Method for designing a multifunctional interstage support structure for a counter-rotating turbine and support structure

Abstract

The application belongs to the technical field of small gas turbine engine, and discloses a multifunctional interstage support structure design method and support structure for counter-rotating turbine. The design method comprises the following steps: designing an overall technical scheme; designing a load-bearing base; designing a variable stiffness force transmission frame; designing an equal mass wide frequency load-bearing mounting seat; and designing a double-bearing multi-pipeline and damping vibration integrated structure. The multifunctional interstage support structure for counter-rotating turbine changes the support structure form and optimizes the force transmission path; changes the stiffness of the support mechanism, improves the damping effect and anti-deformation capacity of the support structure through the design of elastic damping and other measures; arranges the double-bearing multi-pipeline and damping vibration integrated structure through the double-bearing seat shared support structure; realizes the double-bearing multi-pipeline and damping vibration integration through the arrangement of the lubricating oil inlet pipeline in the support structure. The multifunctional interstage support structure for counter-rotating turbine can meet the turbine interstage support design requirements of the high-speed rotor system of the small gas turbine engine and has engineering practical value.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of small gas turbine engines, and particularly relates to a multifunctional inter-stage support structure design method and support structure for a counter-rotating turbine. BACKGROUND

[0002] The turbine support structure is one of the key supports of an aero-engine, is a key load-bearing mechanism of turbine components, and bears all radial loads and part of axial loads, bending and torsional loads, and asymmetric impact loads. The commonly used turbine rear support structure is too long in axial dimension and too heavy in weight, the newly developed turbine inter-stage support structure shortens the axial length of the turbine, reduces the number of parts, optimizes the load-bearing and force transmission paths, and reduces the vibration coupling between rotors, and has the technical advantages of simple structure, light weight, high efficiency, and easy maintenance. However, due to the opposite rotation directions of the high-pressure rotor and the low-pressure rotor of the counter-rotating turbine, the relative rotation speed of the two rotors is doubled, which brings great challenges to the safe, stable and reliable operation of the counter-rotating rotor.

[0003] Therefore, it is necessary to develop a multifunctional inter-stage support structure design method and support structure for a counter-rotating turbine to improve the stability and reliability of the counter-rotating turbine rotor. SUMMARY

[0004] One of the technical problems to be solved by the application is to develop a multifunctional inter-stage support structure design method for a counter-rotating turbine, and another technical problem to be solved by the application is to develop a multifunctional inter-stage support structure for a counter-rotating turbine to overcome the defects of the prior art.

[0005] The multifunctional inter-stage support structure design method for a counter-rotating turbine comprises the following steps:

[0006] S10. Designing an overall technical scheme;

[0007] An integrated design of equal mass distribution, variable stiffness, double elastic damping and wide frequency is adopted;

[0008] S20. Designing a load-bearing base;

[0009] The variable stiffness force transmission frame, the equal mass wide frequency load-bearing mounting seat, and the double-bearing multi-pipeline and damping vibration reduction integrated structure are integrated in the load-bearing base, and the load-bearing base bears the radial force and axial force of the multifunctional inter-stage support structure for a counter-rotating turbine to meet the nonlinear mechanics design requirements of strength stiffness, damping vibration reduction coefficient and bearing capacity;

[0010] S30. Designing a variable stiffness force transmission frame;

[0011] The variable rigidity force transmission frame adopts a multi-layered casing frame structure, double-layered outer casings and elliptical support plates intersecting at 120 degrees pass through the flow channel and are spliced into a whole ring with the inner bearing casing;

[0012] S40. Design an equal-mass wide-frequency bearing mounting seat;

[0013] The equal-mass wide-frequency bearing mounting seat is arranged with a layered variable geometry cross-section equal-mass sealing body, double bearing support body, double damping damper and oil nozzle through the oil inlet and oil return system in the variable rigidity force transmission frame.

[0014] S50. Design a double-bearing multi-pipeline and damping vibration integrated structure;

[0015] The oil inlet and oil return system is arranged in the variable rigidity force transmission frame, and the double-bearing multi-pipeline and damping vibration integrated structure is designed in the front and rear inner annular surfaces of the equal-mass wide-frequency bearing mounting seat.

