CN209781044U - Fan rotor support system - Google Patents

Abstract

An object of the utility model is to provide a fan rotor braced system, support the awl wall including the bearing for to connect fan rotor's bearing support in intermediary machine casket, the bearing supports the awl wall and includes: a first conical wall section, an upstream end of which is connected to a bearing; a second tapered wall section, the downstream end of which is connected to an intermediate casing; a fusing member connecting a downstream end of the first tapered wall section and an upstream end of the second tapered wall section and configured to fuse at a predetermined load; and a resilient member connecting a downstream end of the first conical wall section and an upstream end of the second conical wall section. The fan rotor support system can improve the safety of the aircraft engine.

Description

Fan rotor support system

Technical Field

The utility model relates to a fan rotor braced system.

Background

During the operation of an aircraft engine, one or more fan blades may be detached (FBO) due to unavoidable reasons such as foreign object ingestion, fatigue, and the like. FBO events can cause significant shock and unbalance loading of the fan rotor. Such fan blade out events require airworthiness certification to ensure flight safety, as required by airworthiness regulations (FAR33.74, FAR 33.94).

The traditional method is to increase the structural strength of each part on the force transmission path of the engine, such as a rotor support structure, a bearing casing, a mounting system and the like, so that the engine has higher stress margin reserve to deal with FBO (fiber bulk acoustic resonator) load. However, this results in an increase in the weight of the engine, which is disadvantageous in improving the operating efficiency of the engine.

Another countermeasure is to use a fused design with a deactivatable component located near the bearing supporting the rotor, e.g., the # 1 bearing closest to the fan. By a deactivatable component is meant a mechanically weak structure capable of failing under a predetermined load (fusing threshold). After the FBO event occurs, a fusing component near the 1# bearing is failed, the critical rotating speed of the low-pressure rotor is reduced and is far less than the working rotating speed, so that the low-pressure rotor is in a supercritical state, the orbit motion radius is reduced, and the input unbalanced load is reduced; on the other hand, the fusing component fails to change the transmission path of the FBO load to the stator casing, so that the FBO load is redistributed, and the safety of the engine is effectively protected.

However, the current common fusing designs, such as thinned sections (see patent US6447248), radial bolts (see patent US7318685), etc., all cause the bearing supporting conical wall structure of the # 1 bearing to completely break after the FBO event occurs, releasing the support and constraint of the low pressure rotor at the # 1 bearing to change the force transmission path, reduce the support stiffness, and reduce the FBO load transmitted to critical components.

The above-described fused design, however, results in the low voltage rotor completely losing support and restraint at the # 1 bearing. The low-voltage rotor completely loses the constraint at the No. 1 bearing, the swing radius of the fan can be increased, the low-voltage rotor can move around the fan shaft at will and generate friction and scratch with the fan shaft, the fan shaft is damaged, and for titanium alloy fan blades, the blades excessively collide with a casing and even a fire disaster can be caused; and the low-pressure shaft is easy to generate bending stress concentration at the 2# bearing. Since the engine also needs to last long, sometimes perhaps as long as 180 minutes, during the windmilling period after the FBO event occurs, damage to the fan shaft may affect the safety of the engine under continued rotation.

In addition, for the three-pivot rotor structure and the double-pivot rotor structure of the 1# bearing, the complete loss of the support of the 1# bearing can cause the axial constraint of the rotating shaft to be lost, possibly causing the flying-off of the low-pressure rotor and causing catastrophic results.

Accordingly, there is a need for a fan rotor support system that can increase aircraft engine safety after an FBO event occurs.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a fan rotor braced system can improve aeroengine's security.

The utility model provides a fan rotor braced system, support the awl wall including the bearing for to connect fan rotor's bearing support in intermediary machine casket, the bearing supports the awl wall and includes: a first conical wall section, an upstream end of which is connected to a bearing; a second tapered wall section, the downstream end of which is connected to an intermediate casing; a fusing member connecting a downstream end of the first tapered wall section and an upstream end of the second tapered wall section and configured to fuse at a predetermined load; and a resilient member connecting a downstream end of the first conical wall section and an upstream end of the second conical wall section.

In one embodiment, the fusing member and the elastic member connect the first tapered wall section and the second tapered wall section in a radial direction of the fan rotor.

In one embodiment, the fusing member and the elastic member are spaced apart by a predetermined distance in an axial direction of the fan rotor.

