Rigidity suppression and damping enhancement type squeeze film damper

Abstract

The invention relates to a rigidity suppression and damping enhancement type squeeze film damper which comprises a damper outer ring, a damper inner ring and two sealing expansion rings located between the damper outer ring and the damper inner ring, an oil film is formed between the damper outer ring and the damper inner ring, an oil supply hole communicated to the oil film is formed in the damper outer ring, and the oil supply hole is communicated with the oil film. The sealing device is characterized in that an annular groove is formed in the outer circle of the damper inner ring, the sealing expansion rings are located in the annular groove, a plurality of bosses distributed in the circumferential direction are arranged between the sides, away from each other, of the two sealing expansion rings and the annular groove, and a plurality of leakage grooves distributed in the circumferential direction are formed in the sealing expansion rings. After the leakage channel is innovatively and additionally arranged on the first sealing face or the second sealing face, the amplitude of oil film force is obviously reduced, the mechanical vector of the oil film force is obviously deviated in the tangential direction, then the rigidity of the oil film is greatly reduced, the structural improvement effectively optimizes the dynamic performance of a system by changing the distribution characteristic of the oil film force, and the service life of the system is prolonged. And a good inhibition effect is achieved on the generation of steam cavitation.

Description

Technical Field

[0001] The present invention relates to the technical field of sealing mechanisms, in particular to a stiffness-suppressed and damping-enhanced squeeze film damper. Background Art

[0002] Squeeze film dampers (SFDs) are commonly used in rotor system supports to reduce rotor vibration. However, as rotors move toward higher speeds and thrust-to-weight ratios, these systems place higher demands on the damping performance of SFDs. To meet this demand, sealing rings are often added to both ends of the SFD to improve its overall performance and stability.

[0003] The sealing ring is designed with an opening and has good elasticity. In the free state, the sealing ring is not a perfect circle, but when it is installed inside the ring groove and squeezed by the outer ring of the SFD, the sealing ring will be compressed and deformed into a perfect circle. Figure 9 shown.

[0004] After the sealing expansion ring is assembled into the ring groove, its outer surface fits tightly with the inner wall of the SFD outer ring by virtue of its own elastic deformation characteristics, forming the first sealing surface, which effectively blocks the axial leakage of lubricating oil. When the system oil pressure is established, the expansion ring is driven by the fluid pressure to move toward the outside of the ring groove, so that its side wall and the side wall of the ring groove can achieve surface contact sealing, constructing the second sealing surface, further blocking the axial leakage path of lubricating oil. The two sealing surfaces work together to form a double sealing structure, which significantly improves the sealing performance. The installation layout of the expansion ring and the composition of the sealing surface are as follows: Figure 2 shown.

[0005] The synergistic effect of the dual sealing surfaces allows the primary oil outflow path to be concentrated through the expansion ring gap and the pre-set oil leak hole, allowing outside air to enter the SFD through these channels. Compared to open SFDs without end seals, this structure significantly reduces the oil outflow path, effectively suppressing axial oil flow. This optimized design allows the oil to be more fully squeezed within the SFD, significantly increasing oil film pressure. Furthermore, the sealing surface configuration significantly reduces air intake, effectively maintaining the integrity of the oil film and preventing degradation of oil film performance due to gas-liquid two-phase flow, thus ensuring enhanced vibration damping performance of the SFD.

[0006] Disadvantages of squeeze film damping with sealing ring during operation: (1) The oil film stiffness is too large.

[0007] The introduction of a sealing expansion ring at the end of the SFD significantly increases the oil film force, significantly broadens the dynamic pressure range of the oil film, and changes the oil film pressure distribution. This increase in the dynamic pressure range of the oil film significantly increases the oil film stiffness and damping. This increase in oil film stiffness introduces additional mass at the rotor pivot point, affecting the rotor's operational stability and safety.

[0008] (2) The integrity of the oil film is reduced.

[0009] The expanded dynamic pressure range of the oil film makes it easier for the oil film pressure to reach the saturated vapor pressure of the lubricating oil, triggering steam cavitation. The presence of steam cavitation damages the integrity of the oil film, thereby weakening its dynamic characteristics. Furthermore, excessive steam can erode the damper's inner ring surface, reducing the service life of the SFD.

