Planet carrier for mechanical reduction gear of aircraft turbine engine, reduction gear and aircraft turbine engine comprising reduction gear

Abstract

Disclosed is a planet carrier (213) for a mechanical reduction gear (10, 110) of an aircraft turbine engine (1), the planet carrier comprising:-a first disc (236), the first disc extending about a first axis (X) and perpendicular to the first axis (X), the first disc (236) comprising first apertures (292), each centered about a second axis (Y) parallel to the first axis (X),-a second disc (238), each centered about a second axis (Y) parallel to the first axis (X), a second disk (238) extending centered on the first axis (X), parallel to and at a distance from the first disk (236), the second disk (238) comprising second apertures (294), respectively centered on a second axis (Y), the number of the second apertures (294) being equal to the number of the first apertures (292),-a bridge connector (296), a bridge connector (296) extends between and connects the first and second disks (236, 238), the bridge connector (296) being formed as a unitary piece with the first and second disks (236, 238).

Description

Technical Field

[0001] The present invention relates to a planetary carrier and a mechanical reduction gear for an aircraft turbine engine, and a turbine engine comprising such a planetary carrier or reduction gear. Background Technology

[0002] The prior art includes, in particular, documents FR-A1-2 987 416, FR-A1-2 853 382, ​​FR-A1-3 041054, FR-A1-3 073 915, FR-A1-3 084 428, JP-A-2006 / 009994, EP-B1-4 056 469, US-A-3,227,006, FR-A1-3 132 133 and US-A-5,466,198.

[0003] The function of mechanical reduction gears is to change the gear ratio and torque between the input and output shafts of a mechanism.

[0004] New-generation twin-flow turbine engines, especially those with high bypass ratios, include mechanical reduction gears to drive the fan shaft. The typical purpose of reduction gears is to convert the rotational speed (referred to as high speed) of the power turbine shaft into a slower speed used to drive the fan shaft.

[0005] Such a reduction gear consists of a central pinion called the sun gear, a ring gear, and pinions called planetary gears, which mesh between the sun gear and the ring gear. The planetary gears are held in place by a frame called a planet carrier. The sun gear, ring gear, and planet carrier are planetary gears because their axes of rotation coincide with the longitudinal axis of the turbine engine. Each planetary gear has a different axis of rotation and is equidistant from the same operating diameter around the axis of the planetary gear. These axes are parallel to the longitudinal axis of the turbine engine.

[0006] Several reduction gear architectures exist. In the prior art of two-flow turbine engines, the reduction gears are planetary or rotary reduction gears. In other similar applications, there are architectures referred to as differential or "compound" reduction gears.

[0007] - In a planetary reduction gear, the planet carrier is stationary, and the ring gear is the output shaft of the device, which rotates in the opposite direction to the sun gear.

[0008] In a rotary gear reducer, the ring gear is stationary, and the planet carrier is the output shaft of the device, which rotates in the same direction as the sun gear.

[0009] - In a compound reduction gear, no components are rotatably attached. The ring gear rotates in the opposite direction to the sun gear and planet carrier.

[0010] A reduction gear can consist of one or more meshing stages. This meshing is ensured in different ways, such as by contact, friction, or by a magnetic field. Several types of contact meshing exist, such as contact meshing by spur teeth or herringbone teeth.

[0011] The planetary carrier can be a single-piece planetary carrier or it can be in the form of a cage and a cage bracket. The cage includes a cavity in which the sun gear, planet gears, and their guide bearings are housed. The sun gear includes internal splines for coupling to a first shaft of the turbine engine, and the cage bracket includes a cylindrical section that includes external splines for coupling to another shaft.

[0012] The connection between the cage and the cage bracket is typically a rigid connection. Alternatively, a technique is conceivable in which the cage is connected to the cage bracket via a “flexible” connection, as described in document FR-A1-2 853 382. In this case, the cage bracket includes axially arranged fingers in an annular row carrying first connecting elements. These first connecting elements cooperate with second connecting elements mounted in the cage housing to form a flexible connection between the cage bracket and the cage, thereby allowing at least one degree of freedom.

[0013] During operation, the planetary carrier is subjected to forces that tend to deform it. This is the case for integral planetary carriers or cages and cage supports. These deformations cause planetary gear misalignment, resulting in meshing degradation, and the risk of asymmetrical oil film when using sliding or hydrodynamic planetary gear guide bearings, or the risk of roller misalignment when using planetary gear rolling guide bearings. These forces and strains must be balanced to limit or even counteract these effects.

[0014] The planetary carrier also includes orifices to accommodate the ends of the planetary gear guide bearings. These orifices can be machined, and machining tolerances can lead to dimensional and positional errors within them. To reduce these positional tolerances, the orifices can be ground, which is industrially limited. The material of the planetary carrier can also be chosen to reduce its stiffness, for example, by using titanium or aluminum instead of steel. However, this introduces additional constraints (machinability, mechanical strength, tribological behavior, etc.).

[0015] Misalignment of planetary gear bearings (whether sliding or rolling) and the resulting misalignment of the planetary gears themselves creates internal overload on at least one planetary gear in a reduction gear. This can mean that the components of the reduction gear (teeth, sliding and rolling bearings) become too large, thus negatively impacting the weight and performance of the reduction gear.

