A squirrel cage elastic support structure with pre-adjusted concentric design

Abstract

The present application belongs to the field of engine test technology, and specifically relates to a squirrel cage elastic support structure with a pre-adjusted concentric design. The device comprises: an annular main body (1), the inner wall of the annular main body (1) is rotatably connected to a power turbine rotor (100), and the outer wall of the annular main body (1) is sleeved on the inside of the cylinder of the elastic support mounting seat (200) through an elastic support limiting gap; a plurality of support arms (2) are evenly arranged in the circumferential direction of the annular main body (1), and the end of each support arm (2) is fixedly connected to the front end stop of the cylinder of the elastic support mounting seat (200) through a mounting edge (21); the annular main body (1) is an eccentric structure in which the thickness of the lower end of the main body is greater than the thickness of the upper end of the main body, and the eccentricity is not higher than the theoretical eccentricity calculated by the ratio of the support load to the elastic support stiffness. The present application effectively solves the damping failure problem that may occur during the elastic support operation, and can provide a better vibration reduction effect for the system.

Description

Technical Field

[0001] The present application belongs to the field of engine testing technology, and specifically relates to a squirrel cage elastic support structure with a pre-adjusted concentric design. Background Art

[0002] Vibration in aircraft engines and aero-derivative gas turbines directly impacts their lifespan and safety. Statistics show that over 90% of structural failures are caused by or related to vibration. Aircraft and gas turbines are complex structures and operate in harsh conditions, and numerous factors can influence overall vibration. Using a spring-loaded damper is the most effective way to reduce engine vibration and improve stability. A spring-loaded damper uses an elastic structure to support the rotor shaft. This structure also creates oil film holes between the structure and the engine casing, allowing oil injection to provide vibration damping.

[0003] During the development and use of aircraft engines (including aero-derivative gas engines), vibration failures of the entire engine due to structural characteristics are a key factor affecting safety and reliability. In addition to ensuring that the rotor-support system has good vibration characteristics, the use of elastic supports or elastic damper structures (to provide vibration suppression effects) at the fulcrum position is the most direct and effective means to reduce the vibration level of the entire engine and improve safety and reliability. To ensure the vibration reduction effect of the elastic support structure, the limit gap or damper oil film thickness needs to be as uniform as possible in the circumferential direction, that is, the inner and outer rings of the elastic support limit surface should be as concentric as possible. Therefore, the design process must consider pre-adjustment of concentricity.

[0004] The existing squirrel cage elastic support design is mainly based on three parameters: stiffness, fatigue and damping effect. The problem is that the design process lacks pre-adjustment concentricity judgment and related structural adaptability design. As a result, when the support load is large and the elastic support stiffness is small, the limit gap / damper oil film thickness cannot be guaranteed to be uniform in the circumferential direction, resulting in poor vibration reduction effect or even failure. Summary of the Invention

[0005] In order to solve one of the above problems, the present application provides a squirrel cage elastic support structure with a pre-adjusted concentric design, which mainly includes:

[0006] An annular body having an inner wall and an outer wall, the inner wall of the annular body being rotatably connected to the power turbine rotor, and the outer wall of the annular body being sleeved within the cylindrical body of the elastic support mounting seat via an elastic support limiting gap, wherein oil can be injected into the elastic support limiting gap to form a damper oil film between the squirrel cage elastic support structure and the elastic support mounting seat;

[0007] A plurality of support arms are evenly arranged in the circumferential direction of the annular body, each arm extending along a first direction and forming a mounting edge at the end, each mounting edge being fixedly connected to the front end stop of the cylinder of the elastic support mounting seat, wherein the first direction is parallel to the central axis of the annular body;

[0008] The annular body is an eccentric structure in which the thickness of the lower end of the body is greater than the thickness of the upper end of the body. The lower end of the body refers to the part located at the lower end in the vertical direction when the annular body is installed between the power turbine rotor and the elastic support mounting seat. Correspondingly, the upper end of the body refers to the part located at the upper end in the vertical direction when the annular body is installed between the power turbine rotor and the elastic support mounting seat. The eccentricity is not higher than the theoretical eccentricity calculated by the ratio of the support load to the elastic support stiffness.

[0009] Preferably, the annular body is connected to the power turbine rotor via a rotor support bearing.

[0010] Preferably, the rotor support bearing has a mounting end fixedly connected to its bearing outer ring, the inner wall of the annular body has a front end face and a rear end face, the front end face is fixed to the mounting end by a plurality of first bolts arranged along the circumferential direction, and the rear end face is pressed onto the rear end of the bearing outer ring through a stop.

[0011] Preferably, the mounting edge of each support arm is fixed to the front end stop of the cylinder of the elastic support mounting seat by a second bolt.

