Combined seal squeeze film damper

Abstract

The application discloses a combined sealing type extrusion oil film damper, which comprises a damper inner ring and a damper outer ring and an oil film formed between the two rings, two annular mounting ring grooves are arranged between the damper inner ring and the damper outer ring, the two mounting ring grooves are located at the axial two ends of the oil film, and each of the two mounting ring grooves is provided with a set of annular combined sealings for sealing the axial two ends of the oil film. Each combined sealing comprises an expansion ring located at the inner side and in the form of a notched annulus and a rubber ring located at the outer side and in the form of an annulus, the combined sealing is abutted against the inner annular surface of the damper outer ring through the outer annular surface of the rubber ring to form a first sealing surface, and is abutted against the side wall surface of the mounting ring groove through the side end surface of the combined sealing to form a second sealing surface. The damper fully utilizes the good sealing performance of the rubber ring and the working characteristics of the expansion ring, realizes good sealing performance, and can not additionally increase the nonlinear stiffness and damping due to the increase of the sealing structure.

Description

Technical Field

[0001] This invention relates to the field of damper technology, and in particular, to a combined sealed extrusion oil film damper. Background Technology

[0002] Squeeze film dampers (SFDs) are often used at the support positions of rotor systems to reduce rotor amplitude. However, as rotors continue to develop towards higher speeds and higher operating conditions, rotor systems place higher demands on the vibration reduction performance of SFDs. To meet this requirement, end sealing devices are added to both ends of the SFD. Sealing expansion rings and O-rings are commonly used end sealing devices.

[0003] The sealing expansion ring has a slit and is elastic. In its free state, it is not perfectly round, but after being installed inside the ring groove, it is compressed by the outer ring of the SFD (Self-Dip Fiber) ring, at which point it becomes perfectly round. After installation, the outer circumference of the sealing expansion ring adheres tightly to the outer ring of the SFD ring due to its own elasticity, forming the first sealing surface to prevent oil leakage. Under oil pressure, the expansion ring is pushed to the outside of the ring groove and adheres tightly to the side wall of the ring groove, forming the second sealing surface to prevent oil leakage. The installation diagrams of each expansion ring and each sealing surface are shown below. Figure 1 As shown. During operation, under the action of the two sealing surfaces, the lubricating oil mainly flows out through the expansion ring notch and the oil leakage hole, and the outside air also mainly enters the SFD through the expansion ring notch and the oil leakage hole. The fluid outflow or inflow channels are significantly reduced compared to the open SFD of the end-sealed component, thereby reducing the axial flow of lubricating oil, allowing the lubricating oil to be fully squeezed, and also effectively reducing air intake and improving the integrity of the oil film.

[0004] A simplified structural diagram of the O-ring type extrusion oil film damper is shown below. Figure 2 As shown in the figure, d represents the diameter of the O-ring in its natural state. After the O-ring is installed in the sealing grooves on both sides of the SFD, it will generally undergo tensile deformation, with a certain amount of stretching. The O-ring is placed laterally in the grooves on both sides of the oil film axially. In the figure, c0 represents the size of the groove, which is slightly larger than the oil film gap c of the SFD. The material of the O-ring is generally rubber, unlike metal materials. Rubber materials usually have better recovery characteristics, so even if there are processing errors and assembly errors during the processing and installation of the damper, the O-ring can still completely seal the lubricating oil.

