TURBINE GEAR BUILT IN A HOUSING

1. Technical Field of the Invention

The invention relates to turbine engines for aircraft, particularly Recessed turbine in a reduction gearbox, such as a power transmission unit.

2. BACKGROUND

A gas turbine engine comprises in known manner a gas generator and a turbine mounted on a shaft, said power shaft extending along one direction, said longitudinal direction. This power shaft is configured to be mechanically connected to a gearbox housing. The gear housing is, for example, in the case of a helicopter, a power transmission box connected to the (x) rotor (s) of the helicopter. When the power turbine shaft and the gear housing are mechanically coupled, the power of the power shaft is transmitted to the power transmission box, thereby rotating the (s) the rotor (s ) of the helicopter.

The turbine power shaft is in turn driven in rotation by the turbine which receives the gases produced by the gas generator and that relaxes, which allows to transform the kinetic energy of gas received in a recovered mechanical energy by the power shaft.

The turbine can be a free turbine of the gas generator or a gas turbine generator-related. Throughout the text, the invention is described in connection with a free turbine. However, the invention also applies to a turbine engine comprising a turbine connected to the gas generator.

The power shaft therefore comprises two ends, one end, said end of power, which is configured to be connected to the gearbox housing, and an opposite end, said free end, which typically carries the blades of the free turbine. The power end is usually reported to the front of the turbine engine at the gearbox housing and is therefore also known as the end words before. This is called before assembly of the turbine engine to the gear box.

The inventors have sought to design a turbine engine that can be easily mounted on a reduction gearbox and removed therefrom, eg for maintenance. The inventors have particularly sought to provide a solution to connect the power end of the power shaft to a gearbox housing.

3. Objectives of the invention

The invention aims to provide, in at least one embodiment of the invention, a turbine engine that can be easily mounted on a gearbox housing, such as a power transmission gearbox.

The invention also aims to provide, in at least one embodiment of the invention, a gas turbine engine which contributes to limit the axial size of the assembly formed of the turbine engine and the housing when the turbine engine is mounted on the gear housing.

The invention also aims to provide, in at least one embodiment of the invention, a gas turbine engine which contributes to limit the mass of the assembly formed of the turbine engine and the housing when the turbine engine is mounted on the gear housing.

The invention also aims to provide, in at least one embodiment, an aircraft, especially a helicopter, equipped with at least one turbine engine according to the invention.

4. Summary of the Invention

To do this, the invention relates to a helicopter turbine engine comprising a housing in which is arranged a gas generator and a power turbine mounted on a shaft extending along a longitudinal direction and said reversible engagement means power shaft in a gearbox housing in which is arranged at least one gear wheel 1 of a first reduction stage, said reversible embedding means including a pinion having a central bore shaped to said shaft power so that said pinion can be fitted on said power shaft, said pinion also having a periphery shaped to said gear wheel of the 1 stfloor so that it can form an input of the drive gear meshed housing in said gear wheel, once said recessed power shaft in said gear housing.

A turbine engine according to the invention is equipped with reversible engagement means of the power shaft in a gearbox housing. These reversible engagement means of the power shaft in a reduction gearbox form a turbine engine installation kit on a reduction gearbox, that is to say they confer to the engine which they are associated, functionality be directly embedded on a reducing and separate housing of the latter. Throughout the text, we therefore refers to these installation means also by the terms "flush mount kit" to highlight that although the embedding means form the mounting connection between the turbine engine and the gearbox housing. A turbine engine according to the invention is built directly on a gearbox housing such that it can be easily connected to the gearbox housing when necessary, and separated from the latter, for example for maintenance on the turbine engine. Such a turbine engine built according to the invention is configured to be directly connected to the gear housing and be maintained by the reduction gearbox. The embedding of the turbine engine to the gear unit housing may be a vertical installation, horizontal or oblique. This feature allows a significant weight saving on the overall drive train of the aircraft. In particular, a turbine engine equipped with engagement means enables an offset level in the power shaft directly in the gear unit housing and thus a limitation of the axial length of the turbine engine, these bearings supporting the output shaft only when the turbine engine is embedded in the gear housing. The embedding kit formed by the engagement means comprises a pinion gear configured to be fitted on the power shaft. The fitting of the gear on the free turbine shaft is for example obtained by a splined connection. This connection may, alternatively, be locked by a nut which secures the gear on the free turbine of the power shaft and which opposes longitudinal movement of the pinion along the power shaft. Once fitted and fixed pinion on the power shaft, the

fitted can be moved in the gear housing. The pinion is configured such that once mounted in the gear housing, it can engage the gear wheel of the gear unit housing and thus form the input drive gear of the gear unit housing.

