An extrusion oil film damper capable of actively coarsely and finely adjusting the oil film clearance

Abstract

The present invention discloses an squeeze film damper capable of actively coarsely and finely adjusting the oil film clearance, belonging to the technical field of squeeze film dampers; it includes a bearing installation sleeve with a flange at one end, and an outer conical axial displacement ring, a damper oil film inner ring and a damper oil film outer ring are successively sleeved on the outer wall of the bearing installation sleeve far from the flange end in concentric circles from inside to outside; a sealed oil film cavity is formed between the outer walls of the damper oil film outer ring and the damper oil film inner ring, and the damper oil film inner ring is slidably connected with the outer conical axial displacement ring through a conical contact surface arranged between the two, and a piezoelectric ceramic stack, a screw axial displacement ring and a coarse adjustment hexagonal screw are successively arranged between the large end surface side of the outer conical axial displacement ring and the flange of the bearing installation sleeve. The device of the present invention can eliminate the influence of installation errors on the oil film clearance, quickly and accurately adjust the oil film parameters, and the dynamic adjustment of the oil film parameters under different working conditions can make the damper work in the linear region.

Description

Technical Field

[0001] The present invention relates to an adjustable squeeze film damper, and more particularly to a squeeze film damper capable of actively coarsely and finely adjusting the oil film gap, belonging to the technical field of squeeze film dampers. Background Art

[0002] The rotor structure of a gas turbine is often relatively complex, and the loads are also diverse. The unbalanced forces generated by factors such as the gravity of the rotor system, manufacturing and assembly errors, as well as fluid excitation and gap circulation in the seal, often cause strong vibrations of the rotor system. According to statistics, more than 90% of the structural strength failures of aeroengines are directly or indirectly caused by rotor vibrations. In order to reduce the vibrations of the rotor system, a scheme of using a squeeze film damper in the rotor support system to suppress the vibration amplitude of the rotor is widely adopted. The squeeze film damper is widely used in the structure of aeroengines due to its characteristics such as simple structure, light weight, small volume, high reliability, good processing technology, low cost, and significant vibration reduction effect.

[0003] The application of the squeeze film damper reduces the requirements for the balance of the rotor system and alleviates the fatigue of a series of components such as the rotor support system. However, essentially, the squeeze film damper is a non-linear damper, and its equivalent stiffness and equivalent damping in the rotor system are non-linear functions. Its oil film stiffness increases with the increase of the squeezing effect, and the stronger the squeezing effect, the higher the degree of non-linearity. When operating at high speeds and with large balance amounts, phenomena such as "bistable response", "locking", and non-coordinated precession, which seriously affect the working reliability of the rotor, are extremely likely to occur. Moreover, if the parameters are selected improperly, not only can its vibration reduction effect not be exerted, but it will seriously threaten the operation safety of the rotor system.

[0004] At present, in order to avoid a series of problems brought about by the strong non-linear characteristics of squeeze film dampers, many experts and scholars have improved the structural form of traditional squeeze film dampers. For example, in the public literature 1: Zhou Ming. Research on the Vibration Damping Mechanism of Elastic Ring Squeeze Film Damper [J]. Journal of Aerospace Power, 1998(4):403.DOI:10.13224 / j.cnki.jasp.1998.04.012, it is proposed to add an elastic ring in the middle of the squeeze film to separate the oil film, which has a good vibration damping effect on the established rotor system, but has a high dependence on the accuracy of processing and assembly. Public literature 2: Guo Baoting, Ma Yanhong, Zhao Fuan, etc. Experimental Study on Metal Rubber Outer Ring Adaptive Squeeze Film Damper [J]. Journal of Aerospace Power, 2003,18(1):119-123.DOI:10.3969 / j.issn.1000-8055.2003.01.021., uses special materials to manufacture the inner and outer rings of the squeeze film damper. Limited by the manufacturing process, durability and stability of the new materials, the application of this type of squeeze film damper is restricted. And public literature 3: Zhu Changsheng, Wang Xixuan. Experimental Study on the Vibration Damping Characteristics of a New Type of Hybrid Hydrostatic and Hydrodynamic Squeeze Film Damper [J]. Journal of Vibration Engineering, 1995,(3):281-285.DOI:10.16385 / j.cnki.issn.1004-4523.1995.03.015, uses a throttle to supply oil to the oil chamber to achieve a hybrid hydrostatic and hydrodynamic pressure oil film, but it requires a relatively high oil supply pressure, requires an additional oil supply system, has a complex structure, and is difficult to apply in the case of high space restrictions. Some of the above improvements have relatively high process requirements and there is still a certain distance from actual application, while some structures are too complex and materials are not mature, which are restricted by the application scenarios and are not suitable for application in large heavy-duty gas turbine rotor systems such as aero-engines.