[0012] Preferably, the front end stop of the cylinder of the elastic support mounting seat has a flange extending outward in the radial direction of the cylinder, and the mounting edge of the support arm is a plate structure parallel to the flange, which is crimped and fixed on the flange.

[0013] Through the structural pre-adjusted concentric design, this application obtains a squirrel cage spring support structure that can still ensure the limit gap or oil film uniformity in a large support load environment, effectively solves the damping failure problem that may occur during the spring support operation, and can provide better vibration reduction effect for the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a structural schematic diagram of a preferred embodiment of a squirrel cage elastic support structure using a pre-adjusted concentric design in this application.

[0015] Figure 2 For this application Figure 1 Schematic diagram of the installation of the squirrel cage elastic support structure of the embodiment shown.

[0016] Figure 3 For this application Figure 1 Schematic diagram of the T-direction structure of the embodiment shown.

[0017] Among them, 1-annular body, 2-support arm, 21-mounting edge, 3-damper oil film;

[0018] 100-power turbine rotor, 101-rotor support bearing, 102-bearing outer ring, 103-mounting end, 200-elastic support mounting seat, 201-flanged edge, 300-first bolt, 400-second bolt. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the implementation of this application clearer, the technical solutions in the implementation of this application will be described in more detail below in conjunction with the drawings in the implementation of this application. In the drawings, the same or similar numbers throughout represent the same or similar elements or elements with the same or similar functions. The described implementation is a part of the implementation of this application, not all of the implementations. The implementation described below with reference to the drawings is exemplary and is intended to be used to explain this application, and should not be understood as a limitation on this application. Based on the implementation in this application, all other implementations obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The implementation of this application is described in detail below in conjunction with the drawings.

[0020] The present application provides a squirrel cage elastic support structure with a pre-adjusted concentric design, such as Figure 1-Figure 3 As shown, it mainly includes:

[0021] An annular body 1 having an inner wall and an outer wall. The inner wall of the annular body 1 is rotatably connected to the power turbine rotor 100. The outer wall of the annular body 1 is sleeved within the cylindrical body of the elastic support mounting seat 200 via an elastic support limiting gap. Oil can be injected into the elastic support limiting gap to form a damper oil film 3 between the squirrel cage elastic support structure and the elastic support mounting seat.

[0022] Multiple support arms 2 are evenly arranged around the annular body 1. Each support arm 2 extends along a first direction and forms a mounting edge 21 at the end. Each mounting edge 21 is fixedly connected to the front end stop of the cylinder of the elastic support mounting seat 200. The first direction is parallel to the central axis of the annular body 1.

[0023] The annular body 1 is an eccentric structure in which the thickness of the lower end of the body is greater than the thickness of the upper end of the body. The lower end of the body refers to the part located at the lower end in the vertical direction when the annular body 1 is installed between the power turbine rotor 100 and the elastic support mounting seat 200. Correspondingly, the upper end of the body refers to the part located at the upper end in the vertical direction when the annular body 1 is installed between the power turbine rotor 100 and the elastic support mounting seat 200. The eccentricity is not higher than the theoretical eccentricity calculated by the ratio of the support load to the elastic support stiffness.

[0024] This application uses a through-hole in the spring-loaded support mounting base 200 to inject oil into the spring-loaded support gap. This allows for research into the effects of the damper's oil supply and discharge pressures on vibration damping. This can be achieved by adjusting the oil supply and discharge pressures in the oil supply system, and vibration measurements can reveal the influence of vibration suppression. Furthermore, injecting oil into the spring-loaded support gap through the through-hole also allows for research into the effects of lubricant viscosity, which can be achieved by adjusting the oil temperature or replacing the lubricant.

[0025] refer to Figure 3 In this application, the annular body 1 of the squirrel cage elastic support structure is set to an eccentric structure. Specifically, the annular body of the squirrel cage elastic support structure at the lower end is set to be thicker, that is, the distance from the inner wall to the outer wall of the annular body 1 is larger, thereby offsetting the problem of uneven thickness of the damper oil film 3 in the circumferential direction caused by the deadweight of the squirrel cage elastic support structure. The pre-adjusted concentricity is set at the stop position where the squirrel cage elastic support structure is connected to the elastic support mounting seat 200. The design is that the stop at which the squirrel cage elastic support structure is connected to the elastic support mounting seat 200 is vertically eccentric. The theoretical eccentricity = fulcrum load / elastic support stiffness. The actual processing eccentricity must also take into account the influence of processing accuracy. Generally, the actual processing eccentricity is less than the theoretical eccentricity. For example, when the elastic support stiffness is 2.56×10 7 N / m, the radial load under deadweight state is 2188N, and the theoretical eccentricity calculated from this is 0.085mm. Taking into account the machining accuracy of the eccentric surface, it is finally determined that the actual machining eccentricity can be set to 0.07mm.