[0016] To address this need, the present invention provides a simple, effective, and economical solution. Summary of the Invention

[0017] This invention relates to a planetary carrier for a mechanical reduction gear in an aircraft turbine engine, the planetary carrier comprising: - A first disc, extending perpendicularly to and centered on a first axis or central axis, includes a first aperture or bearing aperture centered on a second axis or bearing axis, the second axis or bearing axis being distributed around and parallel to the first axis. - A second disk, centered on the first axis, extending parallel to and axially away from the first disk, includes second orifices or bearing orifices centered on the second axis, the number of second bearing orifices being equal to the number of first bearing orifices. - Bridge connector, which extends between the first and second discs and connects the first and second discs together.

[0018] The principle of this invention lies in locally softening the planetary carrier, particularly near the receiving bore used to house the planetary gear shaft. Internal overload is caused by positional tolerances in the planetary bores used to house the planetary gear shaft. A planetary gear offset from its perfect nominal position can experience a positive or negative load difference, which can be as high as 10% or more, depending on the direction of the offset. This effect is amplified by the local stiffness of the planetary carrier located between two consecutive planetary gears. Therefore, the lower the stiffness, the smaller the overload. Significant weight savings can be achieved by reducing the design load.

[0019] According to a first aspect of the invention, at least one disc in the disc includes alternating concave and convex curved sections on each of the inner and outer peripheral edges of the disc, the convex curved sections of the inner peripheral edge and the concave curved sections of the outer peripheral edge being radially aligned with respect to a central axis and extending radially inward and radially outward of bearing orifices of the disc, respectively, the concave curved sections of the inner peripheral edge and the convex curved sections of the outer peripheral edge being radially aligned with respect to the central axis, and the number of concave and convex curved sections on the inner and outer peripheral edges of the disc being equal to the number of bearing orifices of the disc.

[0020] Therefore, the planetary architecture according to the invention improves the operating behavior of the planetary carrier, particularly enhancing its resistance to deformation caused by force transmission. This reduces the impact on bearings, for example, reducing the impact on bearing misalignment or asymmetry.

[0021] This is made possible by the inner and outer peripheral edges of a disk, or each disk, of a specific shape. Each of these edges comprises alternating concave and convex curved sections. The number of concave curved sections on the inner peripheral edge is equal to the number of convex curved sections on that edge, and also equal to the number of orifices in the disk. The number of concave curved sections on the outer peripheral edge is equal to the number of convex curved sections on that edge, and also equal to the number of orifices in the disk.

[0022] The concave curved section of the inner peripheral edge and the convex curved section of the outer peripheral edge are radially aligned and located between the orifices in the disk. The convex curved section of the inner peripheral edge and the concave curved section of the inner peripheral edge are radially aligned and located radially on both sides of the orifice of the disk, respectively.

[0023] The first aspect involves reducing the thickness or banding of the material at the planetary carrier / bearing axis interface in the radial plane. Each banding can be reduced to the minimum required to maintain the receiving orifice for accommodating the corresponding bearing.

[0024] According to a second aspect of the invention, at least one disc in the disc has bearing orifices distributed in pairs, each pair of bearing orifices comprising two circumferentially adjacent bearing orifices, the disc or each disc comprising a pair of bearing orifices, the pair of bearing orifices comprising a first through hole located between the bearing orifices in each pair of bearing orifices, the first through hole intersecting a first plane and a second plane, the first plane extending radially relative to a central axis and located at a distance equidistant from the pair of bearing orifices, the second plane passing through the bearing axis of the pair of bearing orifices, the first plane being a first symmetric plane of the hole.

[0025] Therefore, the planetary architecture according to the invention improves the operating behavior of the planetary carrier, particularly enhancing its resistance to deformation caused by force transmission. This reduces the impact on bearings, for example, reducing the impact on bearing misalignment or asymmetry.

[0026] The first hole is only for load reduction and does not have any additional or other functions, such as an attachment hole. Therefore, each first hole is preferably a smooth hole, i.e., without threads.

[0027] A second aspect of the invention allows for softening of the region between these orifices at approximately halfway between them. This increases the flexibility of the region in a tangential plane equidistant from the two orifices. The optimal region is located at the intersection of a plane passing through the center of the two orifices and a plane of symmetry of the two orifices. The presence of orifices at a distance from the orifices also helps to avoid excessive local deformation, which can lead to fretting between the bearing and the planetary carrier.

[0028] These two aspects and features of the present invention can be combined together.

[0029] This invention provides many benefits, including: - Better adapts to the displacement applied to the interface of the reduction gear. - Reduce planetary gear overload. - Reduce the weight of the planetary carrier. - Improve the dynamic behavior of the planetary carrier. - etc.

[0030] This invention is compatible with: - Single-stage or multi-stage reduction gears; - Planetary, rotary, or compound reduction gears; - Straight teeth, spiral teeth, or herringbone teeth; - Any type of integrated planetary carrier or cage and cage bracket; - All types of planetary gear guide bearings, such as rolling elements or hydrodynamic bearings.

