A multi-stage vibration-reducing squeeze film damper that inhibits vapor cavitation

Abstract

The application relates to a multi-stage vibration reduction extrusion oil film damper for inhibiting steam cavitation, which comprises a bearing, a squirrel-cage elastic support and a metal bushing arranged in sequence from an inner ring to an outer ring, oil supply holes are formed in the metal bushing, an annular elastic body oil storage cavity is fixed to the outer ring of the squirrel-cage elastic support, the elastic body oil storage cavity is hollow and forms a second layer of oil film, a first layer of oil film is formed between the inner ring of the squirrel-cage elastic support and the bearing, a third layer of oil film is formed between the outer ring of the elastic body oil storage cavity and the metal bushing, the first layer of oil film and the second layer of oil film are communicated, the second layer of oil film and the third layer of oil film are communicated, an oil sealing end cover is fixed to the end of the metal bushing and is attached to the end surface of the bearing, an inner oil groove communicated with the first layer of oil film and an outer oil groove communicated with the third layer of oil film are formed in the inner side of the oil sealing end cover, and a communication oil channel communicated with the inner oil groove and the outer oil groove is formed in the inner side of the oil sealing end cover, vibration response is gradually reduced, the vibration reduction capacity is stronger, and the purpose of inhibiting steam cavitation is achieved.

Description

Technical Field

[0001] This invention relates to the field of extrusion oil film damper technology, specifically to a multi-stage vibration damping extrusion oil film damper for suppressing vapor cavitation. Background Technology

[0002] In high-speed rotating rotor systems, due to installation errors and gravity, the rotor's center of mass may not coincide with its axis of rotation, resulting in an unbalanced force during rotation. This imbalance causes the rotor to exhibit periodic vibrations during rotation, easily leading to significant vibrations. Furthermore, rotors often operate at or above the first or multiple critical speeds; as they approach or pass these critical speeds, the vibration response increases significantly. If these vibrations are not controlled, they can lead to equipment malfunctions or even serious damage.

[0003] Squeeze film dampers (SFDs) are a commonly used type of support damping structure in rotating machinery. The space between the rotor and the support is filled with lubricating oil. When the rotor vibrates, the oil film in the SFD is squeezed due to the viscosity of the lubricating oil, generating a damping force. This reduces the vibration energy and amplitude of the system, thereby improving the dynamic characteristics of the rotor system. When the rotor passes its critical speed, it can effectively reduce the transmitted vibration at the rotor support, improving the stability of the rotor system. For high-performance rotating machinery such as aero-engines, extensive engineering practice has shown that the application of SFDs can effectively suppress rotor vibration magnitude, improving the performance, lifespan, structural integrity, and reliability of the machinery.

[0004] The existing squeeze film damper has the following disadvantages:

[0005] (1) Vapor cavitation: During rotor rotation, the oil film area compressed by the journal forms a positive pressure zone, while the oil film area away from the journal forms a negative pressure zone. When the lubricating oil in the negative pressure zone is lower than the saturated vapor pressure, the lubricating oil vaporizes to form steam, generating vapor cavitation. Vapor cavitation can cause oil film rupture, damaging the integrity of the oil film and preventing the damper from working effectively; furthermore, the generation and disappearance of vapor cavitation can impact the damper, thus shortening the service life of the equipment. Currently, both open-type and end-sealed extrusion oil film dampers inevitably generate vapor cavitation.

[0006] (2) Air intake: When the pressure in the negative pressure zone of the squeeze film damper is lower than the atmospheric pressure, air will be drawn into the lubricating oil, forming a large number of air bubbles in the lubricating oil and hindering the flow of the lubricating oil. When a large amount of air is drawn into the squeeze film damper, the lubricating oil cannot circulate fully, which increases the friction of the lubricating oil and causes local overheating of the lubricating oil, thereby reducing the damping capacity of the damper.