Advantageously and according to the invention, the reversible embedding means further comprises a rear bearing of the pinion, and a front bearing pinion each for heating the assembly formed of said pinion fitted on said power shaft when said power shaft embedded in said housing respectively in the vicinity of a housing inlet and adjacent a longitudinally housing base opposite said inlet housing, each front and rear bearing further including rolling elements, an inner ring to be centered bearing against the pinion and an outer ring to be centered in abutment against the gear housing.

According to this variant, the installation kit further comprises front and rear bearings of the pinion for carrying the power of the power shaft end directly in the gear housing and to allow its rotation. In other words, the levels of the power shaft are part of the installation kit and are set to be deported in the gear housing. These bearings are formed by bearings of the pinion forming the drive pinion of the one first reduction stage of the reducer housing, once the recessed power shaft on the gear housing.

Advantageously and according to a variant of the invention, the rear bearing of said pinion is integral with said housing, said rolling elements and the inner race of said front bearing are mounted on said power shaft, and said outer race of said front bearing is configured to be be housed in said gear housing and secured to said gear housing before the embedding of said power shaft in said gear housing.

According to this variant, the rear bearing of the drive pinion is integral with the turbine housing and the inner and outer rings of the front bearing are well qu'appariées with each other, separated from each other: the ring inner and the rolling elements of the front bearing mounted on the turbine engine output shaft, while the outer ring of the front bearing is fixed on the gear housing. The outer ring may for example be mounted in the gear housing prior to movement of the assembly formed of the power shaft, the pinion fitted on the output shaft, the rear bearing, the outer ring and rolling elements the front bearing, integral with the turbine housing. In other words, the front bearing is reconstituted only when fitted the turbine engine in the gear housing. The inner ring is then housed facing the outer ring pre-mounted in the gearbox housing.

Advantageously and according to another variant of the invention, said reversible embedding means comprises a cage door bearings adapted to be connected integrally to said housing of the turbine engine, said cage integrally carrying said front and rear bearings of said front sprocket, and said cage being shaped to come to bear against at least two centering portions formed in said limp reducer.

In this embodiment, the front and rear bearings of the pinion are carried by a cage door bearings. In other words, unlike the previous embodiment, both the front bearing and the rear bearing are integral with the casing of the turbine engine, through the cage door bearings. This cage is further configured to be able to cooperate with locating portions provided in the gear housing.

Advantageously and according to this embodiment, the cage comprises at least one radial flat in which is formed an opening through which may extend a peripheral portion of the pinion to ensure the meshing of said pinion meshing with said wheel of the 1 st floor.

The opening in a flat part extending radially ensures mechanical connection between the sprocket mount kit forming the pinion housing inlet and leading the engaging sprocket 1 st reduction stage. Furthermore, this flat avoids interference with the wheel of the 1 st stage of the turbine engine during installation operations in the gear housing and in the disassembly of the turbine engine reduction gearbox.

Advantageously and according to the invention, the gear housing is a power transmission box. The power transmission gearbox is connected to the (x) rotor (s) of the helicopter. When the power turbine shaft and the power transmission box are mechanically coupled, the power of the power shaft is transmitted to the power transmission box, thereby rotating the (s) rotor (s) of the helicopter.

The invention also relates to a helicopter comprising at least one turbine engine according to the invention.

The invention also relates to a turbine engine and a helicopter equipped with a turbine engine, characterized in combination by all or some of the features mentioned above or below.

5. List of Figures

Other objects, features and advantages of the invention will appear on reading the following description given by way of non-limiting and which refers to the appended figures in which:

- Figure 1 is a schematic sectional view of a gas turbine engine according to an embodiment of the invention,

- Figure 2 is a partial schematic side view of a turbine engine according to an embodiment of the invention,

- Figure 3 is a partial schematic side view of a turbine engine according to another embodiment of the invention,

- Figure 4 is a schematic sectional view of a detail of the gas turbine engine according to the embodiment of Figure 2,

- Figure 5 is a schematic sectional view of a detail of the gas turbine engine according to the embodiment of Figure 3,

- Figure 6 is a schematic perspective view of a cage door bearings of a gas turbine engine according to the embodiment of Figures 3 and 5,

- Figure 7 is a schematic perspective view of the cage door bearing of Figure 6 in mechanical interaction with a gear wheel of a 1 st stage of reduction of a reduction gearbox.

