Rigidity-variable elastic squirrel cage supporting seat and supporting structure

Abstract

An elastic squirrel cage supporting seat with variable rigidity and a supporting structure belong to the field of gas turbine rotors, the elastic squirrel cage supporting seat comprises a mounting edge and a sleeve, the mounting edge and the sleeve are of an integrated cantilever type structure, and the elastic squirrel cage supporting seat further comprises a damping bolt; the sleeve is of a stepped cylindrical structure, the outer diameter of the sleeve from the installation edge end to the free end is gradually reduced, and the rigidity of the elastic mouse cage supporting seat is adjusted through a damping bolt capable of being screwed into the threaded through hole. The supporting structure comprises a bearing seat, a bearing end cover, a bearing positioning ring, a rotating shaft, a bearing outer ring gland, an elastic supporting bearing, a bearing compression nut and the elastic mouse cage supporting seat; the bearing outer ring gland is installed at the position of an inner step of the elastic squirrel cage supporting seat, an inner ring of the elastic supporting bearing is installed on a shaft neck of the rotating shaft, and the inner diameter of a barrel with the smallest outer diameter of the elastic squirrel cage supporting seat is matched with the outer diameter of the outer ring of the elastic supporting bearing. The method is simple in adjustment mode, convenient to operate and suitable for being used in the fields of gas turbine engine rotors and the like.

Description

Technical Field

[0001] The invention relates to a squirrel cage and a supporting structure, in particular to an elastic squirrel cage supporting seat with variable stiffness and a supporting structure, belonging to the field of gas turbine rotors. Background Art

[0002] In the design of gas turbine rotors, squirrel cage structures are often used as part of elastic supports. Elastic supports and squeeze film damper technology for high-speed rotors in the field of aeroengines are commonly used means of reducing engine rotor vibration. Aeroengine rotors generally have high speeds, and most of them are high-speed rotors that operate across criticality. The elastically supported bearings modulate the rotor's natural frequency to make the working speed range of high-speed rotors as wide as possible. According to rotor dynamics theory, the mass, stiffness and damping of the rotor system are the main reasons affecting the rotor dynamics. Adjusting rotor characteristics such as critical speed by adjusting parameters such as the rotor's own mass and stiffness will limit the strength design of the rotor, and the design optimization and adjustment cycle is long. The adjustment of the support stiffness and damping at the rotor's support bearing is relatively convenient. Therefore, in engineering, changing the stiffness and damping of the support rotor can adjust the vibration characteristics of the rotor, such as the critical speed and unbalance vibration response. By adjusting the stiffness and damping of the elastic support, the critical speed can be adjusted, the vibration energy of the rotor-support system can be absorbed, and a certain degree of vibration reduction can be achieved.

[0003] During the operation of a gas turbine, the rotor usually maintains a relatively high speed, so vibration suppression is particularly important. Excessive vibration will seriously affect the stability, safety and service life of the system. At present, the damping and stiffness of the common squirrel cage elastic support structure are generally fixed when the structural design and external conditions such as lubricating oil remain unchanged, and it is not universal. In actual use, due to design and processing deviations, the actual stiffness and damping values ​​often deviate from the design target values. In engineering, it is often necessary to adjust the stiffness and damping of the bearing support through experimental adjustments. When the parameters of the actual processed parts cannot meet the requirements, they need to be reprocessed, which prolongs the design cycle and increases the design cost. Therefore, the squirrel cage elastic support structure with variable damping and stiffness is of great research and application value. The advantage of the variable stiffness squirrel cage elastic support structure is that it can improve the universality of the application of the same basic design and meet the needs of related scientific research experiments. Some of the supporting parts such as the casing of an aircraft engine are designed with asymmetric shapes, which will lead to anisotropy in the stiffness of high-speed shafts such as the central cone transmission rod. In order to improve the running stability of the rotor, it is necessary to adjust the comprehensive support stiffness of the system by designing the stiffness anisotropy of the elastic support structure such as the rotor cage. CN109026207A-squirrel cage elastic support with stiffness gradient, discloses a cylindrical bearing mounting ring with a fixed ring and a plurality of through grooves on the cylinder wall, and changes the stiffness of the squirrel cage elastic support by adjusting the relative size of the cross-sectional area of ​​the two cage bars. The design mainly proposes a design method for squirrel cage elastic support. Changing the relative size of the cross-sectional area requires reprocessing the squirrel cage and reinstalling it, which is cumbersome and has a small range of adjustable stiffness.