[0005] When the end sealing device is a sealing expansion ring and an O-ring, the following disadvantages exist: 1. In the design of sealing expansion rings, to simplify the design process, the oil film pressure is often assumed to be a constant value. However, in actual dampers, the oil film pressure exhibits a certain periodicity, that is, the oil film pressure changes from positive pressure to negative pressure and back to positive pressure, with a pressure variation range of up to more than ten atmospheres. Furthermore, during operation, the expansion ring experiences periodic vibration due to the continuous friction between the second sealing surface and the expansion ring. Under the combined effect of the constantly changing oil film pressure and periodic vibration, the axial position of the expansion ring in the annular groove has a certain degree of uncertainty. Once the expansion ring undergoes axial movement, the second sealing surface will fail, allowing lubricating oil to bypass the expansion ring and flow out from the original second sealing surface. Additionally, outside air can also bypass the expansion ring and flow into the SFD (Self-Damping Device), significantly reducing the sealing performance of the expansion ring and consequently reducing the vibration damping performance of the oil film. A schematic diagram of the axial position of the expansion ring in the annular groove after axial movement is shown below. Figure 3 As shown; 2. Theoretically, the outer surface of the sealing expansion rings installed at both ends of the extrusion film damper should be able to tightly adhere to the outer ring of the damper to form the first sealing surface. However, due to machining and assembly errors, it cannot be guaranteed that the outer surface of the expansion ring will completely fit with the inner surface of the outer ring of the damper after installation in the ring groove. In fact, the expansion ring may even be compressed into an ellipse after installation in the ring groove. In this state, partial sealing gaps will be generated, thus reducing the sealing effect of the expansion ring. A schematic diagram of the sealing between the expansion ring and the outer ring of the damper when the expansion ring is not completely sealed is shown below. Figure 4 As shown; 3. In the working state, the inner ring of the damper in an aero-engine is in an oscillating state. This oscillation causes a change in the relative position between the expansion ring and the outer ring of the damper. Traditional expansion rings have a rectangular cross-section, which cannot accommodate this change in position and is therefore further compressed. This further compression prevents the outer surface of the expansion ring from tightly adhering to the outer ring of the damper, creating new leakage channels and reducing the sealing performance of the expansion ring. 4. When designing the sealing expansion ring, the thermal expansion of the expansion ring material must be considered. Therefore, the design value of the notch gap of the expansion ring is usually greater than the thermal expansion amount of the expansion ring. This results in the expansion ring not being able to completely seal the circumferential flow channel of the SFD, and lubricating oil can flow out from the notch of the expansion ring; 5. O-rings are generally made of rubber, exhibiting nonlinear stiffness and nonlinear damping. When the damper operates under different conditions, the damping and stiffness of the O-ring will change accordingly. There is a strong nonlinear relationship between the stiffness and damping of the O-ring and the journal's motion frequency and eccentricity. When the damper end-sealing device is an O-ring, the nonlinear stiffness and damping of the O-ring itself make it difficult to control the overall stiffness and damping of the O-ring-extrusion film damper system. Summary of the Invention

[0006] This invention provides a combined sealed extrusion oil film damper to solve the technical problems of poor sealing performance, poor sealing structure stability, and difficulty in controlling the overall stiffness and damping of the system when using existing single sealing rings and expansion rings.

[0007] The technical solution adopted in this invention is as follows: A combined sealed extrusion oil film damper includes: an inner damper ring and an outer damper ring fitted together, and an oil film formed between the inner and outer damper rings. Two annular mounting grooves are also provided between the inner and outer damper rings, located at both axial ends of the oil film. Each mounting groove contains a set of annular combined seals to seal both axial ends of the oil film. Each combined seal includes an inner, notched annular expansion ring and an outer, annular rubber ring. The combined seal presses against the inner annular surface of the outer damper ring through the outer annular surface of the rubber ring to form a first sealing surface, and presses against the side wall surface of the mounting groove through the side end face of the combined seal to form a second sealing surface.

[0008] Furthermore, the axial ring height L of the expansion ring is 0.05mm to 0.15mm less than the width of the corresponding mounting ring groove; the radial thickness B of the expansion ring is designed according to its ring height L so that the combined seal meets the motion control equation, thereby preventing the combined seal from rotating under force during operation.

[0009] Furthermore, to prevent the combined seal from rotating during operation, the frictional force of its first sealing surface must be greater than that of its second sealing surface, thus yielding the motion control equation: Among them, F T F is the elastic force generated by the compression of the expansion ring. J R1 represents the equivalent force of the oil film on the first sealing surface; f1 and f2 represent the friction coefficients of the first and second sealing surfaces, respectively; Δp represents the dynamic oil film pressure generated during the operation of the extrusion oil film damper; R1 is the inner ring radius of the combined seal; R2 is the inner ring radius of the oil film; and R3 is the outer ring radius of the oil film.

[0010] Furthermore, the formula for the elastic force FT generated by the compression of the expansion ring is: Where E is the elastic modulus of the expansion ring material; Δh is the amount of compression of the expansion ring notch; L is the ring height of the expansion ring; and B is the radial thickness of the expansion ring.

[0011] Furthermore, the dynamic oil film pressure Δp generated during the operation of the squeeze oil film damper can be obtained through two methods: one is direct numerical solution using computational fluid dynamics; the other is analytical solution based on the long bearing assumption and a simplified Reynolds equation, the theoretical expression of which is: Where μ is the viscosity of the lubricating oil; R is the inner radius of the extrusion film damper; C is the oil film gap of the extrusion film damper; Ω represents the operating speed of the extrusion film damper; ε is the eccentricity of the extrusion film damper during operation; and θ represents the circumferential angle starting from the position of the maximum oil film.

