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CN-122014752-A - Novel foil gas dynamic pressure bearing and bearing vibration control method

CN122014752ACN 122014752 ACN122014752 ACN 122014752ACN-122014752-A

Abstract

The invention belongs to the field of bearings, and particularly relates to a novel foil pneumatic dynamic pressure bearing and a bearing vibration control method, which comprise a bearing sleeve, wherein a preload control structure is arranged on the inner wall of the bearing sleeve; the inner wall elastic connection of bearing housing has the ripples foil, the surface elastic connection of ripples foil has a top foil, the inner wall of top foil has cup jointed the rotor, the mounting groove position of adaptation preload control structure has been seted up to the inside of bearing housing. According to the novel foil pneumatic dynamic pressure bearing and the bearing vibration control method, when voltage is applied to the piezoelectric ceramic, the piezoelectric ceramic deforms due to the self inverse piezoelectric effect, so that the input end of the lever amplifying mechanism is pushed, the output end of the lever amplifying mechanism extrudes the wave foil, and the wave foil deforms to deform the top foil, so that real-time adjustment of air pressure distribution, rigidity and damping can be realized.

Inventors

  • DAI HE
  • LIAO XUHUI
  • RONG CHAO
  • MA JINGYU

Assignees

  • 安徽日飞轴承有限公司

Dates

Publication Date
20260512
Application Date
20260331

Claims (10)

  1. 1. The novel foil pneumatic dynamic bearing comprises a bearing sleeve (1) and is characterized in that a preload control structure (4) is arranged on the inner wall of the bearing sleeve (1); The inner wall elastic connection of bearing housing (1) has ripples foil (3), the surface elastic connection of ripples foil (3) has top foil (5), rotor (2) have been cup jointed to the inner wall of top foil (5).
  2. 2. The novel foil pneumatic dynamic bearing of claim 1, wherein the bearing sleeve (1) is internally provided with an installation groove position which is matched with the preload control structure (4).
  3. 3. The novel foil pneumatic dynamic pressure bearing of claim 1, wherein the preload control structure (4) comprises a lever amplification mechanism (401), the lever amplification mechanism (401) is fixedly connected with the inside of the bearing sleeve (1) through a flexible hinge (403), the flexible hinge (403) is fixedly connected with the output end of the piezoelectric ceramic actuator (402), a locking screw (404) is connected with the inner wall of the bearing sleeve (1) in a threaded manner, the surface of the locking screw (404) is sleeved with one end of a spring (405), the other end of the spring (405) is tightly attached to the surface of a steel ball (406), and the surface of the steel ball (406) is tightly attached to the surface of the lever amplification mechanism (401).
  4. 4. The novel foil pneumatic dynamic bearing as claimed in claim 1, wherein the preload control structure (4) is provided with a plurality of groups and is arranged in a circumferential array in the bearing housing (1).
  5. 5. The novel foil gas dynamic pressure bearing vibration control method is characterized by comprising the following steps of: s1, determining geometric parameters and material properties of a pneumatic foil bearing, and determining a mass matrix, a stiffness matrix and initial test conditions of the foil; S2, substituting the geometric parameters and the material properties determined in the S1 into a lubrication motion equation, a continuity equation and a state equation, so as to deduce a Reynolds equation of the gas dynamic pressure foil bearing, inputting parameters related to the corrugated foil and the top foil, establishing a gas film thickness equation, and calculating the gas film thickness of the foil bearing; s3, establishing a dynamic characteristic mathematical model of the aerodynamic foil bearing through the foil mass matrix and the stiffness matrix in the S1 and the air film thickness equation parameter and the tiny unbalanced disturbance parameter of the S2 to obtain a dynamic characteristic coefficient differential equation; S4, establishing a dynamic model of the bearing-rotor system by taking the geometric parameters and the material properties determined in the S1 and the system parameters such as the dynamic characteristic coefficient of the bearing, the rotor mass, the rotating speed and the like of the S3 into the dynamic model of the bearing-rotor system, and analyzing the dynamic characteristic and the stability of the system; S5, inputting the foil stiffness matrix of S1, the air film thickness equation of S2 and the preloading control substructure parameters, establishing a preloading control structure mechanical model, and combining the equivalent elastic stiffness model of the elastic supporting structure to obtain the coupling relation of radial preloading, foil deformation and air film thickness; S6, inputting an ideal model established by the coupling relation of S5, the system stability analysis result of S4 and the real-time data acquired by the sensor, constructing a closed-loop vibration control system based on a PID algorithm, solving a convergence condition through a least square iterative operation, and adjusting the air film pressure distribution, the foil structure deformation and the bearing radial preload deviation according to the convergence condition to realize active control of the foil gas dynamic pressure bearing vibration.
  6. 6. The method according to claim 5, wherein in S2, the reynolds equation of the hydrodynamic foil bearing is: wherein x is the circumferential coordinate of the bearing, Z is the axial coordinate of the bearing, P is the pressure of the air film, the unit is Pa, H is the thickness of the lubricating air film, the unit is m, Mu is the dynamic viscosity of the gas, the unit is Pa.s, U is the axial speed of the journal in m/s.
  7. 7. The method for controlling vibration of a novel foil gas dynamic pressure bearing according to claim 5, wherein the air film thickness calculation equation in S2 is: wherein alpha is the foil deformation coefficient; e is the modulus of elasticity of the bump foil, the unit is Pa, S is the length of the bump foil, the unit is m, L is the corrugated length of the bump foil, the unit is m, C is the radial clearance, in m, For the bump foil thickness, in m, V is the poisson ratio of the bump foil.
  8. 8. The method for vibration control of a novel foil gas dynamic pressure bearing according to claim 5, wherein the differential equation of the dynamic characteristic coefficient in S3 is: Wherein, the Is a rigidity coefficient reflecting the elastic restoring force characteristic of the system, Is a damping coefficient, reflects the energy dissipation characteristics of the system, In order for the acceleration to be a function of the acceleration, In order to be able to achieve a speed, Is displacement.
  9. 9. The method according to claim 5, wherein the dynamic characteristic coefficient differential equation in S4: Wherein, the Is the unbalanced mass of the rotor, the unit is kg, E is the eccentricity of the unbalanced mass, in m, The rotational angular velocity of the rotor, in rad/s, For excitation angular frequency, in rad/s, The initial phase angle, in rad, Representing the stiffness coefficient of the bearing-rotor system, Representing the damping coefficient of the bearing-rotor system.
  10. 10. The method for controlling vibration of a novel foil pneumatic dynamic bearing according to claim 5, wherein in the step S5, the preload control sub-structure parameters comprise piezoelectric ceramic voltage input expansion and contraction amount, lever amplification factor of a lever amplification mechanism and spring preload; In the step S6, the real-time data collected by the sensor comprises air film pressure, foil deformation and rotor displacement.

