casing 188). The axis G is here rectilinear and perpendicular to the axis X. The casing 188 is annular and centered on the longitudinal axis. Several levers 181 are mounted regularly, around the axis X, on the casing 188.Each lever 181 has a substantially L or V shape (in axial section), with a first branch 182 angularly spaced from a second branch 183, the first and second branches 182, 183 being connected at the level of the portion carrying the articulation axis G. The device 180 comprises a counterweight element secured to a first end 181a of the lever 181. The first end 181a is carried by the first branch 182. The counterweight element is formed by a weight 184. A second end 181b of the lever 181 is coupled (along a pivot connection of axis F) to the synchronization ring 80 via a connecting rod 185. The second end 181b is carried by the second branch 183. In the event of failure, the pitch change system 50 is subordinate to the feathering device 180.In particular, the weight 184 is capable of being moved at least into a first position (after a clockwise rotation) corresponding to a failure, under the centrifugal effect, in which the synchronization ring 80 imposes the feathering position on the blades 46, and into a second position (close to the longitudinal axis) corresponding to a thrust reversal (reverse position).

[0054] With reference to [Fig.l] and as previously announced, the turbomachine comprises a fluid supply system 90 for distributing a lubricating fluid to the various organs and / or equipment that need it, such as the control means 52, the bearings, etc. The supply system 90 comprises a supply source 91 (or a reservoir, illustrated schematically in [Fig.l]), a hydraulic pump 92 for circulating the fluid to the organs and / or equipment from the supply source 91 and a servovalve 93 for regulating the pressure of the fluid in the control means 52 according to the necessary setting. The servovalve 93 is electrically controlled by a cal electronic controller 27 of the turbomachine which is known by the acronym "ECU" for "Electronic Control Unit". The power source 91 is arranged in a fixed reference frame of the turbomachine and generally in the nacelle 20 illustrated in [Fig.l] or in the inter-vein casing 22. The pump 92 and the servovalve 93 are also arranged in the fixed reference frame of the turbomachine.

[0055] The turbomachine comprises a fluid transfer device 94, between a stator and a rotor, mounted in the supply system. The control means 52 being located in a rotating reference frame, the fluid transfer device 94 or fluid transfer bearing allows the transfer of fluid from the fixed reference frame to the rotating reference frame of the turbomachine 1. This transfer device 94 is known by the English acronym “OTB” for “OU transfer Bearing”. The fluid transfer device 94 is arranged upstream of the speed reducer 34. The location of the fluid transfer device 94 is advantageous because it makes it easier to disassemble / assemble it without intervening on the speed reducer 34. The supply system 90 also comprises several supply pipes 95 for conveying the fluid to the components and / or equipment. The pipes 95 (two in the present example) pass through the planet carrier and are connected to the servovalve 93.The planet carrier of the reducer is immobile in rotation and allows the passage of the pipes 95 through it as well as inside the fan shaft 32.

[0056] The transfer device 94 extends inside the fan shaft 32 (which is hollow) so as to reduce the axial and radial size, and more particularly inside the control means 52.

[0057] The transfer device 94 comprises a stator portion 96 and a rotor portion 97. One of the stator and rotor portions is engaged in the other, so as to reduce the size and form a compact assembly that is easy to assemble and disassemble. The stator portion 96 is mounted integrally to a fixed structure of the turbomachine. In the present example, the stator portion 96 is fixed to the planet carrier 38 via stator equipment. The stator equipment may comprise a tubular element 99. Alternatively, the stator portion 96 is fixed directly to the planet carrier 38.

[0058] The tubular element 99 is configured to provide a "flexible connection" between the stator portion 96 and the planet carrier 38 here. In this way, the risks of misalignment and constraints between the rotor portion 97 and the stator portion 96 are reduced.

[0059] The invention provides a linear hydraulic actuator that can be used in the context of a turbomachine module or a turbomachine as described above, or for another application. The actuator according to the invention can therefore be part of a control means 52 or form a control means 52 as mentioned above.

[0060] The linear hydraulic actuator according to the invention is referenced 100 in the following and a preferred embodiment is illustrated in Figures 3 and following.

[0061] The actuator 100 has a general elongated shape along an axis which is the longitudinal axis X of the turbomachine 1 in the aforementioned example.

[0062] The actuator 100 comprises:

[0063] - a tubular inner body 102 which extends along the X axis and which comprises a internal housing 104 capable of receiving a fluid transfer device 94 of the aforementioned type, i.e. a device for transferring fluid from a fixed reference point to a rotating reference point, and

[0064] - a tubular outer body 106 which extends along the X axis and around the body internal 102 and which comprises a piston 108 movable in axial translation on the internal body 102.