[0031] The planetary carrier according to the invention may include one or more of the following characteristics, which may be employed individually or in combination with each other: - The bridge connector is integrated with the first and second discs as a single unit; - The convex curved section of the inner peripheral edge extends around the bearing axis of the bearing bore of the disc; - The angular range of the convex curved section of the inner peripheral edge around the central axis is smaller than the angular range of the concave curved section of the inner peripheral edge around the central axis. - The angle range of the concave curved section of the outer periphery around the central axis is less than or equal to the angle range of the convex curved section of the outer periphery around the central axis. - The angular range of the convex curved section of the inner peripheral edge around the first axis is equal to + / -10% of the angular range of the concave curved section of the outer peripheral edge around the central axis, and / or, the angular range of the concave curved section of the inner peripheral edge around the central axis is equal to + / -10% of the angular range of the convex curved section of the outer peripheral edge around the central axis; - The top of the convex curved section of the inner peripheral edge is located on a circumference with a first diameter centered on the central axis, and the top of the concave curved section of the inner peripheral edge is located on another circumference with a second diameter centered on the central axis. Half of the difference between the second diameter and the first diameter is less than or equal to the minimum radial thickness of the material of the disk surrounding the bearing orifice of the disk at the level of the inner peripheral edge. - The top of the concave curved section of the outer periphery is located on a circumference with a first diameter centered on the central axis, and the top of the convex curved section of the outer periphery is located on another circumference with a second diameter centered on the central axis. Half of the difference between the second diameter and the first diameter is greater than or equal to the minimum radial thickness of the material of the disk surrounding the bearing orifice of the disk at the level of the outer periphery. - The radius of curvature of the convex curved section of the inner peripheral edge is smaller than the radius of curvature of the concave curved section of the inner peripheral edge. - The radius of curvature of the concave curved section of the outer perimeter is equal to + / - 10% of the radius of curvature of the convex curved section of the outer perimeter; - The planet carrier has a maximum radial dimension at the level of the orifice in the disk, which is smaller than the maximum radial dimension of the planet carrier between the orifices; - All concave curved sections of the inner periphery are located on the same circumference centered on the first axis; - All the convex curved sections of the outer periphery are located on the same circumference centered on the first axis; - The first plane is also the plane of symmetry of the pair of orifices; - The second plane is also the plane of symmetry of the hole; - Each hole has a circular shape centered at the intersection between the first plane and the second plane; - Each hole has a rounded oval shape, including a larger lateral dimension extending along the first plane; - Each hole is a rectangular shape with rounded corners; - Each hole includes a radially inner edge that is convexly curved around a first axis, a radially outer edge that is concavely curved around the first axis, a first lateral edge that is convexly curved around the second axis of the first hole in the pair of holes, and a second lateral edge that is convexly curved around the second axis of the second hole in the pair of holes; - A disc including a pair of bearing bores or each disc including at least one additional through hole circumferentially located between each pair of bearing bores, the at least one additional through hole being radially located above or below the first bore and intersecting the first plane; - The first hole and the additional holes, or each additional hole, have the same shape and size; - A disk comprising a pair of bearing bores or each disk comprising at least one through opening circumferentially located between each pair of bearing bores, the first plane being also the plane of symmetry of the opening; - The disc or each disc has a material thickness measured in a radial direction relative to the central axis between the inner peripheral edge of the disc and the first hole, which is less than the material thickness measured in the same direction between the first hole and the opening; - The planetary carrier is a one-piece planetary carrier; - The planetary carrier is a type of planetary carrier with a cage and a cage bracket, and two disks and a bridge connector form the cage.

[0032] The present invention also relates to a mechanical reduction gear for an aircraft turbine engine, the mechanical reduction gear comprising the planetary carrier as described above, and the reduction gear further comprising: - The sun gear, centered on the central axis, is mounted between the disks of the planet carrier. - Planetary gears, mounted between disks of a planetary carrier with the bearing axis as the center, are guided to rotate by bearings respectively housed in the first and second bearing holes of the disks. - Ring gear, which extends around the central axis and around the sun gear and planetary gear, with the planetary gear meshing with the sun gear and ring gear.

[0033] The present invention also relates to a turbine engine, particularly a turbine engine for an aircraft, the turbine engine comprising the reduction gear as described above. Attached Figure Description

[0034] Further features and advantages will become apparent from the following description of non-limiting embodiments of the invention with reference to the accompanying drawings, in which: [ Figure 1 ] Figure 1 This is a schematic axial cross-sectional view of a turbine engine using the present invention; [ Figure 2 ] Figure 2 This is a schematic axial sectional view of a mechanical reduction gear; [ Figure 3 ] Figure 3 It is a perspective view of the cage and cage bracket assembly that form the planetary carrier for mechanical reduction gears; [ Figure 4 ] Figure 4 yes Figure 3 A partial axial sectional view of a portion of the planet carrier shown; [ Figure 5 ] Figure 5 yes Figure 4 Detailed view; [ Figure 6 ] Figure 6 yes Figure 3 A schematic front view of the planetary carrier shown; [ Figure 7 ] Figure 7 It is similar to Figure 6 The view shows an embodiment of the planetary carrier according to the present invention; [ Figure 8 ] Figure 8 yes Figure 7 A larger scale view of a portion; [ Figure 9 ] Figure 9 It is similar to Figure 6 The view shows another embodiment of the planetary carrier according to the present invention; [ Figure 10 ] Figure 10 yes Figure 9 A portion of a larger scale view, [ Figure 11 ] Figure 11 It is similar to Figure 10 The view illustrates an alternative embodiment of the invention. [ Figure 12 ] Figure 12 It is similar to Figure 10 The view illustrates another embodiment of the invention. [ Figure 13 ] Figure 13 It is similar to Figure 10 The view shows another embodiment of the invention. Detailed Implementation

[0035] Figure 1 A turbine engine 1 is described, which typically includes a fan S, a low-pressure compressor 1a, a high-pressure compressor 1b, an annular combustion chamber 1c, a high-pressure turbine 1d, a low-pressure turbine 1e, and an exhaust nozzle 1h. The high-pressure compressor 1b and the high-pressure turbine 1d are connected by a high-pressure shaft 2, and together they form a high-pressure (HP) body. The low-pressure compressor 1a and the low-pressure turbine 1e are connected by a low-pressure shaft 3, and together they form a low-pressure (BP) body.

