Multi-point common load-bearing structure between turbine stages with high vibration isolation

Abstract

The present invention belongs to the technical field of aircraft engine structural layout design, and specifically relates to a multi-support shared load-bearing structure between turbine stages with high vibration isolation, including a shared bearing seat and a broadband vibration reduction structure. The shared bearing seat is in the shape of a "human", including a bearing seat body, a front support arm and a rear support arm. The end of the front support arm away from the bearing seat body is connected to the front support rotation structure, and the end of the rear support arm away from the bearing seat body is connected to the rear support rotation structure; the broadband vibration reduction structure is combined and connected between the shared bearing seat and the turbine interstage casing. In the case where the excitation energy input cannot be reduced, the present invention improves the overall vibration isolation of the load-bearing structure by optimizing the configuration, setting elastic supports and dry friction energy dissipation structures, and reduces the vibration response level of the shared load-bearing structure between the stages during transmission to the outer casing of the aircraft engine, so as to prevent structural damage.

Description

Technical Field

[0001] The present invention belongs to the technical field of aircraft engine structure layout design, and in particular relates to a turbine inter-stage multi-support point shared load-bearing structure with high vibration isolation. Background Art

[0002] In the design of modern advanced high-power-to-weight turboshaft / turboprop engines, a shared load-bearing structure between turbine stages is often used to support multiple rotors. This reduces the number of load-bearing structures, reduces engine weight, and meets dimensional constraints and lightweight requirements. For example, the patent "Three-Spindle Turbofan Engine" with publication number CN115492681A uses an interstage load-bearing frame, which reduces the engine's structural complexity and improves its reliability and safety. However, the shared load-bearing frame simultaneously supports multiple rotors with different rotational speeds, subjecting them to more complex vibration excitation loads. In particular, the shared load-bearing structure between high- and low-pressure turbine stages faces even more severe challenges in terms of load-bearing capacity, deformation control, and dynamic design due to the harsh temperature environment.

[0003] In the design of turbine interstage load-bearing structures, multiple layers of cooling air are often introduced to protect bearings, supports, and other load-bearing structures in harsh, high-temperature environments, preventing overall deformation and thermal stress damage. However, these structures also incorporate sealing structures such as multi-layered plate-shell grates. Airflow excitation and friction at the grates generate complex, broadband excitation loads, which can not only cause localized vibration damage to the sealing structure but can also induce complex vibration responses in the load-bearing frame upon transmission.

[0004] At present, the design of load-bearing structures is mostly focused on their load-bearing capacity. For example, the patent "A bird skeleton bionic load-bearing structure and its design method" with publication number CN115288804A proposes to use bird bionic fitting to form a load-bearing skeleton curve, and design a variable thickness load-bearing skeleton according to the load distribution. Another example is the patent "A gas turbine intermediate casing and its reinforcement structure" with publication number CN114526161A. By connecting reinforcement wall panels to the supporting inner wall of the intermediate casing, the structure of the supporting inner wall is strengthened, so that when the air flow instability occurs in the bearing sealing cavity, it has stronger structural stability. Existing research directions are mainly focused on the high load-bearing capacity design of load-bearing structures. However, with the expansion of the speed range, for multi-point shared load-bearing structures, there are multiple excitation effects of the rotor on the load-bearing structure. At present, there are few studies on how to improve its vibration isolation and other related aspects.

[0005] Turbine interstage bearing structures, operating in harsh environments, are subject to complex excitation loads such as multiple rotors, sealed airflow, and localized friction. Their diverse plate and shell configurations create complex vibration modes and are susceptible to excitation loads. Therefore, their dynamic design is a key challenge that currently needs to be addressed. There is an urgent need to design high-vibration-isolation turbine interstage bearing structures to minimize vibration transmission, avoid vibration coupling between pivot points and the structure, and reduce sensitivity to load variations. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention provides a turbine inter-stage multi-support shared load-bearing structure with high vibration isolation. When the excitation energy input cannot be reduced, the overall vibration isolation of the load-bearing structure is improved by optimizing the configuration, setting elastic supports and dry friction energy dissipation structures, and reducing the vibration response level of the inter-stage shared load-bearing structure in the process of being transmitted to the outer casing of the aircraft engine, so as to prevent structural damage.

