Turbine engine having a pair of propellers for an aircraft

Abstract

An engine includes systems for changing the pitch of propeller blades, a system for an upstream propeller including a linear actuator and a transmission mechanism connecting the actuator to the blades to transform the sliding of the actuator into a rotation of the blades, the upstream propeller including a rotatable housing rigidly connected to a rotatable shaft supported in a static housing of the turbine engine by an upstream bearing and by a downstream bearing. The rotatable housing of the upstream propeller includes a support rigidly connected to the rotatable housing and surrounding the static housing. The actuator is annular and fixed outside to the support, the transfer mechanism includes connecting rods and rotatable radial arms traversing the gaseous flow path, and the downstream bearing is radially located between the static housing and the support.

Claims

1. A turbine engine having a pair of contrarotating upstream and downstream coaxial propellers for an aircraft, including respective systems for changing a pitch of blades of the propellers, the system for the upstream propeller including a linear hydraulic actuator, a sliding movable part of which is movable along an axis of the propeller, a transmission mechanism connecting the actuator to the blades in order to transform sliding of the actuator into a rotation of the blades about axes thereof, and a rotatable housing rigidly connected to a shaft for driving in rotation said rotatable housing being supported in a static housing of the turbine engine by a bearing upstream of the system, and by a bearing downstream of the system, wherein: the rotatable housing of the upstream propeller includes a support receiving the linear actuator and rigidly connected to said rotatable housing and surrounding a cylindrical end part of the static housing, the linear hydraulic actuator of the system for changing pitch is annular and comprises a fixed part directly mounted to the support of the rotatable housing so as to be joined axially and in rotation thereto, outside the support, and the sliding part being joined to the transmission mechanism, said actuator being fixed in rotation with the rotatable housing, a piston of the linear hydraulic actuator is rigidly connected to the fixed part, said transmission mechanism of the system comprising connecting rods connected at first ends by first bail joints to the sliding movable part and at second ends by second ball joints to rotatable radial arms radially traversing a gaseous flow path in order to control the pitch of the blades, and the downstream bearing is radially located between the static housing and the support.

2. The turbine engine according to claim 1, wherein the downstream bearing, which is provided between the static housing and the support, is mounted inside the support.

3. The turbine engine according to claim 2, wherein the support includes a cylindrical plate, of annular cross-section, attached to or rigidly connected to the rotatable housing of the upstream propeller and extending laterally from said rotatable housing and surrounding the cylindrical end part of the static housing in the direction of the downstream bearing.

4. The turbine engine according to claim 1, wherein a pivot point of the blades is situated above the linear actuator.

5. The turbine engine according to claim 1, wherein a fluid supply device of the actuator is provided between the static housing and the support of the upstream propeller, and wherein said support bears said actuator.

6. The turbine engine according to claim 5, wherein the fluid supply device and the downstream bearing are arranged side by side between the static housing, and an interior of the support, the fluid supply device being vertically above the linear actuator, the downstream bearing being adjacent to the fluid supply device and being located between said actuator and the rotatable housing of the upstream propeller, the actuator being mounted by a fixed part thereof on an exterior of the support.

7. The turbine engine according to claim 5, wherein the fluid supply device comprises an internal cylindrical part rigidly connected to the static housing, and an external cylindrical part arranged concentrically with the internal cylindrical part and rigidly connected to the support, two independent chambers being formed between the internal cylindrical part and the external cylindrical part by sealing means, said chambers being connected, for the internal cylindrical part, to fluid supply lines and, for the external cylindrical part, to respective chambers of the actuator.

8. The turbine engine according to claim 7, wherein the fluid supply lines run along an interior of the static housing as far as the cylindrical end part thereof and communicate with the chambers of the fluid supply device.

9. The turbine engine according to claim 7, wherein said internal and external cylindrical parts are in axial abutment against respective shoulders of the static housing and of the support, and axially immobilized by respective clamping nuts.

10. The turbine engine according to claim 7, wherein the sealing means between the internal and external cylindrical parts delimiting the two chambers adjacent to the fluid supply device comprise composite double dynamic sealing joints.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) The figures of the appended drawings will enable a good understanding of how the invention can be carried out. In these drawings, identical reference numerals designate similar elements.

(2) FIG. 1 is a schematic view, in longitudinal section, of a turbine engine having a pair of contrarotating propellers, such as an open rotor turboshaft engine described above.

(3) FIG. 2 is a partial schematic view in longitudinal section of the turboshaft engine described above and shows the arrangement according to the prior art between the rotatable housing of the upstream propeller, the static housing, the system for changing the pitch and the bearings for mounting between the static housing and the rotatable housing.

(4) FIG. 3 is a partial schematic view in longitudinal section of the turboshaft engine described above and shows the arrangement according to the invention between the rotatable housing of the upstream propeller, the static housing, the system for changing the pitch and the bearings for mounting between the static housing and the propeller.