[0004] CN101532540A-Squirrel cage elastic support and design method thereof, discloses a cantilever structure composed of a mounting edge and a sleeve, the mounting edge and the sleeve are an integrated structure, and is characterized in that a plurality of elliptical slots are opened on the sleeve to form a plurality of cage bars of different widths, the cage bars are cyclically symmetrically distributed on the sleeve, and the design variables are few, thereby improving the problem of stress concentration at the root of the cage bar in the prior art with rectangular holes, and realizing the optimized design of stiffness and stress.

[0005] CN111608749A-Radial stiffness adjustment device and method for squirrel cage elastic supporter, aircraft engine, relates to a squirrel cage elastic supporter stiffness adjustment device and method, the squirrel cage elastic supporter is fixed to a bracket, a rotating shaft and a shaft sleeve are arranged in the squirrel cage elastic supporter, the elastic supporter includes a plurality of squirrel cage elastic bars, an adjustment mechanism is in contact with the squirrel cage elastic bars, and can move axially along the squirrel cage elastic supporter to change the contact position with the squirrel cage elastic bars, the stiffness adjustment of the elastic support structure is isotropic, and the stiffness in a single direction cannot be differentially adjusted.

[0006] In summary, the existing squirrel cage structure has the problems of being unable to adjust stiffness anisotropically, having a small adjustable stiffness range and complicated operation steps, and the above problems need to be solved urgently. Summary of the invention

[0007] In order to overcome the shortcomings of the prior art, the present invention provides an elastic squirrel cage support seat and a support structure with variable stiffness. The stiffness of the device is changed by installing a damping bolt. The damping bolt is made of damping metal, and a damping link is added to achieve anisotropic adjustment of stiffness. Bolt mounting holes are designed at corresponding positions on the bearing seat. When installing and removing the damping bolt, it is not necessary to remove the entire squirrel cage. The operation is convenient, the support structure is simple, and a large range of stiffness changes can be achieved without changing the structure of other parts of the bearing seat.

[0008] An elastic squirrel cage support seat with variable stiffness comprises a mounting edge and a sleeve, wherein the mounting edge and the sleeve are an integrated cantilever structure, and is characterized in that: it also comprises a damping bolt; the sleeve is a stepped cylindrical structure, the outer diameter of the sleeve gradually decreases from the mounting edge end to the free end, and the sleeve has m circles of holes on the cylinder with the largest outer diameter, each circle has n threaded holes, and the n×m threaded holes are arranged in an array, and the stiffness of the elastic squirrel cage support seat is adjusted by the damping bolt that can be screwed into the threaded through hole.