[0016] The multi-functional inter-stage support structure for the counter-rotating turbine is composed of a bearing base, a variable rigidity force transmission frame, an equal-mass wide-frequency bearing mounting seat and a double-bearing multi-pipeline and damping vibration integrated structure;

[0017] The variable rigidity force transmission frame adopts a multi-layered casing frame structure, double-layered outer casings and elliptical support plates intersecting at 120 degrees pass through the flow channel and are spliced into a whole ring with the inner bearing casing, so as to meet the requirement of a rigidity coefficient of 5x10e 7 N / m, and the oil inlet pipeline of the oil inlet and oil return pipeline is arranged above the elliptical support plate, and the oil return pipeline of the oil inlet and oil return pipeline is arranged below the elliptical support plate;

[0018] The equal-mass wide-frequency bearing mounting seat is segmented by the web plate, and the main body of the equal-mass wide-frequency bearing mounting seat is designed as a front bearing seat and a rear bearing seat with equal mass, and the front six natural frequencies of the equal-mass wide-frequency bearing mounting seat in different cross-sections are in the range of 0-300 Hz;

[0019] The double-bearing multi-pipeline and damping vibration integrated structure is sequentially arranged with region I and region II in front of and behind the inner cylindrical surface of the equal-mass wide-frequency bearing mounting seat, and is respectively provided with a front sealing body and a rear sealing body, a front roller bearing and a rear roller bearing, and a front damping damper and a rear damping damper, which are positioned radially through the cylindrical surface and axially constrained and limited by the baffle and the lock block.

[0020] Further, the force bearing matrix is the basis of the multifunctional interstage support structure of the counter-rotating turbine, which is composed of a variable stiffness force transmission frame, an equal mass wide frequency force bearing mount, and a two-bearing multi-pipeline and damping vibration integrated structure; the variable stiffness force transmission frame and the equal mass wide frequency force bearing mount are connected and limited by 12 M8 precision bolts of the axial I rear mounting edge, are tightly fitted and centered in the cylindrical surface I in the radial direction, and are sealed and assisted in positioning by the face I and face II in the front end face.

[0021] Further, the variable stiffness force transmission frame is a multi-layer casing frame structure, which is composed of a double-layer outer casing and an elliptical support plate; the double-layer outer casing and the elliptical support plate are limited and fixed by the flange surface axial II, are installed and radially centered by the cylindrical surface II, and are provided with an axial gap L as a matching gap for thermal expansion elongation; the double-layer outer casing rear end is designed with a boss and a pipe hole, which are tightly fitted with the end face of the boss on the double-layer outer casing through the horizontal positioning surface on the pipeline mount to install and fix the lubricating oil inlet and return pipeline; the elliptical support plate is composed of an outer flow channel surface, a support plate body, and an inner flow channel surface, the support plate body is radially elliptical, circumferentially three are distributed at 120°, and a through hole with a diameter ΦR is arranged in the middle of the support plate body above and below.

[0022] Further, the equal mass wide frequency force bearing mount is composed of a web, a front force bearing, and a rear force bearing; two lubricating oil pipe installation holes are designed on the front force bearing in the circumferential direction, a front roller bearing is arranged below the mass center of the front force bearing, and a rear roller bearing is arranged below the mass center of the rear force bearing, the two ends of the front roller bearing and the rear roller bearing are respectively axially limited by the baffle and the lock block; the vertical positioning surface of the baffle and the inclined surface of the rear force bearing are provided with a frequency adjustment material taking area; the baffle and the front force bearing are fixed by bolts in the cylindrical surface I.

