A labyrinth seal type squeeze film damper

Abstract

A labyrinth seal type squeeze film damper of the present invention is sleeved outside a bearing and includes an elastic support. A bearing housing is provided outside the bearing. The head of the elastic support is an inner ring of the damper, and the bearing housing is an outer ring of the damper. A rotor is sleeved inside the bearing. The outer ring of the damper and the inner ring of the damper are in clearance fit, and the clearance is an oil film clearance. An oil supply groove is provided on the outer ring of the damper, and an oil supply hole is opened in the oil supply groove. The oil supply hole is arranged above the oil film clearance. A labyrinth or a groove is circumferentially provided at the end of the outer ring of the damper, and a groove or a labyrinth is circumferentially opened at the end of the inner ring of the damper. A plastic material ring or an easily worn material ring is provided in the groove, and the labyrinth of the damper is arranged corresponding to the material ring of the damper. The damper has a simple structure and good sealing effect. By controlling the specific thickness of the plastic material ring, a linear change in the oil film stiffness of the damper is achieved.

Description

Technical Field:

[0001] The present invention belongs to the technical field of damper design, and particularly relates to a labyrinth seal squeeze film damper. Background Art:

[0002] The rotor system composed of a compressor and a turbine is the core of an aeroengine and plays a crucial role in the engine performance. However, the rotor system has a complex structure, harsh working conditions, and bears various loads. Under such conditions, the vibration problem is very prominent, seriously affecting the engine performance. Therefore, reducing the vibration of the rotor system can greatly improve the engine performance.

[0003] As a structure that can effectively reduce the vibration of the rotor system, the squeeze film damper has been applied to aeroengines for many years. It changes the tight fit between the original bearing housing and the outer ring of the bearing into a clearance fit, and fills the clearance with lubricating oil to form an annular oil film, reducing vibration by squeezing the oil film.

[0004] The basic working principle of the squeeze film damper is that due to the action of unbalanced forces, the rotor squeezes the oil film, and the oil film generates a reaction force, absorbing part of the vibration energy and reducing the vibration transmitted to the support, thereby achieving the vibration reduction effect.

[0005] The squeeze film damper is divided into two types: open type and closed type according to whether there is an oil sealing device at the end.

[0006] The structural schematic diagram of the open type squeeze film damper is as Figure 1 shown. It has a simple structure and reliable operation, and has been widely used in aeroengines. However, the disadvantages of the open type squeeze film damper are also obvious:

[0007] 1) There is no seal at the end of the damper, and the pressures at both ends are the same as the atmospheric pressure, which is less than the squeeze pressure in the middle of the damper. The axial pressure gradient decreases from the middle to both ends, and the lubricating oil at both ends is not fully squeezed, making it difficult for the oil film damping to meet the design requirements;

[0008] 2) The two ends of the open type damper are directly exposed to the atmosphere. The pressure on the side of the oil film squeezed by the journal increases, while the pressure on the other side decreases. When the pressure decreases to less than the atmospheric pressure, air is sucked in due to the pressure difference, reducing the effective squeeze area of the oil film, decreasing the damping, and deteriorating the vibration reduction effect. This phenomenon is almost inevitable and worsens with the increase of the rotor amplitude and speed, resulting in a significant decrease in the oil film damping and even being unable to provide sufficient damping.

[0009] The structural schematic diagram of the closed type squeeze film damper is as Figure 2 shown. Sealing parts such as piston rings are added at both ends, reducing the lubricating oil leakage, increasing the oil film damping, and reducing the air inhalation. Compared with the open type damper, a larger damping can be obtained. However, the closed type damper also has disadvantages:

[0010] 1) The use of seals makes the structure of the closed damper more complex than that of the open damper. The design and manufacturing of the closed damper are difficult, and its working state is not as stable as that of the open damper.

[0011] 2) A section of distance is left at both ends of the closed damper for slotting to assemble the seal. The oil film in this small section cannot be fully squeezed like the middle oil film, and the axial length of the oil film is not fully utilized.

[0012] In summary, adding a sealing structure at both ends of the damper can effectively reduce problems existing in open dampers such as air inhalation. Integrating the sealing structure and the damper and placing them at both ends can increase the stability of the damper and obtain a larger effective extrusion area. At the same time, the sealing structure limits the eccentricity ratio (dynamic eccentricity / oil film clearance) of the damper within 0.4, and the oil film stiffness approximately varies linearly, which is beneficial to the stability of the rotor. Summary of the Invention:

[0013] The object of the present invention is to overcome the deficiencies of the above-mentioned open squeeze film damper and closed squeeze film damper, and propose a squeeze film damper with a labyrinth seal structure added at both ends of the damper. Based on the open squeeze film damper, a ring of labyrinth structure is added at both ends of the outer ring (or inner ring), and a ring of plastic material or easily worn material is correspondingly added to the inner ring (or outer ring) area corresponding to the labyrinth.