[0005] In addition, as in the invention patent with the authorization announcement number CN106907355B and the invention name of an elastic support squeeze film damper, it specifically discloses a conical oil film squeeze film damper with the oil film normal not perpendicular to the rotor axis. The outer ring of the oil film is connected to the housing through a thread, and by rotating the outer ring of the oil film, it can move axially to change the thickness parameter of the conical oil film. However, the length of the thread is much larger than the thickness dimension of the oil film, and it is difficult to precisely control the oil film thickness by rotating the thread for axial displacement. Moreover, the asymmetric conical oil film will bring additional axial vibration and load to the system, making the safety of the rotor system uncertain. And generally, the dynamic characteristics of common squeeze film dampers are fixed without changing external conditions after design and manufacture. In actual use, it often fails to meet the design requirements due to manufacturing and assembly errors. In addition, some experimental studies on rotor systems also need to analyze the influence of damping value changes on the rotor system.

[0006] Therefore, it has certain research and application value to propose a new type of squeeze film damper with variable parameters. Summary of the Invention

[0007] The object of the present invention is to overcome the problem that the rotor operation reliability is unstable under the conditions of high rotational speed and large balance amount existing in the squeeze film damper in the prior art, and to provide a squeeze film damper that can actively coarsely and finely adjust the oil film gap, which can actively coarsely and finely adjust the oil film parameters, is safe and reliable, and has a wide applicability.

[0008] To achieve the above object, the present invention adopts the following technical solutions: A squeeze film damper that can actively coarsely and finely adjust the oil film gap, including a bearing installation sleeve with a flange at one end, and an outer conical axial displacement ring, a damper oil film inner ring, and a damper oil film outer ring are sequentially sleeved on the outer wall of the bearing installation sleeve away from the flange end concentrically from the inside to the outside; a sealed oil film cavity is formed between the outer walls of the damper oil film outer ring and the damper oil film inner ring, and an elastic support rod for providing elastic support for the damper oil film inner ring is connected between the side end face of the damper oil film outer ring and the flange of the bearing installation sleeve; the damper oil film inner ring is slidably connected to the outer conical axial displacement ring through a conical contact surface provided between the two, the taper of the conical contact surface is 1:10 - 13, and the large end face side of the damper oil film inner ring is located on the bearing installation sleeve away from the flange end, and a positioning end cover for axially contacting and limiting the damper oil film inner ring is fixedly connected to the end face of the bearing installation sleeve away from the flange end; a screw axial displacement ring is arranged between the large end face side of the outer conical axial displacement ring and the flange of the bearing installation sleeve, a piezoelectric ceramic stack is in contact between the two end faces of the outer conical axial displacement ring and the screw axial displacement ring, and a coarse adjustment hexagonal screw is threadedly connected between the screw axial displacement ring and the flange of the bearing installation sleeve.

[0009] The outer diameter of the positioning end cover is smaller than the inner diameter of the damper oil film outer ring, and the inner end of the positioning end cover is fitted and arranged in the annular cavity formed between the damper oil film outer ring and the bearing installation sleeve; a moving gap is arranged between the small end face of the outer conical axial displacement ring and the inner end face of the positioning end cover.

[0010] The piezoelectric ceramic stack is a hollow columnar body, and a plurality of cylindrical bosses are evenly distributed along the circumferential direction on one side end face of the screw axial displacement ring, and the piezoelectric ceramic stack is connected to the cylindrical bosses of the screw axial displacement ring through a central hole.

