An interleaved seal tooth type squeeze film damper

Abstract

An interleaved seal tooth type squeeze film damper of the present invention is sleeved outside a bearing and 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, and the bearing housing is the outer ring of the damper. A rotor is installed inside the bearing. The outer ring of the damper 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. Sealing teeth are circumferentially provided at the ends of the outer ring and the inner ring of the damper, and the tips of the two groups of sealing teeth are engaged with each other. Through the reasonable design of the technical solution of the present invention, the sealing teeth of the inner and outer rings can be completely engaged, the upper and lower gaps are reduced, the oil outflow channel is restricted, the leakage amount is reduced, and the damping effect is greatly improved.

Description

Technical Field:

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

[0002] An aeroengine is a high-speed rotating machine composed of a rotor system. The severe working conditions such as high rotational speed, high air flow speed, and high temperature make the rotor system bear various complex and huge loads. This will cause the rotor imbalance caused by machining and assembly errors to be more prominent, the rotor vibration to intensify, posing a great hidden danger to the engine safety and also having an adverse impact on the engine performance, thus affecting the overall performance of the aircraft.

[0003] Currently, for the vibration reduction of the rotor system, a commonly used and effective method is to install a squeeze-film damper in the rotor system. This structure is very simple, occupies little space, and has good vibration reduction effect. It has been actually applied to aeroengines for decades. 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 oil film. When the rotor is subjected to an unbalanced force, the journal will squeeze the oil film, and the oil film generates a reaction force to absorb part of the vibration energy, reducing the energy transmitted from the rotor to the elastic support, thereby playing a vibration reduction role.

[0004] Squeeze-film dampers are divided into two types: open type and closed type according to whether there are end seals.

[0005] The structural schematic diagram of an open squeeze-film damper is as shown in Figure 1 shown. It has a simple structure and good vibration reduction effect, so it has been widely used. However, the open damper also has disadvantages:

[0006] 1) The open damper has no end seals at both ends, and the lubricating oil directly flows out from both ends. The lubricating oil at both ends is not squeezed as fully as the lubricating oil in the middle, and the pressure is not as high as that of the lubricating oil in the middle. The overall oil film damping is relatively small.

[0007] 2) Both ends of the open damper are directly exposed to the atmosphere. When one side of the oil film is squeezed, the pressure of the oil film on this side increases, and the pressure of the oil film on the other side decreases. If this pressure drops below the atmospheric pressure, air will be sucked into the damper due to the pressure difference, forming an air inhalation phenomenon. Air inhalation will reduce the effective squeezing area of the oil film, thereby reducing the oil film damping.

[0008] The structural schematic diagram of a closed squeeze-film damper is as shown in Figure 2 shown. Due to the presence of seals at the ends, the air inhalation phenomenon is not serious, and the leakage of lubricating oil is also less than that of the open damper. However, the closed damper still has disadvantages:

[0009] 1) The closed damper adds seals such as piston rings, making its structure more complex than that of the open damper. This increases the difficulty of design and manufacturing, and its operation is not as stable and reliable as that of the open damper.

[0010] 2) The closed damper leaves an axial length at both ends to facilitate slotting for installing seals. The oil film extrusion at both ends is insufficient, and the axial length is not fully utilized.

[0011] Therefore, adding a sealing structure at both ends of the damper can avoid problems such as air inhalation in the open damper. Making the sealing structure integral with the inner and outer rings of the damper and placing it at both ends can increase the working stability of the damper and the fully extruded area of the oil film. At the same time, the added sealing structure controls the working amplitude of the damper not to exceed 0.4 times the oil film gap to obtain a linear oil film stiffness, which is beneficial to the stability of the rotor. Summary of the Invention:

[0012] The object of the present invention is to overcome the deficiencies of the above-mentioned existing technologies and provide a squeeze film damper with staggered sealing teeth.