(5) FIG. 4 shows an enlarged and longitudinal schematic view in longitudinal section of the oil supply device of the actuator of the system for changing pitch, from the static housing of the turbine engine.

DETAILED DESCRIPTION OF THE INVENTION

(6) The representation illustrated with regard to FIG. 3 shows, radially from the axis A, the internal drive shaft 18 of the rotatable housing of the downstream propeller, the external drive shaft 17 of the rotatable housing 19 of the upstream propeller 2 with the inter-shaft bearing 31 on the reduction gear side, and the static structural housing 27 enclosing the external shaft 17 with the upstream bearing 29, such as a thrust ball bearing, arranged therebetween.

(7) According to the invention, a support 36, which is situated around the cylindrical end part 37 of the static structural housing 27 and spaced radially from this part, projects laterally from the rotatable housing 19 of the upstream propeller. This support 37 is intended to receive the annular linear actuator 23 of the system for changing pitch 22 in order to render the actuator rotatable and independent of the static housing and thus to enable the forces which it generates during its operation to no longer pass through the upstream bearing 29 between the static and rotatable housings of the embodiment according to FIG. 2.

(8) In the embodiment illustrated schematically with regard to FIG. 3, the support 36 takes the form of a cylindrical plate or sheet 38 of annular cross-section which may form an integral part of the rotatable housing or may be attached thereto by any appropriate fixing means (assembly by screws and the like, welding, etc.). The panel 38 is metallic and extends laterally along the axis A, from the rotatable housing 19 in the direction of the downstream bearing 30 and of the system 22, and it surrounds the cylindrical part 37 of the static housing 27 over a sufficient length in order to support the actuator 23.

(9) This linear actuator 23 is an annular actuator of the hydraulic type with the fixed part 26 thereof which is mounted on the exterior surface of the plate 38 forming the support 36, being joined there axially and in rotation by any appropriate means. The sliding part (or movable body) 28 of the actuator is itself joined to the transmission mechanism 24 having connecting rods 33 and radial arms 34 of the system 22, and the rotation of the arms via themselves, as a result of the sliding of the actuator and of the connecting rods, transmits the rotation of the pivot axes 25 of the blades. The annular linear actuator 23 is therefore fixed in rotation with the rotatable housing of the upstream propeller.

(10) In the representation illustrated with regard to FIGS. 3 and 4, the fixed part 26 and the sliding part 28 of the actuator mutually delimit, by means of a piston 39 rigidly connected to the fixed part, two adjacent and sealed chambers 40, 41.

(11) The absence of the transfer bearing 32 of the preceding embodiment will be noted, since the linear actuator 23 is rigidly connected to the rotatable housing. Joints 42 then connect the sliding part 28 to one of the ends of the connecting rods 33. Joints 65 connect the other end of the connecting rods to the radial arms 34 which are mounted in radial bearings 66 of the rotatable housing, situated within the gas flow path F.

(12) During the operation of the system 22, the action of the connecting rods 33 driven by the sliding actuator directly transmits the rotation of the radial arms 34 via themselves into the bearings 66, within the annular gas flow path F circulating in the turbine engine. The rotatable radial arms pass through the flow path and transmit their rotation to the pivot axes 25 of the blades housed, in the usual manner, in a polygonal ring (not shown) arranged at the periphery of the external housing of the propeller 2, outside the gas flow path.

(13) The downstream roller bearing 30 is located between the annular plate 38 and the cylindrical end part 37 of the static housing 27. The internal ring 43 of said bearing is mounted at the end of the part 37 of the static housing and the external ring 44 co-operates by being retained axially there, with the internal surface of the annular plate 38 forming the support 36 of the rotatable housing.

(14) In order to enable the supply of oil to the actuator 23, which is then rotatable, by the fluid source (not shown), and which is rigidly connected to the static housing 27 of which the supply/discharge lines are shown schematically at 45, 46 by broken lines, a supply device 47 with changing of markers is provided. This device 47 is designed in order to ensure the passage of the oil originating from the source and the lines 45, 46 of the static housing 27 (fixed marker) to the linear actuator 23 of the rotatable housing 19 (movable marker).

(15) As shown in FIG. 3 and in greater detail in FIG. 4, the supply device 47 is arranged in the annular space between the plate 38 of the support 36 and the cylindrical end part 37 terminating the static housing 27, and is vertically above the annular actuator 23. It will be noted in FIG. 3 that the supply device 47 and the downstream bearing 30 are arranged side by side between the rotatable plate 38 and the static housing 27, together with the roller bearing 30 which is situated between the device 47 and the rotatable housing 19 of the upstream propeller 2. In addition to the compactness thus obtained, it will be noted that the plate of the support has the length necessary for mounting on the outside of the actuator and on the inside of the bearing and of the device, which also reduces the path of the force loop B1 as shown on FIG. 3.

