An aeroengine and its supporting structure with metal rubber

Abstract

The present invention belongs to the field of aero-engine safety design, and discloses an aero-engine and a supporting structure with metal rubber. In this supporting structure: on one side of the rigid bearing seat opposite to the axial baffle, a first force transmission boss and a second force transmission boss are respectively fixedly connected. Both the first and second force transmission bosses are located in an annular groove, and an elastic ring is also arranged in the annular groove. At both ends of the elastic ring, notch parts into which the first and second force transmission bosses are embedded are respectively arranged. When a blade of the aero-engine is lost, the first and second force transmission bosses break, and the fulcrum load is sequentially transmitted outward through the fulcrum bearing, the elastic ring and the rigid bearing seat. The safety design of the supporting structure of the present invention can achieve a stiffness mutation under the action of a large fulcrum dynamic load after the blade is lost, and does not release the fulcrum constraint, avoiding large-amplitude vibration of the fan, preventing bearing seizure failure, ensuring that the rotor can rotate stably, and having high safety.

Description

Technical Field

[0001] The present invention belongs to the field of aero-engine safety design, and particularly relates to an aero-engine and a supporting structure thereof with metal rubber. Background Art

[0002] The loss of a blade is an extreme and complex load state for an aero-engine. With the development of industrial technology, the diameter of the fan blades of aero-engines is getting larger and larger, the unbalanced load generated by blade loss accidents is also getting larger, and the harmfulness of the accidents is becoming more and more serious. Europe's CS-E and China's CCAR have put forward safety requirements for blade loss faults: the aero-engine design department needs to ensure that after a blade is lost, the broken parts are contained and do not cause secondary damage to the engine; the engine remains suspended on the wing without falling off; there is no fire, and it can maintain operation.

[0003] In order to reduce the harm caused by blade loss, the traditional method is to increase the structural strength of key parts. Such a practice will lead to an increase in the mass of the engine, which is not conducive to the weight reduction design of aero-engines. In recent years, in order to reduce the harm brought by blade loss to aero-engines, safety design is generally carried out structurally through a reasonable layout of the structure of aero-engines.

[0004] The biggest dangerous point of the unbalanced rotor system after blade loss lies in the sudden increase in the vibration response when the rotor system passes through the critical speed. Seriously, the excessive dynamic load at the support point will directly cause secondary accidents such as bearing jamming and shaft breakage. In order to avoid secondary accidents brought to the aero-engine rotor system by the unbalanced load after blade loss, a common design scheme is to design an instantaneous break structure at the No. 1 support point closest to the fan blade, so that the rotor system loses a bearing support point, changes the dynamic characteristics of the rotor, reduces the peak value of the dynamic load at the support point of the rotor, and avoids the destruction of other key components.

[0005] However, when the fan shaft loses the support bearing, the constraint of the rotor will be released, and only the second bearing can be relied on to constrain the large-diameter fan. Under the action of a large unbalanced load, the displacement amplitude of the fan component is larger than before. This will cause large-amplitude vibration of the fan blades, which will cause local bending deformation and stress concentration of the fan shaft at the second bearing due to being constrained. The large-radius vibration will cause serious rubbing between the blades and the fan casing, cause non-coordinated whirling of the rotor, generate anti-precession or bending-torsion coupling vibration, and cause the fan shaft to become unstable, endangering the safety of the aircraft. Therefore, through reasonable design of the structure, it is necessary to not only reduce the peak value of the dynamic load at the support point of the rotor, but also constrain the large-diameter vibration of the fan disk to ensure the safety of the aero-engine. Summary of the Invention

[0006] To solve the above technical problems, the present invention provides an aeroengine and its supporting structure with metal rubber to solve the problems in the prior art. To achieve the above invention purpose, the technical solution adopted by the present invention is as follows:

[0007] A supporting structure with metal rubber, applied to an aeroengine, includes a rigid bearing seat and an axial baffle arranged on a pivot bearing. The rigid bearing seat is connected to the axial baffle and is connected to the intermediate load-bearing frame of the aeroengine. An annular groove is formed between the rigid bearing seat and the axial baffle, and the outer side of the pivot bearing is arranged in the annular groove.