[0010] (3) Oil film stiffness suppression and steam suppression technologies are not yet mature At present, the research field of SFD dynamic characteristics shows a significant research bias. The research focus is mostly on the exploration of oil film damping improvement technology, while the research on oil film stiffness weakening is relatively scarce, and a systematic and efficient oil film stiffness suppression technology system has not yet been formed.

[0011] While a range of steam suppression technologies have been developed to control steam cavitation, they are generally inadequately adapted to the demanding engineering requirements of SFD. Existing steam suppression solutions often struggle to meet the multiple requirements of SFD for compactness, operational stability, and environmental adaptability, resulting in low engineering conversion efficiency. This significantly hinders their adoption in practical industrial applications, necessitating the development of comprehensive solutions that combine theoretical innovation with engineering feasibility. Summary of the Invention

[0012] In view of the deficiencies in the prior art, the present invention provides a stiffness-suppressed and damping-enhanced squeeze film damper.

[0013] The present invention is achieved through the following technical solution, which provides a stiffness-suppressed and damping-enhanced squeeze oil film damper, including a damper outer ring, a damper inner ring, and two sealing expansion rings located between the damper outer ring and the damper inner ring. An oil film is formed between the damper outer ring and the damper inner ring, and an oil supply hole connected to the oil film is opened on the damper outer ring. It is characterized in that: the outer ring of the damper inner ring is opened with an annular groove, the sealing expansion ring is located in the annular groove, and a plurality of circumferentially arranged bosses are provided between the side of the two sealing expansion rings away from each other and the annular groove, and a plurality of circumferentially arranged leakage grooves are opened on the sealing expansion ring, and the leakage grooves penetrate along the thickness direction of the sealing expansion ring.

[0014] As an optimization, the boss is fixedly connected to the inner wall of the annular groove.

[0015] As an optimization, the protrusion height of the boss is 0.01 mm-0.1 mm.

[0016] As an optimization, the boss forms a gap of 0.01 mm to 0.1 mm between the sealing expansion ring and the annular groove.

[0017] As an optimization, the leakage groove is arranged on the outer ring of the sealing expansion ring.

[0018] As an optimization, the leakage groove is in the shape of an elongated strip and extends along the circumference of the sealing expansion ring.

[0019] As an optimization, the inner ring of the damper outer ring is provided with an oil supply groove located between the two sealing expansion rings, and the oil supply hole is connected to the oil supply groove.

[0020] As an optimization, a first sealing surface is formed between the outer ring of the sealing expansion ring and the inner ring of the damper outer ring.

[0021] As an optimization, the cross section of the sealing expansion ring is rectangular.

[0022] As an optimization, a docking notch is provided on the sealing expansion ring, and the sealing expansion ring fits with the inner ring of the damper outer ring through its own elastic force.

[0023] The beneficial effects of the present invention are: (1) By innovatively adding leakage channels to the first or second sealing surface, the oil film force amplitude is significantly reduced, and its mechanical vector shifts significantly in the tangential direction, thereby significantly reducing the oil film stiffness. This structural improvement effectively optimizes the system's dynamic performance by changing the distribution characteristics of the oil film force.

[0024] (2) The introduction of an additional leakage channel significantly enhances the axial fluidity of the lubricating oil. This design reduces the squeeze effect on the lubricating oil and reduces the oil film pressure level. This pressure regulation mechanism effectively suppresses the generation of steam cavitation, improving the stability and reliability of system operation.

[0025] (3) Based on the regulation of the direction of the oil film force, SFD can effectively reduce the stiffness while still maintaining a high level of damping performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a cross-sectional schematic diagram of the present invention; Figure 2 It is a partial cross-sectional view of the prior art; Figure 3 It is a cross-sectional schematic diagram of the position of the expansion ring of the present invention; Figure 4 It is a structural schematic diagram of the expansion ring of the present invention; Figure 5 A schematic diagram comparing the prior art and the present invention; Figure 6 A schematic diagram showing a simulation comparison between the prior art and the present invention; Figure 7 Schematic diagram comparing the oil film force simulation of the prior art and the present invention; Figure 8 is a flow chart of the design method of the present invention; Figure 9 This is a physical picture of the expansion ring in the prior art; As shown in the figure: 1. Damper outer ring, 2. Damper inner ring, 3. Sealing expansion ring, 4. Bearing, 5. Rotating shaft, 6. Oil supply hole, 7. Oil supply groove, 8. Oil film, 9. Ring groove, 10. Boss, 11. Leakage groove, 12. First sealing surface, 13. Second sealing surface. DETAILED DESCRIPTION

[0027] In order to clearly illustrate the technical features of this solution, this solution is described below through specific implementation methods.