[0007] (3) Regarding oil film stability: oil film thickness is an important parameter affecting the damping effect of the damper. For aero engines with high damping requirements, the damping capacity of a single oil film cannot meet the requirements. In order to enhance the damping capacity of a single oil film, the thickness of the oil film is usually reduced. However, if the oil film thickness is too small, although it will bring greater damping, the oil film will be squeezed more severely during the journal precession process, causing nonlinear changes in oil film stiffness, which may lead to damping failure of the damper in severe cases. Summary of the Invention

[0008] This invention addresses the shortcomings of existing technologies by providing a multi-stage vibration damping extrusion oil film damper for suppressing vapor cavitation. This damper is applied to the rotor-support structure system of an aero-engine to solve the vapor cavitation problem in extrusion oil film dampers.

[0009] This invention is achieved through the following technical solution: a multi-stage vibration damping and compression oil film damper for suppressing vapor cavitation is provided, comprising a bearing, a squirrel cage elastic support, and a metal bushing arranged sequentially from the inner ring to the outer ring. The metal bushing has an oil supply hole. An annular elastic body oil reservoir is fixed to the outer ring of the squirrel cage elastic support. The elastic body oil reservoir is hollow and forms a second oil film. A first oil film is formed between the inner ring of the squirrel cage elastic support and the bearing. A third oil film is formed between the outer ring of the elastic body oil reservoir and the metal bushing. The first and second oil films are connected through an inner connecting hole assembly formed on the inner side of the squirrel cage elastic support and the inner ring of the elastic body oil reservoir. The second and third oil films are connected through an outer connecting hole assembly formed on the outer side of the outer ring of the elastic body oil reservoir.

[0010] As an optimization, the outer connecting hole assembly includes two rows of outer ring oil seepage holes disposed on the outer ring of the elastomer oil storage cavity, with multiple outer ring oil seepage holes disposed in each row along the circumference.

[0011] As an optimization, the inner connecting hole assembly includes two rows of inner ring oil seepage holes arranged in the inner ring of the oil storage cavity of the elastomer. Each row of inner ring oil seepage holes has multiple holes arranged circumferentially. The squirrel cage elastic support has two rows of elastic support oil seepage holes, each row of elastic support oil seepage holes has multiple holes arranged circumferentially and corresponds to the inner ring oil seepage holes.

[0012] As an optimization, each row of outer ring oil seepage holes has 8 holes arranged circumferentially, and each row of inner ring oil seepage holes has 16 holes arranged circumferentially. The diameter of the outer ring oil seepage holes is larger than the diameter of the inner ring oil seepage holes.

[0013] As an optimization, the end of the metal bushing is fixedly connected to an oil sealing end cap that fits against the bearing end face. The inner side of the oil sealing end cap has an inner oil groove that communicates with the first oil film and an outer oil groove that communicates with the third oil film. The inner side of the oil sealing end cap has a connecting oil passage that connects the inner oil groove and the outer oil groove.

[0014] As an optimization, the connecting oil passages are provided in at least two forms and are evenly distributed along the circumference.

[0015] As an optimization, the inner ring of the oil storage cavity of the elastomer is fixed with multiple trapezoidal tenons, and the outer ring of the elastic support of the squirrel cage is provided with trapezoidal mortises that are adapted to the trapezoidal tenons. The trapezoidal tenons are inserted into the trapezoidal mortises from the outer end of the elastic support of the squirrel cage.

[0016] As an optimization, the cross-sectional area of ​​the trapezoidal tenon gradually decreases from the outer end of the elastic support of the rat cage inward, and the outer end of the oil storage cavity of the elastic body fits against the inner side of the oil sealing end cap.

[0017] As an optimization, the inner side of the oil sealing end cap is positioned by a ring-shaped stepped end face and a metal bushing.

[0018] As an optimization, the inner length of the elastomer oil reservoir is greater than the length of the squirrel cage elastic support.

[0019] The beneficial effects of this invention are as follows:

[0020] (1) Traditional extrusion oil film dampers only have a single layer of oil film. For aero engines with high vibration reduction requirements, the single-layer extrusion oil film damper cannot meet the requirements. At the same time, the thickness of the single layer of oil film is too small, which will cause nonlinearity of oil film stiffness when the extrusion degree is large, and in severe cases, the damper will fail to reduce vibration.