[0013] Based on the open squeeze film damper, the present invention adds a ring of staggered and complementary sealing teeth at both ends of the inner and outer rings of the damper. The sealing teeth are exposed to the air in their natural state. Given different design requirements of the damper, the shape of the sealing teeth is not restricted, as long as they are complementary in shape. To balance sealing performance and assembly convenience, the height of the sealing teeth on the inner and outer rings each accounts for half of the oil film thickness. When the rotor is subjected to an unbalanced force and squeezes the oil film, the inner ring sealing teeth of the damper will move towards the outer ring sealing teeth. The inner and outer ring sealing teeth will engage with each other according to the pre-designed vacancies. Through the reasonable design of the technical solution of the present invention, the inner and outer ring sealing teeth can fully engage, the upper and lower gaps are reduced, the oil outflow channel is restricted, the leakage is reduced, and the damping is increased.

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

[0015] A staggered sealing tooth type squeeze film damper is sleeved outside the bearing and includes 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 installed 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 gap. The outer ring of the damper is provided with an oil supply groove, and an oil supply hole is opened in the oil supply groove. The oil supply hole is arranged above the oil film gap. Sealing teeth are circumferentially arranged at both ends of the outer and inner rings of the damper, and the tips and bottoms of the two groups of sealing teeth are complementary.

[0016] The height of the sealing teeth each accounts for half of the oil film thickness, and the proportion of the length of the sealing teeth in the axial length is determined according to specific application requirements.

[0017] The elastic support member and the rotor are concentrically installed through bearings.

[0018] The lubricating oil is ISO VG2 to form an oil film.

[0019] The sealing teeth are isosceles triangle sealing teeth or isosceles trapezoid sealing teeth.

[0020] During the operation of the staggered sealing tooth type squeeze film damper, the rotor rotates at a high speed, and the two sets of staggered sealing teeth engage to form a tight fit relationship, strengthening the sealing effect.

[0021] Advantages of the present invention:

[0022] (1) The structure is simple. Staggered sealing teeth are added on the basis of an open type squeeze film damper. Structural parameters such as the shape and number of the sealing teeth can be reasonably designed and selected according to the actual situations such as the size of the damper and the processing technology, as long as the sealing teeth are distributed in a staggered and complementary manner and can engage tightly up and down.

[0023] (2) The sealing effect is good. Since the upper and lower sealing teeth are complementary to each other, they can engage completely with each other, with a good sealing effect. It can seal the end of the oil film to the greatest extent, reduce air inhalation, increase the oil film pressure, and improve the oil film damping.

[0024] (3) The oil film is fully squeezed. The sealing structures at both ends prevent the leakage of lubricating oil, and the middle oil film is fully squeezed.

[0025] (4) The axial length is fully utilized. The sealing structure is located at the outlet at both ends of the damper, and the middle is the effective length of the oil film, maximizing the utilization of the axial length and increasing the effective squeezing area.

[0026] (5) The oil film stiffness is maintained to change linearly. The length of the upper and lower sealing teeth is 0.5 times the oil film clearance, that is, the maximum working amplitude of the damper is 0.5 times the oil film clearance, which is close to the optimal working range of 0.4 times the oil film clearance, restricting the growth of the working amplitude of the damper, ensuring the linear change of the oil film stiffness, and suppressing the non-linearity. Description of the drawings:

[0027] Figure 1 It is a schematic structural diagram of an open type squeeze film damper in the prior art;

[0028] Figure 2 It is a schematic structural diagram of a closed type squeeze film damper in the prior art;

[0029] Figure 3 It is a schematic structural diagram of the staggered sealing tooth type squeeze film damper according to Embodiment 1 of the present invention;

[0030] Figure 4 In Embodiment 1 of the present invention Figure 3Schematic diagram of the partial structure of part I, where:

[0031] 1 - Elastic support, 2 - Outer ring of damper, 3 - Rotor, 4 - Inner ring of damper, 5 - Oil supply groove, 6 - Oil film, 7 - Oil supply hole, 8 - Outer ring sealing teeth, 9 - Inner ring sealing teeth. Specific implementation method:

[0032] The present invention will be further described in detail below with reference to the embodiments.