[0007] The present invention is achieved in this way: a multi-support shared load-bearing structure between turbine stages with high vibration isolation is provided, including a common bearing seat and a broadband vibration reduction structure. The common bearing seat is in the shape of a "human", including a bearing seat body, a front support arm and a rear support arm. The end of the front support arm away from the bearing seat body is connected to the front support rotation structure, and the front support rotation structure is connected to the rear support of the high-pressure turbine through high and low pressure rotating shafts. The end of the rear support arm away from the bearing seat body is connected to the rear support rotation structure, and the rear support rotation structure is connected to the rear support of the low-pressure turbine through high and low pressure rotating shafts; the broadband vibration reduction structure is combined and connected between the common bearing seat and the turbine interstage casing.

[0008] Preferably, the front fulcrum rotation structure and the rear fulcrum rotation structure both include a rotation structure shell, an elastic ring damping structure and bearings, the high and low pressure shafts pass through the bearings, the bearings are arranged on the inner side of the elastic ring damping structure, and the elastic ring damping structure is arranged in the rotation structure shell.

[0009] It is further preferred that a second welding point is provided on the high-pressure turbine side of the rotating structure housing of the front support rotating structure, and the second welding point is connected to the rear support of the high-pressure turbine through a first brush sealing structure; and a third welding point is provided on the low-pressure turbine side of the bearing seat body, and the third welding point is connected to the rear support of the low-pressure turbine through a second brush sealing structure.

[0010] Further preferably, the broadband vibration damping structure includes a discontinuous load-bearing structure and a grate sealing structure, the discontinuous load-bearing structure includes a load-bearing drum and a deflector, the two sides of the deflector are the deflector inner casing and the deflector outer casing respectively, the bearing seat body is connected to the load-bearing drum, the other side of the load-bearing drum is connected to the deflector inner casing, and the side of the deflector outer casing away from the deflector is connected to the turbine interstage casing through the return deflector mounting edge; the high-pressure turbine side of the bearing seat body is connected to the grate sealing structure.

[0011] Further preferably, the comb teeth sealing structure includes a first folding load-bearing cone shell, a second folding load-bearing cone shell and a third folding load-bearing cone shell, one end of the first folding load-bearing cone shell and the second folding load-bearing cone shell is connected to the bearing seat body, the other end of the first folding load-bearing cone shell is provided with a first sealing bushing, the end of the third folding load-bearing cone shell in contact with the first sealing bushing is provided with a first comb teeth structure, the other end of the second folding load-bearing cone shell is provided with a second sealing bushing, the end of the third folding load-bearing cone shell in contact with the second sealing bushing is provided with a second comb teeth structure, and the lower end of the third folding load-bearing cone shell is connected to the high-pressure turbine.

[0012] It is further preferred that reinforcing ribs are provided in the reversible load-bearing cone shell; a dry friction damping shock-absorbing structure is provided in the second reversible load-bearing cone shell, and the dry friction damping shock-absorbing structure includes a vibration-absorbing and energy-absorbing spring piece, one end of the vibration-absorbing and energy-absorbing spring piece is connected to the second reversible load-bearing cone shell, and the other end is a free end, and the vibration-absorbing and energy-absorbing spring piece contacts the surface of the second reversible load-bearing cone shell to form a dry friction contact surface; a groove structure is provided on the side of the first comb tooth structure away from the first reversible load-bearing cone shell, and one end of the dry friction spring piece is installed in the groove structure, and the other end contacts the outer wall of the first comb tooth structure outside the groove structure.

[0013] Further preferably, a step structure is provided on the side of the second sealing bushing that contacts the second comb tooth structure.

[0014] Further preferably, the bearing seat body is provided with a first flange mounting edge and a second flange mounting edge, the first flange mounting edge is connected to the load-bearing drum through a first flange bolt connection structure, and the second flange mounting edge is connected to the first fold-back load-bearing cone shell through a second flange bolt connection structure, and a first welding point is provided on the bearing seat body, which is connected to the second fold-back load-bearing cone shell through the first welding point; the fold-back deflector mounting edge is connected to the turbine interstage casing through a third flange bolt connection structure.