[0011] A plurality of threaded through holes are evenly distributed along the circumference on the other side end face of the screw axial displacement ring, and the plurality of threaded through holes and the cylindrical bosses are staggered; threaded connection holes are arranged on the inner end face of the flange of the bearing installation sleeve corresponding to the threaded through holes, and the coarse adjustment hexagonal screw is threadedly connected between the threaded through holes and the threaded connection holes.

[0012] The two ends of the coarse adjustment hexagonal screw have opposite thread pitches. The end connected to the screw axial displacement ring has a right-handed thread, and the end connected to the flange of the bearing installation sleeve has a left-handed thread.

[0013] On the outer cylindrical surface of the inner ring of the damper oil film, two grooves are arranged at circumferential intervals. Sealing rings are connected in the two grooves, and a sealed oil film cavity is formed between the outer wall gaps of the outer ring of the damper oil film and the inner ring of the damper oil film through the sealing rings; an oil inlet hole is radially opened on the outer circumference of the outer ring of the damper oil film, and a circumferential oil guiding groove is arranged along the circumference at the connection of the inner wall of the outer ring of the damper oil film and the oil inlet hole. The oil inlet hole is communicated with the oil film cavity through the circumferential oil guiding groove.

[0014] A limiting end face is arranged on the end face of the bearing installation sleeve far from the flange. A sliding bearing and a rotor are arranged inside the limiting end face, and the positioning end cover is fixedly connected to the outside of the limiting end face through screws.

[0015] On the inner side end face of the outer ring of the damper oil film and on the outer circumference of the flange of the bearing installation sleeve, a plurality of threaded holes are evenly distributed along the circumferential direction. One end of the elastic support rod is fixed to the outer ring of the damper oil film through the threaded hole, and the other end is fixed to the flange of the bearing installation sleeve through a connecting nut.

[0016] The beneficial effects of the present invention are as follows:

[0017] 1) The present invention controls the axial displacement of the outer conical axial displacement ring through the hollow columnar piezoelectric ceramic stack and the coarse adjustment hexagonal screw, and further controls the expansion degree of the inner ring of the damper oil film to affect the oil film parameters of the damper, realizing the coarse and fine adjustment effects on the oil film parameters of the damper, thereby realizing the control of the damping characteristics of the squeeze film damper.

[0018] 2) In the device of the present invention, the inclined surface connection between the inner ring of the damper oil film and the outer conical axial displacement ring is used to achieve the purpose of adjusting the axial clearance, that is, the change of the oil film thickness. Moreover, the oil film normal is always perpendicular to the rotor axis, and no additional axial load and vibration will be generated, which can make the device operate more reliably and stably, with high safety performance, and further improve the service life of the bearing.

[0019] 3) In the device of the present invention, the oil film parameters can be quickly changed by turning the coarse adjustment hexagonal screw. By controlling the magnitude and direction of the voltage applied to the piezoelectric ceramic stack, the oil film clearance can be adjusted by several micrometers in a very short time when it is in the working state, which can eliminate the influence of the installation error on the oil film clearance, and the adjustment of the oil film parameters is fast and accurate; the elastic support rod is connected by threads, which is convenient to adjust the number and size of the elastic support rods, thereby changing the support stiffness and critical speed of the system.

[0020] 4) In the device of the present invention, the active adjustment of the oil film gap between the inner and outer rings enables the damper to still meet the working requirements even with certain manufacturing and assembly errors. The dynamic adjustment of the oil film parameters under different working conditions can make the damper operate in the linear region, enabling the rotor system to pass through multiple critical speeds with relatively small vibrations, avoiding the bistable response of the system, and more effectively suppressing the vibration of the rotor. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a structural cross-sectional view of the present invention;

[0022] Figure 2 is a schematic semi-sectional structure diagram of the present invention;

[0023] Figure 3 is Figure 1 a partial enlarged view at A in

[0024] Figure 4 is Figure 1 a schematic structure diagram of the screw axial displacement ring in

[0025] In the figure, 1 - outer ring of the damper oil film, 101 - circumferential oil guide groove, 102 - oil inlet hole, 2 - inner ring of the damper oil film, 3 - outer conical axial displacement ring, 4 - piezoelectric ceramic stack, 5 - elastic support rod, 6 - screw axial displacement ring, 601 - cylindrical boss, 602 - threaded through hole, 7 - coarse adjustment hexagonal screw, 8 - bearing installation sleeve, 9 - axial positioning end cover, 10 - sliding bearing, 11 - screw, 12 - sealing ring, 13 - oil film cavity, 14 - nut. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The present invention will be further explained and illustrated below in conjunction with the drawings and specific embodiments.

