Boss-spoke configuration elastic ring supporting damping structure and calculation method

Abstract

The present application belongs to the field of aero-engine supporting damping system, and discloses a boss-spoke configuration elastic ring supporting damping structure, which comprises an inner ring, an outer ring and a spoke structure; an annular gap is formed between the inner ring and the outer ring, and the spoke structure is fixedly arranged in the annular gap; the spoke structure is plate-shaped and is arranged eccentrically to the shaft center of the inner and outer ring walls, a plurality of spoke structures are arranged around the circumference of the inner and outer ring walls, the annular gap is divided into a plurality of sliding oil cavities, and the sliding oil cavities are filled with metal rubber or sliding oil; the low stiffness design requirement of the elastic ring in the aero-engine supporting system is effectively considered, the required design stiffness can be achieved by adjusting the characteristic parameters of the elastic ring, and the method of sliding oil extrusion or filling high-damping material (metal rubber) can be used to play a damping role when the elastic ring is deformed, so as to achieve the high-damping design requirement of the supporting structure.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine support vibration reduction systems, specifically relating to an elastic ring support damping structure with a boss-spoke configuration and a calculation method. Background Technology

[0002] Properly designed dampers at the support points of aero-engine rotors can effectively reduce vibration. Elastic ring-type squeeze film dampers can effectively improve the nonlinear characteristics of oil film stiffness while also possessing frequency modulation capabilities, and are widely used in various types of aero-engines. The elastic ring is used to support the high-speed rotor, and its engineering design requires the elastic ring to have low stiffness and high damping dynamic characteristics.

[0003] Fausto C proposed a novel spoke-type elastic ring in patent (US7553123 B2). This spoke-type elastic ring consists of a one-piece outer thin ring, circumferentially uniformly distributed thin-walled spokes, and circumferentially segmented inner thin sheets, with circumferential gaps between the inner thin sheets. During assembly, the outer bearing ring mates with the inner thin sheets, and the outer thin sheets mate with the inner wall of the bearing housing. Under radial force, the inclined spokes tilt further angularly, and the inner thin sheets deform radially outward, thus generating radial support stiffness. However, the elastic ring obtained by the above structure cannot well meet the design requirements for low stiffness of elastic rings.

[0004] Roy T.'s patent (US4044628) and Malcolm H.'s patent (US4872767) propose a labyrinthine elastic ring structure. The labyrinthine elastic ring can be designed as a multi-layered structure according to the required support stiffness, with each layer interconnected to form a whole. Under radial force, the elastic ring undergoes radial deformation to provide support stiffness. When the rotor system speed approaches the critical speed, the increased radial deformation of the elastic ring causes the arc segments of adjacent layers to radially adhere and press together, resulting in a sudden increase in radial stiffness. This alters the dynamic characteristics of the rotor system, allowing it to quickly pass the critical speed through this variable stiffness design. Furthermore, when each layer of the elastic ring deforms radially, the deformation and circumferential flow of the lubricating oil significantly improve the oil film stiffness and damping, thus achieving variable stiffness and damping vibration reduction. This elastic structure itself is relatively complex; introducing lubricating oil requires specially designed oil passages, which introduces additional mass and further increases the complexity of the structure. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the present invention provides an elastic ring support damping structure with a boss-spoke configuration, thereby solving the problems in the prior art. The technical solution adopted by the present invention is as follows:

[0006] An elastic ring support damping structure with a boss-spoke configuration includes: an inner ring, an outer ring, and a spoke structure;

[0007] An annular gap is formed between the inner ring and the outer ring, and the spoke structure is fixedly installed within the annular gap;

[0008] The spoke structure is plate-shaped and eccentrically positioned with respect to the inner and outer ring walls. Multiple spoke structures are arranged circumferentially around the inner and outer ring walls, dividing the annular gap into multiple lubricating chambers. The lubricating chambers are used to fill with metal rubber or lubricating oil.

