A jet type elastic ring extrusion oil film damper

Abstract

The application discloses a jet type elastic ring extrusion oil film damper. The damper is arranged at a rotor bearing support position and mainly comprises a bearing seat, an outer oil film bushing, an elastic ring, a jet device and a bearing outer bushing. In the damper, the damping and vibration reduction effect is achieved by the flow of lubricating oil under the deformation of the elastic ring, the exchange of the flow among the jet device, the outer oil film and the oil cavity and the viscous effect. Compared with general elastic ring extrusion oil film dampers, the damper can not only improve the speed gradient of lubricating oil and the energy dissipation rate by using the jet device, but also can avoid stress concentration on the elastic ring to ensure a long service life of the structure. The damper has the advantages of compact structure, high damping and adjustable damping performance by changing the structural parameters of the jet device.

Description

Technical Field

[0001] This invention relates to the field of support damping technology for rotating machinery systems, and particularly to a jet-type elastic ring extrusion oil film damper. Background Technology

[0002] In rotating machinery systems such as aero-engines and gas turbines, the use of support damping structures remains the primary vibration control method to reduce rotor-induced vibrations and ensure reliable and long-life operation. Especially in recent years, with increasing technological and performance requirements, rotor operating speeds have also risen accordingly, often exceeding multiple critical speeds. Therefore, developing support damping structures suitable for high-speed rotors to reduce vibration response at critical points is of significant value for the engineering applications of rotating machinery systems.

[0003] Currently, the most widely used and thoroughly studied damper in aero-engines and gas turbines is the squeeze film damper (SFD). It has a relatively simple structure, long service life, and excellent damping effect, dissipating rotor vibration energy by utilizing the hydrodynamic lubrication principle of lubricating oil during bearing precession. However, the mechanical characteristics of the oil film formed by hydrodynamic lubrication are highly nonlinear functions of the rotor precession speed and radius. In high-speed rotor applications, it is very prone to "bistable" nonlinear abrupt responses. Simultaneously, the oil film is also prone to oscillation and instability at high speeds, leading to unstable and uncoordinated whirl responses in the rotor. These factors limit its application in high-speed rotors. To overcome the shortcomings of the squeeze film damper, the engineering community has proposed an elastic ring squeeze film damper (ERSFD). This damper incorporates an elastic ring structure within the oil film cavity to separate the cavity and avoid the generation of hydrodynamic nonlinear effects. Simultaneously, it has fine damping orifices machined on it, utilizing the throttling effect of lubricating oil flowing through the damping orifices to generate a damping effect. However, this structure still has some problems: First, holes need to be made in the elastic ring under alternating stress, and the edge of the hole is prone to high-cycle fatigue due to stress concentration, which greatly affects the service life of the elastic ring; Second, when the bearing moves, the inner bosses of the elastic ring moving in the opposite direction will separate, causing the lubricating oil to flow from the gap between the bosses instead of through the damping hole, reducing the damping effect; Finally, there is a large design contradiction between the damping effect and the support stiffness and service life, and it is often necessary to sacrifice the damping performance in order to ensure the support stiffness and service life. Summary of the Invention

[0004] To address the issues of limited elastic ring life and poor damping effect in traditional elastic ring extrusion oil film dampers used in high-speed rotor systems, this invention provides a jet-type elastic ring extrusion oil film damper. It innovatively proposes a jet-type outer ring design, utilizing jet flow to accelerate lubricating oil flow and improve flow damping, while avoiding the need for openings in the elastic ring, thereby extending the structural service life.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A jet-type elastic ring extrusion oil film damper includes a rotor journal, a bearing, an axial tightening nut, a bearing housing, an outer oil film bushing, an ejector, an elastic ring, an oil sealing O-ring, and a bearing bushing.

[0007] The bearing is mounted on the rotor journal and is axially fixed by an axially tightening nut.

[0008] The bearing housing is machined with an oil supply channel to provide lubricating oil with a certain pressure to the damper;

[0009] The outer oil film bushing and the jet injector are machined with flange edges and fixed by bolts and bearing seats; the outer oil film bushing is radially positioned by the interference fit cylindrical surface of the bearing seat, and the jet injector is radially positioned by the interference fit cylindrical surface of the outer oil film bushing.