[0065] The internal body 102 comprises a first external cylindrical surface 102a on which the piston 108 is able to slide in translation.

[0066] The piston 108 axially separates two annular fluid cavities C1, C2 which are capable of being supplied with fluid to ensure axial translation of the piston 108 and the external body 106 on the internal body 102. The cavity C1 is for example an upstream cavity and is supplied with pressurized fluid to move the piston 108 downstream. The cavity C2 is then a downstream cavity which is supplied with pressurized fluid to move the piston 108 upstream.

[0067] The inner body 102 is shown alone in Figures 5a, 5b and 6, and the outer body 106 is shown alone in [Fig.7].

[0068] In the example shown, the internal body 102 comprises first and second adjacent axial sections T1, T2.

[0069] The first axial section T1 comprises the housing 104 and the first surface.

[0070] The second axial section T2 comprises a first cylindrical wall 110 which comprises axial grooves 112. These grooves 112 are regularly distributed around the axis X and extend over an axial dimension LL. There are 4 of them in the example shown.

[0071] L1 represents at least 30% of the total axial length or dimension L2 of the internal body 102.

[0072] The second section T2 of the internal body 102 comprises at its free end located on the side opposite the first section T1 an annular row of blind holes 114 which open radially inwards and are capable of receiving barrel nuts (not shown). The holes 114 are regularly distributed around the axis X and their number is for example greater than 12. Each of these holes 114 is associated with an axial bore 116 which is formed in the free end of the second section T2 and which opens into the corresponding hole 114. As will be seen in the following, a screw is intended to be engaged in the bore 116 and to be screwed into the barrel nut. inserted into blind hole 114.

[0073] The first section T1 of the inner body 102 is preferably of the double-skin type. It comprises an inner skin 118 which defines the aforementioned first surface 102a, and an outer skin 120 which defines a second inner cylindrical surface 102b which surrounds the first surface 102a.

[0074] The first and second surfaces 102a, 102b define between them an annular space E which receives the piston 108 and which is separated in two by the piston 108 to form the aforementioned cavities C1, C2.

[0075] The annular space E is closed at a first axial end by an annular web 122 of the internal body 102 which connects the internal 118 and external 120 skins and at one of their axial ends. The annular space E is closed at a second opposite axial end by an annular plug 124 attached and fixed to the external skin 120 of the internal body 102.

[0076] The plug 124 is shown alone in [Fig.8] and assembled to the actuator 100 in [Fig.3].

[0077] The plug 124 comprises for example an external annular flange 124a which is applied axially to an external annular flange 120a of the external skin 120 and which is fixed to this flange 120a by screws or the like which pass through orifices in the flanges 124a, 120a.

[0078] At least one annular sealing gasket 126 may be provided between the outer periphery of the plug 124 and the surface 102b. At its inner periphery, the plug 124 preferably comprises an annular dynamic sealing system 128.

[0079] The internal body 102 may further comprise a (further) annular fixing flange 130, preferably radially external, projecting from its external skin. This flange 130 is for example used to fix the actuator 100 to the shaft of the fan 32 in the application envisaged above.

[0080] Advantageously, the internal body 102 comprises first internal fluid conduits 132, the ends 132a of which open into the internal housing 104, and the opposite ends 132b of which open into one of the cavities C1 (see [Fig.5a]).

[0081] Advantageously, the internal body 102 comprises second internal fluid conduits 134, the ends 134a of which open into the internal housing 104, and the opposite ends 134b of which open into the other of the cavities C2 (see [Fig.5b]).

[0082] It is therefore understood that the cavities C1, C2 of the actuator 100 are supplied with fluid by conduits 132, 134 integrated into the actuator 100, which is particularly advantageous. For this, and as illustrated in the drawings, the skins 118, 120 as well as the web 122 can be thickened to allow the conduits to be produced in their thicknesses. The extra thickness can be located as illustrated in FIGS. 5a, 5b and 6 and result in axial ribs projecting from the external surface of the outer skin 120, in which part of the conduits 132 are formed, or by radial ribs projecting from the web 122, in which part of the conduits 134 are formed.

[0083] It is also understood that the pipes 132, 134 are themselves supplied with fluid by the transfer device 94 which is engaged in the housing 104.