[0012] Furthermore, the width of the rubber ring is less than the height L of the expansion ring; the radial thickness of the rubber ring must ensure that the radial clearance between the inner ring and the bottom surface of the mounting ring groove is 2 to 3 times the thickness of the oil film when the combined sealing component is used.

[0013] Furthermore, to control the radial clearance, the actual deformation of the rubber ring needs to be numerically simulated, including the following steps: performing a uniaxial tensile test on the rubber material of the rubber ring; fitting a hyperelastic constitutive model based on the stress-strain data obtained from the uniaxial tensile test to determine the material constants C1 and C2 of the expansion ring; assigning the material constants C1 and C2 to the model, and then applying the elastic force F generated by the compression of the expansion ring. T The equivalent force F of the oil film force on the first sealing surface J The radial load was synthesized, and constraint boundary conditions were set; the actual deformation of the rubber ring was calculated.

[0014] Furthermore, the inner ring surface of the damper outer ring is recessed to form an oil supply groove, and an oil supply hole communicating with the oil supply groove is also machined on the damper outer ring to introduce external lubricating oil into the oil supply groove and thus form an oil film between the damper inner ring and the damper outer ring; the mounting ring groove is formed by recessing the outer ring surface of the damper inner ring; the combined seal also includes end face rubber embedded in the expansion ring notch; the combined sealed extrusion oil film damper also includes a support bearing installed in the damper inner ring and a rotating shaft supported in the support bearing.

[0015] Furthermore, the rubber ring and the expansion ring are connected by vulcanization bonding; each of the two end faces of the expansion ring notch is connected by a piece of end face rubber by vulcanization bonding, and the end face rubber is also connected to the corresponding rubber ring by vulcanization bonding.

[0016] Furthermore, the rubber ring and the expansion ring are connected by a tongue and groove structure, and at least one of the two end faces of the expansion ring notch is fitted with end face rubber, and the end face rubber is integrally formed with the rubber ring; or, the rubber ring, the expansion ring and the end face rubber are integrally formed by insert injection molding process.

[0017] The present invention has the following beneficial effects: In the combined sealed extrusion oil film damper of this invention, the outer ring of the combined seal is a rubber ring. Due to the characteristics of the rubber material itself, the coefficient of friction between the rubber and the outer ring of the damper is greater than that between the metal expansion ring and the outer ring of the damper. Therefore, compared with the traditional metal expansion ring sealed extrusion oil film damper, the O-ring expansion ring-rubber ring combined seal of this invention has greater friction with the outer ring of the damper, thus it is less prone to axial movement and rotation with the shaft in the mounting ring groove during operation, resulting in higher stability. After the expansion ring-rubber ring combined seal of this invention is installed in the mounting ring groove, the rubber ring has good elasticity and resilience, and can fully and tightly adhere to the groove under the action of the expansion ring's elastic force. The outer ring of the damper provides superior sealing performance compared to traditional metal expansion rings, making it less prone to failure of the first and second sealing surfaces, which could lead to oil leakage and external air ingress. The expansion ring-rubber ring combined seal of this invention has higher stability, so the combined seal only contacts the outer ring of the damper and is less likely to contact the inner ring, thus reducing the factors affecting the overall system damping and stiffness. This is beneficial for controlling the damping and stiffness of the overall extrusion oil film damper. Therefore, this invention's combined sealing extrusion oil film damper fully utilizes the good sealing performance of the rubber ring and combines it with the working characteristics of the expansion ring to achieve excellent sealing performance without adding extra nonlinear stiffness and damping due to the increased sealing structure, making it suitable for vibration reduction design in aero-engines.