[0021] The multi-stage vibration damping extrusion oil film damper designed in this invention has three oil film regions. By reasonably controlling the thickness of each oil film, it solves the problems that a single oil film cannot meet the vibration damping requirements, and that the oil film thickness is too small and the oil film stiffness is severely nonlinear. This makes the vibration response decrease step by step and the vibration damping capacity stronger.

[0022] (2) Traditional extrusion oil film dampers have a two-phase flow phenomenon of vapor cavitation. Vapor cavitation can cause oil film rupture, destroy the integrity of the oil film, and prevent the damper from working effectively. Furthermore, the generation and disappearance of vapor cavitation will impact the damper, thereby shortening the service life of the equipment.

[0023] The elastomer oil storage cavity designed in this invention can not only act as a second layer of oil film to absorb vibration energy, but also adjust the pressure of the first layer of oil film according to the pressure difference, thereby suppressing vapor cavitation, ensuring the integrity of the oil film structure, improving oil film stability, and extending the service life of the equipment.

[0024] (3) Traditional open-type extrusion oil film dampers have a serious air intake phenomenon. When air is drawn into the lubricating oil, a large number of bubbles will form, which will hinder the flow of the lubricating oil, prevent the lubricating oil from circulating fully, increase the friction of the lubricating oil, and cause the lubricating oil to overheat locally, thereby reducing the damping capacity of the damper.

[0025] The oil sealing end cap designed in this invention can seal the first and third oil films, allowing lubricating oil to flow out from only one side, reducing air intake, increasing the effective working area of ​​the oil film, and improving the damping capacity of the damper. Attached Figure Description

[0026] Figure 1 This is a cross-sectional structural diagram of the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of the elastomer oil storage cavity of the present invention;

[0028] Figure 3 This is a front view of the elastomer oil reservoir of the present invention;

[0029] Figure 4 This is a schematic diagram of the inner side of the oil-sealing end cap of the present invention;

[0030] Figure 5 For the present invention Figure 4 A cross-sectional view of the AA plane;

[0031] Figure 6 This is a schematic diagram of the elastic support structure of the rat cage of the present invention;

[0032] As shown in the figure:

[0033] 1. First oil film, 2. Second oil film, 3. Third oil film, 4. Elastomer oil reservoir, 41. Outer ring oil seepage hole, 42. Inner ring oil seepage hole, 43. Trapezoidal tenon, 5. Oil sealing end cap, 51. Outer oil groove, 52. Inner oil groove, 53. Connecting oil passage, 6. Squirrel cage elastic support, 61. Trapezoidal tenon, 62. Elastic support oil seepage hole, 7. Oil supply hole, 8. Oil supply groove, 9. Metal bushing, 10. Bearing. Detailed Implementation

[0034] To clearly illustrate the technical features of this solution, the following detailed implementation method will be used to explain the solution.

[0035] like Figures 1-6 As shown, the present invention provides a multi-stage damping and squeezing oil film damper for suppressing steam cavitation, comprising a bearing 10, a squirrel cage elastic support 6, and a metal bushing 9 arranged sequentially from the inner ring to the outer ring. The metal bushing 9 is fixedly installed, and the inner ring of the bearing 10 is connected to the journal of the rotor, so the bearing 10 will follow the radial vibration of the rotor.

[0036] The metal bushing 9 has an oil supply hole 7 and an annular oil supply groove 8 on its inner ring. After the lubricating oil enters the oil supply groove 8 from the oil supply hole 7, it supplies oil to the inner ring of the metal bushing 9.

[0037] The outer ring of the elastic support 6 of the cage is fixed with an annular elastic oil reservoir 4. The elastic oil reservoir 4 is made of metal and is hollow. Its inner and outer walls are thin, allowing for elastic deformation. An annular second oil film 2 is formed within the elastic oil reservoir 4, thus the thickness of the second oil film 2 will vary. Figure 1 As shown, the inner length of the elastomer oil reservoir 4 is greater than the length of the squirrel cage elastic support 6. Here, length refers to... Figure 1 The left and right dimensions are such that when the elastic support 6 of the squirrel cage vibrates radially, it will cause a certain elastic deformation of the inner wall of the oil storage cavity 4 of the elastic body.