[0009] Furthermore, the outer ring has multiple outer protrusions on its outer surface circumferentially, and the inner ring has multiple inner protrusions on its inner surface circumferentially.

[0010] Furthermore, in the circumferential direction of the inner and outer ring walls, the spoke-like structure, the inner boss, and the outer boss are distributed alternately.

[0011] Furthermore, the inner ring is provided with a damping hole, which is connected to the lubricating oil cavity for lubricating oil to enter. The spoke structure is provided with a through hole for lubricating oil to pass through, so that lubricating oil can enter the adjacent lubricating oil cavity.

[0012] A damping calculation method for a low-stiffness elastic ring with a boss-spoke combination configuration includes:

[0013] Establish a coordinate system with the center of the outer ring as the origin of the polar coordinate system. After precession, the center of the inner ring is (r0, θ0).

[0014] O′(r0,θ0)=f(t)

[0015] For the established polar coordinate system, the trajectory of the inner circle's center is:

[0016] R' 2 +r0 2 -2R'r0cos(θ-θ0)=r 2

[0017] After deformation, the clearance size of the lubricating oil cavity at each circumferential position is:

[0018] h(θ)=F(r0,θ0,△x)

[0019] Where Δx represents the magnitude of the deformation of the spokes. When the spokes are short, h(θ) can be obtained using the beam section assumption;

[0020] The area of ​​each cross-section is:

[0021]

[0022] The axial length of the elastic ring is L, and its volume change is:

[0023] V i =lS i -V / n

[0024] Where V is the total volume of the lubricating oil cavity;

[0025] Let the lubricating oil chamber with the largest compression be numbered 1, then the lubricating oil chamber with the largest compression is numbered k, and the volume change has the following relationship:

[0026]

[0027]

[0028] The inflow rate q of each lubricating oil chamber i+1 and outflow q i for:

[0029] q2=kq1-V2

[0030] q i =q i-1 -V i

[0031] Finally, based on the inflow and outflow rates of each lubricating oil cavity, the magnitude of the flow damping is calculated according to conventional throttling losses.

[0032] The present invention has the following beneficial effects:

[0033] 1. This invention effectively considers the low stiffness design requirements of the elastic ring in the aero-engine support system. By designing a series of boss-spoke-boob structures, the required low stiffness design is achieved (simulation calculations show a stiffness on the order of 10⁵ to 10⁶ N / m). Its stiffness and elastic ring characteristics are closely related to the number and thickness of the bosses and spokes, and the required design stiffness can be achieved by adjusting the characteristic parameters of the elastic ring.

[0034] 2. The present invention can use the method of extruding or filling with high damping material (metal rubber) to fill the cavity between the boss-spoke type elastic ring with oil film or damping material, so as to play a role in damping and vibration reduction when the elastic ring deforms, so as to achieve the high damping design requirements of the support structure. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of a boss-spoke type elastic ring structure;

[0036] Figure 2 This is a schematic diagram of the deformation of a boss-spoke type elastic ring;

[0037] Figure 3 This is a schematic diagram of the flow of lubricating oil in a boss-spoke type elastic ring;

[0038] Figure 4 This is a schematic diagram of the local lubricating oil flow in a boss-spoke type elastic ring;

[0039] Figure 5 This is a schematic diagram of a boss-spoke type elastic ring filled with metal rubber;

[0040] Figure 6 Changes in the volume of each cavity of the elastic ring after deformation. Detailed Implementation

[0041] The following will be based on embodiments of the present invention. Figures 1-5 The technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0042] like Figure 1 An elastic ring support damping structure with a boss-spoke configuration includes: an inner ring 4, an outer ring 3, and a spoke structure 5;

[0043] An annular gap is formed between the inner ring 4 and the outer ring 3, and the spoke structure 5 is fixedly installed in the annular gap;

[0044] The spoke structure 5 is plate-shaped and eccentrically positioned with respect to the inner and outer ring walls. Multiple spoke structures 5 are arranged circumferentially around the inner and outer ring walls, dividing the annular gap into multiple lubricating chambers. The lubricating chambers are used to fill with metal rubber or lubricating oil.