[0027] Embodiment: As Figures 1-4As shown in the figure, the present invention provides a squeeze film damper that can actively coarsely and finely adjust the oil film gap, including a bearing installation sleeve 8 with a flange at one end. An outer conical axial displacement ring 3, a damper oil film inner ring 2, and a damper oil film outer ring 1 are successively sleeved on the outer wall of the bearing installation sleeve 8 at the end far from the flange in the same center from inside to outside; a sealed oil film cavity 13 is formed in the gap between the inner wall of the damper oil film outer ring 1 and the outer wall of the damper oil film inner ring 2. An elastic support rod 5 that provides elastic support for the damper oil film inner ring 2 is connected between one end face of the damper oil film outer ring 1 and the flange of the bearing installation sleeve 8; the damper oil film inner ring 2 is slidably connected to the outer conical axial displacement ring 3 through a conical contact surface provided between the two. The taper of the conical contact surface is 1:12.5, and the large end face side of the damper oil film inner ring 2 is located on the bearing installation sleeve 8 at the end far from the flange. A positioning end cover 9 for axially contacting and limiting the damper oil film inner ring 2 is fixedly connected to the end face of the bearing installation sleeve 8 at the end far from the flange; a screw axial displacement ring 6 is arranged between the large end face side of the outer conical axial displacement ring 3 and the flange of the bearing installation sleeve 8. A piezoelectric ceramic stack 4 is arranged in contact between the two end faces of the outer conical axial displacement ring 3 and the screw axial displacement ring 6. The screw axial displacement ring 6 and the flange of the bearing installation sleeve 8 are threadedly connected by a coarse adjustment hexagonal screw 7.

[0028] The outer diameter of the positioning end cover 9 is smaller than the inner diameter of the damper oil film outer ring 1. The inner end of the positioning end cover 9 is fitted and arranged in the annular cavity formed between the damper oil film outer ring 1 and the bearing installation sleeve 8; a moving gap is arranged between the small end face of the outer conical axial displacement ring 3 and the inner end face of the positioning end cover 9.

[0029] The piezoelectric ceramic stack 4 is a hollow cylindrical body. A plurality of cylindrical bosses 601 are evenly distributed along the circumferential direction on one end face of the screw axial displacement ring 6. The piezoelectric ceramic stack 4 is connected to the cylindrical bosses 601 of the screw axial displacement ring 6 through a central hole.

[0030] A plurality of threaded through holes 602 are evenly distributed along the circumference on the other end face of the screw axial displacement ring 6. The plurality of threaded through holes 602 are staggered and distributed between the plurality of cylindrical bosses 601; threaded connection holes are arranged on the inner end face of the flange of the bearing installation sleeve 8 corresponding to the threaded through holes 602. The coarse adjustment hexagonal screw 7 is threadedly connected between the threaded through holes 602 and the threaded connection holes.

[0031] The threads at both ends of the coarse adjustment hexagonal screw 7 are single - thread threads with a pitch of 0.5 mm, and the thread directions at both ends are opposite. The end connected to the screw axial displacement ring 6 is a right - hand thread, and the end connected to the flange of the bearing installation sleeve 8 is a left - hand thread.

[0032] On the outer cylindrical surface of the inner ring 2 of the damper oil film, two grooves are arranged at circumferential intervals. A sealing ring 12 is fitted and connected in the two grooves. A sealed oil film cavity 13 is formed between the outer wall gaps of the outer ring 1 of the damper oil film and the inner ring 2 of the damper oil film through the sealing ring 12; an oil inlet hole 102 is radially opened on the outer circumference of the outer ring 1 of the damper oil film, and a circumferential oil guide groove 101 is arranged along the circumferential direction at the connection with the oil inlet hole 102 on the inner wall of the outer ring 1 of the damper oil film. The oil inlet hole 102 is communicated with the oil film cavity 13 through the circumferential oil guide groove 101.