[0038] An annular third oil film 3 is formed between the outer ring of the elastomer oil reservoir 4 and the metal bushing 9. The oil supply groove 8 directly supplies oil to the third oil film 3. The second oil film 2 and the third oil film 3 are connected through a connecting hole assembly opened on the outer side of the outer ring of the elastomer oil reservoir 4. Figure 2 As shown, the outer connecting hole assembly includes two rows of outer ring oil leakage holes 41 disposed on the outer ring of the elastomer oil storage cavity 4, with multiple outer ring oil leakage holes 41 disposed in each row along the circumference.

[0039] When the third oil film 3 is full of lubricating oil, the lubricating oil flows through the outer ring oil seepage hole 41 to the elastomer oil storage cavity, filling the elastomer oil storage cavity with lubricating oil. The lubricating oil in the elastomer oil storage cavity serves as the second oil film 2. During the journal movement, the lubricating oil in the elastomer oil storage cavity can act as the second oil film in the damper, playing a role in being squeezed, thereby absorbing vibration energy.

[0040] A first oil film 1 is formed between the inner ring of the squirrel cage elastic support 6 and the bearing 10. The first oil film 1 and the second oil film 2 are connected by an inner connecting hole assembly formed in the inner ring of the squirrel cage elastic support 6 and the elastomer oil storage cavity 4. Figure 2 , 6 As shown, the inner connecting hole assembly includes two rows of inner ring oil seepage holes 42 disposed within the inner ring of the elastomer oil storage cavity 4. Each row of inner ring oil seepage holes 42 has multiple holes arranged circumferentially. The squirrel cage elastic support 6 has two rows of elastic support oil seepage holes 62, each row of elastic support oil seepage holes 62 having multiple holes arranged circumferentially and corresponding to the inner ring oil seepage holes 42. This allows the elastic support oil seepage holes 62 to communicate with the inner ring oil seepage holes 42, enabling lubricating oil to flow from the elastomer oil storage cavity to the first oil film 1.

[0041] In this embodiment, each row of outer ring oil seepage holes 41 has 8 holes arranged circumferentially, and each row of inner ring oil seepage holes 42 has 16 holes arranged circumferentially. The diameter of the outer ring oil seepage holes 41 is larger than the diameter of the inner ring oil seepage holes 42.

[0042] An oil sealing end cap 5 is fixedly connected to the end of the metal bushing 9 and fits against the end face of the bearing 10. The inner side of the oil sealing end cap 5 is positioned with the metal bushing 9 through an annular stepped end face, ensuring the concentricity of the oil sealing end cap 5.

[0043] The inner side of the oil-sealing end cap 5 has an inner oil groove 52 communicating with the first oil film 1 and an outer oil groove 51 communicating with the third oil film 3. Both the inner oil groove 52 and the outer oil groove 51 are annular grooves. The inner side of the oil-sealing end cap 5 has a connecting oil passage 53 connecting the inner oil groove 52 and the outer oil groove 51. The connecting oil passage 53 is provided in at least two parts and is evenly distributed along the circumference, such as... Figure 4 As shown, in this embodiment, there are two connecting oil passages 53.

[0044] The inner ring of the elastic oil reservoir 4 is fixed with multiple trapezoidal tenons 43, and the outer ring of the squirrel cage elastic support 6 has trapezoidal mortises 61 that are adapted to the trapezoidal tenons 43. The trapezoidal tenons 43 are inserted into the trapezoidal mortises 61 from the outer end of the squirrel cage elastic support 6. In this way, the elastic oil reservoir is fixed to the squirrel cage elastic support.

[0045] The cross-sectional area of ​​the trapezoidal tenon 61 gradually decreases from the outer end of the squirrel cage elastic support 6 inward, thereby restricting the displacement of the elastic body oil storage cavity 4 to the left. The outer end of the elastic body oil storage cavity 4 is in contact with the inner side of the oil sealing end cap 5, and the oil sealing end cap 5 will restrict the displacement of the elastic oil storage cavity to the right.