[0008] On the opposite sides of the rigid bearing seat and the axial baffle, a first force-transferring boss and a second force-transferring boss are respectively fixedly connected. The first and second force-transferring bosses are both located in the annular groove. An elastic ring is also arranged in the annular groove. Notches into which the first and second force-transferring bosses are inserted are respectively arranged at both ends of the elastic ring. The inner and outer sides of the elastic ring are respectively abutted against the outer side of the pivot bearing and the inner side of the rigid bearing seat.

[0009] When a blade of the aeroengine is lost, the first and second force-transferring bosses break, and the pivot load is sequentially transmitted outward through the pivot bearing, the elastic ring, and the rigid bearing seat.

[0010] Further, the elastic ring includes an outer-layer metal rubber elastic ring, a middle-layer metal rubber elastic ring, and an inner-layer metal rubber elastic ring arranged in sequence from outside to inside. The outer-layer metal rubber elastic ring and the inner-layer metal rubber elastic ring have the same width and are greater than the width of the middle-layer metal rubber elastic ring, so as to form the notches at both ends of the middle-layer metal rubber elastic ring.

[0011] Further, the rigid bearing seat includes a fixed mounting edge, a horizontal edge, and a vertical edge. The lower side of one end of the horizontal edge is fixedly connected to the vertical edge, and the upper side of the other end is fixedly connected to the fixed mounting edge. The fixed mounting edge is detachably connected to the axial baffle, and a gap is provided between the vertical edge and the axial baffle to form the annular groove.

[0012] Further, the first force-transferring boss is fixedly connected to the vertical edge, the second force-transferring boss is fixedly connected to the axial baffle, the outer side of the elastic ring is abutted against the inner side of the horizontal edge, and the axial baffle is attached to the fixed mounting edge.

[0013] Further, first grooves and second grooves are respectively arranged on the upper and lower sides of the end of the first force-transferring boss connected to the vertical edge and on the upper and lower sides of the end of the second force-transferring boss connected to the axial baffle to reduce the strength of the first and second force-transferring bosses at this part.

[0014] Further, the thicknesses of the first force - transmitting boss and the second force - transmitting boss are equal, and the thickness values are obtained through strength calculation.

[0015] Further, the fixed mounting edge and the axial baffle are connected to the bearing cone shell mounting edge on the intermediate bearing frame through bolts.

[0016] An aero - engine, wherein the intermediate bearing frame and the pivot bearing adopt the supporting structure described in any one of the claims to support.

[0017] Further, the pivot bearing is installed on the fan shaft, a fan blade disk is installed on the fan shaft, and the intermediate bearing frame is connected to the fan shaft through a second bearing.

[0018] The present invention has the following beneficial effects:

[0019] The safety design of the supporting structure of the present invention can achieve a stiffness mutation under the action of a large pivot dynamic load after a blade is lost, and does not release the pivot constraint, avoiding large - amplitude vibration of the fan, preventing bearing seizure failure, ensuring that the rotor can rotate stably, having high safety, and can also achieve a variable - stiffness design of the rotor support, changing the dynamic characteristics of the rotor system, absorbing vibration energy by the elastic ring 2, and reducing the transmission of the pivot dynamic load. Description of the Drawings

[0020] Figure 1 It is a cross - sectional view of a typical high - bypass - ratio turbofan aero - engine in the present invention.

[0021] Figure 2 is Figure 1 an enlarged view of part A in

[0022] Figure 3 is Figure 2 an enlarged view of, in which the left side is an enlarged view of part B1 and the right side is an enlarged view of part B2;

[0023] Figure 4 It is the force - transmitting route of the pivot dynamic load of the supporting structure when the aero - engine in the present invention is operating normally.

[0024] Figure 5 It is the force - transmitting route of the pivot dynamic load of the supporting structure after a blade is lost in the present invention. Detailed Embodiments

[0025] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the Figures 1-5 in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. If not specifically specified, the technical means used in the embodiments are conventional means well - known to those skilled in the art.

[0026] Reference Figure 1 , which is the specific structure of the aero-engine 9 of the present invention. It includes a fan blade disk 91, a fan shaft 92, a fulcrum bearing 4, an intermediate load-bearing frame 93, and a second bearing 94. The intermediate load-bearing frame 93 and the fulcrum bearing 4 are supported by the supporting structure of the present invention. The fulcrum bearing 4 is installed on the fan shaft 92, the fan blade disk 91 is installed on the fan shaft 92, and the intermediate load-bearing frame 93 is connected to the fan shaft 92 through the second bearing 94.