[0018] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the existing expansion ring installation; Figure 2 This is a simplified structural diagram of an O-ring type extrusion oil film damper; Figure 3 This is a schematic diagram showing the axial position of the expansion ring within the annular groove; Figure 4 This is a schematic diagram of the seal between the expansion ring and the outer ring of the damper when the expansion ring is not completely sealed. Figure 5 This is a cross-sectional front view schematic diagram of a preferred embodiment of the combined sealed extrusion oil film damper of the present invention; Figure 6 yes Figure 5 Schematic diagram of the spatial structure of the combined seal; Figure 7 yes Figure 5 Enlarged schematic diagram of a portion of the combined sealing element; Figure 8 yes Figure 5 Diagram showing the failure state of the second sealing surface due to deformation of the middle rubber ring; Figure 9 yes Figure 5 Schematic diagram showing the relationship between the thickness of the middle rubber ring and the height of the expansion ring; Figure 10 This is a schematic diagram of the rubber at the notch end of the expansion ring; Figure 11 This is a schematic diagram of the end of the assembled seal in a free state during vulcanization bonding; Figure 12 This is a schematic diagram of the end of the combined seal in the working state during vulcanization bonding; Figure 13 This is a schematic diagram of a mortise and tenon joint structure; Figure 14 This is a schematic diagram of the end of the combined seal in a free state during the tenon-and-groove connection. Figure 15 This is a schematic diagram of the end of the combined seal in the working state when the tenon and groove connection is in operation.

[0020] Legend: 1. Damper outer ring; 101. Oil supply hole; 102. Oil supply groove; 2. Inner ring of the damper; 3. Combined seals; 31. Rubber ring; 32. Expansion ring; 33. End face rubber; 4. Support bearing; 5. Rotating shaft; 8. Oil film. Detailed Implementation

[0021] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0022] Those skilled in the art will understand that, unless specifically stated otherwise, the term "comprising" as used in this specification means the presence of the stated features, integers, steps, operations, components, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, components, and / or combinations thereof. It should be understood that when we say a component is "connected" to another component, it can be directly connected to the other component or connected via an intermediate component. The term "and / or" as used herein includes all or any unit and all combinations of one or more associated listed items. The terms "first" and "second," etc., in this specification and claims are used to distinguish different objects, not to describe a particular order.

[0023] Reference Figure 5 and Figure 6 A preferred embodiment of the present invention provides a combined sealed extrusion oil film damper, comprising: an inner damper ring 2 and an outer damper ring 1 disposed in an inner and outer sleeve, and an oil film 8 formed between the inner damper ring 2 and the outer damper ring 1. Two annular mounting grooves are also provided between the inner damper ring 2 and the outer damper ring 1, located at both axial ends of the oil film 8. Each of the two mounting grooves contains a set of annular combined seals 3 to seal both axial ends of the oil film 8. Each combined seal 3 includes an inner notched annular expansion ring 32 and an outer annular rubber ring 31. The combined seal 3 presses against the inner annular surface of the outer damper ring 1 through the outer annular surface of the rubber ring 31 to form a first sealing surface, and presses against the side wall surface of the mounting groove through the side end face of the combined seal 3 to form a second sealing surface.

[0024] In the combined sealed extrusion oil film damper of the present invention, the outer ring of the combined seal 3 is a rubber ring 31. Due to the characteristics of the rubber material of the rubber ring 31, the friction coefficient between the rubber and the outer ring 1 of the damper is greater than that between the metal expansion ring and the outer ring 1 of the damper. Therefore, compared with the traditional metal expansion ring sealed extrusion oil film damper, the O-ring expansion ring-rubber ring combined seal 3 of the present invention has a greater friction force with the outer ring 1 of the damper, and is therefore less prone to axial movement and rotation with the shaft in the mounting ring groove during operation, thus having higher stability. After the expansion ring-rubber ring combined seal 3 of the present invention is installed in the mounting ring groove, due to the good elasticity and recovery of the rubber ring 31, it can fully recover under the action of the elastic force of the expansion ring 32. The sealing surface is tightly attached to the outer ring 1 of the damper, thus achieving a sealing performance superior to that of traditional metal expansion rings. This prevents the first and second sealing surfaces from failing, which could lead to oil leakage and the ingress of external air. The expansion ring-rubber ring type combined seal 3 of this invention has higher stability, so it only contacts the outer ring 1 of the damper and is less likely to contact the inner ring 2. This reduces the factors affecting the overall damping and stiffness of the system, and is beneficial for controlling the damping and stiffness of the overall extrusion oil film damper. Therefore, this invention's combined sealing extrusion oil film damper fully utilizes the good sealing performance of the rubber ring 31 and combines it with the working characteristics of the expansion ring 32 to achieve excellent sealing performance. Furthermore, it does not require additional nonlinear stiffness or damping due to the addition of a sealing structure, making it suitable for vibration reduction design in aero-engines.