[0046] Method of using this invention:

[0047] In use, the metal bushing 9 is fixed, the inner ring of the bearing 10 is connected to the rotor, and lubricating oil enters through the oil supply hole 7. The lubricating oil flows through the oil supply hole 7 into the oil supply groove 8, which forms a buffer zone, allowing the lubricating oil to flow evenly to both sides of the third oil film, thus making the vibration damping effect of the third oil film more stable. The third oil film simultaneously supplies oil to both the second and first oil films. The third oil film supplies oil to the second oil film through the outer ring oil seepage hole 41 on the outer surface of the elastomer oil storage cavity 4.

[0048] The third oil film is connected to the outer oil groove of the sealing end cap. After the lubricating oil fills the third oil film, it flows to the outer oil groove of the sealing end cap. The lubricating oil in the outer oil groove flows to the inner oil groove through the connecting oil passage 53. The inner oil groove provides lateral oil supply to the first oil film, thus realizing that one oil supply hole can supply oil to three oil films at the same time. This simplifies the design of the oil supply path, makes the structure more compact, reduces costs, and improves the working efficiency of the damper. Since the second oil film is inside the closed elastomer oil storage cavity, no air is drawn into the second oil film. At the same time, the sealing end cap seals the first and third oil films, so that the lubricating oil can only flow out from one side. Meanwhile, the oil leakage hole 43 of the oil storage cavity is close to the oil outlet of the first oil film, which increases the oil film pressure at the oil outlet of the first oil film, reduces the amount of air drawn in from the side, avoids a large number of air bubbles in the lubricating oil, and improves the vibration reduction capacity of the damper.

[0049] The first oil film, acting as the primary vibration damping structure, is directly transferred to the first oil film when the rotor vibrates under unbalanced forces during high-speed rotation. The vibration load is transmitted through the journal to the outer ring of the bearing, which in turn compresses the first oil film. Therefore, compared to the other two oil films, the first oil film experiences the greatest compression, with the highest pressure in its positive pressure zone and the lowest pressure in its negative pressure zone. Within the positive pressure zone of the first oil film, the lubricating oil pressure is higher, and it flows through the inner connecting hole assembly to the elastomer's oil reservoir, thus reducing the compression of the first oil film in the positive pressure zone. Conversely, within the negative pressure zone, the lubricating oil pressure is lower, exceeding the pressure in the elastomer's oil reservoir. Consequently, the lubricating oil in the elastomer's oil reservoir flows through the inner connecting hole assembly to the first oil film, increasing the pressure in the negative pressure zone and thus suppressing the formation of vapor cavitation in the negative pressure zone of the first oil film.

[0050] The elastomer oil reservoir and the second oil film form the second-stage vibration damping structure. After passing through the first oil film, the vibration energy transmitted by the system decreases. When the load passes through the elastomer oil reservoir, the elastomer oil reservoir undergoes elastic deformation, and the second oil film takes effect. The compression degree of the second oil film is less than that of the first oil film. The third oil film acts as the third-stage vibration damping structure. After the load passes through the first and second oil films, the vibration response is greatly reduced, and the third oil film further reduces the vibration response of the system.

[0051] The first oil film of this invention reduces the vibration response of the rotor system itself, while the second and third oil films reduce the vibration response transmitted outward through the metal bushing. The three-layer oil film structure results in a progressively decreasing vibration response. Simultaneously, the thickness of each oil film is rationally controlled, solving the problems of single-layer oil films failing to meet vibration reduction requirements, and oil film thickness being too small leading to severe nonlinearity in stiffness. This suppresses the generation of vapor cavitation in the oil film, improving its stability and reliability.

[0052] Of course, the above description is not limited to the examples above. Technical features not described in this invention can be implemented by or using existing technology, and will not be repeated here. The above embodiments and drawings are only used to illustrate the technical solutions of this invention and are not intended to limit this invention. This invention has been described in detail with reference to preferred embodiments. Those skilled in the art should understand that any changes, modifications, additions or substitutions made by those skilled in the art within the scope of this invention do not depart from the spirit of this invention and should also fall within the scope of protection of the claims of this invention.