[0009] A support structure comprises a bearing seat, a bearing end cover, a bearing positioning ring, a rotating shaft, a bearing outer ring pressure cover, an elastic support bearing, a bearing clamping nut and the elastic squirrel cage support seat; the elastic squirrel cage support seat is installed on one side of the bearing seat, the bearing outer ring pressure cover is installed on the inner step of the elastic squirrel cage support seat, the inner ring of the elastic support bearing is installed on the journal of the rotating shaft, the inner diameter of the cylinder with the smallest outer diameter of the elastic squirrel cage support seat is matched with the outer diameter of the outer ring of the elastic support bearing, the elastic support bearing is axially positioned by the bearing positioning ring, the bearing outer ring pressure cover and the bearing clamping nut, and the bearing end cover is installed on the other side of the bearing seat.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] The variable stiffness elastic squirrel cage support seat of the present application has threaded through holes evenly distributed thereon. The material distribution of the squirrel cage is changed by the tight fit of the threaded pair between the damping bolt and the bolt hole, thereby changing the stiffness matrix of the structure and achieving anisotropic adjustment of the stiffness of the device. The change in the arrangement of the bolt through holes (the number of hole rows and the spacing) is equivalent to the equivalent ribs of the squirrel cage structure, and the stiffness of the device can be adjusted over a large range by changing the length, width and position of the equivalent ribs. The damping bolt is made of damping metal, and a damping link is added. It has obvious effects on adjusting the critical speed of the rotor and controlling the vibration. It has a novel form, innovative functions, a simple adjustment method, and is easy to operate. It is suitable for use in gas turbine engine rotors and other fields.

[0012] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments: BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A schematic diagram of an elastic squirrel cage support with variable stiffness according to the present application;

[0014] Figure 2 A cross-sectional view of the elastic squirrel cage support with variable stiffness of the present application;

[0015] Figure 3 This is a structural diagram of the damping bolts being fully installed into the elastic squirrel cage support seat;

[0016] Figure 4 Schematic diagram of isotropically installing the damping bolt into the elastic squirrel cage support Figure 1 ;

[0017] Figure 5 Schematic diagram of isotropically installing the damping bolt into the elastic squirrel cage support Figure 2 ;

[0018] Figure 6 Schematic diagram of anisotropically mounted damping bolts in an elastic squirrel cage support;

[0019] Figure 7 Schematic diagram of a support structure with variable stiffness.

[0020] Figure numerals: 10, bearing seat, 11, mounting hole, 12, bolt mounting hole, 20, elastic squirrel cage support seat, 201, mounting edge, 202, sleeve, 21, threaded through hole, 30, bearing end cover, 40, bearing locating ring, 50, rotating shaft, 60, bearing outer ring pressure cover, 70, elastic support bearing, 80, bearing clamping nut. DETAILED DESCRIPTION

[0021] The embodiments of the technical solution of the present application will be described in detail below in conjunction with the accompanying drawings. Unless otherwise specified, the technical terms or scientific terms used in the present application are generally understood by those skilled in the art to which the present invention belongs.

[0022] Figure 1-Figure 2 The invention discloses an elastic squirrel cage support seat with variable stiffness, comprising a mounting edge 201 and a sleeve 202, wherein the mounting edge 201 and the sleeve 202 are an integral cantilever structure, and further comprising a damping bolt 22; the sleeve 202 is a stepped cylindrical structure, wherein the outer diameter of the sleeve 202 from the mounting edge end to the free end is gradually reduced, and the sleeve 202 has m circles of holes on the cylinder with the largest outer diameter, each circle has n threaded holes 21, and n×m threaded holes are arranged in an array, and the stiffness of the elastic squirrel cage support seat is adjusted by the damping bolt 22 that can be screwed into the threaded through hole 21. Where n and m are both positive integers greater than or equal to 1.

[0023] The elastic squirrel cage support seat has a plurality of threaded through holes 21 evenly distributed thereon, and the stiffness of the elastic squirrel cage support seat can be adjusted by installing and removing the damping bolts 22.

[0024] Further, Figure 3 This is the state where the damping bolts 22 are all installed in the elastic cage support seat, and at this time, the rigidity of the elastic cage support seat reaches the maximum.

[0025] Figure 4-Figure 5 Two other states of isotropically installed damping bolt 22 are shown, that is, isotropically installed in a centrosymmetric manner. Figure 4 It is shown that the damping bolts 22 are screwed into the threaded through holes 21 at intervals along the axial direction. Figure 5 It is shown that the damping bolts 22 are screwed into the threaded through holes 21 at intervals along the radial direction. These two states are only shown as examples. The arrangement of the damping bolts 22 can be changed at will during actual application.