In one embodiment, the fusing member is located on a downstream side of the elastic member.

In one embodiment, the upstream end of the second conical wall section is terminated around the outer circumference of the downstream end of the first conical wall section.

In one embodiment, the axial length of the first conical wall section in the axial direction of the fan rotor is smaller than the axial length of the second conical wall section.

In one embodiment, the fusing member is a rigid member provided with a weak portion.

In one embodiment, the weak portion of the rigid member is a reduced thickness portion of the rigid member.

in one embodiment, the resilient member is comprised of a superelastic shape memory alloy wire damper.

In one embodiment, the first conical wall section and the second conical wall section are disposed in parallel, and the fusing member and the elastic member are disposed perpendicular to the first conical wall section, in a cross section taken along a central axis of the fan rotor.

In the fan rotor supporting system, the force transmission path between the fan rotor and the intermediate casing can be decoupled after an FBO event occurs through failure of the fusing part, so that the supporting rigidity of the bearing is reduced, the peak load of the FBO is reduced, the design difficulty of an engine part system is reduced, and the weight reduction design of an engine is facilitated. And through using elastomeric element for can provide certain axial and radial support between two sections around bearing support conical wall after fusing part became invalid, avoid cracked bearing support conical wall and fan axle to take place to bump and rub. After the fuse member is fused, energy can be absorbed by the elastic member to reduce the load transmitted to the intermediate case, in addition to providing partial support. Thus, the above-described fan rotor support system provides a fusing design that reduces the support stiffness at the bearings, reduces the loads transmitted from the fan rotor to critical engine components, and provides some radial and axial restraint.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings:

FIG. 1 is an exemplary configuration of a turbofan engine interior in which a fan rotor support system according to the present invention is employed;

FIG. 2 is an example configuration of a fan rotor support system.

Fig. 3 is a partially enlarged view of the area indicated by a in fig. 2.

Detailed Description

The present invention will be further described with reference to the following detailed description and the accompanying drawings, wherein the following description sets forth more details for the purpose of providing a thorough understanding of the present invention, but it is obvious that the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar generalizations and deductions based on the practical application without departing from the spirit of the present invention, and therefore, the scope of the present invention should not be limited by the contents of the detailed description.

For example, a first feature described later in the specification may be formed over or on a second feature, and may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. Additionally, reference numerals and/or letters may be repeated in the various examples throughout this disclosure. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Further, when a first element is described as being coupled or coupled to a second element, the description includes embodiments in which the first and second elements are directly coupled or coupled to each other, as well as embodiments in which one or more additional intervening elements are added to indirectly couple or couple the first and second elements to each other.

as used herein, the terms "a", "an" and/or "the" are not to be construed as limiting the singular, but rather are intended to include the plural unless the context clearly dictates otherwise. In general, the terms "comprises" and "comprising" merely indicate that steps and elements are included which are explicitly identified, that the steps and elements do not form an exclusive list, and that a method or apparatus may include other steps or elements.

For convenience in description, spatial relational terms such as "below," "beneath," "below," "under," "over," "upper," and the like may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that these terms of spatial relationship are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary words "below" and "beneath" can encompass both an orientation of up and down. The device may have other orientations (rotated 90 degrees or at other orientations) and the spatial relationship descriptors used herein should be interpreted accordingly. Further, it will also be understood that when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.

It should be noted that these and other figures are given by way of example only and are not drawn to scale, and should not be construed as limiting the scope of the invention as it is actually claimed. Further, the conversion methods in the different embodiments may be appropriately combined.

As an example of an aircraft engine, a turbofan engine may include a high and low pressure dual rotor system. For example, the low pressure rotor may be supported by a # 1 bearing, a # 2 bearing, and a # 5 bearing, wherein the # 1 bearing may be a ball bearing, and the # 2 bearing and the # 5 bearing may be a rolling rod bearing. The following description will be given taking a low-pressure rotor as an example, and only the support structures of the bearing # 1 and the bearing # 2 are shown.

As shown in fig. 1, the turbofan engine 100 includes a fan rotor 20, a fan case 7, and an intermediate case 4 connected to the fan case 7. In fig. 1, gas is fed from the left side and discharged from the right side. It is to be understood that the central axis L1 of the turbofan engine 100 or the fan rotor 20 is shown, and the overall structure may be rotationally symmetric about the central axis L1, i.e., the overall structure may be a solid structure that is rotated about the central axis L1 by the configuration shown in fig. 1. The sections shown in fig. 1 and later fig. 2 and 3 may all be referred to as cross-sections taken along the central axis L1 of the fan rotor 20.

