Platform for fan assemblies

Abstract

The present invention relates to a platform (6) for a fan assembly (1), the platform comprising a flow channel wall (8) extending in an axial direction having an upstream end and a downstream end, and the platform comprising two axial reinforcements (10). The platform (6) includes radial retaining devices (16, 18, 20, 22) arranged at the upstream and downstream ends of the flow channel wall (8), the radial retaining devices (16, 18, 20, 22) being designed to each define a sliding connection with a corresponding shroud of the fan assembly (1), and the platform includes tangential retaining devices designed to define a sliding pivot connection between a disc (2) of the fan assembly (1) and the platform (6).

Description

Technical Field

[0001] This invention relates to the field of platforms with impellers. Background Technology

[0002] In a known manner, such as Figure 1 As schematically shown, a low-pressure compressor may consist of a bladed impeller X for a fan, the fan including a housing, a fan disk I, multiple blades and their retaining system, multiple platforms III, and an upstream shroud IV.

[0003] In a known manner, the platform is an integral part with an impeller for the fan, which constitutes the first moving wheel stage. The platform must ensure the following functions:

[0004] • Key aerodynamic functions:

[0005] -Limited airflow channels.

[0006] • Meets all operating conditions:

[0007] - Ensure the performance of the entire flight envelope.

[0008] - To ensure safety requirements,

[0009] - Ensure the engine is suitable for commercial use.

[0010] • Integrated into the engine environment:

[0011] - It has an interface that matches the boundaries of the moving wheel level.

[0012] - Avoid interference in other stages of the low-pressure compressor.

[0013] More precisely, performance and integration requirements are reflected in a good seal near the blade root, which is held within the disc. This seal is directly controlled by the platform's ability to connect with the blade near the blade root, and at all operating points. At a certain clearance, a seal can be used to fill the gap. Above a certain clearance, a seal is difficult to ensure.

[0014] Furthermore, performance and integration requirements are also reflected in the ability to reduce the hub-to-displacement ratio. The lower the ratio, the greater the increase in flow rate and the better the fan performance. This reduction in hub-to-displacement ratio prevents the integration of so-called "box-type" platforms known in the prior art. These platforms, in practice, have a box-like structure that provides the necessary rigidity to support an acceptable degree of movement and mechanical stress. The platform is held upstream and downstream, for example, corresponding to a shroud; the upstream end of the platform may include generally radial lugs attached to the disk or to an intermediate component connected to the disk by bolts (based on the principles taught in reference, for example, FR-2 992 676). Reference FR-3 029 563 proposes a key for locking the box-like structure relative to the disk. This attachment method is very stable but results in a particularly large platform, leading to a high hub-to-displacement ratio.

[0015] Therefore, many existing technologies attempt to resolve the conflict between optimal platform attachment and achieving a low hub ratio. For example, reference can be made to US20140186187, which describes a platform with improved upstream attachment to maintain a low hub ratio.

[0016] However, there are currently two main solutions for attaching the platform to the disk while maintaining a low hub-to-disk ratio. According to the first solution, the platform is screwed to the radial extension of the disk (as described in document US 20140186187). According to the other solution, the platform is held in place by multiple hooks carried by the disk.

[0017] These known solutions are particularly limiting. More specifically, the multiplicity of the screw or hook leads to certain assembly kinematics, which typically involve rotating the platform about a rotational axis and then moving it axially to engage the platform with the hook. However, this axial movement affects the previously described gaps, creating gaps that are difficult to fill with seals.

[0018] In this case, it is necessary to provide a platform that can be easily attached to the disc, has a low hub-to-blade ratio, ensures sufficient clearance to the blade, and allows for controlled sealing of the connection to the blade root. Summary of the Invention

[0019] According to a first aspect, the present invention provides a platform with an impeller, the platform including a flow channel wall extending in an axial direction having an upstream end and a downstream end, and the platform including two axial reinforcements. The platform includes radial retaining devices disposed at the upstream and downstream ends of the flow channel wall, the radial retaining devices being adapted to each define a sliding connection with a corresponding shroud of the impeller, and the platform includes tangential retaining devices adapted to define a sliding pivot connection between the impeller disc and the platform.