[0084] In the figures, it can be seen that each of the conduits 132, 134 has a general C-shape and comprises an internal portion which is formed in the internal skin 118 and which opens radially inwards into the housing 104 via the ends 132a, 134a, an external portion which is formed in the external skin 120 and which opens radially inwards into one of the cavities C1, C2 via the ends 132b, 134b, and a lateral portion connecting the internal and external portions which is formed in the web 122.

[0085] The internal body 102 may further comprise third internal fluid conduits 136, the ends 136a of which open into the internal housing 104, and the opposite ends 136b of which open radially inwards, for example to supply a system Z for locking the pitch of the blades of the pitchlock type schematically represented by a rectangle in [Fig.l 1]. This system Z is fixed to the internal body 102 of the actuator 100 at its end comprising the holes 114 for receiving the barrel nuts. This system Z comprises for example an external annular flange which is applied axially to the free end of the internal body 102 of the actuator 100 and which comprises orifices for the passage of the aforementioned screws which are screwed into the barrel nuts carried by the internal body 102.

[0086] This fixing area of ​​the Z system is accessible during maintenance and the barrel nut fixing method facilitates assembly / disassembly.

[0087] The conduits 136 have, for example, a general L shape and are formed in the internal skin 118.

[0088] The first and second sections T1, T2 of the internal body 102 are preferably formed from a single piece, for example by additive manufacturing.

[0089] The outer body 106 comprises a second cylindrical wall 140 which surrounds the first cylindrical wall 110 and which is connected to the piston 108.

[0090] In the example shown, the external body 106 comprises a tubular portion, a part of which forms the second wall 140 and a longitudinal end of which forms the piston 108 or is connected to said piston 108.

[0091] The external body 106 carries rolling rollers 142 which are intended to be housed in the grooves 112 of the internal body 102 and which are capable of cooperating by rolling with these grooves 112 to guide the translation of the external body 106 on the internal body 102 while blocking the rotation of the external body 106 with respect to the internal body 102 around the axis X.

[0092] An example of a roller 142 is illustrated in Figures 9 and 10.

[0093] A roller 142 comprises for example an external ring 144 which has an external rolling surface and which is guided in rotation by a rolling bearing 146, preferably needle bearing, or smooth located at one end of a finger 148. The opposite end of the finger 146 is threaded and receives a nut 150.

[0094] In the example shown, the external body 106 comprises radial through-holes 152 for mounting the rollers 142. The threaded ends of the fingers 148 of the rollers 142 are inserted into these holes 152, from the inside of the external body 106 and the nuts 150 are screwed onto these ends and bear radially on the external face of the external body 106. The holes 152 are formed in the wall 140 in the example shown.

[0095] In practice, it may be necessary to mount the external body 106 on the internal body 102 before mounting the rollers 142. The threaded ends of the fingers 148 of the rollers 142 are then inserted into the orifices 152, from the inside of the bodies 102, 106 and through the grooves 112 of the internal body 102, then the nuts 150 are screwed onto these ends and bear radially on the external face of the external body 106.

[0096] The tubular portion of the external body 106 comprises an annular fixing flange 154, preferably radially external, at its longitudinal end opposite the piston 108.

[0097] As can be seen in [Fig. 11], this flange 154 can be used to connect and fix the external body 106 of the actuator 100 to the annular part 74 described with reference to [Fig.l]. The external periphery of this part 74 is connected to the aforementioned synchronization ring 80.

[0098] As seen in [Fig. 3], the tubular portion of the external body 106 is able to slide axially inside the plug 124, and more particularly between the plug 124 and the surface 102a of the internal body 102. The sealing system 128 cooperates with the external surface of the external body 106 to prevent or limit oil leaks during the translation of the piston 108.

[0099] The piston 108 may further comprise at least one dynamic sealing system 158 intended to cooperate with the surface 102b of the internal body 102.

[0100] The piston 108 or the external body 102 may further comprise a dynamic sealing system 156 intended to cooperate with the surface 102a of the internal body 102.

[0101] The tubular portion of the outer body 102 may be formed in a single piece, for example by additive manufacturing.

[0102] The present invention thus proposes to integrate several functions or functionalities into the internal body 102 of the actuator 100, and for example:

[0103] - the connection with the fan shaft 32, by the flange 130,

[0104] - the guidance of the piston 108, by the surface 102a or even the surface 102b,

[0105] - the circulation of the fluid from the transfer device 94 to the cavities C1, C2, via internal pipes 132, 134,

[0106] - the guidance of the rollers 142 by the grooves 112, etc.