[0036] Fan S is driven by fan shaft 4, which is connected to BP shaft 3 via mechanical reduction gear 10. This reduction gear 10 is typically a planetary or rotary reduction gear.

[0037] Although the following description refers to reduction gears of the planetary or cyclic type, the following description also applies to mechanical differentials, in which the three basic elements of a mechanical differential, namely the planet carrier, the ring gear and the sun gear, can be rotatable, and the rotational speed of one of these elements depends in particular on the speed difference between the other two elements.

[0038] The reduction gear 10 is located in the upstream section of the turbine engine. A fixing structure is arranged to form a housing E surrounding the reduction gear 10. Here, the fixing structure schematically includes an upstream portion 5a and a downstream portion 5b that constitute the engine housing or stator 5. Here, the housing E is closed upstream by a washer at the level of a bearing that allows the fan shaft 4 to pass through, and downstream by a washer at the level of a bearing through which the BP shaft 3 passes.

[0039] Figure 1 A portion of a reduction gear 10 is shown. The reduction gear 10 can take different configurations depending on whether certain components are stationary or rotating. The input end of the reduction gear 10 is connected to the BP shaft 3, for example, via a spline 7. Therefore, the BP shaft 3 drives a planetary pinion called the sun gear 11. Traditionally, the axis of rotation of the sun gear 11 coincides with the axis X of the turbine engine 1. The sun gear 11 drives a series of pinions called planetary gears 12, which are circumferentially spaced at equal intervals around the same diameter about the axis of rotation X. This diameter is equal to twice the distance between the operating centers of the sun gear 11 and the planetary gears 12. For this type of application, the number of planetary gears 12 is typically limited to between three and seven.

[0040] The assembly consisting of planetary gears 12 is held by a frame called planet carrier 12. Each planetary gear 12 rotates about its own axis Y and meshes with a ring gear 14.

[0041] At the output of the reduction gear 10, there is: In the rotary configuration, the assembly consisting of planetary gears 12 drives the planetary carrier 13 to rotate about the axis X of the turbine engine. The ring gear 14 is attached to the engine housing or stator 5 via the ring gear bracket 15, and the planetary carrier 12 is attached to the fan shaft 4.

[0042] In the planetary configuration, the assembly consisting of planetary gears 12 is held by a planetary carrier 12 attached to the engine housing or stator 5. Each planetary gear drives an annular gear mounted to the fan shaft 4 via an annular gear carrier 15.

[0043] Each planetary gear 12 is mounted such that it can rotate freely about axis Y by means of bearing 8. The axis of rotation Y of the planetary gear 12 is distributed about and parallel to axis X. For example, the bearing 8 is of the type of rolling bearing or hydrodynamic bearing. Each bearing 8 is mounted on a physical shaft 13a of the planet carrier 12, and all these physical shafts 13a are positioned relative to each other using one or more structural frames of the planet carrier 12. The number of physical shafts 13a and bearings 8 is equal to the number of planetary gears 12. The shafts 13a and frames may be divided into several parts for operation, installation, production, inspection, repair, or replacement.

[0044] For the same reasons mentioned above, the teeth of the reduction gear can be divided into several paddle-shaped sections. In our example, the operation of a reduction gear 10 with several paddle-shaped sections is described in detail, wherein the ring gear of the reduction gear 10 is divided into two semi-ring gears: ° The first half of the ring gear 14a includes a rim 14aa and a half of the attachment flange 14ab. The front paddle portion of the teeth of the reduction gear is located on the rim 14aa. This front paddle portion meshes with the front paddle portion of the planetary gear 12, which meshes with the front paddle portion of the sun gear 11.

[0045] ° The rear half of the ring gear 14b includes a rim 14ba and a half of the attachment flange 14bb. The rear paddle portion of the gear teeth is located on the rim 14ba. This rear paddle portion meshes with the rear paddle portion of the planetary gear 12, which meshes with the rear paddle portion of the sun gear 11.

[0046] Half of the attachment flange 14ab of the front ring gear 14a and half of the attachment flange 14bb of the rear ring gear 14b form the attachment flange 14c of the ring gear. For example, the ring gear 14 is attached to the ring gear carrier 15 by assembling the attachment flange 14c of the ring gear and the attachment flange 15a of the ring gear carrier using bolts. In the following text, half of the flange is referred to as a flange.

[0047] Figure 1 The arrows in the diagram illustrate the delivery of oil in the reduction gear 10. Oil reaches the reduction gear 10 from the stator portion 5 in the turbine stator blades 16 via various pathways, which will not be specifically described in this view because they are specific to one or more types of architectures. The turbine stator blades 16 are divided into two sections, each repeated by the same number of planetary gears. The injector 17a functions to lubricate the teeth, and the arm 17b functions to lubricate the bearing 8. Oil is delivered toward the injector 17a to be exposed through the end 17c for lubrication of the teeth. Oil is also delivered toward each arm 17b and flows through the supply port 17d of the bearing 8. The oil then flows through the shaft 13a in one or more buffer areas 13b and then is exposed through the orifice 13c for lubrication of the bearing 8 of the planetary gears.

[0048] In the example shown, Figure 2 The planetary carrier 13 is formed as a single unit.

[0049] exist Figures 3 to 5 In this context, the elements already described above are represented by adding one hundred to the same label.