[0025] Optionally, such as Figure 5 As shown, the inner ring surface of the damper outer ring 1 is recessed to form an oil supply groove 102. The damper outer ring 1 also has an oil supply hole 101 connected to the oil supply groove 102, used to introduce external lubricating oil into the oil supply groove 102, thereby forming an oil film 8 between the damper inner ring 2 and the damper outer ring 1. The mounting ring groove is formed by recessing the outer ring surface of the damper inner ring 2. The combined sealed extrusion oil film damper also includes a support bearing 4 installed within the damper inner ring 2, and a rotating shaft 5 supported within the support bearing 4.

[0026] Optionally, such as Figure 7As shown, the axial ring height L of the expansion ring 32 is 0.05mm to 0.15mm less than the width of the corresponding mounting ring groove, in order to reserve space for thermal expansion caused by the temperature rise of the combined seal 3 during operation. If the amount of thermal expansion can be accurately predicted, the gap between the ring height of the expansion ring 32 and the width of the mounting ring groove should be minimized. In this case, the larger the ring height L, the better the sealing performance and structural stability of the combined seal 3. The radial thickness B of the expansion ring 32 is designed according to its ring height L so that the combined seal 3 satisfies the motion control equation, thereby preventing the combined seal 3 from rotating under force during operation. That is, the radial thickness design of the expansion ring 32 needs to take into account its ring height. When the ring height L is determined, the structural parameters of the expansion ring 32 can be made to satisfy the motion control equation by adjusting the radial thickness B, thereby achieving anti-rotation and anti-failure design.

[0027] In this optional solution, such as Figure 7 As shown, to prevent the combined seal 3 from rotating during operation, the friction force of its first sealing surface must be greater than that of its second sealing surface. Therefore, the motion control equation is obtained: ; Among them, F T F represents the elastic force generated by the compression of the expansion ring 32. J The force of the oil film 8 is the equivalent force on the first sealing surface. f1 and f2 represent the friction coefficients of the first and second sealing surfaces, respectively. Δp is the dynamic oil film pressure generated during the operation of the oil film 8 damper. R1 is the inner radius of the combined seal 3. R2 is the inner radius of the oil film 8. R3 is the outer radius of the oil film 8.

[0028] As can be seen from the above formula, the elastic force F generated by the compression of the expansion ring 32 is... T One of the factors affecting the motion control equations is as follows: The formula for expressing the elastic force FT generated by the compression of the expansion ring 32 is: ; Where E is the elastic modulus of the material of expansion ring 32. Δh is the amount of compression of the notch in expansion ring 32. L is the ring height of expansion ring 32. B is the radial thickness of expansion ring 32.

[0029] Therefore, it is necessary to control the elastic force F generated by the compression of the expansion ring 32 through the adaptive design of L and B. T This satisfies the aforementioned motion control equations, effectively preventing the combined seal 3 from failing due to rotation under stress during operation.

[0030] In this optional scheme, the dynamic oil film pressure Δp generated during the operation of the squeeze oil film 8 damper can be obtained through two methods: First, by directly solving the problem numerically using computational fluid dynamics (CFD) methods. Second, by simplifying the Reynolds equation based on the long bearing assumption and then solving it analytically, the theoretical expression of which is: ; Where μ is the viscosity of the lubricating oil. R is the inner radius of the extrusion oil film damper 8. C is the oil film clearance of the extrusion oil film damper 8. Ω represents the operating speed of the extrusion oil film damper 8. ε is the eccentricity of the extrusion oil film damper 8 during operation. θ represents the circumferential angle starting from the position of maximum oil film.

[0031] Optionally, after the expansion ring-rubber ring combination seal 3 is installed inside the mounting ring groove, the rubber ring 31 deforms under external force. When the rubber ring 31 deforms, it may come into contact with the side of the mounting ring groove. If the expansion ring 32 deforms too much, it will separate from the side of the mounting ring groove, causing the second sealing surface to fail. Figure 8 As shown. When the second sealing surface fails, only the contact surface between the rubber ring 31 and the side wall of the mounting ring groove provides a sealing effect. This contact surface area is small; even slight shaking or torsional deformation of the expansion ring-rubber ring combination seal 3 during operation can cause this contact sealing surface to fail, thereby reducing the vibration damping performance of the squeeze oil film damper. To avoid this situation, the width of the rubber ring 31 (in the direction of the ring height L of the expansion ring 32) needs to be designed to be slightly smaller than the ring height L of the expansion ring 32. Figure 9 As shown, the width of the deformed rubber ring 31 is less than the ring height of the expansion ring 32, and the closer the deformed width is to and not greater than the ring height of the expansion ring 32, the better the sealing effect.