[0027] The aero-engine 9 of the present invention is a high bypass ratio turbofan engine. The present invention is mainly used for the safety design of a supporting structure of the fulcrum bearing 4 of a high bypass ratio turbofan engine. The fulcrum bearing 4 is a prior art, and specifically includes a bearing outer ring 41, rollers 42, a cage 43, and a bearing inner ring 44.

[0028] It should be noted that Figures 2-5 is a cross-sectional schematic diagram. The fulcrum bearing 4, the rigid bearing seat 1, the axial baffle 3, and the elastic ring 2 of the present invention are coaxial annular rotating body structures. Figure 4 , Figure 5 The arrows in are the force transmission routes of the fulcrum dynamic load.

[0029] Reference Figure 2 , which is a supporting structure with metal rubber of the present invention, applied to the aero-engine 9. It includes a rigid bearing seat 1 and an axial baffle 3 arranged on the fulcrum bearing 4. The rigid bearing seat 1 is connected to the axial baffle 3 and is connected to the intermediate load-bearing frame 93 of the aero-engine 9. A circular groove is formed between the rigid bearing seat 1 and the axial baffle 3. The radial outer side of the fulcrum bearing 4 is arranged in the circular groove, that is, the bearing outer ring 41 is located in the circular groove;

[0030] On the opposite sides of the rigid bearing seat 1 and the axial baffle 3, a first force transmission boss 14 and a second force transmission boss 31 are respectively fixedly connected. The first and second force transmission bosses are both located in the circular groove. An elastic ring 2 is also arranged in the circular groove. Notches into which the first and second force transmission bosses are embedded are respectively arranged at both ends of the elastic ring 2. The radial inner and outer sides of the elastic ring 2 are respectively abutted against the radial outer side of the fulcrum bearing 4 and the radial inner side of the rigid bearing seat 1, that is, in Figure 2 , the upper and lower sides of the elastic ring 2 respectively abut against the radial inner side of the rigid bearing seat 1 and the radial outer side of the bearing outer ring 41.

[0031] When a blade 91 of the aero-engine 9 flies off, the first and second force transmission bosses break, and the fulcrum load is sequentially transmitted outward through the fulcrum bearing 4, the elastic ring 2, and the rigid bearing seat 1.

[0032] As Figure 4, during the normal operation of the aero-engine 9, the vibration response of the engine 9 is at a relatively low level. The pivot dynamic load is transmitted through the pivot bearing 4, and through the pivot bearing 4 (specifically the bearing outer ring 41), it is introduced into the first force transmission boss 14 and the second force transmission boss 31 and transmitted outward.

[0033] Such as Figure 5 , the blade loss is a typical severe accident of modern aero-engines. When a blade 91 of the aero-engine 9 is lost, the pivot dynamic load at the engine bearing 4 is too large, and the first force transmission boss 14 and the second force transmission boss 31 are fractured and no longer participate in the load transmission. The pivot dynamic load of the engine is directly introduced into the elastic ring 2 through the pivot bearing 4, and then transmitted outward to the intermediate bearing frame 93 through the rigid bearing seat 1.

[0034] After the blade loss fault occurs, the annular groove between the rigid bearing seat 1 and the axial baffle 3 still forms a limit constraint on the pivot bearing 4. Therefore, the pivot bearing 4 can still achieve the rotation function.

[0035] The support structure designed by the present invention can achieve a stiffness mutation under the action of a large pivot dynamic load after the blade loss, and does not release the pivot constraint, avoiding large-amplitude vibration of the fan, preventing bearing seizure and damage, ensuring that the rotor can rotate stably, having high safety, and can also achieve variable stiffness design of the rotor support, changing the dynamic characteristics of the rotor system, using the elastic ring 2 to absorb vibration energy and reducing the outward transmission of the pivot dynamic load.

[0036] And the designed instantaneous break vibration damping structure (the first and second force transmission bosses) of the support structure is placed outside the pivot bearing 4, which does not affect the lubricating oil supply of the bearing pivot system, has no influence on the under-ring oil supply or side-position oil supply, and has a simple structure and is convenient to install, reducing the design, processing and assembly costs.

[0037] Reference Figure 2 、 Figure 3 , the following describes the specific structure of the elastic ring 2:

[0038] The elastic ring 2 includes an outer metal rubber elastic ring 21, a middle metal rubber elastic ring 22 and an inner metal rubber elastic ring 23 arranged in sequence from outside to inside, that is, the outer metal rubber elastic ring 21 is located at the outermost radial position, and the inner metal rubber elastic ring 23 is located at the innermost radial position.