[0033] A limiting end face is arranged on the end face of the bearing installation sleeve 8 at the end far from the flange. A sliding bearing 10 and a rotor are arranged inside the limiting end face. The positioning end cover 9 is fixedly connected to the outside of the limiting end face through screws 11.

[0034] On the inner side end face of the outer ring 1 of the damper oil film and on the outer circumference of the flange of the bearing installation sleeve 8, a plurality of threaded holes are evenly distributed along the circumferential direction. One end of the elastic support rod 5 is fixed to the outer ring 1 of the damper oil film through the threaded hole, and the other end is fixed to the flange of the bearing installation sleeve 8 through the connecting nut 14.

[0035] Working principle:

[0036] The outer ring 1 of the damper oil film is fixed on the main engine housing. The inner ring 2 of the damper oil film, the outer conical axial displacement ring 3, the bearing installation sleeve 8 and the rolling bearing 10 are successively installed inside the outer ring 1 of the damper oil film. A small gap is left between the outer ring 1 of the damper oil film and the inner ring 2 of the damper oil film and they can move relative to each other radially. Lubricating oil flows from the oil inlet hole 102 through the circumferential oil guide groove 101 into the oil film cavity 13 of the sealed gap to generate an oil film. When the vibration generated by the unbalanced force on the rotor is transmitted to the inner ring 2 of the damper oil film through the rolling bearing 10, the inner ring 2 of the damper oil film undergoes a radial displacement along with the vibration of the rotor, squeezing the oil film to generate a reaction force.

[0037] Between the axial positioning end cover 9 and the flange of the bearing installation sleeve 8, the inner ring 2 of the damper oil film, the outer conical axial displacement ring 3, the hollow cylindrical piezoelectric ceramic stack 4, the screw axial displacement ring 6 and the coarse adjustment hexagonal screw 7 are successively installed and are in contact with each other. A load voltage is connected to the hollow cylindrical piezoelectric ceramic stack 4. By turning the coarse adjustment hexagonal screw 7, it can cause itself and the screw axial displacement ring 6 to generate a large axial movement L, and drive the piezoelectric ceramic stack 4 and the outer conical axial displacement ring 3 to generate an axial displacement L. Due to the axial displacement of the latter, the inner ring 2 of the damper oil film with a conical contact surface and the outer conical axial displacement ring 3 cause a change in the radial dimension of the inner ring 2 of the damper oil film, thereby realizing the coarse adjustment of the oil film thickness; by controlling the magnitude and direction of the piezoelectricity applied to the piezoelectric ceramic stack 4 through the circuit, using its inverse piezoelectric effect to drive the outer conical axial displacement ring 3 to generate a small axial displacement to change the radial dimension of the inner ring 2 of the damper oil film, the fine adjustment of the thickness of the squeezed oil film can be realized.

[0038] In the device of the present invention, the oil film parameters can be quickly changed by turning the coarse adjustment hexagonal screw. By controlling the magnitude and direction of the voltage applied to the piezoelectric ceramic stack, the oil film gap can be adjusted by several micrometers in a very short time when it is in the working state, which can eliminate the influence of installation errors on the oil film gap and adjust the oil film parameters quickly and accurately. The elastic support rods are connected by threads, which is convenient for adjusting the number and size of the elastic support rods, thereby changing the support stiffness and critical speed of the system.