[0026] Figure 6 The figure shows a state where the damping bolts 22 are anisotropically installed. The damping bolts 22 are arranged non-centrosymmetrically. At this time, the elastic squirrel cage support seat shows anisotropy of stiffness.

[0027] Based on the above-mentioned implementation scheme of the elastic cage support seat, a support structure is also provided, such as Figure 7 As shown, the support structure includes a bearing seat 10, a bearing end cover 30, a bearing positioning ring 40, a rotating shaft 50, a bearing outer ring pressure cover 60, an elastic support bearing 70, a bearing clamping nut 80 and an elastic squirrel cage support seat 20 as described in any of the above embodiments; the elastic squirrel cage support seat 20 is installed on one side of the bearing seat 10, the bearing outer ring pressure cover 60 is installed on the inner step of the elastic squirrel cage support seat 20, the inner ring of the elastic support bearing 70 is installed on the journal of the rotating shaft 50, the inner diameter of the cylinder with the smallest outer diameter of the elastic squirrel cage support seat 20 is matched with the outer diameter of the outer ring of the elastic support bearing 70, the elastic support bearing 70 is axially positioned by the bearing positioning ring 40, the bearing outer ring pressure cover 60 and the bearing clamping nut 80, and the bearing end cover 30 is installed on the other side of the bearing seat 10.

[0028] Specifically, first, the elastic cage support seat 20 realizes radial positioning through the cooperation between the outer diameter of the outer ring of the elastic support bearing 70 and its inner diameter. Its mounting flange is connected to the bearing seat 10 through fixing bolts, and the bearing outer ring pressure cover 60 is installed on the inner ring of the elastic cage support seat 20. The inner ring of the elastic support bearing 70 is installed on the mounting journal of the rotating shaft 50 according to a certain matching relationship to complete radial positioning, and its axial positioning is completed under the joint compression of the bearing positioning ring 40, the bearing outer ring pressure cover 60 and the bearing clamping nut 80, so that the elastic support bearing 70 is installed and positioned on the rotating shaft 50. The entire bearing seat 10 is connected to the main machine housing through the mounting hole 11, and the other end is sealed by the bearing end cover 30 and fixed to the bearing seat 10 by bolts, thereby completing the positioning and installation of the bearing seat body.

[0029] Figure 1 As shown, a number of threaded through holes 21 are evenly distributed on the elastic cage support seat 20. By installing and removing the damping bolts 22, the material distribution of the cage structure can be changed to adjust the stiffness of the device. Most traditional cage structures adopt the form of waist-shaped holes or ribs. The squirrel cage elastic support structure of the present invention makes the arrangement of the threaded through holes 21 equivalent to equivalent ribs. The change in the arrangement of the damping bolts 22 is equivalent to the change in the length, width and position of the equivalent ribs, thereby achieving the adjustment of the stiffness of the rotor support system without changing the main structure of the device. Figure 3 , n threaded holes 21 with a diameter of d are evenly distributed on the elastic cage support seat 20, and the angle between the initial threaded hole position and the horizontal center line is a°. There are m circles of threaded holes 21 evenly distributed in the axial direction with an interval of L. When all the damping bolts 22 are installed, the stiffness of the rotor support system reaches the maximum, refer to Figure 3 .

[0030] When the damping bolts 22 are installed according to 2n-1 on the radial circumference and m on the axial direction, the stiffness of the elastic cage support is isotropic. When the damping bolts 22 are installed according to n on the radial circumference and 2m-1 on the axial direction, the stiffness of the elastic cage support is still isotropic. Figure 4-Figure 5 As long as the position where the damping bolt 22 is installed is centrally symmetrical, the isotropy of the stiffness of the squirrel cage elastic support structure can be ensured.

[0031] When the damping bolts 22 are installed from the fifth position relative to the initial position on the radial circumference, and the m axial bolts are all installed into the threaded through holes 21, the stiffness of the elastic squirrel cage support seat at this time is anisotropic, referring to Figure 6 .