6. Detailed description of embodiments of the invention

In the figures, scales and proportions are not strictly complied with, for purposes of illustration and clarity. Throughout the following detailed description with reference to the figures, unless otherwise indicated, each element of the turbine engine is described as it is arranged when the turbine engine is in horizontal mounting position, built on a reduction gearbox. This arrangement is particularly shown in Figure 1. Furthermore, the terms "axial", "longitudinal", "front" and "rear" refer to locations along the central axis X'X of the turbine engine. Specifically, throughout the text and in connection with Figures 1 and 3, the front of the turbine engine is the left part of FIGS while the rear part is on the right. In connection with Figures 4 and 5, the before the turbine engine is lower and the rear part is the upper part. The term "radial" refers to locations perpendicular to this central axis. Finally, the elements having the same reference symbols in different figures refer to like elements or elements with a similar function.

As shown in Figure 1, a gas turbine engine according to the invention comprises a housing 5 in which are mounted a gas generator and a free turbine 6 7. The free turbine 7 is integral with a power shaft 8. According to the embodiment of the figures, the 8 power shaft which carries the free turbine 7 and which connects the turbine engine to a gearbox housing 10, passes inside the gas generator shaft so that end 9 of the power of the power shaft is on the side of the gas generator. The gas generator 6 and its operation are described in detail and are well known in the art. The invention applies of course also to a gas turbine engine whose power shaft does not pass through the gas generator and whose power end is at the opposite of the gas generator. In other words, the invention applies both to mount front or rear mounting of a turbine engine of a reduction gearbox.

A turbine engine according to the invention further comprises reversible engagement means 8 of the power shaft in a 10-gear housing

wherein is arranged at least one wheel 11 of a gear 1 st reduction stage. This gear wheel 11 is shown in Figures 4 and 5. It may include all types of gear comprising a serrated periphery adapted to be rotated by a driving gear. The reduction gearbox 10 includes, for example, and as shown in Figures 4 and 5, an upper housing 10a and a lower housing 10b fixed to each other by fixing means of the screw-nut type.

The reversible engagement means 8 of the power shaft 10 in the gear housing form an installation kit. This embedding kit is formed of a plurality of parts that are described below, and which when assembled to each other and / or secured either to the casing of the turbine engine or the gearbox housing, enable the embedding of the turbine engine in the gear housing.

This embedding kit comprises a pinion 12 having a central bore of consistent shapes and dimensions and combined with the circumference of the 8 power shaft. For example, the central bore of the pinion 8 is splined hex shaped periphery to the hexagon of the power shaft. This allows fixing in rotation the pinion 12 to the power shaft 8, once the pinion fitted on the output shaft 8. According to the embodiment of the figures and as shown in Figures 3 and 4, the embedding kit further includes a nut 13 mounted around the end 8 of the power shaft for longitudinally locking the pinion 12 fitted on 8 the power shaft. The pinion 12 is fitted onto the power shaft 8 prior to the displacement of the

The embedding kit further comprises a rear bearing 15 gear, and a bearing 16 before gear. The rear bearing 15 gear is arranged, once the power shaft 8 recessed in the 10 off housing in the vicinity of the entrance of the housing 10 to reduce. 16 before pinion bearing is arranged, once the power shaft 8 embedded in the housing 10 off, in the vicinity of a bottom housing 20 longitudinally opposed to the housing inlet.

The rear bearing 15 includes bearing elements 22, a ring 23

inner, centered bearing against the pinion 12, when the turbine engine built in the gear housing, and an outer ring 24 centered in abutment against the top cover 10a of the casing 10 reducing once the turbine engine built in the gear housing.

The bearing 16 before comprises 25 rolling elements, a 26 inner ring centered in abutment against the pinion 12, once the recessed turbine engine in the gear housing, and an outer 27 ring centered in abutment against the lower case 10b of the gear housing, once flush gas turbine engine in the gear housing.

According to the embodiment of Figures 2 and 4, the rear bearing 15 is secured to the casing 5 of the turbine engine and the elements 25 and the ring bearing

26 of the inner bearing 16 are mounted on the front 8 of shaft power. The ring

27 of the outer bearing 16 before is secured to the lower housing 10b of the housing 10 to reduce. The outer ring 27 of bearing 16 is mounted and secured before the reducer housing 10 before the descent of the shaft 8 on which the power sprocket 12 is fitted and on which are mounted the inner ring 26 and the elements 25 of rolling bearing 16 before. The diameter of the outer ring 27 is selected such that it can pass into a bore 10a of the upper housing of the gear housing. The width of the outer ring 27 is selected so that it passes between the lower face of the wheel gear 11 1 streduction stage and the underside of the lower casing 10b of the gear housing in order to be housed in the lower casing 10b of the gear housing. According to another variant, the outer ring 27 can be mounted in the gear housing from the bottom of the housing, that is to say by the bottom 10b of the casing 10 reduction gearbox. A gas turbine engine according to this embodiment allows its installation in a reduction gearbox. Maintaining the power shaft 8 is obtained by forming the front and rear bearings described in connection with Figures 2 and 4.