[0028] like Figures 1 to 9 As shown, the stiffness suppression and damping enhanced squeeze film damper of the present invention includes a damper outer ring 1, a damper inner ring 2 and two sealing expansion rings 3 located between the damper outer ring 1 and the damper inner ring 2. The damper outer ring 1 is fixedly arranged, and the damper inner ring 2 is connected through an elastic squirrel cage, thereby achieving radial movement through the elastic deformation of the elastic squirrel cage. The inner ring of the damper inner ring 2 is connected to the rotating shaft 5 through a bearing 4, thereby achieving support of the squeeze film damper on the rotating shaft 5 to reduce the amplitude of the rotating shaft 5.

[0029] like Figure 2 As shown, an oil film 8 is formed between the damper outer ring 1 and the damper inner ring 2. The inner ring of the damper outer ring 1 has an oil supply groove 7 located between the two sealing expansion rings 3. The damper outer ring 1 has an oil supply hole 6, which is connected to the oil supply groove 7, thereby achieving communication between the oil supply hole 6 and the oil film 8. Lubricating oil is supplied to the oil film through the oil supply hole 6. The oil supply groove 7 realizes oil supply in a circumferential direction to the entire oil film 8.

[0030] like Figure 4 As shown, the cross section of the sealing expansion ring 3 is rectangular. Figure 2 As shown, the outer ring of the damper inner ring 2 has an annular groove 9, and the sealing ring 3 is located within the annular groove 9. The annular groove 9 has a rectangular cross-section, and its length and width are both larger than those of the sealing ring 3. The sealing ring 3 has a docking notch, and the sealing ring 3 fits against the inner ring of the damper outer ring 1 through its own elastic force. This forms a first sealing surface 12 between the outer ring of the sealing ring 3 and the inner ring of the damper outer ring 1.

[0031] like Figure 4As shown, the sealing ring 3 is provided with a plurality of circumferentially arranged leakage grooves 11, which extend through the thickness of the sealing ring 3. The leakage grooves 11 are provided on the outer ring of the sealing ring 3. The leakage grooves 11 are elongated and extend circumferentially along the sealing ring 3, thereby allowing lubricating oil to pass through the first sealing surface 12 at multiple locations along the circumference.

[0032] In the prior art, a second sealing surface 13 is formed between the side of the two sealing rings 3 that are away from each other and the annular groove 9. In the present application, a plurality of circumferentially arranged bosses 10 are provided between the side of the two sealing rings 3 that are away from each other and the annular groove 9, and the bosses 10 are fixedly connected to the inner wall of the annular groove 9. The protrusion height of the bosses 10 is 0.01 mm -0.1 mm. As a result, the bosses 10 form a gap of 0.01 mm -0.1 mm between the sealing ring 3 and the annular groove 9, thereby destroying the second sealing surface 13 and causing the second sealing surface to fail. As a result, the lubricating oil is able to bypass the seal of the sealing ring 3 and directly flow out of the SFD, causing the axial flow of the lubricating oil to be significantly intensified. This enhanced axial flow effect weakens the pressure accumulation inside the oil film, causing the overall pressure level of the oil film to drop, while raising the pressure value of the negative pressure zone. This change in pressure distribution effectively suppresses the generation of steam cavitation inside the oil film.

[0033] Oil film stiffness and damping are the core parameters of SFD dynamic performance, which are respectively related to oil film force F Radial force F r , tangential component F t When the flow state of the lubricating oil inside the SFD is significantly adjusted by structural optimization, the direction of the oil film force will generate a tangential force. F t This change directly leads to the radial component of the oil film force F r Effectively reduce, thereby achieving precise control of oil film stiffness. By actively intervening in the flow characteristics of lubricating oil, the oil film stiffness and damping parameters can be optimized.

[0034] Although the failure of the second sealing surface will cause the oil film force amplitude to decrease to a certain extent, thanks to the optimization adjustment of the oil film force direction, its tangential component F t When the structural dimensions of the boss 10 are designed to the appropriate range, the tangential component of the force F t Instead, it achieved positive growth, ensuring that SFD maintained its operation in a high-efficiency range.