[0045] Furthermore, the outer ring 3 has a plurality of outer protrusions 2 arranged circumferentially on its outer surface, and the inner ring 4 has a plurality of inner protrusions 1 arranged circumferentially on its inner surface.

[0046] Furthermore, in the circumferential direction of the inner and outer ring walls, the spoke structure 5, the inner boss 1, and the outer boss 2 are staggered.

[0047] Furthermore, the inner ring 4 is provided with a damping hole 8, which is connected to the lubricating oil cavity for lubricating oil to enter. The spoke structure 5 is provided with a through hole for lubricating oil to pass through, so that lubricating oil can enter the adjacent lubricating oil cavity.

[0048] Specifically, the inner ring 4, outer ring 3, and spoke-shaped structure 5 together constitute the structure of the elastic ring. The outer boss 2, inner boss 1, and spoke-shaped structure 5 are evenly distributed around the circumference of the elastic ring, repeating in a specific order along the circumference, with each pair of them having the same angle. The spoke-shaped structure 5 is an inclined plate-like structure, and its distribution direction can be along the tangent of the inner ring 4. The elastic ring is made of spring steel to achieve the required low stiffness design.

[0049] There are two ways to achieve the damping effect of the elastic ring. One is by filling it with metal rubber, which is made by winding and cold-pressing metal wires. The relevant characteristic parameters of the metal rubber are calculated based on the required damping. The other method is to provide damping through oil supply. The oil supply scheme can be designed based on experimentally obtained rules to meet the damping design requirements of the aero-engine support system. The specific calculation method is as follows:

[0050] The flow of lubricating oil in each lubricating cavity within the spoke structure can be calculated using the following method:

[0051] The deformation of the elastic ring affects the volume change of each lubricating cavity in the elastic ring, and the main changes are as follows: Figure 2 As shown:

[0052] Assuming that each spoke structure 5 has a relatively small influence, and the span of the spoke structure 5 (the span being the central angle corresponding to the spoke) is α; let the number of spoke structures 5 be n, then the span occupied by each lubricating cavity is Ω = 2π / n, and α < Ω; both the inner and outer ring surfaces of the elastic ring have a large contact area with the contact surface, and the fit is an interference fit, therefore both can be considered as rigid rings. Establish a coordinate system with the center of the outer ring 3 as the origin of the polar coordinate system, and after precession, the center of the inner ring 4 is O′(r0,θ0). The two coordinates show the motion trajectory of the inner ring 4, both being functions of time. h(θ) is the oil film clearance, which, for ease of calculation and expression, is defined as the clearance between the inner ring 4 and the spoke structure 5 or the outer ring 3.

[0053] The positions of the four inner ring centers as time changes are as follows:

[0054] O′(r0,θ0)=f(t)

[0055] Establish a polar coordinate system with O as the center. For the established polar coordinate system, the trajectory of the four inner ring centers is as follows:

[0056] R' 2 +r0 2 -2R'r0cos(θ-θ0)=r 2

[0057] After deformation, the clearance size of the lubricating oil cavity at each circumferential position is:

[0058] h(θ)=F(r0,θ0,△x)

[0059] Where Δx represents the deformation of the spoke structure 5. When the spokes are relatively short, h(θ) can be obtained using the beam section assumption;

[0060] Two radial sections are drawn in the lubricating oil cavity. The area of ​​each section is as follows:

[0061]

[0062] The lubricating oil cavity can be divided into three parts: the lubricating oil cavity above the spokes, the lubricating oil cavity below the spokes, and the lubricating oil cavity between the two spokes. The sum of the cross-sections of these three parts equals the aforementioned cross-sectional size. Furthermore, the sizes of each cross-sectional area can be derived:

[0063]

[0064] The axial length of the elastic ring is L, and its volume change is:

[0065] V i =lS i -V / n

[0066] Where V is the total volume of the lubricating oil chambers. It can be seen that some lubricating oil chambers increase in volume, while others decrease. The lubricating oil flows between the annular gaps. However, the increase or decrease in volume of each lubricating oil chamber does not correspond to the amount of lubricating oil flowing in and out of each chamber. Except for the lubricating oil chambers with the largest decrease in volume and the largest increase in volume, all other lubricating oil chambers have both inflow and outflow of lubricating oil. Let the lubricating oil chamber with the largest compression be numbered 1, then the lubricating oil chamber with the largest compression is numbered k (n / 2 for even-numbered lubricating oil chambers, (n+1) / 2 for odd-numbered lubricating oil chambers), and the volume change has the following relationship:

[0067] V1=q1

[0068] kq1-q2=V2

[0069] q2-q3=V3 ......

[0071] q k-1 =V k

[0072] q is the flow rate out of the lubricating oil cavity, while V is a scalar quantity, but it is not positive or negative; a positive number indicates an increase in volume.

[0073] further:

[0074]

[0075]

[0076] This leads to the deduction of the inflow rate q in each lubricating oil chamber. i+1 and outflow q i .that is:

[0077] q2=kq1-V2

[0078] q i =q i-1 -V i

[0079] The flow rate in and out of each lubricating oil cavity is obtained by the above method, and then the flow velocity of lubricating oil through the small hole is obtained.

[0080] v i =q i / (πd 2 / 4)

[0081] d is the diameter of the small hole, v i The flow rate of lubricating oil through the small hole.

[0082] The lubricating oil flow resistance loss in the lubricating oil cavity can be calculated using the Darcy-Weisbach formula:

[0083]

[0084] f is the friction factor, l is the orifice length, and the lubricating oil flow resistance loss can be used as a parameter to evaluate the damping magnitude of lubricating oil flow in the lubricating oil cavity. The actual damping magnitude needs to be obtained by simulating or testing the support load and then analyzing the support response.

[0085] The working principle of this invention is as follows:

[0086] An elastic ring is installed between the outer bearing ring 7 and the bearing housing of the aero-engine rotor. When the rotor rotates at high speed, a dynamic load is generated at the support structure. Under this load, the bearing compresses the elastic ring, causing it to deform. The stiffness of the elastic ring can be adjusted according to design requirements, thereby controlling its deformation. Simultaneously, based on simulation and experimental data, the damping effect of this boss-spoke type elastic ring can be evaluated and verified, revealing the variation of damping with the characteristic parameters of the elastic ring. Ultimately, an elastic ring that meets engineering design requirements can be optimized and designed.

[0087] The height of the inner boss on the elastic ring determines the size of the space formed between the boss and the ring wall, and between the spoke structure 5 and the ring wall, for filling the damping material. This has a significant impact on the damping characteristics of the elastic ring and can be used as a key characteristic parameter for the damping design of the elastic ring.

[0088] The damping holes 8 on the elastic ring are distributed between the outer ring 3 and the inner ring 4. Specifically, there are two rows of damping holes 8 in the axial direction, and the damping holes 8 are evenly distributed between the spoke structure 5 and the outer boss 1 and between the spoke structure 5 and the inner boss 2. At the same time, holes are opened on each spoke structure to accelerate the flow between each lubricating oil cavity.

[0089] The openings in the ring walls between the bosses of the elastic ring allow lubricating oil to flow between the cavity formed between the inner bosses 2, the cavity formed between the spoke structure 5 and the inner and outer ring walls, and the cavity formed between the outer bosses 1, providing damping for the elastic ring. Lubricating oil enters the annular cavity between the elastic ring and the bearing housing from the oil supply hole, then enters the cavity formed between the two ring walls and the spoke structure 5 through the damping hole 8 on the outer ring 3, and finally enters the cavity formed between the outer bearing ring 7 and the elastic ring through the damping hole 8 on the inner ring 4, ultimately filling the entire cavity. For a metal-rubber filling scheme, the designed metal-rubber can be filled into the corresponding cavities before installation.