Hereinafter, for convenience of description, a direction parallel to the central axis L1 of the fan rotor 20 is referred to as an axial direction, a direction along the radial direction of the fan rotor 20 is referred to as a radial direction, and a direction along the circumferential direction of the fan rotor 20 is referred to as a circumferential direction.

The terms "along a predetermined direction" and "in a predetermined direction" include directions having a component in the predetermined direction, that is, the directions may be inclined with respect to the predetermined direction but may not be perpendicular to each other. "parallel" may refer to exact parallel where the intersection angle between two directions is zero, or may refer to approximate parallel where the intersection angle between two directions is within a certain range, for example, within 10 degrees, and "perpendicular" may refer to exact perpendicular where the intersection angle between two directions is 90 degrees, or may refer to approximate perpendicular where the intersection angle between two directions is within a certain range, for example, within 10 degrees, from 90 degrees.

Also, the terms "upstream," "front," "downstream," or "rear" are used hereinafter with respect to the intake direction of the engine, with "upstream" or "front" being closer to the intake end of the engine and "downstream" or "rear" being closer to the exhaust end of the engine.

the fan rotor 20, which includes the fan shaft 2 and the fan blades 3 mounted to the fan shaft 2, is located inside the fan case 7 and surrounded by the fan case 7. Turbofan engine 100 further comprises a fan rotor support system 1, the fan shaft 2 of fan rotor 20 being connected to an intermediate case 4 by means of fan rotor support system 1, fan rotor support system 1 typically comprising a forward end bearing 5 and an aft end bearing 6, i.e. fan shaft 2 is supported to intermediate case 4 by means of forward end bearing 5 and aft end bearing 6, such that fan shaft 2 of fan rotor 20 is rotatable relative to intermediate case 4, thereby rotating fan blades 3 mounted on fan shaft 2. The front end bearing 5 may also be referred to as a # 1 bearing, for example a roller bearing may be used to provide radial constraint to the fan shaft 2. The rear end bearing 6 may also be referred to as a # 2 bearing, for example a ball bearing may be used, providing both axial and radial constraint to the fan shaft 2.

Referring to fig. 2, the fan rotor support system 1 further includes a bearing support cone wall 10. In the illustrated embodiment, the bearing support cone wall 10 extends in a radial direction, and the bearing support cone wall 10 may support a front end bearing 5, which is connected to the fan rotor 20 (specifically, the fan shaft 2), to the intermediate casing 4.

The bearing support cone wall 10 according to the present invention comprises a first cone wall section 11 and a second cone wall section 12. The upstream end of the first conical wall section 11 (in fig. 2, the lower left end of the first conical wall section 11) is connected to the front end bearing 5, and the downstream end of the second conical wall section 12 (in fig. 2, the upper right end of the second conical wall section 12) is connected to the intermediate casing 4. For example, the first conical wall section 11 and the second conical wall section 12 may be thin-walled annular structures constituting a conical cylinder shape, which is small in diameter near the front end of the turbofan engine 100 and large in diameter near the rear end of the turbofan engine 100.

In the illustrated embodiment, the first conical wall section 11 and the second conical wall section 12 are arranged in parallel, that is, the conical cylinder of the first conical wall section 11 and the conical cylinder of the second conical wall section 12 are both centered on the central axis L1 and have substantially the same taper.

Further, the upstream end of the second taper wall section 12 is surrounded on the outer peripheral side of the downstream end of the first taper wall section 11. That is, the second cone wall section 12 is located radially outside the first cone wall section 11, or the radial dimension of the cone cylinder constituted by the second cone wall section 12 is larger than the radial dimension of the cone cylinder constituted by the first cone wall section 11, and the upstream end of the second cone wall section 12 and the downstream end of the first cone wall section 11 partially overlap in the radial direction.

the bearing support cone wall 10 further comprises a load shedding mechanism 13. The load shedding mechanism 13 connects the downstream end of the first conical wall section 11 (in fig. 2, the upper right end of the first conical wall section 11) and the upstream end of the second conical wall section 12 (in fig. 2, the lower left end of the second conical wall section 12).