[0020] The tangential retaining device may include a pin and a lug, the lug having a bore adapted to receive the pin, such that the assembly including the lug and the pin forms a sliding pivot connection.

[0021] Lugs can be attached to flow channels, and pins can be adapted to be attached to discs with impellers.

[0022] The radial retaining device includes an upstream circumferential land portion and a downstream circumferential land portion, which are adapted to engage in corresponding upstream and downstream guards with impellers, respectively.

[0023] The flow channels and reinforcements can be made of composite materials.

[0024] According to a second aspect, the present invention relates to an assembly of a disc and a platform with a blade wheel, wherein the disc receives the platform and the disc has a fitting in which a pin is attached, the pin being adapted to engage in a lug of the platform by a sliding pivot connection.

[0025] The disk can receive a platform and may include at least one downstream shield suitable for receiving downstream circumferential land and at least one upstream shield suitable for receiving upstream circumferential land.

[0026] According to another aspect, the present invention relates to a turbine comprising at least one component according to the invention.

[0027] According to another aspect, the present invention relates to an aircraft comprising at least one turbine according to the invention. Attached Figure Description

[0028] Other features, objects, and advantages of the invention will become apparent from the following description, which is given only in an illustrative and non-limiting manner and should be read with reference to the accompanying drawings, in which:

[0029] - Figure 1 This is a schematic diagram of a bladed impeller in existing technology;

[0030] - Figure 2 This is a perspective view of the components including a disk and a platform according to the present invention.

[0031] - Figure 3 This is a detailed perspective view of an assembly including an upstream circumferential land section and an upstream shield according to the present invention.

[0032] - Figure 4 This is a detailed perspective view of an assembly including a downstream circumferential land portion and a downstream shield according to the present invention.

[0033] - Figure 5This is a detailed perspective view of the assembly including the lugs and pins of the platform according to the present invention.

[0034] - Figure 6 yes Figure 5 A partial cross-sectional perspective view of the component including lugs and pins.

[0035] - Figure 7 This is a schematic perspective view of the platform according to the present invention.

[0036] - Figure 8 This is a schematic diagram of the connection between the pin and the lug according to the second embodiment of the present invention. Detailed Implementation

[0037] Background with impeller

[0038] The present invention is located in the impeller 1 of a fan. Typically, this fan is a low-pressure compressor fan.

[0039] The impeller 1 includes a disk 2, to which blades 4 are attached. A platform 6 is located at the interface between the blades 4 and the disk 2, specifically to form a flow near the root of the blades in the flow channel between the blades via the upper surface of the platform, the root of the blades being held in the disk and held in a conventional recess of the disk.

[0040] As will be described below, the present invention relates to platform 6 and disk 2, and more specifically, to the connection between platform 6 and disk 2.

[0041] platform

[0042] According to a first aspect, the present invention proposes a platform 6 with a blade wheel 1.

[0043] Specifically, refer to Figure 2 The platform 6 according to the invention includes a flow channel wall 8 extending in the axial direction. The flow channel wall 8 has a so-called upper surface opposite the disk, which defines a surface shape that facilitates fluid flow between the blades in the overall longitudinal direction within the flow channel. In this case, the flow channel wall 8 extends in the axial direction between the upstream region and the flow channel wall 8, which facilitates air flow in the fan between the upstream and downstream sides of the impeller 1.

[0044] In a particularly advantageous manner, the flow channel wall 8 is made of a composite material. This choice of material allows for a flow channel wall 8 with optimal curvature. In fact, choosing a flow channel wall 8 made of a composite material allows the flow channel 8 to be shaped according to the desired surface geometry (unlike metal plates, which are more difficult to shape). Furthermore, in the case of blades made of composite materials, the flow channel wall made of composite materials results in less aggression relative to the blade in the event of a significant impact.