[0023] Further, the double-bearing multi-pipeline and damping vibration integrated structure is composed of a lubricating oil inlet and return pipeline, a pipeline mounting seat, a front sealing sealing body, a rear sealing sealing body, a front roller bearing, a rear roller bearing, a front damping vibration damper and a rear damping vibration damper; wherein the inner diameter of the lubricating oil inlet and return pipeline is z, the inner cavity of the lubricating oil inlet and return pipeline is communicated with the lubricating oil flow path I and the lubricating oil flow path II, and then the lubricating oil flow path I and the lubricating oil flow path II are sprayed to supply oil to the front roller bearing and the rear roller bearing after passing through the nozzle to reduce pressure and increase speed; the front sealing sealing body and the rear sealing sealing body adopt a double-layer graphite sealing structure and are compactly pressed by end face compression springs; the front damping vibration damper and the rear damping vibration damper are in contact with the load-bearing mounting seat through eight equidistant convex posts with a width of 5mm arranged on the inner and outer ring surfaces in the circumferential direction; the outer ring surface I of the front damping vibration damper and the outer ring surface II of the rear damping vibration damper are in contact with the load-bearing mounting seat through a clearance cylindrical surface with a width of 0.01mm-0.05mm; the inner ring surface I of the front damping vibration damper is in contact with the outer bushing of the front roller bearing through a clearance cylindrical surface with a width of 0.01mm-0.05mm; the inner ring surface II of the rear damping vibration damper is in contact with the outer bushing of the rear roller bearing through a clearance cylindrical surface with a width of 0.01mm-0.05mm; and the front damping vibration damper and the rear damping vibration damper are allowed to deform in the radial direction during work to reduce and eliminate impact force, thereby playing a double-sided dynamic damping vibration damping role.

[0024] The multifunctional inter-stage supporting structure for counter-rotating turbines of the present application changes the supporting structure form and optimizes the force transmission path; changes the rigidity of the supporting mechanism and improves the damping effect and anti-deformation ability of the supporting structure through design of elastic damping and other measures; guarantees the isolation of vibration signals between the supporting points, reduces the coupling response of vibration between the high-pressure and low-pressure rotors, and reduces the vibration response of the rotors through the double-bearing seat shared supporting structure and the arrangement of the double-bearing multi-pipeline and damping vibration integrated structure; and realizes the double-bearing multi-pipeline and damping vibration integration through the arrangement of the lubricating oil inlet pipeline in the supporting structure and the arrangement of the oil return groove and the oil injection nozzle directly below the supporting structure.

[0025] The design method of the multifunctional inter-stage supporting structure for counter-rotating turbines of the present application adopts a multifunctional variable-rigidity strong-damping inter-stage supporting structure and arranges a double-bearing multi-lubricating oil pipeline system, thereby overcoming the technical constraints of the size and geometric space of the supporting structure, reducing the coupling response of vibration between the high-pressure and low-pressure rotors, solving the technical problems of equal mass distribution, variable rigidity, double elastic damping, wide frequency, multifunctional and low-guide counter-rotating turbine integration design, and obtaining a supporting structure with various functions, compact geometric space, good strength and rigidity, high working stability, and convenient disassembly, maintenance and repair, which can meet the turbine inter-stage supporting requirements of small gas turbine engines for high-speed rotor systems.

[0026] In short, the composite supporting casing for air intake and exhaust and the design method thereof of the present application can meet the turbine inter-stage supporting design requirements of small gas turbine engines for high-speed rotor systems and have engineering practical value. Attached Figure Description

[0027] Figure 1 A flowchart illustrating the design method of the multifunctional interstage support structure for a counter-rotating turbine according to the present invention;

[0028] Figure 2 This is a schematic diagram of the multifunctional interstage support structure for a counter-rotating turbine according to the present invention.

[0029] Figure 3 This is a schematic diagram of the variable stiffness force transmission frame in this invention;

[0030] Figure 4 This is a schematic diagram of the double-layer outer casing of the variable stiffness force transmission frame in this invention.

[0031] Figure 5 This is a schematic diagram of the elliptical support plate structure of the variable stiffness force transmission frame in this invention.

[0032] Figure 6 This is a schematic diagram of the equal-mass wide-frequency load-bearing mounting base structure in this invention;

[0033] Figure 7 This is a schematic diagram of the lubricating oil inlet and return pipelines of the dual-bearing multi-pipeline and damping vibration reduction integrated structure in this invention.

[0034] Figure 8 This is a schematic diagram of the integrated structure of dual bearings, multiple pipelines, and damping vibration reduction in this invention.

[0035] In the diagram, 1. Load-bearing base; 2. Variable stiffness force transmission frame; 3. Equal mass wide frequency load-bearing mounting base; 4. Integrated structure of dual bearings, multi-pipeline, and damping vibration reduction.