[0032] Optionally, the selection of the radial thickness of the rubber ring 31 should take into account factors such as the radial elastic force of the expansion ring, the equivalent oil film pressure, the deformation of the rubber ring, and the radial clearance at the bottom of the expansion ring, so as to ensure that during operation, the radial thickness of the rubber ring 31 is sufficient to ensure that the radial clearance between the inner ring and the bottom surface of the mounting ring groove of the combined sealing component 3 is 2 to 3 times the thickness of the oil film 8.

[0033] In this optional solution, the deformation of the rubber ring 31 needs to be estimated in order to predict and control this gap. The rubber ring mainly bears two types of forces: one is the elastic force F generated by the compression of the expansion ring 32. T Secondly, the equivalent force F of the oil film force on the first sealing surface. J Under the combined action of these two forces, the rubber ring will undergo corresponding radial deformation. The deformation of the rubber ring 31 can be determined through numerical simulation, including the following steps: A uniaxial tensile test was performed on the rubber material of rubber ring 31; Based on the stress-strain data obtained from the uniaxial tensile test, a hyperelastic constitutive model was fitted to determine the material constant C1 of the expansion ring 32 and the material constant C2 of the rubber ring 31. After assigning material constants C1 and C2 to the model, the elastic force F generated by the compression of the expansion ring 32 is applied. T The equivalent force F of the oil film on the first sealing surface J The synthesized radial load is then applied, and constraint boundary conditions are set. The actual deformation of rubber ring 31 was calculated.

[0034] Specifically, before calculating the actual deformation of the rubber ring 31, it is necessary to obtain the key structural parameters of the combined seal 3, such as the ring height L, radial thickness B, width, and radial thickness of the rubber ring.

[0035] Optionally, such as Figure 6 As shown, the combined seal 3 also includes an end-face rubber 33 embedded in the notch of the expansion ring 32, thereby completely sealing the gap of the notch of the expansion ring 32 and significantly improving the sealing performance of the combined seal 3. At the same time, due to the good elasticity of rubber, the end-face rubber 33 will not affect the thermal expansion of the metal expansion ring if the design is reasonable.

[0036] In this optional solution, the rubber ring 31 and the expansion ring 32 are connected by vulcanization bonding; each of the two end faces of the notch of the expansion ring 32 is connected by vulcanization bonding to an end face rubber 33, and the end face rubber 33 is also connected to the corresponding rubber ring 31 by vulcanization bonding. Specifically, the interaction between the metal and non-metal surfaces through vulcanization forms a multi-component system. Compared with adhesive bonding, vulcanization bonding has advantages such as strong connection, high temperature resistance, and corrosion resistance; the expansion ring-rubber ring type combined seal 3 also incorporates end face rubber 33 at both ends of the expansion ring notch through a vulcanization bonding process, as shown in the figure. Figure 10 As shown in the diagram. A schematic diagram of the expansion ring-rubber ring type combined seal 3 in its free and working states is shown below. Figures 11-12 As shown. The end face rubber 33 can completely fill the gap of the expansion ring, so that the end of the expansion ring-rubber ring type combined seal 3 is in a small gap or even zero gap state during operation, thereby significantly improving the sealing performance of the expansion ring-rubber ring type combined seal 3 compared with the traditional expansion ring; in addition, since the end face rubber 33 has good elasticity, it will not affect the thermal expansion of the metal expansion ring. Preferably, the rubber ring 31 is centrally bonded to the outer circumference of the expansion ring 32.

[0037] In this optional solution, the rubber ring 31 and the expansion ring 32 are connected by a mortise and tenon structure. Specifically, the inner surface of the rubber ring 31 is machined with a rubber tenon, while the outer surface of the metal expansion ring 32 is machined with a mortise and tenon that matches the cross-section of the rubber tenon. A detailed structural cross-sectional diagram is shown below. Figure 13As shown. To improve the sealing performance of the new sealing structure, at least one end face rubber 33 needs to be tightly attached to at least one end face of the notch of the expansion ring 32, and the end face rubber 33 and the rubber ring 31 are integrally formed, as shown. Figures 14-15 As shown. Furthermore, the tenon forms are diverse, including but not limited to triangular tenons, dovetail tenons, and fir tree tenons. The end face rubber 33 can completely fill the gap of the expansion ring, thus ensuring that the end of the expansion ring-rubber ring combination seal 3 is in a small gap or even zero gap state during operation. This significantly improves the sealing performance of the expansion ring-rubber ring combination seal 3 compared to the traditional expansion ring 32. In addition, because the end face rubber 33 has good elasticity, it does not affect the thermal expansion of the metal expansion ring.