[0014] To achieve the above object, the present invention adopts the following technical solutions:

[0015] A labyrinth seal type squeeze film damper is sleeved outside the bearing, including an elastic support. A bearing housing is provided outside the bearing. The head of the elastic support is the inner ring of the damper, and the bearing housing is the outer ring of the damper. A rotor is sleeved inside the bearing. The outer ring and the inner ring of the damper are arranged with a gap, and the gap is the oil film clearance. An oil supply groove is provided on the outer ring of the damper, and an oil supply hole is opened in the oil supply groove. The oil supply hole is arranged above the oil film clearance, where: The labyrinth seal of the damper adopts one of the following methods:

[0016] (1) Labyrinths are circumferentially provided at the end of the outer ring of the damper, grooves are circumferentially opened at the end of the inner ring of the damper, a plastic material ring or an easily worn material ring is provided in the grooves, and the labyrinths at the end of the outer ring of the damper are arranged corresponding to the material ring of the inner ring of the damper;

[0017] (2) Grooves are circumferentially opened at the end of the outer ring of the damper, labyrinths are circumferentially provided at the end of the inner ring of the damper, a plastic material ring or an easily worn material ring is provided in the grooves, and the material ring at the end of the outer ring of the damper is arranged corresponding to the labyrinths of the inner ring of the damper.

[0018] The elastic support member and the rotor are concentrically installed through bearings.

[0019] The lubricating oil is ISO VG2, forming an oil film.

[0020] The depth of the groove formed in the outer or inner ring of the damper corresponds to the thickness of the plastic material ring or the easily worn material ring.

[0021] The bottom of the labyrinth teeth is at the same level as the bottom of the oil film gap, and the top height of the labyrinth teeth is slightly less than the oil film gap.

[0022] The longitudinal thickness of the plastic material ring or the easily worn material ring is reasonably designed according to the maximum unbalanced force received by the engine and is ≤ 0.4 times the oil film gap.

[0023] During the working process of the labyrinth seal type squeeze film damper, the rotor rotates at a high speed, and the labyrinth teeth squeeze the plastic material ring or the easily worn material ring. When it is a plastic material ring, the plastic material ring deforms, and after forming a tooth-shaped groove on the surface of the plastic material ring, a closer fitting relationship is formed with the labyrinth teeth, strengthening the sealing effect. When it is an easily worn material ring, after contact and wear with the labyrinth teeth, a wear groove is left on the ring, strengthening the sealing ability.

[0024] During the working process of the labyrinth seal type squeeze film damper, by controlling the thickness of the plastic material ring or the easily worn material ring ≤ 0.4 times the oil film gap, an eccentricity ≤ 0.4 is achieved, where eccentricity = dynamic eccentricity / oil film gap.

[0025] The present invention has both the stable working state of the open type squeeze film damper integrated and a relatively simple design, and the characteristics of less air inhalation and sufficient lubricating oil extrusion of the closed type damper.

[0026] The beneficial effects of the present invention:

[0027] (1) The structure is simple. Based on the open type squeeze film damper, labyrinth teeth and a plastic material ring (or an easily worn material ring) are added, and the sealing structure of the closed type damper is not required, which is convenient for assembly;

[0028] (2) The vibration damping effect is good. Since a labyrinth seal structure is added at both ends of the damper, the air inhalation is reduced, and the oil film damping is improved compared with the open type damper;

[0029] (3) The oil film is sufficiently extruded. The labyrinth tooth structures at both ends prevent the lubricating oil from flowing out from both ends, reducing the leakage amount, and the oil film can be sufficiently extruded;

[0030] (4) The axial length is fully utilized. Different from the closed type damper which needs to discard a part of the axial length at both ends due to assembly reasons, the labyrinth teeth and the material ring are located at both ends, maximizing the utilization of the axial length and increasing the extrusion area;

[0031] (5) Sealing enhancement: The plastic material ring (or wear-resistant material ring) is deformed (or worn) due to the collision of the labyrinth teeth, forming small grooves, which form a complementary structure with the labyrinth teeth, enhancing the sealing effect.