[0107] The present invention also relates to an assembly comprising an actuator 100 and a fluid transfer device 94 of the aforementioned type, as well as a turbomachine module, comprising a propeller or fan as described above and a system for changing the pitch of the propeller blades, this system comprising an actuator 100 as mentioned above.

Claims

Claims

1. Linear hydraulic actuator (100), in particular for an aircraft turbomachine (1), this actuator (100) having a generally elongated shape along an axis (X) and comprising: - a tubular internal body (102) which extends along the axis (X) and which comprises an internal housing (104) capable of receiving a device (94) for transferring fluid from a fixed reference point to a rotating reference point, the internal body (102) comprising a first external cylindrical surface (102a), - a tubular external body (106) which extends along the axis (X) and around the internal body (102) and which comprises a piston (108) movable in axial translation on the first surface (102a), this piston (108) axially separating two annular fluid cavities (C1, C2) which are capable of being supplied with fluid to ensure axial translation of the piston (108) and the outer body (106) on the inner body (102),characterized in that the inner body (102) comprises a first cylindrical wall (110), and the outer body (106) comprises a second cylindrical wall (140) which surrounds the first cylindrical wall (110), one of these first and second walls (110, 140) comprising axial grooves (112) and the other of these first and second walls (140, 110) carrying rolling rollers (142) which are housed in these grooves (112) and which are capable of cooperating by rolling with these grooves (112) to guide the translation of the outer body (106) on the inner body (102) while blocking the rotation of the outer body (106) with respect to the inner body (102).,

2. An actuator (100) according to claim 1, wherein the inner body (102) comprises adjacent first and second axial sections (T1, T2), the first axial section (T1) comprising said housing (104) and said first surface (102a), and the second axial section (T2) comprising said first wall (110).

3. Actuator (100) according to claim 2, in which the second section (T2) of the internal body (102) comprises at its free end located on the side opposite the first section (T1) an annular row of blind holes (114) which open radially inwards and are capable of receiving barrel nuts.

4. Actuator (100) according to claim 2 or 3, in which the first section (T1) of the internal body (102) is of the double-skin type and comprises an inner skin (118) defining said first surface (102a), and an outer skin (120) defining a second inner cylindrical surface (102b) which surrounds the first surface (102a), the first and second surfaces (102a, 102b) defining between them an annular space (E) which receives said piston (108) and which is separated in two by said piston (108) to form said cavities (Cl, C2).

5. Actuator (100) according to claim 4, in which the annular space (E) is closed at a first axial end by an annular web (122) of the internal body (102) which connects the internal and external skins (118, 120), and at a second opposite axial end by an annular plug (124) attached and fixed to the external skin (120) of the internal body (102).

6. Actuator (100) according to claim 4 or 5, wherein the inner body (102) comprises an annular fixing flange (130), preferably radially external, projecting from its outer skin (120).

7. Actuator (100) according to one of the preceding claims, in which the internal body (102) comprises first internal fluid conduits (132) whose ends (132a) open into said internal housing (104), and whose opposite ends (132b) open into one of the cavities (C1), and second internal fluid conduits (134) whose ends (134a) open into said internal housing (104), and whose opposite ends (134b) open into the other of the cavities (C2).

8. Actuator (100) according to claim 7 as dependent on one of claims 3 to 6, in which the first and second conduits (132, 134) are formed in said skins (118, 120), or even in said web (122).

9. Actuator (100) according to claim 7 or 8, in which the internal body (102) comprises third internal fluid conduits (136) whose ends (136a) open into said internal housing (104), and whose opposite ends (136b) open radially inwards.

10. Actuator (100) according to one of claims 2 to 9, in which the first and second sections (T1, T2) of the internal body (102) are formed in a single piece.

11. Actuator (100) according to one of the preceding claims, in which the external body (106) comprises a tubular portion, a part of which forms said second wall (140) and a longitudinal end of which tudinal forms said piston (108) or is connected to said piston (108).

12. Actuator (100) according to claim 11, wherein the tubular portion of the external body (106) comprises an annular fixing flange (154), preferably radially external, at its longitudinal end opposite said piston (108).

13. Actuator (100) according to claim 11 or 12, dependent on claim 5, in which the tubular portion of the external body (106) is capable of sliding axially inside the plug (124).

14. Actuator (100) according to one of claims 11 to 13, in which the tubular portion of the external body (106) is formed in a single piece.

15. Turbomachine module, comprising a propeller comprising a plurality of variable-pitch blades (46), and a system for changing the pitch of the propeller blades, this system comprising an actuator (100) according to one of the preceding claims.

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