[0026] Because the connection between the squirrel cage elastic support structure and the elastic support mounting seat has an eccentric structure based on pre-adjusted concentricity, assembly marks must be set to prevent assembly errors in the eccentric direction; after the pre-adjusted concentricity design, a fatigue reserve analysis should also be carried out on the elastic support structure, thereby ensuring the stiffness requirements of the squirrel cage elastic support structure, the damping requirements of the damper and the uniformity of the oil film.

[0027] In some optional embodiments, the annular body 1 is connected to the power turbine rotor 100 via a rotor support bearing 101, thereby reducing the rotational resistance between the squirrel cage elastic support structure and the power turbine rotor.

[0028] In some optional embodiments, the rotor support bearing 101 has a mounting end 103 fixedly connected to its bearing outer ring 102, and the inner wall of the annular body 1 has a front end face and a rear end face, the front end face is fixed to the mounting end 103 by a plurality of first bolts 300 arranged along the circumferential direction, and the rear end face is crimped to the rear end of the bearing outer ring 102 by a stop.

[0029] refer to Figure 2The squirrel cage elastic support structure and the rotor support bearing 101 are fastened together by the first bolt 300. On the other hand, the rotor support bearing 101 is prevented from moving in the axial direction by means of stop crimping. In an alternative embodiment, the mounting end 103 may be a part of the rotor support bearing 101 or another structure rotatably connected to the power turbine rotor 100.

[0030] In some optional embodiments, the mounting edge 21 of each support arm 2 is fixed to the front end stop of the cylinder of the elastic support mounting seat 200 by a second bolt 400 .

[0031] In some optional embodiments, the front end stop of the cylinder of the elastic support mounting seat 200 has a flange 201 extending outward in the radial direction of the cylinder, and the mounting edge 21 of the support arm 2 is a plate structure parallel to the flange 201, which is crimped and fixed on the flange 201.

[0032] Although the present application has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications or improvements may be made based on the present application. Therefore, such modifications or improvements, which do not depart from the spirit of the present application, are within the scope of protection claimed in the present application.

Claims

1. A squirrel cage elastic support structure with a pre-adjusted concentric design, characterized in that: include: An annular body (1), the annular body (1) having an inner wall and an outer wall, the inner wall of the annular body (1) being rotatably connected to a power turbine rotor (100), the outer wall of the annular body (1) being sleeved inside a cylindrical body of an elastic support mounting seat (200) via an elastic support limiting gap, oil being injectable into the elastic support limiting gap to form a damper oil film (3) between the squirrel cage elastic support structure and the elastic support mounting seat; A plurality of support arms (2) are evenly arranged in the circumferential direction of the annular body (1), each support arm (2) extends along a first direction and forms a mounting edge (21) at the end, each mounting edge (21) is fixedly connected to the front end stop of the cylinder of the elastic support mounting seat (200), wherein the first direction is parallel to the central axis of the annular body (1); The annular body (1) is an eccentric structure in which the thickness of the lower end of the body is greater than the thickness of the upper end of the body. The lower end of the body refers to the portion located at the lower end in the vertical direction when the annular body (1) is installed between the power turbine rotor (100) and the elastic support mounting seat (200). Correspondingly, the upper end of the body refers to the portion located at the upper end in the vertical direction when the annular body (1) is installed between the power turbine rotor (100) and the elastic support mounting seat (200). The eccentricity is not higher than the theoretical eccentricity calculated by the ratio of the support load to the elastic support stiffness.

2. The squirrel cage elastic support structure with pre-adjusted concentric design according to claim 1, characterized in that: The annular body (1) is connected to the power turbine rotor (100) via a rotor support bearing (101).

3. The squirrel cage elastic support structure with pre-adjusted concentric design according to claim 2, characterized in that: The rotor support bearing (101) has a mounting end (103) fixedly connected to its bearing outer ring (102); the inner wall of the annular body (1) has a front end face and a rear end face; the front end face is fixed to the mounting end (103) by a plurality of first bolts (300) arranged along the circumferential direction; and the rear end face is press-fitted to the rear end of the bearing outer ring (102) by a stopper.

4. The squirrel cage elastic support structure with pre-adjusted concentric design according to claim 1, characterized in that: The mounting edge (21) of each support arm (2) is fixed to the front end stop of the cylinder of the elastic support mounting seat (200) via a second bolt (400).

5. The squirrel cage elastic support structure with pre-adjusted concentric design according to claim 4, characterized in that: The front end stop of the cylinder of the elastic support mounting seat (200) is provided with a flange (201) extending outwardly in the radial direction of the cylinder, and the mounting edge (21) of the support arm (2) is a plate structure parallel to the flange (201), which is crimped and fixed on the flange (201).

Images