According to another embodiment and as described in connection with Figures 3 and 5, the engagement means 8 of the power shaft in the gear unit housing comprises a cage 30 carries bearings. This cage is secured to the casing 5 of the turbine engine, for example by means of the screw-nut type 51. The

cage 30 carries bearings integrally supports the bearing 16 and the front bearing 15 of the rear sprocket 12. The cage 30 also has a periphery shaped to portions 53a, 53b centering 10a formed respectively in the upper casing and the lower casing 10b of the housing 10 discount. Thus, once mounted integrally on the housing 5 of the turbine engine, the assembly formed by the 8 power shaft and the cage 30 can be installed in the gear housing and the cage bears against the portions 53a, 53b centering . The 8 power shaft is then held in the gear housing.

The cage 30 further comprises a radial flat 56 wherein there is an opening 57 allowing the passage of the pinion 12 and its engagement with the wheel 11 of the one first reduction stage. This connection between the pinion 12 and the wheel 11 through the opening 57 of the cage 30 is shown schematically in Figure 7. In Figure 7, only the lower portion of the pinion 12 is visible. The crenellated portion of the pinion 12 complied with the wheel 11 meshing extends inside the cage 30 carries bearings.

In Figures 4 and 5, the assembly formed by the 8 power shaft, the pinion 12 fitted over the 8 power shaft and bearings integral elements of the shaft or the housing (30 per cage mode embodiment of Figure 5; rear bearing 15, rolling element and inner ring of the front bearing for the embodiment of Figure 4) and is displaced in the gear housing 10 to ensure the embedding is schematically delimited by the dotted lines 60 .

CLAIMS

1. A gas turbine engine for a helicopter comprising a housing (5) in which is arranged a generator (6) and a gas turbine (7) mounted on a shaft (8) power extending along a direction (X'X ) longitudinally, characterized in that it comprises reversible engagement means of said shaft (8) power in a housing (10) reducing wherein is arranged at least one wheel (11) of a gear 1 st floor reduction and in that said reversible embedding means comprises a pinion (12) having a central bore shaped to said shaft (8) power so that said pinion (12) can be fitted on said shaft (8) power, said pinion (12) further having a periphery shaped to said wheel (11) gear 1 stfloor so that it can form an input of the drive gear meshed housing in said gear wheel, when said shaft (8) recessed in said power box (10) gearbox.

2. A gas turbine engine for a helicopter according to claim 1 characterized in that said reversible embedding means further comprises a bearing (15) rear sprocket, and a bearing (16) each forward gear for carrying the assembly formed of said pinion (12) fitted on said shaft (8) of power after said recessed power shaft in said housing (10) gear respectively adjacent a housing inlet and in the vicinity of a bottom (20) of longitudinally opposite housing said inlet of the housing, each bearing (16) before and (15) behind further comprising elements (25, 22) bearing a ring (26, 23) interior to be centered in abutment against the pinion (12) and a ring (27, 24) external to be centered against the bearing housing (10) gearbox.

3. A gas turbine engine for a helicopter according to claim 2, characterized in that said bearing (15) of said rear sprocket (12) is integral with said housing (5), said elements (25) and bearing ring (26) inside said bearing ( 16) are mounted on the front shaft (8) of power, and said ring (27) of said outer bearing (16) before is configured to be housed in said housing (10) gear and fixed to said reducer housing front underrun said shaft (8) power into said housing (10) gearbox.

4. A gas turbine engine for a helicopter according to claim 2, characterized in that said reversible embedding means comprises a cage (30) carries bearings adapted to be fixedly connected to said housing (5) of the turbine engine, said cage (30) integrally supporting said bearing (16) forward and said bearing (15) rearwardly of said pinion (12) before, and said cage (30) being shaped to abut against at least two portions (53a, 53b) for centering provided in said housing (10) reducer.

5. A gas turbine engine for a helicopter according to claim 4, characterized in that said cage (30) comprises at least one flat (56) radial in which is formed an opening (57) through which may extend a peripheral portion of the pinion ( 12) for the meshing of said pinion (12) with said wheel (11) meshing the 1 st floor.

6. A gas turbine engine for a helicopter according to one of claims 1 to 5, characterized in that the gear housing is a power transmission box.

7. Helicopter comprising at least one turbine engine according to one of claims 1 to 6.