[0039] The outer metal rubber elastic ring 21 and the inner metal rubber elastic ring 23 have the same width and are greater than the width of the middle metal rubber elastic ring 22, so as to form the notch part at both ends of the middle metal rubber elastic ring 22. Specifically, the outer metal rubber elastic ring 21, the middle metal rubber elastic ring 22 and the inner metal rubber elastic ring 23 together form an "I"-shaped cross-section structure.

[0040] Preferably, the thickness of the inner metal rubber elastic ring 23 is less than that of the outer and middle metal rubber elastic rings. During the normal operation of the aero-engine 9, in order to control the vibration response of the engine and ensure the stable output of the engine thrust, a thin metal rubber elastic ring 23 is added outside the pivot bearing 4 (specifically, the bearing outer ring 41) for damping and energy absorption when the rotor system of the aero-engine 9 passes through the critical speed, and to adjust the dynamic characteristics of the rotor system during normal operation.

[0041] Reference Figure 2 、 Figure 3 , the specific structure of the rigid bearing seat 1 will be described below:

[0042] The rigid bearing seat 1 includes a fixed mounting edge 11, a horizontal edge 12 and a vertical edge 13. The lower side of one end of the horizontal edge 12 is fixedly connected to the vertical edge 13, and the upper side of the other end is fixedly connected to the fixed mounting edge 11. The fixed mounting edge 11 is detachably connected to the axial baffle 3, and a gap is provided between the vertical edge 13 and the axial baffle 3 to form the annular groove.

[0043] Specifically, the mounting edge 11, the horizontal edge 12 and the vertical edge 13 can be fixedly connected or integrally formed. The horizontal edge 12 is horizontally arranged, the mounting edge 11 is vertically arranged below one end of the horizontal edge 12, and the vertical edge 13 is vertically arranged above the other end of the horizontal edge 12. The inner ring surface 121 on the radial inner side of the mounting edge 11 radially positions the elastic ring 2.

[0044] Furthermore, the first force transmission boss 14 is fixedly connected to the vertical edge 13, the second force transmission boss 31 is fixedly connected to the axial baffle 3. The outer side of the elastic ring 2, that is, the outer metal rubber elastic ring 21 abuts against the inner side of the horizontal edge 12, and the axial baffle 3 abuts against the fixed mounting edge 11.

[0045] Furthermore, first grooves 141 and second grooves 311 are respectively provided on the upper and lower sides of the end of the first force transmission boss 14 connecting the vertical edge 13 and on the upper and lower sides of the end of the second force transmission boss 31 connecting the axial baffle 3 to reduce the strength of the first and second force transmission bosses at this part.

[0046] Specifically, this part refers to the roots of the first and second force transmission bosses, that is, the ends where they are respectively connected to the vertical edge 13 and the axial baffle 3. The first grooves 141 and the second grooves 311 are respectively located on the upper and lower sides of the root of the first force transmission boss 14.

[0047] Furthermore, the thicknesses of the first force transmission boss 14 and the second force transmission boss 31 are equal, and their thickness values are obtained through strength calculation.

[0048] Specifically, the fulcrum dynamic load after the fan blade flies off is dozens or even hundreds of times that of the fulcrum dynamic load in the normal working state of the engine. The thicknesses of the first force transmission boss 14 and the second force transmission boss 31 need to ensure stable force transmission without fracture under the normal working state of the engine, and fracture occurs when the fulcrum dynamic load is too large.

[0049] In addition, when the thickness values of the first force transmission boss 14 and the second force transmission boss 31 are obtained through strength calculation, the method includes:

[0050] First, calculate the fulcrum dynamic load in the maximum working state of the engine and the fulcrum dynamic load after the blade flies off; according to the first strength theory: σ1 ≤ [σ], the thickness of the force transmission boss can ensure that the force transmission boss does not fracture under the fulcrum dynamic load of 5 - 10 times the maximum working condition of the engine, that is, σ1 calculated from 10 times the maximum working condition load is [σ], where σ1 is the maximum tensile stress at the dangerous point (the first groove 141 and the second groove 311) of the force transmission boss, and [σ] is the allowable stress for unidirectional tension, and [σ] is determined according to the material of the force transmission boss.