[0050] Figures 3 to 5 The specific technology of planetary carrier 113 is depicted, which includes a cage 120 and a cage bracket 122 connected by a ball joint.

[0051] The retainer 120 includes two radial annular disks or walls 136, 138 that are parallel to each other and perpendicular to the axis X, and a cylindrical wall 140 extending between the outer peripheries of these disk walls 136, 138.

[0052] Here, the cylindrical wall 140 is a double-skin type wall and includes an outer skin 140a interrupted by an opening 143 and an inner skin 140b interrupted by the same opening 143. The outer skin 140a, divided by five openings 143, forms five outer bridge connectors, and the inner skin 140b, divided by five openings 143, forms five inner bridge connectors. Each pair of lower and upper bridge connectors forms a U-shaped clamp to receive the fingers 182 of the retainer bracket 122. In other words, a housing 180 for receiving the fingers 182 of the retainer bracket 122 is defined between each pair of bridge connectors. The bridge connectors ensure structural connection between walls 136 and 138. Elliptical openings 180a are formed in at least one of the walls 136 and 138 to allow the fingers 182 to pass between the inner and outer bridge connectors. These openings 180a open into the housing 180.

[0053] Therefore, the cage 120 includes housings 180 arranged in an annular pattern. These housings 180 receive axial fingers 182, which are fixed to a generally radial annular wall 182a of the cage bracket 122. The wall 182a is located at the axial end of the cage bracket 122. The fingers 182 extend axially from the wall 182a and engage in the housings 180 by axial translation.

[0054] Each finger 182 substantially includes, in its central portion, a mounting ring 184 for a ball joint 186, the mounting ring 184 being configured to pass through a cylindrical pin 188 carried by a retainer 120.

[0055] Ring 184 has a generally radial orientation relative to axis X. Ring 184 is typically cylindrical in shape. The thickness of retainer 120 and ball joint 186, measured radially relative to axis X, is less than the distance between bridge connectors or the radial thickness of elliptical opening 180a, such that retainer 120 and ball joint 186 can simultaneously engage in the housing with the fingers 182 supporting these components.

[0056] Each housing 180 is pierced by a pin 188, which is oriented generally radially relative to the axis X. Each pin 188 includes a cylindrical body 188a, which is connected at an axial end (here, the axial end radially inward) to an outer annular collar 188b. Here, the pin 188 engages by radially translating from the inside through a radial orifice of the bridge connector, and its collar 188b is configured to be radially supported on the flat surface 191 of the outer bridge connector of the retainer 120. After the pin 188 is inserted into the orifice of the bridge connector, the collar 188b is attached to the bridge connector, for example, by a threaded connection, until it contacts the outer bridge connector.

[0057] Figure 6 Details of the disks or walls 136, 138 of the planet carrier 113 are shown. In these figures, it can be seen that each of the walls 136, 138 includes a first aperture 192, 174 centered on the axis of rotation Y of the planetary gear of the reduction gear. In the example shown, the number of apertures 192, 194 in each of the walls 136, 138 is five. Apertures 192 and 194 do not necessarily have the same diameter.

[0058] When the discs or walls 136, 138 include arrangements or recesses surrounding the orifices 192, 194, these arrangements and recesses are generally symmetrical with respect to the planes passing through the axes Y and X of the orifice. This is especially true for the opening 180a.

[0059] For example, in Figure 6 As can be seen, the openings 180a are arranged symmetrically with respect to the plane P of the axis X passing through the reduction gear and the axis Y of the orifices 192 and 194 located between these openings 180a.

[0060] The walls 136, 138 of the disc may also include attachment holes 196. These holes 196 are configured to receive attachment elements such as screws, for example, attachment elements that can be used to attach another component (such as a lubricant dispenser) to the planet carrier 113.

[0061] When plane H is drawn through the axis Y of two circumferentially adjacent openings 192 or 194, it can be seen that opening 180a and attachment hole 196 do not intersect these planes. It can also be seen that the inner circumferential edge 198 and outer circumferential edge 199 of the walls 136 and 138 of the disk are perfectly circular and centered on axis X.

[0062] This invention is an improvement on the planetary carrier of a mechanical reduction gear used in an aircraft turbine engine.

[0063] The planetary frame can be as follows: Figure 2 The integrated planetary carrier shown, or as... Figures 3 to 6The planetary carrier shown is of the type of cage and cage bracket. Therefore, with Figures 2 to 6 The foregoing description is used to illustrate and describe the present invention.

[0064] Furthermore, the planetary carrier according to the present invention can be equipped with, for example... Figure 1 The reduction gear of the turbine engine is shown. Therefore, the above is related to... Figure 1 The related descriptions can also be used to illustrate and describe the present invention.

[0065] Figure 7 and Figure 8 A first embodiment of a planetary carrier 213 according to the present invention is shown. The planetary carrier 213 may be a one-piece planetary carrier or have a cage 220 and a cage bracket.

[0066] In these figures, the elements already described above are represented by adding one hundred more to the same label.

[0067] In these diagrams, planetary carrier 213 includes: - A first bearing housing 236 extends perpendicularly to and centered on axis X, which is referred to as the first axis or central axis. The first bearing housing 236 includes first bearing orifices 292 centered on axis Y, which is referred to as the bearing axis or second axis. Axis Y is parallel to and arranged around axis X. - A second disc 238, centered on axis X, parallel to disc 236 and located at a certain distance from disc 236, includes second bearing orifices 294 centered on axis Y, the number of second bearing orifices 294 being equal to the number of first bearing orifices 292, and... - Bridge connector 296, which extends between and connects disks 236 and 238 together, and these bridge connectors 296 are integrated with disks 236 and 238.