[0010] The bearing outer ring bushing is fitted onto the bearing outer ring;

[0011] The elastic ring is assembled between the bearing outer ring bushing and the ejector. The inner and outer surfaces of the elastic ring are evenly distributed with several inner bosses and outer bosses along the circumference, and the positions of the inner bosses and outer bosses are staggered. The inner bosses are fitted with the bearing outer ring bushing, and the outer bosses are fitted with the functional section of the ejector.

[0012] The jet ejector includes functional sections, which are circumferentially segmented structures. The number of segments is the same as the number of outer protrusions of the elastic ring, and the inner surface of each segment mates with the outer protrusions of the elastic ring. At the same time, the functional sections are also used to form an inner oil film and an outer oil film.

[0013] The elastic ring is machined with a U-shaped groove, and a positioning pin is installed on one side of the outer oil film bushing to fix the elastic ring circumferentially.

[0014] Preferably, the bearing housing is mounted on the support structure of the rotating machinery and has at least one oil supply channel; the bearing housing is machined with threaded holes;

[0015] Preferably, the outer oil film bushing has a flanged edge machined on one axial side, which is fixed to the bearing housing by bolts and has an interference fit with the cylindrical surface of the bearing housing for radial positioning; a baffle is machined on the other side to form a sealed oil cavity, on which a positioning pin is installed; the outer oil film bushing has at least one oil inlet and one oil return port.

[0016] Preferably, the main body of the elastic ring is a thin-walled ring structure, with a plurality of inner and outer bosses alternately machined on the inner and outer cylindrical surfaces; the outer surface of the outer boss of the elastic ring mates with the jet injector, and the inner surface of the inner boss mates with the outer bushing of the bearing, thereby radially positioning the bearing; a U-shaped groove is machined on the elastic ring for mates with the positioning pin on the outer oil film bushing;

[0017] Preferably, one side of the jet ejector is machined with a flange, which is fixed to the bearing housing together with the outer oil film bushing by bolts, and radially positioned with the outer oil film bushing by a cylindrical interference fit; the jet ejector is machined with a baffle to form an oil cavity; the functional section of the jet ejector has a radially converging slit.

[0018] Preferably, the convergent slit size parameters and jet angle of the jet ejector can be used as design parameters to adjust the damping effect;

[0019] Preferably, the jet ejector is fixed to the bearing housing and radially positioned by a connecting structure, and includes functional segments. The functional segments are circumferentially segmented, and the segments form a converging gap. The gap connects the inner oil film and the outer oil film. The width of the gap on the inner oil film side is greater than the width on the outer oil film side, and both sides of the gap are located in the same radial direction. When the lubricating oil flows from the inner oil film to the outer oil film, the lubricating oil flow channel formed by the gap is converging, and the flow is in the radial direction.

[0020] Preferably, the jet ejector is fixed to the bearing housing and radially positioned by a connecting structure, and includes functional segments. The functional segments are circumferentially segmented, and the segments form converging gaps. The width of the gap on the inner oil film side is larger than that on the outer oil film side. At the same time, the gaps on the inner oil film side and the gaps on the outer oil film side are not in the same radial direction, so that the jet after the lubricating oil flows through the gap has a tangential component in the outer oil film, thereby increasing the circumferential flow velocity of the lubricating oil in the outer oil film and improving the flow damping in the outer oil film.

[0021] As an optimization, the outer surface of the jet annular segment can be machined with a baffle plate and circumferentially machined with damping holes to enhance the damping effect;

[0022] Preferably, the bearing outer ring bushing is interference-fitted onto the bearing outer ring, and grooves for installing oil sealing O-rings are machined on both axial end faces;

[0023] Compared with existing elastic ring extrusion oil film dampers, the present invention has the following advantages:

[0024] (1) In this invention, the elastic ring does not need to be machined with small holes, which greatly reduces the stress concentration on the structure compared with the structure with small holes, thereby improving the fatigue life and service life of the elastic ring.

[0025] (2) In this invention, the elastic ring damper accelerates the flow of lubricating oil through the jet hole, increases the lubricating oil velocity gradient and thus increases the flow loss, and can further damping dissipate by utilizing the kinetic energy loss of the jet impacting the wall.