[0032] (6) By controlling the thickness of the plastic material ring (or wear-resistant material ring), the working range of the damper is limited within 0.4 times the oil film clearance, maintaining a linear change in the oil film stiffness of the damper. Description of the drawings:

[0033] Figure 1 It is a schematic structural diagram of an open squeeze film damper in the prior art;

[0034] Figure 2 It is a schematic structural diagram of a closed squeeze film damper in the prior art;

[0035] Figure 3 It is a schematic structural diagram of the labyrinth seal type squeeze film damper in Embodiment 1 of the present invention;

[0036] Figure 4 In Embodiment 1 of the present invention Figure 3 Schematic diagram of the partial structure of Part I, where:

[0037] 1 - Elastic support, 2 - Damper outer ring, 3 - Rotor, 4 - Damper inner ring, 5 - Oil supply groove, 6 - Oil film, 7 - Oil supply hole, 8 - Labyrinth teeth, 9 - Plastic material ring. Detailed implementation manners:

[0038] The present invention will be further described in detail below in conjunction with the embodiments.

[0039] For the convenience of clearly understanding the present invention, a specific embodiment with the material ring being a plastic material is given below and the present invention is further described in detail.

[0040] A labyrinth seal type squeeze film damper, the elastic support is sleeved outside the bearing, a bearing housing is provided outside the bearing, the head of the elastic support is the damper inner ring, the bearing housing is the damper outer ring, the rotor is sleeved inside the bearing, the damper outer ring and the damper inner ring are in clearance fit, the clearance is the oil film clearance, an oil supply groove is provided on the damper outer ring, an oil supply hole is opened in the oil supply groove, and the oil supply hole is arranged above the oil film clearance, where: One of the following methods is adopted for the labyrinth seal of the damper:

[0041] (1) The circumferential direction of the end of the damper outer ring is provided with labyrinth teeth, the circumferential direction of the end of the damper inner ring is provided with a groove, a plastic material ring or a wear-resistant material ring is arranged in the groove, and the labyrinth teeth at the end of the damper outer ring are arranged corresponding to the material ring of the damper inner ring;

[0042] (2) A groove is circumferentially formed at the end of the outer ring of the damper, and a labyrinth seal is circumferentially provided at the end of the inner ring of the damper. A plastic material ring or a wear-resistant material ring is arranged in the groove, and the material ring at the end of the outer ring of the damper is arranged corresponding to the labyrinth seal of the inner ring of the damper.

[0043] The elastic support is concentrically installed with the rotor through a bearing.

[0044] The lubricating oil is ISO VG2 to form an oil film.

[0045] The depth of the groove formed in the outer or inner ring of the damper corresponds to the thickness of the plastic material ring or the wear-resistant material ring.

[0046] The bottom of the labyrinth seal is at the same level as the bottom of the oil film gap, and the top height of the labyrinth seal is slightly less than the oil film gap.

[0047] The longitudinal thickness of the plastic material ring or the wear-resistant material ring is reasonably designed according to the maximum unbalanced force received by the engine and is ≤ 0.4 times the oil film gap.

[0048] During the operation of the labyrinth seal squeeze film damper, the rotor rotates at a high speed, and the labyrinth seal squeezes the plastic material ring or the wear-resistant material ring. When it is a plastic material ring, the plastic material ring deforms, and after a tooth-shaped groove is formed on the surface of the plastic material ring, a closer fit relationship is formed with the labyrinth seal, strengthening the sealing effect. When it is a wear-resistant material ring, after contact and wear with the labyrinth seal, a wear groove is left on the ring, strengthening the sealing ability.

[0049] During the operation of the labyrinth seal squeeze film damper, by controlling the thickness of the plastic material ring or the wear-resistant material ring ≤ 0.4 times the oil film gap, an eccentricity ≤ 0.4 is achieved, where eccentricity = dynamic eccentricity / oil film gap.

[0050] Embodiment 1

[0051] A labyrinth seal squeeze film damper, the structural schematic diagram of which is as Figure 3 shown. The elastic support 1 and the rotor 3 are concentrically installed through a bearing. The head of the elastic support 1 serves as the inner ring 4 of the damper, and the bearing housing serves as the outer ring 2 of the damper. The two are in clearance fit, and the lubricating oil is filled into this clearance through the oil supply hole 7 and the oil supply groove 5 to form an oil film 6. The partial structural schematic diagram of part I is as Figure 4 shown. A labyrinth seal 8 is added at the end of the outer ring 2 of the damper, and a groove is formed at the corresponding end of the inner ring 4 of the damper and a plastic material ring 9 is installed in a circle. The labyrinth seal 8 and the plastic material ring 9 form an end sealing structure.