[0068] In the diagram, one of the two disks 236 and 238 can be seen. However, due to the similarity between the two disks 236 and 238, the two disks 236 and 238 can have the same characteristics.

[0069] Referring to the position of the reduction gear in the turbine engine and the gas flow in the turbine engine, the first disc 236 is, for example, the front disc or the upstream disc, and the second disc 238 is, for example, the rear disc or the downstream disc.

[0070] Orifices 292 and 294 are used to mount planetary gears, particularly planetary gear guide bearings, in the planet carrier 213. The bearings include longitudinal ends received within these orifices 292 and 294. For example, the bearings can be sliding bearings (hydrodynamic bearings) or rolling bearings. These bearings are not shown in the figures.

[0071] At least one of the disks 236 and 238 includes alternating concave curved sections 298a and 299a and convex curved sections 298b and 299b on each of the circumferential edges 298 and 299 of the disk.

[0072] The convex curved section 298b of the inner peripheral edge 298 and the concave curved section 299a of the outer peripheral edge 299 are radially aligned with respect to the central axis X, and extend inside and outside the orifices 292 and 294 of the disks 236 and 238, respectively.

[0073] The concave curved section 298a of the inner peripheral edge 298 and the convex curved section 299b of the outer peripheral edge 299 are radially aligned with respect to the first axis X and extend between the orifices 292 and 294 of the disks 236 and 238.

[0074] The number of concave curved sections 298a and 299a and convex portions 298b and 299b of the circumferential edges 298 and 299 of disks 236 and 238 is equal to the number of orifices 292 and 294 of the disk. This means that the number of concave curved sections 298a on edge 298 is equal to the number of convex curved sections 298b on that edge, and also equals the number of orifices 292 and 294 of the disk. Similarly, the number of concave curved sections 299a on edge 299 is equal to the number of convex curved sections 299b on that edge, and also equals the number of orifices 292 and 294 of the disk.

[0075] Figure 7 and Figure 8 The following characteristics are shown.

[0076] The convex curved section 298b of the inner peripheral edge 298 can extend around the second axis Y of the apertures 292 and 294 of the disk.

[0077] The angular range α of the convex curved section 298b of the inner peripheral edge 298 around the first axis X can be smaller than the angular range β of the concave curved section 298a of the inner peripheral edge 298 around the first axis X.

[0078] The angle range γ of the concave curved section 299a of the outer peripheral edge 299 around the first axis X can be less than or equal to the angle range δ of the convex curved section 299b of the outer peripheral edge 299 around the first axis X.

[0079] α can be the same as γ, but differ by + / -30%, preferably + / -10%.

[0080] β can be the same as δ, but differ by + / -30%, preferably + / -10%.

[0081] The top of the convex curved section 298b of the inner peripheral edge 298 may be located on a circumference C1 with a first diameter D1 centered on the first axis X.

[0082] All the concave curved sections 298a of the inner peripheral edge 298 can be located entirely on the circumference C1.

[0083] The top of the concave curved section 298a of the inner peripheral edge 298 may be located on another circumference C2 with a second diameter C2 centered on the first axis X.

[0084] Half the difference between the second diameter D2 and the first diameter D1 can be less than or equal to the minimum radial thickness E1 of the material surrounding the orifices 292, 294 of the disk at the level of the inner peripheral edge 298. The thickness of this material, or the strip-like structure of the material, is preferably reduced to the minimum value required for the mechanical strength of the corresponding bearing receiving orifice.

[0085] The top of the concave curved section 299a of the outer peripheral edge 299 may be located on a circumference C3 with a first diameter D3 centered on the first axis X.

[0086] All the convex curved sections 299b of the outer peripheral edge 299 can be located entirely on the circumference C3.

[0087] The top of the convex curved section 299b of the outer peripheral edge 299 is located on another circumference C4 with a second diameter D4 centered on the first axis X.

[0088] Half the difference between the second diameter D3 and the first diameter D4 can be greater than or equal to the minimum radial thickness E2 of the material surrounding the orifices 292 and 294 of the disks 236 and 238 at the level of the outer peripheral edge 299.

[0089] The radius of curvature X1 of the convex curved section 298b of the inner peripheral edge 298 can be smaller than the radius of curvature of the concave curved section 298b of the inner peripheral edge 298 (which corresponds to D2 / 2).

[0090] The radius of curvature X2 of the concave curved section 299a of the outer peripheral edge 299 can be strictly smaller than the radius of curvature of the convex curved section 299b of the outer peripheral edge 299 (which corresponds to D4 / 2).

[0091] The maximum radial dimension H1 of the planet carrier 213 at the level of the orifices 292 and 294 of disks 236 and 238 can be smaller than the maximum radial dimension H2 of the planet carrier 213 located between orifices 292 and 294. Figure 7 ).

[0092] Figure 9 and Figure 10A second embodiment of the planetary carrier 313 according to the present invention is shown. The planetary carrier 313 may be an integral planetary carrier, or it may have a cage 320 and a cage bracket.

[0093] In these and subsequent figures, the elements already described above are represented by adding one hundred more to the same labels.

[0094] In these diagrams, planetary carrier 313 includes: - A first disc 336 extends centered on and perpendicular to axis X. The first disc 336 includes first apertures 392 centered on axis Y, which is parallel to and arranged around axis X. - A second disc 338, centered on axis X, parallel to disc 336 and located at a certain distance from disc 336, includes second orifices 394 centered on axis Y, the number of second orifices 394 being equal to the number of first orifices 392, and... - Bridge connector 396, which extends between and connects disks 336 and 338 together, and these bridge connectors 396 are integrated with disks 336 and 338.