[0026] (3) In this invention, the jet ejector can improve its damping capability by adding a baffle plate with damping holes;

[0027] (4) In this invention, the damping effect is avoided from the loss caused by the separation of the boss due to the movement of the elastic ring. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the overall structure of a jet-type elastic ring extrusion oil film damper according to the present invention;

[0030] Figure 2 This is a schematic diagram of an elastic ring structure;

[0031] Figure 3 A schematic diagram of the cross-section of a jet-type elastic ring extrusion oil film damper in one embodiment;

[0032] Figure 4 A three-dimensional structural diagram of the jet ejector in one embodiment;

[0033] Figure 5 This is a schematic diagram of lubricating oil flowing in the jet orifice when the elastic ring is compressed in one embodiment;

[0034] Figure 6 This is a schematic diagram of the cross-section of the oblique jet type elastic ring extrusion oil film damper in another embodiment;

[0035] Figure 7 This is a three-dimensional structural diagram of the oblique flow jet in another embodiment;

[0036] Figure 8 This is a schematic cross-sectional view of a jet-type elastic ring extrusion oil film damper with a baffle plate design in another embodiment.

[0037] Figure 9 This is a three-dimensional structural diagram of an ejector with a flow-blocking plate design in another embodiment. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] To clearly illustrate the technical features of this patent, the invention will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0041] like Figure 1 As shown, a jet-type elastic ring extrusion oil film damper of the present invention includes a rotor journal 1, a bearing 2, an axial tightening nut 3, a bearing seat 4, an outer oil film bushing 7, an ejector 11, an elastic ring 13, an oil sealing O-ring 14, and a bearing outer ring bushing 15.

[0042] The bearing 2 is mounted on the rotor journal 1 and is axially fixed by the axial tightening nut 3.

[0043] The bearing housing 4 is part of the load-bearing system, which realizes the transmission of the support load. It has an oil supply channel 5 machined on it to provide lubricating oil with a certain pressure to the damper.

[0044] Both the outer oil film bushing 7 and the ejector 11 are machined with flange edges and are fixed by bolts 6 and bearing housing 4. The outer oil film bushing 7 is radially positioned by the interference fit cylindrical surface of the bearing housing 4, and the ejector 11 is radially positioned by the interference fit cylindrical surface of the outer oil film bushing 7. The outer oil film bushing 7 is provided with an oil supply hole 8, the position of which matches the oil supply channel 5 on the bearing housing 4, for supplying oil and providing oil pressure to the inner oil film 16 and the outer oil film 9 in the damper of the present invention.

[0045] The bearing outer ring bushing 15 is assembled on the bearing outer ring. The elastic ring 13 is assembled between the bearing outer ring bushing 15 and the ejector 11, and its structure is as follows: Figure 2As shown, the inner boss 19 mates with the bearing outer ring bushing 15, and the outer boss 20 mates with the functional section 12 of the ejector 11. A U-shaped groove 22 is machined on the elastic ring 13, and a locating pin 10 is installed on one side of the outer oil film bushing 7, thereby enabling the elastic ring 13 to be circumferentially fixed using the locating pin 10 to prevent circumferential movement during operation. The force transmission route for the supporting load is: bearing 2 - bearing outer ring bushing 15 - elastic ring 13 - ejector 11 - outer oil film bushing 7 - bearing seat 4. The structural design of the elastic ring 13 is the main way to adjust the stiffness of the elastic support.

[0046] The outer oil film bushing 7 and the ejector 11 have baffles machined on both sides of the elastic ring 13, and oil-sealing O-rings 14 are installed on both axial sides of the bearing outer ring bushing 15, thus forming a closed oil cavity structure. The gap between the ejector 11 and the outer oil film bushing 7 constitutes the outer oil film 9 of the oil cavity; the gap between the ejector 11 and the elastic ring 13 constitutes the inner oil film 16 of the oil cavity, such as... Figure 3 As shown, the inner oil film 16 is divided into several sub-oil cavities by the outer boss 20 of the elastic ring 13 in the circumferential direction. The sub-oil cavities are not directly connected to each other. The several inner cavities 17 formed by the elastic ring 13, the bearing outer bushing 15, and the inner boss 19 are not connected to each other and are not connected to the inner oil film 16. The oil supply hole 8 is directly connected to the outer oil film 9. The lubricating oil fills the outer oil film 9 through the oil supply hole 8 and flows into the various sub-oil cavities of the inner oil film 16 through the gap 18, thereby achieving oil supply to the inner oil film 16 and the outer oil film 9.

[0047] like Figure 3 , Figure 4 As shown, in one embodiment of the present invention, the functional segment 12 of the first jet injector 11A has a discontinuous feature of circumferential segmentation, and there is a gap 18 between the circumferential segments. This gap 18 connects the inner oil film 16 and the outer oil film 9. The width of the gap 18 on the inner oil film 16 side is larger than the width on the outer oil film 9 side, and the two sides of the gap are located in the same radial direction. When lubricating oil flows from the inner oil film 16 to the outer oil film 9, the lubricating oil flow channel formed by the gap 18 is converging and the flow is in the radial direction.