[0015] Compared with the prior art, the advantages of the present invention are:

[0016] 1. The present invention adopts a staggered layout scheme of weak-rigidity rotating structures and return structures with high-rigidity bearing seats and load-bearing frames on the main load-bearing route of the fulcrum, and applies an extrusion oil film damping structure to improve the overall vibration isolation of the load-bearing structure and reduce the external vibration response;

[0017] 2. The present invention adopts a "human" shaped tapered shell bearing seat structure to achieve two-point support, ensuring the overall load-bearing capacity and anti-deformation ability. At the same time, the "human" bearing seat geometric cross-section change and the elastic ring squeeze oil film damping structure at the support point improve the inter-support vibration resistance and effectively avoid vibration coupling between the support points.

[0018] 3. The present invention is aimed at multi-pass sealing structures such as grate teeth used in the cooling flow path of the turbine inter-stage load-bearing structure. It adopts structural bending, dry friction energy dissipation, etc. to achieve broadband vibration energy isolation and dissipation, and realize high vibration isolation between the sealing structure and the main load-bearing structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A partial cross-sectional view of the multi-support point common load-bearing structure between turbine stages provided by the present invention;

[0020] Figure 2 An axonometric diagram of the multi-point shared load-bearing structure between turbine stages provided by the present invention (the shared bearing seat is omitted);

[0021] Figure 3 This is an enlarged cross-sectional view of the common bearing seat;

[0022] Figure 4 It is a three-dimensional diagram of the elastic ring damping structure;

[0023] Figure 5 This is a three-dimensional diagram of the grate tooth sealing structure;

[0024] Figure 6 Schematic diagram of the dry friction damping and shock absorption structure in the grate tooth sealing structure. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0026] refer to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 and Figure 6 This embodiment provides a multi-support shared load-bearing structure between turbine stages with high vibration isolation. The purpose is to improve its key design parameters such as stiffness characteristics and vibration isolation capability on the basis of optimizing the structural design of the load-bearing structure, so that it has stable stiffness characteristics within a wide frequency range under the action of complex support dynamic loads. At the same time, the stiffness of the load-bearing structure has low sensitivity to changes in load frequency and size, thereby reducing vibration and improving stability.

[0027] See also Figure 1The multi-point shared load-bearing structure between turbine stages includes a turbine interstage casing 6, an outer deflector casing 5, an inner deflector casing 3, a folding deflector mounting edge 11, a deflector (load-bearing auxiliary plate) 4, a folding load-bearing drum 2, and a "human" shaped shared bearing seat 1; the folding deflector mounting edge 11 is connected to the turbine interstage casing 6 and the outer deflector casing 5 respectively through a third bolt connection structure 30. This structural form is conducive to shortening the force transmission path and releasing the thermal stress generated by the radial temperature gradient. In addition, the folding cone shell can also provide appropriate bending stiffness, improve the overall stiffness and deformation resistance of the load-bearing frame, and effectively attenuate and isolate vibration energy.

[0028] The first flange mounting edge of the common bearing seat forms a folded ring shell structure with the folded load-bearing drum 2 through the first bolt connection structure 27. At the same time, in the common bearing seat 1, the front support arm extends forward and the rear support arm extends backward to form a "human" shaped cone shell structure, which improves the overall stiffness and deformation resistance of the load-bearing frame; and the support arms of the front and rear supports form a folded structure with the main body of the bearing seat. The support arms have certain bending and cross-sectional changes, forming a discontinuous structure, which enhances the vibration isolation between multiple supports.

[0029] See also Figure 3 and Figure 4 The elastic ring damping structure includes a limit ring 36, an elastic ring 37, and a squeeze film damper 38. The elastic ring 37 is installed between the bearing outer ring and the squeeze film damper 38 through the limit ring 36. The squeeze film damper 38 is located between the limit ring 36 and the rotating structure housing 12. The elastic ring 37 forms a lubricating oil cavity with the inner and outer bosses through the elastic ring 37. The elastic ring 37 is perforated with oil holes. When the rotor shaft journal drives the elastic ring 37 to undergo lateral displacement, the lubricating oil flows rapidly between the inner and outer cavities through the oil seepage holes in the elastic ring 37, forming an oil film pressure field to achieve a damping and vibration reduction effect. At the same time, the support stiffness can be adjusted without increasing the axial dimension.