[0032] The above three installation conditions of the damping bolts 22 are only examples. The damping bolts 22 can be arranged arbitrarily as needed to achieve the purpose of adjusting the stiffness, and the adjustable range is relatively large. The damping bolts 22 on the elastic squirrel cage support seat 20 can be quickly installed or removed through the bolt installation holes 12 on the bearing seat 10, avoiding repeated disassembly and assembly, making the operation more convenient. The damping bolts 22 are made of damping metal, which adds a damping link to the system while adjusting the stiffness, and has obvious effects on regulating the critical speed of the rotor and controlling vibration, improving the service life and fatigue performance of the bearing, and optimizing the adaptability and dynamic characteristics of the system.

[0033] The present invention has been disclosed as above with preferred implementation cases, but it is not intended to limit the present application. Any technician familiar with the profession can make slight changes or modifications to equivalent implementation cases with equivalent changes by using the above-disclosed structures and technical contents without departing from the scope of the technical solution of the present application, which still fall within the scope of the technical solution of the present application.

Claims

1. An elastic squirrel cage support with variable stiffness, comprising a mounting edge (201) and a sleeve (202), wherein the mounting edge (201) and the sleeve (202) are an integrated cantilever structure, characterized in that: It also includes a damping bolt (22); the sleeve (202) is a stepped cylindrical structure, the outer diameter of the sleeve (202) gradually decreases from the mounting edge end to the free end, the sleeve (202) has m circles of holes on the cylinder with the largest outer diameter, each circle has n threaded holes (21), and the n×m threaded holes are arranged in an array, and the stiffness of the elastic squirrel cage support seat is adjusted by the damping bolt (22) that can be screwed into the threaded through hole (21).

2. The variable stiffness elastic cage support according to claim 1, characterized in that: The damping bolt (22) is made of damping metal material.

3. The variable stiffness elastic cage support according to claim 1, characterized in that: The damping bolts (22) are screwed into the threaded through holes (21) at intervals along the axial direction.

4. The variable stiffness elastic cage support according to claim 1, characterized in that: The damping bolts (22) are screwed into the threaded through holes (21) at intervals in the radial direction.

5. The variable stiffness elastic cage support according to claim 1, characterized in that: The damping bolts (22) are arranged in a non-centrosymmetrical manner.

6. A support structure, characterized in that: The support structure comprises a bearing seat (10), a bearing end cover (30), a bearing positioning ring (40), a rotating shaft (50), a bearing outer ring pressure cover (60), an elastic support bearing (70), a bearing clamping nut (80) and an elastic squirrel cage support seat (20) as claimed in any one of claims 1 to 5; the elastic squirrel cage support seat 20 is installed on one side of the bearing seat (10), the bearing outer ring pressure cover (60) is installed on the inner step of the elastic squirrel cage support seat (20), the inner ring of the elastic support bearing (70) is installed on the journal of the rotating shaft (50), the inner diameter of the cylinder with the smallest outer diameter of the elastic squirrel cage support seat (20) is matched with the outer diameter of the outer ring of the elastic support bearing (70), the elastic support bearing (70) is axially positioned by the bearing positioning ring (40), the bearing outer ring pressure cover (60) and the bearing clamping nut (80), and the bearing end cover (30) is installed on the other side of the bearing seat (10).

7. A support structure according to claim 6, characterized in that: When the damping bolts (22) are completely screwed into the threaded through holes (21), the rigidity of the support structure is maximum.

8. A support structure according to claim 6, characterized in that: The damping bolts (22) are installed in a radial circumference in a number of 2n-1, and all the m axial ones are installed in the threaded through holes (21). The rigidity of the elastic squirrel cage support seat is isotropic.

9. A support structure according to claim 6, characterized in that: The damping bolts (22) are all installed in the radial circumference according to n numbers, and are installed in the threaded through holes (21) in the axial direction according to 2m-1 numbers. The rigidity of the elastic squirrel cage support seat is isotropic.

Images