[0045] Furthermore, platform 6 includes two axial reinforcements 10. The reinforcements 10 are located below the wall of the flow channel 8 to reinforce the wall. The term "bottom surface" refers to the location of the reinforcements 10 between the disk 2 and the flow channel wall 8 when platform 6 is attached to disk 2. Therefore, airflow can pass through the flow channel wall 8 without being disturbed by the reinforcements 10. In other words, the structure of platform 6, with the flow channel 8 reinforced by the axial reinforcements 10, advantageously enables it to have a mechanically resistive structure that provides an optimal surface for airflow.

[0046] Preferably, the reinforcing part 10 can be made of composite material.

[0047] In a particularly advantageous manner, platform 6 includes radial retaining devices and tangential retaining devices.

[0048] Radial retaining device

[0049] In particular, such as Figure 2 As shown, radial retaining devices are located upstream 12 and downstream 14 of platform 6.

[0050] Typically, platform 6 includes a radial retaining device disposed upstream 12 and a radial retaining device disposed downstream 14.

[0051] like Figure 3 As shown, preferably, the radial holding device includes an upstream circumferential land portion 16 located at the upstream end 12 of the platform 6.

[0052] The term "circumferential rib" refers to the circumferential rib, which is in the shape of a circular arc.

[0053] like Figure 3As shown and described below, the upstream circumferential land portion 16 is adapted to engage in a circumferential groove in the upstream shroud 18. Preferably, the connection between the upstream circumferential land portion 16 and the upstream shroud 18 is a sliding connection. Therefore, by positioning in the reference frame with the impeller 1 in the axial, radial, and tangential directions, the connection between the upstream circumferential land portion 16 and the upstream shroud 18 restricts rotational freedom and prevents translational movement in the radial direction. In contrast, translational movement in the axial direction is permitted. This allows the upstream circumferential land portion 16 to be introduced into the upstream shroud 18 and removed from the upstream shroud when assembly or disassembly is required via the upstream shroud (which is removed in this example). The upstream shroud axially holds the upstream side of the platform to block the platform in that direction. Furthermore, translational movement in the tangential direction is permitted.

[0054] like Figure 4 As shown, preferably, the radial holding device includes a downstream circumferential land portion 20 located at the downstream end 14 of the platform.

[0055] The term "circumferential rib" refers to the circumferential rib, which is in the shape of a circular arc.

[0056] like Figure 4 As shown and described below, the downstream circumferential land portion 20 is adapted to engage in a circumferential groove in the downstream shroud 22. Preferably, the connection between the downstream circumferential land portion 20 and the downstream shroud 22 is a sliding connection. Therefore, by positioning in the reference frame with the impeller 1 in the axial, radial, and tangential directions, the connection between the downstream circumferential land portion 20 and the downstream shroud 22 restricts rotational freedom and prevents translational movement in the radial direction. The downstream shroud axially holds the downstream side of the platform to block the platform in that direction. In contrast, translational movement in the axial direction is allowed on the downstream side when the upstream shroud is removed for assembly and disassembly operations. In this case, it is possible to introduce the downstream circumferential land portion 20 into the downstream shroud 22 and to remove the downstream circumferential land portion from the downstream shroud. Furthermore, translational movement in the tangential direction is permitted.

[0057] Assembly and manufacturing of the flow channel walls made of composite materials through circumferential land section assembly and manufacturing enables a very low hub-to-hub ratio while minimizing the mass of the impeller.

[0058] Tangential holding device

[0059] Platform 6 also includes a tangential holding device.

[0060] Preferably, the tangential retaining device is adapted to define a sliding pivotal connection between the disc 2 with the blade wheel 1 and the platform 6.

[0061] Reference Figure 2 , Figure 5 , Figure 6 and Figure 8 The tangential retaining device includes a lug 26 and a pin 28. The lug 26 has a drilled hole adapted to receive the pin 28, and thus forms a sliding pivot connection with the pin 28.

[0062] Preferably, the lug 26 is attached to the flow channel wall 8, and the pin 28 is attached to the disc 2.