Referring to fig. 3, fig. 3 shows a partially enlarged view of the load lowering mechanism 13 in the circle indicated by a in fig. 2.

The load descending mechanism 13 includes a fusing member 14 and an elastic member 15. The fusing member 14 and the elastic member 15 each connect the downstream end of the first tapered wall section 11 and the upstream end of the second tapered wall section 13. Wherein the fusing part 14 may be fused under a predetermined load.

For example, the fusing member 14 may be a rigid member provided with the weak portion 141. The rigid member as the fusing member 14 can completely restrain the relative degree of freedom between the front and rear sections of the bearing support cone wall 10, that is, the first cone wall section 11 and the second cone wall section 12.

In the illustrated embodiment, the weak portion 141 of the rigid member as the fusing member 14 is a thinned portion of the rigid member, that is, the weak portion 141 of the fusing member 14 is thinned to realize a weakening effect. In fact, the weakened portion 141 may be any structural form with weak structural strength, for example, the weakened portion 141 of the fusing element 14 may be implemented by using a material with lower strength. The weak portions 141 may be distributed continuously or discontinuously in the circumferential direction as long as the condition for causing the fusing element 14 to fuse and fail under the FBO load is satisfied.

The elastic member 15 has elasticity, and may be formed of, for example, a superelastic shape-memory alloy wire damper, and is elastically deformable and capable of absorbing energy. The superelastic shape memory alloy wire damper may use a bundle of superelastic shape memory alloy wires connecting the first conical wall section 11 and the second conical wall section 12, wherein the distribution of the shape memory alloy wire bundle between the first conical wall section 11 and the second conical wall section 12 may be varied, for example, similar to the distribution of spokes on a bicycle wheel, or may take other forms.

Thus, when the engine normally works, the fusing part 14 can bear the load of the engine when the engine normally works, and at this time, the front section and the rear section of the bearing support conical wall 10, that is, the first conical wall section 11 and the second conical wall section 12 are tightly connected together, so that the support rigidity required by the normal work of the engine can be provided, that is, the bearing support conical wall 10 can completely restrain the front end bearing 5 in a normal state. When the actual load is higher than the predetermined load or the predetermined fusing threshold, the fusing part 14 will fuse and fail, for example, the fusing part 141 deforms and fails due to the action of the excessive load at the predetermined weak portion, and loses the limiting function. At this time, the front section and the rear section of the bearing support conical wall 10 are restrained by the elastic component 15, and relative displacement in the radial direction and the axial direction can be generated within the preset elastic range of the elastic component 15, so that the support rigidity provided for the fan shaft 2 by the front end bearing 5 is reduced, the critical rotating speed of the rotor is reduced, the transmission path is changed, and the FBO load transmitted to the stator component is reduced. When the relative displacement of the front and rear sections of the bearing support cone wall 10, i.e. the first cone wall section 11 and the second cone wall section 12, reaches the elastic limit of the elastic member 15, the further relative displacement of the two sections is limited, so as to provide constraint for the front and rear sections of the bearing support cone wall 10 and avoid the bearing support cone wall 10 from completely breaking after the FBO event occurs. The bearing supports the first half section of conical wall 10 like this and also first conical wall section 11 can not take place to bump with the fan axle 2 and rub and scratch because of losing the restraint totally and moving wantonly around fan axle 2, has avoided causing the damage of fan axle 2. Meanwhile, after the fusing part 14 is fused and fails, the elastic part 15 can absorb energy and reduce the load transmitted to the intermediate case 4 besides providing partial support.

In the illustrated embodiment, the fusing member 14 and the elastic member 15 may connect the first conical wall section 11 and the second conical wall section 12 in the radial direction, so that the front and rear sections of the bearing support conical wall 10, i.e. the first conical wall section 11 and the second conical wall section 12, have a certain overlap in the axial direction, and the overlap is separated in the radial direction to form a radial drop space.

In the illustrated embodiment, the fusing member 14 and the elastic member 15 are spaced apart by a predetermined distance in the axial direction. For example, the fusing member 14 and the elastic member 15 are annular thin plate members, and are arranged at intervals in the axial direction. In another embodiment, the fuse member 14 and the elastic member 15 may each be composed of a plurality of discrete ribs extending in the radial direction, the ribs being provided to connect the downstream end of the first conical wall section 11 and the upstream end of the second conical wall section 12, and the plurality of ribs constituting the fuse member 14 and the plurality of ribs constituting the elastic member 15 are provided at substantially the same positions in the axial direction and are spaced apart from each other in the circumferential direction.