[0036] 201. Double-layer outer casing; 202. Elliptical support plate;

[0037] 2021. Outer flow channel surface; 2022. Support plate body; 2023. Inner flow channel surface;

[0038] 301. Web plate; 302. Front bearing seat; 303. Rear bearing seat; 304. Baffle plate; 305. Locking block;

[0039] 401. Lubricating oil inlet and return lines; 402. Line mounting bracket; 403. Front sealing seal; 404. Front damping shock absorber; 405. Rear sealing seal; 406. Rear damping shock absorber;

[0040] 501. Surface I; 502. Surface II; 503. Axial I; 504. Cylindrical Surface I; 505. Region I; 506. Region II; 507. Axial II; 508. Boss; 509. Horizontal positioning surface; 510. Cylindrical Surface II; 511. Pipe hole; 512. Bolt; 513. Oil pipe mounting hole; 514. Vertical positioning surface; 515. Inclined surface; 516. Front roller bearing; 517. Rear roller bearing; 518. Outer ring surface I; 519. Inner ring surface I; 520. Outer ring surface II; 521. Inner ring surface II; 522. Oil flow path I; 523. Oil flow path II; 524. Nozzle. Detailed Implementation

[0041] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0042] Example: Figure 1 As shown, the design method for a multi-functional interstage support structure for a counter-rotating turbine in this embodiment includes the following steps:

[0043] S10. Design the overall technical solution;

[0044] It adopts an integrated design with equal mass distribution, variable stiffness, dual elastic damping, and wide frequency range;

[0045] S20. Design of load-bearing base 1;

[0046] The variable stiffness force transmission frame 2, the equal mass wide frequency load-bearing mounting base 3, and the dual-bearing multi-pipeline and damping vibration reduction integrated structure 4 are integrated into the load-bearing base 1. The load-bearing base 1 bears the radial and axial forces of the multi-functional interstage support structure used for the counter-rotating turbine, so as to meet the nonlinear mechanical design requirements such as strength stiffness, damping vibration reduction coefficient and load-bearing capacity.

[0047] S30. Design of a variable stiffness force transmission frame 2;

[0048] The variable stiffness force transmission frame 2 adopts a multi-layer casing frame structure. The double-layer outer casing 201 and the elliptical support plate 202 at 120° to each other pass through the flow channel and are then spliced ​​with the inner load-bearing casing to form a complete ring.

[0049] S40. Design of equal-mass, wide-frequency load-bearing mounting base 3;

[0050] The equal-mass, wide-frequency load-bearing mounting base 3 is sealed with a layered variable geometric cross-section, a double-bearing support, a double-damping damper, and a lubricating oil injector through a layered variable geometric cross-section and equal-center-of-mass arrangement.

[0051] S50. Design of a dual-bearing, multi-pipeline, and damping vibration reduction integrated structure 4;

[0052] The lubricating oil inlet and return system is arranged in the variable stiffness force transmission frame 2. The front inner ring and rear inner ring of the equal mass wide frequency load-bearing mounting base 3 are designed in layers to form a dual bearing multi-pipeline integrated structure with damping and vibration reduction 4.

[0053] like Figures 2-8 As shown, the multi-functional interstage support structure for counter-rotating turbines in this embodiment consists of a load-bearing base 1, a variable stiffness force transmission frame 2, an equal mass wide frequency load-bearing mounting base 3, and a dual-bearing multi-pipeline integrated structure with damping and vibration reduction 4.

[0054] The variable stiffness force transmission frame 2 adopts a multi-layer casing frame structure. The double-layer outer casing 201 and the elliptical support plates 202 at 120° to each other are spliced ​​together through the flow channel to form a complete ring to meet the stiffness coefficient of 5×10e. 7 The requirement of N / m is met, and the oil inlet pipe of the lubricating oil inlet and return pipe 401 is arranged directly above the elliptical support plate 202, and the oil return pipe of the lubricating oil inlet and return pipe 401 is arranged directly below the elliptical support plate 202.

[0055] The equal-mass wide-frequency load-bearing mounting base 3 uses the web plate 301 as the dividing area, and divides the main body of the equal-mass wide-frequency load-bearing mounting base 3 into sections and designs them as front load-bearing base 302 and rear load-bearing base 303 with equal mass, and meets the requirement that the first six natural frequencies of the equal-mass wide-frequency load-bearing mounting base 3 in different sections are in the range of 0 to 300 Hz.