[0063] Lug 26 can be made of metal and is screwed to the bottom surface of the flow channel wall 8.

[0064] Lug 26 has an attachment portion 26a attached to the flow channel wall 8 of platform 6 and a connecting portion 26b with a drilled hole 30 connected to the disk, the latter intended to connect with assembly 36. The attachment portion intersects with the portion with the drilled hole 30. More specifically, refer to... Figure 5 The attachment portion 26a includes a hook plate 27a, which is designed to be clamped and screwed onto the flow channel wall 8. Typically, the hook plate 27a can be screwed onto the flow channel wall 8 using two screws 81. Furthermore, the attachment portion 26a includes two semi-circular sides 27b. These semi-circular sides mechanically reinforce the connection between the attachment portion 26a and the connecting portion 26b. The term "semi-circular" is intended to indicate that each side 27b has a curved edge that forms a continuous and progressive connection with the connecting portion 26b. This arrangement allows for optimization of the mechanical strength of the lug 26, particularly by maximizing the resistance to bending forces between the attachment portion 26a and the connecting portion 26b.

[0065] As will be detailed below, the sliding pivot connection is a particularly advantageous arrangement of the invention, which ensures blocking in the tangential direction while allowing movement in the axial direction. This arrangement is particularly interesting, for example, in the event of an impact on the impeller 1 (e.g., caused by a bird).

[0066] plate

[0067] According to another aspect, the present invention provides a disc 2 for a blade wheel 1, which is adapted to cooperate with a platform 6 according to the present invention.

[0068] The disc 2 according to the invention has a plurality of supports 36, each adapted to receive a pin 28, and the supports 36 are radially protruding portions. The term "assembly" 36 is intended to refer to a metal lug or tongue that extends in the radial direction and has a drilled hole 30 adapted to receive the pin 28.

[0069] The fitting 36 has an adjacent surface that connects to the connecting portion 26b of the lug 26.

[0070] According to Figure 5 and Figure 6In the first embodiment shown, the abutting surface of the fitting 36 faces the abutting surface of the connecting portion 26b, and these two abutting surfaces are located in a radial plane. In other words, according to this first embodiment, the abutting surfaces of the fitting 36 and the connecting portion 26b are located in a plane substantially perpendicular to the axial rotation direction of the disc 2 and the impeller 1. According to this embodiment, the attachment portion 26a of the lug 26 and the connecting portion 26b having the drilled hole 30 intersect at an angle substantially different from 90 degrees, and this angle is defined according to the desired inclination of the flow channel 8.

[0071] according to Figure 8 In the second embodiment shown, the two adjacent surfaces of the fitting 36 and the connecting portion 26b lie in a plane inclined relative to the radial plane. In other words, according to this second embodiment, the adjacent surfaces are not located in a plane substantially perpendicular to the axial rotation direction of the disc 2 and the impeller 1. According to this embodiment, the attachment portion 26a of the lug 26 intersects the connecting portion 26b having the drilled hole 30 at an angle of approximately 90 degrees (orthogonal). This second embodiment has the advantage of being easier to assemble. In fact, the orthogonal lug 26 facilitates the introduction of a tool that can screw the lug 26 onto the flow channel wall 8.

[0072] Furthermore, in either embodiment, pin 28 is attached to assembly 36. Preferably, the pin is connected to the assembly via an interlocking connection, meaning all degrees of freedom of pin 28 are blocked.

[0073] Preferably, pin 28 is screwed onto assembly 36, such as... Figure 5 and Figure 6 As shown.

[0074] characteristic

[0075] Compared to systems with multiple pins, using a single pin 28 with a sliding pivot connection to engage with the circumferential land section has the advantage of easy assembly, while maintaining a stable system for absorbing mechanical forces and positioning the platform.

[0076] Furthermore, in the event of bird ingestion-type impact, the system, which is connected to the circumferential land section via a single pin 28 in a sliding pivotal connection, frees up degrees of freedom compared to a system with multiple pins, and simplifies the arrangement of the platform 6 to avoid the risk of damage to the platform 6 during assembly and operation.