[0030] See also Figure 5 and Figure 6 The grate sealing structure includes a first folding load-bearing cone shell 14, a second folding load-bearing cone shell 15 and a third folding load-bearing cone shell 16, a reinforcing rib 25, a first sealing bushing 19, a second sealing bushing 20, a first grate structure 17 and a second grate structure 18 distributed on the high-pressure turbine and matched with the sealing bushing, as well as vibration-absorbing and energy-absorbing spring fragments 22 and dry friction spring fragments 24 distributed on the first sealing bushing 19, the second sealing bushing 20 and the first grate structure 17 and the second grate structure 18. The mating surface between the second sealing bushing 20 and the second grate structure 18 is provided with a step.

[0031] In order to improve the vibration isolation of the grate sealing structure, a folded-back configuration mutation structure is adopted. The first folded-back load-bearing cone shell 14 and the first sealing bushing 19 constitute a folded-back load-bearing cone shell structure, and reinforcing ribs 25 are designed to form an annular cavity structure; a third folded-back load-bearing cone shell 16 is adopted on the high-pressure turbine shaft neck corresponding to the grate sealing structure; when local resonance occurs in the grate sealing structure, the multiple folded-back discontinuous structures designed can effectively attenuate and isolate the vibration energy during vibration propagation, avoiding the rotor vibration excitation load causing a large dynamic response of the load-bearing spokes, casing and other stators, and preventing vibration damage to the load-bearing structure. At the same time, the multi-stage grate sealing structure is suitable for the high cooling and high sealing requirements of modern engine turbine components.

[0032] The vibration-absorbing and energy-dissipating springs 22 in the dry friction damping and shock-absorbing structure 21 are installed on the stator grate sealing assembly by tightening bolts to form a dry friction contact surface 23. The dry friction contact surface 23 is used to introduce nonlinear stiffness and damping characteristics. When the multi-stage grate sealing structure vibrates in the radial direction (vertical direction), the vibration-absorbing and energy-dissipating springs 13d resonate. At the local overlap, there are complex contact behaviors such as separation-contact-slapping, which produce local constraint stiffness with significant nonlinear characteristics, bringing rich nonlinear vibration characteristics to the grate sealing structure, which can effectively expand its resonance bandwidth and realize efficient transfer of broadband vibration energy; at the same time, the viscous-slip friction behavior at the interface of the vibration-absorbing and energy-dissipating springs 22 and the dry friction springs 24 when they vibrate can produce nonlinear dry friction damping, thereby realizing the hysteresis damping dissipation effect.

[0033] When designing the resonance frequency of the vibration-absorbing and energy-dissipating spring piece 22 and the dry friction spring piece 24, it is determined by the stiffness and mass of the dry friction spring piece. The mass / stiffness distribution design can be performed based on the excitation load characteristics, so as to utilize the spring piece's own resonance to achieve dynamic vibration absorption within the sensitive excitation frequency band.