[0035] In this application, the introduction of an additional oil leakage channel within the traditional expansion ring-sealed SFD structure achieves multiple performance optimizations: by regulating the oil flow path, the oil film stiffness is significantly reduced, effectively suppressing the occurrence of steam cavitation; simultaneously, by optimizing the direction of the oil film force, the oil film damping is significantly enhanced. This innovative, multi-dimensional performance improvement strategy successfully overcomes the technical bottleneck of the difficult coordinated optimization of oil film stiffness and damping. While improving the oil film damping performance, it effectively reduces the oil film stiffness, providing a new solution for the optimized design of SFDs.

[0036] Similarly, designing an additional leakage channel (leakage groove 11) on the first sealing surface can also achieve the purpose of reducing the oil film stiffness, maintaining or even improving the oil film damping, and suppressing steam cavitation.

[0037] The design process of the present invention: During the operation of a squeeze film damper (SFD), the lubricating oil, under the dual effects of squeeze and viscosity, forms positive and negative pressure zones within the damper. These two effects work together to generate oil film force. By decomposing the oil film force tangentially and radially, we can derive the tangential force component, which influences the film's damping characteristics, and the radial force component, which determines the film's stiffness. For SFDs with good sealing performance, the direction of the oil film force is more radial, resulting in higher film stiffness. By artificially adding oil leakage channels, the overall amplitude of the oil film force is reduced while also causing the force to deflect tangentially. Although the total amount of oil film force is reduced, this adjustment significantly increases the proportion of the tangential force component, effectively improving the film's damping performance. The combined effects of the reduced amplitude and directional deflection of the oil film force significantly reduce the radial force component, effectively suppressing the film's stiffness. In addition, the reduction in oil film force directly leads to a narrowing of the fluctuation range of the oil film dynamic pressure, which significantly reduces the area where the oil film pressure drops to the saturated vapor pressure of the lubricating oil, thereby achieving the effect of suppressing the oil film cavitation phenomenon and improving the operating stability and reliability of the SFD.

[0038] To effectively control the stiffness and damping characteristics of a squeeze film damper, the design of an oil leakage path can be optimized based on the dual sealing mechanism of the expander ring. During operation, the expander ring forms a primary sealing surface and a secondary sealing surface. Targeting these two critical sealing areas, leakage paths can be added by designing the expander ring's surface structure.

[0039] In the optimized design of the first sealing surface, a directional leakage channel can be constructed by machining a lubricating oil leakage groove of specific specifications on the outer ring surface of the expansion ring. For the second sealing surface, a lubricating oil leakage groove can be opened on the side wall of the expansion ring to expand the leakage channel. In addition, the axial positioning technology of the expansion ring is innovatively used to weaken the sealing function of the second sealing surface by precisely controlling the axial position of the expansion ring in the ring groove, thereby opening up an additional leakage channel. This multi-dimensional design strategy not only fully utilizes the structural characteristics of the expansion ring, but also effectively realizes the precise control of lubricating oil leakage by actively intervening in the sealing performance of the expansion ring, providing an effective technical approach for the design of stiffness suppression and damping enhanced squeeze film dampers. The design scheme of the stiffness suppression and damping enhanced squeeze film damper proposed in the patent of this invention is as follows: Figure 8 shown.

[0040] Simulation analysis of the present invention: In order to verify the feasibility of the design of the SFD with stiffness suppression and damping enhancement, a conventional expansion ring sealed SFD and a SFD with stiffness suppression and damping enhancement designed by changing the axial position of the expansion ring were established. Among them, the width between the expansion ring and the side wall of the SFD with stiffness suppression and damping enhancement is 0.03mm. The structural diagram is shown in the figure below. Figure 5 shown.

[0041] The corresponding CFD numerical simulation model was established, and numerical simulation calculations were performed under the working conditions of 600Hz and 0.5 eccentricity. The oil film pressure cloud diagram obtained by numerical simulation is as follows: Figure 6 shown Will Figure 6 Comparative analysis of numerical simulation results reveals significant differences in the pressure contours of the stiffness-suppressed and damping-enhanced SFD compared to conventional squeeze film dampers (SFDs). The dark blue region, representing the low-pressure area of the oil film, is significantly reduced, visually demonstrating a significantly narrowed range of oil film pressure fluctuations for this type of SFD, further confirming the effective reduction in oil film pressure amplitude. Furthermore, observation revealed a significant shift in the spatial position of the low-pressure region along the journal's precession direction, revealing a corresponding shift in the direction of the oil film force.