[0077] Therefore, by releasing these degrees of freedom while maintaining the main function of pin 28 (i.e., absorbing centrifugal force), the installation of platform 6 is made easier.

[0078] More specifically, on the one hand, the longitudinal positioning of the assembly 36 approximately at the middle length of the disc and the longitudinal positioning of the lug 26 approximately at the middle length of the platform reduce the risk of deformation of the platform 6 under the centrifugal force experienced by the platform 6 during operation.

[0079] Furthermore, the installation of the platform 6 according to the invention has a shorter assembly kinematics compared to prior art platforms, which reduces the necessary clearance and thus strengthens the mechanical structure connecting the platform 6 and the disk 2. It should be noted that the necessary clearance is directly related to the displacement required during assembly and disassembly. In the case of the invention, the assembly / disassembly kinematics are reduced, and therefore the clearance is correspondingly reduced.

[0080] Finally, the use of a single pin 28 for each platform 6 enables the formation of a lighter system (i.e., lighter than existing systems with multiple pins), which is particularly advantageous in aerospace environments where weight management is a critical issue.

[0081] In addition, such as Figure 7 As illustrated, maintenance (i.e., removal) of platform 6 is particularly easy. It is sufficient to combine translational movement to disengage the pin, and then rotational movement about the axial direction to disengage the circumferential land.

[0082] Components

[0083] According to another aspect, the present invention relates to an assembly comprising a disc 2 according to the invention for a bladed wheel 1 and a platform 6 according to the invention, wherein the disc 2 receives the platform 6.

[0084] turbine

[0085] According to another aspect, the present invention relates to a turbine comprising at least one component according to the invention.

[0086] aircraft

[0087] According to another aspect, the present invention relates to an aircraft comprising at least one turbine according to the invention.

Claims

1. A platform (6) for a bladed impeller (1), the platform comprising: - A flow channel wall (8) extending in the axial direction, the flow channel wall having an upstream end and a downstream end, and including two axial reinforcements (10). -Radial retaining devices (16, 18, 20, 22) arranged at the upstream and downstream ends of the flow channel wall (8), the radial retaining devices (16, 18, 20, 22) being designed to each define a sliding connection with a corresponding shroud of the impeller (1), - Tangential retaining device, which is designed to define a sliding connection between the disc (2) with the blade wheel (1) and the platform (6); The sliding connection has a rotation axis parallel to the axial direction. The platform (6) and the disc (2) with the blade wheel (1) are slidably connected along the axial direction.

2. The platform (6) according to claim 1, wherein, The tangential retaining device (28, 26, 30) includes a pin (28) and a lug (26) having a drilled hole (30) adapted to receive the pin (28) such that the assembly of the lug (26) and the pin (28) forms a sliding pivot connection.

3. The platform (6) according to claim 2, wherein, The lug (26) is attached to the flow channel wall (8), and the pin (28) is adapted to be attached to the disc (2) with the impeller (1).

4. The platform (6) according to claim 1, wherein, The radial retaining device (16, 18, 20, 22) includes an upstream circumferential land portion (16) and a downstream circumferential land portion (20), which are adapted to engage in corresponding upstream and downstream guards (18 and 22) of the bladed impeller (1), respectively.

5. The platform (6) according to claim 1, wherein, The flow channel wall (8) and the reinforcing part (10) are made of composite material.

6. An assembly comprising a blade wheel (1) and a platform (6) according to claim 3, wherein, The disc (2) receives the platform (6), and the disc has a fitting (36) in which a pin (28) is attached, the pin being adapted to engage in a lug (26) of the platform by means of a sliding pivot connection.

7. An assembly comprising a blade wheel (1) and a platform (6) according to claim 4, wherein, The disk (2) receives the platform (6) and includes at least one downstream shield (22) adapted to receive the downstream circumferential land portion (20) and at least one upstream shield (18) adapted to receive the upstream circumferential land portion (16).

8. A turbine comprising at least one component according to claim 7.

9. An aircraft comprising at least one turbine according to claim 8.

Images