[0034] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various deformations, modifications, and substitutions made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A multi-support common load-bearing structure between turbine stages with high vibration isolation, characterized by: The invention comprises a common bearing seat (1) and a broadband vibration reduction structure. The common bearing seat (1) is in the shape of a "human" and comprises a bearing seat body (101), a front support arm (102) and a rear support arm (103). The end of the front support arm (102) away from the bearing seat body (101) is connected to the front support rotation structure (7). The front support rotation structure (7) is connected to the high-pressure turbine rear support (8) through the high-pressure and low-pressure rotating shafts. The end of the rear support arm (103) away from the bearing seat body (101) is connected to the rear support rotation structure (9). The rear support rotation structure (9) is connected to the low-pressure turbine rear support (10) through the high-pressure and low-pressure rotating shafts. The broadband vibration reduction structure is assembled and connected between the common bearing seat (1) and the turbine interstage casing (6). The broadband vibration reduction structure includes a discontinuous load-bearing structure and a grate sealing structure. The discontinuous load-bearing structure includes a load-bearing drum (2) and a deflector (4). The two sides of the deflector (4) are respectively the deflector inner casing (3) and the deflector outer casing (5). The bearing seat body (101) is connected to the load-bearing drum (2). The other side of the load-bearing drum (2) is connected to the deflector inner casing (3). The side of the deflector outer casing (5) away from the deflector (4) is connected to the turbine interstage casing (6) through a fold-back deflector mounting edge (11); the high-pressure turbine side of the bearing seat body (101) is connected to the grate sealing structure. The grate sealing structure includes a first folding bearing cone shell (14), a second folding bearing cone shell (15) and a third folding bearing cone shell (16), one end of the first folding bearing cone shell (14) and the second folding bearing cone shell (15) are connected to the bearing seat body (101), the other end of the first folding bearing cone shell (14) is provided with a first sealing bushing (19), the end of the third folding bearing cone shell (16) in contact with the first sealing bushing (19) is provided with a first grate structure (17), the other end of the second folding bearing cone shell (15) is provided with a second sealing bushing (20), the end of the third folding bearing cone shell (16) in contact with the second sealing bushing (20) is provided with a second grate structure (18), and the lower end of the third folding bearing cone shell (16) is connected to the high-pressure turbine.

2. The turbine inter-stage multi-support common load-bearing structure with high vibration isolation according to claim 1, characterized in that: The front fulcrum rotation structure (7) and the rear fulcrum rotation structure (9) both comprise a rotation structure housing (12), an elastic ring damping structure (13) and bearings, the high and low pressure rotating shafts pass through the bearings, the bearings are arranged inside the elastic ring damping structure, and the elastic ring damping structure (13) is arranged inside the rotation structure housing (12).

3. The turbine inter-stage multi-support common load-bearing structure with high vibration isolation according to claim 2, characterized in that: A second welding point (32) is provided on the high-pressure turbine side of the rotating structure housing of the front support rotating structure (7), and the second welding point (32) is connected to the high-pressure turbine rear support (8) via a first brush seal structure (33); a third welding point (34) is provided on the low-pressure turbine side of the bearing seat body (101), and the third welding point (34) is connected to the low-pressure turbine rear support (10) via a second brush seal structure (35).

4. The turbine inter-stage multi-support common load-bearing structure with high vibration isolation according to claim 1, characterized in that: A reinforcing rib (25) is provided in the first folding-type bearing cone shell (14); a dry friction damping shock absorbing structure (21) is provided in the second folding-type bearing cone shell (15), and the dry friction damping shock absorbing structure (21) includes a vibration-absorbing energy-absorbing spring piece (22), one end of the vibration-absorbing energy-absorbing spring piece (22) is connected to the second folding-type bearing cone shell (15), and the other end is a free end, and the vibration-absorbing energy-absorbing spring piece (22) contacts the surface of the second folding-type bearing cone shell (15) to form a dry friction contact surface (23); a groove structure is provided on the side of the first comb tooth structure (17) away from the first folding-type bearing cone shell (14), and one end of the dry friction spring piece (24) is installed in the groove structure, and the other end contacts the outer wall of the first comb tooth structure (17) outside the groove structure.

5. The turbine inter-stage multi-support common load-bearing structure with high vibration isolation according to claim 1, characterized in that: A step structure is provided on the side of the second sealing bushing (20) that contacts the second comb tooth structure (18).

6. The turbine interstage multi-support common load-bearing structure with high vibration isolation according to claim 1, characterized in that: The bearing seat body (101) is provided with a first flange mounting edge (31) and a second flange mounting edge (26), the first flange mounting edge (31) is connected to the load-bearing drum (2) through a first flange bolt connection structure (27), and the second flange mounting edge (26) is connected to the first fold-back load-bearing cone shell (14) through a second flange bolt connection structure (28), and a first welding point (29) is provided on the bearing seat body (101), which is connected to the second fold-back load-bearing cone shell (15) through the first welding point (29); the fold-back deflector mounting edge (11) is connected to the turbine interstage casing (6) through a third flange bolt connection structure (30).

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