[0042] The oil film force of SFD can be calculated by integrating the oil film pressure F and its tangential component F t and radial force F r The oil film force coefficient obtained by numerical simulation is as follows: Figure 7 shown.

[0043] Through Figure 7The analysis of the oil film force simulation data shows that compared with the traditional structure, the stiffness suppression and damping enhancement SFD presents unique mechanical characteristics: the overall force of the oil film F The tangential force directly related to the oil film damping characteristics F t The radial force, which reflects the stiffness of the oil film, has been significantly improved, with its value increasing from 1113N to 1729N, an increase of 57.6%. F r The force of the oil film on the new SFD is significantly reduced from 2318N to 1755N, a decrease of 24.3%. This significant change in mechanical parameters fully verifies that the oil film force vector of the new SFD has shifted significantly in the tangential direction. This change in mechanical properties coincides with the Figure 6 The spatial position offset phenomenon of the high and low pressure areas of the oil film presented in the paper forms a corresponding relationship, and the two confirm each other, jointly revealing the optimization mechanism and action mechanism of the stiffness suppression and damping enhanced SFD in fluid dynamic characteristics.

[0044] Of course, the above description is not limited to the above examples. Technical features not described in the present invention can be achieved by or by adopting existing technologies, which will not be described here. The above embodiments and drawings are only used to illustrate the technical solutions of the present invention and are not limitations of the present invention. The present invention is described in detail with reference to the preferred implementation methods. Ordinary technicians in this field should understand that changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention do not depart from the purpose of the present invention and should also fall within the scope of protection of the claims of the present invention.

Claims

1. A stiffness-suppressed and damping-enhanced squeeze film damper, comprising a damper outer ring (1), a damper inner ring (2), and two sealing expansion rings (3) located between the damper outer ring (1) and the damper inner ring (2), an oil film (8) being formed between the damper outer ring (1) and the damper inner ring (2), an oil supply hole (6) being opened on the damper outer ring (1) and connected to the oil film (8), and characterized in that: The outer ring of the damper inner ring (2) is provided with an annular groove (9), the sealing expansion ring (3) is located in the annular groove (9), and a plurality of circumferentially arranged bosses (10) are provided between the sides of the two sealing expansion rings (3) that are away from each other and the annular groove (9), and the sealing expansion ring (3) is provided with a plurality of circumferentially arranged leakage grooves (11), and the leakage grooves (11) penetrate along the thickness direction of the sealing expansion ring (3).

2. The stiffness-reduced and damping-enhanced squeeze film damper according to claim 1, characterized in that: The boss (10) is fixedly connected to the inner wall of the annular groove (9).

3. The stiffness-reduced and damping-enhanced squeeze film damper according to claim 1, characterized in that: The protrusion height of the boss (10) is 0.01 mm-0.1 mm.

4. The stiffness-reduced and damping-enhanced squeeze film damper according to claim 1, characterized in that: The boss (10) forms a gap of 0.01 mm to 0.1 mm between the sealing expansion ring (3) and the annular groove (9).

5. The stiffness-reduced and damping-enhanced squeeze film damper according to claim 1, characterized in that: The leakage groove (11) is provided on the outer ring of the sealing expansion ring (3).

6. The stiffness-reduced and damping-enhanced squeeze film damper according to claim 1, characterized in that: The leakage groove (11) is in the shape of an elongated strip and extends circumferentially along the sealing expansion ring (3).

7. The stiffness-reduced and damping-enhanced squeeze film damper according to claim 1, characterized in that: The inner ring of the damper outer ring (1) is provided with an oil supply groove (7) located between the two sealing expansion rings (3), and the oil supply hole (6) is communicated with the oil supply groove (7).

8. The stiffness-reduced and damping-enhanced squeeze film damper according to claim 1, characterized in that: A first sealing surface (12) is formed between the outer ring of the sealing expansion ring (3) and the inner ring of the damper outer ring (1).

9. The stiffness-reduced and damping-enhanced squeeze film damper according to claim 1, characterized in that: The cross section of the sealing expansion ring (3) is rectangular.

10. The stiffness-reduced and damping-enhanced squeeze film damper according to claim 1, characterized in that: A butt-jointing notch is provided on the sealing expansion ring (3), and the sealing expansion ring (3) fits with the inner ring of the damper outer ring (1) through its own elastic force.

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