In the illustrated embodiment, the fusing member 14 is located on the downstream side of the elastic member 15.

In the illustrated embodiment, the first tapered wall section 11 and the second tapered wall section 12 are also arranged in parallel in the axial direction, and the fuse member 14 and the elastic member 15 are arranged perpendicularly to the first tapered wall section 11 and the second tapered wall section 12. The downstream end of the first tapered wall section 11 and the upstream end of the second tapered wall section 12 and the fusing member 14 and the elastic member 15 constitute a rectangular region B therebetween.

furthermore, the axial length of the first conical wall section 11 in the axial direction is smaller than the axial length of the second conical wall section 12. That is, the load shedding mechanism 13 connecting the first conical wall section 11 and the second conical wall section 12 is closer to the connection of the bearing support conical wall 10 (the first conical wall section 11) and the front end bearing 5 than the connection of the bearing support conical wall 10 (or the second conical wall section 12) and the intermediate casing 4.

The fan rotor support system described above provides a load shedding mechanism 13 that can prevent bearing support cone wall 10 from breaking and rubbing against fan shaft 2 in an FBO event. During normal operation of the engine, the fusing part 14 and the elastic part 15 can act together to limit the relative freedom of the front section and the rear section of the bearing supporting conical wall in all directions. In the event of an FBO, the fuse member 14, which is capable of fully constraining the degree of freedom between the front and rear segments of the bearing support cone wall of the front end bearing, fails at a predetermined local weak point. At this time, only the elastic part 15 is connected between the front section and the rear section of the bearing support conical wall. Under the action of FBO load, the elastic part 15 can deform according to preset deformation, on one hand, the energy transmitted from the front section to the rear section of the bearing supporting conical wall is absorbed, and on the other hand, the front section and the rear section of the bearing supporting conical wall are allowed to relatively displace within the range allowed by the deformation of the elastic part 15, so that the connection between the front end bearing 5 and the intermediate casing 4 is partially decoupled, and the supporting rigidity of the fan rotor at the front end bearing is reduced. The reduction of the supporting rigidity at the front end bearing can reduce the critical rotating speed of the rotor, so that the critical rotating speed is lower than the working rotating speed and higher than the rotating speed of a windmill, the self-centering effect of the rotor is exerted, and the FBO load transmitted to a stator part is reduced.

The above description is only for the specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art can understand the changes or substitutions within the technical scope of the present invention, and the present invention should be covered within the protection scope of the present invention.

Claims (10)

1. A fan rotor support system comprising a bearing support cone wall for supporting a bearing coupled to a fan rotor to an intermediate case, the bearing support cone wall comprising:

A first conical wall section, an upstream end of which is connected to a bearing;

A second tapered wall section, the downstream end of which is connected to an intermediate casing;

A fusing member connecting a downstream end of the first tapered wall section and an upstream end of the second tapered wall section and configured to fuse at a predetermined load; and

A resilient member connecting a downstream end of the first conical wall section and an upstream end of the second conical wall section.

2. The fan rotor support system of claim 1, wherein the fusing member and the elastic member connect the first tapered wall section and the second tapered wall section in a radial direction of the fan rotor.

3. The fan rotor support system of claim 2, wherein the fusing member and the elastic member are spaced apart by a predetermined distance in an axial direction of the fan rotor.

4. The fan rotor support system of claim 3, wherein the fusing member is located at a downstream side of the elastic member.

5. The fan rotor support system of claim 1, wherein an upstream end of the second conical wall section is terminated around an outer circumferential side of a downstream end of the first conical wall section.

6. the fan rotor support system of claim 1, wherein an axial length of the first conical wall section in an axial direction of the fan rotor is smaller than an axial length of the second conical wall section.

7. the fan rotor support system of claim 1, wherein the fuse member is a rigid member provided with a weak point.

8. The fan rotor support system of claim 7, wherein the weakened portion of the rigid member is a reduced thickness portion of the rigid member.

9. The fan rotor support system of claim 1, wherein the resilient member is comprised of a superelastic shape memory alloy wire damper.

10. The fan rotor support system of claim 1,

The first conical wall section and the second conical wall section are disposed in parallel, and the fusing member and the elastic member are disposed perpendicular to the first conical wall section, in a cross section taken along a center axis of the fan rotor.