(16) According to the illustrated example, the oil supply device 47 comprises an assembly of two concentric cylindrical parts 48, 49 which delimit therebetween two sealed adjacent chambers 50, 51 communicating respectively with the lines 45, 46 and the corresponding adjacent chambers 40, 41 of the actuator 23.

(17) In particular, the cylindrical part 48 is internal and is mounted around the cylindrical end part 37 of the static housing 27, being in axial abutment against an external annular shoulder 52 of the part 37, and being immobilised, in opposition to the abutment, by a clamping nut 53 screwed to the end of the part 37. The cylindrical part 49 is external and is mounted inside the plate 38 of the rotatable housing, being in axial abutment against an internal annular shoulder 54 of the plate 38, and being immobilised in opposition by a clamping nut 55 screwed into the plate.

(18) Between the two cylindrical parts 48, 49 thus mounted are defined the two annular adjacent chambers 50, 51 delimited by three radial collars 56 formed, in this example, from the internal part 48.

(19) Holes 57 are made in the wall of the internal part 48. They are in fluid communication, on the one hand, with orifices 58 made in the cylindrical part 37 of the static housing and to which the respective supply lines 45, 46 are connected, and on the other hand, with the chambers 50, 51 of the device 47.

(20) Holes 59 are also made in the wall of the external part 49. They are in fluid communication on the one hand with the chambers 50, 51 and on the other hand with orifices 60 made in the support plate 38 and communicating with the respective chambers 40, 41 of the actuator 23. It will be noted in FIG. 4 that the plate 38 of the rotatable support and the fixed part 26 of the actuator are represented by the same part. Of course, the orifices 60 pass through the walls of the plate 38 and that of the fixed part 26 in order to open into the corresponding chambers of the actuator.

(21) It will also be noted that the lines 45, 46 coming from the source run along inside the static housing 27 (FIG. 3) as far as the end part 37 thereof, between said end part and the drive shaft 17, which makes it possible to protect them from the external environment having the system 22 and the rotatable housing 19.

(22) Sealing means 61 are provided between the fixed internal cylindrical part 48 and the rotatable external cylindrical part 49 in order to enable the changing of markers between said internal and external parts and, therefore, the fluid supply of the chambers of the device 47 and of the actuator 23.

(23) These means 61 are defined by dynamic seals accommodated in annular grooves 62 provided in the three collars 56 of the internal part 48, and coming into contact with the wall of the external part 49.

(24) In particular, the dynamic seals are double and composite. They are each composed of a first sealing element 63 in the form of a pretensioned O ring made of elastomer which is accommodated in the groove 62 of the collar 56, and around said collar, of a second external element 64 in the form of a more rigid ring. Said ring has appropriate properties of friction and of resistance to wear in order to guarantee maximum sealing during the rotation of the external part 49 rigidly connected to the rotatable housing 19 with respect to the internal part 48 rigidly connected to the static housing 27. Each ring 64 is, for example, produced partially or entirely from polytetrafluoroethylene.

(25) Functionally, when the system 22 for changing the pitch of the blades 2A of the upstream propeller 2 is biased according to the current flight phase, one or the other of the chambers 40, 41 of the annular actuator 23 is supplied with oil under pressure by the corresponding chamber 50, 51 of the supply device 47 and drives the sliding, along the axis A, of the movable part 28 of the actuator. Simultaneously, the connecting rods 33 of the transmission mechanism 24 which are articulated to the sliding part 28 are pulled or pushed and, via the respective joints 65, impose a rotation on the radial arms 34, which leads directly to the concomitant rotation of the pivot axes 25 of the blades 2A of the upstream propeller 2 orienting the blades according to the setting required.

(26) As the linear actuator 23 is rigidly connected to the rotatable housing 19 of the upstream propeller by the support 36 having a plate 38, the forces generated by the sliding of the movable part 28 pass through the rotatable housing 19 of the upstream propeller, without passing through the static housing 27 or through the upstream bearing 29, as shown by the loop B1 in FIG. 3. This loop B1 coming from the sliding part 28 of the actuator passes through the connecting rods 33 and the rotatable radial arms 34 of the mechanism 24, the rotatable housing 19 having its support 36, via the axially fixed external ring 44 of the downstream roller bearing 30, and the fixed part 26 of the actuator.

(27) Thus no force passes through the static housing 27 and the upstream bearing 29, so that said bearing is not overloaded by forces other than those for which it is designed, by virtue of the actuator 23 rigidly connected to the rotatable housing 19 and of the supply device for changing of markers 47 between the static housing 27 of the turboshaft engine and the rotatable housing 19 of the upstream propeller 2.