[0048] like Figure 5 As shown, when the rotor moves laterally, the outer ring bushing 15 of the bearing also responds with lateral movement under the drive of the bearing 2, thereby squeezing the elastic ring 13 and causing radial deformation. At this time, the volume of one side of the inner oil film 16 decreases, causing the lubricating oil to flow out from the converging gap 18. According to the continuity equation of incompressible fluids in fluid mechanics:

[0049] V2=A1V1 / A2 (1)

[0050] In the formula, V1 and V2 represent the inlet and outlet velocities of the flow channel, respectively, and A1 and A2 are the inlet and outlet cross-sectional areas of the flow channel, respectively. It can be seen that when lubricating oil flows out of the inner oil film 16, the converging gap 18 accelerates the flow of lubricating oil, forming a relatively high-speed jet after the oil film is compressed, and flowing into the outer oil film 9. During rotor vibration, the damping mechanism is as follows:

[0051] (1) When the lubricating oil flows in the narrow, converging gap 18, due to its high viscosity, the viscous friction generated by the wall resistance causes a velocity gradient in the normal direction of the fluid. At this time, shear stress acts on the viscous fluid control volume:

[0052]

[0053] In the formula, μ is the viscosity coefficient. The velocity gradient is the normal velocity gradient along the wall. The higher the flow velocity, the stronger this viscous friction, and the greater the kinetic energy loss. That is, the converging gap 18 can amplify this loss.

[0054] (2) When the lubricating oil flows out of the converging gap 18, the flow channel area expands, which leads to an increase in flow pressure and forms a pressure difference effect that hinders fluid flow, thereby playing a damping role.

[0055] (3) The jet after the exit of the converging slit 18 impacts the wall and its velocity decreases, resulting in kinetic energy loss and playing a damping role.

[0056] (4) The circumferential flow of fluid in the narrow gap within the outer oil film 9 will also generate a certain viscous friction force, resulting in damping and dissipation.

[0057] (5) When the lubricating oil flows into the inner oil film 16 through the outer oil film 9, the gap 18 plays a throttling function and can also play a damping and dissipation role.

[0058] In the design, the damping effect of the damper is affected by the structural parameters of the elastic ring 13, the size parameters of the converging gap 18, and the thickness of the outer oil film 9.

[0059] The jet angle of the converging slit 18 can also be used as a design parameter to adjust the damping effect. In another embodiment, combined with Figure 6 In this embodiment, the second jet injector 11B is as follows: Figure 7 As shown. In this embodiment, the width of the slit 18 on the inner oil film 16 side is larger than the width on the outer oil film 9 side. At the same time, the slits on the inner oil film 16 side and the outer oil film 9 side are not in the same radial direction, so that the jet of lubricating oil after flowing through the slit 18 has a tangential component in the outer oil film 9, thereby increasing the circumferential flow velocity of the lubricating oil in the outer oil film 9 and improving the flow damping in the outer oil film 9.

[0060] Further optimize the plan, combined with Figure 8 And the structure of the third jet 11C in this embodiment is as follows: Figure 9 As shown in the diagram, a baffle plate 21 is machined on the outer side of the functional section 12 of the third jet injector 11C. The baffle plate 21 separates the outer oil film 9, and circumferential damping holes 23 are machined on the baffle plate 21 to increase the flow resistance of the lubricating oil in the outer oil film 9. When the lubricating oil flows in the outer oil film 9 after being accelerated by the third jet injector 11C, the throttling effect of the damping holes 23 can further enhance the damping effect of the damper.