[0056] The dual-bearing, multi-pipeline, and damping vibration reduction integrated structure 4 is constructed by sequentially setting region I 505 and region II 506 on the front and back of the inner cylindrical surface of the equal-mass, wide-frequency load-bearing mounting base 3. Region I 505 and region II 506 are respectively equipped with a front sealing body 403 and a rear sealing body 405, a front roller bearing 516 and a rear roller bearing 517, a front damping vibration damper 404 and a rear damping vibration damper 406. The structure is radially positioned by the cylindrical surface and axially constrained and limited by a baffle 304 and a locking block 305.

[0057] Furthermore, the load-bearing base 1 is the foundation of the multi-functional interstage support structure for the counter-rotating turbine, consisting of a variable stiffness force transmission frame 2, an equal mass wide-frequency load-bearing mounting base 3, and a dual-bearing multi-pipeline integrated structure with damping and vibration reduction 4. The variable stiffness force transmission frame 2 and the equal mass wide-frequency load-bearing mounting base 3 are connected and limited by 12 M8 precision bolts on the rear mounting edge axial I503, and are radially centered by a stop on the cylindrical surface I504, and are sealed and auxiliary positioned on the front end face by surfaces I501 and II502.

[0058] Furthermore, the variable stiffness force transmission frame 2 is a multi-layer casing frame structure, consisting of a double-layer outer casing 201 and an elliptical support plate 202; the double-layer outer casing 201 and the elliptical support plate 202 are axially limited and fixed by flange face II 507, installed and radially centered by cylindrical face II 510, and an axial clearance L is provided as a matching clearance for thermal expansion elongation; the rear end of the double-layer outer casing 201 is designed with a boss 508 and a pipe hole 511, through which pipelines... The horizontal positioning surface 509 on the mounting base 402 is tightly fitted with the end face of the boss 508 on the double-layer outer casing 201 to install and fix the lubricating oil inlet and return oil pipeline 401; the elliptical support plate 202 is composed of an outer flow channel surface 2021, a support plate body 2022 and an inner flow channel surface 2023. The support plate body 2022 is elliptical in the radial direction and three are distributed at 120° intervals in the circumferential direction. A through hole with a diameter of ΦR is arranged in the middle of the support plate body 2022 at the top and bottom.

[0059] Furthermore, the equal-mass wide-frequency load-bearing mounting base 3 is composed of a web plate 301, a front load-bearing base 302, and a rear load-bearing base 303. Two lubricating pipe mounting holes 513 are designed circumferentially on the front load-bearing base 302. A front roller bearing 516 is arranged directly below the center of mass of the front load-bearing base 302, and a rear roller bearing 517 is arranged directly below the center of mass of the rear load-bearing base 303. The two ends of the front roller bearing 516 and the rear roller bearing 517 are axially limited by a baffle 304 and a locking block 305, respectively. Frequency tuning material sampling areas are provided on the vertical positioning surface 514 of the baffle 304 and the inclined surface 515 of the rear load-bearing base 303. The baffle 304 and the front load-bearing base 302 are fixed on the cylindrical surface I 504 by bolts 512.

[0060] Furthermore, the dual-bearing multi-pipeline integrated damping and vibration reduction structure 4 comprises an oil inlet / return pipeline 401, a pipeline mounting base 402, a front sealing body 403, a rear sealing body 405, a front roller bearing 516, a rear roller bearing 517, a front damping vibration damper 404, and a rear damping vibration damper 406. The inner diameter of the oil inlet / return pipeline 401 is z. The inner cavity of the oil inlet / return pipeline 401 is connected to oil flow path I 522 and oil flow path II 523. After passing through a variable cross-section nozzle 524 for pressure reduction and acceleration, oil is injected to supply oil to the front roller bearing 516 and the rear roller bearing 517. The front sealing body 403 and the rear sealing body 405 adopt a double-layer graphite sealing structure and are compacted by end-face compression springs. The front damping vibration damper 404 and the rear damping vibration damper 406 are connected via… Eight equally spaced, 5mm wide bosses are arranged circumferentially on the inner and outer annular surfaces. The outer annular surface I518 of the front damping damper 404 and the outer annular surface II520 of the rear damping damper 406 make contact with the load-bearing mounting seat 3 with a gap cylindrical surface boss with a width of 0.01mm to 0.05mm. The inner annular surface I519 of the front damping damper 404 makes contact with the outer bushing of the front roller bearing 516 with a gap cylindrical surface boss with a width of 0.01mm to 0.05mm. The inner annular surface II521 of the rear damping damper 406 makes contact with the outer bushing of the rear roller bearing 517 with a gap cylindrical surface boss with a width of 0.01mm to 0.05mm. During operation, the front damping damper 404 and the rear damping damper 406 are allowed to deform radially to reduce and eliminate impact force, thus playing the role of double-sided dynamic damping and vibration reduction.