Description

Novel foil gas dynamic pressure bearing and bearing vibration control method Technical Field The invention relates to the technical field of bearings, in particular to a novel foil pneumatic dynamic pressure bearing and a bearing vibration control method. Background At present, the foil gas dynamic pressure bearing is widely applied to ultrahigh-speed rotating equipment due to the advantages of high rotating speed, long service life, oil-free lubrication, compact structure and the like, and the core principle is that an elastic foil is matched with a rigid bearing sleeve, and a gas dynamic pressure effect is utilized to form a supporting gas film suspension rotor, so that DN (digital number) value (rotor surface linear speed), energy density and efficiency of rotating machinery can be remarkably improved. In the prior art, conventional foil gas dynamic bearings are typically "passive" foil gas dynamic bearings, which improve the performance mainly by optimizing the foil structure (e.g. wave foil type, flat foil type, cantilever type, etc.), adjusting the radial gap or adding damping elements (e.g. wire mesh blocks, viscoelastic foils). For example, the corrugated foil type bearing developed by the korean national institute of science and technology in combination with the corporation improves the load bearing capacity by optimizing the corrugated foil stiffness distribution, but there are some inherent drawbacks. If the performance can not be adjusted according to the working condition, the structure and the performance of the assembled bearing are fixed, and the bearing can not be actively adjusted according to the working condition (such as rotating speed and load change) of equipment, so that the stability is easy to be reduced when the working condition fluctuates. Subsynchronous vibration is not sufficiently restrained, and under the working condition of high DN value, large-amplitude subsynchronous vibration is easy to occur to a rotor system due to the nonlinearity of an air film and the nonlinearity of a foil structure, so that the high-speed stability of the system is weakened, and the application range of the bearing is limited. And also has the problem of poor adaptability because passive designs have difficulty matching rotor systems with complex dynamic response, such as inability to optimize support stiffness and damping in real time as rotor imbalance mass changes or static load fluctuates. In addition, few researches try to form a hybrid bearing by combining a magnetic suspension bearing and a gas dynamic pressure foil bearing, but the gas dynamic pressure foil bearing is only used as an auxiliary support, active control is not realized, and the hybrid bearing has a complex structure and high cost and is difficult to widely apply. In view of the above, we propose a novel foil gas dynamic pressure bearing and a method of controlling vibration of the bearing. Disclosure of Invention The invention mainly aims to provide a novel foil gas dynamic pressure bearing and a bearing vibration control method, which can solve the problems in the background technology. In order to achieve the above purpose, the novel foil pneumatic dynamic bearing provided by the invention comprises a bearing sleeve, wherein the inner wall of the bearing sleeve is provided with a preload control structure; The inner wall of the bearing sleeve is elastically connected with a wave foil, the surface of the wave foil is elastically connected with a top foil, and the inner wall of the top foil is sleeved with a rotor. Preferably, the bearing sleeve is internally provided with a mounting groove adapted to the preload control structure. Preferably, the preload control structure comprises a lever amplifying mechanism, and the lever amplifying mechanism can effectively amplify the tiny telescopic deformation of the piezoelectric ceramic actuator and convert the tiny telescopic deformation into effective travel which is enough to adjust the radial preload and the local assembly clearance of the bearing. The lever amplifying mechanism is fixedly connected with the inside of the bearing sleeve through a flexible hinge, the lever amplifying mechanism is used as a key transmission part of the preload control structure, can transfer micro telescopic deformation of the piezoelectric ceramic actuator without gaps, is matched with the lever amplifying mechanism to accurately convert the deformation into radial preload adjustment quantity of the wave foil and the top foil, ensures the adjustment precision of radial preload and assembly gaps, lays a structural foundation for the precision of vibration control, realizes motion guidance through self elastic deformation, has no mechanical friction and gaps, and reduces vibration and noise caused by transmission clamping and loosening. The flexible hinge is fixedly connected with the output end of the piezoelectric ceramic actuator, the inner wall of the bearing sleeve is in threaded connection