[0061] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A jet-type elastic ring extrusion oil film damper, characterized in that: It includes a rotor journal (1), a bearing (2), an axial tightening nut (3), a bearing housing (4), an outer oil film bushing (7), an ejector (11), an elastic ring (13), an oil sealing O-ring (14), and a bearing outer ring bushing (15). The bearing (2) is mounted on the rotor journal (1) and is axially fixed by an axially tightening nut (3); The bearing housing (4) is machined with an oil supply channel (5) to provide lubricating oil with a certain pressure to the damper; The outer oil film bushing (7) and the jet injector (11) are machined with flange edges and are fixed by bolts (6) and bearing seats (4); the outer oil film bushing (7) is radially positioned by the interference fit cylindrical surface of the bearing seat (4), and the jet injector (11) is radially positioned by the interference fit cylindrical surface of the outer oil film bushing (7). The bearing outer ring bushing (15) is assembled on the bearing outer ring; The elastic ring (13) is assembled between the bearing outer ring bushing (15) and the jet injector (11). The inner and outer surfaces of the elastic ring (13) are evenly distributed with a number of inner bosses (19) and outer bosses (20) along the circumference, and the positions of the inner bosses (19) and outer bosses (20) are staggered. The inner bosses (19) cooperate with the bearing outer ring bushing (15), and the outer bosses (20) cooperate with the functional section (12) of the jet injector (11). The jet ejector (11) includes a functional section (12), which is a circumferentially segmented structure. The number of segments is the same as the number of outer protrusions (20) of the elastic ring (13). The inner surface of each segment is engaged with the outer protrusions (20) of the elastic ring (13). At the same time, the functional section (12) is also used to form an inner oil film (16) and an outer oil film (9). The elastic ring (13) is machined with a U-shaped groove (22), and a positioning pin (10) is installed on one side of the outer oil film bushing (7) to fix the elastic ring (13) circumferentially. The cross section of the functional segment (12) of the jet ejector (11) has a circumferential discontinuous feature, and the gap between each circumferential segment is a convergent gap (18). The converging slit (18) connects the inner oil film (16) and the outer oil film (9). The outer oil film bushing (7) and the jet ejector (11) are machined with baffles on both sides of the elastic ring (13), and at the same time, the bearing outer ring bushing (15) is equipped with oil sealing O-rings (14) on both sides of the axial direction to form a closed oil cavity; The gap between the jet ejector (11) and the outer oil film bushing (7) forms the outer oil film (9) of the oil cavity; the gap between the jet ejector (11) and the elastic ring (13) forms the inner oil film (16) of the oil cavity; the inner oil film (16) is divided into several sub-oil cavities by the outer boss of the elastic ring in the circumferential direction.

2. The jet-type elastic ring extrusion oil film damper according to claim 1, characterized in that: When the rotor moves laterally, the outer ring bushing (15) of the bearing also moves laterally under the drive of the bearing (2), which compresses the elastic ring (13) and causes it to deform, reducing the volume of the sub-oil cavity on one side of the inner oil film (16), so that the lubricating oil in it flows out from the converging gap (18).

3. The jet-type elastic ring extrusion oil film damper according to claim 1, characterized in that: The jet angle of the converging slit (18) of the jetter (11) can be adjusted so that the jet has a relatively larger tangential component in the outer oil film (9) to increase the circumferential flow velocity of the lubricating oil in the outer oil film (9).

4. A jet-type elastic ring extrusion oil film damper according to claim 1 or 2, characterized in that: The jet ejector is fixed to the bearing housing (4) and radially positioned by a connecting structure, and includes a functional section (12). The functional section (12) is a circumferentially segmented structure, and the segments form a converging gap (18). The gap (18) connects the inner oil film (16) and the outer oil film (9). The width of the gap (18) on the inner oil film (16) side is greater than the width on the outer oil film (9) side, and the two sides of the gap are located in the same radial direction. When the lubricating oil flows from the inner oil film (16) to the outer oil film (9), the lubricating oil flow channel formed by the gap (18) is converging and the flow is in the radial direction.

5. A jet-type elastic ring extrusion oil film damper according to claim 1 or 2, characterized in that: The jet ejector is fixed to the bearing housing (4) and radially positioned by a connecting structure, and includes a functional section (12). The functional section (12) is a circumferentially segmented structure, and the segments form a converging gap (18). The width of the gap (18) on the inner oil film (16) side is larger than the width on the outer oil film (9) side. At the same time, the gap on the inner oil film (16) side and the gap on the outer oil film (9) side are not in the same radial direction, so that the jet after the lubricating oil flows through the gap (18) has a tangential component in the outer oil film (9), thereby increasing the circumferential flow velocity of the lubricating oil in the outer oil film (9) and improving the flow damping in the outer oil film (9).

6. A jet-type elastic ring extrusion oil film damper according to claim 1 or 2, characterized in that: The outer side of the functional section (12) of the jet injector is processed with a flow-blocking plate (21) and a circumferential damping hole (23) is processed on it; when the lubricating oil is accelerated by the jet injector and flows in the outer oil film (9), the throttling effect of the damping hole (23) enhances the damping effect of the damper.

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