[0061] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. For those skilled in the art, all features disclosed in the present invention, or all steps in all methods or processes disclosed, except for mutually exclusive features and / or steps, can be combined in any way without departing from the principles of the present invention. The present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A design method for a multifunctional interstage support structure for counter-rotating turbines, characterized in that, Includes the following steps: S10. Design the overall technical solution; The design adopts an integrated approach with equal mass distribution, variable stiffness, dual elastic damping, and wide frequency. The multi-functional interstage support structure for the counter-rotating turbine consists of a load-bearing base (1), a variable stiffness force transmission frame (2), an equal mass wide frequency load-bearing mounting base (3), and a dual-bearing multi-pipeline integrated structure with damping and vibration reduction (4). S20. Design of load-bearing base (1); The variable stiffness force transmission frame (2), the equal mass wide frequency load-bearing mounting base (3), and the dual bearing multi-pipeline and damping vibration reduction integrated structure (4) are integrated into the load-bearing base (1). The load-bearing base (1) bears the radial and axial forces of the multi-functional interstage support structure used for the counter-rotating turbine, so as to meet the nonlinear mechanical design requirements including strength, stiffness, damping vibration reduction coefficient and bearing capacity. S30. Design of variable stiffness force transmission frame (2); The variable stiffness force transmission frame (2) adopts a multi-layer casing frame structure. The design features a double-layer outer casing (201) and an elliptical support plate (202) at 120° to each other passing through the flow channel. It is then spliced ​​with the inner load-bearing casing to form a complete ring to meet the stiffness coefficient of 5×10e. 7 The requirement of N / m is met, and the oil inlet pipe of the lubricating oil inlet and return pipe (401) is arranged directly above the elliptical support plate (202), and the oil return pipe of the lubricating oil inlet and return pipe (401) is arranged directly below the elliptical support plate (202). S40. Design of a wide-frequency load-bearing mounting base of equal mass (3) The equal-mass wide-frequency load-bearing mounting base (3) is sealed by a layered variable geometric cross-section equal-mass arrangement of a sealing body, a double bearing support, a double damping damper, and a lubricating oil injector. The equal mass wide frequency load-bearing mounting base (3) is divided into sections by the web plate (301) and designed as front load-bearing base (302) and rear load-bearing base (303) with equal mass, and meets the requirement that the first six natural frequencies of the equal mass wide frequency load-bearing mounting base (3) are in the range of 0 to 300 Hz in different sections. S50. Design a dual-bearing multi-pipeline integrated structure with damping and vibration reduction (4). The lubricating oil inlet and return system is arranged in the variable stiffness force transmission frame (2), and the double bearing seat and damping vibration reduction integrated structure (4) are designed in layers on the front inner ring surface and rear inner ring surface of the equal mass wide frequency load-bearing mounting seat (3). The dual-bearing multi-pipeline integrated structure with damping and vibration reduction (4) is provided with M region and N region in sequence on the inner cylindrical surface of the equal mass wide frequency load-bearing mounting base (3). In the M region and N region, a front sealing body (403) and a rear sealing body (405), a front roller bearing O1 and a rear roller bearing O2, a front damping damper (404) and a rear damping damper (406) are respectively provided. The radial positioning is achieved through the cylindrical surface, and the axial constraint is achieved through the baffle (304) and the locking block (305).