Claims

1. A multi-stage vibration-reducing squeeze-film damper for suppressing vapor cavitation, comprising, in order from an inner ring to an outer ring, a bearing (10), a squirrel-cage elastic support (6), and a metal bushing (9) having an oil supply hole (7) formed therein, characterized in that: The outer ring of the squirrel-cage elastic support (6) is fixed with an annular elastic body oil storage cavity (4), the elastic body oil storage cavity (4) is hollow and forms a second layer of oil film (2), a first layer of oil film (1) is formed between the inner ring of the squirrel-cage elastic support (6) and the bearing (10), a third layer of oil film (3) is formed between the outer ring of the elastic body oil storage cavity (4) and the metal bushing (9), the first layer of oil film (1) and the second layer of oil film (2) are communicated through an inner side communication hole assembly formed in the inner ring of the squirrel-cage elastic support (6) and the elastic body oil storage cavity (4), and the second layer of oil film (2) and the third layer of oil film (3) are communicated through an outer side communication hole assembly formed in the outer ring of the elastic body oil storage cavity (4).

2. A multi-stage vibration-reducing squeeze film damper with vapor cavity suppression according to claim 1, characterized in that: The outer side communication hole assembly comprises two rows of outer ring oil permeation holes (41) arranged on the outer ring of the elastic body oil storage cavity (4), and each row of outer ring oil permeation holes (41) is circumferentially provided with a plurality of outer ring oil permeation holes.

3. A multi-stage squeeze film damper with vapor cavity suppression according to claim 2, wherein: The inner side communication hole assembly comprises two rows of inner ring oil permeation holes (42) arranged on the inner ring of the elastic body oil storage cavity (4), and each row of inner ring oil permeation holes (42) is circumferentially provided with a plurality of inner ring oil permeation holes, and the squirrel-cage elastic support (6) is provided with two rows of elastic support oil permeation holes (62), each row of elastic support oil permeation holes (62) is circumferentially provided with a plurality of elastic support oil permeation holes (62) corresponding to the inner ring oil permeation holes (42).

4. A multi-stage vibration-reducing squeeze film damper with vapor cavity suppression according to claim 3, characterized in that: Each row of outer ring oil permeation holes (41) is circumferentially provided with 8 outer ring oil permeation holes, each row of inner ring oil permeation holes (42) is circumferentially provided with 16 inner ring oil permeation holes, and the diameter of the outer ring oil permeation hole (41) is greater than the diameter of the inner ring oil permeation hole (42).

5. A multi-stage vibration-reducing squeeze film damper with vapor cavity suppression in accordance with claim 1, wherein: The end of the metal bushing (9) is fixed with an oil sealing end cover (5) abutting against the end face of the bearing (10), the inner side of the oil sealing end cover (5) is provided with an inner oil groove (52) communicated with the first layer of oil film (1) and an outer oil groove (51) communicated with the third layer of oil film (3), and the inner side of the oil sealing end cover (5) is provided with a communication oil channel (53) communicated with the inner oil groove (52) and the outer oil groove (51).

6. A multi-stage squeeze film damper with vapor cavity suppression according to claim 5, wherein: The communication oil channel (53) is provided with at least two and is circumferentially distributed.

7. A multi-stage squeeze film damper with vapor cavity suppression according to claim 5, wherein: The inner ring of the elastic body oil storage cavity (4) is fixed with a plurality of ladder-shaped tenons (43), the outer ring of the squirrel-cage elastic support (6) is provided with ladder-shaped tenon grooves (61) matched with the ladder-shaped tenons (43), and the ladder-shaped tenons (43) are inserted into the ladder-shaped tenon grooves (61) from the outer end of the squirrel-cage elastic support (6).

8. A multi-stage vibration-reducing squeeze film damper for inhibiting vapour cavitation according to claim 7, wherein: The cross-sectional area of the ladder-shaped tenon groove (61) gradually decreases from the outer end of the squirrel-cage elastic support (6) to the inside, and the outer end of the elastic body oil storage cavity (4) abuts against the inner side of the oil sealing end cover (5).

9. A multi-stage vibration-reducing squeeze film damper for inhibiting vapour cavitation according to claim 5, wherein: The inner side of the oil sealing end cover (5) is positioned with the metal bushing (9) through an annular stepped end face.

10. A multi-stage vibration-reducing squeeze film damper for inhibiting vapor cavitation according to claim 1, wherein: The length of the inner cavity of the elastic body oil storage cavity (4) is greater than the length of the squirrel-cage elastic support (6).

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