[0033] An interlaced sealing tooth 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 inner ring of the damper, the bearing housing is the outer ring of the damper, a rotor is installed inside the bearing inner ring, the outer ring of the damper and the inner ring of the damper are in clearance fit, the clearance is the oil film clearance, an oil supply groove is provided on the outer ring of the damper, an oil supply hole is opened in the oil supply groove, the oil supply hole is arranged above the oil film clearance, sealing teeth are circumferentially arranged at the ends of the outer ring and the inner ring of the damper, and the tips and bottoms of the two groups of sealing teeth are complementary;

[0034] The height of the sealing teeth each accounts for half of the oil film thickness, and the proportion of the length of the sealing teeth in the axial length is determined according to specific application requirements;

[0035] The elastic support and the rotor are concentrically installed through the bearing;

[0036] The lubricating oil is ISO VG2 to form an oil film;

[0037] The sealing teeth are isosceles triangle sealing teeth or isosceles trapezoid sealing teeth.

[0038] During the working process of the interlaced sealing tooth type squeeze film damper, the rotor rotates at a high speed, and the two groups of interlaced sealing teeth bite, forming a tight fit relationship to enhance the sealing effect.

[0039] Embodiment 1

[0040] Since the structural parameters such as the shape and number of the sealing teeth vary with the actual situation, for the convenience of clearly understanding the present invention, the sealing teeth with an isosceles triangle shape are given as an example for illustration below.

[0041] An interlaced sealing tooth type squeeze film damper, the schematic diagram of its structure is as Figure 3 shown. The head of the elastic support 1 is used as the inner ring 4 of the damper, and the inner ring of the bearing housing is used as the outer ring 2 of the damper, and the two are in clearance fit. The lubricating oil is injected into the clearance through the oil supply hole 7 and the oil supply groove 5 to form an oil film 6. The schematic diagram of the partial structure of part I is as Figure 4As shown, at both ends of the inner ring 4 and the outer ring 2 of the damper, inner ring sealing teeth 9 and outer ring sealing teeth 8 are machined, both of which are isosceles triangles, and the upper and lower sealing teeth are staggered, with the tooth tips facing the tooth bottoms.

[0042] The heights of the outer ring sealing teeth 8 and the inner ring sealing teeth 9 each account for half of the oil film thickness. Most of the exchange channels between the lubricating oil and the outside air are occupied by the sealing teeth, which hinders the natural outflow of the lubricating oil and the inhalation of outside air. When the oil film 6 is squeezed by the unbalanced force transmitted from the rotor 3, the inner ring sealing teeth 9 move towards the outer ring sealing teeth 8, the tooth tips enter the tooth bottoms, the exchange channels between the lubricating oil and the outside air are further compressed, it is difficult for the internal lubricating oil to flow out, the oil film is squeezed more fully, the lubricating oil pressure rises, the difference from the outside atmospheric pressure decreases, it is difficult for outside air to enter, the air inhalation decreases, the effective squeezing area of the oil film increases, providing greater damping to reduce vibration. In addition, due to the limitation of the sealing tooth length, the working range of the damper is limited within 0.5 times the oil film clearance, the oil film stiffness can be approximately considered to change linearly, the system stability is improved, and the engine performance is improved.

Claims

1. An interleaved seal tooth type squeeze film damper is sleeved outside a bearing. It is characterized in that it includes 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 of the damper 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. An oil supply hole is opened in the oil supply groove, and the oil supply hole is arranged above the oil film clearance. A set of seal teeth are circumferentially arranged at the ends of the outer ring and the inner ring of the damper, and the two sets of seal teeth are staggered. The tooth tip of one set of seal teeth is opposite to the tooth bottom of the other set of seal teeth. The height of the seal teeth each accounts for half of the oil film thickness.

2. The interleaved seal tooth type squeeze film damper according to claim 1, it is characterized in that the elastic support and the rotor are concentrically installed through a bearing.

3. The interleaved seal tooth type squeeze film damper according to claim 1, it is characterized in that the seal teeth are isosceles triangle seal teeth or isosceles trapezoid seal teeth.

4. The interleaved seal tooth type squeeze film damper according to claim 1, it is characterized in that during the working process of the interleaved seal tooth type squeeze film damper, the rotor rotates at a high speed, and the two sets of interleaved seal teeth achieve different degrees of engagement, forming a tight fit relationship to enhance the sealing effect.

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