2. A multifunctional interstage support structure for a counter-rotating turbine, designed using the multifunctional interstage support structure design method for a counter-rotating turbine as described in claim 1, characterized in that, The load-bearing base (1) is the foundation of the multi-functional interstage support structure for the counter-rotating turbine. It consists of a variable stiffness force transmission frame (2), an equal mass wide frequency load-bearing mounting base (3), and a dual-bearing multi-pipeline and damping vibration reduction integrated structure (4). The variable stiffness force transmission frame (2) and the equal mass wide frequency load-bearing mounting base (3) are connected and limited by 12 M8 precision bolts in the rear mounting edge G axial direction. They are radially centered by a stop on the H cylindrical surface and sealed and auxiliary positioned by surfaces E and F on the front end face.

3. The multifunctional interstage support structure for a counter-rotating turbine according to claim 2, characterized in that, The variable stiffness force transmission frame (2) is a multi-layer casing frame structure, consisting of a double-layer outer casing (201) and an elliptical support plate (202); the double-layer outer casing (201) and the elliptical support plate (202) are axially limited and fixed by flange surface A, installed and radially centered by cylindrical surface B, and an axial clearance L is set as a matching clearance for thermal expansion elongation; the rear end of the double-layer outer casing (201) is designed with a boss J1 and a pipe hole C, and is connected by a pipe mounting seat (402). The J2 end face on the double-layer outer casing (201) is tightly fitted with the J1 end face of the boss to install and fix the lubricating oil inlet and outlet pipeline (401); the elliptical support plate (202) is composed of an outer flow channel surface (2021), a support plate body (2022) and an inner flow channel surface (2023). The support plate body (2022) is elliptical in the radial direction and three are distributed at 120° to each other in the circumferential direction. A through hole with a diameter of ΦR is arranged in the middle of the support plate body (2022) directly above and directly below.

4. The multifunctional interstage support structure for a counter-rotating turbine according to claim 3, characterized in that, The equal-mass wide-frequency load-bearing mounting base (3) consists of a web plate (301), a front load-bearing base (302), and a rear load-bearing base (303). Two lubricating pipe mounting holes D are designed circumferentially on the front load-bearing base (302). A front roller bearing O1 is arranged directly below the center of mass of the front load-bearing base (302), and a rear roller bearing O2 is arranged directly below the center of mass of the rear load-bearing base (303). The two ends of the front roller bearing O1 and the rear roller bearing O2 are axially limited by a baffle (304) and a locking block (305), respectively. Frequency tuning sampling areas are set at W1 of the baffle (304) and W2 of the rear load-bearing base (303). The baffle (304) and the front load-bearing base (302) are fixed on the H cylindrical surface by bolts S.

5. The multifunctional interstage support structure for a counter-rotating turbine according to claim 4, characterized in that, The dual-bearing multi-pipeline integrated damping and vibration reduction structure (4) consists of an oil inlet and return pipeline (401), a pipeline mounting base (402), a front sealing body (403), a rear sealing body (405), a front roller bearing O1, a rear roller bearing O2, a front damping vibration damper (404), and a rear damping vibration damper (406). The inner diameter of the oil inlet and return pipeline (401) is D. The inner cavity of the oil inlet and return pipeline (401) is connected to the oil flow path V1 and the oil flow path V2. After passing through the variable cross-section nozzle V3 to reduce pressure and increase speed, it sprays oil to supply the front roller bearing O1 and the rear roller bearing O2. The front sealing body (403) and the rear sealing body (405) adopt a double-layer graphite sealing structure and are sealed by end face springs. Compact and tighten; the front damping damper (404) and the rear damping damper (406) are connected by eight equally spaced, 5mm wide bosses arranged circumferentially on the inner and outer ring surfaces. The outer ring surface K1 of the front damping damper (404) and the outer ring surface P1 of the rear damping damper (406) are in contact with the load-bearing mounting seat (3) with a gap cylindrical surface fitting boss with a width of 0.01mm to 0.05mm. The inner ring surface K2 and the inner ring surface P2 are in contact with the outer bushings of the front roller bearing O1 and the rear roller bearing O2 with a gap cylindrical surface fitting boss with a width of 0.01mm to 0.05mm, respectively. During operation, the front damping damper (404) and the rear damping damper (406) are allowed to deform radially to reduce and eliminate the impact force, thereby playing the role of double-sided dynamic damping and vibration reduction.

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