[0039] The above is only used to illustrate the technical solution of the present invention and not to limit it. Other modifications or equivalent replacements made by those of ordinary skill in the art to the technical solution of the present invention should be covered within the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. An extrusion oil film damper capable of actively coarsely and finely adjusting the oil film gap, Characterized in that: It includes a bearing installation sleeve (8) with a flange at one end. An outer conical axial displacement ring (3), a damper oil film inner ring (2), and a damper oil film outer ring (1) are successively sleeved on the outer wall of the bearing installation sleeve (8) concentrically from the inside to the outside at the end far from the flange; A sealed oil film cavity (13) is formed between the outer walls of the damper oil film outer ring (1) and the damper oil film inner ring (2). An elastic support rod (5) for providing elastic support for the damper oil film inner ring (2) is connected between the side end face of the damper oil film outer ring (1) and the flange of the bearing installation sleeve (8); The damper oil film inner ring (2) is slidably connected to the outer conical axial displacement ring (3) through a conical contact surface provided between the two. The taper of the conical contact surface is 1:10 - 13, and the large end face side of the damper oil film inner ring (2) is located on the bearing installation sleeve (8) at the end far from the flange. A positioning end cover (9) for axially contacting and limiting the damper oil film inner ring (2) is fixedly connected to the end face of the bearing installation sleeve (8) at the end far from the flange; A screw axial displacement ring (6) is arranged between the large end face side of the outer conical axial displacement ring (3) and the flange of the bearing installation sleeve (8). A piezoelectric ceramic stack (4) is in contact between the two end faces of the outer conical axial displacement ring (3) and the screw axial displacement ring (6). The screw axial displacement ring (6) and the flange of the bearing installation sleeve (8) are threadedly connected by a coarse - adjustment hexagonal screw (7); The piezoelectric ceramic stack (4) is a hollow columnar body. A plurality of cylindrical bosses (601) are evenly distributed along the circumferential direction on one side end face of the screw axial displacement ring (6). The piezoelectric ceramic stack (4) is connected to the cylindrical bosses (601) of the screw axial displacement ring (6) through a central hole; A plurality of threaded through - holes (602) are evenly distributed along the circumference on the other side end face of the screw axial displacement ring (6). The plurality of threaded through - holes (602) and the cylindrical bosses (601) are staggered. Threaded connection holes are provided on the inner end face of the flange of the bearing installation sleeve (8) corresponding to the threaded through - holes (602). The coarse - adjustment hexagonal screw (7) is threadedly connected between the threaded through - holes (602) and the threaded connection holes.

2. The extrusion oil film damper capable of actively coarsely and finely adjusting the oil film gap according to claim 1, Characterized in that: The outer diameter of the positioning end cover (9) is smaller than the inner diameter of the damper oil film outer ring (1). The inner end of the positioning end cover (9) is fitted and arranged in the annular cavity formed between the damper oil film outer ring (1) and the bearing installation sleeve (8). A moving gap is provided between the small end face of the outer conical axial displacement ring (3) and the inner end face of the positioning end cover (9).

3. The extrusion oil film damper capable of actively coarsely and finely adjusting the oil film gap according to claim 1, Characterized in that: The thread directions at both ends of the coarse - adjustment hexagonal screw (7) are opposite. The end connected to the screw axial displacement ring (6) is a right - hand thread, and the end connected to the flange of the bearing installation sleeve (8) is a left - hand thread.

4. An squeeze film damper capable of actively coarsely and finely adjusting the oil film gap according to claim 1, characterized in that: Two grooves are circumferentially spaced on the outer cylindrical surface of the inner ring (2) of the damper oil film. A sealing ring (12) is fitted and connected in the two grooves. A sealed oil film cavity (13) is formed between the outer wall gaps of the outer ring (1) and the inner ring (2) of the damper oil film through the sealing ring (12); An oil inlet hole (102) is radially opened on the outer circumference of the outer ring (1) of the damper oil film. A circumferential oil guiding groove (101) is arranged circumferentially on the inner wall of the outer ring (1) of the damper oil film at the connection with the oil inlet hole (102). The oil inlet hole (102) is communicated with the oil film cavity (13) through the circumferential oil guiding groove (101).

5. An squeeze film damper capable of actively coarsely and finely adjusting the oil film gap according to claim 1, characterized in that: A limiting end face is arranged on the end face of the bearing installation sleeve (8) at the end far from the flange. A sliding bearing (10) and a rotor are arranged inside the limiting end face. The positioning end cover (9) is fixedly connected to the outside of the limiting end face by screws (11).

6. An squeeze film damper capable of actively coarsely and finely adjusting the oil film gap according to claim 1, characterized in that: A plurality of threaded holes are evenly distributed along the circumferential direction on the inner side end face of the outer ring (1) of the damper oil film and on the outer circumference of the flange of the bearing installation sleeve (8). One end of the elastic support rod (5) is fixed to the outer ring (1) of the damper oil film through a threaded hole, and the other end is fixed to the flange of the bearing installation sleeve (8) through a connecting nut (14).

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