[0038] In this optional solution, the rubber ring 31, the expansion ring 32, and the end face rubber 33 are integrally molded using an insert injection molding process. Specifically, the expansion ring 32 is placed as an insert in a mold, and moldable rubber ring material is injected. After cooling, an integral sealing ring is formed on its surface. When using this process, the material must be thermoplastic rubber, and its maximum continuous operating temperature must be significantly higher than the expected operating temperature of the extruded oil film damper system.

[0039] When the expansion ring-rubber ring combination seal 3 is in a free state, its overall shape is not perfectly round. After the combination seal 3 is installed into the mounting ring groove, it is compressed, thus compressing it into a perfect circle. When the metal expansion ring 32 is compressed, the elastic force generated by the expansion ring acts on the rubber ring 31. Due to the good elasticity and recovery characteristics of the rubber ring 31, under the pressure of the expansion ring 32, the rubber ring 31 can fully adhere to the outer ring 1 of the damper, thereby achieving a good sealing effect.

[0040] When the end sealing device of the squeeze film damper is a metal expansion ring, the coefficient of friction between the expansion ring and the outer ring 1 of the damper is relatively small, and the expansion ring is prone to rotation and axial movement during operation. However, when the end sealing device is an expansion ring-rubber ring combination seal 3, the friction between the combination seal 3 and the outer ring 1 of the damper is between metal and rubber, and its coefficient of friction is higher than that between metals. This indicates that the combination seal 3 is less prone to rotation and axial movement during use.

[0041] When the end seal of the extrusion film damper is an O-ring, the O-ring is in direct contact with the outer ring 1 and inner ring 2 of the damper. This alters the working conditions of the journal movement (journal precession frequency and dynamic eccentricity), causing a change in the stress state of the O-ring. Consequently, the stiffness and damping of the O-ring change nonlinearly, making it difficult to control the overall mechanical performance of the extrusion film damper. However, when the extrusion film damper uses a combined seal 3, the combined seal 3 only contacts the outer ring 1 of the damper. Therefore, changes in the mechanical parameters of the combined seal 3 itself do not affect the overall mechanical performance of the extrusion film damper.

[0042] Compared to traditional metal expansion rings, the expansion ring-rubber ring combination seal 3 requires more design considerations, primarily in terms of the friction on the first sealing surface. The friction on the first sealing surface of the expansion ring-rubber ring combination seal 3 cannot be too high or too low. If the friction is too high, the lubricating oil pressure cannot push the combination seal 3 against the side wall of the mounting ring groove, thus failing to form the second sealing surface; if the friction is too low, the combination seal 3 is prone to rotation during operation, leading to accelerated wear and shortened service life. The friction on the first sealing surface of the expansion ring-rubber ring combination seal 3 is affected by the coefficient of friction between rubber and metal, but this coefficient is related to the hardness of the rubber. Rubber hardness is not a constant value and is closely related to the stress state of the rubber. Therefore, when designing the expansion ring-rubber ring combination seal 3, it is necessary to comprehensively consider the pressure level of the extrusion oil film damper and the hardness variation of the rubber.

[0043] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., 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 combined sealed extrusion oil film damper, characterized in that, include: The inner ring (2) and outer ring (1) of the damper are fitted together, and an oil film (8) is formed between the inner ring (2) and outer ring (1). Two annular mounting grooves are also provided between the inner ring (2) and outer ring (1). The two mounting grooves are located at both ends of the oil film (8). Each of the two mounting grooves is provided with a set of annular combined seals (3) to seal both ends of the oil film (8). Each combined seal (3) includes an expansion ring (32) located on the inner side and in the shape of a notched ring, and a rubber ring (31) located on the outer side and in the shape of a ring. The combined seal (3) presses against the inner ring surface of the damper outer ring (1) through the outer ring surface of the rubber ring (31) to form a first sealing surface, and presses against the side wall surface of the mounting ring groove through the side end face of the combined seal (3) to form a second sealing surface.

2. The combined sealed extrusion oil film damper according to claim 1, characterized in that, The axial ring height L of the expansion ring (32) is 0.05mm to 0.15mm less than the width of the corresponding mounting ring groove; The radial thickness B of the expansion ring (32) is adapted to its ring height L so that the combined seal (3) satisfies the motion control equation, thereby preventing the combined seal (3) from rotating under force during operation.