[0051] Furthermore, the fixed mounting edge 11 and the axial baffle 3 are connected to the bearing cone housing mounting edge 6 on the intermediate load-bearing frame 93 through bolts 5.

[0052] Specifically, the bearing cone housing mounting edge 6 is a component on the intermediate load-bearing frame 93. The bolt 5 passes through the bearing cone housing mounting edge 6, the fixed mounting edge 11, and the axial baffle 3, and is locked by a nut.

[0053] The above-described embodiments are only descriptions of the preferred modes of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations, variations, modifications, and substitutions made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A support structure with metal rubber, applied to an aero-engine (9), characterized in that: It includes a rigid bearing seat (1) and an axial baffle (3) arranged on a pivot bearing (4). The rigid bearing seat (1) is connected to the axial baffle (3) and is connected to an intermediate load-bearing frame (93) of an aero-engine (9). An annular groove is formed between the rigid bearing seat (1) and the axial baffle (3), and the outer side of the pivot bearing (4) is arranged in the annular groove. On the opposite sides of the rigid bearing seat (1) and the axial baffle (3), a first force-transmitting boss (14) and a second force-transmitting boss (31) are respectively fixedly connected. Both the first and second force-transmitting bosses are located in the annular groove. An elastic ring (2) is also arranged in the annular groove. At both ends of the elastic ring (2), there are notch parts into which the first and second force-transmitting bosses are inserted. The inner and outer sides of the elastic ring (2) are respectively abutted against the outer side of the pivot bearing (4) and the inner side of the rigid bearing seat (1). When a blade (91) of the aero-engine (9) is lost, the first and second force-transmitting bosses break, and the pivot load is sequentially transmitted outward through the pivot bearing (4), the elastic ring (2), and the rigid bearing seat (1).

2. The support structure with metal rubber according to claim 1, characterized in that: The elastic ring (2) includes an outer-layer metal rubber elastic ring (21), a middle-layer metal rubber elastic ring (22), and an inner-layer metal rubber elastic ring (23) arranged in sequence from outside to inside. The outer-layer metal rubber elastic ring (21) and the inner-layer metal rubber elastic ring (23) have the same width and are wider than the width of the middle-layer metal rubber elastic ring (22), so as to form the notch parts at both ends of the middle-layer metal rubber elastic ring (22).

3. A support structure with metal rubber according to claim 1, characterized in that: The rigid bearing seat (1) includes a fixed mounting edge (11), a horizontal edge (12), and a vertical edge (13). The lower side of one end of the horizontal edge (12) is fixedly connected to the vertical edge (13), and the upper side of the other end is fixedly connected to the fixed mounting edge (11). The fixed mounting edge (11) is detachably connected to the axial baffle (3), and a gap is provided between the vertical edge (13) and the axial baffle (3) to form the annular groove.

4. A support structure with metal rubber according to claim 3, characterized in that: The first force-transmitting boss (14) is fixedly connected to the vertical edge (13), the second force-transmitting boss (31) is fixedly connected to the axial baffle (3), the outer side of the elastic ring (2) is abutted against the inner side of the horizontal edge (12), and the axial baffle (3) is attached to the fixed mounting edge (11).

5. A support structure with metal rubber according to claim 4, characterized in that: On the upper and lower sides of one end of the first force-transmitting boss (14) connecting the vertical edge (13) and on the upper and lower sides of one end of the second force-transmitting boss (31) connecting the axial baffle (3), a first groove (141) and a second groove (311) are respectively provided to reduce the strength of the roots of the first and second force-transmitting bosses.

6. A support structure with metal rubber according to any one of claims 1-5, characterized in that: The first force-transmitting boss (14) and the second force-transmitting boss (31) have the same thickness, and the thickness value is obtained through strength calculation.

7. A support structure with metal rubber according to claim 3, characterized in that: The fixed mounting edge (11) and the axial baffle (3) are connected to a bearing cone shell mounting edge (6) on the intermediate load-bearing frame (93) through bolts (5).

8. An aeroengine, wherein a supporting structure as described in any one of claims 1-7 is adopted to support between an intermediate bearing frame (93) and a pivot bearing (4).

9. An aeroengine according to claim 8, characterized in that: The pivot bearing (4) is installed on a fan shaft (92), a fan blade disk (91) is installed on the fan shaft (92), and the intermediate bearing frame (93) is connected to the fan shaft (92) through a second bearing (94).

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