[0052] When specifically processing this embodiment, labyrinth teeth 8 with a height slightly less than the oil film clearance and a downward direction are machined at both ends of the outer ring 2 of the damper. The labyrinth teeth 8 and the inner ring 4 of the damper form a clearance fit to facilitate assembly. Grooves equal to the axial width of the labyrinth teeth are respectively machined at both ends of the inner ring 4 of the damper. The depth of the groove is reasonably designed according to the maximum unbalanced force received by the engine and should not be greater than 0.4 times the oil film clearance. A plastic material ring 9 with a thickness equal to the groove depth is installed on this groove to ensure that the upper surface of the plastic material ring 9 and the surface of the inner ring 4 of the damper are at the same height, and the labyrinth teeth 8 and the plastic material ring 9 also maintain a clearance fit. The inner ring 4 of the damper, the outer ring 2 of the damper, the labyrinth teeth 8, and the plastic material ring 9 together form an approximately closed annular clearance, and lubricating oil is injected into this clearance to form an oil film 6.

[0053] When the rotor 3 vibrates due to the unbalanced force, the labyrinth teeth 8 come into contact and collide with the plastic material ring 9, and the plastic material ring 9 undergoes a slight deformation. Due to the high rotational speed of the engine, the contact between the labyrinth teeth 8 and the plastic material ring 9 will occur thousands of times. The subtle deformations that occur each time are superimposed together, and finally small grooves will be formed on the plastic material ring 9. The small grooves are generated by the labyrinth teeth 8, their shape is the shape of the labyrinth teeth 8, and the depth is the maximum depth that the labyrinth teeth 8 can reach when the rotor 3 is subjected to the maximum unbalanced force. When the labyrinth teeth 8 come into contact with the plastic material ring 9 again, the labyrinth teeth 8 drop into the corresponding grooves (not necessarily reaching the bottom), and the radial clearance at the end of the damper decreases, further hindering the outward leakage of the lubricating oil. In other words, the deformation of the plastic material ring 9 not only does not weaken the sealing effect, but instead strengthens it. The lubricating oil leakage of the damper is reduced, the oil film pressure is increased, the damping of the damper is increased, and the vibration damping ability is improved. In addition, since the thickness of the plastic material ring is not greater than 0.4 times the oil film clearance, that is, the working range of the damper is within 0.4 times the oil film clearance, and the oil film stiffness changes linearly within this range, which is beneficial to the stability of the rotor system.

Claims

1. A labyrinth seal type squeeze film damper, sleeved outside a bearing, characterized in that It includes an elastic support. There is a bearing housing outside the bearing. The head of the elastic support is the inner ring of the damper. The bearing housing is the outer ring of the damper. A rotor is sleeved inside the bearing. The outer ring and the inner ring of the damper are in clearance fit, and the clearance is the oil film clearance. An oil supply groove is provided on the outer ring of the damper, and an oil supply hole is opened in the oil supply groove. The oil supply hole is arranged above the oil film clearance. Among them: The labyrinth seal of the damper adopts one of the following methods: (1) Labyrinths are circumferentially arranged at the end of the outer ring of the damper. A groove is circumferentially opened at the end of the inner ring of the damper. A plastic material ring or an easily worn material ring is arranged in the groove. The labyrinths at the end of the outer ring of the damper are arranged corresponding to the material ring of the inner ring of the damper; (2) A groove is circumferentially opened at the end of the outer ring of the damper. Labyrinths are circumferentially arranged at the end of the inner ring of the damper. A plastic material ring or an easily worn material ring is arranged in the groove. The material ring at the end of the outer ring of the damper is arranged corresponding to the labyrinths of the inner ring of the damper; The longitudinal thickness of the plastic material ring or the easily worn material ring ≤ 0.4 times the oil film clearance. Longitudinal means radial; Eccentricity = dynamic eccentricity / oil film clearance, and eccentricity ≤ 0.4; During the working process, the rotor rotates at a high speed, and the labyrinths squeeze the plastic material ring or the easily worn material ring. When it is a plastic material ring, the plastic material ring deforms. After a tooth-shaped groove is formed on the surface of the plastic material ring, a closer fit relationship is formed with the labyrinths, strengthening the sealing effect; when it is an easily worn material ring, after contact and wear with the labyrinths, a wear groove is left on the ring, strengthening the sealing ability.

2. The labyrinth seal type squeeze film damper according to claim 1, wherein The elastic support and the rotor are concentrically installed through the bearing.

3. The labyrinth seal type squeeze film damper according to claim 1, wherein, The depth of the groove opened on the outer or inner ring of the damper corresponds to the thickness of the plastic material ring or the easily worn material ring.

4. The labyrinth seal type squeeze film damper according to claim 1, characterized in that, The bottom of the labyrinth is horizontal with the bottom of the oil film clearance, and the top height of the labyrinth is less than the oil film clearance.

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