3. The combined sealed extrusion oil film damper according to claim 2, characterized in that, To prevent the combined seal (3) from rotating during operation, the friction force of its first sealing surface must be greater than that of its second sealing surface. Therefore, the motion control equation is obtained: ； Among them, F T F is the elastic force generated by the compression of the expansion ring (32); J The force of the oil film (8) is the equivalent force on the first sealing surface; f1 and f2 represent the friction coefficients of the first sealing surface and the second sealing surface, respectively; Δp is the dynamic oil film (8) pressure generated during the operation of the oil film (8) damper; R1 is the inner circle radius of the combined seal (3); R2 is the inner circle radius of the oil film (8); R3 is the outer circle radius of the oil film (8).

4. The combined sealed extrusion oil film damper according to claim 3, characterized in that, The elastic force F generated by the compression of the expansion ring (32) T The formula for expressing it is: ； Where E is the elastic modulus of the expansion ring (32) material; Δh is the amount of compression of the notch in the expansion ring (32); L is the ring height of the expansion ring (32); and B is the radial thickness of the expansion ring (32).

5. The combined sealed extrusion oil film damper according to claim 3, characterized in that, The dynamic oil film (8) pressure Δp generated during the operation of the damper can be obtained in two ways: one is by direct numerical solution using computational fluid dynamics (CFD); the other is by analytical solution of the Reynolds equation after simplification based on the long bearing assumption, and its theoretical expression is: ； Where μ is the viscosity of the lubricating oil; R is the inner radius of the squeeze oil film (8) damper; C is the gap of the oil film (8) damper; Ω represents the working speed of the squeeze oil film (8) damper; ε is the eccentricity of the squeeze oil film (8) damper during operation; and θ represents the circumferential angle starting from the position of the maximum oil film.

6. The combined sealed extrusion oil film damper according to claim 2, characterized in that, The width of the rubber ring (31) is less than the ring height L of the expansion ring (32); The radial thickness of the rubber ring (31) must ensure that the radial gap between its inner ring and the bottom surface of the mounting ring groove is 2 to 3 times the thickness of the oil film (8) when the combined seal (3) workpiece is used.

7. The combined sealed extrusion oil film damper according to claim 6, characterized in that, To control the radial clearance, the actual deformation of the rubber ring (31) needs to be obtained through numerical simulation, including the following steps: A uniaxial tensile test was performed on the rubber material of the rubber ring (31); Based on the stress-strain data obtained from the uniaxial tensile test, a hyperelastic constitutive model was fitted to determine the material constant C1 of the expansion ring (32) and the material constant C2 of the rubber ring (31); After assigning material constants C1 and C2 to the model, the elastic force F generated by the compression of the expansion ring (32) is applied. T The equivalent force F of the oil film (8) on the first sealing surface J The synthesized radial load is then applied, and constraint boundary conditions are set. The actual deformation of the rubber ring (31) was calculated.

8. The combined sealed extrusion oil film damper according to claim 1, characterized in that, The inner ring surface of the outer ring (1) of the damper is recessed to form an oil supply groove (102). The outer ring (1) of the damper is also machined with an oil supply hole (101) that connects to the oil supply groove (102) to introduce external lubricating oil into the oil supply groove (102) and thus form an oil film (8) between the inner ring (2) and the outer ring (1) of the damper. The mounting groove is formed by recessing the outer ring surface of the inner ring (2) of the damper; The combined seal (3) also includes end face rubber (33) embedded in the notch of the expansion ring (32); The combined sealed extrusion oil film damper also includes a support bearing (4) installed in the inner ring (2) of the damper, and a rotating shaft (5) supported in the support bearing (4).

9. The combined sealed extrusion oil film damper according to claim 8, characterized in that, The rubber ring (31) and the expansion ring (32) are connected by vulcanization bonding; Each of the two end faces of the notch of the expansion ring (32) is connected to an end face rubber (33) by vulcanization bonding, and the end face rubber (33) is also connected to the corresponding rubber ring (31) by vulcanization bonding.

10. The combined sealed extrusion oil film damper according to claim 8, characterized in that, The rubber ring (31) and the expansion ring (32) are connected by a tenon and mortise structure. At least one end face of the notch of the expansion ring (32) is fitted with end face rubber (33), and the end face rubber (33) is integrally formed with the rubber ring (31); or The rubber ring (31), the expansion ring (32), and the end face rubber (33) are integrally formed by insert injection molding process.

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