[0090] Under dynamic loads at the fulcrum, the elastic ring deforms. The boss-spoke type elastic ring designed in this invention has low stiffness, making it more prone to deformation under dynamic loads at the fulcrum, resulting in greater volume changes in each cavity. A larger rate of cavity volume change indicates a greater compressive effect on the lubricating oil or metal-rubber filling the cavities, leading to better overall damping.

[0091] After the elastic ring deforms, it dampens the lubricating oil or metal rubber within it under compression, thereby reducing vibration in the rotor system. The elastic ring involved in this invention has low stiffness, and its structural features are easily adjustable, allowing it to adapt well to the design conditions of different aero-engine support structures. The larger deformation of the elastic ring provides greater compression space for the lubricating oil or metal rubber, resulting in better damping effect from the rotor support structure.

[0092] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any modifications, alterations, alterations, or substitutions made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for calculating the lubricating oil flow damping of a low-stiffness elastic ring, characterized in that, include: Inner ring (4), outer ring (3) and spoke structure (5); An annular gap is formed between the inner ring (4) and the outer ring (3), and the spoke structure (5) is fixedly installed in the annular gap; The spoke structure (5) is plate-shaped and eccentrically arranged with respect to the axis of the inner and outer ring walls. Multiple spoke structures (5) are arranged around the inner and outer ring walls in the circumferential direction, dividing the annular gap into multiple lubricating chambers. The lubricating chambers are used to fill metal rubber or lubricating oil. Establish a coordinate system with the center of the outer ring (3) as the origin of the polar coordinate system, and the center of the inner ring (4) after precession is... ; For the established polar coordinate system, the trajectory of the center of the inner ring (4) is: After deformation, the clearance size of the lubricating oil cavity at each circumferential position is: in The magnitude of the deformation of the spoke structure (5); when the spoke structure (5) is a short spoke, it is obtained using the section beam assumption. ; The area of ​​each cross-section is as follows: The axial length of the elastic ring is L, and its volume change is: in V This refers to the total volume of the lubricating oil cavity; Let the number of the lubricating oil chamber be k, and the number of the lubricating oil chamber with the largest compression be 1. ， The volume change has the following relationship: Inflow rate of each lubricating oil chamber q i+1 and outflow q i for: Finally, based on the inflow and outflow rates of each lubricating oil cavity, the magnitude of the flow damping is calculated according to conventional throttling losses.

2. A boss-spoke configuration of an elastic ring support damping structure, characterized in that, include: Inner ring (4), outer ring (3) and spoke structure (5); An annular gap is formed between the inner ring (4) and the outer ring (3), and the spoke structure (5) is fixedly installed in the annular gap; The spoke structure (5) is plate-shaped and eccentrically arranged with respect to the inner and outer ring walls. Multiple spoke structures (5) are arranged around the inner and outer ring walls in a circumferential direction, dividing the annular gap into multiple lubricating cavities. The lubricating cavities are used to fill metal rubber or lubricating oil.

3. The elastic ring support damping structure with a boss-spoke configuration according to claim 2, characterized in that, The outer ring (3) has multiple outer protrusions (2) arranged circumferentially on its outer surface, and the inner ring (4) has multiple inner protrusions (1) arranged circumferentially on its inner surface.

4. The elastic ring support damping structure with a boss-spoke configuration according to claim 3, characterized in that, In the circumferential direction of the inner and outer ring walls, the spoke structure (5), the inner boss (1) and the outer boss (2) are staggered.

5. The elastic ring support damping structure with a boss-spoke configuration according to claim 2, characterized in that, Both the inner ring (4) and the outer ring (3) are provided with damping holes (8), which are connected to the lubricating oil cavity for lubricating oil to enter. The spoke structure (5) is provided with a through hole for lubricating oil to pass through, so that lubricating oil can enter the adjacent lubricating oil cavity.

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