[0095] In the diagram, one of the two disks 236 and 238 can be seen. However, due to the similarity between the two disks 336 and 338, the two disks 336 and 338 can have the same characteristics.

[0096] Referring to the position of the reduction gear in the turbine engine and the gas flow in the turbine engine, the first disc 336 is, for example, the front disc or the upstream disc, and the second disc 338 is, for example, the rear disc or the downstream disc.

[0097] Orifices 392 and 394 are used to mount planetary gears, particularly planetary gear guide bearings, in the planet carrier 313. The bearings include longitudinal ends received within these orifices 392 and 394. For example, the bearings can be sliding bearings (hydrodynamic bearings) or rolling bearings. These bearings are not shown in the figures.

[0098] At least one of the disks 336 and 338 has orifices 392 and 394 arranged in pairs. These pairs are virtual pairs; in this application, the concept of a pair of disks defines the presence of two orifices that are side-by-side or circumferentially adjacent. For example, reference numeral B refers to a pair. The number of orifice pairs in disks 336 and 338 is equal to N-1, where N is the number of orifices 392 and 394 in the disks.

[0099] Therefore, each pair of orifices 392 or 394 includes two orifices that are circumferentially adjacent.

[0100] Discs 336, 338, or each disc 336, 338, include a first through hole 400 located between each pair of orifices 392 or 394, the first through hole 400 intersecting a first plane P1 and a second plane P2, the first plane P1 extending radially relative to a first axis X and located at a distance equidistant from the pair of orifices 392 or 394, the second plane P2 passing through a second axis Y of these orifices.

[0101] Advantageously, the first plane P1 is the first plane of symmetry of the hole 400. The first plane P1 can also be the plane of symmetry of the opening 380a.

[0102] The second plane P2 can also be the symmetric plane of hole 400.

[0103] Figures 10 to 13 Several variations of the hole 400 are shown.

[0104] exist Figure 10 In the case, each hole 400 includes a radially inner edge 400a that is convexly curved around a first axis X, a radially outer edge 400b that is concavely curved around the first axis X, a first lateral edge 400c that is convexly curved around the second axis Y of the first hole in the pair of holes 392 or 394, and a second lateral edge 400d that is convexly curved around the second axis Y of the second hole in the pair of holes 392 or 394.

[0105] exist Figure 11 In the middle, each hole 400 has a circular elliptical shape, including a larger lateral dimension U1 extending along the first plane P1.

[0106] exist Figure 12 In the middle, each hole 400 has a rectangular shape with rounded corners.

[0107] exist Figure 13 In the middle, each hole 400 has a circular shape centered on the intersection point or line W between the first plane P1 and the second plane P2.

[0108] If possible Figure 13 As seen in the alternative shown, disks 336, 338 or each disk 336, 338 may include at least one additional through hole 401, 402 located between each pair of orifices 392, 394, the at least one additional through hole 401, 402 being radially located above or below the first hole 400 and intersecting the first plane P1.

[0109] The first hole 400 and the additional holes 400a, 400b, or each of the additional holes 400a, 400b, have the same shape and size.

[0110] As can be seen in the accompanying drawings, disks 336, 338 or each disk 336, 338 may include at least one through opening 380a located between each pair of orifices 392, 394, and the first plane P1 is also the plane of symmetry of the opening 380a.

[0111] Discs 336, 338 or each disc 336, 338 have a material thickness Z1 measured in a radial direction relative to a first axis X between the inner peripheral edge 398 of the disc and the first hole 400. Preferably, the material thickness Z1 is less than a second material thickness Z2 measured in the same direction between the first hole 400 and the opening 380a.

[0112] This invention offers many advantages, including reducing the local stiffness of the planetary carrier, which in turn reduces the overload mentioned above, as well as the total mass of the planetary carrier and the reduction gear.

Claims

1. A planetary carrier (213, 313) for a mechanical reduction gear (10, 110) in an aircraft turbine engine (1), the planetary carrier (213, 313) comprising: - A first disc (236, 336) extends about and perpendicular to a central axis (X), the first disc (236, 336) including first bearing orifices (292, 392) centered on bearing axes (Y), the bearing axes being circumferentially distributed around and parallel to the central axis (X). - A second bearing plate (238, 338), which extends axially away from the first bearing plate (236, 336) and centered on the central axis (X). This second bearing plate (238, 338) includes second bearing orifices (294, 394) centered on the bearing axis (Y), respectively. The number of second bearing orifices (294, 394) is equal to the number of first bearing orifices (292, 392). - A bridge connector (296, 396) that extends between the first and second discs (236, 238, 336, 338) and connects the first and second discs together. The planetary carrier is characterized in that: - At least one of the disks (236, 238, 336, 338) includes alternating concave curved sections (298a, 299a) and convex curved sections (298b, 299b) on each of the inner and outer peripheral edges (298, 299) of the disk (236, 238, 336, 338), wherein the convex curved section (298b) of the inner peripheral edge (298) and the concave curved section (299a) of the outer peripheral edge (299) are radially aligned with respect to the central axis (X) and respectively on the disk (236, 238) The bearing orifices (292, 294) of the disk (236, 238) extend radially inward and radially outward, the concave curved section (298a) of the inner peripheral edge (298) and the convex curved section (299b) of the outer peripheral edge (299) are radially aligned with respect to the central axis (X), and the number of concave and convex curved sections (298a, 298b, 299, 299b) of the inner and outer peripheral edges (298, 299) of the disk (236, 238) is equal to the number of bearing orifices (292, 294) of the disk (236, 238). And / or: - Bearing bores (392, 394) of at least one of the disks (336, 338) are distributed in pairs, each pair of bearing bores (392, 394) comprising two circumferentially adjacent bearing bores (392, 394), the disk or each disk (336, 338) comprising a pair of bearing bores (392, 394), the pair of bearing bores comprising a first through hole (400) located between the bearing bores (392, 394) in each pair of bearing bores (392, 394), the first through hole intersecting a first plane (P1) and a second plane (P2), the first plane extending radially relative to the central axis (X) and located at a distance equidistant from the pair of bearing bores (392, 394), the second plane passing through the bearing axis (Y) of the pair of bearing bores (392, 394), the first plane (P1) being a first plane of symmetry of the hole (400).

2. The planetary carrier (213) according to claim 1, wherein, The convex curved section (298b) of the inner peripheral edge (298) extends around the bearing axis (Y) of the bearing bore (292, 294) of the disk (236, 238).

3. The planetary carrier (213) according to claim 1 or 2, wherein, The angular range (α) of the convex curved section (298b) of the inner peripheral edge (298) around the central axis (X) is smaller than the angular range (β) of the concave curved section (299a) of the inner peripheral edge (299) around the central axis. And / or: - The angle range (y) of the concave curved section (299a) of the outer peripheral edge (299) around the central axis (X) is less than or equal to the angle range (d) of the convex curved section (299b) of the outer peripheral edge (299) around the central axis.

4. The planetary carrier (213) according to any one of claims 1 to 3, wherein, The angular range (α) of the convex curved section (298b) of the inner peripheral edge (298) around the central axis (X) is equal to + / -10% of the angular range (ψ) of the concave curved section (299a) of the outer peripheral edge (299) around the central axis (X), and / or, the angular range (β) of the concave curved section (298a) of the inner peripheral edge (298) around the central axis (X) is equal to + / -10% of the angular range (δ) of the convex curved section (299b) of the outer peripheral edge (299) around the central axis (X).

5. The planetary carrier (213) according to any one of claims 1 to 4, wherein: - The top of the convex curved section (298b) of the inner peripheral edge (298) lies on a circumference (C1) with a first diameter (D1) centered on the central axis (C1), and the top of the concave curved section (298a) of the inner peripheral edge (298) lies on another circumference (C2) with a second diameter (D2) centered on the central axis (X), wherein the difference between the second diameter and the first diameter (D1, D2) is less than or equal to the minimum radial thickness (E1) of the material of the disk (236, 238) surrounding the bearing orifice (292, 294) of the disk at the level of the outer peripheral edge (298). And / or: - The top of the concave curved section (299a) of the outer peripheral edge (299) is located on a circumference (C3) with a third diameter (D3) centered on the central axis (X), and the top of the convex curved section (299b) of the outer peripheral edge (299) is located on another circumference (C2) with a second diameter (D4) centered on the central axis (X), the difference between the second diameter and the first diameter (D3, D4) being greater than or equal to the minimum radial thickness (E2) of the material of the disk (236, 238) surrounding the bearing orifice (392, 394) of the disk at the level of the outer peripheral edge (299).

6. The planetary carrier (313) according to any one of the preceding claims, wherein, The second plane (P2) is also the plane of symmetry of the hole (400).

7. The planetary carrier (313) according to any one of the preceding claims, wherein, The disc or each disc (336, 338) including the pair of bearing bores (392, 394) includes at least one additional through hole (401, 402) circumferentially located between each pair of bearing bores (392, 394), the at least one additional through hole being radially located above or below the first hole (400) and intersecting the first plane (P1).

8. The planetary carrier (313) according to claim 7, wherein, The first hole (400) and the additional holes or each additional hole (401, 402) have the same shape and size.

9. The planetary carrier (313) according to any one of the preceding claims, wherein, The disk or each disk (336, 338) including the pair of bearing bores (392, 394) includes at least one through opening (380a) circumferentially located between each pair of bearing bores (392, 394), and the first plane (P1) is also the plane of symmetry of the opening (380a).

10. The planetary carrier (313) according to claim 9, wherein, The disk or each disk (336, 338) has a material thickness (Z1) measured in a radial direction relative to the central axis (X) between the inner peripheral edge of the disk (336, 338) and the first hole (400), the material thickness (Z1) being less than a second material thickness (Z2) measured in the same direction between the first hole (400) and the opening (380a).

11. A mechanical reduction gear (10, 110) for an aircraft turbine engine, comprising a planetary carrier (213, 313) according to any one of the preceding claims, said reduction gear further comprising: - A sun gear (11), which is centered on the central axis (X) and mounted between disks (236, 238, 336, 338) of the planet carrier (213, 313). - A planetary gear (12), which is centered on the bearing axis (Y) and mounted between disks (236, 238, 336, 338) of the planet carrier (213, 313), and is guided to rotate by bearings (8) respectively housed in the first and second bearing holes (292, 294, 392, 394) of the disks (236, 238, 336, 338), and - Ring gear (14), which extends around the central axis (X) and around the sun gear (11) and the planetary gear (12), the planetary gear (12) meshing with the sun gear (11) and the ring gear (14).

12. A turbine engine (1), particularly a turbine engine for an aircraft, comprising a reduction gear (10, 110) according to claim 11.

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